Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Sanders: Mosby's Paramedic Textbook, Revised 3rd Edition PowerPoint Lecture Notes Chapter 29: Cardiology Chapter 29 Cardiology Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Objectives z Identify risk factors and prevention strategies for cardiovascular disease z Describe cardiovascular physiology z Discuss cardiac electrophysiology z Outline the electrical conduction system of the heart z Outline cardiovascular assessment Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Objectives z Describe ECG monitoring techniques z Explain how the ECG tracing relates to the heart’ heart’s electrical activity z Describe the steps in ECG interpretation z Identify features of normal sinus rhythm z Interpret ECG tracings, including rhythm, site, causes, significance, and prehospital management Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 1 Objectives z Describe assessment and management of patients with cardiovascular disorders z List relevant information for cardiovascular pharmacological agents z Identify actions to be taken for prehospital termination of resuscitation Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Objectives z List indications, contraindications, and prehospital considerations for: Basic life support MonitorMonitor-defibrillators ¾ Implantable cardiovertercardioverter-defibrillators ¾ Synchronized cardioversion ¾ Transcutaneous cardiac pacing ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Scenario An elderly, diabetic female is complaining of weakness and an “aching” aching” feeling in her chest. She is pale, diaphoretic, and has a blood pressure of 100/70 mm Hg, P is 110/min; and blood sugar is 90 mg/dL. You prepare to perform a 1212-lead ECG as your partner starts an IV after placing her on oxygen. Suddenly, her eyes roll back and her head slumps limply to the side. As you realize she has no carotid pulse, you note a chaotic rhythm on the monitor and recognize that she is in ventricular fibrillation. Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 2 Discussion z List this patient’ patient’s risk factors for cardiovascular disease. z Describe the steps in initial cardiac care that were indicated on this call? z What changes on the 1212-lead would have confirmed myocardial infarction? z Outline steps that need to be taken now that her condition has changed. Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Cardiovascular Disease Age Family history Diabetes Hypertension Hyperlipidemia High cholesterol z z z z z z z z z z Cigarette smoking Preexisting cardiac disease Cocaine use Carbohydrate intolerance Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Heart Anatomy z Muscular pump ¾ ¾ Two atria Two ventricles z Cone shape z Size of closed fist Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 3 Heart Anatomy In mediastinum of thoracic cavity z ¾ 2/3 of heart's mass lies left of midline of sternum Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Pericardium z Fibrous outer layer, thin inner layer surround heart z Cavity between layers contains pericardial fluid ¾ Reduces friction Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Coronary Vessels z Seven large veins carry blood to the heart ¾ ¾ z Pulmonary veins Superior and inferior vena cavae Coronary sinus Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 4 Coronary Vessels z Aorta z Pulmonary trunk z Coronary arteries supply heart muscle Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Heart Chambers and Valves z Septum separates right and left chambers ¾ ¾ Interatrial septum Interventricular septum Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Atrioventricular Valves z Allow blood flow from atria into ventricles z Prevent backflow z Tricuspid valve z Mitral (bicuspid) valve Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 5 Semilunar Valves z Aortic and pulmonary semilunar valves ¾ ¾ ¾ Block blood flow Blood pushes against valves, forcing them open Blood flowing from aorta or pulmonary trunk causes valves to close Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Peripheral Circulation z Flow of blood Ventricles Arteries ¾ Arterioles ¾ Capillaries ¾ Venous system ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Capillary Network z Blood supplied to capillary network by arterioles z Blood flows through network into venules ¾ z Regulated precapillary sphincters Exchange nutrients and wastes Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 6 Arteries and Veins z Three layers in all blood vessel walls (except capillaries and venules) Tunica intima • Inner layer ¾ Tunica media • Middle layer ¾ Tunica adventitia • Outer layer ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Types of Arteries z Conducting arteries ¾ z Distributing arteries ¾ z Large Small to medium Arterioles ¾ Smallest Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Venules z Similar to capillaries z Collect blood from capillaries and transport to small veins z Nutrient exchange across walls of venules Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 7 Veins z Walls are layer of smooth muscle cells z MediumMedium-sized and large veins ¾ Carry blood to venous trunks and then the heart z Large veins ¾ ¾ Valves allow blood flow to but not from the heart Prevents backflow of blood Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Arteriovenous Anastomoses (AV Shunts) z Allows blood flow from arteries to veins ¾ z Natural AV shunts ¾ ¾ z Without passing through capillaries Sole of foot and nail beds Regulate body temperature Pathological shunts ¾ Injury or tumors Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Coronary Arteries z Supply arterial blood to heart muscle ¾ ¾ z Left coronary artery carries about 85% of blood supply to myocardium Right coronary artery carries remainder Originate above aortic valve Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 8 Left Coronary Artery z Divides into left anterior descending and circumflex arteries ¾ Left anterior descending (LAD) supplies: • Anterior wall of left ventricle ¾ • Interventricular septum Circumflex supplies: • Lateral and posterior portions of left ventricle • Part of right ventricle Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Coronary Arteries z Right coronary artery and left anterior descending artery supply: ¾ ¾ z Most of right atrium and ventricle Inferior aspect of left ventricle Anastomoses provide collateral circulation Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Coronary Capillaries z Exchange nutrients and metabolic wastes z Merge to form coronary veins z Coronary sinus empties into right atrium ¾ Major vein draining myocardium Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 9 Physiology z Heart is two pumps in one: LowLow-pressure pump (right atrium and right ventricle) • Supplies pulmonary vasculature ¾ HighHigh-pressure pump (left atrium and left ventricle) • Supplies systemic vasculature ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Blood Flow through the Heart z Blood enters right atrium from systemic circulation by inferior and superior vena cavae and from the heart by the coronary sinus z Blood passes into right ventricle z Ventricles push blood against tricuspid and semilunar valves z Blood enters pulmonary trunk Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Blood Flow through the Heart z Pulmonary arteries carry blood to lungs ¾ ¾ Carbon dioxide released Oxygen picked up z Blood enters left atrium through pulmonary veins z Left atrium contracts and fills ventricles z Blood enters aorta and is sent through body Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 10 Cardiac Cycle z Systole ¾ ¾ z Atrial Ventricular Diastole ¾ ¾ Atrial Ventricular Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Heart Action during Atrial Systole Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Heart Action during Ventricular Systole Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 11 Cardiac Output z Stroke volume z Heart rate z Contractility z Starling's law Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Nervous System Control of the Heart z Extrinsic control by parasympathetic and sympathetic nerves influences: Heart rate Conductivity ¾ Contractility ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Nervous System Control of the Heart z Sympathetic and parasympathetic nerve fibers in atria z Ventricles mainly have sympathetic nerves Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 12 Sympathetic Control z Postganglionic sympathetic fibers release norepinephrine; have effects on myocardium: Inotropic Dromotropic ¾ Chronotropic ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Sympathetic Control z Sympathetic stimulation of the heart Dilation of coronary blood vessels Constriction of peripheral vessels ¾ Increased oxygen demands of the heart met by increase in blood and oxygen supply ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Sympathetic Control z Norepinephrine release results from stimulation of alphaalpha- and betabeta-adrenergic receptors in the heart z Sympathetic stimulation increases the heart rate Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 13 Parasympathetic Control z Parasympathetic innervation of the heart by vagus nerve ¾ Continuous inhibitory influence on the heart by decreasing heart rate and contractility Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Hormonal Regulation of the Heart z Sympathetic impulses are transmitted to adrenal medulla and blood vessels ¾ Adrenal medulla secretes epinephrine and norepinephrine Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Epinephrine z Epinephrine increases rate and force of contraction z Epinephrine also: Constricts blood vessels in skin, kidneys, GI tract, and other organs ¾ Dilates skeletal and coronary vessels ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 14 Norepinephrine z Causes constriction of peripheral blood vessels in most areas of the body z Stimulates cardiac muscle Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Role of Electrolytes z Myocardial cells bathed in electrolyte solution z Electrolytes that influence cardiac function: Calcium Potassium ¾ Sodium ¾ Magnesium ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Electrophysiology of the Heart z Two cell types in myocardium Cells of electrical conduction system • Formation and conduction of electric current ¾ Working myocardial cells • Contractility ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 15 Electrical Activity of Cardiac Cells z Ions are charged particles that are electrically positive or negative ¾ ¾ Cations Anions Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Electrical Activity of Cardiac Cells z Charged particles are like magnets: Need energy to push apart if opposite electrical charges ¾ Need energy to join if like electrical charges ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Membrane Potentials z MagneticMagnetic-like attraction gives separated particles of opposite charges potential energy ¾ ¾ Membrane potential between inside and outside of cell Charge between inside and outside of cells expressed in millivolts (mV) Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 16 Resting Membrane Potential z Cell in “resting” resting” state z Has electrical charge difference ¾ ¾ Resting membrane potential (RMP) Inside of cell is negative compared to outside of cell membrane Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Resting Membrane Potential z RMP due to difference between intracellular and extracellular potassium ion level Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Depolarization z Sodium— Sodium—Positively charged ion on outside of cell ¾ ¾ Chemical and electrical gradient Tends to move intracellularly Sodium channels remain closed in resting cell membrane Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 17 Depolarization z Depolarization (electrical conduction) takes place when sodium rushes into the cell, making inside more positive compared with outside Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Depolarization Depolarization of cell membrane causes sodium channels to open Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Diffusion through Ion Channels z Cell membrane is: Relatively permeable to potassium Less permeable to calcium chloride ¾ Minimally permeable to sodium ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 18 Diffusion through Ion Channels z ProteinProtein-lined channels allow passage of ions through cell membrane z Permeability influenced by: Electrical charge Size ¾ Gating proteins ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. SodiumSodium-Potassium Pump z Actively pumps sodium ions out of cell and potassium ions into cell z Transports three sodium ions out for every two potassium ions taken in z Returns cell to its resting state Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. SodiumSodium-Potassium Exchange Pump Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 19 Channels in Cardiac Muscle Cells z Sodium and calcium ions enter cells through two separate channel systems in cell membrane: ¾ ¾ Fast channels Slow channels Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Channels z Fast channels are sensitive to small changes in membrane potential As cell nears threshold level: • Fast sodium channels open ¾ Sodium ions rush intracellularly • Rapid depolarization ¾ z Slow channels are selectively permeable to calcium and sodium Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Cell Excitability z Nerve and muscle cells are capable of producing action potential z Threshold potential Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 20 Propagation of Action Potential z Action potential on cell membrane stimulates adjacent cell membrane Excitation process is spread along length of cell and on to the next ¾ AllAll-oror-none principle ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Cardiac Action Potential z Phase 0 (rapid depolarization phase) z Phase 1 (early rapid depolarization phase) z Phase 2 (plateau phase) z Phase 3 (terminal phase of rapid repolarization) z Phase 4 (resting period) Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Action Potential of Myocardial Cells Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 21 Absolute Refractory Period z Absolute refractory period ¾ z Cardiac muscle cell is completely insensitive to stimulation Refractory period of ventricles is about same duration as action potential Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Relative Refractory Period z Muscle cell is more difficult than normal to excite but can still be stimulated Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Electrical Conduction System z Sinoatrial node (SA node) z Atrioventricular (AV) junction ¾ ¾ z AV node Bundle of His HisHis-Purkinje system ¾ Bundle branches • Right • Left anterior fascicle • Left posterior fascicle Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 22 Characteristics of Myocardial Cells z Automaticity z Excitability z Conductivity z Contractility Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Intrinsic Rates z SA node ¾ z AV junctional tissue ¾ z 6060-100/min 4040-60/min Ventricles (bundle branches and Purkinje fibers) ¾ 2020-40/min Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Ectopic Electrical Impulse Formation z Ectopic beat results when pacemaker function is assumed by cells other than in SA node ¾ ¾ Premature beats Early in diastole before SA node is scheduled to discharge Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 23 Ectopic Electrical Impulse Formation z Premature beats Atrial origin— origin—Premature atrial complexes (PACs) Junctional origin— origin—Premature junctional complexes (PJCs) ¾ Ventricular origin— origin—Premature ventricular complexes (PVCs) ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Ectopic Electrical Impulse Formation z Two mechanisms for ectopic impulse generation in the heart: ¾ ¾ Enhanced automaticity Reentry Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Enhanced Automaticity z Acceleration in depolarization z Due to high leakage of sodium ions into cells ¾ ¾ z Cells reach threshold prematurely Rate of impulse formation in potential pacemakers increases beyond their inherent rate Causes dysrhythmias in Purkinje fibers ¾ Other myocardial cells Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 24 Enhanced Automaticity Excess catecholamines Digitalis toxicity Hypoxia Hypercapnia Myocardial ischemia or infarction Increased venous return (preload) Hypokalemia or electrolyte abnormalities Atropine administration z z z z z z z z Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Reentry z Reactivation of myocardial tissue by same impulse z Occurs when electrical impulse is delayed, blocked in segments of the heart's electrical conduction system Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Reentry Conduction through normal and severely depressed Purkinje fibers Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 25 Reentry z Reentry dysrhythmias can occur in: SA node Atria ¾ AV junction ¾ Bundle branches ¾ Purkinje fibers ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Delayed Impulses z Causes of delayed or blocked impulses Myocardial ischemia Certain drugs ¾ Hyperkalemia ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Assessment of Cardiac Patient z Chief complaint z History of event and significant past medical history z Physical exam Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 26 Chief Complaint z Cardiac disease chief complaints Chest pain or discomfort • Shoulder, arm, neck, or jaw pain or discomfort ¾ Dyspnea ¾ Syncope ¾ Abnormal heart beat or palpitations ¾ May vary ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Chest Pain or Discomfort z Common chief complaint in myocardial infarction z Noncardiac causes of chest pain Pulmonary embolus Pleurisy ¾ Reflux esophagitis ¾ ¾ z History of chest pain is important ¾ OPQRST method Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Dyspnea z May occur with myocardial infarction z Symptom of heart failure z Dyspnea unrelated to heart disease Chronic obstructive pulmonary disease Respiratory infection ¾ Pulmonary embolus ¾ Asthma ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 27 Dyspnea z Factors important to differentiate dyspnea: Duration Circumstances of onset ¾ What aggravates or relieves, including medications ¾ Previous episodes ¾ Associated symptoms ¾ Orthopnea ¾ Prior cardiac problems ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Syncope z Sudden decrease in cerebral perfusion z Cardiac causes decrease cardiac output ¾ Dysrhythmias Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Syncope z Noncardiac causes of syncope Stroke Drug or alcohol intoxication ¾ Aortic stenosis ¾ Pulmonary embolism ¾ Hypoglycemia ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 28 Syncope— Syncope—History Aura (nausea, weakness, lightheadedness) Circumstances z z ¾ ¾ ¾ Position before event Pain Stress Duration of syncopal episode Symptoms before syncope Other symptoms Previous episodes z z z z Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Palpitations z Sometimes normal z May indicate serious dysrhythmia Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Palpitations z History and physical exam Pulse rate (if obtained) Regular versus irregular rhythm ¾ Circumstances ¾ Duration ¾ Chest pain, diaphoresis, syncope, confusion, dyspnea ¾ Previous episodes ¾ Medications ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 29 Significant Past Medical History z Is the patient taking prescription medications, particularly cardiac medications? Digoxin Furosemide (or other diuretics) ¾ Nitroglycerin ¾ Beta blockers ¾ ¾ z Is the patient being treated for any other illness? Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Significant Past Medical History z Has the patient ever had: Myocardial infarction or angina pectoris Coronary artery bypass procedure or angioplasty ¾ Implanted pacemaker or ICD ¾ Heart failure ¾ Hypertension ¾ Diabetes ¾ Chronic lung disease ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Significant Past Medical History z Allergies z Other risk factors for cardiac event z Implanted pacemaker or implantable cardiovertercardioverter-defibrillator (ICD) Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 30 Physical Examination z Classic presentation of myocardial infarction: ¾ z Other signs and symptoms ¾ ¾ ¾ ¾ ¾ z Pain or discomfort under sternum for longer than 15 min Apprehension Diaphoresis Dyspnea Nausea and vomiting Sense of impending doom Atypical presentations Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Initial Assessment z Level of consciousness z Respirations z Pulse (rate, regularity) z Blood pressure z Skin Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Physical Examination z “LookLook-listenlisten-feel” feel” approach Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 31 Look z Skin color, capillary refill, skin moisture ¾ ¾ z Oxygenation (pulse oximetry) Cardiac function (peripheral perfusion) Jugular vein distention (JVD) ¾ ¾ Evaluate with head elevated to 45 degrees Difficult to assess in obese patients Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Look z Peripheral and presacral edema BackBack-pressure in venous circulation Obvious in dependent areas ¾ Nonpitting • Minimal depression of tissue after removal of finger pressure ¾ Pitting • Depression of tissue remains after removal of finger ¾ ¾ pressure Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Look z Indicators of cardiac disease Nitroglycerin patch Midsternal scar from coronary surgery ¾ Implanted pacemaker or automatic implantable cardiovertercardioverter-defibrillator (left upper chest; abdominal wall) ¾ Medic alert information ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 32 Listen z Lung sounds ¾ ¾ z Equality Adventitious sounds • May indicate pulmonary congestion or edema Heart sounds ¾ Gallops Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Heart Sounds z Auscultate for: Frequency (pitch) Intensity (loudness) ¾ Duration ¾ Timing in the cardiac cycle ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Auscultating Heart Sounds Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 33 Point of Maximal Impulse (PMI) z Apical impulse ¾ ¾ z Visible and palpable Produced by contraction of left ventricle Pulse deficits noted by palpating or auscultating apical impulse and carotid pulse simultaneously Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Heart Sounds z Aortic ¾ z 2nd intercostal space to right of sternum Pulmonic ¾ 2nd intercostal space to left of sternum Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Heart Sounds z Tricuspid ¾ z 5th left intercostal space close to sternal border Mitral 5th intercostal space medial to left midclavicular line Over left ventricle ¾ Apical area or apex ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 34 S1 z “Lub” Lub” sound ¾ ¾ z Mitral and tricuspid valve closure Beginning of ventricular systole Diaphragm of stethoscope at apex of heart ¾ 5th intercostal space Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. S2 z “Dub” Dub” sound ¾ ¾ z Aortic and pulmonic valve closure End of ventricular systole Use diaphragm of stethoscope at 2nd intercostal space to right and left of the sternum ¾ Aortic and pulmonic areas Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. S3 z Extra heart sound ¾ Rapid ventricular filling z Common in children, athletes, and young adults z Abnormal in persons >30 y/o z Use bell of stethoscope at apex Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 35 S3 z Sounds like “KenKen-TuckTuck-Y” ¾ ¾ z Emphasis on “Tuck” Tuck” “Ken” Ken” = S1, “Tuck” Tuck” = S2, “Y” = S3 Warning sign of congestive heart failure Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. S4 Last of ventricular filling Tensing of atrioventricular valves Atrial contraction Just before S1 Heard at apex with stethoscope bell Sounds like “TenTen-nesnes-see” see” z z z z z z ¾ ¾ Emphasis on “Ten” Ten” “Ten” Ten” = S4, “Nes” Nes” = S1, “See” See” = S2 Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Feel z Peripheral or presacral edema z Pulse Rate Regularity ¾ Equality ¾ Pulse deficit ¾ Pulsus paradoxus ¾ Pulsus alternans ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 36 Feel z Skin Diaphoretic, pale skin • Peripheral vasoconstriction • Sympathetic stimulation ¾ Cyanosis • Poor oxygenation ¾ Fever • Infection ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. ECG Monitoring z Graphic representation of the heart's electrical activity z Generated by depolarization and repolarization of atria and ventricles Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. ECG Monitoring z Tool to identify cardiac abnormalities: Abnormal heart rates and rhythms Abnormal conduction pathways ¾ Hypertrophy or atrophy of portions of the heart ¾ Location of ischemic or infarcted cardiac muscle ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 37 ECG Monitoring z ECG tracing shows the heart's electrical activity z Does not provide information regarding mechanical events (e.g., force of contraction or blood pressure) Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. ECG Monitoring z Sum of action potentials in heart during cardiac cycle measured on body surface Obtained by applying electrodes to skin and connecting them to an ECG machine ¾ Voltage changes fed to machine • Amplified and displayed on screen • Printed on ECG paper ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Voltage z Positive ¾ z Negative ¾ z Upward deflection on ECG tracing Downward deflection on ECG tracing Isoelectric ¾ ¾ Straight baseline on ECG No current detected Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 38 ECG Leads z Two surface electrodes of opposite polarity Bipolar lead • Two electrodes of opposite polarity ¾ Unipolar lead • Single positive electrode and reference point ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Leads z Bipolar leads ¾ ¾ z Limb leads I, II, III Unipolar leads ¾ Augmented limb leads ¾ Precordial leads • aVR, aVL, and aVF • V1 through V6 z Each lead assesses electrical activity from a different angle Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Lead Comparison I, II, III Limb lead Bipolar aVR, aVL, aVF Limb lead Unipolar V1-V6 Chest lead Unipolar Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 39 Leads and Cardiac Surfaces Lead Cardiac Surface Viewed II, III, aVF Inferior wall V1, V2 Septum V3, V4 Anterior wall V5, V6, I, aVL Lateral wall Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Waveforms z Leads produce different ECG tracings: If depolarization moves toward a positive electrode, ECG shows an upward deflection ¾ If the wave moves away from a positive electrode, a negative deflection appears on the ECG ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Rule of Electrical Flow Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 40 Standard Limb Leads z Record difference in electrical potential between left arm, right arm, and left leg electrodes z Represent axes Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Axis z Average direction of the heart’ heart’s electrical activity z Triaxial reference system Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Axis z Lead I is a lateral (leftward) lead ¾ Assesses electrical activity from a viewpoint defined as 0° 0° on a circle divided into an upper negative 180° 180° and a lower positive 180° 180° Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 41 Axis Leads II and III are inferior leads z ¾ Assess the heart's electrical activity from vantage points of +60° +60° and +120° +120° Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Bipolar Lead Placement Limb lead placement Lead Positive Electrode Negative Electrode I Left arm Right arm II Left leg Right arm III Left leg Left arm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Augmented Limb Leads z Same electrodes as limb leads z Record difference in electrical potential between extremity lead sites and a reference point ¾ ¾ Zero electrical potential At center of the heart’ heart’s electrical field Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 42 Augmented Limb Leads Axis of each lead is formed by line from electrode site to center of the heart z Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Augmented Limb Leads z aVR, aVL, and aVF leads intersect at angles different from those of the standard limb leads z Produce three other intersecting lines of reference ¾ With standard limb leads, these leads make up a hexaxial reference system Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Lead aVR z Distant recording electrode z Looks at heart from right shoulder Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 43 Lead aVL z Lateral lead z Records electrical activity from left shoulder ¾ -30° 30° Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Lead aVF z Inferior lead z Records electrical activity from left lower extremity ¾ +90° +90° Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Limb Leads z Leads II, III, aVF ¾ z Inferior leads I, aVL ¾ Lateral leads Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 44 Modified Lead Recording z Limb lead placement altered to mimic precordial leads (V1 through V6) ¾ ¾ z Modified chest leads MCL1 to MCL6 May help: Distinguish between supraventricular tachycardia with aberration and ventricular tachycardia ¾ Diagnose bundle branch blocks ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. MCL1 z Positive electrode in V1 position ¾ z 4th intercostal space, right of sternum Negative electrode placed anteriorly ¾ Below lateral end of left clavicle Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. MCL6 z Positive electrode on left midaxillary line at 5th intercostal space ¾ z As for lead V6 Negative electrode placed anteriorly, below left shoulder Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 45 Routine ECG Monitoring z Usually lead II or MCL1 ¾ ¾ Best leads to visualize P waves Monitor for dysrhythmias Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. SingleSingle-Lead ECG Monitoring z Information gathered Heart rate Regularity ¾ Length of conduction in areas of the heart ¾ ¾ z Limitations ¾ May fail to reveal abnormalities • Particularly ST segment changes that signal myocardial injury or infarction Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 1212-Lead ECG Monitoring z 10 electrodes Four limb leads (right arm, right leg, left arm, left leg) • Leads I, II, and III, and aVF, aVL, and aVR ¾ Six chest leads • V1 through V6 ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 46 1212-Lead ECG Monitoring z Leads view left ventricle from position of its positive electrode Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 1212-Lead ECG Monitoring Identifies ST segment and TT-wave changes z ¾ Myocardial ischemia, injury, and infarction z Identifies VT in widewide-complex tachycardia z Determines electrical axis ¾ Presence of fascicular blocks Determines presence and location of bundle branch blocks z Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Precordial Leads z Six precordial leads are projected through anterior chest wall toward back z Positive leads are placed on chest in reference to thoracic landmarks ¾ Record electrical activity in transverse or horizontal plane Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 47 Precordial Leads z V1 and V2: Septal leads z V3 and V4: Anterior leads z V4 through V6: Lateral leads Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Application of Monitoring Electrodes z Electrodes are applied to chest wall z When applying electrodes: ¾ ¾ Cleanse area to remove moisture and dirt Use inner surfaces of arms and legs Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Application of Monitoring Electrodes z When applying electrodes: Trim excess body hair (if needed) Attach ECG cables to electrodes ¾ Attach electrodes ¾ Turn on ECG monitor ¾ Obtain baseline tracing ¾ Record tracing at significant events ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 48 Monitoring Electrodes z If poor signal, recheck cable connections and electrode contact z Other causes of poor signal Excessive body hair Dried conductive gel ¾ Poor electrode placement ¾ Diaphoresis ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 1212-Lead Electrode Application Locate the jugular notch Palpate for the angle of Louis ... Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 1212-Lead Electrode Application Follow the angle of Louis to patient’s right until it articulates with 2nd rib Locate the 2nd IC space (immediately below 2nd rib) Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 49 1212-Lead Electrode Application From the 2nd IC space, the 3rd and 4th IC spaces can be found V1 is positioned in the 4th IC space just right of the sternum Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 1212-Lead Electrode Application From V1, find the corresponding IC space on the left side of the sternum Place V2 electrode in the 4th IC space just left of sternum Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 1212-Lead Electrode Application From V2 position, locate 5th IC space, follow to the midclavicular line Position V4 electrode in 5th IC space in midclavicular line Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 50 1212-Lead Electrode Application Position V3 halfway between V2 & V4 V5 is positioned in anterior axillary line, level with V4 Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 1212-Lead Electrode Application Position V6 in the midaxillary line, level with V4 Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 1212-Lead Electrode Application Video Clip: Placement of 12-lead ECG Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 51 9-Lead from a 33-Lead z Obtain 99-lead reading from 33-lead monitor z Enable diagnostic setting (if available) z Run leads I, II, and III ¾ Obtain a strip of each lead and label Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 9-Lead from a 33-Lead z Leave monitor in lead III ¾ Negative electrode at left shoulder z Move left leg cable to each of MCL positions (from V1 to V6) to obtain a readout z Label each strip Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 9-Lead ECG Readout Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 52 ECG Graph Paper z Standardized to allow ECG analysis z Squares 1 mm in height and width Darker lines every fifth square, vertically and horizontally ¾ Large square is 5 mm high and 5 mm wide ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. ECG Graph Paper z As paper moves past stylus of ECG machine, it measures time and amplitude z Time measured on horizontal plane ¾ z Side to side ECG recorded at standard speed of 25 mm/sec: ¾ ¾ Each small square equals 1 mm (0.04 second) Each large square equals 5 mm (0.20 second) Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. ECG Graph Paper z Amplitude measured on vertical axis (top to bottom) of graph paper z Each small square of graph paper = 0.1 mV z Each large square (five small squares) = 0.5 mV Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 53 ECG Graph Paper Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Calibration z Sensitivity of 1212-lead ECG machine is standardized z When calibrated, a 1 mV electrical signal produces a 10 mm deflection (2 large squares) on ECG tracing Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Time Interval Markings z Denoted by short vertical lines on ECG graph paper z At standard speed, the distance between each short vertical line is 75 mm (3 sec) Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 54 Relationship of ECG to Electrical Activity z z Each waveform represents conduction of an electrical impulse through a specific part of the heart Waveforms begin and end at isoelectric line ¾ Isoelectric line shows absence of electrical activity in cardiac tissue Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Relationship of ECG to Electrical Activity z Deflections above baseline— baseline—positive z Deflections below baseline— baseline—negative ¾ ¾ Electrical flow toward positive electrode Electrical flow away from positive electrode Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Relationship of ECG to Electrical Activity z Normal ECG consists of a P wave, a QRS complex, and a T wave z Also evaluate: ¾ ¾ ¾ z PR interval ST segment QT interval Combination of these waves represents a single heartbeat ¾ One complete cardiac cycle Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 55 P Wave z First positive (upward) deflection on ECG z Atrial depolarization z Rounded and precedes QRS complex ¾ ¾ Begins with first positive deflection from baseline Ends when wave returns to baseline Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. P Wave z z z Duration normally <0.10 sec Amplitude normally 0.50.5-2.5 mm Followed by QRS complex unless conduction disturbances Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. PR Interval z Time it takes for electrical impulse to be conducted through atria and AV node up to ventricular depolarization ¾ ¾ Measured from beginning of P wave to beginning of next deflection on baseline 0.120.12-0.20 sec Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 56 PR Interval Normal PR interval indicates electrical impulse conducted through atria and AV node, normally and without delay z Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. QRS Complex z Three individual waves ¾ ¾ ¾ Q R S z Begins where first wave of complex deviates from baseline z Ends where last wave of complex begins to flatten at, above, or below baseline Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. QRS Complex z Direction of QRS complex may be: Predominantly positive • Upright ¾ Predominantly negative • Inverted ¾ Biphasic • Partly positive, partly ¾ negative Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 57 QRS Complex z Normal QRS complex is narrow and sharply pointed z Duration ¾ z <0.080.08-0.10 sec Amplitude ¾ <5 mm to >15 mm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Q Wave z First negative (downward) deflection of QRS complex on ECG ¾ z May not be present in all leads Depolarization of interventricular septum Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. R Wave z First positive deflection after the P wave ¾ Subsequent positive deflections in the QRS complex that extend above the baseline and that are taller than the first R wave are called R prime (R’ ), etc. (R’), R double prime (R’’ (R’’), Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 58 S Wave z Negative deflection after R wave ¾ ¾ Subsequent negative deflections are called S prime (S’ (S’), S double prime (S” (S”) R and S waves are electrical forces from depolarization of right and left ventricles Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. QRS Complex z Follows P wave z Approximate beginning of mechanical systole of ventricles ¾ z Continues through onset of T wave Ventricular depolarization ¾ Conduction of electrical impulse from AV node through bundle of His, Purkinje fibers, and right and left bundle branches Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. QRS Complex Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 59 ST Segment z Early phase of repolarization of ventricles z Follows QRS complex z Ends with onset of T wave Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. ST Segment z ST segment “takes off” off” from the QRS complex at J point Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. ST Segment z Position of ST segment is commonly judged using baseline of PR or TP interval for reference ¾ ¾ ST segment elevation ST segment depression Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 60 ST Segment z Abnormal ST segments Infarction Ischemia ¾ Pericarditis ¾ After digitalis administration ¾ Other disease states ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. T Wave z Repolarization of ventricular cells z Last part of ventricular systole z Above or below isoelectric line z Usually rounded and slightly asymmetrical Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. T Wave z Deep, symmetrically inverted T waves may suggest cardiac ischemia z T wave elevated more than half the height of the QRS complex may indicate: ¾ ¾ Onset of myocardial ischemia Hyperkalemia Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 61 QT Interval Onset of the QRS complex until end of T wave z Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Artifact z Deflections on ECG produced by factors other than the heart's electrical activity z Causes Improper grounding of ECG machine Patient movement ¾ Loss of electrode contact with skin ¾ Patient shivering or tremors ¾ External chest compressions ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Artifact— Artifact—Muscle Tremors Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 62 Artifact— Artifact—Loose Electrode Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Artifact— Artifact—Biotelemetry Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Rhythm Analysis z To determine if potential for lifelife-threatening rhythm disturbances, ask: Is the patient sick? What is the heart rate? ¾ Are there normalnormal-looking QRS complexes? ¾ Are there normalnormal-looking P waves? ¾ What is the relationship between P waves and QRS complexes? ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 63 Step 1: Analyze the QRS Complex z z Analyze for regularity and width Supraventricular QRS complexes are <0.10 sec wide Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Normal QRS Complexes Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Step 1: Analyze the QRS Complex z Complexes >0.12 sec wide indicate: ¾ ¾ Conduction abnormality in ventricles Focus that originates in ventricles and is abnormal Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 64 Analyzing the QRS Complex z To evaluate abnormal QRS width, identify lead with widest QRS complex ¾ Part of QRS complex may be blended with baseline in some leads Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Abnormal QRS Complexes Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Abnormal QRS Complexes Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 65 Abnormal QRS Complexes Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Step 2: Analyze the P Waves z Present? z Regular? z One P wave for each QRS complex, and a QRS complex follows each P wave? z Upright or inverted? z All alike? Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Normal P Waves Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 66 Step 3: Analyze the Rate z Rate <60 = Bradycardia z Rate >100 = Tachycardia Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Heart Rate Rulers z Various manufacturers z Accurate if rhythm is regular ¾ May not be readily available Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Heart Rate Calculator Ruler Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 67 Triplicate Method z Memorize two sets of numbers: 300300-150150-100 and 75756060-50 ¾ Accurate only if rhythm is regular and >50 bpm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. R-R Method 1 z z Measure distance in seconds between peaks of two consecutive R waves Divide this into 60 to obtain heart rate Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. R-R Method 2 z z Count large squares between peaks of two consecutive R waves Divide into 300 to obtain heart rate Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 68 R-R Method 3 z z Count small squares between peaks of two consecutive R waves Divide into 1500 to obtain heart rate Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 6-Second Method z Least accurate method z Count number of QRS complexes in 66-sec interval and multiply number by 10 ¾ Quickly obtain rate in regular and irregular rhythms Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Step 4: Analyze the Rhythm z To analyze rhythm, compare RR-R intervals from left to right, z If distances between R waves are equal or vary by <0.16 sec, rhythm is regular z If shortest and longest RR-R intervals vary by >0.16 sec, rhythm is irregular Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 69 Determining the Rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Regular Rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Step 4: Analyze the Rhythm z Regularly irregular rhythm ¾ Patterned irregularity or group beating Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 70 Step 4: Analyze the Rhythm Occasionally irregular z ¾ Only one or two RR-R intervals are unequal to the others Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Step 4: Analyze the Rhythm Irregularly irregular z ¾ Totally irregular; no relationship between RR-R intervals Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Step 5: Analyze the PR Interval z Time it takes for electrical impulse to be conducted through atria and AV node z Should be constant across ECG tracing Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 71 Step 5: Analyze the PR Interval z Prolonged PR interval Delay in impulse conduction through AV node or bundle of His ¾ AV block ¾ z Short PR interval ¾ Impulse progressed from atria to ventricles through pathways other than AV node Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Normal PR Intervals Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Normal PR Intervals Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 72 Abnormal PR Intervals Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Abnormal PR Intervals Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Causes of Cardiac Dysrhythmias z z z z Myocardial ischemia Autonomic nervous system imbalance Distention of heart chambers AcidAcid-base abnormalities z z z z z z Hypoxemia Electrolyte imbalance Drug effects or toxicity Electrical injury Hypothermia CNS injury Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 73 Classification of Dysrhythmias z Based on a number of factors Changes in automaticity versus disturbances in conduction ¾ Cardiac arrest (lethal) rhythms and noncardiac arrest (nonlethal) rhythms ¾ Site of origin ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Dysrhythmias Originating in the SA Node z Sinus bradycardia z Sinus tachycardia z Sinus dysrhythmia z Sinus arrest Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Dysrhythmias Originating in the Atria z Wandering pacemaker z Premature atrial complex (PAC) z Paroxysmal supraventricular tachycardia (PSVT) z Atrial flutter z Atrial fibrillation Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 74 Dysrhythmias Originating in the AV Node z Premature junctional complex (PJC) z Junctional escape complexes or rhythms z Accelerated junctional rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Dysrhythmias Originating in the Ventricles z z z z z z Ventricular escape complexes or rhythm Premature ventricular complex (PVC) Ventricular tachycardia (VT) Ventricular fibrillation (VF) Asystole Artificial pacemaker rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Disorders of Conduction z AV blocks ¾ ¾ ¾ ¾ FirstFirst-degree AV block SecondSecond-degree AV block type I SecondSecond-degree AV block type II ThirdThird-degree AV block z Disturbances of ventricular conduction z Pulseless electrical activity (PEA) z Preexcitation syndrome: WolffWolff-ParkinsonParkinson-White (WPW) syndrome Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 75 Treatment Guidelines z Treat patient, not monitor z Algorithms presume condition persists, ¾ z In cardiac arrest CPR is always performed Apply different interventions if indications exist Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Treatment Guidelines z Airway, ventilation, oxygenation, chest compression, and defibrillation z Take precedence over initiating an IV line or administering drugs Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Treatment Guidelines z Some medications can be administered via endotracheal tube ¾ z Use endotracheal dose 22-2½ times IV dose for adults In arrest, with few exceptions IV meds are administered rapidly by bolus method ¾ Follow with a 2020-30 mL bolus of IV fluid and immediately elevate extremity Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 76 Dysrhythmias Originating in the SA Node Sinus dysrhythmias z ¾ Often from increases or decreases in vagal tone SA node gets inhibitory parasympathetic impulses from vagus nerve to keep rate below discharge rate of pacemaker cells z ¾ ¾ If vagal discharge increases, heart rate becomes bradycardic If vagal discharge decreases, sympathetic stimulation results in sinus tachycardia Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Dysrhythmias Originating in the SA Node z SA node dysrhythmias Normal duration of QRS complex • If no bundle branch block ¾ Upright P waves in lead II ¾ P waves similar ¾ Normal duration of PR interval • If no AV block ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Sinus Rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 77 Sinus Bradycardia z Slowing of pacemaker rate of SA node z Causes ¾ ¾ ¾ ¾ ¾ ¾ ¾ Adult HR <60 bpm Sinus node disease Increased vagal tone Hypoxia Hypothermia Drugs AMI Can decrease cardiac output and cause: z ¾ ¾ ¾ Hypotension Syncope Angina Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Sinus Bradycardia Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Sinus Bradycardia— Bradycardia—Management z Observe, if patient clinically stable z If unstable, treatment may include: Oxygen Atropine ¾ Dopamine infusion ¾ Epinephrine infusion ¾ Transcutaneous pacing ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 78 Sinus Tachycardia z Increase in rate of sinus node discharge ¾ Adult HR >100 bpm z Causes ¾ ¾ ¾ z Treat underlying cause ¾ ¾ ¾ ¾ Exercise Fever Ingestion of drugs Smoking Hypovolemia Anemia Congestive heart failure Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Sinus Tachycardia Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Sinus Dysrhythmia z Difference between the longest and shortest R-R intervals is >0.16 sec z Often normal z Occurs in heart disease, drug treatment z No clinical management needed Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 79 Sinus Dysrhythmia Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Sinus Arrest z Marked depression in SA node automaticity z Causes ¾ ¾ z Sinus node fails, causes periods of cardiac standstill until: ¾ ¾ Other pacemakers discharge Sinus node resumes normal function ¾ ¾ ¾ ¾ Increased vagal tone Hypoxia Ischemia Excess digitalis or propranolol Hyperkalemia Damaged SA node Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Sinus Arrest z z z z z May cause decreased cardiac output Syncope Asystole possible Observe If symptomatic: ¾ ¾ Atropine TCP Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 80 Sinus Arrest Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Dysrhythmias Originating in the Atria z Originate in tissues of atria or internodal pathways z Causes of atrial dysrhythmias Ischemia Hypoxia ¾ Atrial dilation caused by: • Congestive heart failure • Mitral valve abnormalities • Increased pulmonary artery pressures ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Dysrhythmias Originating in the Atria z ECG features common to atrial dysrhythmias (if no ventricular conduction disturbance): Normal QRS complexes P waves (if present) that differ in appearance from sinus P waves ¾ Abnormal, shortened, or prolonged PR intervals ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 81 Wandering Atrial Pacemaker z Transfer of pacemaker sites from sinus node to other pacemaker in atria or AV junction z Shift in site is usually transient z May be normal z Can result from digitalis toxicity z Not often clinically significant Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Wandering Atrial Pacemaker Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Multifocal Atrial Tachycardia z Variant of wandering atrial pacemaker ¾ Rates in the 120 to 150 per minute range z Common in severe COPD z Treat underlying disorder z ECG characteristics z Clinical significance z Management Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 82 Premature Atrial Complex z Single impulse originating in atria ¾ Outside sinus node z Single ectopic pacemaker site or multiple sites in atria z Enhanced automaticity or reentry mechanism z Isolated PACs not significant z Multiple PACs may predispose to SVT Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Premature Atrial Complex z Causes ¾ ¾ ¾ ¾ ¾ ¾ z Increased sympathetic tone Stimulant use Drugs Electrolyte imbalance Hypoxia Cardiac disease Treatment ¾ ¾ Observation If not conducted: • May need bradycardia treatment Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. PACs Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 83 SVT and PSVT z Supraventricular tachycardias (SVTs) Paroxysmal supraventricular tachycardia (PSVT) Nonparoxysmal atrial tachycardia ¾ Multifocal atrial tachycardia ¾ Junctional tachycardia ¾ Atrial flutter ¾ Atrial fibrillation ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. SVT and PSVT z PSVT ¾ z Atrial origin ¾ z Paroxysmal atrial tachycardia (PAT) AV junction ¾ z Supraventricular tachycardia that begins abruptly Paroxysmal junctional tachycardia (PJT) Rapid atrial or junctional depolarization overrides SA node Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. SVT and PSVT z Often reentry mechanism z Stress, overexertion, tobacco, caffeine z WolffWolff-ParkinsonParkinson-White syndrome z May be tolerated briefly if healthy z Can cause: ¾ ¾ ¾ Compromised cardiac output Hypotension syncope CHF Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 84 SVT and PSVT— PSVT—Treatment z Stable z Unstable ¾ Vagal maneuvers ¾ Adenosine ¾ Calcium Channel Blockers or ¾ Beta blockers ¾ Synchronized cardioversion • 50 J (PSVT or Atrial Flutter) • 100 J • 200 J • 300 J • 360 J h Or equivalent biphasic Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. PSVT Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Atrial Flutter z Usually rapid atrial reentry focus z Associated with: ¾ ¾ z Conduction variable z Sawtooth or picketpicketfence appearance ¾ ¾ ¾ z Loss of atrial kick z May decrease perfusion ¾ ¾ Cardiomyopathy Cardiac hypertrophy Digitalis toxicity Hypoxia CHF Pericarditis Myocarditis Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 85 Atrial Flutter Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Atrial Fibrillation z Multiple areas of reentry in atria or ectopic atrial pacemakers z Chaotic impulses too numerous to be conducted by AV node through ventricles AV conduction is random Ventricular response irregular ¾ Usually rapid unless patient is on medication to slow ventricular rate ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Atrial Fibrillation z P waves absent z F waves z Causes ¾ ¾ ¾ ¾ z Atrial kick lost z More unstable with rapid ventricular response z Cardiac decompensation ¾ “Holiday heart” heart” syndrome Rheumatic heart disease CHF Cardiac disease Chest trauma Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 86 Atrial Fibrillation Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. A-Fib & AA-Flutter Management Management based on: z ¾ ¾ ¾ Time of rhythm onset Signs and symptoms Heart function Rate control with: z ¾ ¾ ¾ Diltiazem Beta blockers Magnesium z Unstable ¾ Synchronized cardioversion • 50 J (Atrial Flutter) • 100 J • 200 J • 300 J • 360 J h Or equivalent biphasic Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Atrial Fibrillation and WolffWolffParkinson White Syndrome z Do not administer: Adenosine Diltiazem or verapamil ¾ Beta blockers ¾ Digoxin ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 87 Dysrhythmias of the AV Junction z If SA node and atria don’ don’t generate electrical impulses, AV node or area surrounding it may assume role of secondary pacemaker Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Dysrhythmias of the AV Junction z May occur because of: Hypoxia Ischemia ¾ Myocardial infarction ¾ Drug toxicity ¾ ¾ z Usually benign arrhythmia z Assess to determine patient's response to rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Premature Junctional Complex z Single electrical impulse z Originates in AV junction z Occurs before next expected sinus impulse z P waves occur before, during, or after QRS z Abnormal P wave z PRI <0.12 sec Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 88 Premature Junctional Complex z Usually no clinical significance z Causes ¾ ¾ z No treatment needed ¾ ¾ ¾ Medications Increased vagal tone Hypoxia Congestive heart failure AV junction damaged Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. PJCs Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Junctional Escape Complex or Rhythm z Isolated impulse or rhythm z Rate of primary pacemaker falls below AV junction or with SA or AV block z P waves may be absent z If present before, during, or after QRS z PRI <0.16 sec z Rate: 4040-60/min Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 89 Junctional Escape Complex or Rhythm z Decreased cardiac output ¾ z Causes ¾ ¾ ¾ Increased vagal tone Slowed SA discharge AV block Stable ¾ z Usually rates below 50/min z Observe Unstable ¾ Treat as bradycardia Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Junctional Escape Complex or Rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Accelerated Junctional Rhythm z Increased AV junction automaticity z Discharges faster than intrinsic rate ¾ 4040-60 bpm z Overrides SA node z Rate: 6060-99 bpm z Usually stable z Observe Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 90 Accelerated Junctional Rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Dysrhythmias Originating in the Ventricles z Ventricular rhythms often life threatening z Failure of atria, AV junction z Enhanced automaticity z Reentry z Associated with myocardial ischemia or infarction z Least efficient pacemaker Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Dysrhythmias Originating in the Ventricles z QRS complexes >0.12 sec, bizarre appearance z P waves hidden or superimposed on QRS z ST deviated from baseline Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 91 Ventricular Escape Complexes or Rhythms z Isolated impulse or rhythm z Idioventricular rhythm z Impulses from higher pacemakers ¾ ¾ ¾ z Fail Don’ Don’t reach ventricles Or rate of discharge of higher pacemakers is less than that of ventricles Compensatory mechanism ¾ Prevents cardiac standstill Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Ventricular Escape Complexes or Rhythms z z Hypotension Decreased ¾ ¾ z z z z z Cardiac output Perfusion to brain z Management ¾ ¾ ¾ Oxygen TCP Dopamine Syncope Shock Absent P waves Rate 2020-40 bpm Wide QRS Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Ventricular Escape Rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 92 “Dying Heart” Heart” or Agonal Rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Premature Ventricular Complexes z Single ectopic impulse z From irritable focus in ventricle z Earlier than expected sinus beat z Common z Occurs with any cardiac rhythm z Enhanced automaticity or a reentry mechanism Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. PVCs Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 93 Compensatory Pause z Measure interval between R wave before PVC and R wave after PVC z If compensatory, distance equals twice RR-R interval of underlying rhythm z Interpolated PVC ¾ ¾ PVC falls between two sinus beats Doesn’ Doesn’t interrupt rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Interpolated PVC Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Unifocal and Multifocal PVCs z Unifocal PVCs ¾ ¾ z Originate from single site within ventricles Look alike Multifocal PVCs ¾ ¾ Originate from different ventricular sites Varying shapes and sizes Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 94 Unifocal and Multifocal PVCs Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Fusion Beats z PVCs occur at same time as ventricular activation by underlying rhythm ¾ z Can cause ventricular depolarization simultaneously in two directions Fusion beat QRS complex has characteristics of PVC and QRS complex of underlying rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Fusion Beat with PVC Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 95 Grouped Beating z PVCs in patterns of grouped beating Bigeminy • Every other complex is PVC ¾ Trigeminy • Every 3rd complex is PVC ¾ Quadrigeminy • Every 4th complex is PVC ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Ventricular Bigeminy and Trigeminy Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. PVCs z PVCs not separated by complex of underlying rhythm z Couplets ¾ z Run of VT ¾ ¾ z Two PVCs in a row >3 sequential PVCs Rate: >100 bpm R-onon-T phenomenon Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 96 R-onon-T Phenomenon Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. PVCs— PVCs—Causes Healthy individuals z ¾ Usually no significance Pathological PVCs z ¾ ¾ ¾ ¾ ¾ ¾ ¾ Myocardial ischemia Hypoxia Electrolyte imbalance Congestive heart failure Increased sympathetic tone Stimulants Drugs Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. PVCs z QRS >0.12 sec z P waves present or absent ¾ z No relationship to QRS Significant if: Frequent Multifocal ¾ R-onon-T ¾ Grouped beats ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 97 PVCs z Management, if clinically significant: Oxygen Antiarrhythmic drugs ¾ Check potassium at hospital • Treat hypokalemia if present ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Ventricular Tachycardia z >3 consecutive ventricular complexes z Rate: >100 bpm z Overrides primary pacemaker z Starts suddenly, triggered by a PVC z Atria and ventricles are asynchronous z If sustained, may lead to unconsciousness and loss of pulse Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Monomorphic Ventricular Tachycardia z z z z z z z Cardiac disease Electrolyte imbalances CHF Increased catecholamines Stimulants Drugs Long QT interval z Stable but symptomatic: ¾ ¾ ¾ Oxygen Amiodarone Procainamide z Unstable z Pulseless ¾ ¾ Cardioversion Treat as ventricular fibrillation Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 98 Monomorphic VT Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Torsades de Pointes z Prolonged QT interval ¾ z Treatment varies: ¾ May or may not be present ¾ ¾ z Idiopathic z Drug induced z Polymorphic VT ¾ ¾ z DC drugs that prolong QT Magnesium sulfate Lidocaine Isoproterenol Overdrive pacing If Unstable: ¾ Unsynchronized cardioversion Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Torsades de Pointes Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 99 1212-Lead Strategies for WideWide-Complex Tachycardias z Determine axis deviation: ¾ ¾ Leads I, II, III, MCL1 (V1), MCL6 (V6) QRS complex negative in leads I, II, and III (extreme right axis deviation, or “no man’ man’s land” land”) and positive in MCL1 (V1) indicates VT • If not, proceed to step 2 Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Criteria for VT Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 1212-Lead Strategies for WideWide-Complex Tachycardias z If extreme right axis deviation is not present, assess QRS deflection in MCL1 (V1) and MCL6 (V6): Negative QS complex Negative RS complex ¾ Wide Q wave in MCL6 (V6) indicates VT ¾ ¾ z Regardless of the QRS deflection in leads I, II, and III Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 100 1212-Lead Strategies for WideWide-Complex Tachycardias z VT if positive QRS deflections with either: Single peak Taller left “rabbit ear” ear” ¾ RS complex with a fat R wave ¾ Slurred S wave in MCL1 (V1) ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Note “Rabbit Ear” Ear” Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 1212-Lead Strategies for WideWide-Complex Tachycardias z The presence of right axis deviation (negative QRS complex in lead I; positive QRS complex in leads II and III) and a negative QRS complex in MCL1 (V1) indicates VT Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 101 Right Axis Deviation and a Downward MCL1 Indicates VT Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 1212-Lead Strategies for WideWide-Complex Tachycardias z VT if: ¾ All precordial leads (V leads) are either positive or negative • Precordial concordance Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. VTVT-Concordance Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 102 1212-Lead Strategies for WideWide-Complex Tachycardias z RS interval >0.10 sec in any V lead indicates VT z Increased ventricular activation time Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. VT (RS interval is 0.16 sec) Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Ventricular Fibrillation z Chaotic ventricular rhythm z Quivering ventricular movements z No pulse z Multiple reentry foci in ventricles Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 103 Ventricular Fibrillation— Fibrillation—Causes z Myocardial ischemia z Acidosis z AMI z Electrolyte imbalance z ThirdThird-degree AV block z Electrical injury z Cardiomyopathy z Drug toxicity z Digitalis toxicity z Hypoxia Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Ventricular Fibrillation— Fibrillation—Treatment z If unwitnessed ¾ z z CPR first then: Epinephrine ¾ May substitute vasopressin for first or second dose Defibrillation z z Intubation z Vascular access Amiodarone ¾ z Lidocaine as alternative Effective CPR Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Ventricular Fibrillation Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 104 Coarse and Fine VF Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Ventricular Asystole z Absence of ventricular activity z Confirm in two leads z Primary event or follows other dysrhythmias z No cardiac output z Terminal rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Ventricular Asystole— Asystole—Treatment z Effective CPR z Intubation/IV z Epinephrine z Atropine z Consider and treat other causes ¾ Sodium bicarbonate possible Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 105 Ventricular Asystole Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Artificial Pacemaker Rhythms z Generate rhythm by electrical stimulation through electrode in the heart Fixed rate or asynchronous Demand pacemakers ¾ Atrial synchronous ventricular pacemakers ¾ AV sequential pacemakers ¾ RateRate-responsive pacemakers ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Artificial Pacemaker Rhythms Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 106 Causes of Pacemaker Malfunction z Battery failure z Runaway pacemaker z Failure of sensing device in demand pacemaker z Failure to capture Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Management of Pacemaker Failure z z z z True emergency Immediate recognition Rapid transport Principles to follow: Look for battery packs under skin/medical ID tag Follow appropriate algorithm ¾ Manage ventricular irritability ¾ Defibrillate if needed; do not discharge energy directly over battery pack ¾ Use TCP if indicated ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Heart Blocks z Delays or complete interruptions in cardiac electrical conduction z Occur in atria, between SA node and AV node, or in ventricles between AV node and Purkinje fibers z Caused by: ¾ ¾ Pathology in conduction system Physiological block Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 107 Heart Blocks— Blocks—Causes z AV junctional ischemia z AV junctional necrosis z Degenerative disease of conduction system z Electrolyte imbalances z Drug toxicity ¾ Often digitalis Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Heart Blocks— Blocks—Classification z Classified by: Site of block • (e.g., left bundle branch block) ¾ Degree of block • (e.g., secondsecond-degree AV block) ¾ Category of AV conduction disturbances • (e.g., Type I) ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. FirstFirst-Degree AV Block z Not true block z Delay in conduction ¾ Usually at AV node z Superimposed on another rhythm z Identify underlying rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 108 FirstFirst-Degree AV Block z PRI >0.20 sec z Usually transient z Often asymptomatic z May progress to other block z Observe Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. FirstFirst-Degree AV Block Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. SecondSecond-Degree AV Block Type I (Wenckebach) z z z Intermittent AV node Conduction delay increases from beat to beat until conduction to ventricle is blocked ¾ ¾ z z PR intervals get progressively longer until a P wave occurs that is not followed by QRS complex Pattern May be symptoms if rate is very slow Treat for bradycardia if symptomatic Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 109 SecondSecond-Degree AV Block Type I Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. SecondSecond-Degree AV Block Type II z Intermittent block z Atrial impulses are not conducted to ventricles z P waves conducted with a constant PR interval before a dropped beat Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. SecondSecond-Degree AV Block Type II z Usually a regular sequence with conduction ratios (P waves to QRS complexes) ¾ 2:1, 3:2, and 4:3 Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 110 SecondSecond-Degree AV Block Type II Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 3:2 AV Block and 4:3 AV Block Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. SecondSecond-Degree AV Block Type II z Below bundle of His z Two consecutive impulses (atrial P waves) fail to be conducted to ventricles z HighHigh-grade AV block Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 111 3:1 HighHigh-Grade AV Block Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. SecondSecond-Degree AV Block Type II z HighHigh-grade AV blocks have underlying atrial and ventricular rates z Slow rates and hypoperfusion z May advance to complete heart block z Treat symptomatic patients with TCP Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. ThirdThird-Degree Heart Block z Complete electrical block at or below the AV node ¾ Infranodal z SA node paces atria, and an ectopic focus paces ventricles z P waves and QRS complexes occur rhythmically, but the rhythms are unrelated to each other ¾ AV dissociation Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 112 ThirdThird-Degree AV Block z Causes ¾ ¾ ¾ ¾ ¾ z Increased vagal tone Septal necrosis Myocarditis Drug toxicity Electrolyte imbalance Significance ¾ ¾ ¾ Bradycardia may be severe Cardiac output decreased Wide complex is ominous sign Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. ThirdThird-Degree AV Block— Block—Treatment z Transvenous pacer is needed z Initial prehospital care if symptomatic: TCP Dopamine ¾ Epinephrine ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. ThirdThird-Degree AV Block Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 113 Ventricular Conduction Disturbances z Bundle branch blocks or hemiblocks z Delay electrical transmission below bundle of His Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Bundle Branch Blocks and Hemiblocks z Common causes of bundle branch block Ischemic heart disease Acute heart failure ¾ Acute myocardial infarction ¾ Hyperkalemia ¾ Trauma ¾ Cardiomyopathy ¾ Aortic stenosis ¾ Infection ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Bundle Branch Anatomy z Bundle of His divides: Left and right bundle branches Right bundle branch continues toward apex and spreads through right ventricle ¾ Left bundle branch subdivides into anterior and posterior fascicles and spreads through left ventricle ¾ ¾ z Electrical impulse conduction through Purkinje fibers stimulates ventricular contraction Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 114 Bundle Branch Anatomy Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Bundle Branch Anatomy z Normal conduction Left side of septum is stimulated first Electrical impulse traverses septum to stimulate other side ¾ Left and right ventricles are then simultaneously stimulated ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Normal Ventricular Activation Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 115 Bundle Branch Block— Block—ECG z One ventricle depolarizes and contracts before the other z Ventricular activation is not simultaneous, therefore QRS complex widens ¾ z Slurred or notched appearance • “Rabbit ears” ears” QRS complex is >0.12 sec Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Bundle Branch Block z Criteria for bundle branch block ¾ ¾ QRS complex >0.12 sec QRS complexes produced by supraventricular activity Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Bundle Branch Block z Leads V1 and V6 ¾ ¾ z MCL1 and MCL6 Permit differentiation of right and left bundle branch blocks Normal conduction ¾ ¾ V1 (MCL1) is predominantly negative QRS complex is 0.080.08-0.10 sec Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 116 Right Bundle Branch Block z Left bundle branch performs normally z Activates left side of heart before right z ECG characteristics Initial negative deflection (S wave) RSRRSR-prime pattern ¾ QRS (or in this case, RSR) duration >0.12 sec ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Right Bundle Branch Block Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Left Bundle Branch Block z Fibers that fire interventricular septum are blocked: ¾ ¾ z Alters normal septal activation Sends it in opposite direction ECG characteristics Initial Q wave in V1 (MCL1) R wave in V1 (MCL1) ¾ Deep, wide S wave (QS pattern) ¾ QRS duration >0.12 sec ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 117 Left Bundle Branch Block Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Left vs. Right BBB z Find J point z Draw line back into QRS complex z Fill in triangle created z Note direction triangle points Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Anterior Hemiblock z More common than posterior hemiblock z Anterior fascicle of left bundle branch is a longer and thinner structure z Blood supply primarily from left anterior descending (LAD) coronary artery z Anterior hemiblock characterized by left axis deviation in patient with supraventricular rhythm Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 118 Anterior Hemiblock z Other ECG findings in anterior hemiblock: Normal QRS complex (<0.12 sec) or a right bundle branch block ¾ Small Q wave followed by tall R wave in lead I ¾ Small R wave followed by deep S wave in lead III ¾ z High risk to develop complete heart block Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Anterior Hemiblock Showing 1 Block of 3 Fascicles Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Posterior Hemiblock z Right axis deviation with normal QRS complex or right bundle branch block z Other ECG findings ¾ ¾ Small R wave followed by deep S wave in lead I Small Q wave followed by tall R wave in lead III Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 119 Posterior Hemiblock Showing 2 of 3 Fascicles Blocked Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Bifascicular Block z 2 of 3 pathways for ventricular conduction blocked Right bundle branch block with anterior or posterior hemiblock ¾ Left bundle branch block ¾ z Compromises myocardial contractility and cardiac output z May develop complete heart block suddenly Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Multilead Determination of Axis and Hemiblocks z Identifying axis can be useful in determining the presence of hemiblocks z Best evaluated by looking at the QRS complexes in leads I, II, and III Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 120 Multilead Determination of Axis and Hemiblocks z Axis is: Normal if QRS deflection is positive in bipolar leads Physiological left (normal in some patients) when QRS deflection is: • Positive in leads I and II • Negative (inverted) in lead III ¾ Pathological left when QRS deflection is: • Positive in lead I • Negative in leads II and III (indicating an anterior hemiblock) ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Multilead Determination of Axis and Hemiblocks z Right axis when QRS deflection is: ¾ ¾ ¾ z Negative in lead I, negative or positive in lead II Positive in lead III (pathological in any adult) Indicative of posterior hemiblock Extreme right (“ (“No man’ man’s land” land”) when QRS deflection is negative in all three leads ¾ Rhythm is ventricular in origin Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Pulseless Electrical Activity z Absence of detectable pulse and presence of rhythm other than VT or VF z Prognosis is poor unless underlying cause is identified and corrected z Priority of care is to maintain circulation with basic and advanced life support z Search for correctable cause Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 121 Pulseless Electrical Activity Correctable causes z ¾ ¾ ¾ ¾ ¾ ¾ ¾ Cardiac tamponade Tension pneumothorax Hypoxemia Acidosis Hyperkalemia Hypothermia Drug overdoses z Less correctable causes ¾ ¾ ¾ ¾ ¾ Massive myocardial damage Prolonged ischemia Profound hypovolemia Massive pulmonary embolism Profound shock Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Pulseless Electrical Activity z Management Effective CPR ALS ¾ Epinephrine ¾ Atropine if HR <60 bpm ¾ Identify and correct specific causes ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Various PEA Rhythms as Seen in Lead II Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 122 Preexcitation Syndromes z Clinical condition with abnormal conduction pathway between atria and ventricles Bypasses AV node and/or bundle of His Allows electrical impulses to depolarize ventricles earlier than usual ¾ Several accessory pathways ¾ ¾ z Most common preexcitation syndrome is WolffWolff-ParkinsonParkinson-White (WPW) syndrome Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. WolffWolff-ParkinsonParkinson-White Syndrome z Bundle of Kent connects lateral wall of atrium and ventricle ¾ Bypasses AV node z LifeLife-threatening if tachycardia develops z Rate: Normal unless associated with rapid supraventricular tachycardia z PR interval <0.12 sec ¾ Normal delay at AV node does not occur Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. WolffWolff-ParkinsonParkinson-White Syndrome z ECG findings ¾ ¾ ¾ Short PR interval Delta wave QRS widening z Susceptible to PSVTs z Amiodarone, procainamide z May be harmful: ¾ ¾ Adenosine, calcium channel blockers Beta blockers, digoxin Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 123 WPW (A) Appearance of WPW syndrome in leads where QRS complex is upright (B) Appearance of WPW syndrome with QRS complex predominantly negative Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Acute Coronary Syndromes z Acute myocardial infarction (AMI) Unstable angina (UA) z Treatment goals z Reduce myocardial necrosis Prevent major adverse cardiac events ¾ Treat acute complications of ACS ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Atherosclerosis z Progressive narrowing of lumen of medium and large arteries ¾ z Aorta and its branches, cerebral arteries, coronary arteries Development of thick, hard, atherosclerotic plaques called atheromas or atheromatous lesions ¾ Commonly found in areas of turbulent blood flow Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 124 Atherosclerosis— Atherosclerosis—Risk Factors z z z z z z z Age Earlier in men than women Family history Diabetes Smoking Hypertension Hypercholesterolemia Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Atherosclerosis— Atherosclerosis—Effects z Disrupts intimal surface, causing loss of vessel elasticity and increase in thrombogenesis ¾ ¾ Atheroma reduces diameter of vessel lumen Decreases blood supply to tissues Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Angina Pectoris z Symptom of myocardial ischemia z “Choking” Choking” pain in the chest z Imbalance between myocardial oxygen supply and demand z Accumulation of lactic acid and carbon dioxide in ischemic tissues of myocardium ¾ Metabolites irritate nerve endings and produce pain Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 125 Angina Pectoris z Causes ¾ ¾ Atherosclerotic disease of the coronary arteries Temporary occlusion due to coronary artery spasm with or without atherosclerosis • Prinzmetal's angina Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Angina Pectoris z Pain described as pressure, squeezing, heaviness, or tightness in chest ¾ ¾ z 30% feel pain only in chest Others describe as radiating to shoulders, arms, neck, and jaw and through to back Associated signs and symptoms ¾ ¾ ¾ ¾ Anxiety Shortness of breath Nausea or vomiting Diaphoresis Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Stable Angina z Usually caused by physical exertion or emotional stress z Pain lasts 11-5 min ¾ May last as long as 15 min z Relieved by rest, nitroglycerin, or oxygen z “Attacks” Attacks” are usually similar in nature z Always relieved by same therapy Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 126 Unstable Angina z Preinfarction angina z Anginal pattern that has changed in its ease of onset, frequency, intensity, duration, or quality z Includes “new onset” onset” anginal chest pain z May occur during exercise or at rest z Pain lasts >10 min z Less promptly relieved than stable angina Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Unstable Angina— Angina—Management z Place patient at rest z Administer oxygen z Administer aspirin (per protocol) z IV therapy z Pharmacological therapy ¾ Nitroglycerin ¾ Morphine z Monitor ECG z Transport as soon as possible Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Myocardial Infarction z Sudden and total occlusion or nearnear-occlusion of blood flowing through affected coronary artery z Ischemia, injury, and necrosis of myocardium distal to occlusion z Often associated with atherosclerotic heart disease (ASHD) z Precipitating events Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 127 Types and Locations of Infarcts z Infarction distal to occluded artery z Size of infarct determined by: Metabolic needs of tissue supplied by occluded vessel ¾ Collateral circulation ¾ Time until flow is reestablished ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Types and Locations of Infarcts z Emergency care Increasing oxygen supply Decreasing metabolic needs ¾ Providing collateral circulation ¾ Reestablishing perfusion to ischemic myocardium quickly ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Types and Locations of Infarcts z Most AMIs involve ventricle or interventricular septum, which is supplied by either of two major coronary arteries ¾ Some patients sustain damage to right ventricle Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 128 Types and Locations of Infarcts z Anterior, lateral, or septal wall infarction ¾ z Usually left coronary artery occlusion Inferior wall infarction ¾ Usually right coronary artery occlusion Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Myocardial Infarction z Three ischemic syndromes z Based on rupture of an unstable plaque in an epicardial artery Unstable angina NonNon-STST-elevation myocardial infarction ¾ STST-elevation myocardial infarction ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Infarction z Unstable angina Thrombus has not completely obstructed coronary flow ¾ Intermittent ischemic episode ¾ May lead to complete occlusion and AMI ¾ z NonNon-STST-elevation MI ¾ ¾ STST-segment depression T-wave abnormalities Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 129 Infarction z STST-elevation MI ¾ Q-wave MI • Pathological Q waves h h > 5 mm in depth > 0.04 sec in duration in >2 contiguous leads Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Death of Myocardium z After blood flow to myocardium stops, cells switch to anaerobic metabolism ¾ Produces ischemic pain (angina) z Cells begin to swell and depolarize z If collateral flow and reperfusion are inadequate, much of muscle dies distal to occlusion Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Area of Infarction Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 130 Myocardial Infarction— Infarction—Deaths z z z Lethal dysrhythmias • VT • VF • Cardiac standstill Pump failure • Cardiogenic shock • CHF Myocardial tissue rupture • Ventricle, septum, or papillary muscle Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. MI— MI—Signs and Symptoms Pain is similar to angina May radiate to arms, neck, jaw, or back Dyspnea Anxiety Agitation Sense of impending doom Nausea and vomiting Diaphoresis Cyanosis Palpitations z z z z z z z z z z Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. MI— MI—Signs and Symptoms z Chest pain often constant z Not altered by nitroglycerin or medications, rest, changes in body position, or breathing patterns ¾ ¾ Onset of pain at rest in >50% of MI patients Most have experienced warning anginal pain (preinfarction angina) hours or days before Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 131 Myocardial Infarction— Infarction—ECG Findings z Heart muscle unable to contract effectively z Remains in depolarized state ¾ Current flow between pathologically depolarized and normally repolarized areas can produce: • Abnormal ST segment elevation • Ischemic ST segment depression • Normal or nonnon-diagnostic ECG changes Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Myocardial Infarction— Infarction—ECG Findings z STST-Segment Elevation MI (STEMI) ¾ ¾ z HighHigh-Risk UA/nonUA/non-STST-Elevation MI (NSTEMI) ¾ ¾ z ST segment elevation >1 mm in 2 adjacent leads new LBBB ST segment depression >0.5 mm lasting 20 min. T-wave inversion with pain Normal or nondiagnostic ECG changes ¾ Inconclusive changes Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Myocardial Infarction ECG Imposters z z z z z z Left bundle branch block Some ventricular rhythms Left ventricular hypertrophy Pericarditis Ventricular aneurysm Early repolarization Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 132 Myocardial Infarction— Infarction—Management z z z z z z z Oxygen Aspirin Nitroglycerin Morphine 1212-lead ECG Fibrinolytic screening Transport to appropriate facility Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. ST Segment Elevation Likely with Acute Injury Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. STST-Elevation and Infarct Location Lead Location of Infarction Coronary Artery Involved II, III, aVF Inferior wall (most common) Right V1, V2 Septal wall Left V3, V4 Anterior wall (most lethal) Left I, aVL, V5, V6 Lateral wall Left V4R, V5R, V6R Right ventricle Right Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 133 Multilead Assessment of the Heart Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Left Ventricular Failure (LVF) and Pulmonary Edema z Left ventricle fails to function as an effective forward pump z Causes backback-pressure of blood into pulmonary circulation Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. LVF and Pulmonary Edema z Caused by heart disease, including: Ischemic Valvular ¾ Hypertensive heart disease ¾ ¾ z Untreated LVF leads to pulmonary edema Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 134 LVF— LVF—Signs and Symptoms z z z z z z z Respiratory distress Apprehension, agitation, confusion Cyanosis (if severe) Diaphoresis Adventitious lung sounds JVD Abnormal vital signs Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Pulmonary Edema— Edema—Management z z z z z z z z Oxygen, IV, monitor 1212-lead ECG Nitroglycerin (SBP >100) Furosemide Morphine CPAP Reversible causes Dobutamine or dopamine for shock Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Right Ventricular Failure (RVF) z Right ventricle fails as effective forward pump z BackBack-pressure of blood into systemic venous circulation Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 135 RVF z Causes Chronic hypertension (LVF precedes RVF) COPD ¾ Pulmonary embolism ¾ Valvular heart disease ¾ Right ventricular infarction ¾ ¾ z RVF usually results from LVF Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. RVF z Signs and symptoms Tachycardia Venous congestion • Engorged liver, spleen, or both • Venous distention • Peripheral edema ¾ Fluid accumulation in serous cavities ¾ ¾ z Management Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Cardiogenic Shock z Most extreme form of pump failure z Left ventricular function is so compromised heart cannot meet metabolic needs of body z Extensive myocardial infarction ¾ ¾ 40% of left ventricle Diffuse ischemia Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 136 Cardiac Tamponade z Impaired diastolic filling of heart z Increased fluid in pericardial space z Volume of pericardial fluid encroaches on capacity of atria and ventricles to fill adequately z Ventricular filling is mechanically limited, and stroke volume is decreased Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Cardiac Tamponade Acute onset z ¾ Trauma z Presentation ¾ ¾ Gradual onset z ¾ ¾ ¾ ¾ Neoplasm Infection Renal disease Hypothyroidism Management z ¾ ¾ ¾ ¾ ¾ ¾ ¾ ¾ Chest pain Tachycardia Ectopy JVD Decreased SBP Pulsus paradoxus Muffled heart sounds ECG changes Fluid Pericardiocentesis Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Thoracic and Abdominal Aortic Aneurysms z Aneurysm ¾ z Dilation of a vessel Causes ¾ ¾ ¾ ¾ Atherosclerotic disease (most common) Infectious disease (primarily syphilis) Traumatic injury Certain genetic disorders (e.g., Marfan's syndrome) Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 137 Aortic Aneurysms—Signs and Symptoms z Hypotension z Peritoneal irritation z Syncope z Urge to defecate z Abdominal or back pain z Pulsatile, tender mass z Distal pulses present or absent z GI bleeding ¾ z Tearing or ripping Low back or flank pain ¾ Radiates to thigh, groin, testicle Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Branches of Aorta Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Pathogenesis of Dissecting Aneurysms Medial and intimal degeneration in aortic wall Hemodynamic forces produce tear Dissecting hematoma propagated by pulse wave Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 138 Dissecting Aneurysms—Management z Gentle handling z Oxygen z Monitor z IV fluids ¾ Bolus if profound shock Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Acute Arterial Occlusion z Blockage of arterial flow caused by: Trauma Embolus ¾ Thrombosis ¾ ¾ z Severity of episode depends on: ¾ ¾ Site of occlusion Collateral circulation Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Acute Arterial Occlusion z Signs and symptoms ¾ Pain in extremity • May be severe and sudden in onset or absent because of paresthesia Pallor ¾ Cool skin distal to occlusion ¾ Change in sensory and motor function ¾ Diminished or absent pulse distal to injury ¾ Bruit over affected vessel ¾ Slow capillary filling ¾ Sometimes shock ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 139 Arterial Occlusion—Management z Extremity occlusion is painful and limb threatening if blood flow is not reestablished within 44-8 hrs z Immobilize limb and transport z Patients with mesenteric occlusion ¾ ¾ Manage for shock: • Oxygen • IV fluids Analgesics for pain control Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Common Sites of Embolic Arterial Occlusion Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Venous Thrombosis z Predisposing factors History of trauma Sepsis ¾ Stasis or inactivity ¾ Recent immobilization ¾ Pregnancy ¾ Birth control pills ¾ Malignancy ¾ Coagulopathies ¾ Smoking ¾ Varicose veins ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 140 Acute Deep Vein Thrombosis (DVT) z Occlusion of deep veins is serious, common problem z May involve any portion of deep venous system ¾ More common in lower extremities Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Acute DVT— DVT—Risk Factors z Lower extremity trauma z Previous thrombosis z Recent surgery z Oral contraceptives z Advanced age z Cancer z Recent MI z Obesity z Inactivity z CHF Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Acute DVT— DVT—Management z Risk of pulmonary embolus z Hospitalization z Bed rest z Anticoagulants Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 141 Common Sites of Atherosclerotic Occlusive Disease Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Hypertension z Resting BP: Consistently >140/90 mm Hg z Several categories of hypertension based on level of blood pressure, symptoms, and urgency of need for intervention Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Chronic Hypertension z Conditions associated with chronic, uncontrolled hypertension Cerebral hemorrhage and stroke Myocardial infarction ¾ Renal failure (secondary to vascular changes in the kidney) ¾ Thoracic and/or abdominal aortic aneurysm ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 142 Hypertensive Emergencies z Blood pressure increase leads to significant, irreversible endend-organ damage within hours if not treated z Organs most at risk are brain, heart, and kidneys Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Hypertensive Emergencies z Myocardial ischemia with hypertension z Aortic dissection with hypertension z Pulmonary edema with hypertension z Hypertensive intracranial hemorrhage z Toxemia z Hypertensive encephalopathy Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Hypertensive Emergencies— Signs and Symptoms z z z z z z Paroxysmal nocturnal dyspnea Shortness of breath Altered mental status Vertigo Headache Epistaxis z z z z z Tinnitus Changes in visual acuity Nausea and vomiting Seizures ECG changes Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 143 Hypertensive Encephalopathy z Severe hypertension produces hypertensive encephalopathy and cerebral hypoperfusion z Loss of integrity of bloodblood-brain barrier z Fluid exudation into brain tissue Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Hypertensive Encephalopathy z Progresses from: ¾ z Severe headache, nausea, vomiting, aphasia, hemiparesis, and transient blindness Later ¾ Seizures, stupor, coma, and death Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Hypertensive Emergencies z z z z z z Supportive care Oxygen IV ECG monitoring Rapid transport Drugs under medical supervision Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 144 Techniques for Managing Cardiac Emergencies z z z z z z Basic life support Mechanical CPR devices MonitorMonitor-defibrillators Implantable cardiovertercardioverter-defibrillators (ICDs) Transcutaneous cardiac pacing (TCP) Advanced cardiac life support (ACLS) system Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Basic Life Support z z z z z z z CPR within 4 min Compression/ventilation ratio 30:2 Compressions must be at least 100/min Depth of 11-1/2 to 2 inches Allow complete chest recoil Minimize interruptions of CPR Externally supports circulation and respiration Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mechanical CPR Devices z Designed to: ¾ ¾ ¾ ¾ Standardize CPR technique Eliminate rescuer fatigue Free rescuers to perform ACLS procedures Provide adequate compression during patient transport Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 145 Impedence Threshold Devices z z Attach to ET or mask During Pulseless Arrest: Increases blood flow to heart and brain Doubles systolic pressure Increases survival to hospital Increases defibrillation success AHA Class IIa in intubated patients ¾ ¾ ¾ ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Automated External Defibrillators z Analyze ECG signal ¾ z Including frequency, amplitude, and wave morphology Designed for use by individuals with minimal training Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Defibrillation z Delivery of electrical current through chest wall to terminate VF and pulseless VT Shock depolarizes a large mass of myocardial cells at once ¾ If 75% of cells are in resting state (depolarized) after shock is delivered, normal pacemaker may resume discharging ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 146 Defibrillation z Early defibrillation VF is most frequent initial rhythm in arrest Treatment for VF is electrical defibrillation ¾ Chance of successful defibrillation diminishes rapidly over time ¾ VF tends to convert to asystole within a few minutes ¾ If prehospital arrest is unwitnessed, 2 minutes of CPR may enhance ability to defibrillate ¾ ¾ Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Paddle Electrodes z Apex or sternum z Place so that the heart is in path of current and distance between electrodes and the heart is minimized Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Stored and Delivered Energy z Electrical energy measured in joules ¾ z Delivered energy about 80% of stored energy ¾ ¾ z Watt seconds Losses within defibrillator circuitry Resistance to current flow across chest wall 80% of stored energy approximates amount of joules delivered to patient Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 147 Monitor Defibrillator Pacer Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Defibrillator Safety z Clear all personnel from patient, bed, and defibrillator before shock delivery z Do not make contact with patient except through defibrillator paddle handles Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Defibrillator Safety z Do not use excessive gel or coupling material z Do not discharge paddles over a pacemaker or ICD generator or nitroglycerin paste z Remove nitroglycerin patches before defibrillation Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 148 Defibrillator Safety z Apply gel or paste before turning on defibrillator z Do not discharge defibrillator in open air to rid unwanted charge z Turn defibrillator off to dump charge z Do not discharge defibrillator with paddles placed together Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Defibrillator Safety z Do not touch metal electrodes or hold paddles to your body when defibrillator is on z Clean paddles after use z Routinely check defibrillator to make sure equipment is functioning properly ¾ Including batteries Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Defibrillator Use in Special Environments z Can defibrillate in wet conditions ¾ ¾ Keep chest dry between defibrillator electrode sites Keep operator's hands and paddle handles as dry as possible • In a rainstorm, finding shelter would be safest Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 149 Defibrillator Use in Special Environments Video Clip: Defibrillation Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Implantable CardioverterCardioverter-Defibrillator (ICD) z Implanted through median sternotomy incision ¾ z Other approaches also used ICD monitors patient's cardiac rhythm, rate, and QRS morphology Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. ICD Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 150 Synchronized Cardioversion z z Terminates dysrhythmias other than VF and pulseless VT Delivers shock about 10 msec after peak of QRS complex ¾ ¾ ¾ ¾ z Avoid relative refractory period May reduce energy needed to end dysrhythmia Decreases potential for development of secondary complicating dysrhythmias Procedure Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Synchronized Cardioversion Video Clip: Cardioversion Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Transcutaneous Cardiac Pacing (TCP) z External cardiac pacing z Treatment for bradycardia z Indications z Contraindications Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 151 TCP— TCP—Proper Electrode Placement Preferred anterior-posterior placement Alternate anterior-anterior placement Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. TCP— TCP—Proper Electrode Placement Video Clip: Transcutaneous Pacing Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Cardiac Arrest and Sudden Death z Resuscitation in prehospital setting best chance for survival z Rapid ACLS protocol initiated without delaying transport to hospital Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 152 Termination of Resuscitation z Inclusion criteria z Exclusion criteria z Procedure z Special considerations Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Conclusion About two thirds of cases of sudden death due to coronary disease take place outside the hospital. This usually occurs within 4 hours after onset of symptoms. It is possible that a large number of these deaths could be prevented by rapid entry into the EMS system, effective early CPR, and early defibrillation. Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Questions? Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. Mosby, Inc. items and derived items © 2007, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 153