Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 4 Atrial Mechanisms
Document related concepts
Transcript
Chapter 4 Atrial Rhythms 1 Objectives Explain the concepts of altered automaticity, triggered activity, and reentry. Explain the terms bigeminy, trigeminy, quadrigeminy, and run when used to describe premature complexes. Describe the ECG characteristics, possible causes, signs and symptoms, and initial emergency care for premature atrial complexes (PACs). Explain the difference between a compensatory and noncompensatory pause. Explain the terms wandering atrial pacemaker and multifocal atrial tachycardia. Describe the ECG characteristics, possible causes, signs and symptoms, and initial emergency care for wandering atrial pacemaker (multiformed atrial rhythm). Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 2 Objectives Describe the ECG characteristics, possible causes, signs and symptoms, and initial emergency care for multifocal atrial tachycardia (MAT). Describe the ECG characteristics, possible causes, signs and symptoms, and initial emergency care for atrial tachycardia (AT). Discuss preexcitation syndrome and name its three major forms. Explain the terms paroxysmal atrial tachycardia (PAT) and paroxysmal supraventricular tachycardia (PSVT). List four examples of vagal maneuvers. Discuss the indications and procedure for synchronized cardioversion. Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 3 Objectives Describe the ECG characteristics, possible causes, signs and symptoms, and initial emergency care for atrioventricular nodal reentrant tachycardia (AVNRT). Describe the ECG characteristics, possible causes, signs and symptoms, and initial emergency care for atrioventricular reentrant tachycardia (AVRT). Describe the ECG characteristics, possible causes, signs and symptoms, and initial emergency care for atrial flutter. Describe the ECG characteristics, possible causes, signs and symptoms, and initial emergency care for atrial fibrillation (AFib). Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 4 Introduction Atria Thin-walled, lowpressure chambers Receive blood from systemic circulation and lungs “Atrial kick” Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 5 Atrial Dysrhythmias: Mechanisms Atrial dysrhythmias reflect abnormal electrical impulse formation and conduction in the atria. Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 6 Atrial Dysrhythmias: Mechanisms Atrial dysrhythmias may occur because of: Altered automaticity Triggered activity Reentry Altered automaticity and triggered activity are disorders in impulse formation Reentry is a disorder in impulse conduction Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 7 Altered Automaticity Can occur in: Normal pacemaker cells Myocardial working cells that do not normally function as pacemaker sites These cells depolarize and initiate impulses before a normal impulse Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 8 Triggered Activity Results from abnormal electrical impulses that sometimes occur during repolarization (afterdepolarizations), when cells are normally quiet Requires a stimulus to initiate depolarization Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 9 Reentry (Reactivation) A condition in which an impulse returns to stimulate tissue that was previously depolarized Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 10 Reentry (Reactivation) Reentry requires: A potential conduction circuit or circular conduction pathway A block within part of the circuit Delayed conduction with the remainder of the circuit Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 11 Reentry (Reactivation) Reentry results in a single premature beat or repetitive electrical impulses resulting in short periods of rapid rhythms Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 12 Atrial Dysrhythmias Most atrial dysrhythmias are not lifethreatening Some are associated with extremely fast ventricular rates An excessively rapid heart rate may compromise cardiac output Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 13 Premature Complexes Premature beats may be produced by: Atria AV junction Ventricles Premature beats appear early, that is, they occur before the next expected beat Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 14 Premature Complexes Premature beats are identified by their site of origin Premature atrial complexes (PACs) Premature junctional complexes (PJCs) Premature ventricular complexes (PVCs) Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 15 Premature Complexes — Patterns Pairs (coupled) “Runs” or “bursts” Every other beat is a premature beat Trigeminy Three or more premature beats in a row Bigeminy Two premature beats in a row Every third beat is a premature beat Quadrigeminy Every fourth beat is a premature beat Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 16 Premature Atrial Complexes Occur when an irritable site within the atria discharges before the next SA node impulse is due to discharge The P wave of a PAC may be: Biphasic (partly positive, partly negative) Flattened Notched Pointed Lost in the preceding T wave Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 17 PACs— How Do I Recognize Them? Rate Usually within normal range, but depends on underlying rhythm Rhythm Regular with premature beats Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 18 PACs— How Do I Recognize Them? S = SA node; P waves = atrial beat Premature (occurring earlier than the next expected sinus P wave), positive (upright) in lead II, one before each QRS complex, often differ in shape from sinus P waves–may be flattened, notched, pointed, biphasic, or lost in the preceding T wave Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 19 PACs— How Do I Recognize Them? PR interval May be normal or prolonged depending on the prematurity of the beat QRS duration Usually 0.10 sec or less but may be wide (aberrant) or absent, depending on the prematurity of the beat; the QRS of the PAC is similar in shape to those of the underlying rhythm unless the PAC is abnormally conducted Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 20 PACs— How Do I Recognize Them? Sinus tachycardia at 111 bpm with three PACs Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 21 PACs— How Do I Recognize Them? Rate Usually within normal range, but depends on underlying rhythm Rhythm P waves Regular with premature beats Premature (occurring earlier than the next expected sinus P wave), positive (upright) in lead II, one before each QRS complex, often differ in shape from sinus P waves–may be flattened, notched, pointed, biphasic, or lost in the preceding T wave PR interval QRS duration May be normal or prolonged depending on the prematurity of the beat Usually 0.10 sec or less but may be wide (aberrant) or absent, depending on the prematurity of the beat; the QRS of the PAC is similar in shape to those of the underlying rhythm unless the PAC is abnormally conducted Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 22 Compensatory/Noncompensatory Pause A “noncompensatory” (incomplete) pause often follows a PAC Represents the delay during which the SA node resets its rhythm for the next beat Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 23 Compensatory/Noncompensatory Pause To determine whether a pause following a premature complex is compensatory or noncompensatory: Measure the distance between three normal beats Compare that distance between three beats, one of which includes the premature complex Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 24 Compensatory/Noncompensatory Pause The pause is termed “noncompensatory” (incomplete) if the normal beat following the premature complex occurs before it was expected When the distance is NOT the same The pause is “compensatory” (complete) if the normal beat following the premature complex occurs when expected When the distance is the same Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 25 Aberrantly Conducted PACs PACs associated with a wide QRS complex are called “aberrantly conducted” PACs Indicates conduction through ventricles is abnormal Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 26 Nonconducted PACs A PAC may occur very prematurely and close to the T wave of the preceding beat Only a P wave may be seen with no QRS after it (appearing as a pause) This is a “nonconducted” or “blocked” PAC P wave occurred too early to be conducted Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 27 PACs— What Causes Them? Emotional stress Congestive heart failure Acute coronary syndromes Mental and physical fatigue Atrial enlargement Digitalis toxicity Valvular heart disease Electrolyte imbalance Hyperthyroidism Stimulants: caffeine, tobacco, cocaine Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 28 PACs— What Do I Do About Them? Occasional PACs usually do not require treatment Frequent PACs may initiate episodes of atrial fibrillation, atrial flutter, or PSVT Frequent PACs are treated by correcting the underlying cause: Stress reduction Reduced consumption of caffeine-containing beverages Treatment of congestive heart failure Correction of electrolyte imbalance Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 29 Wandering Atrial Pacemaker Multiformed atrial rhythm Updated term for the rhythm formerly known as wandering atrial pacemaker Size, shape, and direction of P waves vary Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 30 Wandering Atrial Pacemaker— How Do I Recognize It? Rate Usually 60–100 bpm, but may be slow. If the rate is more than 100 bpm, the rhythm is termed multifocal (or chaotic) atrial tachycardia Rhythm May be irregular as pacemaker site shifts from SA node to ectopic atrial locations and AV junction Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 31 Wandering Atrial Pacemaker— How Do I Recognize It? P Waves Size, shape, and direction may change from beat to beat PR Interval Variable QRS Usually 0.10 sec or less unless an intraventricular conduction delay exists Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 32 Wandering Atrial Pacemaker— How Do I Recognize It? Rate Usually 60–100 bpm, but may be slow. If the rate is greater than 100 bpm, the rhythm is termed multifocal (or chaotic) atrial tachycardia. Rhythm May be irregular as the pacemaker site shifts from the SA node to ectopic atrial locations and the AV junction P Waves Size, shape, and direction may change from beat to beat. At least three different P wave configurations (seen in the same lead) are required for a diagnosis of wandering atrial pacemaker or multifocal atrial tachycardia. PR Interval Variable QRS Usually 0.10 sec or less unless an intraventricular conduction delay exists Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 33 Wandering Atrial Pacemaker— What Causes It? May be observed in normal, healthy hearts (particularly in athletes) and during sleep May also occur with some types of organic heart disease and with digitalis toxicity Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 34 Wandering Atrial Pacemaker— What Do I Do About It? Usually produces no signs and symptoms unless associated with a slow rate If the rhythm occurs because of digitalis toxicity, the drug should be withheld Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 35 Multifocal Atrial Tachycardia— How Do I Recognize It? When wandering atrial pacemaker is associated with a ventricular rate greater than 100 bpm, the rhythm is called “multifocal atrial tachycardia” (MAT) or chaotic atrial tachycardia Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 36 Multifocal Atrial Tachycardia— What Causes It? Most often seen in: Severe COPD Hypoxia Acute coronary syndromes Digoxin toxicity Rheumatic heart disease Theophylline toxicity Electrolyte imbalances • Hypokalemia • Hypomagnesemia Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 37 Multifocal Atrial Tachycardia— What Do I Do About It? Treatment is directed at the underlying cause If patient is symptomatic but you are uncertain rhythm is MAT: Vagal maneuvers, adenosine If you know the rhythm is MAT and the patient is symptomatic, consult cardiologist Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 38 Vagal Maneuvers Coughing Squatting Breath-holding Carotid sinus massage Application of a cold stimulus to the face Valsalva’s maneuver Gagging Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 39 Carotid Sinus Massage Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 40 Carotid Sinus Massage Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 41 Carotid Sinus Massage Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 42 Adenosine Can interrupt reentry pathways that involve the AV node Rapid onset of action Short half-life Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 43 Supraventricular Arrhythmias Begin above the bifurcation of the bundle of His Includes rhythms that begin in the: SA node Atrial tissue AV junction Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 44 Types of Supraventricular Tachycardias Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 45 Atrial Tachycardia Atrial tachycardia is a series of rapid beats from an atrial ectopic focus This rapid atrial rate overrides the SA node and becomes the pacemaker Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 46 Atrial Tachycardia Atrial tachycardia 3 or more PACs in a row at a rate of more than 100 bpm Paroxysmal atrial tachycardia (PAT) Atrial tachycardia that starts or ends suddenly Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 47 Atrial Tachycardia Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 48 Atrial Tachycardia— How Do I Recognize It? Atrial tachycardia is shown that ends spontaneously with the abrupt resumption of sinus rhythm. The P waves of the tachycardia (rate: about 150 bpm) are superimposed on the preceding T waves. Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 49 Atrial Tachycardia— How Do I Recognize It? Rate 100–250 bpm Rhythm Regular P Waves One P wave precedes each QRS complex in lead II; P waves differ in shape from sinus P waves; an isoelectric baseline is usually present between P waves; if the atrial rhythm originates in the low portion of the atrium, P waves will be negative in lead II. With rapid rates, it is difficult to distinguish P waves from T waves PR Interval May be shorter or longer than normal QRS 0.10 sec or less unless an intraventricular conduction delay exists Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 50 Atrial Tachycardia Paroxysmal atrial tachycardia with block Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 51 Atrial Tachycardia— What Causes It? Stimulant use Caffeine, albuterol, theophylline, cocaine Infection Electrolyte imbalance Acute illness with excessive catecholamine release Myocardial infarction Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 52 Atrial Tachycardia— What Do I Do About It? Possible signs and symptoms: Asymptomatic Palpitations Fluttering sensation in the chest Chest pressure Dyspnea Fatigue Dizziness or lightheadedness Syncope or near-syncope Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 53 Atrial Tachycardia— What Do I Do About It? If symptomatic due to rapid rate: Vagal maneuvers Adenosine drug of choice Calcium channel blockers Beta-blockers Amiodarone Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 54 Amiodarone Coronary and peripheral vasodilator Suppresses SA node function Prolongs PR, QRS, and QT intervals Slows conduction at the AV junction Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 55 Amiodarone Hypotension and bradycardia most common adverse effects Slow infusion rate or discontinue if seen Additive effect with other medications that prolong the QT interval Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 56 Synchronized Cardioversion Delivery of an electrical shock to the heart timed to occur during QRS Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 57 Cardioversion—Indications Tachycardias (except sinus tachycardia) with a ventricular rate greater than 150 bpm that have a clearly identifiable QRS complex (such as some narrow QRS tachycardias and ventricular tachycardia) Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 58 Cardioversion—Procedure Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 59 Cardioversion—Procedure Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 60 Cardioversion—Procedure Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 61 Cardioversion—Procedure Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 62 Cardioversion—Procedure Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 63 Cardioversion—Procedure Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 64 AV Nodal Reentrant Tachycardia (AVNRT) Most common type of SVT Caused by reentry in the area of the AV node Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 65 AVNRT— How Do I Recognize It? AVNRT is usually precipitated by a PAC Electrical circuit allows impulse to spin around in a circle Results in a very rapid and regular rhythm • Rate: 150–250 bpm Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 66 AVNRT— How Do I Recognize It? Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 67 AVNRT— How Do I Recognize It? Rate 150–250 bpm (usually 180 to 200 bpm in adults) Rhythm Regular P Waves Usually not identifiable; P wave usually hidden in T wave of preceding beat PR Interval Not measurable QRS 0.10 sec or less unless an intraventricular conduction delay exists Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 68 Paroxysmal Supraventricular Tachycardia (PSVT) Regular, narrow-QRS tachycardia that starts or ends suddenly P waves usually hidden in T waves of preceding beats Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 69 AVNRT— What Causes It? Common in individuals with no structural heart disease Triggers: Hypoxia Stress Anxiety Caffeine Smoking Sleep deprivation Many medications Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 70 AVNRT— What Causes It? AVNRT also occurs in individuals with: COPD Coronary artery disease Valvular heart disease Congestive heart failure Digitalis toxicity Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 71 AVNRT— What Do I Do About It? Possible signs and symptoms: Palpitations (common) Lightheadedness Neck vein pulsations Syncope or nearsyncope Dyspnea Weakness Nervousness, anxiety Chest pain or pressure Signs of shock Congestive heart failure Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 72 AVNRT— What Do I Do About It? Stable patient Oxygen, IV access, cardiac monitor Vagal maneuvers Adenosine Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 73 AVNRT— What Do I Do About It? If the patient is unstable: Oxygen, IV access, cardiac monitor Consider medication administration Consider sedation • If the patient is awake and time permits Synchronized cardioversion Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 74 AV Reentrant Tachycardia (AVRT) Atrioventricular reentry tachycardia (AVRT) involves a pathway of impulse conduction outside the AV node and bundle of His Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 75 AV Reentrant Tachycardia (AVRT) Preexcitation Impulse begins above the ventricles but travels via a pathway other than AV node and bundle of His Supraventricular impulse excites the ventricles earlier than normal Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 76 AV Reentrant Tachycardia (AVRT) Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 77 WPW— How Do I Recognize It? Short PR interval Delta wave QRS widening Secondary ST segment and T wave changes Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 78 WPW— How Do I Recognize It? Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 79 WPW— How Do I Recognize It? Rate Usually 60–100 bpm, if the underlying rhythm is sinus in origin Rhythm Regular, unless associated with atrial fibrillation P Waves Normal and positive in lead II unless WPW is associated with atrial fibrillation PR Interval If P waves are observed, less than 0.12 sec QRS Usually greater than 0.12 second; slurred upstroke of the QRS complex (delta wave) may be seen in one or more leads Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 80 AVRT Three main types of tachydysrhythmias that occur in WPW: AVRT (most common) Atrial fibrillation Atrial flutter Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 81 WPW— What Causes It? Common cause of tachydysrhythmias in infants and children Accessory pathway in WPW is likely to be congenital in origin Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 82 AVRT— What Do I Do About It? Common signs and symptoms associated with AVRT: Palpitations Lightheadedness Shortness of breath Anxiety Weakness Dizziness Chest discomfort Signs of shock Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 83 AVRT— What Do I Do About It? Consultation with a cardiologist is recommended Stable but symptomatic patient Oxygen, IV access, and IV medications such as amiodarone Unstable patient Synchronized cardioversion Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 84 Atrial Flutter Ectopic atrial rhythm in which an irritable site fires regularly at an extremely rapid rate Type I atrial flutter Type II atrial flutter Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 85 Atrial Flutter— How Do I Recognize It? Atrial flutter with 2:1 conduction Atrial flutter with 4:1 conduction Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 86 Atrial Flutter— How Do I Recognize It? Rate Atrial rate 250–450 bpm, typically 300 bpm; ventricular rate variable — determined by AV blockade; ventricular rate will usually not exceed 180 bpm due to intrinsic conduction rate of AV junction Rhythm Atrial regular, ventricular regular or irregular depending on AV conduction/blockade P Waves No identifiable P waves; saw-toothed “flutter” waves are present PR Interval Not measurable QRS 0.10 sec or less but may be widened if flutter waves are buried in the QRS complex or an intraventricular conduction delay exists Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 87 Atrial Flutter— What Causes It? Atrial flutter is usually a paroxysmal rhythm precipitated by a PAC May last for seconds to hours and occasionally lasts 24 hours or more Chronic atrial flutter is unusual Rhythm usually converts to sinus rhythm or atrial fibrillation, on its own or with treatment Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 88 Conditions Associated with Atrial Flutter Hypoxia Pulmonary embolism Chronic lung disease Mitral or tricuspid valve stenosis or regurgitation Pneumonia Complication of myocardial infarction Ischemic heart disease Cardiomyopathy Hyperthyroidism Digitalis or quinidine toxicity Cardiac surgery Pericarditis/myoca rditis Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 89 Atrial Flutter— What Do I Do About It? Cardiologist consult recommended If rapid ventricular rate, control ventricular response If rapid ventricular rate and serious signs and symptoms, synchronized cardioversion Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 90 Atrial Fibrillation (AFib) Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 91 Atrial Fibrillation— How Do I Recognize It? Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 92 Atrial Fibrillation— How Do I Recognize It? AFib can occur with complete AV block Ventricular rhythm will be slow and regular Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 93 Atrial Fibrillation— How Do I Recognize It? Rate Atrial rate usually 400–600 bpm; ventricular rate variable Rhythm Ventricular rhythm usually irregularly irregular P Waves No identifiable P waves, fibrillatory waves present; erratic, wavy baseline PR Interval Not measurable QRS 0.10 sec or less but may be widened if an intraventricular conduction delay exists Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 94 Atrial Fibrillation— What Causes It? Can occur in patients with or without detectable heart disease or related symptoms Increased stroke risk Atria do not contract effectively Blood pools within the atria, forming clots Clot dislodges and moves to artery in the brain Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 95 Conditions Associated with Atrial Fibrillation Idiopathic (no clear cause) Hypertension Ischemic heart disease Advanced age Rheumatic heart disease Cardiomyopathy Congestive heart failure Congenital heart disease Sick sinus syndrome WPW syndrome Pericarditis Pulmonary embolism Chronic lung disease After surgery Diabetes Stress Sympathomimetics Excessive caffeine Hypoxia Hypokalemia Hypoglycemia Systemic infection Hyperthyroidism Electrocution Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 96 Atrial Fibrillation— What Do I Do About It? Cardiologist consult recommended If rapid ventricular rate, control ventricular response If rapid ventricular rate and serious signs and symptoms, synchronized cardioversion Anticoagulation recommended if AFib has been present for 48 hours or longer Mosby items and derived items © 2011, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 97 Questions? 98
