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
Cardiovascular disease wikipedia , lookup
Electrocardiography wikipedia , lookup
Management of acute coronary syndrome wikipedia , lookup
Coronary artery disease wikipedia , lookup
Cardiac surgery wikipedia , lookup
Quantium Medical Cardiac Output wikipedia , lookup
Heart arrhythmia wikipedia , lookup
Dextro-Transposition of the great arteries wikipedia , lookup
Chapter 8 Cardiovascular Drugs Copyright © 2011 Delmar, Cengage Learning Basic Anatomy and Physiology • The functions of the cardiovascular system include delivery of oxygen, nutrients, and hormones to the various parts of the body • The cardiovascular system also transports waste products to the appropriate waste removal system Copyright © 2011 Delmar, Cengage Learning Basic Anatomy and Physiology Copyright © 2011 Delmar, Cengage Learning Basic Anatomy and Physiology • The electrical impulses of the heartbeat originate in the sinoatrial node (SA node) • Heart rate is controlled primarily by the autonomic nervous system: – Stimulation of the parasympathetic nervous system slows heart rate – Stimulation of the sympathetic nervous system increases heart rate Copyright © 2011 Delmar, Cengage Learning Basic Anatomy and Physiology • Heart rhythm – Contractions at regular intervals – Systole is contraction of heart chambers – Diastole is relaxation of heart chambers – Normal heart beat is called normal sinus rhythm Copyright © 2011 Delmar, Cengage Learning Basic Anatomy and Physiology • Workload of the heart is divided into preload and afterload – Preload: volume of blood entering the right side of the heart – Afterload: force needed to push blood out of the ventricles • If the heart is not working properly, it can compensate by a few mechanisms: – – – – Increase heart rate Increase stroke volume Increase efficiency Enlarge itself Copyright © 2011 Delmar, Cengage Learning Basic Anatomy and Physiology • There are 3 major types of blood vessels: arteries, veins, and capillaries – An artery is a blood vessel that carries blood away from the heart – Veins are low-pressure collecting system that returns blood to the heart – Capillaries are single-cell-thick vessels that connect the arterial and venous systems Copyright © 2011 Delmar, Cengage Learning Basic Anatomy and Physiology • Blood pressure – Flows from areas of higher pressure to areas of lower pressure – Determined by heart rate, stroke volume, peripheral resistance Copyright © 2011 Delmar, Cengage Learning Basic Anatomy and Physiology • Blood supplies body tissues with oxygen, nutrients, and various chemicals • Blood transports waste products to various organs for removal from the body • Blood cells also play an important role in the immune and endocrine systems Copyright © 2011 Delmar, Cengage Learning Cardiovascular Conditions • Congestive heart failure is a syndrome that can occur with any disorder that damages or overworks the heart muscle – Conditions that lead to congestive heard failure include: • Cardiomyopathy (caused by infections, genetic disorders, or degeneration) • Hypertension • Valvular disease Copyright © 2011 Delmar, Cengage Learning Cardiovascular Conditions • Cardiac arrhythmias is a disruption in the cardiac rate or rhythm – Arrhythmias interfere with the work of the heart and can disrupt cardiac output – Can be caused by changes in the rate, stimulation from an ectopic focus, or by alterations in conduction of the muscle – These changes can be caused by electrolyte disturbances, decrease in oxygen delivered to the cells, structural damage, accumulation of waste products, and acidosis Copyright © 2011 Delmar, Cengage Learning Cardiovascular Disease • Alterations in blood pressure may result in hypertension (increased blood pressure) or hypotension (decreased blood pressure) – Hypertension results in prolonged force put on the vessels of the vascular system • Leads to left ventricle thickening – Hypotension results in the tissues of the body not receiving sufficient amount of oxygenated blood • Allows wasted products to accumulate and cells to die from lack of oxygen Copyright © 2011 Delmar, Cengage Learning Cardiovascular Drugs • Types of cardiovascular drugs – Positive inotropic drugs: increase the force of myocardial contraction – Negative inotropic drugs: decrease the force of myocardial contraction – Positive chronotropic drugs: increase heart rate by altering the rate of impulse formation at the SA node – Negative chronotropic drugs: decrease heart rate by altering the rate of impulse formation at the SA node – Positive dromotropic drugs: increase the conduction of electrical impulses – Negative dromotropic drugs: decrease the conduction of electrical impulses Copyright © 2011 Delmar, Cengage Learning Increasing Force • Positive inotropes – Cardiac glycosides: • Increase the strength of cardiac contractions, decrease heart rate, have an antiarrhythmic effect, and decrease signs of dyspnea • Side effects include anorexia, vomiting, diarrhea, and cardiac arrhythmias • Examples include digoxin and digitoxin – Catecholamines: • Increase the force and rate of myocardial contraction, constrict peripheral blood vessels, and increase blood glucose levels • Examples include epinephrine, dopamine, dobutamine, and isoproterenol Copyright © 2011 Delmar, Cengage Learning Increasing Force • Positive inotropes – Benzimidazole-pyridazinones: • Increase the force of contraction • Cause widening of the blood vessels • Side effects include anorexia, lethargy, diarrhea, and dyspnea Copyright © 2011 Delmar, Cengage Learning Fixing the Rhythm • Antiarrhythmic drugs – Used to correct variation in the normal beating of the heart (which can lead to reduced cardiac output) – Types of antiarrhythmic drugs include local anesthetics, membrane stabilizers, beta-adrenergic blockers, action potential prolongation drugs, and calcium-channel blockers – For examples of antiarrhythmic drugs refer to Table 8-3 in your textbook Copyright © 2011 Delmar, Cengage Learning Correcting Constriction • Vasodilators – Drugs used to dilate arteries and/or veins, which alleviates vessel constriction and improves cardiac output – Examples include angiotensin-converting enzyme inhibitors, arteriole dilators, venodilators, and combined vasodilators Copyright © 2011 Delmar, Cengage Learning Correcting Constriction • Calcium channel blockers are used to treat CHF and hypertension • Calcium channel blockers inhibit the movement of calcium through the the myocardial cell membranes and vascular smooth muscle – Decreases the force of cardiac contractions – Side effects include hypotension and anorexia Copyright © 2011 Delmar, Cengage Learning Losing Fluid • Diuretics – Drugs that increase the volume of urine excreted by the kidneys and thus promote the release of water from the tissues (lowers the fluid volume in tissue) – Used in the treatment of hypertension – Categories of diuretics include thiazides, loop diuretics, potassium-sparing diuretics, osmotics, and carbonic anhydrase inhibitors – For examples refer to Table 8-4 in your textbook Copyright © 2011 Delmar, Cengage Learning Clot Stopping • Anticoagulants – Inhibit clot formation by inactivating one or more clotting factors – Used to inhibit clotting in catheters, to prevent blood samples from clotting, to preserve blood transfusions, and to treat emboli – Examples include heparin, EDTA, coumarin derivatives, aspirin, and blood transfusion anticoagulants Copyright © 2011 Delmar, Cengage Learning Clot Stopping • Clopidogrel bisulfate is an oral platelet aggregation inhibitor – May prevent thrombi in cats – Improves circulation in cats following an embolic event – Side effects are gastrointestinal in nature and include vomiting and anorexia Copyright © 2011 Delmar, Cengage Learning Bleeding Control • Hemostatic drugs – Help promote the clotting of blood – May be parenteral or topical – Parenteral • Vitamin K1 • Protamine sulfate – Topical • Silver nitrate, hemostat powder, gelfoam gelatin sponges, thrombogen topical thrombin solution Copyright © 2011 Delmar, Cengage Learning Blood Enhancing Drugs • Affect RBCs • Affect the production or quality of RBCs • Examples: – Iron – Erythropoietin Copyright © 2011 Delmar, Cengage Learning Blood Enhancing • Erythropoietin is a protein made by the kidneys that stimulates the differentiation of bone marrow stem cells to form red blood cells – Used to treat anemia in animals with chronic renal failure – Allergic reactions are sometimes seen with erythropoietin products – Erythropoietin products must be refrigerated Copyright © 2011 Delmar, Cengage Learning Blood Enhancing • Cyanocobalamine is B12 and is used to treat B12 deficiencies – Oral forms are not appropriate for small animals • Folic acid is a B vitamin needed for normal erythropoiesis – May be seen in dogs, cats, and horses due to small intestinal disease – Very few side effects Copyright © 2011 Delmar, Cengage Learning