© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

• 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
© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

• 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
© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

• 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
© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

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
© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

Cardiovascular Drugs
• 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
© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

Cardiovascular Drugs
• 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, betaadrenergic blockers, action potential prolongation drugs, and calcium-channel blockers
– Examples of antiarrhythmic drugs are listed in
Table 8-3
© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

Cardiovascular Drugs
– Drugs used to dilate arteries and/or veins, which alleviates vessel constriction and improves cardiac output
– Examples include angiotensinconverting enzyme inhibitors, arteriole dilators, venodilators, and combined vasodilators
© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

Cardiovascular Drugs
• 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
– Examples are listed in Table 8-4
© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

Cardiovascular Drugs
– 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
© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

Cardiovascular Drugs
– Help promote the clotting of blood
– May be parenteral or topical
– Parenteral
• Vitamin K
1
• Protamine sulfate
– Topical
• Silver nitrate, hemostat powder, gelfoam gelatin sponges, thrombogen topical thrombin solution
© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

Cardiovascular Drugs
– Affect RBCs
– Affect the production or quality of RBCs
– Examples:
• Iron
• Erythropoietin
© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.