1. Chapter 17 Cardiac Stimulants and Depressants

2. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 2 The Heart The heart is a four-chamber organ located in the upper left thoracic cavity. Purpose  Pumps the blood around the body so that oxygen and nutrients can be distributed to all areas of the body  Maintains the blood pressure at an acceptable level

3. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 3 Antiarrhythmics and Antianginals Cardiac illnesses  Cardiac stimulants  Cardiac depressants

4. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 4 Treatment of Heart Failure Cardiac glycosides  Digoxin  Treat arrhythmias

5. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 5 Digoxin Decreases electrical conduction Prolongs refractory period Increases the force of the myocardial contraction  Positive inotropic action

6. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 6 Digoxin: Dose Considerations Duration of action Method of administration Other  Physical size of the client  Other medications  Renal or hepatic function  Advanced age  Presence of other illnesses

7. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 7 Antiarrhythmics and Antianginals Require a digitalizing dose  To bring serum levels to a therapeutic level  All glycosides have a low therapeutic level

8. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 8 Gastrointestinal effects  Nausea and vomiting  Anorexia  Diarrhea Cardiac effects  Cardiac arrhythmias (continues) Antiarrhythmics and Antianginals: Side Effects

9. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 9 Antiarrhythmics and Antianginals: Side Effects Neurological effects  Restlessness  Irritability  Drowsiness  Vision changes  Headache (continued)

10. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 10 Cardiac Glycoside Toxicity Predispose to cardiac glycoside toxicity  Hypokalemia  Renal impairment  Rapid IV administration (continues)

11. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 11 Cardiac Glycoside Toxicity Treatment  Stop the drug  Physical assessment  Check potassium level  Administer if needed  Monitor heart rate  Administer antiarrhythmics (continued)

12. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 12 Antiarrhythmic and Antidysrhythmic Drugs Grouped together according to their similar actions

13. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 13 Antiarrhythmics and Antianginals: Drug Action Work three ways:  Decrease the automaticity of cardiac tissues in the ectopic sites  Alter the rate of conduction of electrical impulses through the heart.  Alter the refractory period of cardiac muscle between consecutive contractions

14. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 14 Antidysrhythmic Agents Group 1, 1A, 1B, 1C: decrease the influx of sodium ions, stabilizing membranes Group 2: depress phase 4 in depolarization Group 3: prolong repolarization in phase 3 Group 4: depress phase 4 depolarization and prolong repolarization of phases 1 and 2

15. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 15 Beta-adrenergic Blocking Agents Inhibit beta 1 and beta 2 sympathetic receptors Reduce heart rate Reduce contractility Decrease supraventricular and ventricular rhythms Decrease blood pressure

16. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 16 Antidysrhythmic Agents Adverse effects  Cause bronchoconstriction  Cause heart failure Examples: propanolol (Inderal), esmolol, bretylium tosylate (Bretylol)

17. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 17 Calcium Channel Antagonists Reduce the influx of calcium into the cell:  Prevention or reversal of spasms of the coronary blood vessels  Coronary artery dilation  Reduction of myocardial oxygen consumption Example: verapamil

18. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 18 Adenosine Slow conduction through the AV node Cardioverts paroxysmal supraventricular tachycardia (PSVT) Side effects  Facial flushing  Shortness of breath  Headache  Nausea and vomiting

19. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 17 - 19 Adrenergic or Sympathomimetic Drugs Affect alpha- or beta-adrenergic receptors Treat shock  Mimic epinephrine and/or norepinephrine  Cause increase in heart rate  Cause vasoconstriction  Reverse hypotension from shock  Cardiac or trauma