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Chapter 17

Chapter 17. Cardiac Stimulants and Depressants. 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

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Chapter 17

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  1. Chapter 17 Cardiac Stimulants and Depressants

  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 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

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

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

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

  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 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

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

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

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

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

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

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

  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 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

  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 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

  15. Beta-adrenergic Blocking Agents • Inhibit beta1 and beta2 sympathetic receptors • Reduce heart rate • Reduce contractility • Decrease supraventricular and ventricular rhythms • Decrease blood pressure Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

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

  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 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

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

  19. Adrenergic or SympathomimeticDrugs • 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 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

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