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Antiarrhythmic Agents: Cardiac Stimulants and Depressants

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Presentation on theme: "Antiarrhythmic Agents: Cardiac Stimulants and Depressants"— Presentation transcript:

1 Antiarrhythmic Agents: Cardiac Stimulants and Depressants
Chapter 16 Antiarrhythmic Agents: Cardiac Stimulants and Depressants

2 The Heart Four-chambered 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 Generates and conducts electrical impulses Heart rate is controlled by the autonomic nervous system

3 The Heart Main pacemakers of heart:
Sinoatrial node: bpm; primary pacemaker Atrioventricular node: Connects atria and ventricles; bpm Bundle of His and Purkinje fibers: carry electrical impulses from AV node to complete ventricle rate pacing; bpm

4 Cardiac medications Increase /decrease the force of the myocardial contraction Increase / decrease the heart rate Increase / decrease the conduction of electrical impulses through the myocardium

5 Congestive Heart Failure (CHF)
Cardiac glycosides -Digoxin -Treat arrhythmias

6 Cardiac Glycosides Derived from natural sources; treatment for heart failure: cardiac distention-inability to pump the full blood volume cardiac hypertrophy-prolonged stretching sodium and water retention-decreased renal blood flow Results in weight gain, edema, shortness of breath, and pulmonary congestion

7 Digoxin Decreases electrical conduction Negative Dromatotropic Effect
Increases time spent in diastole Increases the force of the myocardial contraction Positive inotropic action End result: slows and strengthens contractions

8 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

9 Digoxin Low therapeutic index
Toxicity can be life-threatening; occurs in 10-20% of patients Many drug-drug, drug herbal interactions Routine monitoring of serum potassium and digoxin levels

10 Digoxin: Adverse Effects
Gastrointestinal effects Nausea and vomiting Anorexia Diarrhea Cardiac effects Cardiac arrhythmias Neurological effects

11 Cardiac Glycoside Toxicity
Predispose to cardiac glycoside toxicity Hypokalemia Renal impairment Rapid IV administration

12 Cardiac Glycoside Toxicity
Treatment Stop the drug Physical assessment Check potassium level Administer if needed Monitor heart rate Administer antiarrhythmics

13 Nursing Considerations
Apical pulse for 1 minute. Hold if HR < 60 bpm Report changes in heart rhythm Assess for symptoms of toxicity Monitor digoxin blood levels Monitor for drug-drug and drug-herbal interactions Educate : signs of toxicity and how to monitor pulse rate .

14 Antiarrhythmic and Antidysrhythmic Drugs
Grouped together according to their similar actions Work three ways: Decrease automaticity of cardiac tissues in the ectopic sites Alter rate of conduction Alter refractory period of cardiac muscle between consecutive contractions

15 Antiarrythmic Agents Dependent on: type of dysrhythmia
presence of other conditions safety of the drug onset and/or duration of drug action Administered IV until patient stabilized, then oral agents given Arranged into classes

16 Antidysrhythmic Medications
Class 1 (1A, 1B, 1C): decrease the influx of sodium ions, stabilizing membranes Class 2: decrease contractility, B/P, AV node conduction Class 3: Prolong action potential, refractory period Class 4: Decrease myocardial contractility, 02 demand

17 Antidysrhythmics Quinidine gluconate – Class 1 Lidocaine – Class 1B
Dilantin – Class 1B Propranolol – Class 2 Verapamil HCL – Class 4 Digoxin – Class 4

18 Adverse Effects GI upset Cardiovascular disorders Hypersensitivity
Hypotension Bradycardia Lightheadedness

19 Nursing Considerations
Take patients apical pulse for one minute Record rate and rhythm of the heartbeat Assess allergies Monitor blood pressure Patient should be supine when administering IV agents .

20 Beta-adrenergic Blocking Agents
Block the hormone epinephrine Inhibit beta and beta2 sympathetic receptors Reduce heart rate Reduces contractility Slow electrical conduction Decrease the blood pressure

21 Beta-Adrenergic Blocking Agents
Adverse effects Cause bronchoconstriction Can cause heart failure Examples: propranolol (Inderal), esmolol, bretylium tosylate (Bretylol)

22 Calcium Channel Antagonists
Reduce the influx of calcium into the cell: Prevention of reversal of spasms of the coronary blood vessels Coronary artery dilation Reduction of myocardial oxygen consumption Example: Verapamil .

23 Adverse Effects Vasodilation may cause: Hypotension Edema Dizziness
Headache Slower myocardial conduction may cause: Bradycardia Heart failure Other effects: Constipation, diarrhea, nausea, fatigue

24 Patient Education Ensure understanding of drug regime
Review signs to report to their health care provider Instruct patient how to take their pulse Remind them of the importance for proper follow-up Encourage questions

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