Medication Summary
Ebstein anomaly requires drug treatment for cardiovascular consequences resulting from tricuspid atrialization of the right ventricle, valvular regurgitation, and septal defects. Patients may require antibiotic prophylaxis for bacterial endocarditis. Treatment of SVT is typically by radiofrequency ablation rather than drug therapy. CHF is treated with ACE inhibitors, diuretics, and digoxin.
Diuretics
Class Summary
These agents promote excretion of water and electrolytes by the kidneys. They are used in treatment of hypertension, heart failure, and hepatic, renal, or pulmonary disease when salt and water retention has resulted in edema or ascites.
Furosemide (Lasix)
Increases excretion of water by interfering with chloride-binding cotransport system, which in turn inhibits sodium and chloride reabsorption in ascending loop of Henle and distal renal tubule. Dose must be individualized. Depending on response, administer at increments of 20-40 mg no sooner than 6-8 h after previous dose until desired diuresis occurs. When treating infants, titrate with 1 mg/kg/dose increments until satisfactory effect achieved.
Cardiac glycosides
Class Summary
These agents possess positive inotropic activity, which is mediated by inhibition of sodium-potassium adenosine triphosphatase (Na+/K+ ATPase). Also, cardiac glycosides reduce conductivity in the heart, particularly through the atrioventricular node, and therefore have a negative chronotropic effect. The cardiac glycosides have very similar pharmacological effects but differ considerably in their speed of onset and duration of action. They are used to slow the heart rate in supraventricular arrhythmias, especially atrial fibrillation, and also are administered in chronic heart failure.
Digoxin (Lanoxin, Lanoxicaps)
Cardiac glycoside with direct inotropic effects in addition to indirect effects on cardiovascular system. Acts directly on cardiac muscle, increasing myocardial systolic contractions. Its indirect actions result in increased carotid sinus nerve activity and enhanced sympathetic withdrawal for any given increase in mean arterial pressure.
Angiotensin-converting enzyme inhibitors
Class Summary
ACE inhibitors are beneficial in all stages of chronic heart failure. Dyspnea and exercise tolerance are improved. Unlike diuretics, studies demonstrate improvement of survival and reduced progression of mild or moderate heart failure to more severe stages. They have benefit in asymptomatic left ventricular dysfunction.
Enalapril (Vasotec)
Competitive inhibitor of ACE. Reduces angiotensin II levels, decreasing aldosterone secretion.
