Restrictive Cardiomyopathy Medication

Treatment of restrictive cardiomyopathy (RCM) is symptomatic. Treatment goals include decreasing systemic and pulmonary congestion, lowering ventricular filling pressure, augmenting systolic pump function, and reducing the risk for embolism.^[9]

Class Summary

Diuretics are used to reduce pulmonary and systemic congestion. Symptomatic treatment may improve symptoms of venous congestion through elimination of retained fluid and preload reduction. Initiate therapy with a low dosage because relatively high levels of ventricular filling pressure must be maintained for adequate diastolic filling.

Hydrochlorothiazide (Microzide)

Hydrochlorothiazide inhibits reabsorption of sodium in distal tubules, causing increased excretion of sodium and water as well as potassium and hydrogen ions.

Furosemide (Lasix)

Furosemide increases excretion of water by interfering with the chloride-binding cotransport system, which in turn inhibits sodium and chloride reabsorption in the ascending loop of Henle and the distal renal tubule. The dose must be individualized to the patient. Depending on response, administer furosemide at increments of 20-40 mg no sooner than 6-8 hours after the previous dose until the desired diuresis occurs. When treating infants, titrate with 1-mg/kg/dose increments until a satisfactory effect is achieved.

Class Summary

Nitrates are used to reduce preload in diastolic dysfunction.

Nitroglycerin PO (Nitrostat, Nitro-Dur, Nitro-Time, Nitro-Bid)

Nitroglycerin causes relaxation of vascular smooth muscle by stimulating intracellular cyclic guanosine monophosphate production. The result is a decrease in blood pressure. This agent is available as lingual pump spray, sublingual tablets, oral tablets, patches, and ointments.

Class Summary

Cardiac glycosides are used to treat atrial fibrillation and systolic dysfunction in RCM. Digitalis and other positive inotropic agents generally are not indicated unless systolic pump function and contractility are impaired. Digitalis must be used with caution in patients with amyloid cardiomyopathy; such patients may be digoxin sensitive (arrhythmogenic) because of amyloid fibril binding of digoxin.

Digoxin (Lanoxin)

Digoxin is a cardiac glycoside with direct inotropic effects in addition to indirect effects on the cardiovascular system. It acts directly on cardiac muscle, increasing myocardial systolic contractions. Indirect actions result in increased carotid sinus nerve activity and enhanced sympathetic withdrawal for any given increase in mean arterial pressure.

Class Summary

Vasodilators are used to reduce ventricular filling pressure. Avoid excessive decrease in preload and diastolic filling.

Hydralazine

Hydralazine decreases systemic resistance through direct vasodilation of arterioles.

Isosorbide dinitrate and hydralazine (BiDil)

A fixed-dose combination of isosorbide dinitrate (20 mg/tab), a vasodilator with effects on both arteries and veins, and hydralazine (37.5 mg/tab), a predominantly arterial vasodilator, is indicated for heart failure in blacks, in part on the basis of results from the African American Heart Failure Trial.

Two previous trials in the general population of patients with severe heart failure found no benefit but suggested benefit in patients who are black. In comparison with placebo, this combination showed a 43% reduction in mortality, a 39% decrease in hospitalization rate, and a decrease in symptoms from heart failure among blacks.

Class Summary

Anticoagulants are used to prevent embolism from ventricular thrombus.

Warfarin (Coumadin)

Warfarin interferes with hepatic synthesis of vitamin K–dependent coagulation factors. It is used for prophylaxis and treatment of venous thrombosis, pulmonary embolism, and thromboembolic disorders.

Heparin

Heparin augments the activity of antithrombin III and prevents conversion of fibrinogen to fibrin. It does not actively lyse but is able to inhibit further thrombogenesis. Heparin prevents reaccumulation of clot after spontaneous fibrinolysis.