Medication Summary
Treatment of restrictive cardiomyopathy (RCM) is symptomatic. Treatment goals include reducing systemic and pulmonary congestion, lowering ventricular filling pressure, augmenting systolic pump function, and reducing the risk for embolism. [19]
Diuretics
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 dose because relatively high levels of ventricular filling pressure must be maintained for adequate diastolic filling.
Hydrochlorothiazide (Microzide)
Hydrochlorothiazide inhibits reabsorption of sodium in the distal tubules, causing increased excretion of sodium and water as well as potassium and hydrogen ions.
Furosemide (Lasix)
Furosemide increases the 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.
Nitrates
Class Summary
Nitrates are used to reduce preload in diastolic dysfunction.
Nitroglycerin PO
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.
Beta-Blockers, Alpha Activity
Class Summary
May improve symptoms by increasing left ventricular filling time, improving ventricular relaxation, and decreasing compensatory sympathetic stimulation.
Carvedilol (Coreg, Coreg CR)
Nonselective beta- and alpha-adrenergic blocker. Also has antioxidant properties. Does not appear to have intrinsic sympathomimetic activity. May reduce cardiac output and decrease peripheral vascular resistance.
Calcium Channel Blockers
Class Summary
May improve symptoms by increasing left ventricular filling time, improving ventricular relaxation, and decreasing compensatory sympathetic stimulation.
Verapamil (Calan, Isoptin)
Nondihydropyridine calcium-channel blocker that inhibits extracellular calcium ion influx across membranes of myocardial cells and vascular smooth muscle cells, resulting in inhibition of cardiac and vascular smooth muscle contraction and thereby dilating main coronary and systemic arteries.
Diltiazem (Cardizem, Cardizem CD, Dilacor Tiazac)
Nondihydropyridine calcium-channel blocker that inhibits extracellular calcium ion influx across membranes of myocardial cells and vascular smooth muscle cells, resulting in inhibition of cardiac and vascular smooth muscle contraction and thereby dilating main coronary and systemic arteries.
Vasodilators
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/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), which is a predominantly arterial vasodilator. Based on the results of the African American Heart Failure Trial, isosorbide dinitrate/hydralazine is indicated for heart failure in black patients.
Two previous trials in the general population of patients with severe heart failure found no benefit, but it suggested a 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 black patients.
Anticoagulants, Cardiovascular
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.
Inotropic Agents
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.
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Restrictive cardiomyopathy. Axial double inversion-recovery magnetic resonance image of the heart in a 30-year-old woman with sarcoidosis demonstrates a normal pericardium.
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Restrictive cardiomyopathy. Axial contrast-enhanced computed tomography scan through the heart (same patient as in the previous image) shows a thin pericardium without calcification. Note the cardiophrenic and internal mammary lymph nodes. The patient had extensive mediastinal and hilar adenopathy, as well as interstitial lung changes.
Tables
Clinical Features |
Constrictive Pericarditis |
Restrictive Cardiomyopathy |
History |
Prior history of pericarditis or condition that causes pericardial disease |
History of systemic disease (eg, amyloidosis, hemochromatosis) |
General examination |
… |
Peripheral stigmata of systemic disease |
Systemic examination - Heart sounds |
Pericardial knock, high-frequency sound |
Presence of loud diastolic filling sound S3, Low-frequency sound |
Murmurs |
No murmurs |
Murmurs of mitral and tricuspid insufficiency |
Prior chest radiograph |
Pericardial calcification |
Normal results of prior chest radiograph |
Investigation |
Constrictive Pericarditis |
Restrictive Cardiomyopathy |
Chest radiograph |
Pericardial calcification |
Atrial dilation causing increased cardiothoracic ratio; normal ventricular size |
CT scanning/MRI |
Pericardial thickening |
No pericardial thickening |
Echocardiography |
Normal-sized ventricles and atria; pericardial effusion may be observed |
Nondilated, normally contracting, nonhypertrophied ventricles and marked dilation of both atria |
Doppler flow velocities on echocardiography |
Respiratory changes (ie, decreased peak transmitral diastolic flow) during inspiration; equalization of the right- and left-sided filling pressures |
No respiratory changes; greater elevation in the left-sided filling pressures |
Catheterization hemodynamics: 1) RVSP 2) RVEDP:RVSP ratio 3) RVEDP/LVEDP equalization |
1) = 50 mm Hg 2) = 0.33 3) = 5-mm Hg difference |
1) = 50 mm Hg 2) = 0.33 3) = 5-mm Hg difference |
Cardiac biopsy |
Normal myocardium |
Often diagnostic, showing abnormal myocardium |
CT = computed tomography; LVEDP = left ventricular end-diastolic pressure; MRI = magnetic resonance imaging; RVEDP = right ventricular end-diastolic pressure; RVSP = right ventricular systolic pressure. |
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