cardiovascular disorders
Restrictive Cardiomyopathy
Key Points
In restrictive cardiomyopathy, endocardial thickening or myocardial infiltration leads to a rigid, noncompliant ventricle and thus diastolic dysfunction; systolic function is normal until late in the disease. Sometimes, valvular tissue or the conduction system is involved, causing valvular regurgitation or heart block and arrhythmias. Etiology is usually unknown, but some cases are caused by potentially treatable disorders, including amyloidosis, hemochromatosis, or sarcoidosis. Diagnosis is by echocardiography plus testing for cause. Treatment is often unsatisfactory unless the cause can be addressed; diuretics may benefit patients with edema or pulmonary vascular congestion but must be used cautiously to avoid lowering preload. Standard treatments for dilated cardiomyopathy (eg, ACE inhibitors,digoxin, beta-blockers) are poorly tolerated in restrictive disease. 