Sections View Full Chapter Figures Tables Videos Full Chapter Figures Tables Videos Supplementary Content ++ Key Features ++ Rare; accounts for < 5% of all cases of cardiomyopathy Cause is usually idiopathic but can be familial or secondary to an infiltrative process (eg, amyloidosis) ++ Clinical Findings ++ Exercise intolerance Fatigue Chest pain Orthopnea Prominent S4 Jugular venous distention Signs of congestive heart failure as a consequence of diastolic dysfunction in the setting of preserved systolic function Left ventricle is more severely affected than the right ventricle, but the right ventricle is also affected in most cases resulting in signs and symptoms consistent with biventricular congestion ++ Diagnosis ++ Electrocardiography Demonstrates marked right and left atrial enlargement with normal ventricular voltages ST-T–wave abnormalities including a prolonged QTc interval may be present Echocardiography Presence of normal-sized ventricles with normal systolic function and massively dilated atria confirm diagnosis Cardiac MRI is useful in ruling out pericardial abnormalities (restrictive or constrictive pericarditis) and infiltrative disorders ++ Treatment ++ Anticongestive therapy is used for symptomatic relief GET ACCESS TO THIS RESOURCE Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth Get Free Access Through Your Institution Contact your institution's library to ask if they subscribe to McGraw-Hill Medical Products. Access My Subscription GET ACCESS TO THIS RESOURCE Subscription Options Pay Per View Timed Access to all of AccessPediatrics 24 Hour $34.95 (USD) Buy Now 48 Hour $54.95 (USD) Buy Now Best Value AccessPediatrics Full Site: One-Year Individual Subscription $595 USD Buy Now View All Subscription Options