Cardiomyopathy, Restrictive

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