RESTRICTIVE CARDIOMYOPATHY

Increased myocardial stiffness impairs ventricular relaxation; diastolic ventricular pressures are elevated. Etiologies include infiltrative disease (amyloid, sarcoid, hemochromatosis, eosinophilic disorders), endomyocardial fibrosis, Fabry’s disease, and prior mediastinal irradiation.

Symptoms 

Are of heart failure, although right-sided heart failure often predominates, with peripheral edema and ascites.



Physical Examination 

Predominantly signs of right-sided heart failure: JVD, hepatomegaly, peripheral edema, murmur of tricuspid regurgitation. Left-sided S4 is common.

Laboratory ECG 

Low limb lead voltage, sinus tachycardia, ST-T-wave abnormalities.

CXR 

Mild LV enlargement.

Echocardiogram, CT, Cardiac MRI 

Bilateral atrial enlargement; increased ventricular thickness (“speckled pattern”) in infiltrative disease, especially amyloidosis. Systolic function is usually normal but may be mildly reduced.
Cardiac Catheterization Increased LV and RV diastolic pressures with “dip and plateau” pattern; RV biopsy useful in detecting infiltrative disease (rectal or fat pad biopsy useful in diagnosis of amyloidosis). Note: Must distinguish restrictive cardiomyopathy from constrictive pericarditis, which is surgically correctable. Thickening of pericardium in pericarditis usually apparent in CT or MRI.

Restrictive Cardiomyopathy TREATMENT

Salt restriction and diuretics ameliorate pulmonary and systemic congestion; digitalis is not indicated unless systolic function is impaired or atrial arrhythmias are present. Note: Increased sensitivity to digitalis in amyloidosis. Anticoagulation often indicated, particularly in pts with eosinophilic endomyocarditis. For specific therapy of hemochromatosis and sarcoidosis, see Chaps. 357 and 329, respectively, in HPIM-18.