[Idiopathic restrictive cardiomyopathy: clinical, hemodynamic, histologic and prognostic profile]

Idiopathic restrictive cardiomyopathy is a rare myocardial disease characterized by restrictive physiology without a specific histologic basis. To assess its clinical, hemodynamic, morphologic and prognostic details we retrospectively evaluated all the patients hospitalized in our Institute from 1974 to 1988. Nine patients, aged 42 +/- 16 years, M/F ratio = 0.29, who represent 64% of all the restrictive myocardial diseases biopsied were identified. Severe cardiac heart failure (3-4 NYHA) and arrhythmias (ventricular and supraventricular) were extremely common. The electrocardiogram showed several non specific signs: low voltage of QRS in peripheral leads (4/7), pseudo-infarctional aspects (3/7), mono or biventricular hypertrophy (3/7) disturbance of ventricular conduction (3/7), aspecific abnormalities of ventricular repolarization (3/7). All patients showed a prolonged QTc. M-mode and 2-dimensional echocardiography demonstrated in 6 cases biatrial enlargement, normal or slightly enlarged ventricles, normal or moderately depressed fractional shortening; biventricular concentric hypertrophy was detected in 3 cases, asymmetrical septal hypertrophy in 1. Five patients showed pericardial effusion. Cardiac catheterization disclosed an increase of left and right ventricular end-diastolic pressures (8/8) with a dip-plateau pattern and/or characteristic W waveform in the atrial pressure tracing (9/9). Passive pulmonary hypertension was detected in 6/9 cases. The cardiac index was decreased in 4/8 cases. Left ventricular angiography showed mitral regurgitation in 5/8 patients, tricuspidal in 5/8. Ejection fraction was decreased in 3/8 cases. Endomyocardial biopsy showed interstitial fibrosis (8/9), cellular hypertrophy and/or nuclear alterations (7/9), slight endocardial thickening (2/9). At a mean follow-up of 22 +/- 15 months 3 patients died and 2 underwent heart transplantation. In conclusion idiopathic restrictive cardiomyopathy is one of the most frequent forms of restrictive myocardial diseases in our geographic area. Severe congestive heart failure and arrhythmias are extremely common. The disease can be suspected by clinical, electrocardiographic and echocardiographic features, but the final diagnosis requires cardiac catheterization and endomyocardial biopsy. Prognosis is severe and heart transplantation must be considered in the cases with severe heart failure.