MORPHOLOGIC SPECTRUM OF PRIMARY RESTRICTIVE CARDIOMYOPATHY

A restrictive hemodynamic profile with left ventricular (LV) end-diast olic volume <100 ml/m(2) and LV end-diastolic pressure >18 mm Hg, in t he absence of endomyocardial, pericardial, and specific cardiomyopathy , is a peculiar feature of primary restrictive cardiomyopathy. From 19 85 to 1994, 7 hearts of patients who met the above hemodynamic criteri a and underwent endomyocardial biopsy because of heart failure, were s tudied through gross (5 cardiectomies and 2 autopsies), histologic, an d electron microscopic investigations. Ages ranged from 9 to 48 years (mean age 29 +/- 13). Four patients (57%) had a positive family histor y: 2 for hypertrophic and 2 for restrictive cardiomyopathy. Three patt erns were identified in the 7 hearts: (1) pore restrictive form in 4 c ases with mass/volume ratio 1.2 +/- 0.5 g/ml, ejection fraction 58 +/- 5%, LV end-diastolic volume 67.5 +/- 12.6 ml/m(2), LV end-diastolic p ressure 26.7 +/- 3.5 mm Hg; (2) hypertrophic-restrictive form in 2 cas es with mass/volume ratio 1.5 +/- 0.07 g/ml, ejection fraction 62 +/- 1%, LV end-diastolic volume 69 +/- 10 ml/m(2), LV end-diastolic pressu re 30 +/- 7 mm Hg; and (3) mildly dilated restrictive form in 1 case w ith mass/volume ratio 0.9 g/ml, ejection fraction 25%, LV end-diastoli c volume 98 ml/m(2), LV end-diastolic pressure 40 mm Hg. Histology and electron microscopy disclosed myocardial and myofibrillar disarray an d endoperimysial interstitial fibrosis in each pattern. The familial f orms suggest the presence of a genetic abnormality. Primary restrictiv e cardiomyopathy may present with or without hypertrophy and shares si milar microscopic pictures with hypertrophic cardiomyopathy. The 2 ent ities may represent a different phenotypic expression of the same gene tic disease. (C) 1997 by Excerpta Medica, Inc.