Morphological features of hypertrophic cardiomyopathy with congestive heart failure and a small left ventricular cavity.

To clarify the morphologic basis of marked congestive heart failure in cases of hypertrophic cardiomyopathy with a small left ventricular cavity, the size of myocytes, the extent of myocardial fiber disarray and fibrosis were quantitatively evaluated in two autopsied cases. Compared with the control hypertrophic cardiomyopathy, both cases had larger myocytes and less fibrosis, and one of them had markedly extensive myocardial fiber disarray. Probably, the hypertrophy of the myocytes or myocardial fiber disarray or both rather than myocardial fibrosis are important in the pathogenesis of severe congestive heart failure in these cases.