Idiopathic myocardial hypertrophy

The records of twenty-one patients with idiopathic myocardial hypertrophy observed during a period of five years were reviewed. On the basis of their dominant clinical course these cases could be classified into three groups: (1) severe intractable congestive heart failure; (2) minimal to moderate congestive heart failure; (3) symptoms referable primarily to an associated portal cirrhosis. The cause of this disorder remains obscure. However, in the first two groups there is speculation that some of the cases might be congenital in origin.The clinical features were related to the underlying congestive heart failure and to pulmonary and systemic emboli which at times dominated the picture. The electrocardiogram in typical cases showed left ventricular hypertrophy or intraventricular conduction disturbances, normal or left axis deviation and a characteristic biphasic P wave in lead V₁. Roentgenograms of the chest showed globular cardiac enlargement. Cardiac catheterization and ballistocardiographic data were consistent with congestive heart failure.Histologic examination of the heart revealed myocardial hypertrophy usually associated with focal interstitial fibrosis. Over one half of cases undergoing necropsy revealed intramural thrombi in the left ventricle.The possible etiologic factors and the differential diagnosis of this condition were considered. The diagnosis of idiopathic myocardial hypertrophy is suggested by the presence of cardiomegaly in relatively young normotensive adults with gallop sounds, absent organic murmurs and electrocardiographic criteria of both left atrial and left ventricular enlargement irrespective of the presence or absence of congestive phenomena.