An autopsy case of hypertrophic cardiomyopathy showing dilated cardiomyopathy-like features by serial ventriculography.

An autopsy case of hypertrophic obstructive cardiomyopathy (HOCM), in which the clinical features of dilated cardiomyopathy (DCM) developed after 10 years is described. Three serial left ventriculograms (LVG) and bi-ventriculograms (BVG) were performed during the 10-year follow-up. At the time of the first observation, the ECG revealed a giant negative T wave (GNT) in V5 (-1.5mV) and high voltage (SV1 + RV5 = 8.1mV). The LVG and BVG showed concentric left ventricular wall hypertrophy and a pressure gradient in the left ventricular out-flow tract. However, follow-up studies disclosed resolution of the GNT with decreased high voltage. All wall thicknesses and the ejection fraction were significantly decreased and the wall motion was reduced serially. These findings were consistent with the clinical profile of DCM. At autopsy, the heart weighed 610 g and showed dilated change of the left ventricular cavity. Significant myocardial fibrosis, bizarre myocardial hypertrophy with disorganization (BMHD) and severe narrowing of the intramural small arteries due to intimal thickening were found in the left ventricular wall, especially in the anterior and interventricular septal wall. This autopsy case suggests that some cases of HCM, with serial disappearance of the deep negative T wave and high voltage, deteriorate to the clinical profile of DCM.