Morphological changes in the association of hypertrophic cardiomyopathy and disorder of conduction system causing sudden death: report of two cases

Abstract

Cardiovasculary diseases constitute the majority of sudden and unexpected deaths. The most common cause of sudden deaths due to cardiac reasons is coronary atherosclerosis. Sudden deaths due to disorders of conduction system are rare. We herein present morphological changes associated with disorders of conduction system, which were determined to have caused death in two male cases aged 20 and 30 years. Case 1 was 20- year-old and had died suddenly during physical activity. No macroscopic pathology except for cardiomegaly was determined at the autopsy. Histopathological examination revealed fibrosis and fatty alteration/infiltration in conduction system, and myocardial hypertrophy. The cause of death was determined as sudden circulatory failure resulting from hypertrophic cardiomyopathy and conduction system disorder. Case 2 was 30-yearold and had died when brought to hospital after deteriorating suddenly six hours after a heavy exercise. Only cardiomegaly was determined macroscopically at the autopsy. Histopathological examination revealed fibrosis and fatty alteration/infiltration in conduction system, and degenerative changes and fibrosis in fibrils of myocardium. The cause of death was determined as the same as in the Case 1. When myocardial hypertrophy is prominent at autopsy, the possibility of cardiac conduction system disorder should be considered in addition to hypertrophic cardiomyopathy. Considering that obvious morphological changes due to conduction system disorder can not be macroscopically determined at the autopsy in sudden young deaths, detailed sampling of cardiac conduction system for histopathological examination is especially important in these cases.