The conduction system in dilated cardiomyopathy. A pathomorphological study.

A semi-serial histopathological study was conducted into the cardiac conduction system (CCS) of 14 autopsy subjects with dilated idiopathic cardiomyopathy (DIC). Clinical and pathomorphological data corresponding to this disease were compiled by Hudson's criteria. The most important histopathological findings were the frequency of vascular changes observed in small-size arteries that irrigate the sino-atrial and atrioventricular nodes, the bundle of His, the origin of both bundle branches, and the upper portion of the ventricular septum. Vascular changes, although unequal and inconstant, together with regressive and inflammatory features were observed in the majority of specimens. Also, good correlations were found to exist between electrocardiographic data and the direct cause of death, the intensity and/or extension of lesions did not correlate with the duration of the disease. While the vascular lesions might have been the first pathological changes, their variability and inconsistency suggested that more than one aetiological factors were involved in this type of cardiomyopathy.