Comparative study of dilated cardiomyopathy and specific heart muscle diseases from pathophysiological aspects--echocardiographic observation.

To investigate the causative factors of dilated cardiomyopathy (DCM), 29 DCM patients were echocardiographically and histopathologically compared with 17 patients with specific heart muscle diseases mimicking DCM. These consisted of 6 cases of myocarditis and 11 of alcoholic heart muscle disease. Myocarditis patients had less dilation of the left ventricle, more marked segmental wall motion abnormality on admission and more extensive myocardial fibrosis than patients with alcoholic heart muscle disease and DCM. Four myocarditis patients died of congestive heart failure before showing a marked dilatation of the left ventricle. The alcoholic heart muscle disease patients revealed diffuse wall motion abnormality on admission. Out of these 8 patients who had abstained showed amelioration. However, in 3 who had not abstained, both wall motion abnormality and dilatation of the left ventricle markedly progressed and 2 died of congestive heart failure. Although the DCM patients as a group showed deterioration throughout the follow-up period, individual patients revealed a variety of echocardiographic and pathological findings, which led to the regrouping of 29 patients with DCM into 2 subgroups. One group had characteristic features similar to these of patients with myocarditis, and the other had characteristics similar to these of patients with alcoholic heart muscle disease. These findings suggested that different causative factors might coexist in DCM.