[Histopathological analysis of cellular infiltration in 42 autopsied cases of dilated cardiomyopathy].

Myocarditis is a possible cause of dilated cardiomyopathy (DCM), but criteria for cell infiltration in autopsy cases have not been established. The significance of cell infiltration was evaluated in 42 autopsied cases of DCM which met the diagnostic criteria of the Ministry of Health and Welfare, among 1,700 serial autopsy cases at the National Cardiovascular Center, using the W.D. Edwards and Dallas criteria. Microscopic examinations used sections of the heart along the short axis at the upper one-third and lower one-third levels. Infiltration of small round cells was divided into 3 layers: the epicardial layer, myocardial layer and endocardial layer. Three types of fibrosis were classified: interstitial, focal (less than 1 cm in greatest diameter), and massive (equal to or exceeding 1 cm in greatest diameter). The mean age at death was 50.3 years, but female patients died earlier than male patients. The period of congestive heart failure was 5 years; with a family history of cardiomyopathy in 10% of all patients. The subgroup which fulfilled both criteria consisted of 12 patients (28.6%; positive group). The other subgroup consisted of 30 patients (71.4%; negative group). Cell infiltration tended to be greater in the epicardial layer and less in the endocardial layer. This trend was more prominent in the positive group. Interstitial fibrosis was seen in 73.8% of all patients. Clinically, the positive group was younger at death with higher serum LDH values and lower % fractional shortening on echocardiograms, all statistically significant. Other trends were thinner left ventricular walls, smaller left ventricular cavities and lower cardiac weights in the positive group.(ABSTRACT TRUNCATED AT 250 WORDS)