Cell infiltration caused deterioration in the prognosis of patients with clinical diagnosis of dilated cardiomyopathy (DCM): application of biopsy criteria of myocarditis to 42 autopsy cases.

Many investigators consider viral myocarditis as an important cause of a dilated cardiomyopathy (DCM)-like state. In assessing myocarditis in endomyocardial biopsy samples, two sets of criteria, i.e., the Edwards and the Dallas criteria, are employed. However, no criteria have been established for cell infiltration in autopsy cases, nor have biopsy criteria for myocarditis been applied in autopsy cases. We analyzed the clinicopathologic features and small round cell infiltration in 42 autopsy cases whose clinical diagnoses were DCM, employing both the Edwards and the Dallas criteria. Of the 42 cases, 12 (29%) showed positive results for both sets of criteria. These 12 positive patients were proven to have myocarditis by autopsy and they showed more severe clinical features than 30 cases with negative cell infiltration.