Clinical and pathologic findings of myocarditis in two families with dilated cardiomyopathy.

The use of endomyocardial biopsy and gallium-67 scans in patients with dilated cardiomyopathy (DCM) has demonstrated the presence of myocardial inflammation in a subset of patients. A family with DCM was studied with endomyocardial biopsy and gallium-67 scanning; both identified the presence of myocarditis in the proband. Evaluation of histologic sections from decreased family members revealed myocarditis as the principal pathologic finding. This patient identified during life demonstrated a defect in suppressor lymphocytic function and improved with immunosuppressive therapy. A second family with DCM was discovered when postmortem examination of the proband and his father's heart showed myocarditis. A living sibling was identified with asymptomatic myocardial dysfunction. Longitudinal follow-up of surviving members of both families are in progress. This study indicates that thorough diagnostic evaluation of all patients with familial DCM should be pursued to identify subgroups with potentially treatable inflammation.