Endomyocardial biopsy findings in cases with pericarditis or perimyocarditis.

In order to determine the presence or absence of myocarditis in cases with viral or idiopathic pericarditis, a study was conducted as one of our series on endomyocardial biopsy. There were two groups of patients, pericarditis cases (n = 8), and patients with perimyocarditis (n = 6). In the former group, it was confirmed that cardiac sarcoplasmic enzymes were not released during the acute stage of the disease. In the latter, there was positive evidence of the enzyme release. Also, employing our method of categorizing the possibility of myocarditis at the histopathological level, we found that the category 'highly suggestive' of myocarditis was absent in all eight cases with pericarditis. However, in cases with perimyocarditis, this category was assigned in four out of six cases (67%), indicating a high incidence. The category, 'slightly suggestive', was seen in three cases of the former (38%) and two cases of the latter group (33%). It is concluded that in patients with pericarditis, the release of cardiac sarcoplasmic enzyme is an important diagnostic element in the diagnosis of perimyocarditis even if the clinical features reveal a predominance of pericarditis. In patients with perimyocarditis, progression to residual cardiac disease, such as conduction disturbance or congestive heart failure, is likely.