Myocardial inflammatory cell infiltrates in cases of dilated cardiomyopathy as a determinant of outcome following partial left ventriculectomy

Partial left ventriculectomy (PLV) can be used to treat refractory congesti ve heart failure caused by dilated cardiomyopathy (DCM). In order to unders tand the relationship between the underlying myocardial injury and early cl inical outcomes after PLV, histopathologic, immunohistochemical and virolog ic studies of the resected myocardium were performed. The posterolateral le ft ventricular walls from 27 patients with idiopathic DCM were examined. Ca rdiomyocyte diameter, degree of myocardial fibrosis, degree of cardiomyocyt e degeneration, and degree of inflammatory cell infiltration were compared with mortality rates. Polymerase chain reaction was performed to detect ent erovirus genome in the myocardium. Some patients had inflammatory cell infi ltrates with focal accumulations of lymphocytes and macrophages, including both cytotoxic/suppressor T-cells and helper/inducer T-cells. The number of inflammatory cells (activated lymphocytes plus macrophages/mm(2)) was sign ificantly greater in patients who died of cardiac insufficiency after surge ry (27.8 +/-5.7; n=7) than in the survivors (11.1 +/-2.5; n=15). There was no significant difference in the degree of myocardial fibrosis, cardiomyocy te diameter or degree of cardiomyocyte degeneration between the 2 groups. E nterovirus genome was detected in the myocardium of 9 (38%) of 24 patients examined and 5 of these enterovirus-positive hearts had severe inflammatory cell infiltrates (37.9 +/-2.5/mm(2)). Early survival in patients undergoin g PLV for DCM is significantly affected by the degree of myocardial inflamm ation, so patients with more severe or ongoing inflammation may have poor c linical outcomes. Chronic myocarditis may play an important role in the eti ology and pathophysiology of idiopathic DCM.