CLINICOPATHOLOGICAL CHARACTERISTICS OF ELDERLY PATIENTS WITH PERSISTENT ST SEGMENT ELEVATION AND INVERTED-T WAVES - EVIDENCE OF INSIDIOUS OR HEALED MYOCARDITIS

Objectives. We sought to clarify the clinicopathologic characteristics of insidious or healed myocarditis in the elderly. Background. Myocar ditis is the cause of unexplained congestive heart failure and dilated cardiomyopathy. However, acute myocarditis of the Fiedler type is rar e, and the incidence and implication of insidious or healed myocarditi s in the elderly are not yet known. Methods. In an autopsy study of 3, 000 patients aged greater than or equal to 60 years, there were 12 (0. 4%) with insidious or healed myocarditis, showing extensive and circum ferential fibrosis and scattered lymphocytic infiltration of both vent ricular walls without acute necrosis of the myocardial fibers. Results . Unexplained congestive heart failure was found in seven cases. In al l cases, electrocardiography had demonstrated upward elevation of the ST segment and inverted T waves for durations ranging from 1 month to 12.7 years (mean 5.7 years). Mean (+/-SD) heart might was 338 +/- 81 g (range 220 to 470). In nine eases, fibrous lesions, which were scatte red but extensive and circumferential, were located in the subepicardi al and middle layers of the left ventricle. In the remaining three cas es, the fibrous lesions were located predominantly in the subepicardia l and middle layers, but the subendocardial layer was also locally inv olved. Fibrous lesions of the right ventricle were predominant in the subepicardial layer and involved the subendocardial layer in four case s. Scattered lymphocytic infiltration was found in the fibrous lesions . Conclusions. In more than half of the aged cases with insidious or h ealed myocarditis, unexplained congestive heart failure was also prese nt. Fibrous lesions due to myocarditis were located predominantly in t he subepicardial and middle layers and led to persistent upward elevat ion of the ST segment and inverted T waves.