Five-year follow-up study of cases suggestive of acute myocarditis

Abstract

Ninety consecutive cases of acute infectious disease attended by signs highly suggestive of myocarditis (“presumptive myocarditis group”) were followed up after 5 years, with examinations by the methods previously employed, namely, electrocardiography at rest, during exercise, and on orthostatic tests, heart roentgenography, and functional tests for determination of the physical working capacity. Identical examinations were carried out in 26 similar cases in which, 5 years previously, there had been signs possibly suggestive of myocarditis (“dubious myocarditis group”). Finally, the investigation included 34 cases of acute infectious disease in which, at the onset 5 years earlier, there had been no signs of cardiac involvement (controls). Approximately 25 per cent of the 90 patients in the first group reported subjective symptoms—fatigue, dyspnea, impaired physical condition, precordial pain—as compared to 75 per cent during prior convalescence. The corresponding incidence in the control group was about 5 per cent. At follow-up, about 25 per cent were found to have elevated antistreptolysin titers and/or erythrocyte sedimentation rates, the incidence being the same in the control group. Suspect phonocardiographic findings were recorded in 23 per cent (as against 3 per cent in the controls), but in no case were presystolic or diastolic murmurs noted. The resting ECGs were abnormal in 19 per cent, the exercise ECGs in 30 per cent, and the orthostatic ECGs in 10 per cent (0.6 and 12 per cent, respectively, for the controls). Sixty per cent of all abnormal ECGs were recorded either during or after exercise. The majority of electrocardiographic abnormalities were referable to cases of aseptic meningitis, rheumatic fever, and scarlet fever. In most cases the abnormalities involved the terminal complex. In addition to these abnormalities, some cases of rheumatic fever exhibited atrioventricular conduction block; and others, disturbances in rhythm. The working capacity was abnormally low in 41 per cent of all cases of presumptive myocarditis (and in 3 per cent of the controls), irrespective of the nature of the initial infectious disease. The heart volume was enlarged in 20 per cent, possibly with a somewhat higher incidence for patients with aseptic meningitis and rheumatic fever than for those with other infectious diseases. No case of enlargement of the heart was found in the control group. Abnormal findings were frequently interrelated; in particular, there was a high incidence of enlarged heart volume coincident with a low working capacity. The incidences of abnormal findings were much the same in the “dubious myocarditis” group, except for the orthostatic ECGs, which showed abnormalities in 27 per cent, in comparison with about 10 per cent in the other two groups. Abnormal findings were recorded in a few cases in the control series. Only in one or two patients were there signs that myocardial lesions had developed during the past 5 years. To sum up, the over-all results of this 5-year follow-up study of 90 cases suggestive of postinfectious myocarditis (and compared with relevant control series) indicate that about 20 per cent of the patients still had subjective symptoms, some 15 to 20 per cent had abnormal ECGs, about 30 per cent had abnormal exercise ECGs, approximately 40 per cent had low working capacities, and 15 to 20 per cent had enlarged heart volumes.