Because of its protean clinical manifestations, diagnosis of acute myocarditis is quite limited unless proved by endomyocardial biospy. However endomyocardial biopsy is not always applicable in these patients. Neither there have been clear clinical criteria for diagnosis nor studies in regard to prognostic factors are available. We retrospectively evaluated clinical features and prognosis of patients with biopsy proven and/or clinically suspected acute myocarditis according to the status of the left ventricular systolic function.

Thirty six patients of acute myocarditis were enrolled. Eighteen patients were diagnosed by endomyocardial biopsy. We selected clinical diagnostic criteria for this disorder based on the clinicalpaboratory, echocardiographic and ECG findings obtained from this biopsy-proven acute myocarditis. Another 18 patients were selected matching these diagnostic criteria. We divided these thirty-six patients into two groups depending on the left ventricular systolic function : Group 1, EF(3)40(n=20); Group 2, EF<40(n=16). We compared clinical features and prognosis between the two groups.

1) The mean age of Group 1 was 39.7±13.6 years(male 12). The mean age of Group 2 was 34.0±14.7 years(male 11). Diastolic blood pressure at admission was significantly lower in Group 2 than in Group 1(82±10mmHg vs 67±15mmHg, p<0.05). 2) In transmitral Doppler findings, Group 1 had 4 patients(25%) with restrictive physiology while Group 2 had 12 patients(75%)(p<0.05). Global LV hypokinesia was more frequent in Group 2 than in Group 1(11/16(69%) vs 3/11(27%), p<(0.05). 3) During the follow up, there was no death in Group 1. But there were 5 deaths in Group 2. Three-year survival rate of Group 1 was better than that of Group 2(100% vs 75%, p<(0.05). In the eleven surviving patients in Group 2, seven patients(64%) showed recovery of the left ventricular systolic function.

In acute myocarditis, patients who presented with depressed systolic function showed lower diastolic blood pressure at admission, more frequent occurrence of restrictive physiology, more global hypokinesia rather than regional asynergy, and poorer prognosis.