Objective: To evaluate clinical course, laboratory and echocardiographic findings in infants with severe left ventricular (LV) failure and structurally normal heart.
Methods and patients: Inclusion criteria in this retrospective study were age at admission < 1 year, severe LV dysfunction, and absence of congenital or metabolic heart disease or primary dysrhythmias.
Results: 15 infants (7 girls and 8 boys) hospitalized between years 1997 and 2015 at median age 5 months (12 days - 11 months) were identified. SF and EF were at admission 10 ± 5 % and 23 ± 11 % (mean ± SD), respectively. Two patients with severe circulatory failure died within 48 hours and were excluded from further study. Two patients with intractable heart failure died 4 and 8 months after initial presentation. Out of 13 early survivors 8 patients received immunoglobulins and 6 were treated with steroids and/or cyclosporine for the next 4 - 10 (median 7) months. Pulmonary artery banding to improve left and right ventricular interaction was performed in 2 patients and 5 patients were temporarily listed for heart transplantation. Troponin I and/or CK-MB mass were abnormally increased in 10 patients (Group A) and normal in 5 patients (Group B). Myocardial biopsy was performed in 4 patients in Group A (confirmed active or borderline myocarditis in all) and in 1 patient in Group B (borderline myocarditis). At last examination of 13 early survivors (median 23, range 3 to 147 months after discharge) LV function normalized in 6/9 patients in Group A and remained abnormal in all 4 patients in Group B.
Conclusion: Infants with severe LV failure and increased myocardial enzymes suffer most likely from ongoing myocarditis and their probability of heart function recovery is high. Those without myolysis apparently progressed into irreversible dilated cardiomyopathy with a rather poor prognosis.