[Acute myocarditis with severe cardiac dysfunction in the pediatric population. The evolution and differential characteristics with respect to adult myocarditis].

Abstract

AIMS: The aim of our study was to assess the spontaneous outcome of acute myocarditis associated with severe cardiac dysfunction in children, as well as to compare these features with those occurring in adult patients. METHODS: Fifty patients consecutively diagnosed of acute myocarditis during the last 7 years in our hospital were studied; 15 patients were children younger than 14 years, and 35 were adults. Immunosuppressive therapy was not used in any patient. RESULTS: Mean age was 2 +/- 3 years in children, ranging from 2 months to 12 years. One patient required temporary pacing for a third-degree atrioventricular block, while the remaining 14 children had severe congestive heart failure, with a left ventricular ejection fraction of 30 +/- 12% (16 to 44%). After a mean follow-up of 21 +/- 26 months, only 3 children died, at 1, 4 and 10 months after the initial diagnosis. Death was sudden in all 3 patients. Left ventricular ejection fraction rose to 45 +/- 14% at 1 month after diagnosis, and to 58 +/- 15% at the end of follow-up. Unfavorable evolution (death or evolution to chronic dilated cardiomyopathy, with a left ventricular ejection fraction < 45%) occurred in 6 children (40%) at 1 month after diagnosis and in only 4 (25%) at the end of follow-up. The 9 children with 1-month favorable outcome were alive and had an ejection fraction > 45% at long-term, while only 2 of the 6 children with 1-month unfavorable outcome were alive and had an ejection fraction > 45% at long-term. Only the 3 children who died had an ejection fraction < 30% at 1-month. Favorable outcome was more frequent in children that in adult patients with acute myocarditis (75% versus 46%). CONCLUSIONS: The outcome of acute myocarditis with severe cardiac dysfunction was favorable in a majority of pediatric patients; this favorable evolution was less frequent in adults. Patients in whom left ventricular ejection fraction did not increase at short-term had a higher risk of death, and they should probably be considered for heart transplantation.