Myocardial infarction in childhood: clinical analysis of 17 cases and medium term follow up of survivors.

Between 1979 and 1989 17 patients aged two months to 12 years with acute myocardial infarction of any cause (other than after cardiac surgery) were seen at a children's hospital. Eight died from three days to three years after diagnosis (overall mortality 47%). The nine survivors, now aged 2-17 years, have been followed for one to 10 years (mean follow up five years) after infarction. The commonest causes of myocardial infarction in this series were anomalous origin of left coronary artery from the pulmonary artery (six patients (35%] and Kawasaki disease (five patients (27%]. The main symptoms of acute myocardial infarction were dyspnoea, vomiting, and difficulty feeding. Diagnosis was made in all patients by electrocardiography and confirmed by echocardiography, cardiac catheterisation, or at operation. All survivors were symptom free with excellent exercise capacity. The left ventricular ejection fraction in survivors ranged from 21% to 66%, and only one child was on regular cardiac medications. There were no cases of late sudden death. Twenty four hour Holter monitoring performed on survivors was normal (seven) or showed minor abnormalities only (one), suggesting that serious arrhythmia is rare after paediatric myocardial infarction. Myocardial infarction in children had a high early mortality; however, the incidence of serious arrhythmia was low in the survivors, who had a good exercise tolerance even when the left ventricular ejection fraction was low.