Sudden cardiac death in children cardiomyopathy, a French study

Abstract

Cardiomyopathies in children are rare and heterogeneous diseases whose rhythmic risk is difficult to stratify. (1) To describe the patients who presented with severe arrhythmias in DCM and HCM, (2) to highlight risk factors, (3) to calculate the HCM Risk-Kids in our HCM patients. We set up a retrospective and multicenter observational cohort in the Nord-Pas-de-Calais region in France from 2009 to 2019 in 11 medical centers. We included 224 pediatric patients (diagnosis ≤ 18 years) followed for cardiomyopathy including 72 hypertrophic cardiomyopathies (HCM), 69 dilated cardiomyopathies (DMC), 12 Non-Compactions of the left ventricle, 9 restrictives cardiomyopathies and 63 myocarditis without dilation or hypokinetic cardiomyopathies without expansion (and 84 others cardiomyopathies). In our DMC population, event-free survival (sudden recovered death or heart transplant) is 70% at 5 years. Among the 69 DCM, we report only 3 sudden deaths recovered: one in a patient with laminopathy, One in a patient with Barth syndrome and one in a context of acute heart failure. In our HCM cohort, event-free survival was 82% at 5 years. Of the 72 HCM, 11 presented with sudden death. The HCM Risk-Kids was calculated at 6.2% on average. Age at diagnosis > 9 years increased by 5.3 times the rhythmic risk (P = 0.023). The presence of a genetic mutation also seemed to be associated with an increased risk, but this result was not significant (P = 0.059). An HCM Risk-kids ≥ 6% was significantly associated with rhythmic risk (P = 0.015). For a threshold of 6%, the positive predictive value of the HCM Risk-Kids was only 27% and the negative predictive value of 95%. Among the 21 patients implanted with an ICD for primary prevention in whom the HCM Risk-Kids could be calculated: 4 had a score < 4% when the ICD was fitted, 7 had a score between 4 and 6% and 9 a score ≥ 6%. The only patient who used his ICD had a score of 9.4%. In DCM, apart from very specific etiologies (laminopathy, Barth, ischemic), the indication of ICD in primary prevention must be rigorously discussed on a case-by-case basis because there does not appear to be a rhythmic event in this population. Regarding the calculation of the HCM Risk Kids in the HCM population, it is not sufficient on its own to predict the risk of sudden death at 5 years in this population and should probably be coupled with the patient's genetic and MRI data to better stratify the rhythmic risk.