Abstract 1158: Sudden Death in Children with Cardiomyopathy: Long Term Follow-Up from a National Population-Based Study of Childhood Cardiomyopathy

Abstract

Introduction Better data regarding the incidence and risk factors for sudden cardiac death (SCD) in children with cardiomyopathy (CM) is critical in defining appropriate primary prevention strategies. Methods The National Australian Childhood Cardiomyopathy Study is a prospective cohort study, including all children in Australia with primary CM diagnosed at 0 – 10 years of age, between 1987–1997. SCD was defined as sudden and unexpected death in children who were not hospitalized and not in congestive heart failure at the time of death. Nine subjects with sudden death as presenting symptom were excluded. Indexed echocardiographic measurements at latest follow-up were compared between subjects with SCD and survivors. Results Study criteria were met by 291 children. Mean duration of follow-up was 9.2 years. The incidence of sudden death relative to each CM type, for all cases and as a proportion of deaths, is shown in the Table : Incidence of SCD by CM type. SCD incidence was significantly associated with CM type, for all cases ( p = 0.006) and when only those subjects who died were considered ( p = 0.005), with LVNC and RCM having up to 4 times the risk of other CM types. Children with familial DCM had a significantly higher rate of SCD than subjects with non-familial CM (12% vs 3%; p = 0.028), however, familial CM was not a risk factor in other CM types. DCM SCD subjects had larger LVEDd Z score than survivors (median 5.53 vs 1.16; p <0.0001) and lower FS Z score (median −9.23 vs −0.51; p = 0.0025). HCM SCD subjects had thicker LVPW dimension Z scores than survivors (median 4.63 vs 1.18; p = 0.007). Twelve subjects (2 DCM, 8 HCM and 2 LVNC) underwent ICD implantation (8/12 for primary prevention). Conclusions: This population based study defines new risk factors for sudden death in children with CM. RCM is well known to have a high incidence of SCD. In addition, children with LVNC and those with DCM who have severe dilatation, systolic dysfunction or familial DCM are at increased risk of sudden death.