Sudden Death in Childhood Cardiomyopathy | Journal Scan

Study Questions:

What are the incidence and risk factors for sudden cardiac death (SCD) in children with varying types of cardiomyopathy (CM)?

Methods:

This manuscript reports data from the National Australian Childhood Cardiomyopathy Study (NACCS), which is an ongoing longitudinal cohort study of all Australian children with primary CM. All children with CM <10 years of age, diagnosed between January 1, 1987 and December 31, 1996, were enrolled in the study. As implantable cardioverter-defibrillator (ICD) placement may have modified the risk of sudden death, a competing risk analysis was performed, with results presented as cumulative incidence of SCD, heart failure death/transplant, and ICD placement, along with the corresponding survival curve.

Results:

Of 289 eligible subjects, the CM phenotype was dilated (DCM) in 172 (59.5%), hypertrophic (HCM) in 80 (27.7%), left ventricular noncompaction (LVNC) in 29 (10%), and restrictive CM in 8 (2.8%). The majority of subjects were diagnosed during their first year of life (median age at diagnosis, 0.56 years; interquartile range [IQR], 0.15-1.91 years). Across the entire study population, 16 (5.5%) experienced SCD over a median follow-up of 11.9 (IQR, 1.7-15.4) years. The risk of SCD varied according to the underlying CM phenotype, and was 5% for DCM, 6% for HCM, 23% for LVNC, and 12% for restrictive CM. Risk factors for SCD in patients with DCM included older age at diagnosis, positive family history of CM, and severity of LV dysfunction. The only risk factor for SCD in HCM was a higher posterior wall thickness Z-score.

Conclusions:

Predictors of sudden death include CM phenotype, severity of LV dysfunction and family history in DCM, and extent of LV hypertrophy in HCM.

Perspective:

This manuscript reports results from an ongoing nationwide study in Australia of all pediatric patients with CM. The risk of sudden death was highest in patients with LVNC, which is higher than that reported in previous studies. Patients in this study were diagnosed at a relatively young age (median age, 0.56 years), which might be reflective of severity of disease, and impact the risk for sudden death. Additionally, the number of patients with LVNC and restrictive CM was relatively small, limiting the analysis and interpretation of data from these groups. The goal of future studies will be to continue to hone in on the population of patients who would benefit most from primary prevention ICDs.

Clinical Topics: Arrhythmias and Clinical EP, Congenital Heart Disease and Pediatric Cardiology, Heart Failure and Cardiomyopathies, Prevention, Implantable Devices, SCD/Ventricular Arrhythmias, Congenital Heart Disease, CHD & Pediatrics and Arrhythmias, CHD & Pediatrics and Quality Improvement, Acute Heart Failure

Keywords: Cardiomyopathy, Dilated, Cardiomyopathy, Hypertrophic, Cardiomyopathy, Restrictive, Cardiomyopathies, Child, Cohort Studies, Death, Sudden, Death, Sudden, Cardiac, Defibrillators, Implantable, Follow-Up Studies, Heart Defects, Congenital, Heart Failure, Hypertrophy, Left Ventricular, Incidence, Longitudinal Studies, Phenotype, Primary Prevention, Risk Factors


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