Abstract 3037: Sudden Death in 1803 Children With Dilated Cardiomyopathy: Rates and Risk Factors
BACKGROUND: Nonischemic dilated cardiomyopathy (DCM) is responsible for 10% of sudden cardiac deaths in adults. Clinical trials in adults have led to the Class 1 indication of automatic implantable cardiac defibrillators (AICDs) as therapy in adults with nonischemic DCM who have an LVEF ≤35% and who are in NYHA functional Class II or III for primary prevention of sudden cardiac death. The risk and incidence of sudden death in pediatric DCM is unknown.
METHODS: We used the Pediatric Cardiomyopathy Registry database to assess incidence and risk factors for sudden death in 1803 children with DCM diagnosed between 1990 –2/2009. A death was defined as sudden if it occurred <1 hour from onset of a cardiac event and was unexpected. Patient follow-up time was censored at heart transplantation (Htx).
RESULTS: Of 280 deaths identified, 35 were classified as sudden, 189 non-sudden, and 56 unknown. Competing risk analysis demonstrated the 1, 3, and 5-year cumulative rates for sudden death were 1.4%, 2.1%, and 2.5%; non-sudden death 8.4%, 9.9%, and 12.6%; and Htx 22%, 27%, and 30% (p< 0.001). The majority (74%) of sudden deaths occurred <2 years after presentation. Variables at time of diagnosis associated in univariate analysis with higher hazard of sudden death vs. all other patients were:
congestive heart failure (CHF) [hazard ratio (HR) 2.84, 95% confidence interval (CI) 1.1–7.4, p=.031];
use of anti-arrhythmic therapy [HR 3.1, 95% CI 1.1– 8.5, p=.032];
lowest tertile of the LV posterior wall thickness/LV end-diastolic dimension ratio (HR 2.7, 95% CI 1.2–5.9, p=.014]; and
moderate or greater tricuspid regurgitation (HR 4.5, 95% CI 1.1–18.9, p=.039).
Age, gender, ethnicity, DCM etiology, family history, and LV shortening fraction were not associated with an increased risk for sudden death.
CONCLUSIONS: Sudden death in pediatric DCM usually occurs within 2 years after diagnosis with a much lower frequency than occurs in adults with nonischemic DCM. Children with DCM who had either CHF at presentation or those who were taking antiarrhythmic medications at time of diagnosis are at higher risk for sudden death. These findings suggest that the use of AICDs in pediatric DCM should be limited to selected high risk children.