Abstract 2794: Electrocardiographic Predictors of Sudden Cardiac Death in Pediatric Hypertrophic Cardiomyopathy
Introduction: Hypertrophic cardiomyopathy (HCM) is a common cause of sudden cardiac death in young athletes. The abnormalities on electrocardiogram (ECG) seen in HCM during childhood that relate to sudden cardiac death have not been well classified. The purpose of this study was to define the ECG findings in a known population of children with HCM and their relation to the occurrence of sudden cardiac death.
Hypothesis: We examined the hypothesis that the ECG is useful in predicting sudden cardiac death in children with hypertrophic cardiomyopathy.
Methods: All patients (pts) with HCM diagnosed by echocardiography followed at our center were retrospectively identified. Electrocardiographic data, including QRS voltages, character of q waves, presence of atrial enlargement, and conduction or repolarization abnormalities were assessed on the first available ECG at diagnosis. Pts with coexisting structural heart defects, an identified genetic syndrome, or diagnosed at <2 years of age were excluded. Clinical data were reviewed to establish a history of sudden cardiac death.
Results: Complete data sets were available for 102 children, average age at diagnosis 11.7 ± 3.8 years. The ECG was normal in 19% and abnormal in 81% of pts. The most common abnormalities were ventricular hypertrophy (57%), and T wave inversions or ST segment depression of >1mm in the inferior and/or lateral leads (51%). Eleven pts (11%) had a sudden cardiac death event. Among these pts with an event, two ECG findings were significant in comparison to pts without a sudden cardiac death event - right and/or left atrial enlargement (p=0.004), and ST segment depression and T wave inversions (p=0.02), specifically in the lateral leads (p =0.01). One patient who suffered a sudden cardiac death had a normal ECG.
Conclusions: The ECG findings in pediatric patients with HCM vary greatly. The most common abnormal findings are ventricular hypertrophy, T wave inversions, and ST segment changes. A normal ECG does not exclude the risk of sudden cardiac death. Atrial enlargement and significant ST segment and T wave changes, particularly in the lateral leads, occur with a higher frequency in pts with a sudden cardiac death event, and may be a marker to identify children with HCM at a higher risk of sudden cardiac death.