Risk Factors for Aborted Cardiac Arrest and Sudden Cardiac Death in Children With the Congenital Long-QT Syndrome

The congenital long-QT syndrome (LQTS) is an important cause of sudden cardiac death in children without structural heart disease. However, specific risk factors for life-threatening cardiac events in children with this genetic disorder have not been identified. Cox proportional-hazards regression modeling was used to identify risk factors for aborted cardiac arrest or sudden cardiac death in 3015 LQTS children from the International LQTS Registry who were followed up from 1 through 12 years of age. The cumulative probability of the combined end point was significantly higher in boys (5%) than in girls (1%; P 500 ms (hazard ratio [HR]; 2.72; 95% confidence interval [CI], 1.50 to 4.92; P=0.001) and prior syncope (recent syncope [< 2 years]: HR, 6.16; 95% CI 3.41 to 11.15; P or = 2 years]: HR, 2.67; 95% CI, 1.22 to 5.85; P=0.01) in boys, whereas prior syncope was the only significant risk factor among girls (recent syncope: HR, 27.82; 95% CI, 9.72 to 79.60; P