QT interval prolongation and risk for cardiac events in genotyped LQTS-index children.

Wedekind H, Burde D, Zumhagen S, Debus V, Burkhardtsmaier G, Mönnig G, Breithardt G, Schulze-Bahr E

Abstract

Congenital long-QT syndrome (LQTS) is an inherited cardiac disorder with a disturbance in repolarization characterized by a prolonged QT interval on the surface electrocardiogram and life-threatening ventricular tachycardia. Publications from the International LQTS Registry have provided information that the cardiac risk may be influenced by gender, genotype, exposure to arrhythmia triggers, and previous cardiac events. In children, early-onset of disease, changes in life style, and medical treatment is a sensitive issue and significant, gender-related differences of a first life-threatening event were reported. Thus, we investigated the clinical features of a large genotyped population of LQTS-index children (age 500 ms was a strong and significant predictor for cardiac events during follow-up (p = 0.02). Furthermore, a prior syncope [hazard ratio (HR), 4.05; 95% confidence interval (CI), 1.1 to 15.0; p = 0.03] or an ACA (HR, 11.7; 95% CI, 3.1 to 43.4; p = <0.001) identified children with an increased risk for recurrent cardiac events compared to asymptomatic LQT children. LQTS-index children manifest with a high percentage of severe symptoms. Among presently validated risk factors for LQTS, a QTc interval >500 ms and a history of prior syncope or ACA were strong predictors for recurrent cardiac events.