Risk Stratification In Long Qt Syndrome Patients With Very Prolonged Qtc Interval

Introduction: Long QT (LQT) syndrome patients with very prolonged QTc interval are at increased risk for worsened outcomes. We aimed to identify risk factors associated with adverse cardiac events in this group. Methods: We studied 673 patients from the Rochester, New York LQT syndrome registry with very prolonged QTc interval, defined as QTcu003e500 msec. Genotype data were available for 345 patients. Follow-up began after initial ECG and continued till age 50 years. Primary end point was any first cardiac event, consisting of syncope, aborted cardiac arrest, implantable cardioverter-defibrillator shock, and death. Secondary end point included only life-threatening cardiac events. Results: During mean follow-up of 11.0±8.1 years, crude rate of cardiac events was 32%. Clinical variables associated with primary end point were female gender agedu003e13 years compared to male gender agedu003e13 years (HR=1.89, 95% CI: 1.20-1.29, pu003c0.01) and prior syncope (HR=2.05, 95% CI: 1.49-2.82, pu003c0.001). Beta-blockers were signific...