Time-dependent Risk Prediction Score of Life-threatening Cardiac Events in Patients With Long QT Syndrome

Introduction: Currently there is no integrated risk stratification algorithm to predict life-threatening cardiac events in ICD treatment-naive long QT syndrome (LQTS) patients. We aim to develop a risk prediction score to predict life-threatening cardiac events in LQTS patients that accounts for changes in risk factors over time. Methods: Using Time-dependent Cox models, we developed a risk prediction score for a composite endpoint of aborted cardiac arrest or sudden cardiac death (ACA/SCD) in 1680 LQTS patients who were genotype-positive for LQT1, LQT2, or LQT3. The model included time-dependent covariates of history of syncope (never, syncope while off beta blockers, and syncope while on beta blockers), use of beta blockers, the interaction terms of these two variables, and gender by age before and after 14 years, as well as time-fixed baseline QTc and genotype. Follow-up started from birth and was censored at the age of 50 years, time of ICD implantation, or last contact, whichever occurred first. The ...