Meta-analysis of T _peak –T _end and T _peak –T _end /QT ratio for risk stratification in congenital long QT syndrome

Background and objectives: Congenital long QT syndrome (LQTS) predisposes affected individuals to ventricular tachycardia/fibrillation (VF/VF), potentially resulting in sudden cardiac death. The T _peak –T _end interval and the T _peak –T _end /QT ratio, electrocardiographic markers of dispersion of ventricular repolarization, were proposed for risk stratification but their predictive values in LQTS have been controversial. A systematic review and meta-analysis was conducted to examine the value of T _peak –T _end intervals and T _peak –T _end /QT ratios in predicting arrhythmic and mortality outcomes in congenital LQTS. Method: PubMed and Embase databases were searched until 9th May 2017, identifying 199 studies. Results: Five studies on long QT syndrome were included in the final meta-analysis. T _peak –T _end intervals were longer (mean difference [MD]: 13 ms, standard error [SE]: 4 ms, P = 0.002; I ² = 34%) in congenital LQTS patients with adverse events [syncope, ventricular arrhythmias or sudden cardiac death] compared to LQTS patients without such events. By contrast, T _peak –T _end /QT ratios were not significantly different between the two groups (MD: 0.02, SE: 0.02, P = 0.26; I ² = 0%). Conclusion: This meta-analysis showed that T _peak –T _end interval is significant higher in individuals who are at elevated risk of adverse events in congenital LQTS, offering incremental value for risk stratification.