Background and objectives: Congenital long QT syndrome (LQTS) predisposes affected individuals to ventricular tachycardia/fibrillation (VF/VF), potentially resulting in sudden cardiac death. The Tpeak-Tend interval and the Tpeak-Tend/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 Tpeak-Tend intervals and Tpeak-Tend/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. Tpeak-Tend intervals were longer (mean difference [MD]: 13ms, standard error [SE]: 4ms, P=0.002; I2=34%) in congenital LQTS patients with adverse events [syncope, ventricular arrhythmias or sudden cardiac death] compared to LQTS patients without such events. By contrast, Tpeak-Tend/QT ratios were not significantly different between the two groups (MD: 0.02, SE: 0.02, P=0.26; I2=0%).
Conclusion: This meta-analysis showed that Tpeak-Tend interval is significant higher in individuals who are at elevated risk of adverse events in congenital LQTS, offering incremental value for risk stratification.
Keywords: Dispersion of repolarization; Risk stratification; Sudden cardiac death; Tpeak–Tend; Tpeak–Tend/QT; Ventricular arrhythmia.
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