Abstract
Background: Acquired QT interval prolongation has been linked with malignant ventricular arrhythmias, such as torsade de pointes, in turn predisposing to sudden cardiac death. Increased dispersion of repolarization has been identified as a pro-arrhythmic factor and can be observed as longer T(peak) - T(end) interval and higher T(peak) - T(end)/QT ratio on the electrocardiogram. However, the values of these repolarization indices for predicting adverse outcomes in this context have not been systematically evaluated. Method: PubMed, Embase and Cochrane Library databases were searched until 14th February 2018, identifying 232 studies. Results: Five studies on acquired QT prolongation met the inclusion criteria and 308 subjects with drug-induced LQTS patients (mean age: 66 ± 18 years old; 46% male) were included in this meta-analysis. T(peak) - T(end) intervals were longer [mean difference [MD]: 76 ms, standard error [SE]: 26 ms, P = 0.003; I(2) = 98%] and T(peak) - T(end)/QT ratios were higher (MD: 0.14, SE: 0.03, P = 0.000; I(2) = 29%) in patients with torsade de pointes compared to those without these events. Conclusion: T(peak) - T(end) interval and T(peak) - T(end)/QT ratio were higher in patients with acquired QT prolongation suffering from torsade de pointes compared to those who did not. These repolarization indices may provide additional predictive value for identifying high-risk individuals.