Novel conduction-repolarization indices for the stratification of arrhythmic risk.

Abstract

Sudden cardiac death (SCD) affects approximately 800,000 individuals per annum globally.[1] It is most frequently due to cardiac tachy-arrhythmias, which include mono-morphic or polymorphic ventricular tachycardia (VT), torsade de pointes and ventricular fibrillation (VF). Risk stratification for SCD remains a challenging problem in clinical practice. Patients with structural heart disease or cardiac ion channelopathies have an increased risk of SCD, their risks are not the same. Consequently, several indices have been devised for this purpose, mainly focusing on ventricular repolarization, which is reflected by the QT interval on the electrocardiogram.[2] These include QT interval corrected for heart rate (QTc), QT dispersion (QTd), interval from the peak to the end of the T wave (Tpeak – Tend, reflecting increased transmural dispersion of repolarization, TDR), and (Tpeak – Tend)/QT ratio.[3]