Ventricular premature beats (VPBs) were commonly seen in the population. However, the clinical presentation and prognosis of VPBs varied from a total lack of symptoms to fatal arrhythmias. Therefore, identifying dangerous VPBs (malignant VPBs) has always been a topic and challenge in clinical research. Accumulative data have shown that the risk level of VPBs was associated with structural heart disease (SHD) such as ischemic heart disease [1,2].

Repolarization abnormalities such as prolonged QT interval, increased QT dispersion, T-wave alternans (TWA) and microvolt TWA were recognized as risk markers for cardiovascular mortality and sudden cardiac death [[3], [4], [5], [6], [7], [8], [9]]. Since postextrasystolic repolarization changes of VPBs were first reported by P.D.White in 1915 [10], a lot of studies have been attempted to reveal its clinical value [[11], [12], [13], [14]]. At present, it is believed that changes in the U wave after VPBs are associated with the occurrence of malignant arrhythmia [13,14], while changes in the T wave are only found to be a warning sign in some special patients such as Long QT Syndrome(LQTS) [15,16]. However, the prognostic significance of postextrasystolic repolarization changes of VPBs in patients without LQTS is less clear. Hence, in this study, postextrasystolic repolarization changes were evaluated for their association with SHD and possible prognostic value was assessed in patients without LQTS.