Sex differences on the electrocardiographic pattern of cardiac repolarization: Possible role of testosterone

Background Cardiac repolarization has been shown to be shorter and faster i n men compared with women. In this study, we examined the electrocardiograp hic pattern of repolarization in patients with abnormal plasma levels of te stosterone to gain insight into the role that this hormone plays in modulat ing repolarization. Methods and Results Repolarization was measured in 27 castrated men, 26 wom en with virilization, and 53 control subjects pair-matched for age and sex. Repolarization in castrated men was slower and longer than that of normal men. Women with virilization exhibited a shorter and faster repolarization than normal women and castrated men. These differences are the opposite of those found in the normal population. Finally, the changes observed in cast rated men may be reverted by testosterone. Conclusions We conclude that testosterone plays an important role in modula ting cardiac repolarization.