The effects of cigarette smoking on the heterogeneity of ventricular repolarization

Background Although the circulatory effects of cigarette smoking have been studied extensively, its impact on ventricular repolarization has not been adequately evaluated. Methods The goal of our study was to determine whether cigarette smoking in fluences the spatial and temporal heterogeneity of ventricular repolarizati on in a population of young, healthy, male subjects. A digital 12-lead surf ace electrocardiogram was obtained from 1394 men recruited from the Helleni c Air Force and classified as smokers and nonsmokers. The maximum, minimum, and median QT intervals, QT dispersion (QT maximum - QT minimum), the rate -corrected maximum and median QT intervals, the slopes of the QT maximum/RR and QT median/RR regression equations, and the vectorcardiographic markers spatial T amplitude and spatial QRS-T angle were evaluated in the 2 groups . Results Heart rate was significantly higher (P < .001) in smokers (n = 691) compared with nonsmokers (n = 703). QT maximum, QT minimum, and QT median were significantly lower (P < .001), whereas the rate-corrected QT maximum (P = .04) and QT median (P = .06) were marginally higher in smokers than in nonsmokers. The spatial T amplitude was lower (P = .002), whereas the spat ial QRS-T angle was higher (P = .01) in smokers compared with nonsmokers. N either QT dispersion nor the slopes of the QT/RR and the spatial descriptor s/RR regression equations differed between smokers and nonsmokers. Conclusions Ventricular repolarization is altered in young male cigarette s mokers. The differences in the heterogeneity of ventricular repolarization between smokers and nonsmokers are mainly due to heart rate differences bet ween the 2 study groups.