Effect of smoking on Tp-e interval, Tp-e/QT and Tp-e/QTc ratios as indices of ventricular arrhythmogenesis.

BACKGROUND: Smoking may lead to ventricular arrhythmias and sudden cardiac death via altering ventricular recovery time dispersion indices such as QT interval and QT dispersion (QTd). The Tp-e/QT and Tp-e/QTc ratios are also known as predictors of ventricular arrhythmogenesis. The aim of this study was to evaluate the relationship between cigarette smoking and ventricular repolarisation dispersion using these novel electrocardiographic parameters.

METHODS: One hundred and twenty-one chronic smokers and 70 age- and sex-matched non-smoker controls were included in our study. The Tp-e interval and Tp-e/QT ratio were measured by 12-lead electrocardiogram, and corrected for heart rate.

RESULTS: QTd (34.2 ± 8.4, 27.2 ± 10.4, P<0.001) and corrected QTd (37.3 ± 8.9, 29.8 ± 11.2, P<0.001) were significantly increased in the smokers compared to the non-smoker control group. The Tp-e interval (76.5 ± 6.3, 70.3 ± 6.8, P<0.001), cTp-e interval (83.5 ± 8.0, 77.1 ± 8.7, P<0.001), Tp-e/QT (0.20 ± 0.03, 0.19 ± 0.02, P<0.001) and Tp-e/QTc ratios (0.19 ± 0.02, 0.17 ± 0.02, P<0.001) were increased in the patient group when compared to the controls. Significant positive correlations were also found between the level of smoking with the cTp-e interval (r=0.836, P<0.001), and Tp-e/QT (r=0.714, P<0.001) and Tp-e/QTc ratios (r=0.448, P<0.001).

CONCLUSION: We found in our study that cTp-e interval, Tp-e/QT and Tp-e/QTc ratios were increased in smokers and significantly correlated to the amount of smoking.