Tobacco and Electronic Cigarettes Adversely Impact ECG Indices of Ventricular Repolarization: Implication for Sudden Death Risk
https://journals.physiology.org/doi/abs/10.1152/ajpheart.00738.2019
Abstract
Tobacco cigarette(TC) smoking is associated with increased sudden death risk, perhaps through adverse effects on ventricular repolarization(VP). The effect of electronic-cigarettes(ECs) on VP is unknown. Objective To test the hypothesis that TCs and ECs have similar adverse effects on electrocardiogram(ECG) indices of VP, and these effects are attributable to nicotine. Methods ECG recordings were obtained in 37 TC-smokers, 43 EC-users, and 65 non-users. Primary outcomes, Tpeak-to-Tend(Tp-e), Tp-e/QT, and Tp-e/QTc, were measured in TC-smokers pre/post straw-control and smoking one TC, and in EC-users and non-users pre/post straw control and using an EC with and without nicotine(different days). Results Mean values of the primary outcomes were not different among the 3 groups at baseline. In TC-smokers, all primary outcomes including the Tp-e(12.9±5.0%vs1.5±5%, p=0.017), Tp-e/QT (14.9±5.0%vs0.7±5.1%, p=0.004), and Tp-e/QTc(11.9±5.0%vs2.1±5.1%, p=0.036), were significantly increased pre/post smoking one TC compared to pre/post straw-control. In EC-users, the Tp-e/QT(6.3±1.9%, p=0.046) was increased only pre/post using an EC-with-nicotine, but not pre/post the other exposures. The changes relative to the changes after straw-control were greater after smoking the TC compared to using the EC with nicotine for Tp-e(11.4±4.4%vs1.1±2.5%, p<0.05) and Tp-e/QTc(9.8±4.4%vs-1.6±2.6%, p=0.05), but not Tp-e/QT(14.2 ± 4.5%vs4.2±2.6%, p=0.06) . Heart rate increased similarly after the TC and EC-with-nicotine. Conclusions Baseline ECG-indices of VP were not different among TC-smokers, EC-users and non-users. An adverse effect of acute TC smoking on ECG indices of VP was confirmed. In EC-users, an adverse effect of using an EC-with-nicotine, but not without nicotine, on ECG indices of VP was also observed.