Electronic cigarettes prolong ventricular repolarization in people who smoke tobacco cigarettes: implications for harm reduction

Abstract

Electronic cigarettes are often used for smoking cessation as a harm reduction strategy, but studies comparing risks of electronic cigarettes (ECs) and tobacco cigarettes (TCs) are scarce. Ventricular repolarization in people who smoke TCs is abnormal. Baseline repolarization was compared among non-smokers, and people who use ECs or TCs. Then, the acute effects of ECs and TCs on metrics of ventricular repolarization, were compared in people who chronically smoke. A total of 110 participants(59 female), including 35 people(21 females) in the TC cohort, 34 people(17 females) in the EC cohort, and 41 people(21 females) in the Non-Smoker (NS) cohort were included. None of the primary outcomes, Tp-e, Tp-e/QT, and Tp-e/QTc, was different among the three cohorts at baseline, even when adjusted for sex. Compared to the control exposure, standing after acutely using the EC, but not the TC significantly prolonged all three primary indices of ventricular repolarization in people who smoke TCs. The major new finding in this study is that in people who smoke TCs, using an EC compared to a TC significantly prolongs ventricular repolarization. Further, in our subgroup analysis by sex, this adverse effect on repolarization is found only in male, not female smokers. In summary, chronic TC smoking is the most prevalent, modifiable risk factor for cardiovascular death, including sudden cardiac death. If used for smoking cessation, ECs should only be used in the short term since they too carry their own risks; this risk appears to be greatest in males compared with females who smoke.

Arrhythmogenic effects of acute electronic cigarette compared to tobacco cigarette smoking in people living with HIV

“…In our prior retrospective study, we reported a greater Tp‐e prolongation following acute TC smoking compared to EC use in the general population who smoke (Ip et al., 2020 ). In a prospective study comparing the acute effect of TCs and ECs on VR in the same individual, we found that ECs but not TCs significantly increased the Tp‐e interval following a provoked acute increase in heart rate (Ruedisueli et al., 2023 ). These findings are supported by preclinical studies in which acute exposure to aerosols generated from heating vegetable glycerin (VG) and/or propylene glycol (PG), both common EC liquid constituents, significantly prolonged ventricular repolarization in mice (Carll et al., 2022 ).…”

“…Several important points are worth emphasizing: First, although the increase in plasma nicotine was smaller following acute EC use compared to TC smoking, the increase was nonetheless significant. Second, the difference in nicotine levels occurred in PLWH despite using the same protocol we have used in many studies for many years, which, in the general adult population, reliably and consistently produced similar plasma nicotine levels as smoking one TC (Arastoo et al., 2020 ; Haptonstall et al., 2020 ; Nguyen et al., 2024 ; Ruedisueli et al., 2023 ). Potential explanations the difference in the current study include a possible interaction of HIV drugs or the HIV milieu that impacted metabolism of nicotine delivered by the EC device differently from the TC.…”

“…Since our primary outcomes were related to the change in nicotine pre/post exposure, not the absolute final nicotine level, this smoking proximate to the study assumes less importance. Finally in the current study, we did not include a provocative maneuver to unmask any differences in VR as we did in our prior study comparing acute effects of TCs and ECs on VR in the general population (Ruedisueli et al., 2023 ). Future studies should include such a protocol.…”