Abstract 15665: Pod-Based Electronic Cigarette Use Alters Measures of Heart Rate Variability

Abstract

Background: Previous studies demonstrate changes in autonomic function with combustible and earlier generation electronic cigarette (ecig) use. We sought to explore the effects of nicotine salt containing pod-based ecigs on autonomic regulation in young adult regular users by analyzing indices of heart rate variability (HRV). Methods: We enrolled healthy adults (18-45 yo) who were self-reported tobacco nonusers, pod-based ecig users, or combustible cigarette users. Participants were asked to refrain from tobacco product use at least 6 h before the study visit. Indices of HRV: standard deviation of the NN intervals (SDNN) and the root mean square differences of successive NN intervals (RMSSD, measure of parasympathetic function) were measured by Sphygmacor before and 10 minutes after structured use of participants’ own product. Measurements of urinary levels of cotinine, a nicotine metabolite, and 3HPMA, an acrolein metabolite, were made 1 h after product use. Results: In 133 subjects (age 26±5, 49% women), baseline HRV measures were comparable among tobacco non-users (N=39), pod-based ecig users (N=64), and combustible cigarette users (N=30). Analyses adjusted for age and sex demonstrated that acute pod-based ecig use reduced SDNN compared with non-use (-5.9±2.6ms vs 6.5±3.2ms, P=0.004) and similar to the effect of combustible cigarette use (-10.2±3.8ms, P=0.37). Moreover, acute pod-based ecig use reduced RMSSD compared with non-use (-5.6±3.3ms vs 5.4±4.1ms, P=0.04) and similar to the effect of combustible cigarette use (-10.9±4.9ms, P=0.38). Urinary cotinine, reflective of nicotine exposure, was associated with decreases in SDNN and RMSSD (r=-0.33, P=0.001; r=-0.29,P=0.003, respectively) whereas 3HPMA associated with SDNN and showed a trend toward association with RMSSD (r=-0.27, P=0.006; r=-0.18, P=0.06, respectively). Conclusion: Our data demonstrate an association between acute use of pod-based ecigs and altered cardiac autonomic function in association with the level of nicotine and acrolein exposure.