Randomized crossover trial comparing short-term hemodynamic and autonomic effects of e-cigarettes with and without nicotine and conventional cigarette smoking in apparently healthy individuals.

Aims: To assess the short-term cardiovascular and autonomic nervous system effects of electronic nicotine delivery systems (ENDS), electronic non-nicotine delivery systems (ENNDS), and conventional cigarettes in apparently healthy adults. Methods: In this randomized crossover study, 42 healthy volunteers aged 18-60 years with a history of conventional cigarette smoking completed three experimental sessions in random order, using ENDS, ENNDS, or conventional cigarettes. Hemodynamic and autonomic parameters-including heart rate (HR), systolic, diastolic, and mean blood pressure (SBP, DBP, MBP), stroke volume (SV), total peripheral resistance (TPR), and heart rate variability (HRV)-were continuously recorded on a beat-to-beat basis using a Task Force Monitor. Results: ENDS use induced acute changes: HR increased by 7.2 bpm (during intervention), SBP by 3.4 mmHg, DBP by 3.3 mmHg, and MBP by 3.7 mmHg. SV decreased, and HRV analysis indicated a shift towards sympathetic dominance. Conventional cigarettes caused similar, but more pronounced increases in SBP, DBP, and MBP during intervention (e.g., SBP 2.9 mmHg higher than ENDS). ENNDS resulted in smaller increases in HR (5.6 bpm less than ENDS), SBP (2.7 mmHg less), DBP (2.1 mmHg less), and MBP (2.6 mmHg less) compared to ENDS. Conclusion: ENDS and conventional cigarettes both induce acute cardiovascular stress, characterized by increased HR and BP, reduced SV, and sympathetic activation. The hemodynamic and autonomic effects of ENDS closely resemble those of conventional cigarettes. Although attenuated, ENNDS use was not physiologically neutral, raising concerns regarding its cardiovascular safety as an alternative to traditional smoking. Public trial registration: ClinicalTrials.gov, NCT03037775.