Purpose: We investigated the effects of exposure to electronic cigarettes (E-cig) vapor on the sizes of the no-reflow and myocardial infarction regions, and cardiovascular function compared to exposure to purified air and standard cigarette smoke.
Methods and results: Sprague Dawley rats (both male and female, 6 weeks old) were successfully exposed to filtered air (n = 32), E-cig with nicotine (E-cig Nic+, n = 26), E-cig without nicotine (E-cig Nic-, n = 26), or standard cigarette smoke (1R6F reference, n = 31). All rats were exposed to inhalation exposure for 8 weeks, prior to being subjected to 30 minutes of left coronary artery occlusion followed by 3 hours of reperfusion. Exposure to E-cig vapor with or without nicotine or exposure to standard cigarettes did not increase myocardial infarct size or worsen the no-reflow phenomenon. Exposure to E-cig Nic+ reduced the body weight gain, and increased the LV weight normalized to body weight and LV wall thickness and enhanced the collagen deposition within the LV wall. E-cig exposure led to cardiovascular dysfunction, such as reductions in cardiac output, LV positive and negative dp/dt, suggesting a reduction in contractility and relaxation, and increased systemic arterial resistance after coronary artery occlusion and reperfusion in rats compared to air or cigarette exposure.
Conclusions: E-cig exposure did not increase myocardial infarct size or worsen the no-reflow phenomenon, but induced deleterious changes in LV structure leading to cardiovascular dysfunction and increased systemic arterial resistance after coronary artery occlusion followed by reperfusion.
Keywords: electronic-cigarettes; myocardial infarction; no-reflow phenomenon; standard cigarette smoking.