Abstract 13764: Chronic Electronic Cigarette Vapor Exposure Leads to Impaired Cardiac Function in Experimental Rat Myocardial Ischemia/reperfusion Model

Abstract

Background: We investigated the effects of long-term electronic cigarettes with nicotine (eC) vaping on cardiac function and structure in rats subjected to myocardial infarction (MI). Methods: After 8 weeks of exposure to either pure air (n=20) or eC (n=20), rats were anesthetized, and were subjected to 30 minutes of coronary artery occlusion followed by 3 hours of reperfusion. Cardiac function was assessed by echocardiogram and pressure measurements of the aorta and left ventricle (LV). Cardiac output (CO) was measured using a thermodilution catheter. At 3 hours of reperfusion, ischemic risk zone, no-reflow and infarct areas were determined. Results: Prior to coronary artery occlusion, chronic eC exposure was associated with a lower CO (45 ± 2 ml/min ) compared to air (55 ± 4 ml/min; p<0.05)) and a decrease in +dP/dt (5226 ± 294 mmHg/s versus 6062 ± 271 mmHg/s; p=0.05). After 30 minutes of coronary occlusion and 2.5 hours of reperfusion, CO and LV + dp/dt fell in both groups, but remained significantly lower in eC compared to the pure air group (Table). LV systolic and diastolic dimensions were significantly smaller in the E-Cig group compared to the air group. Systolic and diastolic anterior LV wall thickness were significantly thicker in the eC group after reperfusion. The ischemic risk size was comparable between the 2 groups. MI size was 48.8 ± 4.8% of the ischemic risk zone in the air group and 45.4 ± 4.4 % in the eC group (p=0.603). The area of no reflow was 26.7 ± 4.0% of the ischemic risk zone in the air group and 21.1 ± 3.5% in the E-C group (p=0.298). Chronic eC exposure did not change heart rate and blood pressure, but the significantly increased the systemic arterial resistance. Conclusions: Chronic exposure to eC significantly impaired cardiac function in rats prior to and during ischemia/reperfusion, increased arterial resistance, but did not increase infarct size or no-reflow zone. Increased LV wall thickness of the risk zone suggested that eC may have increased edema.