Abstract 13745: Nicotine Delivered by Electronic Cigarette Vapor or Standard Cigarettes Adversely Affects Left Ventricular Systolic Function Measured by Cardiovascular Intrinsic Frequency in Rats

Abstract

Introduction: Cardiovascular intrinsic frequency (IF) is a systems approach for the analysis of left ventricle (LV) function, arterial dynamics, and LV-arterial coupling. It was shown in a recent Framingham Heart Study (Hypertension 2021, 77(2):338-346) that higher values of the first IF (ω 1 ) (derived from carotid pressure waveforms) are associated with higher risk for incident heart failure and composite CVD events. Here, we examined the effect of chronic exposure to E-cigarette and standard cigarette on ω 1 in rats. Methods: Adult male and female Sprague Dawley rats were exposed to: 1) Purified air ( n =6); 2) E-cigarette vapor without nicotine ( n =6); 3) E-cigarette vapor plus nicotine (similar amount of nicotine as the standard cigarette, n =6); and 4) Standard nicotine-containing cigarette smoke ( n =9). E-cigarette was a 3rd generation type E-cigarette from VaporFi, tank model: Volt 2. Rats were placed into a nose-only exposure system. The exposures took place for 5 hours/day, 4 days/week for a total of 8 weeks. The E-liquid was a 50/50 propylene glycol/glycerin mixture with a tobacco flavor additive. After 8 weeks of exposure, the rats were anesthetized to measure the hemodynamics including invasive carotid pressure waveforms. IF parameters were computed from pressure waveforms with similar cardiac cycles. Results: There was no difference in ω 1 between purified air and E-cigarette vapor without nicotine; there was no significant difference in ω 1 between E-cigarette vapor with nicotine versus standard nicotine-containing cigarette smoke. ω 1 was significantly higher (P<0.005) in the nicotine-containing groups versus the non-nicotine containing groups (Fig.1). Conclusions: Our results suggest that nicotine delivered either by standard cigarette smoke or E-cigarette vapor adversely affects the LV systolic function, and ω 1 measured from the carotid waveform alone (that can be measured non-invasively with an iPhone app), can capture these negative effects.