Exposure to electronic-cigarette aerosols cause irregular heartbeats in mice, University of Louisville researchers report

 Mathew Nystoriak, associate professor of medicine,
watches assistant professor Alex Carll. (UofL photo)

By Melissa Patrick
Kentucky Health News

Exposure to electronic-cigarette aerosols can cause heart arrhythmias in mice — in both premature and skipped beats, according to a University of Louisville study. 

Published in the peer-reviewed scientific journal Nature Communications, the study suggests that exposure to specific chemicals in e-cigarette liquids promote irregular heartbeats and cardiac electrical dysfunction, which could increase the risk for atrial or ventricular fibrillation and heart attacks. 

“Our team’s findings that specific ingredients in e-cigarette liquids promote arrhythmias indicates there is an urgent need for more research into the cardiac effects of these components in both animals and humans,” lead researcher Alex Carll, an assistant professor in the UofL Department of Physiology, said in a news release.

The researchers looked at the cardiac effects of inhaled aerosols generated from e-cigarette liquids with and without nicotine . 

"For all e-cigarette aerosols, the animals’ heart rate slowed during puff exposures and sped up afterwards as heart rate variability declined, indicating fight-or-flight stress responses," they write. "In addition, e-cigarette puffs from a menthol-flavored e-liquid or from propylene glycol alone caused ventricular arrhythmias and other conduction irregularities in the heart." 

The study was conducted in collaboration with Daniel Conklin and Aruni Bhatnagar, professors in the UofL Division of Environmental Medicine. 

"The findings are important because they provide fresh evidence that the use of e-cigarettes could interfere with normal heart rhythms — something we did not know before," Bhatnagar said in the release. "This is highly concerning given the rapid growth of e-cigarette use, particularly among young people."

The release said the research adds to a growing body of knowledge on the potential toxicity and health impacts of e-cigarettes reported by the American Heart Association Tobacco Regulation and Addiction Center, for which UofL serves as the flagship institute.

This research contributes to the ongoing debate of whether e-cigarettes are safer to use than combustible products.

For example, the release notes that while vaping does not involve combustion, thus exposing users and bystanders to little if any carbon monoxide, tar or cancer-causing nitrosamines like traditional cigarettes, e-cigarettes can deliver aldehydes, particles and nicotine at levels comparable to combustible cigarettes. 

Proponents of e-cigarettes contend that vaping helps smokers quit smoking traditional cigarettes, but the appeal of the products and their addictiveness have led to increases in youth vaping, even as the long-term risks of the products have not yet been determined.