E-cigarettes may disrupt heart rhythm, hike risk of sudden cardiac arrest

University of Louisville professors Alex Carll (front) and Matthew Nystoriak are exploring the effects of e-cigarettes and vaping on the heart. Photo courtesy of the University of Louisville
University of Louisville professors Alex Carll (front) and Matthew Nystoriak are exploring the effects of e-cigarettes and vaping on the heart. Photo courtesy of the University of Louisville

Oct. 25 (UPI) -- Exposure to specific chemicals within e-cigarette liquids may trigger heart arrhythmias and electrical dysfunction -- cardiac effects similar to or worse than what conventional cigarettes may cause, a new study suggests.

The research from University of Louisville's Christina Lee Brown Envirome Institute found that exposure to e-cigarette aerosols can cause heart arrhythmias -- premature and skipped heart beats -- in mice models.


The findings were published Tuesday in Nature Communications.

"Our findings demonstrate that short-term exposure to e-cigarettes can destabilize heart rhythm through specific chemicals within e-liquids," Alex Carll, assistant professor in the University of Louisville's Department of Physiology,said in a news release.

According to Carll, who led the study, this suggests that e-cigarette use "involving certain flavors or solvent vehicles" may disrupt the heart's electrical conduction and provoke arrhythmias, which could increase the risk for atrial or ventricular fibrillation and sudden cardiac arrest.

Given that specific ingredients in e-cigarette liquids were shown to promote arrhythmias underscores the "urgent need" for more research into the cardiac effects of these components in animals and humans, Carll said.

"The findings of this study 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," Aruni Bhatnagar, professor in the University of Louisville's Division of Environmental Medicine, said in the release.


Bhatnagar added: "This is highly concerning given the rapid growth of e-cigarette use, particularly among young people."

In 2021, about 2.8% of middle school students, and 11.3% of high school students, reported that they had used electronic cigarettes in the past 30 days, according to the Centers for Disease Control and Prevention.

The CDC says e-cigarettes have been the most commonly used tobacco product among youth since 2014.

For the study, the scientists tested the heart effects on mice from inhaled e-cigarette aerosols from the two main ingredients in e-liquids -- nicotine-free propylene glycol and vegetable glycerin -- or from flavored retail e-liquids containing 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, the release said.

And 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 scientists found.

They said their work adds to a growing body of research on the potential toxicity and impact of e-cigarettes on health reported by the American Heart Association Tobacco Regulation and Addiction Center, for which the University of Louisville is the flagship institute.


Carll and his colleague Matthew Nystoriak, an associate professor of medicine at the University of Louisville, received funding in June from the National Institutes of Health for research to determine the effects of vape flavorings on the heart.

Earlier this month, the Food and Drug Administration published its annual National Youth Tobacco Survey, which found that more than 2.5 million high and middle school students use e-cigarettes.

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