In order to live healthier and smoke less or to quit smoking completely, many people switch to e-cigarettes. However, nicotine in e-cigarettes is far from harmless and is more harmful in certain types of e-cigarettes than others. These can also increase the risk of cardiac arrhythmias.
A new study involving experts from the University of Louisville School of Medicine (ULSOM) examined how different forms and concentrations of nicotine influence e-cigarette-induced cardiac dysfunction and arrhythmogenesis. The results are published in the journal “Nicotine & Tobacco Research”.
Nicotine in e-cigarettes harmless?
At the beginning of the year, many smokers resolve to quit smoking or at least smoke less. E-cigarettes seem to be a helpful approach here, as nicotine is considered relatively harmless, while additives and combustion products are primarily blamed for the damage caused by conventional cigarettes, the team reports.
However, recent studies have suggested that the use of e-cigarettes can promote cardiac arrhythmias, with nicotine apparently playing a crucial role, the researchers continued. The team now tried to determine possible connections using mice.
To do this, the team exposed mice to so-called aerosols that contained different forms and concentrations of nicotine. We then examined how the nicotine affected the animals’ heart rate and heart rate variability.
Danger from nicotine salts
It was found that so-called nicotine salts in particular were associated with more severe cardiac arrhythmias, with increased nicotine concentrations contributing to an increase in cases of cardiac arrhythmias. Nicotine salts are used, for example, in Juul and other pod-based e-cigarettes, the researchers explain.
It has also been shown that the higher concentrations of nicotine salts increase the activity of the sympathetic nervous system and also the heart rate. This is because nicotine salts stimulate the same receptor that is inhibited by beta-blockers and heart medications.
The study results “suggest that nicotine is harmful to the heart and contradicts widespread claims that nicotine itself is harmless,” said study author Dr. Alex Carll in a press release.
Nicotine type and concentration influence the harmful cardiovascular effects of e-cigarette aerosols, which could have important regulatory implications, the doctor adds.
Irregular heartbeats caused by nicotine in e-cigarettes
“The nicotine in e-cigarettes causes dose-dependent irregular heartbeats (arrhythmias) by stimulating the very receptor that many heart medications are designed to inhibit,” emphasizes Dr. Carll.
According to the researchers, the results suggest that inhaling e-cigarette aerosols from e-liquids containing nicotine salts could increase cardiovascular risks by causing sympathetic dominance and cardiac arrhythmias.
Cardiac arrhythmias caused by aromas or solvents
An earlier study by the research group had already shown that e-cigarette aerosols that contain certain flavors or solvents can cause cardiac arrhythmias and other impairments in the heart, even without nicotine.
This prompts Dr. Carll suspects that not only the nicotine in e-cigarettes, but also the flavors and solvents they contain may increase the risk of cardiac arrhythmias.
If the new findings are confirmed in studies on humans, regulating nicotine salts through minimum pH standards or limiting acid additives in e-liquids could significantly reduce the health risks of using e-cigarettes, the researchers emphasize. (as)
