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E-cigarettes with nicotine increase adrenaline levels in nonsmokers’ hearts
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Healthy nonsmokers who used electronic cigarettes with nicotine had abnormal heart rate variability indicative of increased adrenaline levels in their hearts, according to a study published in the Journal of the American Heart Association.
Abnormal heart rate variability in this same pattern has been shown to be associated with increased cardiac risk in populations with and without known heart disease.
“It’s reassuring that the non-nicotine constituents in electronic cigarette vapor or aerosol don’t cause [abnormal heart rate variability],” Holly R. Middlekauff, MD, professor of medicine (cardiology), professor of physiology and assistant dean of student affairs at the David Geffen School of Medicine at UCLA, told Cardiology Today. “On the other hand, it’s concerning that electronic cigarettes with nicotine do cause this pattern, and the finding really pinpoints the nicotine as the instigator.”
Middlekauff and colleagues analyzed data from 33 participants (mean age, 26 years; 13 men) who did not smoke e-cigarettes or tobacco cigarettes for at least 1 year, were not exposed to secondhand smoke, were not obese and had no known health problems.
Participants used an e-cigarette with nicotine, one without nicotine or an empty cigarette as a control during three different sessions, each separated by a 4-week washout. During the sessions, heart rate variability was monitored by ECG, and blood tests were performed to analyze various antioxidant parameters and the enzymatic activity of human plasma PON1.
Cardiac sympathovagal balance shifted significantly toward sympathetic predominance when participants used e-cigarettes with nicotine, which was not seen in e-cigarettes without nicotine, according to the researchers.
E-cigarettes with nicotine decreased the high-frequency component, increased the low-frequency component and increased the ratio of low frequency and high frequency vs. e-cigarettes without nicotine and the control cigarette.
Heart rate increased more after e-cigarettes with nicotine. There was no difference in heart rate after e-cigarettes without nicotine and the control cigarette, according to the study.
Changes in inflammation or oxidative stress did not differ when comparing e-cigarettes with and without nicotine with the control, although only a limited number of markers were tested.
“There is evidence from other studies to support the idea that electronic cigarettes are not as harmful as tobacco cigarettes, so my advice to current tobacco cigarette smokers is that switching to an electronic cigarette may be a better choice,” Middlekauff told Cardiology Today. “However, electronic cigarettes should probably be used for as short a time as possible since there’s concern about persistently lifelong increased adrenaline levels in the heart,” “If you don’t smoke, I feel very strongly that you shouldn’t start using an electronic cigarette because the evidence is mounting that electronic cigarettes are not harmless.” – by Darlene Dobkowski
For more information:
Holly R. Middlekauff, MD, can be reached at hmiddlekauff@mednet.ucla.edu.
Disclosure: The authors report no relevant financial disclosures.
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