Electronic Cigarettes Don't Adversely Affect Cardiac Function

August 25, 2012

August 25, 2012 (Munich, Germany) — The first study to look at the effects of smoking electronic cigarettes on the heart has found that they do not appear to have any acute adverse effects on cardiac function

"I can say that electronic cigarettes are not a healthy habit, but they are a safer alternative to tobacco cigarettes," Dr Konstantinos Farsalinos (Onassis Cardiac Surgery Center, Kallithea, Greece) told a press conference here at the European Society of Cardiology 2012 Congress. "Humans are made to inhale clean air, so I think everything else you inhale is not healthy; I cannot say this is absolutely healthy. The electronic cigarette is a tobacco-harm–reduction product, marketed as an alternative to smoking; they are not marketed for the nonsmoker to start using this device."

E-Cigarette: No Effect on Cardiac Function, But Slight Rise in Diastolic BP

However, he acknowledges the research--which compared the effects of electronic cigarettes on the heart with those of tobacco cigarettes, in less than 50 people--is preliminary, and much more study is needed into this relatively new phenomenon. This is only the second ever study to look at the clinical effects of electronic cigarettes; the first, reporting on pulmonary function, did show a short-term adverse effect of e-cigarettes [2], he noted.

Farsalinos explained that the electronic nicotine-delivery device, more commonly known as the electronic cigarette, has been marketed for several years; they were invented in 2003 by a Chinese pharmacist and are now used by millions worldwide as an alternative to smoking. But the devices are not regulated, and the World Health Organization has asked for clinical studies on their effects on human health.

Electronic cigarettes consist of a battery, a cartridge containing liquid, and a heating element that warms and evaporates the liquid to a vapor. The liquid commonly contains glycerol, propylene glycol, flavorings, and nicotine, and most laboratory analyses have shown this to contain no carcinogens and to be less toxic than regular cigarettes, he noted.

In his small study, Farsalinos and colleagues measured myocardial function using echocardiography before and after smoking one tobacco cigarette in 20 young daily smokers aged 25 to 45 years of age and before and after use of an electronic cigarette for seven minutes in 22 experienced users of the devices, who were of a similar age. The e-cigarettes used contained 11 mg/mL of nicotine (Nobacco, USA Mix) in the liquid, a "moderate" amount, said Farsalinos, who explained that the liquid in these devices can contain up to 23 mg/mL of nicotine.

The researchers also took measures of blood pressure and heart rate.

Smoking one tobacco cigarette led to acute, significant impairment of four parameters of left ventricular function, but electronic cigarettes had no acute adverse effects. Smoking tobacco cigarettes also led to significant elevations in blood pressure and heart rate (+8% systolic BP, +6% diastolic BP, and a 10% rise in heart rate) compared with a single elevation of around 4% in diastolic BP in the electronic-cigarette users.

Potential mechanisms explaining the differences include the fact that no combustion occurs in the e-cigarette and therefore the chemicals created and absorbed from it are less toxic and the fact that less nicotine is likely to be absorbed from electronic cigarettes than from tobacco ones, said Farsalinos.

E-Cigarettes Address Both Chemical and Behavioral Addiction

Farsalinos says e-cigarettes address both sides of a smoker's addiction: the chemical craving for nicotine, which has known effects on the brain, "and the psychological/behavioral addiction that comes from having something in your hand, lighting it up, seeing smoke, and inhaling and exhaling it." The latter has been shown in the literature to be just as much of a motivator for people to smoke as the nicotine addiction, he noted.

Hence, electronic cigarettes could help people to stop smoking, and preliminary studies indicate that this is the case, he said. "But the companies producing them have avoided this claim because they do not want them to be regulated as medical devices."