San Francisco, Nov 16 (IANS): E-cigarettes and marijuana have similar harmful effects on the heart as tobacco cigarettes, opening the door to abnormal heart rhythms, a new study has revealed.

According to the study published in the journal Heart Rhythm, smoking tobacco increases the risk of developing arrhythmias among other adverse cardiovascular effects.

Since e-cigarettes and heated tobacco products are perceived as less harmful than smoking, they have become increasingly popular.

"We found that cigarettes, e-cigarettes, and marijuana greatly interfere with the electrical activity, structure, and neural regulation of the heart," said lead author Huiliang Qiu, MD, PhD, a postdoctoral scholar in the UCSF Division of Cardiology.

In the study, researchers exposed rats for eight weeks to a single daily session of exposure to traditional cigarette smoke, aerosol ("vapour") from the e-cigarette, aerosol from the heated tobacco product, smoke from marijuana cigarettes, and smoke from modified marijuana that lacks all cannabinoids, compared to just air.

It was observed that rats exposed to the products (but not the air) had progressively worse heart function and increased blood pressure during this period, said the study.

After completing the study, the researchers conducted various tests on the hearts to determine how they functioned electrically and physically.

At the end of the study, it was found that all the products increased scarring in the hearts, reduced blood vessel numbers, changed nerve types in the heart, decreased the ability to vary heart rate, and increased the likelihood of arrhythmias.

"It's notable that all of these tobacco and marijuana products had such similar effects. And what's really striking is that this was caused by a single realistic smoking/vaping session per day," said senior author Matthew Springer, PhD, a UCSF professor of cardiology.

"The bottom line is that e-cigarettes, heated tobacco products, and marijuana cigarettes still involve many of the potential harmful effects of smoking tobacco. None of these products should be assumed to be a harmless replacement for smoking. In other words, just breathe air," he added.