Even moderate alcohol consumption, described as intake of two drinks daily or 14 per week, could increase the risk of irregular heart rhythm condition, warn researchers.

The team from the Alfred Hospital in Melbourne, Australia, found that regular moderate alcohol consumption (an average of 14 glasses per week) results in more electrical evidence of scarring and impairment in electrical signalling compared with non-drinkers and light drinkers. 

Alcohol consumption is therefore an important modifiable risk factor for atrial fibrillation -- an abnormal heart rhythm characterised by rapid and irregular beating of atria -- upper chamber of the heart, the researchers said. 

"Regular moderate alcohol consumption, but not mild consumption, is an important modifiable risk factor for atrial fibrillation associated with lower atrial voltage and conduction slowing," said lead investigator Peter Kistler, Professor from the Heart Centre at Alfred Hospital. 

"These electrical and structural changes may explain the propensity to atrial fibrillation in regular drinkers. It is an important reminder for clinicians who are caring for such patients to ask about alcohol consumption and provide appropriate counselling in those who over-indulge," he added.

In the study, published in the journal HeartRhythm, the team determined the impact of different degrees of alcohol consumption on atrial remodelling using high-density electroanatomic mapping. 

They performed detailed invasive testing on the atria of 75 patients with atrial fibrillation, 25 in each of three categories: life-long non-drinkers, mild drinkers and moderate drinkers.