Excessive alcohol consumption is an established risk factor for atrial fibrillation (AF) but a new study has found that even moderate alcohol consumption results in more electrical evidence of scarring and impairments in electrical signalling compared with non-drinkers and light drinkers. 

AF is an abnormal heart rhythm characterised by rapid and irregular beating of the atria. The study published in HeartRhythm, the official journal of the Heart Rhythm Society and the Cardiac Electrophysiology Society, showed that regular moderate alcohol consumption (an average of 14 glasses per week) was a modifiable risk factor for AF. 

The purpose of this study was to determine the impact of different degrees of alcohol consumption on atrial remodelling using high-density electroanatomic mapping. In this multi-centre cross-sectional study in Australia, investigators performed detailed invasive testing on the atria of 75 patients with AF, 25 in each of three categories: lifelong non-drinkers, mild drinkers, and moderate drinkers.

Patients self-reported their average alcohol consumption in standard drinks per week (one standard glass is around 12 grams of alcohol) over the preceding 12 months. Patients consuming two to seven drinks per week were considered mild drinkers, while those consuming eight to 21 drinks per week (average 14 drinks per week) were defined as moderate drinkers.

The investigators found that individuals who consumed moderate amounts of alcohol (average 14 drinks per week) had more electrical evidence of scarring and impairments in electrical signalling than non-drinkers and light drinkers.

"This study underscores the importance of excessive alcohol consumption as an important risk factor in AF," said lead investigator Professor Peter Kistler from the Heart Centre, Alfred Hospital, Melbourne, Australia. "Regular moderate alcohol consumption, but not mild consumption, is an important modifiable risk factor for AF associated with lower atrial voltage and conduction slowing. These electrical and structural changes may explain the propensity to AF in regular drinkers. It is an important reminder for clinicians who are caring for patients with AF to ask about alcohol consumption and provide appropriate counselling in those who over-indulge."