May 25, 2021 -- Even one drink of alcohol can increase the risk of heart rhythm problems in people with irregular heartbeat, according to an innovative study presented May 17 at the recent American College of Cardiology meeting.

Researchers from the University of California San Francisco recruited 100 people with the heart rhythm disorder, atrial fibrillation, who drank alcohol at least once a month. The participants were fitted with wearable patches to monitor their heart rhythm as well as an ankle bracelet that could detect alcohol through the skin – one used by law enforcement in people convicted of DUIs.

Every time study participants consumed alcohol, they pressed a button on their heart monitor to time stamp their drinking. The ankle bracelet and blood tests at 2 and 4 weeks served to corroborate the time stamp.

The risk for an episode of atrial fibrillation was highest within 3-4 hours of drinking alcohol, but lasted up to 9 hours. The risk of AF was higher the more alcohol participants drank.

“Is there an amount of alcohol that is safe? We couldn't identify such a threshold effect, although there's the important caveat that this was not a general population we were studying, but rather people who had a previous diagnosis of AF,” lead investigator Gregory M. Marcus, MD, a cardiologist at UCSF said in an interview with Medscape.

"This is just a fantastic study design and really addresses this problem headon because for many years we kind of debated back and forth with observational studies and all the limitations that come with it. But this is, I think, a very clear nail in the coffin," Dhanunjaya Lakkireddy, chair of the ACC Electrophysiology Council, said during a discussion of the results.

Previous research has shown that chronic drinking increases the risk of atrial fibrillation but this is the first study to show an immediate risk in the hours after drinking alcohol.

"If you really want to do everything you can to avoid AF, you probably should abstain from alcohol or at least minimize consumption," Marcus advised.

But he did acknowledge that “many of the reasons we treat arrhythmias at all is primarily to help with quality of life. We can't ignore the fact that alcohol — a good glass of wine — can be important to people's quality of life as well.”