Regularly drinking even small amounts of alcohol may boost the risk of an irregular heartbeat known as atrial fibrillation, a new research review finds.

"The results are significant, since chances are, there are people who are consuming one to two glasses of alcohol per day that may not realize they are putting themselves at risk for irregular heartbeat," said study lead author Dr. Peter Kistler. He is head of clinical electrophysiology research at the Baker IDI Heart and Diabetes Institute in Melbourne, Australia.

Other research has linked light-to-moderate alcohol use (up to two standard drinks a day for men and one for women) to better heart health for some people. The new research suggests that this may not apply to atrial fibrillation, which boosts the risk of heart-related problems and stroke.

The authors of the new study reviewed prior research that tracked almost 900,000 people over 12 years. They found that the risk of atrial fibrillation grew by 8 percent for each daily alcoholic drink. The findings were similar for men and women.

The results appear Dec. 5 in the Journal of the American College of Cardiology.

"There has been a lot of attention in recent years about the benefits of drinking small amounts of alcohol for the heart," Kistler said in a journal news release.

"While moderate amounts of alcohol appear protective for the 'plumbing,' or blood supply to the heart muscle, the benefits of alcohol do not extend to the electrical parts of the heart, or heartbeat," he said.

The study doesn't establish a direct cause-and-effect relationship. Still, cell damage from habitual drinking may lead to small amounts of fibrous tissue within the heart that causes the irregular, quivering heartbeat, the study authors said.

People who continue to consume alcohol at moderate rates may also notice their irregular heartbeat becoming more frequent, Kistler noted.

"This is concerning, because it can lead to serious issues, such as heart failure and stroke," Kistler said. "So, even though we do not have randomized data that tells us what a 'safe' amount is to consume, people with an irregular heartbeat should probably drink no more than one alcoholic drink per day with two alcohol-free days a week."

The study authors called for more research to determine whether patients with an abnormal heartbeat should avoid alcohol altogether.