Studies have shown that small amounts of alcohol could reduce the incidence of coronary disease. However, a recent review found that the benefits of alcohol do not apply to atrial fibrillation. In fact, the researchers noted that alcohol was a risk factor for atrial fibrillation, also known as an irregular heartbeat.
Lead researcher Peter Kistler, PhD, of Baker IDI Heart and Diabetes Institute and the Alfred Hospital in Melbourne, Australia, and colleagues published their results online in the Journal of the American College of Cardiology on Dec. 5.
“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 news release. “The results are significant, because, 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.”
The researchers cited data that indicated 53 percent of Americans consumed alcohol on a regular basis, and 44 percent of drinkers consumed five or more standard drinks on a single occasion in the past month.
The defined light alcohol consumption as less than seven standard drinks per week, moderate alcohol consumption as seven to 21 standard drinks per week and heavy alcohol consumption as more than 21 standard drinks per week. They considered one standard drink as approximately 12 grams of alcohol.
The review, which included nearly 900,000 people, found that there was an 8 percent increase in the risk of atrial fibrillation for each alcoholic drink consumed each day.
The researchers mentioned that there was no safe level of daily alcohol intake in patients with a history of atrial fibrillation, although they noted that their recommendation was based on observational and nonrandomized studies.
“People who continue to consume alcohol at moderate rates may also notice their irregular heartbeats become more frequent,” Kistler said. “This is concerning, because it can lead to serious issues, such as heart failure and stroke. So, even though we do not have randomized data that tells us what a ‘safe’ amount is to consume, people with an irregular heart beat should probably drink no more than one alcoholic drink per day with two alcohol free days a week.”
The researchers also wrote that alcohol was independently associated with atrial fibrillation, but they mentioned alcohol’s interaction with other risk factors could be misunderstood. For instance, they said that hypertension, obesity, obstructive sleep apnea and cardiomyopathy could be caused or exacerbated by alcohol.
They mentioned that future research should examine alcohol’s contribution to obesity, sleep disordered breathing and hypertension and should evaluate whether patients with atrial fibrillation need to avoid alcohol.
“Alcohol is an important risk factor for AF through direct effects on the atrial substrate, and by contributing to hypertension, obesity, and [sleep-disordered breathing,” the researchers wrote. “Habitual drinking at moderate levels, as well as binge drinking, predisposes to [atrial fibrillation], with an increase in [atrial fibrillation] recurrence in those who continue to drink. Although a small amount of alcohol is considered cardioprotective, these benefits do not extend to [atrial fibrillation].”