DENVER — Consumption of as little as one alcoholic drink per day is associated with increased risk of atrial fibrillation and atrial flutter in persons aged 60 or younger, Dr. Gregory M. Marcus said at the annual meeting of the Heart Rhythm Society.
In contrast, regular alcohol intake—defined as one or more drinks per day—was not associated with significantly increased risk of atrial fibrillation (AF) or atrial flutter in individuals aged older than 60 years in his case-control study. That doesn't mean he dismisses it as a culprit in the older age group.
“I don't think that alcohol doesn't cause problems in the older age group. But older populations have other very prevalent risk factors. Age itself is a risk factor for AF, as is hypertension, which is common. So it may be that the true association between alcohol and AF is lost or diluted in the older population, whereas it can be more easily seen in the younger population,” said Dr. Marcus, an electrophysiologist at the University of California, San Francisco. Pending further study, it makes sense for patients with AF or atrial flutter to try to avoid alcohol altogether, he said in an interview.
His case-control study involved 195 consecutive patients with AF or atrial flutter, two-thirds of whom were aged 60 or younger, and 186 controls, three-quarters of whom had supraventricular tachycardia, while the rest were healthy.
One in five study participants was a regular drinker. Four-fifths of them fell within the 1–2 drinks per day category generally classified as moderate drinking, which is often recommended as cardioprotective.
After adjustment for potential confounders including age, gender, race, coronary artery disease, hypertension, and heart failure in a multivariate regression analysis, individuals aged 60 or younger with AF or atrial flutter who drank alcohol daily were 4.5 times more likely to have AF or atrial flutter compared with arrhythmia-free controls, and 2.5 times more likely to have AF or flutter compared with patients with supraventricular tachycardia.
There was a linear association between the average amount of alcohol consumed per day and risk of AF or flutter, with an increased risk seen beginning at an average intake of 1–2 drinks daily. This dose-response relationship was statistically significant for atrial flutter and approached significance for AF.
The mechanism for the observed association between moderate drinking and increased risk of AF and atrial flutter remains uncertain. However, there are preliminary data suggesting that alcohol reduces the atrial effective refractory period, which would be expected to have an atrial arrhythmogenic effect, Dr. Marcus said.
Prior studies have linked binge drinking to increased risk of AF. Some studies have been negative, but they were done predominantly in older populations, which was one reason Dr. Marcus chose to look specifically at risk in patients aged younger than 60. The relationship between alcohol intake and atrial flutter had not been examined prior to this study.
There was a linear association between the average amount of alcohol consumed per day and risk of AF or flutter. DR. MARCUS