Scheme of atrial fibrillation (top) and sinus ...

Scheme of atrial fibrillation (top) and sinus rhythm (bottom). The purple arrow indicates a P wave, which is lost in atrial fibrillation. (Photo credit: Wikipedia)

Heart arrhythmia AF and alcohol

New research has been published in the Canadian Medical Association Journal.

People with heart disease who drink, even moderately, may have a slightly  increased risk of a common heart rhythm problem, a new study suggests. The study is not the first to link moderate drinking to the heart arrhythmia,  known as atrial fibrillation (AF). But it’s still not clear that the habit,  itself, is the problem.

Doctors have long known that a drinking binge can trigger an episode of AF,  in which the heart’s upper chambers begin to quiver instead of  contracting normally. In general, it’s thought that having one or two drinks per day is protective  against coronary heart disease – where cholesterol-containing “plaque” builds up  in the arteries. But modest drinking hasn’t been linked to a decreased risk of AF – and the  new findings suggest that when people already have heart issues, moderate  drinking is actually tied to more AF cases.

The study included  more than 30,000 older adults who either had clogged arteries, a history of  stroke or diabetes complications such as kidney disease. Most had coronary heart  disease.

Over about five years, people who drank occasionally or not at all developed  AF at a rate of about 1.5% each year. For moderate drinkers, the rate was  1.75 and for heavy drinkers, it was 2.1%.

The researchers looked at other factors, too – like age, weight and smoking  habits. But moderate drinking was still linked to a 14% increase in the  risk of AF.

“Recommendations about the protective effects of moderate alcohol intake in  patients at high risk of cardiovascular disease may need to be tempered with  these findings,” write the researchers, led by Dr. Yan Liang, of McMaster  University in Hamilton, Ontario. Still, a researcher not involved in the work doubted the link between  moderate drinking and AF.

One problem is separating out the effects of binge drinking, according to Dr.  Kenneth J. Mukamal, of Harvard University and Beth Israel Deaconess Medical  Center in Boston.

Liang and colleagues did do a separate analysis where they excluded people  who reported a history of binge drinking – having more than five drinks at a  time. And the results were similar. But, Mukamal said in an email, the study did not repeatedly measure binge  drinking habits over the five-year follow-up. So it’s impossible to know if  moderate drinkers’ AF episodes were related to binges. “The majority of binge-drinking episodes nationwide occur among otherwise  moderate drinkers,” Mukamal noted. What’s more, he said, the current study included patients who were involved  in two clinical trials testing blood pressure drugs. That’s a narrow group of people. “In large studies of general populations –  much more representative than these clinical trial participants – AF only  appears higher among heavy drinkers,” Mukamal said.

Atrial fibrillation arises from a problem in the heart muscle’s electrical  activity. It’s not immediately life-threatening, and in some cases, an AF  episode is short-lived and goes away on its own. The known risk factors for AF include older age, high blood pressure,  diabetes, obesity and hyperthyroidism.

According to Mukamal, it’s not surprising that moderate drinking seems to  offer no protection against AF. The ways in which alcohol might cut the risk of coronary heart disease –  through better “good” cholesterol levels and less blood clotting – don’t affect  the risk of developing AF.

In general, experts say that if you’re already a moderate drinker (up to one  drink a day for women, and two for men), it’s probably okay to keep it up. But for people with certain chronic health problems, the new results may  question that guidance, the researchers said.

“And binge drinking should be avoided, even if you drink infrequently.”

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This entry was posted on Thursday, October 4th, 2012 at 7:13 pm and is filed under Symptoms of Heart Failure.
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