Alcohol's toll on the heart: bigger, not better

Drinking alcohol, even in moderate amounts, may increase the size of the heart's left atrium, a new study finds.

The left atrium is one of the two upper chambers of the heart, along with the right atrium. When it is enlarged, a person is at risk for developing a type of irregular heartbeat called atrial fibrillation, which can, in turn, lead to other problems, including stroke.

"Despite the widely held belief by the public that alcohol has a beneficial effect on general heart health, acute alcohol consumption has long been linked to the development of [atrial fibrillation]", the researchers, led by Dr. David McManus, director of the Atrial Fibrillation Treatment Program at UMass Memorial Health Care in Massachusetts, wrote in their report.

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Indeed, previous studies have suggested that alcohol may be associated with atrial fibrillation. However, it was unclear exactly how the two were linked, according to the new findings, published today Sept. 14 in the Journal of the American Heart Association.

To investigate, the researchers looked at data from more than 5,200 people who were enrolled in either the Framingham Heart Study or were the children of people in the Framingham Heart Study. The Framingham Heart Study is a large, ongoing study that began in 1948, and its aim is to look at heart disease risk factors. The study participants live or lived in Framingham, Massachusetts.

The participants in the study reported how much alcohol they drank, on average, each week. In addition, all of the participants had imaging tests to look at the size of their hearts, and were tested for atrial fibrillation, according to the study.

At the beginning of the study, the participants were, on average, 56 years old. The average follow-up period was about six years, according to the researchers.

Over the study period, the researchers found that every additional 10 grams of alcohol (just less than one drink) consumed daily was linked to a 0.16-millimeter (0.006 inches) increase in the diameter of the left atrium.

The finding suggests that enlargement of the left atrium may be the factor linking alcohol to atrial fibrillation.

Other studies have shown that regularly drinking two or more drinks a day is linked to a 30 percent higher risk of atrial fibrillation, the researchers wrote.

Atrial fibrillation increases a person's risk of stroke, because it allows blood to pool in the heart. A clot can form in the pooled blood and, in turn, travel up to the brain and cause a stroke.

In addition, a recent meta-analysis found that atrial fibrillation also may be linked to a number of other conditions throughout the body, including heart failure and kidney disease.

Originally published on Live Science.