Alcohol and your heart: Just getting a buzz can trigger an irregular rhythm

A half-full beer glass remains on a table at the Dispensary pub in Liverpool, England, Monday Oct 12, 2020. (AP Photo/Jon Super)

The effects of alcohol on your heart can be immediate, triggering an irregular rhythm called atrial fibrillation or AFib, according to new state-of-the-art research.

"Ours is the first study to point to a mechanism through which a lifestyle factor can acutely change the electrical properties of the heart to increase the chance of an arrhythmia," said study author Dr. Gregory Marcus, the associate chief of cardiology for research at the University of California, San Francisco.

The research on atrial fibrillation, published Wednesday in the Journal of the American College of Cardiology: Clinical Electrophysiology, was unique because it was a randomized, double-blinded clinical study -- considered the "gold standard" in research.

Marcus and his team put 100 heart patients with diagnosed AFib -- the most common life-threatening heart-rhythm disorder -- under anesthesia and then injected them with enough booze to bring their blood alcohol level to .08 per cent -- just above the legal limit in the United States.

The change they saw was startling: Alcohol appeared to immediately affect the heart's natural recovery period in a way that could trigger an atrial fibrillation event.

"The electrical changes we observed in the pulmonary veins ... would enhance both the chance that atrial fibrillation will occur immediately, and would be maintained," Marcus said.

"It is a first-in-human demonstration of the immediate effects of alcohol, directly on the heart," said Dr. Marco Perez, director of the Inherited Cardiac Arrhythmia Clinic at Stanford University Medical Center, who was not involved in the research.

"This study, however, does not address the question of whether or not moderate drinking is 'good or bad' for the heart, particularly in the long-term," Marcus added. "It merely helps us understand the possible mechanisms behind the observations that people who drink have higher rates of arrhythmias."

A GROWING CONCERN

AFib is an irregular heartbeat often described by many sufferers as a "quiver," "flutter" or "flip-flop" of the heart in the chest.

Atrial fibrillation is the leading cause of stroke in the United States, according to the U.S. Center for Disease Control and Prevention. In addition, strokes connected to AFib tend to be "more severe than strokes with other underlying causes," the CDC said.

It can lead to blood clots, heart failure and other heart-related complications.

"It also can increase the risk for heart attack, for dementia, for kidney disease. All of those things are likely long term risks," Marcus said.

At least 2.7 million Americans are living with AFib, according to the American Heart Association. Many of those suffer chest pain, palpitations, shortness of breath and fatigue. But for others, AFib is symptomless, a potentially silent killer.

The rate of AFib in the U.S. population is growing: The CDC estimates some 12.1 million Americans will have AFib by 2030. In Europe, some 17.9 million are expected to suffer from the condition by 2060.

"Age is one of the most important risk factors, so with the aging of the population it's becoming more common," Marcus said.

The epidemic of obesity is also contributing to the growing numbers, along with other risk factors such as high blood pressure, diabetes, chronic kidney disease, smoking and yes, drinking alcohol.

"There's a long history now of evidence that alcohol may increase the risk for atrial fibrillation, contrary to the findings regarding coronary artery disease or risks of heart attack," Marcus said.

That, of course, flies in the face of what we have often been told in the past -- drinking in moderation might actually help the heart.

"This is a critically important distinction," Marcus said. "Many in the lay public easily conflate different forms of heart disease -- making the assumption when one refers to heart disease, they mean a heart attack or a blockage of a coronary arteries supplying blood to the heart.

"So it may very well be the case that alcohol -- at least in moderation -- could be healthy for some types of heart disease and harmful for other types of heart disease," Marcus said.

IS ALCOHOL REALLY GOOD FOR THE HEART?

Some studies, however, are beginning to question the benefits of any alcohol for the heart.

"There are studies indeed reporting a benefit to moderate drinking, but these are not 'randomized, controlled' studies, and are likely confounded by the fact that people who engage in mild to moderate drinking may do other things (like exercise) that are good for the heart," Perez said in an email.

"However, there are some genetic studies that suggest that even modest alcohol use has a detrimental effect on clinical outcomes," Perez added.

It's possible that any heart benefit may be outweighed by other health risks, such as high blood pressure, pancreatitis, certain cancers and liver damage.

Women who drink are at a higher risk for breast cancer. Alcohol contributes about 6 per cent of the overall risk, possibly because it raises certain dangerous hormones in the blood.

Drinking can also increase the chance you might develop bowel, liver, mouth and oral cancers.

A 2018 study co-authored by University of Cambridge epidemiologist Steven Bell found that while drinking was beneficial in lowering the risk for heart attack, even one drink a day shortened life expectancy. Reducing alcohol use added one to two years to life expectancy at age 40, Bell said in a prior interview.

According to Bell, the "take-home message" from his study is that "people shouldn't drink under the belief that it will lower their risk of disease."

"And those of us who opt to drink should minimize our intake if we wish to prolong our life and well-being," Bell said.