AFib is an irregular and often rapid heart rate that can lead to heart-related problems, such as blood clots, stroke, and heart failure. Existing observational studies and literature reviews have shown that regular moderate alcohol consumption may increase the risk of this condition. However, its effect on atrial remodeling has not yet been fully understood.
A team of Australian researchers sought to determine the effect of various degrees of alcohol intake on atrial remodeling. To do this, the research team used high-density electroanatomic mapping which showed electrical and structural changes in the participants' left atria, which is the upper-left chamber of the heart. These changes indicate the severity of AFib.
For the study, they recruited 75 individuals with AFib. They divided the participants into three groups, according to the degree of their alcohol consumption. Twenty-five of the participants were lifelong nondrinkers, 25 were light drinkers, and the remaining 25 were moderate drinkers. Participants who consume two to seven alcoholic drinks per week were considered mild drinkers, while those who drink eight to 21 drinks per week were considered moderate drinkers.
Based on their analysis, the Australian research team found that participants who drank alcohol in moderation displayed more electrical evidence of scarring and impairments in electrical signaling compared with those who consumed alcohol lightly and those who abstained.
"Regular moderate alcohol consumption, but not mild consumption, is an important modifiable risk factor for AF associated with lower atrial voltage and conduction slowing," said Peter Kistler, lead researcher of the study.
The researchers said that these changes in electrical signaling and structures may be the reason behind regular drinkers' propensity to AFib. The findings of this study were published in the journal HeartRhythm.
"It is an important reminder for clinicians who are caring for patients with AF to ask about alcohol consumption and provide appropriate counselling in those who over-indulge," suggested Kistler.
Another research showed that moderate drinking may not really be beneficial for the heart. Published in the Journal of Studies on Alcohol and Drugs, this review looked at 45 cohort studies that reported drinking alcohol in moderation may have positive health benefits. The review confirmed that people who drink moderately at the time they were included in the studies did have a reduced risk of heart disease mortality; however, the outcomes changed when it investigated people's drinking habits at a younger age. (Related: Challenge studies that encourage moderate alcohol consumption for health and longevity.)
Studies that included participants 55 years old and below, who were followed into older age, did not find any correlation with alcohol. In addition, studies that assessed the participants' heart health at baseline showed no benefits from alcohol.
The authors note that the "nondrinkers" included in the studies were actually former drinkers who quit because of poor health. The authors suggest that these nondrinkers may have chosen to quit because their health was already poor.
Conversely, the older participants who consumed alcohol regularly were healthy not because they drink, but because they were already in good health and had no reason not to drink.
"We know that people generally cut down on drinking as they age, especially if they have health problems. People who continue to be moderate drinkers later in life are healthier. They're not sick, or taking medications that can interact with alcohol," said study researcher Tim Stockwell, of the University of Victoria in Canada.
Nonetheless, Stockwell noted that their review does not prove causality and does not intend to prevent moderate drinkers from drinking.