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Just a drink a month may put those with atrial fibrillation at risk

In people who had an atrial fibrillation episode, it was about twice as likely that they had had alcohol in the four hours before the episode, found a small study from the University of California.

Atrial fibrillation is the most common cardiac arrhythmia. Long-term alcohol use has been associated with remodelling of the heart atria and development of atrial fibrillation. Avoiding alcohol has also been associated with reduced atrial fibrillation. The specific relationship between an alcoholic drink and atrial fibrillation is difficult to figure out because of how commonly alcohol is consumed.

Why did the researchers do this particular study?
Researchers were interested in the specific association between drinking alcohol and the risk for an episode of atrial fibrillation soon afterward.

Who was studied?
A total of 100 adults with paroxysmal (intermittent) atrial fibrillation who drank an average of one drink per month were recruited from cardiology clinics at the University of California, San Francisco.

How was the study done?
Each patient wore an electrocardiogram monitor for four weeks. The monitor recorded the time and length of each episode of atrial fibrillation. Patients were asked to press a button on the monitor every time they had a drink. They also wore a sensor around their ankle that measures alcohol consumption. At two and four weeks, patients had their device checked and a fingerstick blood test to measure alcohol use. For each patient, the analysis compared the number of episodes of atrial fibrillation that were preceded by a drink of alcohol and the number of episodes that were not. This method of using each patient as his or her own control reduces the chance that other factors, such as age, other medical conditions, or medications, may affect the likelihood of atrial fibrillation. The analyses accounted for differences by day of week and time of day.

What did the researchers find?
Of the patients, 56 had an atrial fibrillation episode and thus were included in the analysis. In people who had an atrial fibrillation episode, it was about twice as likely that they had had alcohol in the four hours before the episode. The association was slightly more with more drinks and with a six-hour time frame, but it decreased with longer time frames. Additional analyses to account for all atrial fibrillation episodes reduced the association, but the pattern and statistical significance of findings were similar. Findings were similar when alcohol concentration was measured using the wearable monitor: atrial fibrillation was more likely to be seen within hours of alcohol detected by the alcohol sensor.

What were the limitations of the study?
This is a small study that may not be generalisable beyond the types of patients it included. The participants may have characteristics that make them more susceptible to alcohol than others. Despite the analyses and use of the same person as the control, there may still be other factors that may be associated with both alcohol and atrial fibrillation that were not accounted for. The modest effect of alcohol on atrial fibrillation may not translate to other cardiovascular diseases. There were still episodes of atrial fibrillation not preceded by alcohol drinking. Although alcohol may be associated with individual atrial fibrillation events in people with paroxysmal atrial fibrillation, it may be one of many factors.

What are the implications of the study?
Alcohol may be a modifiable exposure associated with individual and nearly immediate atrial fibrillation events in patients with paroxysmal atrial fibrillation.

Study details

Acute Consumption of Alcohol and Discrete Atrial Fibrillation Events

Gregory M. Marcus, Eric Vittinghoff, Joshua D. Moss, Isaac R. Whitman, Sean Joyce, Vivian Yang, Gregory Nah, Randall J. Lee, Edward P. Gerstenfeld, Byron K. Lee, Zian H. Tseng, Vasanth Vedantham, Jeffrey E. Olgin, Melvin M. Scheinman, Henry Hsia, Rachel Gladstone, Shannon Fan, Emily Lee, Christina Fang, Kelsey Ogomori, Robin Fatch, Judith A. Hahn,

Published in Annals of Internal Medicine on 31 August 2021

Patients' self-reports suggest that acute alcohol consumption may trigger a discrete atrial fibrillation (AF) event.

To objectively ascertain whether alcohol consumption heightens risk for an AF episode.

Consenting patients with paroxysmal AF.

Participants were fitted with a continuous electrocardiogram (ECG) monitor and an ankle-worn transdermal ethanol sensor for 4 weeks. Real-time documentation of each alcoholic drink consumed was self-recorded using a button on the ECG recording device. Fingerstick blood tests for phosphatidylethanol (PEth) were used to corroborate ascertainments of drinking events.

Of 100 participants (mean age, 64 years [SD, 15]; 79% male; 85% white), 56 had at least one episode of AF. Results of PEth testing correlated with the number of real-time recorded drinks and with events detected by the transdermal alcohol sensor. An AF episode was associated with 2-fold higher odds of one alcoholic drink (odds ratio [OR], 2.02 [95% CI, 1.38 to 3.17]) and greater than 3-fold higher odds of at least 2 drinks (OR, 3.58 [CI, 1.63 to 7.89]) in the preceding 4 hours. Episodes of AF were also associated with higher odds of peak blood alcohol concentration (OR, 1.38 [CI, 1.04 to 1.83] per 0.1% increase in blood alcohol concentration) and the total area under the curve of alcohol exposure (OR, 1.14 [CI, 1.06 to 1.22] per 4.7% increase in alcohol exposure) inferred from the transdermal ethanol sensor in the preceding 12 hours.

Confounding by other time-varying exposures that may accompany alcohol consumption cannot be excluded, and the findings from the current study of patients with AF consuming alcohol may not apply to the general population.

Individual AF episodes were associated with higher odds of recent alcohol consumption, providing objective evidence that a modifiable behaviour may influence the probability that a discrete AF event will occur.


Annals of Internal Medicine article – Summary for Patients: Alcohol Drinking and Atrial Fibrillation (Open access)


Annals of Internal Medicine study details – Acute Consumption of Alcohol and Discrete Atrial Fibrillation Events (Open access)


See more from MedicalBrief archives:


Linking diet and alcohol, breast cancer and heart disease


Moderate drinking not associated with increased heart or death risk — Large UK analysis


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