Can a Coffee a Day Keep AFib Away?

A cup of coffee a day did not worsen atrial fibrillation (AF) in adults recovering from electrical cardioversion, and it may even lower the likelihood of recurrent arrhythmia, according to new findings presented at the American Heart Association (AHA) 2025 Scientific Sessions.1

Contradicting longstanding clinical advice to avoid caffeine, new randomized data suggest moderate coffee consumption may be associated with fewer AF or atrial flutter episodes during the 6 months following cardioversion. The Does Eliminating Coffee Avoid Fibrillation? (DECAF) trial (NCT05121519), simultaneously published in JAMA, enrolled adults who typically consume about 1 cup of caffeinated coffee per day and evaluated whether continuing or avoiding caffeine influences rhythm stability after treatment.2

“The present trial, where measured and unmeasured confounders should have been balanced via randomized allocation, suggests that caffeinated coffee consumption may reduce recurrence of persistent AF compared with abstinence from coffee and other caffeinated products,” the researchers said. “Moreover, a continued separation of survival curves over time implies that this difference may be more attributable to a benefit of coffee consumption rather than harm from abrupt coffee cessation and withdrawal.”

Patients drinking coffee had a 39% lower risk of AF recurrence in the DECAF trial. | Image credit: Farknot Architect – stock.adobe.com

DECAF Trial Participants Mostly White Males

The international, multicenter trial recruited 200 adults with AF scheduled for direct-current or pharmacologic cardioversion across 5 sites in the US, Australia, and Canada. The average age of participants was 69 years; overall, 71% were men, and 80% identified as White. All participants drank at least 1 cup of coffee per day in the 5 years preceding enrollment, and did not necessarily have to be current coffee drinkers to be eligible.

Following successful electrical cardioversion, patients were randomized 1:1 to either continue their daily caffeinated coffee habit or abstain from all caffeine for 6 months. Roughly half were taking antiarrhythmic medications at baseline, which they maintained throughout the study. Researchers collected data on caffeine intake through structured phone interviews and verified arrhythmia recurrences using medical-grade electrocardiograms (ECGs) or clinician documentation.

Coffee Drinkers Had Fewer AF or Flutter Episodes

During 6-month follow-up, 56% of patients experienced recurrent AF or atrial flutter lasting more than 30 seconds. However, recurrence differed between groups: 47% of daily coffee drinkers experienced an episode compared with 64% of those instructed to avoid all caffeine. These differences translated to a 39% lower risk of recurrence among the coffee group (HR, 0.61; 95% CI, 0.42-0.89; P = .01).

This benefit seemed to be consistent across most subgroup analyses except for ablation history (P = .04), though the authors noted this was not adjusted for multiplicity and should be interpreted cautiously.

“Our study results suggest that caffeinated coffee may not be responsible for raising the risk of AFib and may even reduce it,” said study author Gregory M. Marcus, MD, MAS, professor of medicine at the University of California, San Francisco.1

How Does Coffee Affect AF Risk?

There are several reasons why coffee drinkers in the trial may have experienced fewer AF recurrences. Caffeinated coffee consumption can result in blockage of A1 and A2a adenosine receptors, the authors explained, which may reduce AF triggers by limiting adenosine-mediated atrial excitability.2 Coffee also has documented anti-inflammatory effects, and lower systemic inflammation may contribute to lower AF risk. Caffeine’s catecholaminergic activity and mild diuretic properties could also reduce AF susceptibility by influencing autonomic tone or blood pressure.

Behavioral factors can play a role as well. Although some dietary habits differed between groups, prior randomized data show that drinking coffee can increase daily physical activity, a separate modifiable risk factor that can decrease AF recurrence. Together, these mechanisms suggest that typical amounts of naturally caffeinated coffee may have multiple physiologic and lifestyle effects that could influence rhythm stability, though the current findings should not be applied to high-dose caffeine or energy drinks.

Baseline Differences and Other Limitations

It’s important to note the several limitations of the DECAF trial. Because the trial used a pragmatic design, AF or atrial flutter recurrences were identified through routine clinical care rather than a standardized monitoring schedule. Additionally, though many participants used wearable ECG devices, detection was not uniform, and the coffee-drinking group reported more wearable ECG use. The modest sample size of 200 patients also leaves open the possibility of a chance finding in this cohort, and the study not being blinded could influence symptom reporting or care-seeking behavior.

There were also some clear differences in baseline characteristics that may have contributed despite adjusted analyses. The caffeine abstinence group was 2 years older on average and included more women (n = 35 vs 24), White patients (88 vs 77), and patients with a high school degree or less education (41 vs 29) than the coffee drinking group.

Patients in the abstinence group were also more likely to have a history of coronary artery disease (16 vs 9), paroxysmal AF (35 vs 25), and coexisting atrial flutter (8 vs 3). Patients in the coffee drinking group were more likely to have undergone previous AF ablation (20 vs 12) and drank more tea before the trial (37 vs 28) than those in the abstinence group.

References

1. Cup of coffee a day may not be harmful for some adults with AFib and could lower episodes. News release. American Heart Association. November 9, 2025. Accessed November 13, 2025. https://newsroom.heart.org/news/cup-of-coffee-a-day-may-not-be-harmful-for-some-adults-with-afib-and-could-lower-episodes
2. Wong CX, Cheung CC, Montenegro G, et al. Caffeinated coffee consumption or abstinence to reduce atrial fibrillation: the DECAF randomized clinical trial. JAMA. Published online November 9, 2025. doi:10.1001/jama.2025.21056