A new study demonstrates that people who drink an average of 1 cup of coffee per day have fewer instances of recurring atrial fibrillation (AF) — irregular heartbeat — than those who completely avoid coffee and caffeinated products. Christopher X. Wong, MBBS, MPH, PhD, from the University of California – San Francisco, presented these results on behalf of the DECAF (Does Eliminating Coffee Avoid Atrial Fibrillation?) trial investigators during a late-breaking clinical science session on Sunday at the American Heart Association (AHA) Scientific Sessions 2025 in New Orleans. The data were also published simultaneously in the Journal of the American Medical Association. Conventional wisdom has traditionally led people to think that coffee consumption can trigger AF and other arrhythmias. Investigators in the DECAF study created a randomized clinical trial to examine the impacts of caffeine on AF compared with abstinence from coffee. DECAF was a prospective, open-label, randomized trial that enrolled 200 patients (mean age=69 years, 71% male) who were current or previous, as in the past 5 years, coffee-drinkers who had persistent AF or atrial flutter with a history of AF. All patients were planned for electrical cardioversion across 5 hospitals in the U.S., Canada and Australia between November 2021 and December 2024. Final follow-up took place in June 2025. The participants were 1:1 randomized to continue regular coffee consumption (n=100) or caffeine abstinence (i.e. no coffee) (n=100) for 6 months. Patients who drank coffee were told to drink at least 1 cup of coffee per day. Patients who were to abstain from caffeine were told not to have any caffeinated products for the next 6 months. The baseline coffee consumption was 7 cups per week in both groups. Throughout the follow-up, participants in the caffeine consumption group had an average of 7 drinks per week and participants in the abstinence group had an average of 0 cups per week. Rates of AF or atrial flutter were significantly lower in the patients who regularly consumed coffee (47%) than patients who abstained from caffeine (64%) (hazard ratio [HR]=0.61, 95% confidence interval [CI]=0.42-0.89, p=0.01). No significant differences were observed in adverse events. Limitations were present in this study, Dr. Wong noted during his presentation, including the fact that only a minority of patients actually participated in the study, multiple methods were used to measure AF and atrial flutter, the abstinence group only had 69% who didn’t drink any coffee, all data related to caffeine intake were self-reported and participants were not blinded, they knew they were consuming caffeine. Overall, this trial demonstrated that coffee drinkers who underwent successful cardioversion and drank an average of 1 cup of coffee per day had fewer instances of AF or atrial flutter compared with the participants who drank zero caffeine and avoided caffeinated products. Source: Wong CX, Cheung CC, Montenegro G, et al. Caffeinated coffee consumption or abstinence to reduce atrial fibrillation: The DECAF randomized clinical trial. JAMA. 2025 November 9. doi:10.1001/jama.2025.21056 Image Credit: chayathon2000 – stock.adobe.com