Caffeinated coffee consumption was associated with a lower recurrence of atrial fibrillation or atrial flutter after cardioversion, according to the DECAF (Does Eliminating Coffee Avoid Fibrillation?) randomized clinical trial published in JAMA and presented at the 2025 American Heart Association Scientific Sessions.
The trial, led by Christopher X. Wong, MBBS, MPH, PhD, and Gregory M. Marcus, MD, MAS, of the University of California, San Francisco, is the first randomized study to directly examine the effect of caffeinated coffee on AF recurrence.
Among 200 adults (mean age, 69 years; 71% male) with persistent atrial fibrillation (AF) or atrial flutter and a history of AF, recurrence occurred in 47% of those who drank at least 1 cup of caffeinated coffee daily compared with 64% of those who abstained entirely from caffeine for 6 months. This corresponded to a 39% lower risk of recurrence among coffee drinkers. Rates of hospitalization, myocardial infarction, heart failure, stroke, and death were similar between groups.
Participants were recruited between November 2021 and December 2024 from 5 tertiary hospitals in the United States, Canada, and Australia. All underwent successful electrical cardioversion and were current or former coffee drinkers. Following randomization, participants were assigned either to consume caffeinated coffee daily or to abstain completely from all caffeine sources. Follow-up occurred at 1, 3, and 6 months through phone, video, or in-person visits. Continuous rhythm monitoring was used in more than half of participants with wearable or implantable ECG devices to document AF recurrence.
Average intake among coffee drinkers was seven cups per week, consistent with moderate habitual consumption. The investigators proposed that caffeine’s blockade of adenosine receptors and potential anti-inflammatory effects may contribute to reduced arrhythmogenic activity.
“Indeed, coffee is the most commonly consumed caffeinated substance in the US,” wrote the investigators. “However, despite its widespread use, whether coffee has a beneficial, detrimental, or neutral effect on AF continues to be debated.”
Several limitations were noted in the study, including the modest sample size, open-label design, and variable monitoring methods. Adherence to caffeine abstinence was incomplete, and participants’ awareness of group assignment could have influenced behavior. While half of the participants used continuous ECG monitoring, detection methods were not standardized, and those in the coffee group more often used wearable devices, which may have affected recurrence detection. The investigators noted that findings apply only to moderate, naturally occurring caffeine intake from coffee, not to high-dose or synthetic sources such as energy drinks. They also added that although results were statistically significant, larger blinded trials are needed to confirm whether moderate coffee consumption offers a protective effect against AF recurrence after cardioversion.
The study was supported by grants from Australian and US research organizations. Full author disclosures can be found in the published study.
Source: JAMA
