One cup of coffee a day could keep atrial fibrillation from coming back

By Priyanjana Pramanik, MSc.Reviewed by Susha Cheriyedath, M.Sc.Nov 10 2025

In a first-of-its-kind randomized trial, patients who kept drinking coffee after cardioversion were less likely to experience recurrent atrial fibrillation, upending decades of caution against caffeine for heart rhythm disorders.

Study: Caffeinated Coffee Consumption or Abstinence to Reduce Atrial Fibrillation. Image Credit: Iryna Tsiareshka / Shutterstock

In a recent article published in the Journal of the American Medical Association on November 9, 2025, researchers examined the effect of coffee consumption on the recurrence of atrial fibrillation (AFib) in patients who had successfully undergone electrical cardioversion for persistent AF or atrial flutter with a history of AF.  

Their findings indicate that, contrary to prior assumptions, drinking coffee may be associated with a lower risk of AFib recurrence, with a hazard ratio of 0.61 (95% CI, 0.42 to 0.89; P = .01), and no increase in adverse events over a six-month observation period.

Global Burden and Mechanisms of Atrial Fibrillation

AFib is the most prevalent heart rhythm disorder affecting millions globally, with incidence expected to rise due to aging populations and improved detection. It is characterized by an irregular, often rapid heartbeat that can lead to heart failure and stroke. The condition originates in the atria, where disorganized electrical signals cause quivering rather than coordinated contractions.

Coffee as a Suspected Arrhythmia Trigger

Because of caffeine’s stimulant effects, coffee has long been considered a potential AFib trigger. Many clinicians advise patients to limit or avoid it, assuming it increases the risk of arrhythmias. However, this perception is being reevaluated as new data emerge.

Emerging Evidence on Coffee and Heart Rhythm

Recent trials have shown that coffee consumption does not increase premature atrial contractions, a known trigger of AFib. Several observational studies have even linked moderate coffee intake with a reduced risk of AFib. To provide causal evidence, researchers designed the Does Eliminating Coffee Avoid Fibrillation? (DECAF) randomized clinical trial to test whether continued coffee consumption versus abstinence affects AFib recurrence after cardioversion.

DECAF Trial Design and Methodology

The DECAF trial was conducted at five hospitals in Australia, Canada, and the United States, enrolling 200 adults aged 21 years or older with persistent AFib or atrial flutter and a history of AFib. After successful cardioversion, participants were randomized to either continue drinking at least one cup of caffeinated coffee daily or abstain entirely from coffee and other caffeine sources for a period of six months.

Follow-up visits occurred at one, three, and six months, either in person or remotely. Adherence, adverse events, and AFib recurrence were tracked, with many participants using wearable ECG monitors. The primary endpoint was the time to clinically confirmed recurrence of AFib or atrial flutter lasting 30 seconds or more.

Principal Findings and Statistical Outcomes

Baseline characteristics were balanced between groups, with a median intake of about one cup per day. At six months, AFib or atrial flutter recurrence occurred in 47% of coffee drinkers and 64% of abstainers. Caffeinated coffee consumption was linked to a 39% lower hazard of recurrence (HR 0.61; 95% CI 0.42 to 0.89; P = .01).

Secondary analyses showed similar trends for AFib alone and fewer flutter recurrences, though the latter was not statistically significant. Adverse events and hospitalizations were similar between groups, with no deaths reported.

Clinical Implications and Study Limitations

This randomized trial demonstrates that moderate intake of caffeinated coffee after cardioversion may reduce the recurrence of AFib or atrial flutter. The findings challenge long-held beliefs that coffee promotes arrhythmia and align with prior observational data suggesting neutral or beneficial effects.

Potential mechanisms include adenosine receptor blockade, anti-inflammatory effects, and possible promotion of physical activity. Strengths include its randomized design and consistent sensitivity results; however, limitations include a small sample size, lack of blinding, and self-reported adherence. These results should not be extrapolated to high-dose caffeine or energy drinks.