GradedHealth

Can you drink coffee with atrial fibrillation? A 200-patient trial says yes

In a 200-person trial, people with atrial fibrillation who kept drinking about a cup of coffee a day had fewer relapses after cardioversion than those who quit.

Published October 2026

Short answer

Yes, for coffee drinkers after cardioversion: about a cup a day went with fewer AF relapses than quitting (47% vs 64%). Early evidence from one open-label trial of 200 people. Evidence grade C (Limited). One randomised open-label trial of 200 people, backed by observational meta-analyses; downgraded for small sample and open-label design.

Key takeaways

  • In the DECAF trial, 200 adults with persistent atrial fibrillation were assigned to keep drinking caffeinated coffee or to give up coffee and caffeine for six months [1].
  • AF or flutter came back in 47% of the coffee group and 64% of the abstinence group, a 39% lower chance of relapse at any point with coffee [1].
  • Large cohort analyses found no higher risk of developing AF in coffee drinkers; each extra cup a day went with a 2% lower risk [2].
  • A 14-day trial of 100 adults found no significant rise in premature atrial beats on coffee days, but more premature ventricular beats and 36 fewer minutes of sleep [3].
  • This is one open-label trial of about a cup a day in people about to have a cardioversion, so it cannot speak for heavy intake or other forms of AF [1].

What the study did

The DECAF trial enrolled 200 adults with persistent atrial fibrillation (AF), or atrial flutter with a history of AF, who were due to have an electrical cardioversion, a procedure that shocks the heart back into a normal rhythm. All of them drank coffee, or had in the previous five years, and they were recruited at five hospitals in the US, Canada and Australia [1]. The average age was 69 and 71% were men [1].

Half were assigned to keep drinking caffeinated coffee, with at least one cup a day encouraged. The other half were asked to avoid coffee, decaffeinated coffee and other caffeine products for six months [1]. The main outcome was a return of AF or flutter that doctors detected over those six months [1].

What it found

The two groups ended up far apart: the coffee group drank a median of 7 cups a week and the abstinence group a median of 0 [1]. AF or flutter came back in 47% of the coffee group and 64% of the abstinence group, which works out to a 39% lower chance of a relapse at any point with coffee (hazard ratio 0.61, 95% CI 0.42 to 0.89) [1]. The benefit looked similar when only AF was counted, and the groups did not differ significantly in side effects [1].

The authors note that conventional wisdom holds coffee to be proarrhythmic, and that no randomized trial had tested coffee in people with AF before [1].

How it fits

Observational research already pointed the same way for the risk of developing AF. A pooled analysis of 10 prospective studies (723,825 people, 30,169 AF cases) found no higher risk at 1 to 7 cups a day, and each extra cup a day went with a 2% lower risk [2]. An earlier pooled analysis of six cohorts (228,465 people) found a 6% lower risk for every extra 300 mg of caffeine a day [4]. Those studies ask who develops AF, not who relapses after cardioversion, and they cannot show cause and effect.

A randomized trial in which 446 people with intermittent AF tested their own suspected triggers found no sign that caffeine set off AF more often; alcohol was the one trigger linked to more AF events [5].

The heart-rhythm picture is not entirely one-sided. In a 14-day randomized trial of 100 adults (average age 39), caffeinated coffee days brought no significant rise in premature atrial beats (58 against 53 a day), but more premature ventricular beats (154 against 102 a day) and 36 fewer minutes of sleep a night [3]. A pooled analysis of human interventional studies found no significant effect of caffeine on premature ventricular beats overall [6].

Limits

  • The trial was open-label, so participants and doctors knew who was drinking coffee, and recurrences were those detected clinically [1].
  • It was small (200 people) and lasted six months [1].
  • It tested about one cup of coffee a day, not heavy intake, energy drinks or caffeine supplements [1].
  • Everyone already drank coffee, so it does not show that people who avoid coffee would gain by starting [1].
  • It enrolled people about to have a cardioversion for persistent AF, so it says little about other forms of AF [1].

Anyone with AF who is wondering about their own coffee habits should talk to their cardiologist. Our Coffee page has the full safety notes, including caffeine and medicines.

Go deeper

  • Coffee — Large observational studies link 3 to 4 cups of coffee a day with a lower risk of death, heart disease and type 2 diabetes, but they cannot prove cause.

References

  1. Caffeinated Coffee Consumption or Abstinence to Reduce Atrial Fibrillation: The DECAF Randomized Clinical Trial.. JAMA, 2026.
  2. Association of Coffee Consumption With Atrial Fibrillation Risk: An Updated Dose-Response Meta-Analysis of Prospective Studies.. Front Cardiovasc Med, 2022.
  3. Acute Effects of Coffee Consumption on Health among Ambulatory Adults.. N Engl J Med, 2023.
  4. Caffeine intake and atrial fibrillation incidence: dose response meta-analysis of prospective cohort studies.. Can J Cardiol, 2014.
  5. Individualized Studies of Triggers of Paroxysmal Atrial Fibrillation: The I-STOP-AFib Randomized Clinical Trial.. JAMA Cardiol, 2022.
  6. Effect of caffeine on ventricular arrhythmia: a systematic review and meta-analysis of experimental and clinical studies.. Europace, 2016.