In patients with persistent AF who underwent cardioversion, a cup of joe per day lowered the risk of recurrences at 6 months.
NEW ORLEANS, LA—In good news for coffee drinkers with atrial fibrillation (AF)—maintaining the habit instead of giving it up is associated with less AF recurrence or atrial flutter, according to results of the DECAF randomized trial.
Among patients who underwent electrical cardioversion for sustained AF, drinking a cup of regular coffee daily, on average, was associated with a nearly 40% relative reduction in the risk of recurrence or atrial flutter over 6 months when compared with abstinence.
The study, which was presented during a late-breaking science session at the American Heart Association 2025 Scientific Sessions, challenges conventional wisdom that caffeine can lead to AF and other arrhythmias, say researchers.
“Coffee is one of the most commonly consumed beverages in our society and frequently has been considered to be proarrhythmic,” senior investigator Gregory Marcus, MD (University of California, San Francisco), said during a media briefing. “It is commonly nominated by patients to be a trigger for their AF episodes, and we as physicians continue to advise that either reduction or even abstinence may be helpful in this regard.”
José Joglar, MD (UT Southwestern Medical Center, Dallas, TX), who wasn’t involved in the study, said the vast majority of patients give up coffee, or cut back, once diagnosed with AF despite there being no evidence linking coffee to recurrent episodes.
“The fact is that this is a little bit of internet lore, but it keeps being replicated as patients Google information once diagnosed by physicians,” said Joglar. “They are also, to be fair, being advised to stop drinking coffee by their physicians.”
The 2023 guidelines for the diagnosis and management of AF, which were helmed by Joglar and Mina Chung, MD (Cleveland Clinic, OH), state there is no evidence supporting caffeine abstinence to reduce AF episodes but do say that it might help patients who report caffeine triggers. The guideline writers, however, acknowledge that the evidence in this area is mainly from observational studies.
Many Screened, but a Minority Participated
DECAF, which was published simultaneously in JAMA, included 200 patients (mean age 69 years; 71% male) with sustained AF (or atrial flutter with a history of AF) who were undergoing a planned electrical cardioversion and who had a history of drinking at least one cup of coffee per day in the past 5 years. Patients who weren’t currently drinking coffee but who met the inclusion criteria were eligible.
“We deliberately did not include only those who were consuming coffee when they were enrolled,” said Marcus. “I know from my clinical experience that many patients with atrial fibrillation have stopped drinking their caffeinated coffee because some physician had told them to do so. We wanted to make sure to include them.”
In total, 1,965 patients were screened, with 25% unwilling to abstain from coffee and 25% unwilling to drink one cup or more per day or to start drinking coffee again. Among the 200 randomized patients, AF symptom score, medication use, and history of a prior AF ablation were similar in both groups.
The type and frequency of clinical follow-up and investigations were left to the discretion of treating physicians and included ECGs, wearable ECG monitors, and/or implantable cardiac devices, in addition to health records.
The fact is that this is a little bit of internet lore, but it keeps being replicated as patients Google information. José Joglar
Christopher X. Wong, MBBS, PhD (University of California/University of Adelaide and Royal Adelaide Hospital, Australia), who presented the results during the late-breaking science session, said baseline coffee intake was a median of 7 cups per week. Following randomization, those assigned to coffee continued to drink a median of 7 cups per week while the majority of those assigned to abstinence stayed away from it.
By 180 days, those in the coffee arm had a 39% lower probability of recurrent AF or flutter compared with the abstinence group (HR 0.61; 95% CI 0.42-0.89). The results were similar when the analysis was restricted to “any coffee” consumption versus complete abstinence and consistent across most subgroups.
During the discussion, Wong acknowledged several limitations, chief among them that only a minority of patients screened were willing to undergo randomization.
“While many did not wish to abstain from coffee for the 6-month duration, many believed that coffee indeed precipitated the AF and declined to participate,” said Wong. “If coffee does cause AF in some individuals, this subpopulation may be underrepresented in our trial.”
Underlying Mechanisms
In the press conference, Marcus said DECAF is unable to determine if the same benefits would be observed with other caffeinated drinks, such as tea or cola. However, there are several known effects of caffeine that may protect against AF. In animal models, caffeine has been shown to prolong electrical recovery of cardiomyocytes in the atria. Caffeine also blocks adenosine receptors, which may prevent AF onset.
Data from their CRAVE study, added Marcus, also found that when people were randomly assigned to caffeine, they were more physically active. “We know this from their Fitbit data, and there’s now strong evidence that physical activity can reduce risks for atrial fibrillation,” he said.
Finally, caffeine, contrary to conventional wisdom, may lower blood pressure and also exert anti-inflammatory effects.
To the media, Joglar emphasized that the study applies to AF patients who stayed within the recommended daily dosage, which is less than 400 mg of caffeine per day, or no more than 3 to 4 cups per day.
“This does not apply to excess coffee consumption or energy drinks for that matter,” he said.
Andrea Russo, MD (Cooper University Health Care, Moorestown, NJ), said the DECAF trial provides much needed prospective data, but added that she’d like to see larger studies done in the future. Doing so would allow investigators to look at different caffeine dosages, as well as other sources of caffeine, to assess a dose-response relationship. Also, the study focused on patients with persistent AF undergoing cardioversion, so it’s unknown if coffee is also beneficial in those with paroxysmal AF, she said.
