A long-standing warning that people with atrial fibrillation should avoid caffeine came under scrutiny after researchers reported that a daily cup of caffeinated coffee cut the odds of a recurrent episode by nearly 40 percent. The data, released at the American Heart Association conference and published in JAMA, emerged from the DECAF randomized clinical trial, formally titled Does Eliminating Coffee Avoid Fibrillation.
The National Institutes of Health funded DECAF, which followed 200 habitual coffee drinkers, average age 69, at five hospitals in the United States, Canada, and Australia from November 2021 to December 2024. All volunteers had persistent atrial fibrillation or atrial flutter and were already scheduled for electrical cardioversion. Investigators randomly assigned participants either to drink at least one cup of caffeinated coffee daily or to abstain from all caffeinated products for six months. The coffee group averaged seven cups per week, while the abstinence group consumed none.
Electronic health records, electrocardiograms, wearable monitors, and implanted devices tracked recurrences. By six months, 47 percent of coffee drinkers and 64 percent of abstainers experienced another episode, a 39 percent relative-risk reduction for the coffee group. Coffee drinkers also went longer before their first recurrence.
“Doctors have always recommended that patients with problematic A-Fib minimize their coffee intake, but this trial suggests that coffee is not only safe but likely to be protective,” said principal investigator Dr. Christopher Wong. “Caffeine has a diuretic effect, which can lower blood pressure and consequently reduce the risk of atrial fibrillation,” said co-author Gregory Marcus, the endowed professor in Atrial Fibrillation Research at UCSF Health, according to Sabq. Marcus added that coffee’s natural anti-inflammatory compounds “may play a positive role in protecting the heart muscle from electrical irritation.”
Many participants had believed caffeine could trigger their arrhythmia, yet baseline surveys showed most had never experienced such a link. “It is very common for me to encounter patients who have stopped drinking caffeinated coffee only because their physician told them to do so,” said Marcus, according to NBC News. Cardiologist Johanna Contreras, who was not involved in the study, cautioned that “moderation is key,” noting that combining several cups with energy drinks would be different, NBC News reported.
About one-third of participants admitted at least one dietary lapse, and the trial did not assess other caffeinated beverages, limitations the authors acknowledged. The team plans to examine whether similar effects appear in ventricular tachycardia or chronic heart failure.
The preparation of this article relied on a news-analysis system.