In Adults Treated for an Irregular Heartbeat, Drinking Coffee Beat Avoiding It

CATEGORY: FOODS & NUTRIENTS

Adults whose atrial fibrillation—an irregular, often racing heartbeat—had just been reset to normal rhythm were randomly assigned either to keep drinking coffee or to give up caffeine entirely, and after six months the coffee drinkers had done better: the irregular rhythm returned in 47% of them versus 64% of the abstainers, a 39% lower risk.¹ The trial, named DECAF and published in JAMA, is the first randomized test of coffee in people with this common heart-rhythm condition.

The Advice Every Heart-Rhythm Patient Hears

The study’s authors framed the question bluntly: conventional wisdom holds that caffeinated coffee provokes heart-rhythm disturbances, and people diagnosed with atrial fibrillation have long been advised to cut back or quit. Yet that advice had never been put through a randomized trial in these patients. DECAF was designed to test it directly—and the result ran opposite to the assumption it examined. Rather than triggering more episodes, a daily coffee habit went along with fewer of them, and the difference was statistically solid.¹

One Cup a Day or None at All for Six Months

Cardiologists at five hospitals in the United States, Canada, and Australia enrolled 200 adults—average age 69, about seven in ten men—who drank coffee currently or had within the past five years, and whose persistent atrial fibrillation was scheduled for electrical cardioversion, a brief, controlled electrical pulse delivered under sedation that resets the heart to a normal beat, something like rebooting a stuttering computer. Half were assigned to drink at least one cup of caffeinated coffee a day; the other half were asked to avoid coffee and all caffeine completely. The groups separated as intended—coffee drinkers averaged about seven cups a week, abstainers essentially none—and for six months doctors tracked whose atrial fibrillation or its close cousin, atrial flutter, returned in clinical follow-up.¹

47% Versus 64%, and No Extra Trouble

By the end of six months, the rhythm problem had come back in 47 of every 100 coffee drinkers and 64 of every 100 abstainers.¹ The result was essentially the same when the researchers counted only atrial fibrillation, leaving flutter aside. Safety told the same story: emergency-room visits (13 versus 16) and hospitalizations (23 versus 21) were similar between the groups, and no one in either group died. For a beverage patients are routinely told to fear, the trial recorded no signal that a daily cup was doing rhythm-related harm—and a consistent signal that it went with fewer relapses.

Swiss Records Lean the Same Way

The finding lands on top of observational research pointing in the same direction. In two Swiss studies that followed 3,835 people already living with atrial fibrillation for a median of 4.7 years, those who drank coffee daily had a 23% lower rate of major cardiovascular events—stroke, heart attack, heart-failure hospitalization, or cardiovascular death—than those who did not drink it daily, with the lowest rates among people drinking two to three cups a day.² Those studies observed people’s own habits rather than assigning them, so they show association rather than cause—but they found no evidence that daily coffee was linked to worse outcomes in this population, which is the same reassurance DECAF now delivers with a randomized design.

What Six Months and 200 People Can Say

The trial has honest boundaries. It enrolled 200 people and ran six months, so it speaks to relapse over that window, not to decades of heart health. Participants knew which group they were in, since a cup of coffee cannot be disguised, and everyone enrolled was already a coffee drinker or recently had been—so the trial says little about whether someone who has never liked coffee would gain anything by starting. The coffee group averaged about one cup a day, leaving open how heavier consumption would compare. What the trial does establish is narrow but useful: among coffee-drinking adults treated for this condition, giving up coffee did not protect their rhythm, and keeping the daily cup was the arm of the trial with fewer relapses.

Key Takeaways

• In the first randomized trial of coffee in atrial fibrillation, patients assigned to drink a daily cup after a rhythm-resetting procedure had a 39% lower risk of the irregular rhythm returning over six months—47 relapses per 100 people versus 64 per 100 among those told to avoid all caffeine.
• Emergency visits and hospitalizations were similar in both groups, and no deaths occurred in either.
• Observational data from 3,835 atrial fibrillation patients followed for nearly five years point the same way, linking daily coffee to fewer major heart events—an association, not proof of cause.
• The trial covered coffee drinkers averaging about one cup a day for six months; it does not address heavier intake, lifelong abstainers, or longer-term outcomes.

References

1. Wong CX, Cheung CC, Montenegro G, et al. Caffeinated Coffee Consumption or Abstinence to Reduce Atrial Fibrillation: The DECAF Randomized Clinical Trial. JAMA. 2026;335(4):317–325. link
2. Iten V, Herber E, Coslovsky M, et al. Coffee consumption and adverse cardiovascular events in patients with atrial fibrillation. BMC Medicine. 2024;22(1):593. link