Adults treated for atrial fibrillation (AFib) who drank a daily cup of coffee were 39% less likely to experience a recurrence of irregular heart rhythm compared to those who avoided all caffeinated products, according to new research presented at the American Heart Association's Scientific Sessions 2025. The findings challenge the common belief that caffeine may trigger or worsen AFib.
The Does Eliminating Coffee Avoid Fibrillation (DECAF) trial enrolled 200 adults diagnosed with AFib who were about to undergo cardioversion therapy to restore a normal heart rhythm. Participants, who typically drank about one cup of caffeinated coffee per day, were randomly assigned to continue drinking at least one cup of coffee daily or to avoid all caffeine for six months after treatment. The study was conducted at five health care centers in the United States, Australia and Canada, with enrollment between 2021 and 2024.
During the six-month follow-up, 47% of participants in the coffee group had a recurrent AFib or atrial flutter episode lasting more than 30 seconds, compared to 64% in the no-caffeine group, representing a 39% lower risk. Similar reductions were observed when only AFib episodes were considered. The results were simultaneously published in the peer-reviewed journal JAMA.
“Our study results suggest that caffeinated coffee may not be responsible for raising the risk of AFib and may even reduce it,” said senior study author Gregory M. Marcus, M.D., M.A.S., a professor of medicine at the University of California, San Francisco, in a news release. However, Marcus noted that some individuals may still find that caffeine triggers or worsens their AFib symptoms, and it is reasonable for health care professionals to let patients experiment with naturally caffeinated beverages like tea and coffee if they enjoy them.
AFib currently affects more than 6 million people in the U.S. and can lead to blood clots, stroke, heart failure and other heart-related conditions, according to the American Heart Association’s 2025 Heart Disease and Stroke Statistics. The study enrolled only people who already drank coffee, so future research may investigate whether AFib episodes are reduced in individuals who start drinking coffee or other caffeinated beverages for the first time.
The trial’s lead author, Christopher X. Wong, M.B.B.S., M.Sc., M.P.H., Ph.D., formerly of the University of California, San Francisco, and currently professor of cardiology at the University of Adelaide in Australia, emphasized that the results may not apply to people who consume more than one cup of coffee daily or other caffeinated products like energy drinks. Participants in the coffee group maintained their pre-enrollment habit of about one cup per day, while the no-coffee group reported consuming no caffeine.
The study was funded by various sources, and co-authors, disclosures, and funding details are listed in the abstract available on the AHA’s Online Program Planner. The findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.
