Adults with atrial fibrillation who consumed one cup of caffeinated coffee daily demonstrated a 39% reduced likelihood of experiencing recurrent irregular heart rhythm episodes compared to those who avoided all caffeine, according to new research from the Does Eliminating Coffee Avoid Fibrillation (DECAF) trial presented at the American Heart Association's Scientific Sessions 2025. The study enrolled 200 adults diagnosed with AFib who typically consumed about one cup of coffee daily and were undergoing treatment to restore normal heart rhythm. Participants were randomly assigned to either continue drinking at least one cup of coffee daily or avoid all caffeine for six months following their cardioversion therapy.
During the study period, 47% of coffee drinkers experienced recurrent AFib or atrial flutter episodes lasting more than 30 seconds, compared to 64% in the no-caffeine group. "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. The research was simultaneously published in the peer-reviewed journal JAMA and presented at the American Heart Association meeting, with additional details available through the American Heart Association's Scientific Sessions 2025 Online Program Planner.
Study lead author Christopher X. Wong, M.B.B.S., M.Sc., M.P.H., Ph.D., noted that the trial specifically assessed whether caffeinated coffee increased or decreased AFib risk in regular coffee drinkers. All participants were followed for up to six months, with recurrent episodes verified by healthcare professionals or medical-grade electrocardiogram devices and recorded in medical records. The implications are significant for the more than 6 million Americans living with AFib, a condition that can lead to blood clots, stroke, heart failure and other cardiovascular complications according to the American Heart Association's 2025 Heart Disease and Stroke Statistics.
Researchers caution that the findings apply specifically to people who already drink about one cup of coffee daily and may not extend to those consuming higher amounts of caffeine or energy drinks. "It is reasonable for health care professionals to let their AFib patients consider experimenting with naturally caffeinated substances that they may enjoy, such as caffeinated tea and coffee," Marcus said, while acknowledging that some individuals might still experience AFib symptoms triggered by caffeine. The study was conducted at five healthcare centers in the United States, Australia and Canada with participants enrolled between 2021 and 2024, providing robust international data on caffeine's effects in this patient population.
