If you live with atrial fibrillation and have been told to give up your morning coffee, this new research might make you look at your mug a little differently.
A randomized clinical trial of 200 adults with atrial fibrillation or a related rhythm problem found that those assigned to drink at least one cup of caffeinated coffee a day had fewer recurrent episodes than those told to avoid all caffeine.
Over six months, 47% of coffee drinkers had a recurrence compared with 64% in the no-caffeine group, which works out to about a 39% lower risk for the coffee group.
Why this matters for millions of hearts
Atrial fibrillation, often shortened to AFib, is one of the most common heart rhythm disorders. It affects more than 10 million adults in the United States and is linked to blood clots, stroke, heart failure, and trips to the emergency room when the heartbeat suddenly feels like a fish flopping in the chest.
For years, many doctors advised people with AFib to cut back on caffeinated coffee because caffeine can speed up heart rate. That advice has led plenty of patients to quietly mourn their morning brew while sipping decaf or herbal tea instead.
The new DECAF trial suggests that, at least for habitual coffee drinkers, the story is not so simple.
Inside the DECAF trial
Researchers from University of California San Francisco and the University of Adelaide designed the DECAF study to directly test caffeinated coffee in people who already had AFib. It is the first randomized clinical trial to do so, according to both the team and the journal that published the results.
The trial enrolled 200 adults who were current or recent coffee drinkers and had persistent AFib or atrial flutter. All were scheduled for cardioversion, a procedure that uses a controlled electric shock or medication to reset the heart to a normal rhythm.
After that procedure, participants were randomly assigned either to drink at least one cup of caffeinated coffee or an espresso shot every day, or to avoid all coffee and other sources of caffeine for six months.
Heart rhythm recurrences were tracked using medical records, electrocardiograms, and in many cases wearable or implanted devices.
When researchers looked at the results, they found fewer recurrences in the coffee group and a similar benefit when they focused only on AFib, not flutter. There was no clear increase in serious side effects among coffee drinkers.
How could coffee help, instead of hurt
So what might be happening inside that daily cup. Senior author Gregory M. Marcus told NBC News that the findings show “just how protective caffeinated coffee may be in preventing atrial fibrillation.”
In a separate statement from UC San Francisco, he explained that “coffee increases physical activity which is known to reduce atrial fibrillation” and noted that caffeine acts as a mild diuretic, which can lower blood pressure. Other components in coffee, such as antioxidant and anti-inflammatory compounds, may also play a role.
First author Christopher X. Wong went even further, saying “the results were astounding” and that the trial suggests coffee is “not only safe but likely to be protective” for many patients with problematic AFib.
Important limits and what patients should do
As reassuring as this sounds for coffee fans, the picture is not perfectly tidy. The study was open label, which means people knew which group they were in, and coffee intake was self reported. Many participants were already taking rhythm medications, and roughly half of those assigned to coffee still had an episode during the six months.
Cardiologist Johanna Contreras at Mount Sinai Fuster Heart Hospital in New York, who was not part of the research, told NBC that her takeaway was more cautious.
Moderate coffee “is fine for people with atrial fibrillation,” she said, but she stopped short of calling the drink truly protective. “This shows you can have a cup of coffee in the morning and be OK if you have A fib.”
In practical terms, that means most people with AFib who already enjoy a small daily coffee may not need to give it up automatically. It does not mean loading up on energy drinks or ignoring other triggers such as poor sleep, heavy alcohol use, or uncontrolled high blood pressure.
Decisions about caffeine should still be made with a cardiologist who knows the person’s full medical picture and understands how your choices fit into a healthcare system where even a short visit or a trip to the emergency room can quickly become expensive.
The study was published in JAMA Network.
