Drinking coffee can protect against atrial fibrillation

Drinking coffee can protect against atrial fibrillation (A-Fib), a common heart rhythm disorder that causes rapid, irregular heartbeat and can lead to stroke and heart failure.

Doctors typically recommend that people with heart issues like A-Fib avoid caffeine out of fear that it will trigger symptoms. But a study by UC San Francisco and the University of Adelaid has concluded that drinking a cup of caffeinated coffee a day reduced A-Fib by 39%.

"Coffee increases physical activity which is known to reduce atrial fibrillation," said Gregory M. Marcus, MD, MAS, who holds the Endowed Professorship in Atrial Fibrillation Research and is an electrophysiologist at UCSF Health. Marcus is the senior author of the paper, which appears Nov. 9 in JAMA. "Caffeine is also a diuretic, which could potentially reduce blood pressure and in turn lessen A-Fib risk. Several other ingredients in coffee also have anti-inflammatory properties that could have positive effects."

A-Fib has been increasing in recent years along with obesity and the aging population. A-Fib, which has been diagnosed in more than 10 million U.S. adults, is estimated to affect up to 1 in 3 people.

Researchers named their study DECAF for Does Eliminating Coffee Avoid Fibrillation? It is the first randomized clinical trial to investigate the link between caffeinated coffee and A-Fib, and it was funded by the National Institutes of Health.

The study enrolled 200 coffee-drinking patients with persistent atrial fibrillation, or a related condition called atrial flutter along with a history of A-Fib. They were scheduled for electrical cardioversion, which gives a single electrical shock to shift the heart into a normal rhythm. They were randomly assigned either to consume at least one cup of caffeinated coffee or an espresso shot each day - or abstain from coffee and other products that contain caffeine for six months.

The group that consumed coffee had a 39% lower risk of recurrent A-Fib episodes. In addition to its anti-inflammatory effects, researchers speculated that drinking coffee might also reduce the risk of A-Fib simply by making people consume fewer unhealthy beverages.

The results were astounding. 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."

Christopher X. Wong, PhD, first author of UCSF and the University of Adelaide and Royal Adelaide Hospital