Among more than 228,000 patients, drinking coffee cut the frequency of episodes of atrial fibrillation by 6 percent, a study found

For some people coffee may help prevent abnormal heartbeats, Australian researchers found.

Many doctors advise patients with arrhythmias to avoid caffeine. But, for most heart patients, coffee and tea are safe and may sometimes reduce the frequency of arrhythmias, the researchers said.

Although coffee increases your heart rate, it does not make it abnormal," explained to Healthday.com senior researcher Dr. Peter Kistler. He is director of electrophysiology at Alfred Hospital and Baker Heart and Diabetes Institute in Melbourne.

"We found that there is no detrimental effects of coffee on heart rhythm and, in fact, coffee at up to three cups per day may be protective," he said.

Some people, however, may notice palpitations after drinking coffee, Kistler added, and those folks should avoid caffeine.

The Review

To see how caffeine affects patients with the common heart rhythm disorder known as atrial fibrillation, Kistler and colleagues looked at eight previously published studies.

Among more than 228,000 patients, drinking coffee cut the frequency of episodes of atrial fibrillation by 6 percent, the review found. A further analysis of nearly 116,000 patients found a 13 percent risk reduction.

One cup of coffee contains about 95 milligrams of caffeine and acts as a stimulant to the central nervous system. Caffeine also blocks adenosine, a chemical that can trigger atrial fibrillation, Kistler explained.

In addition, the researchers found that caffeine had no effect on abnormal heartbeats in the lower chambers of the heart, called ventricular arrhythmias.

As many as six cups of coffee a day, about 500 milligrams of caffeine, did not increase the severity or rate of ventricular arrhythmias, the study authors said.