Upto 3 cups coffee per day safe & even reduces frequency of arrhythmias

A single cup of coffee contains about 95 mg of caffeine and acts as a stimulant to the central nervous system. Once in the body, caffeine blocks the effects of adenosine, a chemical that can facilitate AFib.

The authors analyzed multiple population-based studies to determine an association between caffeine intake and its effects on atrial and ventricular arrhythmias. These studies have consistently shown a decrease in AFib with an increase in caffeine ingestion, with one meta-analysis of 228,465 participants showing AFib frequency decreasing by 6 percent in regular coffee drinkers, and a further analysis of 115,993 patients showing a 13 percent risk reduction.

"There is a public perception, often based on anecdotal experience, that caffeine is a common acute trigger for heart rhythm problems," said Peter Kistler, MBBS, PhD, director of electrophysiology at Alfred Hospital and Baker Heart and Diabetes Institute, and the review's lead author. "Our extensive review of the medical literature suggests this is not the case."

The authors also determined that caffeine has no effect on ventricular arrhythmias (VAs). Caffeine doses up to 500 mg daily (equivalent to six cups of coffee) did not increase the severity or rate of VAs. A randomized study of 103 post-heart attack patients who received an average of 353 mg/day resulted in improved heart rate and no significant arrhythmia. Only two studies showed an increased risk for VAs, where patients ingested at least 10 cups and nine cups/day, respectively.