Drinking more than 10 alcoholic drinks a week (less than 2 a day) or four cups of strong coffee each day can increase the risk of developing an irregular heartbeat, new research suggests.

Two studies presented at the European Society of Cardiology congress in Barcelona found that alcohol and caffeine intake can affect the chances of developing an abnormal heart rhythm, known as atrial fibrillation.

About 46,000 people in Britain are diagnosed with atrial fibrillation every year. The condition greatly increases the risk of having a stroke, heart attack or other cardiac problems.

The study into alcohol, carried out on 8,830 men and women in Britain, Scandinavia and the United States, found that those who drank the equivalent of 10 standard drinks had an 80 percent increased risk of being diagnosed with the condition within five years.

The patients in the study had an average age of 67 and were already receiving treatment for high blood pressure but had no previous signs of atrial fibrillation. They were followed for an average of 4.8 years, during which time heart scans revealed atrial fibrillation in 5.7 percent of patients who reported drinking more than 10 drinks a week, compared to 3.9 percent of patients who drank less or no alcohol at all.

Inger Ariansen, who led the study at Oslo University Hospital, suggested that 10 drinks could be regarded as a threshold for increased risk of atrial fibrillation, although she pointed out that different countries defined the amount of alcohol contained in a typical drink differently.

The second study, by researchers at the University of Modena, found that drinking more than the equivalent of four espresso shots a day could increase the risk of arrhythmias in people without known heart disease, even if they otherwise had a healthy diet.

Click here to read more on this story from the Times of London.