Even relatively low levels of drinking may trigger potentially dangerous irregular heatbeats, research has shown.

A review of data from more than 100 studies with almost 900,000 participants found that every extra alcoholic drink consumed per day increased the risk of atrial fibrillation (AF) by 8%.

AF occurs when the heart loses rhythm, so that it beats in a haphazard way. The condition can cause blood to pool and clot and is closely linked to strokes and heart failure.

Previous studies have suggested that light to moderate alcohol intake - up to seven standard drinks per week for women and 14 for men - can benefit health and reduce the risk of narrowed arteries.

But the good news does not apply to heartbeat, according to the new findings published in the Journal of the American College of Cardiology.

Lead researcher Professor Peter Kistler, from the Alfred Hospital in Melbourne, Australia, said: "There has been a lot of attention in recent years about the benefits of drinking small amounts of alcohol for the heart.

"The results are significant, since chances are, there are people who are consuming one to two glasses of alcohol per day that may not realize they are putting themselves at risk for irregular heartbeat."

Alcohol has many effects on the human body, several of which are likely contribute to irregular heartbeat, say the scientists.

Drinking alcohol can lead to small amounts of fibrous tissue within the heart, they point out. In addition, alcohol may alter electrical signals that regulate the contraction of heart muscle cells, and also affect the autonomic nervous system which controls many bodily functions.

The researchers advised people who experienced occasional irregular heart beats to limit their alcohol consumption to one drink a day, and ensure they have two "dry" days per week.

Christopher Allen, senior cardiac nurse at the British Heart Foundation, said: "The festive period is often a time of feasting and celebrations which can often lead to an increase in alcohol consumption.

"No one should increase their alcohol units or take up drinking alcohol based on any current or past research into the possible benefits. Any small benefits there could be from drinking alcohol are far outweighed by the risks and drinking too much could lead to irregular heart rhythms and also liver failure, high blood pressure and stroke."