Research has linked obesity to electrical abnormalities in heart rhythm, the most common such disorder in the world.
The study authors said it was known that obesity causes an increase in blood pressure, resulting in a strain on the heart, but a growing body of evidence showed it could also alter the structure and size of heart muscles.
Hospital admissions for atrial fibrillation have tripled in the past 15 years, with the condition, also linked with strokes and heart attacks puts overweight older men at risk.
Early results of the research show that if people lose weight, atrial fibrillation can be reversed.
Read more at University of Adelaide