NEW YORK (Reuters Health) – New research suggests that obesity not only increases the risk of first atrial fibrillation, it also increases the odds that paroxysmal atrial fibrillation will become permanent.

“This study extends our understanding of the relationship between obesity/left atrial size and atrial fibrillation. Specifically, there was a graded risk relationship between body mass index and progression from paroxysmal to permanent atrial fibrillation, and larger left atrial size augmented the risk of such progression,” Dr. Teresa S. M. Tsang and associates write.

The study, which is reported in the European Heart Journal for September, involved 3248 patients in Olmsted County, Minnesota, who were diagnosed with paroxysmal atrial fibrillation between 1980 and 2000, and were followed through 2006.

During a median of 5.1 years, 557 subjects (17%) progressed to permanent atrial fibrillation, Dr. Tsang, from the Mayo Clinic in Rochester, Minnesota, and colleagues report.

On multivariate analysis, BMI was an independent predictor of progression to permanent atrial fibrillation. Relative to normal BMI, obesity and severe obesity increased the odds of progression by 54% (p = 0.0004) and 87% (p < 0.0001), respectively. Echocardiographic assessment, which was performed in a subset of 744 patients, indicated that left atrial volume did not attenuate the association between BMI and progression to permanent atrial fibrillation. “Studies of weight reduction, and of reversal of left atrial enlargement, may provide insight as to whether these interventions may lower the risk for the development of first atrial fibrillation, and reduce or delay the progression from paroxysmal to permanent atrial fibrillation,” the research team suggests. Reference:
Eur Heart J 2008;29:2227-2233.