Obesity, obstructive sleep apnea may disrupt heartbeat

Obesity and a common sleep problem called obstructive sleep apnea may raise the risk of atrial fibrillation, a rapid, irregular heartbeat that increases the risk of stroke, according to a report in the Journal of the American College of Cardiology.

Obstructive sleep apnea occurs when soft palate and other tissues in the back of the throat collapse during sleep, temporarily blocking airflow into the lungs. A patient with the disorder often experiences several brief episodes of absent breathing during a night of sleep. While the problem usually does not have life-threatening consequences, the disrupted sleep can lead to excessive sleepiness the following day and impinge on quality of life.

Dr. Virend K. Somers and colleagues from the Mayo Clinic College of Medicine, Rochester, Minnesota conducted a study of 3542 adults who were being evaluated for sleep disturbances. During an average follow-up period of 4.7 years, 133 subjects developed atrial fibrillation.

Along with other established risk factors for the irregular heartbeat, obesity strongly predicted the occurrence of atrial fibrillation, the investigators report, as did the severity of sleep apnea.

Among patients over 65 years of age, however, only heart failure predicted the development of atrial fibrillation.

"Our results have important implications, first, for understanding (how atrial fibrillation develops), and second, for the growing obesity epidemic, which is accompanied by a significant increase in the number of individuals with sleep apnea," the researchers conclude.

"Treatments targeting obesity are imperative," they add. Further studies are needed to determine if treating sleep apnea can prevent atrial fibrillation.

SOURCE: Journal of the American College of Cardiology, February 6, 2007.