Atrial fibrillation, the LEGACY study, and obstructive sleep apnea

The LEGACY study found that weight loss improved both symptoms and cardiac arrhythmias in persons with atrial fibrillation.

Medscape discusses the findings of the LEGACY trial here:
http://www.medscape.com/viewarticle/841515  (for registered users of Medscape)

Here is a link to the article's abstract:
 http://content.onlinejacc.org/article.aspx?articleID=2196400

I wonder how much of the improvement in atrial fibrillation came from the treatment (by weight loss) of undiagnosed obstructive sleep apnea???

There is strong evidence for a relationship between OSA and atrial fibrillation.  Control of obstructive sleep apnea through CPAP treatment approximately doubles the success rate of rhythm control in persons with atrial fibrillation.