To the Editor: I read with interest the article by Corra and associates1 that appeared in a recent Circulation issue. In 133 chronic heart failure patients, the authors elegantly demonstrated that those (n=22) who exhibit both central sleep apnea (CSA; apnea/hypopnea index ≥30) and exercise oscillatory ventilation (EOV) have a very unfavorable prognosis. The negative survival expectation is, however, primarily driven by CSA, a recognized prognostic marker, rather than by EOV, a disorder found to be prognostic irrespective …