Sleep apnea is a common and often undiagnosed disorder associated with substantial cardiovascular morbidity and mortality. In recent years studies have been published presenting the relationship between heart failure (HF) and central sleep apnea (CSA). CSA associated with Cheyne-Stokes respiration is a form of periodic breathing in which central apneas and hypopnea alternate with periods of hyperventilation, characterized by a regular crescendo-decrescendo oscillation of tidal volume, which is thought to be caused by dysfunction of central respiratory control. Unlike, obstructive sleep apnea (OSA), CSA likely arises as a consequence of HF.Since 2002, several results have reported on the benefit of atrial overdrive (AOP) pacing in patients suffering from sleep apnea. These results could not be confirmed for obstructive sleep apnea in several subsequent studies. Cardiac resynchronization therapy (CRT) has been proposed as another potential therapeutic pacing approach for CSA by two recently published investigations.The combined therapeutic impact of AOP and CRT (CRT+AOP) so far has not been investigated.We aimed to evaluate the effect of CRT alone and CRT+AOP on CSA in patients with CHF.