Sleep disordered breathing (SDB), in particular obstructive sleep apnea (OSA) and central sleep apnea-Cheyne-Stokes respiration (CSA-CSR), are prevalent in patients with heart failure and are associated with poor outcome.1 OSA is characterized by repeated pharyngeal airway collapse during sleep despite ongoing respiratory effort. CSA-CSR (or periodic breathing) describes a distinct respiratory pattern characterized by crescendo-decrescendo changes in tidal volume alternating with central apneas or central hypopneas. In both disorders, repetitive cortical arousals and oxyhemoglobin desaturation are of consequence during sleep. CSA-CSR in heart failure is thought to be secondary to instability of the ventilatory system due to increased chemo-responsiveness to Paco2. OSA in heart failure is thought to be due to a narrow upper airway, obesity, possibly pharyngeal wall edema, and ventilatory control instability.