Cheyne-Stokes respiration with central sleep apnea (CSA-CSR) is a disorder commonly seen in patients with heart failure and characterized by cyclic hyperventilation with hypocapnia, which distinguishes it from obstructive sleep apnea and disorders of hypoventilation. The response of CSA-CSR to therapies targeted at the failing heart is proportional to the improvement in cardiac function. The apnea-hypopnea index is a crude marker of CSA-CSR severity and consideration should always be given to collateral history and examination, plus markers of cardiac and sleep dysfunction, plus quality of life when deciding to monitor or manage.