Periodic breathing is an abnormal pattern of breathing characterized by oscillation of ventilation between hyperpnea and hypopnea (not hyperpnea and Apnea as in Cheyne-Stokes respiration) with a crescendo-decrescendo pattern in the depth of respirations, to compensate for changing serum partial pressures of oxygen and carbon dioxide.[1]
Cheyne-Stokes respiration and periodic breathing are known together as Central sleep apnoea syndrome (CSAS)[1].