Central alveolar hypoventilation (CAH) syndrome is a clinical condition that is characterized by the loss of automatic breathing, particularly during sleep. Most forms in adults are caused by brainstem ischemia, mass, infection, demyelinating disease, or anoxic-ischemic damage. We present a case of a fatal symptomatic acquired CAH syndrome caused by megadolichobasilar artery. A 62-year-old man with pre-existing vascular dementia suffered an acute posterior stroke. During stroke care, long episodes of hypopnea and apnea were observed which responded well to verbal reminders. During an unobserved episode, the patient was found unresponsive, with chemical signs of prolonged hypoventilation not explainable by cardiopulmonary disease. A diaphragmatic pacemaker, assisted ventilation, and repeated resuscitation were refused by the patient, who died some days later. CAH is a rare complication that can occur in patients with megadolichobasilar artery.