A Gasping Heart

Cardiac quirk may worsen sleep apnea, invite altitude sickness

A common imperfection in the structure of the heart may worsen breathing difficulties in people who have sleep apnea and provoke a life-threatening condition called high-altitude pulmonary edema in mountaineers who ascend too quickly. In both scenarios, new studies suggest, the cardiac abnormality contributes to a rapid drop in the blood’s oxygen content.