A Gasping Heart
Cardiac quirk may worsen sleep apnea, invite altitude sickness
By Ben Harder
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.
In newborn babies, the wall of tissue that separates the left and right sides of the heart has a small opening called the foramen ovale. Usually, flaps of tissue that surround the hole fuse soon after birth, sealing the opening. In about a quarter of people, however, the flaps remain unsecured—and the opening stays “patent”—into adulthood.