Mitral valve prolapse, the heart condition that felled 35-year-old Chad Schieber during the October 7 Chicago Marathon, generally isn't deadly. And it's fairly common—2 to 3 percent of the population has the condition, in which one or both flaps of the valve between the heart's two left chambers bulge backward, sometimes leaking blood in the wrong direction.
The Chicago medical examiner's office determined that Schieber's mitral valve was responsible for the death of the 12-year police officer, who was in excellent physical condition and had prepared thoroughly for the 26.2-mile run.
There's no way to know the seriousness of Schieber's disorder or whether he may have had other cardiovascular problems that hadn't been detected. A relatively tiny fraction of those with mitral valve prolapse are known to die suddenly of heart arrhythmias. They tend to be young, like Schieber. Some have no symptoms; others have a history of erratic heartbeat, chest pain, fainting, or other indicators.
Usually, however, mitral valve prolapse is a benign condition that doesn't interfere with physical activity, even an event as arduous as a marathon if an individual is in good shape and has trained adequately. "Physical stress, heat, fluid intake, electrolyte balance—individuals with MVP are not likely to be more affected by these factors than people without a mitral valve problem are," says Douglas Zipes, director emeritus of cardiology at the Indiana University School of Medicine (and born with mitral valve prolapse himself). He suspects that an undiagnosed condition—coronary artery disease, perhaps—contributed to the runner's death.
You can watch a video of a robotic mitral valve repair, with commentary from Dr. Bernadine Healy. In a column, Dr. Healy discussed the importance of repairing rather than replacing leaky mitral valves. Information about serious mitral valve defects is available from the Society for Mitral Valve Prolapse Syndrome, a patient resource group.