Mayo Clinic researchers looked at a 10-year experience of 1,200 patients who came to the Windland Smith Rice Genetic Heart Rhythm Clinic. The researchers found that 24 of those patients were survivors of out-of-hospital cardiac arrest. Ten of those 24 survivors — 42% — had bileaflet prolapse. That finding helped the research team identify the features of arrhythmogenic bileaflet mitral valve prolapse syndrome.