Mitral valve prolapse is a disorder in which, during the contraction phase of the heart, the mitral valve does not close properly. When the valve does not close properly it allows blood to backflow into the left atrium. Some symptoms can include palpitations, chest pain, difficulty breathing after exertion, fatigue, cough, and shortness of breath while lying down.
Update Date 5/13/2014
Updated by: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.