What is the mitral valve? The mitral valve is located between the left atrium and the left ventricle and is composed of two flaps. Normally the flaps are held tightly closed during left ventricular contraction (systole) by the chordae tendineae (small tendon "cords" that connect the flaps to the muscles of the heart). In Mitral Valve Prolapse, the flaps enlarge and stretch inward toward the left atrium, sometimes "snapping" during systole, and may allow some backflow of blood into the left atrium (regurgitation). What causes Mitral Valve Prolapse? The cause of Mitral Valve Prolapse is unknown, but is thought to be linked to heredity. Primary and secondary forms of Mitral Valve Prolapse are described below. Primary Mitral Valve Prolapse. Primary Mitral Valve Prolapse is distinguished by thickening of one or both valve flaps. Other effects are fibrosis (scarring) of the flap surface, thinning or lengthening of the chordae tendineae, and fibrin deposits on the flaps. The primary form of Mitral Valve Prolapse is seen frequently in people with Marfan's Syndrome or other inherited connective tissue diseases, but is most often seen in people with no other form of heart disease. Secondary Mitral Valve Prolapse. In secondary Mitral Valve Prolapse, the flaps are not thickened. The prolapse may be due to ischemic damage (caused by decreased blood flow as a result of coronary artery disease) to the papillary muscles attached to the chordae tendineae or to functional changes in the myocardium. Secondary Mitral Valve Prolapse may... 更多資訊
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