Mitral Valve Prolapse
- Mitral Valve Prolapse (MVP) is a specific disease entity which causes loosening and floppiness of the heart valve leaflets, most seriously affecting those of the mitral valve. Although often asymptomatic, MVP can lead to the development of the general pathophysiological phenomenon of mitral regurgitation (Do not confuse these two terms).
- The Mitral Valves of those with MVP appear physically soft and floppy, resulting in their billowing into the left atrium during ventricular systole. This morphological pattern is also observed in the chordae tendineae which are often elongated, weak, and prone to rupture. Histologically, the tough fibrous central layer of the mitral valve, as well as other heart valves, and chordae tendineae are replaced with a loose, myxomatous material which has an inferior capacity to counteract physical stress.
- The myxomatous degeneration observed in MVP is likely the common morphological endpoint of multiple, distinct etiological processes. Consequently, MVP may be inherited as an isolated autosomal dominant disorder or may occur as a component of Marfan Syndrome, Ehlers-Danlos Syndrome, and other connective tissue diseases. It should be pointed out that MVP is a very common disorder with nearly 2-3% of the general population displaying some features of MVP given detailed echocardiographic screening.
- In most cases MVP is completely asymptomatic and is discovered incidentally due to auscultation of a characteristic "Mid-systolic Click" followed by a late systolic heart murmur. These auscultory findings reflect the sudden tension encountered by the loose, elongated chordae tendineae midway during systole as the mitral valve is forced into the left atrium, followed by the sounds of mild mitral regurgitation.
- In a small minority of patients important complications can arise. Occasionally, the loose chordae tendineae can rupture resulting in severe, acute mitral regurgitation, comprising a medical emergency. The Mitral Valve of those with MVP appears to be more prone to infective endocarditis. Finally, patients with MVP are prone to ventricular arrhythmias for cryptic reasons.