Floppy mitral valve/mitral valve prolapse/mitral valvular regurgitation: effects on the circulation.
The floppy mitral valve prolapses into the left atrium in such a dynamic manner that the prolapsing floppy mitral valve becomes a space-occupying lesion within the left atrium. A significant result of the floppy mitral valve prolapsing into the left atrium during left ventricular systole is the development of a "third chamber" located between the mitral annulus and the prolapsing mitral valve leaflets. Since the blood in the third chamber does not contribute to forward stroke volume, the third chamber may have significant effects on stroke volume and cardiac output. The floppy mitral valve/mitral valve prolapse dynamics also affect left ventricular papillary muscle tension and traction, altering the patterns of left ventricular contraction and relaxation, activating papillary muscle and left ventricular stretch receptors, and contributing to the production of cardiac arrhythmias. Floppy mitral valve innervation patterns with distinct nerve terminals provide a neural basis for brain-heart interactions, augmented by mechanical stimuli from the prolapsing floppy mitral valve. With the onset of mitral valvular regurgitation, and gradual progression of the mitral valve regurgitation from mild, to moderate, to severe, alterations in left atrial and left ventricular chamber size and performance occur, resulting in left atrial and left ventricular myopathy. As a connective tissue disorder, floppy mitral valve/mitral valve prolapse may be associated with abnormal structural and elastic properties of the aorta, with resultant changes in aortic function. Progression of mitral valve regurgitation and the aging process also affect aortic function indices in an adverse manner. The phenomena associated with floppy mitral valve dysfunction, with prolapse of the mitral valve into the left atrium and the unique, resultant forms of mitral valve regurgitation, are dynamic in nature. As the long-term natural history of these interrelated phenomena is being clarified, it is apparent that the floppy mitral valve/mitral valve prolapse/mitral valve regurgitation influences the circulation in a global fashion.
Boudoulas
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Division of Cardiology, Heart and Lung Research Institute, Ohio State University, 473 West 12th Avenue 2nd Floor, Columbus, OH 43210, USA.
Wooley
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D001011:Aorta / Q000502:physiology; D003326:Coronary Circulation; D004452:Echocardiography; D006325:Heart Atria; D006801:Humans; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008945:Mitral Valve Prolapse / Q000000981:diagnostic imaging / Q000503:physiopathology*; D009200:Myocardial Contraction; D010210:Papillary Muscles / Q000502:physiology; D016277:Ventricular Function, Left