IN CONSULTATION including enlargement of the mitral leaflets and annulus and prominent leaflet thickening (5). For the majority of patients, MVP is a benign condition. However, a minority of patients with MVP develop severe mitral regurgitation, infective endocarditis, neurologic ischemia, or sudden death. MVP is the most common valvular etiology of severe mitral regurgitation in industrialized nations and, conversely, this is the most frequent complication of MVP (1, 6). The likelihood of a patient developing severe mitral regurgitation increases with age and is considerably greater in men than in women with MVP (6). In contrast to the female predominance among subjects with uncomplicated MVP, approximately two-thirds of patients with severe mitral regurgitation are men. By age 75, approximately 1.5 to 2.0% of women with MVP and 5.5% of affected men develop regurgitation of sufficient severity to require surgical valve repair or replacement. In addition to the irreversible risk factors of age and gender, there is some evidence that high blood pressure or body weight may promote progression of regurgitation due to MVP (6). Infective endocarditis occurs in about one-fourth as many patients with MVP as does severe regurgitation, implying a cumulative risk under 1% by age 75. The risk of endocarditis among these patients is about three-fold higher in men than in women, and in those with a mitral regurgitant murmur (7). As in mitral regurgitation, nearly 60% of patients with MVP who develop infective endocarditis are men. We found that in MVP patients, endocarditis causes a substantial cumulative increment in risk of death or failure to survive without mitral valve surgery, as well as the need for hospitalization and the incidence of heart failure (7). Neurologic ischemia appears to occur more commonly in individuals with MVP than in the general population, but the association is so weak that it can only be clearly identified in groups at low risk of stroke, such as young women. Sudden death is the most feared but least understood major complication of MVP. An increased, although small, risk of sudden death is well established in patients with MVP and mitral regurgitation, although this appears to be related to the severity of mitral regurgitation rather than to the causal role of MVP (8). Sudden death in MVP patients without known severe regurgitation is often associated with severe valvular deformity and with increased LV mass, suggesting that unrecognized regurgitation or some hemodynamic overload may have been present (8). The initial step in the management of most patients with MVP is reassurance that the condition is generally benign and may even be marginally beneficial if it has conferred the common tendency to low body weight and low blood pressure. For individuals with only a mid systolic click and no mitral regurgitant murmur on several physical examinations, as well as no evidence of mitral regurgitation on Doppler echocardiography, there is no clear evidence that PERSPECTIVE Mitral Valve Prolapse: Clinically Relevant Aspects Jonathan N. Bella, MD and Richard B. Devereux, MD, Division of Cardiology, Department of Medicine, The New York Hospital-Cornell Medical Center, New York, New York Mitral valve prolapse (MVP) is the most common valvular abnormality in industrialized nations, affecting 3 to 4% of adults (1, 2). Although MVP has been reported to have many causes, most instances occur as a primary condition. Studies of over 100 families performed at Cornell Medical Center in New York City have shown that primary MVP is passed from affected mothers and fathers to children of both genders, indicating an autosomal dominant inheritance pattern (1). Family studies have demonstrated that MVP has an age-ofonset between 10 and 16 years, is more consistently expressed in women than in men and may become undetectable after middle age in some mildly affected women (1). As a consequence of the gender difference in expression of primary MVP, nearly two-thirds of adults with this condition are women. These family studies have also documented extracardiac features of primary MVP, including a tendency for low body weight and low blood pressure, which might provide a genetic “selective advantage” that could account for the high prevalence of inherited MVP (3). In addition, thoracic bony abnormalities including pectus excavatum, mild scoliosis and a straight thoracic spine occur several times more commonly in adults with MVP than in members of the general population (3). MVP is usually first recognized by auscultation as a midsystolic click and a late-murmur, which are separated from the first heart sound by a silent interval, but which continue to reach or even pass slightly beyond the second heart sound. Maneuvers that reduce LV chamber size cause the click and onset of the murmur to move closer to the first heart sound (1, 4). Two-dimensional echocardiography has enhanced the recognition and assessment of the severity of MVP, which may be diagnosed accurately by two-dimensional echocardiography when one or both mitral leaflets protrude or “billow” into the left atrium in systole in the parasternal or apical long-axis view (1, 5). It is important not to diagnose MVP based upon apparent protrusion of the mitral leaflets into the left atrium in the apical four-chamber two-dimensional view, as this is a common artifact of the normal “saddle” shape of the mitral annulus (5). In addition, twodimensional echocardiography helps to identify mitral valve abnormalities associated with more severe forms of MVP ACC CURRENT JOURNAL REVIEW May/June 1998 © 1998 by the American College of Cardiology Published by Elsevier Science Inc. 80 1062-1458/98/$19.00 PII S1062-1458(98)00035-X IN CONSULTATION endocarditis prophylaxis is necessary (6). It is reasonable to reevaluate MVP patients with no evidence of regurgitation at 5-year intervals. The severity of mitral regurgitation provides the most sound guide to the need for active treatment and more frequent follow-up. For an individual with intermittent or persistent mild regurgitation or murmurs, there is a need for antibiotic prophylaxis (9), treatment of mild hypertension and clinical echocardiographic examination every 2 to 3 years. An individual with severe regurgitation requires antibiotic prophylaxis (9) and annual evaluation and testing with Doppler echocardiography and if necessary, Holter monitoring or stress testing. Surgical correction of severe mitral regurgitation is indicated when symptoms develop or when LV systolic function decreases to the lower part of the normal range. In a previous study, we found that echocardiographically derived LV fractional shortening of 31% is a useful lower limit of acceptable LV function (10). 3. Devereux RB, Brown WT, Lutas EM, Kramer-Fox R, Laragh JH. Association of mitral valve prolapse with low body weight and low blood pressure. Lancet 1982;2:792–5. 4. Devereux RB, Perloff JK, Reichek N, Josephson ME. Mitral valve prolapse. Circulation 1976;54:3–14. 5. Levine RA, Stathogianiis E, Newell JB, Harrigan P, Weyman AE. Reconsideration of echocardiographic standards for mitral valve prolapse: Lack of association between leaflet displacement isolated to the apical four-chamber view and independent echocardiographic evidence of abnormality. J Am Coll Cardiol 1988;11:1010 –9. 6. Zuppiroli A, Rinaldi M, Kramer-Fox R, Favilli S, Roman MJ, Devereux RB. Natural history of mitral valve prolapse. Am J Cardiol 1995;75:1028 – 32. 7. Frary CJ, Devereux RB, Kramer-Fox R, Roberts RB, Ruchlin HS. Clinical and health-care cost consequences of infective endocarditis in mitral valve prolapse. Am J Cardiol 1994;73:163–7. 8. Kligfield P, Hochreiter C, Niles N, Devereux RB, Borer JS. Relation of sudden death in pure mitral regurgitation with or without mitral valve prolapse to repetitive ventricular arrhythmias and right and left ventricular ejection fraction. Am J Cardiol 1987;60:397–9. 9. Dajani AS, Taubert KA, Wilson W, et al. Prevention of bacterial endocarditis. Recommendations by the American Heart Association. JAMA 1997;277:1794 –1801. 10. Furer J, Hochreiter C, Niles NW, et al. Prediction of symptom status following mitral valve replacement for mitral regurgitation by preoperative echocardiographic measurement of the end-systolic stress to end-systolic volume ratio. Am J Noninvasive Cardiol 1987;1:321– 8. REFERENCES 1. Devereux RB, Kramer-Fox R, Shear MK, Kligfield P, Pini R, Savage DD. Diagnosis and classification of severity of mitral valve prolapse: Methodologic, biologic and prognostic considerations. Am Heart J 1987;113: 1265– 80. 2. Levy D, Savage DD. Prevalence and clinical features of mitral valve prolapse. Am Heart J 1987;113:1281–90. Address correspondence and reprint requests to Richard B. Devereux, MD, Division of Cardiology, Box 222, The New York Hospital-Cornell Medical Center, 525 East 68th St., New York, NY 10021. ACC CURRENT JOURNAL REVIEW May/June 1998 81