ESSENTIALS OF DIAGNOSIS
Single or multiple mid-systolic clicks often heard on auscultation.
Murmur may be pansystolic or only late in systole.
Often associated with skeletal changes (straight back, pectus excavatum, and scoliosis) or hyperflexibility of joints.
Echocardiography is confirmatory with prolapse of mitral leaflets in systole into the LA.
Chest pain and palpitations are common symptoms in the young adult.
The significance of mild mitral valve prolapse (“floppy” or myxomatous mitral valve), also commonly referred to as “degenerative” mitral valve disease, has been in dispute because of the frequency with which it is diagnosed by echocardiography in even healthy young women (up to 10%). A controversial hyperadrenergic syndrome not too dissimilar to the postural orthostatic tachycardia syndrome has also been described (especially in young females) that may be responsible for some of the noncardiac symptoms observed. Fortunately, this hyperadrenergic component attenuates with age and is infrequent in persons older than 40–45 years. Some patients with mitral prolapse have findings of a systemic collagen abnormality (Marfan or Ehlers-Danlos syndrome). In these conditions, a dilated aortic root and aortic regurgitation may coexist. In many persons, the “degenerative” myxomatous mitral valve clearly leads to long-term sequelae and is the most common cause of mitral regurgitation in developed countries. Recent MRI-derived data suggest an increase in myocardial fibrosis in patients with mitral regurgitation and prolapse compared to those with mitral regurgitation without prolapse.
Patients who have only a mid-systolic click usually have no immediate clinical issues, but significant mitral regurgitation may develop, occasionally suddenly due to rupture of chordae tendineae (flail leaflet) or gradually due to progressive annular and LV dilation. The need for valve repair or replacement increases with age, so that approximately 2% per year of patients with mitral valve prolapse with clinically significant regurgitation over age 60 years will eventually require surgery.
Mitral valve prolapse without significant mitral regurgitation is usually asymptomatic but may be associated with a syndrome of nonspecific chest pain, dyspnea, fatigue, or palpitations. Most patients are young, female, thin, and some have skeletal deformities, such as pectus excavatum or scoliosis. On auscultation, there are characteristic mid-systolic clicks that may be multiple and emanate from the chordae or redundant valve tissue. If leaflets fail to come together properly, the clicks will be followed by a late systolic murmur. As the mitral regurgitation worsens, the murmur is heard more and more throughout systole. The smaller the LV chamber, the greater the degree of leaflet prolapse, and thus auscultatory findings are often accentuated in the standing position or during the Valsalva maneuver. Whether sudden cardiac death presumably due to ventricular arrhythmias is more frequent in patients with mitral valve prolapse remains controversial. Mitral prolapse progresses to significant mitral regurgitation over 3–16 years in about one-fourth of individuals.