Mitral Valve Prolapse

Mitral Valve Prolapse

Victoria E. Judd

Mitral valve prolapse (MVP) is the most common cardiac disorder diagnosis, with childhood prevalence estimates of 0.5% to 17%. The overall prevalence in the general population is 2% to 4%, with no gender difference. Early studies, which used less specific echocardiographic criteria, had the estimated incidence much higher, particularly for young women.

MVP occurs most frequently as a primary condition characterized by myxomatous degeneration of the leaflets. Primary MVP usually is sporadic. Familial clustering of MVP of autosomal dominant inheritance has been reported. MVP may occur in association with other conditions such as Marfan syndrome, Ehlers-Danlos syndrome, and other diseases that affect connective tissue.

Secondary MVP refers to the MVP that does not have myxomatous valvular changes. It may occur with leaner body mass index and smaller left ventricle cavity size.


Associated conditions are described in Box 279.1.

Clinical Presentation

Most children with MVP are asymptomatic and initially are referred for cardiac evaluation because a click and/or a murmur is detected during a routine examination. Numerous studies report a high incidence of symptoms with MVP, but they probably are due to selection bias. Small subgroups of patients may be highly symptomatic. However, little direct evidence links these symptoms with MVP. Symptoms may include chest pain, fatigue, weakness, palpitations, dyspnea, dizziness, near syncope, syncope, anxiety, and orthostatic hypotension.

Abnormalities on physical examination include thoracic and skeletal abnormalities, such as a tall slender habitus, pectus excavatum, pectus carinatum, scoliosis, or kyphosis. A high arched palate, increased joint laxity, or abnormal dermatoglyphics patterns also may be present.

MVP is characterized by a midsystolic click or a late systolic murmur. The click and murmur vary, depending on an affected patient’s position, and may vary in auscultatory findings at different times in different patients. The change in the click and murmur is caused by alterations in left ventricular volume. Such maneuvers as moving from a sitting to a supine position or from a standing to a squatting position, passive leg raising, and maximal isometric exercise increase left ventricular volume and decrease the degree of MVP and mitral regurgitation. The click and murmur move toward the second heart sound, and the murmur is shorter.

Left ventricular size and left ventricular volume are decreased by administration of amyl nitrate; a Valsalva maneuver; sudden change from a supine to a sitting position, from a sitting
to a standing position, and from a squatting to a standing position; and inspiration. MVP and mitral valve regurgitation increase; thus, the click and murmur move toward the first heart sound, and the murmur becomes longer. Because of the changing intensity or timing with different body positions, auscultation should be performed with the patient in many positions.

The high-pitched, low-intensity, nonejection midsystolic click is heard best at the apex of the heart. It may occur from just after the first heart sound to just before the second heart sound. Multiple clicks may be present in certain patients. Usually, the crescendo, the late systolic murmur of MVP, is preceded by a click and is heard best at the apex. Occasionally, the murmur is described as having a honking or whooping quality and may be heard without a stethoscope.

The murmur of MVP may be confused with the murmur of hypertrophic cardiomyopathy. During the strain of the Valsalva maneuver, the murmur of hypertrophic cardiomyopathy increases in intensity and the murmur of MVP becomes longer but not louder.

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Jul 24, 2016 | Posted by in ORTHOPEDIC | Comments Off on Mitral Valve Prolapse

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