Approach

Often patients with mitral valve prolapse (MVP) are asymptomatic, and auscultatory findings prompt further evaluation. Expert physical exam alone is highly sensitive for MVP, but specificity is limited. Diagnosis is typically established by echocardiography.[1][2][3]

Initial clinical evaluation

The classic finding on cardiac auscultation is a midsystolic click, followed by a medium- to high-pitched, late-systolic murmur of varying duration. The click is generated by the tensing of the mitral apparatus as the leaflets prolapse. The murmur is caused by mitral regurgitation (MR). The typical mid- to late-systolic click and murmur of MVP is distinct from the holosystolic murmur of MR resulting from torn chordae tendineae.

Dynamic maneuvers can be used to alter the timing of the click during systole.

With a decrease in preload (standing, Valsalva) or decrease in afterload (amyl nitrate administration), the click and murmur occur earlier in systole. Conversely, with an increase in left ventricular (LV) volume (squatting) or increase in afterload (handgrip) the click and murmur occur later.

Echocardiogram

When clinical exam suggests MVP, an echocardiogram is indicated. This establishes the diagnosis by detecting a leaflet prolapse of ≥2 mm above the level of the annulus during systole in the long-axis parasternal view. It also assesses additional important features such as the presence of left-sided chamber enlargement, leaflet morphology, and the presence and severity of MR.[1][2][3]​​ Mitral annular disjunction (MAD) can be diagnosed by noting the presence of a gap between the base of the posterior mitral leaflet and the LV myocardium, also called “atrialization” of the posterior leaflet. Chronic, hemodynamically significant MR can cause pulmonary hypertension.[26]​ The effect of chronic MR on LV systolic function can be latent, and ejection fraction can remain in the normal range when contractility is already impaired.[23][Figure caption and citation for the preceding image starts]: Parasternal long-axis echocardiogram of mitral valve illustrating prolapse of posterior leaflet (red arrow)From the personal collection of Brian Griffin, MD; used with permission [Citation ends].com.bmj.content.model.Caption@74f27b38

Palpitations or syncope

The correlation between palpitations and MVP is complex and incompletely understood. MVP is found to be associated with malignant ventricular arrhythmias and sudden cardiac arrest in up to 4% of individuals. Myocardial fibrosis and presence of MAD are found to be additional risk markers for ventricular arrhythmia.[28]​ Evaluation of palpitations or syncope should mirror the workup in patients without MVP, including evaluation with Holter or ambulatory event monitoring to rule out significant arrhythmias.

Cardiac magnetic resonance imaging (MRI)

Cardiac MRI is an option for patients with unsatisfactory echocardiogram or marked echocardiographic discrepancy with clinical findings. Cardiac MRI adds information about underlying mechanisms, providing accurate quantification of regurgitation, chamber volumes, and myocardial viability. Delayed enhancement in papillary muscle and basal inferior wall may indicate increased arrhythmia risk. LV fibrosis on cardiac MRI is associated with cardiac events including heart failure, arrhythmia, and death.[3][29][30]​​ Cardiac MRI and positron emission tomography-computed tomography are recommended for further evaluation of patients with MVP when infective endocarditis is suspected, providing detailed visualization of cardiac structures, and detection of inflammation or infection.​[31]

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