Functional, constitutional or degenerative
disorder of the mitral valve.
Mitral Valve Prolapse; Familial Mitral Regurgitation;
Floppy Mitral Valve; Familial Myxomatous Valvular Disease; Myxomatous Mitral
Valve Prolapse; Myxomatous Degeneration of the Mitral Valve.
Mitral valve prolapse (MVP) is found in 3 to 5% of
adults. The predominance in young female adults disappears in the older
In the majority of idiopathic MVP cases,
inheritance is autosomal dominant. In some cases, it is linked to chromosome
16p. Penetrance of MVP is variable.
In approximately 80% of cases (typically
children or young females), MVP is considered a functional consequence of a
valve-ventricle mismatch. In these patients, MVP and mitral regurgitation
(MR) tend to resolve slowly over time, and the prognosis is generally good.
In a minority of cases (20%), MVP is the result of progressive myxomatous
degeneration of the mitral valve leaflets. These patients, mostly males,
develop severe MR and eventually left ventricular dysfunction. With
worsening MR, progressive pulmonary hypertension ensues. Valve replacement
is needed after an average of approximately 25 years.
Echocardiography, family history, and clinical
examination. Secondary forms must be excluded.
Typical midsystolic click can be heard in
approximately 80% of cases. Common features of functional MVP are
recurrent chest pain, dyspnea episodes, palpitations, syncopes, and
an increased anxiety level. Individuals with this form of MVP typically have a
lean body stature. Complications from functional MVP are rare and include
endocarditis, arrhythmias, and probably a slightly increased risk of
thromboembolic events. Arrhythmias are of supraventricular origin, or they
manifest as premature ventricular contractions. A higher incidence of
preexcitation syndromes has been reported. Fortunately, malignant
ventricular arrhythmias are rare. In an analysis of 50 patients with sudden
cardiac death related to surgery and/or anesthesia, 47 (94%) had cardiac
lesions on autopsy, but MVP was found in only one (2%). Atrial
fibrillation is common in patients with progressive myxomatous
degeneration. Symptoms and complications of pulmonary hypertension and left
ventricular dysfunction become more pronounced in advanced disease stages.
One child had a cerebrovascular event in a follow-up study of 119 children
with MVP. Electrocardiographic recordings were abnormal in 63%, with premature ventricular
contraction and T-wave inversion noted most commonly. There was no case of
Personal medical history should
include palpitations, syncope, anesthesia, and current medication (e.g.,
beta-blocking agents, anxiolytics, anticoagulants). The electrocardiogram might identify
patients with atrial fibrillation or preexcitation syndromes, but is
unreliable in terms of predicting arrhythmias during anesthesia. Electrolytes should
be in the normal range. Adequate anxiolysis reduces palpitations. The degree
of MR and any additional cardiac anomalies should be known; when in doubt,
echocardiography may be necessary.
Adequate intravascular filling reduces
symptoms of functional MVP. However, fluid administration must be carefully
titrated to prevent deterioration of MR. For the same reason, an increase of
systemic afterload (vasoconstriction) must be prevented, and vasodilators
might be considered as long as normotension is maintained. ...