refers to a condition of the various four heart valves. With
reference to the mitral valve it refers to systolic billowing
of one or both mitral leaflets into the left atrium, with or
without mitral regurgitation (see fig.115,
fig. 117a). Disease processes
involving any one or more of these components may result in
dysfunction of the valvular apparatus and prolapse of the mitral
leaflets toward the left atrium during systole when left ventricular
pressure exceeds left atrial pressure.
Tests for Mitral Valve Prolapse Include:
Myocardial Perfusion Scintigraphy,
Cardiac Catheterization and
Echocardiography is the most useful noninvasive
test for defining MVP.The M-mode echocardiograhic definition
of MVP include 2 mm or more of posterior displacement of one
or both leaflets of holosystolic posterior "hammocking"of
more than 3 mm (see Fig.116). On
2-D echocardiography, systolic displacement of one or both mitral
leaflets, particularly when they coapt on the LA side of the
annular plane, in the parasternal long-axis view indicates a
high likelihood of MVP (Fig.116).
There is disagreement concerning the reliability of an echocardiographic
diagnosis of MVP when observed only in apical four-chamber view.
The diagnosis of MPV is even more certain when the leaflet thickness
is greater than 5 mm during ventricular diastole. Leaflet redundancy
is often associatedh an elongated mitral annulus and elongated
chordae. On Doppler velocity recordings, the presence or absence
of MR is an important consideration, and MVP is more when the
MR is detected as a high-velocity jet midway posterior in the
At present, there is no consensus on the 2-D echocardigraphic
criteria for MVP. Since echocardiography is a tomographic cross-sectional
technique, no single view should be considered diagnostic. The
parasternal long-axis view permits visualization of the medial
aspect of the anterior mitral leaflet and middle scallop of
the posterior leaflet. If findings of prolapse are localized
to the lateral scallop of the posterior leaflet, they would
be best visualized by the apical four-chamber view. All available
echocardiographic views should be used, with the provision that
anterior leaflet billowing alone in the four-chamber apical
view is not evidence of prolapse; however, a displacement of
the posterior leaflet or the coaptation point in any view including
the apical views suggests the diagnosis of prolapse. The echocardiographic
criteria for MVP should include structural changes such as leaflet
thickening, redundancy, annular dilatation, and chordal elongation.
Patients with echocardiographic criteria for MVP but without
evidence of thickened/redundant leaflets or definite MR are
more difficult to classify. If such patients have auscultatory
findings typical of MVP, the echocardiogram confirms the diagnosis.
On the other hand, a patient with typical auscultatory findings
but a negative echocardiogram likely also has MVP; in the past,
as many as 10 percent of patients with MVP have had a nondiagnostic
echocardiographic study. Currently, this percentage is lower
because of more careful and complete echocardiographic studies.
In clinical practice, a false diagnosis of MVP occurs too frequently.
The use of echocardiography as a screening test for MVP in patients
with and without symptoms who have no systolic click or murmur
on serial,carefully performed ausculatory examinations is not
recommended, as the likelihood of finding MVP is extremely low.
the various causes of mitral valve prolapse (MVP) there is a
primary one in which there is a marked proliferation of the
spongiosa, the delicate myxomatous connective tissue between
the atrialis (a thick layer of collagen and elastic tissue forming
the atrial aspects of the leaflet) and the fibrosa or ventricularis,
which is composed of dense layers of collagen and forms the
basic support of the leaflet. This myxomatous proliferation
causes focal disruption of the fibrosa the leaflets become fibrous
and the chordae tendineae become thin and elongated (see fig.115,
This particular form of MVP maybe familial, non-familial, and
also caused by a disease called Marfan's syndrome and other
connective tissue diseases. MVP may also be due to coronary
artery disease, rheumatic heart disease, cardiomyopathies, and
"flail" mitral valve leaflet(s).
The majority of patients with mitral valve
prolapse(MVP) are asymptomatic and lack a high risk profile.
These patients with mild or no symptoms and
findings of milder forms of prolapse should be reassured of
a benign prognosis.A normal life-style and regular exercise
is encouraged. It is recommended that antibiotic prophylaxis
for the prevention of infective endocarditis while undergoing
procedures associated with bacteremia for most patients in whom
the diagnosis is definite.
Patients with MVP and palpitations associated
with sinus tachycardia or mild tachyarrhythmia and those with
chest pain, anxiety, or fatigue often respond to therapy with
In many cases, however, the cessation of catecholamines
stimulants such as caffeine, alcohol, cigarettes, and certain
drugs may be sufficient to control symptoms.
Orthostatic symptoms (dizziness, fainting)
are best treated with volume expansion preferably by liberalizing
fluid and salt intake. Mineralocorticoid therapy may be needed
in severe cases, and wearing support stockings may be beneficial.
In those with complex arrhythmias, specific
therapy should be guided by monitoring techniques, including
electrophysiology testing when indicated.
Daily aspirin therapy is recommended for
MVP patients with documented focal neurologic deficits,avoiding
cigarette smoking and oral contraceptives. Use of anticoagulants
may be indicated in those who have suffered a stroke. Restriction
from competitive sports is recommended when moderate heart enlargement,
left ventricular dysfunction, uncontrolled arrhythmias, unexplained
syncope, prolonged QT interval alone or in combination occur.
There is a familial occurrence. There is no
contraindication to pregnancy based on the diagnosis of MVP
Patients with severe mitral regurgitation
with symptoms and/impaired left ventriclar function require
cardiac catheterization and evaluation for mitral valve surgery,
including repair or replacement, with a low operative mortality
and excellent short term results and less emboli and infection.
Asymptomatic patients with no significant mitral regurgitation
can be evaluate every 2-3 years.
High risk patients including those with severe
regurgitation should be followed more frequently, even if no
symptoms are present.