Page 47 - Medicine and Surgery

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Chapter 2: Rheumatic fever and valve disease 43

ECG is initially normal, but may show left atrial delay Aetiology

(bifid P waves, p mitrale), left ventricular hypertrophy Often there is no obvious underlying cause. Associated
or atrial fibrillation. with Marfan’s syndrome, thyrotoxicosis, rheumatic or
Echocardiography is diagnostic allowing demonstra- ischaemic heart disease. There is also a familial element.

tion and quantification of the retrograde blood flow. It is thought to be due to progressive stretching of the
The clinical effect of the valve lesion is however best valve leaflets.
assessedbymeasurementoftheleftventriculardimen-
sions(anendsystolicdimensionofover5cmindicates
Pathophysiology
ventricular decompensation).
The normal anatomy of the mitral valve prevents pro-
lapse thus one or more anomalies must be present: ex-
Management cessively large mitral valve leaflets, an enlarged mitral
Mild mitral regurgitation in the absence of symptoms
annulus, abnormally long chordae or disordered pap-
is managed conservatively, more severe disease with illary muscle contraction. During systole one of the
evidence of progressive cardiac enlargement is treated valve leaflets (usually the posterior) balloons up into
surgically. Valve repair is increasingly the operation the atrium. In some cases this causes retraction at the
of choice, but valve replacement may be required for normal point of contact of the valve cusps and hence
severely diseased valves. Papillary muscle dysfunction mitral regurgitation. The condition does not often cause
and chordal rupture may require emergency valve re- significant regurgitation.
placement.
Patients not undergoing surgery may require treat- Clinical features

ment of any complications such as cardiac failure or Most patients are asymptomatic but some complain of
atrial fibrillation. left submammary stabbing chest pain. On auscultation
Prophylaxis against infective endocarditis is required. there may be a mid-systolic click, with a late systolic

(or occasionally pansystolic) murmur if regurgitation
occurs.
Mitral valve prolase
Definition Complications
Prolapsing mitral valve is a condition in which the valve Rupture of one of the chordae may occur leading to se-
cusps prolapse into the left atrium during systole. It is vere acute valve regurgitation. Arrhythmias including
also known as floppy mitral valve. A particular form of supraventricular tachycardia and complex ventricular
prolapse may result from myxomatous degeneration of ectopy may occur. There is an increased risk of throm-
the leaflets named Barlow’s syndrome. boembolism and infective endocarditis.

Incidence Investigations
Echocardiography reveals prolapsing mitral valve in 5% ECG may be normal or show minor ST abnormalities.
of the normal population; however, not all are clinically Echocardiography shows the mid-systolic bulging of
significant, especially in the absence of any mitral in- the valve leaflets.
competence.
Management
β-blockers are used in patients with chest pain or palpi-
Age
tations. Patients with mitral valve regurgitation require
Young adulthood.
prophylaxis against infective endocarditis. Patients with
coexisting atrial fibrillation should be anticoagulated.
Sex Rarely severe cases may require valve repair or replace-
F > M ment.