Mitral valve prolapse

Published on 02/04/2015 by admin

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Last modified 22/04/2025

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20 Mitral valve prolapse

Instruction

Examine this patient’s heart.

Salient features

History

• Palpitations associated with mild tachyarrhythmias

• Increased adrenergic symptoms

• Chest pain

• Anxiety or fatigue.

Examination

• Midsystolic click followed by late or midsystolic murmur

• Look for features of Marfan syndrome (high arched palate, arm span greater than height).

Notes

• Squatting will bring the midsystolic click closer to the second heart sound and decrease the duration of the murmur.

• A Valsalva manoeuvre and standing have the opposite effect.

• The midsystolic murmur begins after the first heart sound; the late systolic murmurs begin after the first heart sound but continue to or through the second heart sound (S2). Both types of murmur may have a crescendo–decrescendo configuration

Diagnosis

This patient has mitral valve prolapse (lesion) and a long pansystolic murmur, indicating significant mitral regurgitation, which will require prophylaxis for infective endocarditis (functional status).

Questions

What are eponyms for mitral valve prolapse?

Barlow syndrome (Br Heart J 1968;30:203), click–murmur syndrome, floppy mitral valve.

What is the prevalence in the normal population?

The new awareness that the mitral valve is saddle shaped rather than a planar valve has resulted in new echocardiographic definition for mitral valve prolapse as one or both mitral leaflets exhibit at least 2 mm displacement superior to the long-axis annular plane (a line connecting the annular hinge points), with or without leaflet thickening (Fig. 20.1). With this new description, the prevalence of prolapse is estimated at 2–3%, and is equally distributed between men and women.

image

Fig. 20.1 Transthoracic echocardiographic image in parasternal long-axis view, showing posterior mitral leaflet (PML) bowing backward and prolapsing into left atrium during systole.

(With permission from Hayek E et al. 2005.)

What are the complications of mitral valve prolapse?

• Severe mitral regurgitation

• Arrhythmias: ventricular premature contractions, ventricular tachycardia, paroxysmal supraventricular tachycardia

• Atypical chest pain

• Transient ischaemic attacks, embolism

• Infective endocarditis in those with mitral regurgitation

• Sudden death.

Mention a few associated conditions

• Marfan syndrome

• Chronic rheumatic heart disease

• Ischaemic heart disease

• Cardiomyopathies

• 20% of patients with atrial septal defects—secundum type

• Ehlers–Danlos syndrome

• Psoriatic arthritis

• Ebstein’s anomaly

• SLE.

How would you manage such patients?

• Reassure the asymptomatic patient

• Relief of atypical chest pain with analgesics or beta-blockers (empiric treatment)

• Aspirin or anticoagulants in those with transient ischaemic attacks

• Antiarrhythmics in those with frequent tachyarrhythmias or ventricular premature contractions

• Prophylaxis for infective endocarditis (see Case 17)

• Consider surgery in those with severe mitral regurgitation.

Advanced-level questions

What is the mechanism of click in the mitral valve prolapse?

Clicks result from sudden tensing of the mitral valve apparatus as the leaflets prolapse into the left atrium during systole

What do you know about Carpentier’s nomenclature of the mitral valve?

Anatomically, the posterior and anterior leaflets of the mitral valve each may be divided into three sections:

• Three posterior leaflet scallops: the lateral (P1), middle (P2), and medial (P3)

• Three anterior segments: lateral (A1), middle (A2) and medial (A3).

Which segments of the mitral valve commonly prolapse?

• Most cases of prolapse involve the posterior middle scallop (easily identified on long-axis echocardiographic images)

• Lateral scallop prolapse (not clearly seen on long-axis images; this aspect is best seen in the apical four-chamber view).

John Barlow, South African Professor of Cardiology.

The term mitral valve prolapse was introduced in 1966 by Criley et al. (Br Heart J 1966;28:488–96) and has been frequently used as a synonym for ‘billowing mitral leaflet’, which was used by Barlow et al. (Br Heart J 1968;30:203–18) to describe the same condition.

The French surgeon Carpentier suggested that the term prolapse should be reserved to indicate that the free edge of the leaflet protrudes beyond the mitral annulus level during systole (J Thorac Cardiovasc Surg 1983;86:323–37), whereas the term billowing should be used when the leaflet body bulges into the left atrium, overriding the mitral annulus plane and usually maintaining the free edge of the leaflets on the ventricular side (Am J Cardiol 1985;55:501–2), although the two conditions may coexist.

Notes

• Superior leaflet displacement in a four-chamber view should not be judged diagnostic of prolapse. Therefore, transthoracic echocardiography can confirm the diagnosis of prolapse but may not be able to exclude lateral scallop prolapsed without taking into account several planes of imaging. Transoesophageal echocardiography is, consequently, very effective in identifying prolapsing segments.

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