B.36 Mitral Valve Prolapse Syndrome Flashcards
B.36 Mitral Valve Prolapse Syndrome
define
Mitral valve prolapse (MVP) is caused by a structural defect of the mitral valve that results in mitral leaflets bulging into the left atrium during systole.
B.36 Mitral Valve Prolapse Syndrome
epidemiology
Prevalence: 2–3 % (one of the most common valvular abnormalities in the US)
The most common cause of mitral regurgitation in developed countries
B.36 Mitral Valve Prolapse Syndrome
etiology
Mostly idiopathic
Connective tissue disorders: Marfan syndrome, Ehlers-Danlos syndrome, osteogenesis imperfecta
Fragile X syndrome
Myocardial infarction: infarction of papillary muscles → rupture of chordae tendineae → mitral valve prolapse
Acute rheumatic heart disease
Infective endocarditis
Autosomal dominant polycystic kidney disease
B.36 Mitral Valve Prolapse Syndrome
pathophys
The most common underlying pathology in the case of mitral valve prolapse is myxomatous degeneration (deposition of glycosaminoglycan such as dermatan sulfate) of the mitral valve due to a primary disease or connective tissue disorder
Long, floppy mitral valve leaflets with excessive valvular tissue → the mitral annulus becomes dilated and the chordae tendineae become elongated (and may rupture) → prolapse of one or both mitral valve leaflets into the left atrium during systole
The leaflets may also exhibit fibrous thickening at regions where they rub against each other.
Mitral valve prolapse sets into motion a vicious cycle of events.
Prolapse of mitral valve leaflets into the left atrium → ↑ tension on the chordae tendineae and papillary muscles → ischemia of the papillary muscles with weakening of the chordae tendineae → further prolapse of the mitral valve
If prolapse happens without the rupture of chordae tendineae → mitral valve leaflets billow into the left atrium → mild to moderate mitral regurgitation
If the papillary muscles become severely ischemic and the chordae tendineae rupture → mitral valve leaflets flail about in the left atrium → severe mitral regurgitation
B.36 Mitral Valve Prolapse Syndrome
clinical
Most patients are asymptomatic.
Rarely: atypical chest pain and anxiety
In case of complications: fatigue, dyspnea, cough, syncope, and palpitations
Auscultatory findings
Mitral valve prolapse click: high-frequency, midsystolic click that is best heard at the mitral region
High-frequency, mid-to-late systolic murmur that is best heard at the mitral region and may radiate to the axilla (squatting diminishes the murmur)
Patients with severe MR: S3 may be heard as a result of left ventricular overload (especially in the left decubitus position)
B.36 Mitral Valve Prolapse Syndrome
DX
ECG: mostly normal
Transthoracic echocardiography (test of choice) to confirm diagnosis
Echocardiographic definition of MVP: displacement of the mitral valve during systole by more than 2 mm above the mitral valve annulus in the parasternal long-axis view
Classical MVP (∼ 60%): leaflet thickness ≥ 5 mm
Non-classical MVP (∼ 40%): leaflet thickness < 5 mm
Transesophageal echocardiography (TEE) is used as an adjunct to TTE and intraoperatively to guide mitral valve repair procedures.
B.36 Mitral Valve Prolapse Syndrome
TX
No treatment is required in most cases.
Patients with severe mitral regurgitation
: mitral valve repair or replacement
Additional treatment is required when complications arise
B.36 Mitral Valve Prolapse Syndrome
Complications
Atrial fibrillation
Ventricular ectopics : MVP patients with ventricular ectopics should be asked to avoid caffeine; β-blockers may be used for symptomatic relief.
Transient ischemic attacks (TIA) and/or stroke : Patients who experience TIA or stroke will require prophylactic doses of aspirin
Infective endocarditis: MVP patients with a past history of infective endocarditis require prophylaxis against infective endocarditis
Right heart failure
Sudden cardiac death (rare)
B.36 Mitral Valve Prolapse Syndrome
MVP murmur increases with squatting – true or false?
❌ False. Squatting increases preload → ↓ murmur intensity.
B.36 Mitral Valve Prolapse Syndrome
MVP always causes mitral regurgitation – true or false?
❌ False. Many MVP cases have no MR.
B.36 Mitral Valve Prolapse Syndrome
MVP murmur is pansystolic – true or false?
❌ False. It’s typically mid-to-late systolic following the click.
B.36 Mitral Valve Prolapse Syndrome
What is the most characteristic auscultation finding in mitral valve prolapse?
→ Mid-systolic click, often followed by a late systolic murmur
B.36 Mitral Valve Prolapse Syndrome
How does the MVP murmur change with Valsalva?
→ It becomes louder and earlier (due to ↓ preload)
B.36 Mitral Valve Prolapse Syndrome
Can MVP cause sudden cardiac death?
✅ Rarely — only in high-risk patients with ventricular arrhythmias or bileaflet prolapse
B.36 Mitral Valve Prolapse Syndrome
What is first-line treatment for symptomatic MVP with palpitations?
→ Beta-blockers
B.36 Mitral Valve Prolapse Syndrome
What is the surgical indication in MVP?
→ Severe mitral regurgitation causing LV dysfunction or symptoms
