Definition, Etiology, Pathogenesis Top
Mitral valve prolapse (MVP) is displacement of a part of one or more mitral leaflets into the left atrium during left ventricular contraction, which may or may not be associated with mitral regurgitation.
MVP syndrome (formerly termed the “floppy valve” or Barlow syndrome) is a group of symptoms, including chest pain, palpitations, arrhythmias, dizziness, and syncope, which occur in patients with MVP.
Primary MVP results from myxomatous degeneration of the leaflets and chordae tendineae; it may be familial or associated with other conditions, eg, Marfan syndrome. Secondary MVP occurs in patients with connective tissue diseases, acute endocarditis (due to a rupture of chordae tendineae), as well as ischemic heart disease (eg, due to a rupture of a papillary muscle in patients with myocardial infarction). A rupture of chordae tendineae may present as a flail leaflet. MVP may be accompanied by tricuspid valve prolapse (in 10%-20% of cases), aortic or pulmonary valve prolapse (2%-10%), and sometimes by an aneurysm or atrial septal defect.
Clinical Features and Natural HistoryTop
1. Symptoms: Chest pain, palpitations, dizziness, collapse, and syncope.
2. Signs: Typically, a mid- or late-systolic click, late-systolic or holosystolic murmur (abnormal heart sounds are more pronounced with standing; absence of these symptoms argues against MVP).
3. Natural history varies from mild, asymptomatic cases to patients at high risk of death.
Diagnosis is based on clinical features (if present) and echocardiography results.
1. Electrocardiography (ECG) is normal in the majority of patients; in some symptomatic patients, nonspecific ST-segment changes in leads II, III, and aVF (rarely in V4-V6) and arrhythmia may be observed.
2. Chest radiographs are usually normal, except for severe chronic or acute mitral regurgitation (MR).
3. Echocardiography is performed to diagnose MVP in asymptomatic patients with typical findings on auscultation, and to rule out MVP in patients with suspected MVP who have no typical findings on auscultation.
1. Asymptomatic patients or patients with mild symptoms and favorable echocardiographic findings: Reassure the patient of a good prognosis; recommend normal lifestyle, regular exercise, and follow-up every 3 to 5 years (unless there is significant MR).
2. Patients with paroxysmal palpitations accompanied by anxiety, chest pain, and fatigue: Beta-blockers may be beneficial.
3. Patients after a transient ischemic attack: Start acetylsalicylic acid 75 to 325 mg/d, unless the patient otherwise qualifies for systemic anticoagulation.
4. Patient with a history of stroke and MR, atrial fibrillation, or left atrial thrombus: Start long-term anticoagulant treatment with a vitamin K antagonist (international normalized ratio [INR], ~2.5).
5. Surgical treatment should be considered in patients with myxomatous valves and severe MR, even in the absence of symptoms, if the mitral valve has a high chance of repair in experienced surgical hands.Evidence 1Weak recommendation (benefits clearly outweigh downsides; right action for all or almost all patients). Weak rather than strong recommendation due to unclear generalizability of excellent results of repair obtained in experienced centers. Low Quality of Evidence (low confidence that we know true effects of intervention). Quality of Evidence lowered due to the observational nature of data. Suri RM, Vanoverschelde JL, Grigioni F, et al. Association between early surgical intervention vs watchful waiting and outcomes for mitral regurgitation due to flail mitral valve leaflets. JAMA. 2013 Aug 14;310(6):609-16. doi: 10.1001/jama.2013.8643. PubMed PMID: 23942679. In cases where mitral valve repair is not possible or fails, mitral valve replacement must be performed.
6. Percutaneous mitral valve repair using the edge-to-edge procedure (a mitral valve clip) is a new method of percutaneous treatment in selected patients who are ineligible for surgery because of high perioperative risk (commonly severe left ventricular dysfunction).
The prognosis is generally favorable. Factors associated with an increased risk of death include severe and possibly moderate MR, left ventricular ejection fraction <50%, unfavorable echocardiographic findings (severe thickening or elongation of a leaflet, or both), and presence of pulmonary hypertension. Patients with MVP and ≥1 of the following conditions should not engage in competitive sports: history of loss of consciousness of unexplained cause, family history of sudden cardiac death in persons with MVP, paroxysmal supraventricular arrhythmias or complex ventricular arrhythmias (particularly occurring or worsening during exercise), severe MR, left ventricular dysfunction, Marfan syndrome, long QT syndrome.