Basics
Description
- Bulging of 1 or both of the mitral valve leaflets into the left atrium during systole
- Occurs when the leaflet edges of the mitral valve do not coapt
- Commonly due to abnormal stretching of 1 of the mitral valve leaflets during systole:
- Myxomatous proliferation of the spongiosa layer within the valve causing focal interruption of the fibrosa layer
- Excessive stretching of the chordae tendineae, leading to traction on papillary muscles
- Theoretical explanations for associated chest pain:
- Focal ischemia from coronary microembolism due to platelet aggregates and fibrin deposits in the angles between the leaflets
- Coronary artery spasm
- Mitral regurgitation (MR) may occur in some patients.
- Age of onset is 10 " 16 yr
- Female > male (3:1)
- Typically benign in young women, whereas men >50 yr tend to have serious sequelae and more often develop severe regurgitation requiring surgical intervention
- Can be identified by ECG in 2 " 4% of the general population and in 7% of autopsies
- A variety of neuroendocrine and autonomic disturbances occur in some patients
- Genetics:
- Strong hereditary component
- Sometimes transmitted as an autosomal dominant trait with varying penetrance
Etiology
- Marfan syndrome
- Relapsing polychondritis
- Ehlers " Danlos syndrome (i.e., types I, II, IV)
- Osteogenesis imperfecta
- Pseudoxanthoma elasticum
- Stickler syndrome
- Systemic lupus erythematosus
- Polyarteritis nodosa
- Polycystic kidney disease
- von Willebrand syndrome
- Duchenne muscular dystrophy
Diagnosis
Signs and Symptoms
Separated into 3 categories:
- Symptoms related to autonomic dysfunction
- Symptoms related to the progression of MR
- Symptoms that occur as a result of an associated complication (i.e., stroke, endocarditis, or arrhythmia)
History
- Palpitations in up to 40% of cases:
- Usually ventricular premature beats or paroxysmal supraventricular tachycardia
- Up to 40% have symptoms of dysautonomia
- Chest pain occurs in 10%:
- Sharp, localized, of variable duration, and nonexertional
- Rarely may respond to nitroglycerin
- Panic attacks
- Anxiety
- Fatigue
- Depression in up to 70%
- Nervousness
- Migraine headaches
- Irritable bowel
- Syncope/presyncope:
- Occurs in 0.9% of patients
- Orthostasis
- Dyspnea and fatigue relatively uncommon
Physical Exam
- Mid to late systolic click at the cardiac apex:
- Standing or Valsalva moves click closer to S1.
- S1 may be accentuated when prolapse occurs early in systole.
- Squatting moves click closer to S2.
- Late systolic murmur
- Skeletal abnormalities are observed in 2/3 of patients:
- Asthenic body habitus: Height-to-weight ratio > normal
- Arm span > height (dolichostenomelia)
- Scoliosis or kyphosis
- Pectus excavatum
- Arachnodactyly
- Joint hypermobility
- Hypomastia
- Cathedral palate
Essential Workup
- History and auscultation of a midsystolic click are often sufficient to make the diagnosis.
- Echocardiography confirms the diagnosis when clinical information is insufficient.
Diagnosis Tests & Interpretation
Lab
Not required to establish the diagnosis
Imaging
- EKG:
- Usually normal
- Occasionally ST-T wave depression and inversion in leads III and aVF
- Prolonged QT interval or prominent Q waves
- Premature atrial and ventricular contractions
- CXR:
- Typically normal
- If MR is present, may show both left atrial and ventricular enlargement
- Calcification of the mitral annulus in patients with Marfan syndrome
- Echocardiography:
- Classic MVP: The parasternal long-axis view shows >2 mm superior displacement of the mitral leaflets into the left atrium during systole, with a leaflet thickness of at least 5 mm.
- Nonclassic MVP: Displacement is >2 mm, with a maximal leaflet thickness of <5 mm.
- Other ECG findings that should be considered as criteria are leaflet thickening, redundancy, annular dilatation, and chordal elongation.
- Minor criteria:
- Isolated mild to moderate superior systolic displacement of the posterior mitral leaflet
- Moderate superior systolic displacement of both mitral leaflets
Diagnostic Procedures/Surgery
Cardiac studies may be indicated in patients with chest pain when the etiology is uncertain.
Differential Diagnosis
- MI/ischemia
- Hypertrophic cardiomyopathy with obstruction
- Idiopathic hypertrophic subaortic stenosis
- Tachyarrhythmias
- Atrial fibrillation/flutter
- Ventricular septal defect
- Papillary muscle dysfunction
- Hypokalemia
- Hypomagnesemia
- Valvular heart disease
- Pheochromocytoma
- Anemia
- Thyrotoxicosis
- Pregnancy
- Toxicity from cocaine, amphetamines, or other sympathomimetics
- Ventricular tachycardia
- WPW syndrome
- Rheumatic endocarditis
- Anxiety/panic disorder
- Stress
- Menopause
Treatment
Pre-Hospital
- ABCs
- IV access
- Supplemental oxygen
- Cardiac monitoring
- Pulse oximetry
Initial Stabilization/Therapy
- Cardiac monitoring
- Supplemental oxygen
- IV catheter placement
Ed Treatment/Procedures
- Medications generally are not necessary. ²-blockers may be helpful if palpitations are severe.
- Antiplatelet agents (aspirin, aspirin with extended-release dipyridamole, or clopidogrel) are indicated for patients with transient ischemic attack or stroke symptoms.
- Orthostatic hypotension and presyncope symptoms may be treated with sodium chloride tablets; however, if this treatment is not successful, fludrocortisone may be used.
- Magnesium supplementation may improve symptoms of the classic MVP syndrome.
- Significant MR in the setting of HTN (systolic blood pressure >140 mm Hg) may be improved with the use of ACE inhibitors.
- ²-Blockers:
- Patients with tachycardia or severely symptomatic chest pain
- Digoxin is an alternative for supraventricular tachycardia and prevention of chest pain and fatigue.
- Antibiotic prophylaxis:
- When performing surgical procedures (e.g., contaminated wound repair, abscess incision and drainage)
- Indicated in the following settings:
- Presence of a murmur
- Evidence of nontrivial MR on Echocardiogram
- Men >45 yr with valve thickening
- Prophylaxis is not recommended for patients who have an isolated click without a murmur or for patients without evidence of MR on an echocardiogram or previous history of endocarditis.
Medication
First Line
- Amoxicillin: 2 g PO 1 hr before the procedure (peds: 50 mg/kg PO 1 hr before procedure)
- Ampicillin: 2 g IV/IM 30 min before the procedure (peds: 50 mg/kg IV/IM 30 min before the procedure)
- Clindamycin: 600 mg PO 1 hr before procedure (peds: 20 mg/kg PO 1 hr before procedure; not to exceed 600 mg)
- Propranolol: 1 " 3 mg IV at 1 mg/min, 80 " 640 mg/d PO (peds: 1 " 4 mg/kg/d PO div. BID/QID
- Isoproterenol: 0.02 " 0.06 mg IV 1, 0.01 " 0.02 mg IV or 2 " 20 mg/min infusion
- Atenolol: 0.3 " 2 mg/kg/d PO, max. 2 mg/kg/d
Second Line
- Digoxin: 0.5 " 1 mg IV/IM div. 50% initially then 25% 2 q6 " 12h or 0.125 " 0.5 mg/d PO
- Fludrocortisone: 0.05 " 0.10 mg/d PO
Follow-Up
Disposition
Admission Criteria
- Severe MR
- Severe chest pain with ischemic symptoms
- Syncope or near syncope
- Life-threatening dysrhythmias
- Cerebral ischemic events, including transient ischemic attack
Discharge Criteria
- Asymptomatic
- No lab abnormalities
- No significant MR or dysrhythmias
Issues for Referral
- Cardiology consultation is warranted in cases of ventricular dysrhythmia or risk of sudden death, as well as when symptoms of severe MR are present.
- Cardiothoracic surgery follow-up is recommended for consideration of valve replacement or repair
- Symptomatic patients
- Atrial fibrillation
- Ejection fraction <50 " 60%
- Left ventricular end-diastolic dimension >45 " 50 mm
- Pulmonary systolic pressure >50 " 60 mm Hg
- Valve repair rather than replacement is preferred to avoid the need for anticoagulation.
- Pilots with mitral valve prolapse may develop MR under positive G force and be at risk for dysrhythmia or syncope.
Dysrhythmias, sudden death, and bacterial endocarditis have been reported.
- Often present in an atypical manner:
- More likely to have holosystolic murmurs and a greater degree of MR.
- Heart failure may be presenting symptom complex associated with ruptured chordae tendineae.
MVP does not predispose women to any increased risk during pregnancy.
Follow-Up Recommendations
- Repeat evaluations are necessary every 3 " 5 yr to identify any progression of disease.
- Infective endocarditis prophylaxis is indicated in patients with MVP and MR while undergoing at-risk procedures.
- Coronary artery anomalies should be excluded in patients with chest pain before they participate in sports.
- Patients with MVP and a murmur should avoid high-intensity competitive sports in the following settings:
- Syncope associated with dysrhythmia
- A family history of sudden death associated with MVP
- Significant supraventricular or ventricular dysrhythmias
- Moderate to severe MR
Pearls and Pitfalls
- The diagnosis of MVP should not be an excuse to terminate further diagnostic evaluation of patients with symptoms of chest pain, palpitations, dyspnea, or syncope.
- MVP is the 3rd most common cause of sudden death in athletes.
Additional Reading
- Avierinos JF. Risk, determinants, and outcome implications of progression of mitral regurgitation after diagnosis of mitral valve prolapse in a single community. Am J Cardiol. 2008;101(5):662 " 667.
- Guntheroth W. Link among mitral valve prolapse, anxiety disorders, and inheritance. Am J Cardiol. 2007;99(9):1350.
- Salem DN. Valvular and structural heart disease: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th edition). Chest. 2008;133(6 suppl):593S " 629S.
- Turker Y, Ozaydin M, Acar G, et al. Predictors of ventricular arrhythmias in patients with mitral valve prolapse. Int J Cardiovasc Imaging. 2010;26:139 " 145.
- Weisse AB. Mitral valve prolapse: Now you see it; now you don 't: Recalling the discovery, rise and decline of a diagnosis. Am J Cardiol. 2007;99(1):129 " 133.
- Wilson W, Taubert KA, Gewitz M, et al: Prevention of infective endocarditis. A guideline from the American Heart Association. Circulation. 2007;116:1736 " 1754.
Codes
ICD9
424.0 Mitral valve disorders
ICD10
I34.1 Nonrheumatic mitral (valve) prolapse
SNOMED
- 409712001 mitral valve prolapse (disorder)