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Mitral Valve Prolapse, Emergency Medicine

Basics

Description

- 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

- Chest pain occurs in 10%: - Sharp, localized, of variable duration, and nonexertional - Rarely may respond to nitroglycerin

- 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

- 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

- 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

  • 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 layerExcessive 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 leafletsCoronary 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 componentSometimes 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 tachycardiaUp to 40% have symptoms of dysautonomia
  • Chest pain occurs in 10%:Sharp, localized, of variable duration, and nonexertionalRarely 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 > normalArm span > height (dolichostenomelia)Scoliosis or kyphosisPectus excavatumArachnodactylyJoint 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 normalOccasionally ST-T wave depression and inversion in leads III and aVFProlonged QT interval or prominent Q wavesPremature atrial and ventricular contractions
  • CXR:Typically normalIf MR is present, may show both left atrial and ventricular enlargementCalcification 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 leafletModerate 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 murmurEvidence of nontrivial MR on EchocardiogramMen >45 yr with valve thickeningProphylaxis 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 repairSymptomatic patientsAtrial fibrillationEjection fraction <50 " 60%Left ventricular end-diastolic dimension >45 " 50 mmPulmonary 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 dysrhythmiaA family history of sudden death associated with MVPSignificant supraventricular or ventricular dysrhythmiasModerate 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)