Rosen & Barkin's 5-Minute Emergency Medicine Consult (454 page)

• 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
  

• History and auscultation of a midsystolic click are often sufficient to make the diagnosis.
  
• Echocardiography confirms the diagnosis when clinical information is insufficient.
  

Not required to establish the diagnosis

• 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
      

Cardiac studies may be indicated in patients with chest pain when the etiology is uncertain.

• 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

• ABCs
  
• IV access
  
• Supplemental oxygen
  
• Cardiac monitoring
  
• Pulse oximetry
  

• Cardiac monitoring
  
• Supplemental oxygen
  
• IV catheter placement
  

• Medications generally are not necessary. β-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.
  
• β-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.
    

• 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
  

• 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

• Severe MR
  
• Severe chest pain with ischemic symptoms
  
• Syncope or near syncope
  
• Life-threatening dysrhythmias
  
• Cerebral ischemic events, including transient ischemic attack
  

• Asymptomatic
  
• No lab abnormalities
  
• No significant MR or dysrhythmias
  

• 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.

• 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
    

• 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.
  

• 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

424.0 Mitral valve disorders

BASICS