Mitral Stenosis in Emergency Medicine Workup

Updated: Dec 28, 2015
  • Author: Ethan S Brandler, MD, MPH; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Workup

Laboratory Studies

Brain natriuretic peptide may be useful in determining the presence of heart failure in an undifferentiated patient with dyspnea. [24]

Troponin I and creatinine kinase levels may be useful in excluding acute myocardial infarction in patients who present with symptomatic mitral stenosis (MS).

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Imaging Studies

Two-dimensional (2D) and Doppler echocardiography is the preferred initial diagnostic modality. [11] It initially confirms diagnosis and also assesses valve function whenever symptoms or physical examination findings change. [25, 26] See the video below.

Echocardiography of mitral stenosis. Courtesy of Michael B. Stone, MD, RDMS.

2D echocardiography evaluates the morphology of the mitral valve. Orifice size can be measured. Leaflet mobility, thickness, calcification, and fusion may be noted. Additionally, 2D echocardiography allows evaluation of the structure and potential disease in the cardiac chambers and other valves.

Doppler echocardiography is the most accurate noninvasive technique to quantify the hemodynamic severity of mitral stenosis at rest or with exercise. It measures the transvalvular pressure gradient and the pulmonary arterial pressure and determines whether mitral regurgitation, aortic regurgitation, and other valvular abnormalities coexist.

If 2D echocardiography is inadequate or inconclusive, transesophageal echocardiography (TEE) may be indicated. TEE provides better images of the mitral valve anatomy and is a more sensitive way to detect pathology such as valvular vegetations or atrial thrombus; anomalies that should be identified before valvotomy is pursued.

Although currently it may not be as readily available, studies show that 3-dimensional (3D) echocardiography is superior to 2D echocardiography in the evaluation of mitral valve stenosis because it can provide useful information on mitral valve area measurements. [27]

Use chest radiography to look for left atrial, pulmonary artery, right ventricle, and/or right atrium enlargement (eg, straightening of left heart border, loss of aortic window). Rarely, calcification of the mitral valve may be seen. Radiologic changes in the lung fields indirectly reflect the severity of mitral stenosis. Interstitial edema manifests as Kerley B lines. Severe, long-standing mitral obstruction results in Kerley A lines.

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Other Tests

ECG is relatively insensitive for mild mitral stenosis.

Ninety percent of patients with significant mitral stenosis and sinus rhythm display electrical evidence of left atrial enlargement. P-mitrale in lead II and/or a biphasic P wave in lead V1 with a wide negative deflection greater than 0.04 seconds is observed.

The QRS axis in the frontal plane correlates with the severity of valve obstruction in pure mitral stenosis. A mean axis 0-60 º suggests a mitral valve area of more than 1.3 cm2, whereas an axis of more than 60 º suggests a valve area less than 1.3 cm2.

Atrial fibrillation usually develops in the presence of preexisting left atrial enlargement. With severe pulmonary hypertension, right-axis deviation and right ventricular hypertrophy can be seen. The ECG of right ventricular hypertrophy typically shows tall R waves in the right chest leads, and the R wave may be taller than the S wave in lead V1. In addition, right-axis deviation and right precordial T-wave inversions are often present.

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Procedures

Exercise stress testing

Exercise stress testing is indicated in situations where the degree of disability is in question.

Stress echocardiography provides information about changes in the transmitral gradient and the degree of limitation of exercise and may guide decisions about valvotomy.

Cardiac catheterization

Cardiac catheterization is indicated when a discrepancy is noted between Doppler-derived hemodynamics and the clinical status in a symptomatic patient.

Perform percutaneous mitral balloon valvotomy in properly selected patients.

Cardiac catheterization measures absolute left-sided and right-sided pressure when pulmonary artery pressure elevation is out of proportion to mean gradient and valve area.

Coronary angiography may be performed in selected patients.

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