Transesophageal Echo

 

 

  • TEE Main Page
  • Indications/Contraindications
  • Mid Esophageal Views
  • Transgastric Views
  • High Esophageal Views


Transesophageal echocardiography improves image quality in many ways over transthoracic echo but at the expense of being an invasive procedure. The echo probe is placed within the esophagus and ultrasound is projected at the neighboring structures, such as the heart and aorta, which are in close proximity. Because of imaging at shallower depths, TEE can use higher frequency transducers (up to 7MHz).

Becoming familiar with obtaining standard tomographic views takes some time and practice working along side an experienced echocardiographer. The standard views can be divided by how far in the TEE probe is into the esophagus or stomach. Most of the information usually is obtained in the mid-esophageal view. The transgastric views shows the LV in short and long axis and helps one obtain aortic valve gradients. It is one of the best views to evaluate left ventricular function and pericardial effusions. The high esophageal view allows visualization of the great vessels. These are discussed on separate pages.

 

 

For those interested in performing TEEs, it is crucial to know the appropriate indications for TEE as well as the risks associated with the procedure. These are outlined on below.

Common indications for TEE

1. Assessing for a cardiac source of embolus This may be a common order in a neurology ward with frequent admissions for stroke, especially of unclear etiology and especially in younger patients. Careful assessment of all valves, the left atrial appendage, the intra-atrial septum and the aorta for large friable atheroma are all important components of this study.
2. Assessing for a cardiac source of infection After an initial work-up for endocarditis TEE can be used sometime to help make a diagnosis in those with reasonable clinical suspicion or to help triage a case of known or suspected endocarditis to medical vs. surgical therapy, if for example an abscess is seen.
3. Imaging the heart before, during and after major cardiac surgery Often immediately after cardiac surgery a transthoracic echo windows are often inadequate because of recent inflammation and chest tubes and TEE is needed. In those undergoing complicated bypass and/or valve surgery pre-op and intra-operative TEE can help guide surgical therapy.
4. Assessment of congenital heart disease and associated shunts. Certain congenital anomalies uniquely seen on TEE, such as a sinus venosus ASD or anomalous pulmonary venous return.
5. Pre-cardioversion in those with atrial fibrillation for flutter. Here the left atrial appendage and atrial and ventricular structures are close examined for the presence of thrombus before cardioversion.
6. Assessment of an intracardiac masses TEE can better characterize location of intracardiac masses seen initial on TTE. Cardiac MRI is also a convenient modality for this evaluation.
7. Examination for a proximal aortic dissection When other imaging modalities are impractical because the patient has renal failure or not able to get an MRI, this becomes the test of choice.

 

 

When consenting someone for a TEE, you must look for common contraindications as shown below.

Common contraindications Relative Contraindications for
1. Known esophageal strictures, perforation, lacerations or large diverticula
2. Cervical spine instability
3. Inability to protect the airway (if not intubated).
4. Loose teeth (need a dental exam and possible extraction before proceeding)
1. Dysphagia or odynophagia
2. Recent upper GI bleeding
3. Extensive radiation to the chest and mediastinum
4. Esophageal varices

 

 

And finally you must be able to explain the risks of the procedure to a consenting individuals. These are shown below.

                                                                             Major Risks of TEE

Due to medications used for sedation: Due to intubation and probe manipulation:
1. Hypotension from sedating medications
2. Methemoglobinemia
3. Respiratory depression
4. Arrhythmia
5. Paradoxical reaction to sedating medications
6. Infection/Bleeding (from IV insertion site for IV medications)
7. Death (1/10,000)
1. Esophageal trauma, tear or perforation (1/1000 patients)
2. Aspiration
3. Upper GI bleeding
4. Dental injury, aspiration of a loose tooth
5. Displacement of endotracheal and nasogastric tubes




 

There are numerous mid-esophageal views. This page will review the most common ones you need to know as you get started, which are akin to transthoracic views. More complex views to target specific structures (for example, the left atrial appendage) are discussed elsewhere. As an overview below, they are listed below with the relevant anatomy labeled. The order in which images are acquired are based on the indication. For example if the interest is in assessing mitral valvular pathology and cause of regurgitation, then the initial images will focus on that, with the axiom that you should always try to answer the clinical question first then move to the rest of the exam.

4 Chamber View, 0 degrees

This is the standard starting view for most studies, starting with the omni at 0 degrees and no rotation. Frequently, retroflexion is needed to get a non-forshortened 4 chamber view. This view is in part used to assess RV and LV function. Note the LV wall segments are similar to that seen in the apical 4 chamber on transthoracic images. Changes in rotation along with changing the probe depth can be used to assess the pulmonary veins in this view as well, as well as better visualize the atria, which are near field structures.

 

4 Chamber View, 0 degrees, Live 2D View

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LA - left atrium, MV - mitral valve, LV - left ventricle, RV - right ventricle, RV - tricuspid valve, RA - right atrium.

 

5 Chamber View, 0 degrees

Antiflexion from the 4 chamber view will bring in the aortic root and left ventricular outflow tract. Here we are seeing the anteroseptum, similar to the 5 chamber view in transthoracic ECHO, however the apex here is farfield.

 

5 Chamber View, 0 degrees, Live 2D view

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LVOT - left ventricular outflow tract, LA - left atrium, AV - aortic valve, LV - left ventricle, RA - right atrium, RV - right ventricle.

 

2 Chamber view, 90 degrees

By keeping the probe in the same position by just using omni to 90 degrees, you will get the 2 chamber view. This is similar to the Apical 2 chamber view where often the left atrial appendage in seen.

 

2 Chamber view, 90 degrees, Live 2D view

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LA - left atrium, MV - mitral valve, LV - left ventricle, LAA - left atrial appendage, CS - coronary sinus.

 

Long Axis View, 120-140 degrees

Increasing the omni, while slightly rotating the probe counterclockwise brings in the long axis view, with similar structures seen as that in the parasternal long axis and apical long axis of transthoracic echo. This in the best view to look at the LVOT and anteroseptum as well as A2 and P2 of the mitral valve.

 

Long Axis View, 120-140 degrees, Live 2D view

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RVOT - right ventricular outflow tract, AV - aortic valve, Ao - aorta, LV - left ventricle, MV - mitral valve, LA - left atrium.

Short Axis View, 30-60 degrees

This view is commonly found perpendicular to the long axis view. So if the ideal long axis view was found at 120 degrees, then a good short axis view typically is found between 30 and 60 degrees of omni. This view is similar to the parasternal short axis view at the aortic valve level, but with different orientation of the structures.

 

Short Axis View, 30-60 degrees, Live 2D view

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Note again the non coronary cusp (NCC) is again interested by the intra-atrial septum. Look closely and in this video you will also see the left main coronary artery arising from the left coronary cusp (LCC). RCC - right coronary cusp, TV - tricuspid valve, RA - right atrium, IAS - intra-atrial septum, RVOT - right ventricular outflow tract, PV - pulmonic valve, LA - left atrium.

BiCaval View, 90-110 degrees

This is one important view which has no main equivalent in transthoracic echo like the other views shown above. Somewhere along 90-110 degrees, rotate the probe clockwise (toward the right sided structures) to obtain this view, which lays out the intra-atrial septum. This is a great view in which to look for PFOs, ASDs or to perform a bubble study. This is also an excellent view to evaluate the IVC, SVC, eustachian valve, and right atrial appendage.

 

BiCaval View, 90-110 degrees, Live 2D view

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EV - eustachian valve, IAS - intra-atrial septum, RAA - right atrial appendage, LA - left atrium, RA - right atrium.

 

 

 

 

 

 

 

  • Transgastric Main Page
  • Transgastric Short Axis
  • Transgastric Long Axis
  • Deep Transgastric

 

The transgastric views are among the most important transesophageal views and are the best TEE views for evaluating left and right ventricular function. As such, transgastric views are commonly employed in operative TEE to assess ejection fraction and wall motion post-operatively. In addition, deep transgastric views are the best views in which one can obtain accurate gradients across the aortic valve to assess the degree of aortic stenosis or regurgitation.


The transgastric short axis views are obtained by advancing the probe into the stomach and gently anteflexing. These views are similar to an inverted parasternal short axis view with the anterior wall on the bottom of the screen and the inferior wall at the top. By advancing and withdrawing the probe, short axis slices can be obtained at mitral valve level, papillary muscle level and at the LV apex. In addition, short axis views of the right ventricle, tricuspid valve and RVOT can be obtained via clockwise rotation of the probe.

 

Transgastric short axis, 0 degrees: Left Ventricle, Live 2D View

The first short axis view typically obtained is the short axis view of the left ventricle. In this view the anterior, inferior and lateral walls are well visualized as well as the ventricular septum.

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Transgastric short axis, 0 degrees: Papillary Muscle Level, Live 2D View

By withdrawing the probe further, a more basal view of the left ventricle can be obtained at the level of the papillary muscles. In some instances the LV is somewhat rotated such that electronically scanning to 30 degrees may be necessary to properly orient the left ventricle.

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Transgastric Short Axis, 0 degrees: Mitral Valve Level, Live 2D View

Withdrawing further still, the anterior and posterior mitral leaflets can be visualized in short axis as well as the anterior and posterior commissures.

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Transgastric Short Axis, 0-30 degrees: Tricuspid Valve, Live 2D View

By rotating the probe clockwise and electronically scanning to 30 degrees, the tricuspid valve can be seen in short axis. This a often a helpful TEE view to assess mechanism of tricuspid regurgitation due to restricted leaflet motion (such as pacemaker lead related scarring) vs. excess motion in a flail segment.

 

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Transgastric Short Axis, 30-60 degrees: RV Outflow Tract

 

Electronically scanning further to 30-60 degrees, and advancing the probe the muscular right ventricular outflow tract and pulmonic valve can be visualized. This is one TEE view in which Doppler across the pulmonic valve is feasible to assess degree of PS or PR.

 

Transgastric Short Axis, 30-60 degrees: RV Outflow Tract, Live 2D view

 

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Transgastric Long Axis

For any given view obtained in the short axis, a similar long axis projection can generally be obtained by electronically scanning 90 degrees from the corresponding short axis plane.

By electronically scanning to 90 degrees, one can see the entire anterior and inferior wall of the left
ventricle as well as the LV apex to evaluate for left ventricular thrombus.

Transgastric Long Axis, 90 Degrees: Left Ventricle

 

Transgastric Long Axis, 90 Degrees: Left Ventricle, Live 2D view

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Transgastric Long Axis, 90 Degrees: Mitral Valve, Live 2D view

At 90 degrees, withdrawing the probe gently allows visualization of the mitral valve leaflets, left atrium, left atrial appendage and subvalvular apparatus. This is an excellent view for evaluating mitral valve vegetations including chordal/papillary muscle involvement and for visualizing ruptured chords.

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Transgastric Long Axis, 90 Degrees: RV Long Axis, Live 2D view

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By carefully rotating the probe clockwise from the transgastric long axis view of the LV at 90 degrees, a long axis view of the RV can be obtained. This is another excellent view to assess RV function and to view the anterior wall of the RV.

 

Transgastric Long Axis, 110-130 Degrees: LVOT and Aortic Valve

By increasing the scanning angle to roughly 100-130 degrees, the left ventricular outflow tract and aortic valve can be visualized. This view is similar to an inverted parasternal long axis view.

 

Transgastric Long Axis, 110-130 Degrees: LVOT and Aortic Valve, Live 2D view

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Transgastric Long Axis, 110-130 Degrees: LVOT and Aortic Valve, Doppler

From this view, one can Doppler across the aortic valve to assess degree of aortic stenosis and regurgitation, particularly if a deep transgastric view is technically limited (see panel at left)


Deep Transgastric View, 0 Degrees

Deep transgastric views are the best TEE views for assessing aortic stenosis and regurgitation, because in general, the TEE probe can be oriented parallel to the direction of the LVOT and aortic valve. The deep transgastric views are obtained by advancing the TEE probe deep into the stomach (roughly 50-60 cm in most patients) and gently anteflexing. They can be challenging to obtain in some patients.

 

Deep Transgastric View, 0 Degrees - Live 2D View

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The deep transgastric view is similar to the apical 5 chamber view obtained in transthoracic imaging. Note that the continuous wave cursor can be oriented essentially parallel to the aortic valve from this view (left panel) to allow accurate measurement of gradients across the aortic valve to assess degree of AS/AR.

 

 

 

 

 

 

 

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High esophageal views are helpful for evaluating the great vessels including the aortic root and coronary arteries, ascending aorta and the pulmonary artery. A useful landmark for obtaining many of the high esophageal views is the mid-esophageal view of the aortic valve in short axis at 40-60 degrees. By withdrawing from the level of the aortic valve, the origin of the coronary arteries can be visualized.

 

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This allows visualization of the origin of the left main coronary artery arising from the left coronary cusp of the aortic valve and in some instances the LAD and LCX (the latter running towards the left atrium in the AV groove).

 

 

 

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By withdrawing further from the aortic valve level, the ascending aorta can be visualized in short axis and the pulmonary artery can be followed in long axis to the PA bifurcation.

 

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The final high esophageal views generally obtained are views of the ascending aorta, aortic arch and proximal descending thoracic aorta. The proximal ascending aorta is best visualized from the long axis, roughly 100-110 degrees and with gentle anteflexion, withdraw the probe to see the ascending aorta until contact is lost. This is an excellent view for the assessment of Type A aortic dissection.

 

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The descending aorta and distal arch can be seen in short axis at 0 degrees, by rotating toward the aorta from the mid esophageal position and slowly withdrawing the probe. In newer TEE systems with 3-D capabilities, x-plane is often used to view the aorta in both short axis (left) and long axis (right) to ensure that dissection and atherosclerotic plaque are not missed.

 

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Withdrawing the probe further, the aortic arch and in some instances the head and neck vessels can be visualized. Again, it is often useful to use biplane to see the arch in long axis (left) and short axis (right). This view is helpful to evaluate the aortic arch in patients with cryptogenic strokes or suspected systemic emboli to exclude aortic arch atheroma. Note that grade III or IV atheroma (4mm thickness and/or mobile elements) discovered on TEE in patients with stroke is an indication for anticoagulation.