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Transesophageal Echocardiography: Indications and Views

Indications and Contraindications

Class I Indications

Transesophageal echocardiography serves as an indispensable diagnostic and procedural guidance tool in scenarios where transthoracic imaging is insufficient or when superior resolution is required for clinical decision-making. The evaluation of native and prosthetic valve endocarditis represents one of the most important Class I indications, particularly when TTE is non-diagnostic or when complications such as perivalvular abscess, fistula, or prosthetic dehiscence are suspected. Intraoperative monitoring during cardiac surgery, including valve repair and replacement, coronary artery bypass grafting, and congenital heart surgery, relies heavily on real-time TEE assessment to evaluate surgical results and guide intraoperative decisions. TEE has become essential for guidance of percutaneous structural interventions, including transcatheter aortic valve replacement, transcatheter edge-to-edge mitral repair with MitraClip, left atrial appendage occlusion with devices such as WATCHMAN, atrial septal defect and patent foramen ovale closure, and balloon mitral valvuloplasty. When CT is unavailable or the patient is too hemodynamically unstable for transport, TEE provides rapid assessment of aortic dissection at the bedside. Evaluation of cardiac source of embolism when TTE is non-diagnostic represents another critical indication, as TEE offers superior visualization of the left atrial appendage for thrombus detection, patent foramen ovale and atrial septal defect assessment, and characterization of aortic atheroma. Pre-cardioversion evaluation for atrial fibrillation or flutter lasting longer than 48 hours or of unknown duration, when anticoagulation has not been therapeutic, requires TEE to exclude left atrial appendage thrombus before safe cardioversion can proceed.

Class II Indications

Class II indications encompass situations where TEE provides incremental diagnostic value beyond TTE. Assessment of mitral valve anatomy for surgical planning is particularly important, as TEE precisely localizes prolapsing segments according to the Carpentier classification, which directly influences the surgical repair strategy. Hemodynamic assessment in critically ill patients when TTE windows are inadequate is another common scenario, particularly in the intensive care unit where body habitus, mechanical ventilation, and surgical dressings may preclude adequate transthoracic imaging. Evaluation of aortic pathology including intramural hematoma, penetrating aortic ulcer, and traumatic aortic injury benefits from the proximity of the esophagus to the aorta. Assessment of congenital heart disease such as Ebstein anomaly, atrioventricular canal defects, and sinus venosus atrial septal defects often requires the superior resolution of TEE for comprehensive characterization. Guidance of pericardiocentesis when the subcostal TTE window is inadequate is occasionally necessary.

Absolute and Relative Contraindications

Absolute contraindications to TEE include esophageal perforation, esophageal stricture, active upper gastrointestinal bleeding, recent esophageal or gastric surgery within six weeks, and known esophageal diverticulum such as a Zenker diverticulum. Relative contraindications include esophageal varices, cervical spine instability, severe coagulopathy with an INR exceeding 3 or platelets below 50,000, Barrett esophagus, and prior radiation to the mediastinum.

TEE Probe Manipulation and Orientation

Probe Controls

The TEE probe provides multiple degrees of freedom for comprehensive cardiac imaging. The multiplane angle rotates the imaging plane electronically through 0 to 180 degrees, allowing visualization of structures in virtually any orientation without physically repositioning the probe. The large wheel controls anteflexion and retroflexion, deflecting the probe tip anteriorly or posteriorly. The small wheel provides rightward and leftward flexion for lateral tip deflection. Advancing or withdrawing the probe changes the depth of the imaging plane within the esophagus or stomach. By standard convention, the left side of the display screen corresponds to the patient's right side when imaging at 0 degrees.

Four Principal Probe Positions

The upper esophageal position, located approximately 20 to 25 cm from the incisors, provides views of the aortic arch and great vessels. The mid-esophageal position at 30 to 35 cm from the incisors is the most commonly used location, where the majority of cardiac views are obtained including the four-chamber, two-chamber, long-axis, aortic valve, and bicaval views. The transgastric position at 40 to 45 cm provides short-axis and long-axis views of the left ventricle as well as RV inflow views. The deep transgastric position at 45 to 50 cm with maximal anteflexion aligns the Doppler beam parallel to flow through the LVOT and aortic valve, enabling accurate hemodynamic measurements.

Comprehensive TEE Examination: 28-View Protocol

Mid-Esophageal Views (0-135 degrees)

ME Four-Chamber (0 degrees)

The mid-esophageal four-chamber view at 0 degrees displays all four cardiac chambers along with the mitral and tricuspid valves, the interatrial septum, and the interventricular septum. This view is the starting point for evaluating atrial septal defects and patent foramen ovale using agitated saline contrast injection. Assessment of mitral and tricuspid regurgitation severity and biventricular function is performed from this window. The A2 and P2 scallops of the mitral valve, representing the central portions of the anterior and posterior leaflets, are best visualized in this view.

ME Commissural View (60 degrees)

Rotating to 60 degrees produces the commissural view, which displays the P3, A2, and P1 scallops of the mitral valve from left to right across the image. Both commissures become visible, making this view essential for localizing mitral valve prolapse and identifying commissural pathology.

ME Two-Chamber (90 degrees)

At 90 degrees, the two-chamber view displays only the left atrium and left ventricle, showing the anterior and inferior walls. The left atrial appendage is prominently visualized in this view. Pulsed-wave Doppler interrogation within the LAA measures emptying velocity, where values below 20 cm/s are associated with thrombus formation and spontaneous echo contrast. LAA morphology is classified into four types relevant to LAA occlusion device sizing: chicken wing (48% prevalence), cactus (30%), windsock (19%), and cauliflower (3%).

ME Long-Axis (120-135 degrees)

The mid-esophageal long-axis view at 120 to 135 degrees provides an image equivalent to the transthoracic parasternal long-axis view. The LVOT, aortic valve, proximal ascending aorta, and mitral valve (A2 and P2 scallops) are all visible. This view is critical for LVOT diameter measurement for hemodynamic calculations and for systematic measurement of aortic root dimensions including the annulus, sinuses of Valsalva, sinotubular junction, and ascending aorta.

ME AV Short-Axis (30-45 degrees)

The aortic valve short-axis view at 30 to 45 degrees displays the aortic valve en face, revealing all three cusps (non-coronary, right coronary, and left coronary). This view is essential for assessing bicuspid valve morphology, identifying vegetations, and evaluating calcification. The interatrial septum with the thin fossa ovalis region is visible for evaluating PFO and ASD. The coronary ostia can be visualized, with the left main coronary artery arising from the left coronary cusp and the right coronary artery from the right coronary cusp.

ME AV Long-Axis (120-135 degrees)

The aortic valve long-axis view at 120 to 135 degrees shows the aortic valve in its long-axis orientation, displaying the LVOT, the right coronary and non-coronary cusp leaflets, and the ascending aorta. Systematic aortic root measurements from the annulus through the ascending aorta are obtained from this view, which is critical for TAVR sizing. Assessment of aortic regurgitation jet characteristics including vena contracta width and jet width relative to the LVOT is optimally performed here.

ME Bicaval View (90-110 degrees)

The bicaval view at 90 to 110 degrees displays the superior vena cava on the right side of the screen, the right atrium, the interatrial septum, and the inferior vena cava on the left side. Important structures visible include the Eustachian valve at the IVC orifice, the Chiari network, and the crista terminalis. This view is the primary window for evaluating PFO and ASD with color Doppler and agitated saline contrast. During structural interventional procedures, the bicaval view provides real-time visualization of transseptal puncture, showing the characteristic tenting of the interatrial septum by the needle and catheter.

ME RV Inflow-Outflow (60-90 degrees)

At 60 to 90 degrees, the RV inflow-outflow view demonstrates the RVOT wrapping around the aortic root, with the tricuspid valve, right ventricle, and pulmonic valve all visible. This view is valuable for assessing tricuspid valve pathology, pulmonic stenosis or regurgitation, and RVOT masses.

<image> A comprehensive TEE imaging plane diagram showing 8 key mid-esophageal views arranged in a circular layout around a central heart illustration. Each view should be labeled with the name, multiplane angle, and key structures visible. Views included: ME 4-chamber (0 deg), ME commissural (60 deg), ME 2-chamber (90 deg), ME LAX (120 deg), ME AV SAX (30-45 deg), ME AV LAX (120-135 deg), ME bicaval (90-110 deg), ME RV inflow-outflow (60-90 deg). The central heart should show the probe in the esophagus behind the LA with dotted lines indicating imaging planes at different angles. Use a consistent color scheme: blue for right-sided structures, red for left-sided structures, green for valves. Each mini-image should be a schematic representation of the echo view with labeled chambers. </image>

Transgastric Views

TG Mid Short-Axis (0 degrees)

The transgastric mid short-axis view at 0 degrees produces the classic "donut" appearance of the left ventricle at the papillary muscle level. All six wall segments at this level are visible, representing all three coronary artery territories, making this the intraoperative gold standard for real-time ischemia monitoring. Both the posteromedial and anterolateral papillary muscles are identifiable in this view.

TG Basal Short-Axis (0 degrees, withdraw slightly)

By withdrawing the probe slightly from the mid short-axis position while maintaining 0 degrees, the basal short-axis view displays the mitral valve in short axis with its characteristic fish-mouth opening pattern. This view enables direct planimetry for mitral valve area measurement in mitral stenosis and facilitates assessment of commissural fusion and leaflet calcification.

TG Two-Chamber (90 degrees)

Rotating to 90 degrees in the transgastric position produces a long-axis view of the left ventricle showing the anterior and inferior walls, along with the mitral valve chordae and papillary muscles. This view is particularly useful for detailed assessment of the subvalvular mitral apparatus.

TG RV Inflow (90-120 degrees, rightward rotation)

With rightward rotation at 90 to 120 degrees, the transgastric RV inflow view displays the tricuspid valve, right ventricle, and right atrium in long axis. This view is valuable for characterizing tricuspid valve pathology, including the apical displacement of the septal leaflet seen in Ebstein anomaly (displacement of 8 mm/m squared or more) and the thickened, retracted, fixed leaflets characteristic of carcinoid heart disease.

Deep Transgastric (0 degrees, deep with anteflexion)

The deep transgastric view is obtained at 0 degrees by advancing the probe deep into the stomach with maximal anteflexion. This position aligns the LVOT and aortic valve parallel to the Doppler beam, which is critical for obtaining accurate aortic valve gradient measurements using continuous-wave Doppler when mid-esophageal views yield suboptimal beam alignment. Verification of aortic valve area calculations by the continuity equation is performed from this position.

Upper Esophageal and Aortic Views

UE Aortic Arch Long-Axis (0 degrees)

The upper esophageal aortic arch long-axis view at 0 degrees displays the aortic arch and the origins of the great vessels, including the innominate artery, left common carotid artery, and left subclavian artery. This view is important for assessing dissection flaps, aortic atheroma, and coarctation.

UE Aortic Arch Short-Axis (90 degrees)

At 90 degrees, the short-axis view of the aortic arch shows the arch in cross-section along with the pulmonary artery bifurcation and the left pulmonary artery. The relationship to the left recurrent laryngeal nerve, which has surgical relevance, is appreciated in this projection.

Descending Aorta Short-Axis (0 degrees) and Long-Axis (90 degrees)

By withdrawing from the stomach to the upper esophagus while rotating posteriorly, the descending aorta can be systematically evaluated in both short-axis (0 degrees) and long-axis (90 degrees) orientations. Assessment focuses on identifying atheroma (graded I through V), intramural hematoma, dissection flaps, and penetrating ulcers. Grade IV and V complex aortic atheroma, defined as 4 mm or more in thickness or containing mobile components, is associated with increased stroke risk.

<image> A detailed illustration of the left atrial appendage (LAA) assessment by TEE. Show four panels representing the four morphological types of LAA: (1) Chicken wing - single dominant lobe with sharp bend, (2) Cactus - central lobe with secondary lobes, (3) Windsock - single dominant lobe without bend, (4) Cauliflower - complex with multiple small lobes. Each panel should show the 2D TEE image schematic with the LAA shape outlined in yellow, labeled with the morphology name and its prevalence (chicken wing 48%, cactus 30%, windsock 19%, cauliflower 3%). Below the four panels, include a PW Doppler tracing from within the LAA showing normal emptying velocity waveform (>40 cm/s) versus low velocity pattern (<20 cm/s, associated with thrombus risk), with velocity scale and labels. </image>

TEE-Guided Procedures

Transseptal Puncture Guidance

TEE guidance for transseptal puncture utilizes primarily the bicaval view at 90 to 110 degrees, where real-time visualization of the interatrial septum tenting by the needle and catheter confirms the puncture location. Complementary short-axis imaging at 0 to 30 degrees verifies the anterior-posterior positioning of the puncture site. The target is the fossa ovalis, the thinnest portion of the interatrial septum, though the specific location within the fossa is adjusted based on the planned procedure: posterior and inferior for MitraClip, mid-fossa for WATCHMAN device implantation, and superior for pulmonary vein isolation procedures. Injection of agitated saline through the side-arm of the transseptal sheath confirms proper positioning before the septum is crossed.

MitraClip/TEER Guidance

TEE guidance for transcatheter edge-to-edge repair involves real-time three-dimensional en face visualization of the mitral valve from the left atrial perspective, providing the "surgical view" orientation. Biplane imaging displays simultaneous LVOT and commissural views for precise clip positioning between the anterior and posterior leaflets. After each clip deployment, MR reduction is assessed using color Doppler, pulsed-wave Doppler interrogation of the pulmonary veins for systolic flow reversal, and transmitral gradient measurement. A mean gradient exceeding 5 mmHg after clip placement raises concern for iatrogenic mitral stenosis. Successful leaflet insertion is confirmed by demonstration of independent leaflet motion on either side of the clip, creating a "double orifice" configuration.

TAVR Guidance

TEE during TAVR provides complementary annulus sizing (though CT remains the definitive sizing modality) using the mid-esophageal AV long-axis view. Post-deployment assessment involves a systematic color Doppler sweep from 0 to 180 degrees to localize and grade any paravalvular leak, measurement of the mean transvalvular gradient, and assessment of valve position relative to the coronary ostia. Continuous monitoring throughout the procedure screens for complications including pericardial effusion and tamponade, new wall motion abnormalities suggesting coronary obstruction, new or worsened mitral regurgitation, conduction abnormalities, and aortic root injury.

LAA Occlusion Device (WATCHMAN)

TEE is essential for LAA occlusion device implantation, providing detailed assessment of LAA orifice diameter, depth, and morphology for device selection and sizing. Devices are typically oversized by 10% to 20% relative to the LAA orifice measurement. Post-deployment evaluation uses color Doppler to detect residual peri-device leak (less than 5 mm is generally considered acceptable), confirms stable device position, and ensures the absence of compression on adjacent structures including the left superior pulmonary vein and left circumflex coronary artery.

3D Echocardiography

Acquisition Modes

Three-dimensional echocardiography offers several acquisition modes with distinct advantages. Live 3D uses a narrow sector to provide real-time imaging with the highest temporal resolution, making it ideal for procedural guidance. Zoom 3D provides a focused full-volume acquisition of a specific structure and is the preferred mode for detailed valve analysis. Full-volume acquisition captures a wider sector through ECG-gated multi-beat acquisition, typically stitching together 4 to 7 consecutive cardiac cycles. While this produces the most comprehensive 3D dataset, it is susceptible to stitch artifacts when used in patients with arrhythmias. 3D color Doppler performs full-volume color flow acquisition that enables detailed characterization of regurgitant jets and direct measurement of the vena contracta area.

Clinical Applications

The mitral valve is one of the most important applications of 3D echocardiography. The en face view from the left atrial perspective provides the "surgical orientation" that precisely localizes prolapsing segments according to the Carpentier classification (P1 through P3, A1 through A3), identifies clefts in the leaflet tissue, and characterizes commissural anatomy. For the aortic valve, the en face view enables direct planimetry of the aortic valve area, confirmation of bicuspid morphology, and detailed vegetation characterization. The interatrial septum is optimally assessed with 3D for ASD sizing, rim assessment, and device sizing. LV volumes and ejection fraction measured by 3D echo are more accurate and reproducible than 2D Simpson method calculations because they avoid both apical foreshortening and the geometric assumptions inherent in biplane methodology.

<image> A detailed surgical view of the mitral valve as seen from 3D TEE, oriented in the standard surgical perspective (aortic valve at 12 o'clock position). The mitral valve should be shown en face from the left atrial side with all six scallops clearly labeled: A1, A2, A3 (anterior leaflet segments) and P1, P2, P3 (posterior leaflet segments). Mark the anterolateral commissure (near LAA, labeled) and posteromedial commissure (near coronary sinus, labeled). Show the aortic valve at 12 o'clock as a reference landmark. Include a small inset showing the corresponding Carpentier classification diagram with the same nomenclature. Use anatomic coloring with leaflet tissue in pink-tan, labeled white text with black outline for readability. The LAA should be visible at approximately the 9 o'clock position. </image>

Key Clinical Pearls

• Always perform a focused history for esophageal disease and bleeding risk before TEE; bite guard protects the probe and patient's teeth
• LAA thrombus is best excluded using multiple TEE planes (45, 90, 135 degrees) with careful differentiation from pectinate muscles; PW Doppler emptying velocity < 20 cm/s and dense SEC increase thrombus probability
• The "blind spot" of TEE is the distal ascending aorta and proximal arch (air in the trachea/left mainstem bronchus interposed) -- CT or epiaortic scanning is needed for this region
• For TAVR sizing, CT is the gold standard due to the elliptical annulus geometry; TEE provides complementary real-time guidance but underestimates the major annular dimension due to 2D tomographic limitation
• A transmitral mean gradient > 5 mmHg after MitraClip should prompt reassessment of clip number and position to avoid iatrogenic mitral stenosis
• Probe temperature monitoring: modern probes auto-lock at 43 degrees C; prolonged procedures increase thermal injury risk to esophageal mucosa

References

• Hahn RT, et al. Guidelines for Performing a Comprehensive Transesophageal Echocardiographic Examination: Recommendations from the ASE. J Am Soc Echocardiogr. 2013;26:921-964.
• Nicoara A, et al. Guidelines for the Use of Transesophageal Echocardiography to Assist with Surgical Decision-Making in the Operating Room. J Am Soc Echocardiogr. 2020;33:692-734.
• Zamorano JL, et al. EAE/ASE Recommendations for the Use of Echocardiography in New Transcatheter Interventions. Eur Heart J. 2011;32:2189-2214.
• Lang RM, et al. EAE/ASE Recommendations for Image Acquisition and Display Using 3D Echocardiography. J Am Soc Echocardiogr. 2012;25:466-498.

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