Transesophageal Echocardiography (TEE): Views and Applications

Transesophageal echocardiography (TEE) places a miniaturized ultrasound transducer in the esophagus and stomach, using the heart’s close proximity to the esophagus to obtain higher-resolution images than transthoracic echocardiography can achieve — particularly of posterior structures like the left atrium, atrial septum, mitral valve, and thoracic aorta. It is semi-invasive, requires sedation, and is indicated when TTE is unable or unlikely to answer the clinical question. This page covers the standard view protocol, patient preparation and safety, and the major clinical applications of TEE.

The Comprehensive TEE Examination: 28 Standard Views

The ASE/SCA “Guidelines for Performing a Comprehensive Transesophageal Echocardiography Examination” define a set of 28 standard views across four probe levels — midesophageal (ME), transgastric (TG), deep transgastric, and upper esophageal (UE)/aortic — each with a defined transducer angle range. This is a formal, named protocol intended for consistency in training, reporting, and quality assurance, not an informal sweep through angles. The number and order of views acquired can vary with the clinical indication, but the underlying view definitions are standardized. A systematic exam generally proceeds through three parts, in this order: the midesophageal windows, then the transgastric windows, then the aortic windows.

Midesophageal (ME) Views

Obtained with the probe positioned behind the left atrium, roughly 30–40 cm from the incisors — the workhorse level for most of the examination.

• ME five-chamber view (~0–10°) and ME four-chamber view (~0–10°, reached by advancing and/or retroflexing from the five-chamber view) — the LA, RA, LV, RV, mitral valve, and tricuspid valve, plus the LVOT and aortic valve in the five-chamber view.
• ME mitral commissural view (~50–70°) — an intermediate view between the four-chamber and two-chamber views, showing the mitral valve’s commissural scallops (P3–A2–P1), papillary muscles, and chordae.
• ME two-chamber view (~80–100°) — the LV, LA, mitral valve, coronary sinus, and left atrial appendage. Note that this sits at 80–100°, not simply “90° from the four-chamber view” as a single mechanical step — the mitral commissural view lies between them in the standard sequence.
• ME long-axis (LAX) view (~120–140°) — the LV, LA, LVOT, RVOT, mitral valve, aortic valve, and proximal ascending aorta in one plane. A closely related ME AV LAX view sits at the same angle range, reached by a slight withdrawal and anteflexion from the long-axis view.
• ME aortic valve short-axis (AV SAX) view (~25–45°) — the aortic valve leaflets en face, RA, LA, and RVOT. This is a narrower and lower angle range than sometimes assumed; it is not the same range as the mitral commissural view despite both lying in the 25–70° region generally.
• ME RV inflow-outflow view (~50–70°) — the RA, LA, tricuspid valve, RVOT, and pulmonic valve in one plane, useful for tricuspid pathology and RVOT assessment.
• ME bicaval view (~90–110°) — the SVC, IVC, RA, and interatrial septum, obtained by adjusting probe depth to center both venae cavae. A related ME modified bicaval tricuspid valve view (~50–70°) adds detail on the tricuspid valve and mid-interatrial septum.
• ME left atrial appendage (LAA) view (~90–110°) — a dedicated view of the LAA and left upper pulmonary vein, distinct from (though nearby in angle to) the bicaval view. This is the primary view for LAA thrombus evaluation and pre-closure planning, and deserves acquisition as its own named view rather than an incidental finding on the two-chamber view.

Transgastric (TG) Views

Obtained by advancing the probe into the stomach, roughly 40–45 cm from the incisors, and flexing anteriorly.

• TG basal, mid-papillary, and apical short-axis views (~0–20° each, distinguished by probe depth/advancement rather than angle) — three distinct standard views along the LV’s short axis, from base to apex, for regional wall motion and global function assessment. These are named as three separate views in the comprehensive protocol, not a single “transgastric short-axis view.”
• TG RV basal view and TG RV inflow-outflow view (~0–20°) — dedicated right-heart views from the transgastric position.
• TG two-chamber view (~90–110°) — the LV, LA, mitral valve, and left atrial appendage.
• TG right ventricular inflow view (~90–110°) — the RV, RA, and tricuspid valve.
• TG long-axis (LAX) view (~120–140°) — the LV, LVOT, aortic valve, aortic root, and mitral valve. This sits distinctly higher than the TG two-chamber view — the two are easy to conflate since both originate from the same transgastric probe position, but they are separate named views at different angle ranges.
• Deep transgastric five-chamber view (~0–20°, reached by further advancing and left-flexing the probe) — aligns the ultrasound beam with the LVOT and aortic valve for spectral Doppler interrogation, used to measure transaortic velocities and gradients when the standard five-chamber alignment is suboptimal.

Upper Esophageal (UE) and Aortic Views

• UE aortic arch long-axis view (~0–10°) and UE aortic arch short-axis view (~70–90°) — two distinct views at nearly opposite ends of the rotation range, not a continuous 0–90° sweep. For the aortic arch, the convention is effectively reversed from most cardiac structures: 0° shows the long axis and ~90° shows the short axis, because the esophagus runs roughly parallel to the arch rather than across it.
• UE right and left pulmonary veins view (~90–110°) — reached by withdrawing from the bicaval view and rotating clockwise (right veins) or counterclockwise (left veins).
• Descending aorta short-axis view (~0–10°) and descending aorta long-axis view (~90–100°) — obtained at the transgastric-to-midesophageal transition, useful for atherosclerotic plaque, dissection, and thrombus screening along the length of the vessel.

Patient Preparation

• Fasting — follows standard aspiration-precaution timing: at least 6 hours for solids and at least 4 hours for liquids (including tube feedings), per local institutional guidelines.
• Positioning — left lateral decubitus, which also minimizes aspiration risk during probe insertion.
• Monitoring — continuous ECG, pulse oximetry, and blood pressure measurement (every 2–3 minutes) throughout the procedure; capnography is recommended with moderate sedation, since it has been shown to reduce respiratory complications; patients with an ASA classification of 3 or higher should have telemetry.
• Sedation — conscious sedation is typical (for example, midazolam 2–4 mg), with deep sedation generally not advisable; sedation-reversal agents (such as flumazenil 0.3–0.6 mg) and resuscitation equipment must be available.
• Probe insertion — advanced along a posterior and medial line through the pharynx with the head slightly flexed, while the patient attempts to swallow. The upper esophageal sphincter typically offers mild resistance that eases as the probe passes; strong, elastic resistance suggests the tip is caught in a piriform recess, and no force should ever be applied against resistance during intubation.
• Post-procedure — the patient should remain NPO for at least 1 hour to allow topical anesthesia to wane, avoid driving for the rest of the day, and be examined for signs of complications before discharge.

Safety and Contraindications

TEE has a low complication rate when performed by trained operators with appropriate patient selection: the rate of complications serious enough to interrupt the procedure is under 1%, with a reported mortality rate under 1 in 10,000 patients. Most possible complicating conditions are relative, not absolute, contraindications:

• Absolute contraindications — esophageal stricture, mass, or perforation; active upper GI bleeding; recent esophageal or upper GI surgery; an uncooperative patient.
• Relative contraindications — esophageal diverticulum or varices, previous esophageal surgery, dysphagia, and coagulopathy or thrombocytopenia. Notably, the procedure can generally be performed safely even with therapeutic levels of systemic anticoagulation, and anticoagulation alone is not a reason to defer a clinically indicated TEE.

Known complications include laryngospasm, arrhythmias (both fast and slow), esophageal perforation, and hemorrhage from an esophageal tumor if one is present; methemoglobinemia is a specific, recognized risk of the topical anesthetics prilocaine and benzocaine. Initial concern that TEE might increase endocarditis risk has not been borne out by evidence of post-procedure bacteremia, so most physicians do not routinely use antibiotic prophylaxis.

Clinical Applications

TEE’s superior resolution of posterior structures and its role in real-time procedural guidance make it central to several clinical scenarios:

• Cardiovascular source of embolism — in stroke or TIA workup, TEE screens the LV apex, aortic and mitral valves, ascending/descending aorta and arch, left atrial appendage (with PW Doppler for flow velocity and attention to spontaneous echo contrast), the left atrial body, and the atrial septum/fossa ovalis (with contrast and Valsalva maneuver for PFO detection).
• Infective endocarditis — the mitral valve is examined in multiple cross-sections, the aortic valve in both long- and short-axis views, with particular attention to short-axis views of the aortic valve and root to rule out a perivalvular abscess. See Infective Endocarditis for the broader diagnostic picture.
• Aortic dissection and aneurysm — the ascending aorta in long- and short-axis (noting maximal diameter, an intimal flap, intramural hematoma, or periaortic fluid), the descending aorta and arch, aortic valve function and the mechanism of any regurgitation, the relationship of the dissection to the coronary ostia, and color Doppler assessment of flow (or its absence) in a false lumen.
• Mitral regurgitation — mechanism and origin mapped to specific leaflets and scallops via the transgastric basal short-axis view and multiple lower esophageal views, color Doppler of the regurgitant jet (proximal jet width and convergence zone), and pulmonary venous pulsed Doppler. See Mitral Valve Prolapse and Mitral Stenosis.
• Prosthetic valve evaluation — assessment of obstruction (reduced leaflet/disc mobility, elevated CW Doppler velocities), regurgitation (mapped to transprosthetic vs. paraprosthetic origin), structural changes (calcification, immobilization, leaflet rupture or perforation), and paraprosthetic complications (vegetation, thrombus, pannus, abscess, or fistula). See Prosthetic Heart Valves.
• Intraoperative and interventional guidance — monitoring valve repair (mitral and aortic), monitoring LV function in high-risk surgical patients, and guiding transcatheter interventions including TAVI, transcatheter mitral repair, paravalvular leak closure, and ASD or LAA closure.
• Pericardial effusion and tamponade — evaluating effusion presence and hemodynamic severity, and guiding pericardiocentesis when TTE access is limited.

Advantages and Limitations

TEE’s proximity to the heart minimizes interference from lung tissue, ribs, and body habitus, giving substantially better resolution of posterior structures than TTE — but this comes with real trade-offs. It is semi-invasive and requires sedation, carries the (uncommon but real) risks and contraindications outlined above, and requires a skilled, trained operator for both acquisition and interpretation. It remains a complement to TTE rather than a routine replacement for it, reserved for the specific clinical questions TTE cannot adequately answer.