Version May 2024
INTRODUCTION — Although transthoracic echocardiography (TTE) remains the cornerstone of diagnostic cardiac ultrasound, transesophageal echocardiography (TEE) is a valuable complementary tool. As compared with TTE, TEE offers superior visualization of posterior cardiac structures because of close proximity of the esophagus to the posteromedial heart with lack of intervening lung and bone. This proximity permits use of high-frequency imaging transducers that afford superior spatial resolution.
The first practical clinical use of TEE was described in 1976 when a modified rigid endoscopic probe with single M-mode crystal was used [1]. Since that time, TEE technology has evolved rapidly with developments in flexible endoscopic probe technology, phased-array ultrasound systems, and crystal miniaturization and real time three-dimensional (3D) imaging. Current TEE probes allow for both two-dimensional (2D) and 3D imaging as well M-mode, spectral Doppler, and color flow Doppler. The versatility of these transducers permits improved penetration with lower frequency imaging and superior spatial resolution with higher frequency imaging. Additional developments have focused on further probe miniaturization/pediatric probes and improvement of 3D echocardiography capability. (See "Echocardiography essentials: Physics and instrumentation".)
The indications, potential complications, and normal views associated with TEE will be reviewed here. The role for TEE in the evaluation of specific cardiac abnormalities is discussed in detail separately. (See "Transesophageal echocardiography in the evaluation of the left ventricle" and "Transesophageal echocardiography in the evaluation of aortic valve disease" and "Transesophageal echocardiography in the evaluation of mitral valve disease".)
INDICATIONS FOR TEE — Both TTE and TEE have a variety of clinical indications and applications. In most patients, TEE provides superior image quality, particularly for posterior cardiac structures which are nearer to the esophagus and less well visualized on transthoracic echocardiography as they are more distant from the anterior TTE transducer. Because of its moderately invasive nature, however, TEE is reserved for selected indications in which the potential benefits of making a diagnosis outweigh the risks associated with the procedure. For many but not all clinical situations, a TTE study precedes the TEE as the TTE study may obviate or help guide the TEE.
How often TEE is used for a particular indication varies from institution to institution. However, TEE is most commonly performed to evaluate for a potential cardiac source of embolus, to assess valves for endocarditis, or to exclude left atrial appendage (LAA) thrombi in patients with atrial fibrillation [2]. In a large series from the 1990s, the most common clinical indications for TEE were to evaluate for cardiac source of embolism, endocarditis, prosthetic heart valve dysfunction, native valvular disease, and aortic dissection or aneurysm [3]. Although thoracic computed tomography is frequently used for the assessment of aortic aneurysm/dissection, TEE may still be utilized for diagnosis in some acute scenarios. In current practice, TEE is also performed with many cardiac surgical procedures, especially those involving congenital or valve repairs, both to verify preoperative diagnosis and anatomy and to monitor the success of the procedure [4]. In addition, TEE is commonly used for imaging guidance during noncoronary percutaneous cardiac interventions, such as transcatheter mitral valve repair and transcatheter left atrial appendage closure. (See "Clinical features and diagnosis of acute aortic dissection", section on 'Diagnosis'.)
TTE remains the initial test of choice for most patients requiring an echocardiogram. However, TEE should be performed as the initial test in certain life-threatening situations or in situations where TTE is likely to be nondiagnostic. Clinical situations in which TEE should be considered as the initial test include [5]:
●Suspected acute aortic pathology (ie, dissection, transsection, intramural hematoma).
●Suspected prosthetic valve dysfunction (thrombus, pannus ingrowth, vegetation, or regurgitation).
●Suspected complications of endocarditis (eg, fistula, abscess).
●Evaluation for left atrial/LAA thrombus in a patient with atrial fibrillation/atrial flutter to facilitate clinical decision-making regarding anticoagulation, cardioversion, or ablation.
●Evaluation of source of embolism in a young (<50 years) patient for whom a TEE would be performed if the TTE was normal.
In 2011 the American College of Cardiology Foundation, in conjunction with numerous professional societies, issued Appropriate Use Criteria for Echocardiography [6]. While appropriate use criteria are not intended to be an exhaustive list of TEE indications, the following indications for TEE were all considered appropriate:
●To diagnose infective endocarditis in patients with moderate or high pretest likelihood (ie, patients with prosthetic valves, certain pathogens). (See "Clinical manifestations and evaluation of adults with suspected left-sided native valve endocarditis".)
●To evaluate for cardiac source of embolus. (See "Echocardiography in detection of cardiac and aortic sources of systemic embolism".)
●To evaluate for suspected acute aortic pathology (ie, dissection). (See "Clinical features and diagnosis of acute aortic dissection", section on 'Diagnosis'.)
●As follow-up to prior TEE when an interval change would result in a change in therapy (eg, resolution of vegetation following antimicrobial therapy).
●To evaluate for cardiac pathology when transthoracic echocardiography is nondiagnostic.
●To facilitate clinical decision-making regarding anticoagulation, cardioversion, or ablation in patients with atrial fibrillation/flutter. (See "Role of echocardiography in atrial fibrillation", section on 'Transesophageal echocardiography'.)
●To provide guidance for noncoronary percutaneous cardiac interventions (eg, placement of closure devices, valvuloplasty, percutaneous valves).
TEE is also used frequently in the evaluation of complex congenital heart disease and may be helpful for evaluating etiologies of hypotension in the intensive care unit.
TEE in critical care — TEE is a useful test that can be performed relatively quickly at the bedside in critically ill patients. Indications for TEE in the critically ill are similar to standard TEE indications in all patients. However, certain scenarios in a critically ill patient may be more quickly and thoroughly investigated with TEE as the initial diagnostic procedure, including [6]:
●Unexplained hypotension.
●Unexplained hypoxemia.
●Suspected complications following a myocardial infarction (ie, acute mitral regurgitation, ventricular septal defect, free wall rupture with cardiac tamponade).
●Uncertain volume status.
●Blunt chest trauma.
●Unexplained hemodynamic instability.
In a review of 83 TEE studies performed in the critical care setting, unexpected findings were observed in 25 percent of patients, resulting in a change in management in 17 percent or a referral for invasive examination in 22 percent. In 16 percent of cases, surgical intervention was performed based on TEE without further examination [7].
PATIENT PREPARATION — For patients undergoing a TEE, the suggested preprocedure assessment, preparation, and monitoring during and after the procedure is similar to gastrointestinal endoscopy. A detailed discussion of this is presented separately. (See "Gastrointestinal endoscopy in adults: Procedural sedation administered by endoscopists".)
SAFETY OF TEE EXAMINATION — Guidelines for TEE competence have been published by the American College of Cardiology and American Heart Association [8]. Although considered moderately invasive and generally performed with conscious sedation, TEE is safe in experienced hands and may be completed in almost all patients when performed by a trained clinician [3,9-11]. (See "Procedural sedation in adults in the emergency department: General considerations, preparation, monitoring, and mitigating complications" and "Gastrointestinal endoscopy in adults: Procedural sedation administered by endoscopists".)
Prior to beginning the TEE, all patients should have a history and physical examination performed, focusing on factors that increase the risk of an adverse outcome (eg, medication allergies, prior difficult intubation or airway problems, odynophagia or dysphagia). Absolute contraindications include the following conditions [12]:
●Perforated viscus
●Esophageal stricture
●Esophageal tumor
●Esophageal perforation/laceration
●Esophageal diverticulum
●Active upper gastrointestinal (GI) bleed
In addition, patients with one or more of the following conditions are at increased risk for complications from TEE (relative contraindications):
●Altered mental status or an uncooperative patient.
●History of radiation to head, neck, or mediastinum.
●History of GI surgery.
●Recent upper GI bleed.
●History of Barrett esophagus.
●Esophageal varices.
●Active esophagitis.
●Active peptic ulcer disease.
●Symptomatic hiatal hernia.
●Tenuous cardiorespiratory status (consider endotracheal intubation prior to TEE for airway protection).
●Surgical interposition of the esophagus.
●History of odynophagia or dysphagia (consider screening endoscopy and/or barium swallow prior to TEE).
●Cervical spine arthritis with reduced range of motion or atlantoaxial joint disease (for example, in patients with Down Syndrome).
●Severe thrombocytopenia (less than 50k), elevated international normalized ratio (greater than 4), or prolonged partial thromboplastin time (>150 seconds).
●Obstructive sleep apnea/airway compromise (consider sedation by anesthesia).
Patients with recent or active esophageal perforation, tear, or hemorrhage should likely not undergo TEE except in extreme situations where the benefits are thought to outweigh the risks. In a patient with a difficult esophageal intubation, the assistance of a trained gastroenterologist or an anesthesiologist, who may directly visualize the glottis with a laryngoscope, can facilitate successful esophageal intubation. Careful attention to posterior pharyngeal anesthesia with topical lidocaine and patient reassurance help to facilitate the esophageal intubation and minimize the degree of sedation that is required. The use of a smaller/pediatric probe should also be considered if initial esophageal intubation is unsuccessful. We avoid transgastric imaging in patients with a history of gastric surgery.
If required, TEE may be performed in patients who are unable to cooperate by using a greater level of sedation and prophylactic endotracheal intubation for airway protection. For situations in which the risk of TEE is high, intracardiac echocardiography may be an alternative study which can provide the needed information.
Serious complications are extremely rare in patients undergoing TEE, having been estimated at less than 1 in 5000 [3,9]. While death during TEE has been rarely reported, complications such as esophageal perforation, gastrointestinal bleeding, pharyngeal hematoma, and methemoglobinemia are more likely to occur but only rarely are fatal.
●Esophageal perforation – There is a very low risk of esophageal perforation. This was illustrated in a study of 10,000 consecutive patients undergoing TEE in which there was one case of hypopharyngeal perforation, two cases of cervical esophageal perforation, and no fatalities [13].
●Gastrointestinal bleeding – An increased risk of bleeding should be considered among patients with thrombocytopenia (platelet count <50 k), those who have received thrombolytic therapy or chronic anticoagulation, and patients with other bleeding diatheses. Patients with esophageal varices and no active or recent variceal bleeding do not appear to be at an increased risk of serious complications from TEE [14-16].
●Pharyngeal hematoma – This upper respiratory tract complication occurs from direct trauma to the posterior pharynx and may result in the acute airway compromise [17].
●Methemoglobinemia – Methemoglobinemia is a rare but potentially life-threatening complication of topical benzocaine and related agents used for posterior pharyngeal anesthesia (eg, two deaths in a review of 132 benzocaine cases reported to the United States Food and Drug Administration) [18]. In a series of over 28,000 TEEs performed at a single center, the incidence of methemoglobinemia was 0.07 percent (1 case per 1499 TEE studies) [19]. Methemoglobinemia should be suspected clinically by the development of cyanosis in the presence of a normal arterial PO2 [20]. Pulse oximetry is inaccurate in monitoring oxygen saturation in the presence of methemoglobinemia, and cannot be used to make the diagnosis. Issues related to the diagnosis and treatment of methemoglobinemia are discussed separately. (See "Methemoglobinemia".)
TEE examination is rarely associated with bacteremia [21]. Professional society guidelines for antibiotic prophylaxis do not recommend prophylaxis for patients undergoing TEE [22,23]. (See "Prevention of endocarditis: Antibiotic prophylaxis and other measures".)
Minor complications are seen in fewer than 1 in 500 examinations [3]. These may include transient bronchospasm, transient hypoxia, nonsustained ventricular tachycardia, transient atrial fibrillation, minimal hemoptysis, or vomiting. Minor complications generally resolve spontaneously without specific treatment following termination of the procedure. A higher rate of complications has been reported in procedures requiring TEE guidance (eg, transcatheter aortic valve implantation, transcatheter mitral valve repair, percutaneous left atrial appendage occlusion), with increasing risk of complications as the duration of the procedure increases [24].
THE NORMAL HEART AND GREAT VESSELS — As with TTE examinations, we believe a complete TEE examination should include imaging of all cardiac chambers, valves, and great vessels, regardless of the indication for the study, as patient condition permits. In 2002, a scientific statement from the American Heart Association made recommendations for standardized segmentation and nomenclature for tomographic imaging of the heart for all modalities (figure 1A-C) [25]. Follow-up TEE studies (eg, to monitor resolution of an atrial appendage thrombus) may be focused.
A standard comprehensive approach to imaging is recommended, but each individual study should be modified to reflect the specific clinical indication. As an example, a patient undergoing TEE examination for evaluation of LAA thrombus should include a careful, focused examination of the appendage in a continuum of imaging planes from 0° to 180°. On the other hand, an examination in a patient with suspected endocarditis should include extensive imaging of all cardiac valves.
This section will describe the normal cardiac anatomy as visualized sequentially during a routine multiplane TEE study. Following intubation of the esophagus, the probe is advanced in most adult patients to a depth of 28 to 30 cm from the incisors, coming to rest in the proximal-to-mid esophagus.
Horizontal plane
Four-chamber view — In the horizontal (0°) imaging plane, a four-chamber view of the heart can be seen, demonstrating the left atrium, mitral valve, left ventricle (LV), right atrium, tricuspid valve, and right ventricle (RV) (image 1). Doppler examination of transmitral inflow and mitral regurgitation may be performed. The RV and LV are frequently foreshortened in this position and the true apex is rarely seen (due to foreshortening and the distance from the imaging probe). Slight withdrawal of the probe permits imaging of the left ventricular outflow tract (LVOT) and aortic valve (image 1).
Mitral valve — The mitral valve should be evaluated in several imaging planes, particularly when mitral valve pathology is suspected. Comprehensive mitral valve imaging is essential for diagnosis and perioperative evaluation. Mitral valve imaging using TEE has excellent correlation with surgical findings. Three-dimensional echocardiography may be helpful for characterization of mitral valve anatomy [26]. (See "Transesophageal echocardiography in the evaluation of mitral valve disease" and "Three-dimensional echocardiography".)
Left atrial appendage — With the transducer positioned in the mid-esophagus, at the base of the heart, the LAA may be examined for thrombus and for decreased contractile function. Use of left-sided contrast may aid in differentiation between normal trabeculae and thrombi. While the LAA length is similar in all imaging planes, its width, accessory lobe visualization and cross-sectional area may vary considerably [27]. (See "Contrast echocardiography: Clinical applications".)
We typically record pulsed Doppler spectra from the mouth of the LAA and left upper pulmonary vein (image 2). Normal LAA flow typically consists of prominent ejection and inflow components after the P wave on the ECG [28]. LAA ejection and inflow velocities are independent of transducer orientation [27]. Among patients in sinus rhythm, LAA ejection velocity is typically >0.5 m/s, with depressed LAA ejection velocity defined as <0.2 m/s [29].
Pulmonary veins — The four major pulmonary veins can readily be identified during the TEE study. The left upper pulmonary vein is best identified in the proximal esophageal level in the horizontal plane, immediately adjacent to the LAA, while the left lower pulmonary vein is often identified with posterior (counterclockwise) rotation of the probe at 110 to 135 degree crystal orientation. The right upper pulmonary vein is easily identified running near parallel with the superior vena cava with the probe rotated anteriorly (clockwise) and the crystal in approximately the 90 degree orientation. Further anterior rotation demonstrates the right lower pulmonary vein.
Similar to the Doppler evaluation of the LAA, pulmonary vein Doppler flow is typically assessed with pulsed Doppler with the sample volume positioned approximately 1 cm within the entrance of the pulmonary vein. Normal pulmonary venous flow in adults is biphasic with a predominant systolic flow [S wave] [30]. With increasing severity of mitral regurgitation, there will be attenuation/decrease in the pulmonary vein S wave and increase in the height of the diastolic flow [D wave]. With severe mitral regurgitation, there is reversal of the expected forward flow in the S wave Doppler spectra. Color Doppler is often helpful to visualize extension of the mitral regurgitation jet into the pulmonary veins.
Pulmonary artery — With the transducer imaging plane in the horizontal (0°) position, the TEE probe is rotated anteriorly and withdrawn slightly to visualize the main pulmonary artery, right main pulmonary artery, and left main pulmonary artery (image 3). The patient may cough or note posterior "irritation" during imaging at this level in the proximal esophagus, and diligent care is required to avoid extubating the TEE probe from the esophagus. The main pulmonary artery is also seen near the study conclusion with the crystal in the 90 degree orientation while examining the aortic arch.
Right and left atria — With the TEE transducer tip in a neutral position, the probe is advanced and rotated anteriorly to evaluate the body of the left atrium, interatrial septum, and the body of the right atrium (image 4). The interatrial septum is evaluated at various crystal orientations with color flow Doppler to assess for evidence of an atrial septal aneurysm, an atrial septal defect or patent foramen ovale. (See "Clinical manifestations and diagnosis of atrial septal defects in adults".)
Further anterior rotation of the probe and intermediate transducer rotation to 40 to 60° permits visualization of the right pulmonary veins (image 5).
Aortic leaflets and aortic root — The probe is rotated slightly posteriorly to visualize the aortic root and aortic valve leaflets, following which the probe is rotated to 30° to 55° to image the aortic valve leaflets in short axis (image 6). Advancement and retraction of the probe in this plane will allow for imaging of the LVOT and ascending aorta, respectively. Color flow Doppler interrogation for aortic regurgitation may also be performed in this orientation.
Vertical plane — In contrast to the multiple maneuvers (anteflexion, retroflexion, retraction, advancement) of the TEE probe and transducer tip required for imaging in the horizontal plane, imaging in the vertical (90°) plane primarily involves simple anterior and posterior rotation of the probe. We begin imaging in the vertical (90°) plane with posterior structures and then rotate the probe anteriorly. The most posterior structure is the coronary sinus and left lower pulmonary vein (image 7). As the probe is slowly rotated anteriorly, we image the mitral valve and two-chamber long axis view of the left atrium and left ventricle (image 7). Color Doppler interrogation of the mitral valve allows identification of central and eccentric jets of mitral regurgitation. (See "Clinical manifestations and diagnosis of chronic mitral regurgitation".)
Further anterior rotation of the probe allows for imaging of the LVOT and aortic valve as well as proximal ascending aorta (image 8).
After imaging the LVOT and aortic valve in the vertical plane, multiplane imaging at 110 to 145° permits enhanced visualization of the LVOT, aortic valve, and the ascending aorta (image 8). Anterior rotation of the probe at this crystal position also results in a favorable orientation for assessment of the tricuspid valve, right atrial appendage, and interatrial septum. Assessment of atrial septal defects or aneurysms, as well as right atrial appendage thrombi, is readily performed. (See "Clinical manifestations and diagnosis of atrial septal defects in adults".)
Returning to the vertical (90°) orientation, further rotation of the probe anteriorly allows for imaging of the pulmonic valve and main pulmonary artery (image 9). With further anterior rotation, the right ventricle, tricuspid valve, and right atrium are well seen (image 9). Continuous-wave Doppler may allow for velocity assessment of the tricuspid regurgitation jet from this orientation.
With further anterior rotation, the superior vena cava, right atrial appendage, body of the right atrium, interatrial septum, and inferior vena cava and Eustachian valve may be seen (the bicaval view) (image 10). Color flow Doppler evaluation of the interatrial septum and/or the injection of agitated saline contrast may allow for identification of an atrial septal defect or patent foramen ovale in this orientation, or such examination may be performed in the 135° orientation previously described. (See "Clinical manifestations and diagnosis of atrial septal defects in adults".)
Finally, anterior rotation of the TEE probe in the vertical plane permits imaging of the right upper pulmonary vein, a vessel important to identify as it is the pulmonary vein most commonly associated with anomalous pulmonary venous return (image 11).
Imaging at the gastroesophageal junction — With the transducer imaging plane in the horizontal (0°) position the TEE probe is advanced toward the gastroesophageal junction (38 to 40 cm) where the right atrial appendage, tricuspid valve, and coronary sinus may be seen (image 12) as the probe approaches the gastroesophageal junction.
During advancement of the probe through the gastroesophageal junction, the patient often experiences a slight epigastric discomfort. Particular diligence is required during probe advancement in patients with a large hiatus hernia to avoid curling of the transducer tip in the distal esophagus. Increased depth penetration is often needed and we customarily change to a lower imaging frequency upon entering the stomach. Anteflexion of the probe permits imaging of the left ventricle in a short axis view at the level of the mitral valve and papillary muscles (image 13). The imaging transducer is then rotated to the vertical (90°) imaging plane to allow for visualization of the inferior and anterior left ventricular walls, mitral leaflets and left atrium (image 13). Slight anterior rotation of the probe will allow for visualization of the LVOT and aortic valve. This view may be especially helpful for Doppler assessment for aortic valve or LVOT gradients.
Further anterior rotation of the probe and rotation of the multiplane imaging transducer to 100 to 120° imaging plane allows for imaging of the right atrium, tricuspid valve, right ventricle, and right ventricular outflow tract (image 14).
Gastric imaging — Advancement of the probe to a length of 42 to 45 cm from the incisors into the fundus of the stomach with maximum anteflexion results in an "apical four or five chamber" equivalent view of the heart (image 15). From this orientation, continuous wave, pulsed, or color flow Doppler examination of the LVOT and aortic valve may be obtained.
Thoracic aorta — After all other images are obtained, attention is turned to the descending thoracic aorta, which is located posteriorly. After identifying the descending thoracic aorta in the horizontal (0°) imaging plane, the probe can be advanced during continuous imaging of the aorta to approximately 45 cm from the incisors or until the aortic lumen is no longer visible (image 16). The probe is then gently retracted during continuous imaging of the descending aorta. Annotations may be made on the screen as to the distance from the incisors at 2 to 3 cm intervals or the specific level of any abnormalities.
Transducer rotation to the vertical (90°) imaging plane allows for longitudinal imaging of the descending thoracic aorta. Color flow Doppler confirms the direction of blood flow (image 16). Further retraction is made with imaging in the horizontal (0°) imaging plane.
As the probe is withdrawn into the proximal esophagus (28 cm from the incisors), the transverse aorta may be seen as the aortic lumen appears to elongate (image 17). The probe is then gently retracted with slight flexion and anterior rotation to view the ascending aorta. Color flow Doppler demonstrates normal aortic flow and, in some cases, flow within the superior vena cava may be seen. Transducer rotation into the vertical (90°) plane at this level may allow for imaging of the pulmonary valve and main pulmonary artery (image 18).
Three-dimensional imaging — Three-dimensional echocardiographic imaging is a useful adjunct for the assessment of ventricular volumes and ejection fraction, evaluation of valvular and other structural cardiac abnormalities, and for guidance of transcatheter structural interventions [31]. For example, three-dimensional imaging can provide more detailed assessment of mitral valve anatomy compared to two-dimensional imaging alone (image 19); this additional characterization is particularly useful when surgical or transcatheter interventions are being planned.
COVID-19 PRECAUTIONS — TEE is considered an aerosol-generating procedure, which poses potential risk for transmission of coronavirus disease 2019 (COVID-19).
Elective TEEs in patients with suspected or known active COVID-19 infection should be postponed. Careful consideration of the risks and benefits of TEE as well as available alternative imaging should be made when patients are suspected or known to have active COVID infection. Appropriate airborne precaution personal protective equipment (PPE) for health care workers during performance of TEE in patients with suspected or known COVID-19 or other airborne infection includes use of fit-tested N95 or other respirators (eg, a powered air-purifying respirator), eye protection (such as a disposable face shield that covers the front and sides of the face), gloves, and a gown. Operating room cap and shoe covers should be worn when the TEE is performed in the operating room setting. While the American Society of Echocardiography recommends a minimum of droplet precaution level PPE (surgical or N95 mask, eye protection, gloves, gown) for performance of TEE in patients without COVID infection [32], some experts recommend the use of airborne precautions regardless of patient COVID status when performing aerosol generating procedures during the COVID pandemic. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Aerosol-generating procedures/treatments'.)
In addition to PPE for caregivers, special attention should be paid to TEE-related equipment to minimize the risk of transmission. Following the procedure, all equipment should be thoroughly wiped down according to local infection control protocols. Sufficient time should be allotted between TEE studies to allow adequate air exchange in the procedure room between cases [33]. Use of high-efficiency particular air (HEPA) filter or other airflow management systems should be considered to reduce the time required to achieve adequate airflow exchange in the room. In COVID-19-positive or suspected-positive patients, in an effort to minimize risk of transmission to the provider, some centers utilize probe covers that are external to the patient so that the operator is not in direct contact with the contaminated probe [34,35].
During TEE in COVID-19-positive or suspected-positive patients, the risk of viral aerosolization may be higher for nonintubated patients due to the potential for coughing. Performing TEE in an already intubated patient may reduce (but not eliminate) the risk of aerosolization [36].
Airway and other aspects of anesthetic management, infection control, and other information on COVID-19 are discussed in detail separately.
●(See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection".)
SUMMARY AND RECOMMENDATIONS
●While both transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) have a variety of clinical indications and applications, in most patients TEE provides superior image quality, particularly for posterior cardiac structures that are nearer to the esophagus and often less well visualized on TTE. Because of its moderately invasive nature, however, TEE is generally reserved for selected indications in which the potential benefits of making a diagnosis outweigh the risks associated with the procedure. For many indications, a TTE study is performed first as it may obviate the need for TEE and/or help to guide the TEE. (See 'Introduction' above.)
●TTE remains the initial test of choice for most patients requiring an echocardiogram. However, TEE should be performed as the initial test in certain life-threatening situations or in situations where TTE is likely to be nondiagnostic, including (see 'Indications for TEE' above):
•Suspected acute aortic pathology (ie, dissection, transsection, intramural hematoma).
•Suspected prosthetic valve dysfunction.
•Suspected complications of endocarditis (eg, fistula, abscess).
•Evaluation for left atrial/left atrial appendage thrombus in a patient with atrial fibrillation/atrial flutter to facilitate clinical decision-making regarding anticoagulation, cardioversion, or ablation.
•Evaluation of source of embolism in a young patient for whom a TEE would be performed if the TTE was normal.
●There are few absolute contraindications to TEE examination (eg, significant esophageal pathology or perforated viscus). However, patients with altered mental status, tenuous cardiorespiratory status, recent or active esophageal tear or hemorrhage, coagulopathies, thrombocytopenia, esophageal stricture, Zenker diverticulum, or severe cervical spine arthritis with reduced range of motion are at increased risk of TEE complications. In patients with a history of gastric surgery, avoidance of transgastric imaging should be considered. (See 'Safety of TEE examination' above.)
●Serious complications are extremely rare in patients undergoing TEE, having been estimated at less than 1 in 5000. While death during TEE has been rarely reported, complications such as gastrointestinal bleeding, esophageal perforation, and methemoglobinemia are more likely to occur but only rarely are fatal. (See 'Safety of TEE examination' above.)
●As with TTE examinations, we believe a complete TEE examination should include imaging of all cardiac chambers, valves and great vessels, regardless of the indication for the study, as patient condition permits. A standard comprehensive approach to imaging is recommended, but each individual study should be modified to reflect the specific clinical indication. (See 'The normal heart and great vessels' above.)
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