EXPERT DOCUMENT

Year : 2022  |  Volume : 6  |  Issue : 3  |  Page : 255-292

Corrected and Republished: Indian Academy of Echocardiography Guidelines for Performance of Transesophageal Echocardiography in Adults

Nitin J Burkule¹, Manish Bansal², Satish C Govind³, R Alagesan⁴, Chandrashekhar K Ponde⁵, Satish K Parashar^6
1 Department of Cardiology, Jupiter Hospital, Thane, Maharashtra, India
² Department of Cardiology, Medanta - The Medicity, Gurugram, Haryana, India
³ Department of Cardiology, Narayana Institute of Cardiac Sciences, Bengaluru, Karnataka, India
⁴ Institute of Cardiology, Madras Medical College, Chennai, Tamil Nadu, India
⁵ Department of Cardiology, Hinduja Hospital, Mumbai, Maharashtra, India
⁶ Department of Cardiology, Metro Hospital, New Delhi, India

Correspondence Address:
Nitin J Burkule
Department of Cardiology, Jupiter Hospital, E. Ex. Highway, Thane - 400 606, Maharashtra
India

Source of Support: None, Conflict of Interest: None

Read associated Erratum: Erratum: Indian Academy of Echocardiography Guidelines for Performance of Transesophageal Echocardiography in Adults with this article

DOI: 10.4103/jiae.jiae_54_22

Transesophageal echocardiography (TEE) has unique advantages over conventional transthoracic echocardiography (TTE). Compared with TTE, TEE generally provides excellent quality images, especially of the posteriorly situated cardiac structures, such as atria, pulmonary veins, mitral valve, and left atrial appendage. TEE also offers a useful alternative to TTE in patients in whom transthoracic acoustic windows are suboptimal. Furthermore, TEE is the most suited imaging modality for use in the operating rooms and cardiac catheterization labs for guiding cardiac surgical or interventional procedures. However, specific training and competence are required for performing TEE successfully, smoothly, safely and with minimum patient discomfort. This document describes the basic principles of TEE examination, including patient selection and preparation, periprocedural monitoring, and probe handling and maneuvers. Commonly recommended views and the techniques to obtain these views are described in detail, followed by evaluation of specific cardiac structures. Finally, the role of TEE in certain specific clinical settings, such as during advanced circulatory support, is also discussed.

Keywords: Atrial septal defect, interventional echocardiography, left atrial appendage, patent foramen ovale, perioperative echocardiography, simulation training

Introduction

Aim of the Document

• Basic principles,
• Patient selection and preparation,
• Periprocedural monitoring,
• Probe handling and maneuvers,
• Commonly recommended views and the techniques to obtain these views,
• Evaluation of certain specific cardiac structures/pathologies,
• Role of TEE in certain specific clinical settings.

Technical and Cognitive Skills Requirement

• Thorough knowledge and understanding of TTE,
• Understanding appropriate indications and absolute contraindications for TEE and the risks of the procedure,
• Knowledge of the procedure of conscious sedation and cardio-respiratory monitoring during the procedure.
• Thorough knowledge of all TEE views and their echocardiographic-anatomic correlation,
• Knowledge of various disease processes with resultant alterations in cardiac structure and function,
• Thorough understanding of cardiac hemodynamics,
• Competence in distinguishing adequate from inadequate TEE examination,
• Basic knowledge of other cardiac imaging modalities such as computed tomography (CT) and cardiac magnetic resonance imaging, which can complement the TEE examination, and
• Competence in preparing a detailed report of a TEE examination.

• Competence in performing complete TTE,
• Dexterity to use all the controls of the TEE probe with one hand and simultaneously maneuvering the probe with the other hand, with good hand-eye coordination,
• Ability to use local anesthesia effectively in the oropharynx and judging its adequacy with gag reflex,
• Competence in using safe and effective conscious sedation,
• Ability to pass the TEE transducer safely into esophagus and stomach and adjusting various probe angulations to get best images and Doppler data,
• Ability to recognize the abnormalities in cardiac structure and function in multiple views,
• Ability to recognize various artifacts,
• Proficiency in performing qualitative and quantitative analysis of the acquired data in a manner that can help the clinician, and
• Ability to safely sterilize the TEE probe.

Probe Hardware

Figure 1: Different parts of a transesophageal echocardiography probe Click here to view

1. Distal tip (transducer lens): It has a round face-plate behind which reside the acoustic lens and an array of packed piezoelectric crystals [two-dimensional (2D) TEE- 128 crystals, 3D TEE- 2500 crystals], resting on the backing material. The piezoelectric crystals when stimulated by electric field emit ultrasonic waves and conversely, upon receiving returning echoes, they generate electrical signals. The frequency of the TEE transducer is between 3.5-7.5MHz for adult probes and 5-10MHz for pediatric probes. The distal tip portion of the probe can be remotely flexed in anteroposterior and side- by-side direction by two control knobs at the handle. Additionally, the phased array of the piezoelectric crystals can be electronically rotated from 0° to 180° to generate multi-angle imaging planes
2. Flexible shaft: It contains the cables carrying electrical impulses and mechanical commands, encased in a synthetic housing providing electrical and water insulation. Any damage to this insulation by bite marks or wear and tear should be inspected periodically. The adult TEE probe has a diameter of 5-6 mm at the shaft and 12 mm at the tip, while the pediatric TEE probe has a diameter of 5-6 mm at the shaft and 10 mm at the tip. These sizes can generally be easily accommodated in the esophagus of adult and pediatric patients, respectively. The probe has markings at 10 cm intervals from the tip, which indicate the depth of insertion. For storage, it is preferable to hang the probe by handle mount in an airy wooden cupboard, just like gastroscopes, rather than winding it up in a suitcase.
3. Handle (controls housing): This is the fusiform and bulky part of the TEE probe with one large wheel to control anteflexion and retroflexion of the tip and one small wheel to control side-by-side flexion. A locking mechanism is available at the inner end of the wheel to fix the position of the tip as desired. It is suggested to always keep the lock in neutral position while inserting, removing, or manipulating the probe in-vivo to avoid internal injury by the flexed probe. The handle also has two closely spaced buttons for 'forward' or 'backward' electronic rotation of the imaging plane from 0° to 180°. Some of the recent probes a have a third button in the middle which can be customized for image acquisition, orthogonal imaging or initiating color Doppler
4. Cable and the connector: They connect the TEE probe to the probe connector socket present on the echocardiography machine.

Cleaning, Disinfection, and Maintenance of the Probe

• Step 1: After the probe is removed from the patient, it should immediately be wiped with lint free gauze. It is then rinsed with running water for 1 minute to remove the body fluids. Do not allow the body fluids to dry which happens when the probe is left unattended after a procedure
• Step 2: The probe is then immersed for 5 minutes in a tray containing a combination of enzymes (e.g., Cidezyme® Xtra from Johnson and Johnson) to completely remove any proteinaceous and lipid materials present. These solutions have cellulase, lipase, protease, amylase, and proprietary enzymes with advanced proteolytic action. Hence, overexposure may degrade the outer covering of the probe shaft. It is preferable that the person doing the sterilization should wear protective clothing in the form of a disposable cap, glove, plastic apron, eye protection and mask
• Step 3: The probe is then rinsed again with clean running water and wiped dry using lint free gauze. This is to remove the water which may dilute the concentration of the disinfectant and to also remove any debri
• Step 4: The connector can be plugged into an electrical leakage testing unit before high-level disinfection
• Step 5: The probe is left inside the high-level disinfectant solution of recommended concentration. Glutaraldehyde 2% solution, which is available as Cidex®, is the commonly used disinfectant solution. It kills all the bacteria, viruses and spores in 20 minutes. In United Kingdom, this substance is banned. Ortho-phthalaldehide 0.55% solution (HOSPAL-OPA®) is alternatively used, and the probe is kept immersed for 12 minutes. The minimum required concentration can be checked by using test strips. The solution is usually changed once in 14 days and earlier if it fails during the test
• Step 6: The disinfected probe should be rinsed with clean water thrice, for one minute duration each time, to remove any disinfectant
• Step 7: The probe is then wiped dry and kept inside a disposable sterile cover ready for use in the next patient
• Step 8: The probe is then stored in a cabinet hanging vertically down [Figure 2], the cabinet should be dry and in a high-efficiency particulate absorbing (HEPA) filter clean space
• Step 9: The probe must be carefully transported inside and outside the hospital by keeping it in a carrying case
• Step 10: The metallic part of the probe and connector's external surface may be sprayed and wiped clean with 70% isopropyl alcohol or using sanitary wipes soaked in alcohol. Care should be taken to ensure that no liquid enters any unsealed joints near the control knobs. Entry of liquids may produce corrosion and electrical damage.

Figure 2: Probe storage cabinet Click here to view

Patient Selection

1. If TTE is non-diagnostic due to poor acoustic window despite the use of ultrasound contrast, or when more critical information is required about posterior cardiac structures
2. Infective endocarditis-



1. In patients with clinical suspicion of infective endocarditis, especially when TTE is negative. TEE has higher resolution to diagnose smaller vegetations. There is generally a low threshold to perform TEE in cases of clinically suspected prosthetic valve/conduit or pacemaker endocarditis
2. In acutely ill patients with infective endocarditis, there is a low threshold to perform TEE to pick up early para-valvular abscesses, valve perforations, prosthetic valve dehiscence or other structural damage caused by the infection
3. Surveillance TEE is indicated in infective endocarditis if there is no response to treatment or deterioration in clinical condition.



3. To exclude LA/LAA clot in patients with atrial fibrillation (AF) who are scheduled to undergo electrical cardioversion or radiofrequency (RF) ablation
4. Valve lesions-



1. In mitral or aortic valve regurgitation, to assess the mechanism of regurgitation and feasibility of repair
2. In mitral stenosis (MS), to diagnose LAA clot before balloon mitral valvotomy or when the patient presents with a cardioembolic event
3. In aortic stenosis (AS), TEE may be useful for diagnosis of subaortic membrane, direct planimetry of aortic valve area, accurate measurement of left ventricular (LV) outflow tract (LVOT) diameter or cross-sectional area, and the size of aortic sinuses or ascending aort
4. In patients with prosthetic valve dysfunction, especially in case of mitral prosthetic valve, TEE invariably provides incremental information over TTE and fluoroscopy by improved visualization of thrombus, pannus, paravalvular regurgitation.



5. In cryptogenic stroke, TEE is essential to exclude right-to-left shunt across patent foramen ovale (PFO) (aided by saline bubble contrast with Valsalva maneuver), to visualize mobile atheromas in the arch of aorta and to detect other unsuspected cardiac sources of embolism^[15]
6. Congenital heart diseases-



1. TEE is useful in adults with TTE evidence of unexplained RA and right ventricular (RV) dilatation with or without pulmonary hypertension (PH). In such cases, TEE helps to diagnose pre-tricuspid shunts such as sinus venosus atrial septal defect (ASD) and partial anomalous connection of pulmonary veins. In adult patients with TTE diagnosis of ostium secundum ASD, TEE is frequently performed for assessing suitability for device closure. Similarly, in case of suspected primary PH, TEE is frequently performed before planning cardiac catheterization
2. TEE is often useful for evaluation of RV outflow tract/LVOT stenosis, sub-valvular and valvular pulmonary stenosis/ AS, and the function of conduits in adult patients with congenital heart disease.



7. In cases of cardiac masses, TEE is frequently performed if TTE is unable to delineate the attachment, infiltration, spatial extension, and hemodynamic impact of the mass
8. TEE is immensely useful in the cardiac catheterization lab for guiding various interventional procedures such as device closures (ASD, ventricular septal defect, ruptured sinus of Valsalva aneurysm, paravalvular regurgitation, etc.), percutaneous valve implantation or repair, interatrial septal puncture, RF ablation of pulmonary veins, LAA closure, and insertion of ventricular assist devices (VAD) and extracorporeal membrane oxygenation cannulas
9. Role in the operating room-



1. TEE has an important role in the cardiac operating room, especially during the surgery for valvular or congenital heart diseases.^{[16],[17],[18]} After induction, a quick TEE examination re-confirms the diagnostic findings and often provides additional information to guide the surgical planning. After release of the cross-clamp, once the ventricles start ejecting and the weaning from the cardiopulmonary bypass starts, a quick assessment of LV preload, ventricular recovery and intracardiac air bubbles can be performed with TEE. After achieving adequate systemic blood pressure (BP), adequacy of structural repair or functioning of the implanted valves can be thoroughly assessed. The crucial decision at this moment regarding the need for a second run of cardiopulmonary bypass for inadequate repair heavily depends on meticulously gathered semi-quantitative TEE data^[16]
2. Even during the non-cardiac surgeries, TEE may be required in case of unexplained hypotension, hypoxia, or hemodynamic instability. In such circumstances, TEE can provide a quick assessment of ventricular function, volume status and intracardiac hemodynamics.



10. In hemodynamically unstable, post myocardial infarction or post-operative patients in cardiac ICU, TEE is indicated when the cardiac cause of deterioration is suspected and TTE is either non-diagnostic or not feasible due to the presence of chest dressings and drainage tubes and/or unfavorable patient position because of mechanical ventilation. TEE is useful in recognizing new-onset or worsening LV systolic dysfunction, aortic dissection, LA thrombus, ruptured papillary muscle, cardiac-aortic source of embolism, intracardiac vegetation, acute native or prosthetic valve dysfunction, which are frequently missed during TTE in such patients^[19],[20]
11. In patients with severe chest pain with normal cardiac biomarkers and non-diagnostic electrocardiogram (ECG), and with suspected acute aortic syndrome, TEE may be considered if cardiac CT is not immediately available
12. TEE is more sensitive in detecting intrapulmonary shunt in patients with cirrhosis of liver. The detection rate for intrapulmonary shunt in patients with PaO2 <80 mmHg or dyspnea is 56% and 50%, respectively, with TEE and 33% and 25% with TTE.^[21]

1. Non-diagnostic TTE
2. Surveillance of LA thrombus or valvular vegetation for resolution on optimal treatment, and for modifying or stopping therapy
3. For guiding transcatheter device therapy
4. Acute aortic syndrome
5. Evaluation for valve repair surgery
6. Diagnosis of infective endocarditis when pre-test probability is moderate to high
7. Evaluation of cryptogenic or suspected cardioembolic stroke
8. Patients with AF scheduled to undergo electrical cardioversion or RF ablation.

1. After good quality TTE with diagnostic information optimal for therapeutic decision-making
2. Surveillance of LA clot or valvular vegetation on optimal treatment when no change in treatment is anticipated
3. Asymptomatic patient after pulmonary vein isolation by RF ablation
4. Diagnosis of infective endocarditis when pre-test probability is low
5. Evaluation of cardioembolic stroke with known source on TTE
6. AF patients on anticoagulation not considered for electrical cardioversion.

1. Recent oropharyngeal or esophageal surgery
2. Obstructive pathology of pharynx or esophagus like neoplasm or stricture
3. Suspected esophageal perforation or traumatic injury
4. Diverticulum of esophagus
5. Active bleeding from esophageal ulcer or varices.

1. Loose teeth or gum injury
2. Agitated and uncooperative or delirious patient
3. Inability to open mouth widely
4. History of radiation to head, neck, or mediastinum
5. History of Barrett's esophagus
6. Non-bleeding ulcers or grade 1 or 2 esophageal varices with no recent variceal bleeding- TEE can be performed safely, avoiding lower esophageal and transgastric views^[23]
7. Hiatus hernia
8. History of odynophagia or dysphagia
9. Cervical spine arthritis or instability
10. Prolonged partial thromboplastin time or thrombocytopenia
11. Bleeding diatheses but no active bleeding
12. Obstructive sleep apnea/airway compromise during intravenous (IV) sedation.

Patient Set-up, Anesthesia, Intra-procedure Monitoring Considerations

• Non-sedated and lightly sedated patients will not be able to communicate verbally during TEE examination due to esophageal intubation. Therefore, the patients should be instructed in advance to use hand gestures to communicate the level of discomfort (tolerable or intolerable)
• The operator and the assistant should remain vigilant about obvious warning signs such as facial expression of discomfort, cyanosis of lips and fingers, cold clammy extremities, fast and thready pulse or changes in breathing rate and pattern
• The pulse oximeter should be closely watched for any desaturation. Supplemental oxygen should immediately be provided through nasal cannula in case of fall in the saturation or hypoventilation in a deeply sedated patient. The test should be terminated if the saturation does not improve or worsens
• The heart rate and rhythm are automatically monitored by the echocardiography machine (provided ECG cable is connected) and are displayed on the monitor. One should watch for significant sinus tachycardia, bradycardia or arrhythmias which may result in hemodynamic instability
• For ICU patients or those receiving IV sedation, non-invasive BP monitoring with cuff inflation time set at every 5 minutes at least is mandatory. Those on naso-gastric tube should have it aspirated and preferably, removed before the TEE probe is inserted
• Frequent suctioning of the oropharyngeal secretions should be performed if TEE is being performed under IV sedation.

1. Lung aspiration
2. Tooth (native or implanted) dislocation and displacement into airway
3. Pharyngeal hematoma causing upper airway compromise^[34]
4. Laryngeal injury due to probe entering the trachea
5. Esophageal perforation or Mallory-Weiss tear
6. Mediastinitis due to unsuspected perforation at cricopharyngeal junction or in the esophagus
7. Bleeding from upper gastroesophageal ulcers or varices
8. Methemoglobinemia- The incidence of methemoglobinemia due to the local anesthetic spray is low (1 case per 1499) and has a good outcome if promptly recognized (cyanosis, fall in saturation with normal PaO2) and treated with IV methylene blue (1% solution, 1 to 2 mg/kg IV slowly over 5 min). Clinical factors associated with the development of methemoglobinemia are sepsis, anemia, and hospitalization.^[35]

1. Mucosal laceration with streaky bleeding while coughing or spitting
2. Dysphagia, odynophagia
3. Sore throat
4. Vomiting
5. Bronchospasm, laryngospasm
6. Transient ventricular arrhythmia, AF
7. Heart failure
8. Dislodgement of endotracheal tube in patients on mechanical ventilation
9. Dental injury.

Technique of Probe Insertion

Technical Aspects of Probe Manipulation and Image Display

Figure 3: Orientation of cardiac structures in relation to image display on the monitor. (a) Imaging plane horizontal, (b) Imaging plane vertical Click here to view

1. Advancing and withdrawing the probe ('in' and 'out' motion)


The TEE probe can be gently 'advanced' or 'pushed in' or can be gradually 'withdrawn' or 'pulled out'. If the imaging plane is in horizontal orientation, advancing or withdrawing the probe will transect the heart at different levels in craniocaudal direction [Figure 4]. Conversely, with vertically oriented imaging planes, this movement will result in greater visualization of more caudal or cranial structures [Figure 4]. If a more cranial structure (displayed towards the right margin of the image sector) needs to be visualized, then the probe should be gently withdrawn. In contrast, if the structures at the left margin of the image sector (i.e., more caudal structures) need to be evaluated, then the probe should be gently advanced


2. Clockwise and anticlockwise torque


The TEE probe can be gently and gradually rotated (torqued) either clockwise or anticlockwise (assuming the patient's face to represent the clock face). Small degrees of torque adjustment can be done with the hand holding the shaft of the probe. However, large angle of torquing is achieved more easily by rotating the handle of the TEE probe

The clockwise torque of the TEE probe turns the imaging plane towards right-sided cardiac structures, while the anticlockwise torque turns the imaging plane towards the left-sided structures. If the imaging plane is oriented vertically, then torquing the probe will move the imaging plane sideways, transecting the heart vertically at different positions [Figure 5]. However, if the imaging plane is horizontal, then anticlockwise torque of the probe brings the left-sided structures (i.e., those displayed towards the right margin of the image sector) towards the center of the display [Figure 5]. Conversely, a clockwise torque results in the right-sided cardiac structures (those displayed towards the left margin of the image sector) coming towards the center of the image display


3. Electronic rotation of the imaging plane


The TEE imaging plane can be electronically rotated, using the buttons on the probe handle (and in some machines, using the controls on the monitor), around an imaginary anteroposterior axis (with respect to the patient's chest). The plane rotates by each degree unit, in anti-clockwise direction (when viewed from the front of the chest), starting from 0° (horizontal or axial plane) all the way through 30°-60° [short-axis (SAX) plane], 90° (vertical or sagittal plane), 120°-135° (long-axis plane) to 180° (horizontal, mirror image) [Figure 6]. The rotation angle and location of the plane are shown on the monitor in the form of a dial displayed at the left or right upper corner of the image display


4. Flexion of the distal tip


Two separate wheel-like knobs are situated on the control handle using which the distal end of the TEE probe can be flexed antero-posteriorly (bigger wheel) or rightward or leftward (smaller wheel) [Figure 7]. The operator should be aware that excessive movements can cause discomfort to the patients

Anteflexion: Anterior flexion of the TEE probe bends the tip forwards, tilting the transducer lens cranially. If there are air bubbles trapped in front of the transducer lens, the gentle anteflexion helps in achieving good contact between transducer lens and anterior esophageal wall, thereby improving the image quality. For transgastric views, anteflexion is a rule, to achieve good contact between the transducer lens and the roof of the fundus to get adequate trans-diaphragmatic views. The horizontal imaging plane gets tilted cranially by anteflexion. This maneuver is particularly useful for obtaining outflow tract view, from transgastric SAX views. This outflow tract view allows parallel alignment of the Doppler beam with the blood flow and is ideal for measuring gradients

Retroflexion: Retroflexion of the TEE probe bends the tip backwards and tilts the transducer lens caudally. The horizontal imaging plane gets tilted caudally by retroflexion. This maneuver is particularly useful for imaging LV apex in the mid-esophageal (ME) 4-chamber view. In the lower esophageal view, the inferior vena cava (IVC) margin of ASD invariably falls in the apical clutter of the image sector. The retroflexion maneuver is useful to move gastroesophageal junction away from the base of the heart, thereby moving the IVC margin of the ASD out of the apical clutter

Side-by-side flexion: This maneuver used to be helpful in the era of monoplane and biplane TEE to get intermediate angulations from horizontal or vertical imaging planes. Currently, with the availability of multiplane TEE, use of sideways flexion is limited but may sometimes be necessary during transgastric imaging, especially when right or left side structures are being imaged.

Figure 4: The effect of advancing or withdrawing the probe on the image display. (a) Horizonal imaging plane, (b) vertical imaging plane. AV: Aortic valve, CS: Coronary sinus, IVC: Inferior vena cava, SVC: Superior vena cava Click here to view

Figure 5: The effect of clockwise and anticlockwise rotation or torque of the probe on the image display. (a) Horizonal imaging plane, (b) Vertical imaging plane. LAA: Left atrial appendage, LV: Left ventricle, RV: Right ventricle Click here to view

Figure 6: Orientation of the imaging plane at different multi-plane angles Click here to view

Figure 7: Anteflexion, retroflexion and sideways flexion of the probe Click here to view

Imaging Windows

Figure 8: Standard imaging windows. Reproduced with permission from: Hahn RT, Abraham T, Adams MS, Bruce CJ, Glas KE, Lang RM, et al. Guidelines for performing a comprehensive transesophageal echocardiographic examination: recommendations from the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists. J Am Soc Echocardiogr 2013;26:921-64 Click here to view

1. ME window: The ME view is at the level of cardiac chambers. It is the most utilized view with maximum information. This view is useful for detailed evaluation of the following structures- LA cavity, LAA, interatrial septum, all the four pulmonary veins, multiplanar imaging of MV apparatus, multiplanar imaging of aortic valve and aortic root, LV in all the three long-axis views, RV inflow and outflow tract, RA cavity, in-flow portions of SVC and IVC, tricuspid valve (TV), ascending aorta up to the level of posterior crossing of right pulmonary artery
2. Lower esophageal window: The lower esophageal view is at the level of gastroesophageal junction. This view is useful for following structures- additional evaluation of the TV (especially for acquisition of 3D data set of the TV), evaluation of coronary sinus, visualization of upper hepatic portion of IVC and hepatic vein tributary, IVC margin of the ASD, Eustachian valve, distal part of descending thoracic aorta, and the evaluation of pleural spaces for any effusion
3. Transgastric window: The transgastric views are acquired by gradually advancing the probe from gastroesophageal junction to the distal part of the fundus and intermittently ante-flexing the tip at different levels (care should be taken to avoid advancing or withdrawing the probe with its tip anteflexed to avoid mucosal injury). This window provides three SAX images of the LV from base to apex. These SAX images are helpful in wall motion analysis of all the 16 segments of the LV. The basal SAX view also shows en face view of the MV orifice. Anteflexion from apical position allows visualization of LVOT and measurement of LV outflow velocity and gradient. The long-axis views from transgastric window are useful for assessing LV inflow and outflow tract. The long-axis views are also useful for evaluation of RV inflow and outflow tracts
4. Upper esophageal window: The upper esophageal view is useful for detailed evaluation of following structures- main pulmonary artery, right pulmonary artery, SVC, right superior pulmonary vein, descending thoracic aorta, entire arch of aorta and origins of the arch branches.

• Upper esophageal window- 20 to 22 cm
• ME window- 28 to 35 cm
• Lower esophageal (gastroesophageal junction) window- 38 to 40 cm
• Deep transgastric (fundus) window- 42 to 45 cm.

General Principles of Imaging

• The study goal should be to increase the diagnostic yield in a time-efficient manner, with least discomfort and risk to the patient
• Minimum manipulation of TEE probe by sequential selection of TEE views and TEE windows. The TEE probe 'in and out' or 'torquing' movements should be done gently and in gradual increments
• Visualize the expected pathological structure first and perform less important imaging later. This can salvage the study in case of premature termination of the test due to patient discomfort or instability
• Focus on one structure of interest at a time to avoid missing inconspicuous pathologies
• The transgastric views need extreme anteflexion and are prone to cause discomfort to the conscious patients. These views should be obtained in conscious patients only if additional information, not available on TTE or from esophageal TEE windows, is required
• The Valsalva maneuver, used for detecting right-to-left shunt across PFO using saline bubble contrast, requires patient's effort and cooperation. It should be performed as the penultimate step
• High esophageal arch imaging should be performed at the last as it causes patient discomfort and often leads to termination of the test.

• Positioning the structure of interest in the centre of the imaging sector,
• Careful setting of probe frequency, focus position, gain and compression,
• A thorough multiplanar electronic sweep of imaging plane from 0°-120° at gradual (5°-10°) increment to evaluate the pathology found,
• To image the structure thoroughly, perform a gentle “clockwise-anticlockwise torque” and a gentle “inward-outward push-pull” of TEE probe at every imaging plane (at approximately 0°, 30°, 60°, 90°, and 120°),
• Color flow mapping and pulsed-wave (PW) or continuous-wave (CW) Doppler interrogation at appropriate locations, and
• Use of tissue Doppler imaging and 3D echocardiography whenever required.

General Workflow of Comprehensive Imaging and Main Views

Figure 9: Mid-esophageal 0° five-chamber view. LA: Left atrium, LV: Left ventricle, RV: Right ventricle Click here to view

Figure 10: Mid-esophageal 0° four-chamber view. LA: Left atrium, LV: Left ventricle, RV: Right ventricle Click here to view

Figure 11: Mid-esophageal bi-commissural view. LA: Left atrium, LV: Left ventricle Click here to view

Figure 12: Mid-esophageal two-chamber view. LA: Left atrium, LV: Left ventricle Click here to view

Figure 13: Mid-esophageal long-axis view. LA: Left atrium, LV: Left ventricle Click here to view

Figure 14: Mid-esophageal zoomed left ventricular inflow-outflow view. LA: Left atrium, LV: Left ventricle Click here to view

Figure 15: Mid-esophageal ascending aorta long-axis with right pulmonary artery short-axis view. LA: Left atrium, RPA: Right pulmonary artery Click here to view

Figure 16: Upper-esophageal 0° main and right pulmonary artery long-axis view. Ao: Ascending aorta, MPA: Main pulmonary artery, RPA: Right pulmonary artery Click here to view

Figure 17: Upper-esophageal 0° right superior pulmonary vein long-axis and superior vena cava short-axis view. Ao: Ascending aorta, LA: Left atrium, RSPV: Right superior pulmonary vein, SVC: Superior vena cava Click here to view

Figure 18: Upper-esophageal 30°–60° right superior and inferior pulmonary vein view. RIPV: Right inferior pulmonary vein, RSPV: Right superior pulmonary vein Click here to view

Figure 19: Upper-esophageal 0° right atrial appendage, superior vena cava and ascending aorta view. Ao: Ascending aorta, LA: Left atrium, RAA: Right atrial appendage, SVC: Superior vena cava Click here to view

Figure 20: Mid-esophageal 60° aortic valve short-axis and right ventricular inflow-outflow view. LA: Left atrium, MPA: Main pulmonary artery, RA: Right atrium, RV: Right ventricle Click here to view

Figure 21: Mid-esophageal 70°–90° inferior vena cava right atrial junction view. IVC: Inferior vena cava, LA: Left atrium, RA: Right atrium Click here to view

Figure 22: Mid-esophageal 90°-110° superior vena cava right atrial junction view. LA: Left atrium, RA: Right atrium, RAA: Right atrial appendage, RPA: Right pulmonary artery, SVC: Superior vena cava Click here to view

Figure 23: Mid-esophageal 60° left atrial appendage left superior pulmonary vein view. LA: Left atrium, LAA: Left atrial appendage, LSPV: Left superior pulmonary vein Click here to view

Figure 24: Mid-esophageal 120° left superior and inferior pulmonary vein view. LIPV: Left inferior pulmonary vein, LSPV: Left superior pulmonary vein Click here to view

Figure 25: Lower-esophageal coronary sinus view. LV: Left ventricle, RA: Right atrium, RV: Right ventricle Click here to view

Figure 26: Lower-esophageal pleural spaces Click here to view

Figure 27: Transgastric basal left ventricular short-axis view. AML: Anterior mitral leaflet, PML: Posterior mitral leaflet Click here to view

Figure 28: Transgastric mid left ventricular short-axis view Click here to view

Figure 29: Deep transgastric left ventricular apical short-axis view Click here to view

Figure 30: Deep transgastric left ventricular short-axis outflow views. Upper panel- right ventricular outflow view; lower panel- left ventricular outflow view. LA: Left atrium, RVOT: Right ventricular outflow tract Click here to view

Figure 31: Transgastric left ventricular long-axis two-chamber view. LA: Left atrium, LV: Left ventricle Click here to view

Figure 32: Transgastric right ventricular inflow long-axis view. RA: Right atrium, RV: Right ventricle Click here to view

Figure 33: Transgastric left ventricular long-axis inflow-outflow view. LA: Left atrium, LV: Left ventricle Click here to view

Figure 34: Mid-esophageal descending aorta short-axis (upper panel) and long-axis (lower panel) views Click here to view

Figure 35: Upper esophageal aortic arch short- and long-axis views with branch vessels. LCCA: Left common carotid artery, LSCA: Left subclavian artery Click here to view

Figure 36: Simultaneous biplane imaging Click here to view

Table 1: Recommended transesophageal echocardiographic views, cardiac structures visualized and the techniques for obtaining those views Click here to view

Principles of Three-dimensional Data Set Acquisition

1. While planning the zoomed capture of a structure, select the best TEE imaging plane showing the structure, pathological highlight, and an adjacent important anatomical landmark. For example, for MV 3D capture, 120° is a good plane to begin with, with the addition of aortic root as an anatomical landmark. Thereafter, adjust the zoom window in multiplane mode or simultaneous biplane to ensure that the entire structure is included in the 3D dataset. A real-time multi-slice mode at this juncture to ensure that full circumferential extent is included may help
2. Adjust the biplane zoom window to minimum size but encompassing the entire structure and accompanying anatomical landmark. Keep the gains setting to 60% and uniform throughout the field. Train the patient beforehand to hold breath for 6-8 seconds and to follow operator's instructions for breath hold and release. With the operator keeping his hand holding the probe shaft steady and the patient (when conscious and co-operating) holding the breath, try to choose maximum number of cardiac cycles^[6],[7] to acquire multi-beat 3D dataset without stitch artefacts. The stitch artefacts can be examined in the image pane which is perpendicular to the primary view
3. Acquire multiple datasets by changing the viewing angle while using the same principle as described above.

Figure 37: Postprocessing of three-dimensional echocardiographic dataset. (a) Auto dissection of three-dimensional data set into 3 orthogonal planes. The yellow, white and green dotted lines show the plane orientation and yellow, white and green corner square markings show the two-dimensional image in the corresponding plane; (b) For viewing the mitral valve en face, the green plane is chosen as the viewing plane and the yellow and white planes are the orthogonal planes. The orthogonal planes are steered to dissect the mitral valve longitudinally through the center of the mitral orifice. The viewing plane (green) is then steered to be perpendicular to the crosshair formed by the orthogonal planes (yellow and white) so that it is perfectly parallel to the mitral valve. By using “flip crop” and axial “z” rotation of the viewing plane, the prescribed surgeon's view can be shown Click here to view

Focused Imaging of Specific Cardiac Structures

Figure 38: Three-dimensional transesophageal echocardiographic visualization of the mitral valve from the left atrial side (i.e., the “surgeon's view”). A1, A2, A3, P1, P2, and P3 are scallops of anterior and posterior mitral valve leaflets, respectively Click here to view

Figure 39: Two-dimensional transesophageal echocardiographic visualization of the mitral valve in different views. A1, A2, A3, P1, P2, and P3 are scallops of anterior and posterior mitral valve leaflets, respectively. Ao: Aorta, LC: Lateral commissure, MC: Medial commissure, ME: Mid-esophageal Click here to view

1. At ME 0-30° viewing plane (four-chamber view), anterior and posterior mitral leaflets (AML and PML, respectively) are displayed in observer's left to right orientation on the monitor. The AML is formed by A3-A2 scallops in base-to-free edge direction. The PML is formed by mainly P2 or P1-P2 scallops in base-to-free edge direction
2. From ME 0° viewing plane, if the TEE probe is gradually withdrawn to develop five-chamber view, A1 and P1 scallops can be visualized and further withdrawing the probe brings the anterolateral commissure of the MV in the view [Figure 40]. This maneuver is useful for analyzing fusion, calcification and commissural regurgitation involving the anterolateral commissure. Conversely, advancing the transducer visualizes A3 and P3 scallops [Figure 40]
3. At ME 45°-75° viewing plane showing the bi-commissural view, the medial and lateral commissures are displayed in observer's left to right orientation on the monitor. Three MV segments are visualized in this view viz. P3-A2-P1 (sometimes P3-A3A2A1-P1), displayed in left to right direction on the monitor. From this view, with clockwise torque (rightward) the imaging plane successfully cuts through entire AML, from free edge to base to aorto-mitral inter-valvular fibrosa. Similarly, with anti-clockwise torque (leftward), entire PML can be visualized from free edge to base [Figure 40]
4. At ME 90° viewing plane, PML-AML are displayed in observer's left to right orientation on the monitor. The AML is formed by A1-A2 scallops in base-to-free edge direction. The PML is formed by mainly P3 or P3-P2 junction. From this view, with clockwise torque (rightward), the imaging plane successively cuts through the posteromedial commissure. This maneuver is useful for analyzing fusion, calcification and commissural regurgitation involving the posteromedial commissure
5. At ME 120°-135° viewing plane, PML-AML are displayed in observer's left to right orientation on the monitor. The AML is formed by A2 and PML by P2, with the imaging plane passing through the center of the MV orifice. With clockwise (rightward) and anti-clockwise (leftward) torque, the imaging plane moves sideways, cutting through remaining parts of the leaflets and the medial and lateral commissures, respectively
6. At every viewing plane, color Doppler interrogation (and if needed PW or CW Doppler) can be performed to visualize the mitral regurgitation (MR) jets. The MR jets due to AML pathology are generally directed posteriorly, whereas jets due to PML pathology are directed anteriorly. The regurgitant jets due to lateral commissural pathology are directed medially towards interatrial septum and those due to medial commissural pathology are directed laterally towards LAA. In case of non-coaptation of the central part of the MV leaflets or PML clefts, the MR jets are generally directed centrally towards the LA roof.

Figure 40: Upper panel shows mitral valve structures visualized as the transesophageal echocardiography probe is advanced or withdrawn from the mid-esophageal 0° four-chamber view. The lower panel shows the effect of clockwise and counterclockwise rotation of the probe in bi-commissural view. Reproduced from: Chen C, Okoh A, Garg A, Russo M. Catheter-based mitral intervention imaging and procedural TEE; November 2020. Available from: https://www.ctsnet.org/article/catheter-based-mitral-intervention-imaging-and-procedural-tee. [Last accessed on 2021 Jul 09] Click here to view

1. Carpentier type II (A2/P2 prolapse/flail) MR, or
2. Secondary MR

• Non-rheumatic valve/no infective endocarditis
• Leak at A2-P2
• Grade III/IV MR
• Single/dominant central jet
• No calcium at the grasping site
• In case of secondary MR: leaflet coaptation depth <11 mm, coaptation length >2 mm [Figure 41]
• In case of Carpentier type II (A2/P2 prolapse/flail) MR: nontethered PML >10 mm, flail width <15 mm, flail gap <10 mm [Figure 42]
• MV area (MVA) >4 cm² on 3D TEE
• Baseline MV mean gradient <3 mmHg
• LV cavity size <65 mm
• Trans-septal crossing height from mitral annulus >4 cm.

Figure 41: Preferred anatomic criteria for transcatheter mitral valve edge-to-edge repair in secondary mitral regurgitation Click here to view

Figure 42: Selection criteria for transcatheter mitral valve edge-to-edge repair in degenerative mitral regurgitation Click here to view

• Carpentier IIIA abnormality (i.e., rheumatic heart disease)
• Infective endocarditis
• LA/LAA clot
• Calcification of leaflets at grasping area
• MV mean gradient >5 mmHg
• MVA < 3 cm² on 3D TEE
• Severe RV dysfunction and PH unrelated to MR
• ASD closure device
• IVC thrombosis.

• Define the leaflet target,
• Trans-septal puncture and safe steering of steerable guiding catheter (SGC) and clip delivery system (CDS) in the LA,
• Proper clip alignment,
• Grasping the leaflets,
• Assessment of MR reduction, and
• Exclusion of significant MS and assessment of interatrial shunt.

• The trans-septal puncture should be performed through the posterior-mid aspect of the fossa. This is confirmed by simultaneous biplane imaging at approximately 45° for anteroposterior orientation (puncture site posteriorly) and 90° for superior-inferior orientation (puncture site in mid-fossa) [Figure 43] and [Video 29]
• At the same time, the puncture height should be at least 4-4.5 cm above the mitral annulus; this is confirmed in 2D 4-chamber view (0°-20°) [Figure 43]. Less than 4 cm may be acceptable when coaptation is deeper in the LV, whereas >4.5 cm is often necessary when flail leaflet is the underlying pathology
• Sharp tenting of the interatrial septum should be seen in both 45° and 90° views before puncturing the septum
• Following septal puncture, a guidewire is positioned in the left upper pulmonary vein
• SGC is introduced into the LA, under fluoroscopy and TEE guidance in 45° SAX view and live 3D imaging. CDS is introduced subsequently in the same manner. It is important to ensure that the SGC and CDS tips are away from the surrounding tissues
• The CDS is flexed towards the MV, while the device tip is followed in the 45° SAX view and four-chamber view.

Figure 43: Transseptal puncture for transcatheter mitral valve edge-to-edge repair. (a) Biplane imaging to ensure that the puncture is done in mid-fossa (left image) and away from the aortic valve (right image). (b) The puncture height (orange arrow) should be 4–4.5 cm above the mitral annular plane. Yellow arrows point to the site of septal tenting just prior to the puncture. IVC: Inferior vena cava, SVC: Superior vena cava Click here to view

• Simultaneous biplane imaging with bi-commissural view (60°) for medial-lateral orientation and the LVOT view (135°-150°) for anteroposterior orientation [Figure 44] and [Video 30], and
• 3D TEE LA aspect en face MV view [Figure 44] and [Video 31] or the transgastric basal SAX view for aligning the clip perpendicular to the coaptation line.

Figure 44: Aligning the clip in relation to the mitral valve. (a) Biplane imaging is used to simultaneously orient the clip in medial-lateral direction (bi-commissural view, left image) as well as anteroposterior direction (LVOT view). (b) Three-dimensional en face view is used for orientating the clip perpendicular to the coaptation line. LVOT- left ventricular outflow tract Click here to view

Figure 45: Aligning the clip once it has been advanced into the left ventricle. The principles of imaging are same as in Figure 44. LVOT: Left ventricular outflow tract Click here to view

Figure 46: Grasping of the mitral valve leaflets is performed in the LVOT view. AML: Anterior mitral leaflet, LVOT: Left ventricular outflow tract, PML: Posterior mitral leaflet Click here to view

• Both leaflets are captured and are fully inserted to the base of 'V' between gripper and arms,
• There is non-existent or limited leaflet motion relative to the clip arms,
• On the medial and lateral sides of the clip, the leaflets enter at the same level,
• Clip arms are perpendicular to the line of coaptation, and the clip is not biased towards the anterior or posterior leaflet, and
• There is satisfactory reduction of MR.

• MR jet size in 2D TEE color-flow Doppler in all the standard views and 3D TEE color-flow Doppler,
• Pulmonary vein flow pattern (no systolic flow reversal with restoration of systolic forward flow or improvement in systolic forward flow from baseline), and
• Increase in LVOT velocity/LV stroke volume (quantified from the 2D TEE transgastric view).

• Exclude significant MS by measuring transmitral gradient (2D TEE CW Doppler) and MVA (2D TEE transgastric basal SAX view, 3D TEE). For an optimal result, transmitral gradient should be <4 mmHg
• Look for residual interatrial shunt and the defect size. In case of a large shunt, device closure may be needed
• Confirm that there is no pericardial effusion or no increase in pre-existing pericardial effusion.

Figure 47: Schematic diagram showing an ostium secundum type of atrial septal defect and its margins, as visualized from the right atrial side. Different TEE multiplane angles are shown, along with the rims seen in those views. Green - SVC rim; red - aortic rim anteriorly and posteroinferior atrial rim posteriorly; white - mitral rim anteriorly and posterosuperior atrial rim posteriorly; yellow - IVC rim. IVC: Inferior vena cava, SVC: Superior vena cava, TEE: Transesophageal echocardiography, TV: Tricuspid valve Click here to view

Figure 48: Two-dimensional transesophageal echocardiographic visualization of an ostium secundum atrial septal defect. IVC: Inferior vena cava, RA: Right atrium, RSPV: Right superior pulmonary vein, SVC: Superior vena cava Click here to view

1. In 0° ME four-chamber view [Video 33], the imaging plane passes caudal to insertion of right superior pulmonary vein and shows posterosuperior atrial rim (left side of image display, measured from posterior wall of LA to the edge of ASD) and the mitral rim (right side of image display, measured from hinge point of AML to the edge of ASD). The largest anteroposterior diameter of ASD and the total anteroposterior length of the septum can also be measured
2. At 0°, withdrawing the probe to SVC-RA junction level with clockwise (rightward) rotation of the probe, opening of the right superior pulmonary vein can be seen [Video 34]. At this level, electronic plane rotation to 30°-40° degrees shows both superior and inferior pulmonary veins opening into the LA with carina between the two openings
3. The anomalous right sided pulmonary vein draining into SVC, SVC-RA junction or RA free wall can be visualized at 0° imaging plane with the probe rotated extreme rightwards (clockwise) and slightly withdrawn. The probe is then gradually advanced deeper starting from the long-axis view of right pulmonary artery, carefully scanning entire length of SVC to SVC-RA junction to RA free wall
4. From 0° ME four-chamber view, gradual sweep to 30°-60° visualizes the entire posterior atrial margin of the ASD on the left side of the image display [Video 35] and [Video 36]. At approximately 60° (SAX view), the anticlockwise (leftward) rotation of the probe shows the opening of the left superior pulmonary vein into LA, adjacent to LAA. Keeping the left superior pulmonary vein positioned in the center of the image and electronically rotating the imaging plane to 120°-130° with extreme anticlockwise (leftward) rotation of the probe, both left superior and inferior pulmonary veins opening into LA can be seen together, with the carina between the two openings
5. Left-side pulmonary veins draining anomalously into vertical vein can be visualized in 90° imaging plane with leftward rotation of TEE probe and then slowly withdrawing the transducer from LA level to SAX view of arch of aorta. With this maneuver one can trace the vertical vein coursing anterior to left pulmonary artery and draining into innominate vein anterior to aortic arch. The anomalously draining left pulmonary veins into coronary sinus can also be visualized by first identifying the SAX view of coronary sinus posterior to MV annulus in 90° imaging plane and then rotating the TEE probe to the left
6. The ME 60° view shows the aortic rim on the right side of the image display [Video 36]. This view (cable axial view) is useful during TEE guidance of ASD device closure. When the interventionist grounds the device delivery sheath in the left superior pulmonary vein, one can track the opening and deployment of the LA disc when it is hitched towards the ASD. If the aortic root margin is completely absent, the large LA disc may get oriented perpendicular to the septum with the anterior lip of the disc prolapsing through the ASD. This would prompt the interventionist to adopt a different strategy for device deployment
7. At 70°-90°-110°, the imaging plane sweeps the interatrial septum vertically with the posteroinferior atrial rim of the ASD seen on the left side of the image display
8. At 60°-80°, the probe can be advanced deeper towards gastroesophageal junction with gentle clockwise (rightward) rotation to image the IVC in its long-axis opening into the RA. The IVC rim of the defect is seen near the apex of the image sector and Eustachian valve is seen anterior to the IVC opening. It is usually difficult to profile the IVC rim well in this view, because of the proximity of the IVC to the lower esophagus. To overcome this, the TEE probe may be advanced further into the stomach and retroflexed and then gently withdrawn back to the gastroesophageal junction level. This maneuver helps in moving the probe and also esophagus away from the IVC, improving visualization of the IVC rim of the ASD in 60°-80° imaging plane.^[46] The rim length is measured from the posteroinferior wall of the LA to the inferior edge of the ASD, keeping IVC opening in sight. The supero-inferior diameter of the ASD and the total supero-inferior septal length are also measured in this view. ASDs with the absent posteroinferior and/or IVC rims are usually larger and are associated with greater chances of failure of the device closure and device embolization
9. At 90°-110° imaging plane, the probe can be withdrawn with gentle clockwise (rightward) torque to visualize the SVC opening into the RA, SVC rim of the ASD (on the right side of the image display) and the RA appendage (seen anteriorly) [Video 37]. With further clockwise rotation, the right superior pulmonary artery is seen in cross-section behind the SVC. The normal opening of the right superior pulmonary vein into LA can also be seen (may need increasing the angle to 110°-120°) and when it is anomalously connected to SVC, the same can be diagnosed in this view. The SVC rim length is measured from the superior edge of the ASD to the insertion of the septum posterior to SVC opening, just opposite to where right pulmonary artery crosses the SVC
10. Finally, if 3D TEE is available, the same can be used to permit en face visualization of the entire ASD [Figure 49].

Figure 49: Three-dimensional transesophageal echocardiographic visualization of an ostium secundum atrial septal defect from right atrial side Click here to view

Figure 50: Upper panel - Different shapes of left atrial appendage. (a) Windsock, (b) chicken-wing, (c) cactus, and (d) cauliflower shape. Lower panel - Different shapes of the ostium of left atrial appendage. (a) Circular, (b) elliptical, (c) triangular, (d) water drop like, (e) foot like Click here to view

Figure 51: (a) A large left atrial thrombus (arrow). (b) Comb-like parallelly arranged pectinate muscles (arrow) Click here to view

Figure 52: Visualization of the left atrial appendage in different imaging planes Click here to view

Figure 53: A Watchman® left atrial appendage occlusion device in place (arrow). The right-side image shows color Doppler evaluation to rule out any residual peri-device leak Click here to view

Figure 54: Use of three-dimensional echocardiography with multiplanar reconstruction for selecting appropriate image plane for obtaining various aortic measurements Click here to view

Figure 55: Three-dimensional transesophageal echocardiographic measurement of aortic root dimensions. (a) Diameter measurement of aortic root at the sinus of valsalva, sinotubular junction and ascending aorta, (b) Measurement of aortic annular area and perimeter Click here to view

Figure 56: Three-dimensional transesophageal echocardiography for the measurement of coronary ostial height from the aortic annulus. (a) Right coronary ostial height, (b) Left coronary ostial height Click here to view

• Optimize 2D image in the 3-chamber long-axis view
• Use 3D zoom
• Include LVOT and the aortic root till the sinotubular junction completely
• Acquire in 3D mode
• Align the sagittal and coronal lines to get the long-axis of the LVOT and aorta
• Then align the transverse line below the hinge point perpendicular to the above 2 lines
• Measure aortic annulus area or diameter
• Distance of left and right coronary arteries from the annulus can also be measured
• Leaflet length can be measured.

• TV is a more distant structure
• Lower-esophageal view is less clear due to the curve of the esophagus
• TV has thin leaflets and hence more dropouts
• Limited imaging windows available for TV visualization.
• TV is more prone for artifacts originating from other structures like atrial septum

Figure 57: Two-dimensional mid-esophageal four-chamber view of tricuspid valve at a higher level with ATL viewed (a), and at a lower level with PTL viewed (b). (c and d) Three-dimensional image of tricuspid valve with arrows showing the angles it has been imaged to obtain STL, ATL and PTL. ATL: Anterior tricuspid leaflet, PTL: Posterior tricuspid leaflet, STL: Septal tricuspid leaflet Click here to view

Figure 58: (a) Two-dimensional mid-esophageal short-axis view of tricuspid valve. (b and c) Three-dimensional image of tricuspid valve with arrows showing the angles it is to be imaged to obtain STL, ATL and PTL. ATL: Anterior tricuspid leaflet, AV: Aortic valve, IAS: Interatrial septum, PTL: Posterior tricuspid leaflet, STL: Septal tricuspid leaflet Click here to view

Figure 59: (a) Two-dimensional mid-esophageal bicaval view of tricuspid valve in left image, with corresponding orthogonal view in the right image. (b) Three-dimensional image of tricuspid valve with arrow showing the angle it has been imaged to obtain ATL and PTL. ATL: Anterior tricuspid leaflet, PTL: Posterior tricuspid leaflet Click here to view

Figure 60: (a) Two-dimensional mid-esophageal bicaval view of tricuspid valve showing ATL and PTL. (b) Mild tricuspid regurgitation. ATL: Anterior tricuspid leaflet, PTL: Posterior tricuspid leaflet Click here to view

Figure 61: Two-dimensional transgastric biplane view. All three leaflets of tricuspid valve are seen in the left image, while the corresponding image on right shows PTL and ATL. ATL: Anterior tricuspid leaflet, PTL: Posterior tricuspid leaflet, STL: Septal tricuspid leaflet Click here to view

Figure 62: Two-dimensional deep transgastric view of all three leaflets of tricuspid valve. ATL: Anterior tricuspid leaflet, PTL: Posterior tricuspid leaflet, STL: Septal tricuspid leaflet Click here to view

Figure 63: Two-dimensional deep transgastric view of tricuspid valve in systole (a) and diastole (b). Four-chamber view is seen in the left image and two-chamber view in the right image. ATL: Anterior tricuspid leaflet, PTL: Posterior tricuspid leaflet, STL: Septal tricuspid leaflet Click here to view

Figure 64: Initial scout three-dimensional view of tricuspid valve. Left image is at 0° mid-esophageal view with corresponding bicaval view in the right image Click here to view

Figure 65: Three-dimensional view of tricuspid valve, from atrial (a) and ventricular (b) sides Click here to view

Figure 66: Three-dimensional view of tricuspid valve in systole (a) and diastole (b) Click here to view

Figure 67: Three-dimensional view of all the valves, coronary arteries and coronary sinus. AV: Aortic valve, CS: Coronary sinus, LCA: Left coronary artery, MV: Mitral valve, PV: Pulmonary valve, RCA: Right coronary artery, TV: Tricuspid valve Click here to view

Figure 68: Three-dimensional view of TV, showing various adjacent structures from atrial and ventricular sides. (a) AV and MV, (b) PV and MV, (c) RCC and NCC of AV, AML, CS, RAA and RCA. AML: Anterior mitral leaflet, AV: Aortic valve, CS: Coronary sinus, MV: Mitral valve, NCC: Noncoronary cusps, PV: Pulmonary valve, RAA: Right atrial appendage, RCA: Right coronary artery, RCC: Right coronary cusps, TV: Tricuspid valve Click here to view

Figure 69: Three-dimensional view of tricuspid valve, from atrial (a) and ventricular (b) sides showing the three leaflets. ATL: Anterior tricuspid leaflet, PTL: Posterior tricuspid leaflet, STL: Septal tricuspid leaflet Click here to view

Figure 70: Three-dimensional view of tricuspid valve, from atrial side showing the three commissures. APC: Anteroposterior commissure, ASC: Anteroseptal commissure, PSC: Posteroseptal commissure Click here to view

Figure 71: Three-dimensional view of tricuspid annulus, from atrial side. Yellow line is the high point, while the red line is the low point of the saddle shaped annulus. AL: Anterolateral, AS: Anteroseptal, PL: Posterolateral, PS: Posteroseptal Click here to view

Role in Special Settings

• ME four-chamber view at 0°,
• ME SAX view of aortic valve at 45°-60°,
• ME LV two-chamber view at 90°,
• ME LV long-axis view at 110°,
• ME bicaval view at 90°.

Figure 72: Left ventricular assist device inflow cannula is seen at the left ventricular apex (red arrows). Color flow is seen coming from mitral valve and entering the inflow cannula Click here to view

Figure 73: Characteristic finding of continuously closed aortic valve in a patient on left ventricular assist device support. The flow from the inflow cannula bypasses the aortic valve and directly enters the ascending aorta via the outflow cannula Click here to view

Figure 74: Doppler sampling at the inflow cannula, with normal flow velocities Click here to view

1. TEE in cardiac arrest has been shown to be helpful in identifying presence or absence of intrinsic cardiac contraction and distinguishing pulseless electrical activity from true asystole,
2. It helps in the dynamic evaluation of effectiveness of chest compressions,^[75]
3. In as many as 20% of cases, it can identify the cause of arrest such as severe hypovolemia, cardiac tamponade, massive pulmonary embolism, aortic dissection, and myocardial rupture.

• ME four-chamber view,
• ME two-chamber view,
• ME long-axis view,
• ME bicaval view,
• Transgastric SAX view, and
• Descending aorta views.

• Possibility of esophageal or gastric rupture, and
• Lack of definitive airway.

Table 2: Advantages and limitations of micro-transesophageal echocardiography probe Click here to view

Role of Training on Mannequin Simulator

Figure 75: The use of mannequin simulator for imparting “hands-on” training in transesophageal echocardiography Click here to view

Conclusions

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