Imaging the Atrial Septum Using Real-Time Three-Dimensional Transesophageal Echocardiography: Technical Tips, Normal Anatomy, and Its Role in Transseptal Puncture

Atrial septal pouches and ridges: Morphological features and potential implications in clinical practice

Incomplete or irregular fusion of the interatrial septum may result in several anatomic variants, including atrial septal pouches and ridges, whose knowledge and recognition are still poorly widespread in clinical practice. An educational review focused on the definition, clinical significance and diagnostic work-up of these anatomic findings was performed using PubMed, MEDLINE, Embase and Cochrane Central databases up to June 2023. Atrial septal pouches and ridges have been associated with an increased difficulty of catheter-based interventions requiring a transseptal approach, due to procedural challenges for transseptal puncture and the restricted motion of guidewires and catheters through the transseptal access. Additionally, left atrial septal pouch may serve as a thrombogenic nidus and a source of systemic embolism, mostly in the presence of factors leading to higher left atrial pressure and/or atrial blood stasis, which increase the risk of thrombus formation and embolic events, rather than for the only presence of left atrial septal pouch itself. Further investigations are needed in order to better elucidate the implications of such anatomic findings in daily clinical practice, and to provide the most appropriate decision-making strategies.

Three-dimensional transesophageal echocardiography-guided transseptal puncture for percutaneous mitral valve edge-to-edge repair post-percutaneous atrial septal defect closure

Key Clinical Message

Three-dimensional multiplanar analysis and real-time three-dimensional guidance using transesophageal echocardiography can help to identify and access the ideal position for transseptal puncture even in the presence of atrial septal occluders.

Abstract

Transseptal puncture (TSP) for the percutaneous mitral valve edge-to-edge repair (PMVR) after percutaneous atrial septal defect (ASD) closure is a rare and challenging issue. Here, we present a case illustrating the feasibility of real-time three-dimensional transesophageal echocardiographic guidance for TSP without ASD closure device injury.

Three-dimensional transoesophageal echocardiography: how to use and when to use-a clinical consensus statement from the European Association of Cardiovascular Imaging of the European Society of Cardiology

Three-dimensional transoesophageal echocardiography (3D TOE) has been rapidly developed in the last 15 years. Currently, 3D TOE is particularly useful as an additional imaging modality for the cardiac echocardiographers in the echo-lab, for cardiac interventionalists as a tool to guide complex catheter-based procedures cardiac, for surgeons to plan surgical strategies, and for cardiac anaesthesiologists and/or cardiologists, to assess intra-operative results. The authors of this document believe that acquiring 3D data set should become a 'standard part' of the TOE examination. This document provides (i) a basic understanding of the physic of 3D TOE technology which enables the echocardiographer to obtain new skills necessary to acquire, manipulate, and interpret 3D data sets, (ii) a description of valvular pathologies, and (iii) a description of non-valvular pathologies in which 3D TOE has shown to be a diagnostic tool particularly valuable. This document has a new format: instead of figures randomly positioned through the text, it has been organized in tables which include figures. We believe that this arrangement makes easier the lecture by clinical cardiologists and practising echocardiographers.

Imaging the mitral valve: a primer for the interventional surgeon

Transcatheter mitral valve interventions (TMVI) have evolved over the past decade as alternatives to open surgical repair for the therapeutic management of patients with severe mitral regurgitation (MR). Concurrent with the development of these technologies, quality multi-modality cardiac imaging has become essential in patient selection and procedural guidance. The former involves assessments of the pathophysiologic mechanisms of regurgitation, valvular anatomy and morphology, as well as objective quantification of the severity of MR. Both transthoracic and transesophageal echocardiography (TEE) are crucial and serve as the gateway to diagnosis and management of mitral valvular disease. Along with multi-detector computed tomography (CT) and cardiac magnetic resonance imaging (CMR), echocardiography plays an important role for preprocedural planning and evaluation of the spatial relationships of the mitral valvular complex with the coronary sinus, circumflex coronary artery and left ventricular (LV) outflow tract. Procedures that target mitral leaflets (e.g., MitraClip, PASCAL) or annulus (e.g., Cardioband, Carillon), or provide chordal (e.g., NeoChord, Harpoon) or valvular replacement, tend to be guided by TEE and assisted by fluoroscopy. As newer devices become available and outcomes of TMVI improve, cardiac imaging will undoubtedly continue to play an essential role in the success of percutaneous mitral valve repair (MVr) and replacement. The interventional surgeon of the future must therefore have a thorough understanding of the various imaging modalities while synthesizing and integrating novel concepts (e.g., neo-LV outflow tract) as applicable to assessing valvular function and pathology.

Imaging for Patient's Selection and Guidance of LAA and ASD Percutaneous and Surgical Closure

This review comprises 2 main subjects: the percutaneous and surgical closure of the left atrial appendage (LAA) and atrial septal defect (ASD). The aim of the authors was to provide a detailed description of: 1) anatomy of LAA, normal interatrial septum, and the various types of ASD as revealed by noninvasive imaging techniques; 2) preprocedure planning of secundum ASD and LAA percutaneous closure; 3) key steps of the procedural guidance emphasizing the role of 2-dimensional/3-dimensional transesophageal echocardiography; and 4) surgical closure of LAA and ASD.

Ridges and Pouches: A Case Series of Anomalous Atrial Septal Fusion

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Left atrial ridge may affect planning of trans-septal approach for interventions.

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Left atrial septal pouch may become a nidus for thrombus and source of embolus.

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Complete interrogation of the atrial septum can identify these anatomic variants.

Percutaneous Mitral Valve Repair: Multi-Modality Cardiac Imaging for Patient Selection and Intra-Procedural Guidance

Percutaneous mitral valve repair is an important procedure for patients at high risk of surgical mitral valve repair. Multi-modality Cardiac Imaging plays a key role in these procedures. MitraClip is the first and most utilized percutaneous mitral repair device and experience is has grown to treat not only typical but atypical and complex lesions. Cardioband is an emerging percutaneous annuloplasty system with promising early results. This review will focus on the comprehensive multi-modality cardiac imaging for patient selection and intra-procedural guidance of the MitraClip and Cardioband systems.

Revisiting Anatomy of the Interatrial Septum and its Adjoining Atrioventricular Junction Using Noninvasive Imaging Techniques

Interest in the anatomy of the interatrial septum (IAS) and its adjoining atrioventricular (AV) junction has risen enormously in the past two decades with the simultaneous evolution of left-sided percutaneous structural heart disease and complex electrophysiologic procedures. These procedures require, in fact, a direct route to the left atrium through the IAS. Thus, a thorough understanding of the complex anatomy of the IAS and AV junction is essential for performing a safe and effective transseptal puncture. There is a large amount of literature carefully describing the anatomy of the IAS and AV junction. These studies are based almost exclusively on anatomic specimens. Conversely, in this review the authors emphasize the role of noninvasive imaging techniques, in particular cardiac magnetic resonance, two- and three-dimensional transesophageal echocardiography, and computed tomography in visualizing specific aspects of the normal IAS and AV junction. Where appropriate, the authors present images side by side, with corresponding anatomic specimens.

Percutaneous Transcatheter Edge-to-Edge MitraClip Technique: A Practical "Step-by-Step" 3-Dimensional Transesophageal Echocardiography Guide

Recent innovations and advancements in 3-dimensional (3D) echocardiography allow for better understanding of anatomic relationships and improve communication with the interventional cardiologist for guidance of catheter-based interventions. The mitral valve lends itself best for imaging with transesophageal echocardiography (TEE). Consequently, the role of 3D TEE in guiding catheter-based mitral interventions has been evolving rapidly. Although several publications have reported on the advantages and role of 3D TEE in guiding one or more of the steps involved in percutaneous mitral valve repair using the MitraClip, none offer a comprehensive and practical user-friendly guide. This review article provides the reader with practical intraprocedural tips on use of 3D TEE to guide all relevant steps involved in the procedure including how to acquire the images needed and what to look for.

Which Cardiac Structure Lies Nearby? Revisiting Two-Dimensional Cross-Sectional Anatomy

Two-dimensional (2D) transthoracic echocardiography is one of the most used diagnostic tools in clinical cardiology. Similarly, 2D transesophageal echocardiography is considered an indispensable tool for cardiologists and cardiac anesthesiologists worldwide. However, because of their tomographic nature, both techniques display only thin cut planes of a given area of the heart, which are far from representing the "anatomic reality." It is widely accepted that experienced echocardiographers are able to reconstruct mentally a three-dimensional image of any cardiac structure on the basis of their interpretation of multiple tomographic slices. However, this may not be the case with less experienced echocardiographers. In particular, the authors noticed that less experienced echocardiographers are almost totally unaware of which structures lie "nearby" a given 2D tomographic plane, that is, what is adjacent in the elevation plane. In this article, the authors report the use of three-dimensional transesophageal echocardiographic images to discover which structures are located nearby (i.e., "behind" and "in front") the corresponding 2D cross-sections. The authors believe that this novel use of three-dimensional echocardiography is a unique aid to disclose what cannot be seen in a given 2D cross-section, thereby expanding our understanding of 2D echocardiographic anatomy. This may be an effective method to encourage all to "think" in three dimensions, even when they use 2D echocardiography.

Transesophageal echocardiography for the assessment of left atrial appendage thrombus: Study of the additional value of systematic real time 3D imaging after regular 2D evaluation

BACKGROUND

Two-dimensional transesophageal echocardiography (2DTEE) is currently validated for left atrial appendage (LAA) thrombus assessment but has some limitations.

AIMS

To evaluate the performance and interest of systematic real time three-dimensional transesophageal echocardiography (3DTEE) for LAA thrombus assessment, when performed after 2DTEE.

METHODS AND RESULTS

Consecutive patients undergoing TEE were prospectively included. LAA was first evaluated using 2DTEE, and patients were classified as "2D-NT" if no thrombus was found, "2D-T" in case of clear thrombus, or "2D-EQ" if equivocal. Then, 3DTEE of the LAA was performed and patients were similarly classified as "3D-NT," "3D-T," or "3D-EQ." Additional LAA CT scan was only performed if LAA thrombus was not clearly ruled out or confirmed by TEE. Additional value of 3DTEE after 2DTEE LAA evaluation was then assessed. We included 104 patients undergoing TEE. Agreement between 2DTEE and 3DTEE was very good for thrombus diagnosis (k = 0.936), but moderate for vacant LAA (k = 0.562) due to more frequent 2D-EQ than 3D-EQ (11.5% vs 2.9%; P = .016). 3DTEE allowed to refine the LAA status in 11 of 12 (91.7%) 2D-EQ patients: 10 3D-NT, 1 3D-T, and 1 3D-EQ. Coupling 3DTEE to 2DTEE permitted a definite LAA diagnosis in 103 of 104 (99%) vs 92 of 104 (88.5%) patients when 2DTEE was used alone (P = .002). Nine (8.7%) LAA thrombi were diagnosed, and 3 CT scan were performed.

CONCLUSION

3DTEE of the LAA is more effective for thrombus assessment than 2DTEE. 3DTEE should be particularly considered in case of equivocal 2DTEE, as it allows to reach a definite LAA diagnosis in almost all of the patients.

Strategy for Monitoring Cardiac Interventions with an Intelligent Robotic Ultrasound Device

In recent years, 3D trans-oesophageal echocardiography (TOE) has become widely used for monitoring cardiac interventions. The control of the TOE probe during the procedure is a manual task which is tedious and harmful for the operator when exposed to radiation. To improve this technique, an add-on robotic system has been developed for holding and manipulating a commercial TOE probe. This paper focuses on the probe adjustment strategy in order to accurately monitor the moving intra-operative catheters. The positioning strategy is divided into an initialization step based on a pre-planning method, and a localized adjustment step based on the robotic differential kinematics. A series of experiments was performed to evaluate the initialization and the localized adjustment steps. The results indicate a mean error less than 10 mm from the phantom experiments for the initialization step, and a median error less than 1.5 mm from the computer-based simulation experiments for the localized adjustment step. Compared to the much bigger image volume, it is concluded that the proposed methods are feasible for this application. Future work will focus on evaluating the method in a more realistic TOE scanning scenario.

Interatrial septal motion as a novel index to predict left atrial pressure

We investigated whether the interatrial septal (IAS) motion of each heartbeat which is observed by transesophageal echocardiography reflects left atrial pressure (LAP) in patients with atrial fibrillation (AF). We studied 100 patients (70 males, age 67 ± 9 years) who underwent catheter ablation for AF. The amplitude of IAS motion was measured using M-mode and averaged for five cardiac cycles. Left and right atrial pressures, the left to right atrial pressure gradient were directly measured during the catheter ablation. In patients with sinus rhythm during measurement, elevated mean LAP, larger maximum left to right atrial pressure gradient, and greater left atrial emptying fraction were associated with IAS motion. The optimal cut-off value of the IAS motion for predicting high LAP (mean LAP > 15 mmHg) was 8.5 mm (sensitivity 100%, specificity 70.1%) in patients with sinus rhythm during pressure measurement. In addition, all patients were divided into 6 groups based on rhythm during measurement and cutoff value of IAS motion. In patients with sinus rhythm during measurement, low IAS motion group had a highest prevalence of elevated LAP compared with high IAS motion group (64 vs. 0%, P < 0.0001). The amplitude of interatrial septal motion during sinus rhythm reflects left atrial pressure in patients with atrial fibrillation. Interatrial septal motion could be a new index to predict elevated left atrial pressure.

Role of 3D Echocardiography in Cardiac Surgery: Strengths and Limitations

PURPOSE OF REVIEW

This review aims to highlight the general and specific strengths and limitations of intraoperative 3D echocardiography. This article explains the value of real-time three-dimensional transesophageal echocardiography (RT 3D TEE) during cardiac surgery and cardiac interventions.

RECENT FINDINGS

Recently published recommendations and guidelines include the use of RT 3D TEE. RT 3 D TEE provides additional value particularly for guidance during cardiac interventions (i.e., transcatheter mitral valve repair, left atrial appendix and atrial septal defect closures), assessment of the mitral valve in surgical repair, measurement of left ventricular outflow tract area for transcatheter valvular replacements, and estimating right and left ventricular volumes and function. The exact localization of paravalvular leakage is another strength of RT 3D TEE. The major limitation is the reduced temporal resolution compared to 2D TEE.

SUMMARY

Three-dimensional echocardiography is a powerful tool that improves communication and accurate measurements of cardiac structures.

Transseptal puncture - Review of anatomy, techniques, complications and challenges

In recent years, the transseptal puncture approach has enabled passage of increasingly large and complex devices into the left atrium. Traditional tools remain effective in creating and dilating the initial puncture, with an acceptable safety profile. Even for skilled operators, the procedure is technically demanding and requires sound understanding of atrial anatomy. Intracardiac echocardiography is useful in cases of previous septal repair, poorly defined fossa ovalis anatomy or when considering patent foramen ovale portal crossing. Iatrogenic atrial septal defect (iASD) is the most commonly encountered long-term complication and there is increasing evidence that larger devices are leading to symptomatic defects. The size of the sheath crossing the septum is the strongest predictor of iASD formation but other factors such as longer procedure times, significant catheter manipulation and high pulmonary pressures also contribute. Transcatheter mitral valve repair involves the use of large 22 Fr catheters which carry alarmingly high rates of defect persistence with precipitation of symptoms and possible influence on mortality. Long-term follow up data, particularly beyond the 12-month period are lacking and resultantly, evidence to guide management is sparse. Refinements of conventional instruments, as well as innovations to puncture the septum without mechanical pressure, herald a progressively safer future for the transseptal technique.

The growing role of echocardiography in interventional cardiology: The present and the future

As structural heart disease interventions continue to evolve to a sophisticated level, accurate and reliable imaging is required for pre-procedural selection of cases, intra-procedural guidance, post-procedural evaluation, and long-term follow-up of patients. Traditionally, cardiovascular procedures in the catheterization laboratory are guided by fluoroscopy and angiography. Advances in echocardiography can overcome most limitations of conventional imaging modalities and provide successful completion of each step of any catheter-based treatment. Echocardiography's unique characteristics rendered it the ideal technique for percutaneous catheter-based procedures. The purpose of this review is to demonstrate the use of the most common and up-to-date echocardiographic techniques in recent non-coronary percutaneous interventional procedures, underlining its inevitable and growing role, as well as illustrating areas of weakness and limitations, and to provide future perspectives.

Novel Solutions Applied in Transseptal Puncture: A Systematic Review

Access to the left atrium is required for several minimally invasive cardiac interventions in the left heart. For this purpose, transseptal puncture (TSP) technique is often performed, perforating the atrial septum under fluoroscopic or/and ultrasound imaging guidance. Although this approach has been used for many years, complications/failures are not uncommon mainly in patients with abnormal atrial anatomy and repeated TSP. Thus, this study presents an overview of methods and techniques that have been proposed to increase the safety and feasibility of the TSP. A systematic review of literature was conducted through the analysis of the articles published between 2008 and 2015. The search was performed in PubMed, Scopus, and ISI Web of Knowledge using the expression “transseptal puncture.” A total of 354 articles were retrieved from the databases, and 64 articles were selected for this review. Moreover, these 64 articles were divided into four categories, namely: (1) incidence studies, (2) intraprocedural guidance techniques, (3) preprocedural planning methods, and (4) surgical instruments. A total of 36 articles focused on incidence studies, 24 articles suggested novel intraprocedural guidance techniques, 5 works focused on preprocedural planning strategies, and 21 works proposed surgical instruments. The novel 3D guidance techniques, radio-frequency surgical instruments, and pre-interventional planning approaches showed potential to overcome the main procedural limitations/complications, through the reduction of the intervention time, radiation, number of failures, and complications.

Wire- and needle potentials facilitating transseptal puncture

BACKGROUND

Transseptal puncture for left heart interventions became a routine procedure guided by fluoroscopy and echocardiography. The use of intracardiac potentials derived from the sheath-transseptal-needle/guidewire-combination may provide helpful information to increase safety of this procedure.

METHODS AND RESULTS

We recorded the intracardiac potentials from the sheath-transseptal-needle/guidewire-combination during the transseptal puncture procedure in 31 consecutive patients (mean age 67.2±8.2years; 21 in sinus rhythm, 10 in atrial fibrillation) designated for ablation of atrial fibrillation by the Cryo-balloon ® technique (Medtronic, Minnesota, USA). The EP-Navigator ® 3-D-image integration tool (Philips Healthcare, Hamburg, Germany) was used for visualization of the device position in relation to the cardiac structures. Typical and reproducible potentials could be derived in all patients for the different device localizations at transseptal puncture procedure. Especially the transition from the muscular interatrial septum into the fossa ovalis could be easily depicted by the changes of both morphology and magnitude of the atrial signal (6.1±2.3mV in sinus rhythm [SR]/3.5±0.9mV in atrial fibrillation [AF] at the muscular interatrial septum and 0.5±0.2mV in SR/0.5±0.1mV in AF in the fossa ovalis).

CONCLUSIONS

The crucial steps of a transseptal procedure can be verified by typical changes (morphology and amplitude) of the intracardiac signals derived from the sheath-transseptal-needle/guidewire-combination in patients with sinus rhythm as well as in atrial fibrillation.

Three-dimensional Echocardiography in Congenital Heart Disease: An Expert Consensus Document from the European Association of Cardiovascular Imaging and the American Society of Echocardiography

Three-dimensional echocardiography (3DE) has become important in the management of patients with congenital heart disease (CHD), particularly with pre-surgical planning, guidance of catheter intervention, and functional assessment of the heart. 3DE is increasingly used in children because of good acoustic windows and the non-invasive nature of the technique. The aim of this paper is to provide a review of the optimal application of 3DE in CHD including technical considerations, image orientation, application to different lesions, procedural guidance, and functional assessment.

Anatomical Basis for the Cardiac Interventional Electrophysiologist

The establishment of radiofrequency catheter ablation techniques as the mainstay in the treatment of tachycardia has renewed new interest in cardiac anatomy. The interventional arrhythmologist has drawn attention not only to the gross anatomic details of the heart but also to architectural and histological characteristics of various cardiac regions that are relevant to the development or recurrence of tachyarrhythmias and procedural related complications of catheter ablation. In this review, therefore, we discuss some anatomic landmarks commonly used in catheter ablations including the terminal crest, sinus node region, Koch's triangle, cavotricuspid isthmus, Eustachian ridge and valve, pulmonary venous orifices, venoatrial junctions, and ventricular outflow tracts. We also discuss the anatomical features of important structures in the vicinity of the atria and pulmonary veins, such as the esophagus and phrenic nerves. This paper provides basic anatomic information to improve understanding of the mapping and ablative procedures for cardiac interventional electrophysiologists.

The right atrium, a forgotten cardiac chamber: An updated review of multimodality imaging

Despite several limitations, two-dimensional echocardiography (2DE) is the standard method for assessing the right atrium (RA) in everyday clinical routine. Cardiac magnetic resonance remains the current "gold standard" for RA visualization and volume quantification. The development of 2DE-derived strain imaging has enabled assessing RA deformation and phasic function in various pathologic conditions. Three-dimensional echocardiography was demonstrated to be more accurate and reproducible than 2DE for cardiac chamber quantification, while also allowing the evaluation of RA phasic function without geometric assumption. The purpose of this review is to summarize currently available data about RA anatomy, phasic function, and mechanics acquired by different imaging modalities.

Interventional Echocardiography: Current Role and Progress

Advances in cardiovascular interventional techniques have enabled percutaneous treatment for a wide spectrum of non-coronary cardiovascular diseases, also known as ‘structural heart diseases (SHD)’. As these therapies are performed without an open-heart surgery, the use of echocardiography is crucial for detailed visualisation of cardiac anatomy, and to provide guidance for optimal success of these catheter-based interventions. This review will describe the key role of the echocardiographic techniques and imaging protocols that are currently used in different catheter-based SHD interventions.

3D TEE during catheter-based interventions

Guidance of catheter-based procedures is performed using fluoroscopy and 2-dimensional transesophageal echocardiography (TEE). Both of these imaging modalities have significant limitations. Because of its 3-dimensional (3D) nature, 3D TEE allows visualizing the entire scenario in which catheter-based procedures take place (including long segments of catheters, tips, and the devices) in a single 3D view. Despite these undeniable advantages, 3D TEE has not yet gained wide acceptance among most interventional cardiologists and echocardiographists. One reason for this reluctance is probably the absence of standardized approaches for obtaining 3D perspectives that provide the most comprehensive information for any single step of any specific procedure. Therefore, the purpose of this review is to describe what we believe to be the most useful 3D perspectives in the following catheter-based percutaneous interventions: transseptal puncture; patent foramen ovale/atrial septal defect closure; left atrial appendage occlusion; mitral valve repair; and closure of paravalvular leaks.

Characterization of atrial septal defect by simultaneous multiplane two-dimensional echocardiography

AIMS

The aim of this study was to assess the value of two-dimensional (2D) transthoracic simultaneous multiplane imaging (SMPI) in the evaluation of suitability for percutaneous atrial septal secundum defect (ASD) closure compared with the golden standard 2D transoesophageal echocardiography (TEE).

METHODS AND RESULTS

Twenty-nine patients with an ASD underwent both SMPI and TEE. Ten patients (34%) were male (age 41 ± 18 years, range 20-74). SMPI assessment of ASD size and rims included xPlane and I-rotate modes. Rims were defined as suitable for ASD percutaneous closure using a cut-off value of 5 mm. There were no significant differences between SMPI in xPlane mode and TEE regarding the sizes of the anterior-posterior dimension (13.7 ± 4.5 vs. 14.5 ± 5.2 mm) and superior-inferior dimension (13.5 ± 3.9 vs. 14.1 ± 5.0 mm, respectively). Agreement for the aortic, atrioventricular, inferior, right upper pulmonary vein, and superior rims was 100, 100, 100, 96, and 96%, respectively.

CONCLUSION

The SMPI technique can reliably assess the dimensions and rim size of a secundum ASD for pre-interventional selection when compared with TEE and has thus the potential to replace TEE.

Role of Transesophageal Echocardiography in Left Atrial Appendage Device Closure

Left atrial appendage (LAA) occlusion or ligation by percutaneously implanted devices is increasingly an alternative management option for atrial fibrillation, particularly for patients who are intolerant or have contraindications for anticoagulation. Echocardiography plays an important part in screening, guidance of implantation, and after-device assessment. Assessment of LAA anatomy suitable for device implantation, thrombus exclusion, guidance of transseptal puncture, localization of catheter, guidance of device deployment, and after-device assessment are all important functions of echocardiography. This article reviews the role of echocardiography in device-based LAA occlusion or ligation.

Artifacts in three-dimensional transesophageal echocardiography

Three-dimensional (3D) transesophageal echocardiography (TEE) is subject to the same types of artifacts encountered on two-dimensional TEE. However, when displayed in a 3D format, some of the artifacts appear more "realistic," whereas others are unique to image acquisition and postprocessing. Three-dimensional TEE is increasingly used in the setting of percutaneous catheter-based interventions and ablation procedures, and 3D artifacts caused by the metallic components of catheters and devices are particularly frequent. Knowledge of these artifacts is of paramount relevance to avoid misinterpretation of 3D images. Although artifacts and pitfalls on two-dimensional echocardiography are well described and classified, a systematic description of artifacts in 3D transesophageal echocardiographic images and how they affect 3D imaging is still absent. The aim of this review is to describe the most relevant artifacts on 3D TEE, with particular emphasis on those occurring during percutaneous interventions for structural heart disease and ablation procedures.

Imaging-based right-atrial anatomy by computed tomography, magnetic resonance imaging, and three-dimensional transoesophageal echocardiography: correlations with anatomic specimens

Nowadays computed tomography, cardiac magnetic resonance imaging, and tridimensional transoesophageal echocardiography provide anatomic images of right-atrial structures with an impressive richness of anatomical details. It is therefore surprising that these techniques are not routinely used as complementary tools in teaching anatomy. This review aims to fill this gap showing the normal anatomy of right atrium as displayed by these sophisticated imaging techniques. A better understanding of right-atrial anatomy is crucial for the treatment of primary right-atrium electrical disorders as well as for catheter-based interventions for structural heart disease. The success of these procedures is, in fact, related to an accurate anatomical pre-procedural assessment. In this review, we describe the normal anatomy and variants of those right-atrial structures relevant for both ablationists and interventionalists.

Transoesophageal echocardiography in the dog

Transoesophageal echocardiography (TEE) allows imaging of the heart through the oesophagus using a special transducer mounted on a modified endoscope. The proximity to the heart and minimal intervening structures enables the acquisition of high-resolution images that are consistently superior to routine transthoracic echocardiography and optimal imaging of the heart base anatomy and related structures. TEE provides high-quality real-time imaging free of ionizing radiation, making it an ideal instrument not only for diagnostic purposes, but also for monitoring surgical or minimally invasive cardiac procedures, non-cardiac procedures and critical cases in the intensive care unit. In human medicine, TEE is routinely used in these settings. In veterinary medicine, TEE is increasingly used in referral centres, especially for perioperative assessment and guidance of catheter-based cardiovascular procedures, such as patent ductus arteriosus, balloon valvuloplasty, and atrial and ventricular septal defect occlusion with vascular devices. TEE can also aid in heartworm retrieval procedures. The purpose of this paper is to review the current uses of TEE in veterinary medicine, focusing on technique, indications and complications.

[Echocardiography during transcatheter interventions. New developments]

Interventional techniques for percutaneous treatment of structural heart disease have become an important option for patients ineligible for conventional operating procedures in cardiovascular medicine. Echocardiography plays an essential role not only for patient selection but also for guiding transcatheter interventions in order to safely accomplish the procedure. Echocardiographic 2D and 3D techniques next to conventional fluoroscopy have therefore become an integral part for monitoring interventional procedures in the catheter laboratory. This review aims to describe new developments for the application of echocardiography during transcatheter interventions in the context of the current literature and current recommendations.

[State of the art: new developments in cardiac imaging]

Cardiac imaging continues to reveal new anatomical and functional insights into heart disease. In echocardiography, both transesophageal and transthoracic three-dimensional imaging have been fully developed and optimized, and the value of the techniques that have increased our understanding of cardiac mechanics and ventricular function is well established. At the same time, the healthcare industry has released new devices onto the market which, although they are easier to use, have limitations that restrict their use for routine assessment. Tomography's diagnostic and prognostic value in coronary artery disease continues to increase while radiation exposure becomes progressively lower. With cardiac magnetic resonance imaging, myocardial injury and recovery in ischemic heart disease and following acute coronary syndrome can be monitored in exquisite detail. The emergence of new combined tomographic and gamma camera techniques, exclusively developed for nuclear cardiology, have improved the quality of investigations and reduced radiation exposure. The hybrid or fusion images produced by combining different techniques, such as nuclear cardiology techniques and tomography, promise an exciting future.

Real-time three-dimensional transesophageal echocardiography-guided atrial fibrillation ablation procedure

Background

Real-time three-dimensional transesophageal echocardiography (RT 3D TEE) is a novel method providing high spatial and temporal resolution imaging of the heart. During pulmonary vein isolation procedures visualization of the atria, interatrial septum and the ablation catheter is of high importance to increase safety. RT 3D TEE might be a useful tool to guide left atrial ablations.

Case report

A 53-year-old man was referred to our hospital to undergo pulmonary vein isolation procedure for the treatment of symptomatic drug-refractory paroxysmal atrial fibrillation. The transseptal puncture was performed under RT 3D TEE-guidance with direct visualization of the interatrial septum and fossa ovalis. RT 3D TEE provided a three-dimensional view of the puncture with “tenting”-sign and the transseptal needle-fossa ovalis angle enhancing the manipulation of the ablation catheter within the left atrium. The ablation catheter was visualized and tracked during the procedure. No adverse events occurred during the procedure.

Conclusion

Our case report demonstrates the feasibility of RT 3D TEE-guided atrial fibrillation ablation procedures. Safety profile might be improved by the real-time direct view of fossa ovalis. Decrease in fluoroscopy time can be achieved by visualizing the ablation catheter during the procedure.