Left Atrial Appendage Anatomy Research Articles

Left atrial appendage anatomy: clinical implications for cardiac procedures.

The Left Atrial Appendage (LAA) is the most common source of thrombi during atrial fibrillation (AF) leading to stroke. With the increasing prevalence of AF and the growing number of patients requiring LAA involved interventions like exclusion and ablation, understanding LAA's anatomical intricacies becomes paramount importance. This study aims to provide anatomical data regarding LAA in relation to these procedures. Total 50 formalin-fixed cadaveric hearts were examined and various morphological and morphometric parameters were noted. The Cauliflower shape LAA (36%) was most common followed by Chicken Wing (34%), Cactus (18%), and Windsock (12%) shapes. The LAA orifice had greater horizontal diameter compared to the vertical diameter and was oval in shape in 64% cases. Diverticular structures called divots/ pits were present surrounding the LAA orifice in 36% cases with high variation in number, size, and distance from orifice. They were most commonly present towards the septal side and posterior wall side around the LAA orifice. The circumflex artery was the closest structure to LAA orifice with less than 5mm distance in 76% cases. Other structures present close to the LAA were the Left Superior Pulmonary Vein and Mitral Valve. According to shape, the Non-Chicken Wing morphology of the LAA was associated with close running left circumflex artery, high OI (Ovality Index) of the orifice, and greater presence of divots. The LAA anatomy is complex with high amount of variability making it difficult to perform successful procedures. Given data can help clinicians in better planning and execution of cardiac interventions involving the LAA.

TCT-549 Association of Left Atrial Appendage Anatomy With Peridevice Leak at Midterm Follow-Up

TCT-549 Association of Left Atrial Appendage Anatomy With Peridevice Leak at Midterm Follow-Up

Left Atrial Septal Pouch (LASP) and Cryptogenic Stroke: A Narrative Review.

Over 20% of ischemic strokes are cardioembolic strokes, necessitating research into thrombus formation locations, particularly the left atrial appendage (LAA). The left atrial septal pouch (LASP), which is linked to thrombus development and stasis, has drawn attention recently as a possible thromboembolic location, especially in atrial fibrillation (AF). The primary aim of this review is to explore LASP's role in cryptogenic strokes and to discuss the methods used to assess LAA anatomy. Imaging modalities such as cardiac computed tomography (CT) and transesophageal echocardiography (TEE) are crucial for diagnosing and characterizing LASP. LASP, found in about one-third of individuals, provides an additional site for thrombus development in the left atrium. The potential clinical implications of LASP-related thromboembolic events include the need for targeted therapeutic strategies, such as anticoagulant medication and, in some cases, consideration of LASP closure to prevent recurrent strokes. Further investigation is required to elucidate LASP's involvement in thromboembolic events and to guide stroke prevention in at-risk patients.

Feasibility study on atrial fibrillation ablation with pulsed field ablation and concomitant occlusion of the left atrial appendage.

Atrial fibrillation (AF) ablation and left atrial appendage occlusion (LAAO) are increasingly performed as individual procedures. Pulsed field ablation (PFA) has significantly reduced procedure duration and may be advantageous for the combined approach. We have launched a programme for simultaneous AF ablation using PFA and LAAO for patients qualifying for both treatments and excluding those with a complex anatomy. We compare procedure duration and fluoroscopy time against individual procedures (either AF ablation or LAAO alone), all performed by the same operators and using consistent technologies. We performed the combined procedure in 10 patients (50% males; median age 70 years) and excluded 2 patients (17%) because of a complex left atrial appendage anatomy. No death, stroke, or major bleeding events, including pericardial effusion, occurred. For single-procedure comparison, 207 AF ablation procedures and 61 LAAO procedures were available. The total median procedure duration was 79 min (range 60-125) for the combined procedure, 71 min (25-241) for individual AF ablation (51 min without and 78 min with 3-dimensional electroanatomic mapping), and 47 min (15-162) for individual LAAO. The respective fluoroscopy times were 21 (15-26), 15 (5-44), and 10 (3-50) min. For the combined procedure, femoral vein access to last PFA application lasted 49 min (34-93) and LAAO added 20 min (15-37). Simultaneous PFA-based AF ablation and LAAO in carefully selected patients is feasible and safe and can be executed within a short overall procedure duration.

A comparison of conventional and advanced 3D imaging techniques for percutaneous left atrial appendage closure.

Understanding complex cardiac anatomy is essential for percutaneous left atrial appendage (LAA) closure. Conventional multi-slice computed tomography (MSCT) and transesophageal echocardiography (TEE) are now supported by advanced 3D printing and virtual reality (VR) techniques for three-dimensional visualization of volumetric data sets. This study aimed to investigate their added value for LAA closure procedures. Ten patients scheduled for interventional LAA closure were evaluated with MSCT and TEE. Patient-specific 3D printings and VR models were fabricated based on MSCT data. Ten cardiologists then comparatively assessed LAA anatomy and its procedure relevant surrounding structures with all four imaging modalities and rated their procedural utility on a 5-point Likert scale questionnaire (from 1 = strongly agree to 5 = strongly disagree). Device sizing was rated highest in MSCT (MSCT: 1.9 ± 0.8; TEE: 2.6 ± 0.9; 3D printing: 2.5 ± 1.0; VR: 2.5 ± 1.1; p < 0.01); TEE, VR, and 3D printing were superior in the visualization of the Fossa ovalis compared to MSCT (MSCT: 3.3 ± 1.4; TEE: 2.2 ± 1.3; 3D printing: 2.2 ± 1.4; VR: 1.9 ± 1.3; all p < 0.01). The major strength of VR and 3D printing techniques was a superior depth perception (VR: 1.6 ± 0.5; 3D printing: 1.8 ± 0.4; TEE: 2.9 ± 0.7; MSCT: 2.6 ± 0.8; p < 0.01). The visualization of extracardiac structures was rated less accurate in TEE than MSCT (TEE: 2.6 ± 0.9; MSCT: 1.9 ± 0.8, p < 0.01). However, 3D printing and VR insufficiently visualized extracardiac structures in the present study. A true 3D visualization in VR or 3D printing provides an additional value in the evaluation of the LAA for the planning of percutaneous closure. In particular, the superior perception of depth was seen as a strength of a 3D visualization. This may contribute to a better overall understanding of the anatomy. Clinical studies are needed to evaluate whether a more comprehensive understanding through advanced multimodal imaging of patient-specific anatomy using VR may translate into improved procedural outcomes.

On preserving anatomical detail in statistical shape analysis for clustering: focus on left atrial appendage morphology.

Statistical shape analysis (SSA) with clustering is often used to objectively define and categorise anatomical shape variations. However, studies until now have often focused on simplified anatomical reconstructions, despite the complexity of studied anatomies. This work aims to provide insights on the anatomical detail preservation required for SSA of highly diverse and complex anatomies, with particular focus on the left atrial appendage (LAA). This anatomical region is clinically relevant as the location of almost all left atrial thrombi forming during atrial fibrillation (AF). Moreover, its highly patient-specific complex architecture makes its clinical classification especially subjective. Preliminary LAA meshes were automatically detected after robust image selection and wider left atrial segmentation. Following registration, four additional LAA mesh datasets were created as reductions of the preliminary dataset, with surface reconstruction based on reduced sample point densities. Utilising SSA model parameters determined to optimally represent the preliminary dataset, SSA model performance for the four simplified datasets was calculated. A representative simplified dataset was selected, and clustering analysis and performance were evaluated (compared to clinical labels) between the original trabeculated LAA anatomy and the representative simplification. As expected, simplified anatomies have better SSA evaluation scores (compactness, specificity and generalisation), corresponding to simpler LAA shape representation. However, oversimplification of shapes may noticeably affect 3D model output due to differences in geometric correspondence. Furthermore, even minor simplification may affect LAA shape clustering, where the adjusted mutual information (AMI) score of the clustered trabeculated dataset was 0.67, in comparison to 0.12 for the simplified dataset. This study suggests that greater anatomical preservation for complex and diverse LAA morphologies, currently neglected, may be more useful for shape categorisation via clustering analyses.

Left Atrial Appendage Closure: What Do We Know?

Atrial fibrillation (AF) is the most common arrhythmia in the United States and the most common cause of embolic cerebrovascular events, with the majority of these thrombi originating in the left atrial appendage. The left atrial appendage (LAA) has separate developmental, ultrastructural, and physiological characteristics from the left atrium. Although LAA anatomy is highly variable, it can be categorized into 4 types: cactus, cauliflower, chicken wing, and windsock. The cauliflower type is associated with higher stroke risk in patients with nonvalvular AF. Although the cornerstone of therapy to prevent embolic strokes from AF has been anticoagulation with thrombin inhibitors, a large group of patients are unable to tolerate anticoagulation due to bleeding. This has led to the development and advancement of multiple surgical and percutaneous LAA closure devices to prevent embolic cerebrovascular accidents without the need for anticoagulation. In this article, we discuss the outcomes of major studies that utilized surgical LAA occlusion and its effectiveness. Furthermore, we summarize nonsurgical methods of LAA closure and future directions regarding LAA closure.

Left atrial appendage volume is an independent predictor of atrial arrhythmia recurrence following cryoballoon pulmonary vein isolation in persistent atrial fibrillation.

Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation in persistent AF (persAF), and cryoballoon PVI emerged as an initial ablation strategy. Symptomatic atrial arrhythmia recurrence following successful PVI in persAF is observed more frequently than in paroxysmal AF. Predictors for arrhythmia recurrence following cryoballoon PVI for persAF are not well described, and the role of left atrial appendage (LAA) anatomy is uncertain. Patients with symptomatic persAF and pre-procedural cardiac computed tomography angiography (CCTA) images undergoing initial second-generation cryoballoon (CBG2) were enrolled. Left atrial (LA), pulmonary vein (PV) and LAA anatomical data were assessed. Clinical outcome and predictors for atrial arrhythmia recurrence were evaluated by univariate and multivariate regression analysis. From May 2012 to September 2016, 488 consecutive persAF patients underwent CBG2-PVI. CCTA with sufficient quality for measurements was available in 196 (60.4%) patients. Mean age was 65.7 ± 9.5 years. Freedom from arrhythmia was 58.2% after a median follow-up of 19 (13; 29) months. No major complications occurred. Independent predictors for arrhythmia recurrence were LAA volume (HR 1.082; 95% CI, 1.032 to 1.134; p = 0.001) and mitral regurgitation ≥ grade 2 (HR, 2.49; 95% CI 1.207 to 5.126; p = 0.013). LA volumes ≥110.35 ml [sensitivity: 0.81, specificity: 0.40, area under the curve (AUC) = 0.62] and LAA volumes ≥9.75 ml (sensitivity: 0.56, specificity 0.70, AUC = 0.64) were associated with recurrence. LAA-morphology, classified as chicken-wing (21.9%), windsock (52.6%), cactus (10.2%) and cauliflower (15.3%), did not predict outcome (log-rank, p = 0.832). LAA volume and mitral regurgitation were independent predictors for arrhythmia recurrence following cryoballoon ablation in persAF. LA volume was less predictive and correlated with LAA volume. LAA morphology did not predict the clinical outcome. To improve outcomes in persAF ablation, further studies should focus on treatment strategies for persAF patients with large LAA and mitral regurgitation.

Centerline depth world for left atrial appendage orifice localization using reinforcement learning.

Left atrial appendage (LAA) occlusion (LAAO) is a minimally invasive implant-based method to prevent cardiovascular stroke in patients with non-valvular atrial fibrillation. Assessing the LAA orifice in preoperative CT angiography plays a crucial role in choosing an appropriate LAAO implant size and a proper C-arm angulation. However, accurate orifice localization is hard because of the high anatomic variation of LAA, and unclear position and orientation of the orifice in available CT views. With the major research focus being on LAA segmentation, the only existing computational method for orifice localization utilized a rule-based decision. Nonetheless, using such a fixed rule may yield high localization error due to the varied anatomy of LAA. While deep learning-based models usually show improvements under such variation, learning an effective localization model is difficult because of the tiny orifice structure compared to the vast search space of CT volume. In this paper, we propose a centerline depth-based reinforcement learning (RL) world for effective orifice localization in a small search space. In our scheme, an RL agent observes the centerline-to-surface distance and navigates through the LAA centerline to localize the orifice. Thus, the search space is significantly reduced facilitating improved localization. The proposed formulation could result in high localization accuracy compared to the expert annotations. Moreover, the localization process takes about 7.3s which is 18 times more efficient than the existing method. Therefore, this can be a useful aid to physicians during the preprocedural planning of LAAO.

Left atrial dimensions and left atrial appendage morphology: differences in paroxysmal versus persistent atrial fibrillation patients

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulmonary vein isolation (PVI) is an effective treatment strategy in symptomatic atrial fibrillation (AF) patients. However, this approach shows worse long-term results in individuals suffering from persistent compared to the paroxysmal type. Purpose The objective was to investigate differences of left atrial (LA) as well as left atrial appendage (LAA) anatomy in persistent AF (persAF) and paroxysmal (PAF) and patients. Methods An observational single center study with a blinded retrospective analysis of cardiac computed tomography angiography (CCTA) images was conducted. Dimensions of LA, posterior wall box, pulmonary veins (PV) as well as LAA size and morphology were assessed and statistically analyzed. All important measures are depicted in the attached figure. Results From 2012 to 2016 a total of 1.103 patients underwent second generation cryoballoon PVI. Prior to PVI, CCTA was available for 725 (65.7%) patients with sufficient quality for measuring in 473 (65.2%). Mean age was 66.3±9.5 years; PAF was present in 277 (58.6%) participants. In persAF LA volume [mL] (111.8; 128.8; p&amp;lt;0.001), posterior wall box area [cm2] (11.9; 13.3; p&amp;lt;0.001) and pulmonary vein ostial dimensions were significantly larger compared to PAF. LAA volume [mL] (9.0; 10.0; p=0.01) and LAA ostial perimeters (66.5; 70.0; p=0.003) were also identified to be larger in persAF. However, there was no difference in LAA morphology (overall distribution: "windsock" 51%; "chicken-wing" 20%; "cauliflower" 15% and "cactus" 13%). Conclusion Compared to PAF, persAF patients had significantly larger LA volumes, posterior wall box areas, PV ostial dimensions as well as LAA volumes and LAA ostial perimeters. LAA morphological types were distributed equally in both groups.

Real-time 3D echocardiographic transilluminated imaging combined with artificially intelligent left atrial appendage measurement for atrial fibrillation interventional procedures.

Aims: This study investigated the feasibility and accuracy of real-time three-dimensional (3D) echocardiographic transilluminated imaging (TrueVue Glass) in left atrial appendage (LAA) anatomical morphology and artificial intelligence (AI)-assisted 3D automated LAA measurement (3D Auto LAA) software in the preoperative evaluation of LAA occlusion (LAAO) in patients with atrial fibrillation (AF). Method and results: Thirty-seven patients with AF were selected. Two-dimensional (2D) and real-time 3D transesophageal echocardiography (RT3D-TEE) were performed preoperatively, using conventional 3D, the new 3D TrueVue Glass mode, and cardiac computed tomography angiography (CCTA) to assess and type the morphology of LAA. Physiological parameters were measured using traditional 2D and 3D manual (3D Manual LAA), 3D Auto LAA, and CCTA. TrueVue Glass for LAA outer contour display was compared with CCTA. Comparisons were based on correlation and consistency in measuring the maximum diameter (LZ max), minimum diameter (LZ min), area (LZ area), and circumference (LZ cir) of LAA landing zone (LZ). Times and variabilities were compared. The concordance rate for external shape of LAA was 97.14% between TrueVue Glass and CCTA. 3D Auto LAA and 3D Manual LAA have a stronger correlation and higher consistency in all parameters. 3D Auto LAA showed higher intra- and interobserver reproducibility and allowed quicker analysis (p < 0.05). LAAO was performed in 35 patients (94.59%), and none of which had serious adverse events. Conclusion: TrueVue Glass is the first non-invasive and radiation-free visualization of the overall external contour of LAA and its adjacent structures. 3D Auto LAA simplifies the measurement, making the preoperative assessment more efficient and convenient while ensuring the accuracy and reproducibility. A combination of the two is feasible for accurate and rapid assessment of LAA anatomy and physiology in AF patients and has practical application in LAAO.

First-in-Human Experience of Using a Universal Steerable Sheath in Implanting Left Atrial Appendage Closure Devices.

Left atrial appendage (LAA) closure (LAAC) device implantation may be challenging in cases with difficult LAA anatomy. A deflectable sheath to approach multiple LAA positions may be helpful. We used a deflectable sheath to implant LAAC devices in 20 patients and included 60 cases using the standard sheaths for comparison. The procedures were successful in all patients without peri-procedural complications. After a median follow-up of 1.52 (IQR: 0.76-2.33) years, none of the patients in the deflectable sheath group had peri-device leak≥3mm and experienced thromboembolic stroke. In the standard sheath group, after follow-up of 2.03 (IQR: 0.87-3.19) years, 2 had peri-device leak≥3mm and 1 experienced thromboembolic stroke. We first proved the idea of using a universal steerable sheath for LAAC device implantation in difficult LAA anatomy, which also allows rapid switching of different LAAC devices.

Atrial fibrillation ablation: the position of computed tomography in pre-procedural imaging

Abstract Atrial fibrillation (AF) is the most common supraventricular arrhythmia. Despite significant advances in its treatment, it still remains one of the leading causes of cardiovascular morbidity and mortality. In the last two decades, pulmonary vein isolation (PVI) was developed as the most effective treatment option. The reported effectiveness of a single ablation procedure ranges from 40% to 69% with single, and up to 88% with repeated procedures, with acceptable safety profile. The PubMed database was searched, using terms including ‘atrial fibrillation ablation’, ‘pulmonary vein isolation’, ‘computed tomography’, ‘pulmonary vein anatomy’ and ‘ovality index’. Papers were reviewed for relevance and scientific merit. Different imaging techniques are used for pre-procedural assessment of left atrial (LA) anatomy, of which computed tomography (CT) is the most common. It allows assessing pulmonary vein (PV) anatomy, the LA wall thickness in different regions and the left atrial appendage (LAA) anatomy, together with excluding the presence of intracardiac thrombi. Pre-procedural PVs imaging is important regardless of the selected ablation technique, however, cryoballoon (CB) ablation seems to be particularly anatomy-dependent. Additionally, CT also permits assessment of several PVs characteristics (geometry, dimensions, angulations, the ostium area, orientation and ovality index (OI), which are essential for the patients’ qualification and designing the strategy of AF ablation. In this paper, we have reviewed the role of CT imaging in patients undergoing ablation procedure due to recurrent/symptomatic atrial fibrillation. Moreover, we discussed the relevant literature.

474 Watchman Flx Device Sizing Based On CT Left Atrial Appendage Area And Perimeter

Introduction: Left atrial appendage (LAA) closure devices offer alternatives to systemic anticoagulation in patients with atrial fibrillation. Device selection is determined by LAA ostial size, morphology and depth. Traditionally, transesophageal echo (TEE) has been utilized for assessing LAA anatomy. This study aims to evaluate if using cardiac computed tomography (CT) area and perimeter better predicts final device selection.

Apêndice Atrial Esquerdo: Anatomia, Função e Importância na Formação de Trombos

The left atrial appendage (LAA) is an extension of the left atrium (LA) and has complex anatomical structure and unique pathophysiological properties. The LAA functions as a decompression chamber during left ventricular (LV) systole and under increased left atrial pressure conditions. Despite previously being considered a relatively insignificant portion of the cardiac anatomy, the LAA has been highlighted as an important structure involved in the genesis of thrombus formation and thromboembolic events. With the recent development of percutaneous closure devices, LAA morphology assessments have become increasingly important. This article aims to describe LAA anatomy and morphology, function assessment parameters, thrombus diagnostic challenges, and the main imaging modalities, particularly transesophageal echocardiography.

Real-world experience with the new Watchman FLX device: Data from two high-volume Sicilian centers. The FLX-iEST registry.

The Watchman-FLX left atrial appendage closure (LAAC) device presents innovative features: higher conformability, reduced length, closed distal "flex-ball" during deployment, and flattened surface. We report our real-world experience with the Watchman-FLX device in two centers with consolidated LAAC expertise. We enrolled 200 consecutive Watchman-FLX patients (2019-2021) in a nonrandomized double-center registry; procedural data and follow-up for midterm clinical outcomes were collected. A control group of 100 patients treated with first-generation Watchman (2.5) was included. According to mean CHAD2 DS2 -VASc (5 ± 1.40) and HAS-BLED (3.8 ± 1.01) scores, the population included in this study was at high risk: 29% had a previous stroke and 56.5% a bleeding event. Main LAAC indications were symptomatic hemorrhage (39.5%), need for triple antithrombotic therapy (39%), gastrointestinal bleeding (32%), and oral anticoagulation intolerance (18%). Transesophageal echocardiography guidance was followed in 93% of cases (48% in general anesthesia and 45% under conscious sedation). Repositioning an FLX device was required in 20% of cases and no complication occurred. In 96% of patients, the first selected device was delivered, while in 4% a device size change was required after the first choice (7% with Watchman 2.5). Peridevice leaks (<5 mm) were found postimplant in two cases (1%). Overall, the procedural success rate was 99.5%. One patient's procedure was unsuccessful (0.5%), due to left atrial appendage(LAA) anatomy; differently, the mean failure rate with Watchman 2.5 was 2%. No device embolization was reported. Complications (8.5%) were mainly related to the access site (3%); major bleedings (1%), and in-hospital death (0.5%) rarely occurred. After a follow-up of 272 ± 173 days, 2.3% of cases experienced a non-device-relatedstroke and 0.6% fatal bleeding. Our registry showed a high procedural success rate of the Watchman-FLX in a high-risk population. According to our experience, the main advantages include easy implanting and repositioning, absence of embolization, good LAA sealing, and low rate of complications in the follow-up period.

Left atrial appendage orifice dimensions in Japanese atrial fibrillation population measured by multiplane transesophageal echocardiography.

Successful implantation of the WATCHMAN device requires an accurate understanding of left atrial appendage (LAA) anatomy and orifice dimensions. Racial differences are observed in LAA size when comparing Asians with non-Asians. A total of 170 patients (123 male, 67.4 ± 9.2years) with paroxysmal or persistent atrial fibrillation (AF) underwent transesophageal echocardiography before catheter ablation or cardioversion (September 2018 to September 2019). As per the recommendations of the WATCHMAN device, the maximal LAA ostial diameters were measured at multiplane angles of 0°, 45°, 90°, and 135°. The majority of patients (121/170, 71%) had an LAA orifice size within 17-25mm. Fifteen (8.8%) patients had undersized (< 17mm) and eight (0.5%) had oversized (> 31mm) LAA. One patient in this population had no LAA. LAA size was significantly larger in patients with persistent AF than in those with paroxysmal AF (23.3 ± 4.2mm vs. 20.0 ± 3.0mm, p < 0.001) and in male patients than in female patients (22.4 ± 4.2 vs. 20.9 ± 3.7mm, p = 0.03). LAA orifice dimension was significantly correlated with CHADS2 score, the left atrial volume (LAV), E/e', and the left ventricular ejection fraction. Persistent AF, body mass index, and LAV were independently associated with LAA orifice dimension in multivariate analysis. This study demonstrated the distribution of LAA orifice dimension in the Japanese AF patients. This finding should be used as a reference to understand the racial characteristics of LAA size for the WATCHMAN procedure.

Gross anatomic relationship between the human left atrial appendage and the left ventricular summit region: implications for catheter ablation of ventricular arrhythmias originating from the left ventricular summit.

The left ventricular summit (LVS) is a source of difficult-to-treat arrhythmias because of anatomical limitations. The aim of this study was to perform detailed research of the left atrial appendage (LAA) anatomy of cadaveric hearts to analyze their complex anatomy and coverage of the LVS. Eighty human formalin fixed hearts (mean age 44.4 ± 15.5, 27.5% females) were investigated. Each LAA size, type, and its relationship to the LVS were analyzed, as well as possible access sites for mapping/ablating electrode. Four types of LAA were observed over two LVS sites that are either accessible or not. The highest coverage over an inaccessible LVS area was observed in the Broccoli type, followed by the Windsock then the Chicken Wing and finally the Cactus types; over the accessible area of the LVS was observed in the Windsock, then in the Chicken Wing, then in the Cactus, and finally in the Broccoli types. The attainable coverage for electrode access is diminished from 25 to 65% because of the complex pectinate muscles and sharp angles. The highest density of the LAA floor made by pectinate muscles can be found in the Broccoli type (p < 0.005), while the Chicken Wing had the highest number of paper-thin-like pouches. The LAA appears to be a promising entry for ablation-qualified patients with the LV summit originate arrhythmias. The complex internal structure of the LAA may complicate ablation procedures. More prominent appendages are promising in more extensive mapping areas over the LVS.

Morphometric topography of the left atrial appendage in human adult heart

Topography of the left atrial appendage is of importance for supraventricular arrhythmias surgery and sealing of the appendage orifice to prevent thromboembolism in cryptogenic strokes. The aim was to explore the common position of the appendage and delineate variants of its adjacent anatomy in human adults by means cadaveric morphometrics. Material and methods . We studied 54 silicone-filled heart specimens of 200–400 g. With the caliper, we measured the distances from the base of the left atrial appendage to the cardiac apex, to the structures of the atrial complex, nearest large blood vessels, as well as to the left coronary artery. Results. The base of the appendage was 87 ± 13.1 mm from the cardiac apex and 49.7 ± 7.0 mm from the right appendage. The distance from the appendage to the superior caval vein (36.4 ± 8.1 mm) was 16 % longer than the distance to the ascending aorta (30.4 ± 6.4 mm), 1.25 times less than the distance to the oval fossa (45.2 ± 6.0 mm), 1.5 times less than the distance to the inferior caval vein (55.5 ± 8.7). The smallest median value (9.6 mm) and the largest variation (1.4–15.2 mm) were found for the distance to the pulmonary trunk. Four pulmonary veins inflowed to the atrium at different distances from the appendage opening. In 59.6 %, we revealed the left upper pulmonary vein to be closest to the auricle. The mouth of that was 43 % higher and 57 % at the same level with the appendage opening ( p = 0.07). The left coronary artery ran 2.63–18.74 mm inferiorly to the appendage. Interrelations of average strength were found for the parameters of atrial complex. The study showed the length of the ventricular complex as being an unpredictable parameter for determining the adjacent anatomy of left atrial appendage. Conclusions. The morphometric parameters and their interrelations are proposed to use as reference values and criteria for determining the normal atrial complex.

A Comparison of the Accuracy of WATCHMAN and WATCHMAN FLX Device Sizing between CT, TEE, and Patient Specific 3D Models

Background and Hypothesis: In patients with Atrial fibrillation (AF), the Left Atrial Appendage (LAA) is the most common site of thrombus formation. The LAA occlusion procedure using the WATCHMAN device implant is an alternative for stroke prevention in AF patients. Transesophageal echocardiogram (TEE) and Computed tomography (CT) scans aid in measuring the LAA to predict implant device sizes. However, due to varying LAA anatomy and limited spatial resolution, the current imaging techniques often predict one of two sized devices. The objective of this retrospective study is to compare the accuracy of measurements made preoperatively of the LAA with those on 3D models to determine if they can be used in preoperative planning. We hypothesize 3D models will be more accurate in predicting device size and any anatomical impediments than traditional TEE planning.&#x0D; Project Methods: There were 21 subjects selected who underwent the WATCHMAN FLX procedure at Parkview Heart Institute in 2021. 3D models of LAA were created from CT scans using a Form 2 3D printer. The device sizes predicted for the procedure were determined from Boston Scientific FLX guidelines based on the maximum LAA orifice diameter from TEE, CT, and 3D models.&#x0D; Results: Two-proportion z-test between the 3D model predicted sizes to the actual size deployed demonstrated no statistical significance (p=0.298) demonstrating no difference between 3D model predicted sizes and actual size deployed. Two-proportion z-test between TEE vs actual size and CT vs actual size demonstrated statistical significance, suggesting a difference between the group's predictions. 3D models predicted the accurate device size for 20/21(95%) subjects. TEE measurements of maximum orifice diameter were, on average, lower compared to CT and 3D model measurements.&#x0D; Conclusion and Potential Impact: 3D printed models provide the most accurate device size predictions and can be used to optimize presurgical planning while reducing intraoperative complications.