Left Atrial Appendage Size Research Articles

The Relationship Between Cardiac CT-based Left Atrial Structure and Epicardial Adipose Tissue and Postablation Atrial Fibrillation Recurrence Within 2 Years.

The aim of this study was to explore the association of cardiac CT-based left atrium (LA) structural and functional parameters and left atrial epicardial adipose tissue (LA-EAT) parameters with postablation atrial fibrillation (AF) recurrence within 2 years. Contrast-enhanced cardiac CT images of 286 consecutive AF patients (median age: 65 y; 97 females) who underwent initial ablation between June 2018 and June 2020 were retrospectively analyzed. Structural and functional parameters of LA, including maximum and minimum volume and ejection fraction of LA and left atrial appendage (LAA), and LA-EAT volume, were measured. The body surface area indexed maximum and minimum volume of LA (LAVImax, LAVImin) and LAA (LAAVImax, LAAVImin), and LA-EAT volume index (LA-EATVI) were calculated. Independent predictors of AF recurrence were determined using Cox regression analysis. The clinical predictors were added to the imaging predictors to build a combined model (clinical+imaging). The predictive performance of the clinical, imaging, and combined models was assessed using the area under the receiver operating characteristics curve (AUC). A total of 108 (37.8%) patients recurred AF within 2 years after ablation at a median follow-up of 24 months (IQR=11, 32). LA and LAA size and LA-EAT volume were significantly increased in patients with AF recurrence (P<0.05). After the multivariable regression analysis, LA-EATVI, LAAVImax, female sex, AF duration, and stroke history were independent predictors for AF recurrence. The combined model exhibited superior predictive performance compare to the clinical model (AUC=0.712 vs. 0.641, P=0.023) and the imaging model (AUC=0.712 vs. 0.663, P=0.018). Cardiac CT-based LA-EATVI and LAAVImax are independent predictors for postablation AF recurrence within 2 years and may provide a complementary value for AF recurrence risk assessment.

Left atrial appendage clipping during hybrid atrial fibrillation ablation: a very long-term, single-center experience

Abstract Background/introduction Epicardial left atrial appendage (LAA) clipping is an effective strategy for stroke prophylaxis in high thromboembolic (TE) and bleeding risk patients with atrial fibrillation (AF). In addition to LAA exclusion from systemic circulation, clipping promotes concomitant appendage isolation, which might have positive impacts on arrhythmia control. Purpose The aim of this study was to report safety, success rate, and the long-term clinical outcomes of LAA clipping in a large cohort of AF patients undergoing concomitant hybrid ablation. Methods Consecutive patients undergoing hybrid AF ablation between 2013 and 2023 were enrolled. Hybrid ablation was performed in a one-step procedure consisting of thoracoscopic epicardial radiofrequency (RF) ablation followed by endocardial mapping and ablation, if needed. Ablation lesion set included pulmonary vein (PV) and posterior wall (PW) isolation, as well as RF applications to the LAA/posterolateral ridge. LAA clipping was performed via Atriclip exclusion system (Atricure, Inc., The Nederlands) after epicardial ablation. Additional endocardial lesions were performed in case of incomplete epicardial ablation or at physician’s discretion. Results A total of 130 patients were included (mean age: 65±9.4; 72.3% males); among them, 19.2% and 55.4% had persistent or long-standing persistent AF, respectively. Mean CHA2DS2-VASC and HAS-BLED were 3.1±1.1 and 2.3+-0.5. Five patients (3.8 %) had absolute contraindication to long-term oral anticoagulation, 3 (2.3%) had previous life-threatening bleeding events, 17 (13.1%) had a previous TE event. The final clip size was 35mm in 90.7% cases. Acute success was achieved in 97.7%; failure was due to LAA size (n=1), proximity to phrenic nerve (n=1), or bypass graft (n=1). One patient had incomplete occlusion due to a large secondary lobe, which required a second clip. No periprocedural complications related to clipping were documented. At a mean follow-up of 51±35 months, one (0.8%) patient had a stroke and 3 (2.3%) a transient ischemic attack (4 events per 552 patient/years; 0.7%). One patient had a microreentrant tachycardia mapped from the area near the LAA clipping. Conclusion In a large cohort undergoing hybrid AF ablation, epicardial LAA clipping was safe and highly successful. Acute failure was rare and due to LAA morphology or proximity to phrenic nerve and bypass graft. Thromboembolic event rate was very low.

Abstract TP274: Challenging the Guidelines or Merely an Observation on Transthoracic Echocardiography

Introduction: Accurate detection of left atrial appendage (LAA) clot is critical in patients before Balloon Mitral Valvotomy (BMV). There is an elevated risk of thrombus formation and ischemic stroke in Rheumatic Heart Disease (RHD). The yearly prevalence of new stroke is 3-7.5% in RHD. Transesophageal Echocardiogram (TEE) has traditionally been the gold standard for LAA clot detection. But it is semi-invasive and have risks. The need for alternatives in this clinical context has prompted this comparative study. Hypothesis: Visualizing LAA on Transthoracic Echocardiogram (TTE) is facile in severe mitral stenosis due to increased LAA size, which is vital for stroke prevention. Methods: In this comparative study, we assessed the diagnostic accuracy of TTE as a non-invasive alternative to TEE for LAA clot detection in patients scheduled for BMV. A total of 150 patients admitted to a tertiary hospital underwent both TTE and TEE before BMV, with TEE as the reference standard for evaluation. Results: The mean age of our study population was 41.4 years, the majority were females (64.7%). The incidence of thrombus in TEE was 30%, with a significant difference in females (37%) vs. males (17%). TTE missed LAA clots in 18.8%, this discrepancy rate was 6% in males and 26% in females, signifying a significant reduction in clot detection in females. TEE exhibited no such limitations in clot detection between genders. TTE displayed sensitivity of 98% and specificity of 81%. The accuracy rate of TTE was 43.3%.Pearson Correlation coefficient and Fishers Exact test confirms significance. The non-invasive nature of TTE, devoid of procedural complexities, positions it as a Cost-effective option. Conclusion: Our study provides compelling evidence supporting the hypothesis that TTE is an effective and practical alternative to TEE for LAA clot detection in RHD patients Further studies are needed in this regard so that the current Class 1C recommendation for TEE before any BMV may need to be revised.

A Study on Variations in Size and Shape of Left Atrial Appendage from Formalin-fixed Cadavers

Introduction: Atrial appendages were once considered vestigial structures with no significant role in atrial function. However, they are now recognized as significantly impacting various pathophysiological conditions, including cardiac thromboembolism and arrhythmias. The left atrial appendage (LAA), in particular, has been found to have significant variations in shape and size, and its relationship with nearby structures, such as the pulmonary veins (PVs), is crucial in planning interventional and surgical procedures in and around the LAA. Although most studies examining variations in the LAA are image-based, few have focused on anatomical studies. Materials and Methods: In this study, we examined heart specimens from 54 cadavers for anatomical dissection at a tertiary care teaching hospital. After removing the heart from the pericardial cavity, we opened the left atrium and examined its interior. Observations were made regarding the LAA orifice and PV orifices, and measurements were taken. Subsequently, we removed the LAA along with a portion of the left atrial wall, observed its shape and number of lobes, and took measurements. To classify the shape, we used a system proposed by Wang et al. based on resemblance to familiar objects. Categorical variables were expressed as percentages and continuous as mean and standard deviation. The institutional research committee and the institutional ethics committee approved the study. Results: The most common shape variant observed was the Chicken Wing type, followed closely by the Windsock type. Specimens with Cauliflower or Cactus morphology were rare, with the Cactus variant being the least common. The LAA orifice was round or oval shaped in most cases. In most cases, the LAA orifice was at the same or lower level as the left superior PV orifice, with a prominent ridge between the two orifices in most patients. We observed most of the appendages to be trilobed, with considerable variations in length and diameter. We found two specimens with unusual morphologies but no specimens with accessory appendages. Conclusions: Based on our study, there are significant differences in findings compared to some of the previous studies reporting the shape variations of LAA. However, our findings are matching with those of some other earlier studies. The variations in the shape and size of LAA orifices and their relationship to PV orifices are similar to those reported in earlier studies. The distribution of variations in the size of LAA was also similar to those reported in earlier studies. Conducting larger studies to explore these variations could aid in designing and developing therapeutic interventions in the LAA.

Postoperative Coagulation Changes in Patients after Epicardial Left Atrial Appendage Occlusion Varies Based on the Left Atrial Appendage Size.

Left atrial appendage occlusion affects systemic coagulation parameters, leading to additional patient-related benefits. The aim of this study was to investigate the differences in coagulation factor changes 6 months after epicardial left atrial appendage occlusion in patients with different LAA morphometries. This is the first study to analyze these relationships in detail. A prospective study of 22 consecutive patients was performed. Plasminogen, fibrinogen, tPA concentration, PAI-1, TAFI and computed tomography angiograms were performed. Patients were divided into subgroups based on left atrial appendage body and orifice diameter enlargement. The results of blood tests at baseline and six-month follow-up were compared. In a population with normal LAA body size and normal orifice diameter size, a significant decrease in analyzed clotting factors was observed between baseline and follow-up for all parameters except plasminogen. A significant decrease between baseline and follow-up was observed with enlarged LAA body size in all parameters except TAFI, in which it was insignificant and plasminogen, in which a significant increase was observed. Occlusion of the left atrial appendage is beneficial for systemic coagulation. Patients with a small LAA may benefit more from LAA closure in terms of stabilizing their coagulation factors associated with potential thromboembolic events in the future.

Three-dimensional intracardiac echocardiography for left atrial appendage sizing and percutaneous occlusion guidance.

Left atrial appendage (LAA) imaging is critical during percutaneous occlusion procedures. 3D-intracardiac echocardiography (ICE) features direct visualization of LAA from multiple cross-sectional planes at a time. We aimed at reporting procedural success of 3D-ICE-guided LAA occlusion and the correlation between pre-procedural transoesophageal echocardiography (TEE) and intraprocedural 3D-ICE for LAA sizing. Among 274 patients undergoing left atrial appendage occlusion (LAAO) with a Watchman FLX, periprocedural ICE guidance was achieved via a commercially available 2D-ICE catheter (220 patients) or a novel (NUVISION™) 3D-ICE one (54 patients). Primary endpoint was a composite of procedural success and LAA sealing at follow-up TEE. Secondary endpoint was a composite of periprocedural device recapture/resizing plus presence of leaks ≥ 3 mm at follow-up TEE. 3D-ICE measurements of maximum landing zone correlated highly with pre-procedural TEE reference values [Pearson's: 0.94; P < 0.001; bias: -0.06 (-2.39, 2.27)]. The agreement between 3D-ICE-based device selection and final device size was 96.3% vs. 79.1% with 2D-ICE (P = 0.005). The incidence of the primary endpoint was 98.1% with 3D-ICE and 97.3% with 2D-ICE (P = 0.99). 2D-ICE patients had a trend towards a higher incidence of periprocedural device recapture/redeployment (31.5% vs. 44.5%; P = 0.09). The secondary endpoint occurred in 31.5% of 3D-ICE patients vs. 45.9% of 2D-ICE ones (P = 0.065). Intracardiac echocardiography-guided LAAO showed a very high success, with no major adverse events. A very high level of agreement for LAA sizing was found between pre-procedural TEE and periprocedural 3D-ICE. 3D-ICE performed significantly better than 2D-ICE for FLX size selection and may provide better guidance during device deployment.

Morphometrical features of left atrial appendage in the atrial fibrillation patients subjected to left atrial appendage closure.

This study aimed to evaluate the morphometrical features of left atrial appendage (LAA) in patients with atrial fibrillation, subjected to LAA percutaneous closure (LARIAT) for stroke prevention. Computed tomography (CT) scans of 51 patients with atrial fibrillation subjected to LARIAT procedure were comparatively evaluated with 50 patients with sinus rhythm (control group). Three-dimensional reconstructions were created using volume-rendering for evaluation. No differences were found in LAA types of distribution (cauliflower: 25.5 vs. 34.0%, chicken wing: 45.1 vs. 46.0%, arrowhead: 29.4 vs. 20.0%, all p > 0.05) between groups. However, the study group was characterized by LAAs with a lower number of lobes. The LAA orifice anteroposterior and transverse diameters (19.3 ± 4.12 vs. 17.2 ± 4.0 mm, p = 0.01 and 25.1 ± 5.1 vs. 20.5 ± ± 4.4 mm, p = 0.001), orifice area (387.2 ± 133.9 vs. 327.1 ± 128.3 mm2, p = 0.02) and orifice perimeter (70.2 ± 12.5 vs. 61.2 ± 11.6 mm, p = 0.04) was significantly larger in atrial fibrillation patients. More oval LAA orifices was found in atrial fibrillation group (94.0 vs. 70.4%, p = 0.001). No statistically significant differences were found in LAA body length (47.4 ± 15.4 vs. 43.7 ± 10.9 mm, p = 0.17), body width (24.7 ± 5.6 vs. 24.4 ± 5.8 mm, p = 0.81), and chamber depth (17.7 ± 3.5 vs. 16.5 ± 3.8 mm, p = 0.11). Calculated LAA ejection fraction was significantly lower in study group compared to healthy patients (16.4 ± 14.9 vs. 48.2 ± 12.9%, p = 0.001). Important morphometrical differences in LAA orifice have been found, which was significantly larger and more oval in patients with atrial fibrillation compared to healthy controls. Although no difference in LAA body type and size was observed; the LAA ejection fraction was significantly lower in atrial fibrillation rhythm patients.

Left atrial appendage sizing for percutaneous closure in virtual reality-a feasibility study.

The complex and highly variable three-dimensional anatomy of the left atrial appendage (LAA) makes planning and device sizing for interventional occlusion procedures (LAAC) challenging. Several imaging modalities [e.g. echocardiography, multi-slice computed tomography (MSCT)] are used for this purpose. Virtual reality (VR) is an emerging imaging technique to immerse into a three-dimensional left atrium and appendage, offering unprecedented options of visualization and measurement. This study aimed to investigate the feasibility, accuracy and reproducibility of visualizing the LAA in VR for preprocedural planning of LAAC. Twenty-one patients (79 ± 7 years, 62% male) who underwent LAAC at University Hospital Düsseldorf were included in our study. A dedicated software generated three-dimensional VR models from preprocedural MSCT imaging data. Conventional measurements of LAA dimensions (ostium, landing zone and depth) using a commercially available software were compared to measurements in VR: MSCT and VR ostium min. (r = 0.93), max. (r = 0.80) and mean (r = 0.88, all p < 0.001) diameters as well as landing zone (LZ) min. (r = 0.84), max. (r = 0.86) and mean diameters (r = 0.90, all p < 0.001) showed strong correlations. Three-dimensional orientation was judged superior by physicians in VR compared to MSCT (p < 0.05). Virtual reality visualization of the left atrium and appendage based on MSCT data is feasible and allows precise and reproducible measurements in planning of LAA occlusion procedures with enhanced 3D orientation. Further studies need to explore additional benefits of three-dimensional visualization for operators in preprocedural planning.

Comparing Multimodal Imaging Methods To Assess Left Atrial Appendage Sizing For Closure: A Metanalysis

Comparing Multimodal Imaging Methods To Assess Left Atrial Appendage Sizing For Closure: A Metanalysis

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.

3D intracardiac echocardiography for left atrial appendage sizing and percutaneous occlusion guidance

Abstract Funding Acknowledgements Type of funding sources: None. Background Left atrial appendage (LAA) imaging is critical during percutaneous occlusion procedures. 3D-intracardiac echocardiography (ICE) features direct visualization of LAA from multiple cross-sectional planes at a time. Purpose To report procedural success of 3D-ICE-guided LAA occlusion and the correlation between pre-procedural transesophageal echocardiography (TEE) and intraprocedural 3D-ICE for LAA sizing. Methods Among 274 patients undergoing LAAO, periprocedural ICE guidance was achieved via a commercially available 2D-ICE catheter (220 patients) or a novel 3D-ICE one (54 patients; Fig.1). Primary endpoint was a composite of procedural success and LAA sealing at follow-up TEE. Secondary endpoint was a composite of periprocedural device recapture/resizing plus presence of leaks≥3mm at follow-up TEE. Results 3D-ICE measurements of maximum landing zone correlated highly with preprocedural TEE reference values [Pearson’s: 0.94; p&amp;lt;0.001; bias: -0.06 (-2.39, 2.27)] (Fig.2). The agreement between 3D-ICE-based device selection and final device size was 96.3% versus 79.1% with 2D-ICE (p=0.005). The incidence of the primary endpoint was 98.1% with 3D-ICE and 97.3% with 2D-ICE (p=0.99). 2D-ICE patients had a trend towards a higher incidence of periprocedural device recapture/redeployment (31.5% vs 44.5%; p=0.09). The secondary endpoint occurred in 31.5% of 3D-ICE patients versus 45.9% of 2D-ICE ones (p=0.065). Conclusions ICE-guided LAAO showed a very high success, with no major adverse events. A very high level of agreement for LAA sizing was found between pre-procedural TEE and periprocedural 3D-ICE. 3D-ICE performed significantly better than 2D-ICE for device size selection and may provide better guidance during device deployment.

PO-04-065 THREE-DIMENSIONAL INTRACARDIAC ECHOCARDIOGRAPHY FOR LEFT ATRIAL APPENDAGE SIZING AND PERCUTANEOUS OCCLUSION GUIDANCE

Left atrial appendage (LAA) imaging is critical during percutaneous occlusion procedures. 3D-intracardiac echocardiography (ICE) features direct visualization of LAA from multiple cross-sectional planes at a time. To report procedural success of 3D-ICE-guided LAA occlusion and the correlation between pre-procedural transesophageal echocardiography (TEE) and intraprocedural 3D-ICE for LAA sizing. Among 274 patients undergoing LAAO with a Watchman FLX, periprocedural ICE guidance was achieved via a commercially available 2D-ICE catheter (220 patients) or a novel (NUVISION™) 3D-ICE one (54 patients). Technical success was defined as successful device implantation without periprocedural evidence of leaks≥3mm on color Doppler. Procedural success was a composite of technical success plus absence of procedure- or device-related major complications. Primary endpoint was a composite of procedural success and LAA sealing at follow-up TEE. Secondary endpoint was a composite of periprocedural device recapture/resizing plus presence of leaks≥3mm at follow-up TEE. We also compared mean and maximum mean and maximum landing zone (LZ) diameters obtained from same patient’s TEE and 3D-ICE; these measurements were used to assess the degree of correlation and agreement between the two imaging techniques. Procedural success was achieved in all 274 patients; all final devices met release criteria. The agreement between 3D-ICE-based device selection and final device size was 96.3% versus 79.1% with 2D-ICE (p=0.005). No major procedure- and device-related adverse events were documented The incidence of the primary endpoint was 98.1% with 3D-ICE and 97.3% with 2D-ICE (p=0.99). 2D-ICE patients had a trend towards a higher incidence of periprocedural device recapture/redeployment (31.5% vs 44.5%; p=0.09). The secondary endpoint occurred in 31.5% of 3D-ICE patients versus 45.9% of 2D-ICE ones (p=0.065). 3D-ICE measurements of maximum and mean LZ correlated highly with preprocedural TEE reference values [Pearson’s: 0.94; p<0.001; bias: -0.06 (-2.39, 2.27)] (Figure 1). ICE-guided LAAO showed a very high success, with no major adverse events. A very high level of agreement for LAA sizing was found between pre-procedural TEE and periprocedural 3D-ICE. 3D-ICE performed significantly better than 2D-ICE for FLX size selection and may provide better guidance during device deployment.

Does the wall thickness of the left atrial appendage and its isthmus depend on their macroscopic characteristics?

Knowledge in interrelations between gross anatomy of the left atrial appendage (LAA) and thickness of the walls of LAA and periauricular area enables decreasing operational risks in LAA ostium occluding and «Cox-Maze» surgery for atrial fibrillation. The aim of the study was to identify significant interrelations between the macroscopic characteristics of the LAA (size, shape, number of lobes) and the parameters of the wall thickness of the LAA and its isthmus. Material and methods. The study includes 50 heart specimens of patients died from non-cardiac diseases. We examined 60 anatomical sections from 30 hearts by means Olympus SZX2-ZB10 microscope, and histological slices from 20 hearts. Results. The layers of the LAA wall were thinner than those in the isthmus. The thickness of LAA walls did not show direct correlation with the external dimensions of LAA. We found inverse correlation (Rs = – 0.4, p &lt; 0,05) between the thickness of the myocardium, endocardium and some external sizes of LAA. The wall thickness of «chicken wing», «cauliflower» and «arrowhead» was the same. The wall of single-lobe LAA was thinner than that of two-lobed LAA (p = 0.036). The LAA isthmus wall was thinner (p = 0.03) in hearts with «cauliflower» LAA compared to hearts with LAA resembled a «chicken wing». Differences in wall thickness in LAA of various shapes were due to the degree of subepicardial fatty tissue development. Intracardiac operations should be done with the utmost care in patients with «cauliflower» LAA and single-lobe LAA to avoid damage of the LAA and periauricular area. Conclusions. The research found clinically significant interrelations between the LAA wall thickness and the number of its lobes as well as between the LAA isthmus wall thickness and LAA shape variants.

Left atrial appendage morphology with the progression of atrial fibrillation.

Left atrial appendage (LAA) size is crucial for determining the indication of transcatheter LAA closure. The aim of this study was to evaluate the differences in LAA morphology according to the types of atrial fibrillation (AF). A total of 299 patients (mean age: 67 ± 13 years) who underwent transesophageal echocardiography (TEE) were included. Patients were classified into non-AF (n = 64), paroxysmal AF (n = 86), persistent AF (n = 87), or long-standing persistent AF (n = 62). LAA morphology, including LAA ostial diameter and depth, was assessed using TEE. Patients with long-standing persistent AF had larger LAA ostial diameter and depth and lower LAA flow velocity. The maximum LAA ostial diameter was 19 ± 4 mm in patients with non-AF, 21 ± 4 mm in patients with paroxysmal AF, 23 ± 5 mm in patients with persistent AF, and 26 ± 5 mm in patients with long-standing persistent AF. LAA ostial diameter was increased by 2 or 3 mm with the progression of AF. LAA ostial diameter was correlated with LA volume index (R = 0.37, P < 0.01) and the duration of continuous AF (R = 0.30, P < 0.01), but not with age or the period from the onset of AF. In conclusion, LAA size was increased with the progression of AF.

Left atrial appendage dimension predicts elevated brain natriuretic peptide in nonvalvular atrial fibrillation.

BNP elevation in patients with AF is observed in the absence of heart failure; however, prior mechanistic studies have not included direct left atrial pressure measurements. This study sought to understand how emptying function of the left atrial appendage (LAA) and LAA dimension contributes to brain-natriuretic peptide elevations (BNP) in atrial fibrillation (AF) accounting for left atrial pressure (LAP). 132 patients referredfor left atrial appendage occlusion (LAAO) were prospectively enrolled in this study. BNP levels and LAP were measured just before LAAO. Statistical analysis considered BNP, rhythm at time of procedure, LAP, LAA morphology, LAA size (ostial diameter, depth, volume), LAA emptying velocity, CHADS2-VASc score, body mass index (BMI), left ventricular ejection fraction (LVEF), estimated glomerular filtration rate (eGFR), and obstructive sleep apnea (OSA) diagnosis as covariates. Bivariate statistical analysis demonstrated positive associations with age, LAA ostial diameter, depth, and volume, LAP, AF status at time of measurement, OSA, and CHADS2-VASc score. BNP was negatively associated with LVEF, eGFR, LAA emptying velocity and BMI. With multivariate logistic regression including LAP as covariate, significant relationships between BNP and AF/AFL(OR 1.99 [1.03, 3.85]), LAP (OR 1.13 [1.06, 1.20]), LAA diameter (OR 1.14 [1.03, 1.27]), LAA depth (OR 1.14 [1.07, 1.22]), and LAA emptying velocity (OR 0.97 [0.96,0.99]) were observed; however, no significant associations were seen with LAA morphology or CHADS2-VASc score. BNP elevations in AF are associated with LAA size and function, but not CHADS2-VASc score or appendage morphology after accounting for changes in LAP.

Clinical Characteristics of Non-Valvular Atrial Fibrillation Patients With a Large Left Atrial Appendage Ostium-Limiting Percutaneous Closure.

The left atrial appendage (LAA) is a therapeutic target for preventing cardioembolic stroke in patients with non-valvular atrial fibrillation (NVAF). A large LAA ostium limits percutaneous LAA closure. This study investigated the characteristics and factors associated with a large LAA ostium in Japanese patients with NVAF.Methods and Results: In 1,102 NVAF patients, the maximum LAA diameter was measured using transesophageal echocardiography (TEE). A large LAA ostium was defined by a maximum diameter of >30 mm. Forty-four participants underwent repeated TEEs, and changes in LAA size under lasting AF were assessed. A large LAA ostium was observed in 3.1% of all participants and 8.9% of patients with long-standing persistent AF (LSAF). The large LAA group had greater CHA2DS2-VASc (P=0.024) and HAS-BLED scores (P=0.046) and a higher prevalence of LAA thrombus (P=0.004) than did the normal LAA group. LSAF, moderate or severe mitral regurgitation, left atrial volume ≥42 mL/m2, E/E' ratio ≥9.5, and left ventricular mass ≥85 mg/m2were independently associated with a large LAA ostium (P<0.001, P<0.001, P=0.009, P=0.009, and P=0.032, respectively). In 44 patients with lasting AF, the LAA ostial diameter increased over time (P<0.001). NVAF patients with a large LAA ostium may have a higher risk of stroke and bleeding. LSAF and factors leading to LA overload may be closely associated with LAA ostial dilatation and can promote it.

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.

PO-696-06 REAL-WORLD EXPERIENCE WITH A NOVEL 3D INTRACARDIAC ECHOCARDIOGRAPHY CATHETER

Intracardiac echocardiography (ICE) is a valuable imaging modality which allows real-time visualization of cardiac anatomy for procedural guidance. The NUVISION™ 4D ICE catheter (Biosense Webster Inc, Irvine, CA) is a novel 10-Fr catheter with fully sampled matrix phased-array transducer capable of real-time 3D imaging. A unique feature of the catheter is the presence of a dedicated knob, which allows independent 360° rotation of the tip. To describe the performance of the NUVISIONTM catheter during different electrophysiology procedures. We included 50 consecutive patients scheduled for electrophysiology procedures between September and November 2021. The primary endpoint was a composite of safety (device-related complications) and efficacy (acute procedural success). A 5-point Likert scale was used to rate the experience with transseptal (TS) access, catheter maneuverability, image quality. Among 50 patients (mean age 70±11, 22% female), 38 (76%) underwent left atrial appendage (LAA) occlusion, 6 (12%) AF ablation, 3 (6%) VT/PVC ablation, and 3 (4%) LAA leak closure with either coils (n=1; 2%) or radiofrequency applications (n=2; 4%). The ICE catheter was advanced through an 11-Fr sheath into the left femoral vein; no access-related complications occurred. TS access was performed in 47 patients (single access: 14 pts; double access: 33 pts). Mean time for each TS access was 3.4±0.7 min; ICE catheter performance during TS was rated as “very good” in 87.2% of cases. Maneuverability was rated as “very good” in 84% of cases; of note, the percentage of “very good” ratings rose from 72% to 96% between the first and the last 25 cases, as a result of the better familiarity and increasing satisfaction of the operators with the rotation knob. The catheter was advanced into the left atrium in 38 LAA procedures. A multiplanar view (Figure 1) was the imaging modality of choice (81.6%) for LAA sizing and during device deployment. A single device was attempted in all patients; 4 patients required device recapture and repositioning. Image quality was rated as “very good” in 98% of cases. No device-related complications occurred; acute procedural success was achieved in all. The NUVISIONTM 3D ICE catheter was safe and may significantly improve procedural guidance.

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.

475 Is left atrial appendage device compression rate a predictor of incomplete occlusion in patients undergoing watchman device implantation?

Abstract Aims Transesophageal echocardiography (TEE) is a standard peri-procedural imaging modality in patients undergoing percutaneous left atrial appendage (LAA) occlusion. An accurate device sizing is pivotal to assess stability and achieve successful closure. In this prospective study, we sought to evaluate the correlation between Watchman device compression rates (DCRs) and risk of incomplete LAA occlusion at follow-up in patients undergoing Watchman device implantation. Methods and results Two-dimensional TEE via a commercially available transducer (Vivid, Philips) was performed during the procedure and within 3 months after the procedure. LAA size, morphology, and DCRs [(original device size—size after deployment)/original device size; %] were assessed in a mid-oesophageal view at 0°, 45°, 90° and 135°, according to company recommendations. Residual leaks ≥ 3 mm were classified as significant. Between 2016 and 2018, 116 patients underwent LAA occlusion with a Watchman device at our institution. The mean age was 74 ± 9 years and 60.4% (n = 70) were males. The average CHA2DS2-VASc and HAS-BLED scores were 4.7 ± 1.7 and 2.5 ± 1.1, respectively. The final device size was 21 mm in 11 (9.5%) patients, 24 mm in 28 (24.1), 27 mm in 27 (23.3%), 30 mm in 26 (22.4%), and 33 mm in 24 (20.7). At follow-up TEE, 16 (13.8%) patients were found to have a significant (≥3 mm) residual leak. The average DCRs measured at different angles in patients with and without leak were not significantly different (24 ± 8% vs. 26 ± 7% at 0°, P = 0.47; 23 ± 9% vs. 25 ± 7% at 45°, P = 0.58; 23 ± 8% vs. 23 ± 6% at 90°, P = 0.61; 22 ± 8% vs. 21 ± 7% at 135°, P = 0.61). At receiver operating characteristic (ROC) analysis, the areas under the curve to discriminate between patients with/without leak were 0.58, 0.57, 0.55, and 0.46 for DCRs measured at 0°, 45°, 90°, and 135° angles. Conclusions Peri-procedural assessment of DCRs does not appear to be an accurate method to predict LAA complete occlusion in patients undergoing Watchman device implantation.