Dimensional Map Research Articles

Differences in the feasibility, anatomical parameters predicting procedural difficulty, and isolation area of a left atrial posterior wall isolation using radiofrequency versus cryoballoon catheters.

The difficulty and outcome of the adjunctive left atrial posterior wall isolation (LAPWI) in patients with persistent atrial fibrillation (PersAF) may be affected by the ablation energy used. This study aimed to compare the completion rate, anatomical parameters predicting procedural difficulty, and the isolation area of a LAPWI between the use of radiofrequency (RFA) and cryoballoon ablation (CBA). We enrolled 95 and 93 patients with PersAF who underwent pulmonary vein isolation (PVI)+LAPWI using RFA (RF group) and CBA (CB group), respectively. Preoperative computed tomography was used to evaluate the anatomical features associated with an incomplete LAPWI. Post-ablation 3-dimensional maps were analyzed to quantify the isolation area. The completion rate of the LAPWI was significantly higher in the RF group than the CB group without touch-up RFA (88.4%vs. 72.0%; p=.005). Predictors of incomplete LAPWI were a longer left inferior pulmonary vein (LIPV)-esophageal distance (p<.001) for RFA and a steeper angle of the LAPW (p<.001) and longer transverse LAPW diameter (p=.016) for CBA. The isolated non-PV area with RFA or CBA alone was significantly greater in the CB group than the RF group (27.5±9.5cm2 vs. 22.9±6.9cm2 ; p<.001). The position of the esophagus at a distance from the LIPV was associated with an incomplete LAPWI using RFA, while a steeper angle of the LAPW and transverse enlargement of the LAPW were associated with that using CBA. The completion rate of the LAPWI was higher with RFA, but the isolation area outside of the PVs was greater with CBA.

Review of interferometric synthetic aperture sonar interferometric phase filtering methods

Interferometric synthetic aperture sonar (InSAS) is a novel three dimensional underwater mapping system, which is widely used in various fields. Interferometric phase filtering is a crucial process in InSAS signal processing. The study of interferogram filtering method has great significance to improve the signal-to-noise ratio (SNR) of interferogram, reduce the difficulty of phase unwrapping, and improve the accuracy of digital elevation maps. Firstly, this article introduces the sources of interferometric phase noise. Secondly, it illustrates the difference between real domain filter and complex domain filter by simulation experiment. Thirdly, the various methods of InSAS interferogram filtering are systematically studied, which can be classified into spatial domain filtering and transform domain filtering. The transform domain filtering can be further divided into frequency domain and wavelet transform filtering. Moreover, the advantages and disadvantages of various methods are analyzed theoretically. Finally, numerical simulation and real-data processing experiments are performed, and the advantages and shortcomings of several methods are compared using residue numbers, root mean square error (RMSE), and CPU time as evaluation criteria.

UAV-Aided Radio Map Construction Exploiting Environment Semantics

This paper constructs a full dimensional (6D) radio map to predict the channel gain between any transmitter location and any receiver location based on received signal strength (RSS) measurements between low-altitude aerial nodes and ground nodes. The main challenge is how to describe the signal strength attenuation due to the blockage from the environment. Conventional interpolation-type approaches fail to exploit the close relation between the radio map and the geometry of the environment. This paper proposes to construct radio maps by first estimating and constructing a multi-class 3D virtual obstacle map that describes the geometry of the environment with radio semantics. Mathematically, a least-squares problem is formulated to jointly estimate the virtual obstacle map and the propagation parameters. This problem is found to have a partial quasiconvexity that leads to the development of an efficient parameter estimation and radio map construction algorithm. Numerical experiments confirm that the proposed method substantially reduces the amount of measurement required for achieving the same radio map accuracy. It is also demonstrated that in a unmanned aerial vehicle (UAV)-aided relay communication scenario, a radio map assisted approach for UAV placement can achieve more than 50% capacity gain.

Result assessment of typical atrial flutter ablation base on application of three-dimensional electroanatomy mapping at Hanoi heart hospital

Background: Atrial flutter is a rare type of arrhythmia in clinical practice, but it is a long-lasting complex arrhythmia that causes uncomfortable symptoms and serious complications. The method of ablation of atrial flutter using X-ray irradiation has many shortcomings such as prolonged irradiation time, and the success rate is only 80-85%. The method of ablation using the 3-Dimensional electrical mapping method has been widely used in typical atrial flutter ablation, but there have not been many studies evaluating its effectiveness, so we carry out this study.&#x0D; Objectives of the study: Assessment for electrocardiography, electrophysiology study characteristic, and ablation result of typical atrial flutter using three-dimensional electrical mapping.&#x0D; Research objects and methods: case series study, 17 patients diagnosed with atrial flutter were electrophysiology study and ablated from 10/2019 to 10/2022 at Hanoi Heart Hospital.&#x0D; Results: Regarding the effectiveness of atrial flutter ablation, 100% of patients with atrial flutter caused a seizure and successfully ablated atrial flutter by RF. In terms of procedure time, our study has an average of 103.53 ± 74.64 minutes for each procedure, of which the fastest is 20 minutes and the longest is 360 minutes. Regarding the time of X-ray irradiation, the average of our study was 10.67 ± 9.86 minutes, of which the shortest was 4 minutes and the longest was 45 minutes.&#x0D; Conclusion: Typical atrial flutter ablation based on 3D mapping application has had high success at Hanoi heart hospital.

Gradients of response latencies and temporal precision of auditory neurons extend across the whole inferior colliculus.

Neural responses to acoustic stimulation have long been studied throughout the auditory system to understand how sound information is coded for perception. Within the inferior colliculus (IC), a majority of the studies have focused predominantly on characterizing neural responses within the central region (ICC), as it is viewed as part of the lemniscal system mainly responsible for auditory perception. In contrast, the responses of outer cortices (ICO) have largely been unexplored, though they also function in auditory perception tasks. Therefore, we sought to expand on previous work by completing a three-dimensional (3-D) functional mapping study of the whole IC. We analyzed responses to different pure tone and broadband noise stimuli across all IC subregions and correlated those responses with over 2,000 recording locations across the IC. Our study revealed there are well-organized trends for temporal response parameters across the full IC that do not show a clear distinction at the ICC and ICO border. These gradients span from slow, imprecise responses in the caudal-medial IC to fast, precise responses in the rostral-lateral IC, regardless of subregion, including the fastest responses located in the ICO. These trends were consistent at various acoustic stimulation levels. Weaker spatial trends could be found for response duration and spontaneous activity. Apart from tonotopic organization, spatial trends were not apparent for spectral response properties. Overall, these detailed acoustic response maps across the whole IC provide new insights into the organization and function of the IC.NEW & NOTEWORTHY Study of the inferior colliculus (IC) has largely focused on the central nucleus, with little exploration of the outer cortices. Here, we systematically assessed the acoustic response properties from over 2,000 locations in different subregions of the IC. The results revealed spatial trends in temporal response patterns that span all subregions. Furthermore, two populations of temporal response types emerged for neurons in the outer cortices that may contribute to their functional roles in auditory tasks.

Sinus rhythm QRS morphology reflects right ventricular activation and anatomical ventricular tachycardia isthmus conduction in repaired tetralogy of Fallot

Patients with repaired tetralogy of Fallot (TOF) are at risk for ventricular tachycardia (VT) related to well-described anatomical isthmuses. The purpose of this study was to explore QRS morphology as an indicator of anatomical isthmus conduction. Patients with repaired TOF and complete right bundle branch block referred for transcatheter pulmonary valve replacement (PVR) or presenting with sustained VT underwent comprehensive 3-dimensional mapping in sinus rhythm. Electrocardiographic characteristics were compared to right ventricular (RV) activation and anatomical isthmus conduction properties. Twenty-two patients (19 pre-pulmonary valve replacement and 3 clinical VT) underwent comprehensive 3-dimensional mapping (median 39 years; interquartile range [IQR] 27-48 years; 12 [55%] male). Septal RV activation (median 40 ms; IQR 34-46 ms) corresponded to the nadir in lead V1 and free wall activation (median 71 ms; IQR 64-81 ms) to the transition point in the upstroke of the R' wave. Patients with isthmus block between the pulmonary annulus and the ventricular septal defect patch and between the ventricular septal defect patch and the tricuspid annulus (when present), were more likely to demonstrate lower amplitude R' waves in lead V1 (5.8 mV vs 9.4 mV; P = .005), QRS fragmentation in lead V1 (15 [94%] vs 2 [13%]; P < .001), and terminal S waves in lead aVF (15 [94%] vs 6 [40%]; P < .001) than those with intact conduction. During catheter ablation, these QRS changes developed during isthmus block. For patients with repaired TOF, the status of septal isthmus conduction was evident from sinus rhythm QRS morphology. Low-amplitude, fragmented R' waves in lead V1 and terminal S waves in the inferior leads were related to septal isthmus conduction abnormalities, providing a mechanistic link between RV activation and common electrocardiographic findings.

The 3-dimensional Lyness map and a self-mirror log Calabi–Yau 3-fold

AbstractThe 2-dimensional Lyness map is a 5-periodic birational map of the plane which may famously be resolved to give an automorphism of a log Calabi–Yau surface, given by the complement of an anticanonical pentagon of $$(-1)$$ ( - 1 ) -curves in a del Pezzo surface of degree 5. This surface has many remarkable properties and, in particular, it is mirror to itself. We construct the 3-dimensional big brother of this surface by considering the 3-dimensional Lyness map, which is an 8-periodic birational map. The variety we obtain is a special (non-$${\mathbb {Q}}$$ Q -factorial) affine Fano 3-fold of type $$V_{12}$$ V 12 , and we show that it is a self-mirror log Calabi–Yau 3-fold.

A graph-based interpretability method for deep neural networks

With the development of artificial intelligence, the most representative deep learning has been applied to various fields, which is greatly influencing human society. However, deep neural networks (DNNs) are still a black-box model, and the process how they make decisions internally is still difficult to understand and control. At the same time, DNNs take up more hardware resources, resulting in high energy consumption. Therefore, it is significant to study the characteristics of deep AI models and deeply understand the interactions between parameters within AI models so as to improve the interpretability of DNNs, optimize their structure and increase their computational efficiency. In this paper, we propose a graph-based interpretability method for deep neural networks (GIMDNN). The running parameters of DNNs are modeled as a graph by using a kernel function or the Graph Transformer Networks (GTN), where the nodes of the graph are obtained by dimensional mapping of the parameters of the DNNs, and the edges are calculated by the Gaussian kernel function. The generated graphs are classified by a graph convolutional network (GCN). The association relationship between the adjacent layers and the running mechanism of DNNs are analyzed, and the importance of the parameters of each layer in the DNNs for the final classification result can be obtained. Convolutional neural networks (CNNs) are one of the most representative models in DNNs. The proposed method is experimentally evaluated on the CNNs. The experimental results show that the proposed method can interpret the associations among the weight parameters as well as the correlation between two adjacent layers. Therefore, the DNNs for special tasks, such as portable applications, edge computing, and so on, can be customized, the number of parameters can be reduced. It is valuable to interpret the operation and principle of CNNs.

Energy-Efficient and Fading-Resistant Multi-Mode OFDM-IM With High Dimensional Mapping

Energy-Efficient and Fading-Resistant Multi-Mode OFDM-IM With High Dimensional Mapping

Kernel based quantum machine learning at record rate: Many-body distribution functionals as compact representations.

The feature vector mapping used to represent chemical systems is a key factor governing the superior data efficiency of kernel based quantum machine learning (QML) models applicable throughout chemical compound space. Unfortunately, the most accurate representations require a high dimensional feature mapping, thereby imposing a considerable computational burden on model training and use. We introduce compact yet accurate, linear scaling QML representations based on atomic Gaussian many-body distribution functionals (MBDF) and their derivatives. Weighted density functions of MBDF values are used as global representations that are constant in size, i.e., invariant with respect to the number of atoms. We report predictive performance and training data efficiency that is competitive with state-of-the-art for two diverse datasets of organic molecules, QM9 and QMugs. Generalization capability has been investigated for atomization energies, highest occupied molecular orbital-lowest unoccupied molecular orbital eigenvalues and gap, internal energies at 0K, zero point vibrational energies, dipole moment norm, static isotropic polarizability, and heat capacity as encoded in QM9. MBDF based QM9 performance lowers the optimal Pareto front spanned between sampling and training cost to compute node minutes, effectively sampling chemical compound space with chemical accuracy at a sampling rate of ∼48 molecules per core second.

A class of novel discrete memristive chaotic map

Since Chua introduced the memristor as the fourth basic circuit component, memristors and memristive chaotic maps have received great attention. In this paper, we present a class of novel memristive chaotic map by coupling the discrete memristor with the internal item in an original boundary function. Several examples are presented based on classical one dimensional (1D) and high dimensional (HD) chaotic maps, and numerical simulation results display their improved dynamical performance and chaos complexity. We analyze the influences of introducing the memristor on the chaotic map and the generality for designing discrete chaotic maps of the proposed memristive model. Particularly, with the newly emerging features of no fixed points and multistability, we can robustly control the output sequence by setting their initial-states, which accommodates to many arisen applications of chaotic systems. Furthermore, based on the proposed memristive chaotic map, we construct the hardware platform to acquire its attractors, and design the Pseudorandom Number Generator (PRNG) to explore its application prospects.

Hot working and microstructural response of ultrasonically fabricated 2 wt%ZrB2/AA7068 composite

Hot compression is an efficient and widely accepted route for optimizing the microstructural characteristics of metallic materials; thus, understanding hot deformation response is essential for producing the upgraded material. The present research investigated the hot working behaviour of ultrasonically fabricated in-situ 2 wt%ZrB2/AA7068 composite to obtain a dendrite-free microstructure after single-step compression. Compression response is studied in the broad thermomechanical range of T = 250–450 °C and ε̇=0.001-1 s−1. The true stress-true strain of the deformed specimens increases with an increase in the deformation rate and a decrease in temperature. The constitutive equation was established, which precisely predicted the flow behaviour of the material. A 3-dimensional workability map was plotted to study the workability with increasing strain. The workability map has displayed the highest power dissipation efficiency of 39 % in the domain of 433–450 °C, 0.04–0.01 s−1. Hot forging simulation through DEFORM-3D indicated a higher effective strain in the centre of the deformed specimens. EBSD IPF and GOS micrograph illustrated strained microstructure at lower temperatures ≤ 375 °C, ≤ 0.1 s−1, whereas fair recrystallization was observed at 375 °C, 0.001 ≤ ε̇≤ 0.01 s−1. The dynamic softening indicated the occurrence of DRV and CDRX. Additionally, the occurrence of PSN was also observed in the deformed microstructure. After hot working, the best-working region for a dendritic-free microstructure is recognized in 380–450 °C, 0.001–0.5 s−1. Microstructural evolution and workability map were in line with each other.

Microstructural and mechanical characteristics of hot worked homogenized AA7068 using 3D processing map and DEFORM-3D

AA7068 is classified as high strength aluminum alloy and is primarily utilized in wrought conditions which can be achieved with hot deformation. The process of hot deformation is a competent way of optimizing material properties; thus, understanding its deformation behavior in the wide range (250–450 °C, 10−3–100 s−1) is vital in processing a high-performance product. The true stress-true strain trend indicated its dependence on thermomechanical variables and precipitate size. The constitutive calculations accurately predicted the flow stress behavior. The kinetic rate calculations demonstrated that glide dislocation motion (with a value of n = 6.3) was observed during hot deformation. 3-dimensional processing map (PM) has revealed a progressive rise in efficiency (η) with increase in true strain. The PM analysis has successfully identified both stable and unstable working regions. Within the stable working region, a peak efficiency (η) of 54% was observed in the range of 347–359 °C and 10−3 s−1, 0.69 true strain. In, the stable working region, the microstructural characteristics demonstrated a notable increase in the dynamic softening depending on the process time and deformation temperature. At lower temperatures, the dynamic softening in the deformed specimens predominantly occurred through dynamic recovery (DRV), whereas at high temperatures, it facilitated by dynamic recrystallization (DRX). The DRX during deformation was observed to occur through continuous dynamic recrystallization (CDRX) and particle stimulated nucleation (PSN) mechanism. Hot forging finite element modeling (FEM) exhibited an uneven material flow with the peak effective strain occurring in the core of the specimen. Open forging in the optimum working conditions resulted in the highest tensile strength of 340 MPa, observed at a temperature of 450 °C and strain rate of 10−3 s−1.

Zero fluoroscopy catheter ablation for atrial fibrillation: a systematic review and meta-analysis.

Catheter ablation for atrial fibrillation (AF) is the most frequently performed cardiac ablation procedure worldwide. The majority of ablations can now be performed safely with minimal radiation exposure or even without the use of fluoroscopy, thanks to advances in 3-dimensional electroanatomical mapping systems and/or intracardiac echocardiography. The aim of this study was to conduct a meta-analysis to compare the effectiveness of zero fluoroscopy (ZF) versus non-zero fluoroscopy (NZF) strategies for AF ablation procedures. Electronic databases were searched and systematically reviewed for studies comparing procedural parameters and outcomes of ZF vs. NZF approaches in patients undergoing catheter ablation for AF. We used a random-effects model to derive the mean difference (MD) and risk ratios (RR) with a 95% confidence interval (CI). Our meta-analysis included seven studies comprising 1,593 patients. The ZF approach was found to be feasible in 95.1% of patients. Compared to the NZF approach, the ZF approach significantly reduced procedure time [mean difference (MD): -9.11 min (95% CI: -12.93 to -5.30 min; p < 0.01)], fluoroscopy time [MD: -5.21 min (95% CI: -5.51 to -4.91 min; p < 0.01)], and fluoroscopy dose [MD: -3.96 mGy (95% CI: -4.27 to -3.64; p < 0.01)]. However, there was no significant difference between the two groups in terms of total ablation time [MD: -104.26 s (95% CI: -183.37 to -25.14; p = 0.12)]. Furthermore, there was no significant difference in the acute [risk ratio (RR): 1.01, 95% CI: 1.00-1.02; p = 0.72] and long-term success rates (RR: 0.96, 95% CI: 0.90-1.03; p = 0.56) between the ZF and NZF methods. The complication rate was 2.76% in the entire study population and did not differ between the groups (RR: 0.94, 95% CI: 0.41-2.15; p = 0.89). The ZF approach is a feasible method for AF ablation procedures. It significantly reduces procedure time and radiation exposure without compromising the acute and long-term success rates or complication rates.

Development Diversity Study of Tourism Urban Area Function in Tomini Bay Coast-Indonesia

Purpose: This study aims to analyze the development diversity and land usage in coastal areas, especially development with a combination of three values (littoral, marine, anthropic) at Tomini Bay coast, Gorontalo City, in relation to Detailed Spatial Planning of Gorontalo City. Design/methodology/approach: This research uses Quantitative descriptive method using primary data and secondary data. The analysis technique is three and four dimensional mapping from the cumulative percentage calculation of each index to determine the tendency of concentration and distribution of various coastal land usage indices. Findings: The development by stakeholders and residents in each village shows a varied index value. This can be seen from the diversity index value. The highest diversity index value is Talumolo Village of 14.53, followed by North Leato Village of 12.08, South Leato Village of 11.34 and the lowest is Pohe Village of 7.17. This indicates a tendency of littoral area development by utilizing the coastal border area of Tomini Bay while the marine area is still limited to port construction to load and unload goods and passengers services. Research limitations/implications: The research is limited to the most of coastal cultivated areas in along the Tomini Bay that cannot accomodate many other interested phenomena. Practical implications: The strategy for regional development in coastal border areas should have technical provisions implementation for settlement development, especially for the intensity of building layout and environment. Social Implications: The city government should control the development of new buildings in coastal border area of Tomini Bay, providing protection to coastal border of Tomini Bay, and providing disaster protection buildings around the coastal border of Tomini Bay. Originality/value: Most of coastal cultivated along the Tomini Bay become main concern but still not researched for the technical provisions implementation for settlement development. This research examine the technical provisions implementation for settlement development

Caputo-Hadamard fractional chaotic maps

In this paper, we proposed a new fractional two dimensional trigonometric combined discrete chaotic mapping (2D-TCDCM) and a fractional 2-D Kawakami map within Caputo-Hadamard fractional difference. We observed the dynamic behaviours of the proposed Caputo-Hadamard fractional maps, including fractal graph, maximum lyapunov exponent, phase trajectory and randomness test. We illustrate the advantage of using Caputo-Hadamard fractional difference. As a conclusion, we get the condition of the proposed fractional map to behave chaotically with physics background.

The Equatorward Boundary of the Auroral Current System During Magnetic Storms

AbstractOur current knowledge of the geomagnetic poleward and equatorward boundary dynamics is limited, particularly, how deep those two latitudinal boundaries can extend into lower geomagnetic latitudes during magnetic storms. We want to understand the motion of the boundary because it is important in terms of the location and magnitude of the effects of geomagnetic disturbances associated with storms on the ground. In this study we derive spherical elementary ionospheric currents from ground magnetometer arrays covering North America and Greenland during six magnetic storms in 2015 and 2018. With two dimensional maps of the auroral region current, we select the equatorward boundary of the region 2 currents by‐eye and fit the boundary with an ellipse to derive the location of the equatorward boundary at magnetic midnight. We have obtained over 500 boundaries and find that the midnight boundary location varies between 45° and 66° magnetic latitude. We examine the influence of the interplanetary magnetic field (IMF), solar wind plasma, and geomagnetic indices on the location of the magnetic midnight equatorial boundary and find that the equatorial boundary location is best correlated with the IMF Bz, VBz, and the Sym‐H index. We demonstrate that as the Bz component becomes more negative, the magnitude of VBz increases, and the magnitude of the Sym‐H index increases, the magnetic midnight equatorial boundary shifts equatorward during periods of moderate to high geomagnetic activity.

Procedural Terrain Generation by Sampling a 2D Monochrom Perlin Noise Map in Unity

This article presents a study on procedural terrain generation using Perlin noise in the Unity game engine, building upon prior research and established techniques [1,2]. The objective of the this study is to create realistic and visually appealing landscapes by leveraging algorithmic generation [3]. By utilizing a two dimensional monochrome Perlin noise map, the algorithm generates terrains with organic features such as hills, valleys, and mountains [4]. The research employs the Unity game engine, which offers a wide range of tools and technologies for implementing procedural generation algorithms [5].&#x0D; The performance analysis conducted during this study yielded important insights. The execution time test revealed that the algorithm's execution time increased significantly with larger grid sizes, emphasizing the need to consider the scale and resolution of the terrains [6]. This finding highlights the trade-off between generating detailed terrains and the time required for the algorithm to complete its computations. Additionally, the memory usage test demonstrated a quadratic relationship between memory usage and grid size, indicating the necessity of efficient memory management [7] for generating higher-resolution terrains. Optimizing memory usage is crucial to avoid excessive consumption and ensure efficient resource utilization.&#x0D; These findings from the performance analysis provide valuable guidance for optimizing and refining the algorithm discussed in this article. Techniques such as algorithmic refinements, parallelization [8,6], and memory optimization strategies can be employed to reduce execution times and minimize memory overhead.&#x0D; By understanding the algorithm's performance characteristics and leveraging the insights gained from the analysis, developers can make informed decisions to generate visually compelling and diverse landscapes within the Unity game engine.

Characterization of right ventricular low voltage areas in patients with arrhythmogenic right ventricular cardiomyopathy

Abstract Funding Acknowledgements Type of funding sources: None. Background Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by fibrofatty replacement in the myocardium progressing from the epicardium towards the endocardium and affecting primarily the right ventricle (RV). Little data is available on the distribution of RV electrical abnormalities at the era of epicardial and high-resolution mapping. Purpose To evaluate the extent and distribution of RV epicardial and endocardial low voltage areas and their relationship with ECG abnormalities in ARVC patients. Methods Patients with a definite ARVC diagnosis according to the 2020 Task Force Criteria, who underwent ventricular tachycardia ablation between 2016 and 2022 with a high-density RV 3-dimensional electroanatomic mapping, were included. A custom RV segmentation dividing the RV into 10 segments from endocardial maps was used: anterior and lateral right ventricular outflow tract (RVOT); basal and mid inferior wall; apex; septum; basal anterolateral, basal inferolateral, mid anterolateral and mid inferolateral RV free wall (Figure). A standard definition of electrical scar was used (bipolar voltage ≤0.5 mV), and scar areas were manually delineated. Percentage of scar was defined by the ratio between scar area and the total segment area. ECG abnormal findings, such as epsilon wave and T-wave inversion in precordial leads, were measured before ablation procedure. Results Twenty-nine consecutive definite ARVC patients were included, among whose 24 had epicardial mapping in addition to endocardial mapping. When considering all segments, the epicardial scar (median:70%, interquartile range [IQR] 37-97%) was larger (p&amp;lt;0.0001) than the endocardial scar (9% [IQR] 0-32%). The higher percentage of epicardial scar was found in the basal inferolateral (100% [IQR] 73-100%), basal anterolateral (94% [IQR] 67-100%), RV free wall and lateral RVOT (89% [IQR] 48-100%) segments (Table). Transmural scar was observed mostly in basal inferolateral RV free wall (10 patients, 41%) and basal inferior wall (8 patients, 33%). Patients with major depolarization criteria had a higher percentage of epicardial and endocardial scar as compared to those with no or minor depolarization criteria (respectively 93% [IQR] 59-100% versus 62% [IQR] 28-89%, p&amp;lt;0.0001 and 17% [IQR] 0-42% versus 4% [IQR] 0-23%, p=0.001). There was no significant difference of the percentage of epicardial or endocardial scar in patients with and without major repolarization criteria (respectively 90% [IQR] 49-98% versus 84% [IQR] 43-100%, p=0.91 and 14% [IQR] 11-35% versus 16% [IQR] 0-41%, p=0.73). Conclusion In ARVC, the electrical abnormalities predominate in the basal epicardium. Patients with major depolarization criteria had a higher extent of epicardial and endocardial scar, but there was an association between scar extent and repolarization abnormalities.

Impact of 3-dimensional electroanatomic mapping systems on fluoroscopy reduction in catheter ablation of supraventricular tachycardia - then and now

Abstract Funding Acknowledgements Type of funding sources: None. Background Catheter ablation is an effective first-line treatment for symptomatic and recurrent supraventricular tachycardia (SVT). The advent of 3D electroanatomic mapping (EAM) has led to a reduction in fluoroscopy use and consequently lower radiation exposure for patients and staff during SVT ablation. Purpose The aims of this study are to demonstrate if the use of EAM during SVT ablation reduces fluoroscopy time (FT), and determine if further reductions in FT are observed longitudinally. We hypothesise that over time, with continued use and wider adoption of EAM, greater operator experience, and technological advancements in EAM, there will be further reductions in radiation exposure as estimated by FT. Methods All cases of atrioventricular nodal re-entry tachycardia (AVNRT), atrioventricular re-entry tachycardia (AVRT), and/or atrial tachycardia (AT) ablation between May 2011 to May 2022 at a tertiary centre were prospectively recruited. FT between the groups with and without EAM were compared. Within the EAM subset, the trend of FT across the years was also analysed. Results Over this 11-year period, there were 1758 cases of SVT ablation (565 without EAM; 1193 with EAM). Between the two groups, there were no significant differences (p &amp;gt; 0.05) in age, sex, history of structural heart disease and/or ischaemic heart disease, stereotaxis use, and diagnosis (AVNRT, AVRT, AT). Cases using EAM were more likely to have &amp;gt;1 SVT ablated during the procedure (0.04) and require intracardiac echocardiography (ICE) (p &amp;lt; 0.001). The use of EAM was associated with mean reductions in FT and dose area product (DAP) by 19.6 minutes and 18 581 mGy*cm2 respectively (both p &amp;lt; 0.001). EAM was also associated with a longer procedure time (mean +8.8 minutes, p &amp;lt; 0.001). There was no difference in radiofrequency application time between the two groups (p = 0.143). After controlling for potential confounding factors including age, sex, use of stereotaxis, use of ICE, type and number of SVT, history of prior ablation, and structural heart disease and/or ischaemic heart disease, we found over time (2011-2022), further reduction in FT was observed, with a mean reduction of 0.9 minutes year on year (p &amp;lt; 0.001). EAM was gradually adopted through the years with the number of cases per year plateauing after 2017. Between 2011-2017, there was a significant reduction in FT (mean of -1.1 minute year on year, p = 0.020), which was not observed from 2017 onwards (p = 0.088). The greatest reduction in FT was observed after the first year of adoption, with a mean reduction of 6.9 minutes between 2012-2013. Conclusion This demonstrates that use of EAM in SVT ablation reduces FT and fluoroscopy DAP. There was no incremental benefit observed after 6 years of EAM adoption likely related to operator experience. While there is increased interest in zero fluoroscopy SVT ablation, complementary use of fluoroscopy may still be necessary in select complex cases.