Evaluation of five algorithms in predicting the sublocalisation of right ventricular outflow tract arrhythmia (RVOTA) when compared to 3D electroanatomical mapping origin

Purpose To compare the predictive accuracy of five different algorithms as verified by successful ablation site using 3D electroanatomical non-contact mapping in patients with symptomatic and asymptomatic but high ventricular burden RVOT tachycardias. Methods 28 Consecutive patients admitted for radiofrequency catheter ablation for symptomatic and asymptomatic, but high ventricular burden idiopathic VPC were recruited for this study. All patients had previous failed or intolerant to beta-blocker and/or at least one class IC anti-arrhythmic agents, and they had normal left ventricular ejection fraction. All patients had documented monomorphic VPC with left bundle branch block morphology and an inferior axis. Concordance of the arrhythmia origin based on ECG algorithm and 3D mapping system site were further evaluated. Of the five algorithms, two algorithms with easy‐applicability and having a memorable design (Dixit and Joshi) and three algorithms with more complex and detailed design (Ito, Zhang, Pytkowski) were selected for comparisons. Results Assessment of the diagnostic accuracy showed that each of the five algorithms had only moderate accuracy, and the greatest accuracy was observed in the algorithm proposed by Pytkowski algorithm when assessed by a general cardiologist and Dixit algorithm when evaluated by the electrophysiologist. However, when the algorithms were compared for their accuracy, specificity, sensitivity, no significant differences were found (p = 0.99). Conclusions The ECG based algorithms for precise localising RVOTA origin simplify the mapping process, reduce the procedural and fluoroscopic time, and improve clinical outcomes, resulting in greater clinical utility. All the five published 12-lead ECG algorithms for ROTVA differentiation were similar in terms of the diagnostic accuracy, specificity, sensitivity and LRs.

European early experience with a novel 3D mapping system

Funding Acknowledgements Type of funding sources: None. Introduction Catheter navigation and 3-dimensional (3D) cardiac mapping are critical for successful electrophysiological ablation procedures. A novel 3D mapping system received CE Mark in July 2020. The system offers two imaging modalities: magnetic-based (VoXel) and impedance-based (NavX). Real-time display of 3D location and catheter movements is achieved via a magnetic field frame and magnetic sensors with supplemental impedance data when operating in VoXel mode or primarily via an impedance field generated from surface electrodes in NavX mode. To address limitations in data collection commonly experienced during 3D mapping, a new respiratory compensation algorithm, patient movement detection module, and metal compensation algorithm have been developed to enable consistent data collection throughout the full respiratory cycle even in challenging cases and lab environments. Purpose To examine the clinical utility and procedural characteristics associated with the use of this novel 3D mapping system among participating centers. Methods Procedural data was collected in cases utilizing the newly cleared mapping system during the initial evaluation phase in Europe. Procedural characteristics recorded included indication for mapping and ablation, rhythm mapped, chambers mapped, and procedure time. Results Procedural data was collected from over 250 cases across 12 European centers. A total of 12 indications for mapping and ablation were represented including de novo and redo atrial fibrillation (paroxysmal, persistent, long-standing persistent), ventricular tachycardia (ischemic, non-ischemic) or premature ventricular contraction, and supraventricular arrhythmias (typical and atypical atrial flutter, atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia). Over 70% of the cases were performed in VoXel mode. Impedance mode was mostly used in SVT cases or when the case was intended to be completed with minimal fluoroscopy. The most commonly mapped rhythms were sinus rhythm during voltage mapping and atrial tachycardia. The majority of cases (over 65%) were completed under conscious sedation; general anesthesia was used in 20% of the cases (15% not reported). The respiratory compensation algorithm was utilized in over 90% of the cases. For cases in which pre-procedural computed tomography or magnetic resonance imaging were available, operators indicated that the model shape was accurate when compared to pre-procedural imaging in 96% of the cases performed in VoXel mode. Conclusions Initial European experience with this novel 3D mapping system included a wide variety of arrhythmias in the atria and ventricles. This new mapping system offered operators the flexibility to tailor to specific procedure needs with two imaging modalities which were both widely utilized.

An improved window of interest for electroanatomical mapping of atrial tachycardia

Purpose Diagnosis of atrial tachycardia (AT) with 3D mapping system remains challenging due to fibrosis or previous ablation. This study aims to evaluate a new electroanatomical mapping annotation setting using a window of interest adjusted at the end of the P wave (WOIp wave) to identify the AT mechanism more accurately. Methods Twenty patients with successful ablation of left AT using navigation system CARTO3 were evaluated. Two maps for each patient were generated offline using either conventional settings of WOI (WOIconv.) or WOIp wave. Three investigators from two centres analysed the maps blindly. Results Mechanisms of AT were macroreentrant in 14/20 patients (70%) and focal in 6/20 (30%). WOIp wave resulted in a significant increase in the percentage of correct identification of the mechanism based on mapping alone (93.3 ± 13.7% vs 58.3 ± 33.9%; p = 0.0003) compared with WOIconv.. Diagnoses based on mapping were arrived at faster (27.8 ± 16.4 s vs 38.97 ± 13.64 s, respectively; p = 0.0231) and with a greater confidence in the diagnosis (confidence index 2.57 ± 0.45 vs 2.12 ± 0.45, respectively; p = 0.0024). With perimitral re-entry specifically “early meets late” was closer to the anatomical region of the mitral isthmus (15.9 ± 20.9 mm vs 48.77 ± 23.23 mm, respectively; p = 0.0028). Conclusions This study found that electroanatomical mapping acquisition with a window of interest set at the end of the P wave improves the ability to diagnose the arrhythmia mechanism based on the initial map. It is particularly beneficial in identifying area of interest for ablation in perimitral AT.

Visibility-Based Technologies and Methodologies for Autonomous Driving

The three main elements of autonomous vehicles (AV) are orientation, visibility, and decision. This chapter presents an overview of the implementation of visibility-based technologies and methodologies. The chapter first presents two fundamental aspects that are necessary for understanding the main contents. The first aspect is highway geometric design as it relates to sight distance and highway alignment. The second aspect is mathematical basics, including coordinate transformation and visual space segmentation. Details on the Light Detection and Ranging (Lidar) system, which represents the ‘eye’ of the AV are presented. In particular, a new Lidar 3D mapping system, that can be operated on different platforms and modes for a new mapping scheme is described. The visibility methodologies include two types. Infrastructure visibility mainly addresses high-precision maps and sight obstacle detection. Traffic visibility (vehicles, pedestrians, and cyclists) addresses identification of critical positions and visibility estimation. Then, an overview of the decision element (path planning and intelligent car-following) for the movement of AV is presented. The chapter provides important information for researchers and therefore should help to advance road safety for autonomous vehicles.

Multi-catheter cryotherapy compared with radiofrequency ablation in long-standing persistent atrial fibrillation: a randomized clinical trial

Aims Restoring sinus rhythm (SR) by ablation alone is an endpoint used in radiofrequency (RF) ablation for long-standing persistent atrial fibrillation (AF) but not with cryotherapy. The simultaneous use of two cryotherapy catheters can improve ablation efficiency; we compared this with RF ablation in chronic persistent AF aiming for termination to SR by ablation alone. Methods and results Consecutive patients undergoing their first ablation for persistent AF of >6 months duration were screened. A total of 100 participants were randomized 1:1 to multi-catheter cryotherapy or RF. For cryotherapy, a 28-mm Arctic Front Advance was used in tandem with focal cryoablation catheters. Open-irrigated, non-force sensing catheters were used in the RF group with a 3D mapping system. Pulmonary vein (PV) isolation and non-PV triggers were targeted. Participants were followed up at 6 and 12 months, then yearly. Acute PVI was achieved in all cases. More patients in the multi-catheter cryotherapy group were restored to SR by ablation alone, with a shorter procedure duration. Sinus rhythm continued to the last available follow-up in 16/49 patients (33%) in the multi-catheter at 3.0 ± 1.6 years post-ablation and in 12/50 patients (24%) in the RF group at 4.0 ± 1.2 years post-ablation. The yearly rate of arrhythmia recurrence was similar. Conclusion Multi-catheter cryotherapy can restore SR by ablation alone in more cases and more quickly than RF ablation. Long-term success is difficult to achieve by either methods and is similar with both.

Fluoroless and contrast-free catheter ablation without a lead apron in routine clinical practice

The technique of catheter ablation has been improved within the past few decades, especially by three-dimensional (3D) mapping system. 3D mapping system has reduced radiation exposure but ablation procedures still require fluoroscopy. Our previous study showed the safety and efficacy of catheter ablation based on intracardiac echogram combined with CARTOSOUND/CARTO3 system, however fluoroscopy use for an average of 16 min is required for this procedure. The present study was aimed to reduce radiation exposure to zero and establish a radiation free catheter ablation method with the goal of utilizing it in routine clinical practice. We conducted single center, retrospective study during 2019 April to 2020 February. Consecutive 76 patients were enrolled. In the first 18 cases, the previously reported procedure (CARTOSOUND/CARTO3 method) was used. The remaining 58 cases were transitioned to fluoroless catheter ablation. The procedure time, success rates and complication rates were analyzed. Not only AF patients but atrial flutter (AFL), paroxysmal supraventricular tachycardia (PSVT) and ventricular arrhythmia patients were included. Catheter positioning, catheter visualization and collecting the geometry of each camber of the heart were conducted by using contact force and ICE based geometry on CARTO system without either prior computed tomography (CT) or magnetic resonance image (MRI). In fluoroless group, all catheter ablations were successfully performed without lead aprons. No complications occurred in either group. There were no significant differences in procedure time in any type of procedure (Total procedure time Fluoro-group; 149 ± 51 min vs. Fluoroless-group; 162 ± 43 min, N.S.), (PSVT 170 ± 53 min vs. 162 ± 29 min, N.S.), (AFL 110 ± 70 min vs. 123 ± 43 min, N.S.), (AF 162 ± 43 min vs. 163 ± 32 min, N.S.). The total radiation time was reduced to zero in fluoroless group. Catheter ablation with ICE and 3D mapping system guide without fluoroscopy could be safely performed with a high success rate, without any prior CT/MRI 3D images. Radiation was reduced completely for patients and staff, negating the need for protective wear for operators.