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Background:Catheter ablation is a safe and effective therapy for the treatment of supraventricular tachycardia in children. Current improvements in technology have allowed progressive reduction in radiation exposure associated with the procedure. To assess the impact of three-dimensional mapping, we compared acute procedural results collected from the Catheter Ablation with Reduction or Elimination of Fluoroscopy registry to published results from the Prospective Assessment after Pediatric Cardiac Ablation study.Methods:Inclusion and exclusion criteria from the Prospective Assessment after Pediatric Cardiac Ablation study were used as guidelines to select patient data from the Catheter Ablation with Reduction or Elimination of Fluoroscopy registry to compare acute procedural outcomes between cohorts. Outcomes assessed include procedural and fluoroscopy exposure times, success rates of procedure, and complications.Results:In 786 ablation procedures, targeting 498 accessory pathways and 288 atrioventricular nodal reentrant tachycardia substrates, average procedural time (156.5 versus 206.7 minutes, p < 0.01), and fluoroscopy time (1.2 versus 38.3 minutes, p < 0.01) were significantly shorter in the study group. Success rates for the various substrates were similar except for manifest accessory pathways which had a significantly higher success rate in the study group (96.4% versus 93.0%, p < 0.01). Major complication rates were significantly lower in the study group (0.3% versus 1.6%, p < 0.01).Conclusions:In a large, multicentre study, three-dimensional systems show favourable improvements in clinical outcomes in children undergoing catheter ablation of supraventricular tachycardia compared to the traditional fluoroscopic approach. Further improvements are anticipated as technology advances.

Three-dimensional mapping is an essential component of autonomous Micro Aerial Vehicle (MAV) navigation. The paper focuses on the 3D spatial representation method of MAV to overcome the collision problem caused by soft constraints, control error, and planning with the center of mass by inflating the occupancy grid map. A fast incremental inflated map construction method is proposed, which reduces the time-consumption caused by the increase of map range and inflated size. The method focuses on areas of the map that occupied state changes and introduces two arrays that record newly appearing and disappearing obstacles. Then, a series of breadth-first search algorithms are used to traverse the parts of the inflated map that need local modification to update the inflated map. Moreover, a sliding map model is designed based on the MAV position, which is suitable for large-range autonomous flight. The effectiveness of the proposed approach is verified with simulated and actual flight data. The proposed method takes about 3 ms to construct the inflated map with a local update range of 16 m × 16 m × 6 m.

A 51-year-old man, who had a history of open heart surgery for corrected transposition of great arteries, presented with palpitation due to atrial tachycardia. A propagation map using three-dimensional electroanatomical mapping (CARTO3) showed atrial flutter and underwent linear ablation successfully. This case highlights the difficulty of diagnosis before mapping following a complicated cardiac operation and the usefulness of three-dimensional mapping.

The majority of electrophysiologists routinely use fluoroscopy (FLUORO) during ablation procedures for common arrhythmias despite the known complications of radiation exposure and protective lead use. This study assessed the safety of catheter ablation (CA) with FLUORO versus without FLUORO (SANS FLUORO) in patients with the following common arrhythmias: atrial fibrillation (AF), atrial flutter, supraventricular tachycardia, and ventricular tachycardia. A total of 1,258 CA procedures were performed in 816 consecutive patients over a 53-month period (SANS FLUORO CA: 609 patients; FLUORO CA: 209 patients). The secondary outcome was the efficacy of AF ablation in FLUORO versus SANS FLUORO patients. Ultimately, there was no statistically significant difference found concerning the safety of CA in the SANS FLUORO and FLUORO groups in terms of procedure time, vascular complications, tamponade, stroke, or death. FLUORO patients had markedly increased FLUORO time, increased radiation exposure, and increased dose-area product (all p < 0.0001). AF development after SANS FLUORO CA of AF was not different from that after FLUORO CA regardless of the pulmonary vein isolation (PVI) modality used (cryoablation versus radiofrequency) at 24 months (p = 0.21). Additionally, women fared just as well as men after CA ablation for AF. At 36 months, 58% of SANS FLUORO AF device patients were free from AF. As such, SANS FLUORO CA of common arrhythmias appears to be as safe as FLUORO CA but with a markedly reduced level of radiation exposure. Also, SANS FLUORO CA remains as effective as FLUORO CA in the prevention of AF for up to 24 months.

BackgroundDenis and Ferguson et al.’s three-column spinal theory has been widely accepted and applied. However, this three-column theory was proposed based solely on observation and experience without thorough documented data and analysis. The aim of this study was to analyze and improve Denis and Ferguson et al.’s three-column spinal theory to propose a novel three-column concept in epidemiology, morphology and biomechanics.MethodsA retrospective analysis of the computed tomography imaging data of patients with a diagnosis of T11-L5 vertebral fractures was conducted between February 2010 and December 2018. Three-dimensional (3D) distribution maps of fracture lines of all subjects were obtained based on 3D mapping techniques. In addition, a 25-year-old health male volunteer was recruited for the vertebral finite element force analysis.ResultsThe present study enrolled 459 patients (age: 48 ± 11.42 years), containing a total of 521 fractured vertebrae. The fracture lines peaked in the upper and the outer third sections of the vertebra, starting from the anterior part of the vertebral pedicles in 3-D maps. Regarding flexion and extension of the spine, the last third of the vertebral body in front of the spinal canal was one main stress center in the finite element analysis. The stress on the vertebral body was greater in front of the pedicles in the lateral bending.ConclusionThe study reveals that the posterior one-third of the vertebral body in front of the spinal canal and the posterior one-third of the vertebral body in front of the pedicle are very different in terms of fracture characteristics and risks to spinal canal (3D maps and stress distributing graphs), therefore, they should be classified as different columns. We provide strong evidence that Su’s three-column theory complies with the characteristics of vertebral physiological structure, vertebral fracture, and vertebral biomechanics.Graphical abstract

Atypical left atrial flutters present following atrial fibrillation ablation have been well-documented in the literature. These arrhythmias are known to be difficult to localize and ablate. An atypical flutter with an alternating activation pattern in the coronary sinus, however, is unusual and has rarely been discussed. In this case report, we describe the use of high-density three-dimensional anatomic mapping to successfully localize and terminate an atypical flutter with an alternating atrial activation pattern in the coronary sinus.

Summary Background Catheter ablation is widely used to treat symptomatic atrial fibrillation (AF) refractory to drug therapy; and can be facilitated by a number of different techniques. Aims To evaluate our performance as a new centre for AF ablation and to evaluate the efficacy of different AF ablation techniques. Methods We employed three techniques in AF ablations; the three-dimensional (3D) mapping approaches (CARTO® or Ensite NavX®) or multielectrode catheter duty-cycled radiofrequency ablation (pulmonary vein ablation catheter [PVAC®]). The immediate restoration of sinus rhythm was considered as acute success; while success at 6 months was determined by the maintenance of sinus rhythm on Holter monitoring. Results Between March 2008 and March 2010, 109 patients underwent AF ablations (mean age: 58 years; 72% male). Six-month success rates did not differ significantly between CARTO and NavX (40% vs 38%; P = 0.81), but the PVAC group achieved greater success than the two 3D-mapping groups combined (68% vs 39%; P = 0.004). Paroxysmal AF patients demonstrated greater 6-month success than persistent AF patients (P = 0.005); and although the ratio of paroxysmal to persistent AF patients was slightly higher among the PVAC group, logistic regression confirmed PVAC and paroxysmal AF as predictors of success. Single-procedure success at 6 months was 48%. Including redo-ablations, some performed beyond the study period, our overall success rate at 6 months was 65%. Four patients experienced complications, but there were no deaths. Conclusion Despite being a new centre with relative inexperience, we achieved success rates comparable to those of established tertiary centres. PVAC performed significantly better than the two 3D-mapping approaches.

The purpose of this study is to examine a normal conduction pathway of the left atrium. During pulmonary vein isolation using a three-dimensional mapping system, we observed the characteristics of the conduction pattern. Subjects consisted of 15 patients with paroxysmal atrial fibrillation (mean age, 62.8 ± 8.4 years). Left atrial activation conduction begins in the interatrial septum, and moves toward the peak of the ridge between the left atrial appendage and left pulmonary vein. In coronary sinus or appendage pacing, conduction was in the opposite direction at the same location. The mean conduction velocity in this area was 2.03 ± 0.43 m/s. Features of decrement conduction were not present. Anatomical position of the appendage differed greatly between patients. A detailed observation using the inner-cavity view of a three-dimensional mapping system also showed that the peak of the ridge reached the center of the roof.

This thesis investigates the problem of reliably estimating attitude from panoramic imagery in cluttered environments. Accurate attitude is an essential input to the stabilisation systems of autonomous aerial vehicles. A new camera system which combines a CCD camera, UltraViolet (UV) filters and a panoramic mirror-lens is designed. Drawing on biological inspiration from the Ocelli organ possessed by certain insects, UV filtered images are used to enhance the contrast between the sky and ground and mitigate the effect of the sun. A novel method for real–time horizon-based attitude estimation using panoramic image that is capable of estimating an aircraft pitch and roll at a low altitude in the presence of sun, clouds and occluding features such as tree, building, is developed. Also, a new method for panoramic sky/ground thresholding, consisting of a horizon– and a sun–tracking system which works effectively even when the horizon line is difficult to detect by normal thresholding methods due to flares and other effects from the presence of the sun in the image, is proposed. An algorithm for estimating the attitude from three–dimensional mapping of the horizon projected onto a 3D plane is developed. The use of optic flow to determine pitch and roll rates is investigated using the panoramic image and image interpolation algorithm (I2A). Two methods which employ sensor fusion techniques, Extended Kalman Filter (EKF) and Artificial Neural Networks (ANNs), are used to fuse unfiltered measurements from inertial sensors and the vision system. The EKF estimates gyroscope biases and also the attitude. The ANN fuses the optic flow and horizon–based attitude to provide smooth attitude estimations. The results obtained from different parts of the research are tested and validated through simulations and real flight tests.

Anastasios John Kanellopoulos,1,2 George Asimellis1 1LaserVision.gr Eye Institute, Athens, Greece; 2Department of Ophthalmology, New York University Medical School, New York, NY, USA Purpose: To investigate epithelial thickness-distribution characteristics in a large group of keratoconic patients and their correlation to normal eyes employing anterior-segment optical coherence tomography (AS-OCT).Materials and methods: The study group (n=160 eyes) consisted of clinically diagnosed keratoconus eyes; the control group (n=160) consisted of nonkeratoconic eyes. Three separate, three-dimensional epithelial thickness maps were obtained employing AS-OCT, enabling investigation of the pupil center, average, mid-peripheral, superior, inferior, maximum, minimum, and topographic epithelial thickness variability. Intraindividual repeatability of measurements was assessed. We introduced correlation of the epithelial data via newly defined indices. The epithelial thickness indices were then correlated with two Scheimpflug imaging-derived AS-irregularity indices: the index of height decentration, and the index of surface variance highly sensitive to early and advancing keratoconus diagnosis as validation.Results: Intraindividual repeatability of epithelial thickness measurement in the keratoconic group was on average 1.67 µm. For the control group, repeatability was on average 1.13 µm. In the keratoconic group, pupil-center epithelial thickness was 51.75±7.02 µm, while maximum and minimum epithelial thickness were 63.54±8.85 µm and 40.73±8.51 µm. In the control group, epithelial thickness at the center was 52.54±3.23 µm, with maximum 55.33±3.27 µm and minimum 48.50±3.98 µm epithelial thickness. Topographic variability was 6.07±3.55 µm in the keratoconic group, while for the control group it was 1.59±0.79 µm. In keratoconus, topographic epithelial thickness change from normal, correlated tightly with the topometric asymmetry indices of IHD and ISV derived from Scheimpflug imaging.Conclusion: Simple, OCT-derived epithelial mapping, appears to have critical potential in early and advancing keratoconus diagnosis, confirmed with its correlation with established Scheimpflug-derived asymmetry topometric indices. Keywords: anterior-segment optical coherence tomography, early and advancing keratoconus, epithelial thickness imaging, novel corneal epithelial thickness-asymmetry indices, three-dimensional mapping, Scheimpflug imaging based Pentacam, topographic keratoconus grading, index of surface variance, index of height decentration