P955Non-invasive mapping: what is the minimal number of electrodes needed to obtain a good spatial resolution of the activation map?

Abstract Introduction and aims The 12-lead ECG is highly inaccurate for localization of the site of origin of supraventricular and ventricular arrhythmias. Non-invasive mapping systems (ECGI) based on a high number of electrodes recording the electrical activity on the surface of the torso have already proven good accuracy for mapping different arrhythmic substrates. The aim of this study was to assess what is the minimal number of leads needed to obtain a precise mapping with the ECGI. Methods This study enrolled 14 patients (9 male, median age 50 (44-58) years) referred to our center for catheter ablation of premature ventricular contractions (PVC). Patients underwent pre-procedural ECGI using the epicardial and endocardial mapping system . This system uses the DICOM images from contrast computed tomography of the heart and up to 28 adhesive electrodes with 8 leads each, adding up to 224 body-surface leads. All patients underwent invasive electroanatomical mapping and ablation with the magnetic navigation system. We analysed the number of recording leads used to construct the non-invasive activation map of the PVCs and the accuracy and the spatial resolution of the map when comparing to the invasive map. We then reprocessed the exam, using progressively less leads until we only left the leads placed in the standard 12 lead ECG positions and evaluated the concordance with the invasive map as well as the spatial resolution. We considered an earliest activation site (EAS) area of 1 cm2 a good spatial resolution and using a ROC curve we calculated the minimal number of leads necessary to obtain a good spatial resolution. Results The median number of electrodes used for the initial map was 170 (138-177). Concordance between non-invasive and invasive site of origin occurred in 11 out of 14 patients. The results are presented in the Table. The minimal number of electrodes to have a good spatial resolution was 100. The area of EAS was significantly lower when using more than 100 leads, respectively 0.65 (0.5-1) cm2 versus 3 (1.6-5) cm2, p < 0.001. Conclusions The minimal number of leads to achieve a good spatial resolution was high. Reducing the number of leads resulted in a significant decrease in spatial resolution and a lower concordance rate. ECGI data Number of adhesive electrodes Median number of leads Amycard/Carto concordance Median area of EAS in the ECGI (cm2) Maximal nº electrodes 170 (138-177) 11/14 0.64 (0.5-0.9) 12 electrodes 76 (61-80) 11/14 1.6 (1.4-2.6) 6 electrodes (2 Ant, 2 Lat ,2 Post) 38 (32-44) 9/14 4.3 (3.2-5.4) 12 leads 12 0/14 - Ant anterior; Lat: lateral; Post: posterior; EAS: early activation site. Abstract Figure. Area of EAS according to the N of leads

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P5702Non-invasive epicardial and endocardial mapping in patients with idiopathic right ventricular outflow tract premature ventricular contractions: new insights into arrhythmia substrate

European Heart Journal ◽

10.1093/eurheartj/ehz746.0644 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

A L Parreira ◽

P Carmo ◽

P Adragao ◽

J Pinho ◽

R Jeronimo ◽

...

Keyword(s):

Right Ventricular ◽

Right Ventricular Outflow Tract ◽

Ventricular Outflow Tract ◽

Outflow Tract ◽

Control Group ◽

P Value ◽

Premature Ventricular Contractions ◽

Non Invasive ◽

Endocardial Mapping ◽

Unipolar Electrograms

Abstract Background It has been accepted for years that idiopathic premature ventricular contractions (PVCs) with origin in the right ventricular outflow tract (RVOT) are benign. They are thought to result from triggered activity and most studies do not describe abnormal findings during electroanatomical mapping Dispersion of ventricular repolarization is associated with the susceptibility to ventricular arrhythmias and may indicate the presence of diseased myocardium. The activation recovery interval (ARI) has been used as a surrogate measure of ventricular action potential duration and refractory period. Purpose The aim of this study was to use the new non-invasive epicardial and endocardial mapping system (NEES) to study patients with RVOT PVCs in order to evaluate the ARI in the epicardium of RVOT during sinus rhythm (SR). Methods Non-invasive mapping was performed with the NEES, based on body surface electrocardiograms of a maximum of 224 electrodes and computed tomography imaging data. Unipolar electrograms were reconstructed on the epicardial and endocardial surfaces. Patients were excluded if they had structural heart disease, previous ablation or conduction abnormalities. ARI was defined as the interval between times of minimum derivative of the QRS and the maximum derivative of the T wave in the unipolar electrograms. We evaluated the ARI map in patients with RVOT PVCs and in a control group of patients without PVCs (Figure). We assessed the maximum value of ARI (Max ARI), the minimum value of ARI (Min ARI) and the difference between the Max ARI and the Min ARI (Diff ARI). Results We studied 8 patients with RVOT PVCs and 8 patients without PVCs. The results are presented in the table. Demographic and NEES data RVOT PVCs (n=8) Control (n=8) P value* Demographic data Age in years, median (IQR) 53 (48–65) 59 (52–67) 0.536 Male gender, n (%) 4 (50) 6 (75) 0.608 NEES data Max ARI in msec, median (IQR) 285 (236–331) 228 (197–298) 0.195 Min ARI in msec, median (IQR) 176 (138–192) 216 (185–255) 0.161 ARI diff in msec, median (IQR) 111 (83–147) 15 (4–34) <0.0001 NEES map Conclusion In this group of patients we found a significantly higher dispersion of the ARI measurements through the epicardium of the RVOT in patients with PVCs in comparison with patients without PVCs.

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Stability and performance of the EnSite Precision cardiac mapping system for electrophysiology mapping and ablation procedures: results from the EnSite Precision observational study

European Heart Journal ◽

10.1093/ehjci/ehaa946.0610 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

D Lin ◽

B Glover ◽

J Colley ◽

B Thibault ◽

C.M Steinberg ◽

...

Keyword(s):

Observational Study ◽

Real World ◽

Cardiac Electrophysiology ◽

Median Number ◽

System Stability ◽

Cardiac Mapping ◽

Average Force ◽

Mapping System ◽

Respiratory Change ◽

Electrophysiology Mapping

Abstract Background The EnSite Precision™ Cardiac Mapping System is a catheter navigation and mapping system capable of displaying the three-dimensional (3D) position of conventional and sensor enabled electrophysiology catheters, as well as displaying cardiac electrical activity as waveform traces and dynamic 3-D maps of cardiac chambers. Objective The EnSite Precision™ Observational Study was designed to quantify and characterize the use of the EnSite Precision™ Cardiac Mapping System for mapping and ablation of cardiac arrhythmias in a real-world environment and to evaluate procedural and subsequent clinical outcomes. Methods 1065 patients were enrolled at 38 centers in the U.S. and Canada between 2017–2018. Eligible subjects were adults undergoing a cardiac electrophysiology mapping and radiofrequency ablation procedures using the EnSite Precision™ System. Results Of 989 patients who completed the protocol, a geometry was created in 936 (94.7%). Most initial maps were created using Automap (n=545, 67.0%) or a combination of Automap and manually mapping (n=151, 18.6%). Median time to create an initial map was 9.0 min (IQR 5.0–15.0), with a median number of used mapping points per minute of 92.7 (IQR 30.0–192.0). During ablation, AutoMark was used in 817 (82.6%) of procedures. The most frequent metrics for lesion color were Impedance Drop or Impedance Drop Percent (45.5% combined), time (23.9%) and average force (14.2%). At Canadian sites where LSI was an option, it was used as the color metric in 87 (45.8%) of cases (10.6% overall). The EnSite System was stable throughout 79.7% (n=788 of 989) of procedures. Factors affecting stability were respiratory change (n=88 of 989, 8.9%), patient movement (n=73, 7.4%), CS Positional Reference dislodgement (n=32, 3.2%), and cardioversion (n=19, 1.9%). Conscious sedation was used in 189 (19.1%) of patients. Acute success was reached based on the pre-defined endpoints for the procedure in 97.4% (n=963) of cases. Conclusion In a real-world study analysis, the EnSite Precision™ mapping system was associated with a high prevalence of acute procedural success, low mapping times, and high system stability. Funding Acknowledgement Type of funding source: None

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A method of precise misorientation determination

Journal of Applied Crystallography ◽

10.1107/s0021889803015905 ◽

2003 ◽

Vol 36 (6) ◽

pp. 1319-1323 ◽

Cited By ~ 5

Author(s):

A. Morawiec

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Spatial Resolution ◽

Standard Procedure ◽

Good Spatial Resolution ◽

Transmission Electron ◽

Order Of Magnitude ◽

Achievable Accuracy ◽

Better Than

A method that improves the accuracy of misorientations determined from Kikuchi patterns is described. It is based on the fact that some parameters of a misorientation calculated from two orientations are more accurate than other parameters. A procedure which eliminates inaccurate elements is devised. It requires at least two foil inclinations. The quality of the approach relies on the possibility to set large sample-to-detector distances and the availability of good spatial resolution of transmission electron microscopy. Achievable accuracy is one order of magnitude better than the accuracy of the standard procedure.

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NEMA NU4-2008 Performance Evaluation of Albira: A Two-Ring Small-Animal PET System Using Continuous LYSO Crystals

Open Medicine Journal ◽

10.2174/1874220301603010012 ◽

2016 ◽

Vol 3 (1) ◽

pp. 12-26 ◽

Cited By ~ 6

Author(s):

Malgorzata Z. Pajak ◽

David Volgyes ◽

Sally L. Pimlott ◽

Carlos C. Salvador ◽

Antonio S. Asensi ◽

...

Keyword(s):

Spatial Resolution ◽

Small Animal Imaging ◽

Small Animal ◽

Axial Direction ◽

Small Animal Pet ◽

Performance Review ◽

Good Spatial Resolution ◽

Positron Emission ◽

Animal Images ◽

Pet System

Goals:This paper presents the performance review based on a dual-ring Positron Emission Tomography (PET) scanner being a part of Bruker Albira: a multi-modal small-animal imaging platform. Each ring of Albira PET contains eight detectors arranged as octagon, and each detector is built using a single continuous lutetium-yttrium oxyorthosilicate crystal and multi-anode photo multiplier tube. In two-ring configuration, the scanner covers 94.4 mm in axial- and 80´80 mm in trans-axial direction, which is sufficient to acquire images of small animals (e.g.mice) without the need of moving the animal bed during the scan.Methods:All measurements and majority of data processing were performed according to the NEMA NU4-2008 standard with one exception. Due to the scanner geometry, the spatial resolution test was reconstructed using iterative algorithm instead of the analytical one. The main performance characteristics were compared with those of the other PET sub-systems of tri-modal small-animal scanners.Results:The measured spatial resolution at the centre of the axial field of view in radial, tangential and axial directions was 1.72, 1.70 and 2.45 mm, respectively. The scatter fraction for the mouse-like phantom was 9.8% and for the rat-like phantom, 21.8%. The maximum absolute sensitivity was 5.30%. Finally, the recovery co-efficients for 5, 4, 3, 2, 1 mm diameter rods in image quality phantom were: 0.90, 0.77, 0.66, 0.30 and 0.05, respectively.Conclusion:The Bruker Albira is a versatile small-animal multi-modal device that can be used for variety of studies. Overall the PET sub-system provides a good spatial resolution coupled with better-than average sensitivity and the ability to produce good quality animal images when administering low activities.

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Abstract 16807: Role of Rotor Activation Within the Pulmonary Vein as the Driving Sources for Atrial Fibrillation: Three-dimensional Analysis using a Non-contact Mapping System

Circulation ◽

10.1161/circ.132.suppl_3.16807 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Hiroshige Yamabe ◽

Hisanori Kanazawa ◽

Tadashi Hoshiyama ◽

Miwa Ito ◽

Shozo Kaneko ◽

...

Keyword(s):

Atrial Fibrillation ◽

Pulmonary Vein ◽

Three Dimensional ◽

Recording Site ◽

Contact Mapping ◽

Proximal Half ◽

Mapping System ◽

Endocardial Mapping ◽

Activation Sequence

Background: It has been suggested rotor which is located within the pulmonary vein (PV) acted as the driving sources of atrial fibrillation (AF). However, it has never been confirmed whether or not the rotor exists within PV in human. Objectives: We analyzed the activation sequence within the PV during AF and examined how the PV acted as the driving sources of AF. Methods: Selective endocardial mapping of left superior PV (LSPV) was performed during AF in 11 paroxysmal AF patients using a non-contact mapping system (EnSite 3000). Presence of rotor activation was defined when the circular activation around the functional block line once completed its whole reentrant activation. We analyzed the relation between the pivoting activation and the rotor activation. To define the preferable site of rotor and pivoting activation, we also analyzed the relation between the location of rotor and pivoting activation and region of the complex fractionated electrogram (CFE) recording site. Results: Rotor activation was observed with a mean number of 4.6±3.6 times/sec. CFE was observed at the roof (n=5), ridge (n=11) and carina (n=7) of the proximal half of LSPV with a mean area of 9.1±3.4 cm2. The number of rotor activation observed at the CFE area was significantly higher than that at the non-CFE area (4.1±3.9 vs. 0.7±1.2 times/sec, p=0.025). Total frequency of pivoting activation was 37.0±14.7 times/sec. Pivoting activation involved in the rotor activation was significantly lower than that not involved in the rotor activation (8.8±8.1 vs. 27.7±15.8 times/sec, p=0.0116). Regarding the CFE area, pivoting activation involved in the rotor activation was also significantly lower than that not involved in the rotor activation (8.4±8.2 vs. 24.1±12.0 times/sec, p=0.0105). However, there was no difference between the frequencies of pivoting activation with and without rotor activation in the non-CFE area (1.0±2.0 vs. 3.6±6.1 times/sec, p=NS). Conclusions: Rotor activation was observed at the proximal portion of the LSPV coincided with the location of CFE area. However, most of pivoting activation was not involved in the rotor activation. These suggest that AF was driven by the other meandering propagation associated with frequent non-stable pivoting activation over the CFE area.

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Abstract 2919: Do Premature Ventricular Contractions Play a Role in the Etiologic Subtypes of Ischemic Stroke?

Stroke ◽

10.1161/str.43.suppl_1.a2919 ◽

2012 ◽

Vol 43 (suppl_1) ◽

Author(s):

JUN LEE ◽

Na-Young Kim

Keyword(s):

Risk Factors ◽

Ischemic Stroke ◽

Cryptogenic Stroke ◽

Holter Monitoring ◽

Median Number ◽

Large Artery ◽

Vessel Occlusion ◽

Premature Ventricular Contractions ◽

Ordinal Logistic Regression Analysis ◽

The Relationship

Background The relationship between stroke and non-atrial fibrillation cardiac arrhythmias remains unclear. Frequent premature ventricular contractions (PVCs) are associated with impaired ventricular relaxation and may increase the risk of clot formation and subsequent embolization. This study investigated the relationship between frequency of PVCs and etiologic subtypes of ischemic stroke. Methods Consecutive ischemic stroke patients admitted within 7 days of onset who underwent 24-hour Holter monitoring were enrolled (n=451). Subtypes of ischemic stroke were defined according to the SSS-TOAST classification as Large artery atherosclerosis (LAD), cardioembolic stroke (CE), small vessel occlusion (SVO), other causes (OC), and cryptogenic stroke (CS). Risk factors, demographic information, and 24-hour Holter recordings were compared between the subtypes of ischemic stroke. Results There were 182 women and 269 men (191 LAD, 90 CE, 93 SVO, 13 OC, 64 CS), with a mean age of 66 years (median 68). PVCs were seen in 305 patients (67.5%) on 24-hour Holter monitoring (median 3, IQR 0-48). CE had a higher median number of PVCs (median 24, IQR 0-258) than LAD (median 2, p=0.01), SVO (median 1, p<0.001), OC (median 0, p=0.013), and CS (median 4, p=0.2). The proportions of frequent PVCs (>50 in a 24-hour Holter monitoring) were higher in CE (43.3%) compared with the other groups (20.9% in LAD, 15.1% in SVO, 15.4% in OC, and 23.4% in CS; p<0.001). Compared with the SVO, the upper 3 quartiles of PVCs were associated with CE (OR 2.93; 95% CI, 1.69 to 5.06) and CS (OR 1.86; 95% CI, 1.07 to 3.2) in ordinal logistic regression analysis after adjustment for traditional risk factors. Conclusions The number of PVCs detected by 24-hour Holter monitoring is associated with CE and CS. The presence of high frequency of PVC may help in stratifying patients with different stroke subtypes, particularly embolic stroke. The role of these arrhythmias as a risk marker for ischemic stroke deserves further investigation.

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Methodologies on the Enhanced Spatial Resolution of Non-Invasive Optical Brain Imaging: A Review

IEEE Access ◽

10.1109/access.2019.2939475 ◽

2019 ◽

Vol 7 ◽

pp. 130044-130066 ◽

Cited By ~ 1

Author(s):

Zeshan Shoaib ◽

Muhammad Ahmad Kamran ◽

Malik Muhammad Naeem Mannan ◽

Myung Yung Jeong

Keyword(s):

Brain Imaging ◽

Spatial Resolution ◽

Non Invasive

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Present and Emerging Techniques for Materials Microanalysis

MRS Proceedings ◽

10.1557/proc-69-3 ◽

1986 ◽

Vol 69 ◽

Cited By ~ 1

Author(s):

C. R. Helms

Keyword(s):

Quantitative Analysis ◽

Spatial Resolution ◽

High Sensitivity ◽

Characterization Methods ◽

Good Spatial Resolution ◽

Accurate Quantitative Analysis ◽

Significant Extension ◽

Minimal Damage ◽

A New Technique ◽

The Cost

AbstractAlthough classical materials characterization methods have existed for many years, modern microanalytical techniques had their start just over twenty years ago. In this paper, I will discuss some of the common techniques available today including AES, XPS, or ESCA, RBS, SIMS, and EDAX. A comparison of the key capabilities and limitations will be given including sensitivity, spatial resolution, quantitative analysis, nondestructive testing, chemical state determination, and analysis speed. It is clear that the reason each of these techniques still exists as commercial instrumentation is that each provides a unique set of capabilities, but also a unique set of limitations. To become viable in the materials analysis arena, a new technique must offer a significant extension of the capabilities already available but not at the cost of too severe a set of limitations. Examples would be the development of tools that offer both high sensitivity with accurate quantitative analysis, or good spatial resolution with high sensitivity, or minimal damage but good spatial resolution, etc. A number of papers in this volume will describe the details of these emerging technologies which provide advances in these areas; and I will attempt here to put a number of these new developments in perspective with regard to the more commonplace techniques available.

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