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Voltage Mapping

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https://www.readbyqxmd.com/read/28641242/arrhythmia-mechanism-and-scaling-effect-on-the-spectral-properties-of-electroanatomical-maps-with-manifold-harmonics
#1
Margarita Sanroman-Junquera, Inmaculada Mora-Jimenez, Arcadi Garcia-Alberola, Antonio J Caamano, Beatriz Trenor, Jose Luis Rojo-Alvarez
Spatial and temporal processing of intracardiac electrograms provides relevant information to support the arrhythmia ablation during electrophysiological studies. Current Cardiac Navigation Systems (CNS) and Electrocardiographic Imaging (ECGI) build detailed three-dimensional electroanatomical maps (EAM), which represent the spatial anatomical distribution of bioelectrical features, such as activation time or voltage. We present a principled methodology for spectral analysis of both EAM geometry and bioelectrical feature in CNS or ECGI, including their spectral representation, cut-off frequency, or spatial sampling rate (SSR)...
June 15, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28635186/catheter-ablation-of-atrial-fibrillation-with-box-isolation-of-fibrotic-areas-lessons-on-fibrosis-distribution-and-extent-clinical-characteristics-and-their-impact-on-long-term-outcome
#2
Doreen Schreiber, Andreas Rieger, Fabian Moser, Hans Kottkamp
INTRODUCTION: The BIFA concept (box isolation of fibrotic areas) supplementing pulmonary vein isolation (PVI) was implemented in atrial fibrillation (AF) patients with fibrotic atrial cardiomyopathy (FACM) to improve catheter ablation outcomes. METHODS AND RESULTS: 92 patients with FACM underwent PVI+BIFA. We investigated patient characteristics (58 persistent/34 paroxysmal,68±8y,LA 44±7mm,CHA2 DS2 -VASc 2.6±1.3,FACM I:15.2%,II:53.3%,III:26.1%,IV:5.4%), periprocedural data concerning fibrosis extent/distribution and their impact on outcome...
June 21, 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/28628123/electrochemical-strain-microscopy-probes-morphology-induced-variations-in-ion-uptake-and-performance-in-organic-electrochemical%C3%A2-transistors
#3
R Giridharagopal, L Q Flagg, J S Harrison, M E Ziffer, J Onorato, C K Luscombe, D S Ginger
Ionic transport phenomena in organic semiconductor materials underpin emerging technologies ranging from bioelectronics to energy storage. The performance of these systems is affected by an interplay of film morphology, ionic transport and electronic transport that is unique to organic semiconductors yet poorly understood. Using in situ electrochemical strain microscopy (ESM), we demonstrate that we can directly probe local variations in ion transport in polymer devices by measuring subnanometre volumetric expansion due to ion uptake following electrochemical oxidation of the semiconductor...
June 19, 2017: Nature Materials
https://www.readbyqxmd.com/read/28615791/monte-carlo-investigation-of-backscatter-point-spread-function-for-x-ray-imaging-examinations
#4
Zhenyu Xiong, Sarath Vijayan, Stephen Rudin, Daniel R Bednarek
X-ray imaging examinations, especially complex interventions, may result in relatively high doses to the patient's skin inducing skin injuries. A method was developed to determine the skin-dose distribution for non-uniform x-ray beams by convolving the backscatter point-spread-function (PSF) with the primary-dose distribution to generate the backscatter distribution that, when added to the primary dose, gives the total-dose distribution. This technique was incorporated in the dose-tracking system (DTS), which provides a real-time color-coded 3D-mapping of skin dose during fluoroscopic procedures...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28607613/complex-fractionated-atrial-electrograms-high-dominant-frequency-regions-and-left-atrial-voltages-during-sinus-rhythm-and-atrial-fibrillation
#5
Naoko Sasaki, Ichiro Watanabe, Yasuo Okumura, Koichi Nagashima, Rikitake Kogawa, Kazumasa Sonoda, Kazuki Iso, Keiko Takahashi, Masaru Arai, Ryuta Watanabe, Sayaka Kurokawa, Kimie Ohkubo, Toshiko Nakai, Atsushi Hirayama, Mizuki Nikaido
BACKGROUND: Ablation targeting complex fractionated atrial electrograms (CFAEs) or high dominant frequency (DF) sites is generally effective for persistent atrial fibrillation (AF). CFAEs and/or high DF sites may exist in low-voltage regions, which theoretically represent abnormal substrates. However, whether CFAEs or high DF sites reflect low voltage substrates during sinus rhythm (SR) is unknown. METHODS: Sixteen patients with AF (8 with paroxysmal AF; 8, persistent AF) underwent high-density mapping of the left atrium (LA) with a 3-dimensional electroanatomic mapping system before ablation...
June 2017: Journal of Arrhythmia
https://www.readbyqxmd.com/read/28605524/prevalence-and-predictors-of-low-voltage-zones-in-the-left-atrium-in-patients-with-atrial-fibrillation
#6
Yan Huo, Thomas Gaspar, Matthias Pohl, Judith Sitzy, Utz Richter, Sebastian Neudeck, Julia Mayer, Mads Brix Kronborg, Christopher Piorkowski
Aims: To describe the extent and distribution of low voltage zones (LVZ) in a large cohort of patients undergoing ablation for paroxysmal and persistent atrial fibrillation (AF), and to explore baseline predictors of LVZ in these patients. Methods and results: Consecutive patients who underwent a bipolar voltage map guided AF ablation, were enrolled. Voltage maps were conducted for each patient using 3-dimensional electroanatomical mapping system and LVZ were defined as areas of bipolar voltage < 0...
June 10, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28603968/ambipolar-mos2-transistors-by-nanoscale-tailoring-of-schottky-barrier-using-oxygen-plasma-functionalization
#7
Filippo Giannazzo, Gabriele Fisichella, Giuseppe Greco, Salvatore Di Franco, Ioannis Deretzis, Antonino La Magna, Corrado Bongiorno, Giuseppe Nicotra, Corrado Spinella, Michelangelo Scopelliti, Bruno Pignataro, Simonpietro Agnello, Fabrizio Roccaforte
One of the main challenges to exploit molybdenum disulfide (MoS2) potentialities for the next generation complementary-metal-oxide-semiconductor (CMOS) technology is the realization of p-type or ambipolar field effect transistors (FETs). Hole transport in MoS2 FETs is typically hampered by the high Schottky barrier height (SBH) for holes at source/drain contacts, due to the Fermi level pinning close to the conduction band. In this work, we show that the SBH of multilayer MoS2 surface can be tailored at nanoscale using soft O2 plasma treatments...
June 12, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28597532/substrate-characterization-and-catheter-ablation-in-patients-with-scar-related-ventricular-tachycardia-using-ultra-high-density-3d-mapping
#8
Jana M Nührich, Lukas Kaiser, Ruken Özge Akbulak, Benjamin N Schäffer, Christian Eickholt, Michael Schwarzl, Pawel Kuklik, Julia Moser, Mario Jularic, Stephan Willems, Christian Meyer
BACKGROUND: Ablation of scar-related ventricular tachycardia (VT), especially in non-inducible VT or hemodynamically unstable patients, can be challenging. Thus, we evaluated feasibility of an ultra high-density 3D-mapping approach to characterize the ventricular substrate and, if possible, to map VT. METHODS AND RESULTS: Twenty-two patients (67±2 years, mean LV-EF 36±3%) with both ischemic and non-ischemic cardiomyopathy and documented VT underwent mapping and catheter ablation using a 64-electrode mini-basket catheter...
June 8, 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/28591591/activation-of-sodium-channel-by-a-novel-%C3%AE-scorpion-toxin-bmk-nt2-stimulates-erk1-2-and-cerb-phosphorylation-through-a-ca-2-dependent-pathway-in-neocortical-neurons
#9
Xiaohan Zou, Ying Wu, Juan Chen, Fang Zhao, Fan Zhang, Boyang Yu, Zhengyu Cao
Neuronal excitability controls the expression of a variety of genes and proteins and therefore regulates neurite outgrowth and synapse formation, fundamental physiological processes controlling learning and memory. Scorpion venom contains many neurotoxins which alter ion channel activities that influence neuronal excitability. In this study, a novel scorpion peptide termed BmK NT2 was purified from venom of Chinese scorpion Buthus martensii Karsch by combining mass spectrum mapping and intracellular Ca(2+) concentration measurement in primary cultured neocortical neurons...
June 4, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28579601/efficacy-of-intensive-radiofrequency-energy-delivery-to-the-localized-dense-scar-area-in-post-infarction-ventricular-tachycardia-ablation%C3%A3-a-comparative-study-with-standard-strategy-targeting-the-infarcted-border-zone
#10
Kenji Kuroki, Akihiko Nogami, Kentaro Yoshida, Masahiko Goya, Masato Fukunaga, Kazuaki Kaitani, Naoaki Onishi, Takanao Mine, Takashi Koyama, Masayuki Igawa, Takeshi Machino, Hiro Yamasaki, Dongzhu Xu, Miyako Igarashi, Nobuyuki Murakoshi, Yukio Sekiguchi, Kazutaka Aonuma
BACKGROUND: Several reports have demonstrated the importance of severely low voltage areas as arrhythmogenic substrates of ventricular tachycardia (VT). However, a comparative study of dense scar-targeted and infarcted border zone-targeted strategies has not been reported.Methods and Results:We divided 109 consecutive patients with VT post-infarction from 6 centers into 2 groups according to the ablation strategy used: dense scar-targeted ablation (DS ablation, 48%) or border zone-targeted ablation (BZ ablation, 52%)...
June 3, 2017: Circulation Journal: Official Journal of the Japanese Circulation Society
https://www.readbyqxmd.com/read/28578165/antihypertensive-and-vasorelaxant-effects-of-aqueous-extract-of-artemisia-campestris-l-from-eastern-morocco
#11
Ikram Dib, Monique Tits, Luc Angenot, Jean Noel Wauters, Asmae Assaidi, Hassane Mekhfi, Mohammed Aziz, Mohammed Bnouham, Abdelkhaleq Legssyer, Michel Frederich, Abderrahim Ziyyat
ETHNOPHARMACOLOGICAL RELEVANCE: Artemisia campestris L. (Asteraceae) has many traditional uses, among which treatment of diabetes and hypertension. AIM OF THE STUDY: This study was conducted in order to confirm the antihypertensive and hypotensive effects of A. campestris L. aqueous extract (AcAE) and to explore the underlying mechanism of action of its vasorelaxant effect, besides the acute toxicity. Also, the chemical composition of AcAE was investigated. MATERIAL AND METHODS: the chemical content of AcAE was determined by using HPLC and NMR techniques...
May 31, 2017: Journal of Ethnopharmacology
https://www.readbyqxmd.com/read/28560240/mesoscale-brain-explorer-a-flexible-python-based-image-analysis-and-visualization-tool
#12
Dirk Haupt, Matthieu P Vanni, Federico Bolanos, Catalin Mitelut, Jeffrey M LeDue, Tim H Murphy
Imaging of mesoscale brain activity is used to map interactions between brain regions. This work has benefited from the pioneering studies of Grinvald et al., who employed optical methods to image brain function by exploiting the properties of intrinsic optical signals and small molecule voltage-sensitive dyes. Mesoscale interareal brain imaging techniques have been advanced by cell targeted and selective recombinant indicators of neuronal activity. Spontaneous resting state activity is often collected during mesoscale imaging to provide the basis for mapping of connectivity relationships using correlation...
July 2017: Neurophotonics
https://www.readbyqxmd.com/read/28558281/optimization-of-sulfate-removal-from-brackish-water-by-membrane-capacitive-deionization-mcdi
#13
Wangwang Tang, Di He, Changyong Zhang, T David Waite
Removal of sulfate from water is an environmental challenge faced by many industrial sectors as most existing options are inefficient, costly or unsustainable. The situation is further complicated by the typical coexistence of other ions. In this work, the feasibility of sulfate removal from brackish water by single-pass constant-current membrane capacitive deionization (MCDI) under reverse-current desorption was investigated. Results revealed that sulfate is preferentially removed from the aqueous solution by MCDI compared to chloride...
May 22, 2017: Water Research
https://www.readbyqxmd.com/read/28546773/successful-bipolar-ablation-for-ventricular-tachycardia-with-potential-substrate-identification-by-pre-procedural-cardiac-magnetic-resonance-imaging
#14
Kazuo Sakamoto, Masatsugu Nozoe, Yoshitomo Tsutsui, Nobuhiro Suematsu, Toru Kubota, Masanori Okabe, Yusuke Yamamoto
Cardiac magnetic resonance imaging (MRI) is a useful tool for detecting the arrhythmogenic substrate in cardiac sarcoidosis. We herein present a case of bipolar radiofrequency catheter ablation for ventricular tachycardia (VT) complicated with cardiac sarcoidosis, guided by pre-procedural cardiac MRI. Neither echocardiography nor endocardial voltage mapping suggested a septal VT substrate. However, MRI alone detected intramural lesions in the septum. Although application of endocardial energy failed to treat the VT, bipolar ablation targeting the potential substrate identified by MRI successfully eliminated the VT...
2017: International Medical Case Reports Journal
https://www.readbyqxmd.com/read/28541417/family-history-of-atrial-fibrillation-as-a-predictor-of-atrial-substrate-and-arrhythmia-recurrence-in-patients-undergoing-atrial-fibrillation-catheter-ablation
#15
Sunil Kapur, Saurabh Kumar, Roy M John, William G Stevenson, Usha B Tedrow, Bruce A Koplan, Laurence M Epstein, Calum A MacRae, Gregory F Michaud
Aims: A commonly held notion is that patients with a family history of atrial fibrillation (AF) have worse atrial substrate and higher rates of arrhythmia recurrence following ablation. We sought to examine differences in atrial substrate and catheter ablation outcomes in patients with a 1st degree family member with paroxysmal or persistent AF (PeAF) compared to those without. Methods and results: A total of 256 consecutive patients undergoing their 1st ablation for AF (123 paroxysmal, 133 persistent) with >1 year follow up were included...
May 24, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28541250/plasmonic-surface-nanostructuring-of-au-dots-sio2-via-laser-irradiation-induced-dewetting
#16
Ruixuan Yu, Tamaki Shibayama, Junya Ishioka, Xuan Meng, Yanhua Lei, Seiichi Watanabe
The in situ observation of Au dot formation and the self-assembly dynamics of Au nanoparticles (NPs) was successfully demonstrated via dewetting of Au thin films on SiO2 glass substrates under nano-second pulsed laser irradiation using a multi-quantum beam high-voltage electron microscope. Moreover, using electron energy-loss spectroscopy (EELS) performed in a scanning transmission electron microscope (STEM), the plasmonic properties of the formed Au/SiO2 nanostructure were analyzed to demonstrate its validity in advanced optical devices...
July 7, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28536891/myocardial-voltage-ratio-in-arrhythmogenic-right-ventricular-dysplasia-cardiomyopathy
#17
REVIEW
Andreas Müssigbrodt, Livio Bertagnolli, Elena Efimova, Jedrzej Kosiuk, Borislav Dinov, Kerstin Bode, Simon Kircher, Nikolaos Dagres, Michael Döring, Sergio Richter, Philipp Sommer, Daniela Husser, Andreas Bollmann, Gerhard Hindricks, Arash Arya
AIMS: This study aimed to analyze the influence of scar distribution between the endocardium and the epicardium in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). METHODS: Electroanatomical mapping data were derived from our ARVD/C registry. Myocardial voltage distribution between the endocardium and the epicardium was analyzed in 28 patients (18 men, 49.9 ± 13.0 years) with previous ventricular tachycardia (VT) ablation and complete right ventricular maps...
May 23, 2017: Herzschrittmachertherapie & Elektrophysiologie
https://www.readbyqxmd.com/read/28507904/electroanatomical-voltage-mapping-of-atrial-mahaim-potentials-to-guide-catheter-ablation
#18
Hiroko Asakai, Laura Fenwick, Robert M Hamilton
No abstract text is available yet for this article.
November 2016: HeartRhythm Case Reports
https://www.readbyqxmd.com/read/28505846/traveling-waves-and-worms-in-ac-driven-electroconvection-under-external-multiplicative-noise
#19
Jong-Hoon Huh
In the presence of external multiplicative noise, ac-driven electroconvection (EC) in a nematic liquid crystal is investigated. Noise-induced traveling waves (TWs) including localized ones (worms) are found with a typical, stationary wave. Three kinds of TWs are classified by their dynamic features (e.g., noise-intensity-dependent Hopf frequency and space-time map). Moreover, ac frequency-dependent threshold voltages of EC are examined in high noise intensities causing abnormal charge redistribution of the EC cell, and the roles of ac and noise fields with respect to TWs are elucidated in successive pattern evolutions...
April 2017: Physical Review. E
https://www.readbyqxmd.com/read/28504937/ultrasonic-fingerprint-sensor-with-transmit-beamforming-based-on-a-pmut-array-bonded-to-cmos-circuitry
#20
Xiaoyue Jiang, Hao-Yen Tang, Yipeng Lu, Eldwin Ng, Julius Tsai, Bernhard Boser, David Horsley
In this paper, we present a single-chip 65x42 element ultrasonic pulse-echo fingerprint sensor with transmit beamforming based on piezoelectric micromachined ultrasonic transducers (PMUTs) directly bonded to a CMOS readout ASIC. The readout ASIC was realized in a standard 180 nm CMOS process with a 24V high voltage transistor option. Pulse-echo measurements are performed column-by-column in sequence using either one column or five columns to transmit the ultrasonic pulse at 20 MHz. Transmit beamforming is used to focus the ultrasonic beam at the imaging plane where the finger is located, increasing the ultrasonic pressure and narrowing the 3dB beam-width to 50 microns, a factor of 6...
May 11, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
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