Read by QxMD icon Read

Voltage Mapping

Kensuke Ihara, Koji Sugiyama, Kentaro Takahashi, Masahiro Yamazoe, Tetsuo Sasano, Tetsushi Furukawa
Recent genome-wide association studies targeting atrial fibrillation (AF) have indicated a strong association between the genotype and electrophysiological phenotype in the atria. That encourages us to utilize a genetically-engineered mouse model to elucidate the mechanism of AF. However, it is difficult to evaluate the electrophysiological properties in murine atria due to their small size. This protocol describes the electrophysiological evaluation of atria using an optical mapping system with a high temporal and spatial resolution in Langendorff perfused murine hearts...
February 22, 2018: Journal of Visualized Experiments: JoVE
Maciej Kubala, Rajeev K Pathak, Shuanglun Xie, Ruben Casado Arroyo, Cory M Tschabrunn, Tatsuya Hayashi, Fermin C Garcia, Gregory E Supple, Pasquale Santangeli, David S Frankel, Erica S Zado, David J Callans, Francis E Marchlinski
BACKGROUND: Repolarization abnormalities in arrhythmogenic right ventricular (RV) cardiomyopathy and their relationship to ventricular tachycardia substrate are incompletely understood. METHODS AND RESULTS: In 40 patients (29 men, mean age 38 years) with arrhythmogenic RV cardiomyopathy, we compared the extent and location of abnormal T (NegT) waves ≥1 mm in depth (n=32) and downsloping elevated ST segment (n=13), in ≥2 adjacent leads, to area and location of endocardial bipolar (<1...
March 2018: Circulation. Arrhythmia and Electrophysiology
Bernd R Gardill, Ricardo E Rivera-Acevedo, Ching-Chieh Tung, Mark Okon, Lawrence P McIntosh, Filip Van Petegem
Voltage-gated sodium channels (NaV ) are responsible for the rapid depolarization of many excitable cells. They readily inactivate, a process where currents diminish after milliseconds of channel opening. They are also targets for a multitude of disease-causing mutations, many of which have been shown to affect inactivation. A cluster of disease mutations, linked to Long-QT and Brugada syndromes, is located in a C-terminal EF-hand like domain of NaV 1.5, the predominant cardiac sodium channel isoform. Previous studies have suggested interactions with the III-IV linker, a cytosolic element directly involved in inactivation...
March 14, 2018: Scientific Reports
Fabian Moser, Andreas Rieger, Christian Pönisch, Hans Kottkamp
INTRODUCTION: Box isolation of fibrotic areas (BIFA) is a promising ablation approach for atrial fibrillation (AF) patients. However, complete isolation of fibrotic anteroseptal left atrial area, where Bachmann's bundle is blending into the left atrial myocardium, is very specific and complex. METHODS AND RESULTS: In 34 AF patients with anteroseptal fibrosis, circumferential BIFA was performed in addition to pulmonary vein isolation. In 8/34 patients, complete isolation of the fibrotic area was achieved with BIFA alone...
March 14, 2018: Journal of Cardiovascular Electrophysiology
Yang Liu, Xiao-Hui Niu, Xiaomeng Yin, Yue-Jian Liu, Chao Han, Jie Yang, Xin Huang, Xiaohong Yu, Lianjun Gao, Yan-Zong Yang, Yun-Long Xia, Hui-Hua Li
BACKGROUND: In atrial fibrillation (AF), a more extensively fibrotic left atrium (LA) provides a substrate for arrhythmias and increases risk of relapse following ablation. Fibrocytes are bone marrow-derived circulating mesenchymal progenitors that have been identified in the atrium of patients with AF who have valvular diseases. The present study investigates the associations between circulating fibrocytes and LA fibrosis or the prevalence of recurrence after ablation in patients with persistent AF...
March 13, 2018: Journal of the American Heart Association
Yoshinari Enomoto, Go Hashimoto, Naohiko Sahara, Hikari Hashimoto, Hiroki Niikura, Keijiro Nakamura, Raisuke Iijima, Hidehiko Hara, Makoto Suzuki, Mahito Noro, Masao Moroi, Kaoru Sugi, Masato Nakamura
A 70-years-old male with a history of hypertension and drug resistant paroxysmal atrial fibrillation (AF) presented to our hospital for catheter ablation to his symptomatic AF. He had no prior surgical or percutaneous procedure to close or exclude the left atrial appendage (LAA). A transesophageal echocardiography (TEE) was performed to rule out intra-cardiac thrombus prior to the ablation procedure. Although the TEE imaging at multiple acquisition angles was obtained, the LAA could not be visualized and an absence of the LAA was suspected...
March 12, 2018: International Heart Journal
Tarek Zghaib, Ali Keramati, Jonathan Chrispin, Dong Huang, Muhammad A Balouch, Luisa Ciuffo, Ronald D Berger, Joseph E Marine, Hiroshi Ashikaga, Hugh Calkins, Saman Nazarian, David D Spragg
Background: Bipolar voltage mapping, as part of atrial fibrillation (AF) ablation, is traditionally performed in a point-by-point (PBP) approach using single-tip ablation catheters. Alternative techniques for fibrosis-delineation include fast-anatomical mapping (FAM) with multi-electrode circular catheters, and late gadolinium-enhanced magnetic-resonance imaging (LGE-MRI). The correlation between PBP, FAM, and LGE-MRI fibrosis assessment is unknown. Objective: In this study, we examined AF substrate using different modalities (PBP, FAM, and LGE-MRI mapping) in patients presenting for an AF ablation...
January 2018: JACC. Clinical Electrophysiology
Vaibhav P Pai, Alexis Pietak, Valerie Willocq, Bin Ye, Nian-Qing Shi, Michael Levin
Endogenous bioelectrical signaling coordinates cell behaviors toward correct anatomical outcomes. Lack of a model explaining spatialized dynamics of bioelectric states has hindered the understanding of the etiology of some birth defects and the development of predictive interventions. Nicotine, a known neuroteratogen, induces serious defects in brain patterning and learning. Our bio-realistic computational model explains nicotine's effects via the disruption of endogenous bioelectrical gradients and predicts that exogenous HCN2 ion channels would restore the endogenous bioelectric prepatterns necessary for brain patterning...
March 8, 2018: Nature Communications
Masaharu Masuda, Masashi Fujita, Osamu Iida, Shin Okamoto, Takayuki Ishihara, Kiyonori Nanto, Takashi Kanda, Takuya Tsujimura, Yasuhiro Matsuda, Shota Okuno, Takuya Ohashi, Aki Tsuji, Toshiaki Mano
BACKGROUND: Association between the presence of left atrial low-voltage areas and atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) has been shown mainly in persistent AF patients. We sought to compare the AF recurrence rate in paroxysmal AF patients with and without left atrial low-voltage areas. METHODS: This prospective observational study included 147 consecutive patients undergoing initial ablation for paroxysmal AF. Voltage mapping was performed after PVI during sinus rhythm, and low-voltage areas were defined as regions where bipolar peak-to-peak voltage was <0...
April 15, 2018: International Journal of Cardiology
Baptiste Maille, Moloy Das, Ahmed Hussein, Matthew Shaw, Vivek Chaturvedi, Maureen Morgan, Christina Ronayne, Richard L Snowdon, Dhiraj Gupta
INTRODUCTION: The ConfiDENSE™ module (Carto3 v4) allows rapid annotation of endocardial electrograms acquired by multi-electrode (ME) mapping. However, its accuracy in assessing atrial voltages is unknown. METHODS AND RESULTS: Two ConfiDENSE™ left atrial voltage maps were created during continuous pacing in 20 patients undergoing catheter ablation for persistent AF using a ME lasso catheter and a Contact Force (CF) sensing ablation catheter. The automated Tissue Proximity indicator (TPI) filter was then applied to the ME map to yield a TPI map...
March 5, 2018: Journal of Cardiovascular Electrophysiology
Laura Martinez-Mateu, Lucia Romero, Ana Ferrer-Albero, Rafael Sebastian, José F Rodríguez Matas, José Jalife, Omer Berenfeld, Javier Saiz
Anatomically based procedures to ablate atrial fibrillation (AF) are often successful in terminating paroxysmal AF. However, the ability to terminate persistent AF remains disappointing. New mechanistic approaches use multiple-electrode basket catheter mapping to localize and target AF drivers in the form of rotors but significant concerns remain about their accuracy. We aimed to evaluate how electrode-endocardium distance, far-field sources and inter-electrode distance affect the accuracy of localizing rotors...
March 5, 2018: PLoS Computational Biology
Shuanglun Xie, Benoit Desjardins, Maciej Kubala, Jackson Liang, Jiandu Yang, Rob J van der Geest, Robert Schaller, Michael Riley, David Callans, Erica Zado Pac, Francis Marchlinski, Saman Nazarian
BACKGROUND: Criteria for identification of anatomic ventricular tachycardia (VT) substrates in arrhythmogenic right ventricular cardiomyopathy (ARVC) on late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) are unclear. OBJECTIVE: We sought to define a) the association of regional RV epicardial voltage amplitude with the distribution of LGE, and b) appropriate image signal intensity (SI) thresholds for VT substrate identification, in ARVC. METHODS: Pre-procedural LGE-CMR and epicardial electrogram mapping were performed in 10 ARVC patients...
March 1, 2018: Heart Rhythm: the Official Journal of the Heart Rhythm Society
Ilya Pozdnyakov, Olga Matantseva, Sergei Skarlato
Four-domain voltage-gated cation channels (FVCCs) represent a large family of pseudo-tetrameric ion channels which includes voltage-gated calcium (Cav ) and sodium (Nav ) channels, as well as their homologues. These transmembrane proteins are involved in a wide range of physiological processes, such as membrane excitability, rhythmical activity, intracellular signalling, etc. Information about actual diversity and phylogenetic relationships of FVCCs across the eukaryotic tree of life is scarce. We for the first time performed a taxonomically broad phylogenetic analysis of 277 FVCC sequences from a variety of eukaryotes and showed that many groups of eukaryotic organisms have their own clades of FVCCs...
February 23, 2018: Scientific Reports
Xiaoming Zhang, Jin-Young Yoon, Michael Morley, Jared M McLendon, Kranti A Mapuskar, Rebecca Gutmann, Haider Mehdi, Heather L Bloom, Samuel C Dudley, Patrick T Ellinor, Alaa A Shalaby, Raul Weiss, W H Wilson Tang, Christine S Moravec, Madhurmeet Singh, Anne L Taylor, Clyde W Yancy, Arthur M Feldman, Dennis M McNamara, Kaikobad Irani, Douglas R Spitz, Patrick Breheny, Kenneth B Margulies, Barry London, Ryan L Boudreau
SCN5A encodes the voltage-gated Na+ channel NaV1.5 that is responsible for depolarization of the cardiac action potential and rapid intercellular conduction. Mutations disrupting the SCN5A coding sequence cause inherited arrhythmias and cardiomyopathy, and single-nucleotide polymorphisms (SNPs) linked to SCN5A splicing, localization, and function associate with heart failure-related sudden cardiac death. However, the clinical relevance of SNPs that modulate SCN5A expression levels remains understudied. We recently generated a transcriptome-wide map of microRNA (miR) binding sites in human heart, evaluated their overlap with common SNPs, and identified a synonymous SNP (rs1805126) adjacent to a miR-24 site within the SCN5A coding sequence...
February 19, 2018: Journal of Clinical Investigation
Mathew J Cherukara, Daniel S Schulman, Kiran Sasikumar, Andrew Joseph Arnold, Henry Chan, Sridhar Sadasivam, Joerg Maser, Wonsuk Cha, Saptarshi Das, Subramanian K R S Sankaranarayanan, Ross J Harder
Emerging 2-D materials such as transition metal dichalcogenides show great promise as viable alternatives for semiconductor and optoelectronic devices that progress beyond silicon. Performance variability, reliability and stochasticity in the measured transport properties represent some of the major challenges in such devices. Native strain arising from interfacial effects due to the presence of a substrate is believed to be a major contributing factor. A full three-dimensional (3-D) mapping of such native nanoscopic strain over micron length scales is highly desirable to gain a fundamental understanding of interfacial effects but has largely remained elusive...
February 16, 2018: Nano Letters
Christopher Piorkowski, Mads Kronborg, Jerome Hourdain, Judith Piorkowski, Bettina Kirstein, Sebastian Neudeck, Simon Wechselberger, Ellen Päßler, Anastasia Löwen, Ali El-Armouche, Julia Mayer, Stefan Ulbrich, Liying Pu, Utz Richter, Thomas Gaspar, Yan Huo
BACKGROUND: Until today, catheter interventional mapping and ablation of atrial fibrillation (AF) has been limited to the right and left atrial endocardium. We report feasibility, electrophysiological findings, and clinical outcome using a combined endo-/epicardial catheter approach for mapping and ablation of AF. METHODS AND RESULTS: Fifty-nine patients with permanence of pulmonary vein isolation and further symptomatic recurrences of paroxysmal AF, persistent AF, or atrial tachycardia underwent reablation using biatrial endo-/epicardial mapping and ablation...
February 2018: Circulation. Arrhythmia and Electrophysiology
Nicholas S Abend, Douglas J Wiebe, Rui Xiao, Shavonne L Massey, Mark Fitzgerald, France Fung, Alexis A Topjian
PURPOSE: We aimed to determine whether conventional standardized EEG features could be consolidated into a more limited number of factors and whether the derived factor scores changed during the acute period after pediatric cardiac arrest. METHODS: Children resuscitated after cardiac arrest underwent conventional continuous EEG monitoring. The EEG was scored in 12-hour epochs for up to 72-hours after return of circulation by an electroencephalographer using standardized critical care EEG terminology...
February 12, 2018: Journal of Clinical Neurophysiology: Official Publication of the American Electroencephalographic Society
Yongxian Xu, Luxin Peng, Sicong Wang, Anqi Wang, Ruirui Ma, Ying Zhou, Jiahe Yang, De-En Sun, Wei Lin, Xing Chen, Peng Zou
Membrane voltage is an important biophysical signal that underlies intercellular electrical communications. In this study, we present a novel fluorescent voltage indicator that enables the investigation of electrical signaling at high spatial resolution. Our method is built upon the site-specific modification of microbial rhodopsin proteins with organic fluorophores, resulting in a hybrid indicator scaffold that represents one of the most sensitive and fastest orange-colored voltage indicators developed to date...
February 13, 2018: Angewandte Chemie
Victor Bazan, Pasquale Santangeli, Francis E Marchlinski
No abstract text is available yet for this article.
February 11, 2018: Pacing and Clinical Electrophysiology: PACE
Ke Pei, Xiaochen Ren, Zhiwen Zhou, Zhichao Zhang, Xudong Ji, Paddy Kwok Leung Chan
Organic optical memory devices keep attracting intensive interests for diverse optoelectronic applications including optical sensors and memories. Here, flexible nonvolatile optical memory devices are developed based on the bis[1]benzothieno[2,3-d;2',3'-d']naphtho[2,3-b;6,7-b']dithiophene (BBTNDT) organic field-effect transistors with charge trapping centers induced by the inhomogeneity (nanosprouts) of the organic thin film. The devices exhibit average mobility as high as 7.7 cm2 V-1 s-1 , photoresponsivity of 433 A W-1 , and long retention time for more than 6 h with a current ratio larger than 106 ...
February 9, 2018: Advanced Materials
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"