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Cardiac electrophysiology

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https://www.readbyqxmd.com/read/29352041/stress-signaling-jnk2-crosstalk-with-camkii-underlies-enhanced-atrial-arrhythmogenesis
#1
Jiajie Yan, Weiwei Zhao, Justin K Thomson, Xianlong Gao, Dominic M DeMarco, Elena Carrillo, Biyi Chen, Xiaomin Wu, Kenneth S Ginsburg, Mamdouh Bakhos, Donald M Bers, Mark E Anderson, Long-Sheng Song, Michael Fill, Xun Ai
Rationale: Atrial fibrillation (AF) is the most common arrhythmia and advanced age is an inevitable and predominant AF risk factor. However, the mechanisms that couple aging and AF propensity remain unclear, making targeted therapeutic interventions unattainable. Objective: To explore the functional role of an important stress-response c-Jun N-terminal kinase (JNK) in sarcoplasmic reticulum (SR) Ca2+ handling and consequently Ca2+-mediated atrial arrhythmias. Methods and Results: We employed a series of cutting-edge electrophysiological and molecular techniques, exploited the power of transgenic mouse models to detail the molecular mechanism, and verified its clinical applicability in parallel studies on donor human hearts...
January 19, 2018: Circulation Research
https://www.readbyqxmd.com/read/29351467/from-ionic-to-cellular-variability-in-human-atrial-myocytes-an-integrative-computational-and-experimental-study
#2
Anna Muszkiewicz, Xing Liu, Alfonso Bueno-Orovio, Brodie A J Lawson, Kevin Burrage, Barbara Casadei, Blanca Rodriguez
Variability refers to differences in physiological function between individuals, which may translate into different disease susceptibility and treatment efficacy. Experiments in human cardiomyocytes face wide variability and restricted tissue access; under these conditions computational models are a useful complementary tool. We conducted a computational and experimental investigation in cardiomyocytes isolated from samples of the right atrial appendage of patients undergoing cardiac surgery to evaluate the impact of variability in action potentials (APs) and sub-cellular ionic densities on calcium transient dynamics...
December 22, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29349296/unlocking-data-sets-by-calibrating-populations-of-models-to-data-density-a-study-in-atrial-electrophysiology
#3
Brodie A J Lawson, Christopher C Drovandi, Nicole Cusimano, Pamela Burrage, Blanca Rodriguez, Kevin Burrage
The understanding of complex physical or biological systems nearly always requires a characterization of the variability that underpins these processes. In addition, the data used to calibrate these models may also often exhibit considerable variability. A recent approach to deal with these issues has been to calibrate populations of models (POMs), multiple copies of a single mathematical model but with different parameter values, in response to experimental data. To date, this calibration has been largely limited to selecting models that produce outputs that fall within the ranges of the data set, ignoring any trends that might be present in the data...
January 2018: Science Advances
https://www.readbyqxmd.com/read/29348631/dynamic-all-optical-drug-screening-on-cardiac-voltage-gated-ion-channels
#4
Jonas Streit, Sonja Kleinlogel
Voltage-gated ion channels (VGCs) are prime targets for the pharmaceutical industry, but drug profiling on VGCs is challenging, since drug interactions are confined to specific conformational channel states mediated by changes in transmembrane potential. Here we combined various optogenetic tools to develop dynamic, high-throughput drug profiling assays with defined light-step protocols to interrogate VGC states on a millisecond timescale. We show that such light-induced electrophysiology (LiEp) yields high-quality pharmacological data with exceptional screening windows for drugs acting on the major cardiac VGCs, including hNav1...
January 18, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29347921/prospective-pre-and-post-race-evaluation-of-biochemical-electrophysiologic-and-echocardiographic-indices-in-30-racing-thoroughbred-horses-that-received-furosemide
#5
Catherine T Gunther-Harrington, Rick Arthur, Krista Estell, Beatriz Martinez Lopez, Alexandra Sinnott, Eric Ontiveros, Anita Varga, Joshua A Stern
BACKGROUND: Exercise induced cardiac fatigue (EICF) and cardiac dysrhythmias are well described conditions identified in high-level human athletes that increase in frequency with intensity and duration of exercise. Identification of these conditions requires an understanding of normal pre- and post-race cardiac assessment values. The objectives of this study were to (1) characterize selected indices of cardiac function, electrophysiologic parameters, and biochemical markers of heart dysfunction prior to and immediately after high level racing in Thoroughbred horses receiving furosemide; and (2) create pre- and post-race reference values in order to make recommendations on possible screening practices for this population in the future...
January 18, 2018: BMC Veterinary Research
https://www.readbyqxmd.com/read/29342363/differential-effects-of-inhibitory-g-protein-isoforms-on-g-protein-gated-inwardly-rectifying-k-currents-in-adult-murine-atria
#6
Muriel Nobles, David Montaigne, Sonia Sebastian, Lutz Birnbaumer, Andrew Tinker
G-protein gated inwardly rectifying K+ (GIRK) channels are the major inwardly rectifying K+ currents in cardiac atrial myocytes and an important determinant of atrial electrophysiology. Inhibitory G-protein alpha subunits can both mediate activation via acetylcholine but can also supress basal currents in the absence of agonist. We studied this phenomenon using whole cell patch clamping in murine atria from mice with global genetic deletion of Gαi2, combined deletion of Gαi1/Gαi3 and littermate controls...
January 17, 2018: American Journal of Physiology. Cell Physiology
https://www.readbyqxmd.com/read/29342222/mechano-electric-feedback-effects-in-a-three-dimensional-3d-model-of-the-contracting-cardiac-ventricle
#7
Ani Amar, Sharon Zlochiver, Ofer Barnea
Mechano-electric feedback affects the electrophysiological and mechanical function of the heart and the cellular, tissue, and organ properties. To determine the main factors that contribute to this effect, this study investigated the changes in the action potential characteristics of the ventricle during contraction. A model of stretch-activated channels was incorporated into a three-dimensional multiscale model of the contracting ventricle to assess the effect of different preload lengths on the electrophysiological behavior...
2018: PloS One
https://www.readbyqxmd.com/read/29338549/sedation-in-cardiac-arrhythmias-management
#8
Federico Guerra, Giulia Stronati, Alessandro Capucci
Procedural sedation is of paramount importance for a plethora of electrophysiological procedures. From electrical cardioversion to electrophysiology studies, device implantations, and catheter ablations, intraprocedural sedation and anesthesia have a pivotal role in allowing procedural success while ensuring patient safety and avoiding discomfort. Areas covered: The present review will discuss the current state-of-the-art in sedation and anesthesia during electrical cardioversion, cardiac implantable electronic device implantation, catheter ablation and electrophysiology studies...
January 17, 2018: Expert Review of Cardiovascular Therapy
https://www.readbyqxmd.com/read/29336212/simulated-microgravity-impairs-cardiac-autonomic-neurogenesis-from-neural-crest-cells
#9
Konstantinos E Hatzistergos, Zhijie Jiang, Krystalenia Valasaki, Lauro M Takeuchi, Wayne Balkan, Preethi Atluri, Dieter Saur, Barbara Seidler, Nicholas Tsinoremas, Darcy DiFede, Joshua M Hare
Microgravity-induced alterations in the autonomic nervous system (ANS) contribute to derangements in both the mechanical and electrophysiologic function of the cardiovascular system, leading to severe symptoms in humans following space travel. Because the ANS forms embryonically from neural crest progenitors (NCs), we hypothesized that microgravity can impair NC derived cardiac structures. Accordingly, we conducted in vitro simulated microgravity experiments employing NC genetic lineage-tracing in mice with cKitCreERT2/+, Isl1nLacZ and Wnt1-Cre reporter alleles...
January 16, 2018: Stem Cells and Development
https://www.readbyqxmd.com/read/29332573/torsades-de-pointes-in-patients-with-polymyalgia-rheumatica
#10
Pietro Enea Lazzerini, Iacopo Bertolozzi, Maurizio Acampa, Rosella Fulceri, Franco Laghi-Pasini, Pier Leopoldo Capecchi
Polymyalgia rheumatica (PMR) represents the most common inflammatory rheumatic disease of the elderly. It is characterized by synovitis of proximal joints and extra-articular synovial structures, along with chronic high-grade systemic inflammation. PMR is closely related to giant cell arteritis (GCA), a large-vessel vasculitis that involves the major branches of the aorta, particularly the extracranial branches of carotid artery including temporal arteries. It is currently believed that PMR and GCA may represent different manifestations of the same disease process...
January 10, 2018: Current Pharmaceutical Design
https://www.readbyqxmd.com/read/29327314/computational-modeling-for-cardiac-resynchronization-therapy
#11
Angela W C Lee, Caroline Mendonca Costa, Marina Strocchi, Christopher A Rinaldi, Steven A Niederer
Cardiac resynchronization therapy (CRT) is an effective treatment for heart failure (HF) patients with an electrical substrate pathology causing ventricular dyssynchrony. However 40-50% of patients do not respond to treatment. Cardiac modeling of the electrophysiology, electromechanics, and hemodynamics of the heart has been used to study mechanisms behind HF pathology and CRT response. Recently, multi-scale dyssynchronous HF models have been used to study optimal device settings and optimal lead locations, investigate the underlying cardiac pathophysiology, as well as investigate emerging technologies proposed to treat cardiac dyssynchrony...
January 11, 2018: Journal of Cardiovascular Translational Research
https://www.readbyqxmd.com/read/29326130/inward-rectifier-potassium-channels-kir2-x-and-caveolin-3-domain-specific-interaction-implications-for-purkinje-cell-dependent-ventricular-arrhythmias
#12
Ravi Vaidyanathan, Hanora Van Ert, Kazi T Haq, Stefano Morotti, Samuel Esch, Elise C McCune, Eleonora Grandi, Lee L Eckhardt
BACKGROUND: In human cardiac ventricle, IK1 is mainly comprised Kir2.1, but Kir2.2 and Kir2.3 heterotetramers occur and modulate IK1. Long-QT syndrome-9-associated CAV3 mutations cause decreased Kir2.1 current density, but Kir2.x heterotetramers have not been studied. Here, we determine the effect of long-QT syndrome-9-CAV3 mutation F97C on Kir2.x homo- and heterotetramers and model-associated arrhythmia mechanisms. METHODS AND RESULTS: Super-resolution microscopy, co-immunoprecipitation, cellular electrophysiology, on-cell Western blotting, and simulation of Purkinje and ventricular myocyte mathematical models were used...
January 2018: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/29325976/profile-of-brugada-syndrome-patients-presenting-with-their-first-documented-arrhythmic-event-data-from-the-survey-on-arrhythmic-events-in-brugada-syndrome-sabrus
#13
Anat Milman, Antoine Andorin, Jean-Baptiste Gourraud, Pieter G Postema, Frederic Sacher, Philippe Mabo, Sung-Hwan Kim, Jimmy Jm Juang, Shingo Maeda, Yoshihide Takahashi, Tsukasa Kamakura, Takeshi Aiba, Giulio Conte, Georgia Sarquella-Brugada, Eran Leshem, Michael Rahkovich, Aviram Hochstadt, Yuka Mizusawa, Elena Arbelo, Zhengrong Huang, Isabelle Denjoy, Carla Giustetto, Yanushi D Wijeyeratne, Carlo Napolitano, Yoav Michowitz, Ramon Brugada, Ruben Casado-Arroyo, Jean Champagne, Leonardo Calo, Jacob Tfelt-Hansen, Silvia G Priori, Masahiko Takagi, Christian Veltmann, Pietro Delise, Domenico Corrado, Elijah R Behr, Fiorenzo Gaita, Gan-Xin Yan, Josep Brugada, Antoine Leenhardt, Arthur A M Wilde, Pedro Brugada, Kengo F Kusano, Kenzo Hirao, Gi-Byoung Nam, Vincent Probst, Bernard Belhassen
BACKGROUND: Detailed information on the profile of Brugada syndrome (BrS) patients presenting their first arrhythmic event (AE) after prophylactic implantation of a cardioverter defibrillator (ICD) is limited. OBJECTIVES: 1) To compare clinical, electrocardiographic, electrophysiologic and genetic profiles of patients who exhibited their first documented AE as aborted cardiac arrest (CA) (group A) with those in whom the AE was documented after prophylactic ICD implantation (group B); 2) To characterize group B patients' profile using the Class II indications for ICD implantation established by HRS/EHRA/APHRS Expert Consensus Statement in 2013...
January 8, 2018: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/29325842/use-of-dexmedetomidine-in-cardiothoracic-and-vascular-anesthesia
#14
REVIEW
Lucía Gallego-Ligorit, Marc Vives, Jorge Vallés-Torres, T Alberto Sanjuán-Villarreal, Azucena Pajares, Mario Iglesias
Dexmedetomidine is a highly selective α2-adrenergic agonist with analgesic and sedative properties. In the United States, the Food and Drug Administration approved the use of the drug for short-lasting sedation (24 h) in intensive care units (ICUs) in patients undergoing mechanical ventilation and endotracheal intubation. In October 2008, the Food and Drug Administration extended use of the drug for the sedation of nonintubated patients before and during surgical and nonsurgical procedures. In the European Union, the European Medicine Agency approved the use of dexmedetomidine in September 2011 with a single recognized indication: ICU adult patients requiring mild sedation and awakening in response to verbal stimulus...
December 2, 2017: Journal of Cardiothoracic and Vascular Anesthesia
https://www.readbyqxmd.com/read/29324898/the-etomidate-analog-et-26-hcl-retains-superior-myocardial-performance-comparisons-with-etomidate-in-vivo-and-in-vitro
#15
Xingxing Liu, Haibo Song, Jun Yang, Cheng Zhou, Yi Kang, Linghui Yang, Jin Liu, Wensheng Zhang
OBJECTIVE: (R)-2-methoxyethyl1-(1-phenylethyl)-1H-imidazole-5-carboxylate hydrochloride (ET-26 HCl) is a novel etomidate analogue. The purpose of this study was to characterize whether ET-26 HCl could retain the superior myocardial performance of etomidate in vivo and in vitro. METHODS: In vivo, the influence of ET-26 HCl and etomidate on the cardiac function of dogs was confirmed using echocardiography and electrocardiogram. In vitro, a Langendorff preparation was used to examine direct myocardial performance in isolated rat hearts, and a whole-cell patch-clamp technique was used to study effects on the human ether-a-go-go-related gene (hERG) channel...
2018: PloS One
https://www.readbyqxmd.com/read/29319404/gender-differences-in-utilization-of-specialized-heart-failure-clinics
#16
Lusine Abrahamyan, Yeva Sahakyan, Harindra C Wijeysundera, Murray Krahn, Valeria E Rac
BACKGROUND: Although heart failure (HF) prevalence is equally high among men and women, observed differences in the provision of care are still not fully understood. We sought to evaluate gender differences in patient profiles, diagnostic testing, medication prescription, and referrals in specialized multidisciplinary ambulatory HF clinics in Ontario. MATERIALS AND METHODS: Medical chart abstraction was conducted first by randomly selecting 9 (out of 34) HF clinics in Ontario, and then by randomly selecting 100 patient records in each clinic...
January 10, 2018: Journal of Women's Health
https://www.readbyqxmd.com/read/29316340/an-adaptive-hybridizable-discontinuous-galerkin-approach-for-cardiac-electrophysiology
#17
J M Hoermann, C Bertoglio, M Kronbichler, M R Pfaller, R Chabiniok, W A Wall
Cardiac electrophysiology simulations are numerically challenging due to the propagation of a steep electrochemical wave front and thus require discretizations with small mesh sizes to obtain accurate results. In this work, we present an approach based on the Hybridizable Discontinuous Galerkin method (HDG), which allows an efficient implementation of high-order discretizations into a computational framework. In particular using the advantage of the discontinuous function space, we present an efficient p-adaptive strategy for accurately tracking the wave front...
January 8, 2018: International Journal for Numerical Methods in Biomedical Engineering
https://www.readbyqxmd.com/read/29315402/cardiac-optogenetics-the-next-frontier
#18
Amit Gruber, Oded Edri, Lior Gepstein
The emerging technology of optogenetics uses optical and genetic means to monitor and modulate the electrophysiological properties of excitable tissues. While transforming the field of neuroscience, the technology has recently gained popularity also in the cardiac arena. Here, we describe the basic principles of optogenetics, the available and evolving optogenetic tools, and the unique potential of this technology for basic and translational cardiac electrophysiology. Specifically, we discuss the ability to control (augment or suppress) the cardiac tissue's excitable properties using optogenetic actuators (microbial opsins), which are light-gated ion channels and pumps that can cause light-triggered membrane depolarization or hyperpolarization...
January 5, 2018: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/29313139/report-on-the-ion-channel-symposium-organized-by-the-german-cardiac-society-working-group-on-cellular-electrophysiology-ag%C3%A2-18
#19
REVIEW
Niels Voigt, Fleur Mason, Dierk Thomas
To support scientific exchange and activity in the field of cardiac cellular electrophysiology, the German Cardiac Society Working Group on Cellular Electrophysiology (AG 18) established a two-day symposium to be held every 2 years. The second Ion Channel Symposium entitled "Göttingen Channels 2017-Of Benches and Beds" took place in Göttingen from September 22nd to 23rd under the auspices of the German Cardiac Society. A group of national and international experts presented scientific advances in cardiac electrophysiology and rhythmology...
January 8, 2018: Herzschrittmachertherapie & Elektrophysiologie
https://www.readbyqxmd.com/read/29312750/mitral-valve-prolapse-an-underestimated-cause-of-sudden-cardiac-death-a-current-review-of-the-literature
#20
REVIEW
Michael Spartalis, Eleni Tzatzaki, Eleftherios Spartalis, Antonios Athanasiou, Demetrios Moris, Christos Damaskos, Nikolaos Garmpis, Vassilis Voudris
Mitral valve prolapse (MVP) is a common valve abnormality in general population. Despite the general belief of a benign disorder, several articles since the 1980s report sudden cardiac death (SCD) in MVP patients, with a substantial percentage of asymptomatic young individuals. The problem is to detect those patients at increased risk and implement methods that are suitable to prevent cardiac arrest. This review investigates the correlation between MVP and SCD, the understanding of the pathophysiology, the strategies for detecting those at risk and treatment options...
December 2017: Journal of Thoracic Disease
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