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Cardiac electrophysiology

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https://www.readbyqxmd.com/read/28646025/remodeling-of-repolarization-and-arrhythmia-susceptibility-in-a-myosin-binding-protein-c-knockout-mouse-model
#1
Amir Toib, Chen Zhang, Giulia Borghetti, Xiaoxiao Zhang, Markus Wallner, Yijun Yang, Constantine Troupes, Hajime Kubo, Thomas Sharp, Eric Feldsott, Remus M Berretta, Neil Zalavadia, Danielle Trappanese, Shavonn Harper, Polina Gross, Xiongwen Chen, Sadia Mohsin, Steven Houser
Hypertrophic cardiomyopathy (HCM) is one of the most common genetic cardiac diseases and amongst the leading causes of sudden cardiac death (SCD) in the young. The cellular mechanisms leading to SCD in HCM are not well known. Prolongation of the action potential duration (APD) is a common feature predisposing hypertrophied hearts to SCD. Previous studies have explored the roles of inward Na(+) and Ca(2+) in the development of HCM, but the role of repolarizing K(+) currents have not been defined. The objective of this study was to characterize the arrhythmogenic phenotype and cellular electrophysiological properties of mice with HCM, induced by Myosin Binding Protein C (MyBPC) Knockout (KO) and to test the hypothesis that remodeling of repolarizing K(+) currents cause APD prolongation in MyBPC KO myocytes...
June 23, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28645806/brugada-syndrome-a-general-cardiologist-s-perspective
#2
REVIEW
Marija M Polovina, Milica Vukicevic, Bojan Banko, Gregory Y H Lip, Tatjana S Potpara
Brugada syndrome (BrS) is one of the commonest inherited primary arrhythmia syndromes typically presenting with arrhythmic syncope or sudden cardiac death (SCD) due to polymorphic ventricular tachycardia and ventricular fibrillation precipitated by vagotonia or fever in apparently healthy adults, less frequently in children. The prevalence of the syndrome (0.01%-0.3%) varies among regions and ethnicities, being the highest in Southeast Asia. BrS is diagnosed by the "coved type" ST-segment elevation≥2mm followed by a negative T-wave in ≥1 of the right precordial leads V1-V2...
June 20, 2017: European Journal of Internal Medicine
https://www.readbyqxmd.com/read/28644868/electrophysiological-alterations-in-a-murine-model-of-chronic-coxsackievirus-b3-myocarditis
#3
Sven Kaese, Robert Larbig, Matthias Rohrbeck, Gerrit Frommeyer, Dirk Dechering, Jan Olligs, Sabine Schönhofer-Merl, Rainer Wessely, Karin Klingel, Guiscard Seebohm, Lars Eckardt
INTRODUCTION: Coxsackievirus B3 (CVB3) is known to induce acute and chronic myocarditis. Most infections are clinically unapparent but some patients suffer from ventricular arrhythmias (VA) and sudden cardiac death (SCD). Studies showed that acute CVB3 infection may cause impaired function of cardiac ion channels, creating a proarrhythmic substrate. However, it is unknown whether low level CVB3+ expression in myocytes may cause altered cardiac electrophysiology leading to VA. METHODS: Cellular electrophysiology was used to analyze cellular action potentials (APs) and occurrence of afterdepolarizations from isolated cardiomyocytes of wildtype (WT) and transgenic CVB3ΔVP0 (CVB3+) mice...
2017: PloS One
https://www.readbyqxmd.com/read/28643175/-clinical-aspects-of-treatment-with-amiodarone
#4
REVIEW
W Haverkamp, C Israel, A Parwani
Amiodarone has multiple and complex electrophysiological effects that render it a very effective antiarrhythmic drug for the treatment of both, supraventricular and ventricular arrhythmias. Proarrhythmic effects of amiodarone in patients with structural heart disease are rare. However, extracardiac adverse effects occurring in association with amiodarone treatment are frequent and feared. These adverse effects have usually been related to total amiodarone exposure (i. e., dose and duration of treatment)...
June 22, 2017: Herzschrittmachertherapie & Elektrophysiologie
https://www.readbyqxmd.com/read/28641381/supraventricular-tachyarrhythmias-in-patients-with-a-persistent-left-superior-vena-cava
#5
Jongmin Hwang, Hyoung-Seob Park, Jun Kim, Jeong Su Kim, Jong Sung Park, Ki-Hun Kim, Myung Hwan Bae, Sang-Hee Lee, Young Soo Lee, Seongwook Han, Dae-Kyeong Kim, Tae-Joon Cha, Dong Gu Shin, Byung Chun Jung, Yoon-Nyun Kim
Aims: A persistent left superior vena cava (PLSVC) is the most common thoracic venous anomaly. This venous anomaly can impact the evaluation and treatment of supraventricular tachyarrhythmia (SVA). The aim of this study was to assess the proportion and characteristics of PLSVC in adult SVA patients. Methods and results: From July 2002 to July 2012, clinical and procedural data from databases of 10 cardiac electrophysiology laboratories in the Yeungnam region of the Republic of Korea were reviewed...
June 20, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28641242/arrhythmia-mechanism-and-scaling-effect-on-the-spectral-properties-of-electroanatomical-maps-with-manifold-harmonics
#6
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/28640451/cardiac-fibrosis-and-arrhythmogenesis
#7
My-Nhan Nguyen, Helen Kiriazis, Xiao-Ming Gao, Xiao-Jun Du
Myocardial injury, mechanical stress, neurohormonal activation, inflammation, and/or aging all lead to cardiac remodeling, which is responsible for cardiac dysfunction and arrhythmogenesis. Of the key histological components of cardiac remodeling, fibrosis either in the form of interstitial, patchy, or dense scars, constitutes a key histological substrate of arrhythmias. Here we discuss current research findings focusing on the role of fibrosis, in arrhythmogenesis. Numerous studies have convincingly shown that patchy or interstitial fibrosis interferes with myocardial electrophysiology by slowing down action potential propagation, initiating reentry, promoting after-depolarizations, and increasing ectopic automaticity...
June 18, 2017: Comprehensive Physiology
https://www.readbyqxmd.com/read/28639003/the-crucial-role-of-activin-a-alk4-pathway-in-the-pathogenesis-of-ang-ii-induced-atrial-fibrosis-and-vulnerability-to-atrial-fibrillation
#8
Qian Wang, Ying Yu, Pengpai Zhang, Yihe Chen, Changyi Li, Jie Chen, Yuepeng Wang, Yigang Li
Atrial fibrosis, the hallmark of structural remodeling associated with atrial fibrillation (AF), is characterized by abnormal proliferation of atrial fibroblasts and excessive deposition of extracellular matrix. Transforming growth factor-β1 (TGF-β1)/activin receptor-like kinase 5 (ALK5)/Smad2/3/4 pathway has been reported to be involved in the process. Recent studies have implicated both activin A and its specific downstream component activin receptor-like kinase 4 (ALK4) in stimulating fibrosis in non-cardiac organs...
July 2017: Basic Research in Cardiology
https://www.readbyqxmd.com/read/28638576/a-classic-case-of-arrhythmogenic-right-ventricular-cardiomyopathy-arvc-and-literature-review
#9
Htun Latt, Thein Tun Aung, Chanwit Roongsritong, David Smith
Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is a relatively under-recognized hereditary cardiomyopathy. It is characterized pathologically by fibro-fatty infiltration of right ventricular (RV) myocardium and clinically by consequences of RV electrical instability. Timely intervention with device therapy and pharmacotherapy may help reduce the risk of arrhythmic events or sudden cardiac death. Here, we describe a classic case of a young adult with ARVC and a brief literature review. The patient presented with exertional palpitations and ARVC was suspected after his routine electrocardiogram (EKG) revealed symmetric T wave inversions and possible epsilon waves in right precordial leads...
March 2017: Journal of Community Hospital Internal Medicine Perspectives
https://www.readbyqxmd.com/read/28637969/development-of-a-patient-derived-induced-pluripotent-stem-cell-model-for-the-investigation-of-scn5a-d1275n-related-cardiac-sodium-channelopathy
#10
Mamoru Hayano, Takeru Makiyama, Tsukasa Kamakura, Hiroshi Watanabe, Kenichi Sasaki, Shunsuke Funakoshi, Yimin Wuriyanghai, Suguru Nishiuchi, Takeshi Harita, Yuta Yamamoto, Hirohiko Kohjitani, Sayako Hirose, Fumika Yokoi, Jiarong Chen, Osamu Baba, Takahiro Horie, Kazuhisa Chonabayashi, Seiko Ohno, Futoshi Toyoda, Yoshinori Yoshida, Koh Ono, Minoru Horie, Takeshi Kimura
BACKGROUND: TheSCN5Agene encodes the α subunit of the cardiac voltage-gated sodium channel, NaV1.5. The missense mutation, D1275N, has been associated with a range of unusual phenotypes associated with reduced NaV1.5 function, including cardiac conduction disease and dilated cardiomyopathy. Curiously, the reported biophysical properties ofSCN5A-D1275N channels vary with experimental system.Methods and Results:First, using a human embryonic kidney (HEK) 293 cell-based heterologous expression system, theSCN5A-D1275N channels showed similar maximum sodium conductance but a significantly depolarizing shift of activation gate (+10 mV) compared to wild type...
June 20, 2017: Circulation Journal: Official Journal of the Japanese Circulation Society
https://www.readbyqxmd.com/read/28637782/the-brugada-syndrome-susceptibility-gene-hey2-modulates-cardiac-transmural-ion-channel-patterning-and-electrical-heterogeneity
#11
Christiaan C Veerman, Svitlana Podliesna, Rafik Tadros, Elisabeth M Lodder, Isabella Mengarelli, Berend de Jonge, Leander Beekman, Julien Barc, Ronald Wilders, Arthur A Wilde, Bastiaan J Boukens, Ruben Coronel, Arie Verkerk, Carol Ann Remme, Connie R Bezzina
Rationale: Genome-wide association studies previously identified an association of rs9388451 at chromosome 6q22.3 (near HEY2) with Brugada syndrome (BrS). The causal gene and underlying mechanism remain unresolved. Objective: We used an integrative approach entailing transcriptomic studies in human hearts and electrophysiological studies in Hey2 heterozygous knockout mice (Hey2(+/-) ) to dissect the underpinnings of the 6q22.31 association with BrS. Methods and Results: We queried expression quantitative trait locus (eQTL) data acquired in 190 human left ventricular (LV) samples from the Genotype-Tissue Expression (GTEx) consortium for cis-eQTL effects of rs9388451 which revealed an association between BrS risk allele dosage and HEY2 expression (β=+0...
June 21, 2017: Circulation Research
https://www.readbyqxmd.com/read/28636811/performance-evaluation-of-gpu-parallelization-space-time-adaptive-algorithms-and-their-combination-for-simulating-cardiac-electrophysiology
#12
Rafael S Oliveira, Bernardo M Rocha, Denise Burgarelli, Wagner Meira, Christakis Constantinides, Rodrigo Weber Dos Santos
The use of computer models as a tool for the study and understanding of the complex phenomena of cardiac electrophysiology has attained increased importance nowadays. At the same time, the increased complexity of the biophysical processes translates into complex computational and mathematical models. In order to speed up cardiac simulations and to allow more precise and realistic uses, two different techniques have been traditionally exploited: parallel computing and sophisticated numerical methods. In this work, we combine a modern parallel computing technique based on multicore and graphics processing units (GPUs), and a sophisticated numerical method based on a new space-time adaptive algorithm...
June 21, 2017: International Journal for Numerical Methods in Biomedical Engineering
https://www.readbyqxmd.com/read/28635246/patient-specific-cardiac-electrophysiology
#13
Riccardo Proietti
No abstract text is available yet for this article.
August 2017: Minerva Cardioangiologica
https://www.readbyqxmd.com/read/28634147/csahi-study-2-validation-of-multi-electrode-array-systems-mea60-2100-for-prediction-of-drug-induced-proarrhythmia-using-human-ips-cell-derived-cardiomyocytes-assessment-of-reference-compounds-and-comparison-with-non-clinical-studies-and-clinical-information
#14
Yumiko Nozaki, Yayoi Honda, Hitoshi Watanabe, Shota Saiki, Kiyotaka Koyabu, Tetsuji Itoh, Chiho Nagasawa, Chiaki Nakamori, Chiaki Nakayama, Hiroshi Iwasaki, Shinobu Suzuki, Kohji Tanaka, Etsushi Takahashi, Kaori Miyamoto, Kaoru Morimura, Atsuhiro Yamanishi, Hiroko Endo, Junko Shinozaki, Hisashi Nogawa, Tadahiro Shinozawa, Fumiyo Saito, Takeshi Kunimatsu
With the aim of reconsidering ICH S7B and E14 guidelines, a new in vitro assay system has been subjected to worldwide validation to establish a better prediction platform for potential drug-induced QT prolongation and the consequent TdP in clinical practice. In Japan, CSAHi HEART team has been working on hiPS-CMs in the MEA (hiPS-CMs/MEA) under a standardized protocol and found no inter-facility or lot-to-lot variability for proarrhythmic risk assessment of 7 reference compounds. In this study, we evaluated the responses of hiPS-CMs/MEA to another 31 reference compounds associated with cardiac toxicities, and gene expression to further clarify the electrophysiological characteristics over the course of culture period...
June 17, 2017: Regulatory Toxicology and Pharmacology: RTP
https://www.readbyqxmd.com/read/28630564/cathrob-a-highly-compact-and-versatile-remote-catheter-navigation-system
#15
Laura Cercenelli, Barbara Bortolani, Emanuela Marcelli
Several remote catheter navigation systems have been developed and are now commercially available. However, these systems typically require specialized catheters or equipment, as well as time-consuming operations for the system set-up. In this paper, we present CathROB, a highly compact and versatile robotic system for remote navigation of standard tip-steerable electrophysiology (EP) catheters. Key features of CathROB include an extremely compact design that minimizes encumbrance and time for system set-up in a standard cath lab, a force-sensing mechanism, an intuitive command interface, and functions for automatic catheter navigation and repositioning...
2017: Applied Bionics and Biomechanics
https://www.readbyqxmd.com/read/28623610/a-singular-role-of-ik1-promoting-the-development-of-cardiac-automaticity-during-cardiomyocyte-differentiation-by-ik1-induced-activation-of-pacemaker-current
#16
Yu Sun, Valeriy Timofeyev, Adrienne Dennis, Emre Bektik, Xiaoping Wan, Kenneth R Laurita, Isabelle Deschênes, Ronald A Li, Ji-Dong Fu
The inward rectifier potassium current (IK1) is generally thought to suppress cardiac automaticity by hyperpolarizing membrane potential (MP). We recently observed that IK1 could promote the spontaneously-firing automaticity induced by upregulation of pacemaker funny current (If) in adult ventricular cardiomyocytes (CMs). However, the intriguing ability of IK1 to activate If and thereby promote automaticity has not been explored. In this study, we combined mathematical and experimental assays and found that only IK1 and If, at a proper-ratio of densities, were sufficient to generate rhythmic MP-oscillations even in unexcitable cells (i...
June 16, 2017: Stem Cell Reviews
https://www.readbyqxmd.com/read/28621620/deep-brain-stimulation-for-the-early-treatment-of-the-minimally-conscious-state-and-vegetative-state-experience-in-14-patients
#17
Darko Chudy, Vedran Deletis, Fadi Almahariq, Petar Marčinković, Jasenka Škrlin, Veronika Paradžik
OBJECTIVE An effective treatment of patients in a minimally conscious state (MCS) or vegetative state (VS) caused by hypoxic encephalopathy or traumatic brain injury (TBI) is not yet available. Deep brain stimulation (DBS) of the thalamic reticular nuclei has been attempted as a therapeutic procedure mainly in patients with TBI. The purpose of this study was to investigate the therapeutic use of DBS for patients in VS or MCS. METHODS Fourteen of 49 patients in VS or MCS qualified for inclusion in this study and underwent DBS...
June 16, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/28620319/vascular-endothelial-growth-factor-b-induces-a-distinct-electrophysiological-phenotype-in-mouse-heart
#18
Nikolay Naumenko, Jenni Huusko, Tomi Tuomainen, Jussi T Koivumäki, Mari Merentie, Erika Gurzeler, Kari Alitalo, Riikka Kivelä, Seppo Ylä-Herttuala, Pasi Tavi
Vascular endothelial growth factor B (VEGF-B) is a potent mediator of vascular, metabolic, growth, and stress responses in the heart, but the effects on cardiac muscle and cardiomyocyte function are not known. The purpose of this study was to assess the effects of VEGF-B on the energy metabolism, contractile, and electrophysiological properties of mouse cardiac muscle and cardiac muscle cells. In vivo and ex vivo analysis of cardiac-specific VEGF-B TG mice indicated that the contractile function of the TG hearts was normal...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28613240/an-isoform-of-nedd4-2-plays-a-pivotal-role-in-electrophysiological-cardiac-abnormalities
#19
Shintaro Minegishi, Tomoaki Ishigami, Hisho Kawamura, Tabito Kino, Lin Chen, Rie Nakashima-Sasaki, Hiroshi Doi, Kengo Azushima, Hiromichi Wakui, Yumi Chiba, Kouichi Tamura
We have previously shown that neural precursor cell-expressed developmentally downregulated gene 4-2 (Nedd4-2) isoforms with a C2 domain are closely related to ubiquitination of epithelial sodium channel (ENaC), resulting in salt-sensitive hypertension by Nedd4-2 C2 targeting in mice. The sodium voltage-gated channel alpha subunit 5 (SCN5A) gene encodes the α subunit of the human cardiac voltage-gated sodium channel (I Na), and the potassium voltage-gated channel subfamily H member 2 (KCNH2) gene encodes rapidly activating delayed rectifier K channels (I Kr)...
June 14, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28612303/additive-proarrhythmic-effect-of-combined-treatment-with-qt-prolonging-agents
#20
Gerrit Frommeyer, Christina Fischer, Christian Ellermann, Dirk G Dechering, Simon Kochhäuser, Philipp S Lange, Kristina Wasmer, Michael Fehr, Lars Eckardt
Drug combinations may elevate the risk of proarrhythmia. The aim of the present study was to investigate whether combinations of non-cardiovascular agents induce an additive increase in the proarrhythmic risk. In 12 female rabbit hearts, a drug combination of cotrimoxazole (300 µM), ondansetron (5 µM) and domperidone (1 µM) was infused after obtaining baseline data. In another 13 hearts, a combination of cotrimoxazole (300 µM), ondansetron (5 µM) and erythromycin (300 µM) was infused. Monophasic action potentials and ECG displayed a significant QT prolongation in all groups...
June 13, 2017: Cardiovascular Toxicology
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