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Cardiac electrophysiology

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https://www.readbyqxmd.com/read/28804678/capacitively-coupled-arrays-of-multiplexed-flexible-silicon-transistors-for-long-term-cardiac-electrophysiology
#1
Hui Fang, Ki Jun Yu, Christopher Gloschat, Zijian Yang, Chia-Han Chiang, Jianing Zhao, Sang Min Won, Siyi Xu, Michael Trumpis, Yiding Zhong, Enming Song, Seung Won Han, Yeguang Xue, Dong Xu, Gert Cauwenberghs, Matthew Kay, Yonggang Huang, Jonathan Viventi, Igor R Efimov, John A Rogers
Advanced capabilities in electrical recording are essential for the treatment of heart-rhythm diseases. The most advanced technologies use flexible integrated electronics; however, the penetration of biological fluids into the underlying electronics and any ensuing electrochemical reactions pose significant safety risks. Here, we show that an ultrathin, leakage-free, biocompatible dielectric layer can completely seal an underlying layer of flexible electronics while allowing for electrophysiological measurements through capacitive coupling between tissue and the electronics, and thus without the need for direct metal contact...
2017: Nature biomedical engineering
https://www.readbyqxmd.com/read/28803619/basis-and-ecg-measurement-of-global-ventricular-repolarization
#2
Robert L Lux
Ventricular repolarization and its manifestation in the T wave of the electrocardiogram have long been a focus of clinical and experimental electrocardiology. In this short article, we shall review the basics of cellular and organ repolarization electrophysiology, the classical and emerging methods of measuring global repolarization, and methodology that relates directly measured cardiac indices of repolarization to the body surface electrocardiogram.
July 12, 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/28801548/virtual-cardiac-monolayers-for-electrical-wave-propagation
#3
Nina Kudryashova, Valeriya Tsvelaya, Konstantin Agladze, Alexander Panfilov
The complex structure of cardiac tissue is considered to be one of the main determinants of an arrhythmogenic substrate. This study is aimed at developing the first mathematical model to describe the formation of cardiac tissue, using a joint in silico-in vitro approach. First, we performed experiments under various conditions to carefully characterise the morphology of cardiac tissue in a culture of neonatal rat ventricular cells. We considered two cell types, namely, cardiomyocytes and fibroblasts. Next, we proposed a mathematical model, based on the Glazier-Graner-Hogeweg model, which is widely used in tissue growth studies...
August 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28800884/ionic-mechanisms-of-the-action-of-anaesthetics-on-sinoatrial-node-automaticity
#4
REVIEW
Akiko Kojima, Hiroshi Matsuura
Although various general anaesthetics affect the heart rate in clinical settings, their precise mechanisms remain to be fully elucidated. Because the heart rate is determined by automaticity of the cardiac pacemaker sinoatrial node and its regulation by autonomic nervous system, it is important to clarify the effect of anaesthetics on sinoatrial node automaticity. The spontaneous electrical activity of sinoatrial node is generated by a complex but coordinated interaction of multiple ionic currents, such as the hyperpolarisation-activated cation current (If), T-type and L-type Ca(2+) currents (ICa,T and ICa,L), Na(+)/Ca(2+) exchange current (INCX), and rapidly and slowly activating delayed rectifier K(+) currents (IKr and IKs)...
August 8, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28800128/adult-cardiac-stem-cells-are-multipotent-and-robustly-myogenic-c-kit-expression-is-necessary-but-not-sufficient-for-their-identification
#5
Carla Vicinanza, Iolanda Aquila, Mariangela Scalise, Francesca Cristiano, Fabiola Marino, Eleonora Cianflone, Teresa Mancuso, Pina Marotta, Walter Sacco, Fiona C Lewis, Liam Couch, Victoria Shone, Giulia Gritti, Annalaura Torella, Andrew J Smith, Cesare Mn Terracciano, Domenico Britti, Pierangelo Veltri, Ciro Indolfi, Bernardo Nadal-Ginard, Georgina M Ellison-Hughes, Daniele Torella
Multipotent adult resident cardiac stem cells (CSCs) were first identified by the expression of c-kit, the stem cell factor receptor. However, in the adult myocardium c-kit alone cannot distinguish CSCs from other c-kit-expressing (c-kit(pos)) cells. The adult heart indeed contains a heterogeneous mixture of c-kit(pos) cells, mainly composed of mast and endothelial/progenitor cells. This heterogeneity of cardiac c-kit(pos) cells has generated confusion and controversy about the existence and role of CSCs in the adult heart...
August 11, 2017: Cell Death and Differentiation
https://www.readbyqxmd.com/read/28798965/increased-afterload-following-myocardial-infarction-promotes-conduction-dependent-arrhythmias-that-are-unmasked-by-hypokalemia
#6
Lukas J Motloch, Kiyotake Ishikawa, Chaoqin Xie, Jun Hu, Jaume Aguero, Kenneth M Fish, Roger J Hajjar, Fadi G Akar
Although the pathophysiological significance of resistant hypertension in post-myocardial infarction (MI) patients is established, mechanisms by which increased afterload in that setting worsens outcome are unclear. With regards to sudden cardiac death, whether increased afterload alters the electrophysiological substrate following MI is unknown. We established a new large animal model of chronic post-MI remodeling with increased afterload which exhibits widespread deposition of fibrosis in remote areas from the anterior MI, mimicking the disease phenotype of patients with advanced ischemic heart disease...
June 2017: JACC. Basic to Translational Science
https://www.readbyqxmd.com/read/28791747/ecg-morphology-of-premature-ventricular-contractions-predicts-presence-of-myocardial-fibrotic-substrate-on-cardiac-magnetic-resonance-imaging-in-patients-undergoing-ablation
#7
Sabrina Oebel, Borislav Dinov, Arash Arya, Sebastian Hilbert, Philipp Sommer, Andreas Bollmann, Gerhard Hindricks, Ingo Paetsch, Cosima Jahnke
BACKGROUND: The most likely origin of PVCs may be deduced from surface ECG analysis while planning an electrophysiological study (EPS). Apart from purely benign forms of increased ventricular ectopy, myocardial substrate (e.g., regional fibrosis) may be present in certain cases, which will significantly impact the ablation approach. CMR imaging can reliably identify fibrotic target lesions and, hence, may assist in adequate patient selection and procedural planning. METHODS AND RESULTS: We analyzed 101 patients (59% male, mean age 57...
August 9, 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/28790436/three-tf-co-expression-modules-regulate-pressure-overload-cardiac-hypertrophy-in-male-mice
#8
Yao-Ming Chang, Li Ling, Ya-Ting Chang, Yu-Wang Chang, Wen-Hsiung Li, Arthur Chun-Chieh Shih, Chien-Chang Chen
Pathological cardiac hypertrophy, a dynamic remodeling process, is a major risk factor for heart failure. Although a number of key regulators and related genes have been identified, how the transcription factors (TFs) dynamically regulate the associated genes and control the morphological and electrophysiological changes during the hypertrophic process are still largely unknown. In this study, we obtained the time-course transcriptomes at five time points in four weeks from male murine hearts subjected to transverse aorta banding surgery...
August 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28782569/the-protective-effects-of-electro-acupuncture-in-thoracic-surgery-on-trauma-stressed-rats-involve-the-rostral-ventrolateral-medulla-and-supraoptic-nucleus
#9
Huan-Huan Zhang, Yi-Nan Tao, Mei-Yan Jiang, Jin Wang, Jun Chen, Chun-Mei Xia, Lin-Lin Shen, Meng-Ya Wang, Da-Nian Zhu
The present study was designed to explore whether the rostral ventrolateral medulla (RVLM) and supraoptic nucleus (SON) were involved in the protective effects of electro-acupuncture (EA) on cardiac function in thoracic surgery on trauma-stressed rats. The rats were randomly divided into a non-stressed group (Control), surgical trauma-stressed group (Trauma), and Neiguan EA applied on the surgical trauma-stressed group (Trauma+EA-PC 6). RVLM neuron discharge was observed by using an in vivo electrophysiological method, and micro-dialysis combining high-performance liquid chromatography with fluorometric detection (HPLC-FD) was used to assess expression of amino acids in the RVLM...
August 3, 2017: Brain Research Bulletin
https://www.readbyqxmd.com/read/28780623/effect-of-a-photosensitization-reaction-performed-during-the-first-3%C3%A2-min-after-exposure-of-rat-myocardial-cells-to-talaporfin-sodium-in-vitro
#10
Marika Doi, Emiyu Ogawa, Tsunenori Arai
To better understand the mechanism of photodynamic cardiac ablation, we studied the effects of a photosensitization reaction (PR) performed during the first 3 min after rat myocardial cells were exposed to talaporfin sodium. A 3-mm-square microelectrode array with 64 electrodes was used to continuously measure the action potentials of the myocardial cells. A 30 μg/mL talaporfin sodium solution, a chlorine photosensitizer, was used, along with a 663-nm red diode laser (86 mW/cm(2) for up to 600 s). The first trough of the measured action potential waveform corresponding to Na(+) dynamics decreased exponentially with increasing PR duration...
August 5, 2017: Lasers in Medical Science
https://www.readbyqxmd.com/read/28780600/the-anti-influenza-drug-oseltamivir-reduces-atrial-fibrillation-in-an-experimental-whole-heart-model
#11
Gerrit Frommeyer, André Mittelstedt, Julian Wolfes, Christian Ellermann, Simon Kochhäuser, Patrick Leitz, Dirk G Dechering, Lars Eckardt
Recent experimental studies suggested direct effects of the anti-influenza drug oseltamivir on cardiac electrophysiology. We therefore aimed at analyzing potential antiarrhythmic effects of oseltamivir on atrial fibrillation (AF) in an experimental whole-heart model. Twelve rabbit hearts were isolated and Langendorff perfused. Thereafter, hearts were paced at cycle lengths of 350, 250, and 200 ms in the atrium. A standardized protocol employing atrial burst pacing induced AF in 4 of 12 hearts under baseline conditions (33%, 11 episodes)...
August 6, 2017: Naunyn-Schmiedeberg's Archives of Pharmacology
https://www.readbyqxmd.com/read/28777443/use-of-human-pluripotent-stem-cell-derived-cardiomyocytes-to-study-drug-induced-cardiotoxicity
#12
Agnes Maillet, Kim Peng Tan, Liam R Brunham
Drug-induced cardiotoxicity is the one of the most common causes of drug withdrawal from market. A major barrier in managing the risk of drug-induced cardiotoxicity has been the lack of relevant models to study cardiac safety. Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) have great potential in drug discovery and cardiotoxcity screens as they display many characteristics of the human myocardium and offer unlimited supply. This unit describes how to use pluripotent stem cells derived cardiomyocytes to study drug-induced cardiotoxicty using doxorubicin as an example...
August 4, 2017: Current Protocols in Toxicology
https://www.readbyqxmd.com/read/28776823/mri-of-patients-with-implanted-cardiac-devices
#13
REVIEW
Bobby Kalb, Julia H Indik, Peter Ott, Diego R Martin
Cardiac implanted electronic devices (CIEDs) have historically been regarded as a contraindication for performing magnetic resonance imaging (MRI), limiting the availability of this exam for large numbers of patients who may have otherwise benefited from the unique diagnostic capabilities of MRI. Interactions between CIEDs and the magnetic field associated with MRI systems have been documented, and include potential effects on CIED function, lead heating, and force/torque on the generator. Several device manufacturers have developed "MR-Conditional" CIEDs with specific hardware and software design changes to optimize the device for the MR environment...
August 4, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28769025/delayed-pacemaker-generator-pocket-and-lead-primary-infection-due-to-burkholderia-cepacia
#14
Fatma Ben Abid, Hussam Al-Saoub, Faraj Howadi, Ahmed AlBishawi, Maliha Thapur
BACKGROUND Recently, the use of cardiac implantable electrophysiological devices (CIEDs) has increased. Advances in medical technology, an increasingly aging population, increases in clinical indications, and expanded medical insurance coverage for these devices have all contributed to this trend. Infection is considered to be one of the most serious complications of CIEDs and carries a significant risk of morbidity and mortality. Although infection with Staphylococcus sp. accounts for the majority of cases, other bacteria have been implicated as causative agents of infection of CIEDs...
August 3, 2017: American Journal of Case Reports
https://www.readbyqxmd.com/read/28766834/transseptal-puncture-using-surgical-electrocautery-in-children-and-adults-with-and-without-complex-congenital-heart-disease
#15
Srinath T Gowda, Athar M Qureshi, Daniel Turner, Nitin Madan, Justin Weigand, Richard Lorber, Harinder R Singh
BACKGROUND: Atrial transseptal puncture (TSP) for cardiac catheterization procedures remain challenging in children and adults with complex congenital heart disease (CHD). OBJECTIVES: We sought to evaluate our experience using radiofrequency (RF) current via surgical electrocautery needle for TSP to facilitate diagnostic and interventional procedures. METHODS: Retrospective chart review of all patients (pts) who underwent TSP using RF energy (10-25 W) via surgical electrocautery from three centers from January 2011 to January 2017 were evaluated...
August 2, 2017: Catheterization and Cardiovascular Interventions
https://www.readbyqxmd.com/read/28766006/tissue-level-cardiac-electrophysiology-studied-in-murine-myocardium-using-a-microelectrode-array-autonomic-and-thermal-modulation
#16
Jem D Lane, David Montaigne, Andrew Tinker
Cardiac electrophysiology is regulated by the autonomic nervous system, and this has both pathophysiological, and possibly therapeutic importance. Furthermore, chamber differences in electrophysiology exist between atria and ventricles, yet there have been few direct comparisons. There is substantial literature on ion channel modulation at the single-cell level but less work on how this affects tissue-level parameters. We used a microelectrode array system to explore these issues using murine atrial and ventricular tissue slices...
August 1, 2017: Journal of Membrane Biology
https://www.readbyqxmd.com/read/28762918/-noninvasive-electrophysiological-mapping-in-patients-with-complete-left-bundle-branch-block-and-different-modes-of-biventricular-pacing
#17
S V Zubarev, M P Chmelevsky, M A Budanova, M A Trukshina, T A Lyubimtseva, V K Lebedeva, D S Lebedev
OBJECTIVE: to investigate possibilities of noninvasive electrophysiological mapping (NEM) during biventricular (BiV) pacing and to compare the results with data of 12 lead ECG and tissue Doppler echocardiography (TDI). MATERIAL AND METHODS: The study included 25 patients with complete left bundle branch block (LBBB) and implanted cardiac resynchronization therapy (CRT) system. Twenty-two patients were CRT responders, three other patients did not demonstrate a clear effect...
May 2017: Kardiologiia
https://www.readbyqxmd.com/read/28760211/implantable-cardiac-monitors-in-high-risk-post-infarction-patients-with-cardiac-autonomic-dysfunction-and-moderately-reduced-left-ventricular-ejection-fraction-design-and-rationale-of-the-smart-mi-trial
#18
Wolfgang Hamm, Konstantinos D Rizas, Lukas von Stülpnagel, Nikolay Vdovin, Steffen Massberg, Stefan Kääb, Axel Bauer
BACKGROUND: Most deaths after myocardial infarction (MI) occur in patients with left ventricular ejection fraction (LVEF) >35%, for whom no specific prophylactic strategies exist. Deceleration capacity (DC) of heart rate and periodic repolarization dynamics (PRD) are noninvasive electrophysiological markers depending on the vagal and sympathetic tone. The combination of abnormal DC and/or PRD identifies a new high-risk group among postinfarction patients with LVEF 36%-50%. This new high-risk group has similar characteristics with respect to prognosis and patient numbers to those of the established high-risk group identified by LVEF ≤ 35%...
August 2017: American Heart Journal
https://www.readbyqxmd.com/read/28757278/distribution-and-chronotropic-effects-of-serotonin-in-the-zebrafish-heart
#19
Matthew R Stoyek, Michael G Jonz, Frank M Smith, Roger P Croll
Several lines of evidence suggest that serotonin (5-HT) has a regulatory role in cardiovascular function from embryogenesis through adulthood. However, the reported actions of 5-HT are often contradictory and include bradycardia or tachycardia, hypotension or hypertension, and vasodilation or vasoconstriction. Clarifying such cardiac effects requires further research and may benefit from utilizing a model simpler than the mammalian hearts traditionally used in these studies. In the present study, we describe the cardiac distribution and chronotropic responses of 5-HT in the zebrafish heart...
September 2017: Autonomic Neuroscience: Basic & Clinical
https://www.readbyqxmd.com/read/28757154/the-central-serotonin2b-receptor-as-a-new-pharmacological-target-for-the-treatment-of-dopamine-related-neuropsychiatric-disorders-rationale-and-current-status-of-research
#20
REVIEW
Céline Devroye, Adeline Cathala, Pier Vincenzo Piazza, Umberto Spampinato
The serotonin2B receptor (5-HT2BR), which was first cloned and characterized in the rat stomach fundus, is the most recent addition to the 5-HT2R family. While its involvement in the regulation of gastrointestinal, vascular, pulmonary and cardiac physiology has been widely investigated, its functional role within the central nervous system (CNS) has received much less attention. Nevertheless, when considering the data available in the literature with regards to the regulatory control exerted by the central 5-HT2BR on dopamine (DA) and serotonin (5-HT) neuron activity, a very interesting picture emerges and highlights the key role of these receptors for future therapeutic strategies of DA-related neuropsychiatric disorders...
July 27, 2017: Pharmacology & Therapeutics
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