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https://www.readbyqxmd.com/read/28821956/effects-of-ageing-on-pro-arrhythmic-ventricular-phenotypes-in-incrementally-paced-murine-pgc-1%C3%AE-hearts
#1
Shiraz Ahmad, Haseeb Valli, Charlotte E Edling, Andrew A Grace, Kamalan Jeevaratnam, Christopher L-H Huang
A range of chronic clinical conditions accompany cardiomyocyte energetic dysfunction and constitute independent risk factors for cardiac arrhythmia. We investigated pro-arrhythmic and arrhythmic phenotypes in energetically deficient C57BL mice with genetic ablation of the mitochondrial promoter peroxisome proliferator-activated receptor-γ coactivator-1β (Pgc-1β), a known model of ventricular arrhythmia. Pro-arrhythmic and cellular action potential (AP) characteristics were compared in intact Langendorff-perfused hearts from young (12-16 week) and aged (> 52 week), wild-type (WT) and Pgc-1β (-/-) mice...
August 18, 2017: Pflügers Archiv: European Journal of Physiology
https://www.readbyqxmd.com/read/28821732/light-color-importance-for-circadian-entrainment-in-a-diurnal-octodon-degus-and-a-nocturnal-rattus-norvegicus-rodent
#2
Maria Angeles Bonmati-Carrion, Beatriz Baño-Otalora, Juan Antonio Madrid, Maria Angeles Rol
The central circadian pacemaker (Suprachiasmatic Nuclei, SCN) maintains the phase relationship with the external world thanks to the light/dark cycle. Light intensity, spectra, and timing are important for SCN synchronisation. Exposure to blue-light at night leads to circadian misalignment that could be avoided by using less circadian-disruptive wavelengths. This study tests the capacity of a diurnal Octodon degus and nocturnal Rattus norvegicus to synchronise to different nocturnal lights. Animals were subjected to combined red-green-blue lights (RGB) during the day and to: darkness; red light (R); combined red-green LED (RG) lights; and combined red-green-violet LED (RGV) lights during the night...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28818964/caffeine-does-not-increase-the-arrhythmic-burden-in-patients-with-heart-failure-and-left-ventricular-systolic-dysfunction
#3
Daniel Caldeira
No abstract text is available yet for this article.
August 17, 2017: Evidence-based Medicine
https://www.readbyqxmd.com/read/28818088/assessment-of-the-effect-of-left-atrial-cryoablation-enhanced-by-ganglionated-plexi-ablation-in-the-treatment-of-atrial-fibrillation-in-patients-undergoing-open-heart-surgery
#4
Jiří Bárta, Radim Brát
BACKGROUND: The aim of our study was to investigate, whether enhancement of left atrial cryoablation by ablation of the autonomic nervous system of left atrium leads to influencing the outcomes of surgical treatment of atrial fibrillation in patients with structural heart disease undergoing open-heart surgery. METHODS: The observed patient file consisted of 100 patients, who have undergone a combined open-heart surgery at our department between July 2012 and December 2014...
August 17, 2017: Journal of Cardiothoracic Surgery
https://www.readbyqxmd.com/read/28816086/inducible-knockout-of-mouse-zfhx3-emphasizes-its-key-role-in-setting-the-pace-and-amplitude-of-the-adult-circadian-clock
#5
Ashleigh G Wilcox, Lucie Vizor, Michael J Parsons, Gareth Banks, Patrick M Nolan
The transcription factor zinc finger homeobox 3 (ZFHX3) plays a key role in coupling intracellular transcriptional-translational oscillations with intercellular synchrony in mouse suprachiasmatic nucleus (SCN). However, like many key players in central nervous system function, ZFHX3 serves an important role in neurulation and neuronal terminal differentiation while retaining discrete additional functions in the adult SCN. Recently, using a dominant missense mutation in mouse Zfhx3, we established that this gene can modify circadian period and sleep in adult animals...
August 1, 2017: Journal of Biological Rhythms
https://www.readbyqxmd.com/read/28815597/cardiac-action-potential-repolarization-re-visited-early-repolarization-shows-all-or-none-behaviour
#6
Beatriz Trenor, Karen Cardona, Javier Saiz, Denis Noble, Wayne Giles
In healthy mammalian hearts the action potential (AP) waveform initiates and modulates each contraction, or heartbeat. As a result, action potential height and duration are key physiological variables. In addition, rate-dependent changes in ventricular action potential duration (APD), and variations in APD at a fixed heart rate, are both reliable biomarkers of electrophysiological stability. Present guidelines for the likelihood that candidate drugs will increase arrhythmias rely on small changes in APD and Q-T intervals as criteria for Safety Pharmacology decisions...
August 17, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28814790/in-silico-investigation-of-a-kcnq1-mutation-associated-with-short-qt-syndrome
#7
Ismail Adeniran, Dominic G Whittaker, Aziza El Harchi, Jules C Hancox, Henggui Zhang
Short QT syndrome (SQTS) is a rare condition characterized by abnormally 'short' QT intervals on the ECG and increased susceptibility to cardiac arrhythmias and sudden death. This simulation study investigated arrhythmia dynamics in multi-scale human ventricle models associated with the SQT2-related V307L KCNQ1 'gain-of-function' mutation, which increases slow-delayed rectifier potassium current (IKs). A Markov chain (MC) model recapitulating wild type (WT) and V307L mutant IKs kinetics was incorporated into a model of the human ventricular action potential (AP) for investigation of QT interval changes and arrhythmia substrates...
August 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28808023/prefrontal-cortex-modulates-posterior-alpha-oscillations-during-top-down-guided-visual-perception
#8
Randolph F Helfrich, Melody Huang, Guy Wilson, Robert T Knight
Conscious visual perception is proposed to arise from the selective synchronization of functionally specialized but widely distributed cortical areas. It has been suggested that different frequency bands index distinct canonical computations. Here, we probed visual perception on a fine-grained temporal scale to study the oscillatory dynamics supporting prefrontal-dependent sensory processing. We tested whether a predictive context that was embedded in a rapid visual stream modulated the perception of a subsequent near-threshold target...
August 14, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28807565/disrupted-day-night-pattern-of-cardiovascular-death-in-obstructive-sleep-apnea
#9
Emerson Ferreira Martins, Denis Martinez, Fernando A Boeira Sabino da Silva, Lauren Sezerá, Rodrigo da Rosa de Camargo, Cintia Zappe Fiori, Flávio Danni Fuchs, Ruy Silveira Moraes
BACKGROUND: Obstructive sleep apnea (OSA) patients who suffer sudden cardiac death die predominantly during the night. We aimed to investigate whether all cardiovascular-related deaths display the same night-time peak as sudden cardiac death. METHODS: Data from a large cohort of adults who underwent full-night polysomnography between 1985 and 2015 in a university-affiliated sleep clinic were analyzed. Time and cause of death of these patients and of persons from the general population were identified in death certificates from the State Health Secretariat...
July 26, 2017: Sleep Medicine
https://www.readbyqxmd.com/read/28804678/capacitively-coupled-arrays-of-multiplexed-flexible-silicon-transistors-for-long-term-cardiac-electrophysiology
#10
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/28803778/an-unstable-singularity-underlies-stochastic-phasing-of-the-circadian-clock-in-individual-cyanobacterial-cells
#11
Siting Gan, Erin K O'Shea
The endogenous circadian clock synchronizes with environmental time by appropriately resetting its phase in response to external cues. Of note, some resetting stimuli induce attenuated oscillations of clock output, which has been observed at the population-level in several organisms and in studies of individual humans. To investigate what is happening in individual cellular clocks, we studied the unicellular cyanobacterium S. elongatus. By measuring its phase-resetting responses to temperature changes, we found that population-level arrhythmicity occurs when certain perturbations cause stochastic phases of oscillations in individual cells...
August 17, 2017: Molecular Cell
https://www.readbyqxmd.com/read/28802040/aged-stem-cells-reprogram-their-daily-rhythmic-functions-to-adapt-to-stress
#12
Guiomar Solanas, Francisca Oliveira Peixoto, Eusebio Perdiguero, Mercè Jardí, Vanessa Ruiz-Bonilla, Debayan Datta, Aikaterini Symeonidi, Andrés Castellanos, Patrick-Simon Welz, Juan Martín Caballero, Paolo Sassone-Corsi, Pura Muñoz-Cánoves, Salvador Aznar Benitah
Normal homeostatic functions of adult stem cells have rhythmic daily oscillations that are believed to become arrhythmic during aging. Unexpectedly, we find that aged mice remain behaviorally circadian and that their epidermal and muscle stem cells retain a robustly rhythmic core circadian machinery. However, the oscillating transcriptome is extensively reprogrammed in aged stem cells, switching from genes involved in homeostasis to those involved in tissue-specific stresses, such as DNA damage or inefficient autophagy...
August 10, 2017: Cell
https://www.readbyqxmd.com/read/28794139/denervated-myocardium-is-preferentially-associated-with-sudden-cardiac-arrest-in-ischemic-cardiomyopathy-a-pilot-competing-risks-analysis-of-cause-specific-mortality
#13
James A Fallavollita, Jonathan D Dare, Randolph L Carter, Sunil Baldwa, John M Canty
BACKGROUND: Previous studies have identified multiple risk factors that are associated with total cardiac mortality. Nevertheless, identifying specific factors that distinguish patients at risk of arrhythmic death versus heart failure could better target patients likely to benefit from implantable cardiac defibrillators, which have no impact on nonsudden cardiac death. METHODS AND RESULTS: We performed a pilot competing risks analysis of the National Institutes of Health-sponsored PAREPET trial (Prediction of Arrhythmic Events with Positron Emission Tomography)...
August 2017: Circulation. Cardiovascular Imaging
https://www.readbyqxmd.com/read/28789916/flecainide-reduces-ventricular-arrhythmias-in-patients-with-genotype-ryr2-positive-catecholaminergic-polymorphic-ventricular-tachycardia
#14
Fernando Wangüemert Pérez, Julio Salvador Hernández Afonso, María Del Val Groba Marco, Eduardo Caballero Dorta, Luis Álvarez Acosta, Oscar Campuzano Larrea, Guillermo Pérez, Josep Brugada Terradellas, Ramón Brugada Terradellas
INTRODUCTION AND OBJECTIVES: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited disease characterized by polymorphic or bidirectional ventricular arrhythmias (VA) triggered by physical or emotional stress in young people with a structurally normal heart. Beta-blockers are the cornerstone of treatment, while flecainide has recently been incorporated into the therapeutic arsenal. The aim of this study was to report our experience with this drug. METHODS: The cohort included 174 genotype-positive CPVT-patients from 7 families...
August 5, 2017: Revista Española de Cardiología
https://www.readbyqxmd.com/read/28780194/scar-characterization-to-predict-life-threatening-arrhythmic-events-and%C3%A2-sudden-cardiac-death-in-patients-with-cardiac-resynchronization-therapy-the-gaudi-crt-study
#15
Juan Acosta, Juan Fernández-Armenta, Roger Borràs, Ignasi Anguera, Felipe Bisbal, Julio Martí-Almor, Jose M Tolosana, Diego Penela, David Andreu, David Soto-Iglesias, Reinder Evertz, María Matiello, Concepción Alonso, Roger Villuendas, Teresa M de Caralt, Rosario J Perea, Jose T Ortiz, Xavier Bosch, Luis Serra, Xavier Planes, Andreas Greiser, Okan Ekinci, Luis Lasalvia, Lluis Mont, Antonio Berruezo
OBJECTIVES: The aim of this study was to analyze whether scar characterization could improve the risk stratification for life-threatening ventricular arrhythmias and sudden cardiac death (SCD). BACKGROUND: Among patients with a cardiac resynchronization therapy (CRT) indication, appropriate defibrillator (CRT-D) therapy rates are low. METHODS: Primary prevention patients with a class I indication for CRT were prospectively enrolled and assigned to CRT-D or CRT pacemaker according to physician's criteria...
July 28, 2017: JACC. Cardiovascular Imaging
https://www.readbyqxmd.com/read/28766881/angiographic-and-clinical-performance-of-polymer-free-biolimus-eluting-stent-in-patients-with-st-segment-elevation-acute-myocardial-infarction-in-a-metropolitan-public-hospital-the-besami-mucho-study
#16
Gregory A Sgueglia, Fabrizio D'Errico, Gaetano Gioffrè, Antonella De Santis, Francesco Summaria, Fabiana Piccioni, Achille Gaspardone
OBJECTIVES: This study aimed at assessing the performance of a new generation polymer-free biolimus-eluting stent (BES) in real-world patients with ST-segment elevation myocardial infarction (STEMI). BACKGROUND: Polymers components of early-generation drug-eluting stents have been implicated in the pathogenesis of delayed arterial healing, vessel remodeling, and delayed stent thrombosis. Recently, a novel polymer-free BES has shown excellent clinical performance in clinical trial setting...
August 2, 2017: Catheterization and Cardiovascular Interventions
https://www.readbyqxmd.com/read/28766047/prognostic-value-of-cardiovascular-magnetic-resonance-imaging-for-life-threatening-arrhythmia-detected-by-implantable-cardioverter-defibrillator-in-japanese-patients-with-hypertrophic-cardiomyopathy
#17
Yasuki Hen, Mayuko Tsugu-Yagawa, Nobuo Iguchi, Yuko Utanohara, Kaori Takada, Haruhiko Machida, Ayako Takara, Kunihiko Teraoka, Kanki Inoue, Itaru Takamisawa, Morimasa Takayama, Tsutomu Yoshikawa
Implantable cardioverter-defibrillator (ICD) is effective to prevent sudden death in HCM patients. We reviewed ICD records to analyze the relation between life-threatening arrhythmia and late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) in Japanese hypertrophic cardiomyopathy (HCM) patients. In 102 consecutive patients (median age 63 years, 63 males) implanted with an ICD after CMR with gadolinium enhancement (median follow-up 2.8 years), the outcome of life-threatening arrhythmic events (appropriate ICD interventions for ventricular tachycardia or ventricular fibrillation) was examined...
August 1, 2017: Heart and Vessels
https://www.readbyqxmd.com/read/28761607/-severe-ventricular-arrhythmias-in-a-patient-with-dilated-cardiomyopathy-and-automated-implantable-defibrillator-aid
#18
Stéphane Méo Ikama, Jospin Makani, Bertrand Ellenga-Mbolla, Louis Igor Ondze-Kafata, Thierry Raoul Gombet, Gisèle Kimbally-Kaky
Severe ventricular arrhythmias are frequent during heart failure; they are a life-threatening condition due to the increased risk of sudden death. Efficient management remains limited in sub-Saharan Africa because of the limited or unavailable medical resources as automated implantable defibrillator (AID). We report the case of a 56-year old patient with non ischemic dilated cardiomyopathy with very low left ventricular ejection fraction (LVEF)who underwent AID implantation for primary prevention of sudden cardiac death due to ventricular arrhythmias in 2012...
2017: Pan African Medical Journal
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
#19
RANDOMIZED CONTROLLED TRIAL
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/28756098/phenotypic-variability-in-lqt3-human-induced-pluripotent-stem-cell-derived-cardiomyocytes-and-their-response-to-antiarrhythmic-pharmacologic-therapy-an-in-silico-approach
#20
Michelangelo Paci, Elisa Passini, Stefano Severi, Jari Hyttinen, Blanca Rodriguez
BACKGROUND: Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are in vitro models with the clear advantages of their human origin and suitability for human disease investigations. However, limitations include their incomplete characterization and variability reported in different cell lines and laboratories. OBJECTIVE: The purpose of this study was to investigate in silico ionic mechanisms potentially explaining the phenotypic variability of hiPSC-CMs in long QT syndrome type 3 (LQT3) and their response to antiarrhythmic drugs...
July 27, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
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