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https://www.readbyqxmd.com/read/29203397/pro-arrhythmic-effects-of-low-plasma-k-in-human-ventricle-an-illustrated-review
#1
REVIEW
Beatriz Trenor, Karen Cardona, Lucia Romero, Juan F Gomez, Javier Saiz, Sridharan Rajamani, Luiz Belardinelli, Wayne Giles
Potassium levels in the plasma, [K+]o, are regulated precisely under physiological conditions. However, increases (from approx. 4.5 to 8.0mM) can occur as a consequence of, e.g., endurance exercise, ischemic insult or kidney failure. This hyperkalemic modulation of ventricular electrophysiology has been studied extensively. Hypokalemia is also common. It can occur in response to diuretic therapy, following renal dialysis, or during recovery from endurance exercise. In the human ventricle, clinical hypokalemia (e...
November 24, 2017: Trends in Cardiovascular Medicine
https://www.readbyqxmd.com/read/29173399/basic-electrophysiologic-mechanisms-of-sudden-cardiac-death-caused-by-acute-myocardial-ischemia-and-infarction
#2
REVIEW
Andrew L Wit
Sudden cardiac death caused by acute ischemia results from electrophysiologic changes in myocardium deprived of its blood supply. These changes include a reduction in resting potential and phase 0 depolarization and an increase in intercellular resistivity that slow conduction, cause conduction block, and lead to reentrant excitation and ventricular fibrillation. Reperfusion of a coronary artery after a short period of occlusion leads to similar changes.
December 2017: Cardiac Electrophysiology Clinics
https://www.readbyqxmd.com/read/29166279/influence-of-long-term-oral-application-of-quinolones-on-the-ecg-curve-in-dogs
#3
A Cepiel, A Noszczyk-Nowak, A Cekiera, J Popiel, U Pasławska
The aim of the study was to analyse the influence of enrofloxacin and pradofloxacin administered orally for 14 days on the ECG in dogs. The ECG was performed before and after a 14 day period of quinolone administration. There was an increase in the QTc and the TpTe interval in the group treated with quinolones. QTc was prolonged by 24 ms (p=0.001). The TpTe interval was shortened, on average, by 6.55 ms (p=0.048). In the group treated with enrofloxacin, QTc was prolonged by 16.27 ms (p=0.006) and the TpTe interval was shortened by 9...
September 26, 2017: Polish Journal of Veterinary Sciences
https://www.readbyqxmd.com/read/29163179/in-silico-assessment-of-efficacy-and-safety-of-ikur-inhibitors-in-chronic-atrial-fibrillation-role-of-kinetics-and-state-dependence-of-drug-binding
#4
Nicholas Ellinwood, Dobromir Dobrev, Stefano Morotti, Eleonora Grandi
Current pharmacological therapy against atrial fibrillation (AF), the most common cardiac arrhythmia, is limited by moderate efficacy and adverse side effects including ventricular proarrhythmia and organ toxicity. One way to circumvent the former is to target ion channels that are predominantly expressed in atria vs. ventricles, such as KV1.5, carrying the ultra-rapid delayed-rectifier K(+) current (IKur). Recently, we used an in silico strategy to define optimal KV1.5-targeting drug characteristics, including kinetics and state-dependent binding, that maximize AF-selectivity in human atrial cardiomyocytes in normal sinus rhythm (nSR)...
2017: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/29135530/should-percussion-pacing-have-a-role-in-perioperative-advanced-cardiac-life-support-a-case-report
#5
Chris Giordano, Jordan Miller, Ilan Keidan
Percussion pacing involves using one's fist to repeatedly strike a patient's left sternal border in a rhythmic manner. The resulting increase in ventricular pressure can trigger myocardial depolarization and subsequent contraction. We describe the successful treatment of acute preoperative symptomatic sinus bradycardia with percussion pacing in a 63-year-old patient scheduled for placement of a gastric feeding tube after trauma involving spinal cord injury. Although no longer included in current advanced cardiovascular life support guidelines, percussion pacing may be a suitable alternative to chest compressions in multitrauma cases where the force of compressions could cause further complications...
November 9, 2017: A & A Case Reports
https://www.readbyqxmd.com/read/29128504/biophysical-comparison-of-sodium-currents-in-native-cardiac-myocytes-and-human-induced-pluripotent-stem-cell-derived-cardiomyocytes
#6
Robert J Goodrow, Suveer Desai, Jacqueline A Treat, Brian K Panama, Mayurika Desai, Vladislav V Nesterenko, Jonathan M Cordeiro
INTRODUCTION: Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are used for safety pharmacology and to investigate genetic diseases affecting cardiac ion channels. It is unclear whether adult myocytes or hiPSC-CMs are the better platform for cardiac safety pharmacology. We examined the biophysical and molecular properties of INa in adult myocytes and hiPSC-CMs. METHODS: hiPSC-CMs were plated at low density. Atrial and ventricular cells were obtained from dog hearts...
November 8, 2017: Journal of Pharmacological and Toxicological Methods
https://www.readbyqxmd.com/read/29107282/the-autonomic-nervous-system-and-cardiac-glp-1-receptors-control-heart-rate-in-mice
#7
Laurie L Baggio, John R Ussher, Brent A McLean, Xiemin Cao, M Golam Kabir, Erin E Mulvihill, Alexandra S Mighiu, Hangjun Zhang, Andreas Ludwig, Randy J Seeley, Scott P Heximer, Daniel J Drucker
OBJECTIVES: Glucagon-like peptide-1 (GLP-1) is secreted from enteroendocrine cells and exerts a broad number of metabolic actions through activation of a single GLP-1 receptor (GLP-1R). The cardiovascular actions of GLP-1 have garnered increasing attention as GLP-1R agonists are used to treat human subjects with diabetes and obesity that may be at increased risk for development of heart disease. Here we studied mechanisms linking GLP-1R activation to control of heart rate (HR) in mice...
November 2017: Molecular Metabolism
https://www.readbyqxmd.com/read/29091329/repolarization-abnormalities-unmasked-with-exercise-in-sudden-cardiac-death-survivors-with-structurally-normal-hearts
#8
Kevin Mw Leong, Fu Siong Ng, Caroline Roney, Christopher Cantwell, Matthew J Shun-Shin, Nicholas Wf Linton, Zachary I Whinnett, David C Lefroy, D Wyn Davies, Sian E Harding, Phang Boon Lim, Darrel Francis, Nicholas S Peters, Amanda M Varnava, Prapa Kanagaratnam
BACKGROUND: Models of cardiac arrhythmogenesis predict that non-uniformity in repolarization and/or depolarization promotes ventricular fibrillation and is modulated by autonomic tone, but this is difficult to evaluate in patients. We hypothesize that such spatial heterogeneities would be detected by non-invasive ECG imaging (ECGi) in sudden cardiac death (SCD) survivors with structurally normal hearts under physiological stress. METHODS: ECGi was applied to 11 SCD survivors, 10 low-risk Brugada Syndrome patients (BrS) and 10 controls undergoing exercise treadmill testing...
November 1, 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/29075204/human-cardiomyocyte-progenitor-cells-in-co-culture-with-rat-cardiomyocytes-form-a-pro-arrhythmic-substrate-evidence-for-two-different-arrhythmogenic-mechanisms
#9
Nicoline W Smit, Lucia Cócera Ortega, Anna M D Végh, Veronique M F Meijborg, Anke M Smits, Mischa Klerk, Anke J M Tijsen, Hanno L Tan, Marie-José H T Goumans, Gerard J J Boink, Ruben Coronel
Background: Cardiomyocyte progenitor cells (CMPCs) are a promising cell source for regenerative cell therapy to improve cardiac function after myocardial infarction. However, it is unknown whether undifferentiated CMPCs have arrhythmogenic risks. We investigate whether undifferentiated, regionally applied, human fetal CMPCs form a pro-arrhythmic substrate in co-culture with neonatal rat ventricular myocytes (NRVMs). Method: Unipolar extracellular electrograms, derived from micro-electrode arrays (8 × 8 electrodes) containing monolayers of NRVMs (control), or co-cultures of NRVMs and locally seeded CMPCs were used to determine conduction velocity and the incidence of tachy-arrhythmias...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/29072259/barbaloin-inhibits-ventricular-arrhythmias-in-rabbits-by-modulating-voltage-gated-ion-channels
#10
Zhen-Zhen Cao, You-Jia Tian, Jie Hao, Pei-Hua Zhang, Zhi-Pei Liu, Wan-Zhen Jiang, Meng-Liu Zeng, Pei-Pei Zhang, Ji-Hua Ma
Barbaloin (10-β-D-glucopyranosyl-1,8-dihydroxy-3-(hydroxymethyl)-9(10H)-anthracenone) is extracted from the aloe plant and has been reported to have anti-inflammatory, antitumor, antibacterial, and other biological activities. Here, we investigated the effects of barbaloin on cardiac electrophysiology, which has not been reported thus far. Cardiac action potentials (APs) and ionic currents were recorded in isolated rabbit ventricular myocytes using whole-cell patch-clamp technique. Additionally, the antiarrhythmic effect of barbaloin was examined in Langendorff-perfused rabbit hearts...
October 26, 2017: Acta Pharmacologica Sinica
https://www.readbyqxmd.com/read/29066338/electrocardiographic-changes-after-successful-recanalization-of-a-chronic-total-coronary-occlusion-a-systematic-review-and-meta-analysis
#11
REVIEW
Ivo M van Dongen, Joëlle Elias, Veronique M F Meijborg, Jacques M T De Bakker, Jacqueline Limpens, Chantal E Conrath, José P S Henriques
BACKGROUND: Observational studies suggest that in patients with a CTO successful recanalization is associated with better clinical outcome. This could be related to a reduction in the occurrence of arrhythmias, which may result from modifications of the hibernating myocardium in a CTO region. METHODS AND RESULTS: We aimed to evaluate the effect of CTO PCI on electrophysiological parameters, and conducted a systematic review and meta-analysis according to the PRISMA guidelines...
September 12, 2017: Cardiovascular Revascularization Medicine: Including Molecular Interventions
https://www.readbyqxmd.com/read/29029613/right-precordial-directed-electrocardiographical-markers-identify-arrhythmogenic-right-ventricular-cardiomyopathy-in-the-absence-of-conventional-depolarization-or-repolarization-abnormalities
#12
Daniel Cortez, Anneli Svensson, Jonas Carlson, Sharon Graw, Nandita Sharma, Francesca Brun, Anita Spezzacatene, Luisa Mestroni, Pyotr G Platonov
BACKGROUND: Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) carries a risk of sudden death. We aimed to assess whether vectorcardiographic (VCG) parameters directed toward the right heart and a measured angle of the S-wave would help differentiate ARVD/C with otherwise normal electrocardiograms from controls. METHODS: Task Force 2010 definite ARVD/C criteria were met for all patients. Those who did not fulfill Task Force depolarization or repolarization criteria (-ECG) were compared with age and gender-matched control subjects...
October 13, 2017: BMC Cardiovascular Disorders
https://www.readbyqxmd.com/read/29016731/electrical-coupling-between-ventricular-myocytes-and-myofibroblasts-in-the-infarcted-mouse-heart
#13
Michael Rubart, Wen Tao, Xiao-Long Lu, Simon J Conway, Sean P Reuter, Shien-Fong Lin, Mark H Soonpaa
Aims: Recent studies have demonstrated electrotonic coupling between scar tissue and the surrounding myocardium in cryoinjured hearts. However, the electrical dynamics occurring at the myocyte-nonmyocyte interface in the fibrotic heart remain undefined. Here, we sought to develop an assay to interrogate the nonmyocyte cell type contributing to heterocellular coupling and to characterize, on a cellular scale, its voltage response in the infarct border zone of living hearts. Methods and results: We used two-photon laser scanning microscopy in conjunction with a voltage-sensitive dye to record transmembrane voltage changes simultaneously from cardiomyocytes and adjoined nonmyocytes in Langendorff-perfused mouse hearts with healing myocardial infarction...
September 1, 2017: Cardiovascular Research
https://www.readbyqxmd.com/read/28970285/calcium-dependent-arrhythmogenic-foci-created-by-weakly-coupled-myocytes-in-the-failing-heart
#14
Di Lang, Daisuke Sato, Yan Jiang, Kenneth S Ginsburg, Crystal M Ripplinger, Donald M Bers
Rationale: Intercellular uncoupling and Ca mishandling can initiate triggered ventricular arrhythmias. Spontaneous Ca release activates inward current which depolarizes membrane potential (Vm) and can trigger action potentials in isolated myocytes. However, cell-cell coupling in intact hearts limits local depolarization and may protect hearts from this arrhythmogenic mechanism. Traditional optical mapping lacks the spatial resolution to assess coupling of individual myocytes. Objective: We investigate local intercellular coupling in Ca-induced depolarization in intact hearts, using confocal microscopy to measure local Vm and intracellular [Ca(2+)] ([Ca]i) simultaneously...
October 2, 2017: Circulation Research
https://www.readbyqxmd.com/read/28958063/efficacy-of-esmolol-cardioplegia-during-hypothermic-ischaemia
#15
Dai Nishina, David J Chambers
OBJECTIVES: Cardioplegic arrest using a polarizing solution has been shown to have beneficial advantages for cardioprotection compared with depolarizing (potassium-based) arrest; most studies, however, have looked at normothermic ischaemia with short infusion intervals (every 10-15 min). This study examines the protective efficacy of an esmolol-based cardioplegia during hypothermic arrest, together with a prolonged infusion interval (30 min) for increased clinical feasibility. METHODS: Isolated Langendorff-perfused hearts were subjected to arrest with St Thomas' Hospital cardioplegia (STH2), or esmolol cardioplegia (single- or multidose infusion at 32°C) for 60-min, 90-min or 120-min global ischaemia at 32°C, and recovery of function (left ventricular developed pressure) measured...
September 2, 2017: European Journal of Cardio-thoracic Surgery
https://www.readbyqxmd.com/read/28955244/human-in-silico-drug-trials-demonstrate-higher-accuracy-than-animal-models-in-predicting-clinical-pro-arrhythmic-cardiotoxicity
#16
Elisa Passini, Oliver J Britton, Hua Rong Lu, Jutta Rohrbacher, An N Hermans, David J Gallacher, Robert J H Greig, Alfonso Bueno-Orovio, Blanca Rodriguez
Early prediction of cardiotoxicity is critical for drug development. Current animal models raise ethical and translational questions, and have limited accuracy in clinical risk prediction. Human-based computer models constitute a fast, cheap and potentially effective alternative to experimental assays, also facilitating translation to human. Key challenges include consideration of inter-cellular variability in drug responses and integration of computational and experimental methods in safety pharmacology. Our aim is to evaluate the ability of in silico drug trials in populations of human action potential (AP) models to predict clinical risk of drug-induced arrhythmias based on ion channel information, and to compare simulation results against experimental assays commonly used for drug testing...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28948234/mechanisms-underlying-epicardial-radiofrequency-ablation-to-suppress-arrhythmogenesis-in-experimental-models-of-brugada-syndrome
#17
Bence Patocskai, Namsik Yoon, Charles Antzelevitch
OBJECTIVES: This study sought to test the hypothesis that elimination of sites of abnormal repolarization, via epicardial RFA, suppresses the electrocardiographic and arrhythmic manifestations of BrS. BACKGROUND: Brugada syndrome (BrS) is associated with ventricular tachycardia and ventricular fibrillation leading to sudden cardiac death. Nademanee et al. reported that radiofrequency ablation (RFA) of right ventricular outflow tract epicardium significantly reduced the electrocardiogram and arrhythmic manifestations of BrS...
April 2017: JACC. Clinical Electrophysiology
https://www.readbyqxmd.com/read/28939505/impact-of-waterborne-and-trophic-mercury-exposures-on-cardiac-function-of-two-ecologically-distinct-neotropical-freshwater-fish-brycon-amazonicus-and-hoplias-malabaricus
#18
Diana A Monteiro, Edwin W Taylor, Francisco T Rantin, Ana L Kalinin
Metal pollutants have been considered one of the main factors underlying the depletion of biodiversity in natural populations unbalancing aquatic environments. The aim of this study was to evaluate the effects of exposure to inorganic Hg on myocardial contractility and the electrocardiogram (ECG) of two ecologically distinct Neotropical fish species, namely: matrinxã (Brycon amazonicus) and trahira (Hoplias malabaricus). Matrinxãs were exposed to a sublethal concentration of 0.1mgL(-1) of Hg in water for 96h...
September 20, 2017: Comparative Biochemistry and Physiology. Toxicology & Pharmacology: CBP
https://www.readbyqxmd.com/read/28901628/total-cosine-r-to-t-for-predicting-ventricular-arrhythmic-and-mortality-outcomes-a-systematic-review-and-meta-analysis
#19
Gary Tse, Mengqi Gong, Cheuk Wai Wong, Cynthia Chan, Stamatis Georgopoulos, Yat Sun Chan, Bryan P Yan, Guangping Li, Paula Whittaker, Ana Ciobanu, Sadeq Ali-Hasan-Al-Saegh, Sunny H Wong, William K K Wu, George Bazoukis, Konstantinos Lampropoulos, Wing Tak Wong, Lap Ah Tse, Adrian M Baranchuk, Konstantinos P Letsas, Tong Liu
BACKGROUND: The total cosine R-to-T (TCRT), a vectorcardiographic marker reflecting the spatial difference between the depolarization and repolarization wavefronts, has been used to predict ventricular tachycardia/fibrillation (VT/VF) and sudden cardiac death (SCD) in different clinical settings. However, its prognostic value has been controversial. OBJECTIVE: This systematic review and meta-analysis evaluated the significance of TRCT in predicting arrhythmic and/or mortality endpoints...
September 12, 2017: Annals of Noninvasive Electrocardiology
https://www.readbyqxmd.com/read/28877886/pulmonary-right-ventricular-resynchronization-in-congenital-heart-disease-acute-improvement-in-right-ventricular-mechanics-and-contraction-efficiency
#20
Jan Janoušek, Jan Kovanda, Miroslav Ložek, Viktor Tomek, Pavel Vojtovič, Roman Gebauer, Peter Kubuš, Miroslav Krejčíř, Joost Lumens, Tammo Delhaas, Frits Prinzen
BACKGROUND: Electromechanical discoordination may contribute to long-term pulmonary right ventricular (RV) dysfunction in patients after surgery for congenital heart disease. We sought to evaluate changes in RV function after temporary RV cardiac resynchronization therapy. METHODS AND RESULTS: Twenty-five patients aged median 12.0 years after repair of tetralogy of Fallot and similar lesions were studied echocardiographically (n=23) and by cardiac catheterization (n=5) after primary repair (n=4) or after surgical RV revalvulation for significant pulmonary regurgitation (n=21)...
September 2017: Circulation. Cardiovascular Imaging
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