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Cardiac electrophysiology

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https://www.readbyqxmd.com/read/29150791/16-channel-flexible-system-to-measure-electrophysiological-properties-of-bioengineered-hearts
#1
Betsy H Salazar, Kristopher A Hoffman, Anilkumar K Reddy, Sridhar Madala, Ravi K Birla
As tissue engineering continues to mature, it is necessary to develop new technologies that bring insight into current paradigms and guide improvements for future experiments. To this end, we have developed a system to characterize our bioartificial heart model and compare them to functional native structures. In the present study, the hearts of adult Sprague-Dawley were decellularized resulting in a natural three-dimensional cardiac scaffold. Neonatal rat primary cardiac cells were then cultured within a complex 3D fibrin gel, forming a 3-dimensional cardiac construct, which was sutured to the acellular scaffold and suspended in media for 24-48 h...
November 17, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/29146210/novel-intracellular-transport-refractory-mutations-in-kcnh2-identified-in-patients-with-symptomatic-long-qt-syndrome
#2
Daisuke Fukumoto, Wei-Guang Ding, Yuko Wada, Yusuke Fujii, Mari Ichikawa, Koichiro Takayama, Megumi Fukuyama, Koichi Kato, Hideki Itoh, Takeru Makiyama, Mariko Omatsu-Kanbe, Hiroshi Matsuura, Minoru Horie, Seiko Ohno
BACKGROUND: Missense mutations in KCNH2, a gene encoding the Kv11.1 channel, cause long QT syndrome (LQTS) type 2 primarily by disrupting the intracellular transport of Kv11.1 to the plasma membrane. The present study aimed to clarify the functional changes by two novel KCNH2 missense mutations. METHODS: We performed genetic screening of three unrelated symptomatic LQTS probands with family histories of cardiac symptoms. Chinese hamster ovary cells were transfected with wild-type (WT) and/or mutant KCNH2 plasmid and examined by patch-clamp technique...
November 13, 2017: Journal of Cardiology
https://www.readbyqxmd.com/read/29140557/withdrawn-pharmacological-cardioversion-for-atrial-fibrillation-and-flutter
#3
REVIEW
John Cordina, Gillian E Mead
BACKGROUND: Atrial fibrillation is the commonest cardiac dysrhythmia. It is associated with significant morbidity and mortality. There are two approaches to the management of atrial fibrillation: controlling the ventricular rate or converting to sinus rhythm in the expectation that this would abolish its adverse effects. OBJECTIVES: To assess the effects of pharmacological cardioversion of atrial fibrillation in adults on the annual risk of stroke, peripheral embolism, and mortality...
November 15, 2017: Cochrane Database of Systematic Reviews
https://www.readbyqxmd.com/read/29138937/effects-of-propofol-sedation-on-pacing-thresholds-results-from-an-observational-cohort-study
#4
Jakob Lüker, Arian Sultan, Tobias Plenge, Samuel Lee, Jan-Hendrik van den Bruck, Daniel Steven
BACKGROUND: Propofol is one of the most commonly used intravenous anaesthetic drugs for surgical procedures. The use of propofol for sedation is also common practice during endoscopic procedures, electrophysiology studies, and ablation procedures, as well as pacemaker and defibrillator implantation. It was found that propofol alters the electrophysiologic properties of the heart and its conduction system. The effects of propofol on pacing thresholds are unknown and could have implications for pacemaker (PM) and defibrillator (ICD) implantation procedures, as well as sedation and anaesthesia in PM and ICD patients in general...
November 14, 2017: Herzschrittmachertherapie & Elektrophysiologie
https://www.readbyqxmd.com/read/29133340/effects-of-hawthorn-crataegus-pentagyna-leaf-extract-on-electrophysiologic-properties-of-cardiomyocytes-derived-from-human-cardiac-arrhythmia-specific-induced-pluripotent-stem-cells
#5
Sara Pahlavan, Marziyeh Shalchi Tousi, Mahdi Ayyari, Abolfazl Alirezalu, Hassan Ansari, Tomo Saric, Hossein Baharvand
Cardiac arrhythmias are major life-threatening conditions. The landmark discovery of induced pluripotent stem cells has provided a promising in vitro system for modeling hereditary cardiac arrhythmias as well as drug development and toxicity testing. Nowadays, nutraceuticals are frequently used as supplements for cardiovascular therapy. Here we studied the cardiac effects of hawthorn (Crataegus pentagyna) leaf extract using cardiomyocytes (CMs) differentiated from healthy human embryonic stem cells, long QT syndrome type 2 (LQTS2), and catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1) patient-specific induced pluripotent stem cells...
November 13, 2017: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
https://www.readbyqxmd.com/read/29129349/electrical-and-mechanical-alternans-during-ventricular-tachycardia-with-moderate-chronic-heart-failure
#6
Ikeotunye Royal Chinyere, Talal Moukabary, Steven Goldman, Elizabeth Juneman
A chronic heart failure (CHF) rat underwent epicardial programmed electrical stimulation (PES). Ventricular tachycardia (VT) developed during PES. Mechanical alternans was noted despite fixed tachycardia cycle length. Anti-tachycardia pacing attempts initiated a second VT that generated pulse intermittently and then degenerated into pulseless VT with electrical alternans.To our knowledge electrical and mechanical alternans have not been recorded in animal models of CHF during VT. The distinct events of mechanical alternans and electrical alternans may be indicative of progressively worsened calcium handling in the compromised cardiomyocytes...
September 23, 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/29127493/late-sodium-current-associated-cardiac-electrophysiological-and-mechanical-dysfunction
#7
REVIEW
Shandong Yu, Gang Li, Christopher L-H Huang, Ming Lei, Lin Wu
Late sodium current (INaL) is a small sustained inward current observed during the cardiac action potential plateau phase following decay of the early peak INa. The endogenous INaL is relatively small in normal hearts but exerts functionally significant effects on cardiomyocyte repolarization with potentially pro-arrhythmic effects in hearts with reduced repolarization reserve. Enhanced INa,L occurs in long QT syndrome 3 (LQTS 3) patients, and under a number of pathological and pharmacological cardiovascular conditions, including bradycardia, myocardial ischemia, reperfusion injury, and heart failure...
November 10, 2017: Pflügers Archiv: European Journal of Physiology
https://www.readbyqxmd.com/read/29126890/how-to-prevent-recognize-and-manage-complications-of-af-ablation
#8
REVIEW
Mauricio I Scanavacca
Ablation of atrial fibrillation (AF) is one of most complex procedures in electrophysiology. Many technical improvements have been incorporated lately in order to improve clinical results and reducing risks. Currently, cardiac tamponade, stroke, PV stenosis, phrenic palsy and atrial esophageal fistula are still recognized as the major risks of AF ablation, although their managements have been much better established. The aim of this article is to review recent data in how to avoid, to identify and to treat such complications...
November 7, 2017: Portuguese Journal of Cardiology: An Official Journal of the Portuguese Society of Cardiology
https://www.readbyqxmd.com/read/29117223/sensitivity-analysis-revealing-the-effect-of-modulating-ionic-mechanisms-on-calcium-dynamics-in-simulated-human-heart-failure
#9
Maria T Mora, Jose M Ferrero, Lucia Romero, Beatriz Trenor
Abnormal intracellular Ca2+ handling is the major contributor to the depressed cardiac contractility observed in heart failure. The electrophysiological remodeling associated with this pathology alters both the action potential and the Ca2+ dynamics, leading to a defective excitation-contraction coupling that ends in mechanical dysfunction. The importance of maintaining a correct intracellular Ca2+ concentration requires a better understanding of its regulation by ionic mechanisms. To study the electrical activity and ionic homeostasis of failing myocytes, a modified version of the O'Hara et al...
2017: PloS One
https://www.readbyqxmd.com/read/29107716/pacsin-2-is-required-for-the-maintenance-of-a-normal-cardiac-function-in-the-developing-mouse-heart
#10
Judith Semmler, Jan Kormann, Sureshkumar Perumal Srinivasan, Annette Köster, Daniel Sälzer, Michael Reppel, Jürgen Hescheler, Markus Plomann, Filomain Nguemo
The Pacsin proteins (Pacsin 1, 2 and 3) play an important role in intracellular trafficking and thereby signal transduction in many cells types. This study was designed to examine the role of Pacsin 2 in cardiac development and function. We investigated the development and electrophysiological properties of Pacsin 2 knockout (P2KO) hearts and single cardiomyocytes isolated from 11.5 and 15.5days old fetal mice. Immunofluorescence experiments confirmed the lack of Pacsin 2 protein expression in P2KO cardiac myocytes in comparison to wildtype (WT)...
October 28, 2017: Pharmacological Research: the Official Journal of the Italian Pharmacological Society
https://www.readbyqxmd.com/read/29101167/transient-denervation-of-viable-myocardium-after-myocardial-infarction-does-not-alter-arrhythmia-susceptibility
#11
Diana C Parrish, Samantha D Francis Stuart, Antoinette Olivas, Lianguo Wang, Anders Nykjaer, Crystal May Ripplinger, Beth Ann Habecker
Cardiac sympathetic nerves stimulate heart rate and force of contraction. Myocardial infarction (MI) leads to the loss of sympathetic nerves within the heart, and clinical studies indicate that sympathetic denervation is a risk factor for arrhythmias and cardiac arrest. Two distinct types of denervation have been identified in the mouse heart after MI caused by ischemia-reperfusion: transient denervation of peri-infarct myocardium, and sustained denervation of the infarct. Sustained denervation is linked to increased arrhythmia risk, but it is not known if acute nerve loss in peri-infarct myocardium also contributes to arrhythmia risk...
November 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29097318/systematic-review-for-the-2017-aha-acc-hrs-guideline-for-management-of-patients-with-ventricular-arrhythmias-and-the-prevention-of-sudden-cardiac-death-a-report-of-the-american-college-of-cardiology-american-heart-association-task-force-on-clinical-practice
#12
Fred M Kusumoto, Kent R Bailey, Ahmad Sami Chaouki, Abhishek J Deshmukh, Sandeep Gautam, Robert J Kim, Daniel B Kramer, Litsa K Lambrakos, Naseer H Nasser, Dan Sorajja
BACKGROUND: Although large randomized clinical trials have found that primary prevention use of an implantable cardioverter-defibrillator (ICD) improves survival in patients with cardiomyopathy and heart failure symptoms, patients who receive ICDs in practice are often older and have more comorbidities than patients who were enrolled in the clinical trials. In addition, there is a debate among clinicians on the usefulness of electrophysiological study for risk stratification of asymptomatic patients with Brugada syndrome...
October 25, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/29097297/systematic-review-for-the-2017-aha-acc-hrs-guideline-for-management-of-patients-with-ventricular-arrhythmias-and-the-prevention-of-sudden-cardiac-death-a-report-of-the-american-college-of-cardiology-american-heart-association-task-force-on-clinical-practice
#13
Fred M Kusumoto, Kent R Bailey, Ahmad Sami Chaouki, Abhishek J Deshmukh, Sandeep Gautam, Robert J Kim, Daniel B Kramer, Litsa K Lambrakos, Naseer H Nasser, Dan Sorajja
BACKGROUND: Although large randomized clinical trials have found that primary prevention use of an implantable cardioverter-defibrillator (ICD) improves survival in patients with cardiomyopathy and heart failure symptoms, patients who receive ICDs in practice are often older and have more comorbidities than patients who were enrolled in the clinical trials. In addition, there is a debate among clinicians on the usefulness of electrophysiological study for risk stratification of asymptomatic patients with Brugada syndrome...
October 24, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/29097067/contemporary-review-of-left-bundle-branch-block-in-the-failing-heart-pathogenesis-prognosis-and-therapy
#14
REVIEW
Juliana Kanawati, Raymond W Sy
Cardiac resynchronisation therapy (CRT) is a cornerstone in the contemporary management of heart failure. The most effective way of predicting response to this therapy remains electrocardiographic (ECG) criteria of electromechanical dyssynchrony. The left bundle branch block (LBBB) pattern is currently the most robust ECG criterion in predicting improvement in symptoms and reduction in mortality. However, recent studies using three-dimensional (3D) mapping and cardiac magnetic resonance imaging (CMR) have demonstrated heterogeneous left ventricular activation patterns in patients with LBBB...
October 6, 2017: Heart, Lung & Circulation
https://www.readbyqxmd.com/read/29091329/repolarization-abnormalities-unmasked-with-exercise-in-sudden-cardiac-death-survivors-with-structurally-normal-hearts
#15
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/29089383/herg1a-and-herg1b-potassium-channel-subunits-directly-interact-and-preferentially-form-heteromeric-channels
#16
Beth A McNally, Zeus Pendon, Matthew C Trudeau
Voltage-activated human ether-a-go-go related gene (hERG) potassium channels are critical for the repolarization of cardiac action potentials and tune-spike frequency adaptation in neurons. Two isoforms of mammalian ERG1 channel subunits, ERG1a and ERG1b, are the principal subunits that conduct the IKr current in the heart and are also broadly expressed in the nervous system. However, there is little direct evidence that ERG1a and ERG1b form heteromeric channels. Here, using electrophysiology, biochemistry, and fluorescence approaches, we systematically tested for direct interactions between hERG1a and hERG1b subunits...
October 31, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29081906/brugada-type-1-electrocardiogram-should-we-treat-the-electrocardiogram-or-the-patient
#17
REVIEW
Pietro Delise, Giuseppe Allocca, Nadir Sitta
Patients with a Brugada type 1 electrocardiogram (ECG) pattern may suffer sudden cardiac death (SCD). Recognized risk factors are spontaneous type 1 ECG and syncope of presumed arrhythmic origin. Familial sudden cardiac death (f-SCD) is not a recognized independent risk factor. Finally, positive electrophysiologic study (+EPS) has a controversial prognostic value. Current ESC guidelines recommend implantable cardioverter defibrillator (ICD) implantation in patients with a Brugada type 1 ECG pattern if they have suffered a previous resuscitated cardiac arrest (class I recommendation) or if they have syncope of presumed cardiac origin (class IIa recommendation)...
September 26, 2017: World Journal of Cardiology
https://www.readbyqxmd.com/read/29079665/cardiac-magnetic-resonance-for-lesion-assessment-in-the-electrophysiology-laboratory
#18
EDITORIAL
Timothy M Markman, Saman Nazarian
No abstract text is available yet for this article.
November 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/29079077/non-ion-channel-therapeutics-for-heart-failure-and-atrial-fibrillation-are-camkii-inhibitors-ready-for-clinical-use-editorial-on-neef-s-steffens-a-pellicena-p-mustroph-j-lebek-s-ort-kr-schulman-h-maier-ls-improvement-of-cardiomyocyte-function-by-a-novel-pyrimidine
#19
EDITORIAL
Eleonora Grandi, Dobromir Dobrev
The Ca(2+)-calmodulin dependent protein kinase II (CaMKII) is an established central mediator of electrophysiological and contractile responses to cardiac stress, and its hyper-activation in cardiac diseases has been linked to heart failure (HF) and atrial and ventricular arrhythmias. Here we summarize the evidence supporting the role of CaMKII as a critical nodal point for therapeutic intervention against HF and atrial and ventricular tachyarrhythmias. Targeting of CaMKII in heart with inhibitors possessing appropriate selectivity might represent a novel therapeutic approach for HF and arrhythmias...
October 24, 2017: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/29072259/barbaloin-inhibits-ventricular-arrhythmias-in-rabbits-by-modulating-voltage-gated-ion-channels
#20
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
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