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Ventricular depolarization

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https://www.readbyqxmd.com/read/28509708/pvcs-pvc-induced-cardiomyopathy-and-the-role-of-catheter-ablation
#1
Esseim Sharma, Karuppiah Arunachalam, Mengyang Di, Antony Chu, Abhishek Maan
Premature ventricular contractions (PVCs) are common arrhythmias noticed in the clinical setting because of premature depolarization of the ventricular myocytes. Although often thought to be reflective of underlying disease rather than intrinsically harmful, PVCs have recently been linked with worse outcomes in patients without significant cardiac disease. Long-term exposure to a high PVC burden can lead to the development of PVC-induced cardiomyopathy. The pathogenesis of this condition is poorly understood at the current time...
June 2017: Critical Pathways in Cardiology
https://www.readbyqxmd.com/read/28507060/alogliptin-a-dipeptidyl-peptidase-4-inhibitor-alleviates-atrial-remodeling-and-improves-mitochondrial-function-and-biogenesis-in-diabetic-rabbits
#2
Xiaowei Zhang, Zhiwei Zhang, Yungang Zhao, Ning Jiang, Jiuchun Qiu, Yajuan Yang, Jian Li, Xue Liang, Xinghua Wang, Gary Tse, Guangping Li, Tong Liu
BACKGROUND: There is increasing evidence implicating atrial mitochondrial dysfunction in the pathogenesis of atrial fibrillation. In this study, we explored whether alogliptin, a dipeptidyl peptidase-4 inhibitor, can prevent mitochondrial dysfunction and atrial remodeling in a diabetic rabbit model. METHODS AND RESULTS: A total of 90 rabbits were randomized into 3 groups as follows: control group (n=30), alloxan-induced diabetes mellitus group (n=30), and alogliptin-treated (12...
May 15, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/28500173/tgf-%C3%AE-1-transforming-growth-factor-%C3%AE-1-plays-a-pivotal-role-in-cardiac-myofibroblast-arrhythmogenicity
#3
Nicolò Salvarani, Ange Maguy, Stefano A De Simone, Michele Miragoli, Florian Jousset, Stephan Rohr
BACKGROUND: TGF-β1 (transforming growth factor-β1) importantly contributes to cardiac fibrosis by controlling differentiation, migration, and collagen secretion of cardiac myofibroblasts. It is still elusive, however, to which extent TGF-β1 alters the electrophysiological phenotype of myofibroblasts and cardiomyocytes and whether it affects proarrhythmic myofibroblast-cardiomyocyte crosstalk observed in vitro. METHODS AND RESULTS: Patch-clamp recordings of cultured neonatal rat ventricular myofibroblasts revealed that TGF-β1, applied for 24 to 48 hours at clinically relevant concentrations (≤2...
May 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/28484842/conventional-mapping-and-ablation-of-focal-ventricular-tachycardias-in-the-healthy-heart
#4
REVIEW
Sonia Busch, Johannes Brachmann, Ahmed Saleh, Mathias Forkmann
Ventricular tachycardias (VT) in the healthy heart, also known as idiopathic VTs, often have a focal origin. Triggered activity due to delayed after-depolarization is the most likely mechanism of focal VTs. Localization of the site of origin of focal VTs is based on activation mapping with or without combination with pace mapping. The characteristic anatomic site of origin of idiopathic VTs is the right and left outflow tract. Other sites include the tricuspid and mitral annulus, the papillary muscles, and Purkinje fibers...
May 8, 2017: Herzschrittmachertherapie & Elektrophysiologie
https://www.readbyqxmd.com/read/28484841/-bundle-branch-reentry-vt-diagnosis-mapping-and-ablation
#5
REVIEW
Christopher Reithmann
Macroreentry in the His-Purkinje system can result in sustained ventricular tachycardia (VT) termed bundle branch reentry VT. Bundle branch reentry is usually associated with His-Purkinje disease and depressed left ventricular function. In the case of typical bundle branch reentry, the right bundle is activated in the anterograde direction and ventricular depolarization begins at the distal end of the right bundle on the ventricular septum generating a typical left bundle branch block QRS morphology. However, atypical surface ECGs can also be found in patients with severe left ventricular dysfunction and involvement of the right ventricle complicating the diagnosis of bundle branch reentry VT...
May 8, 2017: Herzschrittmachertherapie & Elektrophysiologie
https://www.readbyqxmd.com/read/28468664/twenty-four-hour-ambulatory-electrocardiography-characterization-of-heart-rhythm-in-vipera-berus-envenomed-dogs
#6
Anna Rave Vestberg, Anna Tidholm, Ingrid Ljungvall
BACKGROUND: Vipera berus has a worldwide distribution and causes high morbidity in dogs annually. A complication to envenomation may be cardiac arrhythmias. The purpose of this study was to investigate the prevalence, types, and timing of arrhythmias, using 24-h ambulatory electrocardiography (24-AECG), in dogs bitten by V. berus in the first 24-32 h after envenomation. In addition, this study aimed to investigate if there were differences in selected clinical and hematological- and biochemical variables (including cardiac troponin I) at admission between V...
May 3, 2017: Acta Veterinaria Scandinavica
https://www.readbyqxmd.com/read/28458554/patient-characteristics-associated-with-false-arrhythmia-alarms-in-intensive-care
#7
Patricia R Harris, Jessica K Zègre-Hemsey, Daniel Schindler, Yong Bai, Michele M Pelter, Xiao Hu
INTRODUCTION: A high rate of false arrhythmia alarms in the intensive care unit (ICU) leads to alarm fatigue, the condition of desensitization and potentially inappropriate silencing of alarms due to frequent invalid and nonactionable alarms, often referred to as false alarms. OBJECTIVE: The aim of this study was to identify patient characteristics, such as gender, age, body mass index, and diagnosis associated with frequent false arrhythmia alarms in the ICU. METHODS: This descriptive, observational study prospectively enrolled patients who were consecutively admitted to one of five adult ICUs (77 beds) at an urban medical center over a period of 31 days in 2013...
2017: Therapeutics and Clinical Risk Management
https://www.readbyqxmd.com/read/28456609/computational-modeling-for-cardiac-safety-pharmacology-analysis-contribution-of-fibroblasts
#8
Xin Gao, Tylor Engel, Brian E Carlson, Tetsuro Wakatsuki
INTRODUCTION: Drug-induced proarrhythmic potential is an important regulatory criterion in safety pharmacology. The application of in silico approaches to predict proarrhythmic potential of new compounds is under consideration as part of future guidelines. Current approaches simulate electrophysiology of a single human adult ventricular cardiomyocyte. However, drug-induced proarrhythmic potential can be different when cardiomyocytes are surrounded by non-muscle cells. Incorporating fibroblasts in models of myocardium is important particularly for predicting a drugs cardiac liability in the aging population - a growing population who take more medications and exhibit increased cardiac fibrosis...
April 26, 2017: Journal of Pharmacological and Toxicological Methods
https://www.readbyqxmd.com/read/28444176/-j-waves-induced-after-short-coupling-intervals-a-manifestations-of-latent-depolarization-abnormality
#9
Yoshifusa Aizawa, Masafumi Nakayama, Masahito Sato, Masaaki Okabe, Yoshiyasu Aizawa, Seiji Takatsuki, Keiichi Fukuda
Aims: To confirm the presence of tachycardia-induced slur or notch in the terminal portion of the QRS complexes in a general patient population. Methods and results: A tachycardia-induced J wave was defined as a slur or notch in the terminal portion of the QRS complexes newly induced at short RR intervals during atrial premature contractions (APCs) or atrial electrical stimulation in the electrophysiological study (EPS). Twenty-three out of 2000 patients with general diseases were involved...
April 24, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28396856/bidomain-predictions-of-virtual-electrode-induced-make-and-break-excitations-around-blood-vessels
#10
Adam J Connolly, Edward Vigmond, Martin J Bishop
INTRODUCTION AND BACKGROUND: Virtual electrodes formed by field stimulation during defibrillation of cardiac tissue play an important role in eliciting activations. It has been suggested that the coronary vasculature is an important source of virtual electrodes, especially during low-energy defibrillation. This work aims to further the understanding of how virtual electrodes from the coronary vasculature influence defibrillation outcomes. METHODS: Using the bidomain model, we investigated how field stimulation elicited activations from virtual electrodes around idealized intramural blood vessels...
2017: Frontiers in Bioengineering and Biotechnology
https://www.readbyqxmd.com/read/28395022/optogenetic-manipulation-of-anatomical-re-entry-by-light-guided-generation-of-a-reversible-local-conduction-block
#11
Masaya Watanabe, Iolanda Feola, Rupamanjari Majumder, Wanchana Jangsangthong, Alexander S Teplenin, Dirk L Ypey, Martin J Schalij, Katja Zeppenfeld, Antoine A F de Vries, Daniël A Pijnappels
Aims: Anatomical re-entry is an important mechanism of ventricular tachycardia, characterized by circular electrical propagation in a fixed pathway. It's current investigative and therapeutic approaches are non-biological, rather unspecific (drugs), traumatizing (electrical shocks), or irreversible (ablation). Optogenetics is a new biological technique that allows reversible modulation of electrical function with unmatched spatiotemporal precision using light-gated ion channels. We therefore investigated optogenetic manipulation of anatomical re-entry in ventricular cardiac tissue...
March 1, 2017: Cardiovascular Research
https://www.readbyqxmd.com/read/28382321/electrophysiological-mechanisms-of-long-and-short-qt-syndromes
#12
REVIEW
Gary Tse, Yin Wah Fiona Chan, Wendy Keung, Bryan P Yan
The QT interval on the human electrocardiogram is normally in the order of 450 ms, and reflects the summated durations of action potential (AP) depolarization and repolarization of ventricular myocytes. Both prolongation and shortening in the QT interval have been associated with ventricular tachy-arrhythmias, which predispose affected individuals to sudden cardiac death. In this article, the molecular determinants of the AP duration and the causes of long and short QT syndromes (LQTS and SQTS) are explored...
March 2017: IJC Heart & Vasculature
https://www.readbyqxmd.com/read/28381122/argon-exposure-induces-postconditioning-in-myocardial-ischemia-reperfusion
#13
Sandrine Lemoine, Katrien Blanchart, Mathieu Souplis, Adrien Lemaitre, Damien Legallois, Laurent Coulbault, Christophe Simard, Stéphane Allouche, Jacques H Abraini, Jean-Luc Hanouz, René Rouet, Laurent Sallé, Romain Guinamard, Alain Manrique
BACKGROUND AND PURPOSE: Cardioprotection against ischemia-reperfusion (I/R) damages remains a major concern during prehospital management of acute myocardial infarction. Noble gases have shown beneficial effects in preconditioning studies. Because emergency proceedings in the context of myocardial infarction require postconditioning strategies, we evaluated the effects of argon in such protocols on mammalian cardiac tissue. EXPERIMENTAL APPROACHES: In rat, cardiac I/R was induced in vivo by transient coronary artery ligature and cardiac functions were evaluated by magnetic resonance imaging...
January 1, 2017: Journal of Cardiovascular Pharmacology and Therapeutics
https://www.readbyqxmd.com/read/28367337/premature-ventricular-complex-causing-ice-pick-headache
#14
Selcuk Ozturk, Ertan Yetkin
Ice pick headache is a momentary, transient, repetitive headache disorder and manifests with the stabbing pains and jolts. The exact mechanism causing this disease is unknown. Premature ventricular contractions are early depolarization of the ventricular myocardium and in the absence of a structural heart disease, it is considered to be a benign disease. In this report, we describe a male patient presenting with the symptom of momentary headache attacks accompanied with instant chest pain which is associated with premature ventricular contraction...
2017: Case Reports in Cardiology
https://www.readbyqxmd.com/read/28336184/atrial-fibrillation-management-in-a-breeding-stallion
#15
N Heliczer, K Mitchell, O Lorello, J Dauvillier, D Burger, C C Schwarzwald, C Navas de Solis
A 20-year-old warmblood breeding stallion presented to a University practice for semen collection and evaluation was incidentally diagnosed with atrial fibrillation (AF). Electrocardiogram recordings during breeding revealed inappropriately rapid tachycardia and occasional ventricular premature depolarizations/aberrant ventricular conduction. Transvenous electrical cardioversion was performed. After successful cardioversion the horse displayed supraventricular ectopy and atrial contractile dysfunction and was administered sotalol hydrochloride in an attempt to decrease the risk of AF recurrence...
March 20, 2017: Journal of Veterinary Cardiology: the Official Journal of the European Society of Veterinary Cardiology
https://www.readbyqxmd.com/read/28329148/myocardial-energy-metabolism-and-ultrastructure-with-polarizing-and-depolarizing-cardioplegia-in-a-porcine-model%C3%A2
#16
Terje Aass, Lodve Stangeland, David J Chambers, Seth Hallström, Christine Rossmann, Bruno K Podesser, Malte Urban, Knut Nesheim, Rune Haaverstad, Knut Matre, Ketil Grong
OBJECTIVES: This study investigated whether the novel St. Thomas' Hospital polarizing cardioplegic solution (STH-POL) with esmolol/adenosine/magnesium offers improved myocardial protection by reducing demands for high-energy phosphates during cardiac arrest compared to the depolarizing St. Thomas' Hospital cardioplegic solution No 2 (STH-2). METHODS: Twenty anaesthetised pigs on tepid cardiopulmonary bypass were randomized to cardiac arrest for 60 min with antegrade freshly mixed, repeated, cold, oxygenated STH-POL or STH-2 blood cardioplegia every 20 min...
March 2, 2017: European Journal of Cardio-thoracic Surgery
https://www.readbyqxmd.com/read/28294644/electrocardiogram-changes-and-atrial-arrhythmias-in-individuals-carrying-sodium-channel-scn5a-d1275n-mutation
#17
Sari U M Vanninen, Kjell Nikus, Katriina Aalto-Setälä
INTRODUCTION: The cardiac sodium channel SCN5A regulates atrioventricular and ventricular depolarization as well as cardiac conduction. Patients with cardiac electrical abnormalities have an increased risk of sudden cardiac death (SCD) and cardio-embolic stroke. Optimal management of cardiac disease includes the understanding of association between the causative mutations and the clinical phenotype. A 12-lead electrocardiogram (ECG) is an easy and inexpensive tool for finding risk patients...
March 15, 2017: Annals of Medicine
https://www.readbyqxmd.com/read/28265681/ischemia-induced-drp1-and-fis1-mediated-mitochondrial-fission-and-right-ventricular-dysfunction-in-pulmonary-hypertension
#18
Lian Tian, Monica Neuber-Hess, Jeffrey Mewburn, Asish Dasgupta, Kimberly Dunham-Snary, Danchen Wu, Kuang-Hueih Chen, Zhigang Hong, Willard W Sharp, Shelby Kutty, Stephen L Archer
Right ventricular (RV) function determines prognosis in pulmonary arterial hypertension (PAH). We hypothesize that ischemia causes RV dysfunction in PAH by triggering dynamin-related protein 1 (Drp1)-mediated mitochondrial fission. RV function was compared in control rats (n = 50) versus rats with monocrotaline-induced PAH (MCT-PAH; n = 60) both in vivo (echocardiography) and ex vivo (RV Langendorff). Mitochondrial membrane potential and morphology and RV function were assessed before or after 2 cycles of ischemia-reperfusion injury challenge (RV-IR)...
April 2017: Journal of Molecular Medicine: Official Organ of the "Gesellschaft Deutscher Naturforscher und Ärzte"
https://www.readbyqxmd.com/read/28262340/gain-of-function-mutation-in-scn5a-causes-ventricular-arrhythmias-and-early-onset-atrial-fibrillation
#19
Krystien V Lieve, Arie O Verkerk, Svitlana Podliesna, Christian van der Werf, Michael W Tanck, Nynke Hofman, Paul F van Bergen, Leander Beekman, Connie R Bezzina, Arthur A M Wilde, Elisabeth M Lodder
BACKGROUND: Mutations in SCN5A, the gene encoding the α-subunit of the cardiac sodium channel (NaV1.5), are associated with a broad spectrum of inherited cardiac arrhythmia disorders. The purpose of this study was to identify the genetic and functional determinants underlying a Dutch family that presented with a combined phenotype of ventricular arrhythmias with a likely adrenergic component, either in isolation or in combination with a mildly decreased heart function and early onset (<55years) atrial fibrillation...
January 29, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28262257/t-wave-axis-deviation-and-qrs-t-angle-controversial-indicators-of-incident-coronary-heart-events
#20
REVIEW
Polychronis Dilaveris, Christos-Konstantinos Antoniou, Konstantinos Gatzoulis, Dimitrios Tousoulis
Abnormal orientation of the T-wave axis and increased angle between the QRS complex (depolarization) and the T-wave (repolarization) have long been assumed to provide a global measure of repolarization abnormality, and have been used to assess ventricular repolarization. The ability of the T wave axis deviation and the QRS-T angle to predict incident coronary heart events was examined in several studies. However, conflicting results have led to significant controversy in the literature concerning their purported ability...
February 20, 2017: Journal of Electrocardiology
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