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https://www.readbyqxmd.com/read/29223114/regional-conduction-velocity-calculation-from-clinical-multichannel-electrograms-in-human-atria
#1
Bhawna Verma, Tobias Oesterlein, Axel Loewe, Armin Luik, Claus Schmitt, Olaf Dössel
BACKGROUND: During atrial fibrillation, heterogeneities and anisotropies result in a chaotic propagation of the depolarization wavefront. The electrophysiological parameter called conduction velocity (CV) influences the propagation pattern over the atrium. We present a method that determines the regional CV for deformed catheter shapes, which result due to the catheter movement and changing wall contact. METHODS: The algorithm selects stable catheter positions, finds the local activation times (LAT), considers the wall contact and calculates all CV estimates within the area covered by the catheter...
November 26, 2017: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/29218016/synergistic-anti-arrhythmic-effects-in-human-atria-with-combined-use-of-sodium-blockers-and-acacetin
#2
Haibo Ni, Dominic G Whittaker, Wei Wang, Wayne R Giles, Sanjiv M Narayan, Henggui Zhang
Atrial fibrillation (AF) is the most common cardiac arrhythmia. Developing effective and safe anti-AF drugs remains an unmet challenge. Simultaneous block of both atrial-specific ultra-rapid delayed rectifier potassium (K+) current (IKur) and the Na+ current (INa) has been hypothesized to be anti-AF, without inducing significant QT prolongation and ventricular side effects. However, the antiarrhythmic advantage of simultaneously blocking these two channels vs. individual block in the setting of AF-induced electrical remodeling remains to be documented...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/29216985/eplerenone-reduces-atrial-fibrillation-burden-without-preventing-atrial%C3%A2-electrical-remodeling
#3
Yoshio Takemoto, Rafael J Ramirez, Kuljeet Kaur, Oscar Salvador-Montañés, Daniela Ponce-Balbuena, Roberto Ramos-Mondragón, Steven R Ennis, Guadalupe Guerrero-Serna, Omer Berenfeld, José Jalife
BACKGROUND: The aldosterone inhibitor eplerenone (EPL) has been shown to reduce the incidence of atrial fibrillation (AF) in patients with systolic heart failure, but the mechanism is unknown. OBJECTIVES: This study hypothesized that by reducing atrial dilation and fibrosis in the absence of heart failure, EPL also reduces AF burden and prevents AF perpetuation. METHODS: The authors conducted a randomized controlled study in 34 sheep that were atrially tachypaced (13 ± 1 week)...
December 12, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/29174249/low-interatrial-septal-pacing-a-simple-method
#4
Asit Das, Dhiman Kahali, Shibananda Dutta
BACKGROUND: Sinus node disease is associated with widespread structural and electrophysiological changes in the atria in addition to abnormalities at the sinus node. The atrial conduction disorder in patients with atrial pacing results in higher incidence of atrial fibrillation. Studies have shown that low interatrial septal pacing is superior to right atrial appendage pacing in preventing persistent or permanent atrial fibrillation in these patients. However, implantation of active fixation lead in low interatrial septal position is difficult and time consuming with conventional stylet, inhibiting application of this method in routine practice...
November 2017: Indian Heart Journal
https://www.readbyqxmd.com/read/29166718/-value-of-two-left-atrium-and-pulmonary-vein-stereoscopic-imaging-reconstruction-methods-on-guiding-radiofrequency-ablation-for-atrial-fibrillation
#5
Y Tian, S Zhou, Y H Yin, Y X Zheng, R P Wang, X Q Liu, Z Q Liu, Q F Liu, W Liu, J Pang, Z Jiang, L H Tian, J Huang, L Yang
Objective: To compare the value of two 3D imaging reconstruction methods for left atria and pulmonary vein on guiding the catheter ablation for atrial fibrillation (AF). Methods: From January 2014 to January 2017, a total of 100 drug refractory paroxysmal AF patients were divided into left atria direct angiography group (n=50), and indirect angiography group (n=50). 3D CARTO system was applied for mapping and guiding the ablation procedure. Patients assigned to direct angiography group were treated as follows: intraoperative puncture of atrial septum, inject contrast agent directly into the left atrium, conduct left atrial and pulmonary venous rotation angiography, reconstruct three-dimensional image, integrate the image into real-time X-ray system to facilitate circumferential pulmonary vein isolation...
November 24, 2017: Zhonghua Xin Xue Guan Bing za Zhi
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
#6
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/29159313/fibrosis-and-atrial-fibrillation-computerized-and-optical-mapping-a-view-into-the-human-atria-at-submillimeter-resolution
#7
Brian J Hansen, Jichao Zhao, Vadim V Fedorov
Recent studies strongly suggest that the majority of atrial fibrillation (AF) patients with diagnosed or subclinical cardiac diseases have established or even pre-existing fibrotic structural remodeling, which may lead to conduction abnormalities and reentrant activity that sustain AF. As conventional treatments fail to treat AF in far too many cases, an urgent need exists to identify specific structural arrhythmogenic fibrosis patterns, which may maintain AF, in order to identify effective ablation targets for AF treatment...
June 2017: JACC. Clinical Electrophysiology
https://www.readbyqxmd.com/read/29146482/impaired-left-atrial-strain-as-a-predictor-of-new-onset-atrial-fibrillation-after-aortic-valve-replacement-independently-of-left-atrial-size
#8
Guilherme Pessoa-Amorim, Jennifer Mancio, Luís Vouga, José Ribeiro, Vasco Gama, Nuno Bettencourt, Ricardo Fontes-Carvalho
INTRODUCTION AND OBJECTIVES: Left atrial dysfunction in aortic stenosis may precede atrial enlargement and predict the occurrence of atrial fibrillation (AF). To test this hypothesis, we assessed left atrial function and determined its impact on the incidence of AF after aortic valve replacement. METHODS: A total of 149 severe aortic stenosis patients (74±8.6 years, 51% men) with no prior AF were assessed using speckle-tracking echocardiography. Left atrial function was evaluated using peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS), and phasic left atrial volumes...
November 13, 2017: Revista Española de Cardiología
https://www.readbyqxmd.com/read/29146153/the-stress-kinase-jnk-regulates-gap-junction-cx43-gene-expression-and-promotes-atrial-fibrillation-in-the-aged-heart
#9
Jiajie Yan, Justin K Thomson, Weiwei Zhao, Xiaomin Wu, Xianlong Gao, Dominic DeMarco, Wei Kong, Min Tong, Jun Sun, Mamdouh Bakhos, Vladimir G Fast, Qingrong Liang, Sumanth D Prabhu, Xun Ai
BACKGROUND: The stress kinase c-jun N-terminal kinase (JNK) is critical in the pathogenesis of cardiac diseases associated with an increased incidence of atrial fibrillation (AF), the most common arrhythmia in the elderly. We recently discovered that JNK activation is linked to the loss of gap junction connexin43 (Cx43) and enhanced atrial arrhythmogenicity. However, direct evidence for JNK-mediated impairment of intercellular coupling (cell-cell communication) in the intact aged atrium is lacking, as is evidence for whether and how JNK suppresses Cx43 in the aged human atrium...
November 13, 2017: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/29133182/a-novel-method-for-localization-and-ablation-of-conduction-gaps-after-wide-antral-circumferential-ablation-of-pulmonary-veins
#10
Raoul Bacquelin, Raphaël P Martins, Nathalie Behar, Vincent Galand, Baptiste Polin, Jonathan Lacaze, Frédéric Sebag, Christophe Leclercq, Jean-Claude Daubert, Philippe Mabo, Dominique Pavin
BACKGROUND: Atrial fibrillation ablation is often performed by achieving pulmonary vein isolation using the "wide antral circumferential ablation" (WACA) technique, but many pulmonary veins remain connected because of conduction gaps in the ablation line. AIM: To analyse the efficacy of a novel technique based on pacing manoeuvres to detect gaps in an initial WACA lesion. METHODS: Patients referred for radiofrequency atrial fibrillation ablation were enrolled prospectively...
November 10, 2017: Archives of Cardiovascular Diseases
https://www.readbyqxmd.com/read/29131288/mechanisms-of-cardioembolic-stroke-revisited-atrial-cardiopathy
#11
Justyna Mączyńska, Iwona Kurkowska-Jastrzębska, Rafał Dąbrowski
There has been only moderate progress in our understanding of potential relation between atrial arrhythmia and stroke over years. Current approach is still based on a hypothesis that atrial contractile dysfunction due to fibrillation causes blood stasis, which accompanied by other factors acting together as Virchow's triad produces thrombus and embolism to the brain. In this review we would like to discuss a relatively new concept of atrial cardiopathy. It assumes that risk of thromboembolism is increased regardless of atrial rhythm, being largely driven by atrial tissue abnormalities, such as fibrosis, endothelial and myocytes dysfunction and atrial dilatation...
November 13, 2017: Kardiologia Polska
https://www.readbyqxmd.com/read/29120873/a-rare-case-of-isolated-atrial-myocarditis-causing-death-with-no-post-mortem-computed-tomography-scan-correlation
#12
Rexson Tse, Jack Garland, Kilak Kesha, Yvonne Triggs, Lucy Modahl, David Milne, Zhi Yap, Simon Stables
Acute myocarditis is a potentially fatal cardiac pathology that is thought to cause sudden death through arrhythmia and cardiac failure. Of the different subtypes, lymphocytic myocarditis is the most common form. The pathophysiology of myocarditis can be generally diffuse or focally involve the ventricles, but less frequently affects the atria. Although the clinical literature reports isolated atrial myocarditis as a cause of atrial fibrillation and enlargement, there is scant postmortem literature on the findings of this pathology...
November 9, 2017: American Journal of Forensic Medicine and Pathology
https://www.readbyqxmd.com/read/29101618/%C3%AE-adrenergic-stimulation-induces-pro-arrhythmic-activity-in-the-caval-vein-myocardial-tissue
#13
A D Ivanova, V S Kuzmin, L V Rosenshtraukh
Electrical activity of the right superior vena cava (SVC) is considered as a source of the atrial fibrillation. We have shown that bioelectrical properties of the SVC myocardium differ from those of the working atrial myocardium. Electrically evoked action potential duration in SVC is significantly shorter, the resting membrane potential in both stimulated and quiescent SVC preparations is significantly more positive than in atria. Activation of β-adrenoreceptors in SVC myocardium leads to a series of action potentials, and this process depends on protein kinase A...
September 2017: Doklady Biological Sciences: Proceedings of the Academy of Sciences of the USSR, Biological Sciences Sections
https://www.readbyqxmd.com/read/29101544/anatomy-of-the-atria-a%C3%A2-road-map-to-the-left-atrial-appendage
#14
REVIEW
Umberto Barbero, Siew Yen Ho
The left atrial appendage (LAA) has received increasing attention in recent years because of thrombi formation in patients with atrial fibrillation, which increases the risk of stroke. In patients who have contraindications for long-term oral anticoagulation therapy, percutaneous procedures are used to occlude the LAA and there are now several devices available for implantation, both endocardially and epicardially. Despite the high-resolution imaging techniques on hand today, limitations remain in providing information about wall thickness and neighboring structures; therefore, in-depth knowledge of the normal atrial anatomy is mandatory when considering such interventions...
November 3, 2017: Herzschrittmachertherapie & Elektrophysiologie
https://www.readbyqxmd.com/read/29098615/the-benefits-of-exercise-training-on-aerobic-capacity-in-patients-with-heart-failure-and-preserved-ejection-fraction
#15
Danilo Marcelo Leite do Prado, Enéas Antônio Rocco
Heart failure with preserved ejection fraction (HFpEF) is defined as an inability of the ventricles to optimally accept blood from atria with blunted end- diastolic volume response by limiting the stroke volume and cardiac output. The HEpEF prevalence is higher in elderly and women and may be associated to hypertension, diabetes mellitus and atrial fibrillation. Severe exercise intolerance, manifested by dyspnea and fatigue during physical effort is the important chronic symptom in HFpEF patients, in which is the major determinant of their reduced quality of life...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/29097705/metoprolol-prevents-chronic-obstructive-sleep-apnea-induced-atrial-fibrillation-by-inhibiting-structural-sympathetic-nervous-and-metabolic-remodeling-of-the-atria
#16
Li Sun, Sen Yan, Xiaoyu Wang, Shiqi Zhao, Hui Li, Yike Wang, Shuang Lu, Xinwen Dong, Jing Zhao, Shengzhu Yu, Minghui Li, Yue Li
Chronic obstructive sleep apnea (OSA) may promote the development of atrial fibrillation (AF) by inducing atrial electrical and structural remodeling as well as autonomic nerve hyperinnervation. Here, we investigated the roles of metoprolol in regulation of atrial remodeling induced by chronic OSA. A canine model of chronic OSA was established by stopping the ventilator and closing the airway for 4 h/day every other day for 12 weeks, while metoprolol (5 mg·kg-1·day-1) was continuously administered. Using that model, we observed that increases in sympathetic sprouting and atrial structural remodeling were sharply inhibited by metoprolol...
November 2, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29057224/commentary-atrial-fibrillation-dynamics-and-ionic-block-effects-in-six-heterogeneous-human-3d-virtual-atria-with-distinct-repolarization-dynamics
#17
COMMENT
Chiara Campana, Fadi G Akar
No abstract text is available yet for this article.
2017: Frontiers in Bioengineering and Biotechnology
https://www.readbyqxmd.com/read/29044861/comparison-of-bleeding-risk-scores-in-patients-with-atrial-fibrillation-insights-from-the-re-ly-trial
#18
M Proietti, Z Hijazi, U Andersson, S J Connolly, J W Eikelboom, M D Ezekowitz, D A Lane, J Oldgren, V Roldan, S Yusuf, L Wallentin
BACKGROUND: Oral anticoagulation is the mainstay of stroke prevention in atrial fibrillation (AF), but must be balanced against the associated bleeding risk. Several risk scores have been proposed for prediction of bleeding events in patients with AF. OBJECTIVES: To compare the performance of contemporary clinical bleeding risk scores in 18 113 patients with AF randomized to dabigatran 110 mg, 150 mg or warfarin in the RE-LY trial. METHODS: HAS-BLED, ORBIT, ATRIA and HEMORR2 HAGES bleeding risk scores were calculated based on clinical information at baseline...
October 16, 2017: Journal of Internal Medicine
https://www.readbyqxmd.com/read/29036603/identification-of-optimal-reference-genes-for-transcriptomic-analyses-in-normal-and-diseased-human-heart
#19
Cristina E Molina, Eric Jacquet, Prishila Ponien, Christian Muñoz-Guijosa, Istvan Baczkó, Lars S Maier, Patrick Donzeau-Gouge, Dobromir Dobrev, Rodolphe Fischmeister, Anne Garnier
Aims: Quantitative real-time RT-PCR (RT-qPCR) has become the method of choice for mRNA quantification, but requires an accurate normalization based on the use of reference genes showing invariant expression across various pathological conditions. Only few data exist on appropriate reference genes for the human heart. The objective of this study was to determine a set of suitable reference genes in human atrial and ventricular tissues, from right and left cavities in control and in cardiac diseases...
September 22, 2017: Cardiovascular Research
https://www.readbyqxmd.com/read/29030869/evaluation-of-the-predictive-performance-of-bleeding-risk-scores-in-patients-with-non-valvular-atrial-fibrillation-on-oral-anticoagulants
#20
S A Beshir, Z Aziz, L B Yap, K H Chee, Y L Lo
WHAT IS KNOWN AND OBJECTIVE: Bleeding risk scores (BRSs) aid in the assessment of oral anticoagulant-related bleeding risk in patients with atrial fibrillation. Ideally, the applicability of a BRS needs to be assessed, prior to its routine use in a population other than the original derivation cohort. Therefore, we evaluated the performance of 6 established BRSs to predict major or clinically relevant bleeding (CRB) events associated with the use of oral anticoagulant (OAC) among Malaysian patients...
October 13, 2017: Journal of Clinical Pharmacy and Therapeutics
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