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https://www.readbyqxmd.com/read/27905214/the-association-of-plasma-oxidative-status-and-inflammation-with-the-development-of-atrial-fibrillation-in-patients-presenting-with-st-elevation-myocardial-infarction
#1
Hasan Aydin Bas, Fatih Aksoy, Atilla Icli, Ercan Varol, Abdullah Dogan, Dogan Erdogan, Ibrahim Ersoy, Akif Arslan, Hatem Ari, Nihal Bas, Recep Sutcu, Mehmet Ozaydin
Atrial fibrillation (AF) is the most common supraventricular arrhythmia following ST elevation myocardial infarction (STEMI). Oxidative stress and inflammation may cause structural and electrical remodeling in the atria making these critical processes in the pathology of AF. In this study, we aimed to evaluate the association between total oxidative status (TOS), total antioxidative capacity (TAC) and high-sensitivity C-reactive protein (hs-CRP) in the development of AF in patients presenting with STEMI. This prospective cohort study consisted of 346 patients with STEMI...
December 1, 2016: Scandinavian Journal of Clinical and Laboratory Investigation
https://www.readbyqxmd.com/read/27884747/novel-function-of-%C3%AE-1d-l-type-calcium-channel-in-the-atria
#2
Ujala Srivastava, Ademuyiwa S Aromolaran, Frank Fabris, Deana Lazaro, John Kassotis, Yongxia Qu, Mohamed Boutjdir
Ca entry through atrial L-type Calcium channels (α1C and α1D) play an important role in muscular contraction, regulation of gene expression, and release of hormones including atrial natriuretic peptide (ANP), and brain natriuretic peptide (BNP). α1D Ca channel is exclusively expressed in atria, and has been shown to play a key role in the pathogenesis of atrial fibrillation. Recent data have shown that the small conductance calcium-activated potassium channel, SK4 is also atrial specific and also contributes prominently to the secretion of ANP and BNP...
November 22, 2016: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/27882143/expression-of-connexin-43-ion-channels-and-ca-2-handling-proteins-in-rat-pulmonary-vein-cardiomyocytes
#3
Yaqiong Xiao, Xue Cai, Andrew Atkinson, Sunil Jit Logantha, Mark Boyett, Halina Dobrzynski
Atrial fibrillation (AF) is the most common cardiac arrhythmia. AF is thought to be triggered by ectopic beats, originating primarily in the myocardial sleeves surrounding the pulmonary veins (PVs). The mechanisms underlying these cardiac arrhythmias remain unclear. To investigate this, frozen sections of heart and lung tissue from adult rats without arrhythmia were obtained in different planes, stained with Masson's trichrome, and immunolabeled for connexin 43 (Cx43), caveolin-3 (Cav3), hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4), Nav1...
November 2016: Experimental and Therapeutic Medicine
https://www.readbyqxmd.com/read/27878421/the-role-of-the-atrial-electromechanical-delay-in-predicting-atrial-fibrillation-in-beta-thalassemia-major-patients
#4
Anna Rago, Vincenzo Russo, Andrea Antonio Papa, Carmine Ciardiello, Bruno Pannone, Maria Carolina Mayer, Giovanni Cimmino, Gerardo Nigro
BACKGROUND: Paroxysmal atrial tachyarrhythmias frequently occur in beta-thalassemia major (β-TM) patients. The aim of the current study was to evaluate the atrial electromechanical delay (AEMD) in a large β-TM population with normal cardiac function and its relationship to atrial fibrillation (AF) onset. METHODS: Eighty β-TM patients (44 men, 36 women), with a mean age of 36.2 ± 11.1 years, and 80 healthy subjects used as controls, matched for age and gender, were studied for the occurrence of AF during a 5-year follow-up, through 30-day external loop recorder (ELR) monitoring performed every 6 months...
November 22, 2016: Journal of Interventional Cardiac Electrophysiology: An International Journal of Arrhythmias and Pacing
https://www.readbyqxmd.com/read/27863381/probucol-prevents-atrial-ion-channel-remodeling-in-an-alloxan-induced-diabetes-rabbit-model
#5
Huaying Fu, Guangping Li, Changle Liu, Jian Li, Lijun Cheng, Wansong Yang, Gary Tse, Jichao Zhao, Tong Liu
Diabetes mellitus (DM) increases the risk of developing atrial fibrillation (AF), but the molecular mechanisms of diabetes-induced atrial remodeling processes have not been fully characterized. The aim of this study was to examine the mechanisms underlying atrial ion channel remodeling in alloxan-induced diabetes model in rabbits. A total of 40 Japanese rabbits were randomly assigned to a control group (C), alloxan-induced diabetic group (DM), probucol-treated control group (Control-P), and probucol-treated diabetic group (DM-P)...
November 14, 2016: Oncotarget
https://www.readbyqxmd.com/read/27826248/slow-conduction-in-the-border-zones-of-patchy-fibrosis-stabilizes-the-drivers-for-atrial-fibrillation-insights-from-multi-scale-human-atrial-modeling
#6
Ross Morgan, Michael A Colman, Henry Chubb, Gunnar Seemann, Oleg V Aslanidi
Introduction: The genesis of atrial fibrillation (AF) and success of AF ablation therapy have been strongly linked with atrial fibrosis. Increasing evidence suggests that patient-specific distributions of fibrosis may determine the locations of electrical drivers (rotors) sustaining AF, but the underlying mechanisms are incompletely understood. This study aims to elucidate a missing mechanistic link between patient-specific fibrosis distributions and AF drivers. Methods: 3D atrial models integrated human atrial geometry, rule-based fiber orientation, region-specific electrophysiology, and AF-induced ionic remodeling...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27823686/how-well-does-physician-risk-assessment-predict-stroke-and-bleeding-in-atrial-fibrillation-results-from-the-outcomes-registry-for-better-informed-treatment-of-atrial-fibrillation-orbit-af
#7
Benjamin A Steinberg, Peter Shrader, Sunghee Kim, Laine Thomas, Gregg C Fonarow, Jack Ansell, Peter R Kowey, Daniel E Singer, Bernard J Gersh, Kenneth W Mahaffey, Eric D Peterson, Jonathan P Piccini
BACKGROUND: Assessments of stroke and bleeding risks are essential to selecting oral anticoagulation in patients with atrial fibrillation (AF). We aimed to assess outcomes according to physician assessed risk, with comparison to empirical risk scores. METHODS: This was a prospective, observational study of 9,715 outpatients with AF enrolled in ORBIT-AF, a US national registry. Stroke and bleeding risks were quantified by physician assignment, CHADS2 and CHA2DS2-VASc stroke scores, and ATRIA and HAS-BLED bleeding scores...
November 2016: American Heart Journal
https://www.readbyqxmd.com/read/27812021/mechanisms-of-arrhythmogenesis-related-to-calcium-driven-alternans-in-a-model-of-human-atrial-fibrillation
#8
Kelly C Chang, Natalia A Trayanova
The occurrence of atrial fibrillation (AF) is associated with progressive changes in the calcium handling system of atrial myocytes. Calcium cycling instability has been implicated as an underlying mechanism of electrical alternans observed in patients who experience AF. However, the extent to which calcium-induced alternation of electrical activity in the atria contributes to arrhythmogenesis is unknown. In this study, we investigated the effects of calcium-driven alternans (CDA) on arrhythmia susceptibility in a biophysically detailed, 3D computer model of the human atria representing electrical and structural remodeling secondary to chronic AF...
November 4, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27790158/regularization-techniques-for-ecg-imaging-during-atrial-fibrillation-a-computational-study
#9
Carlos Figuera, Víctor Suárez-Gutiérrez, Ismael Hernández-Romero, Miguel Rodrigo, Alejandro Liberos, Felipe Atienza, María S Guillem, Óscar Barquero-Pérez, Andreu M Climent, Felipe Alonso-Atienza
The inverse problem of electrocardiography is usually analyzed during stationary rhythms. However, the performance of the regularization methods under fibrillatory conditions has not been fully studied. In this work, we assessed different regularization techniques during atrial fibrillation (AF) for estimating four target parameters, namely, epicardial potentials, dominant frequency (DF), phase maps, and singularity point (SP) location. We use a realistic mathematical model of atria and torso anatomy with three different electrical activity patterns (i...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27773652/refractoriness-in-human-atria-time-and-voltage-dependence-of-sodium-channel-availability
#10
Lasse Skibsbye, Thomas Jespersen, Torsten Christ, Mary M Maleckar, Jonas van den Brink, Pasi Tavi, Jussi T Koivumäki
BACKGROUND: Refractoriness of cardiac cells limits maximum frequency of electrical activity and protects the heart from tonic contractions. Short refractory periods support major arrhythmogenic substrates and augmentation of refractoriness is therefore seen as a main mechanism of antiarrhythmic drugs. Cardiomyocyte excitability depends on availability of sodium channels, which involves both time- and voltage-dependent recovery from inactivation. This study therefore aims to characterise how sodium channel inactivation affects refractoriness in human atria...
October 20, 2016: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/27765191/pitx2-modulates-atrial-membrane-potential-and-the-antiarrhythmic-effects%C3%A2-of%C3%A2-sodium-channel-blockers
#11
Fahima Syeda, Andrew P Holmes, Ting Y Yu, Samantha Tull, Stefan Michael Kuhlmann, Davor Pavlovic, Daniel Betney, Genna Riley, Jan P Kucera, Florian Jousset, Joris R de Groot, Stephan Rohr, Nigel A Brown, Larissa Fabritz, Paulus Kirchhof
BACKGROUND: Antiarrhythmic drugs are widely used to treat patients with atrial fibrillation (AF), but the mechanisms conveying their variable effectiveness are not known. Recent data suggested that paired like homeodomain-2 transcription factor (PITX2) might play an important role in regulating gene expression and electrical function of the adult left atrium (LA). OBJECTIVES: After determining LA PITX2 expression in AF patients requiring rhythm control therapy, the authors assessed the effects of Pitx2c on LA electrophysiology and the effect of antiarrhythmic drugs...
October 25, 2016: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/27742566/atrial-fibrillation-therapeutic-potential-of-atrial-k-channel-blockers
#12
Ursula Ravens, Katja E Odening
Despite the epidemiological scale of atrial fibrillation, current treatment strategies are of limited efficacy and safety. Ideally, novel drugs should specifically correct the pathophysiological mechanisms responsible for atrial fibrillation with no other cardiac or extracardiac actions. Atrial-selective drugs are directed toward cellular targets with sufficiently different characteristics in atria and ventricles to modify only atrial function. Several potassium (K(+)) channels with either predominant expression in atria or distinct electrophysiological properties in atria and ventricles can serve as atrial-selective drug targets...
October 12, 2016: Pharmacology & Therapeutics
https://www.readbyqxmd.com/read/27699086/atrial-fibrillation-the-science-behind-its-defiance
#13
Maureen E Czick, Christine L Shapter, David I Silverman
Atrial fibrillation (AF) is the most prevalent arrhythmia in the world, due both to its tenacious treatment resistance, and to the tremendous number of risk factors that set the stage for the atria to fibrillate. Cardiopulmonary, behavioral, and psychological risk factors generate electrical and structural alterations of the atria that promote reentry and wavebreak. These culminate in fibrillation once atrial ectopic beats set the arrhythmia process in motion. There is growing evidence that chronic stress can physically alter the emotion centers of the limbic system, changing their input to the hypothalamic-limbic-autonomic network that regulates autonomic outflow...
October 2016: Aging and Disease
https://www.readbyqxmd.com/read/27670628/regional-distribution-of-t-tubule-density-in-left-and-right-atria-in-dogs
#14
Rishi Arora, Gary L Aistrup, Stephen Supple, Caleb Frank, Jasleen Singh, Shannon Tai, Anne Zhao, Laura Chicos, William Marszalec, Ang Guo, Long-Sheng Song, J Andrew Wasserstrom
BACKGROUND: The peculiarities of transverse tubule (T-tubule) morphology and distribution in the atrium-and how they contribute to excitation-contraction coupling-are just beginning to be understood. OBJECTIVES: The objectives of this study were to determine T-tubule density in the intact, live right and left atria in a large animal and to determine intraregional differences in T-tubule organization within each atrium. METHODS: Using confocal microscopy, T-tubules were imaged in both atria in intact, Langendorf-perfused normal dog hearts loaded with di-4-ANEPPS...
September 23, 2016: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/27660282/cross-talk-between-macrophages-and-atrial-myocytes-in-atrial-fibrillation
#15
Zewei Sun, Dongchen Zhou, Xudong Xie, Shuai Wang, Zhen Wang, Wenting Zhao, Hongfei Xu, Liangrong Zheng
Increased macrophage accumulation occurs in the atria of patients with atrial fibrillation (AF). However, the phenotype and functions of the macrophages in AF remain unclear. We investigated the macrophage-atrial myocyte interaction in AF patients and found that the increased macrophages were mainly pro-inflammatory macrophages (iNOS(+), Arg1(-)). Tachypacing of HL-1 atrial myocytes also led to pro-inflammatory macrophage polarization. In addition, lipopolysaccharide (LPS)-stimulated pro-inflammatory macrophages-induced atrial electrical remodeling, evidenced by increased AF incidence and decreased atrial effective refractory period and L-type calcium currents (I Ca-L) in both canine and mouse AF models...
November 2016: Basic Research in Cardiology
https://www.readbyqxmd.com/read/27650831/the-troms%C3%A3-study-1974-2016-forty-years-of-cardiovascular-research
#16
Inger Njølstad, Ellisiv B Mathiesen, Henrik Schirmer, Dag Steinar Thelle
The rapid increase of coronary heart disease mortality in Northern Norway during 1951-1970 was why the newly established University of Tromsø decided to start a study to identify major operating cardiovascular risk factors. The first Tromsø survey in 1974 suggested that the relatively high cardiovascular mortality was associated with elevated cholesterol levels and high prevalence of smoking, while high-density-lipoprotein-cholesterol (HDL-C) was identified as a preventive factor. After 1974, six more surveys including both genders (aged 20 to 89 years) were undertaken...
September 21, 2016: Scandinavian Cardiovascular Journal: SCJ
https://www.readbyqxmd.com/read/27643943/ageing-related-down-regulation-of-myocardial-connexin-43-and-up-regulation-of-mmp-2-may-predict-propensity-to-atrial-fibrillation-in-experimental-animals
#17
V Nagibin, T Egan Benova, C Viczenczova, B Szeiffova Bacova, I Dovinova, M Barancik, N Tribulova
Mechanisms underlying atrial fibrillation (AF), the most common cardiac arrhythmia, particularly in aged population, are not fully elucidated. We have previously shown an increased propensity of old guinea pigs (GPs) heart to inducible AF when comparing to young animals. This study aimed to verify our hypothesis that susceptibility of aged heart to AF may be attributed to abnormalities in myocardial connexin-43 (Cx43) and extracellular matrix that affect cardiac electrical properties. Experiments were conducted on male and female 4-week-old and 24-week-old GPs...
September 19, 2016: Physiological Research
https://www.readbyqxmd.com/read/27643440/atrial-specific-pathways-for-control-of-intracellular-signaling-and-myocyte-function
#18
Thomas J Hund, Peter J Mohler
Atrial fibrillation (AF) is a cardiac arrhythmia that arises from electrical and contractile dysfunction in the atria. Atrial function is regulated by a variety of intracellular signaling networks that facilitate rapid communication and coordinate responses of atrial myocytes. In this issue of the JCI, Brandenburg and colleagues describe the identification and characterization of "super-hub" signaling nodes located on atrial axial tubules that regulate atrial contraction. Together, the results of this study provide important insight into the regulation of atrial contraction and describe potential therapeutic targets to be explored in future studies...
October 3, 2016: Journal of Clinical Investigation
https://www.readbyqxmd.com/read/27630135/lone-atrial-fibrillation-is-associated-with-impaired-left-ventricular-energetics-that-persists-despite-successful-catheter-ablation
#19
Rohan S Wijesurendra, Alexander Liu, Christian Eichhorn, Rina Ariga, Eylem Levelt, William T Clarke, Christopher T Rodgers, Theodoros D Karamitsos, Yaver Bashir, Matthew Ginks, Kim Rajappan, Tim Betts, Vanessa M Ferreira, Stefan Neubauer, Barbara Casadei
BACKGROUND: Lone atrial fibrillation (AF) may reflect a subclinical cardiomyopathy that persists after sinus rhythm (SR) restoration, providing a substrate for AF recurrence. To test this hypothesis, we investigated the effect of restoring SR by catheter ablation on left ventricular (LV) function and energetics in patients with AF but no significant comorbidities. METHODS: Fifty-three patients with symptomatic paroxysmal or persistent AF and without significant valvular disease, uncontrolled hypertension, coronary artery disease, uncontrolled thyroid disease, systemic inflammatory disease, diabetes mellitus, or obstructive sleep apnea (ie, lone AF) undergoing ablation and 25 matched control subjects in SR were investigated...
October 11, 2016: Circulation
https://www.readbyqxmd.com/read/27609676/ganglion-plexus-ablation-in-advanced%C3%A2-atrial-fibrillation-the-afact-study
#20
Antoine H G Driessen, Wouter R Berger, Sébastien P J Krul, Nicoline W E van den Berg, Jolien Neefs, Femke R Piersma, Dean R P P Chan Pin Yin, Jonas S S G de Jong, WimJan P van Boven, Joris R de Groot
BACKGROUND: Patients with long duration of atrial fibrillation (AF), enlarged atria, or failed catheter ablation have advanced AF and may require more extensive treatment than pulmonary vein isolation. OBJECTIVES: The aim of this study was to investigate the efficacy and safety of additional ganglion plexus (GP) ablation in patients undergoing thoracoscopic AF surgery. METHODS: Patients with paroxysmal AF underwent pulmonary vein isolation...
September 13, 2016: Journal of the American College of Cardiology
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