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https://www.readbyqxmd.com/read/28207381/personalized-models-of-human-atrial-electrophysiology-derived-from-endocardial-electrograms
#1
Cesare Corrado, John Whitaker, Henry Chubb, Steven Williams, Matthew Wright, Jaswinder Gill, Mark O'Neill, Steven Niederer
OBJECTIVE: Computational models represent a novel framework for understanding the mechanisms behind atrial fibrillation (AF) and offer a pathway for personalizing and optimizing treatment. The characterization of local electrophysiological properties across the atria during procedures remains a challenge. The aim of this work is to characterize the regional properties of the human atrium from multi-electrode catheter measurements. METHODS: We propose a novel method that characterizes regional electrophysiology properties by fitting parameters of an ionic model to conduction velocity and effective refractory period restitution curves obtained by a s1 s2 pacing protocol applied through a multi-electrode catheter...
May 30, 2016: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28205526/association-evidence-of-ccttt-repeat-polymorphism-in-the-inos-promoter-and-the-risk-of-atrial-fibrillation-in-taiwanese
#2
Lung-An Hsu, Yung-Hsin Yeh, Wei-Jan Chen, Chi-Tai Kuo, Feng-Chun Tsai, Yi-Hsin Chan, Chun-Li Wang, Chi-Jen Chang, Hsin-Yi Tsai
Inducible nitric oxide synthase (iNOS) plays an important role in the pathogenesis of atrial fibrillation (AF). The iNOS promoter has a CCTTT-repeat length polymorphism that can determine the level of gene transcription. This study enrolled 200 AF patients and 240 controls. The length of CCTTT-repeat polymorphism in the iNOS promoter region was examined by polymerase chain reactions, with the alleles with ≤11 repeats designated as S and alleles with ≥12 repeats designated as L alleles. AF patients carried significantly higher frequencies of the LL genotype than control subjects (40...
February 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28192083/anatomical-and-spiral-wave-reentry-in-a-simplified-model-for-atrial-electrophysiology
#3
Yvonne Richter, Pedro G Lind, Gunnar Seemann, Philipp Maass
For modeling the propagation of action potentials in the human atria, various models have been developed in the past, which take into account in detail the influence of the numerous ionic currents flowing through the cell membrane. Aiming at a simplified description, the Bueno-Orovio-Cherry-Fenton (BOCF) model for electric wave propagation in the ventricle has been adapted recently to atrial physiology. Here, we study this adapted BOCF (aBOCF) model with respect to its capability to accurately generate spatio-temporal excitation patterns found in anatomical and spiral wave reentry...
February 10, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28181684/exercise-based-cardiac-rehabilitation-for-adults-with-atrial-fibrillation
#4
REVIEW
Signe S Risom, Ann-Dorthe Zwisler, Pernille P Johansen, Kirstine L Sibilitz, Jane Lindschou, Christian Gluud, Rod S Taylor, Jesper H Svendsen, Selina K Berg
BACKGROUND: Exercise-based cardiac rehabilitation may benefit adults with atrial fibrillation or those who had been treated for atrial fibrillation. Atrial fibrillation is caused by multiple micro re-entry circuits within the atrial tissue, which result in chaotic rapid activity in the atria. OBJECTIVES: To assess the benefits and harms of exercise-based rehabilitation programmes, alone or with another intervention, compared with no-exercise training controls in adults who currently have AF, or have been treated for AF...
February 9, 2017: Cochrane Database of Systematic Reviews
https://www.readbyqxmd.com/read/28178995/reference-ranges-for-cardiac-structure-and-function-using-cardiovascular-magnetic-resonance-cmr-in-caucasians-from-the-uk-biobank-population-cohort
#5
Steffen E Petersen, Nay Aung, Mihir M Sanghvi, Filip Zemrak, Kenneth Fung, Jose Miguel Paiva, Jane M Francis, Mohammed Y Khanji, Elena Lukaschuk, Aaron M Lee, Valentina Carapella, Young Jin Kim, Paul Leeson, Stefan K Piechnik, Stefan Neubauer
BACKGROUND: Cardiovascular magnetic resonance (CMR) is the gold standard method for the assessment of cardiac structure and function. Reference ranges permit differentiation between normal and pathological states. To date, this study is the largest to provide CMR specific reference ranges for left ventricular, right ventricular, left atrial and right atrial structure and function derived from truly healthy Caucasian adults aged 45-74. METHODS: Five thousand sixty-five UK Biobank participants underwent CMR using steady-state free precession imaging at 1...
February 3, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28172967/use-of-delayed-enhancement-magnetic-resonance-imaging-for-fibrosis-detection-in-the-atria-a-review
#6
Giulia Pontecorboli, Rosa M Figueras I Ventura, Alicia Carlosena, Eva Benito, Susanna Prat-Gonzales, Luigi Padeletti, Lluís Mont
No abstract text is available yet for this article.
February 1, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28162963/assessment-of-the-atrial-electromechanical-properties-of-patients-with-human-immunodeficiency-virus
#7
Ahmet G Ertem, Çağrı Yayla, Burak Açar, Sefa Ünal, Mehmet A Erdol, Meliha Ç Sonmezer, Esra Kaya Kiliç, Çiğdem Ataman Hatipoglu, Serkan Gokaslan, Habibe Kafes, Mehmet K Akboga, Pelin Aladag, Koray Demirtas, Sinan Aydogdu
The relationship between atrial fibrillation and human immunodeficiency virus (HIV) infection was evaluated. Electro-echocardiographic methods can be used to predict the development of atrial fibrillation (AF). In this study, we aimed to investigate the atrial electromechanical delay (AEMD) parameters of HIV (+) patients. Forty-two HIV (+) patients and 40 HIV (-) healthy volunteers were prospectively enrolled in this study. The electromechanical properties of the subjects' atria were evaluated with tissue Doppler imaging...
February 2, 2017: Journal of Infection and Public Health
https://www.readbyqxmd.com/read/28159543/equivalent-dipole-sources-to-estimate-the-influence-of-extracellular-myocardial-anisotropy-in-thin-walled-cardiac-forward-models
#8
Vincent Jacquemet
The extracellular domain of the heart is anisotropic, which affects volume conduction and therefore body surface potentials. This paper tests the hypothesis that when wall thickness is sufficiently small (such as in the atria), the effect of extracellular anisotropy can be estimated by modifying local dipole current sources. A formula based on the Gabor-Nelson equivalent dipole and on the reciprocity theorem is derived to compute a linear transformation of the dipole sources that approximates in an isotropic volume conductor the far-field of the actual sources in an anisotropic volume conductor...
January 31, 2017: Mathematical Biosciences
https://www.readbyqxmd.com/read/28155995/sinus-node-dysfunction-and-atrial-fibrillation-a-reversible-phenomenon
#9
REVIEW
Larry R Jackson Ii, Bharath Rathakrishnan, Kristen Campbell, Kevin L Thomas, Jonathan P Piccini, Tristram Bahnson, Jonathan A Stiber, James P Daubert
BACKGROUND: Symptomatic sinus node dysfunction (SND) consists of a variety of manifestations including tachycardia-bradycardia syndrome. Atrial fibrillation (AF) is commonly associated with SND, which complicates the management of both conditions. This paper reviews the epidemiology, pathophysiology, and clinical trial data investigating therapeutic approaches for treatment of patients with both SND and AF. METHODS: The authors reviewed articles published in English describing the epidemiology, pathophysiology, and therapeutic approaches for patients with SND and AF...
February 3, 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/28143616/hypertrophic-obstructive-cardiomyopathy-with-multiple-coronary-arteries-to-right-ventricular-microfistulas-a-case-report-and-review-of-the-literature
#10
Daulat Singh Meena, Chandra Bhan Meena, Javed Parvez
BACKGROUND: Coronary artery microfistulas are a rare anomaly; their association with hypertrophic cardiomyopathy is even rarer and can lead to serious cardiac complications owing to coronary steal phenomena such as angina pectoris, myocardial infarction, congestive heart failure, ventricular and supraventricular arrhythmias, syncope, and sudden death. CASE PRESENTATION: A 32-year-old Indian woman presented to our institute with severe angina on exertion and multiple episodes of pre-syncope...
January 31, 2017: Journal of Medical Case Reports
https://www.readbyqxmd.com/read/28140773/the-kaleidoscopic-nature-of-griefa-review-of-grief-is-a-journey-finding-your-path-through-loss-by-kenneth-j-doka-new-york-ny-atria-books-2016-304-pp-isbn-978-1476771480-26-00
#11
https://www.readbyqxmd.com/read/28133984/new-arylsparteine-derivatives-as-positive-inotropic-drugs
#12
Vito Boido, Marcella Ercoli, Michele Tonelli, Federica Novelli, Bruno Tasso, Fabio Sparatore, Elena Cichero, Paola Fossa, Paola Dorigo, Guglielmina Froldi
Positive inotropic agents are fundamental in the treatment of heart failure; however, their arrhythmogenic liability and the increased myocardial oxygen demand strongly limit their therapeutic utility. Pursuing our study on cardiovascular activities of lupin alkaloid derivatives, several 2-(4-substituted-phenyl)-2-dehydrosparteines and 2-(4-substituted-phenyl)sparteines were prepared and tested for inotropic and chronotropic activities on isolated guinea pig atria. Four compounds (6b, 6e, 7b, and 7f) exhibited significant inotropism that, at the higher concentrations, was followed by negative inotropism or toxicity...
December 2017: Journal of Enzyme Inhibition and Medicinal Chemistry
https://www.readbyqxmd.com/read/28129887/a-left-lateral-accessory-pathway-unmasked-by-rivastigmine
#13
Charles Guenancia, Marie Fichot, Fabien Garnier, Mathieu Montoy, Gabriel Laurent
A 75-year-old woman was referred for advice regarding surface electrocardiographic modifications after the initiation of rivastigmine. In our patient, the baseline ECGs appeared perfectly normal. However, the initiation of a cholinesterase inhibitor unmasked a left lateral accessory pathway that had never been diagnosed before. Although cholinesterase inhibitors are known to increase vagal tone, the PR interval was shortened after rivastigmine administration, thus excluding this hypothesis to explain the appearance of the accessory pathway...
January 16, 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/28128201/disruption-of-cardiac-cholinergic-neurons-enhances-susceptibility-to-ventricular-arrhythmias
#14
Christiane Jungen, Katharina Scherschel, Christian Eickholt, Pawel Kuklik, Niklas Klatt, Nadja Bork, Tim Salzbrunn, Fares Alken, Stephan Angendohr, Christiane Klene, Janos Mester, Nikolaj Klöcker, Marieke W Veldkamp, Udo Schumacher, Stephan Willems, Viacheslav O Nikolaev, Christian Meyer
The parasympathetic nervous system plays an important role in the pathophysiology of atrial fibrillation. Catheter ablation, a minimally invasive procedure deactivating abnormal firing cardiac tissue, is increasingly becoming the therapy of choice for atrial fibrillation. This is inevitably associated with the obliteration of cardiac cholinergic neurons. However, the impact on ventricular electrophysiology is unclear. Here we show that cardiac cholinergic neurons modulate ventricular electrophysiology. Mechanical disruption or pharmacological blockade of parasympathetic innervation shortens ventricular refractory periods, increases the incidence of ventricular arrhythmia and decreases ventricular cAMP levels in murine hearts...
January 27, 2017: Nature Communications
https://www.readbyqxmd.com/read/28124622/intermittent-hypoxia-causes-nox2-dependent-remodeling-of-atrial-connexins
#15
Joanna Gemel, Zihan Su, Alex Gileles-Hillel, Abdelnaby Khalyfa, David Gozal, Eric C Beyer
BACKGROUND: Obstructive sleep apnea has been linked to the development of heart disease and arrhythmias, including atrial fibrillation. Since altered conduction through gap junction channels can contribute to the pathogenesis of such arrhythmias, we examined the abundance and distributions of the major cardiac gap junction proteins, connexin40 (Cx40) and connexin43 (Cx43) in mice treated with sleep fragmentation or intermittent hypoxia (IH) as animal models of the components of obstructive sleep apnea...
January 17, 2017: BMC Cell Biology
https://www.readbyqxmd.com/read/28123766/low-incidence-of-left-atrial-delayed-enhancement-with-mri-in-patients-with-af-a-single-centre-experience
#16
John P Bois, James Glockner, Phillip M Young, Thomas A Foley, Seth Sheldon, Darrell B Newman, Grace Lin, Douglas L Packer, Peter A Brady
BACKGROUND: Atrial fibrillation (AF) is the most common sustained atrial arrhythmia. One potential target for ablation is left atrial (LA) scar (LAS) regions that may be the substrate for re-entry within the atria, thereby sustaining AF. Identification of LAS through LA delayed gadolinium enhancement (LADE) with MRI has been proposed. OBJECTIVES: We sought to evaluate LADE in patients referred for catheter ablation of AF. METHODS: Prospective analysis was conducted of consecutive patients who underwent pulmonary vein antrum isolation (PVAI) ablation for AF at a single institution...
2017: Open Heart
https://www.readbyqxmd.com/read/28115807/functional-remodeling-of-both-atria-is-associated-with-occurrence-of-stroke-in-patients-with-paroxysmal-and-persistent-atrial-fibrillation
#17
Hsuan-Ming Tsao, Wei-Chih Hu, Ping-Huang Tsai, Chao-Lin Lee, Hsueh-Han Wang, Shih-Lin Chang, Tze-Fan Chao, Shih-Ann Chen
BACKGROUND: It is critical to recognize high risk patients who are prone to develop stroke in the management of atrial fibrillation (AF). The purpose of this study was to identify the determinants of AF related stroke by assessing the anatomical and functional remodeling of cardiac chambers. METHODS: We compared the cardiac structure and function of 28 consecutive patients with paroxysmal and persistent AF-related stroke with 69 patients with AF and 21 controls without stroke using contrast-enhanced 64-slice multi-detector computed tomography during sinus rhythm...
January 2017: Acta Cardiologica Sinica
https://www.readbyqxmd.com/read/28106018/cardioneuroablation-in-the-treatment-of-neurally-mediated-reflex-syncope-a-review-of-the-current-literature
#18
Tolga Aksu, Tümer Erdem Güler, Serdar Bozyel, Kazım Serhan Özcan, Kıvanç Yalın, Ferit Onur Mutluer
OBJECTIVE: An imbalance between parasympathetic and sympathetic tone is a main cause of neurally mediated reflex syncope (NMRS). These patients may be very symptomatic and the condition may require cardiac pacemaker implantation. Cardioneuroablation (CNA) is a relatively novel technique based on radiofrequency ablation of vagal ganglia that can be used in treatment of NMRS. The aim of this analysis was to compare potential role of CNA in patients with NMRS. METHODS: In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement, literature search was conducted using the keywords "cardioneuroablation," "vagal denervation," "reflex syncope," "vagal ablation," and "ganglionic plexi ablation...
December 2017: Türk Kardiyoloji Derneği Arşivi: Türk Kardiyoloji Derneğinin Yayın Organıdır
https://www.readbyqxmd.com/read/28104073/af-ablation-guided-by-spatiotemporal-electrogram-dispersion%C3%A2-without-pulmonary-vein-isolation-a-wholly-patient-tailored-approach
#19
Julien Seitz, Clément Bars, Guillaume Théodore, Sylvain Beurtheret, Nicolas Lellouche, Michel Bremondy, Ange Ferracci, Jacques Faure, Guillaume Penaranda, Masatoshi Yamazaki, Uma Mahesh R Avula, Laurence Curel, Sabrina Siame, Omer Berenfeld, André Pisapia, Jérôme Kalifa
BACKGROUND: The use of intracardiac electrograms to guide atrial fibrillation (AF) ablation has yielded conflicting results. OBJECTIVES: The authors evaluated the usefulness of spatiotemporal dispersion, a visually recognizable electric footprint of AF drivers, for the ablation of all forms of AF. METHODS: The authors prospectively enrolled 105 patients admitted for AF ablation. AF was sequentially mapped in both atria with a 20-pole PentaRay catheter...
January 24, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/28100216/antispasmodic-bronchodilator-vasorelaxant-and-cardiosuppressant-effects-of-buxus-papillosa
#20
Arif-Ullah Khan, Shamsher Ali, Anwarul-Hassan Gilani, Manzoor Ahmed, Muhammad Iqbal Choudhary
BACKGROUND: The present research was carried out to investigate pharmacological properties of Buxus papillosa C.K. Schneid. (Buxaceae). METHODS: Buxus papillosa extracts of leaves (BpL), stem (BpS), roots (BpR) and BpL fractions: hexane (BpL-H), aqueous (BpL-A) also plant constituent, cyclomicrobuxine effect were studied in jejunum, atria, aorta and tracheal preparations from rabbit and guine-peg. RESULTS: Ca(++) antagonistic effect of BpS, BpR, BpL-H, BpL-A and cyclomicrobuxine were conclusively suggested, when spontaneous contractions of rabbit jejunal preparation was relaxed along with subsequent relaxation of potassium chloride (80 mM) induced contractions...
January 18, 2017: BMC Complementary and Alternative Medicine
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