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https://www.readbyqxmd.com/read/29133182/a-novel-method-for-localization-and-ablation-of-conduction-gaps-after-wide-antral-circumferential-ablation-of-pulmonary-veins
#1
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/29120873/a-rare-case-of-isolated-atrial-myocarditis-causing-death-with-no-post-mortem-computed-tomography-scan-correlation
#2
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/29032506/differential-effects-of-amp-activated-protein-kinase-in-isolated-rat-atria-subjected-to-simulated-ischemia-reperfusion-depending-on-the-energetic-substrates-available
#3
Romina Hermann, Victoria Evangelina Mestre Cordero, María de Las Mercedes Fernández Pazos, Federico Joaquín Reznik, Débora Elisabet Vélez, Enrique Alberto Savino, María Gabriela Marina Prendes, Alicia Varela
AMP-activated protein kinase (AMPK) is a serine-threonine kinase that functions primarily as a metabolic sensor to coordinate anabolic and catabolic processes in the cell, via phosphorylation of multiple proteins involved in metabolic pathways, aimed to re-establish energy homeostasis at a cell-autonomous level. Myocardial ischemia and reperfusion represents a metabolic stress situation for myocytes. Whether AMPK plays a critical role in the metabolic and functional responses involved in these conditions remains uncertain...
October 14, 2017: Pflügers Archiv: European Journal of Physiology
https://www.readbyqxmd.com/read/29027818/effects-of-nesfatin-1-on-atrial-contractility-and-thoracic-aorta-reactivity-in-male-rats
#4
Ayşe Barutcigil, Arda Tasatargil
BACKGROUND: This study aimed to examine the effects of nesfatin-1 on thoracic aorta vasoreactivity and to investigate the inotropic and chronotropic effects of nesfatin-1 on the spontaneous contractions of the isolated rat atria. METHODS: Isolated right atria and thoracic aorta were used in organ baths. The reactivity of the thoracic aorta was evaluated by potassium chloride (KCl), phenylephrine (Phe), acetylcholine (ACh), and sodium nitroprusside (SNP). The effects of nesfatin-1 on the spontaneous contractions of the rat atria were also examined...
October 13, 2017: Clinical and Experimental Hypertension: CHE
https://www.readbyqxmd.com/read/29016724/triggered-intracellular-calcium-waves-in-dog-and-human-left-atrial-myocytes-from-normal-and-failing-hearts
#5
Gary L Aistrup, Rishi Arora, Søren Grubb, Shin Yoo, Benjamin Toren, Manvinder Kumar, Aaron Kunamalla, William Marszalec, Tej Motiwala, Shannon Tai, Sean Yamakawa, Satya Yerrabolu, Francisco J Alvarado, Hector H Valdivia, Jonathan M Cordeiro, Yohannes Shiferaw, John Andrew Wasserstrom
Aims: Abnormal intracellular Ca2+ cycling contributes to triggered activity and arrhythmias in the heart. We investigated the properties and underlying mechanisms for systolic triggered Ca2+ waves in left atria from normal and failing dog hearts. Methods and results: Intracellular Ca2+ cycling was studied using confocal microscopy during rapid pacing of atrial myocytes (36 °C) isolated from normal and failing canine hearts (ventricular tachypacing model). In normal atrial myocytes (NAMs), Ca2+ waves developed during rapid pacing at rates ≥ 3...
November 1, 2017: Cardiovascular Research
https://www.readbyqxmd.com/read/28962867/ginsenoside-re-prevents-angiotensin-ii-induced-gap-junction-remodeling-by-activation-of-ppar%C3%AE-in-isolated-beating-rat-atria
#6
Bo Zhang, Xun Cui, Hong-Hua Jin, Lan Hong, Xia Liu, Xiang Li, Qing-Gao Zhang, Li-Ping Liu
AIMS: Ginsenoside Re (G-Re), a major ginsenoside in ginseng, has many beneficial pharmacological effects on negative cardiac contractility, electromechanical alternans, antiarrhythmia, angiogenic regeneration and cardiac electrophysiological function. However, effects of G-Re on gap-junction remodeling are unclear. Therefore, this study aimed to investigate the effect of G-Re on angiotensin II (Ang II)-induced downregulation of connexin-40 (CX40) and -43 (CX43) in beating rat left atria...
December 1, 2017: Life Sciences
https://www.readbyqxmd.com/read/28916638/pharmacological-and-physiological-assessment-of-serotonin-formation-and-degradation-in-isolated-preparations-from-mouse-and-human-heart
#7
Ulrich Gergs, Franziska Jung, Igor B Buchwalow, Britt Hofmann, Andreas Simm, Hendrik Treede, Joachim Neumann
Using transgenic mice (TG) that overexpress the human 5-HT4a-receptor specifically in cardiomyocytes, we wanted to know whether 5-HT can be formed and degraded in the mammalian heart and whether this can likewise lead to inotropic and chronotropic effects in this TG model. We noted that the 5-HT precursor, 5-hydroxy-tryptophan (5-HTP), can exert inotropic and chronotropic effects in cardiac preparations from TG but not from wild type (WT): similar results were found in human atrial preparations, as well as in intact TG animals using echocardiography...
September 15, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28898757/extracellular-matrix-derived-extracellular-vesicles-promote-cardiomyocyte-growth-and-electrical-activity-in-engineered-cardiac-atria
#8
Minae An, Kihwan Kwon, Junbeom Park, Dong-Ryeol Ryu, Jung-A Shin, Jihee Lee Kang, Ji Ha Choi, Eun-Mi Park, Kyung Eun Lee, Minna Woo, Minsuk Kim
Extracellular matrix (ECM) plays a critical role in the provision of the necessary microenvironment for the proper regeneration of the cardiac tissue. However, specific mechanisms that lead to ECM-mediated cardiac regeneration are not well understood. To elucidate the potential mechanisms, we investigated ultra-structures of the cardiac ECM using electron microscopy. Intriguingly, we observed large quantities of micro-vesicles from decellularized right atria. RNA and protein analyses revealed that these contained exosomal proteins and microRNAs (miRNAs), which we referred to herein as ECM-derived extracellular vesicles (ECM-EVs)...
November 2017: Biomaterials
https://www.readbyqxmd.com/read/28868120/novel-cilostamide-analogs-phosphodiesterase-3-inhibitors-produce-positive-inotropic-but-differential-lusitropic-and-chronotropic-effects-on-isolated-rat-atria
#9
Azar Hosseini, Reza Shafiee-Nick, Hamid Sadeghian, Heydar Parsaee
OBJECTIVES: Recently, we showed that some new synthetic compounds structurally related to cilostamide (4-(1,2-dihydro-2-oxoquinolin-6-hydroxy)- N-cyclohexyl-N-methylbutanamide), a selective phosphodiesterase 3 (PDE3) inhibitor, produce inotropic effect comparable to that of IBMX (3-isobutyl-1-methylxanthine), a non-selective PDE inhibitor, but with differential chronotropic effect. In this investigation, we compared the pharmacological effects of these compounds as potential cardiotonic agents using the spontaneously beating atria model...
June 2017: Iranian Journal of Basic Medical Sciences
https://www.readbyqxmd.com/read/28790104/first-in-man-analysis-of-the-relationship-between-electrical-rotors-from-noninvasive-panoramic-mapping-and-atrial-fibrosis-from-magnetic-resonance-imaging-in-patients-with-persistent-atrial-fibrillation
#10
Christian Sohns, Christine Lemes, Andreas Metzner, Thomas Fink, Mikhail Chmelevsky, Tilman Maurer, Margarita Budanova, Vladislav Solntsev, Walther H W Schulze, Wieland Staab, Shibu Mathew, Christian Heeger, Bruno Reißmann, Eugene Kholmovski, Dietmar Kivelitz, Feifan Ouyang, Karl-Heinz Kuck
BACKGROUND: Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging can be used to evaluate characteristics of atrial fibrosis. The novel noninvasive epicardial and endocardial electrophysiology system (NEEES) allows for the identification of sources with rotor activity. This study describes a new technique to examine the relationship between rotors and LGE signal intensity in patients with persistent atrial fibrillation (PERS) scheduled for ablation. METHODS AND RESULTS: Ten consecutive patients underwent pulmonary vein isolation for persistent atrial fibrillation...
August 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/28689254/desensitization-of-the-human-5-ht4-receptor-in-isolated-atria-of-transgenic-mice
#11
Ulrich Gergs, Julia Fritsche, Stephanie Fabian, Josepha Christ, Joachim Neumann
In the human cardiovascular system, serotonin (5-HT) exerts positive inotropic and chronotropic effects mediated by 5-HT4 receptors. Moreover, 5-HT4 receptor stimulation can cause arrhythmias in the human heart. Response to 5-HT can fade due to desensitization of the receptor system and/or activation of phosphodiesterases. In this study, we investigated a potential desensitization of the human 5-HT4(a) receptor expressed in the mouse heart. Therefore, we have used atrial preparations of transgenic (TG) mice with cardiac myocyte-specific overexpression of the human 5-HT4(a) receptor and their non-transgenic littermates (WT)...
July 8, 2017: Naunyn-Schmiedeberg's Archives of Pharmacology
https://www.readbyqxmd.com/read/28627028/common-findings-in-late-gestation-fetal-echocardiography
#12
Lauren Tague, Mary T Donofrio, Amanda Fulgium, Robert McCarter, Catherine Limperopoulos, David N Schidlow
OBJECTIVES: Fetal echocardiography provides detailed information about cardiac structure and function in utero. Limited information is available regarding normal findings late in pregnancy. We therefore sought to identify and describe common cardiac findings in late gestation. METHODS: Fetuses with structurally normal hearts were identified in mid gestation within a subset of pregnant women in a prospective study. The atrioventricular valves, right and left atria, aortic isthmus and ductus arteriosus dimensions and flow abnormalities, aneurysm of the septum primum, and presence and grade of tricuspid regurgitation were assessed throughout pregnancy...
June 19, 2017: Journal of Ultrasound in Medicine: Official Journal of the American Institute of Ultrasound in Medicine
https://www.readbyqxmd.com/read/28596994/recurrent-post-ablation-paroxysmal-atrial-fibrillation-shares-substrates-with-persistent-atrial-fibrillation-an-11-center-study
#13
Junaid A B Zaman, Tina Baykaner, Paul Clopton, Vijay Swarup, Robert C Kowal, James P Daubert, John D Day, John Hummel, Amir A Schricker, David E Krummen, Moussa Mansour, Gery F Tomassoni, Kevin R Wheelan, Mohan Vishwanathan, Shirley Park, Paul J Wang, Sanjiv M Narayan, John M Miller
INTRODUCTION: The role of atrial fibrillation (AF) substrates is unclear in patients with paroxysmal AF (PAF) that recurs after pulmonary vein isolation (PVI). We hypothesized that patients with recurrent post-ablation (redo) PAF despite PVI have electrical substrates marked by rotors and focal sources, and structural substrates that resemble persistent AF more than patients with (de novo) PAF at first ablation. METHODS: In 175 patients at 11 centers, we compared AF substrates in both atria using 64 pole-basket catheters and phase mapping, and indices of anatomical remodeling between patients with de novo or redo PAF and first ablation for persistent AF...
April 2017: JACC. Clinical Electrophysiology
https://www.readbyqxmd.com/read/28544313/neuropeptide-y-npy-inhibits-spontaneous-contraction-of-the-mouse-atrium-by-possible-activation-of-the-npy1-receptor
#14
Y Oki, H Teraoka, T Kitazawa
Neuropeptide Y (NPY) causes various central and peripheral actions through activation of G-protein-coupled NPY receptors. Although a species-dependent difference in cardiac actions of NPY has been reported, the responses to NPY have not been examined in mice, widely used experimental animals. This study aimed to clarify the responses to NPY and the receptor subtype involved in the responses in mouse atrium. Neuropeptide Y caused negative inotropic and negative chronotropic actions in spontaneous beating right atria...
March 2017: Autonomic & Autacoid Pharmacology
https://www.readbyqxmd.com/read/28529049/heterogeneity-of-transverse-axial-tubule-system-in-mouse-atria-remodeling-in-atrial-specific-na-ca-2-exchanger-knockout-mice
#15
Xin Yue, Rui Zhang, Brian Kim, Aiqun Ma, Kenneth D Philipson, Joshua I Goldhaber
Transverse-axial tubules (TATs) are commonly assumed to be sparse or absent in atrial myocytes from small animals. Atrial myocytes from rats, cats and rabbits lack TATs, which results in a characteristic "V"-shaped Ca release pattern in confocal line-scan recordings due to the delayed rise of Ca in the center of the cell. To examine TAT expression in isolated mouse atrial myocytes, we loaded them with the membrane dye Di-4-ANEPPS to label TATs. We found that >80% of atrial myocytes had identifiable TATs...
May 19, 2017: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/28480585/synthesis-and-biological-evaluation-of-new-combined-%C3%AE-%C3%AE-adrenergic-blockers
#16
Andrej Némethy, Peter Vavrinec, Diana Vavrincová-Yaghi, Diana Čepcová, Svetozár Mišúth, Eva Král'ová, Ružena Čižmáriková, Eva Račanská
The synthesis, characterization, and pharmacological evaluation of new aryloxyaminopropanol compounds based on substituted (4-hydroxyphenyl)ethanone with alterations in the alkoxymethyl side chain in position 2 and with 2-methoxyphenylpiperazine in the basic part of the molecule are reported. For the in vitro pharmacological evaluation, isolated aorta and atria from normotensive Wistar rats were used. Compared to naftopidil, compounds with ethoxymethyl, propoxymethyl, butoxymethyl, and methoxyethoxymethyl substituent displayed similar α1 -adrenolytic potency...
June 2017: Archiv der Pharmazie
https://www.readbyqxmd.com/read/28461771/peroxisome-proliferator-activated-receptor-%C3%AE-is-essential-for-secretion-of-anp-induced-by-prostaglandin-d2-in-the-beating-rat-atrium
#17
Ying Zhang, Xiang Li, Li-Ping Liu, Lan Hong, Xia Liu, Bo Zhang, Cheng-Zhe Wu, Xun Cui
Prostaglandin D2 (PGD2) may act against myocardial ischemia-reperfusion (I/R) injury and play an anti-inflammatory role in the heart. Although the effect of PGD2 in regulation of ANP secretion of the atrium was reported, the mechanisms involved are not clearly identified. The aim of the present study was to investigate whether PGD2 can regulate ANP secretion in the isolated perfused beating rat atrium, and its underlying mechanisms. PGD2 (0.1 to 10 µM) significantly increased atrial ANP secretion concomitantly with positive inotropy in a dose-dependent manner...
May 2017: Korean Journal of Physiology & Pharmacology
https://www.readbyqxmd.com/read/28437860/chronic-inhibition-of-fatty-acid-amide-hydrolase-by-urb597-produces-differential-effects-on-cardiac-performance-in-normotensive-and-hypertensive-rats
#18
Anna Pędzińska-Betiuk, Jolanta Weresa, Marek Toczek, Marta Baranowska-Kuczko, Irena Kasacka, Ewa Harasim-Symbor, Barbara Malinowska
BACKGROUND AND PURPOSE: Fatty acid amide hydrolase (FAAH) inhibitors are postulated to possess anti-hypertensive potential, because their acute injection decreases BP in spontaneously hypertensive rats (SHR), partly through normalization of cardiac contractile function. Here, we examined whether the potential hypotensive effect of chronic FAAH inhibition by URB597 in hypertensive rats correlated with changes in cardiac performance. EXPERIMENTAL APPROACH: Experiments were performed using perfused hearts and left atria isolated from 8- to 10-week-old SHR, age-matched deoxycorticosterone acetate (DOCA)-salt rats and normotensive controls chronically treated with URB597 (1 mg·kg(-1) ) or vehicle...
July 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/28410965/permissive-role-of-reduced-inwardly-rectifying-potassium-current-density-in-the-automaticity-of-the-guinea-pig-pulmonary-vein-myocardium
#19
Yayoi Tsuneoka, Masahiko Irie, Yusuke Tanaka, Takahiko Sugimoto, Yuka Kobayashi, Taichi Kusakabe, Keisuke Kato, Shogo Hamaguchi, Iyuki Namekata, Hikaru Tanaka
The electrophysiological properties underlying the automaticity of the guinea pig pulmonary vein myocardium were studied. About 30% of the isolated pulmonary vein tissue preparations showed spontaneous electrical activity, as shown by glass microelectrode recordings from their myocardial layer. The remaining quiescent preparations had a resting membrane potential less negative than that in the left atria. Blockade of the acetylcholine activated potassium current (IK-ACh) by tertiapin induced a depolarizing shift of the resting membrane potential and automatic electrical activity in the pulmonary vein, but not in the atria...
April 2017: Journal of Pharmacological Sciences
https://www.readbyqxmd.com/read/28386845/sub-physiological-oxygen-levels-optimal-for-growth-and-survival-of-human-atrial-cardiac-stem-cells
#20
Deepthi Sreerengam RajendranNair, Jayakumar Karunakaran, Renuka R Nair
Cardiac stem cells reside in niches where the oxygen levels are close to 3%. For cytotherapy, cells are conventionally expanded in ambient oxygen (21% O2) which represents hyperoxia compared to the oxygen tension of niches. Cardiosphere-derived cells (CDCs) are then transplanted to host tissue with lower-O2 levels. The high-O2 gradient can reduce the efficacy of cultured cells. Based on the assumption that minimizing injury due to O2 gradients will enhance the yield of functionally efficient cells, CDCs were cultured in 3% O2 and compared with cells maintained in ambient O2...
August 2017: Molecular and Cellular Biochemistry
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