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https://www.readbyqxmd.com/read/29733479/levosimendan-differentially-modulates-electrophysiological-activities-of-sinoatrial-nodes-pulmonary-veins-and-the-left-and-right-atria
#1
Yung-Kuo Lin, Yao-Chang Chen, Yi-Ann Chen, Jen-Hung Huang, Shih-Ann Chen, Yi-Jen Chen
INTRODUCTION: Calcium overload increases the risk of atrial fibrillation (AF). Levosimedan, a calcium sensitizer, increases myofilament contractility. Clinical reports suggested that levosimendan might increase AF occurrence, but the electrophysiological effects of levosimendan on AF substrates and triggers (pulmonary veins, PVs) are not clear. METHODS AND RESULTS: Conventional microelectrodes were used to record action potentials (APs) in isolated rabbit PVs, sinoatrial nodes (SANs), the left atrium (LA), and right atrium (RA) before and after application of different concentrations of levosimendan with or without milrinone (a phosphodiesterase (PDE) III inhibitor) and glibenclamide (an ATP-sensitive potassium channel (KATP ) inhibitor)...
May 7, 2018: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/29706431/atrial-remodeling-and-metabolic-dysfunction-in-idiopathic-isolated-fibrotic-atrial-cardiomyopathy
#2
Chang Cui, Xiaohong Jiang, Weizhu Ju, Jiaxian Wang, Daowu Wang, Zheng Sun, Minglong Chen
BACKGROUND: Idiopathic isolated fibrotic atrial cardiomyopathy (IIF-ACM) is a novel subtype of cardiomyopathy characterized by atrial fibrosis that does not involve the ventricular myocardium and is associated with significant atrial tachyarrhythmia. The mechanisms underlying its pathogenesis are unknown. METHODS: Atrium samples were obtained from 3 patients with IIF-ACM via surgical intervention. Control samples were consisted of 3 atrium biopsies from patients with congenital heart disease and normal sinus rhythm, matched for gender, age and basic clinical characteristics...
April 26, 2018: International Journal of Cardiology
https://www.readbyqxmd.com/read/29684589/hydrogen-sulfide-donor-nahs-stimulates-anp-secretion-via-the-k-atp-channel-and-the-nos-sgc-pathway-in-rat-atria
#3
Lamei Yu, Byung Mun Park, Yong Jin Ahn, Gi-Ja Lee, Suhn Hee Kim
Hydrogen sulfide (H2 S) is normally produced from L-cysteine in mammalian tissues and related to the pathogenesis of cardiovascular diseases. The aim of this study is to investigate the effects of H2 S donor on atrial natriuretic peptide (ANP) secretion and define its mechanism using normal and isoproterenol (ISP)-treated rats. Several H2 S donors were perfused into isolated beating rat atria, and atrial pressure (AP) and ANP secretion were measured. NaHS augmented high stretch-induced ANP secretion and decreased AP in a dose-dependent manner...
April 20, 2018: Peptides
https://www.readbyqxmd.com/read/29673908/mechanism-underlying-the-contractile-activity-of-utp-in-the-mammalian-heart
#4
Ulrich Gergs, Daniel Rothkirch, Britt Hofmann, Hendrik Treede, Bernard Robaye, Andreas Simm, Christa E Müller, Joachim Neumann
We previously reported that uridine 5'-triphosphate (UTP), a pyrimidine nucleoside triphosphate produced a concentration- and time-dependent increase in the contraction force in isolated right atrial preparations from patients undergoing cardiac bypass surgery due to angina pectoris. The stimulation of the force of contraction was sustained rather than transient. In the present study, we tried to elucidate the underlying receptor and signal transduction for this effect of UTP. Therefore, we measured the effect of UTP on force of contraction, phosphorylation of p38 and ERK1/2, in human atrial preparations, atrial preparations from genetically modified mice, cardiomyocytes from adult mice and cardiomyocytes from neonatal rats...
April 17, 2018: European Journal of Pharmacology
https://www.readbyqxmd.com/read/29653089/modification-of-levosimendan-induced-suppression-of-atrial-natriuretic-peptide-secretion-in-hypertrophied-rat-atria
#5
Lamei Yu, Kuichang Yuan, Byung Mun Park, Suhn Hee Kim
This study aimed to determine the effects of levosimendan, a calcium sensitizer, on atrial contractility and atrial natriuretic peptide (ANP) secretion and its modification in hypertrophied atria. Isolated perfused beating rat atria were used from control and isoproterenol-treated rats. Levosimendan and its metabolite OR-1896 caused a positive inotropic effect and suppressed ANP secretion in rat atria. Similar to levosimendan, the selective phosphodiesterase 3 (PDE3) or PDE4 inhibitor also suppressed ANP secretion...
April 10, 2018: European Journal of Pharmacology
https://www.readbyqxmd.com/read/29579615/second-generation-cryoballoon-ablation-as-a-first-line-treatment-of-symptomatic-atrial-fibrillation-two-year-outcome-and-predictors-of-recurrence-after-a-single-procedure
#6
Ersan Akkaya, Alexander Berkowitsch, Sergej Zaltsberg, Harald Greiss, Christian W Hamm, Johannes Sperzel, Thomas Neumann, Malte Kuniss
INTRODUCTION: Antiarrhythmic drug (AAD) therapy of patients with atrial fibrillation (AF) has limitations. We investigated the 2-year outcome and pre-procedural predictors of recurrence for first-line catheter ablation using the second-generation cryoballoon (CB-Adv) in a large cohort of patients with symptomatic AF. METHODS AND RESULTS: For this prospective observational study, we enrolled 457 patients with symptomatic AF (278 paroxysmal, 179 persistent) who had no history of AAD use and who underwent pulmonary vein isolation (PVI) with the CB-Adv at our institution...
May 15, 2018: International Journal of Cardiology
https://www.readbyqxmd.com/read/29551001/persistence-of-an-iatrogenic-atrial-septal-defect-after-a-second-generation-cryoballoon-ablation-of-atrial-fibrillation
#7
Tomonori Watanabe, Shinsuke Miyazaki, Takatsugu Kajiyama, Sadamitsu Ichijo, Takamitsu Takagi, Miyako Igarashi, Hiroaki Nakamura, Hiroshi Taniguchi, Hitoshi Hachiya, Yoshito Iesaka
Persistent iatrogenic atrial septal defects (iASDs) can be observed after intervention requiring a left atria (LA) access, including pulmonary vein isolation (PVI) of atrial fibrillation (AF). We investigated the incidence of iASDs post-second-generation cryoballoon ablation and the pre-procedural predictors. Eighty-three paroxysmal AF patients underwent PVI using second-generation cryoballoons. The LA was accessed with single 15-Fr steerable sheaths following a radiofrequency transseptal puncture, and the iASD was evaluated with transthoracic echocardiography (TTE), a median of 9...
March 17, 2018: Heart and Vessels
https://www.readbyqxmd.com/read/29534678/cryoballoon-ablation-for-paroxysmal-atrial-fibrillation-in-a-case-of-persistent-left-superior-vena-cava
#8
Shiwei Huang, Binglin Pan, He Zou, Wei Lin
BACKGROUND: Atrial fibrillation (AF) usually originates from pulmonary veins (PVs) but can also be caused by pulmonary veins outside, such as the coronary sinus (CS), the superior vena cava (SVC), and the ligament of Marshall. CASE PRESENTATION: A 69-year-old male with a history of palpitations for 10 years was referred to our institute because of its recurrence for half a day. A dynamic electrocardiogram revealed sinus rhythm (SR) and paroxysmal AF. Echocardiography demonstrated normal cardiac structure, and physical examination results were unremarkable...
March 13, 2018: BMC Cardiovascular Disorders
https://www.readbyqxmd.com/read/29492394/pre-transplant-ventricular-assist-device-explant
#9
REVIEW
Espeed Khoshbin, Stephan Schueler
Explantation of a left ventricular assist device (LVAD) may be challenging even in the most experienced hands. We aim to describe the technique for explantation of an LVAD together with the heart as applicable to all contemporary implantable mechanical assist devices. In order to ensure safe explantation, particular care must be taken at three distinct stages: at the time of LVAD implantation, at pre-transplant assessment and at the time of heart transplantation. The preparation for a safe explantation at LVAD implantation includes positioning the driveline and the outflow graft away from the back of the sternum to ensure protection from injury during re-entry into the chest...
January 2018: Annals of Cardiothoracic Surgery
https://www.readbyqxmd.com/read/29486618/involvement-of-il-1%C3%AE-and-il-6-in-antiarrhythmic-properties-of-atorvastatin-in-ouabain-induced-arrhythmia-in-rats
#10
Mahya Najjari, Gholamhassan Vaezi, Vida Hojati, Zahra Mousavi, Azam Bakhtiarian, Vahid Nikoui
PURPOSE: Evidence show that statins possess wide beneficial cardioprotective and anti-inflammatory effects; therefore, in the present experiment, we investigated the antiarrhythmic properties of atorvastatin in ouabain-induced arrhythmia in isolated rat atria and the role of several inflammatory cytokines in this effect. MATERIALS AND METHODS: Male rats were pretreated with either of atorvastatin (10 mg/kg) or vehicle, orally once daily for 6 weeks. After induction of anesthesia, we isolated the atria and after incubation with ouabain, time of onset of arrhythmia and asystole as well as atrial beating rate and contractile force were recorded...
February 28, 2018: Immunopharmacology and Immunotoxicology
https://www.readbyqxmd.com/read/29484752/outcome-of-fetuses-with-prenatal-diagnosis-of-isolated-severe-bilateral-ventriculomegaly-a-systematic-review-and-meta-analysis
#11
REVIEW
Silvia Carta, Andrea Kaelin Agten, Chiara Belcaro, Amarnath Bhide
OBJECTIVE: To quantify survival and neurodevelopmental outcome of fetuses with prenatally detected isolated severe bilateral ventriculomegaly form published literature. METHODS: Medline, Embase and the Cochrane Library were searched electronically. Only cases with prenatal diagnosis of apparently isolated severe ventriculomegaly and postnatal neurodevelopment assessment were selected and included. Severe ventriculomegaly was defined by the authors as enlargement of the ventricular atria, with a diameter greater than 15 mm on the transventricular plane while all cases where the investigators were unable to detect associated structural abnormality, chromosomal abnormality or fetal infections, and regarded the ventriculomegaly to be apparently isolated were included...
February 26, 2018: Ultrasound in Obstetrics & Gynecology
https://www.readbyqxmd.com/read/29470593/increased-gi-protein-signaling-potentiates-the-negative-chronotropic-effect-of-adenosine-in-the-shr-right-atrium
#12
Juliano Q D Rodrigues, Henrique Camara, Aron Jurkiewicz, Rosely O Godinho
Hypertension is a risk factor for cardiovascular diseases, which have been associated with dysfunction of sympathetic and purinergic neurotransmission. Therefore, herein, we evaluated whether modifications of adenosine receptor signaling may contribute to the cardiac dysfunction observed in hypertension. Isolated right atria from spontaneously hypertensive (SHR) or normotensive Wistar rats (NWR) were used to investigate the influence of adenosine receptor signaling cascade in the cardiac chronotropism. Our results showed that adenosine, the endogenous agonist of adenosine receptors, and CPA, a selective agonist of A1 receptor, decreased the atrial chronotropism of NWR and SHR in a concentration- and time-dependent manner, culminating in cardiac arrest (0 bpm)...
May 2018: Naunyn-Schmiedeberg's Archives of Pharmacology
https://www.readbyqxmd.com/read/29436789/evaluation-of-chronic-losartan-treatment-effect-on-cardiac-chronotropic-dysfunction-in-biliary-cirrhotic-rats
#13
Farahnaz Jazaeri, Razieh Afsharmoghaddam, Alireza Abdollahi, Giti Ghamami, Ahmad Reza Dehpour
Cirrhosis is associated with cardiac chronotropic and inotropic dysfunction which is known as cirrhotic cardiomyopathy. Cardiac responsiveness to adrenergic stimulation is impaired in cirrhosis. Moreover, there is vagal nerve dysfunction which is related to neuromodulatory dysfunction of the angiotensin II in the cirrhosis. This study was aimed to explore the hypothesis that administration of Losartan-angiotensin II receptor antagonist increases cardiac chronotropic response to isoproterenol in cirrhotic rats; and if so, whether this is associated with altered cardiac TGF-β receptor expression...
January 2018: Acta Medica Iranica
https://www.readbyqxmd.com/read/29429060/electrophysiological-differences-in-cholinergic-signaling-between-the-hearts-of-summer-and-winter-frogs-rana-temporaria
#14
Denis Abramochkin, Vladislav Kuzmin
The striking seasonal difference in sensitivity of frog cardiac muscle to acetylcholine or stimulation of parasympathetic nervous fibers has been noted almost a century ago, although its electrophysiological basis has never been revealed. The present study compares the effects of the muscarinic agonist carbamylcholine chloride (CCh 10-8 -10-5  M) on electrical activity in isolated atrial and ventricular preparations from dormant frogs (Rana temporaria) caught in January (winter-acclimatized, WA) and from active frogs caught in July (summer-acclimatized, SA)...
February 10, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29402528/influence-of-chronic-volume-overload-induced-atrial-remodeling-on-electrophysiological-responses-to-cholinergic-receptor-stimulation-in-the-isolated-rat-atria
#15
Xin Cao, Megumi Aimoto, Marie Fukumoto, Yoshinobu Nagasawa, Hikaru Tanaka, Akira Takahara
Whereas molecular mechanisms of atrial fibrillation (AF) have been widely investigated, there is limited information regarding interrelation between chronic volume overload and parasympathetic nervous system in the pathophysiology of AF. In this study, we investigated the influence of abdominal aorto-venocaval shunt (AVS)-induced atrial remodeling on electrophysiological responses to cholinergic receptor stimulation in the isolated rat atria. Interstitial fibrosis, cardiomyocyte hypertrophy and atrial enlargement, known as structural arrhythmogenic substrates for AF, took place after one month of AVS operation...
February 2018: Journal of Pharmacological Sciences
https://www.readbyqxmd.com/read/29390872/the-potassium-channel-blocker-dalfampridine-diminishes-ouabain-induced-arrhythmia-in-isolated-rat-atria
#16
Nahid Ghebleh Zadeh, Gholamhassan Vaezi, Azam Bakhtiarian, Zahra Mousavi, Abdolhossein Shiravi, Vahid Nikoui
The aim of the present experiment was to investigate the possible antiarrhythmic effects of dalfampridine in ouabain-induced arrhythmia in rats. Twenty-four male rats including the control and dalfampridine-incubated (100 µM to 10 mM) ouabain-stimulated (40 µM) groups were used. After induction of anesthesia, the atria were isolated and the time of onset of arrhythmia and asystole were recorded. The contractile force of atria was also measured. Dalfampridine at concentration of 1 mM significantly postponed the onset of arrhythmia and asystole compared to control group (p ≤ ...
February 1, 2018: Archives of Physiology and Biochemistry
https://www.readbyqxmd.com/read/29377578/luminescent-nanoparticles-for-rapid-monitoring-of-endogenous-acetylcholine-release-in-mice-atria
#17
Alsu Mukhametshina, Alexey Petrov, Svetlana Fedorenko, Konstantin Petrov, Irek Nizameev, Asiya Mustafina, Oleg Sinyashin
The present work introduces for the first time a nanoparticulate approach for ex vivo monitoring of acetylcholinesterase-catalyzed hydrolysis of endogenous acetylcholine released from nerve varicosities in mice atria. Amino-modified 20-nm size silica nanoparticles (SNs) doped by luminescent Tb(III) complexes were applied as the nanosensors. Their sensing capacity results from the decreased intensity of Tb(III)-centred luminescence due to the quenching effect of acetic acid derived from acetylcholinesterase-catalyzed hydrolysis of acetylcholine...
May 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29250296/focal-atrial-fibrillation-from-the-superior-vena-cava
#18
Andres Enriquez, Jackson J Liang, Pasquale Santangeli, Francis E Marchlinski, Michael P Riley
We report the case of a 66 year-old male who underwent catheter ablation for drug-refractory paroxysmal atrial fibrillation (AF) at our institution. Radiofrequency catheter ablation was performed using a three-dimensional electroanatomical mapping system. During ablation of the pulmonary veins (PV), right atrial ectopics were noted to repeatedly trigger AF and atrial tachycardia (AT). After PV isolation, mapping of the right atrium revealed that the superior vena cava (SVC) was in AF, while both atria were in an organized AT...
April 2017: Journal of Atrial Fibrillation
https://www.readbyqxmd.com/read/29218529/quantification-of-cell-surface-glucose-transporters-in-the-heart-using-a-biotinylated-photolabeling-assay
#19
Zahra Maria, Véronique A Lacombe
The biotinylated photolabeling assay enables quantification of cell-surface glucose transporters (GLUTs). This technique has been successfully applied to quantify the cell-surface GLUT protein content in striated muscles and adipose tissue, as a means to evaluate GLUT trafficking. Here, we describe the detailed method of quantifying the cell-surface content of several GLUT isoforms (1, 4, 8, and 12) in isolated cardiac myocytes, as well as in the intact perfused atria and ventricle.
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29212469/orthogonal-p-wave-morphology-is-affected-by-intra-atrial-pressures
#20
Richard Petersson, J Gustav Smith, David A Larsson, Öyvind Reitan, Jonas Carlson, Pyotr Platonov, Fredrik Holmqvist
BACKGROUND: It has previously been shown that the morphology of the P-wave neither depends on atrial size in healthy subjects with physiologically enlarged atria nor on the physiological anatomical variation in transverse orientation of the left atrium. The present study aimed to investigate if different pressures in the left and right atrium are associated with different P-wave morphologies. METHODS: 38 patients with isolated, increased left atrial pressure, 51 patients with isolated, increased right atrial pressure and 76 patients with biatrially increased pressure were studied...
December 6, 2017: BMC Cardiovascular Disorders
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