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Sample records for human atrial septation

  1. Tbx5-hedgehog molecular networks are essential in the second heart field for atrial septation.

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    Xie, Linglin; Hoffmann, Andrew D; Burnicka-Turek, Ozanna; Friedland-Little, Joshua M; Zhang, Ke; Moskowitz, Ivan P

    2012-08-14

    The developmental mechanisms underlying human congenital heart disease (CHD) are poorly understood. Atrial septal defects (ASDs) can result from haploinsufficiency of cardiogenic transcription factors including TBX5. We demonstrated that Tbx5 is required in the second heart field (SHF) for atrial septation in mice. Conditional Tbx5 haploinsufficiency in the SHF but not the myocardium or endocardium caused ASDs. Tbx5 SHF knockout embryos lacked atrial septum progenitors. We found that Tbx5 mutant SHF progenitors demonstrated cell-cycle progression defects and that Tbx5 regulated cell-cycle progression genes including Cdk6. Activated hedgehog (Hh) signaling rescued ASDs in Tbx5 mutant embryos, placing Tbx5 upstream or parallel to Hh in cardiac progenitors. Tbx5 regulated SHF Gas1 and Osr1 expression, supporting both pathways. These results describe a SHF Tbx5-Hh network required for atrial septation. A paradigm defining molecular requirements in SHF cardiac progenitors for cardiac septum morphogenesis has implications for the ontogeny of CHD.

  2. Tbx5-Hedgehog Molecular Networks Are Essential in the Second Heart Field for Atrial Septation

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    Xie, Linglin; Hoffmann, Andrew D.; Burnicka-Turek, Ozanna; Friedland-Little, Joshua M.; Zhang, Ke; Moskowitz, Ivan P.

    2014-01-01

    Summary The developmental mechanisms underlying human congenital heart disease (CHD) are poorly understood. Atrial septal defects (ASDs) can result from haploinsufficiency of cardiogenic transcription factors including TBX5. We demonstrated that Tbx5 is required in the second heart field (SHF) for atrial septation in mice. Conditional Tbx5 haploinsufficiency in the SHF but not the myocardium or endocardium caused ASDs. Tbx5 SHF knockout embryos lacked atrial septum progenitors. We found that Tbx5 mutant SHF progenitors demonstrated cell-cycle progression defects and that Tbx5 regulated cell-cycle progression genes including Cdk6. Activated hedgehog (Hh) signaling rescued ASDs in Tbx5 mutant embryos, placing Tbx5 upstream or parallel to Hh in cardiac progenitors. Tbx5 regulated SHF Gas1 and Osr1 expression, supporting both pathways. These results describe a SHF Tbx5-Hh network required for atrial septation. A paradigm defining molecular requirements in SHF cardiac progenitors for cardiac septum morphogenesis has implications for the ontogeny of CHD. PMID:22898775

  3. Gene network and familial analyses uncover a gene network involving Tbx5/Osr1/Pcsk6 interaction in the second heart field for atrial septation.

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    Zhang, Ke K; Xiang, Menglan; Zhou, Lun; Liu, Jielin; Curry, Nathan; Heine Suñer, Damian; Garcia-Pavia, Pablo; Zhang, Xiaohua; Wang, Qin; Xie, Linglin

    2016-03-15

    Atrial septal defects (ASDs) are a common human congenital heart disease (CHD) that can be induced by genetic abnormalities. Our previous studies have demonstrated a genetic interaction between Tbx5 and Osr1 in the second heart field (SHF) for atrial septation. We hypothesized that Osr1 and Tbx5 share a common signaling networking and downstream targets for atrial septation. To identify this molecular networks, we acquired the RNA-Seq transcriptome data from the posterior SHF of wild-type, Tbx5(+/) (-), Osr1(+/-), Osr1(-/-) and Tbx5(+/-)/Osr1(+/-) mutant embryos. Gene set analysis was used to identify the Kyoto Encyclopedia of Genes and Genomes pathways that were affected by the doses of Tbx5 and Osr1. A gene network module involving Tbx5 and Osr1 was identified using a non-parametric distance metric, distance correlation. A subset of 10 core genes and gene-gene interactions in the network module were validated by gene expression alterations in posterior second heart field (pSHF) of Tbx5 and Osr1 transgenic mouse embryos, a time-course gene expression change during P19CL6 cell differentiation. Pcsk6 was one of the network module genes that were linked to Tbx5. We validated the direct regulation of Tbx5 on Pcsk6 using immunohistochemical staining of pSHF, ChIP-quantitative polymerase chain reaction and luciferase reporter assay. Importantly, we identified Pcsk6 as a novel gene associated with ASD via a human genotyping study of an ASD family. In summary, our study implicated a gene network involving Tbx5, Osr1 and Pcsk6 interaction in SHF for atrial septation, providing a molecular framework for understanding the role of Tbx5 in CHD ontogeny.

  4. Dynamics of AV coupling during human atrial fibrillation: role of atrial rate.

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    Masè, M; Marini, M; Disertori, M; Ravelli, F

    2015-07-01

    The causal relationship between atrial and ventricular activities during human atrial fibrillation (AF) is poorly understood. This study analyzed the effects of an increase in atrial rate on the link between atrial and ventricular activities during AF. Atrial and ventricular time series were determined in 14 patients during the spontaneous acceleration of the atrial rhythm at AF onset. The dynamic relationship between atrial and ventricular activities was quantified in terms of atrioventricular (AV) coupling by AV synchrogram analysis. The technique identified n:m coupling patterns (n atrial beats in m ventricular cycles), quantifying their percentage, maximal length, and conduction ratio (= m/n). Simulations with a difference-equation AV model were performed to correlate the observed dynamics to specific atrial/nodal properties. The atrial rate increase significantly affected AV coupling and ventricular response during AF. The shortening of atrial intervals from 185 ± 32 to 165 ± 24 ms (P AV patterns with progressively decreasing m/n ratios (from conduction ratio = 0.34 ± 0.09 to 0.29 ± 0.08, P AV block and coupling instability at higher atrial rates were associated with increased ventricular interval variability (from 123 ± 52 to 133 ± 55 ms, P AV pattern transitions and coupling instability in patients were predicted, assuming the filtering of high-rate irregular atrial beats by the slow recovery of nodal excitability. These results support the role of atrial rate in determining AV coupling and ventricular response and may have implications for rate control in AF. Copyright © 2015 the American Physiological Society.

  5. Differential gene expression during atrial structural remodeling in human left and right atrial appendages in atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    Hui Zhu; Wei Zhang; Ming Zhong; Gong Zhang; Yun Zhang

    2011-01-01

    Extracellular matrix (ECM) remodeling increases the vulnerability to atrial fibrillation (AF). Some gene expressions are crucial for the metabolism of ECM. The left atrium plays an important role in maintaining AF.However, most studies investigated only the right atrial tissue. We therefore chose human tissue samples from both the left and right atrial to detect the different gene expressions during structural remodeling in AF. The atrial appendages tissue samples from 24 patients with chronic AF and 12 patients with sinus rhythm were obtained when they were undergoing mitral/aortic valve replacement operation. The mRNA levels of matrix metalloproteinases-9 (MMP-9), tissue inhibitor of metalloproteinase-1 (TIMP-1), disintegrin, metalloproteases-15, and integrins β1 were determined by reverse transcriptionpolymerase chain reaction (RT-PCR). in AF group, the level of MMP-9 in left atrial appendage (LAA) was increased (P<0.001), while integrin β1 level was decreased (P< 0.05) compared with those expressed in right atrial appendage (RAA) tissue. The levels of disintegrin, metalloproteinases-15, and TIMP-1 genes in the LAA and RAA had no significant differences. The results demonstrated that the gene expressions in the LAA and RAA are different during AF, which implied that the mechanism of atrial structural remodeling in AF is due to multiple sources and is complicated.

  6. Molecular adaptations in human atrial fibrillation : mechanisms of protein remodeling

    NARCIS (Netherlands)

    Brundel, Bianca Johanna Josephina Maria

    2000-01-01

    The main goal was to study the molecular remodeling in human atrial fibrillation. We focussed on gene expression of proteins wich influence the calcium homeostasis and action potential duration in human AF. The impact of modulation sysems like the natriuretic peptide system and the endothelin system

  7. Electrophysiological effects of hydrogen sulfide on human atrial fibers

    Institute of Scientific and Technical Information of China (English)

    XU Meng; WU Yu-ming; LI Qian; LIU Su; HE Rui-rong

    2011-01-01

    Background It has been reported that endogenous or exogenous hydrogen sulfide (H2S) exerts physiological effects in the vertebrate cardiovascular system.We have also demonstrated that H2S acts as an important regulator of electrophysiological properties in guinea pig papillary muscles and on pacemaker cells in sinoatrial nodes of rabbits.This study was to observe the electrophysiological effects of H2S on human atrial fibers.Methods Human atrial samples were collected during cardiac surgery.Parameters of action potential in human atrial specialized fibers were recorded using a standard intracellular microelectrode technique.Results NaHS (H2S donor) (50,100 and 200 μmol/L) decreased the amplitude of action potential (APA),maximal rate of depolarization (Vmax),velocity of diastolic (phase 4) depolarization (VDD) and rate of pacemaker firing (RPF),and shortened the duration of 90% repolarization (APD90) in a concentration-dependent manner.ATP-sensitive K+ (KATP)channel blocker glibenclamide (Gli,20 μmol/L) partially blocked the effects of NaHS (100 μmol/L) on human atrial fiber cells.The L-type Ca2+ channel agonist Bay K8644 (0.5 μmol/L) also partially blocked the effects of NaHS (100 μmol/L).An inhibitor of cystathionine y-lyase (CSE),DL-propargylglycine (PPG,200 μmol/L),increased APA,Vmax,VDD and RPF,and prolonged APD90.Conclusions H2S exerts a negative chronotropic action and accelerates the repolarization of human atrial specialized fibers,possibly as a result of increases in potassium efflux through the opening of KATP channels and a concomitant decrease in calcium influx.Endogenous H2S may be generated by CSE and act as an important regulator of electrophysiological properties in human atrial fibers.

  8. Ionic Remodeling and Direct Effects of Valsartan on Ionic Currentsin Human Atrial Myocytes with Atrial Fibrillation

    Institute of Scientific and Technical Information of China (English)

    Xue Yumei; Wu Shulin; Deng Chunyu; Qian Weimin; Chen Chunbo

    2004-01-01

    Objectives Previous studies demonstrated that angiotensin receptor antagonists had effects on some potassium channels in guinea pig myocytes and cloned channels that expressed in human cardiac myocytes. This study determined the direct effects of Valsartan on I caL, INa, IKur, IK1 and Ito1 in isolated human atrial myocytes. Methods and Results Specimens of right atrial appendage tissue were obtained from 39 patients with coronary artery and valvular heart diseases during cardiopulmonary bypass procedure. Pre- operation cardiac rhythm was sinus (SR)in 19 patients and was atrial fibrillation (AF) in the others. Single atrial myocyte was isolated by enzymatic dissociation with the chunk method. The ionic currents were recorded using the whole cell coffiguration of the voltage clamp technique. ICaL and Ito1 densities in AF patients were significantly lower than those in SR patients by 74% and 60%, respectively, while IK1density was significantly higher by 34% at command potential of - 120 mV. With 10 μmol/L Valsartan, INa density was significantly decreased by 59% in SR patients and by 66% in AF patients. IKur and IKl density were significantly decreased in only AF patients by 31% and23%, respectively. Conclusions Conclusions Decreased IcaL and Itol and increased IKl at hyperpolarizing potentials in AF patients' atrial myocytes may result from the electrophysiological remodeling by AF. Valsartan significantly decreases INa, IK1 and IKur current densities in AF patients' myocyte, but decreases only INa in SR patients' myocyte, suggesting that Valsartan may be beneficial to the recovering of remolded atria.

  9. Atrial natriuretic peptide induces postprandial lipid oxidation in humans.

    NARCIS (Netherlands)

    Birkenfeld, A.L.; Budziarek, P.; Boschmann, M.; Moro, C.; Adams, F.; Franke, G.; Berlan, M.; Marques, M.A.; Sweep, F.C.; Luft, F.C.; Lafontan, M.; Jordan, J.

    2008-01-01

    OBJECTIVE: Atrial natriuretic peptide (ANP) regulates arterial blood pressure. In addition, ANP has recently been shown to promote human adipose tissue lipolysis through cGMP-mediated hormone-sensitive lipase activation. We hypothesized that ANP increases postprandial free fatty acid (FFA) availabil

  10. Late Sodium Current in Human Atrial Cardiomyocytes from Patients in Sinus Rhythm and Atrial Fibrillation.

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    Poulet, Claire; Wettwer, Erich; Grunnet, Morten; Jespersen, Thomas; Fabritz, Larissa; Matschke, Klaus; Knaut, Michael; Ravens, Ursula

    2015-01-01

    Slowly inactivating Na+ channels conducting "late" Na+ current (INa,late) contribute to ventricular arrhythmogenesis under pathological conditions. INa,late was also reported to play a role in chronic atrial fibrillation (AF). The objective of this study was to investigate INa,late in human right atrial cardiomyocytes as a putative drug target for treatment of AF. To activate Na+ channels, cardiomyocytes from transgenic mice which exhibit INa,late (ΔKPQ), and right atrial cardiomyocytes from patients in sinus rhythm (SR) and AF were voltage clamped at room temperature by 250-ms long test pulses to -30 mV from a holding potential of -80 mV with a 100-ms pre-pulse to -110 mV (protocol I). INa,late at -30 mV was not discernible as deviation from the extrapolated straight line IV-curve between -110 mV and -80 mV in human atrial cells. Therefore, tetrodotoxin (TTX, 10 μM) was used to define persistent inward current after 250 ms at -30 mV as INa,late. TTX-sensitive current was 0.27±0.06 pA/pF in ventricular cardiomyocytes from ΔKPQ mice, and amounted to 0.04±0.01 pA/pF and 0.09±0.02 pA/pF in SR and AF human atrial cardiomyocytes, respectively. With protocol II (holding potential -120 mV, pre-pulse to -80 mV) TTX-sensitive INa,late was always larger than with protocol I. Ranolazine (30 μM) reduced INa,late by 0.02±0.02 pA/pF in SR and 0.09±0.02 pA/pF in AF cells. At physiological temperature (37°C), however, INa,late became insignificant. Plateau phase and upstroke velocity of action potentials (APs) recorded with sharp microelectrodes in intact human trabeculae were more sensitive to ranolazine in AF than in SR preparations. Sodium channel subunits expression measured with qPCR was high for SCN5A with no difference between SR and AF. Expression of SCN8A and SCN10A was low in general, and lower in AF than in SR. In conclusion, We confirm for the first time a TTX-sensitive current (INa,late) in right atrial cardiomyocytes from SR and AF patients at room

  11. Late Sodium Current in Human Atrial Cardiomyocytes from Patients in Sinus Rhythm and Atrial Fibrillation.

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    Claire Poulet

    Full Text Available Slowly inactivating Na+ channels conducting "late" Na+ current (INa,late contribute to ventricular arrhythmogenesis under pathological conditions. INa,late was also reported to play a role in chronic atrial fibrillation (AF. The objective of this study was to investigate INa,late in human right atrial cardiomyocytes as a putative drug target for treatment of AF. To activate Na+ channels, cardiomyocytes from transgenic mice which exhibit INa,late (ΔKPQ, and right atrial cardiomyocytes from patients in sinus rhythm (SR and AF were voltage clamped at room temperature by 250-ms long test pulses to -30 mV from a holding potential of -80 mV with a 100-ms pre-pulse to -110 mV (protocol I. INa,late at -30 mV was not discernible as deviation from the extrapolated straight line IV-curve between -110 mV and -80 mV in human atrial cells. Therefore, tetrodotoxin (TTX, 10 μM was used to define persistent inward current after 250 ms at -30 mV as INa,late. TTX-sensitive current was 0.27±0.06 pA/pF in ventricular cardiomyocytes from ΔKPQ mice, and amounted to 0.04±0.01 pA/pF and 0.09±0.02 pA/pF in SR and AF human atrial cardiomyocytes, respectively. With protocol II (holding potential -120 mV, pre-pulse to -80 mV TTX-sensitive INa,late was always larger than with protocol I. Ranolazine (30 μM reduced INa,late by 0.02±0.02 pA/pF in SR and 0.09±0.02 pA/pF in AF cells. At physiological temperature (37°C, however, INa,late became insignificant. Plateau phase and upstroke velocity of action potentials (APs recorded with sharp microelectrodes in intact human trabeculae were more sensitive to ranolazine in AF than in SR preparations. Sodium channel subunits expression measured with qPCR was high for SCN5A with no difference between SR and AF. Expression of SCN8A and SCN10A was low in general, and lower in AF than in SR. In conclusion, We confirm for the first time a TTX-sensitive current (INa,late in right atrial cardiomyocytes from SR and AF patients at room

  12. A New Dynamic 3D Virtual Methodology for Teaching the Mechanics of Atrial Septation as Seen in the Human Heart

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    Schleich, Jean-Marc; Dillenseger, Jean-Louis; Houyel, Lucile; Almange, Claude; Anderson, Robert H.

    2009-01-01

    Learning embryology remains difficult, since it requires understanding of many complex phenomena. The temporal evolution of developmental events has classically been illustrated using cartoons, which create difficulty in linking spatial and temporal aspects, such correlation being the keystone of descriptive embryology. We synthesized the…

  13. Late Sodium Current in Human Atrial Cardiomyocytes from Patients in Sinus Rhythm and Atrial Fibrillation

    DEFF Research Database (Denmark)

    Poulet, Claire; Wettwer, Erich; Grunnet, Morten

    2015-01-01

    -pulse to -80 mV) TTX-sensitive INa,late was always larger than with protocol I. Ranolazine (30 μM) reduced INa,late by 0.02±0.02 pA/pF in SR and 0.09±0.02 pA/pF in AF cells. At physiological temperature (37°C), however, INa,late became insignificant. Plateau phase and upstroke velocity of action potentials...... to -30 mV from a holding potential of -80 mV with a 100-ms pre-pulse to -110 mV (protocol I). INa,late at -30 mV was not discernible as deviation from the extrapolated straight line IV-curve between -110 mV and -80 mV in human atrial cells. Therefore, tetrodotoxin (TTX, 10 μM) was used to define...... persistent inward current after 250 ms at -30 mV as INa,late. TTX-sensitive current was 0.27±0.06 pA/pF in ventricular cardiomyocytes from ΔKPQ mice, and amounted to 0.04±0.01 pA/pF and 0.09±0.02 pA/pF in SR and AF human atrial cardiomyocytes, respectively. With protocol II (holding potential -120 mV, pre...

  14. Analysis of atrial fibrillatory rate during spontaneous episodes of atrial fibrillation in humans using implantable loop recorder electrocardiogram.

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    Platonov, Pyotr G; Stridh, Martin; de Melis, Mirko; Urban, Lubos; Carlson, Jonas; Corbucci, Giorgio; Holmqvist, Fredrik

    2012-01-01

    Atrial fibrillatory rate (AFR) can predict outcome of interventions for atrial fibrillation (AF); however, AFR behavior at AF onset in humans is poorly described. We studied AFR during spontaneous AF episodes in patients with lone paroxysmal AF who received implantable loop recorders and had AF episodes of 1 hour or more recorded (n = 4). Mean AFR per minute was assessed from continuous implantable loop recorder electrocardiogram using spatiotemporal QRST cancellation and time-frequency analysis. Atrial fibrillatory rate increased from 290 ± 20 to 326 ± 39 fibrillations per minute during the first 3 hours (P<.05) and reached plateau then. Atrial fibrillatory rate beyond the initial 3 hours can, therefore, be considered stable and may be evaluated for prediction of intervention effect.

  15. Echocardiographic evaluation of patent foramen ovale and atrial septal defect.

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    Hari, Pawan; Pai, Ramdas G; Varadarajan, Padmini

    2015-01-01

    Patent foramen ovale (PFO) is a common variant present in up to 25% of the population. Atrial septal defect (ASD) is a direct communication between the 2 atrial chambers, of which the ostium secundum variety is the most common. This manuscript is an in depth review of the complex atrial septation, the diagnosis of PFO and ASD and its clinical and therapeutic implications.

  16. Identification and purification of human induced pluripotent stem cell-derived atrial-like cardiomyocytes based on sarcolipin expression.

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    Rebecca Josowitz

    Full Text Available The use of human stem cell-derived cardiomyocytes to study atrial biology and disease has been restricted by the lack of a reliable method for stem cell-derived atrial cell labeling and purification. The goal of this study was to generate an atrial-specific reporter construct to identify and purify human stem cell-derived atrial-like cardiomyocytes. We have created a bacterial artificial chromosome (BAC reporter construct in which fluorescence is driven by expression of the atrial-specific gene sarcolipin (SLN. When purified using flow cytometry, cells with high fluorescence specifically express atrial genes and display functional calcium handling and electrophysiological properties consistent with atrial cardiomyocytes. Our data indicate that SLN can be used as a marker to successfully monitor and isolate hiPSC-derived atrial-like cardiomyocytes. These purified cells may find many applications, including in the study of atrial-specific pathologies and chamber-specific lineage development.

  17. Nodal recovery, dual pathway physiology, and concealed conduction determine complex AV dynamics in human atrial tachyarrhythmias.

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    Masè, Michela; Glass, Leon; Disertori, Marcello; Ravelli, Flavia

    2012-11-15

    The genesis of complex ventricular rhythms during atrial tachyarrhythmias in humans is not fully understood. To clarify the dynamics of atrioventricular (AV) conduction in response to a regular high-rate atrial activation, 29 episodes of spontaneous or pacing-induced atrial flutter (AFL), covering a wide range of atrial rates (cycle lengths from 145 to 270 ms), were analyzed in 10 patients. AV patterns were identified by applying firing sequence and surrogate data analysis to atrial and ventricular activation series, whereas modular simulation with a difference-equation AV node model was used to correlate the patterns with specific nodal properties. AV node response at high atrial rate was characterized by 1) AV patterns of decreasing conduction ratios at the shortening of atrial cycle length (from 236.3 ± 32.4 to 172.6 ± 17.8 ms) according to a Farey sequence ordering (conduction ratio from 0.34 ± 0.12 to 0.23 ± 0.06; P AV block patterns occurring during regular atrial tachyarrhythmias. The characterization of AV nodal function during different AFL forms constitutes an intermediate step toward the understanding of complex ventricular rhythms during atrial fibrillation.

  18. Immunohistochemical expression of atrial natriuretic peptide (ANP) in the conducting system and internodal atrial myocardium of human hearts.

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    Benvenuti, L A; Aiello, V D; Higuchi, M de L; Palomino, S A

    1997-06-01

    Expression and distribution of atrial natriuretic peptide (ANP) were studied immunohistochemically in the conducting system and internodal atrial myocardium of 5 adult human hearts. Myocytes from the sinus node and compact atrioventricular node were usually ANP-negative; only a very few cells exhibited ANP immunoreactivity. These ANP-positive myocytes were small and did not appear to be trapped working atrial myocytes which are larger than nodal cells. The transitional cell zones of the sinus node and the atrioventricular node were composed of bundles of ANP-positive myocytes, intermingled with non-reactive myocytes. The internodal atrial myocardium exhibited a comparable intensity of myocyte staining in each case examined. Thus, morphologically distinct connecting pathways between the sinus node and the atrioventricular node with regard to myocyte ANP immunoreactivity could not be demonstrated, reinforcing the notion that they actually do not exist. The penetrating bundle, branching bundle and bundle branches were usually composed of ANP-negative myocytes although some ANP-positive myocytes were observed in the branching bundle and bundle branches in 4 cases. Myocytes from the ventricular conducting tissue presenting ANP immunoreactivity have been designated Purkinje fibers and have been found in several mammalian species.

  19. Effects of Persistent Atrial Fibrillation-Induced Electrical Remodeling on Atrial Electro-Mechanics – Insights from a 3D Model of the Human Atria

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    Adeniran, Ismail; MacIver, David H.; Garratt, Clifford J.; Ye, Jianqiao; Hancox, Jules C.; Zhang, Henggui

    2015-01-01

    Aims Atrial stunning, a loss of atrial mechanical contraction, can occur following a successful cardioversion. It is hypothesized that persistent atrial fibrillation-induced electrical remodeling (AFER) on atrial electrophysiology may be responsible for such impaired atrial mechanics. This simulation study aimed to investigate the effects of AFER on atrial electro-mechanics. Methods and Results A 3D electromechanical model of the human atria was developed to investigate the effects of AFER on atrial electro-mechanics. Simulations were carried out in 3 conditions for 4 states: (i) the control condition, representing the normal tissue (state 1) and the tissue 2–3 months after cardioversion (state 2) when the atrial tissue recovers its electrophysiological properties after completion of reverse electrophysiological remodelling; (ii) AFER-SR condition for AF-remodeled tissue with normal sinus rhythm (SR) (state 3); and (iii) AFER-AF condition for AF-remodeled tissue with re-entrant excitation waves (state 4). Our results indicate that at the cellular level, AFER (states 3 & 4) abbreviated action potentials and reduced the Ca2+ content in the sarcoplasmic reticulum, resulting in a reduced amplitude of the intracellular Ca2+ transient leading to decreased cell active force and cell shortening as compared to the control condition (states 1 & 2). Consequently at the whole organ level, atrial contraction in AFER-SR condition (state 3) was dramatically reduced. In the AFER-AF condition (state 4) atrial contraction was almost abolished. Conclusions This study provides novel insights into understanding atrial electro-mechanics illustrating that AFER impairs atrial contraction due to reduced intracellular Ca2+ transients. PMID:26606047

  20. SEPTATE GALLBLADDER - A RARE CASE REPORT

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    Santhosh Kumar

    2016-10-01

    Full Text Available BACKGROUND Septate gallbladders are rare variations associated with the extrahepatic biliary system. The present report is a morphological study of a septate gallbladder. Septations in the gallbladder have been reported to be single or multiple. In our case, we report gallbladder was found to have multiple septa extending into the whole cavity. The cystic duct and artery were single and normal. Histology revealed marked smooth muscle hyperplasia with prominent septa with Aschoff Rokitansky sinuses

  1. Difference of Sodium Currents between Pediatric and Adult Human Atrial Myocytes: Evidence for Developmental Changes of Sodium Channels

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    Benzhi Cai, Xiaoqin Mu, Dongmei Gong, Shulin Jiang, Jianping Li, Qingxin Meng, Yunlong Bai, Yanju Liu, Xinyue Wang, Xueying Tan, Baofeng Yang, Yanjie Lu

    2011-01-01

    Full Text Available Voltage-gated calcium currents and potassium currents were shown to undergo developmental changes in postnatal human and animal cardiomocytes. However, so far, there is no evidence whether sodium currents also presented the developmental changes in postnatal human atrial cells. The aim of this study was to observe age-related changes of sodium currents between pediatric and adult atrial myocytes. Human atrial myocytes were acutely isolated and the whole-cell patch clamp technique was used to record sodium currents isolated from pediatric and adult atrial cardiomocytes. The peak amplitude of sodium currents recorded in adult atrial cells was significantly larger than that in pediatric atrial myocytes. However, there was no significant difference of the activation voltage for peak sodium currents between two kinds of atrial myocytes. The time constants for the activation and inactivation of sodium currents were smaller in adult atria than pediatric atria. The further study revealed that the voltage-dependent inactivation of sodium currents were more slow in adult atrial cardiomyocytes than pediatric atrial cells. A significant difference was also observed in the recovery process of sodium channel from inactivation. In summary, a few significant differences were demonstrated in sodium currents characteristics between pediatric and adult atrial myocytes, which indicates that sodium currents in human atria also undergo developmental changes.

  2. Effects of NIP-141 on K currents in human atrial myocytes.

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    Seki, Akiko; Hagiwara, Nobuhisa; Kasanuki, Hiroshi

    2002-01-01

    A novel benzopyran derivative, NIP-141, effectively terminates experimental atrial fibrillation in canine hearts by prolonging atrial refractoriness. However, the effects of this drug on human atrial myocytes are unknown. This experiment evaluated the effects of NIP-141 on K currents in isolated human atrial myocytes using a whole-cell voltage-clamp method. NIP-141 inhibited the transient outward current (I(to)) and the ultra-rapid delayed rectifier K current (I(Kur)), each in a dose-dependent manner, with half-maximal inhibition concentrations of 16.3 microM and 5.3 microM, respectively (n = 5). NIP-141 inhibited both K currents in a voltage- and use-independent fashion, and it preferentially blocked them in the open state and dissociated rapidly from the channel. Because both K currents contribute significantly to the repolarization of the atrial action potential, these findings suggest that NIP-141 may terminate atrial fibrillation by prolonging action potential duration.

  3. Hypertension is associated with preamyloid oligomers in human atrium: a missing link in atrial pathophysiology?

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    Sidorova, Tatiana N; Mace, Lisa C; Wells, K Sam; Yermalitskaya, Liudmila V; Su, Pei-Fang; Shyr, Yu; Atkinson, James B; Fogo, Agnes B; Prinsen, Joseph K; Byrne, John G; Petracek, Michael R; Greelish, James P; Hoff, Steven J; Ball, Stephen K; Glabe, Charles G; Brown, Nancy J; Barnett, Joey V; Murray, Katherine T

    2014-12-02

    Increasing evidence indicates that proteotoxicity plays a pathophysiologic role in experimental and human cardiomyopathy. In organ-specific amyloidoses, soluble protein oligomers are the primary cytotoxic species in the process of protein aggregation. While isolated atrial amyloidosis can develop with aging, the presence of preamyloid oligomers (PAOs) in atrial tissue has not been previously investigated. Atrial samples were collected during elective cardiac surgery in patients without a history of atrial arrhythmias, congestive heart failure, cardiomyopathy, or amyloidosis. Immunohistochemistry was performed for PAOs using a conformation-specific antibody, as well as for candidate proteins identified previously in isolated atrial amyloidosis. Using a myocardium-specific marker, the fraction of myocardium colocalizing with PAOs (PAO burden) was quantified (green/red ratio). Atrial samples were obtained from 92 patients, with a mean age of 61.7±13.8 years. Most patients (62%) were male, 23% had diabetes, 72% had hypertension, and 42% had coronary artery disease. A majority (n=62) underwent aortic valve replacement, with fewer undergoing coronary artery bypass grafting (n=34) or mitral valve replacement/repair (n=24). Immunostaining detected intracellular PAOs in a majority of atrial samples, with a heterogeneous distribution throughout the myocardium. Mean green/red ratio value for the samples was 0.11±0.1 (range 0.03 to 0.77), with a value ≥0.05 in 74 patients. Atrial natriuretic peptide colocalized with PAOs in myocardium, whereas transthyretin was located in the interstitium. Adjusting for multiple covariates, PAO burden was independently associated with the presence of hypertension. PAOs are frequently detected in human atrium, where their presence is associated with clinical hypertension. © 2014 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  4. Molecular mechanisms of remodeling in human atrial fibrillation

    NARCIS (Netherlands)

    Brundel, BJJM; Henning, RH; Kampinga, HH; Van Gelder, IC; Crijns, HJGM

    2002-01-01

    An important acknowledgement of the last several years is that atrial fibrillation (AF) modifies the electrical properties of the atrium in a way that promotes its occurrence and maintenance. This arrhythmogenic electrophysiological remodeling is well established, but can not explain by itself that

  5. T wave alternans during exercise and atrial pacing in humans

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    Hohnloser, S. H.; Klingenheben, T.; Zabel, M.; Li, Y. G.; Albrecht, P.; Cohen, R. J.

    1997-01-01

    INTRODUCTION: Evidence is accumulating that microvolt T wave alternans (TWA) is a marker of increased risk for ventricular tachyarrhythmias. Initially, atrial pacing was used to elevate heart rate and elicit TWA. More recently, a noninvasive approach has been developed that elevates heart rate using exercise. METHODS AND RESULTS: In 30 consecutive patients with a history of ventricular tachyarrhythmias, the spectral method was used to detect TWA during both atrial pacing and submaximal exercise testing. The concordance rate for the presence or absence of TWA using the two measurement methods was 84%. There was a patient-specific heart rate threshold for the detection of TWA that averaged 100 +/- 14 beats/min during exercise compared with 97 +/- 9 beats/min during right atrial pacing (P = NS). Beyond this threshold, there was a significant and comparable increase in level of TWA with decreasing pacing cycle length and increasing exercise heart rates. CONCLUSIONS: The present study is the first to demonstrate that microvolt TWA can be assessed reliably and noninvasively during exercise stress. There is a patient-specific heart rate threshold beyond which TWA continues to increase with increasing heart rates. Heart rate thresholds for the onset of TWA measured during atrial pacing and exercise stress were comparable, indicating that heart rate alone appears to be the main factor of determining the onset of TWA during submaximal exercise stress.

  6. Block of Na(+)/Ca(2+) exchanger by SEA0400 in human right atrial preparations from patients in sinus rhythm and in atrial fibrillation.

    Science.gov (United States)

    Christ, Torsten; Kovács, Peter P; Acsai, Karoly; Knaut, Michael; Eschenhagen, Thomas; Jost, Norbert; Varró, András; Wettwer, Erich; Ravens, Ursula

    2016-10-01

    The Na(+)/Ca(2+) exchanger (NCX) plays a major role in myocardial Ca(2+) homoeostasis, but is also considered to contribute to the electrical instability and contractile dysfunction in chronic atrial fibrillation (AF). Here we have investigated the effects of the selective NCX blocker SEA0400 in human right atrial cardiomyocytes from patients in sinus rhythm (SR) and AF in order to obtain electrophysiological evidence for putative antiarrhythmic activity of this new class of drugs. Action potentials were measured in right atrial trabeculae using conventional microelectrodes. Human myocytes were enzymatically isolated. Rat atrial and ventricular cardiomyocytes were used for comparison. Using perforated-patch, NCX was measured as Ni(2+)-sensitive current during ramp pulses. In ruptured-patch experiments, NCX current was activated by changing the extracellular Ca(2+) concentration from 0 to 1mM in Na(+)-free bath solution (100mM Na(+) intracellular, "Hilgemann protocol"). Although SEA0400 was effective in rat cardiomyocytes, 10µM did not influence action potentials and contractility, neither in SR nor AF. SEA0400 (10μM) also failed to affect human atrial NCX current measured with perforated patch. With the "Hilgemann protocol" SEA0400 concentration-dependently suppressed human atrial NCX current, and its amplitude was larger in AF than in SR cardiomyocytes. Our results confirm higher NCX activity in AF than SR. SEA0400 fails to block Ni(2+)-sensitive current in human atrial cells unless unphysiological conditions are used. We speculate that block of NCX with SEA0400 depends on intracellular Na(+) concentration.

  7. Splanchnic removal of human alpha-atrial natriuretic peptide in humans: enhancement after food intake

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik; Bendtsen, Flemming; Gerbes, A L

    1990-01-01

    In order to assess the effect of food ingestion on splanchnic disposal of human alpha-atrial natriuretic peptide (ANF), hepatic-intestinal removal of ANF was determined before and after a test meal. Hepatic venous and arterial plasma samples were obtained from six subjects, most of whom had only...... disorders of minor degree. Hepatic blood flow (HBF) increased significantly after meal ingestion (1.10 +/- 0.17 [SEM] to 1.51 +/- 0.26 L/min, P less than .01). Baseline arterial ANF (10.9 +/- 3.1 pmol/L) did not change significantly. In contrast, hepatic venous ANF increased after meal intake (5.7 +/- 2...

  8. Splanchnic removal of human alpha-atrial natriuretic peptide in humans: enhancement after food intake

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Bendtsen, F; Gerbes, A L

    1990-01-01

    In order to assess the effect of food ingestion on splanchnic disposal of human alpha-atrial natriuretic peptide (ANF), hepatic-intestinal removal of ANF was determined before and after a test meal. Hepatic venous and arterial plasma samples were obtained from six subjects, most of whom had only...... .05). Splanchnic removal of ANF was 3.0 +/- 0.5 pmol/min before and increased to a maximum value (7.1 +/- 2.2 pmol/min, P less than .05) 35 minutes after ingestion of the meal. Our results showed enhanced splanchnic removal of ANF after food intake. This is due to increased hepatic...

  9. 3D virtual human atria: A computational platform for studying clinical atrial fibrillation.

    Science.gov (United States)

    Aslanidi, Oleg V; Colman, Michael A; Stott, Jonathan; Dobrzynski, Halina; Boyett, Mark R; Holden, Arun V; Zhang, Henggui

    2011-10-01

    Despite a vast amount of experimental and clinical data on the underlying ionic, cellular and tissue substrates, the mechanisms of common atrial arrhythmias (such as atrial fibrillation, AF) arising from the functional interactions at the whole atria level remain unclear. Computational modelling provides a quantitative framework for integrating such multi-scale data and understanding the arrhythmogenic behaviour that emerges from the collective spatio-temporal dynamics in all parts of the heart. In this study, we have developed a multi-scale hierarchy of biophysically detailed computational models for the human atria--the 3D virtual human atria. Primarily, diffusion tensor MRI reconstruction of the tissue geometry and fibre orientation in the human sinoatrial node (SAN) and surrounding atrial muscle was integrated into the 3D model of the whole atria dissected from the Visible Human dataset. The anatomical models were combined with the heterogeneous atrial action potential (AP) models, and used to simulate the AP conduction in the human atria under various conditions: SAN pacemaking and atrial activation in the normal rhythm, break-down of regular AP wave-fronts during rapid atrial pacing, and the genesis of multiple re-entrant wavelets characteristic of AF. Contributions of different properties of the tissue to mechanisms of the normal rhythm and arrhythmogenesis were investigated. Primarily, the simulations showed that tissue heterogeneity caused the break-down of the normal AP wave-fronts at rapid pacing rates, which initiated a pair of re-entrant spiral waves; and tissue anisotropy resulted in a further break-down of the spiral waves into multiple meandering wavelets characteristic of AF. The 3D virtual atria model itself was incorporated into the torso model to simulate the body surface ECG patterns in the normal and arrhythmic conditions. Therefore, a state-of-the-art computational platform has been developed, which can be used for studying multi

  10. The relationship between gap junctional remodeling and human atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    李大强; 冯义柏; 张会琴

    2004-01-01

    @@ Atrial fibrillation (AF) is currently the most common cardiac tachyarrhythmia in clinical practice. AF has a tendency to become more persistent over time. Progression of an underlying disease is one explanation. Another possible explanation is electrical, structural, and gap junctional remodeling of the atrium by repetitive induction of AF.1 The expression level and distribution of it have close relation with the conduction velocity of electrical activation in the atrium. The aim of the present study was to investigate the alternations of the expression and distribution of (connexin 40, Cx 40) and (connexin 43, Cx 43) in the right atrial appendages of the patients with AF by laser confocal scanning microscopy and Western blot technique.

  11. Atrial distension, haemodilution, and acute control of renin release during water immersion in humans

    DEFF Research Database (Denmark)

    Gabrielsen, A; Pump, B; Bie, P;

    2002-01-01

    We tested the hypothesis that atrial distension (stimulation of cardiopulmonary baroreceptors) is not the single pivotal stimulus for the acute suppression of renin release during water immersion in humans and that immersion-induced haemodilution constitutes an important additional stimulus...... immersion. During WI, central venous pressure (CVP) and left atrial diameter (LAD) increased (P mL(-1) h......), and markedly inhibited suppression of PRA, which decreased by 0.4 +/- 0.1 ng mL(-1) h(-1) (to 87 +/- 4% of baseline values, P

  12. Slow conduction in the border zones of patchy fibrosis stabilises the drivers for atrial fibrillation: Insights from multi-scale human atrial modelling

    Directory of Open Access Journals (Sweden)

    Ross Morgan

    2016-10-01

    Full Text Available 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 fibre orientation, region-specific electrophysiology and AF-induced ionic remodelling. A novel detailed model for an atrial fibroblast was developed, and effects of myocyte-fibroblast (M-F coupling were explored at single-cell, 1D tissue and 3D atria levels. Left atrial LGE MRI datasets from 3 chronic AF patients were segmented to provide the patient-specific distributions of fibrosis. The data was non-linearly registered and mapped to the 3D atria model. Six distinctive fibrosis levels (0 – healthy tissue, 5 – dense fibrosis were identified based on LGE MRI intensity and modelled as progressively increasing M-F coupling and decreasing atrial tissue coupling. Uniform 3D atrial model with diffuse (level 2 fibrosis was considered for comparison.Results. In single cells and tissue, the largest effect of atrial M-F coupling was on the myocyte resting membrane potential, leading to partial inactivation of sodium current and reduction of conduction velocity (CV. In the 3D atria, further to the M-F coupling, effects of fibrosis on tissue coupling greatly reduce atrial CV. AF was initiated by fast pacing in each 3D model with either uniform or patient-specific fibrosis. High variation in fibrosis distributions between the models resulted in varying complexity of AF, with several drivers emerging. In the diffuse fibrosis models, waves randomly meandered through the atria, whereas in each the patient-specific models, rotors

  13. Simulation of biatrial conduction via different pathways during sinus rhythm with a detailed human atrial model

    Institute of Scientific and Technical Information of China (English)

    Dong-dong DENG; Ying-lan GONG; Guo-fa SHOU; Pei-feng JIAO; Heng-gui ZHANG; Xue-song YE; Ling XIA

    2012-01-01

    In order to better understand biatrial conduction,investigate various conduction pathways,and compare the differences between isotropic and anisotropic conductions in human atria,we present a simulation study of biatrial conduction with known/assumed conduction pathways using a recently developed human atrial model.In addition to known pathways:(1) Bachmann's bundle (BB),(2) limbus of fossa ovalis (LFO),and (3) coronary sinus (CS),we also hypothesize that there exist two fast conduction bundles that connect the crista terminalis (CT),LFO,and CS.Our simulation demonstrates that use of these fast conduction bundles results in a conduction pattern consistent with experimental data.The comparison of isotropic and anisotropoic conductions in the BB case showed that the atrial working muscles had small effect on conduction time and conduction speed,although the conductivities assigned in anisotropic conduction were two to four times higher than the isotropic conduction.In conclusion,we suggest that the hypothesized intercaval bundles play a significant role in the biatrial conduction and that myofiber orientation has larger effects on the conduction system than the atrial working muscles.This study presents readers with new insights into human atrial conduction.

  14. Pharmacologic Atrial Natriuretic Peptide Reduces Human Leg Capillary Filtration

    Science.gov (United States)

    Watenpaugh, Donald E.; Vissing, Susanne F.; Lane, Lynda D.; Buckey, Jay C.; Firth, Brian G.; Erdman, William; Hargens, Alan R.; Blomqvist, C. Gunnar

    1995-01-01

    Atrial natriuretic peptide (ANP) is produced and secreted by atrial cells. We measured calf capillary filtration rate with prolonged venous-occlusion plethys-mography of supine health male subjects during pharmacologic infusion of ANP (48 pmol/kg/min for 15 min; n equals 6) and during placebo infusion (n equals 7). Results during infusions were compared to prior control measurements. ANP infusion increased plasma (ANP) from 30 plus or minus 4 to 2,568 plus or minus 595 pmol/L. Systemic hemoconcentration occurred during ANP infusion; mean hematocrit and plasma colloid osmotic pressure increased 4.6 and 11.3 percent respectively, relative to pre-infusion baseline values (p is less than 0.05). Mean calf filtration, however was significantly reduced from 0.15 to 0.08 ml/100 ml/min with ANP. Heart rate increased 20 percent with ANP infusion, wheras blood pressure was unchanged. Calf conductance (blood flow/arterial pressure) and venous compliance were unaffected by ANP infusion. Placebo infusion had no effect relative to prior baseline control measurements. Although ANP induced systemic capillary filtration, in the calf, filtration was reduced with ANP. Therefore, phamacologic ANP infusion enhances capillary filtration from the systemic circulation, perhaps at upper body or splanchic sites or both, while having the opposite effect in the leg.

  15. Simulation of biatrial conduction via different pathways during sinus rhythm with a detailed human atrial model*

    OpenAIRE

    Deng, Dong-dong; Gong, Ying-lan; Shou, Guo-fa; Jiao, Pei-feng; Zhang, Heng-gui; Ye, Xue-song; Xia, Ling

    2012-01-01

    In order to better understand biatrial conduction, investigate various conduction pathways, and compare the differences between isotropic and anisotropic conductions in human atria, we present a simulation study of biatrial conduction with known/assumed conduction pathways using a recently developed human atrial model. In addition to known pathways: (1) Bachmann’s bundle (BB), (2) limbus of fossa ovalis (LFO), and (3) coronary sinus (CS), we also hypothesize that there exist two fast conducti...

  16. Atrial Ectopics Precipitating Atrial Fibrillation

    OpenAIRE

    Johnson Francis

    2015-01-01

    Holter monitor tracing showing blocked atrial ectopics and atrial ectopic precipitating atrial fibrillation is being demonstrated. Initially it was coarse atrial fibrillation, which rapidly degenerated into fine atrial fibrillation.

  17. Atrial Fibrillation associated chromosome 4q25 variants are not associated with PITX2c expression in human adult left atrial appendages.

    Directory of Open Access Journals (Sweden)

    Shamone R Gore-Panter

    Full Text Available Atrial Fibrillation (AF, the most common sustained arrhythmia, has a strong genetic component, but the mechanism by which common genetic variants lead to increased AF susceptibility is unknown. Genome-wide association studies (GWAS have identified that the single nucleotide polymorphisms (SNPs most strongly associated with AF are located on chromosome 4q25 in an intergenic region distal to the PITX2 gene. Our objective was to determine whether the AF-associated SNPs on chromosome 4q25 were associated with PITX2c expression in adult human left atrial appendages. Analysis of a lone AF GWAS identified four independent AF risk SNPs at chromosome 4q25. Human adult left atrial appendage tissue was obtained from 239 subjects of European Ancestry and used for SNP analysis of genomic DNA and determination of PITX2c RNA expression levels by quantitative PCR. Subjects were divided into three groups based on their history of AF and pre-operative rhythm. AF rhythm subjects had higher PITX2c expression than those with history of AF but in sinus rhythm. PITX2c expression was not associated with the AF risk SNPs in human adult left atrial appendages in all subjects combined or in each of the three subgroups. However, we identified seven SNPs modestly associated with PITX2c expression located in the introns of the ENPEP gene, ∼54 kb proximal to PITX2. PITX2c expression in human adult left atrial appendages is not associated with the chromosome 4q25 AF risk SNPs; thus, the mechanism by which these SNPs are associated with AF remains enigmatic.

  18. Evolution and development of ventricular septation in the amniote heart.

    Science.gov (United States)

    Poelmann, Robert E; Gittenberger-de Groot, Adriana C; Vicente-Steijn, Rebecca; Wisse, Lambertus J; Bartelings, Margot M; Everts, Sonja; Hoppenbrouwers, Tamara; Kruithof, Boudewijn P T; Jensen, Bjarke; de Bruin, Paul W; Hirasawa, Tatsuya; Kuratani, Shigeru; Vonk, Freek; van de Put, Jeanne M M S; de Bakker, Merijn A; Richardson, Michael K

    2014-01-01

    During cardiogenesis the epicardium, covering the surface of the myocardial tube, has been ascribed several functions essential for normal heart development of vertebrates from lampreys to mammals. We investigated a novel function of the epicardium in ventricular development in species with partial and complete septation. These species include reptiles, birds and mammals. Adult turtles, lizards and snakes have a complex ventricle with three cava, partially separated by the horizontal and vertical septa. The crocodilians, birds and mammals with origins some 100 million years apart, however, have a left and right ventricle that are completely separated, being a clear example of convergent evolution. In specific embryonic stages these species show similarities in development, prompting us to investigate the mechanisms underlying epicardial involvement. The primitive ventricle of early embryos becomes septated by folding and fusion of the anterior ventricular wall, trapping epicardium in its core. This folding septum develops as the horizontal septum in reptiles and the anterior part of the interventricular septum in the other taxa. The mechanism of folding is confirmed using DiI tattoos of the ventricular surface. Trapping of epicardium-derived cells is studied by transplanting embryonic quail pro-epicardial organ into chicken hosts. The effect of decreased epicardium involvement is studied in knock-out mice, and pro-epicardium ablated chicken, resulting in diminished and even absent septum formation. Proper folding followed by diminished ventricular fusion may explain the deep interventricular cleft observed in elephants. The vertical septum, although indistinct in most reptiles except in crocodilians and pythonidsis apparently homologous to the inlet septum. Eventually the various septal components merge to form the completely septated heart. In our attempt to discover homologies between the various septum components we aim to elucidate the evolution and development

  19. Evolution and development of ventricular septation in the amniote heart.

    Directory of Open Access Journals (Sweden)

    Robert E Poelmann

    Full Text Available During cardiogenesis the epicardium, covering the surface of the myocardial tube, has been ascribed several functions essential for normal heart development of vertebrates from lampreys to mammals. We investigated a novel function of the epicardium in ventricular development in species with partial and complete septation. These species include reptiles, birds and mammals. Adult turtles, lizards and snakes have a complex ventricle with three cava, partially separated by the horizontal and vertical septa. The crocodilians, birds and mammals with origins some 100 million years apart, however, have a left and right ventricle that are completely separated, being a clear example of convergent evolution. In specific embryonic stages these species show similarities in development, prompting us to investigate the mechanisms underlying epicardial involvement. The primitive ventricle of early embryos becomes septated by folding and fusion of the anterior ventricular wall, trapping epicardium in its core. This folding septum develops as the horizontal septum in reptiles and the anterior part of the interventricular septum in the other taxa. The mechanism of folding is confirmed using DiI tattoos of the ventricular surface. Trapping of epicardium-derived cells is studied by transplanting embryonic quail pro-epicardial organ into chicken hosts. The effect of decreased epicardium involvement is studied in knock-out mice, and pro-epicardium ablated chicken, resulting in diminished and even absent septum formation. Proper folding followed by diminished ventricular fusion may explain the deep interventricular cleft observed in elephants. The vertical septum, although indistinct in most reptiles except in crocodilians and pythonidsis apparently homologous to the inlet septum. Eventually the various septal components merge to form the completely septated heart. In our attempt to discover homologies between the various septum components we aim to elucidate the

  20. Some aspects of the mitochondrial oxidative metabolism in human atrial tissue during cardiopulmonary by-pass.

    Science.gov (United States)

    Corbucci, G G; Gasparetto, A; Antonelli, M; Bufi, M; De Blasi, R A

    1987-01-01

    Following previous research on the hypoxic cell in human circulatory shock, the present work has investigated some mitochondrial oxidative aspects in atrial biopsies taken during cardiopulmonary by-pass. Cardioplegic solution and hypothermia were administered to 10 patients and the atrial samples were collected before and after aortic clamping. The results show a cellular protective effect of cardioplegia and hypothermia on the electron-transport chain, even if the enzymes with high KmO2 appear to be more sensitive to ischaemia. The results suggest a metabolic injury rather than an oxidative damage due to the induced ischaemia, alterations to fatty-acid beta-oxidation being especially notable. Because of the unchanged oxidative capacities, the oxyradical generation and the peroxidative damage appear to be irrelevant in the ischaemic period and during the course of reperfusion. Further studies are needed to elucidate the metabolic damage and the therapeutic implications due to the induced ischaemia in the myocardial cell during the aortic clamping.

  1. Direct differentiation of atrial and ventricular myocytes from human embryonic stem cells by alternating retinoid signals

    Institute of Scientific and Technical Information of China (English)

    Qiangzhe Zhang; Li Chen; Tian Tian; Xin Wang; Pu Li; Jurgen Hescheler; Guangju Ji; Yue Ma; Junjie Jiang; Pengcheng Han; Qi Yuan; Jing Zhang; Xiaoqian Zhang; Yanyan Xu; Henghua Cao; Qingzhang Meng

    2011-01-01

    Although myocyte cell transplantation studies have suggested a promising therapeutic potential for myocardial infarction, a major obstacle to the development of clinical therapies for myocardial repair is the difficulties associated with obtaining relatively homogeneous ventricular myocytes for transplantation. Human embryonic stem cells (hESCs)are a promising source of cardiomyocytes. Here we report that retinoid signaling regulates the fate specification of atrial versus ventricular myocytes during cardiac differentiation of hESCs. We found that both Noggin and the panretinoic acid receptor antagonist BMS-189453 (RAi) significantly increased the cardiac differentiation efficiency of hESCs. To investigate retinoid functions, we compared Noggin+RAi-treated cultures with Noggin+RA-treated cultures. Our results showed that the expression levels of the ventricular-specific gene IRX-4 were radically elevated in Noggin+RAi-treated cultures. MLC-2V, another ventricular-specific marker, was expressed in the majority of the cardiomyocytes in Noggin+RAi-treated cultures, hut not in the cardiomyocytes of Noggin+RA-treated cultures. Flow cytometry analysis and electrophysiologicai studies indicated that with 64.7 ± 0.88% (mean ± s.e.m) cardiac differentiation efficiency, 83% of the cardiomyocytes in Noggin+RAi-treated cultures had embryonic ventricular-like action potentials (APs). With 50.7 ± 1.76% cardiac differentiation efficiency, 94% of the cardiomyocytes in Noggin+RA-treated cultures had embryonic atrial-like APs. These results were further confirmed by imaging studies that assessed the patterns and properties of the Ca2+ sparks of the cardiomyocytes from the two cultures. These findings demonstrate that retinoid signaling specifies the atrial versus ventricular differentiation of hESCs. This study also shows that relatively homogeneous embryonic atrial- and ventricular-like myocyte populations can be efficiently derived from hESCs by specifically regulating Noggin

  2. Cardiac remodeling as a consequence of atrial fibrillation: An anatomical study of perfusion-fixed human heart specimens

    Institute of Scientific and Technical Information of China (English)

    Christopher D Rolfes; Stephen A Howard; Ryan P Goff; Paul A Iaizzo

    2011-01-01

    Background Atrial fibrillation(AF)causes a continuum of atrial anatomical remodeling.Methods Using a library of perfusion-fixed human hearts,specimens with AF were compared to controls.During this preliminary assessment study,direct measurements were taken of atrial volume,pulmonary vein(PV)circumference,and left atrial(LA)wall thicknesses.Results Hearts with AF typically had larger atrial volumes,as well as a much larger variation in volume compared to controls(range of 59.6-227.1 mL in AF hearts compared to 65.1-115.9 mL in controls).For all hearts,right PVs were larger than left PVs(mean: 171.4±84.6 mm' for right and 118.2±50.1 mm2 for left P<0.005).LA wall thicknesses ranged from 0.7 mm to 3.1 min for both AF and control hearts.Conclusions Hearts with AF had a large range of sizes which is consistent with the progression of atrial remodeling during AF.The large range of thicknesses will influence the amount of energy needed to create transmural lesions during ablation procedures.

  3. A three-dimensional finite element model of human atrial anatomy: new methods for cubic Hermite meshes with extraordinary vertices.

    Science.gov (United States)

    Gonzales, Matthew J; Sturgeon, Gregory; Krishnamurthy, Adarsh; Hake, Johan; Jonas, René; Stark, Paul; Rappel, Wouter-Jan; Narayan, Sanjiv M; Zhang, Yongjie; Segars, W Paul; McCulloch, Andrew D

    2013-07-01

    High-order cubic Hermite finite elements have been valuable in modeling cardiac geometry, fiber orientations, biomechanics, and electrophysiology, but their use in solving three-dimensional problems has been limited to ventricular models with simple topologies. Here, we utilized a subdivision surface scheme and derived a generalization of the "local-to-global" derivative mapping scheme of cubic Hermite finite elements to construct bicubic and tricubic Hermite models of the human atria with extraordinary vertices from computed tomography images of a patient with atrial fibrillation. To an accuracy of 0.6 mm, we were able to capture the left atrial geometry with only 142 bicubic Hermite finite elements, and the right atrial geometry with only 90. The left and right atrial bicubic Hermite meshes were G1 continuous everywhere except in the one-neighborhood of extraordinary vertices, where the mean dot products of normals at adjacent elements were 0.928 and 0.925. We also constructed two biatrial tricubic Hermite models and defined fiber orientation fields in agreement with diagrammatic data from the literature using only 42 angle parameters. The meshes all have good quality metrics, uniform element sizes, and elements with aspect ratios near unity, and are shared with the public. These new methods will allow for more compact and efficient patient-specific models of human atrial and whole heart physiology. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Septate gallbladder in the laparoscopic era

    Directory of Open Access Journals (Sweden)

    Patel Nitin

    2008-01-01

    Full Text Available The anatomy facing a surgeon during cholecystectomy is challenging as it involves complex relationship between the gallbladder, hepatic artery and extra-hepatic billiary tree. We report a case of septate gall bladder which was successfully treated with laparoscopic cholecystectomy. In this paper, we also discuss the embryology and characteristics of this rare anomaly. Lack of awareness, non-specific symptoms, signs and inadequacy of imaging methods are possible reasons for the reported problem of overlooking of this entity. Complete identification and removal of gallbladder is mandatory, as a remnant may result in recurrence of symptoms or stones.

  5. Doppler echo evaluation of pulmonary venous-left atrial pressure gradients: human and numerical model studies

    Science.gov (United States)

    Firstenberg, M. S.; Greenberg, N. L.; Smedira, N. G.; Prior, D. L.; Scalia, G. M.; Thomas, J. D.; Garcia, M. J.

    2000-01-01

    The simplified Bernoulli equation relates fluid convective energy derived from flow velocities to a pressure gradient and is commonly used in clinical echocardiography to determine pressure differences across stenotic orifices. Its application to pulmonary venous flow has not been described in humans. Twelve patients undergoing cardiac surgery had simultaneous high-fidelity pulmonary venous and left atrial pressure measurements and pulmonary venous pulsed Doppler echocardiography performed. Convective gradients for the systolic (S), diastolic (D), and atrial reversal (AR) phases of pulmonary venous flow were determined using the simplified Bernoulli equation and correlated with measured actual pressure differences. A linear relationship was observed between the convective (y) and actual (x) pressure differences for the S (y = 0.23x + 0.0074, r = 0.82) and D (y = 0.22x + 0.092, r = 0.81) waves, but not for the AR wave (y = 0. 030x + 0.13, r = 0.10). Numerical modeling resulted in similar slopes for the S (y = 0.200x - 0.127, r = 0.97), D (y = 0.247x - 0. 354, r = 0.99), and AR (y = 0.087x - 0.083, r = 0.96) waves. Consistent with numerical modeling, the convective term strongly correlates with but significantly underestimates actual gradient because of large inertial forces.

  6. Mechanisms of arrhythmogenesis related to calcium-driven alternans in a model of human atrial fibrillation

    Science.gov (United States)

    Chang, Kelly C.; Trayanova, Natalia A.

    2016-11-01

    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. We found that elevated propensity to CDA rendered the atria vulnerable to ectopy-induced arrhythmia. It also increased the complexity and persistence of arrhythmias induced by fast pacing, with unstable scroll waves meandering and frequently breaking up to produce multiple wavelets. Our results suggest that calcium-induced electrical instability may increase arrhythmia vulnerability and promote increasing disorganization of arrhythmias in the chronic AF-remodeled atria, thus playing an important role in the progression of the disease.

  7. Study of atrial arrhythmias in a computer model based on magnetic resonance images of human atria

    Science.gov (United States)

    Virag, N.; Jacquemet, V.; Henriquez, C. S.; Zozor, S.; Blanc, O.; Vesin, J.-M.; Pruvot, E.; Kappenberger, L.

    2002-09-01

    The maintenance of multiple wavelets appears to be a consistent feature of atrial fibrillation (AF). In this paper, we investigate possible mechanisms of initiation and perpetuation of multiple wavelets in a computer model of AF. We developed a simplified model of human atria that uses an ionic-based membrane model and whose geometry is derived from a segmented magnetic resonance imaging data set. The three-dimensional surface has a realistic size and includes obstacles corresponding to the location of major vessels and valves, but it does not take into account anisotropy. The main advantage of this approach is its ability to simulate long duration arrhythmias (up to 40 s). Clinically relevant initiation protocols, such as single-site burst pacing, were used. The dynamics of simulated AF were investigated in models with different action potential durations and restitution properties, controlled by the conductance of the slow inward current in a modified Luo-Rudy model. The simulation studies show that (1) single-site burst pacing protocol can be used to induce wave breaks even in tissue with uniform membrane properties, (2) the restitution-based wave breaks in an atrial model with realistic size and conduction velocities are transient, and (3) a significant reduction in action potential duration (even with apparently flat restitution) increases the duration of AF.

  8. Hepatic-intestinal disposal of endogenous human alpha atrial natriuretic factor99-126 in patients with cirrhosis

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik; Bendtsen, Flemming; Schütten, H J

    1990-01-01

    Hepatic-intestinal disposal of endogenous human alpha atrial natriuretic factor99-126 (ANF) was assessed in 13 patients with cirrhosis (six Child-Turcotte class A, five class B, and two class C) and eight control subjects. The Fick principle was applied during hepatic vein catheterization. Arterial...

  9. Hepatic-intestinal disposal of endogenous human alpha atrial natriuretic factor99-126 in patients with cirrhosis

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Bendtsen, F; Schütten, H J

    1990-01-01

    Hepatic-intestinal disposal of endogenous human alpha atrial natriuretic factor99-126 (ANF) was assessed in 13 patients with cirrhosis (six Child-Turcotte class A, five class B, and two class C) and eight control subjects. The Fick principle was applied during hepatic vein catheterization. Arterial...

  10. TASK-1 and TASK-3 may form heterodimers in human atrial cardiomyocytes.

    Science.gov (United States)

    Rinné, Susanne; Kiper, Aytug K; Schlichthörl, Günter; Dittmann, Sven; Netter, Michael F; Limberg, Sven H; Silbernagel, Nicole; Zuzarte, Marylou; Moosdorf, Rainer; Wulf, Hinnerk; Schulze-Bahr, Eric; Rolfes, Caroline; Decher, Niels

    2015-04-01

    TASK-1 channels have emerged as promising drug targets against atrial fibrillation, the most common arrhythmia in the elderly. While TASK-3, the closest relative of TASK-1, was previously not described in cardiac tissue, we found a very prominent expression of TASK-3 in right human auricles. Immunocytochemistry experiments of human right auricular cardiomyocytes showed that TASK-3 is primarily localized at the plasma membrane. Single-channel recordings of right human auricles in the cell-attached mode, using divalent-cation-free solutions, revealed a TASK-1-like channel with a single-channel conductance of about 30pS. While homomeric TASK-3 channels were not found, we observed an intermediate single-channel conductance of about 55pS, possibly reflecting the heteromeric channel formed by TASK-1 and TASK-3. Subsequent experiments with TASK-1/TASK-3 tandem channels or with co-expressed TASK-1 and TASK-3 channels in HEK293 cells or Xenopus oocytes, supported that the 55pS channels observed in right auricles have electrophysiological characteristics of TASK-1/TASK-3 heteromers. In addition, co-expression experiments and single-channel recordings suggest that heteromeric TASK-1/TASK-3 channels have a predominant surface expression and a reduced affinity for TASK-1 blockers. In summary, the evidence for heteromeric TASK-1/TASK-3 channel complexes together with an altered pharmacologic response to TASK-1 blockers in vitro is likely to have further impact for studies isolating ITASK-1 from cardiomyocytes and for the development of drugs specifically targeting TASK-1 in atrial fibrillation treatment.

  11. Successful term delivery of spontaneous twin pregnancy in a woman with bicorporeal septate uterus: A case report.

    Science.gov (United States)

    Li, Yanfang; Yang, Lilin; Tian, Yuanyuan; Li, Daocheng; Luo, Songping

    2016-08-01

    Herein, we report the first case of successful term delivery of twins in a patient with bicorporeal septate uterus via natural conception. The patient had been diagnosed with complete septate, didelphys and bicornuate uterus during different phases of her three pregnancies. Based on follow-up data at six weeks and then six months post-partum of the last pregnancy, we found that the abnormalities presented in our case did not fit the criteria of any categories following American Fertility Society and European Society of Human Reproduction and Embryology-European Society for Gynaecological Endoscopy classification systems. After comprehensive review of the uterine morphologic characteristics, embryology and pregnancy outcome, we considered 'bicorporeal septate uterus' the most appropriate diagnosis. This case emphasized the atypical changes of uterine shape as twin pregnancy advances and its influence on productive performance and pregnancy outcome in uterine malformation. It also raised concern regarding the usability and comprehensiveness of the two most popular classification systems.

  12. Chymase-dependent generation of angiotensin II from angiotensin-(1-12 in human atrial tissue.

    Directory of Open Access Journals (Sweden)

    Sarfaraz Ahmad

    Full Text Available Since angiotensin-(1-12 [Ang-(1-12] is a non-renin dependent alternate precursor for the generation of cardiac Ang peptides in rat tissue, we investigated the metabolism of Ang-(1-12 by plasma membranes (PM isolated from human atrial appendage tissue from nine patients undergoing cardiac surgery for primary control of atrial fibrillation (MAZE surgical procedure. PM was incubated with highly purified ¹²⁵I-Ang-(1-12 at 37°C for 1 h with or without renin-angiotensin system (RAS inhibitors [lisinopril for angiotensin converting enzyme (ACE, SCH39370 for neprilysin (NEP, MLN-4760 for ACE2 and chymostatin for chymase; 50 µM each]. ¹²⁵I-Ang peptide fractions were identified by HPLC coupled to an inline γ-detector. In the absence of all RAS inhibitor, ¹²⁵I-Ang-(1-12 was converted into Ang I (2±2%, Ang II (69±21%, Ang-(1-7 (5±2%, and Ang-(1-4 (2±1%. In the absence of all RAS inhibitor, only 22±10% of ¹²⁵I-Ang-(1-12 was unmetabolized, whereas, in the presence of the all RAS inhibitors, 98±7% of ¹²⁵I-Ang-(1-12 remained intact. The relative contribution of selective inhibition of ACE and chymase enzyme showed that ¹²⁵I-Ang-(1-12 was primarily converted into Ang II (65±18% by chymase while its hydrolysis into Ang II by ACE was significantly lower or undetectable. The activity of individual enzyme was calculated based on the amount of Ang II formation. These results showed very high chymase-mediated Ang II formation (28±3.1 fmol × min⁻¹ × mg⁻¹, n = 9 from ¹²⁵I-Ang-(1-12 and very low or undetectable Ang II formation by ACE (1.1±0.2 fmol×min⁻¹ × mg⁻¹. Paralleling these findings, these tissues showed significant content of chymase protein that by immunocytochemistry were primarily localized in atrial cardiac myocytes. In conclusion, we demonstrate for the first time in human cardiac tissue a dominant role of cardiac chymase in the formation of Ang II from Ang-(1-12.

  13. Characterization of Mg2+-regulated TRPM7-like current in human atrial myocytes

    Directory of Open Access Journals (Sweden)

    Macianskiene Regina

    2012-08-01

    Full Text Available Abstract Background TRPM7 (Transient Receptor Potential of the Melastatin subfamily proteins are highly expressed in the heart, however, electrophysiological studies, demonstrating and characterizing these channels in human cardiomyocytes, are missing. Methods We have used the patch clamp technique to characterize the biophysical properties of TRPM7 channel in human myocytes isolated from right atria small chunks obtained from 116 patients in sinus rhythm during coronary artery and valvular surgery. Under whole-cell voltage-clamp, with Ca2+ and K+ channels blocked, currents were generated by symmetrical voltage ramp commands to potentials between -120 and +80 mV, from a holding potential of -80 mV. Results We demonstrate that activated native current has dual control by intracellular Mg2+ (free-Mg2+ or ATP-bound form, and shows up- or down-regulation by its low or high levels, respectively, displaying outward rectification in physiological extracellular medium. High extracellular Mg2+ and Ca2+ block the outward current, while Gd3+, SpM4+, 2-APB, and carvacrol inhibit both (inward and outward currents. Besides, divalents also permeate the channel, and the efficacy sequence, at 20 mM, was Mg2+>Ni2+>Ca2+>Ba2+>Cd2+ for decreasing outward and Ni2+>Mg2+>Ba2+≥Ca2+>Cd2+ for increasing inward currents. The defined current bears many characteristics of heterologously expressed or native TRPM7 current, and allowed us to propose that current under study is TRPM7-like. However, the time of beginning and time to peak as well steady state magnitude (range from 1.21 to 11.63 pA/pF, ncells/patients = 136/77 of induced TRPM7-like current in atrial myocytes from different patients showed a large variability, while from the same sample of human atria all these parameters were very homogenous. We present new information that TRPM7-like current in human myocytes is less sensitive to Mg2+. In addition, in some myocytes (from 24 out of 77 patients that current

  14. A new algorithm to diagnose atrial ectopic origin from multi lead ECG systems--insights from 3D virtual human atria and torso.

    Science.gov (United States)

    Alday, Erick A Perez; Colman, Michael A; Langley, Philip; Butters, Timothy D; Higham, Jonathan; Workman, Antony J; Hancox, Jules C; Zhang, Henggui

    2015-01-01

    Rapid atrial arrhythmias such as atrial fibrillation (AF) predispose to ventricular arrhythmias, sudden cardiac death and stroke. Identifying the origin of atrial ectopic activity from the electrocardiogram (ECG) can help to diagnose the early onset of AF in a cost-effective manner. The complex and rapid atrial electrical activity during AF makes it difficult to obtain detailed information on atrial activation using the standard 12-lead ECG alone. Compared to conventional 12-lead ECG, more detailed ECG lead configurations may provide further information about spatio-temporal dynamics of the body surface potential (BSP) during atrial excitation. We apply a recently developed 3D human atrial model to simulate electrical activity during normal sinus rhythm and ectopic pacing. The atrial model is placed into a newly developed torso model which considers the presence of the lungs, liver and spinal cord. A boundary element method is used to compute the BSP resulting from atrial excitation. Elements of the torso mesh corresponding to the locations of the placement of the electrodes in the standard 12-lead and a more detailed 64-lead ECG configuration were selected. The ectopic focal activity was simulated at various origins across all the different regions of the atria. Simulated BSP maps during normal atrial excitation (i.e. sinoatrial node excitation) were compared to those observed experimentally (obtained from the 64-lead ECG system), showing a strong agreement between the evolution in time of the simulated and experimental data in the P-wave morphology of the ECG and dipole evolution. An algorithm to obtain the location of the stimulus from a 64-lead ECG system was developed. The algorithm presented had a success rate of 93%, meaning that it correctly identified the origin of atrial focus in 75/80 simulations, and involved a general approach relevant to any multi-lead ECG system. This represents a significant improvement over previously developed algorithms.

  15. Atrial natriuretic peptide regulates lipid mobilization and oxygen consumption in human adipocytes by activating AMPK

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Sandra C. [Translational Sciences - Translational Medicine, Novartis Institutes for Biomedical Research, Inc., 220 Massachusetts Avenue, Cambridge, MA 02139 (United States); Chau, Mary D.L.; Yang, Qing [Cardiovascular and Metabolism Disease Area, Novartis Institutes for Biomedical Research, Inc., 100 Technology Square, Cambridge, MA 02139 (United States); Gauthier, Marie-Soleil [Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02140 (United States); Clairmont, Kevin B.; Wu, Zhidan; Gromada, Jesper [Cardiovascular and Metabolism Disease Area, Novartis Institutes for Biomedical Research, Inc., 100 Technology Square, Cambridge, MA 02139 (United States); Dole, William P., E-mail: bill.dole@novartis.com [Translational Sciences - Translational Medicine, Novartis Institutes for Biomedical Research, Inc., 220 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2011-07-08

    Highlights: {yields} Treatment of differentiated human adipocytes with atrial natriuretic peptide (ANP) increased lipolysis and oxygen consumption by activating AMP-activated protein kinase (AMPK). {yields} ANP stimulated lipid mobilization by selective activation of the alpha2 subunit of AMPK and increased energy utilization through activation of both the alpha1 and alpha2 subunits of AMPK. {yields} ANP enhanced adipocyte mitochondrial oxidative capacity as evidenced by induction of oxidative mitochondrial genes and increase in oxygen consumption. {yields} Exposure of human adipocytes to fatty acids and (TNF{alpha}) induced insulin resistance and decreased expression of mitochondrial genes which was restored to normal by ANP. -- Abstract: Atrial natriuretic peptide (ANP) has been shown to regulate lipid and carbohydrate metabolism providing a possible link between cardiovascular function and metabolism by mediating the switch from carbohydrate to lipid mobilization and oxidation. ANP exerts a potent lipolytic effect via cGMP-dependent protein kinase (cGK)-I mediated-stimulation of AMP-activated protein kinase (AMPK). Activation of the ANP/cGK signaling cascade also promotes muscle mitochondrial biogenesis and fat oxidation. Here we demonstrate that ANP regulates lipid metabolism and oxygen utilization in differentiated human adipocytes by activating the alpha2 subunit of AMPK. ANP treatment increased lipolysis by seven fold and oxygen consumption by two fold, both of which were attenuated by inhibition of AMPK activity. ANP-induced lipolysis was shown to be mediated by the alpha2 subunit of AMPK as introduction of dominant-negative alpha2 subunit of AMPK attenuated ANP effects on lipolysis. ANP-induced activation of AMPK enhanced mitochondrial oxidative capacity as evidenced by a two fold increase in oxygen consumption and induction of mitochondrial genes, including carnitine palmitoyltransferase 1A (CPT1a) by 1.4-fold, cytochrome C (CytC) by 1.3-fold, and

  16. Activation of proteolysis by calpains and structural changes in human paroxysmal and persistent atrial fibrillation

    NARCIS (Netherlands)

    Brundel, BJJM; Ausma, J; van Gelder, IC; Van Der Want, JJL; van Gilst, WH; Crijns, HJGM; Henning, RH

    2002-01-01

    Objective: Atrial fibrillation (AF) is accompanied by electrical. structural and ion-channel protein remodeling. We tested if proteolysis by calpain and proteasome is activated during AF. and studied the relation with the remodeling processes. Methods: Right atrial appendages were obtained from pati

  17. Dark septate endophyte decreases stress on rice plants.

    Science.gov (United States)

    Santos, Silvana Gomes Dos; Silva, Paula Renata Alves da; Garcia, Andres Calderin; Zilli, Jerri Édson; Berbara, Ricardo Luis Louro

    2016-12-27

    Abiotic stress is one of the major limiting factors for plant development and productivity, which makes it important to identify microorganisms capable of increasing plant tolerance to stress. Dark septate endophytes can be symbionts of plants. In the present study, we evaluated the ability of dark septate endophytes isolates to reduce the effects of water stress in the rice varieties Nipponbare and Piauí. The experiments were performed under gnotobiotic conditions, and the water stress was induced with PEG. Four dark septate endophytes were isolated from the roots of wild rice (Oryza glumaepatula) collected from the Brazilian Amazon. Plant height as well as shoot and root fresh and dry matter were measured. Leaf protein concentrations and antioxidant enzyme activity were also estimated. The dark septate endophytes were grown in vitro in Petri dishes containing culture medium; they exhibited different levels of tolerance to salinity and water stress. The two rice varieties tested responded differently to inoculation with dark septate endophytes. Endophytes promoted rice plant growth both in the presence and in the absence of a water deficit. Decreased oxidative stress in plants in response to inoculation was observed in nearly all inoculated treatments, as indicated by the decrease in antioxidant enzyme activity. Dark septate endophytes fungi were shown to increase the tolerance of rice plants to stress caused by water deficiency.

  18. Constriction and septation during cell division in caulobacters.

    Science.gov (United States)

    Poindexter, J S; Hagenzieker, J G

    1981-07-01

    Morphogenesis of the division site in caulobacters had been described as constrictive in Caulobacter spp. and septate in Asticcacaulis excentricus. However, subsequent studies of other gram-negative genera had implied that constrictive division was an artefact resulting from inadequate preservation of septa; exploration of alternatives to osmium fixation, particularly with aldehydes, was recommended. In this study, the appearance of sectioned division sites was reinvestigated in caulobacter cells prepared by 20 different procedures varying with respect to fixation agents, media, schedules, and temperatures, to dehydrating agents, and to embedding resins. Three types of division site morphogenesis were observed: constriction in C. bacteroides and C. crescentus, partial septation in C. leidyi, and complete, undivided septation in A. excentricus and A. biprosthecum. The anatomy of the division site depended on the bacterial strain, not on the method of preparation of the cells for sectioning. These studies confirm the earlier observations on osmium-fixed caulobacter cells and lead to the general conclusion that gram-negative bacteria with tapered poles probably divide by constriction, whereas septation results in blunt cell poles. A pattern of spiral, rather than circular, insertion of new envelope subunits at the cell equator is proposed as a basic developmental difference between constrictive and septate fission in gram-negative bacteria. Since caulobacter prosthecae can develop as extensions of tapered poles formed by constriction, whereas subpolar or lateral prosthecae occur in species with blunt poles resulting from septation, the site of formation of a thick septum appears unsuitable as a site of subsequent envelope outgrowth.

  19. Atrial natriuretic peptide contributes to physiological control of lipid mobilization in humans.

    Science.gov (United States)

    Moro, Cedric; Crampes, Francois; Sengenes, Coralie; De Glisezinski, Isabelle; Galitzky, Jean; Thalamas, Claire; Lafontan, Max; Berlan, Michel

    2004-05-01

    In humans, lipid mobilization is considered to depend mainly on sympathetic nervous system activation and catecholamine action. A contribution of ANP was hypothesized because we have previously shown that atrial natriuretic peptide (ANP) is a lipolytic agent on isolated human fat cells. Control of lipid-mobilizing mechanisms was investigated using in situ microdialysis in subcutaneous adipose tissue (SCAT) in healthy young men during two successive exercise bouts performed at 35% and 60% peak oxygen consumption (VO2max) after placebo or acute oral tertatolol (nonselective beta-antagonist) treatment. In placebo-treated subjects, infusion of propranolol in the probe (100 micromol/l) only partially reduced (40%) the increment in extracellular glycerol concentration (EGC) promoted by exercise. Moreover, oral beta-adrenergic receptor blockade did not prevent exercise-induced lipid mobilization in SCAT while exerting fat cell beta-adrenergic receptor blockade. Exercise-induced increase in plasma ANP was potently amplified by oral tertatolol. A positive correlation was found between EGC and plasma ANP levels but also between extracellular cGMP (i.e., index of ANP-mediated lipolysis) and EGC. Thus, we demonstrate that exercise-induced lipid mobilization resistant to local propranolol and lipid-mobilizing action observed under oral beta-blockade is related to the action of ANP. Oral beta-adrenergic receptor blockade, which potentiates exercise-induced ANP release by the heart, may contribute to lipid mobilization in SCAT. The potential relevance of an ANP-related lipid-mobilizing pathway is discussed.

  20. Atrial fibrillation

    African Journals Online (AJOL)

    ABEOLUGBENGAS

    patients with atrial fibrillation managed in a referral hospital in Port Harcourt, southern Nigeria. ... treatment despite all the patients having moderate to high risk of stroke ... Keywords: Atrial fibrillation, thrombosis, CHADS2 Score, stroke risk, ...

  1. A 2D Electromechanical Model of Human Atrial Tissue Using the Discrete Element Method.

    Science.gov (United States)

    Brocklehurst, Paul; Adeniran, Ismail; Yang, Dongmin; Sheng, Yong; Zhang, Henggui; Ye, Jianqiao

    2015-01-01

    Cardiac tissue is a syncytium of coupled cells with pronounced intrinsic discrete nature. Previous models of cardiac electromechanics often ignore such discrete properties and treat cardiac tissue as a continuous medium, which has fundamental limitations. In the present study, we introduce a 2D electromechanical model for human atrial tissue based on the discrete element method (DEM). In the model, single-cell dynamics are governed by strongly coupling the electrophysiological model of Courtemanche et al. to the myofilament model of Rice et al. with two-way feedbacks. Each cell is treated as a viscoelastic body, which is physically represented by a clump of nine particles. Cell aggregations are arranged so that the anisotropic nature of cardiac tissue due to fibre orientations can be modelled. Each cell is electrically coupled to neighbouring cells, allowing excitation waves to propagate through the tissue. Cell-to-cell mechanical interactions are modelled using a linear contact bond model in DEM. By coupling cardiac electrophysiology with mechanics via the intracellular Ca(2+) concentration, the DEM model successfully simulates the conduction of cardiac electrical waves and the tissue's corresponding mechanical contractions. The developed DEM model is numerically stable and provides a powerful method for studying the electromechanical coupling problem in the heart.

  2. Feasibility of In-Vivo Simulation of Acute Hemodynamics in Human Atrial Fibrillation

    Science.gov (United States)

    Sramko, Marek; Wichterle, Dan; Kautzner, Josef

    2016-01-01

    This study evaluated hemodynamic feasibility and reproducibility of a new method for in vivo simulation of human atrial fibrillation (AF). The method was tested during sinus rhythm in 10 patients undergoing catheter ablation for AF. A simple electronic device was assembled that allowed triggering a cardiac stimulator by predefined series of RR intervals. Irregular RR interval sequences with a mean heart rate of 90/min and 130/min were obtained from ECG recordings of another patients with AF. Simultaneous atrioventricular pacing was delivered by catheters placed inside the coronary sinus and at the His bundle region. Hemodynamic effect of the simulated AF was assessed by invasive measurement of the left ventricular (LV) pressure, dP/dt, and Tau. Compared to regular pacing at the same mean heart rate, the simulated AF significantly impaired the LV both systolic and diastolic function. Repeated AF pacing in the same patients generated similar LV hemodynamics. The proposed method provides a realistic and reproducible in-vivo model of AF. It can be exploited for investigation of the hemodynamic consequences of AF in various patient populations. PMID:27764240

  3. Innervation of the sinu-atrial node and neighbouring regions in two human embryos.

    Science.gov (United States)

    Orts Llorca, F; Domenech Mateu, J M; Puerta Fonolla, J

    1979-03-01

    In human embryos of 20 to 23 mm (36 to 40 days) it is possible to identify on the right side a nerve that we may call the sinusal, which originates by several roots from the nervus vagus dexter (Figs. 1A, B, D), descending through the right ventrolateral face of the primary trachea and right bronchus (Fig. 2, arrows). Beaded in appearance, it gives a fine anastomotic branch which, passing in front of the arteria pulmonalis dextra, passes to the left side (Figs. 2B, C, D; AN). At this level it gives the large branch for the nodus sinoatrialis which, penetrating through the wall of the superior vena cava, provides a rich innervation for the nodus sinoatrialis which is already in an advanced stage of differentiation (Fig. 3, 2; Cy, D, AN). Afterwards it gives fine branches which, following the atrial fold, are distributed throughout the posterior face of the atrium dextrum (Fig. 3). It increases in diameter and, passing through the angle formed by the right pulmonary veins with the atrium dextrum, reaches the intrapericardial portion of the inferior vena cava in the vicinity of its outlet from the atrium (Fig. 3, arrows). The whole innervation is parasympathetic at the stages studied.

  4. Bmp7 functions via a polarity mechanism to promote cloacal septation.

    Directory of Open Access Journals (Sweden)

    Kun Xu

    Full Text Available BACKGROUND: During normal development in human and other placental mammals, the embryonic cloacal cavity separates along the axial longitudinal plane to give rise to the urethral system, ventrally, and the rectum, dorsally. Defects in cloacal development are very common and present clinically as a rectourethral fistula in about 1 in 5,000 live human births. Yet, the cellular mechanisms of cloacal septation remain poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: We previously detected Bone morphogenetic protein 7 (Bmp7 expression in the urorectal mesenchyme (URM, and have shown that loss of Bmp7 function results in the arrest of cloacal septation. Here, we present evidence that cloacal partitioning is driven by Bmp7 signaling in the cloacal endoderm. We performed TUNEL and immunofluorescent analysis on cloacal sections from Bmp7 null and control littermate embryos. We found that loss of Bmp7 results in a dramatic decrease in the endoderm survival and a delay in differentiation. We used immunological methods to show that Bmp7 functions by activating the c-Jun N-terminal kinase (JNK pathway. We carried out confocal and 3D imaging analysis of mitotic chromosome bundles to show that during normal septation cells in the cloacal endoderm divide predominantly in the apical-basal direction. Loss of Bmp7/JNK signaling results in randomization of mitotic angles in the cloacal endoderm. We also conducted immunohistochemical analysis of human fetal sections to show that BMP/phospho-SMAD and JNK pathways function in the human cloacal region similar as in the mouse. CONCLUSION/SIGNIFICANCE: Our results strongly indicate that Bmp7/JNK signaling regulates remodeling of the cloacal endoderm resulting in a topological separation of the urinary and digestive systems. Our study points to the importance of Bmp and JNK signaling in cloacal development and rectourethral malformations.

  5. Up-regulation of miR-31 in human atrial fibrillation begets the arrhythmia by depleting dystrophin and neuronal nitric oxide synthase

    Science.gov (United States)

    Carnicer, Ricardo; Recalde, Alice; Muszkiewicz, Anna; Jayaram, Raja; Carena, Maria Cristina; Wijesurendra, Rohan; Stefanini, Matilde; Surdo, Nicoletta C.; Lomas, Oliver; Ratnatunga, Chandana; Sayeed, Rana; Krasopoulos, George; Rajakumar, Timothy; Bueno-Orovio, Alfonso; Verheule, Sander; Fulga, Tudor A.; Rodriguez, Blanca; Schotten, Ulrich

    2016-01-01

    Atrial fibrillation (AF) is a growing public health burden, and its treatment remains a challenge. AF leads to electrical remodeling of the atria, which in turn promotes AF maintenance and resistance to treatment. Although remodeling has long been a therapeutic target in AF, its causes remain poorly understood. We show that atrial-specific up-regulation of microRNA-31 (miR-31) in goat and human AF depletes neuronal nitric oxide synthase (nNOS) by accelerating mRNA decay and alters nNOS subcellular localization by repressing dystrophin translation. By shortening action potential duration and abolishing rate-dependent adaptation of the action potential duration, miR-31 overexpression and/or disruption of nNOS signaling recapitulates features of AF-induced remodeling and significantly increases AF inducibility in mice in vivo. By contrast, silencing miR-31 in atrial myocytes from patients with AF restores dystrophin and nNOS and normalizes action potential duration and its rate dependency. These findings identify atrial-specific up-regulation of miR-31 in human AF as a key mechanism causing atrial dystrophin and nNOS depletion, which in turn contributes to the atrial phenotype begetting this arrhythmia. miR-31 may therefore represent a potential therapeutic target in AF. PMID:27225184

  6. Arrhythmias, elicited by catecholamines and serotonin, vanish in human chronic atrial fibrillation.

    Science.gov (United States)

    Christ, Torsten; Rozmaritsa, Nadiia; Engel, Andreas; Berk, Emanuel; Knaut, Michael; Metzner, Katharina; Canteras, Manuel; Ravens, Ursula; Kaumann, Alberto

    2014-07-29

    Atrial fibrillation (AF) is the most common heart rhythm disorder. Transient postoperative AF can be elicited by high sympathetic nervous system activity. Catecholamines and serotonin cause arrhythmias in atrial trabeculae from patients with sinus rhythm (SR), but whether these arrhythmias occur in patients with chronic AF is unknown. We compared the incidence of arrhythmic contractions caused by norepinephrine, epinephrine, serotonin, and forskolin in atrial trabeculae from patients with SR and patients with AF. In the patients with AF, arrhythmias were markedly reduced for the agonists and abolished for forskolin, whereas maximum inotropic responses were markedly blunted only for serotonin. Serotonin and forskolin produced spontaneous diastolic Ca(2+) releases in atrial myocytes from the patients with SR that were abolished or reduced in myocytes from the patients with AF. For matching L-type Ca(2+)-current (ICa,L) responses, serotonin required and produced ∼ 100-fold less cAMP/PKA at the Ca(2+) channel domain compared with the catecholamines and forskolin. Norepinephrine-evoked ICa,L responses were decreased by inhibition of Ca(2+)/calmodulin-dependent kinase II (CaMKII) in myocytes from patients with SR, but not in those from patients with AF. Agonist-evoked phosphorylation by CaMKII at phospholamban (Thr-17), but not of ryanodine2 (Ser-2814), was reduced in trabeculae from patients with AF. The decreased CaMKII activity may contribute to the blunting of agonist-evoked arrhythmias in the atrial myocardium of patients with AF.

  7. Chemical-defined and albumin-free generation of human atrial and ventricular myocytes from human pluripotent stem cells

    Directory of Open Access Journals (Sweden)

    Fei Pei

    2017-03-01

    Full Text Available Most existing culture media for cardiac differentiation of human pluripotent stem cells (hPSCs contain significant amounts of albumin. For clinical transplantation applications of hPSC-derived cardiomyocytes (hPSC-CMs, culturing cells in an albumin containing environment raises the concern of pathogen contamination and immunogenicity to the recipient patients. In addition, batch-to-batch variation of albumin may cause the inconsistent of hPSC cardiac differentiation. Here, we demonstrated that antioxidants l-ascorbic acid, trolox, N-acetyl-l-cysteine (NAC and sodium pyruvate could functionally substitute albumin in the culture medium, and formulated an albumin-free, chemical-defined medium (S12 medium. We showed that S12 medium could support efficient hPSC cardiac differentiation with significantly improved reproducibility, and maintained long-term culture of hPSC-CMs. Furthermore, under chemical-defined and albumin-free conditions, human-induced pluripotent stem cells (hiPSCs were established, and differentiated into highly homogenous atrial and ventricular myocytes in a scalable fashion with normal electrophysiological properties. Finally, we characterized the activity of three typical cardiac ion channels of those cells, and demonstrated that hPSC-derived ventricular cardiomyocytes (hPSC-vCMs were suitable for drug cardiac safety evaluation. In summary, this simplified, chemical-defined and albumin-free culture medium supports efficient generation and maintaining of hPSC-CMs and facilitates both research and clinical applications of these cells.

  8. Prevention of adenosine A2A receptor activation diminishes beat-to-beat alternation in human atrial myocytes.

    Science.gov (United States)

    Molina, Cristina E; Llach, Anna; Herraiz-Martínez, Adela; Tarifa, Carmen; Barriga, Montserrat; Wiegerinck, Rob F; Fernandes, Jacqueline; Cabello, Nuria; Vallmitjana, Alex; Benitéz, Raúl; Montiel, José; Cinca, Juan; Hove-Madsen, Leif

    2016-01-01

    Atrial fibrillation (AF) has been associated with increased spontaneous calcium release from the sarcoplasmic reticulum and linked to increased adenosine A2A receptor (A2AR) expression and activation. Here we tested whether this may favor atrial arrhythmogenesis by promoting beat-to-beat alternation and irregularity. Patch-clamp and confocal calcium imaging was used to measure the beat-to-beat response of the calcium current and transient in human atrial myocytes. Responses were classified as uniform, alternating or irregular and stimulation of Gs-protein coupled receptors decreased the frequency where a uniform response could be maintained from 1.0 ± 0.1 to 0.6 ± 0.1 Hz; p < 0.01 for beta-adrenergic receptors and from 1.4 ± 0.1 to 0.5 ± 0.1 Hz; p < 0.05 for A2ARs. The latter was linked to increased spontaneous calcium release and after-depolarizations. Moreover, A2AR activation increased the fraction of non-uniformly responding cells in HL-1 myocyte cultures from 19 ± 3 to 51 ± 9 %; p < 0.02, and electrical mapping in perfused porcine atria revealed that adenosine induced electrical alternans at longer cycle lengths, doubled the fraction of electrodes showing alternation, and increased the amplitude of alternations. Importantly, protein kinase A inhibition increased the highest frequency where uniform responses could be maintained from 0.84 ± 0.12 to 1.86 ± 0.11 Hz; p < 0.001 and prevention of A2AR-activation with exogenous adenosine deaminase selectively increased the threshold from 0.8 ± 0.1 to 1.2 ± 0.1 Hz; p = 0.001 in myocytes from patients with AF. In conclusion, A2AR-activation promotes beat-to-beat irregularities in the calcium transient in human atrial myocytes, and prevention of A2AR activation may be a novel means to maintain uniform beat-to-beat responses at higher beating frequencies in patients with atrial fibrillation.

  9. Clinical Benefit of Ablating Localized Sources for Human Atrial Fibrillation: The Indiana University FIRM Registry.

    Science.gov (United States)

    Miller, John M; Kalra, Vikas; Das, Mithilesh K; Jain, Rahul; Garlie, Jason B; Brewster, Jordan A; Dandamudi, Gopi

    2017-03-14

    Mounting evidence shows that localized sources maintain atrial fibrillation (AF). However, it is unclear in unselected "real-world" patients if sources drive persistent atrial fibrillation (PeAF), long-standing persistent atrial fibrillation (LPeAF), or paroxysmal atrial fibrillation (PAF); if right atrial sites are important; and what the long-term success of source ablation is. The aim of this study was to analyze the role of rotors and focal sources in a large academic registry of consecutive patients undergoing source mapping for AF. One hundred seventy consecutive patients (mean age 59 ± 12 years, 79% men) with PAF (37%), PeAF (31%), or LPeAF (32%). Of these, 73 (43%) had undergone at least 1 prior ablation attempt (mean 1.9 ± 0.8; range: 1 to 4). Focal impulse and rotor modulation (FIRM) with an endocardial basket catheter was used in all cases. FIRM analysis revealed sources in the right atrium in 85% of patients (1.8 ± 1.3) and in the left atrium in 90% of patients (2.0 ± 1.3). FIRM ablation terminated AF to sinus rhythm or atrial flutter or tachycardia in 59% (PAF), 37% (PeAF), and 19% (LPeAF) of patients, with 15 of 67 terminations due to right atrial ablation. On follow-up, freedom from AF after a single FIRM procedure for the entire series was 95% (PAF), 83% (PeAF), and 82% (LPeAF) at 1 year and freedom from all atrial arrhythmias was 77% (PAF), 75% (PeAF), and 57% (LPeAF). In the Indiana University FIRM registry, FIRM-guided ablation produced high single-procedure success, mostly in patients with nonparoxysmal AF. Data from mapping, acute terminations, and outcomes strongly support the mechanistic role of biatrial rotors and focal sources in maintaining AF in diverse populations. Randomized trials of FIRM-guided ablation and mechanistic studies to determine how rotors form, progress, and regress are needed. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  10. Pulmonary vein and atrial wall pathology in human total anomalous pulmonary venous connection

    NARCIS (Netherlands)

    Douglas, Yvonne L.; Jongbloed, Monique R. M.; den Hartog, Wietske C. E.; Bartelings, Margot M.; Bogers, Ad J. J. C.; Ebels, Tjark; DeRuiter, Marco C.; Gittenberger-de Groot, Adriana C.

    2009-01-01

    Background: Normally, the inside of the left atrial (LA) body and pulmonary veins (PVs) is lined by vessel wall tissue covered by myocardium. In total anomalous pulmonary venous connection (TAPVC), no connection of the PVs with the LA body exists. These veins have an increased incidence of PV

  11. Dark septate endophytic pleosporalean genera from semiarid areas

    NARCIS (Netherlands)

    Knapp, D.G.; Kovács, G.M.; Zajta, E.; Groenwald, J.Z.; Crous, P.W.

    2015-01-01

    Dark septate endophytes (DSE) are distributed worldwide as root-colonising fungi, and frequent in environments with strong abiotic stress. DSE is not a taxon, but constitutes numerous fungal taxa belonging to several orders of Ascomycota. In this study we investigate three unidentified DSE lineages b

  12. Dark septate endophytic pleosporalean genera from semiarid areas

    NARCIS (Netherlands)

    Knapp, D G; Kovács, G M; Zajta, E; Groenewald, J Z; Crous, P W

    2015-01-01

    Dark septate endophytes (DSE) are distributed worldwide as root-colonising fungi, and frequent in environments with strong abiotic stress. DSE is not a taxon, but constitutes numerous fungal taxa belonging to several orders of Ascomycota. In this study we investigate three unidentified DSE lineages

  13. Atrial Electrogram Fractionation Distribution before and after Pulmonary Vein Isolation in Human Persistent Atrial Fibrillation—A Retrospective Multivariate Statistical Analysis

    Science.gov (United States)

    Almeida, Tiago P.; Chu, Gavin S.; Li, Xin; Dastagir, Nawshin; Tuan, Jiun H.; Stafford, Peter J.; Schlindwein, Fernando S.; Ng, G. André

    2017-01-01

    Purpose: Complex fractionated atrial electrograms (CFAE)-guided ablation after pulmonary vein isolation (PVI) has been used for persistent atrial fibrillation (persAF) therapy. This strategy has shown suboptimal outcomes due to, among other factors, undetected changes in the atrial tissue following PVI. In the present work, we investigate CFAE distribution before and after PVI in patients with persAF using a multivariate statistical model. Methods: 207 pairs of atrial electrograms (AEGs) were collected before and after PVI respectively, from corresponding LA regions in 18 persAF patients. Twelve attributes were measured from the AEGs, before and after PVI. Statistical models based on multivariate analysis of variance (MANOVA) and linear discriminant analysis (LDA) have been used to characterize the atrial regions and AEGs. Results: PVI significantly reduced CFAEs in the LA (70 vs. 40%; P PVI that remained fractionated after PVI (31% of the collected points); (ii) fractionated that converted to normal (39%); (iii) normal prior to PVI that became fractionated (9%) and; (iv) normal that remained normal (21%). Individually, the attributes failed to distinguish these LA regions, but multivariate statistical models were effective in their discrimination (P PVI, while others are affected by it. Although, traditional methods were unable to identify these different regions, the proposed multivariate statistical model discriminated LA regions resistant to PVI from those affected by it without prior ablation information. PMID:28883795

  14. Atrial Electrogram Fractionation Distribution before and after Pulmonary Vein Isolation in Human Persistent Atrial Fibrillation-A Retrospective Multivariate Statistical Analysis.

    Science.gov (United States)

    Almeida, Tiago P; Chu, Gavin S; Li, Xin; Dastagir, Nawshin; Tuan, Jiun H; Stafford, Peter J; Schlindwein, Fernando S; Ng, G André

    2017-01-01

    Purpose: Complex fractionated atrial electrograms (CFAE)-guided ablation after pulmonary vein isolation (PVI) has been used for persistent atrial fibrillation (persAF) therapy. This strategy has shown suboptimal outcomes due to, among other factors, undetected changes in the atrial tissue following PVI. In the present work, we investigate CFAE distribution before and after PVI in patients with persAF using a multivariate statistical model. Methods: 207 pairs of atrial electrograms (AEGs) were collected before and after PVI respectively, from corresponding LA regions in 18 persAF patients. Twelve attributes were measured from the AEGs, before and after PVI. Statistical models based on multivariate analysis of variance (MANOVA) and linear discriminant analysis (LDA) have been used to characterize the atrial regions and AEGs. Results: PVI significantly reduced CFAEs in the LA (70 vs. 40%; P multivariate statistical models were effective in their discrimination (P multivariate statistical model discriminated LA regions resistant to PVI from those affected by it without prior ablation information.

  15. Recurrence quantification analysis applied to spatiotemporal pattern analysis in high-density mapping of human atrial fibrillation

    NARCIS (Netherlands)

    Zeemering, Stef; Bonizzi, Pietro; Maesen, Bart; Peeters, Ralf; Schotten, Ulrich

    2015-01-01

    Spatiotemporal complexity of atrial fibrillation (AF) patterns is often quantified by annotated intracardiac contact mapping. We introduce a new approach that applies recurrence plot (RP) construction followed by recurrence quantification analysis (RQA) to epicardial atrial electrograms, recorded wi

  16. Prostacyclins have no direct inotropic effect on isolated atrial strips from the normal and pressure-overloaded human right heart

    DEFF Research Database (Denmark)

    Holmboe, Sarah; Andersen, Asger; Vibjerg Jensen, Rebekka

    2017-01-01

    mimetics in the normal and the pressure-overloaded human right atrium. Trabeculae from the right atrium were collected during surgery from chronic thromboembolic pulmonary hypertension (CTEPH) patients with pressure-overloaded right hearts, undergoing pulmonary thromboendarterectomy (n = 10) and from...... to elicit a reference inotropic response. The force of contraction was measured continuously. The expression of prostanoid receptors was explored through quantitative polymerase chain reaction (qPCR). Iloprost, treprostinil, epoprostenol, or MRE-269 did not alter force of contraction in any...... expression of the different prostanoid receptors in the human atrium. In conclusion, prostacyclin mimetics did not increase the force of contraction of human atrial trabeculae from the normal or the pressure-overloaded right heart. These data suggest that prostacyclin mimetics have no direct inotropic...

  17. Maximal heart rate does not limit cardiovascular capacity in healthy humans: insight from right atrial pacing during maximal exercise.

    Science.gov (United States)

    Munch, G D W; Svendsen, J H; Damsgaard, R; Secher, N H; González-Alonso, J; Mortensen, S P

    2014-01-15

    In humans, maximal aerobic power (VO2 max ) is associated with a plateau in cardiac output (Q), but the mechanisms regulating the interplay between maximal heart rate (HRmax) and stroke volume (SV) are unclear. To evaluate the effect of tachycardia and elevations in HRmax on cardiovascular function and capacity during maximal exercise in healthy humans, 12 young male cyclists performed incremental cycling and one-legged knee-extensor exercise (KEE) to exhaustion with and without right atrial pacing to increase HR. During control cycling, Q and leg blood flow increased up to 85% of maximal workload (WLmax) and remained unchanged until exhaustion. SV initially increased, plateaued and then decreased before exhaustion (P rate pressure product and RAP (P heart can be paced to a higher HR than observed during maximal exercise, suggesting that HRmax and myocardial work capacity do not limit VO2 max in healthy individuals. A limited left ventricular filling and possibly altered contractility reduce SV during atrial pacing, whereas a plateau in LVFP appears to restrict Q close to VO2 max .

  18. Excitation-Contraction Coupling between Human Atrial Myocytes with Fibroblasts and Stretch Activated Channel Current: A Simulation Study

    Directory of Open Access Journals (Sweden)

    Heqing Zhan

    2013-01-01

    Full Text Available Myocytes have been regarded as the main objectives in most cardiac modeling studies and attracted a lot of attention. Connective tissue cells, such as fibroblasts (Fbs, also play crucial role in cardiac function. This study proposed an integrated myocyte-Isac-Fb electromechanical model to investigate the effect of Fbs and stretch activated ion channel current (Isac on cardiac electrical excitation conduction and mechanical contraction. At the cellular level, an active Fb model was coupled with a human atrial myocyte electrophysiological model (including Isac and a mechanical model. At the tissue level, electrical excitation conduction was coupled with an elastic mechanical model, in which finite difference method (FDM was used to solve the electrical excitation equations, while finite element method (FEM was used for the mechanics equations. The simulation results showed that Fbs and Isac coupling caused diverse effects on action potential morphology during repolarization, depolarized the resting membrane potential of the human atrial myocyte, slowed down wave propagation, and decreased strains in fibrotic tissue. This preliminary simulation study indicates that Fbs and Isac have important implications for modulating cardiac electromechanical behavior and should be considered in future cardiac modeling studies.

  19. Atrial Electrogram Fractionation Distribution before and after Pulmonary Vein Isolation in Human Persistent Atrial Fibrillation—A Retrospective Multivariate Statistical Analysis

    Directory of Open Access Journals (Sweden)

    Tiago P. Almeida

    2017-08-01

    Full Text Available Purpose: Complex fractionated atrial electrograms (CFAE-guided ablation after pulmonary vein isolation (PVI has been used for persistent atrial fibrillation (persAF therapy. This strategy has shown suboptimal outcomes due to, among other factors, undetected changes in the atrial tissue following PVI. In the present work, we investigate CFAE distribution before and after PVI in patients with persAF using a multivariate statistical model.Methods: 207 pairs of atrial electrograms (AEGs were collected before and after PVI respectively, from corresponding LA regions in 18 persAF patients. Twelve attributes were measured from the AEGs, before and after PVI. Statistical models based on multivariate analysis of variance (MANOVA and linear discriminant analysis (LDA have been used to characterize the atrial regions and AEGs.Results: PVI significantly reduced CFAEs in the LA (70 vs. 40%; P < 0.0001. Four types of LA regions were identified, based on the AEGs characteristics: (i fractionated before PVI that remained fractionated after PVI (31% of the collected points; (ii fractionated that converted to normal (39%; (iii normal prior to PVI that became fractionated (9% and; (iv normal that remained normal (21%. Individually, the attributes failed to distinguish these LA regions, but multivariate statistical models were effective in their discrimination (P < 0.0001.Conclusion: Our results have unveiled that there are LA regions resistant to PVI, while others are affected by it. Although, traditional methods were unable to identify these different regions, the proposed multivariate statistical model discriminated LA regions resistant to PVI from those affected by it without prior ablation information.

  20. Novel Mutations in the Transcriptional Activator Domain of the Human TBX20 in Patients with Atrial Septal Defect

    Directory of Open Access Journals (Sweden)

    Irma Eloisa Monroy-Muñoz

    2015-01-01

    Full Text Available Background. The relevance of TBX20 gene in heart development has been demonstrated in many animal models, but there are few works that try to elucidate the effect of TBX20 mutations in human congenital heart diseases. In these studies, all missense mutations associated with atrial septal defect (ASD were found in the DNA-binding T-box domain, none in the transcriptional activator domain. Methods. We search for TBX20 mutations in a group of patients with ASD or ventricular septal defect (VSD using the High Resolution Melting (HRM method and DNA sequencing. Results. We report three missense mutations (Y309D, T370O, and M395R within the transcriptional activator domain of human TBX20 that were associated with ASD. Conclusions. This is the first association of TBX20 transcriptional activator domain missense mutations with ASD. These findings could have implications for diagnosis, genetic screening, and patient follow-up.

  1. Septated pericarditis associated with Kawasaki disease: a brief case report.

    Science.gov (United States)

    Sonçaği, Arzu; Devrim, Ilker; Karagöz, Tevfik; Dilber, Embiya; Celiker, Alpay; Ozen, Seza; Seçmeer, Gülten

    2007-01-01

    Kawasaki disease (KD) is primarily the systemic vasculitis of childhood that affects mainly the medium-sized arteries, such as the coronary arteries. KD is the leading cause of acquired heart disease, whereas the incidence of rheumatic fever has declined. The most serious complication is coronary artery involvement. Among the children with KD who developed cardiac complications, pericarditis is a rare complication, with an incidence of 0.07%. We report our experience in a 5.5-year-old child with KD complicated with aneurysm of the left anterior descendant coronary artery and septated pericardial effusion, which has not been reported in the literature. The pericardial effusion disappeared very dramatically with intravenous immunoglobulin (IVIG) therapy. We would like to point out that septated pericardial effusion in cases of KD do not need any further therapy other than IVIG and high-dose acetylsalicylic acid.

  2. Atrial distension, arterial pulsation, and vasopressin release during negative pressure breathing in humans

    DEFF Research Database (Denmark)

    Pump, B; Damgaard, M; Gabrielsen, A

    2001-01-01

    in eight healthy males, we tested the hypothesis that with similar increases in LA diameter, suppression of AVP release is dependent on the degree of increase in PP. LA diameter increased similarly during the posture change and negative pressure breathing (-9 to -24 mmHg) from between 30 and 31 +/- 1 to 34......During an antiorthostatic posture change, left atrial (LA) diameter and arterial pulse pressure (PP) increase, and plasma arginine vasopressin (AVP) is suppressed. By comparing the effects of a 15-min posture change from seated to supine with those of 15-min seated negative pressure breathing...... +/- 1 mm (P breathing from 36 +/- 3 to 42 +/- 3 mmHg (P

  3. Atrial distension, arterial pulsation, and vasopressin release during negative pressure breathing in humans

    DEFF Research Database (Denmark)

    Pump, B; Damgaard, M; Gabrielsen, A;

    2001-01-01

    During an antiorthostatic posture change, left atrial (LA) diameter and arterial pulse pressure (PP) increase, and plasma arginine vasopressin (AVP) is suppressed. By comparing the effects of a 15-min posture change from seated to supine with those of 15-min seated negative pressure breathing...... in eight healthy males, we tested the hypothesis that with similar increases in LA diameter, suppression of AVP release is dependent on the degree of increase in PP. LA diameter increased similarly during the posture change and negative pressure breathing (-9 to -24 mmHg) from between 30 and 31 +/- 1 to 34...... +/- 1 mm (P breathing from 36 +/- 3 to 42 +/- 3 mmHg (P

  4. Deletion of the msdS/AfmsdC gene induces abnormal polarity and septation in Aspergillus fumigatus.

    Science.gov (United States)

    Li, Yanjie; Zhang, Lei; Wang, Depeng; Zhou, Hui; Ouyang, Haomiao; Ming, Jia; Jin, Cheng

    2008-07-01

    alpha-Mannosidases play an important role in the processing of mannose-containing glycans in eukaryotes. A deficiency in alpha-mannosidase is lethal in humans and cattle. In contrast to mammals, Saccharomyces cerevisiae does not require the endoplasmic reticulum alpha-mannosidase gene for growth. However, little is known of the consequence of loss of function of class I alpha-mannosidases in filamentous fungi. In this study, the msdS/AfmsdC gene was identified to encode 1,2-alpha-mannosidase MsdS in Aspergillus fumigatus. Soluble MsdS expressed in Escherichia coli was characterized as a typical class I alpha-mannosidase. The msdS gene was deleted by replacement of the msdS gene with a pyrG gene. Although the mutant showed a defect in N-glycan processing, as well as a reduction of cell wall components and a reduced ability of conidiation, it appeared that the rate of hyphal growth was not affected. Morphology analysis revealed abnormal polarity and septation at the stages of germination, hyphal growth and conidiation. Although the mechanism by which the N-glycan processing affects polarity and septation is unclear, our results show that msdS is involved in polarity and septation in A. fumigatus.

  5. Alpha-human atrial natriuretic polypeptide (. cap alpha. -hANP) specific binding sites in bovine adrenal gland

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, K.; Nawata, H.; Kato, K.I.; Ibayashi, H.; Matsuo, H.

    1986-06-13

    The effects of synthetic ..cap alpha..-human atrial natriuretic polypeptide (..cap alpha..-hANP) on steroidogenesis in bovine adrenocortical cells in primary monolayer culture were investigated. ..cap alpha..-hANP did not inhibit basal aldosterone secretion. ..cap alpha..-hANP induced a significant dose-dependent inhibition of basal levels of cortisol and dehydroepiandrosterone (DHEA) secretion and also of aCTH (10/sup -8/M)-stimulated increases in aldosterone, cortisol and DHEA secretion. Visualization of (/sup 125/I) ..cap alpha..-hANP binding sites in bovine adrenal gland by an in vitro autoradiographic technique demonstrated that these sites were highly localized in the adrenal cortex, especially the zona glomerulosa. These results suggest that the adrenal cortex may be a target organ for direct receptor-mediated actions of ..cap alpha..-hANP.

  6. Spatial relationship of organized rotational and focal sources in human atrial fibrillation to autonomic ganglionated plexi.

    Science.gov (United States)

    Baykaner, Tina; Zografos, Theodoros A; Zaman, Junaid A B; Pantos, Ioannis; Alhusseini, Mahmood; Navara, Rachita; Krummen, David E; Narayan, Sanjiv M; Katritsis, Demosthenes G

    2017-08-01

    One approach to improve ablation for atrial fibrillation (AF) is to focus on physiological targets including focal or rotational sources or ganglionic plexi (GP). However, the spatial relationship between these potential mechanisms has never been studied. We tested the hypothesis that rotors and focal sources for AF may co-localize with ganglionated plexi (GP). We prospectively identified locations of AF rotors and focal sources, and correlated these to GP sites in 97 consecutive patients (age 59.9±11.4, 73% persistent AF). AF was recorded with 64-pole catheters with activation/phase mapping, and related to anatomic GP sites on electroanatomic maps. AF sources arose in 96/97 (99%) patients for 2.6±1.4 sources per patient (left atrium: 1.7±0.9 right atrium: 1.1±0.8), each with an area of 2-3cm(2). On area analyses, the probability of an AF source randomly overlapping a GP area was 26%. Left atrial sources were seen in 94 (97%) patients, in whom ≥1 source co-localized with GP in 75 patients (80%; psources were more likely to colocalize with left vs right GPs (p65, diabetes; psources in the left atrium often colocalize with regions of autonomic innervation. Studies should define if the role of AF sources differs by their anatomical location. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Seasonality of arbuscular mycorrhizal symbiosis and dark septate endophytes in a grassland site in southwest China.

    Science.gov (United States)

    Lingfei, Li; Anna, Yang; Zhiwei, Zhao

    2005-11-01

    Arbuscular mycorrhizal and dark septate endophytic fungal colonization in a grassland in Kunming, southwest China, was investigated monthly over one year. All plant roots surveyed were co-colonized by arbuscular mycorrhizal and dark septate endophytic fungi in this grassland. Both arbuscular mycorrhizal and dark septate endophytic fungal colonization fluctuated significantly throughout the year, and their seasonal patterns were different in each plant species. The relationships between environmental (climatic and edaphic) factors and fungal colonization were also studied. Correlation analysis demonstrated that arbuscular mycorrhizal colonization was significantly correlative with environmental factors (rainfall, sunlight hours, soil P, etc.), but dark septate endophytic fungal colonization was only correlative with relative humidity and sunlight hours.

  8. The Cardiac TBX5 Interactome Reveals a Chromatin Remodeling Network Essential for Cardiac Septation.

    Science.gov (United States)

    Waldron, Lauren; Steimle, Jeffrey D; Greco, Todd M; Gomez, Nicholas C; Dorr, Kerry M; Kweon, Junghun; Temple, Brenda; Yang, Xinan Holly; Wilczewski, Caralynn M; Davis, Ian J; Cristea, Ileana M; Moskowitz, Ivan P; Conlon, Frank L

    2016-02-08

    Human mutations in the cardiac transcription factor gene TBX5 cause congenital heart disease (CHD), although the underlying mechanism is unknown. We report characterization of the endogenous TBX5 cardiac interactome and demonstrate that TBX5, long considered a transcriptional activator, interacts biochemically and genetically with the nucleosome remodeling and deacetylase (NuRD) repressor complex. Incompatible gene programs are repressed by TBX5 in the developing heart. CHD mis-sense mutations that disrupt the TBX5-NuRD interaction cause depression of a subset of repressed genes. Furthermore, the TBX5-NuRD interaction is required for heart development. Phylogenetic analysis showed that the TBX5-NuRD interaction domain evolved during early diversification of vertebrates, simultaneous with the evolution of cardiac septation. Collectively, this work defines a TBX5-NuRD interaction essential to cardiac development and the evolution of the mammalian heart, and when altered may contribute to human CHD.

  9. Arbuscular mycorrhizal and dark septate endophyte associations of medicinal plants

    OpenAIRE

    Szymon Zubek; Janusz Błaszkowski; Piotr Mleczko

    2011-01-01

    Arbuscular mycorrhizal fungi (AMF) and dark septate endophyte (DSE) associations were studied in 36 medicinal plant species from 33 genera and 17 families, collected from the Botanical Garden of the Jagiellonian University in Kraków. Arbuscular mycorrhiza (AM) was found in 34 species (94%); 26 were of the Arum-type, 4 – Paris and 4 taxa revealed intermediate morpho­logy. The abundance of AMF hyphae in roots varied with particular species, ranging from 2.5% (Helianthus tuberosus) to 77.9% (Con...

  10. Unruptured Basilar Tip Aneurysm with Internal Septation: Coiling Implications?

    Directory of Open Access Journals (Sweden)

    Ayman Khalil

    2016-01-01

    Full Text Available An internal septum within a basilar artery aneurysm is an infrequent anomaly and is very rarely reported in the literature. We report a 62-year-old lady that was incidentally diagnosed with basilar tip aneurysm. Further imaging with magnetic resonance imaging (MRI revealed internal septation within this aneurysm which was later confirmed with digital subtraction angiography (DSA. She underwent coil embolisation, which involved technical manipulation of the microcatheter and the balloon to enable coiling of each separate aneurysm compartment. We present this case to illustrate the effect of this anatomical variation on the selection of endovascular treatment strategy.

  11. First-trimester septated cystic hygroma and cavum velum interpositum cyst.

    Science.gov (United States)

    Sherer, David M; Dalloul, Mudar; Miller, Michelle J; Kheyman, Mila; Zinn, Harry L; Abulafia, Ovadia

    2011-07-01

    First-trimester septated cystic hygroma, frequently noted during general obstetric first-trimester screening, is strongly associated with fetal aneuploidy and structural anomalies and is considered an ominous finding. We present the case of a fetus with a first-trimester septated cystic hygroma and cavum velum interpositum cyst.

  12. Atrial fibrillation

    DEFF Research Database (Denmark)

    Lip, Gregory Y H; Fauchier, Laurent; Freedman, Saul B;

    2016-01-01

    Atrial fibrillation (AF) is the most common sustained cardiac rhythm disorder, and increases in prevalence with increasing age and the number of cardiovascular comorbidities. AF is characterized by a rapid and irregular heartbeat that can be asymptomatic or lead to symptoms such as palpitations...

  13. Atrial fibrillation

    DEFF Research Database (Denmark)

    Olesen, Morten S; Nielsen, Morten W; Haunsø, Stig;

    2014-01-01

    Atrial fibrillation (AF) is the most common cardiac arrhythmia affecting 1-2% of the general population. A number of studies have demonstrated that AF, and in particular lone AF, has a substantial genetic component. Monogenic mutations in lone and familial AF, although rare, have been recognized...

  14. Receptors for atrial natriuretic peptide (ANP) and regulation of thyroglobulin secretion by ANP in human thyroid cells

    Energy Technology Data Exchange (ETDEWEB)

    Sellitti, D.F.; Tseng, Y.C.L.; Wartofsky, L. (Uniformed Services Univ. of the Health Sciences, Bethesda, MD (USA) Walter Reed Army Medical Center, Washington, DC (USA))

    1989-01-01

    Specific binding sites for atrial natriuretic peptide (ANP) were identified and characterized in primary cultures of human thyroid cells. Saturation analysis using ({sup 125}I) {alpha} rat (1-28) ANP as the ligand showed a single class of high affinity binding which was inhibited by atriopeptin I and the {alpha} -human form of ANP, but not by a C-terminal fragment (13-28) of the peptide. The number of ANP binding sites in these cultures was not altered by the thyroid hormone concentration of the medium. In a dose-response experiment, thyroglobulin secretion was significantly reduced in the presence of 0.01 nM ANP and was maximally reduced with 10 nM ANP. Cyclic GMP production was increased threefold in the presence of 100 nM ANP, but was unchanged with lower doses of the peptides. The finding of receptors in thyroid follicular cells suggests a hitherto unrecognized role of ANP in the thyroid gland.

  15. Effects of dark septate endophytes on tomato plant performance.

    Science.gov (United States)

    Andrade-Linares, Diana Rocio; Grosch, Rita; Restrepo, Silvia; Krumbein, Angelika; Franken, Philipp

    2011-07-01

    Non-mycorrhizal fungal root endophytes can be found in all natural and cultivated ecosystems, but little is known about their impact on plant performance. The impact of three mitosporic dark septate endophytes (DSE48, DSE49 and Leptodontidium orchidicola) on tomato plant characteristics was studied. Their effects on root and shoot growth, their influence on fruit yield and fruit quality parameters and their ability to diminish the impact of the pathogen Verticillium dahliae were investigated. While shoot biomass of young plants was enhanced between 10% and 20% by the endophytes DSE48 and L. orchidicola in one of two experiments and by DSE49 in both experiments, vegetative growth parameters of 24-week-old plants were not affected except a reproducible increase of root diameter by the isolate DSE49. Concerning fruit yield and quality, L. orchidicola could double the biomass of tomatoes and increased glucose content by 17%, but this was dependent on date of harvest and on root colonisation density. Additionally, the endophytes DSE49 and L. orchidicola decreased the negative effect of V. dahliae on tomato, but only at a low dosage of the pathogen. This indicates that the three dark septate endophytes can have a significant impact on tomato characters, but that the effects are only obvious at early stages of vegetative and generative development and currently too inconsistent to recommend the application of these DSEs in horticultural practice.

  16. Content of alpha-linolenic acid in human atrial tissue correlates with plasma levels of alpha-linolenic acid

    DEFF Research Database (Denmark)

    Gu, Jiwei; Eschen, Rikke Bülow; Andreasen, Annette

    and ALA levels were compared by the Pearson correlation coefficient. Results: There was a statistical significant correlation (r=0.54, 95% confidence interval: 0.30-0.71) between levels of ALA in plasma phospholipids and atrial tissue. Conclusion: The content of ALA in plasma phospholipids is a short term...... indicator of intake of ALA and this correlated well with the content of ALA in atrial tissue. Atrial tissue is not readily available but this study shows that determination of plasma phospholipids may be useful to further investigate an antiarrhythmic effect of ALA on AF....

  17. Prostacyclins have no direct inotropic effect on isolated atrial strips from the normal and pressure-overloaded human right heart.

    Science.gov (United States)

    Holmboe, Sarah; Andersen, Asger; Jensen, Rebekka V; Kimose, Hans Henrik; Ilkjær, Lars B; Shen, Lei; Clapp, Lucie H; Nielsen-Kudsk, Jens Erik

    2017-01-01

    Prostacyclins are vasodilatory agents used in the treatment of pulmonary arterial hypertension. The direct effects of prostacyclins on right heart function are still not clarified. The aim of this study was to investigate the possible direct inotropic properties of clinical available prostacyclin mimetics in the normal and the pressure-overloaded human right atrium. Trabeculae from the right atrium were collected during surgery from chronic thromboembolic pulmonary hypertension (CTEPH) patients with pressure-overloaded right hearts, undergoing pulmonary thromboendarterectomy (n = 10) and from patients with normal right hearts operated by valve replacement or coronary bypass surgery (n = 9). The trabeculae were placed in an organ bath, continuously paced at 1 Hz. They were subjected to increasing concentrations of iloprost, treprostinil, epoprostenol, or MRE-269, followed by isoprenaline to elicit a reference inotropic response. The force of contraction was measured continuously. The expression of prostanoid receptors was explored through quantitative polymerase chain reaction (qPCR). Iloprost, treprostinil, epoprostenol, or MRE-269 did not alter force of contraction in any of the trabeculae. Isoprenaline showed a direct inotropic response in both trabeculae from the pressure-overloaded right atrium and from the normal right atrium. Control experiments on ventricular trabeculae from the pig failed to show an inotropic response to the prostacyclin mimetics. qPCR demonstrated varying expression of the different prostanoid receptors in the human atrium. In conclusion, prostacyclin mimetics did not increase the force of contraction of human atrial trabeculae from the normal or the pressure-overloaded right heart. These data suggest that prostacyclin mimetics have no direct inotropic effects in the human right atrium.

  18. I(f) blocking potency of ivabradine is preserved under elevated endotoxin levels in human atrial myocytes.

    Science.gov (United States)

    Scheruebel, Susanne; Koyani, Chintan N; Hallström, Seth; Lang, Petra; Platzer, Dieter; Mächler, Heinrich; Lohner, Karl; Malle, Ernst; Zorn-Pauly, Klaus; Pelzmann, Brigitte

    2014-07-01

    Lower heart rate is associated with better survival in patients with multiple organ dysfunction syndrome (MODS), a disease mostly caused by sepsis. The benefits of heart rate reduction by ivabradine during MODS are currently being investigated in the MODIfY clinical trial. Ivabradine is a selective inhibitor of the pacemaker current If and since If is impaired by lipopolysaccharide (LPS, endotoxin), a trigger of sepsis, we aimed to explore If blocking potency of ivabradine under elevated endotoxin levels in human atrial cardiomyocytes. Treatment of myocytes with S-LPS (containing the lipid A moiety, a core oligosaccharide and an O-polysaccharide chain) but not R595 (an O-chain lacking LPS-form) caused If inhibition under acute and chronic septic conditions. The specific interaction of S-LPS but not R595 to pacemaker channels HCN2 and HCN4 proves the necessity of O-chain for S-LPS-HCN interaction. The efficacy of ivabradine to block If was reduced under septic conditions, an observation that correlated with lower intracellular ivabradine concentrations in S-LPS- but not R595-treated cardiomyocytes. Computational analysis using a sinoatrial pacemaker cell model revealed that despite a reduction of If under septic conditions, ivabradine further decelerated pacemaking activity. This novel finding, i.e. If inhibition by ivabradine under elevated endotoxin levels in vitro, may provide a molecular understanding for the efficacy of this drug on heart rate reduction under septic conditions in vivo, e.g. the MODIfY clinical trial.

  19. Atrial Fibrillation.

    Science.gov (United States)

    Zimetbaum, Peter

    2017-03-07

    This issue provides a clinical overview of atrial fibrillation, focusing on diagnosis, treatment, and practice improvement. The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including MKSAP (Medical Knowledge and Self-Assessment Program). Annals of Internal Medicine editors develop In the Clinic in collaboration with the ACP's Medical Education and Publishing divisions and with the assistance of additional science writers and physician writers.

  20. Two new septate junctions in the phylum Coelenterata.

    Science.gov (United States)

    Green, C R; Flower, N E

    1980-04-01

    Freeze-fracture of fixed and unfixed tissue, lanthanum tracer and conventional thin-section studies have revealed 2 new types of septate junction in the class Anthozoa, phylum Coelenterata. These new junctions have the 15-18-nm intercellular spacing of all other described septate junctions and are found around the apical circumference of cells lining a lumen or outside edge. However, in freeze-fracture replicas and tangential views of lanthanum-impregnated tissue, they are seen to be quite different from other known septate junction types. One of the new junctions is found in endothelial tissue such as that lining the gut or the inside of the tentacles. In tangential view it is seen to consist of relatively short, straight, double septa, again with lateral projections. In feeeze-fracture of unfixed tissue, the junction consists of double rows of particles on the P face, the particles of one row being rounded, those of the other being elongated at right angles to the line of the septum. This dichotomy in particle size is unexpected, as the 2 halves of the septa as seen in tangential view are symmetrical. In freeze-fracture of fixed material the particle arrays remain on the P face and appear similar to those of unfixed material, but never as clear. In fixed tissue, some distortion had occurred and in extreme cases septa appear as a single broad jumbled row of particles. In this double septa junction, the rows of particles seen in freeze-fracture are occasionally seen to anastomose with a septum dividing into 2 and a third row of particles aligning with the 2 new septa to form their double particle rows. In both fixed and unfixed tissues, the E face of the junction consists of wide, shallow grooves. The second of the new junctions occurs in epithelial tissue, such as around the outer edge of sea-anemone tentacles, and consists of long wavy septa with lateral projections. In views where these projections appear longest, they arise predominantly from one side of the

  1. Effect of microRNA-101 on atrial fibrosis in human chronic atrial fibrillation%微小RNA鄄101在心房颤动心房纤维化中的作用

    Institute of Scientific and Technical Information of China (English)

    蒋智渊; 钟国强; 肖飞; 何艳; 洪钰杰

    2015-01-01

    目的:探讨微小RNA-101(miRNA-101)在心房颤动心房纤维化中的作用。方法:59例开胸手术患者(心脏瓣膜病47例,先天性心脏病12例),分为房颤组30例、窦律组29例。qPCR及锁定核苷酸原位杂交技术检测两组右心耳 miRNA-101表达;qPCR 检测两组右心耳转化生长因子βⅠ型受体( TGFβRⅠ)、Ⅰ型胶原(COL1)mRNA 表达;免疫印迹法检测两组右心耳 TGFβRI、COL1蛋白表达;Masson 染色观察两组右心耳胶原的沉积。结果:房颤组右心耳 miRNA-101表达明显低于窦律组(P <0.05),原位杂交显示miRNA-101主要分布于心房结缔组织,房颤组 miRNA-101表达较窦律组下降24.9%;房颤组 TGFβRⅠmRNA表达与窦律组无明显差异(P >0.05),但蛋白表达明显高于窦律组(P <0.05);COL1mRNA及蛋白表达均明显高于窦律组(P <0.05);房颤组右心耳胶原沉积明显多于窦律组(P <0.05)。结论:miRNA-101下调在心房颤动心房纤维化过程中起重要作用,其可能通过调控TGFβRⅠ而参与心房纤维化。%Objective To investigate the effect of microRNA-101 (miRNA-101) on atrial fibrosis in human chronic atrial fibrillation (AF). Methods Right atrial appendages were obtained from 59 patients (30 with AF) undergoing cardiac surgery, including 47 patients with valve heart disease and 12 patients with congenital heart disease. The expression of miRNA-101 was determined by quantitative real-time PCR in the right atrial appendages of patients with and without AF. The cell-specific localization of miRNA-101 was detected by in situ hybridization assay. The mRNA and protein expression levels of transforming growth factor β typeⅠreceptor (TGFβRⅠ) and collagen type I (COL1) were determined by quantitative real-time PCR and Western-blot assay, respectively. Collagen in the right atrial appendages was observed by Masson staining assay. Results The expression

  2. Draft Genome Sequence of Microdochium bolleyi, a Dark Septate Fungal Endophyte of Beach Grass

    OpenAIRE

    David, Aaron S; Haridas, Sajeet; LaButti, Kurt; Lim, Joanne; Lipzen, Anna; Wang, Mei; Barry, Kerrie; Grigoriev, Igor V.; Spatafora, Joseph W.; May, Georgiana

    2016-01-01

    Here, we present the genome sequence of the dark septate fungal endophyte Microdochium bolleyi (Ascomycota, Sordariomycetes, Xylariales). The assembled genome size was 38.84 Mbp and consisted of 173 scaffolds and 13,177 predicted genes.

  3. Draft Genome Sequence of Microdochium bolleyi, a Dark Septate Fungal Endophyte of Beach Grass.

    Science.gov (United States)

    David, Aaron S; Haridas, Sajeet; LaButti, Kurt; Lim, Joanne; Lipzen, Anna; Wang, Mei; Barry, Kerrie; Grigoriev, Igor V; Spatafora, Joseph W; May, Georgiana

    2016-04-28

    Here, we present the genome sequence of the dark septate fungal endophyte Microdochium bolleyi (Ascomycota, Sordariomycetes, Xylariales). The assembled genome size was 38.84 Mbp and consisted of 173 scaffolds and 13,177 predicted genes.

  4. [Septate uterus with cervical duplication and vaginal partition: a rare malformation].

    Science.gov (United States)

    García-León, F; Kably-Ambe, A; Von-der-Meden, W; Dosal, M; Escarcega, H

    1998-12-01

    It presents three cases of Mullerian anomalies with septate uterus and cervical duplication and longitudinal vaginal septum. There are a few previous cases reported. The cases are discussed and the literature is revised.

  5. Preparation of mono-radioiodinated tracers for study of the in vivo metabolism of atrial natriuretic peptide in humans

    Energy Technology Data Exchange (ETDEWEB)

    Clerico, A. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Iervasi, G. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Manfredi, C. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Salvadori, S. [Dept. of Pharmaceutical Sciences, Univ. of Ferrara (Italy); Marastoni, M. [Dept. of Pharmaceutical Sciences, Univ. of Ferrara (Italy); Del Chicca, M.G. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Giannessi, D. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Del Ry, S. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Andreassi, M.G. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Sabatino, L. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Iascone, M.R. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Biagini, A. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Donato, L. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica

    1995-09-01

    The authors evaluate the optimum chemical conditions for labelling atrial natriuretic peptide (ANP) and its metabolites and for preparing highly purified radiotracers which can be used for in vivo kinetic studies of ANP in humans. Synthetic {alpha} h{sub 1-28}ANP and some hormone metabolites were iodinated with Na{sup 125}I or Na{sup 131}I by means of the lactoperoxidase (ANP) or the chloramine-T (ANP metabolites) technique. The biological activity of labelled ANP was tested by means of a binding study using mouse cardiac membranes. A high-performance liquid chromatography (HPLC) procedure was used to purify the labelled hormone and the principal labelled metabolites in venous plasma samples collected up to 50 min after the injection of {sup 125}I-labelled ANP from nine healthy men. The main ANP kinetic parameters were derived from the disappearance curves of the [{sup 125}I]ANP, which were satisfactorily fitted by a bi-exponential function in all subjects. The main advantages of this tracer technique are high accuracy, allowing the identification of the metabolites produced in vivo under steady-state conditions after injection of the precursor (labelled hormone) high sensitivity, allowing the detection of minimal quantities of metabolites high specificity, allowing the detection of possible in vitro artefactual generation of cleavage products of ANP using an internal labelled standard. Utilizing this tracer method, it was possible to estimate the principal parameters of ANP kinetics and also to plot the appearance curves of the labelled metabolites produced in vivo after the injection of the labelled precursor. (orig.). With 5 figs.

  6. Expression of Extracellular Signal-regulated Kinase and Angiotensin-converting Enzyme in Human Atria during Atrial Fibrillation

    Institute of Scientific and Technical Information of China (English)

    戴友平; 王祥; 曹林生; 杨杪; 邬堂春

    2004-01-01

    Summary: In order to investigate the changes in the expression of extracellular signal-regulated kinase (ERK1/ERK2) and angiotensin-converting enzyme (ACE) in the patients with atrial fibrillation (AF), 52 patients with rheumatic heart diseases were examined. Nineteen patients had chronic persistent AF (AF≥6 months, CAF), 12 patients had paroxymal AF (PAF) and 21 patients had no history of AF. The ERK expression was detected at the mRNA level by reverse transcription polymerase chain reaction, at the protein level by Western blotting and at atrial tissue level by immunohistochemistry. ERK-activating kinases (MEK1/2) and ACE were determined by Western blotting techniques. The expression of ERK2-mRNA was increased in the patients with CAF (74±19 U vs sinus rhythm: 32±24 U, P<0.05). Activated ERK1/ERK2 and MEK1/2 were increased to more than 150 % in the patients with AF compared to those with sinus rhythm. No significant difference between CAF and PAF was found. The expression of ACE was three-fold increased in the patients with CAF compared to those with sinus rhythm. Patients with AF showed an increased expression of ERK1/ERK2 in atrial interstitial cells and marked atrial fibrosis. An ACE-dependent increase in the amounts of activated ERK1/ERK2 in atrial interstitial cells may be one of molecular mechanisms for the development of atrial fibrosis in the patients with AF. These findings may have important impact on the treatment of AF.

  7. The evidence of mycorrhizal fungi and dark septate endophytes in roots of Chlorophytum borivillianum

    OpenAIRE

    Mathew, Abraham; Malathy, Ramanpillai M.

    2008-01-01

    Mycorrhizal and dark septate endophyte in Chlorophytum borivillianum cultivated in different parts of south- west India was found. Dark septate fungi with melanized hyphae and microsclerotia were documented. During culturing of the microsclerotia-containing roots, fungi with `Rhizoctonia-like’ characters developed. The fungi showed reluctance in sporulation but produced microsclerotia in the medium. Specific taxa and their ecological role can be attributed only after detailed studies as diffe...

  8. Distribution and function of sodium channel subtypes in human atrial myocardium

    NARCIS (Netherlands)

    Kaufmann, Susann G.; Westenbroek, Ruth E.; Maass, Alexander H.; Lange, Volkmar; Renner, Andre; Wischmeyer, Erhard; Bonz, Andreas; Muck, Jenny; Ertl, Georg; Catterall, William A.; Scheuer, Todd; Maier, Sebastian K. G.

    2013-01-01

    Voltage-gated sodium channels composed of a pore-forming alpha subunit and auxiliary beta subunits are responsible for the upstroke of the action potential in cardiac muscle. However, their localization and expression patterns in human myocardium have not yet been clearly defined. We used immunohist

  9. Prenatal management, pregnancy and pediatric outcomes in fetuses with septated cystic hygroma

    Directory of Open Access Journals (Sweden)

    C.Y. Sanhal

    2014-09-01

    Full Text Available It has been reported that, compared with simple increased nuchal translucency, fetal cases with septated cystic hygroma (CH are more likely to face perinatal handicaps. However, pediatric outcomes and proper prenatal counseling for this anomaly have not yet been truly defined. We performed this study to determine pregnancy and pediatric outcomes of fetuses with septated CH. We searched records for cases with septated CH and collected data for structural abnormalities, karyotype analysis, and pregnancy outcomes. Fetuses born with septated CH were also evaluated for their pediatric outcomes. Sixty-nine fetuses with septated CH were enrolled in the study. Results showed that chromosomal abnormalities were present in 28 fetuses (40.6%, and the most common aneuploidy was Turner syndrome (n=14, 20.3%; 16 (23.2% of the remaining cases, in which aneuploidy was not found, had coexistent structural malformations; 25 (36.2% cases had normal karyotype and morphology. The total number of live births and infants with unfavorable neurologic follow-up were 13 (18.8% and 2 (2.9%, respectively. Septated CH is associated with poor perinatal outcomes; therefore, karyotype analysis and ultrasonographic anomaly screening should be performed as initial steps, and expectant management should be offered to couples with euploid fetuses that have normal morphology.

  10. Isolation of cardiac myosin light-chain isotypes by chromatofocusing. Comparison of human cardiac atrial light-chain 1 and foetal ventricular light-chain 1.

    Science.gov (United States)

    Vincent, N D; Cummins, P

    1985-04-01

    Cardiac myosin light chain isotypes have been resolved using chromatofocusing, a new preparative column chromatographic technique. The method relies on production of narrow-range, shallow and stable pH gradients using ion-exchange resins and buffers with even buffering capacity over the required pH range. Light chains were resolved in order of decreasing isoelectric point in the pH range 5.2-4.5. Gradients of delta pH = 0.004-0.006/ml elution volume were achieved which were capable of resolving light chains with isoelectric point differences of only 0.03. Analytical isoelectric focusing of light chains in polyacrylamide gels could be used to predict the results of preparative chromatofocusing for method development. Chromatofocusing was capable of resolving human and bovine cardiac light chain 1 and 2 subunits, atrial (ALC) and ventricular (VLC) light chain isotypes and homologous VLC-2 and VLC-2* light chains. The technique was used to purify and resolve the human foetal ventricular light chain 1 (FLC-1) from adult ventricular light chain 1 (VLC-1) present in foetal ventricles and the atrial light chain 1 (ALC-1) in adult atria. Comparative peptide mapping studies and amino acid analyses were carried out on FLC-1 and ALC-1. No differences were detected between FLC-1 and ALC-1 using three different proteases and amino acid compositions were similar with the exception of glycine content. The studies indicate that FLC-1 and ALC-1 are homologous, and possibly identical, light chains. Comparison of human FLC-1/ALC-1 with VLC-1 suggested marked structural and chemical differences in these light chain isotypes, in particular in the contents of methionine, proline, lysine and alanine residues. Differences in the contents of these residues were also apparent in the corresponding bovine atrial and ventricular light chains [Wikman-Coffelt, J. & Srivastava, S. (1979) FEBS Lett. 106, 207-212]. The latter three residues are known to be rich in the N-termini of cardiac and

  11. Dark septate endophytic pleosporalean genera from semiarid areas.

    Science.gov (United States)

    Knapp, D G; Kovács, G M; Zajta, E; Groenewald, J Z; Crous, P W

    2015-12-01

    Dark septate endophytes (DSE) are distributed worldwide as root-colonising fungi, and frequent in environments with strong abiotic stress. DSE is not a taxon, but constitutes numerous fungal taxa belonging to several orders of Ascomycota. In this study we investigate three unidentified DSE lineages belonging to Pleosporales that were found previously in semiarid sandy grasslands. For molecular phylogenetic studies seven loci (ITS, partial 18S nrRNA, 28S nrRNA, actin, calmodulin, transcription-elongation factor 1- α and ß -tubulin genes) were amplified and sequenced. Based on morphology and the resulting molecular phylogeny these isolates were found to represent three novel genera within the Pleosporales, namely Aquilomyces, Flavomyces and Darksidea, with eight novel species. Molecular data revealed that monotypic Aquilomyces belongs to Morosphaeriaceae, monotypic Flavomyces represents an incertae sedis lineage related to Massarinaceae, and Darksidea, with six new species, is allied to the Lentitheciaceae. During this study we tested numerous conditions to induce sporulation, and managed for the first time to induce several DSE to form their sexual morphs.

  12. Arbuscular mycorrhizal and dark septate endophyte associations of medicinal plants

    Directory of Open Access Journals (Sweden)

    Szymon Zubek

    2011-10-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF and dark septate endophyte (DSE associations were studied in 36 medicinal plant species from 33 genera and 17 families, collected from the Botanical Garden of the Jagiellonian University in Kraków. Arbuscular mycorrhiza (AM was found in 34 species (94%; 26 were of the Arum-type, 4 – Paris and 4 taxa revealed intermediate morpho­logy. The abundance of AMF hyphae in roots varied with particular species, ranging from 2.5% (Helianthus tuberosus to 77.9% (Convallaria majalis. The mycelium of DSE was observed in 13 plant species (36%, however, the percentage of root colonization by these fungi was low. Spores of 7 AMF species (Glomeromycota were isolated from trap cultures established from rhizosphere soils of the investigated plants: Archaeospora trappei (Archaeosporaceae, Glomus aureum, Glomus caledonium, Glomus claroideum, Glomus constrictum, Glomus mosseae, Glomus versiforme (Glomeraceae. Our results are the first detailed report of root endophyte associations of the plant species under study. Moreover, the mycorrhizal status of 14 plant species is reported for the first time.

  13. Reproductive outcome of septate uterus following hysteroscopic septum resection

    Directory of Open Access Journals (Sweden)

    Priya Selvaraj

    2010-01-01

    Full Text Available Objective : To evaluate the reproductive outcome following hysteroscopic septum resection in patients with primary and secondary (recurrent pregnancy loss [RPL] and bad obstetric history [BOH] infertility. Study Design : Retrospective study. Materials and Methods : Hysteroscopic septum resection was performed on 26 patients with a history of either recurrent pregnancy loss, BOH or infertility. The septum resection was performed using a bipolar versapoint system. Reproductive performance of these patients after septum resection was analyzed. The main outcome measures were clinical pregnancy and live birth rates. Results : Hysteroscopic septum resection was performed on seven patients with the history of secondary infertility. Post operatively, the pregnancy rate was 86% (n=6, and the live birth rate was 67% (n=4. After septum resection in 19 primary infertile patients, 6 (32% patients conceived which resulted in live birth rates of 67% (n=4. Conclusion : Hysteroscopic septum resection using bipolar versapoint system is an effective and safe approach for the removal of septum. Hysteroscopic septum resection in women with septate uterus significantly improves the live birth rates and future fertility is not impaired.

  14. Structural inhibition and reactivation of Escherichia coli septation by elements of the SOS and TER pathways

    Energy Technology Data Exchange (ETDEWEB)

    Dopazo, A.; Tormo, A.; Aldea, M.; Vicente, M.

    1987-04-01

    The inhibition of cell division caused by induction of the SOS pathway in Escherichia coli structurally blocks septation, as deduced from two sets of results. Potential septation sites active at the time of SOS induction became inactivated, while those initiated during the following doubling time were active. Penicillin resistance increased in wild-type UV light-irradiated cells, a behavior similar to that observed in mutants in which structural blocks were introduced by inactivation of FtsA. Potential septation sites that have been structurally blocked by either the SOS division inhibitor, furazlocillin inhibition of PBP3, or inactivation of a TER pathway component, FtsA3, could be reactivated one doubling time after removal of the inhibitory agent in the presence of an active lon gene product. Reactivation of potential septation sites blocked by the presence of an inactivated FtsA3 was significantly lower when the lon protease was not active, suggesting that Lon plays a role in the removal of inactivated TER pathway products from the blocked potential septation sites.

  15. Dimensions, septation, and pattern of pneumatization of the sphenoidal sinus.

    Science.gov (United States)

    Idowu, O E; Balogun, B O; Okoli, C A

    2009-11-01

    The endoscopic endonasal transsphenoidal approach (EEA) to treat sellar, parasellar, and suprasellar tumours continues to gain increased significance. Due to the close proximity of the sphenoid sinus to the carotid artery and the optic canal, it is very important for surgeons to know the anatomical features and variations of the sphenoid sinus as relevant to EEA. A prospective study of the sphenoid sinus morphology was carried out on the cranial tomographic (CT) scan images of 60 Nigerian adult patients. The CTs were reviewed regarding the different anatomical variations of the sphenoid sinus: dimensions, septation, and pattern of pneumatisation. There were 37 males and 23 females. The patients' ages ranged from 18 years to 85 years, with a mean of 47.2 years. There was a main single intersphenoid septum in most patients (95%). The insertion of the septum was usually to the right posteriorly (38%) and in the midline anterior (65%). Although there is usually a main septum, the septa present were multiple in 29 of the sinuses studied. There was no gender difference with respect to the attachment of the main sphenoid sinus septum. The sphenoid anterior, posterior, and transverse dimensions were not significantly dependent on age, but they were longer in males than in females. Sellar pneumatization was present in the majority of the patients (83%), with 4 patients having postsellar pneumatization (6.7%) and 3 patients having presellar pneumatization (5%). There were no cases with conchal pneumatization or lateral pneumatization of the greater wing of the sphenoid. The present study provides anatomical information about the sphenoid sinus dimensions morphology that is essential for avoiding complications in performing an endoscopic sphenoidotomy.

  16. Selection of reference genes is critical for miRNA expression analysis in human cardiac tissue. A focus on atrial fibrillation

    Science.gov (United States)

    Masè, Michela; Grasso, Margherita; Avogaro, Laura; D’Amato, Elvira; Tessarolo, Francesco; Graffigna, Angelo; Denti, Michela Alessandra; Ravelli, Flavia

    2017-01-01

    MicroRNAs (miRNAs) are emerging as key regulators of complex biological processes in several cardiovascular diseases, including atrial fibrillation (AF). Reverse transcription-quantitative polymerase chain reaction is a powerful technique to quantitatively assess miRNA expression profile, but reliable results depend on proper data normalization by suitable reference genes. Despite the increasing number of studies assessing miRNAs in cardiac disease, no consensus on the best reference genes has been reached. This work aims to assess reference genes stability in human cardiac tissue with a focus on AF investigation. We evaluated the stability of five reference genes (U6, SNORD48, SNORD44, miR-16, and 5S) in atrial tissue samples from eighteen cardiac-surgery patients in sinus rhythm and AF. Stability was quantified by combining BestKeeper, delta-Cq, GeNorm, and NormFinder statistical tools. All methods assessed SNORD48 as the best and U6 as the worst reference gene. Applications of different normalization strategies significantly impacted miRNA expression profiles in the study population. Our results point out the necessity of a consensus on data normalization in AF studies to avoid the emergence of divergent biological conclusions. PMID:28117343

  17. Atrial fibrillation: a new look at an old arrhythmia

    NARCIS (Netherlands)

    Meijler, F.L.

    1983-01-01

    The ventricular rhythm during atrial fibrillation in human beings is random because the excitatory process of atrial fibrillation itself is almost certainly a random phenomenon. It remains random because A V junctional memory is too short to inftuence the sequence of conducted impulses . In human be

  18. Bub2 regulation of cytokinesis and septation in budding yeast

    Directory of Open Access Journals (Sweden)

    Park Su Young

    2009-06-01

    contraction. Our data suggest that the overexpression of the Bub2 fusion protein acts as a dominant negative, leading to septation defects by a mechanism that is Tem1-dependent.

  19. Atrial fibrillation.

    Science.gov (United States)

    Bang, Casper N

    2013-10-01

    Atrial fibrillation (AF) is a common complication after myocardial infarction (MI) and new-onset AF has been demonstrated to be associated with adverse outcome and a large excess risk of death in both MI and aortic stenosis (AS) patients. Prevention of new-onset AF is therefore a potential therapeutic target in AS and MI patients. Lipid-lowering drugs, particularly statins, have anti-inflammatory and antioxidant properties that may prevent AF. Accordingly, statins are recommended as a class IIa recommendation for prevention of new-onset AF after coronary artery bypass grafting (CABG). However, this preventive effect has not been investigated on new-onset AF in asymptomatic patients with AS or a large scale first-time MI patient sample and data in patients not undergoing invasive cardiac interventions are limited. This PhD thesis was conducted at the Heart Centre, Rigshospitalet, Denmark, with the aim to investigate the three aforementioned questions and to add to the existing evidence of AF prevention with statins. This was done using three different settings: 1) a randomized patients sample of 1,873 from the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study, 2) a register patient sample of 97,499 with first-time MI, and 3) all published studies until beginning of June 2011 examining statin treatment on new-onset and recurrent AF in patients not undergoing cardiac surgery. This thesis revealed that statins did not lower the incidence or the time to new-onset AF in patients with asymptomatic AS. However, statin treatment showed an independently preventive effect on new-onset AF, including type-dependent effect and a trend to dosage-dependent effect. In addition, this thesis showed that good compliance to statin treatment was important to prevent new-onset AF. Finally, the meta-analysis in this PhD thesis showed a preventive effect in the observational studies although this effect was absent in the randomized controlled trials. Based on this PhD thesis

  20. Inhibition by atrial and brain natriuretic peptides of endothelin-1 secretion after stimulation with angiotensin II and thrombin of cultured human endothelial cells.

    Science.gov (United States)

    Kohno, M; Yasunari, K; Yokokawa, K; Murakawa, K; Horio, T; Takeda, T

    1991-01-01

    We examined the inhibition by atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) of endothelin-1 secretion stimulated by angiotensin II (ANGII) and thrombin using cultured human umbilical-vein endothelial cells. ANGII and thrombin dose-dependently stimulated immunoreactive (ir) endothelin-1 secretion. Human ANP(1-28) and human BNP-32 both inhibited such secretion in a dose-dependent way. Inhibition of this secretion by ANP and BNP was paralleled by an increase in the level of cyclic guanosine 5'-monophosphate (GMP). The addition of a cyclic GMP analogue, 8-bromo cyclic GMP, reduced this stimulated secretion. Rat ANP(5-25) was weaker than human ANP(1-28) at inhibiting ir-endothelin-1 secretion and increasing cyclic GMP in the cells. ir-Endothelin-1 in the medium consisted of two components separated by high pressure liquid chromatography; the major one corresponded to endothelin-1(1-21) and the minor one corresponded to big endothelin-1(1-38). Treatment with ANP and BNP did not affect this profile. These findings suggest that human ANP and BNP inhibit endothelin-1 secretion stimulated by ANGII and thrombin in these cells through a cyclic GMP-dependent process. Taken together with endothelin stimulation of ANP and BNP secretion from the heart, our results suggest the existence of a cardiac-endothelium feedback. PMID:1645748

  1. Endometrial carcinoma located in the right septate uterus cavity: a case report.

    Science.gov (United States)

    Boubess, Ikram; Mahdi, Youssef; Ramsiss, Hanan; Filali, Adib; Alami, Mohamad Hassan; El Khannoussi, Basma; Hachi, Hafid

    2015-01-01

    Endometrial cancer in patients with uterine congenital malformations is exceptional and there are only a few rare cases published in the literature. We report the case of a 67 years-old patient with an endometrial cancer located in the right cavity of a complete septate uterus.

  2. Recurrence quantification analysis applied to spatiotemporal pattern analysis in high-density mapping of human atrial fibrillation.

    Science.gov (United States)

    Zeemering, Stef; Bonizzi, Pietro; Maesen, Bart; Peeters, Ralf; Schotten, Ulrich

    2015-01-01

    Spatiotemporal complexity of atrial fibrillation (AF) patterns is often quantified by annotated intracardiac contact mapping. We introduce a new approach that applies recurrence plot (RP) construction followed by recurrence quantification analysis (RQA) to epicardial atrial electrograms, recorded with a high-density grid of electrodes. In 32 patients with no history of AF (aAF, n=11), paroxysmal AF (PAF, n=12) and persistent AF (persAF, n=9), RPs were constructed using a phase space electrogram embedding dimension equal to the estimated AF cycle length. Spatial information was incorporated by 1) averaging the recurrence over all electrodes, and 2) by applying principal component analysis (PCA) to the matrix of embedded electrograms and selecting the first principal component as a representation of spatial diversity. Standard RQA parameters were computed on the constructed RPs and correlated to the number of fibrillation waves per AF cycle (NW). Averaged RP RQA parameters showed no correlation with NW. Correlations improved when applying PCA, with maximum correlation achieved between RP threshold and NW (RR1%, r=0.68, p <; 0.001) and RP determinism (DET, r=-0.64, p <; 0.001). All studied RQA parameters based on the PCA RP were able to discriminate between persAF and aAF/PAF (DET persAF 0.40 ± 0.11 vs. 0.59 ± 0.14/0.62 ± 0.16, p <; 0.01). RP construction and RQA combined with PCA provide a quick and reliable tool to visualize dynamical behaviour and to assess the complexity of contact mapping patterns in AF.

  3. Alterations in gene expression of proteins involved in the calcium handling in patients with atrial fibrillation

    NARCIS (Netherlands)

    Van Gelder, IC; Brundel, BJJM; Henning, RH; Tuinenburg, AE; Tieleman, RG; Deelman, L; Grandjean, JG; De Kam, PJ; Van Gilst, WH; Crijns, HJGM

    1999-01-01

    Gene Expression in Human Atrial Fibrillation, Introduction: Atrial fibrillation (AF) leads to a loss of atrial contraction within hours to days. During persistence of AF, cellular dedifferentiation and hypertrophy occur, eventually resulting in degenerative changes and cell death, Abnormalities in t

  4. Gata4 potentiates second heart field proliferation and Hedgehog signaling for cardiac septation.

    Science.gov (United States)

    Zhou, Lun; Liu, Jielin; Xiang, Menglan; Olson, Patrick; Guzzetta, Alexander; Zhang, Ke; Moskowitz, Ivan P; Xie, Linglin

    2017-02-21

    GATA4, an essential cardiogenic transcription factor, provides a model for dominant transcription factor mutations in human disease. Dominant GATA4 mutations cause congenital heart disease (CHD), specifically atrial and atrioventricular septal defects (ASDs and AVSDs). We found that second heart field (SHF)-specific Gata4 heterozygote embryos recapitulated the AVSDs observed in germline Gata4 heterozygote embryos. A proliferation defect of SHF atrial septum progenitors and hypoplasia of the dorsal mesenchymal protrusion, rather than anlage of the atrioventricular septum, were observed in this model. Knockdown of the cell-cycle repressor phosphatase and tensin homolog (Pten) restored cell-cycle progression and rescued the AVSDs. Gata4 mutants also demonstrated Hedgehog (Hh) signaling defects. Gata4 acts directly upstream of Hh components: Gata4 activated a cis-regulatory element at Gli1 in vitro and occupied the element in vivo. Remarkably, SHF-specific constitutive Hh signaling activation rescued AVSDs in Gata4 SHF-specific heterozygous knockout embryos. Pten expression was unchanged in Smoothened mutants, and Hh pathway genes were unchanged in Pten mutants, suggesting pathway independence. Thus, both the cell-cycle and Hh-signaling defects caused by dominant Gata4 mutations were required for CHD pathogenesis, suggesting a combinatorial model of disease causation by transcription factor haploinsufficiency.

  5. Left atrial volume index

    DEFF Research Database (Denmark)

    Poulsen, Mikael K; Dahl, Jordi S; Henriksen, Jan Erik;

    2013-01-01

    To determine the prognostic importance of left atrial (LA) dilatation in patients with type 2 diabetes (T2DM) and no history of cardiovascular disease.......To determine the prognostic importance of left atrial (LA) dilatation in patients with type 2 diabetes (T2DM) and no history of cardiovascular disease....

  6. Septation and shortening of outflow tract in embryonic mouse heart involve changes in cardiomyocyte phenotype and α-SMA positive cells in the endocardium

    Institute of Scientific and Technical Information of China (English)

    杨艳萍; 李海荣; 景雅

    2004-01-01

    Background Studies on human, rat and chicken embryos have demonstrated that during the period of outflow tract septation, retraction of the distal myocardial margin of the outflow tract from the junction with aortic sac to the level of semilunar valves leads to the shortening of the myocardial tract. However, the mechanism is not clear. So we investigated the mechanism of outflow tract shortening and remodeling and the spatio-temporal distribution pattern of α-SMA positive cells in the outflow tract cushion during septation of the outflow tract in the embryonic mouse heart. Methods Serial sections of mouse embryos from embryonic day 9 (ED 9) to embryonic day 16 (ED 16) were stained with monoclonal antibodies against α-SCA, α-SMA, or desmin, while apoptosis was assessed using the terminal deoxyribonucleotidy transferase-mediated dUTP-digoxigenin nick-end labeling (TUNEL) assay. Results Between ED 11 and ED 12, the cardiomyocytes in the distal portion of the outflow tract were observed losing their myocardial phenotype without going into apoptosis, suggesting that trans-differentiation of cardiomyocytes into the cell components of the free walls of the intrapericardial ascending aorta and pulmonary trunk. The accumulation of α-SMA positive cells in the cardiac jelly began on ED 10 and participated in the ridge fusion and septation of the outflow tract. Fusion of the distal ridges resulted in the formation of the facing walls of the intrapericardial ascending aorta and pulmonary trunk. Fusion of the proximal ridges was accompanied by the accumulation of α-SMA positive cells into a characteristic central whorl, in which cell apoptosis could be observed. Subsequent myocardialization resulted in the formation of the partition between the subaortic and subpulmonary vestibules. Conclusions The shortening of the embryonic heart outflow tract in mice may result not from apoptosis, but from the trans-differentiation of cells with cardiomyocyte phenotype in the distal

  7. An unsuspected metabolic role for atrial natriuretic peptides: the control of lipolysis, lipid mobilization, and systemic nonesterified fatty acids levels in humans.

    Science.gov (United States)

    Lafontan, Max; Moro, Cédric; Sengenes, Coralie; Galitzky, Jean; Crampes, François; Berlan, Michel

    2005-10-01

    In normal and obese humans, lipid mobilization and systemic nonesterified fatty acid levels are thought to be acutely controlled by catecholamines (ie, epinephrine and norepinephrine) and insulin. Natriuretic peptides (NPs) are known to play a key role in the regulation of salt and water balance and blood pressure homeostasis. They are involved in the pathophysiology of hypertension and heart failure. NPs have recently been found to exert potent lipolytic effects (ie, activating the breakdown of stored triacylglycerols) in isolated human fat cells and to promote lipid mobilization in vivo. Atrial natriuretic peptide increases the intracellular 3', 5'-cyclic guanosine monophosphate (cGMP) concentration which activates cGMP-dependent protein kinase leading to perilipin and hormone-sensitive lipase phosphorylation and lipolysis. NPs promote lipid mobilization when administered intravenously. NPs are also responsible for the residual lipid-mobilizing action observed under oral beta-blockade in subjects performing physical exercise. NPs are therefore novel factors which may open promising research pathways to explain the control of lipid mobilization in physiological and pathological conditions. The metabolic impact of altered production and circulation of NPs remains to be established. The potential influence of NPs on the development of lipid disorders, obesity-related cardiovascular events, and cardiac cachexia will be discussed in this review.

  8. Clinical Study of Recombinant Human atrial Natriuretic Peptide in Treatment of Acute Heart Failure%重组人心钠肽治疗急性心力衰竭的临床研究

    Institute of Scientific and Technical Information of China (English)

    贺宇峰

    2015-01-01

    目的:探讨重组人心钠肽治疗急性心力衰竭疗效。方法:对自2011年5月~2013年2月我院收治的急性心力衰竭患者应用重组人心钠肽治疗,于用药前后监测患者的血流动力学参数。结果:66例患者59例症状缓解,显效27例,有效32例,无效7例,有效率89.39%。结论:重组人心钠肽是治疗急性心力衰竭疗效可靠的药物,安全性高。%Objective:To investigate the recombinant human atrial natriuretic peptide in treatment of acute heart failure efficacy .Meth-ods:the application of recombinant human atrial natriuretic peptide in patients with acute heart failure treatment since 2011 May to 2013 February in our hospital , in hemodynamic parameters monitoring of patients before and after treatment .Results:of the 66 patients, 59 ca-ses of remission, 27 cases markedly effective, effective 32 cases, invalid 7 cases, efficiency of 89.39%.Conclusion:recombinant human atrial natriuretic peptide drugs and reliable effect in the treatment of acute heart failure , high safety.

  9. The Ly6 protein coiled is required for septate junction and blood brain barrier organisation in Drosophila.

    Directory of Open Access Journals (Sweden)

    Assia Hijazi

    Full Text Available BACKGROUND: Genetic analysis of the Drosophila septate junctions has greatly contributed to our understanding of the mechanisms controlling the assembly of these adhesion structures, which bear strong similarities with the vertebrate tight junctions and the paranodal septate junctions. These adhesion complexes share conserved molecular components and have a common function: the formation of paracellular barriers restraining the diffusion of solutes through epithelial and glial envelopes. METHODOLOGY/PRINCIPAL FINDINGS: In this work we characterise the function of the Drosophila cold gene, that codes for a protein belonging to the Ly6 superfamily of extracellular ligands. Analysis of cold mutants shows that this gene is specifically required for the organisation of the septate junctions in epithelial tissues and in the nervous system, where its contribution is essential for the maintenance of the blood-brain barrier. We show that cold acts in a cell autonomous way, and we present evidence indicating that this protein could act as a septate junction component. CONCLUSION/SIGNIFICANCE: We discuss the specific roles of cold and three other Drosophila members of the Ly6 superfamily that have been shown to participate in a non-redundant way in the process of septate junction assembly. We propose that vertebrate Ly6 proteins could fulfill analogous roles in tight junctions and/or paranodal septate junctions.

  10. The internodal atrial myocardium.

    Science.gov (United States)

    Anderson, R H; Ho, S Y; Smith, A; Becker, A E

    1981-09-01

    The anatomical substrates of internodal conduction have long been a contentious topic. Debated first by the German Pathological Society in 1910, the consensus of established opinion for over half a century was that conduction between sinus and atrioventricular nodes occurred through plain myocardium. This was a conclusion supported by Truex in 1961. Despite his restatement of this fact in 1976, it has become fashionable to describe internodal conduction as being mediated by specialized internodal pathways. To reinvestigate this problem we studied 22 human fetal and 32 human infant hearts. In each case it was possible to cut the atrial tissues as a single block of tissue and to examine serial sections through the internodal myocardium. The sinus node, atrioventricular node, and segments of atrioventricular ring specialized tissue were recognized as specialized tissue using the light microscope in each heart. In contrast, there was nothing "special" about the myocardium between the nodes, nor was it possible to recognize tracts on the basis of either histological appearance or cellular architecture. It is concluded that, from the standpoint of light microscopy, there is no evidence whatsoever to support the purported concept of specialized anatomical substrates for internodal conduction.

  11. Differential regulation of atrial natriuretic peptide- and adrenergic receptor-dependent lipolytic pathways in human adipose tissue.

    Science.gov (United States)

    Moro, Cédric; Polak, Jan; Richterova, Blanka; Sengenès, Coralie; Pelikanova, Terezie; Galitzky, Jean; Stich, Vladimir; Lafontan, Max; Berlan, Michel

    2005-01-01

    The aim of the study was to investigate the regulation affecting the recently described atrial natriuretic peptide (ANP)-dependent lipolytic pathway in comparison with the adrenergic lipolytic cascade. We studied in vivo the effect of a euglycemic-hyperinsulinemic clamp on the changes occurring in the extracellular glycerol concentration (EGC) of subcutaneous adipose tissue (SCAT) during ANP or epinephrine perfusion in a microdialysis probe. Homologous desensitization and the incidence of hyperinsulinemia on the ANP- and catecholaminergic-dependent control of lipolysis were also investigated in vitro on fat cells from SCAT. When perfused in SCAT, epinephrine and ANP promoted an increase in EGC; the EGC increase was significantly lower during the clamp. The reduction of epinephrine-induced lipolysis was limited (18%) when phentolamine (an alpha(2)-adrenergic receptor [AR] antagonist) was perfused together with epinephrine. Unlike the effect of epinephrine, the response to ANP observed during the second perfusion was reduced by 32%. The increase in extracellular guanosine 3',5' -cyclic monophosphate concentration, which reflects ANP activity, was also reduced during the second perfusion. Desensitization of the lipolytic effects of ANP was observed in vitro after a 2-hour period of recovery, while the effects of alpha(2)-AR agonist or of epinephrine were unchanged. Insulin was without any effect on ANP-induced lipolysis and alpha(2)-AR-mediated antilipolysis, while it reduced beta-AR-induced lipolysis. The ANP-dependent lipolytic pathway undergoes desensitization in vitro and in situ. Insulin had no inhibitory effect on either ANP- or alpha(2)-AR-dependent pathways, while it counteracted the beta-AR pathway.

  12. Atrial natriuretic peptide contribution to lipid mobilization and utilization during head-down bed rest in humans.

    Science.gov (United States)

    Moro, Cédric; Pillard, Fabien; de Glisezinski, Isabelle; Crampes, Francois; Thalamas, Claire; Harant, Isabelle; Marques, Marie-Adeline; Lafontan, Max; Berlan, Michel

    2007-08-01

    Head-down bed rest (HDBR) increases plasma levels of atrial natriuretic peptide (ANP) and decreases norepinephrine levels. We previously demonstrated that ANP promotes lipid mobilization and utilization, an effect independent of sympathetic nervous system activation, when infused into lean healthy men at pharmacological doses. The purpose of the present study was to demonstrate that a physiological increase in ANP contributes to lipid mobilization and oxidation in healthy young men. Eight men were positioned for 4 h in a sitting (control) or in a HDBR position. Indexes of lipid mobilization and hormonal changes were measured in plasma. Extracellular glycerol, an index of lipolysis, was determined in subcutaneous adipose tissue (SCAT) with a microdialysis technique. A twofold increase in plasma ANP concentration was observed after 60 min of HDBR, and a plateau was maintained thereafter. Plasma norepinephrine decreased by 30-40% during HDBR, while plasma insulin and glucose levels did not change. The level of plasma nonesterified fatty acids was higher during HDBR. SCAT lipolysis, as reflected by interstitial glycerol, as well as interstitial cGMP, the second messenger of the ANP pathway, increased during HDBR. This was associated with an increase in blood flow observed throughout HDBR. Significant changes in respiratory exchange ratio and percent use of lipid and carbohydrate were seen only after 3 h of HDBR. Thus the proportion of lipid oxidized increased by 40% after 3 h of HDBR. The rise in plasma ANP during HDBR was associated with increased lipolysis in SCAT and whole body lipid oxidation. In this physiological setting, independent of increasing catecholamines, our study suggests that ANP contributes to lipid mobilization and oxidation in healthy young men.

  13. Effects of beta-blockade on atrial and atrioventricular nodal refractoriness, and atrial fibrillatory rate during atrial fibrillation in pigs

    NARCIS (Netherlands)

    van den Berg, MP; van de Ven, LLM; Witting, W; Crijns, JGM; Haaksma, J; Bel, KJ; de Langen, CDJ; Lie, KI

    1997-01-01

    Despite their widespread use in atrial fibrillation, the effects of beta-adrenoceptor blockers on atrial and atrioventricular (AV) nodal refractoriness, and atrial fibrillatory rate during atrial fibrillation have been incompletely characterised. In particular, it is unknown whether additional sodiu

  14. Arbuscular Mycorrhizal and Dark Septate Endophyte Fungal Associations in South Indian Aquatic and Wetland Macrophytes

    OpenAIRE

    Kumar Seerangan; Muthukumar Thangavelu

    2014-01-01

    Investigations on the prevalence of arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungal symbioses are limited for plants growing in tropical aquatic and wetland habitats compared to those growing on terrestrial moist or dry habitats. Therefore, we assessed the incidence of AM and DSE symbiosis in 8 hydrophytes and 50 wetland plants from four sites in south India. Of the 58 plant species examined, we found AM and DSE fungal symbiosis in 21 and five species, respectively. We rep...

  15. Surgery for atrial fibrillation.

    Science.gov (United States)

    Lawrance, Christopher P; Henn, Matthew C; Damiano, Ralph J

    2014-11-01

    Atrial fibrillation is the most common cardiac arrhythmia, and its treatment options include drug therapy or catheter-based or surgical interventions. The surgical treatment of atrial fibrillation has undergone multiple evolutions over the last several decades. The Cox-Maze procedure went on to become the gold standard for the surgical treatment of atrial fibrillation and is currently in its fourth iteration (Cox-Maze IV). This article reviews the indications and preoperative planning for performing a Cox-Maze IV procedure. This article also reviews the literature describing the surgical results for both approaches including comparisons of the Cox-Maze IV to the previous cut-and-sew method.

  16. Foxf genes integrate tbx5 and hedgehog pathways in the second heart field for cardiac septation.

    Directory of Open Access Journals (Sweden)

    Andrew D Hoffmann

    2014-10-01

    Full Text Available The Second Heart Field (SHF has been implicated in several forms of congenital heart disease (CHD, including atrioventricular septal defects (AVSDs. Identifying the SHF gene regulatory networks required for atrioventricular septation is therefore an essential goal for understanding the molecular basis of AVSDs. We defined a SHF Hedgehog-dependent gene regulatory network using whole genome transcriptional profiling and GLI-chromatin interaction studies. The Forkhead box transcription factors Foxf1a and Foxf2 were identified as SHF Hedgehog targets. Compound haploinsufficiency for Foxf1a and Foxf2 caused atrioventricular septal defects, demonstrating the biological relevance of this regulatory network. We identified a Foxf1a cis-regulatory element that bound the Hedgehog transcriptional regulators GLI1 and GLI3 and the T-box transcription factor TBX5 in vivo. GLI1 and TBX5 synergistically activated transcription from this cis-regulatory element in vitro. This enhancer drove reproducible expression in vivo in the posterior SHF, the only region where Gli1 and Tbx5 expression overlaps. Our findings implicate Foxf genes in atrioventricular septation, describe the molecular underpinnings of the genetic interaction between Hedgehog signaling and Tbx5, and establish a molecular model for the selection of the SHF gene regulatory network for cardiac septation.

  17. Foxf genes integrate tbx5 and hedgehog pathways in the second heart field for cardiac septation.

    Science.gov (United States)

    Hoffmann, Andrew D; Yang, Xinan Holly; Burnicka-Turek, Ozanna; Bosman, Joshua D; Ren, Xiaomeng; Steimle, Jeffrey D; Vokes, Steven A; McMahon, Andrew P; Kalinichenko, Vladimir V; Moskowitz, Ivan P

    2014-10-01

    The Second Heart Field (SHF) has been implicated in several forms of congenital heart disease (CHD), including atrioventricular septal defects (AVSDs). Identifying the SHF gene regulatory networks required for atrioventricular septation is therefore an essential goal for understanding the molecular basis of AVSDs. We defined a SHF Hedgehog-dependent gene regulatory network using whole genome transcriptional profiling and GLI-chromatin interaction studies. The Forkhead box transcription factors Foxf1a and Foxf2 were identified as SHF Hedgehog targets. Compound haploinsufficiency for Foxf1a and Foxf2 caused atrioventricular septal defects, demonstrating the biological relevance of this regulatory network. We identified a Foxf1a cis-regulatory element that bound the Hedgehog transcriptional regulators GLI1 and GLI3 and the T-box transcription factor TBX5 in vivo. GLI1 and TBX5 synergistically activated transcription from this cis-regulatory element in vitro. This enhancer drove reproducible expression in vivo in the posterior SHF, the only region where Gli1 and Tbx5 expression overlaps. Our findings implicate Foxf genes in atrioventricular septation, describe the molecular underpinnings of the genetic interaction between Hedgehog signaling and Tbx5, and establish a molecular model for the selection of the SHF gene regulatory network for cardiac septation.

  18. Colonization of roots of cultivated Solanum lycopersicum by dark septate and other ascomycetous endophytes.

    Science.gov (United States)

    Andrade-Linares, Diana Rocio; Grosch, Rita; Franken, Philipp; Rexer, Karl-Heinz; Kost, Gerhard; Restrepo, Silvia; de Garcia, Maria Caridad Cepero; Maximova, Eugenia

    2011-01-01

    Tomato (Solanum lycopersicum L.) roots from four different crop sites in Colombia were surface sterilized and 51 fungal isolates were obtained and conserved for further analysis. Based on microscopical observations and growth characteristics, 20 fungal isolates corresponded to genus Fusarium, six presented asexual conidia different from Fusarium, eight were sterile mycelia, seven of which had dark septate hyphae and 17 did not continue to grow on plates after being recovered from conservation. Growth on different media, detailed morphological characterization and ITS region sequencing of the six sporulating and eight sterile isolates revealed that they belonged to different orders of Ascomycota and that the sterile dark septate endophytes did not correspond to the well known Phialocephala group. Interactions of nine isolates with tomato plantlets were assessed in vitro. No effect on shoot development was revealed, but three isolates caused brown spots in roots. Colonization patterns as analyzed by confocal microscopy differed among the isolates and ranged from epidermal to cortical penetration. Altogether 11 new isolates from root endophytic fungi were obtained, seven of which showed features of dark septate endophytes. Four known morphotypes were represented by five isolates, while six isolates belonged to five morphotypes of putative new unknown species.

  19. Lulwoana sp., a dark septate endophyte in roots of Posidonia oceanica (L.) Delile seagrass.

    Science.gov (United States)

    Torta, L; Lo Piccolo, S; Piazza, G; Burruano, S; Colombo, P; Ottonello, D; Perrone, R; Di Maida, G; Pirrotta, M; Tomasello, A; Calvo, S

    2015-03-01

    Posidonia oceanica is the most common, widespread and important monocotyledon seagrass in the Mediterranean Basin, and hosts a large biodiversity of species, including microorganisms with key roles in the marine environment. In this study, we ascertain the presence of a fungal endophyte in the roots of P. oceanica growing on different substrata (rock, sand and matte) in two Sicilian marine meadows. Staining techniques on root fragments and sections, in combination with microscope observations, were used to visualise the fungal presence and determine the percentage of fungal colonisation (FC) in this tissue. In root fragments, statistical analysis of the FC showed a higher mean in roots anchored on rock than on matte and sand. In root sections, an inter- and intracellular septate mycelium, producing intracellular microsclerotia, was detected from the rhizodermis to the vascular cylinder. Using isolation techniques, we obtained, from both sampling sites, sterile, slow-growing fungal colonies, dark in colour, with septate mycelium, belonging to the dark septate endophytes (DSEs). DNA sequencing of the internal transcribed spacer (ITS) region identified these colonies as Lulwoana sp. To our knowledge, this is the first report of Lulwoana sp. as DSE in roots of P. oceanica. Moreover, the highest fungal colonisation, detected in P. oceanica roots growing on rock, suggests that the presence of the DSE may help the host in several ways, particularly in capturing mineral nutrients through lytic activity.

  20. Grainy head promotes expression of septate junction proteins and influences epithelial morphogenesis.

    Science.gov (United States)

    Narasimha, Maithreyi; Uv, Anne; Krejci, Alena; Brown, Nicholas H; Bray, Sarah J

    2008-03-15

    Transcription factors of the Grainy head (Grh) family are required in epithelia to generate the impermeable apical layer that protects against the external environment. This function is conserved in vertebrates and invertebrates, despite the differing molecular composition of the protective barrier. Epithelial cells also have junctions that create a paracellular diffusion barrier (tight or septate junctions). To examine whether Grh has a role in regulating such characteristics, we used an epidermal layer in the Drosophila embryo that has no endogenous Grh and lacks septate junctions, the amnioserosa. Expression of Grh in the amnioserosa caused severe defects in dorsal closure, a process similar to wound closure, and induced robust expression of the septate junction proteins Coracle, Fasciclin 3 and Sinuous. Grh-binding sites are present within the genes encoding these proteins, consistent with them being direct targets. Removal of Grh from imaginal disc cells caused a reduction in Fasciclin 3 and Coracle levels, suggesting that Grh normally fine tunes their epithelial expression and hence contributes to barrier properties. The fact that ectopic Grh arrests dorsal closure also suggests that this dynamic process relies on epithelia having distinct adhesive properties conferred by differential deployment of Grh.

  1. Left Atrial Ablation for Atrial Fibrillation

    Science.gov (United States)

    Sternik, Leonid; Schaff, Hartzel V.; Luria, David; Glikson, Michael; Kogan, Alexander; Malachy, Ateret; First, Maya; Raanani, Ehud

    2011-01-01

    The maze procedure is the gold standard for the ablation of atrial fibrillation, and the “box lesion” around the pulmonary veins is the most important part of this procedure. We have created this lesion with a bipolar radiofrequency ablator, abandoning the usual use of this device (to achieve bilateral epicardial isolation of the pulmonary veins). From March 2004 through the end of May 2010, we performed surgical ablation of atrial fibrillation in 240 patients. Of this number, 205 underwent operation by a hybrid maze technique and the remaining 35 (our study cohort) underwent the creation of a box lesion around the pulmonary veins by means of a bipolar radiofrequency device. Ablation lines were created by connecting the left atriotomy to the amputated left atrial appendage, with 2 ablation lines made with a bipolar radiofrequency device above and below the pulmonary veins. Lesions were made along the transverse and oblique sinuses by epicardial and endocardial application of a bipolar device. The left atrial isthmus was ablated by bipolar radiofrequency and cryoprobe. No complications were associated with the box lesion: 90% and 89% of patients were in sinus rhythm at 3 and 6 months of follow-up, respectively. By creating a box lesion around the pulmonary veins, we expect to improve transmurality by means of epicardial and endocardial ablation of 1 rather than 2 layers of atrial wall, as in epicardial pulmonary vein isolation. Isolation of the entire posterior wall of the left atrium is better electrophysiologically and renders dissection around the pulmonary veins unnecessary. PMID:21494518

  2. What Is Atrial Fibrillation?

    Science.gov (United States)

    ... regular beat. Certain cells in your heart make electric signals that cause the heart to contract and pump ... read your ECG to find out if the electric signals are normal. In atrial fibrillation (AFib), the heart’s ...

  3. A mutation in the atrial-specific myosin light chain gene (MYL4) causes familial atrial fibrillation.

    Science.gov (United States)

    Orr, Nathan; Arnaout, Rima; Gula, Lorne J; Spears, Danna A; Leong-Sit, Peter; Li, Qiuju; Tarhuni, Wadea; Reischauer, Sven; Chauhan, Vijay S; Borkovich, Matthew; Uppal, Shaheen; Adler, Arnon; Coughlin, Shaun R; Stainier, Didier Y R; Gollob, Michael H

    2016-04-12

    Atrial fibrillation (AF), the most common arrhythmia, is a growing epidemic with substantial morbidity and economic burden. Mechanisms underlying vulnerability to AF remain poorly understood, which contributes to the current lack of highly effective therapies. Recognizing mechanistic subtypes of AF may guide an individualized approach to patient management. Here, we describe a family with a previously unreported syndrome characterized by early-onset AF (age <35 years), conduction disease and signs of a primary atrial myopathy. Phenotypic penetrance was complete in all mutation carriers, although complete disease expressivity appears to be age-dependent. We show that this syndrome is caused by a novel, heterozygous p.Glu11Lys mutation in the atrial-specific myosin light chain gene MYL4. In zebrafish, mutant MYL4 leads to disruption of sarcomeric structure, atrial enlargement and electrical abnormalities associated with human AF. These findings describe the cause of a rare subtype of AF due to a primary, atrial-specific sarcomeric defect.

  4. The Connexin40A96S mutation from a patient with atrial fibrillation causes decreased atrial conduction velocities and sustained episodes of induced atrial fibrillation in mice.

    Science.gov (United States)

    Lübkemeier, Indra; Andrié, René; Lickfett, Lars; Bosen, Felicitas; Stöckigt, Florian; Dobrowolski, Radoslaw; Draffehn, Astrid M; Fregeac, Julien; Schultze, Joachim L; Bukauskas, Feliksas F; Schrickel, Jan Wilko; Willecke, Klaus

    2013-12-01

    Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and a major cause of stroke. In the mammalian heart the gap junction proteins connexin40 (Cx40) and connexin43 (Cx43) are strongly expressed in the atrial myocardium mediating effective propagation of electrical impulses. Different heterozygous mutations in the coding region for Cx40 were identified in patients with AF. We have generated transgenic Cx40A96S mice harboring one of these mutations, the loss-of-function Cx40A96S mutation, as a model for atrial fibrillation. Cx40A96S mice were characterized by immunochemical and electrophysiological analyses. Significantly reduced atrial conduction velocities and strongly prolonged episodes of atrial fibrillation were found after induction in Cx40A96S mice. Analyses of the gating properties of Cx40A96S channels in cultured HeLa cells also revealed significantly lower junctional conductance and enhanced sensitivity voltage gating of Cx40A96S in comparison to Cx40 wild-type gap junctions. This is caused by reduced open probabilities of Cx40A96S gap junction channels, while single channel conductance remained the same. Similar to the corresponding patient, heterozygous Cx40A96S mice revealed normal expression levels and localization of the Cx40 protein. We conclude that heterozygous Cx40A96S mice exhibit prolonged episodes of induced atrial fibrillation and severely reduced atrial conduction velocities similar to the corresponding human patient.

  5. Left atrial appendage occlusion

    Directory of Open Access Journals (Sweden)

    Ahmad Mirdamadi

    2013-01-01

    Full Text Available Left atrial appendage (LAA occlusion is a treatment strategy to prevent blood clot formation in atrial appendage. Although, LAA occlusion usually was done by catheter-based techniques, especially percutaneous trans-luminal mitral commissurotomy (PTMC, it can be done during closed and open mitral valve commissurotomy (CMVC, OMVC and mitral valve replacement (MVR too. Nowadays, PTMC is performed as an optimal management of severe mitral stenosis (MS and many patients currently are treated by PTMC instead of previous surgical methods. One of the most important contraindications of PTMC is presence of clot in LAA. So, each patient who suffers of severe MS is evaluated by Trans-Esophageal Echocardiogram to rule out thrombus in LAA before PTMC. At open heart surgery, replacement of the mitral valve was performed for 49-year-old woman. Also, left atrial appendage occlusion was done during surgery. Immediately after surgery, echocardiography demonstrates an echo imitated the presence of a thrombus in left atrial appendage area, although there was not any evidence of thrombus in pre-pump TEE. We can conclude from this case report that when we suspect of thrombus of left atrial, we should obtain exact history of previous surgery of mitral valve to avoid misdiagnosis clotted LAA, instead of obliterated LAA. Consequently, it can prevent additional evaluations and treatments such as oral anticoagulation and exclusion or postponing surgeries including PTMC.

  6. Haploinsufficiency of the Sec7 guanine nucleotide exchange factor gea1 impairs septation in fission yeast.

    Directory of Open Access Journals (Sweden)

    Alan M Eckler

    Full Text Available Membrane trafficking is essential to eukaryotic life and is controlled by a complex network of proteins that regulate movement of proteins and lipids between organelles. The GBF1/GEA family of Guanine nucleotide Exchange Factors (GEFs regulates trafficking between the endoplasmic reticulum and Golgi by catalyzing the exchange of GDP for GTP on ADP Ribosylation Factors (Arfs. Activated Arfs recruit coat protein complex 1 (COP-I to form vesicles that ferry cargo between these organelles. To further explore the function of the GBF1/GEA family, we have characterized a fission yeast mutant lacking one copy of the essential gene gea1 (gea1+/-, the Schizosaccharomyces pombe ortholog of GBF1. The haploinsufficient gea1+/- strain was shown to be sensitive to the GBF1 inhibitor brefeldin A (BFA and was rescued from BFA sensitivity by gea1p overexpression. No overt defects in localization of arf1p or arf6p were observed in gea1+/- cells, but the fission yeast homolog of the COP-I cargo sac1 was mislocalized, consistent with impaired COP-I trafficking. Although Golgi morphology appeared normal, a slight increase in vacuolar size was observed in the gea1+/- mutant strain. Importantly, gea1+/- cells exhibited dramatic cytokinesis-related defects, including disorganized contractile rings, an increased septation index, and alterations in septum morphology. Septation defects appear to result from altered secretion of enzymes required for septum dynamics, as decreased secretion of eng1p, a β-glucanase required for septum breakdown, was observed in gea1+/- cells, and overexpression of eng1p suppressed the increased septation phenotype. These observations implicate gea1 in regulation of septum breakdown and establish S. pombe as a model system to explore GBF1/GEA function in cytokinesis.

  7. Pseudosigmoidea ibarakiensis sp. nov., a Dark Septate Endophytic Fungus from a Cedar Forest in Ibaraki, Japan

    OpenAIRE

    Diene, Ousmane; Wang, Wei; Narisawa, Kazuhiko

    2013-01-01

    A dark septate fungus of Pseudosigmoidea, Hyphomycetes, was recovered from forest soil in Ibaraki prefecture, Japan. The isolate is characterized by pale to brown conidia with up to 8 septa measuring 68–132 × 4–7.9 μm. It is also unique in producing conidia borne by long conidogenious cells in agar medium with or without water, compared to P. cranei, which must be immersed in water to sporulate. Morphological analysis indicated that the isolate is distinct from P. cranei and is described as a...

  8. Integrin β1 Participates in Atrial Remodeling in Rapid Atrial Pacing Induced Canine Atrial Fibrillation Model

    Institute of Scientific and Technical Information of China (English)

    Zhang wei; Yang guirong; Zheng zhaotong; Wang sujia; Zhang yun

    2004-01-01

    @@ Objective Integrin β1 regulates cell to cell and cell to extracellualr matrix interaction in heart. however, its pathop hysiological role in atrial fibrillation is unclear. The purpose of t his study was to determine whether atrial structural remodeling during atrial fibrillation is associated with altered integrinβ1.

  9. Stroke prevention in atrial fibrillation

    DEFF Research Database (Denmark)

    Freedman, Ben; Potpara, Tatjana S; Lip, Gregory Y H

    2016-01-01

    Atrial fibrillation is found in a third of all ischaemic strokes, even more after post-stroke atrial fibrillation monitoring. Data from stroke registries show that both unknown and untreated or under treated atrial fibrillation is responsible for most of these strokes, which are often fatal...... or debilitating. Most could be prevented if efforts were directed towards detection of atrial fibrillation before stroke occurs, through screening or case finding, and treatment of all patients with atrial fibrillation at increased risk of stroke with well-controlled vitamin K antagonists or non-vitamin K...

  10. Clinical Effects of Hysteroscopical Septate Uterus Section%宫腔镜子宫纵隔剪开术治疗纵隔子宫的临床疗效分析

    Institute of Scientific and Technical Information of China (English)

    魏丽娜; 孙秀芹

    2012-01-01

    目的 探讨宫腔镜子宫纵隔剪开术治疗纵隔子宫的临床疗效.方法 选择2009年10月至2011年2月于本院确诊的38例纵隔子宫患者为研究对象,对其进行超声监测下宫腔镜子宫纵隔剪开术.观察纵隔子宫诊断符合率及手术前、后孕产情况等(本研究遵循的程序符合本院人体试验委员会所制定的伦理学标准,得到该委员会批准,并征得受试对象本人的知情同意,并与之签署临床研究知情同意书).结果 宫腔镜检查纵隔子宫诊断符合率为100.0%.术后随访12~24个月,自然流产率由术前的80 0%(24/30)下降至术后的18 5%(5/27),足月活产率由术前的10 0%(3/30)上升至术后的55.6%(15/27).结论 宫腔镜子宫纵隔剪开术治疗纵隔子宫安全、有效,可明显改善患者孕产结局,可作为该病首选治疗方法.%Objective To explore the clinical effect of hysteroscopical septate uterus section in the treatment of septate uterus. Methods From October 2009 to February 2011, a total of 38 women with septate uterus were included in the study, and accepted hysteroscopical septate uterus section. Diagnostic accordance rate and pregnancy outcomes were observed. The study protocol was approved by the Ethical Review Board of Investigation in Human Being of Jining First People s Hospital. Informed consent was obtained from each patients. Results Diagnostic accordance rate of hysteroscopy was 100. 0%. Follow-up of 12 to 24 months, the spontaneous abortion rate was decreased from 80. 0%(24/30) to 18. 5% (5/27) , the full term-living birth rate was increased from 10. 0% (3/30) to 55. 6% (15/27). Conclusions Hysteroscopical septate uterus section is the most effective treatment for septate uterus, which can improve pregnant outcomes. So it can be used as the first choice of treatment of septate uterus.

  11. Tetralogy of Fallot Associated with Dysplastic Kidneys, Cloacal Anomalies, and Female Pseudohermaphroditism: A Systemic Anomaly of Septation?

    Directory of Open Access Journals (Sweden)

    José Morales-Roselló

    2012-01-01

    Full Text Available A 20-week fetus was diagnosed with tetralogy of Fallot and multicystic kidneys. The postmortem study showed missing müllerian structures with small streak ovaries, external male genitalia, and an abnormal cloacal septation (imperforate anus with a sigmoid colon opening in the bladder. As the observed anomalies were related with septation, a mechanism related with the activation of specific growth factors, we discuss the possibility of a disorder in the function of the bone morphogenetic proteins as a common cause for the widespread anomalies found in this fetus.

  12. Atrial natriuretic peptide in patients with heart failure and chronic atrial fibrillation : Role of duration of at atrial fibrillation

    NARCIS (Netherlands)

    Van Den Berg, MP; Crijns, HJGM; Van Veldhuisen, DJ; Van Gelder, IC; De Kam, PJ; Lie, KI

    1998-01-01

    The purpose of this study was to analyze the determinants of atrial natriuretic peptide level in patients with congestive heart failure and atrial fibrillation. In particular, the duration of atrial fibrillation was analyzed because atrial fibrillation per se might have a specific effect on atrial n

  13. Changes in human atrial myocyte dimension among different ages%不同年龄人心房肌细胞的形态观察

    Institute of Scientific and Technical Information of China (English)

    孙秀梅; 胡小琴; 苏俊武; 潘世伟; 刘迎龙

    2001-01-01

    AIM: To observe the changes in right atrial myocyte dimensionswith myocardial development. METHODS: Cell length, width, length/width and cross-sectional area were measured in right atrial myocytes isolated from 12 weaning [ages 0.4-5 years, (1.8±1.3) years, n=103 cells], 10 young [6-11 years, (9.3±1.8) years, n=104 cells], 13 adult [30-56 years, (43.7±11.5) years, n=110 cells] human hearts. RESULTS: Cell length, width, length/width and cross-sectional area, at weanling group were (70.2±1.3) μm, (8.0±0.2) μm, (9.0±0.2) and (50.9±2.6) μm2, respectively, at young group were (93.5±1.6) μm, (11.7±0.3) μm, 8.1±0.2, (109.7±5.8) μm2, and (100.9±2.2) μm, (12.1±0.3) μm, 8.5±0.2, (119.0±5.5) μm2 for adult group. Clearly, young myocyte lenght, width, cross-sectional area were greater than that of myocytes at weanling group(P<0.01) but adult myocytes length/width and cross-sectional area increase slightly compared with young group. The length/width ratio has no significant change through myocyte maturity, which is between 8-9. CONCLUSIONS: Our data suggest that myocyte dimensions expect length/width ratio have increased progressively with maturity, the length/width ratio is preserved in atrial myocyte during the period of normal myocyte growth from weanling to adulthood, and these changes in myocyte dimensions are similar with ventricular myocytes changes from other mammalian species.%的:观察不同年龄人心房肌细胞的形态变化。方法:取右心房组织块进行酶解,得到单个细胞。分别观察小儿组(12例0.4-5岁,平均1.8岁±1.3岁,n=103个细胞)、儿童组(10例6-11岁,平均9.3岁±1.8岁,n=104)、成年组(13例30-56岁,平均43.7岁±11.5岁,n=110)病人心房肌细胞的长、宽(直径)、长/宽比和细胞横截面积(±s)。结果:细胞长(μm)小儿组为70.2±1.3,儿童组为93.5±1.6,成年组为100.8±2.2,细胞宽(μm)分别为8.0±0.2、11.7±0.3、12.0±0.3

  14. Atrial tissue expression of receptor for advanced glycation end-products (RAGE) and atrial fibrosis in patients with mitral valve disease.

    Science.gov (United States)

    Yang, Pil-Sung; Lee, Seung Hyun; Park, Junbeom; Kim, Tae-Hoon; Uhm, Jae-Sun; Joung, Boyoung; Lee, Moon-Hyoung; Chang, Byung-Chul; Pak, Hui-Nam

    2016-10-01

    It has been reported that receptor for advanced glycation end-products (RAGE) plays a significant role in cardiac fibrosis. Nonetheless, the precise relationship between the RAGE and atrial fibrosis has never been studied in humans. The aim of this study was to determine whether degree of atrial fibrosis was associated with atrial tissue expression of RAGE in patients with mitral valve disease (MVD). We collected human left atrial (LA) appendage tissue from 25 patients who underwent mitral valve surgery. We quantified the expression of RAGE and other protein markers by Western blotting and compared these levels with histological evaluations. RAGE expression in the LA appendage tissue was significantly correlated with atrial fibrosis (r=0.681, p=0.001). RAGE expression (regression coefficient [B] 9.49, 95% confidence interval [CI] 4.76-14.2, pRAGE expression was significantly correlated with protein expression of von Willebrand factor (r=0.659, pRAGE expression than those with no, mild, or moderate MS (p=0.013). Patients with MVD and atrial fibrillation (AF) had more severe atrial fibrosis (p=0.024) and higher RAGE expression (p=0.047) than those who remained in sinus rhythm. Atrial tissue expression of RAGE was significantly associated with atrial fibrosis, severe MS, and AF rhythm in patients with MVD. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. Nitrogen form influences the response of Deschampsia antarctica to dark septate root endophytes.

    Science.gov (United States)

    Upson, Rebecca; Read, David J; Newsham, Kevin K

    2009-11-01

    Fungi with dematiaceous septate hyphae, termed dark septate endophytes (DSE), are common in plant roots, particularly in cold-stressed habitats, but their effects on their host plants remain obscure. Here, we report a study that assessed the effects of six DSE on the growth and nutrient balance of Deschampsia antarctica when plants were supplied with the same amount of nitrogen in organic (casein hydrolysate) or inorganic (ammonium sulphate) form under controlled conditions. After 60 days, the DSE, that had each been isolated from D. antarctica and which analyses of internal transcribed spacer and large subunit regions indicated were similar to members of the Helotiales (Oculimacula yallundae, Mollisia and Tapesia spp.) and unassigned anamorphic ascomycetes, typically had no effect on, or reduced by 33-71%, shoot and root dry weights relative to uninoculated controls when plants had been supplied with nitrogen in inorganic form. In contrast, the DSE usually enhanced shoot and root dry weights by 51-247% when plants had been supplied with organic nitrogen. In the presence of inorganic nitrogen, only sporadic effects of DSE were recorded on shoot and root nitrogen or phosphorus concentrations, whereas in the presence of organic nitrogen, three to six of the DSE isolates increased shoot and root nitrogen and phosphorus contents. Most of the isolates decreased the phosphorus concentrations of shoots and roots when plants had been supplied with nitrogen in organic form. Our data suggest that DSE are able to mineralise peptides and amino acids in the rhizosphere, making nitrogen more freely available to roots.

  16. Aneurysm of the Right Atrial Appendage

    Directory of Open Access Journals (Sweden)

    Silvio Henrique Barberato

    2002-02-01

    Full Text Available Atrial aneurysms involving the free wall or atrial appendage are rare entities in cardiology practice and may be associated with atrial arrhythmias or embolic phenomena. We review the literature and report a case of aneurysm of the right atrial appendage in a young adult, whose diagnosis was established with echocardiography after an episode of paroxysmal atrial flutter.

  17. Modulation of atrial fibrillation

    NARCIS (Netherlands)

    Geuzebroek, G.S.C.

    2013-01-01

    In this thesis we investigate the results of various surgical procedures for atrial fibrillation which have been performed in the last 2 decades in the Sint Antonius Hospital, Nieuwegein, The Netherlands. In the 1990s the classical Maze III procedure was the main surgical technique for drug-refracto

  18. Lesson Five Atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    鲁端; 吴文烈

    2003-01-01

    @@ Atrial fibrillation(AF) may occur in paroxysmaland persistent forms. It may be seen in normal subjects,particularly during emotional stress or follow-ing surgery,exercise, or acute alcoholic intoxication.It also may occur in patients with heart or lungdisease who develop acute hypoxia, hypercapnia,ormetabolic or hemodynamic derangements.

  19. Protective effect of. cap alpha. -human atrial natriuretic polypeptide (. cap alpha. -hANP) on chemical-induced pulmonary edema

    Energy Technology Data Exchange (ETDEWEB)

    Imamura, T.; Ohnuma, N.; Iwasa, F.; Furuya, M.; Hayashi, Y.; Inomata, N.; Ishihara, T.; Noguchi, T.

    1988-01-01

    It has been established that ..cap alpha..-hANP, the newly discovered peptide extracted from human cardiac atria, has potent natriuretic and hypotensive actions. The authors present investigation is the first to demonstrate that ..cap alpha..-hANP is capable of protecting against pulmonary edema caused by various chemicals, using isolated perfused guinea pig lung system. Lungs were perfused via pulmonary artery with Krebs-Ringer bicarbonate buffer at 5.0 ml/min, and wet weight of lungs and perfusion pressure of pulmonary artery (Pa) were monitored. Bolus injection of Triton-X or CHAPS into cannulated pulmonary artery produced enema as indicated by a massive increase in wet weight and a slight increase in Pa. Constant infusion of ..cap alpha..-hANP through pulmonary artery at 200 ng/ml was effective in causing decrease in wet weight of lung. Perfusion of lung with paraquat or PGF/sub 2..cap alpha..'/, and repeated bolus injection of arachidonic acid or PGE/sub 2/ caused elevation in both wet weight of lung and Pa.

  20. Anatomically and morphologically unique dark septate endophytic association in the roots of the Mediterranean endemic seagrass Posidonia oceanica.

    Science.gov (United States)

    Vohník, Martin; Borovec, Ondřej; Župan, Ivan; Vondrášek, David; Petrtýl, Miloslav; Sudová, Radka

    2015-11-01

    Roots of terrestrial plants host a wide spectrum of soil fungi that form various parasitic, neutral and mutualistic associations. A similar trend is evident in freshwater aquatic plants and plants inhabiting salt marshes or mangroves. Marine vascular plants (seagrasses), by contrast, seem to lack specific root-fungus symbioses. We examined roots of two Mediterranean seagrasses, Posidonia oceanica and Cymodocea nodosa, in the northwestern Mediterranean Sea for fungal colonization using light and scanning and transmission electron microscopy. We found that P. oceanica, but not C. nodosa, is regularly associated with melanized septate hyphae in a manner resembling colonization by the ubiquitous dark septate endophytes (DSE) in roots of most terrestrial plants. P. oceanica roots were found to be colonized by sparse dematiaceous running hyphae as well as dense parenchymatous nets/hyphal sheaths on the root surface, intracellular melanized microsclerotia and occasionally also intra- and intercellular hyphae. The colonization was most prominent in the thick-walled hypodermis of the thinnest healthy looking roots, and the mycobiont seemed to colonize both living and dead host cells. Dark septate hyphae infrequently occurred also inside rhizodermal cells, but never colonized vascular tissues. The biological significance of this overlooked marine symbiosis remains unknown, but its morphology, extent, distribution across the NW Mediterranean Sea and absence in C. nodosa indicate an intriguing relationship between the dominant Mediterranean seagrass and its dark septate root mycobionts.

  1. Ergosterol content in ericaceous hair roots correlates with dark septate endophytes but not with ericoid mycorrhizal colonization

    DEFF Research Database (Denmark)

    Olsrud, Maria; Michelsen, Anders; Wallander, Håkon

    2007-01-01

    The relationship between ergosterol content in ericaceous hair roots and ericoid mycorrhizal (ErM) colonization versus dark septate endophytic (DSE) hyphal colonization was examined in a dwarf shrub-dominated subarctic mire in Northern Sweden. Ergosterol content in hair roots did not correlate...

  2. Dark septate root endophytic fungi increase growth of Scots pine seedlings under elevated CO2 through enhanced nitrogen use efficiency.

    NARCIS (Netherlands)

    Alberton, O.; Kuyper, T.W.; Summerbell, R.C.

    2010-01-01

    Although increasing concentrations of atmospheric CO2 are predicted to have substantial impacts on plant growth and functioning of ecosystems, there is insufficient understanding of the responses of belowground processes to such increases. We investigated the effects of different dark septate root e

  3. HYPERTHYROIDISM AND ATRIAL FIBRILLATION

    Directory of Open Access Journals (Sweden)

    I. M. Marusenko

    2017-01-01

    Full Text Available Review on a problem of the development of atrial fibrillation in patients with thyrotoxicosis is presented. Thyrotoxicosis is one of the most frequent endocrine diseases, conceding only to a diabetes mellitus. The most frequent reasons of hyperthyroidism are Graves’ disease and functional thyroid autonomy. The authors give an analysis of data on the cardiac effects of thyrotoxicosis, features of heart remodeling under the influence of thyroid hyperfunction, prevalence of atrial fibrillation in thyrotoxicosis, depending on age, as well as the possibility of restoring sinus rhythm in the combination of these diseases. Particular attention is paid to the effect on the heart of subclinical thyrotoxicosis, which is defined as a dysfunction of the thyroid gland, characterized by low serum concentration of thyrotropin, normal values of free thyroxine and free triiodothyronine. Subclinical hyperthyroidism is also capable of causing heart remodeling and diastolic dysfunction.Prevalence of thyrotoxicosis in elderly people is higher in areas of iodine deficiency; it is relevant for our country due to the large territory of iodine deficiency. In elderly patients, the cardiac effects of thyrotoxicosis prevail in the clinical picture, that makes it difficult to diagnose endocrine disorders, and correction of thyrotoxicosis is critically important for the successful control of the heart rhythm. The article also discusses the problem of thyrotoxic cardiomyopathy, caused by the toxic effect of excess thyroid hormones: features of this heart disorder, factors affecting its formation, clinical significance and contribution to the development of rhythm disturbances. The greatest significance is the development of atrial fibrillation as a result of thyrotox-icosis in older patients who already have various cardiovascular diseases.Atrial fibrillation is the most frequent heart rhythm disorder in thyrotoxicosis. The main cause of arrhythmia in hyperthyroidism is the

  4. Atrial fibrillation in the elderly

    Institute of Scientific and Technical Information of China (English)

    Roberto A.Franken; Ronaldo F.Rosa; Silvio CM Santos

    2012-01-01

    This review discusses atrial fibrillation according to the guidelines of Brazilian Society of Cardiac Arrhythmias and the Brazilian Cardiogeriatrics Guidelines. We stress the thromboembolic burden of atrial fibrillation and discuss how to prevent it as well as the best way to conduct cases of atrial fibrillatios in the elderly, reverting the arrhythmia to sinus rhythm, or the option of heart rate control. The new methods to treat atrial fibrillation, such as radiofrequency ablation, new oral direct thrombin inhibitors and Xa factor inhibitors, as well as new antiarrhythmic drugs, are depicted.

  5. Hypertension and Atrial Fibrillation

    DEFF Research Database (Denmark)

    Dzeshka, Mikhail S.; Shahid, Farhan; Shantsila, Alena

    2017-01-01

    Atrial fibrillation (AF) is the most prevalent sustained arrhythmia found in clinical practice. AF rarely exists as a single entity but rather as part of a diverse clinical spectrum of cardiovascular diseases, related to structural and electrical remodeling within the left atrium, leading to AF o...... of complications as the first clinical manifestation of the disease. Antithrombotic prevention in AF combined with strict blood pressure control is of primary importance, since stroke risk and bleeding risk are both greater with underlying hypertension....... onset, perpetuation, and progression. Due to the high overall prevalence within the AF population arterial hypertension plays a significant role in the pathogenesis of AF and its complications. Fibroblast proliferation, apoptosis of cardiomyocytes, gap junction remodeling, accumulation of collagen both...... in atrial and ventricular myocardium all accompany ageing-related structural remodeling with impact on electrical activity. The presence of hypertension also stimulates oxidative stress, systemic inflammation, rennin-angiotensin-aldosterone and sympathetic activation, which further drives the remodeling...

  6. Tolerance and antioxidant response of a dark septate endophyte (DSE), Exophiala pisciphila, to cadmium stress.

    Science.gov (United States)

    Zhan, Fangdong; He, Yongmei; Li, Tao; Yang, Yun-ya; Toor, Gurpal S; Zhao, Zhiwei

    2015-01-01

    The growth, oxidative damage and antioxidant response of Exophiala pisciphila ACCC32496, a dark septate endophyte isolated from an abandoned lead-zinc mining area, were measured at cadmium (Cd) concentrations of 0, 25, 50, 100, 200 and 400 mg L(-1). The EC50 values of E. pisciphila ACCC32496 to Cd were 332.2 mg L(-1) after 30 days on solid medium and 111.2 mg L(-1) after 7 days in liquid medium. Cd stress markedly stimulated the production of superoxide anion, H2O2 and malondialdehyde in the fungal mycelia. The activities of superoxide dismutase and catalase reached their maxima at 100 mg L(-1) Cd. The glutathione and non-protein thiol contents, along with the total antioxidant capability, reached their maxima at 50 mg L(-1) Cd. Low Cd concentrations induced a noticeable increase in antioxidant defense, while high Cd concentrations decreased the antioxidant defense.

  7. Interaction between a dark septate endophytic isolate from Dendrobium sp. and roots of D. nobile seedlings.

    Science.gov (United States)

    Hou, Xiao-Qiang; Guo, Shun-Xing

    2009-04-01

    Interactions between an isolate of dark septate endophytes (DSE) and roots of Dendrobium nobile Lindl. seedlings are reported in this paper. The isolate was obtained from orchid mycorrhizas on Dendrobium sp. in subtropical forest. The fungus formed typical orchid mycorrhiza in aseptic co-culture with D. nobile seedlings on modified Murashige-Skoog (MMS) medium. Anatomic observations of the infected roots showed that the DSE hyphae invaded the velamen layer, passed through passage cells in exodermis, entered the cortex cells, and then formed fungal pelotons of orchid mycorrhiza. D. nobile seedlings' plant height, stem diameter, new roots number and biomass were greatly enhanced by inoculating the fungus to seedlings. The fungus was identified as Leptodontidium by sequencing the polymerase chain reaction-amplified rDNA ITS1-5.8S-ITS2 (internal transcribed spacer (ITS)) regions and comparison with similar taxa.

  8. Inhibitory effects of hesperetin on Kv1.5 potassium channels stably expressed in HEK 293 cells and ultra-rapid delayed rectifier K(+) current in human atrial myocytes.

    Science.gov (United States)

    Wang, Huan; Wang, Hong-Fei; Wang, Chen; Chen, Yu-Fang; Ma, Rong; Xiang, Ji-Zhou; Du, Xin-Ling; Tang, Qiang

    2016-10-15

    In the present study, the inhibitory effects of hesperetin (HSP) on human cardiac Kv1.5 channels expressed in HEK 293 cells and the ultra-rapid delayed rectifier K(+) current (Ikur) in human atrial myocytes were examined by using the whole-cell configuration of the patch-clamp techniques. We found that hesperetin rapidly and reversibly suppressed human Kv1.5 current in a concentration dependent manner with a half-maximal inhibition (IC50) of 23.15 μΜ with a Hill coefficient of 0.89. The current was maximally diminished about 71.36% at a concentration of 300μM hesperetin. Hesperetin significantly positive shifted the steady-state activation curve of Kv1.5, while negative shifted the steady-state inactivation curve. Hesperetin also accelerated the inactivation and markedly slowed the recovery from the inactivation of Kv1.5 currents. Block of Kv1.5 currents by hesperetin was in a frequency dependent manner. However, inclusion of 30μM hesperetin in pipette solution produced no effect on Kv1.5 channel current, while the current were remarkable and reversibly inhibited by extracellular application of 30μM hesperetin. We also found that hesperetin potently and reversibly inhibited the ultra-repaid delayed K(+) current (Ikur) in human atrial myocytes, which is in consistent with the effects of hesperetin on Kv1.5 currents in HEK 293 cells. In conclusion, hesperetin is a potent inhibitor of Ikur (which is encoded by Kv1.5), with blockade probably due to blocking of both open state and inactivated state channels from outside of the cell.

  9. Atypical morphology of dark septate fungal root endophytes of Bouteloua in arid southwestern USA rangelands.

    Science.gov (United States)

    Barrow, J R

    2003-10-01

    Native grasses of semi-arid rangelands of the southwestern USA are more extensively colonized by dark septate endophytes (DSE) than by traditional mycorrhizal fungi. Roots of dominant grasses ( Bouteloua sp.) native to arid southwestern USA rangelands were prepared and stained using stains specific for fungi (trypan blue) and for lipids (sudan IV). This revealed extensive internal colonization of physiologically active roots by atypical fungal structures that appear to function as protoplasts, without a distinguishable wall or with very thin hyaline walls that escape detection by methods staining specifically for fungal chitin. These structures were presumed to be active fungal stages that progressed to form stained or melanized septate hyphae and microsclerotia characteristic of DSE fungi within dormant roots. The most conspicuous characteristic of these fungi were the unique associations that formed within sieve elements and the accumulation of massive quantities of lipids. This interface suggests a biologically significant location for carbon transfer between the plant and fungus. The continuous intimate association with all sieve elements, cortical and epidermal cells as well as external extension on the root surface and into the soil indicates that they are systemic and considerably more prevalent than previously thought. A fungal network associated with a mucilaginous complex observed on the root surface and its potential role in root function in dry soil is discussed. It is suggested that those fungi that non-pathogenically and totally colonize plant cells be classed as systemic endophytic fungi (SEF). This would refine the broad designation of DSE fungi. The potential mutualistic benefit of SEF for native plants in arid ecosystems based on the extent of lipid accumulation and its apparent distribution is discussed.

  10. Refractoriness in human atria

    DEFF Research Database (Denmark)

    Skibsbye, Lasse; Jespersen, Thomas; Christ, Torsten

    2016-01-01

    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. METHODS AND RESULTS: Steady......-state activation and inactivation parameters of sodium channels measured in vitro in isolated human atrial cardiomyocytes were used to parameterise a mathematical human atrial cell model. Action potential data were acquired from human atrial trabeculae of patients in either sinus rhythm or chronic atrial...... in pharmacological management of chronic atrial fibrillation....

  11. Occlusion of left atrial appendage in patients with atrial fibrillation

    Directory of Open Access Journals (Sweden)

    О. Н. Ганеева

    2015-10-01

    Full Text Available The article reviews a new method of prophylaxis of thromboembolitic complications, specifically occlusion of left atrial appendage, in patients with atrial fibrillation. Indications and contraindications for the procedure, as well as a step-by-step process of the intervention itself are described. Special emphasis is placed on the up-to-date evidence and the review of clinical trials.

  12. Left atrial appendage occlusion for stroke prevention in atrial fibrillation

    DEFF Research Database (Denmark)

    Tzikas, Apostolos; Shakir, Samera; Gafoor, Sameer;

    2015-01-01

    Aims: To investigate the safety, feasibility, and efficacy of left atrial appendage occlusion (LAAO) with the AMPLATZER Cardiac Plug (ACP) for stroke prevention in patients with atrial fibrillation (AF). Methods and results: Data from consecutive patients treated in 22 centres were collected...

  13. Abnormal atrial activation in young patients with lone atrial fibrillation

    DEFF Research Database (Denmark)

    Holmqvist, Fredrik; Olesen, Morten S; Tveit, Arnljot

    2011-01-01

    Aims Patients with a history of atrial fibrillation (AF) have previously been shown to have altered atrial conduction, as seen non-invasively using signal-averaged P-wave analysis. However, little is known about the P-wave morphology in patients in the early phases of AF with structurally normal ...

  14. Effect of hepatocyte growth factor and transforming growth factor-β1 on atrial fibroblasts fibrosis

    Institute of Scientific and Technical Information of China (English)

    张建成

    2012-01-01

    Objective To investigate the effect of hepatocyte growth factor (HGF) and transforming growth factor-β1 (TGFβ1) on the expression of α-smooth muscle actin(α-SMA) and collagen I in human atrial fibroblast in vitro, and to explore the possible molecular mechanism of atrial fibrosis in patients

  15. The role of atrial electrical remodeling in the progression of focal atrial ectopy to persistent atrial fibrillation

    NARCIS (Netherlands)

    Hobbs, WJC; Van Gelder, IC; Fitzpatrick, AP; Crijns, HJGM; Garratt, CJ

    1999-01-01

    Focal Atrial Fibrillation and Electrical Remodeling. Although atrial fibrillation- (AF) induced changes in atrial refractoriness (atrial electrical remodeling) have been demonstrated in a number of different animal models, the clinical significance of this process is unknown. We describe a patient i

  16. Effects of trimetazidine on atrial structural remodeling and platelet activation in dogs with atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    HAN Wei; LI Wei-min; ZHOU Hong-yan; HUO Hong; WEI Na; DONG Guo; CAO Yong; ZHOU Guo; YANG Shu-sen

    2009-01-01

    @@ Atrial fibrillation (AF) is one of the most common arrhythmias in clinical practice. AF results in electrophysiological alterations which involve increased atrial effective refractory period and atrial effective refractory period dispersion, reduced rate adaptation of atrial effective refractory period, and slowed atrial conduction.

  17. Total plasma proANP increases with atrial dilatation in horses

    DEFF Research Database (Denmark)

    Van Der Vekens, N; Hunter, I; Timm, A

    2015-01-01

    Equine atrial natriuretic peptide (ANP) plasma concentrations are correlated with left atrial size. However, species-specific assays are lacking and the results from human assays are poorly reproducible. A new methodology called processing independent analysis (PIA) that measures the total pro......ANP product in plasma has proven to be successful in human medicine, but has never been used in horses. The aims were to establish an equine proANP reference interval by measurement of the total proANP product using PIA and to examine the proANP concentrations in horses with atrial dilatation. Sample...... stability was studied by comparison of storage at -80°C and -20°C. Plasma samples were obtained from 23 healthy horses, 12 horses with moderate or severe valvular regurgitation without atrial dilatation and 42 horses with valvular regurgitation and atrial dilatation. The proANP concentration...

  18. Effects of a dark-septate endophytic isolate LBF-2 on the medicinal plant Lycium barbarum L.

    Science.gov (United States)

    Zhang, Hai-Han; Tang, Ming; Chen, Hui; Wang, Ya-Jun

    2012-02-01

    Dark septate endophytes (DSE) are ubiquitous root associated fungi; however, our understanding of their ecological function remains unclear. Here, we investigated the positive effect of a DSE fungus on its host plant Lycium barbarum L. A DSE isolate, LBF-2, isolated from the roots of L. barbarum, was inoculated onto the roots of plants, which were grown under greenhouse conditions for five weeks. The result of molecular analyses of internal transcribed spacer regions indicated that LBF-2 was 96% similar to Paraphoma chrysanthemicola. Melanized septate hyphae were observed in the root cortical cells of L. barbarum using a light microscope. Inoculation with LBF-2 increased the total biomass by 39.2% and also enhanced chlorophyll fluorescence. Inoculation increased the concentration of total chlorophyll by 22.8% and of chlorophyll a by 21.3%, relative to uninoculated controls. These data indicate that the LBF-2 isolate might be used to facilitate the cultivation of L. barbarum, which has medicinal applications.

  19. Atrial fibrillation: effects beyond the atrium?

    Science.gov (United States)

    Wijesurendra, Rohan S; Casadei, Barbara

    2015-03-01

    Atrial fibrillation (AF) is the most common sustained clinical arrhythmia and is associated with significant morbidity, mostly secondary to heart failure and stroke, and an estimated two-fold increase in premature death. Efforts to increase our understanding of AF and its complications have focused on unravelling the mechanisms of electrical and structural remodelling of the atrial myocardium. Yet, it is increasingly recognized that AF is more than an atrial disease, being associated with systemic inflammation, endothelial dysfunction, and adverse effects on the structure and function of the left ventricular myocardium that may be prognostically important. Here, we review the molecular and in vivo evidence that underpins current knowledge regarding the effects of human or experimental AF on the ventricular myocardium. Potential mechanisms are explored including diffuse ventricular fibrosis, focal myocardial scarring, and impaired myocardial perfusion and perfusion reserve. The complex relationship between AF, systemic inflammation, as well as endothelial/microvascular dysfunction and the effects of AF on ventricular calcium handling and oxidative stress are also addressed. Finally, consideration is given to the clinical implications of these observations and concepts, with particular reference to rate vs. rhythm control.

  20. Unraveling the role of dark septate endophyte (DSE) colonizing maize (Zea mays) under cadmium stress: physiological, cytological and genic aspects

    OpenAIRE

    Jun-ling Wang; Tao Li; Gao-yuan Liu; Joshua M. Smith; Zhi-wei Zhao

    2016-01-01

    A growing body of evidence suggests that plant root-associated fungi such as dark septate endophytes (DSE) can help plants overcome many biotic and abiotic stresses, of great interest is DSE-plant metal tolerance and alleviation capabilities on contaminated soils. However, the tolerance and alleviation mechanisms involved have not yet been elucidated. In the current study, the regulation and physiological response of Zea mays to its root-associated DSE, Exophiala pisciphila was analyzed under...

  1. Evidence for Biotrophic Lifestyle and Biocontrol Potential of Dark Septate Endophyte Harpophora oryzae to Rice Blast Disease

    OpenAIRE

    Zhen-Zhu Su; Li-Juan Mao; Na Li; Xiao-Xiao Feng; Zhi-Lin Yuan; Li-Wei Wang; Fu-Cheng Lin; Chu-Long Zhang

    2013-01-01

    The mutualism pattern of the dark septate endophyte (DSE) Harpophora oryzae in rice roots and its biocontrol potential in rice blast disease caused by Magnaporthe oryzae were investigated. Fluorescent protein-expressing H. oryzae was used to monitor the colonization pattern. Hyphae invaded from the epidermis to the inner cortex, but not into the root stele. Fungal colonization increased with root tissue maturation, showing no colonization in the meristematic zone, slight colonization in the e...

  2. The human adult cardiomyocyte phenotype

    NARCIS (Netherlands)

    Bird, SD; Doevendans, PA; van Rooijen, MA; de la Riviere, AB; Hassink, RJ; Passier, R; Mummery, CL

    2003-01-01

    Aim: Determination of the phenotype of adult human atrial and ventricular myocytes based on gene expression and morphology. Methods: Atrial and ventricular cardiomyocytes were obtained from patients undergoing cardiac surgery using a modified isolation procedure. Myocytes were isolated and cultured

  3. Effects of electrical and structural remodeling on atrial fibrillation maintenance: a simulation study.

    Science.gov (United States)

    Krogh-Madsen, Trine; Abbott, Geoffrey W; Christini, David J

    2012-01-01

    Atrial fibrillation, a common cardiac arrhythmia, often progresses unfavourably: in patients with long-term atrial fibrillation, fibrillatory episodes are typically of increased duration and frequency of occurrence relative to healthy controls. This is due to electrical, structural, and contractile remodeling processes. We investigated mechanisms of how electrical and structural remodeling contribute to perpetuation of simulated atrial fibrillation, using a mathematical model of the human atrial action potential incorporated into an anatomically realistic three-dimensional structural model of the human atria. Electrical and structural remodeling both shortened the atrial wavelength--electrical remodeling primarily through a decrease in action potential duration, while structural remodeling primarily slowed conduction. The decrease in wavelength correlates with an increase in the average duration of atrial fibrillation/flutter episodes. The dependence of reentry duration on wavelength was the same for electrical vs. structural remodeling. However, the dynamics during atrial reentry varied between electrical, structural, and combined electrical and structural remodeling in several ways, including: (i) with structural remodeling there were more occurrences of fragmented wavefronts and hence more filaments than during electrical remodeling; (ii) dominant waves anchored around different anatomical obstacles in electrical vs. structural remodeling; (iii) dominant waves were often not anchored in combined electrical and structural remodeling. We conclude that, in simulated atrial fibrillation, the wavelength dependence of reentry duration is similar for electrical and structural remodeling, despite major differences in overall dynamics, including maximal number of filaments, wave fragmentation, restitution properties, and whether dominant waves are anchored to anatomical obstacles or spiralling freely.

  4. Arbuscular Mycorrhizal and Dark Septate Endophyte Fungal Associations in South Indian Aquatic and Wetland Macrophytes

    Directory of Open Access Journals (Sweden)

    Kumar Seerangan

    2014-01-01

    Full Text Available Investigations on the prevalence of arbuscular mycorrhizal (AM and dark septate endophyte (DSE fungal symbioses are limited for plants growing in tropical aquatic and wetland habitats compared to those growing on terrestrial moist or dry habitats. Therefore, we assessed the incidence of AM and DSE symbiosis in 8 hydrophytes and 50 wetland plants from four sites in south India. Of the 58 plant species examined, we found AM and DSE fungal symbiosis in 21 and five species, respectively. We reported for the first time AM and DSE fungal symbiosis in seven and five species, respectively. Intermediate-type AM morphology was common, and AM morphology is reported for the first time in 16 plant species. Both AM and DSE fungal colonization varied significantly across plant species and sites. Intact and identifiable AM fungal spores occurred in root zones of nine plant species, but AM fungal species richness was low. Though no clear relationship between AM and DSE fungal colonization was recognized, a significant negative correlation between AM colonization and spore numbers was established. Our study suggests that the occurrence of AM and DSE fungal symbiosis in plants growing in hydrophytic and wetland habitats is not as common as in terrestrial habitats.

  5. Wetland dicots and monocots differ in colonization by arbuscular mycorrhizal fungi and dark septate endophytes.

    Science.gov (United States)

    Weishampel, Peter A; Bedford, Barbara L

    2006-10-01

    As an initial step towards evaluating whether mycorrhizas influence composition and diversity in calcareous fen plant communities, we surveyed root colonization by arbuscular mycorrhizal fungi (AMF) and dark septate endophytic fungi (DSE) in 67 plant species in three different fens in central New York State (USA). We found colonization by AMF and DSE in most plant species at all three sites, with the type and extent of colonization differing between monocots and dicots. On average, AMF colonization was higher in dicots (58+/-3%, mean+/-SE) than in monocots (13+/-4%) but DSE colonization followed the opposite trend (24+/-3% in monocots and 9+/-1% in dicots). In sedges and cattails, two monocot families that are often abundant in fens and other wetlands, AMF colonization was usually very low (<10%) in five species and completely absent in seven others. However, DSE colonization in these species was frequently observed. Responses of wetland plants to AMF and DSE are poorly understood, but in the fen communities surveyed, dicots appear to be in a better position to respond to AMF than many of these more abundant monocots (e.g., sedges and cattails). In contrast, these monocots may be more likely to respond to DSE. Future work directed towards understanding the response of these wetland plants to AMF and DSE should provide insight into the roles these fungal symbionts play in influencing diversity in fen plant communities.

  6. Do colonization by dark septate endophytes and elevated temperature affect pathogenicity of oomycetes?

    Science.gov (United States)

    Tellenbach, Christoph; Sieber, Thomas N

    2012-10-01

    Phialocephala subalpina is one of the most frequent dark septate root endophytes in tree roots but its function in forest ecosystems is largely unknown. A full-factorial infection experiment was performed, using six P. subalpina isolates, two pathogenic oomycetes (Phytophthora plurivora [syn. Phytophthora citricola s.l.] and Elongisporangium undulatum [syn. Pythium undulatum]) and two temperature regimes (17.9 and 21.6 °C) to examine the ability of P. subalpina to protect Norway spruce seedlings against root pathogens. Seedling survival, disease intensity and seedling growth were affected by P. subalpina genotype, temperature and pathogen species. Some P. subalpina isolates effectively reduced mortality and disease intensity caused by the two pathogens. Elevated temperature adversely affected seedling growth but did not aggravate the effect of the pathogens. Elongisporangium undulatum but not P. plurivora significantly reduced plant growth. Colonization density of P. subalpina measured by quantitative PCR was not affected by temperature or the presence of the pathogens. In conclusion, P. subalpina confers an indirect benefit to its host and might therefore be tolerated in natural ecosystems, despite negative effects on plant health and plant growth.

  7. Contrasting preferences of arbuscular mycorrhizal and dark septate fungi colonizing boreal and subarctic Avenella flexuosa.

    Science.gov (United States)

    Kauppinen, M; Raveala, K; Wäli, P R; Ruotsalainen, A L

    2014-04-01

    Arbuscular mycorrhizal (AM) and dark septate endophytic (DSE) fungi are ubiquitous in grass roots, but their colonizations may vary according to latitudinal gradient and site conditions. We investigated how vegetation zone (boreal vs. subarctic), humus thickness, and site openness affect root fungal colonizations of the grass Avenella flexuosa. More precisely, we hypothesized that AM and DSE fungal colonizations would have different responses to environmental conditions such that AM fungi could be more common in boreal zone, whereas we expected DSE fungi to be more affected by the amount of humus. We found site openness to affect AM and DSE fungi in a contrasting manner, in interaction with the vegetation zone. AM colonization was high at open coastal dunes, whereas DSE fungi were more common at forested sites, in the boreal zone. Humus thickness affected AM fungi negatively and DSE fungi positively. To conclude, the observed AM and DSE fungal colonization patterns were largely contrasting. AM fungi were favored in seashore conditions characterized by thin humus layer, whereas DSE fungi were favored in conditions of higher humus availability.

  8. Interaction between an isolate of dark-septate fungi and its host plant Saussurea involucrata.

    Science.gov (United States)

    Wu, Liqin; Guo, Shunxing

    2008-02-01

    A dark-septate endophytic (DSE) fungus EF-M was isolated from the roots of an alpine plant Saussurea involucrata Kar. et Kir. ex Maxim. The fungus was identified by sequencing the PCR-amplified rDNA 5.8S gene and ITS regions. The sequence was compared with similar sequences in the GenBank, and results showed that EF-M was congeneric to Leptodontidium. Resynthesis study was conducted to clarify the relationship between the root endophyte EF-M and the host plant S. involucrata using the material grown in sterile culture bottle. In roots recovered 6 weeks after inoculation, epidermal cells were colonized by intercellular and intracellular hyphae and "microsclerotia" formed within individual cells in the epidermis layers. However, hyphae did not invade the cortex and the stele. There were no profound effects of endophyte EF-M on plant root development, but significant differences were detected in plant height and shoot dry weight between the treatments. The present study is the first report hitherto on DSE fungi in S. involucrata.

  9. [Colonization of arbuscular mycorrhizal fungi and dark septate endophytes in Panax notoginseng].

    Science.gov (United States)

    Zhang, Zhihui; Chen, Di; Zhao, Dandan; Jin, Hang; Li, Lingfei

    2011-09-01

    Arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) colonizing Panax notoginseng in three main producing areas in Wenshan Prefecture of Yunan province were investigated. The fungal colonization of 144 roots samples including healthy and rot roots of P. notoginseng with different age were observed by means of acid fuchsin stain. The results showed that P. notoginseng was the typical arbuscular mycorrhizal plant. Although there was no significant difference in AMF and DSE colonization among three sites, the total colonization of AMF was significantly higher than that of DSE. Statistical analysis demonstrated that the fresh weight of P. notoginseng root was positively significantly correlated with the colonization of AMF, but not with the colonization of DSE. These results suggest that AMF may play more important role than DSE in improving the yield and quality of P. notoginseng. Furthermore, AMF colonization of healthy P. notoginseng was higher than that of plant with root rot, which suggested that AMF could defend P. notoginseng against root rot pathogens. AMF have great potentiality and broad prospect to control root rot of P. notoginseng.

  10. Arbuscular mycorrhizal associations and occurrence of dark septate endophytes in the roots of Brazilian weed plants.

    Science.gov (United States)

    Massenssini, André Marcos; Bonduki, Víctor Hugo Araújo; Tótola, Marcos Rogério; Ferreira, Francisco Affonso; Costa, Maurício Dutra

    2014-02-01

    The ecology of weed plants includes their interactions with soil microorganisms, such as mutualistic partners that may contribute to their adaptation and competitive success in the agricultural fields. Despite the importance of microorganisms to plant growth, knowledge on weed-symbiont associations is still incipient compared to crops. Thus, a survey for the presence of arbuscular mycorrhiza (AM) and dark septate endophyte (DSE) associations in the roots of 50 weed species was done in three distinct areas during the dry and rainy seasons. We found that 41 and 29 out of the 50 species were associated with AM fungi and DSE, respectively, and 27 species presented both associations. All the plant species not forming AM belong to families thought to be nonmycorrhizal, such as Amaranthaceae, Commelinaceae, Brassicaceae, and Cyperaceae. The most common morphotype of AM observed was the Arum-type. No significant differences were found in root length colonization between the areas or seasons. For 19 species surveyed, this is the first report on their mycorrhizal status.

  11. Occurrence of arbuscular mycorrhizas and dark septate endophytes in pteridophytes from a Patagonian rainforest, Argentina.

    Science.gov (United States)

    Fernández, Natalia Verónica; Messuti, María Inés; Fontenla, Sonia Beatriz

    2013-06-01

    Arbuscular mycorrhizas (AM) are one of the most widespread types of symbiotic associations. Pteridophytes occupy an important position in the evolution of vascular plants. However, their mycorrhizal state remains poorly understood. The aim of this work was to describe the general mycorrhizal status and the occurrence of dark septate endophytes (DSE) in the pteridophytic flora of a Valdivian temperate forest in Patagonia, Argentina. First, the roots of nine terrestrial species representing six families were examined, and this information was then compared with other surveys concerning the occurrence of AM in other pteridophytic species within the same Valdivian temperate forest. AM were recorded in 98.6% of the samples analyzed in this work and all of them corresponded to the Paris-type morphology. DSEs were also present within the roots of all terrestrial species. A comparison to published results in other ferns and lycophytes that have been studied in this Valdivian temperate forest (161 sporophytes, 21 species and 10 families) was made. Clear differences in colonization patterns between eusporangiate/leptosporangiate and epiphytic/terrestrial species became evident and are discussed.

  12. Tree species as hosts for arbuscular mycorrhizal and dark septate endophyte fungi

    Institute of Scientific and Technical Information of China (English)

    E.Uma; K.Sathiyadash; J.Loganathan; T.Muthukumar

    2012-01-01

    A survey of 35 tree species (belonging to 28 genera in 19families) in Aliyar,South India was carried out to ascertain their arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungal status.All the tree species examined had AM association.AM and DSE colonization is reported for the first time in 20 and 14 species respectively.Cooccurrence of AM and DSE was observed in 14 (40%) tree species.The extent of DSE colonization was inversely related to the extent of AM fungal colonization.Six tree species had Arum-type,18 had intermediatetype and 1l had typical Paris-type AM morphology.AM fungal spore morphotypes belonging to 11 species in two genera were isolated from the rhizosphere soil.AM fungal spore numbers were not related to the extent of AM colonization and Glomus dominated spore diversity.AM association individually and along with DSE were found respectively in the 63% and 44% of the economically important tree species.The occurrence of AM and DSE fungal association in economically important indigenous tree species indicates the possibility of exploiting this association in future conservation programmes of these species.

  13. Vacuolar localization of phosphorus in hyphae of Phialocephala fortinii, a dark septate fungal root endophyte.

    Science.gov (United States)

    Saito, Katsuharu; Kuga-Uetake, Yukari; Saito, Masanori; Peterson, R Larry

    2006-07-01

    Phialocephala fortinii is a dark septate fungal endophyte that colonizes roots of many host species. Its effect on plant growth varies from being pathogenic to beneficial. The basic biology of this species has received little research, and thus the main objectives of this study were to determine cytological features of hyphae, including the nature of the vacuolar system, and whether polyphosphate was present in vacuoles. Both living hyphae and hyphae that had been rapidly frozen and freeze substituted before embedding were studied. A complex system of vacuoles, including a motile tubular vacuolar system, elongated vacuoles, and spherical vacuoles, was demonstrated in living hyphae by the fluorescent probe Oregon Green 488 carboxylic acid diacetate, using laser scanning confocal microscopy. The motile tubular vacuolar system was more prevalent at the hyphal tip than in more distal regions, whereas elongated vacuoles and spherical vacuoles were more abundant distal to the tip. All vacuoles contained polyphosphate as shown by labelling embedded samples with recombinant polyphosphate binding domain of Escherichia coli exopolyphosphatase, containing Xpress tag at the N-terminal end, followed by anti-Xpress antibody and a secondary antibody conjugated either to a fluorescent probe for laser scanning confocal microscopy or colloidal gold for transmission electron microscopy. The polyphosphate was dispersed in vacuoles. This was confirmed by staining embedded samples with 4',6-diamidino-2-phenylindole and viewing with UV light using epifluorescence microscopy. These cytological methods showed that the tubular vacuolar system had lower concentrations of polyphosphate than the spherical vacuoles. Lipid bodies were present around vacuoles.

  14. Pseudosigmoidea ibarakiensis sp. nov., a dark septate endophytic fungus from a cedar forest in Ibaraki, Japan.

    Science.gov (United States)

    Diene, Ousmane; Wang, Wei; Narisawa, Kazuhiko

    2013-01-01

    A dark septate fungus of Pseudosigmoidea, Hyphomycetes, was recovered from forest soil in Ibaraki prefecture, Japan. The isolate is characterized by pale to brown conidia with up to 8 septa measuring 68-132 × 4-7.9 mm. It is also unique in producing conidia borne by long conidogenious cells in agar medium with or without water, compared to P. cranei, which must be immersed in water to sporulate. Morphological analysis indicated that the isolate is distinct from P. cranei and is described as a new species, P. ibarakiensis sp. nov. Pathogenicity tests of Chinese cabbage and cucumber seedlings indicated that the fungus grows as an endophyte and colonizes, inter and intracellularly, the root epidermal and cortical layers without causing apparent disease symptoms in the host. This endophyte showed the ability to support cucumber plant growth under conditions where NaNO3 was replaced by organic nitrogen but also conferred to Chinese cabbage the ability to grow at low pH. It also became successfully established in six other plants, including the Brassicae, Solanaceae, Poaceae, and Liliacea families, suggesting its adaptability to a broad range of host plants.

  15. A meta-analysis of plant responses to dark septate root endophytes.

    Science.gov (United States)

    Newsham, K K

    2011-05-01

    • Dark septate endophytes (DSE) frequently colonize roots in the natural environment, but the effects of these fungi on plants are obscure, with previous studies indicating negative, neutral or positive effects on plant performance. • In order to reach a consensus for how DSE influence plant performance, meta-analyses were performed on data from 18 research articles, in which plants had been inoculated with DSE in sterile substrates. • Negative effects of DSE on plant performance were not recorded. Positive effects were identified on total, shoot and root biomass, and on shoot nitrogen (N) and phosphorus contents, with increases of 26-103% in these parameters for plants inoculated with DSE, relative to uninoculated controls. Inoculation increased total, shoot and root biomass by 52-138% when plants had not been supplied with additional inorganic N, or when all, or the majority, of N was supplied in organic form. Inoculation with the DSE Phialocephala fortinii was found to increase shoot and root biomass, shoot P concentration and shoot N content by 44-116%, relative to uninoculated controls. • The analyses here suggest that DSE enhance plant performance under controlled conditions, particularly when all, or the majority, of N is available in organic form.

  16. Characterization of the interaction between the dark septate fungus Phialocephala fortinii and Asparagus officinalis roots.

    Science.gov (United States)

    Yu, T; Nassuth, A; Peterson, R L

    2001-08-01

    Phialocephala fortinii Wang & Wilcox is a member of root-inhabiting fungi known collectively as dark septate endophytes (DSE). Although very common and distributed worldwide, few studies have documented their interaction with roots on a structural basis. The objective of this study was to determine the early colonization events and formation of microsclerotia of P. fortinii in roots of Asparagus officinalis L., a species known to have DSE. A loose network of hyphae accumulated at the root surface, and coils formed around root hairs and external to epidermal cells overlying short cells of the dimorphic, suberized exodermis. Root penetration occurred via swollen, appressorium-like structures into epidermal cells where coiling of hyphae occurred along the periphery of the cells. Hyphae penetrated from the epidermis into short exodermal cells and from these into cortical cells. Hyphae colonized the cortex up to the endodermis and sometimes entered the vascular cylinder. Some root tips were colonized as well. Microsclerotia in epidermal and exodermal short cells accumulated glycogen, protein, and polyphosphate. Energy-dispersive X-ray spectroscopy on distinct bodies visible in microsclerotial hyphae revealed high levels of phosphorus.

  17. Septate uterus with cervical duplication and a longitudinal vaginal septum: an unclassified mullerian anomaly

    Directory of Open Access Journals (Sweden)

    Ruchika Mangla

    2016-02-01

    Full Text Available Uterine anomalies are the result of disturbances in the development, formation or fusion of the mullerian ducts during foetal life with an incidence of 0.001%-10% in general population. These patients most often present with amenorrhoea, dysmenorrhoea, dyspareunia and infertility. Women with these anomalies are more prone to poor foetal outcomes such as first trimester losses or preterm labour. We report a case of a 35 years old female with septate uterus with cervical duplication and a longitudinal vaginal septum. Diagnosis was obtained by physical examination, ultrasound imaging, hysterosalphingography and magnetic resonance imaging and hysterolaproscopy. The clinical presentation of such a case and surgical options available were studied, and the excision of the vaginal septum was done. This case of congenital uterine anomaly does not fit into the current classification system of mullerian anomalies by American fertility society, which is based on the traditional caudal to cranial, unidirectional developmental pattern. This strongly indicates the possibility of an alternative mechanism of mullerian development. [Int J Reprod Contracept Obstet Gynecol 2016; 5(2.000: 536-538

  18. Atrial fibrillation and heart failure: is atrial fibrillation a disease?

    Science.gov (United States)

    Tilman, V

    2014-09-01

    Atrial fibrillation in heart failure often occur together. The relationship between atrial fibrillation and heart failure has remained a subject of research. The main manifestation of the violation of hydrodynamics in heart failure is the increased end-diastolic pressure, which is transmitted through the intercommunicated system (left ventricle-left atrium-pulmonary veins-alveolar capillaries) causing increased pulmonary wedge pressure with the danger for pulmonary edema. End-diastolic pressure is the sum of left ventricle diastolic pressure and left atrial systolic pressure. Stopping the mechanical systole of the left atrium can reduce the pressure in the system in heart failure. Atrial fibrillation stops the mechanical systole of the left atrium and decreases the intercommunicating pressure and pulmonary wedge pressure. It is possible that atrial fibrillation is a mechanism for protection from increasing end-diastolic pressure and pulmonary wedge pressure, and prevents the danger of pulmonary edema. This hypothesis may explain the relationship between heart failure and atrial fibrillation and their frequent association.

  19. [Nosology and mechanism of monomorphous atrial tachycardia].

    Science.gov (United States)

    Puech, P

    1990-12-01

    Monomorphous atrial tachycardias have been classified taking into account the ectopic rhythm rate, atrial wave morphology, the mode of activation of the atrial studied by endocavitary cartography, stimulation tests and their natural history. Atrial flutter is a right intra-atrial macroreentry of anticlockwise (common flutter) or clockwise (atypical flutter) rotation, maintained by anisotropic conduction around two pivotal zones located at the posterior and inferior part of the atrium. Tachycardia is made possible by the existence of an excitable zone on the circuit. Paroxysmal atrial tachycardias are far more often linked to localised reentry (sino-atrial or intra-atrial microreentry) than to provoked activity, stimulation tests enabling the distinction to be made. "Digitalis tachycardias" must be seen in the context of activity induced by late post-potential. Focal atrial tachycardias linked to ectopic automatism are a separate entity. They follow a chronic course in the young individual and may lead to a cardiomyopathy purely due to the rhythm abnormality.

  20. Atrial Electrophysiological Remodeling and Fibrillation in Heart Failure

    Science.gov (United States)

    Pandit, Sandeep V.; Workman, Antony J.

    2016-01-01

    Heart failure (HF) causes complex, chronic changes in atrial structure and function, which can cause substantial electrophysiological remodeling and predispose the individual to atrial fibrillation (AF). Pharmacological treatments for preventing AF in patients with HF are limited. Improved understanding of the atrial electrical and ionic/molecular mechanisms that promote AF in these patients could lead to the identification of novel therapeutic targets. Animal models of HF have identified numerous changes in atrial ion currents, intracellular calcium handling, action potential waveform and conduction, as well as expression and signaling of associated proteins. These studies have shown that the pattern of electrophysiological remodeling likely depends on the duration of HF, the underlying cardiac pathology, and the species studied. In atrial myocytes and tissues obtained from patients with HF or left ventricular systolic dysfunction, the data on changes in ion currents and action potentials are largely equivocal, probably owing mainly to difficulties in controlling for the confounding influences of multiple variables, such as patient’s age, sex, disease history, and drug treatments, as well as the technical challenges in obtaining such data. In this review, we provide a summary and comparison of the main animal and human electrophysiological studies to date, with the aim of highlighting the consistencies in some of the remodeling patterns, as well as identifying areas of contention and gaps in the knowledge, which warrant further investigation. PMID:27812293

  1. Idiopathic giant right atrial aneurysm

    Science.gov (United States)

    Uppu, Santosh C; Sachdeva, Ritu; Imamura, Michiaki

    2013-01-01

    A 2-year-old boy with an incidental finding of massive cardiomegaly on a chest X-ray was diagnosed with a giant right atrial aneurysm upon further investigation with echocardiography. The patient underwent successful surgical reduction of the right atrium and closure of the patent foramen ovale to prevent thromboembolic complications and to lower the risk of atrial arrhythmias. The resected atrium had paper-thin walls and pathological features of interstitial fibrosis with endocardial thickening. PMID:23626440

  2. Idiopathic giant right atrial aneurysm

    OpenAIRE

    Uppu, Santosh C; Ritu Sachdeva; Michiaki Imamura

    2013-01-01

    A 2-year-old boy with an incidental finding of massive cardiomegaly on a chest X-ray was diagnosed with a giant right atrial aneurysm upon further investigation with echocardiography. The patient underwent successful surgical reduction of the right atrium and closure of the patent foramen ovale to prevent thromboembolic complications and to lower the risk of atrial arrhythmias. The resected atrium had paper-thin walls and pathological features of interstitial fibrosis with endocardial thicken...

  3. Idiopathic giant right atrial aneurysm

    Directory of Open Access Journals (Sweden)

    Santosh C Uppu

    2013-01-01

    Full Text Available A 2-year-old boy with an incidental finding of massive cardiomegaly on a chest X-ray was diagnosed with a giant right atrial aneurysm upon further investigation with echocardiography. The patient underwent successful surgical reduction of the right atrium and closure of the patent foramen ovale to prevent thromboembolic complications and to lower the risk of atrial arrhythmias. The resected atrium had paper-thin walls and pathological features of interstitial fibrosis with endocardial thickening.

  4. Neovascularization in Left Atrial Myxoma

    Science.gov (United States)

    Dubey, Laxman; Chaurasia, Amit Kumar

    2012-01-01

    Abstract We report a case with a left atrial mass who underwent coronary angiography to rule out coronary artery disease. Coronary angiography revealed an anomalous tortuous vascular structure originating from the left circumflex coronary artery to the left atrial tumor suggestive of neovascularization. Preoperative coronary angiography is useful for coronary artery evaluation and also provides additional information regarding the feeding vessel supplying the mass. PMID:24757609

  5. Comparative study of atrial fibrillation and AV conduction in mammals

    NARCIS (Netherlands)

    Meijler, F.L.; Tweel, I. van der

    1987-01-01

    Atrial fibrillation is one ofthe most common cardiac arrhythmias in humans. It a1so occurs quite frequent1y in dogs and horses. Comparative study of this arrhythmia may contribute to better understanding of the pathophysiologica1 mechanisms involved. In this study, we present a quantitative analysis

  6. Probucol attenuates atrial autonomic remodeling in a canine model of atrial fibrillation produced by prolonged atrial pacing

    Institute of Scientific and Technical Information of China (English)

    GONG Yong-tai; LI Wei-min; LI Yue; YANG Shu-sen; SHENG Li; YANG Ning; SHAN Hong-bo; XUE Hong-jie; LIU Wei; YANG Bao-feng; DONG De-li; LI Bao-xin

    2009-01-01

    Background We hypothesize that increased atrial oxidative stress and inflammation may play an important role in atrial nerve sprouting and heterogeneous sympathetic hyperinnervation during atrial fibrillation (AF). To test the hypothesis, we examined whether the antioxidant and anti-inflammatory treatment with probucol attenuates atrial autonomic remodeling in a canine model of AF produced by prolonged rapid right atrial pacing. Methods Twenty-one dogs were divided into a sham-operated group, a control group and a probucol group. Dogs in the control group and probucol group underwent right atrial pacing at 400 beats per minute for 6 weeks, and those in the probucol group received probucol 1 week before rapid atrial pacing until pacing stopped. After 6-week rapid atrial pacing, general properties including left atrial structure and function, atrial hemodynamics and the inducibility and duration of AF were measured in all the groups. Atrial oxidative stress markers and serum C-reactive protein (CRP) concentration were estimated. The degree of nerve sprouting and sympathetic innervation at the right atrial anterior wall (RAAW) and the left atrial anterior wall (LAAW) were quantified by immunohistochemistry, atdal norepinephrine contents were also detected. Atrial beta-nerve growth factor (beta-NGF) mRNA and protein expression at the RAAW and LAAW were assessed by real-time quantitative RT-PCR and Western blotting respectively. Results Atrial tachypacing induced significant nerve sprouting and heterogeneous sympathetic hyperinnervation, and the magnitude of nerve sprouting and hyperinnervation was higher in the RAAW than in the LAAW. Atrial beta-NGF mRNA and protein levels were significantly increased at the RAAW and LAAW, and the upregulation of beta-NGF expression was greater at the RAAW than at the LAAW in the control group. The beta-NGF protein level was positively correlated with the density of sympathetic nerves in all groups. Probucol decreased the increase of

  7. Plasma atrial natriuretic peptide and spontaneous diuresis in sick neonates.

    OpenAIRE

    Kojima, T; Hirata, Y; Fukuda, Y; Iwase, S.; Kobayashi, Y.

    1987-01-01

    Plasma concentrations of immunoreactive human atrial natriuretic peptide (human ANP) were sequentially determined in 12 infants with respiratory distress syndrome (RDS) or meconium aspiration syndrome (MAS) during various phases of diuresis to elucidate the role of human ANP in the occurrence of spontaneous diuresis in the newborn. Plasma immunoreactive ANP concentrations during the diuretic as well as the maximum diuretic phase were significantly (p less than 0.001) higher than during the pr...

  8. Left atrial electrophysiologic feature specific for the genesis of complex fractionated atrial electrogram during atrial fibrillation.

    Science.gov (United States)

    Hoshiyama, Tadashi; Yamabe, Hiroshige; Koyama, Junjiroh; Kanazawa, Hisanori; Ogawa, Hisao

    2016-05-01

    Complex fractionated atrial electrogram (CFAE) has been suggested to contribute to the maintenance of atrial fibrillation (AF). However, electrophysiologic characteristics of the left atrial myocardium responsible for genesis of CFAE have not been clarified. Non-contact mapping of the left atrium was performed at 37 AF onset episodes in 24 AF patients. Electrogram amplitude, width, and conduction velocity were measured during sinus rhythm, premature atrial contraction (PAC) with long- (L-PAC), short- (S-PAC) and very short-coupling intervals (VS-PAC). These parameters were compared between CFAE and non-CFAE regions. Unipolar electrogram amplitude was higher in CFAE than non-CFAE during sinus rhythm, L-, S- and VS-PAC (1.82 ± 0.73 vs. 1.13 ± 0.38, p genesis of CFAE.

  9. Late atypical atrial flutter after ablation of atrial fibrillation.

    Science.gov (United States)

    Ferreira, Raquel; Primo, João; Adão, Luís; Gonzaga, Anabela; Gonçalves, Helena; Santos, Rui; Fonseca, Paulo; Santos, José; Gama, Vasco

    2016-10-01

    Cardiac surgery for structural heart disease (often involving the left atrium) and radiofrequency catheter ablation of atrial fibrillation have led to an increased incidence of regular atrial tachycardias, often presenting as atypical flutters. This type of flutter is particularly common after pulmonary vein isolation, especially after extensive atrial ablation including linear lesions and/or defragmentation. The authors describe the case of a 51-year-old man, with no relevant medical history, referred for a cardiology consultation in 2009 for paroxysmal atrial fibrillation. After failure of antiarrhythmic therapy, he underwent catheter ablation, with criteria of acute success. Three years later he again suffered palpitations and atypical atrial flutter was documented. The electrophysiology study confirmed the diagnosis of atypical left flutter and reappearance of electrical activity in the right inferior pulmonary vein. This vein was again ablated successfully and there has been no arrhythmia recurrence to date. In an era of frequent catheter ablation it is essential to understand the mechanism of this arrhythmia and to recognize such atypical flutters.

  10. The response of dark septate endophytes (DSE) to heavy metals in pure culture.

    Science.gov (United States)

    Ban, Yihui; Tang, Ming; Chen, Hui; Xu, Zhouying; Zhang, Haihan; Yang, Yurong

    2012-01-01

    Dark septate endophytes (DSE) occur widely in association with plants exposed to heavy metal stress. However, little is known about the response of DSE exposed to heavy metals. In this study, five DSE were isolated from the roots of Astragalus adsurgens Pall. seedlings growing on lead-zinc mine tailings in China. Based on morphological characteristics and DNA sequence analyses, the isolates were identified as Gaeumannomyces cylindrosporus, Paraphoma chrysanthemicola, Phialophora mustea, Exophiala salmonis, and Cladosporium cladosporioides. G. cylindrosporus was selected to explore responses to Pb stress. Scanning electron microscopic observations of G. cylindrosporus grown on solid medium revealed curling of hyphae and formation of hyphal coils in response to Pb. In contrast, in liquid medium, hyphae became thick and swollen with an increase in Pb (II) concentration. We interpret that these changes are related to the variation in cell wall components. We also demonstrated that fungal melanin content increased with the addition of Pb(II). Melanin, as an important component in the cell wall, is known to be an essential antioxidant responsible for decreasing heavy metal toxicity. We also measured the total soluble protein content and glutathione (GSH) concentrations in G. cylindrosporus and found that they initially increased and then decreased with the increase of Pb(II) concentrations. The antioxidant enzyme activities were also examined, and the results showed that superoxide dismutase (SOD) activity was significantly positively correlated with Pb(II) concentrations (r = 0.957, P<0.001). Collectively, our observations indicate that the intracellular antioxidant systems, especially fungal melanin, play an important role in abating the hazards of heavy metals.

  11. The response of dark septate endophytes (DSE to heavy metals in pure culture.

    Directory of Open Access Journals (Sweden)

    Yihui Ban

    Full Text Available Dark septate endophytes (DSE occur widely in association with plants exposed to heavy metal stress. However, little is known about the response of DSE exposed to heavy metals. In this study, five DSE were isolated from the roots of Astragalus adsurgens Pall. seedlings growing on lead-zinc mine tailings in China. Based on morphological characteristics and DNA sequence analyses, the isolates were identified as Gaeumannomyces cylindrosporus, Paraphoma chrysanthemicola, Phialophora mustea, Exophiala salmonis, and Cladosporium cladosporioides. G. cylindrosporus was selected to explore responses to Pb stress. Scanning electron microscopic observations of G. cylindrosporus grown on solid medium revealed curling of hyphae and formation of hyphal coils in response to Pb. In contrast, in liquid medium, hyphae became thick and swollen with an increase in Pb (II concentration. We interpret that these changes are related to the variation in cell wall components. We also demonstrated that fungal melanin content increased with the addition of Pb(II. Melanin, as an important component in the cell wall, is known to be an essential antioxidant responsible for decreasing heavy metal toxicity. We also measured the total soluble protein content and glutathione (GSH concentrations in G. cylindrosporus and found that they initially increased and then decreased with the increase of Pb(II concentrations. The antioxidant enzyme activities were also examined, and the results showed that superoxide dismutase (SOD activity was significantly positively correlated with Pb(II concentrations (r = 0.957, P<0.001. Collectively, our observations indicate that the intracellular antioxidant systems, especially fungal melanin, play an important role in abating the hazards of heavy metals.

  12. Red list plants: colonization by arbuscular mycorrhizal fungi and dark septate endophytes.

    Science.gov (United States)

    Fuchs, B; Haselwandter, K

    2004-08-01

    Since information concerning the mycorrhization of endangered plants is of major importance for their potential re-establishment, we determined the mycorrhizal status of Serratula tinctoria (Asteraceae), Betonica officinalis (Lamiaceae), Drosera intermedia (Droseraceae) and Lycopodiella inundata (Lycopodiaceae), occurring at one of two wetland sites (fen meadow and peat bog), which differed in soil pH and available P levels. Root colonization by arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) was quantified. Colonization by AMF appeared to be more frequent in the fen meadow than in the peat bog, and depended on the host plant. Roots of S. tinctoria and B. officinalis were well colonized by AMF in the fen meadow (35-55% root length) and both arbuscules and vesicles were observed to occur in spring as well as in autumn. In the peat bog, L. inundata showed a low level of root colonization in spring, when vesicles were found frequently but no arbuscules. In roots of D. intermedia from the peat bog, arbuscules and vesicles were observed, but AMF colonization was lower than in L. inundata. In contrast, the amount of AMF spores extracted from soil at the peat bog site was higher than from the fen meadow soil. Spore numbers did not differ between spring and autumn in the fen meadow, but they were higher in spring than in autumn in the peat bog. Acaulospora laevis or A. colossica and Glomus etunicatum were identified amongst the AMF spores extracted from soil at the two sites. S. tinctoria and B. officinalis roots were also regularly colonized by DSE (18-40% root length), while L. inundata was only rarely colonized and D. intermedia did not seem to be colonized by DSE at all.

  13. Septate endophyte colonization and host responses of grasses and forbs native to a tallgrass prairie.

    Science.gov (United States)

    Mandyam, Keerthi; Fox, Chad; Jumpponen, Ari

    2012-02-01

    Native tallgrass prairies support distinct dark septate endophyte (DSE) communities exemplified by Periconia macrospinosa and Microdochium sp. that were recently identified as common root symbionts in this system. Since these DSE fungi were repeatedly isolated from grasses and forbs, we aimed to test their abilities to colonize different hosts. One Microdochium and three Periconia strains were screened for colonization and growth responses using five native grasses and six forbs in an in vitro system. Previously published data for an additional grass (Andropogon gerardii) were included and reanalyzed. Presence of indicative inter- and intracellular structures (melanized hyphae, microsclerotia, and chlamydospores) demonstrated that all plant species were colonized by the DSE isolates albeit to varying degrees. Microscopic observations suggested that, compared to forbs, grasses were colonized to a greater degree in vitro. Host biomass responses varied among the host species. In broad comparisons, more grass species than forbs tended to respond positively to colonization, whereas more forb species tended to be non-responsive. Based on the suspected differences in the levels of colonization, we predicted that tallgrass prairie grasses would support greater DSE colonization than forbs in the field. A survey of field-collected roots from 15 native species supported this hypothesis. Our study supports the "broad host range" of DSE fungi, although the differences in the rates of colonization in the laboratory and in the field suggest a greater compatibility between grasses and DSE fungi. Furthermore, host responses to DSE range from mutualism to parasitism, suggesting a genotype-level interplay between the fungi and their hosts that determines the outcome of this symbiosis.

  14. Sex in the PAC: A hidden affair in dark septate endophytes?

    Directory of Open Access Journals (Sweden)

    Duò Angelo

    2011-09-01

    Full Text Available Abstract Background Fungi are asexually and sexually reproducing organisms that can combine the evolutionary advantages of the two reproductive modes. However, for many fungi the sexual cycle has never been observed in the field or in vitro and it remains unclear whether sexual reproduction is absent or cryptic. Nevertheless, there are indirect approaches to assess the occurrence of sex in a species, such as population studies, expression analysis of genes involved in mating processes and analysis of their selective constraints. The members of the Phialocephala fortinii s. l. - Acephala applanata species complex (PAC are ascomycetes and the predominant dark septate endophytes that colonize woody plant roots. Despite their abundance in many ecosystems of the northern hemisphere, no sexual state has been identified to date and little is known about their reproductive biology, and how it shaped their evolutionary history and contributes to their ecological role in forest ecosystems. We therefore aimed at assessing the importance of sexual reproduction by indirect approaches that included molecular analyses of the mating type (MAT genes involved in reproductive processes. Results The study included 19 PAC species and > 3, 000 strains that represented populations from different hosts, continents and ecosystems. Whereas A. applanata had a homothallic (self-fertile MAT locus structure, all other species were structurally heterothallic (self-sterile. Compatible mating types were observed to co-occur more frequently than expected by chance. Moreover, in > 80% of the populations a 1:1 mating type ratio and gametic equilibrium were found. MAT genes were shown to evolve under strong purifying selection. Conclusions The signature of sex was found in worldwide populations of PAC species and functionality of MAT genes is likely preserved by purifying selection. We hypothesize that cryptic sex regularely occurs in the PAC and that further field studies and in

  15. Isolated Atrial Amyloidosis in Patients with Various Types of Atrial Fibrillation.

    Science.gov (United States)

    Sukhacheva, T V; Eremeeva, M V; Ibragimova, A G; Vaskovskii, V A; Serov, R A; Revishvili, A Sh

    2016-04-01

    The myocardium of the right and left atrial appendages (auricles) in patients with paroxysmal, persistent, and permanent forms of atrial fibrillation was examined by histological methods and electron microscopy. Isolated atrial amyloidosis was detected in the left (50.0-56.3% patients) and in the right (45.0-55.6% patients) atrial appendages. In all cases, immunohistochemistry revealed atrial natriuretic peptide in fibrillary amyloid deposits. Ultrastructurally, amyloid masses formed clusters of myofibrils 8-10 nm in diameter. They were chaotically located in the extracellular space along the sarcolemma as well as in membrane invaginations, dilated tubules of cardiomyocyte T-tubular system, and vascular walls. Amyloidosis was predominantly observed in women; its degree positively correlated with age of patients and duration of atrial fibrillation but negatively correlated with atrial fibrosis. The study revealed positive (in permanent atrial fibrillation) and negative (in paroxysmal atrial fibrillation) correlation of amyloidosis with myofibril content in atrial cardiomyocytes.

  16. Left Atrial Linear Ablation of Paroxysmal Atrial Fibrillation Guided by Three-dimensional Electroanatomical System

    DEFF Research Database (Denmark)

    Zhang, Dai-Fu; Li, Ying; Qi, Wei-Gang

    2005-01-01

    Objective To investigate the safety and efficacy of Left atrial linear ablation of paroxysmal atrial fibrillation guided by three-dimensional electroanatomical system. Methods 29 patients with paroxysmal atrial fibrillation in this study. A nonfluoroscopic mapping system was used to generate a 3D...... attacks unchanged. No pulmonary vein narrowing was observed. Conclusion Left atrial linear ablation of paroxysmal atrial fibrillation guided by three-dimensional electroanatomical system was safe and effective....

  17. RELATION BETWEEN LEFT ATRIAL SIZE AND ATRIAL FIBRILLATION IN DIFFERENT DISEASES

    Directory of Open Access Journals (Sweden)

    Rajith

    2014-11-01

    Full Text Available BACKGROUND: Atrial fibrillation is the most common cardiac dysrhythmia and left atrial size is an important factor in the development of atrial fibrillation. In the presence of atrial fibrillation an increase in left atrial size is associated with increased risk of stroke as well as increased morbidity and mortality. In this context, this study entitled “relation between left atrial size and atrial fibrillation in different diseases” was undertaken to study the left atrial size in different diseases causing atrial fibrillation and its relation to the atrial fibrillation. METHODS: A cross-sectional study was done from March 2004 to February 2006 in all medical units of Basaveshwar teaching and general hospital and Government general hospital Gulbarga. 70 cases of atrial fibrillation were studied in the present study. RESULTS: In the present study Atrial Fibrillation was common in >40 years age group (70%, left atrial enlargement was also more common in this age group (69.38%. Left atrial enlargement was seen in 70% of patients with Atrial Fibrillation. Rheumatic heart disease was the most common cause of Atrial Fibrillation (54.28% and left atrial enlargement was seen in 92% of these patients with mean left atrial size of 58.92 mm. Next most common cause was coronary artery disease (20% and left atrial enlargement was seen in 57.14% patients with a mean left atrial size of 39.5 mm. Left atrial size was normal in patients with thyrotoxicosis, congenital heart disease, lone Atrial Fibrillation and primary pulmonary hypertension. Left atrial enlargement was significantly associated with worsening of functional status (p<0.01, pulmonary arterial hypertension (p<0.005 and congestive cardial failure (p<0.02. 17.14% of patients with Atrial Fibrillation had embolic complications like stroke, of them left atrial enlargement was seen in 83.33% patients. 4.27% of patients with Atrial Fibrillation died during the hospital course, of them left atrial

  18. Low atrial septum pacing in pacemaker patients

    NARCIS (Netherlands)

    Voogt, Willem Gijsbert de

    2006-01-01

    In patients with an indication for anti bradycardia pacing, atrial fibrillation (AF) is a common arrhythmia (30-50%) even in the absence of atrial tachy arrhythmias before pacemaker implantation. Pace prevention and pace intervention for atrial tachy arrhythmias could be an interesting adjuvant trea

  19. Low atrial septum pacing in pacemaker patients

    NARCIS (Netherlands)

    Voogt, Willem Gijsbert de

    2006-01-01

    In patients with an indication for anti bradycardia pacing, atrial fibrillation (AF) is a common arrhythmia (30-50%) even in the absence of atrial tachy arrhythmias before pacemaker implantation. Pace prevention and pace intervention for atrial tachy arrhythmias could be an interesting adjuvant

  20. Successful pregnancy in each half uterus cavity of the septate uterus after transferring three embryos in one half-cavity: a case report.

    Science.gov (United States)

    Guo, Xiaoqiao; Sun, Xiaofang; Xu, Haiyan; Si, Shasha; Yu, Bolan; Liu, Jianqiao

    2013-08-07

    The incidence of Müllerian duct anomalies in women is rare, associating with urinary tract anomalies such as horseshoe or pelvic kidney, renal agenesis, duplication of the collecting system, or ectopic uterus. Septate uterus is one type of congenital uterine anomalies, in which there is a septum from the fundus to the cervix. Currently, it is believed that hysteroscopic metroplasty is a leading choice for patients if their recurrent spontaneous abortion is resulted from septate uterus. But, some people refuse to have a surgery, and successfully delivery. In this case report, we report a successful pregnancy with two gestational sacs, one in each half-cavity, in a woman with septate uterus after transfer of three embryos into one half-cavity. Finally, the women gave birth to two healthy babies in our hospital.

  1. Oxidative stress and inflammation as central mediators of atrial fibrillation in obesity and diabetes.

    Science.gov (United States)

    Karam, Basil S; Chavez-Moreno, Alejandro; Koh, Wonjoon; Akar, Joseph G; Akar, Fadi G

    2017-09-29

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in humans. Several risk factors promote AF, among which diabetes mellitus has emerged as one of the most important. The growing recognition that obesity, diabetes and AF are closely intertwined disorders has spurred major interest in uncovering their mechanistic links. In this article we provide an update on the growing evidence linking oxidative stress and inflammation to adverse atrial structural and electrical remodeling that leads to the onset and maintenance of AF in the diabetic heart. We then discuss several therapeutic strategies to improve atrial excitability by targeting pathways that control oxidative stress and inflammation.

  2. Total plasma proANP increases with atrial dilatation in horses.

    Science.gov (United States)

    Van Der Vekens, N; Hunter, I; Timm, A; Decloedt, A; De Clercq, D; Deprez, P; Goetze, J P; van Loon, G

    2015-12-19

    Equine atrial natriuretic peptide (ANP) plasma concentrations are correlated with left atrial size. However, species-specific assays are lacking and the results from human assays are poorly reproducible. A new methodology called processing independent analysis (PIA) that measures the total proANP product in plasma has proven to be successful in human medicine, but has never been used in horses. The aims were to establish an equine proANP reference interval by measurement of the total proANP product using PIA and to examine the proANP concentrations in horses with atrial dilatation. Sample stability was studied by comparison of storage at -80°C and -20°C. Plasma samples were obtained from 23 healthy horses, 12 horses with moderate or severe valvular regurgitation without atrial dilatation and 42 horses with valvular regurgitation and atrial dilatation. The proANP concentration was significantly (Phorses with atrial dilatation (761.4 (442.1-1859.1) pmol/l) than in healthy horses (491.6 (429.5-765.9) pmol/l; Phorses with cardiac disease but without atrial dilatation (544.4 (457.0-677.6) pmol/l). A cut-off value (573.8 pmol/l) for detection of atrial dilatation was calculated. Sample storage at -80°C did not differ from sample storage at -20°C. The measurement of total proANP in plasma detects atrial dilatation in horses and may be useful for clinical evaluation in equine medicine.

  3. Atrial fibrillation and delayed gastric emptying.

    Directory of Open Access Journals (Sweden)

    Isadora C Botwinick

    Full Text Available BACKGROUND: Atrial fibrillation and delayed gastric emptying (DGE are common after pancreaticoduodenectomy. Our aim was to investigate a potential relationship between atrial fibrillation and DGE, which we defined as failure to tolerate a regular diet by the 7(th postoperative day. METHODS: We performed a retrospective chart review of 249 patients who underwent pancreaticoduodenectomy at our institution between 2000 and 2009. Data was analyzed with Fisher exact test for categorical variables and Mann-Whitney U or unpaired T-test for continuous variables. RESULTS: Approximately 5% of the 249 patients included in the analysis experienced at least one episode of postoperative atrial fibrillation. Median age of patients with atrial fibrillation was 74 years, compared with 66 years in patients without atrial fibrillation (p = 0.0005. Patients with atrial fibrillation were more likely to have a history of atrial fibrillation (p = 0.03. 92% of the patients with atrial fibrillation suffered from DGE, compared to 46% of patients without atrial fibrillation (p = 0.0007. This association held true when controlling for age. CONCLUSION: Patients with postoperative atrial fibrillation are more likely to experience delayed gastric emptying. Interventions to manage delayed gastric function might be prudent in patients at high risk for postoperative atrial fibrillation.

  4. Late assembly of the Vibrio cholerae cell division machinery postpones septation to the last 10% of the cell cycle

    Science.gov (United States)

    Galli, Elisa; Paly, Evelyne; Barre, François-Xavier

    2017-01-01

    Bacterial cell division is a highly regulated process, which involves the formation of a complex apparatus, the divisome, by over a dozen proteins. In the few model bacteria in which the division process was detailed, divisome assembly occurs in two distinct steps: a few proteins, including the FtsZ tubulin-like protein, form a membrane associated contractile ring, the Z-ring, at ~30% of the cell cycle. The Z-ring serves as a scaffold for the recruitment of a second series of proteins, including integral membrane and periplasmic cell wall remodelling enzymes, at ~50% of the cell cycle. Actual septation occupies most of the remaining half of the cell cycle. In contrast, we present evidence suggesting that early pre-divisional Z-rings form between 40 and 50% of the cell cycle and mature into fully assembled divisome at about 80% of the cell cycle in Vibrio cholerae. Thus, actual septation is restricted to a very short amount of time. Our results further suggest that late assembly of the divisome probably helps maintain the asymmetric polar organisation of V. cholerae cells by limiting the accumulation of a cell pole marker, HubP, at the nascent cell poles. PMID:28300142

  5. The promoting role of an isolate of dark-septate fungus on its host plant Saussurea involucrata Kar. et Kir.

    Science.gov (United States)

    Wu, Li-qin; Lv, Ya-li; Meng, Zhi-xia; Chen, Juan; Guo, Shun-Xing

    2010-02-01

    A dark-septate endophytic (DSE) fungus EF-37 was isolated from the roots of Saussurea involucrata Kar. et Kir., an endangered Chinese medicinal plant. The molecular identification of the fungus was based on internal transcribed spacer regions and the result showed that EF-37 was congeneric to Mycocentrospora. This study was conducted to clarify the influence of the root endophyte EF-37 on the host plant S. involucrata using material grown in a sterile culture bottle. After cultivation for 40 days, fungal hyphae were found to be branching repeatedly and forming "hyphae nets" in the epidermal layers. Significant differences were detected between the study groups in plant dry weight, plant height, root dry weight, shoot dry weight, and the number of hair root tips. There was a positive effect of endophyte EF-37 on plant root development, with results showing that cortical cells dissolved and formed aerate structures. There was a positive effect of endophyte EF-37 on plant growth, but chlorophyll fluorescence analysis showed that there were no significant differences between the study groups. In addition, analysis of the chemical composition of seedlings showed that the level of rutin was higher in plants cultivated with the EF-37 fungus compared to the controls. This study helps to establish a basis for germplasm conservation and for further investigation of the interaction between dark-septate fungi and this alpine plant.

  6. Serum atrial natriuretic peptide (ANP) as an objective indicator for the diagnosis of neurogenic shock: animal experiment and human case report.

    Science.gov (United States)

    Zhao, Min-Zhu; Li, Yong-Guo; Zhang, Peng; Xiong, Jin-Cheng; Zhu, Shi-Sheng; Xiao, Xuan; Li, Jian-Bo

    2017-03-01

    In forensic medicine, the diagnosis of death due to neurogenic shock is considered to be an aporia, as lacking objective indicators and presenting atypical symptoms in autopsy. Medico-legal disputes and complaints occasionally result from this ambiguity. To explore potential objective indicators of neurogenic shock, we set up a model of neurogenic shock by applying an external mechanical force on the carotid sinus baroreceptor in rabbits. The serum atrial natriuretic peptide (ANP) level was measured by radioimmunoassay in the control group (n = 8), survival group (n = 15) and death group (n = 5) both before and after the insult. The serum ANP level showed a significant increase after the insult in the death group compared with the serum obtained before the insult (P = 0.006), while the serum ANP level after the insult in the survival group and control group was not statistically significant compared with the serum obtained before the insult (P = 0.332 and P = 0.492, respectively). To verify the repeatability of the model and the postmortem behavior of serum ANP, five healthy adult rabbits underwent the same procedure as the experimental group. The mortality rate was consistent with the former experiment (20 %). There were no significant changes in serum ANP level in vitro and in vivo (within 48 and 24 h, respectively). But there was a significant decrease in serum ANP level at 48 h postmortem in vivo (P = 0.001). A female patient who expired due to neurogenic shock during a hysteroscopy was reported. Neither fatal primary disease nor evidence for mechanical injuries or intoxication was found according to the autopsy. The serum ANP level was assayed as a supplementary indicator and was found to be three-fold higher than the normal maximum limit. Combined with the animal experiment, this case highlights that serum ANP has the potential to be an objective indicator for the diagnosis of death due to neurogenic shock.

  7. [New antithrombotics for atrial fibrillation].

    NARCIS (Netherlands)

    Verheugt, F.W.A.

    2011-01-01

    Cerebral infarction is the most serious complication of atrial fibrillation. Coumarin derivatives (vitamin K antagonists) counteract systemic thromboembolism and reduce the risk of stroke by more than 60%, but carry a risk of serious bleeding. Antiplatelet therapy and subcutaneous low-molecular-weig

  8. Radiofrequency ablation of atrial fibrillation

    NARCIS (Netherlands)

    Wiesfeld, ACP; Tan, ES; Van Veldhuisen, DJ; Crijns, HJGM; Van Gelder, IC

    2004-01-01

    Twenty-five patients (16 males, mean age 46 years.) underwent radiofrequency ablation because of either paroxysmal (13 patients) or persistent atrial fibrillation (12 patients). Ablation aimed at earliest activation of spontaneous and catheter-induced repetitive ectopy in left and right atria and ap

  9. Genetic basis of atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Oscar Campuzano

    2016-12-01

    Full Text Available Atrial fibrillation is the most common sustained arrhythmia and remains as one of main challenges in current clinical practice. The disease may be induced secondary to other diseases such as hypertension, valvular heart disease, and heart failure, conferring an increased risk of stroke and sudden death. Epidemiological studies have provided evidence that genetic factors play an important role and up to 30% of clinically diagnosed patients may have a family history of atrial fibrillation. To date, several rare variants have been identified in a wide range of genes associated with ionic channels, calcium handling protein, fibrosis, conduction and inflammation. Important advances in clinical, genetic and molecular basis have been performed over the last decade, improving diagnosis and treatment. However, the genetics of atrial fibrillation is complex and pathophysiological data remains still unraveling. A better understanding of the genetic basis will induce accurate risk stratification and personalized clinical treatment. In this review, we have focused on current genetics basis of atrial fibrillation.

  10. Facts about Atrial Septal Defect

    Science.gov (United States)

    ... Living With Heart Defects Data & Statistics Tracking & Research Articles & Key Findings Free Materials Multimedia and Tools Links to Other Websites Information For... Media Policy Makers Facts about Atrial Septal Defect Language: English Español (Spanish) Recommend on Facebook Tweet Share Compartir ...

  11. Personalized management of atrial fibrillation

    DEFF Research Database (Denmark)

    Kirchhof, Paulus; Breithardt, Günter; Aliot, Etienne

    2013-01-01

    The management of atrial fibrillation (AF) has seen marked changes in past years, with the introduction of new oral anticoagulants, new antiarrhythmic drugs, and the emergence of catheter ablation as a common intervention for rhythm control. Furthermore, new technologies enhance our ability to de...

  12. [Atrial fibrillation and cognitive function].

    Science.gov (United States)

    Duron, Emmanuelle; Hanon, Olivier

    2010-09-01

    Atrial fibrillation (AF), which prevalence increases with age, is a growing public health problem and a well known risk factor for stroke. On the other hand, dementia is one of the most important neurological disorders in the elderly, and with aging of the population in developed countries, the number of demented patients will increase in absence of prevention. In the past decade, several vascular risk factors (hypertension, obesity and metabolic syndrome, hypercholesterolemia) have been found, with various degree of evidence, to be associated with vascular dementia but also, surprisingly, with Alzheimer's disease. This review is devoted to the links between atrial fibrillation, cognitive decline and dementia. Globally, transversal studies showed a significant association between atrial fibrillation, cognitive decline and dementia. However, these studies are particularly sensitive to various biases. In this context, recent longitudinal studies of higher level of evidence have been conducted to assess the link between AF and dementia. One study disclosed a high incidence of dementia among patients suffering from atrial fibrillation during a 4.6 years follow-up. Similarly another study showed that atrial fibrillation was significantly associated with conversion from mild cognitive impairment to dementia during a 3 years follow-up. Nevertheless two other longitudinal studies did not find any significant association between AF and dementia, but this discrepancy should be interpreted taking into account that the comparability of all these studies is moderate because they were using different methodologies (population, cognitive testing, and mean follow-up). Possible explanatory mechanisms for the association between AF and the risk of dementia are proposed, such as thrombo-embolic ischemic damage and cerebral hypo perfusion due to fluctuations in the cardiac output. Thus, there is some evidence that FA could be associated with cognitive decline and dementia but this

  13. Advances in the research of dark septate endophytes%深色有隔内生真菌(DSE)研究进展

    Institute of Scientific and Technical Information of China (English)

    刘茂军; 张兴涛; 赵之伟

    2009-01-01

    @@ 深色有隔内生真菌(dark septate endophytes,DSE)不是一个科学的分类单元,而是泛指一群定殖于植物根内的小型土壤真菌,包括功能和分类关系都不确切的多种真菌.

  14. Atrioverter : An implantable device for the treatment of atrial fibrillation

    NARCIS (Netherlands)

    Wellens, HJJ; Lau, CP; Luderitz, B; Akhtar, M; Waldo, AL; Camm, AJ; Timmermans, C; Tse, HF; Jung, W; Jordaens, L; Ayers, G

    1998-01-01

    Background-During atrial fibrillation, electrophysiological changes occur in atrial tissue that favor the maintenance of the arrhythmia and facilitate recurrence after conversion to sinus rhythm. An implantable defibrillator connected to right atrial and coronary sinus defibrillation leads allows pr

  15. Left Atrial Tachycardia After Pulmonary Vein Isolation for Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Kenichi Hashimoto, MD

    2005-01-01

    Full Text Available Left atrial tachycardia (AT has been reported to occur after pulmonary vein isolation (PVI for the treatment of atrial fibrillation (AF. We treated 3 patients who developed AT of different mechanisms following PVI. In case 1, focal AT originating at the ostium of the left superior PV was demonstrated and focal radiofrequency ablation was performed at the breakthrough point at the ostium of the left superior PV terminated the AT. In case 2, AT was shown to be counterclockwise macroreentrant AT around the left inferior PV through the conduction gap of the left sided posterior wall for which linear ablation was performed between left superior and inferior PVs. Focal ablation at the conduction gap terminated the AT. In case 3, a macroreentrant AT propagating around the mitral annulus was demonstrated and linear ablation between left inferior pulmonary vein and mitral annulus (mitral isthmus terminated the AT.

  16. Atrial septal stenting - How I do it?

    Directory of Open Access Journals (Sweden)

    Kothandam Sivakumar

    2015-01-01

    Full Text Available A wide atrial communication is important to maintain hemodynamics in certain forms of congenital and acquired heart defects. In comparison to balloon septostomy or blade septostomy, atrial septal stenting provides a controlled, predictable, and long-lasting atrial communication. It often needs a prior Brockenbrough needle septal puncture to obtain a stable stent position. A stent deployed across a previously dilated and stretched oval foramen or tunnel form of oval foramen carries higher risk of embolization. This review provides technical tips to achieve a safe atrial septal stenting. Even though this is a "How to do it article," an initial discussion about the indications for atrial septal stenting is vital as the resultant size of the atrial septal communication should be tailored for each indication.

  17. Risk of atrial fibrillation in diabetes mellitus

    DEFF Research Database (Denmark)

    Pallisgaard, Jannik L.; Schjerning, Anne-Marie; Lindhardt, Tommi B.

    2016-01-01

    AIM: Diabetes has been associated with atrial fibrillation but the current evidence is conflicting. In particular knowledge regarding young diabetes patients and the risk of developing atrial fibrillation is sparse. The aim of our study was to investigate the risk of atrial fibrillation in patients...... with diabetes compared to the background population in Denmark. METHODS AND RESULTS: Through Danish nationwide registries we included persons above 18 years of age and without prior atrial fibrillation and/or diabetes from 1996 to 2012. The study cohort was divided into a background population without diabetes...... and a diabetes group. The absolute risk of developing atrial fibrillation was calculated and Poisson regression models adjusted for sex, age and comorbidities were used to calculate incidence rate ratios of atrial fibrillation. The total study cohort included 5,081,087 persons, 4,827,713 (95%) in the background...

  18. Atrial – Ventricular Septal Defect

    Directory of Open Access Journals (Sweden)

    T Panagiotopoulos

    2009-05-01

    Full Text Available Atrial and ventricular septal defect constitute the most common congenital heart disease.Aim: Τhe aim of the present retrospective study was to record data and factors that affect atrial and ventricular septal defect.Method and material: The sample study included patients of both sexes who were hospitalized with diagnosis atrial and ventricular septal defect in a Cardiac Surgery hospital of Athens. A specially constructed printed form was used for data collection, where were recorded the demographic and personal variables, the pathological, surgical, cardiology and obstetric history, the habits of adults, as well as the personal characteristics of mothers. Analysis of data was performed by descriptive statistical analysis.Results: The sample study consisted of 101 individuals with diagnosis atrial or ventricular Septal Defect, of which 40% were boys and 60% girls. The 70% of the sample study suffered from atrial Septal Defect and the 30% suffered from ventricular Septal Defect. Regarding age, 12% of the sample study was 0-1 years old, 35% was >1 years old, 8% was >12-18 years old and 45% over than 18 years old. Regarding educational status of the adult participants, 9% was of 0-6 years education, 22%>6 -12 years, 13%>12 years. 14% of the adult paticipants smoked, 4% consumed alcohol and 5% smoked in conjunction with alcohol. In terms of the obstetric history of the sample studied, 32% of the cases had normal birth, 4% had a twin birth and 1% had a triplet one. According to the variables related to mothers, the mean age of the mother was 30 years and 3 months, 10% were smokers at pregnancy and 3% used chemical substance and mainly hair color. Also, the results of the present study showed that individuals of 12-18 and >18 years old did not suffer from ventricular Septal Defect, whereas the infants 0-1 years old did not suffer from Atrial Septal Defect. The mean value of age at the admission in intensive care unit was 7 months (12% for the infants

  19. Impact of stepwise ablation on the biatrial substrate in patients with persistent atrial fibrillation and heart failure.

    Science.gov (United States)

    Jones, David G; Haldar, Shouvik K; Jarman, Julian W E; Johar, Sofian; Hussain, Wajid; Markides, Vias; Wong, Tom

    2013-08-01

    Ablation of persistent atrial fibrillation can be challenging, often involving not only pulmonary vein isolation (PVI) but also additional linear lesions and ablation of complex fractionated electrograms (CFE). We examined the impact of stepwise ablation on a human model of advanced atrial substrate of persistent atrial fibrillation in heart failure. In 30 patients with persistent atrial fibrillation and left ventricular ejection fraction ≤35%, high-density CFE maps were recorded biatrially at baseline, in the left atrium (LA) after PVI and linear lesions (roof and mitral isthmus), and biatrially after LA CFE ablation. Surface area of CFE (mean cycle length ≤120 ms) remote to PVI and linear lesions, defined as CFE area, was reduced after PVI (18.3±12.03 to 10.2±7.1 cm(2); PCFE reduction (P=0.02). Right atrial CFE area was reduced by LA ablation, from 25.9±14.1 to 12.9±11.8 cm(2) (PCFE area was progressively reduced following PVI and linear lesions, and LA ablation reduced right atrial CFE area. Reduction of CFE area at sites remote from ablation would suggest either regression of the advanced atrial substrate or that these CFE were functional phenomena. Nevertheless, in an advanced atrial fibrillation substrate, linear lesions after PVI diminished the target area for CFE ablation, and complete lesions resulted in a favorable clinical outcome.

  20. ANALYSIS OF RANDOMNESS OF ATRIAL AND VENTRICULAR RHYTHM IN ATRIAL-FIBRILLATION

    NARCIS (Netherlands)

    VANDENBERG, MP; DELANGEN, CDJ; HAAKSMA, J; BEL, KJ; CRIJNS, HJGM; DIJK, WA; LIE, KI

    1995-01-01

    The aim of the present study was top examine the relationship between randomness of atrial and ventricular rhythm during atrial fibrillation. Atrial fibrillation was induced in 10 open-chest pigs by application of metacholine on the surface of the right atrium followed by incremental pacing. Local a

  1. Correlation of Left Atrial Diameter by Echocardiography and Left Atrial Volume by Computed Tomography

    NARCIS (Netherlands)

    Hof, Irene; Arbab-Zadeh, Armin; Scherr, Daniel; Chilukuri, Karuna; Dalal, Darshan; Abraham, Theodore; Lima, Joao; Calkins, Hugh

    2009-01-01

    Computed Tomography. Introduction: For patients undergoing catheter ablation of atrial fibrillation (AF), left atrial size is a predictor of recurrence of AF during follow-up. For this reason, major clinical trials have used a left atrial diameter (LAD) of more than 5.0 or 5.5 cm, assessed by echoca

  2. The effects of rhythm control strategies versus rate control strategies for atrial fibrillation and atrial flutter

    DEFF Research Database (Denmark)

    Sethi, Naqash; Safi, Sanam; Nielsen, Emil E

    2017-01-01

    BACKGROUND: Atrial fibrillation is the most common arrhythmia of the heart with a prevalence of approximately 2% in the western world. Atrial flutter, another arrhythmia, occurs less often with an incidence of approximately 200,000 new patients per year in the USA. Patients with atrial fibrillation...... as healthcare systems and healthcare economy. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42016051433....

  3. Congenital left atrial appendage aneurysm: Atypical presentation

    Directory of Open Access Journals (Sweden)

    Mehdi Bamous

    2017-01-01

    Full Text Available Congenital left atrial appendage aneurysm is a rare condition caused by dysplasia of the atrial muscles. We report a case of a 14-year-old boy, with a 5-month history of cough and in sinus rhythm. Transthoracic echocardiography and computerized tomographic angiography confirmed the aneurysm of the left atrial appendage which was resected through median sternotomy on cardiopulmonary bypass. This case is presented not only for its rarity but also for its atypical clinical presentation.

  4. Interaction between a Dark Septate Endophytic Isolate from Dendrobium sp.and Roots of D.nobile Seedlings

    Institute of Scientific and Technical Information of China (English)

    Xiao-Qiang Hou; Shun-Xing Guo

    2009-01-01

    Interactions between an isolate of dark septate endophytas (DSE) and roots of Dendroblum nobile Lindl.seedlings are reported in this paper.The isolate was obtained from orchid mycorrhizas on Dendrobium sp.in subtropical forest.The fungus formed typical orchid mycorrhiza in aseptic co-culture with D.nobile seedlings on modified Murashige-Skoog (MMS)medium.Anatomic observations of the infected roots showed that the DSE hyphae invaded the velamen layer,passed through passage cells in exodermis,entered the cortex cells,and then formed fungal pelotons of orchid mycorrhiza.D.nobile seedlings' plant height,stem diameter,new roots number and biomass were greatly enhanced by inoculating the fungus to seedlings.The fungus was identified as Leptodontidium by sequencing the polymerase chain reaction-amplified rDNA ITSt-5.8S-ITS2 (internal transcribed spacer (ITS)) regions and comparison with similar taxa.

  5. An Extended, Boolean Model of the Septation Initiation Network in S.Pombe Provides Insights into Its Regulation.

    Science.gov (United States)

    Chasapi, Anastasia; Wachowicz, Paulina; Niknejad, Anne; Collin, Philippe; Krapp, Andrea; Cano, Elena; Simanis, Viesturs; Xenarios, Ioannis

    2015-01-01

    Cytokinesis in fission yeast is controlled by the Septation Initiation Network (SIN), a protein kinase signaling network using the spindle pole body as scaffold. In order to describe the qualitative behavior of the system and predict unknown mutant behaviors we decided to adopt a Boolean modeling approach. In this paper, we report the construction of an extended, Boolean model of the SIN, comprising most SIN components and regulators as individual, experimentally testable nodes. The model uses CDK activity levels as control nodes for the simulation of SIN related events in different stages of the cell cycle. The model was optimized using single knock-out experiments of known phenotypic effect as a training set, and was able to correctly predict a double knock-out test set. Moreover, the model has made in silico predictions that have been validated in vivo, providing new insights into the regulation and hierarchical organization of the SIN.

  6. Arbuscular mycorrhizal morphology and dark septate fungal associations in medicinal and aromatic plants of Western Ghats, Southern India.

    Science.gov (United States)

    Muthukumar, T; Senthilkumar, M; Rajangam, M; Udaiyan, K

    2006-12-01

    We investigated roots of 107 medicinal and aromatic plants (MAPs) in the Western Ghats region of Southern India for arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) associations. Of the 107 MAPs belonging to 98 genera in 52 families examined, 79 were AM and 38 harbored a DSE association. Typical Arum- and Paris-type mycorrhizas are first reported in the presumed nonmycorrhizal family Amaranthaceae. Similarly, DSE associations are recorded for the first time in nine plant families and 37 plant species. Thirty MAPs had both AM and DSE associations. The number of MAPs having Arum-type mycorrhiza was greater than those having Paris-type. This was more prominent among herbaceous plants than in trees where the Paris-type was predominant. Similarly, the Arum-type was more prevalent in annuals than in perennials. DSE associations were more frequent in herbs and perennials compared to other MAPs.

  7. Mycorrhizal and dark septate endophytic fungi under the canopies of desert plants in Mu Us Sandy Land of China

    Institute of Scientific and Technical Information of China (English)

    Yanqing WU; Tiantian LIU; Xueli HE

    2009-01-01

    Biodiversity of arbuscular mycorrhizal colonization and spore density was investigated in 20 desert plants (dominant or common species) collected from different locations of Mu Us Sandy Land of China. We observed three mycorrhizal types including Arum-type, Paris-type, and an intermediate type among the plants. Another type of potentially beneficial fungi associated with roots of all species was also observed, namely, dark septate endophytic fungi (DSEF). Of the 20 sample plants examined, all species were coinfected by the two target fungi (Arbuscular mycorrhizal fungi (AMF) colonization of Salixpsammophila and DSEF colonization of Periploca septum were as low as 4%). Based on this investigation, we speculated that the DSEF are ubiquitous in desert ecosystems and can co-occur with AMF in desert plants, functioning much like mycorrhizal fungi. Further studies will be required to elucidate interactional mechanisms with AMF and the mechanisms operating in desert ecosystem.

  8. The role of a dark septate endophytic fungus, Veronaeopsis simplex Y34, in Fusarium disease suppression in Chinese cabbage.

    Science.gov (United States)

    Khastini, Rida O; Ohta, Hiroyuki; Narisawa, Kazuhiko

    2012-08-01

    The soil-inhabiting fungal pathogen Fusarium oxysporum has been an increasing threat to Chinese cabbage (Brassica campestris L.). A dark septate endophytic fungus, Veronaeopsis simplex Y34, isolated from Yaku Island, Japan, was evaluated in vitro for the ability to suppress Fusarium disease. Seedlings grown in the presence of the endophyte showed a 71% reduction in Fusarium wilt disease and still had good growth. The disease control was achieved through a synergetic effect involving a mechanical resistance created by a dense network of V. simplex Y34 hyphae, which colonized the host root, and siderophore production acting indirectly to induce a resistance mechanism in the plant. Changes in the relative abundance of the fungal communities in the soil as determined by fluorescently labelled T-RFs (terminal restriction fragments), appeared 3 weeks after application of the fungus. Results showed the dominance of V. simplex Y34, which became established in the rhizosphere and out-competed F. oxysporum.

  9. Occurrence of Arbuscular Mycorrhizas and Dark Septate Endophytes in Hydrophytes from Lakes and Streams in Southwest China

    Science.gov (United States)

    Kai, Wang; Zhiwei, Zhao

    2006-02-01

    In this study, the colonization of arbuscular mycorrhizas (AM) and dark septate endophytes (DSE) in 140 specimens of 32 hydrophytes collected from four lakes and four streams in southwest China were investigated. The arbuscular mycorrhizal fungi (AMF) and DSE colonization in these hydrophytes were rare. Typical AM structures were observed in one of the 25 hydrophytic species collected in lakes and six of the 17 species collected in streams.Spores of 10 identified AMF species and an unidentified Acaulospora sp. were isolated from the sediments. The identified AMF came from the four genera, Acaulospora, Gigaspora, Glomus and Scutellospora . Glomus and G. mosseae were the dominant genus and species respectively in these aquatic environments.The presence of DSE in hydrophytes was recorded for the first time. DSE occurred in one of the 25 hydrophyte species collected in lakes and three of the 17 species collected in streams.

  10. Structural Molecular Components of Septate Junctions in Cnidarians Point to the Origin of Epithelial Junctions in Eukaryotes

    KAUST Repository

    Ganot, P.

    2014-09-21

    Septate junctions (SJs) insure barrier properties and control paracellular diffusion of solutes across epithelia in invertebrates. However, the origin and evolution of their molecular constituents in Metazoa have not been firmly established. Here, we investigated the genomes of early branching metazoan representatives to reconstruct the phylogeny of the molecular components of SJs. Although Claudins and SJ cytoplasmic adaptor components appeared successively throughout metazoan evolution, the structural components of SJs arose at the time of Placozoa/Cnidaria/Bilateria radiation. We also show that in the scleractinian coral Stylophora pistillata, the structural SJ component Neurexin IV colocalizes with the cortical actin network at the apical border of the cells, at the place of SJs. We propose a model for SJ components in Cnidaria. Moreover, our study reveals an unanticipated diversity of SJ structural component variants in cnidarians. This diversity correlates with gene-specific expression in calcifying and noncalcifying tissues, suggesting specific paracellular pathways across the cell layers of these diploblastic animals.

  11. Atrial fibrillation in the elderly

    Institute of Scientific and Technical Information of China (English)

    Roger Kerzner; Michael W. Rich

    2005-01-01

    Atrial fibrillation (AF) is an extremely common condition in the elderly, with increasing prevalence around the world as the population ages. AF may be associated with serious health consequences, including stroke, heart failure, and decreased quality of life, so that careful management of AF by geriatric health care providers is required. With careful attention to anticoagulation therapy, and prudent use of medications and invasive procedures to minimize symptoms, many of the adverse health consequences of AF can be prevented.

  12. CORRELATION OF LEFT ATRIAL SIZE AND ATRIAL FIBRILLATION IN RHD WITH MITRAL VALVE DISEASE

    Directory of Open Access Journals (Sweden)

    Raghavendra

    2016-03-01

    Full Text Available BACKGROUND Atrial fibrillation (AF, the most common sustained cardiac rhythm disturbance, commonly occurs with rheumatic heart disease, particularly mitral stenosis. Hemodynamic impairment and thromboembolic events result in significant morbidity& mortality. Left atrial (LA enlargement is one of the elements that evolve in the natural history of mitral stenosis. The objective of this study is to study the relation between echo cardio graphically determined left atrial size and atrial fibrillation in mitral valve disease (MVD. METHODOLOGY 50 Patients with rheumatic heart disease with mitral valve disease were studied using ECG and ECHO, excluding patients with congenital heart diseases, non-rheumatic mitral valve disease, essential hypertension, patients undergone PTMC or valvuloplasty or valve replacement, coronary artery diseases, patients on antiarrhythmic drugs, pregnant women. Left atrial dimensions measured by ECHO in patients of MVD and AF on ECG were compared with the left atrial dimension of patients in sinus rhythm. RESULTS In this study 42 patients had left atrial size >40 mm, 29(93.55% of them were in atrial fibrillation and only 13(68.42% were in sinus rhythm. Among 8 patients with left atrial size <40 mm, 2(6.45% were in atrial fibrillation and 06(31.58% were in sinus rhythm with p<0.02 which is significant. CONCLUSION Atrial fibrillation incidence was common when left atrial dimension was above 40 mm. There is a quantitative relation between left atrial size measured echocardiographically and the presence or absence of atrial fibrillation. These results may have therapeutic implication in that it may be possible with echocardiography, to identify patients in sinus rhythm, who are at high risk of developing atrial fibrillation. Prophylactic anticoagulation, antiarrhythmic therapy or both might be considered in management to prevent embolism.

  13. Optimisation of Ionic Models to Fit Tissue Action Potentials: Application to 3D Atrial Modelling

    Directory of Open Access Journals (Sweden)

    Amr Al Abed

    2013-01-01

    Full Text Available A 3D model of atrial electrical activity has been developed with spatially heterogeneous electrophysiological properties. The atrial geometry, reconstructed from the male Visible Human dataset, included gross anatomical features such as the central and peripheral sinoatrial node (SAN, intra-atrial connections, pulmonary veins, inferior and superior vena cava, and the coronary sinus. Membrane potentials of myocytes from spontaneously active or electrically paced in vitro rabbit cardiac tissue preparations were recorded using intracellular glass microelectrodes. Action potentials of central and peripheral SAN, right and left atrial, and pulmonary vein myocytes were each fitted using a generic ionic model having three phenomenological ionic current components: one time-dependent inward, one time-dependent outward, and one leakage current. To bridge the gap between the single-cell ionic models and the gross electrical behaviour of the 3D whole-atrial model, a simplified 2D tissue disc with heterogeneous regions was optimised to arrive at parameters for each cell type under electrotonic load. Parameters were then incorporated into the 3D atrial model, which as a result exhibited a spontaneously active SAN able to rhythmically excite the atria. The tissue-based optimisation of ionic models and the modelling process outlined are generic and applicable to image-based computer reconstruction and simulation of excitable tissue.

  14. A rare case of human mycosis by Rhizoctonia solani.

    Science.gov (United States)

    Kaore, N M; Atul, A R; Khan, M Z; Ramnani, V K

    2012-01-01

    Rhizoctonia solani is a most widely recognized strong saprophyte with a great diversity of host plants. It is a first ever case of extensive human mycosis caused by Rhizoctonia solani in a 65-year-old diabetic and hypertensive farmer, with a history of head injury caused by fall of mud wall. Necrotic material collected revealed septate fungal hyphae with bacterial co-infection. Fungal culture on SDA at 25°C showed cotton wooly growth progressing to greyish-white to shiny metallic black colonies and identified on basis of septate mycelial growth without conidia, right angle branching, presence of compact hyphal forms and anastomosis between branching hyphae on LPCB mount.

  15. PAROXYSMAL ATRIAL FIBRILLATION: CHOICE OF CARDIOVERSION THERAPY

    Directory of Open Access Journals (Sweden)

    B. A. Tatarskii

    2007-01-01

    Full Text Available Characteristics and classification of different patterns of paroxysmal atrial fibrillation are presented. Main indications to restoration of sinus rhythm are discussed. The features of main medications used to terminate of atrial fibrillation are given. The choice of antiarrhythmic drug is considerate. Necessity of individual approach to therapy tactics is proved.

  16. A novel and simple atrial retractor.

    Science.gov (United States)

    Kofidis, Theo; Lee, Chuen Neng

    2011-05-01

    Minimally invasive cardiac operations require specialized equipment. Atrial retractors are a frequently used tool to expose heart valves for minimally invasive and open procedures. The models currently available in the market are efficient; however, they may be complex, bulky, or expensive. We introduce a novel, very simple atrial retractor we designed using ubiquitously available materials.

  17. Atrial Arrhythmia Summit: Post Summit Report

    Science.gov (United States)

    Barr, Yael

    2010-01-01

    The Atrial Arrhythmia Summit brought together nationally and internationally recognized experts in cardiology, electrophysiology, exercise physiology, and space medicine in an effort to elucidate the mechanisms, risk factors, and management of atrial arrhythmias in the unique occupational cohort of the U.S. astronaut corps.

  18. Corticosteroids and the risk of atrial fibrillation

    NARCIS (Netherlands)

    van der Hooft, CS; Heeringa, J; Brusselle, GG; Hofman, A; Witteman, JCM; Kingma, JH; Sturkenboom, MCJM; Stricker, BHC

    2006-01-01

    Background: High-dose ( pulse) corticosteroid therapy has been associated with the development of atrial fibrillation. This association, however, is mainly based on case reports. Methods: To test the hypothesis that high-dose corticosteroid exposure increases the risk of new-onset atrial fibrillatio

  19. Atrial fibrillation in rats induced by rapid transesophageal atrial pacing during brief episodes of asphyxia: A new in vivo model

    DEFF Research Database (Denmark)

    Haugan, K.; Lam, Henrik Rye; Knudsen, C. B.;

    2004-01-01

    Non-pharmacological in vivo models of atrial fibrillation (AF) have been developed in large animals only. We aimed to develop and characterize a new small animal non-pharmacological in vivo model of AF. AF was induced by transesophageal atrial burst pacing during 35 seconds periods of asphyxia...... was associated with a marked profibrillatory effect. Increasing gap junction intracellular communication using the antiarrhythmic peptide analogue AAP 10 did not affect AF duration. Basal plasma level of epinephrine and norepinephrine were increased 5- to 20-fold relative to values reported by others......, but unchanged following 35 seconds of asphyxia. The results from our study demonstrate that the rat model shares several clinical key characteristics with human AF: (1) hemodynamic response to AF; (2) increased autonomic tone; (3) antiarrhythmic effects of clinically used drugs; (4) profibrillatory effect...

  20. Atrial Remodeling And Atrial Fibrillation: Mechanistic Interactions And Clinical Implications

    OpenAIRE

    2009-01-01

    Atrial fibrillation (AF) is the most common arrhythmia in clinical practice. The prevalence of AF increases dramatically with age and is seen in as high as 9% of individuals by the age of 80 years. In high-risk patients, the thromboembolic stroke risk can be as high as 9% per year and is associated with a 2-fold increase in mortality. Although the pathophysiological mechanism underlying the genesis of AF has been the focus of many studies, it remains only partially understood. Conventional th...

  1. Atrial fibrillation in patients with ischemic stroke

    DEFF Research Database (Denmark)

    Thygesen, Sandra Kruchov; Frost, Lars; Eagle, Kim A;

    2009-01-01

    BACKGROUND: Atrial fibrillation is a major risk factor for ischemic stroke. However, the prognostic impact of atrial fibrillation among patients with stroke is not fully clarified. We compared patient characteristics, including severity of stroke and comorbidity, quality of in-hospital care...... and outcomes in a cohort of first-time ischemic stroke patients with and without atrial fibrillation. METHODS: Based on linkage of public medical databases, we did a population-based follow-up study among 3,849 stroke patients from the County of Aarhus, Denmark admitted in the period of 2003......-2007 and prospectively registered in the Danish National Indicator Project. RESULTS: Atrial fibrillation was associated with an adverse prognostic profile but not with an overall poorer quality of in-hospital care. Patients with atrial fibrillation had a longer total length of stay (median: 15 vs 9 days), and were...

  2. 风湿性心房颤动患者左心房组织中钙蛋白酶-2的表达%Expression of calpain-2 in human left atrium in rheumatic atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    韩波; 王建春; 张涛; 朱小龙; 李丛; 王正军; 赵勇; 邹承伟

    2014-01-01

    目的:观察风湿性心房颤动(AF)患者左心房中钙蛋白酶-2(calpain-2)的表达,探讨其在AF发病机制中的作用。方法选取外科换瓣手术的风湿性心脏病患者39例,分为窦性心律组( n=16例)和心房颤动组( n=23例)。应用RT-PCR技术和免疫组化LSAB法半定量检测calpain-2的表达。结果心房颤动组calpain-2 mRNA的deltaCt值高于窦性心律组[(0.091±0.035) vs (0.066±0.022),P=0.017];两组左心房心肌细胞中均有棕黄色颗粒沉着,心外膜和心内膜细胞均未见棕黄色颗粒;心房颤动组中calpain-2表达含量明显高于窦性心律组( P<0.001),两者平均光密度值分别为0.92±0.17和0.65±0.01;calpain-2的含量与左心房收缩末期直径呈正相关(r=0.929, P<0.001)。结论 calpain-2在人类左心房心肌细胞中表达;AF时calpain-2的表达明显增加。%Objective To observe the expression of calpain-2 in the left atrum of patients with rheumatic atrial fibrilla-tion, and to explore its roles in the pathogenesis of atrial fibrillation.Methods A total of 39 patients with rheumatic heart disease who received surgical valve replacement were divided into two groups: the atrial fibrillation group ( n=23) and sinus rhythm group (n=16).The expression of calpain-2 was detected with LSAB immunohistochemical and the Real-time PCR technology.Results The deltaCt of calpain-2 mRNA of the atrial fibrillation group ( 0.091 ± 0.035) was higher than that of the sinus rhythm group (0.066 ±0.022, P=0.017).Brown particle deposits were ob-served in the left atrial myocytes in both groups, but the epicardial and endocardial cells showed no brown particles.The average optical density values of calpain-2 of the atrial fibrillation group and sinus rhythm group were (0.92 ±0.17) and (0.65 ±0.01)(P<0.001).Calpain-2 levels and left atrial systolic diameter were correlated (r=0.929, P<0.01).Conclusion

  3. Artificial atrial fibrillation in the dog. An artifact?

    NARCIS (Netherlands)

    Strackee, J.; Hoelen, A.J.; Zimmerman, A.N.E.; Meijler, F.L.

    1971-01-01

    R-R interval sequences during artificial atrial fibrillation in dogs were studied in the same way as in patients in a previous study and compared with results obtained in dogs with spontaneous atrial fibrillation. Artificial atrial fibrillation was effected by right atrial stimulation in three close

  4. Galectin-3 in patients undergoing ablation of atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Nicolas Clementy

    2014-11-01

    Conclusions: Persistent type of atrial fibrillation is an independent predictor of higher Galectin-3 concentration. This biomarker of fibrosis may be implied in the mechanisms of atrial remodeling and maintenance of atrial fibrillation, and thus be helpful for the design of therapeutic strategy in patients with atrial fibrillation.

  5. Paleomycology of the Princeton Chert II. Dark-septate fungi in the aquatic angiosperm Eorhiza arnoldii indicate a diverse assemblage of root-colonizing fungi during the Eocene.

    Science.gov (United States)

    Klymiuk, Ashley A; Taylor, Thomas N; Taylor, Edith L; Krings, Michael

    2013-01-01

    Tissues of the extinct aquatic or emergent angiosperm, Eorhiza arnoldii incertae sedis, were extensively colonized by microfungi, and in this study we report the presence of several types of sterile mycelia. In addition to inter- and intracellular proliferation of regular septate hyphae, the tissues contain monilioid hyphae with intercalary branching. These filamentous mycelia are spatially associated with two distinct morphotypes of intracellular microsclerotia. These quiescent structures are morphologically similar to loose and cerebriform microsclerotia found within the living tissues of some plants, which have been attributed to an informal assemblage of dematiaceous ascomycetes, the dark-septate endophytes. While there are significant challenges to interpreting the ecology of fossilized fungi, these specimens provide evidence for asymptomatic endophytic colonization of the rooting structures of a 48.7 million year old aquatic angiosperm.

  6. Surgical Treatment of Concomitant Atrial Fibrillation: Focus onto Atrial Contractility

    Directory of Open Access Journals (Sweden)

    Claudia Loardi

    2015-01-01

    Full Text Available Background. Maze procedure aims at restoring sinus rhythm (SR and atrial contractility (AC. This study evaluated multiple aspects of AC recovery and their relationship with SR regain after ablation. Methods. 122 mitral and fibrillating patients underwent radiofrequency Maze. Rhythm check and echocardiographic control of biatrial contractility were performed at 3, 6, 12, and 24 months postoperatively. A multivariate Cox analysis of risk factors for absence of AC recuperation was applied. Results. At 2-years follow-up, SR was achieved in 79% of patients. SR-AC coexistence increased from 76% until 98%, while biatrial contraction detection augmented from 84 to 98% at late stage. Shorter preoperative arrhythmia duration was the only common predictor of SR-AC restoring, while pulmonary artery pressure (PAP negatively influenced AC recuperation. Early AC restoration favored future freedom from arrhythmia recurrence. Minor LA dimensions correlated with improved future A/E value and vice versa. Right atrial (RA contractility restoring favored better left ventricular (LV performance and volumes. Conclusions. SR and left AC are two interrelated Maze objectives. Factors associated with arrhythmia “chronic state” (PAP and arrhythmia duration are negative predictors of procedural success. Our results suggest an association between postoperative LA dimensions and “kick” restoring and an influence of RA contraction onto LV function.

  7. Left atrial ball valve thrombus

    Directory of Open Access Journals (Sweden)

    R. Balaji

    2013-10-01

    Full Text Available "Ball valve thrombus" which is a spherical free floating clot in left atrium is an often quoted, but uncommonly encountered complication in patients with severe mitral stenosis of rheumatic origin, who are in atrial fibrillation. We describe the case of a 31-year-old lady with rheumatic heart disease, severe mitral stenosis and moderately severe aortic stenosis who had undergone closed mitral valvotomy 13 years ago. The patient presented with an episode of non-exertional syncope and breathlessness on exertion of 6 months duration and was in normal sinus rhythm. Echocardiography facilitated ante-mortem diagnosis and prompt institution of surgery was life saving.

  8. Atrial and ventricular volume and function in persistent and permanent atrial fibrillation, a magnetic resonance imaging study

    DEFF Research Database (Denmark)

    Therkelsen, Susette Krohn; Groenning, Bjoern Aaris; Svendsen, Jesper Hastrup

    2005-01-01

    Left atrial size is independently related to cardiovascular morbidity and mortality, and atrial fibrillation (AF) is strongly associated with atrial size. Our aims were to report atrial and ventricular dimensions in patients with AF evaluated with magnetic resonance imaging (MRI), and to assess t...

  9. Mapping strategy for multiple atrial tachyarrhythmias in a transplant heart

    DEFF Research Database (Denmark)

    Jin, Qi; Pehrson, Steen; Jacobsen, Peter Karl;

    2015-01-01

    BACKGROUND: Different atrial arrhythmias can coexist in the recipient and donor atria after heart transplantation. CASE PRESENTATION: We report an unusual case of a patient with three different types of atrial arrhythmia after heart transplantation: an atrial fibrillation in the recipient atria....... CONCLUSIONS: It is critical to understand the surgical anatomy of a bi-atrial anastomosis and its relevant electrical activation pattern before ablation. Appropriate electroanatomical mapping strategy with RMN can facilitate the successful ablation of post-transplant atrial arrhythmias....

  10. Age-related changes in dispersion of atrial effective refractory period and its ionic mechanism in canines

    Institute of Scientific and Technical Information of China (English)

    SUN Qi; TANG Min; LI Ning; PU Jie-lin; ZHANG Shu

    2007-01-01

    @@ Atrial fibrillation (AF) is the most common cardiac arrhythmia in man, and epidemiological study has shown the close relationship between the incidence of AF and aging.1 Although the effects of aging on atrial electrophysiology have been investigated in humans and animal models,2-9 the electrophysiological changes that make the atria of aged individuals more susceptible to AF than those of adults remain poorly understood.

  11. Atrial fibrillation and survival in colorectal cancer

    Directory of Open Access Journals (Sweden)

    Justin Timothy A

    2004-11-01

    Full Text Available Abstract Background Survival in colorectal cancer may correlate with the degree of systemic inflammatory response to the tumour. Atrial fibrillation may be regarded as an inflammatory complication. We aimed to determine if atrial fibrillation is a prognostic factor in colorectal cancer. Patients and methods A prospective colorectal cancer patient database was cross-referenced with the hospital clinical-coding database to identify patients who had underwent colorectal cancer surgery and were in atrial fibrillation pre- or postoperatively. Results A total of 175 patients underwent surgery for colorectal cancer over a two-year period. Of these, 13 patients had atrial fibrillation pre- or postoperatively. Atrial fibrillation correlated with worse two-year survival (p = 0.04; log-rank test. However, in a Cox regression analysis, atrial fibrillation was not significantly associated with survival. Conclusion The presence or development of atrial fibrillation in patients undergoing surgery for colorectal cancer is associated with worse overall survival, however it was not found to be an independent factor in multivariate analysis.

  12. Anticoagulation therapy for atrial fibrillation.

    Science.gov (United States)

    Hylek, Elaine M

    2013-03-01

    Atrial fibrillation (AF) is the most common significant cardiac rhythm disorder, and its prevalence is increasing worldwide. Atrial fibrillation confers a fivefold increased risk of stroke, and these strokes are associated with significant mortality and disability. The vitamin K antagonist, warfarin, has been the mainstay of anticoagulant therapy for patients with AF, reducing the risk of stroke by 65%. Despite its efficacy, warfarin remains underused in clinical practice because of its variable dose response, diet and medication interactions, and need for frequent monitoring. Stroke prevention in AF has entered an exciting therapeutic era with new classes of targeted anticoagulants that avoid the many pitfalls of the vitamin K antagonists. Dabigatran, an oral thrombin inhibitor, and the factor Xa inhibitors, rivaroxaban and apixaban, have demonstrated efficacy for stroke prevention and a reduced risk of intracranial hemorrhage relative to warfarin. Translating the efficacy of clinical trials into effective use of these novel agents in clinical practice will require an understanding of their pharmacokinetic profiles, dose selection, and management in select clinical situations.

  13. Incidence and clinical predictors of subsequent atrial fibrillation requiring additional ablation after cavotricuspid isthmus ablation for typical atrial flutter.

    Science.gov (United States)

    De Bortoli, Alessandro; Shi, Li-Bin; Ohm, Ole-Jørgen; Hoff, Per Ivar; Schuster, Peter; Solheim, Eivind; Chen, Jian

    2017-06-01

    We sought to investigate the incidence of atrial fibrillation after catheter ablation for typical atrial flutter and to determine the predictors for symptomatic atrial fibrillation that required a further additional dedicated ablation procedure. 127 patients underwent elective cavotricuspid isthmus ablation with the indication of symptomatic, typical atrial flutter. The occurrence of atrial flutter, atrial fibrillation, cerebrovascular events and the need for additional ablation procedures for symptomatic atrial fibrillation was assessed during long-term follow-up. The majority of patients (70%) manifested atrial fibrillation during a follow-up period of 68 ± 24 months, and a significant proportion (42%) underwent one or multiple atrial fibrillation ablation procedures after an average of 26 months from the index procedure. Recurrence of typical atrial flutter was rare. Ten patients (8%) suffered cerebrovascular events. Earlier documentation of atrial fibrillation (OR 3.53), previous use of flecainide (OR 3.33) and left atrial diameter (OR 2.96) independently predicted occurrence of atrial fibrillation during the follow-up. A combination of pre- and intra-procedural documentation of atrial fibrillation (OR 3.81) and previous use of flecainide (OR 2.43) independently predicted additional atrial fibrillation ablation. Atrial fibrillation occurred in the majority of patients after ablation for typical atrial flutter and 42% of them required an additional dedicated ablation procedure. Pre- and intraprocedural documentation of atrial fibrillation together with previous use of flecainide independently predicted atrial fibrillation occurrence and a need for additional ablation. Anticoagulation treatment should be continued in high-risk patients in spite of clinical disappearance of atrial flutter.

  14. Impact of pulmonary vein isolation on atrial vagal activity and atrial electrical remodeling

    Institute of Scientific and Technical Information of China (English)

    Yingxue Dong; Shulong Zhang; Lianjun Gao; Hongwei Zhao; Donghui Yang; Yunlong Xia; Yanzong Yang

    2008-01-01

    Objective Mechanisms of pulmonary vein isolation (PVI) for atrial fibrillation remain controversy.This study aimed to investigate the impact of PVI on vagal modulation to atria.Methods Eighteen adult mongrel dogs under general anesthesia were randomly divided into two groups.Bilateral cervical sympathovagal trunks were decentralized and sympathetic effects was blocked by metoprolol administration.Atrial electrical remodeling (AER) was established by rapid right atrial pacing at the rate of 600 bpm for 30 minutes.PVI was performed in group A.Atrial effective refractory period (ERP),vulnerability window (VW) of atrial fibrillation,and sinus rhythm cycle length (SCL) were measured at baseline and during vagal stimulation before and after atrial rapid pacing with and without PVI at fight atrial appendage (RAA),left atrial appendage (LAA),distal coronary sinus (CSd) and proximal coronary sinus (CSp).Results (1) Effects of PVI on vagal modulation:Shortening of SCL during vagal stimulation decreased significantly after PVI compared with that before PVI in group A (P<0.001).Shortening of ERP during vagal stimulation decreaseed significantly after PVI compared with that before PVI (P<0.05).VW of atrial fibrillation during vagal stimulation decreased significantly after PVI compared with that before PVI (P<0.05).(2) Effects of PVI on AER:shortening of ERP before and after atrial rapid pacing increased significantly at baseline and vagal stimulation in group B compared with that in group A (P<0.05).VW during vagal stimulation increased significantly after atrial rapid pacing in group B (P<0.05).Conclusion PVI attenuates the vagal modulation to the atria,thereby decreases the susceptibility to atrial fibrillation mediated by vagal activity.PVI releases AER,which maybe contributes to the vagal denervation.Our study indicates that PVI not only can eradicate triggered foci but also modify substrates for AF.(J Geriatr Cardiol 2008;5:28-32)

  15. Response of atrial flutter to overdrive atrial pacing and intravenous disopyramide phosphate, singly and in combination.

    Science.gov (United States)

    Camm, J; Ward, D; Spurrell, R

    1980-01-01

    Ten patients who suffered spontaneous paroxysms of atrial flutter were investigated by electrophysiological techniques. Two had overt Wolff-Parkinson-White syndrome; three Lown-Ganong-Levine syndrome; and one a concealed accessory atrioventricular connection. Atrial flutter was initiated, at study, by right atrial pacing and electrograms from the right atrium and coronary sinus were observed for at least five minutes to ensure stable flutter in both atria. Atrial flutter was terminated by 2.5 s or 5 s bursts of atrial pacing at rates 10, 50, or 100 beats/min faster than the intrinsic flutter rate in only two patients. Atrial flutter, which was reinitiated in two patients, was then treated with intravenous disopyramide phosphate, 2 mg/kg body weight, infused over five minutes. In all 10 patients the atrial rate slowed from a mean of 310 +/- 39 beats/min to 217 +/- 27 beats/min and atrial flutter terminated in one case. Though the mean ventricular rate fell from 161 +/- 52 beats/min to 156 +/- 45 beats/min the atrioventricular conduction ratio fell from 2.17 +/- 0.86 to 1.55 +/- 0.59 and four patients were left with symptomatically significant increases of ventricular rate. In seven of nine patients overdrive atrial pacing, repeated after disopryamide, resulted in the conversion of atrial flutter to sinus rhythm. In this study, overdrive atrial pacing and intravenous disopyramide, singly and in combination, terminated atrial flutter in nine of the 10 patients and it is suggested that this method may provide an effective alternative to direct current cardioversion. PMID:7426181

  16. The circadian variation of premature atrial contractions

    DEFF Research Database (Denmark)

    Larsen, Bjørn Strøier; Kumarathurai, Preman; Nielsen, Olav W

    2016-01-01

    AIMS: The aim of the study was to assess a possible circadian variation of premature atrial contractions (PACs) in a community-based population and to determine if the daily variation could be used to assess a more vulnerable period of PACs in predicting later incidence of atrial fibrillation (AF...... variation in heart rate. After adjusting for relevant risk factors, the risk of AF was equal in all time intervals throughout the day. CONCLUSION: Premature atrial contractions showed a circadian variation in subjects with frequent PACs. No specific time interval of the day was more predictive of AF than...

  17. Evidence for biotrophic lifestyle and biocontrol potential of dark septate endophyte Harpophora oryzae to rice blast disease.

    Directory of Open Access Journals (Sweden)

    Zhen-Zhu Su

    Full Text Available The mutualism pattern of the dark septate endophyte (DSE Harpophora oryzae in rice roots and its biocontrol potential in rice blast disease caused by Magnaporthe oryzae were investigated. Fluorescent protein-expressing H. oryzae was used to monitor the colonization pattern. Hyphae invaded from the epidermis to the inner cortex, but not into the root stele. Fungal colonization increased with root tissue maturation, showing no colonization in the meristematic zone, slight colonization in the elongation zone, and heavy colonization in the differentiation zone. H. oryzae adopted a biotrophic lifestyle in roots accompanied by programmed cell death. Real-time PCR facilitated the accurate quantification of fungal growth and the respective plant response. The biocontrol potential of H. oryzae was visualized by inoculation with eGFP-tagged M. oryzae in rice. H. oryzae protected rice from M. oryzae root invasion by the accumulation of H2O2 and elevated antioxidative capacity. H. oryzae also induced systemic resistance against rice blast. This systemic resistance was mediated by the OsWRKY45-dependent salicylic acid (SA signaling pathway, as indicated by the strongly upregulated expression of OsWRKY45. The colonization pattern of H. oryzae was consistent with the typical characteristics of DSEs. H. oryzae enhanced local resistance by reactive oxygen species (ROS and high antioxidative level and induced OsWRKY45-dependent SA-mediated systemic resistance against rice blast.

  18. Unraveling the role of dark septate endophyte (DSE) colonizing maize (Zea mays) under cadmium stress: physiological, cytological and genic aspects.

    Science.gov (United States)

    Wang, Jun-ling; Li, Tao; Liu, Gao-yuan; Smith, Joshua M; Zhao, Zhi-wei

    2016-02-25

    A growing body of evidence suggests that plant root-associated fungi such as dark septate endophytes (DSE) can help plants overcome many biotic and abiotic stresses, of great interest is DSE-plant metal tolerance and alleviation capabilities on contaminated soils. However, the tolerance and alleviation mechanisms involved have not yet been elucidated. In the current study, the regulation and physiological response of Zea mays to its root-associated DSE, Exophiala pisciphila was analyzed under increased soil Cd stress (0, 10, 50, 100 mg kg(-1)). Under Cd stress, DSE inoculation significantly enhanced the activities of antioxidant enzymes and low-molecular weight antioxidants, while also inducing increased Cd accumulation in the cell wall and conversion of Cd into inactive forms by shoot and root specific regulation of genes related to metal uptake, translocation and chelation. Our results showed that DSE colonization resulted in a marked tolerance to Cd, with a significant decrease in cadmium phytotoxicity and a significant increase in maize growth by triggering antioxidant systems, altering metal chemical forms into inactive Cd, and repartitioning subcellular Cd into the cell wall. These results provide comprehensive evidence for the mechanisms by which DSE colonization bioaugments Cd tolerance in maize at physiological, cytological and molecular levels.

  19. Improved tolerance of maize (Zea mays L.) to heavy metals by colonization of a dark septate endophyte (DSE) Exophiala pisciphila

    Energy Technology Data Exchange (ETDEWEB)

    Li, T.; Liu, M.J.; Zhang, X.T. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Zhang, H.B. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Department of Biology, Yunnan University, Kunming, 650091 Yunnan (China); Sha, T. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Zhao, Z.W., E-mail: zhaozhw@ynu.edu.cn [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China)

    2011-02-15

    Dark septate endophytes (DSE) are ubiquitous and abundant in stressful environments including heavy metal (HM) stress. However, our knowledge about the roles of DSE in improving HM tolerance of their host plants is poor. In this study, maize (Zea mays L.) was inoculated with a HM tolerant DSE strain Exophiala pisciphila H93 in lead (Pb), zinc (Zn), and cadmium (Cd) contaminated soils. E. pisciphila H93 successfully colonized and formed typical DSE structures in the inoculated maize roots. Colonization of E. pisciphila H93 alleviated the deleterious effects of excessive HM supplements and promoted the growth of maize (roots and shoots) under HM stress conditions, though it significantly decreased the biomass of inoculated maize under no HM stress. Further analysis showed that the colonization of E. pisciphila H93 improved the tolerance of maize to HM by restricting the translocation of HM ions from roots to shoots. This study demonstrated that under higher HM stress, such a mutual symbiosis between E. pisciphila and its host (maize) may be an efficient strategy to survive in the stressful environments. - Research Highlights: {yields}Effect of DSE (E. pisciphila) on heavy metal tolerance of maize host was studied. {yields}DSE alleviated the deleterious effect of excessive heavy metals on maize. {yields}DSE restricted the transfer of heavy metals from the roots to shoots in maize. {yields}DSE colonization improved the tolerance of their host plants to heavy metals.

  20. Mitigation of antagonistic effects on plant growth due to root co-colonization by dark septate endophytes and ectomycorrhiza.

    Science.gov (United States)

    Reininger, Vanessa; Sieber, Thomas N

    2013-12-01

    Dark septate endophytes (DSE) are very common root colonizers of woody plant species. Ascomycetes of the Phialocephala fortinii s.l.-Acephala applanata species complex (PAC) are the main representatives of DSE fungi in forest ecosystems. PAC and mycorrhizal fungi share the same habitat, but interactions among PAC, mycorrhizal fungi and plants are poorly understood. We compared the effects of single and dual inoculation of Norway spruce seedlings with PAC and the ectomycorrhizal (ECM) fungus Hebeloma crustuliniforme on host growth, degree of mycorrhization and density of endophytic PAC biomass. Single colonization by H. crustuliniforme or PAC significantly reduced plant biomass. Dual colonization reduced or neutralized plant growth depression caused by single fungal colonization. The degree of mycorrhization was independent on PAC colonization, and mycorrhization significantly reduced endophytic PAC biomass. Plant biomass of dually colonized plants positively correlated with PAC biomass. These results demonstrate the ability of dual inoculation of PAC and H. crustuliniforme to neutralize plant growth depression caused by single fungal inoculation. Our explanations of enhanced plant growth in dually inoculated plants are the inhibition of PAC during root colonization by the ECM mantle and ECM-mediated access to plant growth-promoting nutrients resulting from the mineralization of the potting medium by PAC.

  1. Sex-specific interaction between arbuscular mycorrhizal and dark septate fungi in the dioecious plant Antennaria dioica (Asteraceae).

    Science.gov (United States)

    Vega-Frutis, R; Varga, S; Kytöviita, M-M

    2013-05-01

    Male and female plants of dioecious species often differ in their resource demands and this has been linked to secondary sexual dimorphism, including sex-specific interactions with other organisms such as herbivores and pollinators. However, little is known about the interaction between dioecious plants and fungal root endophytes. Plants may be simultaneously colonised by arbuscular mycorrhizal (AM) and dark septate (DS) fungi. While it is well established that AM mutualism involves reciprocal transfer of photosynthates and mineral nutrients between roots of host plants and these fungi, the role of DS fungi remains controversial. Here, we report the temporal and spatial variation in AM and DS fungi in female, male and non-reproductive Antennaria dioica plants in three natural populations in Finland during flowering and after seed production. Females had higher colonisation by AM fungi, but lower colonisation by DS fungi than male and non-reproductive plants. The higher AM colonisation was observed during flowering, and this difference varied among populations. Our results suggest that females and males of A. dioica interact with AM and DS fungi differently and that this relationship is dependent on soil fertility.

  2. Plant growth promotion, metabolite production and metal tolerance of dark septate endophytes isolated from metal-polluted poplar phytomanagement sites.

    Science.gov (United States)

    Berthelot, Charlotte; Leyval, Corinne; Foulon, Julie; Chalot, Michel; Blaudez, Damien

    2016-10-01

    Numerous studies address the distribution and the diversity of dark septate endophytes (DSEs) in the literature, but little is known about their ecological role and their effect on host plants, especially in metal-polluted soils. Seven DSE strains belonging to Cadophora, Leptodontidium, Phialophora and Phialocephala were isolated from roots of poplar trees from metal-polluted sites. All strains developed on a wide range of carbohydrates, including cell-wall-related compounds. The strains evenly colonized birch, eucalyptus and ryegrass roots in re-synthesis experiments. Root and shoot growth promotion was observed and was both plant and strain dependent. Two Phialophora and Leptodontidium strains particularly improved plant growth. However, there was no correlation between the level of root colonization by DSEs and the intensity of growth promotion. All strains produced auxin and six also stimulated plant growth through the release of volatile organic compounds (VOCs). SPME-GC/MS analyses revealed four major VOCs emitted by Cadophora and Leptodontidium The strains exhibited growth at high concentrations of several metals. The ability of metal-resistant DSE strains to produce both soluble and volatile compounds for plant growth promotion indicates interesting microbial resources with high potential to support sustainable production of bioenergy crops within the context of the phytomanagement of metal-contaminated sites.

  3. Evidence for biotrophic lifestyle and biocontrol potential of dark septate endophyte Harpophora oryzae to rice blast disease.

    Science.gov (United States)

    Su, Zhen-Zhu; Mao, Li-Juan; Li, Na; Feng, Xiao-Xiao; Yuan, Zhi-Lin; Wang, Li-Wei; Lin, Fu-Cheng; Zhang, Chu-Long

    2013-01-01

    The mutualism pattern of the dark septate endophyte (DSE) Harpophora oryzae in rice roots and its biocontrol potential in rice blast disease caused by Magnaporthe oryzae were investigated. Fluorescent protein-expressing H. oryzae was used to monitor the colonization pattern. Hyphae invaded from the epidermis to the inner cortex, but not into the root stele. Fungal colonization increased with root tissue maturation, showing no colonization in the meristematic zone, slight colonization in the elongation zone, and heavy colonization in the differentiation zone. H. oryzae adopted a biotrophic lifestyle in roots accompanied by programmed cell death. Real-time PCR facilitated the accurate quantification of fungal growth and the respective plant response. The biocontrol potential of H. oryzae was visualized by inoculation with eGFP-tagged M. oryzae in rice. H. oryzae protected rice from M. oryzae root invasion by the accumulation of H2O2 and elevated antioxidative capacity. H. oryzae also induced systemic resistance against rice blast. This systemic resistance was mediated by the OsWRKY45-dependent salicylic acid (SA) signaling pathway, as indicated by the strongly upregulated expression of OsWRKY45. The colonization pattern of H. oryzae was consistent with the typical characteristics of DSEs. H. oryzae enhanced local resistance by reactive oxygen species (ROS) and high antioxidative level and induced OsWRKY45-dependent SA-mediated systemic resistance against rice blast.

  4. A shift from arbuscular mycorrhizal to dark septate endophytic colonization in Deschampsia flexuosa roots occurs along primary successional gradient.

    Science.gov (United States)

    Huusko, K; Ruotsalainen, A L; Markkola, A M

    2017-02-01

    Soil fungal community and dominant mycorrhizal types are known to shift along with plant community changes during primary succession. However, it is not well understood how and why root fungal symbionts and colonization types vary within the plant host when the host species is able to thrive both at young and at old successional stages with different light and nutrient resource availability. We asked (i) how root fungal colonization of Deschampsia flexuosa (Poaceae) by arbuscular mycorrhizal (AM) fungi and dark septate endophytes (DSE) changes along a postglacial primary successional land uplift gradient. As neighboring vegetation may play a role in root fungal colonization, we also asked (ii) whether removal of the dominant neighbor, Empetrum nigrum ssp. hermaphroditum (Ericaceae), affects root fungal colonization of Deschampsia. We also studied whether (iii) foliar carbon (C) and nitrogen (N) concentration of Deschampsia is related to successional changes along a land uplift gradient. AM colonization decreased (-50 %), DSE colonization increased (+200 %), and foliar C declined in Deschampsia along with increasing successional age, whereas foliar N was not affected. Empetrum removal did not affect AM colonization but increased DSE sclerotial colonization especially at older successional stages. The observed decrease in foliar C coincides with an increase in canopy closure along with increasing successional age. We suggest that the shift from an AM-dominated to a DSE-dominated root fungal community in Deschampsia along a land uplift successional gradient may be related to different nutritional benefits gained through these root fungal groups.

  5. Improved tolerance of maize (Zea mays L.) to heavy metals by colonization of a dark septate endophyte (DSE) Exophiala pisciphila.

    Science.gov (United States)

    Li, T; Liu, M J; Zhang, X T; Zhang, H B; Sha, T; Zhao, Z W

    2011-02-15

    Dark septate endophytes (DSE) are ubiquitous and abundant in stressful environments including heavy metal (HM) stress. However, our knowledge about the roles of DSE in improving HM tolerance of their host plants is poor. In this study, maize (Zea mays L.) was inoculated with a HM tolerant DSE strain Exophiala pisciphila H93 in lead (Pb), zinc (Zn), and cadmium (Cd) contaminated soils. E. pisciphila H93 successfully colonized and formed typical DSE structures in the inoculated maize roots. Colonization of E. pisciphila H93 alleviated the deleterious effects of excessive HM supplements and promoted the growth of maize (roots and shoots) under HM stress conditions, though it significantly decreased the biomass of inoculated maize under no HM stress. Further analysis showed that the colonization of E. pisciphila H93 improved the tolerance of maize to HM by restricting the translocation of HM ions from roots to shoots. This study demonstrated that under higher HM stress, such a mutual symbiosis between E. pisciphila and its host (maize) may be an efficient strategy to survive in the stressful environments.

  6. Functional and transcript analysis of a novel metal transporter gene EpNramp from a dark septate endophyte (Exophiala pisciphila).

    Science.gov (United States)

    Wei, Yun-Fang; Li, Tao; Li, Ling-Fei; Wang, Jun-Ling; Cao, Guan-Hua; Zhao, Zhi-Wei

    2016-02-01

    Various metal transporters mediate sub-cellular sequestration of diverse metal ions, contribute to cellular metal tolerance, and control metal partitioning, particularly under conditions of high rates of metal influx into organisms. In the current study, a ubiquitous and evolutionary conserved metal transporter gene, homology to natural resistance associated macrophage protein (Nramp), was cloned from a metal-tolerant isolate of dark septate endophyte (DSE, Exophiala pisciphila), and its functional and transcript characterization were analyzed. The full-length Nramp gene from E. pisciphila (named EpNramp) was 1716 bp and expected to encode a polypeptide of 571 amino acid residues. EpNramp fused to green fluorescent protein suggested that EpNramp was a plasma membrane metal transporter, which was consistent with the results of bioinformatics analysis with 11 transmembrane domains. Yeast functional complementation revealed that EpNramp could complement the growth defect of Fe-uptake yeast mutant (fet3fet4 double mutant) by mediating the transport of Fe(2+). Expression of EpNramp increased Cd(2+) sensitivity and Cd(2+) accumulation in yeast. In addition, qPCR data revealed that E. pisciphila significantly down-regulated EpNramp expression with elevated Cd(2+) exposure. Altogether, EpNramp is a bivalent cation transporter localized in cell membrane, which is necessary for efficient translocation of both Fe and Cd, and its activities partly attributed to the tolerance of DSE to toxic and excessive Cd(2+) supplements.

  7. Septation of infectious hyphae is critical for appressoria formation and virulence in the smut fungus Ustilago maydis.

    Directory of Open Access Journals (Sweden)

    Johannes Freitag

    2011-05-01

    Full Text Available Differentiation of hyphae into specialized infection structures, known as appressoria, is a common feature of plant pathogenic fungi that penetrate the plant cuticle. Appressorium formation in U. maydis is triggered by environmental signals but the molecular mechanism of this hyphal differentiation is largely unknown. Infectious hyphae grow on the leaf surface by inserting regularly spaced retraction septa at the distal end of the tip cell leaving empty sections of collapsed hyphae behind. Here we show that formation of retraction septa is critical for appressorium formation and virulence in U. maydis. We demonstrate that the diaphanous-related formin Drf1 is necessary for actomyosin ring formation during septation of infectious hyphae. Drf1 acts as an effector of a Cdc42 GTPase signaling module, which also consists of the Cdc42-specific guanine nucleotide exchange factor Don1 and the Ste20-like kinase Don3. Deletion of drf1, don1 or don3 abolished formation of retraction septa resulting in reduced virulence. Appressorium formation in these mutants was not completely blocked but infection structures were found only at the tip of short filaments indicating that retraction septa are necessary for appressorium formation in extended infectious hyphae. In addition, appressoria of drf1 mutants penetrated the plant tissue less frequently.

  8. Mycorrhizal and Dark-Septate Fungi in Plant Roots above 4270 Meters Elevation in the Andes and Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Steven K. [University of Colorado; Sobieniak-Wiseman, L. Cheyanne [University of Colorado; Kageyama, Stacy A. [Oregon State University; Halloy, Stephen [Instituto de Ecologia, Universidad Mayor de San Andres, La Paz, Bolivia; Schadt, Christopher Warren [ORNL

    2008-01-01

    Arbuscular mycorrhizal (AM) and dark-septate endophytic (DSE) fungi were quantified in plant roots from high-elevation sites in the Cordillera Vilcanota of the Andes (Per ) and the Front Range of the Colorado Rocky Mountains (U.S.A.). At the highest sites in the Andes (5391 m) AM fungi were absent in the two species of plants sampled (both Compositae) but roots of both were heavily colonized by DSE fungi. At slightly lower elevations (5240 5250 m) AM fungi were present in roots while DSE fungi were rare in plants outside of the composite family. At the highest sites sampled in Colorado (4300 m) AM fungi were present, but at very low levels and all plants sampled contained DSE fungi. Hyphae of coarse AM fungi decreased significantly in plant roots at higher altitude in Colorado, but no other structures showed significant decreases with altitude. These new findings indicate that the altitudinal distribution of mycorrhizal fungi observed for European mountains do not necessarily apply to higher and drier mountains that cover much of the Earth (e.g. the Himalaya, Hindu Kush, Andes, and Rockies) where plant growth is more limited by nutrients and water than in European mountains. This paper describes the highest altitudinal records for both AM and DSE fungi, surpassing previous reported altitudinal maxima by about 1500 meters.

  9. Delivery of double singleton pregnancies in a woman with a double uterus, double cervix, and complete septate vagina

    Directory of Open Access Journals (Sweden)

    Ming-Jie Yang

    2015-12-01

    Full Text Available Uterine anomalies involving a double uterus, double cervix, also known as didelphys uterus, and complete septate vagina are rarely seen and have an associated fertility problem. However, artificial reproductive technology with embryo transfers can help solve this fertility challenge. Conception in the uterus in just one side is commonly seen for embryos, which are always transferred through the usually used (dilated vagina. We here present a patient with the above uterine anomaly who conceived with the aid of in vitro fertilization and embryo transfer to both uterine cavities under general anesthesia, which resulted in successful double singleton pregnancies with one fetus in each uterus. With intensive prenatal care, the pregnancy course for each fetus was rather uneventful. Although both fetuses were in cephalic presentation, cesarean section was performed at the 39th week of gestation with good outcomes in order to preclude anticipated difficulties if the baby had been delivered through the rarely dilated vagina. However, order of birth between the two fetuses was a crucial decision during the operation.

  10. Unraveling the role of dark septate endophyte (DSE) colonizing maize (Zea mays) under cadmium stress: physiological, cytological and genic aspects

    Science.gov (United States)

    Wang, Jun-ling; Li, Tao; Liu, Gao-yuan; Smith, Joshua M.; Zhao, Zhi-wei

    2016-01-01

    A growing body of evidence suggests that plant root-associated fungi such as dark septate endophytes (DSE) can help plants overcome many biotic and abiotic stresses, of great interest is DSE-plant metal tolerance and alleviation capabilities on contaminated soils. However, the tolerance and alleviation mechanisms involved have not yet been elucidated. In the current study, the regulation and physiological response of Zea mays to its root-associated DSE, Exophiala pisciphila was analyzed under increased soil Cd stress (0, 10, 50, 100 mg kg−1). Under Cd stress, DSE inoculation significantly enhanced the activities of antioxidant enzymes and low-molecular weight antioxidants, while also inducing increased Cd accumulation in the cell wall and conversion of Cd into inactive forms by shoot and root specific regulation of genes related to metal uptake, translocation and chelation. Our results showed that DSE colonization resulted in a marked tolerance to Cd, with a significant decrease in cadmium phytotoxicity and a significant increase in maize growth by triggering antioxidant systems, altering metal chemical forms into inactive Cd, and repartitioning subcellular Cd into the cell wall. These results provide comprehensive evidence for the mechanisms by which DSE colonization bioaugments Cd tolerance in maize at physiological, cytological and molecular levels. PMID:26911444

  11. Unraveling the role of dark septate endophyte (DSE) colonizing maize (Zea mays) under cadmium stress: physiological, cytological and genic aspects

    Science.gov (United States)

    Wang, Jun-Ling; Li, Tao; Liu, Gao-Yuan; Smith, Joshua M.; Zhao, Zhi-Wei

    2016-02-01

    A growing body of evidence suggests that plant root-associated fungi such as dark septate endophytes (DSE) can help plants overcome many biotic and abiotic stresses, of great interest is DSE-plant metal tolerance and alleviation capabilities on contaminated soils. However, the tolerance and alleviation mechanisms involved have not yet been elucidated. In the current study, the regulation and physiological response of Zea mays to its root-associated DSE, Exophiala pisciphila was analyzed under increased soil Cd stress (0, 10, 50, 100 mg kg-1). Under Cd stress, DSE inoculation significantly enhanced the activities of antioxidant enzymes and low-molecular weight antioxidants, while also inducing increased Cd accumulation in the cell wall and conversion of Cd into inactive forms by shoot and root specific regulation of genes related to metal uptake, translocation and chelation. Our results showed that DSE colonization resulted in a marked tolerance to Cd, with a significant decrease in cadmium phytotoxicity and a significant increase in maize growth by triggering antioxidant systems, altering metal chemical forms into inactive Cd, and repartitioning subcellular Cd into the cell wall. These results provide comprehensive evidence for the mechanisms by which DSE colonization bioaugments Cd tolerance in maize at physiological, cytological and molecular levels.

  12. Dynamic approximate entropy electroanatomic maps detect rotors in a simulated atrial fibrillation model.

    Science.gov (United States)

    Ugarte, Juan P; Orozco-Duque, Andrés; Tobón, Catalina; Kremen, Vaclav; Novak, Daniel; Saiz, Javier; Oesterlein, Tobias; Schmitt, Clauss; Luik, Armin; Bustamante, John

    2014-01-01

    There is evidence that rotors could be drivers that maintain atrial fibrillation. Complex fractionated atrial electrograms have been located in rotor tip areas. However, the concept of electrogram fractionation, defined using time intervals, is still controversial as a tool for locating target sites for ablation. We hypothesize that the fractionation phenomenon is better described using non-linear dynamic measures, such as approximate entropy, and that this tool could be used for locating the rotor tip. The aim of this work has been to determine the relationship between approximate entropy and fractionated electrograms, and to develop a new tool for rotor mapping based on fractionation levels. Two episodes of chronic atrial fibrillation were simulated in a 3D human atrial model, in which rotors were observed. Dynamic approximate entropy maps were calculated using unipolar electrogram signals generated over the whole surface of the 3D atrial model. In addition, we optimized the approximate entropy calculation using two real multi-center databases of fractionated electrogram signals, labeled in 4 levels of fractionation. We found that the values of approximate entropy and the levels of fractionation are positively correlated. This allows the dynamic approximate entropy maps to localize the tips from stable and meandering rotors. Furthermore, we assessed the optimized approximate entropy using bipolar electrograms generated over a vicinity enclosing a rotor, achieving rotor detection. Our results suggest that high approximate entropy values are able to detect a high level of fractionation and to locate rotor tips in simulated atrial fibrillation episodes. We suggest that dynamic approximate entropy maps could become a tool for atrial fibrillation rotor mapping.

  13. Navx-guided Cryoablation of Atrial Tachycardia Inside the Left Atrial Appendage

    Science.gov (United States)

    Pandozi, Claudio; Galeazzi, Marco; Lavalle, Carlo; Ficili, Sabina; Russo, Maurizio; Santini, Massimo

    2010-01-01

    Radiofrequency ablation procedures inside the left atrial appendage (LAA) are likely to involve dangerous complications because of a high thrombogenic effect. Cryoablation procedures are supposed to be safer. We describe two cases of successful cryoablation procedures. Two NavX-guided cryoablations of permanent focal atrial arrhythmias arising from the LAA were performed. Left atrial reconstruction and mapping allowed the zone of the earliest atrial potential to be recorded; the entire course of the ablation catheter was monitored. The arrhythmias were successfully ablated; no thrombotic complications were observed. PMID:21346824

  14. Increasing Prevalence of Atrial Fibrillation and Permanent Atrial Arrhythmias in Congenital Heart Disease.

    Science.gov (United States)

    Labombarda, Fabien; Hamilton, Robert; Shohoudi, Azadeh; Aboulhosn, Jamil; Broberg, Craig S; Chaix, Marie A; Cohen, Scott; Cook, Stephen; Dore, Annie; Fernandes, Susan M; Fournier, Anne; Kay, Joseph; Macle, Laurent; Mondésert, Blandine; Mongeon, François-Pierre; Opotowsky, Alexander R; Proietti, Anna; Rivard, Lena; Ting, Jennifer; Thibault, Bernard; Zaidi, Ali; Khairy, Paul

    2017-08-15

    Atrial arrhythmias are the most common complication encountered in the growing and aging population with congenital heart disease. This study sought to assess the types and patterns of atrial arrhythmias, associated factors, and age-related trends. A multicenter cohort study enrolled 482 patients with congenital heart disease and atrial arrhythmias, age 32.0 ± 18.0 years, 45.2% female, from 12 North American centers. Qualifying arrhythmias were classified by a blinded adjudicating committee. The most common presenting arrhythmia was intra-atrial re-entrant tachycardia (IART) (61.6%), followed by atrial fibrillation (28.8%), and focal atrial tachycardia (9.5%). The proportion of arrhythmias due to IART increased with congenital heart disease complexity from 47.2% to 62.1% to 67.0% in patients with simple, moderate, and complex defects, respectively (p = 0.0013). Atrial fibrillation increased with age to surpass IART as the most common arrhythmia in those ≥50 years of age (51.2% vs. 44.2%; p heart disease, with a predominantly paroxysmal pattern. However, atrial fibrillation increases in prevalence and atrial arrhythmias progressively become permanent as the population ages. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  15. Towards Low Energy Atrial Defibrillation

    Directory of Open Access Journals (Sweden)

    Philip Walsh

    2015-09-01

    Full Text Available A wireless powered implantable atrial defibrillator consisting of a battery driven hand-held radio frequency (RF power transmitter (ex vivo and a passive (battery free implantable power receiver (in vivo that enables measurement of the intracardiac impedance (ICI during internal atrial defibrillation is reported. The architecture is designed to operate in two modes: Cardiac sense mode (power-up, measure the impedance of the cardiac substrate and communicate data to the ex vivo power transmitter and cardiac shock mode (delivery of a synchronised very low tilt rectilinear electrical shock waveform. An initial prototype was implemented and tested. In low-power (sense mode, >5 W was delivered across a 2.5 cm air-skin gap to facilitate measurement of the impedance of the cardiac substrate. In high-power (shock mode, >180 W (delivered as a 12 ms monophasic very-low-tilt-rectilinear (M-VLTR or as a 12 ms biphasic very-low-tilt-rectilinear (B-VLTR chronosymmetric (6ms/6ms amplitude asymmetric (negative phase at 50% magnitude shock was reliably and repeatedly delivered across the same interface; with >47% DC-to-DC (direct current to direct current power transfer efficiency at a switching frequency of 185 kHz achieved. In an initial trial of the RF architecture developed, 30 patients with AF were randomised to therapy with an RF generated M-VLTR or B-VLTR shock using a step-up voltage protocol (50–300 V. Mean energy for successful cardioversion was 8.51 J ± 3.16 J. Subsequent analysis revealed that all patients who cardioverted exhibited a significant decrease in ICI between the first and third shocks (5.00 Ω (SD(σ = 1.62 Ω, p < 0.01 while spectral analysis across frequency also revealed a significant variation in the impedance-amplitude-spectrum-area (IAMSA within the same patient group (|∆(IAMSAS1-IAMSAS3[1 Hz − 20 kHz] = 20.82 Ω-Hz (SD(σ = 10.77 Ω-Hz, p < 0.01; both trends being absent in all patients that failed to cardiovert

  16. Atrial Fibrillation During an Exploration Class Mission

    Science.gov (United States)

    Lipsett, Mark; Hamilton, Douglas; Lemery, Jay; Polk, James

    2011-01-01

    This slide presentation reviews a possible scenario of an astronaut having Atrial Fibrillation during a Mars Mission. In the case review the presentation asks several questions about the alternatives for treatment, medications and the ramifications of the decisions.

  17. POSTOPERATIVE ATRIAL FIBRILLATION – AN UPDATE

    Directory of Open Access Journals (Sweden)

    Johnson Francis

    2015-12-01

    Full Text Available Atrial fibrillation is the most common perioperative cardiac arrhythmia. Sympathetic overactivity, inflammatory state and oxidative stress are important contributors to the genesis of postoperative atrial fibrillation. Advancing age and mitral valve disease along with left atrial size are important parameters in noted in multivariate prediction model. Genetic predisposition has also been noted. Preventive strategies tried include beta blockers, statins, posterior pericardiotomy, carperitide infusion and thoracic epidural analgesia. Treatment options include rate and rhythm control along with anticoagulation if it persists more than 48 hours with high CHADS2 score. Some of the therapeutic modalities which have been found to be NOT useful in preventing post operative atrial fibrillation are dexamethasone, magnesium infusion and concomitant pulmonary vein isolation.

  18. Atrial Fibrillation and Stroke in Elderly Patients

    Directory of Open Access Journals (Sweden)

    Geetanjali Dang

    2016-11-01

    Full Text Available The increasing prevalence of stroke, with an estimated annual cost of $71.5 billion, has made it a major health problem that increases disability and death, particularly in patients with atrial fibrillation. Although advanced age and atrial fibrillation are recognized as strong risk factors for stroke, the basis for this susceptibility are not well defined. Aging or associated diseases are accompanied by changes in rheostatic, humoral, metabolic and hemodynamic factors that may contribute more to stroke predisposition than rhythm abnormality alone. Several thromboembolism-predisposing clinical characteristics and serum biomarkers with prognostic significance have been identified in patients with atrial fibrillation. Although anticoagulation decreases the risk of thromboembolism, management in the elderly remains complex due to major concerns about bleeding. New anticoagulants and nonpharmacologic strategies are helpful to reduce the risk of bleeding, particularly in older-elderly patients. Herein, we review the pathogenesis and management of select issues of thromboembolism in the elderly with atrial fibrillation.

  19. [Cardiac rehabilitation in patients with atrial fibrillation].

    Science.gov (United States)

    Schlitt, Axel; Kamke, Wolfram; Guha, Manju; Haberecht, Olaf; Völler, Heinz

    2015-06-01

    The course of cardiac rehabilitation is often altered due to episodes of paroxysmal, predominantly postoperative atrial fibrillation. In symptomatic patients, a TEE-guided cardioversion - preferential DC shock - is indicated. In patients with persistent / permanent atrial fibrillation, a heart rate up to 110 / min and 170 / min at rest and during physical activity should, respectively, be tolerated. Therefore, training should not be quitted by heart rate but rather by load. The antithrombotic management is in addition a great task in treating patients with atrial fibrillation. With the exception of patients with a CHA2DS2-VASc-Score < 1, oral anticoagulation is indicated. Atrial fibrillation has little impact on social aspects, whereas the underlying heart disease and drug treatment (oral anticoagulation) has an important impact.

  20. Alcohol consumption and risk of atrial fibrillation

    DEFF Research Database (Denmark)

    Tolstrup, Janne Schurmann; Wium-Andersen, Marie Kim; Ørsted, David Dynnes

    2016-01-01

    BACKGROUND: The aim of this study was to test the hypothesis that alcohol consumption, both observational (self-reported) and estimated by genetic instruments, is associated with a risk of atrial fibrillation and to determine whether people with high cardiovascular risk are more sensitive towards...... register. As a measure of alcohol exposure, both self-reported consumption and genetic variations in alcohol metabolizing genes (ADH1B/ADH1C) were used as instrumental variables. The endpoint was admission to hospital for atrial fibrillation as recorded in a validated hospital register. RESULTS: A total...... of 3493 cases of atrial fibrillation occurred during follow-up. High alcohol consumption was associated with a risk of atrial fibrillation among men, but not among women. Among the men who drank 28-35 and 35+ drinks/week, the hazards ratios were 1.40 (95% confidence interval 1.09-1.80) and 1.62 (95...

  1. Atrial conduction delay predicts atrial fibrillation in paroxysmal supraventricular tachycardia patients after radiofrequency catheter ablation.

    Science.gov (United States)

    Xu, Zhen-Xing; Zhong, Jing-Quan; Zhang, Wei; Yue, Xin; Rong, Bing; Zhu, Qing; Zheng, Zhaotong; Zhang, Yun

    2014-06-01

    This study aimed to assess whether intra- and inter-atrial conduction delay could predict atrial fibrillation (AF) for paroxysmal supraventricular tachycardia (PSVT) patients after successful treatment by radiofrequency catheter ablation (RFCA). Echocardiography examination was performed on 524 consecutive PSVT patients (15 patients were excluded). Left atrial dimension, right atrial diameter and intra- and inter-atrial conduction delay were measured before ablation. Patients were divided into group A (n = 32): occurrence of AF after the ablation and group B (n = 477): remained in sinus rhythm during follow-up. Receiver operating characteristic (ROC) curve analysis was performed to estimate the predictive value of intra- and inter-atrial conduction delay. Both intra- and inter-atrial conduction delay were higher in group A than in group B (4.79 ± 0.30 msec vs. 4.56 ± 0.32 msec; 21.98 ± 1.32 msec vs. 20.01 ± 1.33; p < 0.05). Binary logistic regression analysis showed that intra- and inter-atrial conduction were significant influential factors for the occurrence of AF (odds ratio [OR] = 13.577, 95% confidence interval [CI], 3.469-48.914; OR = 2.569, 95% CI, 1.909-3.459, p < 0.05). The ROC cure analysis revealed that intra-atrial conduction delay ≥ 4.45 msec and inter-atrial conduction delay ≥ 20.65 were the most optimal cut-off value for predicting AF in PSVT patients after RFCA. In conclusion, this is the first study to show that the intra- and inter-atrial conduction delay could effectively predict AF in post-ablation PSVT patients.

  2. Calpain I Inhibition prevents atrial structural remodeling in a canine model with atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    XUE Hong-jie; SHAN Hong-bo; LIU Jie; LI Wei-min; LI Yue; GONG Yong-tai; YANG Bao-feng; JIN Cheng-luo; SHENG Li; CHU Shan; ZHANG Li

    2008-01-01

    Background Atrial fibrillation (AF) is accompanied by atrial structural remodeling. Calpain activity is induced during AR To lest a causal relationship between calpain activation and atrial structural changes, N-acetyl-Leu-Leu-Met (ALLM), a calpain inhibitor, was utilized in a canine AF model.Methods Fifteen dogs were randomly divided into 3 groups: sham-operated group, control group and calpain inhibitor group; each with 5 dogs. Sustained AF was induced by rapid right atrium pacing at 600 beats per minute for 3 weeks. ALLM was administered at a dosage of 1.0 mg-kg-1·d-1 in the calpain inhibitor group. Three weeks later, the proteolysis, protein expression of TnT and myosin, calpain l localization and expression and structural changes were examined in left atrial free walls, right atrial free walls and the interatrial septum respectively. Atrial size and contractile function were also measured by echocardiography.Results Long-term rapid atrial pacing induced marked structural changes such as enlarged atrial volume, myolysis, degradation of TnT and myosin, accumulation of glycogen and changes in mitochondrial shape and size, which were paralleled by an increase in calpain activity. The positive correlation between calpain activity and the degree of myolysis (rs=0.90 961, P<0.0001) was demonstrated. In addition to structural abnormalities, pacing-induced atrial contractile dysfunction was observed in this study. The pacing-induced atrial structural alterations and loss of contractility were partially prevented by the calpain inhibitor ALLM.Conclusions Activation of calpain represents key features in the progression towards overt structural remodeling. Calpain inhibitor, ALLM, suppressed the increased calpain activity and reversed structural remodeling caused by sustained atrial fibrillation in the present model. Calpain Inhibition may therefore provide a possibility for therapeutic Intervention in AF.

  3. Presence of accessory left atrial appendage/diverticula in a population with atrial fibrillation compared with those in sinus rhythm: a retrospective review.

    Science.gov (United States)

    Troupis, John; Crossett, Marcus; Scneider-Kolsky, Michal; Nandurkar, Dee

    2012-02-01

    Accessory left atrial appendages and atrial diverticula have an incidence of 10-27%. Their association with atrial fibrillation needs to be confirmed. This study determined the prevalence, number, size, location and morphology of accessory left atrial appendages/atrial diverticula in patients with atrial fibrillation compared with those in sinus rhythm. A retrospective analysis of 47 consecutive patients with atrial fibrillation who underwent 320 multidetector Coronary CT angiography (CCTA) was performed. A random group of 47 CCTA patients with sinus rhythm formed the control group. The presence, number, size, location and morphology of accessory left atrial appendages and atrial diverticula in each group were analysed. Twenty one patients had a total of 25 accessory left atrial appendages and atrial diverticula in the atrial fibrillation group and 22 patients had a total of 24 accessory left atrial appendages and atrial diverticula in the sinus rhythm group. Twenty-one atrial diverticula were identified in 19 patients in the atrial fibrillation group and 19 atrial diverticula in 17 patients in the sinus rhythm group. The mean length and width of accessory left atrial appendage was 6.9 and 4.7 mm, respectively in the atrial fibrillation group and 12 and 4.6 mm, respectively, in the sinus rhythm group, P = ns (not significant). The mean length and width of atrial diverticulum was 4.7 and 3.6 mm, respectively in the atrial fibrillation group and 6.2 and 5 mm, respectively in the sinus rhythm group (P = ns). Eighty-four % and 96% of the accessory left atrial appendages/atrial diverticula in the atrial fibrillation and sinus rhythm groups were located along the right anterosuperior left atrial wall. Accessory left atrial appendages and atrial diverticula are common structures with similar prevalence in patients with atrial fibrillation and sinus rhythm.

  4. [Anticoagulation in atrial fibrillation - an update].

    Science.gov (United States)

    Antz, Matthias; Hullmann, Bettina; Neufert, Christian; Vocke, Wolfgang

    2008-12-01

    The correct anticoagulation regimen for prevention of thromboembolic events is essential in patients with atrial fibrillation. However, only a minority of patients receives anticoagulation according to the guidelines. The current guidelines are intended to make the indication for anticoagulation more simple and are summarized in the present article. This includes recommendations for chronic anticoagulation, prevention of thromboembolic events after cardioversion and in ablation of atrial fibrillation.

  5. Inhibition of small-conductance Ca2+-activated K+ channels terminates and protects against atrial fibrillation

    DEFF Research Database (Denmark)

    Diness, Jonas Goldin; Sørensen, Ulrik S; Nissen, Jakob Dahl

    2010-01-01

    Recently, evidence has emerged that small-conductance Ca(2+)-activated K(+) (SK) channels are predominantly expressed in the atria in a number of species including human. In rat, guinea pig, and rabbit ex vivo and in vivo models of atrial fibrillation (AF), we used 3 different SK channel inhibito...

  6. Brugada syndrome risk loci seem protective against atrial fibrillation

    DEFF Research Database (Denmark)

    Andreasen, Laura; Nielsen, Jonas B; Darkner, Stine;

    2014-01-01

    Several studies have shown an overlap between genes involved in the pathophysiological mechanisms of atrial fibrillation (AF) and Brugada Syndrome (BrS). We investigated whether three single-nucleotide polymorphisms (SNPs) (rs11708996; G>C located intronic to SCN5A, rs10428132; T>G located in SCN10...... associated with BrS was lower in AF patients than in patients free of AF, suggesting a protective role of these loci in developing AF.European Journal of Human Genetics advance online publication, 26 March 2014; doi:10.1038/ejhg.2014.46....

  7. A new method for internal cardioversion in patients with persistent atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Atrial fibrillation (AF), a common arrhythmia in clinical practice, is associated with hemodynamic impairment of cardiac function, increased risk of serious thromboembolic events,1 and 1.5 to 1.8 times increased mortality.2 Restoration of sinus rhythm is the desirable end point in patients with AF. Transthoracic electrical cardioversion is currently a safe and effective method to restore sinus rhythm, yet its efficacy is limited, especially in cases with AF duration more than 36 months and left atrial size more than 60 mm.3-5 Studies in animals and humans have shown that internal cardioversion has a higher success rate compared to that of transthoracic cardioversion.6-8 We present two special cases with atrial fibrillation of long duration or refractory to transthoracic cardioversion that were successfully converted by a newly developed low energy internal cardioversion technique.

  8. RR-Interval variance of electrocardiogram for atrial fibrillation detection

    Science.gov (United States)

    Nuryani, N.; Solikhah, M.; Nugoho, A. S.; Afdala, A.; Anzihory, E.

    2016-11-01

    Atrial fibrillation is a serious heart problem originated from the upper chamber of the heart. The common indication of atrial fibrillation is irregularity of R peak-to-R-peak time interval, which is shortly called RR interval. The irregularity could be represented using variance or spread of RR interval. This article presents a system to detect atrial fibrillation using variances. Using clinical data of patients with atrial fibrillation attack, it is shown that the variance of electrocardiographic RR interval are higher during atrial fibrillation, compared to the normal one. Utilizing a simple detection technique and variances of RR intervals, we find a good performance of atrial fibrillation detection.

  9. Predictors of left atrial appendage stunning after electrical cardioversion of non-valvular atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    杨沙宁; 黄从新; 胡晓军; 金立军; 李凤翥; 彭水先

    2003-01-01

    Objective To identify predictors of left atrial appendage stunning after the use of electrical cardioversion to restore sinus rhythm in patients with non-valvular atrial fibrillation.Methods A total of 68 consecutive patients (45 men, 23 women, 60.5±8.7 years of age) with non-valvular atrial fibrillation undergoing electrical cardioversion were enlisted in this study. Clinical and echocardiographic variables were analyzed by univariate regression and multivariate logistic regression to investigate the relationship between occurrences of left atrial appendage stunning and these factors. Results Univariate analysis revealed that, in comparing patients without and with left atrial appendage stunning, there were significant differences in the duration of atrial fibrillation > 8 weeks (32.3% vs 75.5%, P 50 mm (29.0% vs 54.1%, P 8 weeks (OR=7.249, 95%CI=1.998-26.304, P 50 mm (OR=3.896, 95%CI=1.105-13.734, P8 weeks, left atrial diameter >50 mm, left ventricular ejection fraction <50%, and cumulative energy of electrical cardioversion are independent predictors of left atrial appendage stunning. Anticoagulation treatment should be individualized for patients undergoing electrical cardioversion to reduce the risk of both cardioversion-related thromboembolic events and hemorrhagic complications caused by warfarin treatment.

  10. Efficacy and safety of intravenous dofetilide for rapid termination of atrial fibrillation and atrial flutter

    NARCIS (Netherlands)

    Kingma, JH; Crijns, HJGM; Dunselman, PHJM

    2000-01-01

    Dofetilide may be advantageous in terminating atrial fibrillation/atrial flutter (AFl) when there are contraindications for class I drugs (left ventricular dysfunction and/or manifest myocardial ischemia) and beta blockers. In particular, its successful outcome in usually drug-resistant AFl is promi

  11. Prednisone prevents atrial fibrillation promotion by atrial tachycardia remodeling in dogs

    NARCIS (Netherlands)

    Shiroshita-Takeshita, A; Brundel, BJJM; Lavoie, J; Nattel, S

    2006-01-01

    Background: There is evidence suggesting involvement of oxidative stress, inflammation, and calcineurin/nuclear factor of activated T cell pathways in atrial fibrillation. This study evaluated the efficacy of anti-inflammatory and calcineurin-inhibitory drugs on promotion of atrial fibrillation by a

  12. Effect of age on stroke prevention therapy in patients with atrial fibrillation: the atrial fibrillation investigators

    DEFF Research Database (Denmark)

    van Walraven, Carl; Hart, Robert G; Connolly, Stuart

    2009-01-01

    on the relative efficacy of oral anticoagulants (OAC) and antiplatelet (AP) therapy (including acetylsalicylic acid and triflusal) on ischemic stroke, serious bleeding, and vascular events in patients with atrial fibrillation. METHODS: This is an analysis of the Atrial Fibrillation Investigators database, which...

  13. The dark side is not fastidious--dark septate endophytic fungi of native and invasive plants of semiarid sandy areas.

    Science.gov (United States)

    Knapp, Dániel G; Pintye, Alexandra; Kovács, Gábor M

    2012-01-01

    Dark septate endophytic (DSE) fungi represent a frequent root-colonizing fungal group common in environments with strong abiotic stress, such as (semi)arid ecosystems. This work aimed to study the DSE fungi colonizing the plants of semiarid sandy grasslands with wood steppe patches on the Great Hungarian Plain. As we may assume that fungi colonizing both invasive and native species are generalists, root associated fungi (RAF) were isolated from eight native and three invasive plant species. The nrDNA sequences of the isolates were used for identification. To confirm that the fungi were endophytes an artificial inoculation system was used to test the isolates: we considered a fungus as DSE if it colonized the roots without causing a negative effect on the plant and formed microsclerotia in the roots. According to the analyses of the ITS sequence of nrDNA the 296 isolates clustered into 41 groups. We found that 14 of these 41 groups were DSE, representing approximately 60% of the isolates. The main DSE groups were generalist and showed no specificity to area or season and colonized both native and invasive species, demonstrating that exotic plants are capable of using the root endophytic fungi of the invaded areas. The DSE community of the region shows high similarity to those found in arid grasslands of North America. Taking into account a previous hypothesis about the common root colonizers of those grasslands and our results reported here, we hypothesize that plants of (semi)arid grasslands share common dominant members of the DSE fungal community on a global scale.

  14. The potential of Dark Septate Endophytes to form root symbioses with ectomycorrhizal and ericoid mycorrhizal middle European forest plants.

    Directory of Open Access Journals (Sweden)

    Tereza Lukešová

    Full Text Available The unresolved ecophysiological significance of Dark Septate Endophytes (DSE may be in part due to existence of morphologically indistinguishable cryptic species in the most common Phialocephala fortinii s. l.--Acephala applanata species complex (PAC. We inoculated three middle European forest plants (European blueberry, Norway spruce and silver birch with 16 strains of eight PAC cryptic species and other DSE and ectomycorrhizal/ericoid mycorrhizal fungi and focused on intraradical structures possibly representing interfaces for plant-fungus nutrient transfer and on host growth response. The PAC species Acephala applanata simultaneously formed structures resembling ericoid mycorrhiza (ErM and DSE microsclerotia in blueberry. A. macrosclerotiorum, a close relative to PAC, formed ectomycorrhizae with spruce but not with birch, and structures resembling ErM in blueberry. Phialocephala glacialis, another close relative to PAC, formed structures resembling ErM in blueberry. In blueberry, six PAC strains significantly decreased dry shoot biomass compared to ErM control. In birch, one A. macrosclerotiorum strain increased root biomass and the other shoot biomass in comparison with non-inoculated control. The dual mycorrhizal ability of A. macrosclerotiorum suggested that it may form mycorrhizal links between Ericaceae and Pinaceae. However, we were unable to detect this species in Ericaceae roots growing in a forest with presence of A. macrosclerotiorum ectomycorrhizae. Nevertheless, the diversity of Ericaceae mycobionts was high (380 OTUs with individual sites often dominated by hitherto unreported helotialean and chaetothyrialean/verrucarialean species; in contrast, typical ErM fungi were either absent or low in abundance. Some DSE apparently have a potential to form mycorrhizae with typical middle European forest plants. However, except A. applanata, the tested representatives of all hitherto described PAC cryptic species formed typical DSE

  15. The potential of Dark Septate Endophytes to form root symbioses with ectomycorrhizal and ericoid mycorrhizal middle European forest plants.

    Science.gov (United States)

    Lukešová, Tereza; Kohout, Petr; Větrovský, Tomáš; Vohník, Martin

    2015-01-01

    The unresolved ecophysiological significance of Dark Septate Endophytes (DSE) may be in part due to existence of morphologically indistinguishable cryptic species in the most common Phialocephala fortinii s. l.--Acephala applanata species complex (PAC). We inoculated three middle European forest plants (European blueberry, Norway spruce and silver birch) with 16 strains of eight PAC cryptic species and other DSE and ectomycorrhizal/ericoid mycorrhizal fungi and focused on intraradical structures possibly representing interfaces for plant-fungus nutrient transfer and on host growth response. The PAC species Acephala applanata simultaneously formed structures resembling ericoid mycorrhiza (ErM) and DSE microsclerotia in blueberry. A. macrosclerotiorum, a close relative to PAC, formed ectomycorrhizae with spruce but not with birch, and structures resembling ErM in blueberry. Phialocephala glacialis, another close relative to PAC, formed structures resembling ErM in blueberry. In blueberry, six PAC strains significantly decreased dry shoot biomass compared to ErM control. In birch, one A. macrosclerotiorum strain increased root biomass and the other shoot biomass in comparison with non-inoculated control. The dual mycorrhizal ability of A. macrosclerotiorum suggested that it may form mycorrhizal links between Ericaceae and Pinaceae. However, we were unable to detect this species in Ericaceae roots growing in a forest with presence of A. macrosclerotiorum ectomycorrhizae. Nevertheless, the diversity of Ericaceae mycobionts was high (380 OTUs) with individual sites often dominated by hitherto unreported helotialean and chaetothyrialean/verrucarialean species; in contrast, typical ErM fungi were either absent or low in abundance. Some DSE apparently have a potential to form mycorrhizae with typical middle European forest plants. However, except A. applanata, the tested representatives of all hitherto described PAC cryptic species formed typical DSE colonization without

  16. Control of Verticillium Yellows in Chinese Cabbage by the Dark Septate Endophytic Fungus LtVB3.

    Science.gov (United States)

    Narisawa, K; Usuki, F; Hashiba, T

    2004-05-01

    ABSTRACT Three hundred forty-nine fungal endophytes were obtained from a total of 1,214 root segments of eggplant, melon, barley, and Chinese cabbage grown as bait plants in a mixed soil made up of samples from different forest soils in Alberta and British Columbia, Canada. Three of the 349 isolates, when inoculated in axenically reared Chinese cabbage seedlings grown in petri dishes, almost completely suppressed the effects of a postinoculated and virulent strain of Verticillium longisporum. Two isolates effective against the pathogen were Phialocephala fortinii, which had been obtained from the roots of eggplant and Chinese cabbage. The third isolate was a dark septate endophytic (DSE) fungus obtained from barley roots. Hyphae of P. fortinii grew along the surface of the root and formed microsclerotia on or in the epidermal layer. Hyphae of the DSE fungus heavily colonized root cells of the cortex. Seedlings grown for 1 week in the presence of the endophytes were then challenged with the Verticillium pathogen. In DSE-treated roots, some of cell walls in the epidermal and cortical layers showed cell wall appositions and thickenings, which appeared to limit the ingress of the pathogen into adjacent cells. Such marked host reactions were not observed in the root cells colonized by P. fortinii. Chinese cabbage preinoculated with the above endophytes and, for comparison, a previously reported disease-suppressive fungal endophyte, Heteroconium chaetospira, were transplanted into the field and disease symptoms were assessed. The DSE could most effectively inhibit the development of Verticillium yellows, with reductions in the percentages of external and internal disease symptoms of 84 and 88%, respectively. The protective values against the disease are extremely high compared with those of other isolates. Most of the DSE-treated plants in the plots achieved marketable quality.

  17. Contrasting impacts of defoliation on root colonization by arbuscular mycorrhizal and dark septate endophytic fungi of Medicago sativa.

    Science.gov (United States)

    Saravesi, K; Ruotsalainen, A L; Cahill, J F

    2014-05-01

    Individual plants typically interact with multiple mutualists and enemies simultaneously. Plant roots encounter both arbuscular mycorrhizal (AM) and dark septate endophytic (DSE) fungi, while the leaves are exposed to herbivores. AMF are usually beneficial symbionts, while the functional role of DSE is largely unknown. Leaf herbivory may have a negative effect on root symbiotic fungi due to decreased carbon availability. However, evidence for this is ambiguous and no inoculation-based experiment on joint effects of herbivory on AM and DSE has been done to date. We investigated how artificial defoliation impacts root colonization by AM (Glomus intraradices) and DSE (Phialocephala fortinii) fungi and growth of Medicago sativa host in a factorial laboratory experiment. Defoliation affected fungi differentially, causing a decrease in arbuscular colonization and a slight increase in DSE-type colonization. However, the presence of one fungal species had no effect on colonization by the other or on plant growth. Defoliation reduced plant biomass, with this effect independent of the fungal treatments. Inoculation by either fungal species reduced root/shoot ratios, with this effect independent of the defoliation treatments. These results suggest AM colonization is limited by host carbon availability, while DSE may benefit from root dieback or exudation associated with defoliation. Reductions in root allocation associated with fungal inoculation combined with a lack of effect of fungi on plant biomass suggest DSE and AMF may be functional equivalent to the plant within this study. Combined, our results indicate different controls of colonization, but no apparent functional consequences between AM and DSE association in plant roots in this experimental setup.

  18. Determinants of Left Atrial Volume in Patients with Atrial Fibrillation

    Science.gov (United States)

    Hochgruber, Thomas; Krisai, Philipp; Zimmermann, Andreas J.; Aeschbacher, Stefanie; Pumpol, Katrin; Kessel-Schaefer, Arnheid; Stephan, Frank-Peter; Handschin, Nadja; Sticherling, Christian; Osswald, Stefan; Kaufmann, Beat A.; Paré, Guillaume; Kühne, Michael; Conen, David

    2016-01-01

    Introduction Left atrial (LA) enlargement is an important risk factor for incident stroke and a key determinant for the success of rhythm control strategies in patients with atrial fibrillation (AF). However, factors associated with LA volume in AF patients remain poorly understood. Methods Patients with paroxysmal or persistent AF were enrolled in this study. Real time 3-D echocardiography was performed in all participants and analyzed offline in a standardized manner. We performed stepwise backward linear regression analyses using a broad set of clinical parameters to determine independent correlates for 3-D LA volume. Results We included 210 patients (70.9% male, mean age 61±11years). Paroxysmal and persistent AF were present in 95 (45%) and 115 (55%) patients, respectively. Overall, 115 (55%) had hypertension, 11 (5%) had diabetes, and 18 (9%) had ischemic heart disease. Mean indexed LA volume was 36±12ml/m2. In multivariable models, significant associations were found for female sex (β coefficient -10.51 (95% confidence interval (CI) -17.85;-3.16), p = 0.0053), undergoing cardioversion (β 11.95 (CI 5.15; 18.74), p = 0.0006), diabetes (β 14.23 (CI 2.36; 26.10), p = 0.019), body surface area (BSA) (β 34.21 (CI 19.30; 49.12), pglomerular filtration rate (β -0.21 (CI -0.36; -0.06), p = 0.0064) and plasma levels of NT-pro brain natriuretic peptide (NT-proBNP) (β 6.79 (CI 4.05; 9.52), p<0.0001), but not age (p = 0.59) or hypertension (p = 0.42). Our final model explained 52% of the LA volume variability. Conclusions In patients with AF, the most important correlates with LA volume are sex, BSA, diabetes, renal function and NT-proBNP, but not age or hypertension. These results may help to refine rhythm control strategies in AF patients. PMID:27701468

  19. Outcomes after ablation for typical atrial flutter (from the Loire Valley Atrial Fibrillation Project).

    Science.gov (United States)

    Clementy, Nicolas; Desprets, Laurent; Pierre, Bertrand; Lallemand, Bénédicte; Simeon, Edouard; Brunet-Bernard, Anne; Babuty, Dominique; Fauchier, Laurent

    2014-11-01

    Similar predisposing factors are found in most types of atrial arrhythmias. The incidence of atrial fibrillation (AF) among patients with atrial flutter is high, suggesting similar outcomes in patients with those arrhythmias. We sought to investigate the long-term outcomes and prognostic factors of patients with AF and/or atrial flutter with contemporary management using radiofrequency ablation. In an academic institution, we retrospectively examined the clinical course of 8,962 consecutive patients admitted to our department with a diagnosis of AF and/or atrial flutter. After a median follow-up of 934 ± 1,134 days, 1,155 deaths and 715 stroke and/thromboembolic (TE) events were recorded. Patients with atrial flutter undergoing cavotricuspid isthmus ablation (n = 875, 37% with a history of AF) had a better survival rate than other patients (hazard ratio [HR] 0.35, 95% confidence interval [CI] 0.25 to 0.49, p <0.0001). Using Cox proportional hazards model and propensity score model, after adjustment for main other confounders, ablation for atrial flutter was significantly associated with a lower risk of all-cause mortality (HR 0.55, 95% CI 0.36 to 0.84, p = 0.006) and stroke and/or TE events (HR 0.53, 95% CI 0.30 to 0.92, p = 0.02). After ablation, there was no significant difference in the risk of TE between patients with a history of AF and those with atrial flutter alone (HR 0.83, 95% CI 0.41 to 1.67, p = 0.59). In conclusion, in patients with atrial tachyarrhythmias, those with atrial flutter with contemporary management who undergo cavotricuspid isthmus radiofrequency ablation independently have a lower risk of stroke and/or TE events and death of any cause, whether a history of AF is present or not.

  20. Atrial strain rate is a sensitive measure of alterations in atrial phasic function in healthy ageing.

    Science.gov (United States)

    Boyd, Anita C; Richards, David A B; Marwick, Thomas; Thomas, Liza

    2011-09-01

    Strain and strain rate measure local deformation of the myocardium and have been used to evaluate phasic atrial function in various disease states. The aim of this study was to define normal values for tissue Doppler-derived atrial strain measurements and examine age-related changes by decade in healthy individuals. Transthoracic echocardiograms were performed on 188 healthy subjects. Tissue Doppler-derived strain and strain rate were measured from the apical four and two-chamber views of the left atrium, and global values were calculated as the mean of all segments. Measurements included peak systolic strain, systolic strain rate, early and late diastolic strain rate. Phasic left atrial volumes and fractions were calculated. Mitral inflow and tissue Doppler imaging were employed to estimate left ventricular diastolic function. A significant reduction in global systolic strain was observed from decade 6. Alterations in atrial strain rate were apparent from decade 5; systolic strain rate and early diastolic strain rate decreased, while late diastolic strain rate increased significantly. Changes in phasic atrial volume and function occurred in conjunction with age-related changes in left ventricular diastolic function. Importantly, age-related changes in global atrial systolic strain rate and early diastolic strain rate occurred a decade before corresponding changes in atrial phasic volume parameters. Atrial strain and strain rate can be used to quantify atrial phasic function and appear to be altered before traditional parameters with ageing. Strain analysis may therefore be more sensitive in detecting subclinical atrial dysfunction with alterations in strain rate parameters observed before traditional parameters.

  1. Mechanism for Triggered Waves in Atrial Myocytes.

    Science.gov (United States)

    Shiferaw, Yohannes; Aistrup, Gary L; Wasserstrom, J Andrew

    2017-08-08

    Excitation-contraction coupling in atrial cells is mediated by calcium (Ca) signaling between L-type Ca channels and Ryanodine receptors that occurs mainly at the cell boundary. This unique architecture dictates essential aspects of Ca signaling under both normal and diseased conditions. In this study we apply laser scanning confocal microscopy, along with an experimentally based computational model, to understand the Ca cycling dynamics of an atrial cell subjected to rapid pacing. Our main finding is that when an atrial cell is paced under Ca overload conditions, Ca waves can then nucleate on the cell boundary and propagate to the cell interior. These propagating Ca waves are referred to as "triggered waves" because they are initiated by L-type Ca channel openings during the action potential. These excitations are distinct from spontaneous Ca waves originating from random fluctuations of Ryanodine receptor channels, and which occur after much longer waiting times. Furthermore, we argue that the onset of these triggered waves is a highly nonlinear function of the sarcoplasmic reticulum Ca load. This strong nonlinearity leads to aperiodic response of Ca at rapid pacing rates that is caused by the complex interplay between paced Ca release and triggered waves. We argue further that this feature of atrial cells leads to dynamic instabilities that may underlie atrial arrhythmias. These studies will serve as a starting point to explore the nonlinear dynamics of atrial cells and will yield insights into the trigger and maintenance of atrial fibrillation. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  2. Risk of atrial fibrillation and stroke in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Lindhardsen, Jesper; Ahlehoff, Ole; Gislason, Gunnar Hilmar;

    2012-01-01

    To determine if patients with rheumatoid arthritis have increased risk of atrial fibrillation and stroke.......To determine if patients with rheumatoid arthritis have increased risk of atrial fibrillation and stroke....

  3. Management and prognosis of atrial fibrillation in the diabetic patient

    DEFF Research Database (Denmark)

    Pallisgaard, Jannik Langtved; Lindhardt, Tommi Bo; Olesen, Jonas Bjerring

    2015-01-01

    The global burden of atrial fibrillation and diabetes mellitus (diabetes) is considerable, and prevalence rates are increasing. Diabetes is associated with an increased risk of developing atrial fibrillation; however, diabetes also influences the management and prognosis of atrial fibrillation. I...... and outcomes of heart failure and the success rates of both ablation and cardioversion in atrial fibrillation patients with diabetes. Finally, this article describes the association of HbA1c levels with the management and prognosis of atrial fibrillation patients.......The global burden of atrial fibrillation and diabetes mellitus (diabetes) is considerable, and prevalence rates are increasing. Diabetes is associated with an increased risk of developing atrial fibrillation; however, diabetes also influences the management and prognosis of atrial fibrillation...

  4. Giant right atrial myxoma: characterization with cardiac magnetic resonance imaging.

    LENUS (Irish Health Repository)

    Ridge, Carole A

    2012-02-01

    A 53-year-old woman presented to the emergency department with a 2-week history of dyspnoea and chest pain. Computed tomography pulmonary angiography was performed to exclude acute pulmonary embolism (PE). This demonstrated a large right atrial mass and no evidence of PE. Transthoracic echocardiography followed by cardiac magnetic resonance imaging confirmed a mobile right atrial mass. Surgical resection was then performed confirming a giant right atrial myxoma. We describe the typical clinical, radiologic, and pathologic features of right atrial myxoma.

  5. Gene expression of the natriuretic peptide system in atrial tissue of patients with paroxysmal and persistent atrial fibrillation

    NARCIS (Netherlands)

    Tuinenburg, AE; Brundel, BJJM; Van Gelder, IC; Henning, RH; Van den Berg, MP; Driessen, C; Grandjean, JG; Van Gilst, WH; Crijns, HJGM

    1999-01-01

    Natriuretic Peptide System in AF. Introduction: Circulating cardiac natriuretic peptides play an important role in maintaining volume homeostasis, especially during conditions affecting hemodynamics. During atrial fibrillation (AF), levels of plasma atrial natriuretic peptide (ANP) becomes elevated.

  6. Interobserver variation in interpretation of electrocardiographic signs of atrial infarction

    DEFF Research Database (Denmark)

    Christensen, J H; Nielsen, F E; Falstie-Jensen, N

    1993-01-01

    The electrocardiogram (ECG) is the only means of diagnosing atrial infarction antemortem. Certain ECG changes (PR-segment displacements) have been taken earlier as signs of atrial infarction. The purpose of this study was to assess the interobserver variation on suggested ECG signs of atrial infa...

  7. Autonomic and surgical substrate modulation of atrial fibrillation

    NARCIS (Netherlands)

    Krul, S.P.J.

    2016-01-01

    This thesis focuses on the effects of fibrosis and the autonomic nervous system on conduction in patients with atrial fibrillation and the surgical ablation of the atria and autonomic nervous system as treatment of atrial fibrillation. Atrial fibrillation is the most common arrhythmia and results fr

  8. Atrial electromechanical delay in patients undergoing heart transplantation

    Directory of Open Access Journals (Sweden)

    Mustafa Bulut, MD

    2017-04-01

    Conclusion: Inter-AEMD and intra-AEMD were prolonged in patients who underwent heart transplantation as compared to a control population. This may explain the increased atrial fibrillation and other atrial arrhythmia incidences associated with the biatrial anastomosis heart transplantation technique and may contribute to the treatment of atrial fibrillation in this special patient group.

  9. Surgical Treatment of Atrial Fibrillation: A Review

    Directory of Open Access Journals (Sweden)

    Nadine Hiari

    2011-01-01

    Full Text Available Atrial fibrillation is the most commonly sustained arrhythmia in man. While it affects millions of patients worldwide, its incidence will markedly increase with an aging population. Primary goals of AF therapy are to (1 reduce embolic complications, particularly stroke, (2 alleviate symptoms, and (3 prevent long-term heart remodelling. These have been proven to be a challenge as there are major limitations in our knowledge of the pathological and electrophysiological mechanisms underlying AF. Although advances continue to be made in the medical management of this condition, pharmacotherapy is often unsuccessful. Because of the high recurrence rate of AF despite antiarrhythmic drug therapy for maintenance of sinus rhythm and the adverse effects of these drugs, there has been growing interest in nonpharmacological strategies. Surgery for treatment of AF has been around for some time. The Cox-Maze procedure is the gold standard for the surgical treatment of atrial fibrillation and has more than 90% success in eliminating atrial fibrillation. Although the cut and sew maze is very effective, it has been superseded by newer operations that rely on alternate energy sources to create lines of conduction block. In addition, the evolution of improved ablation technology and instrumentation has facilitated the development of minimally invasive approaches. In this paper, the rationale for surgical ablation for atrial fibrillation and the different surgical techniques that were developed will be explored. In addition, it will detail the new approaches to surgical ablation of atrial fibrillation that employ alternate energy sources.

  10. GENETIC PREDICTORS OF ATRIAL FIBRILLATION

    Directory of Open Access Journals (Sweden)

    A. V. Kuskaeva

    2016-01-01

    Full Text Available Atrial fibrillation (AF is the most common heart rhythm disturbance. It is believed that the primary form of AF is genetically determined in most cases, but the genetic component cannot be excluded in the secondary form of AF. AF is a heterogeneous disease and many authors proved its relationship with other genetic heart disease. In most cases, certain combinations of polymorphisms of different genes promote the development of AF. The study of genes of renin-angiotensin-aldosterone system (RAAS is especially important, because the role of this system in AF pathogenesis is currently studding most intensively. These studies are of great practical interest, as associative effect of angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists in the prevention of AF is revealed. RAAS blockers are able not only to reduce the risk of new-onset AF in hypertensive and normotensive patients but also prevent recurrence of AF. Furthermore, experimental studies showed that RAAS blockers prevent not only the remodeling of the left ventricle, and also the left atrium, pointing to the pathogenesis of AF. So, screening for susceptibility genes and the study of their polymorphism is currently an important focus in the study of AF.

  11. The effect of atrial preference pacing on atrial fibrillation electrophysiological substrate in Myotonic Dystrophy type 1 population

    OpenAIRE

    Russo, Vincenzo; NIGRO, GERARDO; DI MEO, FEDERICA; PAPA, ANDREA ANTONIO; CIOPPA, NADIA DELLA; PROIETTI, RICCARDO; Russo, Maria Giovanna; Calabrò, Raffaele; Politano, Luisa

    2014-01-01

    P-wave dispersion is a non invasive indicator of intra-atrial conduction heterogeneity producing substrate for reentry, which is a pathophysiological mechanism of atrial fibrillation. The relationship between P-wave dispersion (PD) and atrial fibrillation (AF) in Myotonic dystrophy type 1 (DM1) patients is still unclear. Atrial Preference Pacing (APP) is an efficient algorithm to prevent paroxysmal AF in patients implanted with dual-chamber pacemaker. Aim of our study was to evaluate the poss...

  12. Pulmonary vein isolation in the treatment of atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Kumar S

    2016-05-01

    Full Text Available Saurabh Kumar, Gregory F Michaud Cardiac Arrhythmia Service, Cardiovascular Division, Brigham and Women's Hospital, Boston, MA, USA Abstract: Atrial fibrillation (AF is the commonest arrhythmia in humans and is associated with marked reduction in quality of life and an elevated thromboembolic risk. Paroxysmal, persistent, and permanent forms of AF have been recognized. Whilst antiarrhythmic drugs are considered as first-line therapy, the role of catheter ablation is increasing due to its superior efficacy in terms of quality of life and reduction in AF burden. The central paradigm for catheter ablation of AF is that triggers for AF are located near and within the pulmonary veins (PVs, and electrical isolation of the PVs from the left atrium forms the cornerstone of most catheter ablation strategies. Whilst paroxysmal form is generally trigger dependent, persistent and permanent forms are associated with variable interaction between triggers and "substrate" comprised of atrial and PV electrical and structural remodeling. Nevertheless, isolation of the PVs still forms a critical component of catheter ablation strategies, regardless of AF type. Procedural efficacy, however, is limited by PV conduction recovery. This is likely due to deficiencies in ablation tools or limitations of intraprocedural assessment of lesion efficacy. Careful attention to surrogates of tissue heating, such as impedance decrease and electrogram morphology changes, along with advances in catheter technology like contact force catheters may improve rates of durable PV isolation and single-procedural success. This review discusses the mechanism of paroxysmal AF with particular focus on the role of the PVs in AF initiation and PV isolation in the management of AF. Keywords: contact force, lesion transmurality, radiofrequency catheter ablation, paroxysmal atrial fibrillation, electrophysiology, AF

  13. From delirium cordis to atrial fibrillation: historical development of a disease concept.

    Science.gov (United States)

    Flegel, K M

    1995-06-01

    In 1874, the electrical stimulation of animal hearts made known the existence of atrial fibrillation, but atrial fibrillation was not associated with its clinical counterpart, arrhythmia perpetua, until 1909, by which time simultaneous recordings of the human heartbeat, the venous and arterial pulses, and electrocardiographic activity had revealed the common origin of these events. After the electrical basis of atrial fibrillation was found and after atrial fibrillation was clearly distinguished from ventricular fibrillation, investigation into its mechanism ensued. Two contrasting theories, that of circus movement and that of tachysystole from a single focus, led to 30 years of research and debate. Pivotal to the argument was the notion of blocked conduction. Although the theory of circus movement prevailed for a long time, it appeared to be demolished by electrophysiologic experiments done between 1948 and 1950. The realization that blocked conduction could later reenter led to more recent research in animals and humans that revived the notion of circular conduction, although in a much more sophisticated form.

  14. Atrial Model Development and Prototype Simulations: CRADA Final Report on Tasks 3 and 4

    Energy Technology Data Exchange (ETDEWEB)

    O' Hara, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zhang, X. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Villongco, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lightstone, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Richards, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-28

    The goal of this CRADA was to develop essential tools needed to simulate human atrial electrophysiology in 3-dimensions using an anatomical image-based anatomy and physiologically detailed human cellular model. The atria were modeled as anisotropic, representing the preferentially longitudinal electrical coupling between myocytes. Across the entire anatomy, cellular electrophysiology was heterogeneous, with left and right atrial myocytes defined differently. Left and right cell types for the “control” case of sinus rhythm (SR) was compared with remodeled electrophysiology and calcium cycling characteristics of chronic atrial fibrillation (cAF). The effects of Isoproterenol (ISO), a beta-adrenergic agonist that represents the functional consequences of PKA phosphorylation of various ion channels and transporters, was also simulated in SR and cAF to represent atrial activity under physical or emotional stress. Results and findings from Tasks 3 & 4 are described. Tasks 3 and 4 are, respectively: Input parameters prepared for a Cardioid simulation; Report including recommendations for additional scenario development and post-processing analytic strategy.

  15. Fibrosis and electrophysiological characteristics of the atrial appendage in patients with atrial fibrillation and structural heart disease

    NARCIS (Netherlands)

    Brakel, T.J. van; Krieken, T. van der; Westra, S.W.; Laak, J.A.W.M. van der; Smeets, J.L.R.M.; Swieten, H.A. van

    2013-01-01

    PURPOSE: This study was conducted to investigate the degree of fibrosis in atrial appendages of patients with and without atrial fibrillation (AF) undergoing cardiac surgery. In addition, we hypothesized that areas of atrial fibrosis can be identified by electrogram fractionation and low voltage for

  16. Atrial tachycardia originating from the atrial septum in a patient with dextrocardia and complex structural heart disease.

    Science.gov (United States)

    Niu, Ya-Lei; Chang, Shih-Lin; Lin, Yenn-Jiang; Lo, Li-Wei; Hu, Yu-Feng; Lee, Pi-Chang; Chen, Shih-Ann

    2012-10-01

    We report a case with dextrocardia, corrected transposition of the great arteries. He also had an atrial septum defect (ASD) with patch repair. Activation map showed a centrifugal activation from a focal origin on the systemic lower left atrial ASD patch. Ablation of the origin can terminate the atrial tachycardia.

  17. Study on Effect of Compound Salvia Pellet in Preventing Atrial Fibrillation with Left Atrial Thrombosis

    Institute of Scientific and Technical Information of China (English)

    连耀植; 李玉光; 张汉灵; 张元春; 闫纯英; 林建才; 许端敏; 张钰; 郑宝群; 麦芒

    2004-01-01

    @@ Atrial fibrillation (AF) is a kind of common arrhythmia, which, besides affecting cardiac function, has another serious outcome, that is, it is easy to form atrial thrombosis and induce thrombus/embolus, especially cerebral embolus.The incidence of left atrial thrombosis (LAT)could reach 25%-30%(1), the incidence of embolic complication per year could reach 2. 98%-6.30%, even 20% or more(2,3). To prevent thrombosis so as to lower the incidence of cerebral stroke and other embolic complications has been so far the focal point of AF treatment.

  18. Bi-focal atrial tachycardia mimicking atrial fibrillation: fusion and interference between two distinct tachycardias.

    Science.gov (United States)

    Ejima, Koichiro; Shoda, Morio; Tanizaki, Kohei; Kasanuki, Hiroshi

    2007-11-01

    Irregular tachycardias mimicking atrial fibrillation (AF) have previously been described. We report a case of a 60-year-old man with an antiarrhythmic drug-resistant atrial tachycardia (AT) mimicking AF. The tachycardia consisted of two distinct ATs with interference of one repetitive AT with another sustained AT. Radiofrequency (RF) ablation of two distinct right atrial foci eliminated the irregular tachycardia. Although catheter-based pulmonary vein isolation has become a popular therapeutic approach for patients with symptomatic AF, careful evaluation of the intracardiac recordings in the patients undergoing RF ablation for AF is important.

  19. Digoxin versus placebo, no intervention, or other medical interventions for atrial fibrillation and atrial flutter

    DEFF Research Database (Denmark)

    Sethi, Naqash; Safi, Sanam; Feinberg, Joshua

    2017-01-01

    BACKGROUND: Atrial fibrillation is the most common arrhythmia of the heart with a prevalence of approximately 2% in the western world. Atrial flutter, another arrhythmia, occurs less often with an incidence of approximately 200,000 new patients per year in the USA. Patients with atrial fibrillation...... and secondary outcomes, we will create a 'Summary of Findings' table based on GRADE assessments of the quality of the evidence. DISCUSSION: The results of this systematic review have the potential to benefit millions of patients worldwide as well as healthcare economy. SYSTEMATIC REVIEW REGISTRATION: PROSPERO...

  20. Atrial fibrillation associated with subclinical hyperthyroidism.

    Science.gov (United States)

    Patanè, Salvatore; Marte, Filippo

    2009-05-29

    Subclinical hyperthyroidism is an increasingly recognized entity that is defined as a normal serum free thyroxine and free triiodothyronine levels with a thyroid-stimulating hormone level suppressed below the normal range and usually undetectable. It has been reported that subclinical hyperthyroidism is not associated with coronary heart disease or mortality from cardiovascular causes but it is sufficient to induce arrhythmias including atrial fibrillation and atrial flutter. It has also been reported that increased factor X activity in patients with subclinical hyperthyroidism represents a potential hypercoagulable state. We present a case of atrial fibrillation associated with subclinical hyperthyroidism, in a 78-year-old Italian woman. Also this case focuses attention on the importance of a correct evaluation of subclinical hyperthyroidism.

  1. Effects of irbesartan on atrial cell electrophysiology

    Institute of Scientific and Technical Information of China (English)

    HUANG Cong-xin; CAO Feng; JIANG Hong; WANG Teng; LI Xia

    2005-01-01

    @@ Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice.1 Its incidence increases with age and the presence of structural heart disease. It is a major cause of stroke, especially in the elderly. It has been shown that angiotensin converting enzyme inhibitor (ACEI) can reduce the incidence of AF after acute myocardial infarction.2 Several studies have shown that activation of the rennin-angiotensin system is associated with the mechanisms of AF. Irbesartan is a long-acting angiotensin Ⅱ type 1 receptor antagonist used widely in the treatment of hypertension.3 In recent years, it has been demonstrated that patients treated with amiodarone plus irbesartan had a lower rate of recurrence of atrial fibrillation than did patients treated with amiodarone alone.4 These findings suggest that the inhibition of angiotensin Ⅱ may prevent AF, but its underlying electrophysiological mechanisms are obscure. The purpose of this study is to investigate the effects of irbesartan on atrial cell electrophysiology.

  2. Antihypertensive treatment and risk of atrial fibrillation

    DEFF Research Database (Denmark)

    Marott, Sarah C W; Nielsen, Sune F; Benn, Marianne

    2014-01-01

    AIMS: To examine the associations between antihypertensive treatment with angiotensin-converting enzyme inhibitors (ACEis) or angiotensin receptor blockers (ARBs), β-blockers, diuretics, or calcium-antagonists, and risk of atrial fibrillation. We examined these associations using the entire Danish...... population from 1995 through 2010. METHODS AND RESULTS: Excluding medication used in atrial fibrillation, we matched individuals on ACEi monotherapy 1:1 with individuals on β-blocker (n = 48 658), diuretic (n = 69 630), calcium-antagonist (n = 57 646), and ARB monotherapy (n = 20 158). Likewise, individuals...... on ARB monotherapy were matched 1:1 with individuals on β-blocker (n = 20 566), diuretic (n = 20 832), calcium-antagonist (n = 20 232), and ACEi monotherapy (n = 20 158). All were free of atrial fibrillation and of predisposing diseases like heart failure, ischaemic heart disease, diabetes mellitus...

  3. In silico screening of the key cellular remodeling targets in chronic atrial fibrillation.

    Directory of Open Access Journals (Sweden)

    Jussi T Koivumäki

    2014-05-01

    Full Text Available Chronic atrial fibrillation (AF is a complex disease with underlying changes in electrophysiology, calcium signaling and the structure of atrial myocytes. How these individual remodeling targets and their emergent interactions contribute to cell physiology in chronic AF is not well understood. To approach this problem, we performed in silico experiments in a computational model of the human atrial myocyte. The remodeled function of cellular components was based on a broad literature review of in vitro findings in chronic AF, and these were integrated into the model to define a cohort of virtual cells. Simulation results indicate that while the altered function of calcium and potassium ion channels alone causes a pronounced decrease in action potential duration, remodeling of intracellular calcium handling also has a substantial impact on the chronic AF phenotype. We additionally found that the reduction in amplitude of the calcium transient in chronic AF as compared to normal sinus rhythm is primarily due to the remodeling of calcium channel function, calcium handling and cellular geometry. Finally, we found that decreased electrical resistance of the membrane together with remodeled calcium handling synergistically decreased cellular excitability and the subsequent inducibility of repolarization abnormalities in the human atrial myocyte in chronic AF. We conclude that the presented results highlight the complexity of both intrinsic cellular interactions and emergent properties of human atrial myocytes in chronic AF. Therefore, reversing remodeling for a single remodeled component does little to restore the normal sinus rhythm phenotype. These findings may have important implications for developing novel therapeutic approaches for chronic AF.

  4. 房颤对外周血CD34+造血祖细胞的影响 及SDF-1/CXCR4在心房中的表达%Effect of atrial fibrillation on human CD34 + hematopoietic progenitor cells in circulation and expression of SDF-1/CXCR4 in atrium

    Institute of Scientific and Technical Information of China (English)

    李佳; 葛海龙; 陈光远; 高倩萍; 孙俊峰; 李元十; 富路

    2011-01-01

    目的:研究不同类型的房颤(AF)对人外周血CD34+造血祖细胞(CD34+ HPCs)的影响,以及持续心房快速起搏犬心肌基质细胞衍生因子-1(SDF-1)及其受体CXCR4的表达,初步探讨CD34+ HPCs及SDF-1/CXCR4在AF时心肌损伤修复中的作用.方法:应用流式细胞术测定阵发性AF患者组(a=35)、持续性AF患者组(n=35)及窦性心律者对照组(n=30)外周血中CD34+ HPCs的百分含量;并对持续性AF患者组中24例患者成功进行体外直流电复律后48 h,测定外周血中CD34+ HPCs的百分含量.另外,将成年健康杂种犬13条随机分为两组:即快速起搏组(n=7)和假手术组(n=6),均开胸后于右心耳缝植AOO型起搏器,快速起搏组以400次/min起搏6周,假手术组不起搏.应用RT-PCR测定左心耳和左心房CXCR4mRNA的表达水平,用蛋白质免疫印迹法检测左心房SDF-1蛋白的表达.结果:持续性AF患者组外周血中CD34+ HPCs的百分含量明显高于阵发性AF患者组和对照组(P<0.05);而后两组间无差别.持续性AF患者成功进行体外直流电复律后48 h,外周血中CD34+ HPCs的百分含量较复律前明显下降(P<0.05).快速起搏组犬左心耳和左心房CXCR4mRNA表达的水平明显高于假手术组(P<0.05),左心耳增高16.7%,左心房增高18.8%:SDF-1蛋白质表达的水平亦明显高于假手术组(P<0.01).结论:持续性AF患者外周血中CD34 HPCs的数量增加;心房快速起搏犬心房SDF-1/CXCR4的表达增加.CD34+ HPCs和SDF1/CXCR4可能参与了持续性AF患者心房损伤时心肌组织的修复过程.%AIM: To investigate the effect of different kinds of atrial fibrillation (AF) on human CD34 + hematopoietic cells ( HPCs) in circulation and on myocardial expression of SDF-1 and its receptor CXCR4 in canines with lasting rapid atrial pacing and to explore the role of CD34 + HPCs and SDF-1/ CXCR4 in repairing atrium during AF. METHODS; Included in our study were 100 subjects (35 with paroxysmal AF, 35

  5. Cryoballoon Catheter Ablation in Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Cevher Ozcan

    2011-01-01

    Full Text Available Pulmonary vein isolation with catheter ablation is an effective treatment in patients with symptomatic atrial fibrillation refractory or intolerant to antiarrhythmic medications. The cryoballoon catheter was recently approved for this procedure. In this paper, the basics of cryothermal energy ablation are reviewed including its ability of creating homogenous lesion formation, minimal destruction to surrounding vasculature, preserved tissue integrity, and lower risk of thrombus formation. Also summarized here are the publications describing the clinical experience with the cryoballoon catheter ablation in both paroxysmal and persistent atrial fibrillation, its safety and efficacy, and discussions on the technical aspect of the cryoballoon ablation procedure.

  6. The atrial fibrillation ablation pilot study

    DEFF Research Database (Denmark)

    Arbelo, Elena; Brugada, Josep; Hindricks, Gerhard

    2014-01-01

    AIMS: The Atrial Fibrillation Ablation Pilot Study is a prospective registry designed to describe the clinical epidemiology of patients undergoing an atrial fibrillation (AFib) ablation, and the diagnostic/therapeutic processes applied across Europe. The aims of the 1-year follow-up were to analyse...... tachycardia, and 4 patients died (1 haemorrhagic stroke, 1 ventricular fibrillation in a patient with ischaemic heart disease, 1 cancer, and 1 of unknown cause). CONCLUSION: The AFib Ablation Pilot Study provided crucial information on the epidemiology, management, and outcomes of catheter ablation of AFib...

  7. [Obesity as a risk factor for atrial fibrillation].

    Science.gov (United States)

    Duraj, Iwona; Broncel, Marlena

    2016-01-01

    Atrial fibrillation (AF) and obesity is a growing problem of public health both in Poland and in the whole world. AF risk factors may be summarized as elderliness, male sex, smoking, hypertension, diabetes, obesity, coronary heart disease, heart failure, valvular heart disease, cardiac surgery. Once obesity is an independent, potentially modifiable risk factor for AF. The connection between obesity and atrial fibrillation is very up-to-date because of incremental prevalence, almost epidemic of obesity in the whole world. The probability of AF among obese patients increases with concomitant obstructive sleep apnea. Regardless many researches it hasn't been assessed yet how obesity itself predisposes to AF. It could be an effect of change in the atrial anatomy, the rise of atrial pressure, mechanical stretch, interstitial atrial fibrosis and disruption of atrial electric integrity. A great role is ascribed to inflammation, especially proinflammatory cytokines increased by adipocites of left atrial epicardial adiposity.

  8. A rare large right atrial myxoma with rapid growth rate.

    Science.gov (United States)

    Kelly, Shawn C; Steffen, Kelly; Stys, Adam T

    2014-10-01

    Atrial myxomas are the most common benign intracavitary cardiac neoplasms. They most frequently occur in the left atrium. Right atrial tumors are rare, comprising 20 percent of myxomas achieving an incidence of 0.02 percent. Due to their rarity, right atrial tumor development and associated clinical symptoms has not been well described. The classical clinical triad for the presentation of left atrial myxomas--heart failure, embolic events, and constitutional symptoms--may not be applicable to right sided tumors. Also, natural development of myxoma is not well described, as surgical resection is the common practice. Previously ascribed growth rates of myxomas refer mostly to left atrial ones, as right atrial tumors are rare. We present a case of right atrial myxoma with growth rates exceeding those previously described.

  9. New risk factors for atrial fibrillation : causes of 'not-so-lone atrial fibrillation'

    NARCIS (Netherlands)

    Schoonderwoerd, Bas A.; Smit, Marcelle D.; Pen, Lucas; Van Gelder, Isabelle C.

    Atrial fibrillation (AF) is a prevalent arrhythmia in patients with cardiovascular disease. The classical risk factors for developing AF include hypertension, valvular disease, (ischaemic) cardiomyopathy, diabetes mellitus, and thyroid disease. In some patients with AF, no underlying

  10. Left atrial size in patients with cryptogenic stroke as a predictor of occurrence of atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Antonio Cruz Culebras

    2017-04-01

    Full Text Available Objective: To determine whether the left atrial size can predict the development of atrial fibrillation (AF in patients with embolic stroke of undetermined source (ESUS. Methods: Patients with ischemic stroke were included prospectively (January 2015-July 2015 when ESUS was suspected. Clinical and cardiac imaging data were recorded. Patients with cardiac failure were excluded. Results: a total of 55 patients were included. Medium age was 71 years. The proportion of patients who developed AF during the follow-up (1 year was 23, 63%. 10 % of patients did not have any vascular risk factor. Basal ECG was normal in 98% of cases. The left atrial size volume was 36, 08 ml in patients who developed AF and 27, 14 ml in patients who did not. Conclusions: In patients with ESUS, left atrial size dimensions do not predict the occurrence of AF.

  11. New risk factors for atrial fibrillation : causes of 'not-so-lone atrial fibrillation'

    NARCIS (Netherlands)

    Schoonderwoerd, Bas A.; Smit, Marcelle D.; Pen, Lucas; Van Gelder, Isabelle C.

    2008-01-01

    Atrial fibrillation (AF) is a prevalent arrhythmia in patients with cardiovascular disease. The classical risk factors for developing AF include hypertension, valvular disease, (ischaemic) cardiomyopathy, diabetes mellitus, and thyroid disease. In some patients with AF, no underlying (cardiovascular

  12. How to do it: importance of left atrial side retraction in robotic and minimally invasive mitral valve surgery.

    Science.gov (United States)

    Ishikawa, Norihiko; Sun, You Su; Nifong, L Wiley; Watanabe, Go; Chitwood, W Randolph

    2008-01-01

    A customized transthoracic atrial retractor was previously developed for robotic and minimally invasive mitral valve surgery, but it has sometimes failed to provide sufficient exposure of the mitral valve because some atrial tissues push away the operative field from the right side. This report describes 3 new atrial side retractors (the foldaway retractor, the spoon retractor, and the wired retractor) and their use in performing robotic mitral valve repair in fresh frozen human cadavers. These retractors provided exceptional and consistent exposure of the left atrium in robotic and minimally invasive mitral valve surgery in human cadavers without causing traumatic injury, and these retractors should be useful in live patients because they will be used in arrested hearts.

  13. Asymptomatic atrial fibrillation and stroke evaluation in pacemaker patients and the atrial fibrillation reduction atrial pacing trial (ASSERT)

    NARCIS (Netherlands)

    Holnloser, Stefan H.; Capucci, Alessandro; Fain, Eric; Gold, Michael R.; van Gelder, Isabelle C.; Healey, Jeff; Israel, Carsten W.; Lau, Chu P.; Morillo, Carlos; Connolly, Stuart J.

    Asymptomatic atrial fibrillation (AF) is common and may have the same prognostic implications as symptomatic AF. Among patients receiving dual-chamber pacemakers, it is now possible to quantify asymptomatic AF accurately. Most of these episodes are of short duration, often lasting only seconds to

  14. Left atrial appendage occlusion for stroke prevention in atrial fibrillation in Europe

    DEFF Research Database (Denmark)

    Lip, Gregory Y.H.; Dagres, Nikolaos; Proclemer, Alessandro;

    2013-01-01

    The purpose of this EP wire survey was to assess clinical practice in relation to the use of left atrial appendage occlusion (LAAO) devices for stroke prevention in atrial fibrillation (AF) among members of the European Heart Rhythm Association research network. The average number of performed LA...... are most often performed by interventional cardiologists. Experience varied widely, and this was reflected in the wide range of thromboembolic and procedural (tamponade, bleeding) complications reported by the respondents to this EP wire survey....

  15. Computational models of atrial cellular electrophysiology and calcium handling, and their role in atrial fibrillation.

    Science.gov (United States)

    Heijman, Jordi; Erfanian Abdoust, Pegah; Voigt, Niels; Nattel, Stanley; Dobrev, Dobromir

    2016-02-01

    The complexity of the heart makes an intuitive understanding of the relative contribution of ion channels, transporters and signalling pathways to cardiac electrophysiology challenging. Computational modelling of cardiac cellular electrophysiology has proven useful to integrate experimental findings, extrapolate results obtained in expression systems or animal models to other systems, test quantitatively ideas based on experimental data and provide novel hypotheses that are experimentally testable. While the bulk of computational modelling has traditionally been directed towards ventricular bioelectricity, increasing recognition of the clinical importance of atrial arrhythmias, particularly atrial fibrillation, has led to widespread efforts to apply computational approaches to understanding atrial electrical function. The increasing availability of detailed, atrial-specific experimental data has stimulated the development of novel computational models of atrial-cellular electrophysiology and Ca(2+) handling. To date, more than 300 studies have employed mathematical simulations to enhance our understanding of atrial electrophysiology, arrhythmogenesis and therapeutic responses. Future modelling studies are likely to move beyond current whole-cell models by incorporating new data on subcellular architecture, macromolecular protein complexes, and localized ion-channel regulation by signalling pathways. At the same time, more integrative multicellular models that take into account regional electrophysiological and Ca(2+) handling properties, mechano-electrical feedback and/or autonomic regulation will be needed to investigate the mechanisms governing atrial arrhythmias. A combined experimental and computational approach is expected to provide the more comprehensive understanding of atrial arrhythmogenesis that is required to develop improved diagnostic and therapeutic options. Here, we review this rapidly expanding area, with a particular focus on Ca(2+) handling, and

  16. Left atrial appendage closure devices for cardiovascular risk reduction in atrial fibrillation patients

    Directory of Open Access Journals (Sweden)

    Cruz-Gonzalez I

    2015-05-01

    Full Text Available Ignacio Cruz-Gonzalez,* Juan Carlos Rama-Merchan,* Javier Rodriguez-Collado, Javier Martin-Moreiras, Alejandro Diego-Nieto, Antonio Arribas-Jimenez, Pedro Luís SanchezDepartment of Cardiology, University Hospital of Cardiology and IBSAL, Salamanca, Spain *Ignacio Cruz-Gonzalez and Juan Carlos Rama-Merchan have contributed equally to this work and should be considered co-first authors Abstract: Atrial fibrillation (AF is the most common sustained arrhythmia in clinical practice. AF is associated with a 4–5-fold increased risk of stroke and systemic embolism. Oral anticoagulant is the first-line therapy for this purpose, but it has various limitations and is often contraindicated or underutilized. Autopsy and surgical data have suggested that 90% of atrial thrombi in nonvalvular AF patients originate from the left atrial appendage, leading to the development of percutaneous closure for thromboembolic prevention. This paper examines the current evidence on left atrial appendage closure devices for cardiovascular risk reduction in AF patients. Keywords: atrial fibrillation, left atrial appendage, stroke, oral anticoagulant, percutaneous closure, thromboembolic prevention

  17. Percutaneous closure of atrial septal defects leads to normalisation of atrial and ventricular volumes

    Directory of Open Access Journals (Sweden)

    Worthley Matthew I

    2008-12-01

    Full Text Available Abstract Background Percutaneous closure of atrial septal defects (ASDs should potentially reduce right heart volumes by removing left-to-right shunting. Due to ventricular interdependence, this may be associated with impaired left ventricular filling and potentially function. Furthermore, atrial changes post-ASD closure have been poorly understood and may be important for understanding risk of atrial arrhythmia post-ASD closure. Cardiovascular magnetic resonance (CMR is an accurate and reproducible imaging modality for the assessment of cardiac function and volumes. We assessed cardiac volumes pre- and post-percutaneous ASD closure using CMR. Methods Consecutive patients (n = 23 underwent CMR pre- and 6 months post-ASD closure. Steady state free precession cine CMR was performed using contiguous slices in both short and long axis views through the ASD. Data was collected for assessment of left and right atrial, ventricular end diastolic volumes (EDV and end systolic volumes (ESV. Data is presented as mean ± SD, volumes as mL, and paired t-testing performed between groups. Statistical significance was taken as p Results There was a significant reduction in right ventricular volumes at 6 months post-ASD closure (RVEDV: 208.7 ± 76.7 vs. 140.6 ± 60.4 mL, p Conclusion ASD closure leads to normalisation of ventricular volumes and also a reduction in right atrial volume. Further follow-up is required to assess how this predicts outcomes such as risk of atrial arrhythmias after such procedures.

  18. Structural and functional atrial remodeling in patients after catheter and surgical ablation of atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Bockeria L.A.

    2016-03-01

    Full Text Available Atrial fibrillation (AF is the most common supraventricular arrhythmia which occurs in 1.5–2.0% of population. Morbidity of AF increased by 13% over the past two decades. Modern treatment of AF includes drug therapy, catheter radiofrequency ablation and various modifications of Cox Maze operations. The purpose of this review was to assess the atrial remodeling according to world literature. This involved a search of published articles in Medline, Web of Science, PubMed, Cochrane Central Register of Controlled Trials medical databases. During the primary stage of analysis 25 articles of 456 were identified. The researches carried out demonstrate that after catheter ablation and Cox Maze operation in patients with atrial fibrillation left atrium volume decrease, atrial contractile function improvment and sinus rhythm restoration are observed. In the absence of AF recurrence and postoperative atrial arrhythmias in early and late postoperative periods in some patients atrial remodeling is expressed. All data were confirmed by echocardiography, computer tomography and magnetic resonance imaging studies both before and after surgery.

  19. Characteristics of Residual Atrial Posterior Wall and Roof-Dependent Atrial Tachycardias after Pulmonary Vein Isolation.

    Science.gov (United States)

    Matsumoto, Akinori; Fukuzawa, Koji; Kiuchi, Kunihiko; Konishi, Hiroki; Ichibori, Hirotoshi; Imada, Hiroshi; Hyogo, Kiyohiro; Kurose, Jun; Takaya, Tomofumi; Mori, Shumpei; Yoshida, Akihiro; Hirata, Ken-Ichi; Nishii, Tatsuya; Kono, Atsushi

    2016-10-01

    Roof-dependent atrial tachycardia (roof AT) sometimes occurs after pulmonary vein isolation (PVI) of atrial fibrillation (AF). This study aimed to investigate the relationship between the anatomy of the residual left atrial posterior wall and occurrence of roof AT. A total of 265 patients with AF who underwent PVI were enrolled. After the PVI, induced or recurrent roof AT was confirmed by an entrainment maneuver or activation mapping using a three-dimensional (3D) mapping system. To identify the predictors of roof AT, the minimum distance between both PVI lines (d-PVI) was measured by a 3D mapping system and the anatomical parameters, including the left atrial (LA) diameter, left atrial volume index (LAVi), and shape of the left atrial roof, were analyzed by 3D computed tomography. Roof AT was documented in 11 (4.2%) of 265 patients. A multivariable analysis demonstrated that the d-PVI, Deep V shape of the LA roof, and LAVi were associated with roof AT occurrences (d-PVI: odds ratio: 0.72, confidence interval [CI]: 0.61-0.86, P PVI and LAVi, respectively. The shorter d-PVI at the LA roof, greater LAVi, and Deep V shape were associated with the occurrence of a roof AT. © 2016 Wiley Periodicals, Inc.

  20. The effect of asanguinous cardioplegic arrest on atrial preservation using atrial ATP as a marker.

    Science.gov (United States)

    Hines, G L; Scheaffer, P; Williams, L; Mantell, P; Cheifitz, P

    1990-01-01

    Changes in atrial adenosine triphosphate (ATP) and the presence of postoperative arrhythmias were studied in 14 patients during routine coronary artery bypass grafting to 1) attempt to evaluate atrial preservation, and 2) determine if a relationship exists between changes in ATP and the development of postoperative arrhythmias. Atrial biopsies were obtained at the time of cannulation (preischemic sample) and after the removal of the aortic crossclamp (postischemic sample). Methods of myocardial protection included systemic hypothermia (28 degrees C), periodic reinfusion of crystalloid cardioplegia into the aortic root and completed vein grafts, and iced slush in the pericardial well. Atrial temperature was monitored. Preischemic ATP was 0.412 +/- 0.32 mu mol/gm, and the postischemic value was 0.220 +/- 0.13 mu mol/gm (p less than .02). Atrial temperature routinely decreased to 13-18 degrees C after cardioplegic infusion but rose to 24 degrees C between infusions. There was no correlation between postoperative supraventricular arrhythmias (4 patients) and changes in ATP. In conclusion, routine coronary artery bypass grafting with standard methods of cardiac preservation does not appear to satisfactorily preserve atrial tissue. The clinical correlation and significance of this remains to be elucidated.

  1. Atrial Tachycardias Arising from Ablation of Atrial Fibrillation: A Proarrhythmic Bump or an Antiarrhythmic Turn?

    Directory of Open Access Journals (Sweden)

    Ashok J. Shah

    2010-01-01

    Full Text Available The occurrence of atrial tachycardias (AT is a direct function of the volume of atrial tissue ablated in the patients with atrial fibrillation (AF. Thus, the incidence of AT is highest in persistent AF patients undergoing stepwise ablation using the strategic combination of pulmonary vein isolation, electrogram based ablation and left atrial linear ablation. Using deductive mapping strategy, AT can be divided into three clinical categories viz. the macroreentry, the focal and the newly described localized reentry all of which are amenable to catheter ablation with success rate of 95%. Perimitral, roof dependent and cavotricuspid isthmus dependent AT involve large reentrant circuits which can be successfully ablated at the left mitral isthmus, left atrial roof and tricuspid isthmus respectively. Complete bidirectional block across the sites of linear ablation is a necessary endpoint. Focal and localized reentrant AT commonly originate from but are not limited to the septum, posteroinferior left atrium, venous ostia, base of the left atrial appendage and left mitral isthmus and they respond quickly to focal ablation. AT not only represents ablation-induced proarrhythmia but also forms a bridge between AF and sinus rhythm in longstanding AF patients treated successfully with catheter ablation.

  2. ANTIARRHYTMIC EFFICACY OF SOTALOL IN PATIENTS WITH TACHY-BRADY SYNDROME HAVING ATRIAL PACEMAKER WITH DIFFERENT ATRIAL ELECTRODE POSITION

    Directory of Open Access Journals (Sweden)

    T. N. Novikova

    2009-01-01

    Full Text Available Aim. To evaluate efficacy of the combined therapy (sotalol and constant electric cardiostimulation in AAI regimen at two atrial electrode position: in low back part of interatrial septum (IAS and in right atrial auricle (RAA.Material and methods. 20 patients with tachy-brady syndrome were examined. They were randomized in 2 groups depending on atrial electrode position. Sotalol (160 mg daily was prescribed to all patients in a month after implantation of constant atrial pacemaker (CAP. A number of atrial fibrillation paroxysms (AFP was evaluated initially, in a month after CAP implantation and in a month after start of sotalol therapy.Results. Significant AFP reduction was observed in IAS stimulation, unlike RAA stimulation. Sotalol addition had essential significance in the termination or reduction of AFP. Sotalol effect did not depend on atrial electrode position.Conclusion. Sotalol usage together with constant electric cardiostimulation significantly reduces AFP irrespectively of atrial electrode position. 

  3. Pitx2 modulates a Tbx5-dependent gene regulatory network to maintain atrial rhythm

    Science.gov (United States)

    Nadadur, Rangarajan D.; Broman, Michael T.; Boukens, Bastiaan; Mazurek, Stefan R.; Yang, Xinan; van den Boogaard, Malou; Bekeny, Jenna; Gadek, Margaret; Ward, Tarsha; Zhang, Min; Qiao, Yun; Martin, James F.; Seidman, Christine E.; Seidman, Jon; Christoffels, Vincent; Efimov, Igor R.; McNally, Elizabeth M.; Weber, Christopher R.; Moskowitz, Ivan P.

    2017-01-01

    Cardiac rhythm is extremely robust, generating 2 billion contraction cycles during the average human life span. Transcriptional control of cardiac rhythm is poorly understood. We found that removal of the transcription factor gene Tbx5 from the adult mouse caused primary spontaneous and sustained atrial fibrillation (AF). Atrial cardiomyocytes from the Tbx5-mutant mice exhibited action potential abnormalities, including spontaneous depolarizations, which were rescued by chelating free calcium. We identified a multitiered transcriptional network that linked seven previously defined AF risk loci: TBX5 directly activated PITX2, and TBX5 and PITX2 antagonistically regulated membrane effector genes Scn5a, Gja1, Ryr2, Dsp, and Atp2a2. In addition, reduced Tbx5 dose by adult-specific haploinsufficiency caused decreased target gene expression, myocardial automaticity, and AF inducibility, which were all rescued by Pitx2 haploinsufficiency in mice. These results defined a transcriptional architecture for atrial rhythm control organized as an incoherent feed-forward loop, driven by TBX5 and modulated by PITX2. TBX5/PITX2 interplay provides tight control of atrial rhythm effector gene expression, and perturbation of the co-regulated network caused AF susceptibility. This work provides a model for the molecular mechanisms underpinning the genetic implication of multiple AF genome-wide association studies loci and will contribute to future efforts to stratify patients for AF risk by genotype. PMID:27582060

  4. Pitx2 modulates a Tbx5-dependent gene regulatory network to maintain atrial rhythm.

    Science.gov (United States)

    Nadadur, Rangarajan D; Broman, Michael T; Boukens, Bastiaan; Mazurek, Stefan R; Yang, Xinan; van den Boogaard, Malou; Bekeny, Jenna; Gadek, Margaret; Ward, Tarsha; Zhang, Min; Qiao, Yun; Martin, James F; Seidman, Christine E; Seidman, Jon; Christoffels, Vincent; Efimov, Igor R; McNally, Elizabeth M; Weber, Christopher R; Moskowitz, Ivan P

    2016-08-31

    Cardiac rhythm is extremely robust, generating 2 billion contraction cycles during the average human life span. Transcriptional control of cardiac rhythm is poorly understood. We found that removal of the transcription factor gene Tbx5 from the adult mouse caused primary spontaneous and sustained atrial fibrillation (AF). Atrial cardiomyocytes from the Tbx5-mutant mice exhibited action potential abnormalities, including spontaneous depolarizations, which were rescued by chelating free calcium. We identified a multitiered transcriptional network that linked seven previously defined AF risk loci: TBX5 directly activated PITX2, and TBX5 and PITX2 antagonistically regulated membrane effector genes Scn5a, Gja1, Ryr2, Dsp, and Atp2a2 In addition, reduced Tbx5 dose by adult-specific haploinsufficiency caused decreased target gene expression, myocardial automaticity, and AF inducibility, which were all rescued by Pitx2 haploinsufficiency in mice. These results defined a transcriptional architecture for atrial rhythm control organized as an incoherent feed-forward loop, driven by TBX5 and modulated by PITX2. TBX5/PITX2 interplay provides tight control of atrial rhythm effector gene expression, and perturbation of the co-regulated network caused AF susceptibility. This work provides a model for the molecular mechanisms underpinning the genetic implication of multiple AF genome-wide association studies loci and will contribute to future efforts to stratify patients for AF risk by genotype.

  5. Right juxtaposition of the atrial appendages.

    Science.gov (United States)

    Mathew, R; Replogle, R; Thilenius, O G; Arcilla, R A

    1975-04-01

    We present an infant with right-sided juxtaposition of atrial appendages who had open heart surgery for ventricular septal defect and patent ductus arteriosus. Of 12 cases thus far reported, ventricular d-loop was observed in nine, and normal position of great vessels in four. Contrary to previous views, this condition may not be accompanied by severe conotruncal anomalies.

  6. Hypercoagulability promotes atrial fibrosis and fibrillation

    NARCIS (Netherlands)

    Spronk, Henri M.H.; De Jong, Anne-Margreet; De Boer, Hetty C.; Maas, Alexander; Verheule, Sander; Rienstra, Michiel; Kamphuisen, Pieter W.; Ten Cate, Hugo; Crijns, Harry J.; Van Gelder, Isabelle; Van Zonneveld, Anton Jan; Schotten, Ullrich

    2014-01-01

    Background: It is well known that atrial fibrillation (AF) induces a hypercoagulable state, which significantly increases stroke risk in patients with AF contributing to morbidity and mortality in these patients. Active coagulation factors can also provoke diverse cellular responses through stimulat

  7. Primary care aspects of atrial fibrillation

    NARCIS (Netherlands)

    Meijler, F.L.; Tweel, I. van der

    1985-01-01

    A better understanding of the pathophysiologic mechanisms that determine the random pattem of ventricular rhythm may assist the primary care physician in treating and guiding atrial fibrillation patients. These mechanisms also form the basis for our understanding of drug action and effect on ventric

  8. Spontaneous conversion of first onset atrial fibrillation

    DEFF Research Database (Denmark)

    Lindberg, Søren Østergaard; Hansen, Sidsel; Nielsen, Tonny

    2011-01-01

    Background  We studied all patients admitted to hospital with first onset atrial fibrillation (AF) to determine the probability of spontaneous conversion to sinus rhythm and to identify factors predictive of such a conversion. Methods and Results  We retrospectively reviewed charts of 438...

  9. Attitudes Towards Catheter Ablation for Atrial Fibrillation

    DEFF Research Database (Denmark)

    Vadmann, Henrik; Pedersen, Susanne S; Nielsen, Jens Cosedis;

    2015-01-01

    BACKGROUND: Catheter ablation for atrial fibrillation (AF) is an important but expensive procedure that is the subject of some debate. Physicians´ attitudes towards catheter ablation may influence promotion and patient acceptance. This is the first study to examine the attitudes of Danish...

  10. Genetic aspects of lone atrial fibrillation

    DEFF Research Database (Denmark)

    Andreasen, Laura; Nielsen, Jonas B; Olesen, Morten S

    2015-01-01

    Atrial fibrillation (AF) is the most common cardiac arrhythmia. A subgroup of patients presents with AF without traditional risk factors and is diagnosed before the age of 60 years. Such patients are commonly referred as having "lone AF" and comprise 10-20% of all cases. A number of studies have...

  11. Nonpenetrating right atrial and pericardial trauma.

    Science.gov (United States)

    Grande, Antonino M; Rinaldi, Mauro; Pasquino, Stefano; Dore, Roberto; Viganò, Mario

    2003-09-01

    Nonpenetrating chest trauma can cause cardiac rupture. Ventricles are affected more frequently than atria. Survival is rare and depends upon prompt diagnosis and immediate surgical intervention. We report the case of a 42-year-old man involved in a car accident with consequent right atrial rupture and pericardial tearing.

  12. Genetic Risk Prediction of Atrial Fibrillation

    NARCIS (Netherlands)

    Lubitz, Steven A; Yin, Xiaoyan; Lin, Henry; Kolek, Matthew; Smith, J Gustav; Trompet, Stella; Rienstra, Michiel; Rost, Natalia S; Teixeira, Pedro; Almgren, Peter; Anderson, Christopher D; Chen, Lin Y; Engström, Gunnar; Ford, Ian; Furie, Karen L; Guo, Xiuqing; Larson, Martin G; Lunetta, Kathryn; Macfarlane, Peter W; Psaty, Bruce M; Soliman, Elsayed Z; Sotoodehnia, Nona; Stott, David J; Taylor, Kent D; Weng, Lu-Chen; Yao, Jie; Geelhoed, Bastiaan; Verweij, Niek; Siland, Joylene E; Kathiresan, Sekar; Roselli, Carolina; Roden, Dan M; van der Harst, Pim; Darbar, Dawood; Jukema, J Wouter; Melander, Olle; Rosand, Jonathan; Rotter, Jerome I; Heckbert, Susan R; Ellinor, Patrick T; Alonso, Alvaro; Benjamin, Emelia J

    2016-01-01

    BACKGROUND: -Atrial fibrillation (AF) has a substantial genetic basis. Identification of individuals at greatest AF risk could minimize the incidence of cardioembolic stroke. METHODS: -To determine whether genetic data can stratify risk for development of AF, we examined associations between AF gene

  13. Imaging in percutaneous ablation for atrial fibrillation

    NARCIS (Netherlands)

    R. Maksimović (Ružica); T. Dill (Thorsten); A.D. Ristić (Arsen); P.M. Seferovic (Petar)

    2006-01-01

    textabstractPercutaneous ablation for electrical disconnection of the arrhythmogenic foci using various forms of energy has become a well-established technique for treating atrial fibrillation (AF). Success rate in preventing recurrence of AF episodes is high although associated with a significant

  14. Endometrial Adenocarcinoma with Concomitant Left Atrial Myxoma

    Directory of Open Access Journals (Sweden)

    Lisa N. Abaid

    2009-08-01

    Full Text Available Background: Atrial myxomas are the most common primary heart tumors and predominantly considered to be benign lesions. Case Study: We report a case involving a 77-year-old woman who presented with a pelvic mass. She was found to have a primary endometrial cancer and primary lung cancer with concomitant metastatic adrenal gland and mesenteric lesions. Her prior medical history also included an untreated 4.0 × 2.0-cm left atrial myxoma which was identified on CT scan during the workup of her pelvic mass. Results: A clinical decision was made to proceed with surgery for the pelvic mass with a subsequent recommendation for left atrial mass resection. Currently, the patient is scheduled to begin chemotherapy for primary lung cancer. Conclusion: The reported incidence of uterine cancer and a concurrent atrial myxoma is very rare. Consequently, the manner and timing in which treatment should be provided is imprecise. In the present case, the risk for cardiac complications was high, but given the presence of a partial bowel obstruction and the need to diagnose the primary site of her metastatic malignancy, the decision was made to proceed with exploratory abdominal surgery.

  15. Atrial fibrillation in rats induced by rapid transesophageal atrial pacing during brief episodes of asphyxia: a new in vivo model.

    Science.gov (United States)

    Haugan, Ketil; Lam, Henrik Rye; Knudsen, Carsten Boye; Petersen, Jørgen Søberg

    2004-07-01

    Non-pharmacological in vivo models of atrial fibrillation (AF) have been developed in large animals only. We aimed to develop and characterize a new small animal non-pharmacological in vivo model of AF. AF was induced by transesophageal atrial burst pacing during 35 seconds periods of asphyxia in anesthetized male Sprague-Dawley rats. AF was reproducibly induced in 81% of the rats. The presence of AF was associated with an increased heart rate, and a decreased blood pressure. Treatment with amiodarone, D,L-sotalol, flecainide, and propranolol all reduced duration of AF, whereas verapamil treatment was associated with a marked profibrillatory effect. Increasing gap junction intracellular communication using the antiarrhythmic peptide analogue AAP10 did not affect AF duration. Basal plasma level of epinephrine and norepinephrine were increased 5- to 20-fold relative to values reported by others, but unchanged following 35 seconds of asphyxia. The results from our study demonstrate that the rat model shares several clinical key characteristics with human AF: (1) hemodynamic response to AF; (2) increased autonomic tone; (3) antiarrhythmic effects of clinically used drugs; (4) profibrillatory effect of verapamil. Relative to existing models of AF in larger animals, this model offers rapid, predictive, and inexpensive testing of antiarrhythmic/profibrillatory effects of new drugs.

  16. Dual chamber pacemaker in the treatment of paroxysmal atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Rađen Goran

    2005-01-01

    Full Text Available Background. Atrial fibrillation is the most frequent cardiac dysrhythmia. The aim of this study was to show the role and the efficacy of a dual chamber pacemaker with the algorithm of atrial dynamic overdrive, in the suppression of paroxysmal atrial fibrillation. Case report. A woman with a classical bradycardia-tachycardia syndrome, and frequent attacks of atrial fibrillation, underwent the implantation of a single chamber permanent pacemaker (VVI. Pacemaker successfully treated the episodes of symptomatic bradycardia, but the patient had frequent attacks of atrial fibrillation, despite the use of different antiarrhythmic drugs, which she did not tolerate well. The decision was made to reimplant a permanent dual chamber pacemaker with the algorithm of atrial dynamic overdrive. The pacemaker was programmed to the basic rate of 75/min, while rate at rest was 55/min. In addition, sotalol was administered. After three months, the patient became asymptomatic with only 4 short − term episodes of atrial fibrillation, and a high level of atrial pacing (99%. Conclusion. In selected patients with bradycardia−tachycardia syndrome, atrial-based pacing seemed to be very effective in reducing the incidence of paroxysmal atrial fibrillation.

  17. Assessment of the dynamics of atrial signals and local atrial period series during atrial fibrillation: effects of isoproterenol administration

    Directory of Open Access Journals (Sweden)

    Mantica Massimo

    2004-10-01

    Full Text Available Abstract Background The autonomic nervous system (ANS plays an important role in the genesis and maintenance of atrial fibrillation (AF, but quantification of its electrophysiologic effects is extremely complex and difficult. Aim of the study was to evaluate the capability of linear and non-linear indexes to capture the fine changing dynamics of atrial signals and local atrial period (LAP series during adrenergic activation induced by isoproterenol (a sympathomimetic drug infusion. Methods Nine patients with paroxysmal or persistent AF (aged 60 ± 6 underwent electrophysiological study in which isoproterenol was administered to patients. Atrial electrograms were acquired during i sinus rhythm (SR; ii sinus rhythm during isoproterenol (SRISO administration; iii atrial fibrillation (AF and iv atrial fibrillation during isoproterenol (AFISO administration. The level of organization between two electrograms was assessed by the synchronization index (S, whereas the degree of recurrence of a pattern in a signal was defined by the regularity index (R. In addition, the level of predictability (LP and regularity of LAP series were computed. Results LAP series analysis shows a reduction of both LP and R index during isoproterenol infusion in SR and AF (RSR = 0.75 ± 0.07 RSRISO = 0.69 ± 0.10, p AF = 0.31 ± 0.08 RAFISO = 0.26 ± 0.09, p SR = 99.99 ± 0.001 LPSRISO = 99.97 ± 0.03, p AF = 69.46 ± 21.55 LPAFISO = 55 ± 24.75; p SR = 0.49 ± 0.08 RSRISO = 0.46 ± 0.09 p AF = 0.29 ± 0.09 RAFISO = 0.28 ± 0.08 n.s.. Conclusions The proposed parameters succeeded in discriminating the subtle changes due to isoproterenol infusion during both the rhythms especially when considering LAP series analysis. The reduced value of analyzed parameters after isoproterenol administration could reflect an important pro-arrhythmic influence of adrenergic activation on favoring maintenance of AF.

  18. Endurance sport practice as a risk factor for atrial fibrillation and atrial flutter.

    Science.gov (United States)

    Mont, Lluís; Elosua, Roberto; Brugada, Josep

    2009-01-01

    Although the benefits of regular exercise in controlling cardiovascular risk factors have been extensively proven, little is known about the long-term cardiovascular effects of regular and extreme endurance sport practice, such as jogging, cycling, rowing, swimming, etc. Recent data from a small series suggest a relationship between regular, long-term endurance sport practice and atrial fibrillation (AF) and flutter. Reported case control studies included less than 300 athletes, with mean age between 40 and 50. Most series recruited only male patients, or more than 70% males, who had been involved in intense training for many years. Endurance sport practice increases between 2 and 10 times the probability of suffering AF, after adjusting for other risk factors. The possible mechanisms explaining the association remain speculative. Atrial ectopic beats, inflammatory changes, and atrial size have been suggested. Some of the published studies found that atrial size was larger in athletes than in controls, and this was a predictor for AF. It has also been shown that the left atrium may be enlarged in as many as 20% of competitive athletes. Other proposed mechanisms are increased vagal tone and bradycardia, affecting the atrial refractory period; however, this may facilitate rather than cause the arrhythmia. In summary, recent data suggest an association between endurance sport practice and atrial fibrillation and flutter. The underlying mechanism explaining this association is unclear, although structural atrial changes (dilatation and fibrosis) are probably present. Larger longitudinal studies and mechanistic studies are needed to further characterize the association to clarify whether a threshold limit for the intensity and duration of physical activity may prevent AF, without limiting the cardiovascular benefits of exercise.

  19. 78 FR 11207 - Clinical Study Designs for Surgical Ablation Devices for Treatment of Atrial Fibrillation...

    Science.gov (United States)

    2013-02-15

    ... Treatment of Atrial Fibrillation; Guidance for Industry and Food and Drug Administration Staff; Availability... Ablation Devices for Treatment of Atrial Fibrillation.'' This guidance provides FDA's recommendations on clinical trial designs for surgical ablation devices intended for the treatment of atrial...

  20. Protein analysis of atrial fibrosis via label-free proteomics in chronic atrial fibrillation patients with mitral valve disease.

    Directory of Open Access Journals (Sweden)

    Peide Zhang

    Full Text Available BACKGROUND: Atrial fibrosis, as a hallmark of atrial structure remodeling, plays an important role in maintenance of chronic atrial fibrillation, but interrelationship of atrial fibrosis and atrial fibrillation is uncertain. Label-free proteomics can implement high throughput screening for finding and analyzing pivotal proteins related to the disease.. Therefore, we used label-free proteomics to explore and analyze differentially proteins in chronic atrial fibrillation patients with mitral valve disease. METHODS: Left and right atrial appendages obtained from patients with mitral valve disease were both in chronic atrial fibrillation (CAF, AF≥6 months, n = 6 and in sinus rhythm (SR, n = 6. One part of the sample was used for histological analysis and fibrosis quantification; other part were analyzed by label-free proteomic combining liquid chromatography with mass spectrometry (LC-MS, we utilized bioinformatics analysis to identify differential proteins. RESULTS: Degree of atrial fibrosis was higher in CAF patients than that of SR patients. 223 differential proteins were detected between two groups. These proteins mainly had vital functions such as cell proliferation, stress response, focal adhesion apoptosis. We evaluated that serine/threonine protein kinase N2 (PKN2, dermatopontin (DP, S100 calcium binding protein B (S100B, protein tyrosine kinase 2 (PTK2 and discoidin domain receptor tyrosine kinase 2 (DDR2 played important roles in fibrotic process related to atrial fibrillation. CONCLUSION: The study presented differential proteins responsible for atrial fibrosis in chronic atrial fibrillation patients through label-free proteomic analysis. We assessed some vital proteins including their characters and roles. These findings may open up new realm for mechanism research of atrial fibrillation.

  1. Electropathological substrate of long-standing persistent atrial fibrillation in patients with structural heart disease: longitudinal dissociation.

    NARCIS (Netherlands)

    Allessie, M.A.; Groot, N.M. de; Houben, R.P.; Schotten, U.; Boersma, E.; Smeets, J.L.R.M.; Crijns, H.J.G.M.

    2010-01-01

    BACKGROUND: The electropathological substrate of persistent atrial fibrillation (AF) in humans is largely unknown. The aim of this study was to compare the spatiotemporal characteristics of the fibrillatory process in patients with normal sinus rhythm and long-standing persistent AF. METHODS AND RES

  2. Electropathological substrate of long-standing persistent atrial fibrillation in patients with structural heart disease longitudinal dissociation

    NARCIS (Netherlands)

    M.A. Allessie (Maurits); N.M.S. de Groot (Natasja); R.P.M. Houben (Richard); U. Schotten (Ulrich); H. Boersma (Eric); J.L. Smeets (Joep); H. Crijns (Harry)

    2010-01-01

    textabstractBackground-The electropathological substrate of persistent atrial fibrillation (AF) in humans is largely unknown. The aim of this study was to compare the spatiotemporal characteristics of the fibrillatory process in patients with normal sinus rhythm and long-standing persistent AF. Meth

  3. Early recurrences of atrial fibrillation after electrical cardioversion : A result of fibrillation-induced electrical remodeling of the atria?

    NARCIS (Netherlands)

    Tieleman, RG; Van Gelder, IC; Crijns, HJGM; De Kam, PJ; Van den Berg, MP; Haaksma, J; Van der Woude, HJ; Allessie, MA

    1998-01-01

    Objectives, We sought to investigate whether, in humans, the timing and incidence of a relapse of atrial fibrillation (AF) during the first month after cardioversion indicates the presence of electrical remodeling and whether this could be influenced by prevention of intracellular calcium overload d

  4. The renal effects of atrial natriuretic peptide in man are not attenuated by (+)-sulpiride.

    OpenAIRE

    1989-01-01

    1. Human alpha atrial natriuretic peptide (ANP) was infused intravenously for 1 h in eight healthy salt-replete men on two occasions, with and without pretreatment with (+)-sulpiride. 2. ANP increased sodium excretion and urine flow rate but did not alter blood pressure or plasma renin activity. 3. (+)-sulpiride had no significant effect on baseline creatinine clearance, sodium excretion or urine flow rate and did not alter the increases in these parameters with ANP. 4. It is unlikely that th...

  5. Genetic variation in the two-pore domain potassium channel, TASK-1, may contribute to an atrial substrate for arrhythmogenesis

    DEFF Research Database (Denmark)

    Liang, Bo; Soka, Magdalena; Christensen, Alex Horby;

    2013-01-01

    The two-pore domain potassium channel, K2P3.1 (TASK-1) modulates background conductance in isolated human atrial cardiomyocytes and has been proposed as a potential drug target for atrial fibrillation (AF). TASK-1 knockout mice have a predominantly ventricular phenotype however, and effects of TASK......-1 inactivation on atrial structure and function have yet to be demonstrated in vivo. The extent to which genetic variation in KCNK3, that encodes TASK-1, might be a determinant of susceptibility to AF is also unknown. To address these questions, we first evaluated the effects of transient knockdown...... diameter (p=0.01) when compared with control-injected embryos. We next performed genetic screening of KCNK3 in two independent AF cohorts (373 subjects) and identified three novel KCNK3 variants. Two of these variants, present in one proband with familial AF, were located at adjacent nucleotides...

  6. [Atrial fibrillation as consequence and cause of structural changes of atria].

    Science.gov (United States)

    Aparina, O P; Chikhireva, L N; Stukalova, O V; Mironova, N A; Kashtanova, S Iu; Ternovoĭ, S K; Golitsyn, S P

    2014-01-01

    Changes of atrial structure and function are the contributors of atrial fibrillation clinical course, complications and treatment effectiveness. Effects of inflammation and mechanical stretch on atrial structural remodeling leading to atrial fibrillation are reviewed in the article. Contemporary invasive and non-invasive methods of evaluation (including late gadolinium enhancement magnetic resonance imaging) of patients with atrial structural remodeling in atrial fibrillation are also described.

  7. Vernakalant hydrochloride for the rapid conversion of atrial fibrillation after cardiac surgery

    DEFF Research Database (Denmark)

    Kowey, Peter R; Dorian, Paul; Mitchell, L Brent

    2009-01-01

    Postoperative atrial arrhythmias are common and are associated with considerable morbidity. This study was designed to evaluate the efficacy and safety of vernakalant for the conversion of atrial fibrillation (AF) or atrial flutter (AFL) after cardiac surgery.......Postoperative atrial arrhythmias are common and are associated with considerable morbidity. This study was designed to evaluate the efficacy and safety of vernakalant for the conversion of atrial fibrillation (AF) or atrial flutter (AFL) after cardiac surgery....

  8. Dronedarone for atrial fibrillation: a new therapeutic agent

    Directory of Open Access Journals (Sweden)

    Pawan D Patel

    2009-08-01

    Full Text Available Pawan D Patel, Rohit Bhuriya, Dipal D Patel, Bhaskar L Arora, Param P Singh, Rohit R AroraDepartment of Cardiology, Chicago Medical School, Chicago, IL, USAAbstract: Atrial fibrillation is the most common of the serious cardiac rhythm disturbances and is responsible for substantial morbidity and mortality. Amiodarone is currently one of the most widely used and most effective antiarrhythmic agents for atrial fibrillation. But during chronic usage amiodarone can cause some serious extra cardiac adverse effects, including effects on the thyroid. Dronedarone is a newer therapeutic agent with a structural resemblance to amiodarone, with two molecular changes, and with a better side effect profile. Dronedarone is a multichannel blocker and, like amiodarone, possesses both a rhythm and a rate control property in atrial fibrillation. The US Food and Drug Administration approved dronedarone for atrial fibrillation on July 2, 2009. In this review, we discuss the role of dronedarone in atrial fibrillation.Keywords: dronedarone, amiodarone, atrial fibrillation

  9. Atrial infarction is a unique and often unrecognized clinical entity

    Directory of Open Access Journals (Sweden)

    Rosana G. G. Mendes

    1999-03-01

    Full Text Available A patient with heart failure and acute atrial fibrillation received the final diagnosis of atrial infarction associated with ventricular infarction based on clinical findings of ischemia in association with atrial fibrillation and heart failure (mechanisms probably involved: contractile dysfunction and loss of atrial contribution. Although a transesophageal echocardiography, which could refine the diagnosis of anatomic abnormalities, was not performed, all evidence led to the diagnosis of atrial involvement. Electrocardiographic findings were consistent with Liu's major criterion 3. Therapy with digitalis, quinidine and angiotensin-converting enzyme inhibitors was chosen, as the patient had acute pulmonary edema. The use of beta-blockers and verapamil was restricted. No other complications, such as thrombo-embolism or atrial rupture, were noted.

  10. Atrial Myxoma in a Patient with Hypertrophic Cardiomyopathy

    Science.gov (United States)

    Abdou, Mahmoud; Hayek, Salim; Williams, Byron R.

    2013-01-01

    Atrial myxoma is the most common primary cardiac tumor. Patients with atrial myxoma typically present with obstructive, embolic, or systemic symptoms; asymptomatic presentation is very rare. To our knowledge, isolated association of atrial myxoma with hypertrophic cardiomyopathy has been reported only once in the English-language medical literature. We report the case of an asymptomatic 71-year-old woman with known hypertrophic cardiomyopathy in whom a left atrial mass was incidentally identified on cardiac magnetic resonance images. After surgical excision of the mass and partial excision of the left atrial septum, histopathologic analysis confirmed the diagnosis of atrial myxoma. The patient was placed on preventive implantable cardioverter-defibrillator therapy and remained asymptomatic. The management of asymptomatic cardiac myxoma is a topic of debate, because no reports definitively favor either conservative or surgical measures. PMID:24082380

  11. Molecular and phenotypic description of the widespread root symbiont Acephala applanata gen. et sp. nov., formerly known as dark-septate endophyte type 1.

    Science.gov (United States)

    Grünig, Christoph R; Sieber, Thomas N

    2005-01-01

    Acephala applanata gen. et sp. nov. is described. A. applanata is a dark-septate endophyte (DSE) of conifer roots and belongs to the Phialocephala fortinii species complex. Several genetic markers, including isozymes, inter-simple-sequence-repeat (ISSR) fingerprints, single-copy restriction fragment length polymorphisms (RFLP) and sequences of the internal transcribed spacers (ITS), let us unambiguously separate isolates of A. applanata from isolates of P. fortinii s.l. and other dark-septate endophytes. Alleles at four RFLP loci and two fixed nucleotides in the ITS region were diagnostic for A. applanata. One of the fixed nucleotides resulted in the addition of an Afa I restriction site. PCR amplification with primers prITS4 and the newly developed primer PF-ITS_F (ACT CTG AAT GTT AGT GAT GTC TGA GT) and restriction digestion with Afa I yielded three fragments (203 bp, 117 bp, 56 bp) in A. applanata but only two (260 bp and 117 bp) in P. fortinii s.l. Population differentiation (GST) between A. applanata and other cryptic species of P fortinii was pronounced, and the index of association (IA) did not deviate significantly from zero, showing that recombination occurs or had occurred in A. applanata. Although isolates of A. applanata never were observed to sporulate, it can be distinguished morphologically from P fortinii s.l. by the scarcity of aerial mycelium, significantly slower growth and denser mycelium on cellophane overlaid on water agar. These phenotypic characteristics, combined with diagnostic RFLP alleles and/or PCR-RFLP of the ITS fragment with the fixed Afa I restriction site, unequivocally allow identification of A. applanata.

  12. Association of Atrial Fibrillation with Morphological and Electrophysiological Changes of the Atrial Myocardium.

    Science.gov (United States)

    Matějková, Adéla; Šteiner, Ivo

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. For long time it was considered as pure functional disorder, but in recent years, there were identified atrial locations, which are involved in the initiation and maintenance of this arrhythmia. These structural changes, so called remodelation, start at electric level and later they affect contractility and morphology. In this study we attempted to find a possible relation between morphological (scarring, amyloidosis, left atrial (LA) enlargement) and electrophysiological (ECG features) changes in patients with AF. We examined grossly and histologically 100 hearts of necropsy patients - 54 with a history of AF and 46 without AF. Premortem ECGs were evaluated. The patients with AF had significantly heavier heart, larger LA, more severely scarred myocardium of the LA and atrial septum, and more severe amyloidosis in both atria. Severity of amyloidosis was higher in LAs vs. right atria (RAs). Distribution of both fibrosis and amyloidosis was irregular. The most affected area was in the LA anterior wall. Patients with a history of AF and with most severe amyloidosis have more often abnormally long P waves. Finding of long P wave may contribute to diagnosis of a hitherto undisclosed atrial fibrillation.

  13. Cardiac ion channels and mechanisms for protection against atrial fibrillation

    DEFF Research Database (Denmark)

    Grunnet, Morten; Bentzen, Bo Hjorth; Sørensen, Ulrik S;

    2011-01-01

    Atrial fibrillation (AF) is recognised as the most common sustained cardiac arrhythmia in clinical practice. Ongoing drug development is aiming at obtaining atrial specific effects in order to prevent pro-arrhythmic, devastating ventricular effects. In principle, this is possible due to a different...... to the recent discovery that Ca(2+)-activated small conductance K(+) channels (SK channels) are important for the repolarisation of atrial action potentials. Finally, an overview of current pharmacological treatment of AF is included....

  14. Echocardiographic assessment and percutaneous closure of multiple atrial septal defects

    Directory of Open Access Journals (Sweden)

    Timperley Jonathan

    2004-07-01

    Full Text Available Abstract Atrial septal defect closure is now routinely performed using a percutaneous approach under echocardiographic guidance. Centrally located, secundum defects are ideal for device closure but there is considerable morphological variation in size and location of the defects. A small proportion of atrial septal defects may have multiple fenestrations and these are often considered unsuitable for device closure. We report three cases of multiple atrial septal defects successfully closed with two Amplatzer septal occluders.

  15. Juxtaposed atrial appendages: A curiosity with some clinical relevance

    Directory of Open Access Journals (Sweden)

    Anil Kumar Singhi

    2016-01-01

    Full Text Available If the atrial appendages lie adjacent to each other on same side of the great arteries, instead of encircling their roots, they are referred as juxtaposed. Right juxtaposition of atrial appendages is less common than left juxtaposition. The images demonstrate the classical radiological, echocardiographic, and surgical images of juxtaposed atrial appendages. Their clinical incidence, associations, and relevance during interventional and surgical procedures are discussed.

  16. STRATEGIES OF PROPHYLAXIS AND MANAGEMENT OF POSTOPERATIVE ATRIAL FIBRILLATION

    Directory of Open Access Journals (Sweden)

    Dembele, A.

    2016-07-01

    Full Text Available This article analyses different strategies of prophylaxis and management of postoperative atrial fibrillation in patients undergoing coronary artery bypass grafting (CABG at different periods after acute myocardial infarction (AMI. It examines the efficacy of early administration of beta-adrenergic blocking agents (metoprolol and amiodarone (in prophylactic doses in the diminution of the risk of postoperative atrial fibrillation in different groups of patients. The article also discerns the effectiveness of digoxin in the management of episodes of postoperative atrial fibrillation.

  17. Genetics of Atrial Fibrillation and Possible Implications for Ischemic Stroke

    OpenAIRE

    Robin Lemmens; Sylvia Hermans; Dieter Nuyens; Vincent Thijs

    2011-01-01

    Atrial fibrillation is the most common cardiac arrhythmia mainly caused by valvular, ischemic, hypertensive, and myopathic heart disease. Atrial fibrillation can occur in families suggesting a genetic background especially in younger subjects. Additionally recent studies have identified common genetic variants to be associated with atrial fibrillation in the general population. This cardiac arrhythmia has important public health implications because of its main complications: congestive heart...

  18. How Is Atrial Fibrillation Diagnosed?

    Science.gov (United States)

    ... body and the balance of your body's electrolytes. Electrolytes are minerals that help maintain fluid levels and acid-base balance in the body. ... National Institutes of Health Department of Health and Human Services USA.gov

  19. The Maze procedure: surgical therapy for refractory atrial fibrillation.

    Science.gov (United States)

    McCarthy, P M; Castle, L W; Trohman, R G; Simmons, T W; Maloney, J D; Klein, A L; White, R D; Cox, J L

    1993-01-01

    Although atrial fibrillation is well tolerated by most patients, in some patients the consequences may be severe. The Maze procedure is a new open-heart operation that creates a carefully designed maze of incisions in the atrial myocardium; this maze then acts as an electrical conduit to channel atrial impulses from the sinoatrial node to the atrioventricular node. The Maze procedure has been shown to restore sinus rhythm and atrial systole (thus reducing the risk of thromboembolism), improve hemodynamics, alleviate palpitations, and eliminate the need for antiarrhythmic and anticoagulant drugs. We describe our first patient to undergo this operation.

  20. Fibrosis in Atrial Fibrillation - Role of Reactive Species and MPO.

    Science.gov (United States)

    Friedrichs, Kai; Baldus, Stephan; Klinke, Anna

    2012-01-01

    Atrial fibrosis with enhanced turnover and deposition of matrix proteins leads to inhomogeneous atrial electrical conduction and gives rise to electrical reentry circuits resulting in atrial fibrillation. The multifactorial pathogenesis of atrial fibrosis involves resident cardiac cells as well as infiltrating leukocytes, both generating and sequestering matrix metalloproteinases (MMPs), a key enzyme family involved in fibrosis. A growing body of evidence points toward an important role of reactive oxygen species (ROS) in the release and activation of pro-MMPs and the stimulation of pro-fibrotic cascades. Myeloperoxidase (MPO), a bactericidal enzyme released from activated polymorphonuclear neutrophils (PMN) is not only associated with a variety of cardiovascular diseases, but has also been shown to be mechanistically linked to atrial fibrosis and fibrillation. MPO catalyzes the generation of reactive species like hypochlorous acid, which affect intracellular signaling cascades in various cells and advance activation of pro-MMPs and deposition of atrial collagen resulting in atrial arrhythmias. Thus, inflammatory mechanisms effectively promote atrial structural remodeling and importantly contribute to the initiation and perpetuation of atrial fibrillation.

  1. [Atrial fibrillation concomitant with valvular heart disease].

    Science.gov (United States)

    Ishii, Yosuke

    2013-01-01

    Patients with valvular heart disease frequently have atrial fibrillation(AF) due to elevated pressure and dilatation of the left and right atria and pulmonary veins. Guidelines for valvular heart disease and AF recommend that surgical treatment for the valvular heart disease should be performed concomitantly with AF surgery. The Full-Maze procedure has evolved into the gold standard of treatment for medically refractory AF. In addition to the pulmonary vein isolation, the right and left atrial incisions of the Full-Maze procedure are designed to block potential macroreentrant pathways. According to the mechanisms of AF with valvular heart disease, the Full-Maze procedure is more effective for the patients than the pulmonary vein isolation alone.

  2. Propofol effects on atrial fibrillation wavefront delays.

    Science.gov (United States)

    Cervigón, Raquel; Moreno, Javier; Millet, José; Pérez-Villacastín, Julián; Castells, Francisco

    2010-08-01

    Since the cardiac activity during atrial fibrillation (AF) may be influenced by autonomic modulations, in this study, a novel method to quantify the effects of the most common anesthetic agent (propofol) in AF ablation procedures is introduced. This study has two main objectives: first, to assess whether the sedation earlier to radio frequency ablation affects the arrhythmia itself, and second, to provide new information that contributes to a better understanding of the influence of the autonomic nervous system on AF. The methodology presented is based on the measurement of synchronization and delay indexes between two atrial activations at adjacent intracavitary electrodes. These parameters aim to estimate whether two activations at different sites may be caused by the same propagating wavefront, or otherwise, are the consequence of independent wavefronts. The results showed that the mentioned indexes have a different behavior at both atria: the right atrium becomes more synchronized with propofol administration, whereas the synchronization index decreases at the left atrium.

  3. Pathogenic Mechanisms of Atrial Fibrillation in Obesity

    Directory of Open Access Journals (Sweden)

    O. M. Drapkina

    2016-01-01

    Full Text Available Atrial fibrillation (AF is one of the most common arrhythmias. It reduces quality of life and its duration due to thromboembolic complications. Obesity contributes to the structural and electrical remodeling of atrial myocardium. This leads to occurrence of ectopic foci in the mouths of the pulmonary veins and the disruption of normal electrical conduction in the atria. Systemic inflammation, myocardial fibrosis, cardiomyocyte overload by Na+ and Ca2+ ions, accumulation in the cells of unoxidized metabolic products, imbalance of the autonomic regulation are considered as the main mechanisms of arrhythmogenic substrate formation. Hypertension, insulin resistance, and obstructive sleep apnea, associated with obesity, increase the risk of development and progression of the arrhythmia. Study of pathogenetic mechanisms of AF in obesity is necessary to develop new strategies for its prevention and the creation of more effective methods of treatment of these patients.

  4. [Atrial fibrillation ablation: application of nurse methodology].

    Science.gov (United States)

    Ramos-González-Serna, Amelia; Mateos-García, M Dolores

    2011-01-01

    Ablation of pulmonary veins for treatment of atrial fibrillation involves applying radiofrequency energy wave by a catheter that causes a circumferential lesion to achieve electrical isolation and voltage drop in the interior. It is mainly applied when there is resistance to treatment and recurrence of symptoms affecting the quality of life of patients. The nurse is an important part of the multidisciplinary team who care for patients who undergo this procedure. The provision of comprehensive nursing care should include nursing procedures prior to, during, and after treatment to ensure the careful and systematic quality required. The aims of this article are: to provide specialised knowledge on the procedure of atrial fibrillation ablation, to describe the preparation of the electrophysiology laboratory, analyse nursing care and develop a standardized care plan for patients on whom this procedure is performed using the NANDA (North American Nursing Association) taxonomy and NIC (Nursing Intervention Classification).

  5. Retrieval of embolized left atrial appendage devices.

    Science.gov (United States)

    Fahmy, Peter; Eng, Lim; Saw, Jacqueline

    2016-09-28

    Percutaneous left atrial appendage (LAA) closure is gaining interest as an alternative option for prevention of strokes in patients with Atrial Fibrillation (AF), especially for those with contraindications to anticoagulation. Complications from these procedures are well described in the medical literature. LAA closures may lead to pericardial effusion, device-associated thrombus, and device embolization. Understanding the reasons for embolization, strategies to avoid embolization, and the techniques for retrieval of LAA devices (ACP/AMULET and WATCHMAN) should be appreciated by endovascular implanters. We describe two cases of LAA device embolization that were both successfully retrieved percutaneously and other percutaneous techniques to safely retrieve embolized LAA devices. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  6. Atrial fibrillation in obstructive sleep apnea

    OpenAIRE

    Goyal, Sandeep K; Sharma, Abhishek

    2013-01-01

    Atrial fibrillation (AF) is a common arrhythmia with rising incidence. Obstructive sleep apnea (OSA) is prevalent among patients with AF. This observation has prompted significant research in understanding the relationship between OSA and AF. Multiple studies support a role of OSA in the initiation and progression of AF. This association has been independent of obesity, body mass index and hypertension. Instability of autonomic tone and wide swings in intrathoracic pressure are seen in OSA. T...

  7. Acute atrial fibrillation during dengue hemorrhagic fever

    Directory of Open Access Journals (Sweden)

    Veloso Henrique Horta

    2003-01-01

    Full Text Available Dengue fever is a viral infection transmitted by the mosquito, Aedes aegypti. Cardiac rhythm disorders, such as atrioventricular blocks and ventricular ectopic beats, appear during infection and are attributed to viral myocarditis. However, supraventricular arrhythmias have not been reported. We present a case of acute atrial fibrillation, with a rapid ventricular rate, successfully treated with intravenous amiodarone, in a 62-year-old man with dengue hemorrhagic fever, who had no structural heart disease.

  8. Atrial Fibrillation During an Exploration Class Mission

    Science.gov (United States)

    Lipset, Mark A.; Lemery, Jay; Polk, J. D.; Hamilton, Douglas R.

    2010-01-01

    Background: A long-duration exploration class mission is fraught with numerous medical contingency plans. Herein, we explore the challenges of symptomatic atrial fibrillation (AF) occurring during an exploration class mission. The actions and resources required to ameliorate the situation, including the availability of appropriate pharmaceuticals, monitoring devices, treatment modalities, and communication protocols will be investigated. Challenges of Atrial Fibrillation during an Exploration Mission: Numerous etiologies are responsible for the initiation of AF. On Earth, we have the time and medical resources to evaluate and determine the causative situation for most cases of AF and initiate therapy accordingly. During a long-duration exploration class mission resources will be severely restricted. How is one to determine if new onset AF is due to recent myocardial infarction, pulmonary embolism, fluid overload, thyrotoxicosis, cardiac structural abnormalities, or CO poisoning? Which pharmaceutical therapy should be initiated and what potential side effects can be expected? Should anti-coagulation therapy be initiated? How would one monitor the therapeutic treatment of AF in microgravity? What training would medical officers require, and which communication strategies should be developed to enable the best, safest therapeutic options for treatment of AF during a long-duration exploration class mission? Summary: These questions will be investigated with expert opinion on disease elucidation, efficient pharmacology, therapeutic monitoring, telecommunication strategies, and mission cost parameters with emphasis on atrial fibrillation being just one illustration of the tremendous challenges that face a long-duration exploration mission. The limited crew training time, medical hardware, and drugs manifested to deal with such an event predicate that aggressive primary and secondary prevention strategies be developed to protect a multibillion-dollar asset like the

  9. Atrial Substrate Modification in Atrial Fibrillation: Targeting GP or CFAE? Evidence from Meta-Analysis of Clinical Trials

    OpenAIRE

    Qin, Mu; Liu, Xu; Wu, Shao-Hui; Zhang, Xiao-dong

    2016-01-01

    Several clinically relevant outcomes post atrial substrate modification in patients with atrial fibrillation (AF) have not been systematically analyzed among published studies on adjunctive cardiac ganglionated plexi (GP) or complex fractionated atrial electograms (CFAE) ablation vs. pulmonary vein isolation (PVI) alone. Out of 176 reports identified, the present meta-analysis included 14 randomized and non-randomized controlled trials (1613 patients) meeting inclusion criteria. Addition of G...

  10. [Relationship between atrial fibroblast proliferation/fibrosis and atrial fibrillation in patients with rheumatic heart disease].

    Science.gov (United States)

    Lin, Ya-Zhou; Cai, Jin-Ming; Chen, Lin; Yang, Zhi-Ping; Zhang, Jian-Cheng; Wu, Wei; Ke, Dan; Xu, Chun-Xuan

    2009-09-01

    To investigate the association between gene expressions of basic fibroblast growth factor (bFGF), smooth muscle alpha-actin (alpha-SMA) and proliferating cell nuclear antigen (PCNA) and atrial fibrosis in patients with atrial fibrillation (AF). The right atrial tissue samples were taken from 75 patients with rheumatic heart disease underwent heart valve replacement surgery (34 patients with sinus rhythm, 11 patients with paroxysmal AF and 30 patients with persistent AF) and stained with picrosirius red for quantitative analysis of collagen accumulation. The mRNA and protein levels of bFGF, alpha-SMA and PCNA were detected by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemical technique, respectively. The percent volume fraction of collagen (CVF) was the highest in persistent AF group and the lowest in the sinus rhythm group (all P fibrosis by promoting fibroblast proliferation in AF patients.

  11. The mechanisms of atrial fibrillation in hyperthyroidism

    Directory of Open Access Journals (Sweden)

    Bielecka-Dabrowa Agata

    2009-04-01

    Full Text Available Abstract Atrial fibrillation (AF is a complex condition with several possible contributing factors. The rapid and irregular heartbeat produced by AF increases the risk of blood clot formation inside the heart. These clots may eventually become dislodged, causing embolism, stroke and other disorders. AF occurs in up to 15% of patients with hyperthyroidism compared to 4% of people in the general population and is more common in men and in patients with triiodothyronine (T3 toxicosis. The incidence of AF increases with advancing age. Also, subclinical hyperthyroidism is a risk factor associated with a 3-fold increase in development of AF. Thyrotoxicosis exerts marked influences on electrical impulse generation (chronotropic effect and conduction (dromotropic effect. Several potential mechanisms could be invoked for the effect of thyroid hormones on AF risk, including elevation of left atrial pressure secondary to increased left ventricular mass and impaired ventricular relaxation, ischemia resulting from increased resting heart rate, and increased atrial eopic activity. Reentry has been postulated as one of the main mechanisms leading to AF. AF is more likely if effective refractory periods are short and conduction is slow. Hyperthyroidism is associated with shortening of action potential duration which may also contribute to AF.

  12. Atrial fibrillation associated with exogenous subclinical hyperthyroidism.

    Science.gov (United States)

    Patanè, Salvatore; Marte, Filippo

    2010-11-19

    Subclinical hyperthyroidism is an increasingly recognized entity that is defined as a normal serum free thyroxine and free triiodothyronine levels with a thyroid-stimulating hormone level suppressed below the normal range and usually undetectable. It has been reported that subclinical hyperthyroidism is not associated with coronary heart disease or mortality from cardiovascular causes but it is sufficient to induce arrhythmias including atrial fibrillation and atrial flutter. It has also been reported that increased factor X activity in patients with subclinical hyperthyroidism represents a potential hypercoagulable state. Moreover acute myocardial infarction has been reported during L-thyroxine substitution therapy. Far more common and relatively less studied is exogenous subclinical hyperthyroidism caused by L-thyroxine administration to thyroidectomized or hypothyroid patients or patients with simple or nodular goiter. We present a case of atrial fibrillation associated with exogenous subclinical hyperthyroidism, in a 72-year-old Italian woman. Also this case focuses attention on the importance of a correct evaluation of subclinical hyperthyroidism.

  13. Fibrilación atrial: nuevos conceptos

    Directory of Open Access Journals (Sweden)

    Luis Gutiérrez-Jaikel

    2004-06-01

    Full Text Available La fibrilación atrial es la arritmia más frecuente en la práctica clínica, se presenta tanto en pacientes con cardiopatía estructural de base principalmente hipertensiva, isquémica y valvular, como en pacientes sin trastorno cardiaco de fondo al avanzar la edad. Debido a la morbilidad asociada a esta, es vital su reconocimiento temprano y el manejo adecuado, con la finalidad de reducir la incidencia de complicaciones asociadas y mejorar la calidad de vida de quienes la padecen.Atrial fibrillation is the most frequent arrhythmia seen in clinical practice.It occurs most commonly on patients with hypertensive, isquemic and valvular heart disease as well as in patients without cardiac disease principally in elderly patients. Due to the morbidity rate associated with it (atrial fibrillation, early diagnosis and adequate treatment is necessary in order to reduce any associated complication and to improve the health related quality of life of patients who suffer from it.

  14. Dronedarone for the treatment of atrial fibrillation and atrial flutter: approval and efficacy

    Directory of Open Access Journals (Sweden)

    Deborah Wolbrette

    2010-06-01

    Full Text Available Deborah Wolbrette, Mario Gonzalez, Soraya Samii, Javier Banchs, Erica Penny-Peterson, Gerald NaccarelliPenn State Heart and Vascular Institute, Penn State Milton S Hershey Medical Center, Hershey, Pennsylvania, USAAbstract: Dronedarone, a new Class III antiarrhythmic agent, has now been approved by the US Food and Drug Administration for use in patients with atrial fibrillation or atrial flutter. Approval came in March 2009 due to the positive results of the ATHENA trial showing significant reductions in all-cause mortality and cardiovascular hospitalization with dronedarone use. A post hoc analysis of the ATHENA data also suggested a decrease in stroke risk with this agent. However, due to safety concerns in the heart failure population in the earlier ANDROMEDA trial, dronedarone is not recommended for patients with an ejection fraction <35% and recent decompensated heart failure. Dronedarone is an amiodarone analog with multichannel blocking electrophysiologic properties similar to those of amiodarone, but several structural differences. Dronedarone’s lack of the iodine moiety reduces its potential for thyroid and pulmonary toxicity. Preliminary data from the DIONYSOS trial, and an indirect meta-analysis comparing amiodarone with dronedarone, showed amiodarone to be more effective in maintaining sinus rhythm, while dronedarone was associated with fewer adverse effects resulting in early termination of the drug. Dronedarone is the first antiarrhythmic drug for the treatment of atrial fibrillation and atrial flutter shown to reduce cardiovascular hospitalizations. In patients with structural heart disease who have an ejection fraction >35% and no recent decompensated heart failure, dronedarone should be considered earlier than amiodarone in the treatment algorithm.Keywords: dronedarone, amiodarone, atrial fibrillation, atrial flutter

  15. Atrial and ventricular volume and function in persistent and permanent atrial fibrillation, a magnetic resonance imaging study

    DEFF Research Database (Denmark)

    Therkelsen, Susette Krohn; Groenning, Bjoern Aaris; Svendsen, Jesper Hastrup

    2005-01-01

    Left atrial size is independently related to cardiovascular morbidity and mortality, and atrial fibrillation (AF) is strongly associated with atrial size. Our aims were to report atrial and ventricular dimensions in patients with AF evaluated with magnetic resonance imaging (MRI), and to assess...... the inter-study reproducibility of the measurements. Nineteen healthy volunteers, 19 patients with permanent AF, and 58 patients with persistent AF had cardiac dimensions evaluated by 6-mm cinematographic breath-hold MRI scans using a 1.5 Tesla Siemens Vision Magnetom scanner with a phased array chest coil...

  16. Study on Effect of Compound Salvia Pellet in Preventing Atrial Fibrillation with Left Atrial Thrombosis

    Institute of Scientific and Technical Information of China (English)

    连耀植; 李玉光; 张汉灵; 张元春; 闫纯英; 林建才; 许瑞敏; 张钰; 郑宝群; 麦芒

    2004-01-01

    Atrialarrhythmia,fibrillation (AF) is a kind of common arrhythmia which, besides affecting cardiac function, has another serious outcome, that is, it is easy to form atrial thrombosis and induce thrombus/embolus, especially cerebral embolus. The incidence of left atrial thrombosis (LAT) could reach 25%—30%, the incidence of embolic complication per year could reach 2. 98%-6.30%, even 20% or more. To prevent thrombosis so as to lower the incidence of cerebral stroke and other embolic complications has been so far the focal point of AF treatment.

  17. Efficacy of atrial substrate modification based on dominant frequency of paroxysmal atrial fibrillation

    OpenAIRE

    KUMAGAI, Koji; Minami, Kentaro; Kutsuzawa, Daisuke; Oshima, Shigeru

    2016-01-01

    Background The endpoint of ablation procedures is suggested to be non-inducibility of paroxysmal atrial fibrillation (PAF). However, the prognosis of induced AF/atrial tachycardia (AT) after pulmonary vein isolation (PVI) in PAF patients remains unclear. Methods A total of 122 PAF patients were divided into the following 3 groups: Group 1, 79 without AF/AT induced after PVI; Group 2, 21 with AF/AT induced or sustained after PVI, and followed by a high-dominant frequency (DF) and continuous co...

  18. Rotigaptide (ZP123) improves atrial conduction slowing in chronic volume overload-induced dilated atria.

    Science.gov (United States)

    Haugan, Ketil; Miyamoto, Takuya; Takeishi, Yasuchika; Kubota, Isao; Nakayama, Jun; Shimojo, Hisashi; Hirose, Masamichi

    2006-07-01

    Chronic atrial dilation is associated with atrial conduction velocity slowing and an increased risk of developing atrial tachyarrhythmias. Rotigaptide (ZP123) is a selective gap junction modifier that increases cardiac gap junctional intercellular communication. We hypothesised that rotigaptide treatment would increase atrial conduction velocity and reduce the inducibility to atrial tachyarrhythmias in a model of chronic volume overload induced chronic atrial dilatation characterized by atrial conduction velocity slowing. Chronic volume overload was created in Japanese white rabbits by arterio-venous shunt formation. Atrial conduction velocity and atrial tachyarrhythmias inducibility were examined in Langendorff-perfused chronic volume overload hearts (n=12) using high-resolution optical mapping before and after treatment with rotigaptide. Moreover, expression levels of atrial gap junction proteins (connexin40 and connexin43) were examined in chronic volume overload hearts (n=6) and compared to sham-operated controls (n=6). Rotigaptide treatment significantly increased atrial conduction velocity in chronic volume overload hearts, however, rotigaptide did not decrease susceptibility to the induction of atrial tachyarrhythmias. Protein expressions of Cx40 and Cx43 were decreased by 32% and 72% (P<0.01), respectively, in chromic volume overload atria compared to control. To conclude, rotigaptide increased atrial conduction velocity in a rabbit model of chromic volume overload induced atrial conduction velocity slowing. The demonstrated effect of rotigaptide on atrial conduction velocity did not prevent atrial tachyarrhythmias inducibility. Whether rotigaptide may possess antiarrhythmic efficacy in other models of atrial fibrillation remains to be determined.

  19. Extracavitary manifestation of primary effusion lymphoma as a right atrial mass.

    Science.gov (United States)

    Marak, Creticus P; Ponea, Ana M; Shim, Chang; Shaheen, Shagufta; Guddati, Achuta K

    2013-01-01

    Primary effusion lymphoma (PEL) is a subset of large B cell lymphomas and has been mostly associated with human immunodeficiency virus infection. Rare cases have been reported in organ transplant recipients and chronic hepatitis C patients. It typically presents as an effusion in the pleural and pericardial spaces but rarely disseminates. However, involvement of the gastrointestinal tract, lymph nodes and bone marrow has been reported. Diagnosis is based on characteristic clinical, histopathological and immunohistochemical features. We present a case with a right atrial mass which tested positive for human herpes virus 8 (HHV-8), CD20, CD30 and lambda light chains and negative for CD138, kappa light chain, PAX5, Epstein-Barr virus, latent membrane protein 1, CD2, CD3, CD8 and CD56. Bilateral pleural effusions and pericardial effusions were noted which tested positive for HHV-8, CD30 and CD45. The patient responded well to the R-EPOCH regimen with complete resolution of the effusions and a significant decrease in the size of the right atrial mass. This case report illustrates the atypical manifestation of PEL as a right atrial mass.

  20. Extracavitary Manifestation of Primary Effusion Lymphoma as a Right Atrial Mass

    Directory of Open Access Journals (Sweden)

    Creticus P. Marak

    2013-02-01

    Full Text Available Primary effusion lymphoma (PEL is a subset of large B cell lymphomas and has been mostly associated with human immunodeficiency virus infection. Rare cases have been reported in organ transplant recipients and chronic hepatitis C patients. It typically presents as an effusion in the pleural and pericardial spaces but rarely disseminates. However, involvement of the gastrointestinal tract, lymph nodes and bone marrow has been reported. Diagnosis is based on characteristic clinical, histopathological and immunohistochemical features. We present a case with a right atrial mass which tested positive for human herpes virus 8 (HHV-8, CD20, CD30 and lambda light chains and negative for CD138, kappa light chain, PAX5, Epstein-Barr virus, latent membrane protein 1, CD2, CD3, CD8 and CD56. Bilateral pleural effusions and pericardial effusions were noted which tested positive for HHV-8, CD30 and CD45. The patient responded well to the R-EPOCH regimen with complete resolution of the effusions and a significant decrease in the size of the right atrial mass. This case report illustrates the atypical manifestation of PEL as a right atrial mass.

  1. Microcanonical processing methodology for ECG and intracardial potential: application to atrial fibrillation

    CERN Document Server

    Pont, Oriol; Yahia, Hussein; Derval, Nicolas; Hocini, Mélèze

    2012-01-01

    Cardiac diseases are the principal cause of human morbidity and mortality in the western world. The electric potential of the heart is a highly complex signal emerging as a result of nontrivial flow conduction, hierarchical structuring and multiple regulation mechanisms. Its proper accurate analysis becomes of crucial importance in order to detect and treat arrhythmias or other abnormal dynamics that could lead to life-threatening conditions. To achieve this, advanced nonlinear processing methods are needed: one example here is the case of recent advances in the Microcanonical Multiscale Formalism. The aim of the present paper is to recapitulate those advances and extend the analyses performed, specially looking at the case of atrial fibrillation. We show that both ECG and intracardial potential signals can be described in a model-free way as a fast dynamics combined with a slow dynamics. Sharp differences in the key parameters of the fast dynamics appear in different regimes of transition between atrial fibr...

  2. Atrial Heterogeneity Generates Re-entrant Substrate during Atrial Fibrillation and Anti-arrhythmic Drug Action: Mechanistic Insights from Canine Atrial Models.

    Science.gov (United States)

    Varela, Marta; Colman, Michael A; Hancox, Jules C; Aslanidi, Oleg V

    2016-12-01

    Anti-arrhythmic drug therapy is a frontline treatment for atrial fibrillation (AF), but its success rates are highly variable. This is due to incomplete understanding of the mechanisms of action of specific drugs on the atrial substrate at different stages of AF progression. We aimed to elucidate the role of cellular, tissue and organ level atrial heterogeneities in the generation of a re-entrant substrate during AF progression, and their modulation by the acute action of selected anti-arrhythmic drugs. To explore the complex cell-to-organ mechanisms, a detailed biophysical models of the entire 3D canine atria was developed. The model incorporated atrial geometry and fibre orientation from high-resolution micro-computed tomography, region-specific atrial cell electrophysiology and the effects of progressive AF-induced remodelling. The actions of multi-channel class III anti-arrhythmic agents vernakalant and amiodarone were introduced in the model by inhibiting appropriate ionic channel currents according to experimentally reported concentration-response relationships. AF was initiated by applied ectopic pacing in the pulmonary veins, which led to the generation of localized sustained re-entrant waves (rotors), followed by progressive wave breakdown and rotor multiplication in both atria. The simulated AF scenarios were in agreement with observations in canine models and patients. The 3D atrial simulations revealed that a re-entrant substrate was typically provided by tissue regions of high heterogeneity of action potential duration (APD). Amiodarone increased atrial APD and reduced APD heterogeneity and was more effective in terminating AF than vernakalant, which increased both APD and APD dispersion. In summary, the initiation and sustenance of rotors in AF is linked to atrial APD heterogeneity and APD reduction due to progressive remodelling. Our results suggest that anti-arrhythmic strategies that increase atrial APD without increasing its dispersion are

  3. Prolonged and fractionated right atrial electrograms during sinus rhythm in patients with paroxysmal atrial fibrillation and sick sinus node syndrome.

    Science.gov (United States)

    Tanigawa, M; Fukatani, M; Konoe, A; Isomoto, S; Kadena, M; Hashiba, K

    1991-02-01

    Intraatrial catheter mapping of the right atrium was performed during sinus rhythm in 92 patients: Group I = 43 control patients without paroxysmal atrial fibrillation or sick sinus node syndrome; Group II = 31 patients with paroxysmal atrial fibrillation but without sick sinus node syndrome; and Group III = 18 patients with both paroxysmal atrial fibrillation and sick sinus node syndrome. Atrial electrograms were recorded at 12 sites in the right atrium. The duration and number of fragmented deflections of the atrial electrograms were quantitatively measured. The mean duration and number of fragmented deflections of the 516 atrial electrograms in Group I were 74 +/- 11 ms and 3.9 +/- 1.3, respectively. The criteria for an abnormal atrial electrogram were defined as a duration of greater than or equal to 100 ms or eight or more fragmented deflections, or both. Abnormal atrial electrograms were observed in 10 patients (23.3%) in Group I, 21 patients (67.7%) in Group II and 15 patients (83.3%) in Group III (Group II versus Group I, p less than 0.001; Group III versus Group I, p less than 0.001). The mean number of abnormal electrograms per patient with an abnormal electrogram was 1.3 +/- 0.7 in Group I, 2.5 +/- 1.9 in Group II and 3.5 +/- 2.5 in Group III (Group I versus Group II, p less than 0.01; Group II versus Group III, p less than 0.05). A prolonged and fractionated atrial electrogram characteristic of paroxysmal atrial fibrillation can be closely related to the vulnerability of the atrial muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Ethnic Differences in Atrial Fibrillation Identified Using Implanted Cardiac Devices

    NARCIS (Netherlands)

    Lau, Chu-Pak; Gbadebo, T. David; Connolly, Stuart J.; Van Gelder, Isabelle C.; Capucci, Alessandro; Gold, Michael R.; Israel, Carsten W.; Morillo, Carlos A.; Siu, Chung-Wah; Abe, Haruhiko; Carlson, Mark; Tse, Hung-Fat; Hohnloser, Stefan H.; Healey, Jeff S.

    2013-01-01

    Ethnic Difference in Atrial Fibrillation Incidence.Introduction: Atrial fibrillation (AF) is suggested to be less common among black and Asian individuals, which could reflect bias in symptom reporting and access to care. In the Asymptomatic AF and Stroke Evaluation in Pacemaker Patients and the AF

  5. Dronedarone in high-risk permanent atrial fibrillation

    DEFF Research Database (Denmark)

    Connolly, Stuart J; Camm, A John; Halperin, Jonathan L;

    2011-01-01

    Dronedarone restores sinus rhythm and reduces hospitalization or death in intermittent atrial fibrillation. It also lowers heart rate and blood pressure and has antiadrenergic and potential ventricular antiarrhythmic effects. We hypothesized that dronedarone would reduce major vascular events...... in high-risk permanent atrial fibrillation....

  6. Dynamics of Focal Fibrillation Waves during Persistent Atrial Fibrillation.

    Science.gov (United States)

    Lanters, Eva A H; Allessie, Maurits A; DE Groot, Natasja M S

    2016-04-01

    The incidence and appearance of focal fibrillation waves on the right and left atrial epicardial surface were visualized during 10 seconds of persistent atrial fibrillation in a 71-year-old woman with valvular heart disease. The frequent, nonrepetitive, widespread, and capricious distribution of focal waves suggests that transmural conduction of fibrillation waves is most likely the mechanism underlying focal fibrillation waves.

  7. Rising rates of hospital admissions for atrial fibrillation

    DEFF Research Database (Denmark)

    Friberg, Jens; Buch, Nina Pernille Gardshodn; Scharling, Henrik;

    2003-01-01

    Atrial fibrillation is a common arrhythmia associated with excess morbidity and mortality. We studied temporal changes in hospital admission rates for atrial fibrillation using data from a prospective population-based cohort study spanning 2 decades (the Copenhagen City Heart Study)....

  8. Atrial fibrillation: Is ablation the way of the future?

    Institute of Scientific and Technical Information of China (English)

    Brian Olshansky

    2004-01-01

    @@ This issue of the Journal of Geriatric Cardiology features a manuscript entitled "A three-pulmonary vein isolation approach to treat paroxysmal atrial fibrillation".Dr. Lexin Wang addresses an important issue, and is to be congratulated for taking a new look at an approach to ablate atrial fibrillation.

  9. KCNE3 R53H substitution in familial atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dai-fu; LIANG Bo; LIN Jie; LIU Ban; ZHOU Qin-shu; YANG Yi-qing

    2005-01-01

    @@ Atrial fibrillation (AF) is the most common cardiac arrhythmia with debilitating compli-cations of stroke. Multiple-wavelet re-entry and focal activation from pulmonary vein foci are two dominant electrophysiological theories of AF. Atrial electrical remodeling plays a role in the maintenance of AF. However, molecular mechanisms of the arrhythmia are still poorly understood.

  10. The immediate future for the medical treatment of atrial fibrillation

    DEFF Research Database (Denmark)

    Pedersen, Ole Dyg; Brendorp, Bente; Køber, Lars;

    2002-01-01

    Atrial fibrillation is the most commonly sustained cardiac arrhythmia and a common reason for mortality and morbidity. Atrial fibrillation causes disease for three reasons: i) the ventricular rate is often high, which leads to symptoms ranging from discomfort to life threatening heart failure; ii...

  11. Vascular disease and stroke risk in atrial fibrillation

    DEFF Research Database (Denmark)

    Olesen, Jonas Bjerring; Lip, Gregory Y.H.; Lane, Deirdre A

    2012-01-01

    Vascular disease (including myocardial infarction and peripheral artery disease) has been proposed as a less well-validated risk factor for stroke in patients with atrial fibrillation. We investigated whether vascular disease is an independent risk factor of stroke/thromboembolism in atrial...... fibrillation and whether adding vascular disease improves Congestive heart failure, Hypertension, Age 75 years, Diabetes, previous Stroke (CHADS(2)) risk stratification....

  12. Radiofrequency ablation as initial therapy in paroxysmal atrial fibrillation

    DEFF Research Database (Denmark)

    Cosedis Nielsen, Jens; Johannessen, Arne; Raatikainen, Pekka;

    2012-01-01

    There are limited data comparing radiofrequency catheter ablation with antiarrhythmic drug therapy as first-line treatment in patients with paroxysmal atrial fibrillation.......There are limited data comparing radiofrequency catheter ablation with antiarrhythmic drug therapy as first-line treatment in patients with paroxysmal atrial fibrillation....

  13. Monitoring the complexity of ventricular response in atrial fibrillation

    Directory of Open Access Journals (Sweden)

    H. Käsmacher

    2000-01-01

    Full Text Available Atrial fibrillation does not present a uniform extent of variability of the ventricular response exemplifying periodicities and more complex fluctuations, due to varying number and shape of atrial wavelets and aberrant conduction in the AV-junction. It was sought to categorise different degrees of complexity introducing an uncomplicated monitoring method for that objective.

  14. Atrial fibrillation and bleeding complication - risk factors and risk marker

    NARCIS (Netherlands)

    Breithardt, G.; Ravens, U.; Kirchhof, P.; van Gelder, I. C.

    2012-01-01

    The development of atrial fibrillation (AF) is closely linked to risk factors like hypertension and heart failure, diabetes mellitus, myocardial infarction and valvular heart disease. These factors partly overlap with those which determine the progression of atrial fibrillation and the incidence of

  15. Atrial Arrhythmias and Their Implications for Space Flight - Introduction

    Science.gov (United States)

    Polk, J. D.; Barr, Y. R.; Bauer, P.; Hamilton, D. R.; Kerstman, E.; Tarver, B.

    2010-01-01

    This panel will discuss the implications of atrial arrhythmias in astronauts from a variety of perspectives; including historical data, current practices, and future challenges for exploration class missions. The panelists will present case histories, outline the evolution of current NASA medical standards for atrial arrhythmias, discuss the use of predictive tools, and consider potential challenges for current and future missions.

  16. Sotalol for atrial tachycardias after surgery for congenital heart disease

    NARCIS (Netherlands)

    BeaufortKrol, GCM; BinkBoelkens, MTE

    1997-01-01

    Atrial tachycardias, in particular atrial flutter after surgery for congenital heart disease, is associated with a high mortality. Treatment with various antiarrhythmic drugs and/or antitachycardia pacemakers is not very successful. Sotalol, a Class III drug, has shown to be a promising drug in adul

  17. Pulmonary edema following transcatheter closure of atrial septal defect

    Directory of Open Access Journals (Sweden)

    Singhi Anil

    2010-01-01

    Full Text Available Pulmonary edema after device closure of atrial septal defect (ASD is a rare complication. We present illustrative images of a case of pulmonary edema after device closure of ASD in a 53 year old adult. Older patients undergoing ASD closure can benefit from their left atrial and left ventricular end diastolic pressures measurement before and after temporary balloon occlusion of ASD.

  18. Atrial rate and rhythm abnormalities in a patient with hyperkalemia.

    Science.gov (United States)

    Rosman, Jonathan; Thiagarajah, Prashan; Schweitzer, Paul; Rachko, Maurice; Hanon, Sam

    2009-05-15

    A 67 year old man presented with a serum potassium of 7.7 mEq/L and slow atrial flutter with variable A-V block and peaked T waves. Initial treatment for hyperkalemia was followed by an increase in the atrial flutter rate to 300 beats per minute. After hemodialysis the rhythm converted to sinus.

  19. Association between familial atrial fibrillation and risk of new-onset atrial fibrillation

    NARCIS (Netherlands)

    Lubitz, Steven A.; Yin, Xiaoyan; Fontes, Joao D.; Magnani, Jared W.; Rienstra, Michel; Pai, Manju; Villalon, Mark L.; Vasan, Ramachandran S.; Pencina, Michael J.; Levy, Daniel; Larson, Martin G.; Ellinor, Patrick T.; Benjamin, Emelia J.

    2010-01-01

    CONTEXT: Although the heritability of atrial fibrillation (AF) is established, the contribution of familial AF to predicting new-onset AF remains unknown. OBJECTIVE: To determine whether familial occurrence of AF is associated with new-onset AF beyond established risk factors. DESIGN, SETTING, AND

  20. Atrial metabolism and tissue perfusion as determinants of electrical and structural remodelling in atrial fibrillation.

    Science.gov (United States)

    Opacic, Dragan; van Bragt, Kelly A; Nasrallah, Hussein M; Schotten, Ulrich; Verheule, Sander

    2016-04-01

    Atrial fibrillation (AF) is the most common tachyarrhythmia in clinical practice. Over decades of research, a vast amount of knowledge has been gathered about the causes and consequences of AF related to cellular electrophysiology and features of the tissue structure that influence the propagation of fibrillation waves. Far less is known about the role of myocyte metabolism and tissue perfusion in the pathogenesis of AF. However, the rapid rates of electrical activity and contraction during AF must present an enormous challenge to the energy balance of atrial myocytes. This challenge can be met by scaling back energy demand and by increasing energy supply, and there are several indications that both phenomena occur as a result of AF. Still, there is ample evidence that these adaptations fall short of redressing this imbalance, which may represent a driving force for atrial electrical as well as structural remodelling. In addition, several 'metabolic diseases' such as diabetes, obesity, and abnormal thyroid function precipitate some well-known 'culprits' of the AF substrate such as myocyte hypertrophy and fibrosis, while some other AF risk factors, such as heart failure, affect atrial metabolism. This review provides an overview of metabolic and vascular alterations in AF and their involvement in its pathogenesis.

  1. Increased TRPM6 expression in atrial fibrillation patients contribute to atrial fibrosis.

    Science.gov (United States)

    Zhang, Yun-Jiao; Ma, Nan; Su, Feng; Liu, Hao; Mei, Ju

    2015-06-01

    Transient receptor potential (TRP) family plays important roles in cardiovascular system. We investigated the relationship between transient receptor potential channel subfamily M6 (TRPM6) and atrial fibrosis in rheumatic heart disease patients with atrial fibrillation (AF). The right atrial tissue samples were obtained from 64 patients with rheumatic heart diseases who underwent heart valve replacement surgery, and composed of 34 sinus rhythm (SR) patients and 30 AF patients. Hematoxylin and Eosin (HE) staining was used to observe cross-sectional area (CSA) of myocardial cell. Masson staining and measurement of connective tissue growth factor (CTGF), transforming growth factor beta 1 (TGF-β 1), and collagen type I/III (Collagen I/III) were performed to determine atrial fibrosis. The mRNA and protein levels of TRPM6 were detected by real-time quantitative polymerase chain reaction (RT-PCR) and western blotting, respectively. Marked increases were observed in CSA of myocardial cell and myocardial collagen volume fraction in AF group compared with the SR group (all Pfibrosis markers (CTGF, TGF-beta 1, Collagen I/III) in AF group increased significantly compared to the SR group (all Pfibrosis, and suggested that TRPM6 might be involved in AF development by promoting fibrogenesis. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Recurrent patterns of atrial depolarization during atrial fibrillation assessed by recurrence plot quantification.

    Science.gov (United States)

    Censi, F; Barbaro, V; Bartolini, P; Calcagnini, G; Michelucci, A; Gensini, G F; Cerutti, S

    2000-01-01

    The aim of this study was to determine the presence of organization of atrial activation processes during atrial fibrillation (AF) by assessing whether the activation sequences are wholly random or are governed by deterministic mechanisms. We performed both linear and nonlinear analyses based on the cross correlation function (CCF) and recurrence plot quantification (RPQ), respectively. Recurrence plots were quantified by three variables: percent recurrence (PR), percent determinism (PD), and entropy of recurrences (ER). We recorded bipolar intra-atrial electrograms in two atrial sites during chronic AF in 19 informed subjects, following two protocols. In one, both recording sites were in the right atrium; in the other protocol, one site was in the right atrium, the other one in the left atrium. We extracted 19 episodes of type I AF (Wells' classification). RPQ detected transient recurrent patterns in all the episodes, while CCF was significant only in ten episodes. Surrogate data analysis, based on a cross-phase randomization procedure, decreased PR, PD, and ER values. The detection of spatiotemporal recurrent patterns together with the surrogate data results indicate that during AF a certain degree of local organization exists, likely caused by deterministic mechanisms of activation.

  3. Association between familial atrial fibrillation and risk of new-onset atrial fibrillation

    NARCIS (Netherlands)

    Lubitz, Steven A.; Yin, Xiaoyan; Fontes, Joao D.; Magnani, Jared W.; Rienstra, Michel; Pai, Manju; Villalon, Mark L.; Vasan, Ramachandran S.; Pencina, Michael J.; Levy, Daniel; Larson, Martin G.; Ellinor, Patrick T.; Benjamin, Emelia J.

    2010-01-01

    CONTEXT: Although the heritability of atrial fibrillation (AF) is established, the contribution of familial AF to predicting new-onset AF remains unknown. OBJECTIVE: To determine whether familial occurrence of AF is associated with new-onset AF beyond established risk factors. DESIGN, SETTING, AND P

  4. Molecular mechanisms of early atrial remodeling by rapid atrial pacing in rabbits

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Objective: To establish a rabbit atrial fibrillation model with rapid atrial pacing (RAP) and investigate its ultrastructural changes and expressions of L-type calcium channel subunits and potassium channel Ky4.3. Methods: Thirty-six rabbits were performed electrical stimulation through bipolar endocardial led by surgical technique, 600 beat per min from 0 to 48 h. Atrial ultrastructure was observed by transmission electron microscope (TEM) after different pacing times. mRNA were measured by reverse transcription-polymerase chain reaction (RT-PCR). Results: Atrial ultrastructure had alteration after 3 hours' pacing, such as mitochondria vacuolization, myofilament lysis and glucogen aggregation. The mRNA of the Ca2+ channel β1 and α1 subunits began to decrease after pacing of 6 h, which were paralleled with the change of Kv4.3 mRNA. But the auxiliary subunit α2 were not affected. Conclusion: Ultrastructural changes and mRNA levels of L-type calcium channel subunits and potassium channel Kv4.3 are decreased after RAP, with a mechanism of transcriptional down-regulation of underlying ion channels due to calcium overloading after RAP.

  5. Does Myocardial Infarction Beget Atrial Fibrillation and Atrial Fibrillation Beget Myocardial Infarction?

    NARCIS (Netherlands)

    Vermond, Rob A.; Van Gelder, Isabelle C.; Crijns, Harry J.; Rienstra, Michiel

    2015-01-01

    Atrial fibrillation (AF) affects millions of people worldwide.(1) It is already known several decades that AF is not a benign condition, and it's associated with a 5-fold increased risk of stroke, 3-fold increased risk of heart failure, and doubling of risk of dementia and death.(2-4) Myocardial

  6. Atrial Arrhythmias in Astronauts. Summary of a NASA Summit

    Science.gov (United States)

    Barr, Yael; Watkins, Sharmila; Polk, J. D.

    2011-01-01

    This slide presentation reviews the findings of a panel of heart experts brought together to study if atrial arrhythmias more prevalent in astronauts, and potential risk factors that may predispose astronauts to atrial arrhythmias. The objective of the panel was to solicit expert opinion on screening, diagnosis, and treatment options, identify gaps in knowledge, and propose relevant research initiatives. While Atrial Arrhythmias occur in approximately the same percents in astronauts as in the general population, they seem to occur at younger ages in astronauts. Several reasons for this predisposition were given: gender, hypertension, endurance training, and triggering events. Potential Space Flight-Related Risk factors that may play a role in precipitating lone atrial fibrillation were reviewed. There appears to be no evidence that any variable of the space flight environment increases the likelihood of developing atrial arrhythmias during space flight.

  7. Genetics of Atrial Fibrillation and Possible Implications for Ischemic Stroke

    Directory of Open Access Journals (Sweden)

    Robin Lemmens

    2011-01-01

    Full Text Available Atrial fibrillation is the most common cardiac arrhythmia mainly caused by valvular, ischemic, hypertensive, and myopathic heart disease. Atrial fibrillation can occur in families suggesting a genetic background especially in younger subjects. Additionally recent studies have identified common genetic variants to be associated with atrial fibrillation in the general population. This cardiac arrhythmia has important public health implications because of its main complications: congestive heart failure and ischemic stroke. Since atrial fibrillation can result in ischemic stroke, one might assume that genetic determinants of this cardiac arrhythmia are also implicated in cerebrovascular disease. Ischemic stroke is a multifactorial, complex disease where multiple environmental and genetic factors interact. Whether genetic variants associated with a risk factor for ischemic stroke also increase the risk of a particular vascular endpoint still needs to be confirmed in many cases. Here we review the current knowledge on the genetic background of atrial fibrillation and the consequences for cerebrovascular disease.

  8. Importância da anatomia da circulação coronária atrial na operação de Cox para controle da fibrilação atrial The importance of atrial coronary circulation on Cox surgery for control atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Marcelo B. JATENE

    1999-01-01

    Full Text Available Com o advento de novas técnicas cirúrgicas para o tratamento das arritmias cardíacas, em especial da fibrilação atrial, como a cirurgia de Cox, o conhecimento das características e do trajeto das artérias coronárias atriais assumiu grande importância. O objetivo deste trabalho é o estudo desta circulação e a definição dos padrões de irrigação atrial. Para tanto, utilizamos 30 corações a fresco de indivíduos sem cardiopatia prévia, cujas artérias coronárias e ramos foram visibilizados através de injeção de resina vinílica corada com tinta laca preta, seguida de cuidadosa dissecção. Após avaliação macroscópica das peças, não foram encontrados padrões de irrigação uniforme dos átrios. Porém, a artéria do nó sinoatrial (ANSA, quando analisada isoladamente, revelou não apenas padrões de origem, como também padrões de trajeto. Foram descritos 7 padrões de origem e trajeto da ANSA, considerando-se pontos de referências da estrutura anatômica dos átrios. Os padrões descritos, diferente dos encontrados por outros autores, são de fácil interpretação e de aplicabilidade direta em técnicas cirúrgicas que abordam os átrios.Since the appearance of new surgical techniques such as Cox surgery employed for the treatment of cardiac arrhythmia, especially for atrial fibrillation, the knowledge of coronary artery characteristics and courses has been of increasing importance. The aim of this study was the analysis of this circulation and definition of atrial irrigation patterns. Hence, the coronary arteries of 30 normal human hearts were injected with colored resin and carefully dissected. After macroscopic evaluation of the hearts, no atrial irrigation patterns were found. However, when only the sinus atrial node was analyzed, it showed origin patterns as well as course patterns. Seven origin and route patterns of this artery are described, considering the anatomical structure of the atria as reference

  9. Atrial Strain and Strain Rate: A Novel Method for the Evaluation of Atrial Stunning

    Science.gov (United States)

    Ozkan, Hakan; Binici, Suleyman; Tenekecioglu, Erhan; Ari, Hasan; Bozat, Tahsin

    2016-01-01

    Background Atrial fibrillation (AF) is the most common arrhythmia seen in adults. Atrial stunning is defined as the temporary mechanical dysfunction of the atrial appendage developing after AF has returned to sinus rhythm (SR). Objectives We aimed to evaluate atrial contractile functions by strain and strain rate in patients with AF, following pharmacological and electrical cardioversion and to compare it with conventional methods. Methods This study included 41 patients with persistent AF and 35 age-matched control cases with SR. All the AF patients included in the study had transthoracic and transesophageal echocardiography performed before and after. Septum (SEPsSR), left atrium (LAsSR) and right atrium peak systolic strain rate (RAsSR) were defined as the maximum negative value during atrial contraction and septum (SEPε), left atrium (LAε) and right atrium peak systolic strain (RAε) was defined as the percentage of change. Parameters of two groups were compared. Results In the AF group, 1st hour and 24th hour LAε, RAε, SEPε, LAsSR, RAsSR, SEPsSR found to be significantly lower than in the control group (LAε: 2.61%±0.13, 3.06%±0.19 vs 6.45%±0.27, p<0.0001; RAε: 4.03%±0.38, 4.50%±0.47 vs 10.12%±0.64, p<0.0001; SEPε: 3.0%±0.22, 3.19%±0.15 vs 6.23%±0.49, p<0.0001; LAsSR: 0.61±0.04s-1, 0.75±0.04s-1 vs 1.35±0.04s-1, p<0.0001; RAsSR: 1.13±0.06s-1, 1.23±0.07s-1 vs 2.10±0.08s- 1, p<0.0001; SEPsSR: 0.76±0.04s- 1, 0.78±0.04s- 1 vs 1.42±0.06 s- 1, p<0.0001). Conclusion Atrial strain and strain rate parameters are superior to conventional echocardiographic parameters for the evaluation of atrial stunning in AF cases where SR has been achieved. PMID:27627221

  10. Effect of renal sympathetic denervation on atrial substrate remodeling in ambulatory canines with prolonged atrial pacing.

    Directory of Open Access Journals (Sweden)

    Xule Wang

    Full Text Available We have previously demonstrated that catheter-based renal sympathetic denervation (RSD could suppress atrial fibrillation (AF in canines with short-time rapid right atrial pacing (RAP. However, the role of renal denervation on atrial remodeling is unclear. The aim of the present study was to explore the long-term effect of RSD on the atrial remodeling during prolonged RAP. Twenty mongrel dogs were implanted with a high-frequency cardiac pacemaker with a transvenous lead inserted into the right atrial appendage. The dogs were divided into three groups: a sham-operated group (n = 6, the chronic RAP (CRAP group (n = 7, and the CRAP+RSD group (n = 7. In the CRAP+RSD group, a pacemaker was implanted 6 weeks after RSD was performed bilaterally for recovery. RAP was maintained for 5 weeks in CRAP group and CRAP+RSD group. The plasma levels of Angiotensin II and aldosterone were significantly increased in CRAP group compared with sham-operated group, but the increasing trend was inhibited in CRAP+RSD group compared with CRAP group (P<0.05. Similarly, RSD suppressed the increasing trend that prolonged RAP produced in the left atrial levels of ANP, TNF-α and IL-6. Compared with the sham-operated group, the CRAP group had significantly increased levels of caspase-3, bax and Cx40 whereas the level of Bcl-2 decreased (P<0.05. RSD markedly reduced the upregulation of caspase-3, bax and Cx40 and the downregulation of Bcl-2 expression compared with the CRAP group (P<0.05. Picric acid-sirius red staining study suggested that RSD could markedly alleviate the lesion degree of cardic fibrosis induced by CRAP (P<0.05. Immunohistochemistry results showed that the densities of TH- and GAP43- positive nerves were significantly elevated in the CRAP group compared with the sham-operated group, while RSD operation signicantly inhibited the these changes produced by CRAP. These findings suggest that renal denervation could suppress the atrial remodeling after

  11. Results of Atrial Fibrillation Ablation in Patients With or Without a History of Atrial Flutter

    Institute of Scientific and Technical Information of China (English)

    Lu chunshan; Liu Xingpeng; Dong Jianzeng; Ma Changsheng

    2006-01-01

    Objectives There are two kind of atrial flutter during circumferential ablation for atrial fibrillation (AF): new onset left atrial flutter (LAFL), with a history of atrial flutter (AFL). What is the relationship of AFL and AF? Whether there are some differences in clinical course and mechanism between the new onset LAFL and the with a history of AFL remained unclear. The aim of this study was to assess the impacts of circumferential ablation on the occurrence of arrhythmias in follow-up in 2 groups:( 1 ) patients with a history of AFL and AF, and (2)patients with new onset LAFL. Methods Data from 465 patients who had circumferential pulmonary vein ablation (CPVA) or segmental pulmonary vein ablation (SPVA) were analyzed. Patients with a history of AFL ablation and patients who had concomitant AFL ablation were included from analysis. Forty-one patients constituted the history of AFL group (group 1, aged 57±13 years, 7 females) and twenty-eight patients constituted the new onset LAFL group (group 2, aged 55±12 years, 6 females). bipolar recordings were obtained from the tricuspid annulus, coronary sinus,interatrial septum and left atrium. Target sites were identified by early, fragmented or double potentials and by concealed entrainment. Linear lesions were created between target sites and nearby anatomical barriers (1) typical atrial flutter (cycle length, 242±39 ms). cavotricuspid isthmus ablation was performed.(2) new onset LAFL (cycle length, 282±153 ms). 20 episodes of AAFs were documented in 20/28 (71.4%)patients. Target sites were identified around pulmonary veins (n=10), gap in linear lesion (n=7), left atrial roof lines (1 case). For those cases the ablation line between PV and mitral annulus was performed.Patients in Group 2 had larger left atria, higher incidence of AFL pre-CPVA, and lower ejection fraction. Results There was no significant difference in post-CPVA AF recurrence between Groups 1 and 2, but AFL incidence after CPVA was higher in Group

  12. Left atrial dimension and atrial fibrillation in surgical heart disease patients

    Institute of Scientific and Technical Information of China (English)

    Kaihu Shi; Peisheng Liu; David Shek; Hongwei Shi; Ying Yu; Fei Ye; Xinwei Mu; Youxiang Zhang; Leiyang Zhang; Junjie Shao; Rui Wang

    2008-01-01

    Objective The effect of left atrial (LA) dimension on the occurrence of atrial fibrillation (AF) has been examined in some small studies.Less is known about the relationship of LA dimension,hemodynamic with AF during echocardiographic evaluation,especially,the flow dynamics in LA poorly described.The objective of this study was to investigate the relationship between LA dimension and the occurrence of AE Methods Two hundred and forty-five consecutive patients with heart disease scheduled to undergo open heart surgery were prospectively enrolled in the study.Patients were divided into 2 groups according to atrial fibrillation:AF group (n=148,99 men and 49 women,with a mean age 59.3+8.4 years),and no-AF group (n= 97,60 men and 37 womem).Echocardiography was performed before surgery.All measurements were performed following the American Society of Echocardiography recommendations.Results There were more patients with congestive heart failure in AF group than in no-AF group (45.9% vs 39.1%,P <0.05).The mean LA volume was 49.2±12.2 ml/m2 in AF group and 33.1±10.8 ml/m2 in no-AF group.There were also significant differences between two groups in left atrial end systolic dimension (LAESD) (50±13mm vs 27±14mm),left atrial end diastolic dimension (LAEDD) (79±17mm vs 53±13mm),PA pressure ( 41.3+11.6 mmHg vs 37.5±10.4 mmHg),and ratio of mitral E velocity and septal mitral annulus motion velocity (E/E') .The percentage of abnormal diastolic function grades (DGF) was also higher in AF than in no-AF group (89.9% versus 59.8% );.Conclusion Atrial fibrillation is associated more frequently with an increased LA dimension and more severe atrial hemodynamics disorder.(J Geriatr Cardiol 2008;5:11-4)

  13. Anomalous muscle bundle in the right atrium; Implication to trans atrial device closure

    Directory of Open Access Journals (Sweden)

    Saji Philip

    2017-09-01

    Full Text Available Intracavitary muscle bands or aberrant bands have been well described in all four chambers of the heart but rarely seen thick muscular band crossing right atrium. We report a case of devisable secundum atrial septal defect with an intra-atrial anomalous muscular band, crossing right atrial wall to the rim of the secundum atrial septal defect warranting surgical closure.

  14. Impact of dronedarone in atrial fibrillation and flutter on stroke reduction

    DEFF Research Database (Denmark)

    Christiansen, Christine Benn; Torp-Pedersen, Christian; Køber, Lars

    2010-01-01

    Dronedarone has been developed for treatment of atrial fibrillation (AF) or atrial flutter (AFL). It is an amiodarone analogue but noniodinized and without the same adverse effects as amiodarone.......Dronedarone has been developed for treatment of atrial fibrillation (AF) or atrial flutter (AFL). It is an amiodarone analogue but noniodinized and without the same adverse effects as amiodarone....

  15. Silent Atrial Fibrillation: Definition, Clarification, and Unanswered Issues.

    Science.gov (United States)

    Kennedy, Harold L

    2015-11-01

    Silent or subclinical asymptomatic atrial fibrillation has currently gained wide interest in the epidemiologic, neurologic and cardiovascular communities. The association of brief episodes of paroxysmal atrial fibrillation or surrogate atrial arrhythmias which predict future clinical adverse events have been established. Nevertheless there exists a confounding array of definitions to indicate its presence without discrete indication of which populations should be examined. Moreover the term "atrial fibrillation burden" (AFB) has emerged from such studies with a plethora of descriptions to prognosticate both arrhythmic and clinical adverse events. This presentation suggests clarification of diagnostic definitions associated with silent atrial fibrillation, and a more precise description of AFB. It examines the populations across the current disease and cardiovascular invasive therapeutic spectrum that lead to both silent atrial fibrillation and AFB. It describes the diagnostic methods of arrhythmia detection utilizing the surface ECG, subcutaneous ECG or intra-cardiac devices and their relationship in seeking meaningful arrhythmic markers of silent atrial fibrillation. Whereas a wide range of clinical risk factors of silent atrial fibrillation have been validated in the literature, there is an ongoing search for those arrhythmic risk factors that precisely identify and prognosticate outcome events in diverse populations at risk of atrial fibrillation and its complications. This presentation identifies this chaos, and focuses attention on the issues to be addressed to facilitate descriptive and comparative scientific studies in the future. It is a call to action specifically to the medical arrhythmic community and its specialty societies (i.e., ISHNE, HRS, EHRA) to begin a quest to unravel the arrhythmic quagmire associated with "silent atrial fibrillation."

  16. EFFECT OF METOPROLOL ON ATRIAL FIBRILLATORY RATE, ATRIOVENTRICULAR NODAL CONCEALED CONDUCTION, AND VENTRICULAR RESPONSE DURING ATRIAL-FIBRILLATION IN PIGS

    NARCIS (Netherlands)

    VANDENBERG, MP; DELANGEN, CDJ; CRIJNS, HJGM; HAAKSMA, J; BEL, KJ; WESSELING, H; LIE, KI

    1994-01-01

    We wished to elucidate the effect of beta-blockade on fibrillatory rate and atrioventricular (AV) nodal concealed conduction during atrial fibrillation (AF). Subsequent to determination of the effect on atrial functional refractoriness with the extrastimulus technique (basic cycle length 400 ms), th

  17. Effect of mmPs/TIMPs on Atrial Structural Remodeling in A Chronic Canine Atrial Fibrillation Model

    Institute of Scientific and Technical Information of China (English)

    Yang guirong; Zhang wei; Li li; Wang sujia; Zhu hui; Zhang yun

    2004-01-01

    @@ Objective Atrial fibrillation (AF) is commonly associatedwith atrial dilation and fibrosis, but the mechanism underlying these abnormalities remains unclear. The purpose of this study is to investigate the effect of matrix metalloproteinase-9 (mmP-9)and tissue in hibitor metalloproteinase -1 (TIMP-1) on extracellular matrix of atrium.

  18. Electrophysiological properties and the results of catheter ablation of symptomatic atrial tachyarrhythmia after surgical ablation of atrial fibrillation

    OpenAIRE

    Bockeria L.A.; Bockeria O.L.; Sergeev A.V.; Melikulov A.Kh.; Klimchuk I.Ya.; Temirbulatov I.A.; Fatulaev Z.F.

    2016-01-01

    Objective. To characterize electrophysiological properties of postablational arrhythmia and to assess shortand long-term efficacy of catheter radiofrequency ablation of these arrhythmias. Material and methods. We analyzed retrospectively 20 consecutive patients with highly symptomatic postsurgical atrial arrhythmia operated on valvular heart disease in conjunction with paroxysmal, persistent, longstanding persistent and permanent forms of atrial fibrillation during 2010–2013. Medi...

  19. Atrial-based pacing has no benefit over ventricular pacing in preventing atrial arrhythmias in adults with congenital heart disease

    NARCIS (Netherlands)

    Opic, P.; Yap, S.C.; Kranenburg, M. van; Dijk, A.P.J. van; Budts, W.; Vliegen, H.W.; Erven, L. van; Can, A.; Sahin, G.; Groot, N.M. de; Witsenburg, M.; Roos-Hesselink, J.W.

    2013-01-01

    AIMS: To determine whether atrial-based pacing prevents atrial arrhythmias in adults with congenital heart disease (CHD) compared with ventricular pacing. METHODS AND RESULTS: All adult CHD patients from four participating centres with a permanent pacemaker were identified. Patients with permanent a

  20. Progression of atrial fibrillation in the REgistry on Cardiac rhythm disORDers assessing the control of Atrial Fibrillation cohort

    DEFF Research Database (Denmark)

    De Vos, Cees B; Breithardt, Günter; Camm, A John;

    2012-01-01

    Paroxysmal atrial fibrillation (AF) may progress to persistent AF. We studied the clinical correlates and the effect of rhythm-control strategy on AF progression.......Paroxysmal atrial fibrillation (AF) may progress to persistent AF. We studied the clinical correlates and the effect of rhythm-control strategy on AF progression....

  1. Rapid slowing of the atrial fibrillatory rate after administration of AZD7009 predicts conversion of atrial fibrillation

    DEFF Research Database (Denmark)

    Aunes, Maria; Egstrup, Kenneth; Frison, Lars

    2014-01-01

    BACKGROUND: Effects on the atrial fibrillatory rate (AFR) were studied during infusion with the combined potassium and sodium channel blocker AZD7009. METHODS AND RESULTS: Patients with persistent atrial fibrillation (AF) were randomized to AZD7009 or placebo. Thirty-five patients converted...

  2. Ion channel remodeling is related to intraoperative atrial effective refractory periods in patients with paroxysmal and persistent atrial fibrillation

    NARCIS (Netherlands)

    Brundel, BJJM; Van Gelder, IC; Henning, RH; Tieleman, RG; Tuinenburg, AE; Wietses, M; Grandjean, JG; Van Gilst, WH; Crijns, HJGM

    2001-01-01

    Background-Sustained shortening of the atrial effective refractory period (AERP), probably due to reduction in the L-type calcium current, is a major factor in the initiation and maintenance of atrial fibrillation (AF), We investigated underlying molecular changes by studying the relation between ge

  3. Left atrial appendage occlusion with the Amplatzer Amulet for stroke prevention in atrial fibrillation: the first case in Greece.

    Science.gov (United States)

    Tzikas, Apostolos; Karagounis, Lambros; Bouktsi, Maria; Drevelegas, Antonios; Parcharidou, Despina; Ioannidis, Stathis; Krasopoulos, George; Giannakoulas, George

    2013-01-01

    Left atrial appendage (LAA) occlusion has been introduced into clinical practice as a valuable alternative to oral anticoagulation for stroke prevention in patients with non-valvular atrial fibrillation. In this case presentation we describe the first LAA occlusion in Greece using the Amplatzer Amulet device. We also briefly discuss issues related to procedural safety and multimodality imaging for LAA occlusion.

  4. Relationship between local production of microRNA-328 and atrial substrate remodeling in atrial fibrillation.

    Science.gov (United States)

    Soeki, Takeshi; Matsuura, Tomomi; Bando, Sachiko; Tobiume, Takeshi; Uematsu, Etsuko; Ise, Takayuki; Kusunose, Kenya; Yamaguchi, Koji; Yagi, Shusuke; Fukuda, Daiju; Yamada, Hirotsugu; Wakatsuki, Tetsuzo; Shimabukuro, Michio; Sata, Masataka

    2016-12-01

    The underlying mechanism of atrial substrate remodeling in atrial fibrillation (AF) remains unknown. In this study, we investigated whether local and systemic levels of microRNA (miR) might be associated with the presence of AF and with left atrial (LA) substrate properties. Blood from the periphery, pulmonary vein (PV), and left atrial appendage (LAA) was sampled from 30 patients with AF undergoing PV isolation, and from 10 control subjects with Wolff-Parkinson-White syndrome and without AF. We measured peripheral, PV, and LAA plasma levels of miR-1, -26, -133a, -328, and -590 by reverse transcription-polymerase chain reaction. LA global contact mapping during sinus rhythm was performed before PV isolation. Plasma levels of miR-328 were higher in patients with AF than in control subjects. Plasma miR-328 levels were significantly higher in the LAA than in the periphery and PV in patients with AF, but not in control subjects. Plasma miR-1 levels were also higher in the LAA than in the PV in AF patients. Interestingly, LAA plasma levels of miR-328 showed a positive correlation with the LA voltage zone index (area with voltage <0.5mV divided by total LA surface area) and a weak correlation with LA volume. Local production of miR-328 in the left atrium may be involved in the process of atrial remodeling in patients with AF. Copyright © 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

  5. Extra-atrial expression of the gene for atrial natriuretic factor.

    Science.gov (United States)

    Gardner, D G; Deschepper, C F; Ganong, W F; Hane, S; Fiddes, J; Baxter, J D; Lewicki, J

    1986-01-01

    Atrial natriuretic factor (ANF) is a group of peptides, originally isolated from the cardiac atria, that have a number of important effects on blood pressure, renal function, and salt balance. In the current study, expression of the ANF gene in certain extra-atrial tissues of the rat has been examined by radioimmunoassay of extracted ANF protein and by blot-hybridization, nuclease S1 analysis, and primer-extension analysis of the ANF mRNA. ANF peptides and mRNA were detected in cardiac ventricles, lung, and pituitary gland at levels generally less than or equal to 1% those of cardiac atria. The ANF transcripts in extra-atrial tissue appear to be very similar to those synthesized in the atria. They are polyadenylylated, are equivalent in overall length (950-1050 nucleotides), and have identical 5' termini. A secondary transcription start site mapping approximately 80 base pairs upstream from the primary start site is employed in atria and to a lesser extent in other tissues. The ANF transcript is present throughout the cardiac ventricles from apex to base and in the septum as well as the ventricular free walls. The transcript is more prevalent in the left ventricle and interventricular septum than in the right ventricle. Immunocytochemistry using various anti-rat ANF antibodies localized ANF immunoreactivity to the atrial myocytes; the ventricular myocytes, particularly along the endothelial surface of the ventricular chamber; perialveolar cells in the lung; and the gonadotropin-producing cells of the pituitary. The data indicate that the capacity for ANF gene expression extends beyond atrial tissue, albeit at much reduced levels, and may suggest alternative, perhaps paraendocrine, functions for the peptide in these tissues. Images PMID:2428040

  6. Minimally invasive surgery for atrial fibrillation.

    Science.gov (United States)

    Zembala, Michael O; Suwalski, Piotr

    2013-11-01

    Atrial fibrillation (AF) remains the most common cardiac arrhythmia, affecting nearly 2% of the general population worldwide. Minimally invasive surgical ablation remains one of the most dynamically evolving fields of modern cardiac surgery. While there are more than a dozen issues driving this development, two seem to play the most important role: first, there is lack of evidence supporting percutaneous catheter based approach to treat patients with persistent and long-standing persistent AF. Paucity of this data offers surgical community unparalleled opportunity to challenge guidelines and change indications for surgical intervention. Large, multicenter prospective clinical studies are therefore of utmost importance, as well as honest, clear data reporting. Second, a collaborative methodology started a long-awaited debate on a Heart Team approach to AF, similar to the debate on coronary artery disease and transcatheter valves. Appropriate patient selection and tailored treatment options will most certainly result in better outcomes and patient satisfaction, coupled with appropriate use of always-limited institutional resources. The aim of this review, unlike other reviews of minimally invasive surgical ablation, is to present medical professionals with two distinctly different, approaches. The first one is purely surgical, Standalone surgical isolation of the pulmonary veins using bipolar energy source with concomitant amputation of the left atrial appendage-a method of choice in one of the most important clinical trials on AF-The Atrial Fibrillation Catheter Ablation Versus Surgical Ablation Treatment (FAST) Trial. The second one represents the most complex approach to this problem: a multidisciplinary, combined effort of a cardiac surgeon and electrophysiologist. The Convergent Procedure, which includes both endocardial and epicardial unipolar ablation bonds together minimally invasive endoscopic surgery with electroanatomical mapping, to deliver best of the

  7. Radiofrequency ablation for treatment of atrial fibrillation.

    Science.gov (United States)

    Safaei, Nasser; Montazerghaem, Hossein; Azarfarin, Rasoul; Alizadehasl, Azin; Alikhah, Hossein

    2011-01-01

    Atrial Fibrillation (AF) is the most common cardiac arrhythmia which represents a major public health problem. The main purpose of this research is to evaluate the Radiofrequency (RF) ablation effects in the patients with chronic AF scheduled for cardiac surgery because of different heart diseases. The descriptive and prospective study was conducted on 60 patients with AF scheduled for surgery along with RF ablation. The data were collected by questionnaire and included: patients' age, sex, NYHA class, operation type, past medical history, type and cause of valvular heart disease, preoperative ECG (electrocardiogram), duration of surgery, clamping time, cardiopulmonary bypass, and RF ablation time. RF ablation was followed by the main operation. The follow up examination, ECG, and echocardiography were performed 3 and 6 months after operation. The mean age of patients was 48±10 years (18-71 years). Forty one patients had permanent AF and 19 had the persistent AF. The left ventricular ejection fraction was 48.27±9.75 percent before operation, and reached to 56.27±7.87 percent after the surgery (P<0.001). The mean NYHA class before the surgery was 2.83±0.68 which decreased to 1.34±0.46 6 months after the surgery with RF ablation (P<0.001). One patient (1.6%) died after surgery. Complete relief and freedom from AF recurrence was observed in 70% of patients in the mean follow up in 7 months after the surgery. The sinus rhythm with efficient atrial contraction was established in 100% of discharged patients. RF ablation is an effective procedure to cure atrial fibrillation in patients undergoing cardiac surgeries.

  8. Combined percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation for rheumatic mitral stenosis and atrial fibrillation

    Energy Technology Data Exchange (ETDEWEB)

    Murdoch, Dale, E-mail: dale_murdoch@health.qld.gov.au [The Prince Charles Hospital, Brisbane (Australia); The University of Queensland, Brisbane (Australia); McAulay, Laura [The Prince Charles Hospital, Brisbane (Australia); Walters, Darren L. [The Prince Charles Hospital, Brisbane (Australia); The University of Queensland, Brisbane (Australia)

    2014-11-15

    Rheumatic heart disease is a common cause of cardiovascular morbidity and mortality worldwide, mostly in developing countries. Mitral stenosis and atrial fibrillation often coexist, related to both structural and inflammatory changes of the mitral valve and left atrium. Both predispose to left atrial thrombus formation, commonly involving the left atrial appendage. Thromboembolism can occur, with devastating consequences. We report the case of a 62 year old woman with rheumatic heart disease resulting in mitral stenosis and atrial fibrillation. Previous treatment with warfarin resulted in life-threatening gastrointestinal bleeding and she refused further anticoagulant therapy. A combined procedure was performed, including percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation with the Atritech® Watchman® device. No thromboembolic or bleeding complications were encountered at one year follow-up. Long-term follow-up in a cohort of patients will be required to evaluate the safety and efficacy of this strategy.

  9. Heart failure after transvenous closure of atrial septal defect associated with atrial standstill and thiamine-responsive megaloblastic anemia.

    Science.gov (United States)

    Doğan, Vehbi; Senocak, Filiz; Orün, Utku Arman; Ceylan, Ozben

    2013-10-01

    Despite advances in device closure for atrial septal defect, post-closure heart failure remains a clinical problem in adult patients but is seen only rarely in children. An eight-year-old boy, who had been followed by a local pediatrician with the diagnosis of diabetes mellitus and congenital heart disease, was consulted to us for cardiac re-evaluation. Electrocardiography demonstrated absent P waves, and echocardiography revealed enlargement of the right ventricle and both atria and secundum atrial septal defect. With the diagnosis of atrial standstill, secundum atrial septal defect and thiamine-responsive megaloblastic anemia, acute heart failure developed after transvenous closure of the atrial septal defect, which improved dramatically with thiamine and supportive treatment.

  10. NASA's First Atrial Fibrillation Case - Deke Slayton

    Science.gov (United States)

    Tarver, William J.

    2010-01-01

    Concerns about heart dysrhythmia have been present since the earliest days of the US manned space program. While information about an astronaut's health is general kept private, one of the original seven American astronaut's health status was played out in a very public forum. Donald "Deke" Slayton was removed from the second manned space flight when it was discovered he had idiopathic atrial fibrillation. Referencing the original medical documents, details of how this was discovered and managed from the medical perspective will be reviewed. This is NASA's first heart dysrhythmia case in an astronaut and it proves quite interesting when placed in historic perspective.

  11. Atrial fibrillation in China: a brief review

    Institute of Scientific and Technical Information of China (English)

    MA Chang-sheng; DU Xin; JIANG Chen-xi

    2009-01-01

    @@ Atrial fibrillation (AF) is the most common heart rhythm disturbance encountered in clinical practice.It affects at least ten million Chinese, constituting a major public health epidemic. For the shortness of resource in the initial stage of new China and the chaos during the culture revolution, there was a scarcity of AF data on the Chinese population. However, Chinese physicians had never stopped exploring in this field, which has provided a solid foundation for today's flourishing development in the research of AF. This paper aims to review the major achievements in dealing with AF in the past 60 years in China, especially in the latest 15 years.

  12. Current approaches in atrial fibrillation treatment

    Directory of Open Access Journals (Sweden)

    Cenk Sarı

    2014-09-01

    Full Text Available Atrial fibrillation (AF is the most common sustained arrhythmia encountered in clinical practice. Its incidence increases with age. AF is classified into subtypes according to the duration and/or able to provide sinus rhytym. İnitially, patients should be evaluated for rhythm or rate control for appropriate treatment. Second stage of strategy aimed to investigate the feasibility of anticoagulation therapy. Recently, due to the progress made in treatment with rhythm control and anticoagulation therapy, either American or European guidelines have been renovated. These developments have taken place in the newly published guide. In this article, the current change in the management of AF is discussed.

  13. Fibrilación atrial: nuevos conceptos

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    Luis Gutiérrez-Jaikel

    2004-06-01

    Full Text Available La fibrilación atrial es la arritmia más frecuente en la práctica clínica, se presenta tanto en pacientes con cardiopatía estructural de base principalmente hipertensiva, isquémica y valvular, como en pacientes sin trastorno cardiaco de fondo al avanzar la edad. Debido a la morbilidad asociada a esta, es vital su reconocimiento temprano y el manejo adecuado, con la finalidad de reducir la incidencia de complicaciones asociadas y mejorar la calidad de vida de quienes la padecen.

  14. The polyuria of paroxysmal atrial tachycardia

    Science.gov (United States)

    Kinney, M. J.; Stein, R. M.; Discala, V. A.

    1974-01-01

    Two patients with paroxysmal atrial fibrillation and an associated polyuria were studied to delineate the mechanism of the increase in urine flow. A striking saluresis was noted in both patients. The increased sodium excretion was probably due to decreased sodium reabsorption, perhaps at proximal tubular nephron sites. This inhibition of sodium reabsorption could explain both the saluresis and some part or all of the polyuria. Re-evaluation of earlier case reports reveals patterns of concomitant salt and water excretion consistent with this mechanism. The saluresis cannot be explained by the previously favored hypothesis of antidiuretic hormone inhibition.

  15. Echocardiographic study of left atrial myxoma

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    Dalal J

    1979-01-01

    Full Text Available Four cases of left atrial myxoma were diagnosed pre-operatively by echocardiography. All cases showed characteristic echocardio-graphic features of variegated shadows behind the mitral valve in diastole and within the left atrium in systole. In two cases the my-xomas were surgically removed and confirmed on histology. In one case the post-operative echocardiogram showed complete dis-appearance of the abnormal shadows. Echocardiography is the most reliable method today for the diagnosis of a myxoma.

  16. Fibroblast growth factor-21 is positively associated with atrial fibrosis in atrial fibrillation patients with rheumatic heart disease.

    Science.gov (United States)

    Wang, Rui; Yi, Xin; Li, Xiaoyan; Jiang, Xuejun

    2015-01-01

    Fibroblast growth factor-21 (FGF-21) has been discovered as a strong hormone, plays an important role in lipid metabolism, glucose metabolism, associated with several diseases such as obesity, metabolic syndrome, diabetes mellitus, and cardiovascular events; however, no evidence is available concerning the relationship of FGF-21 and atrial fibrosis in patients with atrial fibrillation (AF) and rheumatic heart disease (RHD). Twenty-four rheumatic heart disease patients were divided into two groups, 12 cases with AF and 12 cases with sinus rhythm (SR). Clinical characteristics and blood samples were collected before surgery; right atrial appendage samples were taken in the surgery of valve replacement. HE staining was performed to determine cross-sectional area of atrial myocytes; Masson stained sections and mRNA levels of cardiac fibrosis biomarkers were used to evaluate the degree of cardiac fibrosis; the level of FGF-21 was evaluated via enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, and real-time polymerase chain reaction (PCR). Compared with SR group, cross-sectional area of atrial myocytes and collagen volume fraction were significantly increased in the atrial tissue of AF group. The distribution of FGF-21 in the AF group was remarkably higher than SR group. In addition, plasma and mRNA levels of FGF-21 in atrial tissue of AF showed the same trend as the result of immunohistochemistry. Using linear correlation analysis, the expression level of FGF-21 was found to be positively related to the degree of atrial fibrosis. FGF-21 might involve in the development and maintenance of atrial fibrosis in atrial fibrillation with rheumatic heart disease, and FGF-21 could be used as a novel biomarker to evaluate myocardial fibrosis in the future.

  17. Atrial conduction times and left atrial mechanical functions and their relation with diastolic function in prediabetic patients

    Science.gov (United States)

    Gudul, Naile Eris; Karabag, Turgut; Sayin, Muhammet Rasit; Bayraktaroglu, Taner; Aydin, Mustafa

    2017-01-01

    Background/Aims The aim of this study was to investigate atrial conduction times and left atrial mechanical functions, the noninvasive predictors of atrial fibrillation, in prediabetic patients with impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). Methods Study included 59 patients (23 males, 36 females; mean age 52.5 ± 10.6 years) diagnosed with IFG or IGT by the American Diabetes Association criteria, and 43 healthy adults (22 males, 21 females; mean age 48.5 ± 12.1 years). Conventional and tissue Doppler echocardiography were performed. The electromechanical delay parameters were measured from the onset of the P wave on the surface electrocardiogram to the onset of the atrial systolic wave on tissue Doppler imaging from septum, lateral, and right ventricular annuli. The left atrial volumes were calculated by the disk method. Left atrial mechanical functions were calculated. Results The mitral E/A and E’/A’ ratios measured from the lateral and septal annuli were significantly lower in the prediabetics compared to the controls. The interatrial and left atrial electromechanical delay were significantly longer in prediabetic group compared to the controls. Left atrial active emptying volume (LAAEV) and fraction (LAAEF) were significantly higher in the prediabetics than the controls. LAAEV and LAAEF were significantly correlated with E/A, lateral and septal E’/A’. Conclusions In the prediabetic patients, the atrial conduction times and P wave dispersion on surface electrocardiographic were longer before the development of overt diabetes. In addition, the left atrial mechanical functions were impaired secondary to a deterioration in the diastolic functions in the prediabetic patients. PMID:27919159

  18. Detecting and Diagnosing Atrial Fibrillation (D2AF): study protocol for a cluster randomised controlled trial

    OpenAIRE

    Uittenbogaart, Steven B.; Verbiest-van Gurp, Nicole; Erkens, Petra M. G.; Lucassen, Wim A M; Knottnerus, J. André; Winkens, Bjorn; van Weert, Henk C P M; Stoffers, Henri E. J. H.

    2015-01-01

    Background Atrial fibrillation is a common cause of stroke and other morbidity. Adequate treatment with anticoagulants reduces the risk of stroke by 60 %. Early detection and treatment of atrial fibrillation could prevent strokes. Atrial fibrillation is often asymptomatic and/or paroxysmal. Case-finding with pulse palpation is an effective screening method, but new methods for detecting atrial fibrillation have been developed. To detect paroxysmal atrial fibrillation ambulatory rhythm recordi...

  19. A Genetic Algorithm Optimization Method for Mapping Non-Conducting Atrial Regions: A Theoretical Feasibility Study.

    Science.gov (United States)

    Shiff, Shai; Swissa, Moshe; Zlochiver, Sharon

    2016-03-01

    Atrial ablation has been recently utilized for curing atrial fibrillation. The success rate of empirical ablation is relatively low as often the exact locations of the arrhythmogenic sources remain elusive. Guided ablation has been proposed to improve ablation technique by providing guidance regarding the potential localization of the sources; yet to date no main technological solution has been widely adopted as an integral part of the ablation process. Here we propose a genetic algorithm optimization technique to map a major arrhythmogenic substance-non-conducting regions (NCRs). Excitation delays in a set of electrodes of known locations are measured following external tissue stimulation, and the spatial distribution of obstacles that is most likely to yield the measured delays is reconstructed. A forward problem module was solved to provide synthetic time delay measurements using a 2D human atrial model with known NCR distribution. An inverse genetic algorithm module was implemented to optimally reconstruct the locations of the now unknown obstacle distribution using the synthetic measurements. The performance of the algorithm was demonstrated for several distributions varying in NCR number and shape. The proposed algorithm was found robust to measurements with a signal-to-noise ratio of at least -20 dB, and for measuring electrodes separated by up to 3.2 mm. Our results support the feasibility of the proposed algorithm in mapping NCRs; nevertheless, further research is required prior to clinical implementation for incorporating more complex atrial tissue geometrical configurations as well as for testing the algorithm with experimental data.

  20. Arum-type of arbuscular mycorrhizae, dark septate endophytes and Olpidium spp. in fine roots of container-grown seedlings of Sorbus torminalis (Rosaceae

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    Roman M. Bzdyk

    2016-06-01

    Full Text Available The aim of this study was to determine the mycorrhizal status of nursery seedlings of the wild service tree (Sorbus torminalis, which belongs to the Rosaceae family. Its mycorrhizal associations are still fragmentarily known, and data from the few existing studies indicate that it forms ectomycorrhizal symbiosis (ECM. We analyzed the degree of mycorrhizal colonization of thirty 2-year-old container-grown S. torminalis nursery seedlings, which belonged to three single-tree progenies. The roots were dominated by arbuscular mycorrhizae (AM, with the morphology of the Arum-type containing arbuscules, vesicles and hyphae; however, no ECM structures were found. The degree of root colonization of the analyzed seedlings by AM fungi was 83.6% and did not differ significantly between the three single-tree progenies. In addition to AM, structures of dark septate endophytes (0.7% and sporangia of Olpidium spp. (1.1% were found in wild service tree roots. In agreement with previous studies, we confirmed arbuscular mycorrhizae for S. torminalis. Moreover, this is the first report that roots of this Sorbus species show the Arum-type morphology of AM and are associated with Olpidium species.

  1. A new species of Harpophora (Magnaporthaceae) recovered from healthy wild rice (Oryza granulata) roots, representing a novel member of a beneficial dark septate endophyte.

    Science.gov (United States)

    Yuan, Zhi-Lin; Lin, Fu-Cheng; Zhang, Chu-Long; Kubicek, Christian P

    2010-06-01

    A survey of the endophytic fungal community of wild rice (Oryza granulata) in China was conducted. Two isolates recovered from healthy roots are assumed to be dark septate endophytes (DSEs). They are morphologically similar to species from the genus Harpophora and are identified as a new species, Harpophora oryzae, based on the molecular phylogeny and morphological characteristics. A neighbor-joining tree constructed from ITS-5.8S rRNA gene regions reveals that H. oryzae forms a distinctive subclade within the genus Harpophora, and is not genetically close to other species of Harpophora. Harpophora oryzae exhibits a moderate growth rate, with a frequent production of rope-like strands. It sporulates readily on artificial medium. Phialides are usually flask or bottle shaped and occur singly along hyphae or laterally and terminally on branched, hyaline to brown conidiophores, and also form whorls on metulae. Conidiophores are mostly branched with a slightly thickened wall, varying in dimensions. Conidia are one-celled and hyaline, most of them being falcate and strongly curved. The morphological differences between Harpophora spp. and Harpophora-like anamorphs representing different orders are also discussed. An in vitro inoculation test showed that H. oryzae may contribute towards improving rice (Oryza sativa L.) growth. Microscopic inspection of roots and phylogenetic placement of isolates further confirmed that H. oryzae represents a novel member of DSEs.

  2. Dark septate endophyte (DSE) fungi isolated from metal polluted soils: their taxonomic position, tolerance, and accumulation of heavy metals in vitro.

    Science.gov (United States)

    Zhang, Yujie; Zhang, Yan; Liu, Maojun; Shi, Xiaodong; Zhao, Zhiwei

    2008-12-01

    To understand the possible role of the plant root associated fungi on metal tolerance, their role in the uptake of heavy metals and the potential transfer of these metal ions to the plant, three strains of dark septate endophytic (DSE) fungi were isolated from a waste smelter site in southwest China, and one strain was isolated from a non-contaminated site. According to molecular phylogenetic analysis of the ITS 1-5.8S rDNA-ITS 2 gene regions and morphological characteristics, one is identified as Exophiala pisciphila, and the other three are non-sporulating fungi under the experiment condition with the nearest phylogenetic affinities to the Thysanorea papuana strain EU041814. Tolerance and accumulation abilities of the three DSE strains for metals were investigated in liquid culture. Minimum inhibitory concentrations (MIC) of Pb, Zn, and Cd were determined. It was demonstrated that the tolerance of the DSE strains varied between metal species and strains. The E. pisciphila strain is able to accumulate lead and cadmium over 20% and 5% of dry weight of biomass, respectively. Partial of the sequestrated metals can be washed with CaCh. Morphological and enzyme activity changes taking place in the presence of excessive Pb, Cd, and/or Zn also indicate that the mechanism of heavy metal tolerance and accumulation of the DSE strains would be a complex process. The findings indicated promising tolerance and accumulation of the DSE strains with potential values in metal cycling and restoration of soil and water system.

  3. Phylogeny of Phaeomollisia piceae gen. sp. nov.: a dark, septate, conifer-needle endophyte and its relationships to Phialocephala and Acephala.

    Science.gov (United States)

    Grünig, Christoph R; Queloz, Valentin; Duò, Angelo; Sieber, Thomas N

    2009-02-01

    Dark, septate endophytes (DSE) were isolated from roots and needles of dwarf Picea abies and from roots of Vaccinium spp. growing on a permafrost site in the Jura Mountains in Switzerland. Two of the isolates sporulated after incubation for more than one year at 4 degrees C. One of them was a hitherto undescribed helotialean ascomycete Phaeomollisia piceae gen. sp. nov., the other was a new species of Phialocephala, P. glacialis sp. nov. Both species are closely related to DSE of the Phialocephala fortinii s. lat.-Acephala applanata species complex (PAC) as revealed by phylogenetic analyses of the ITS and 18S rDNA regions. Morphologically dissimilar fungi, such as Vibrissea and Loramyces species, are phylogenetically also closely linked to the new species and the PAC. Cadophora lagerbergii and C. (Phialophora) botulispora are moved to Phialocephala because Phialocephala dimorphospora and P. repens are the closest relatives. Several Mollisia species were closely related to the new species and the PAC according to ITS sequence comparisons. One DSE from needles of Abies alba and one from shoots of Castanea sativa formed Cystodendron anamorphs in culture. Their identical 18S sequences and almost identical ITS sequences indicated Mollisia species as closest relatives, suggesting that Mollisia species are highly euryoecious.

  4. Host species and strain combination determine growth reduction of spruce and birch seedlings colonized by root-associated dark septate endophytes.

    Science.gov (United States)

    Reininger, Vanessa; Grünig, Christoph R; Sieber, Thomas N

    2012-04-01

    Interactions of Betula pendula and Picea abies with dark septate endophytes of the Phialocephala fortinii-Acephala applanata species complex (PAC) were studied. PAC are ubiquitous fungal root symbionts of many woody plant species but their ecological role is largely unknown. Sterile birch and spruce seedlings in monoculture and mixed culture were exposed to four PAC strains, added either singularly or paired in all possible combinations at 18°C and 23°C. Plant and fungal biomass was determined after 4 months. The most significant factors were strain and host combination. One of the strains significantly reduced biomass gain of spruce but not of birch. Plant biomass was negatively correlated with total endophytic fungal biomass in half of the strain - plant combinations. Endophytic PAC biomass was four times higher in spruce (≈ 40 mg g(-1) drw) than in birch (≈ 10 mg g(-1) drw). Competition between strains was strain-dependent with some strains significantly reducing colonization density of other strains, and, thus, attenuating adverse effects of 'pathogenic' strains on plant growth in some strain - plant combinations. Biomass gain of spruce but not of birch was significantly reduced at higher temperature. In conclusion, host, fungal genotype, colonization density and presence of a competing PAC strain were the main determining factors for plant growth.

  5. Communities of Cultivable Root Mycobionts of the Seagrass Posidonia oceanica in the Northwest Mediterranean Sea Are Dominated by a Hitherto Undescribed Pleosporalean Dark Septate Endophyte.

    Science.gov (United States)

    Vohník, Martin; Borovec, Ondřej; Kolařík, Miroslav

    2016-02-01

    Seagrasses, a small group of submerged marine macrophytes, were reported to lack mycorrhizae, i.e., the root-fungus symbioses most terrestrial plants use for nutrient uptake. On the other hand, several authors detected fungal endophytes in seagrass leaves, shoots, rhizomes, and roots, and an anatomically and morphologically unique dark septate endophytic (DSE) association has been recently described in the roots of the Mediterranean seagrass Posidonia oceanica. Nevertheless, the global diversity of seagrass mycobionts is not well understood, and it remains unclear what fungus forms the DSE association in P. oceanica roots. We isolated and determined P. oceanica root mycobionts from 11 localities in the northwest Mediterranean Sea with documented presence of the DSE association and compared our results with recent literature. The mycobiont communities were low in diversity (only three species), were dominated by a single yet unreported marine fungal species (ca. 90 % of the total 177 isolates), and lacked common terrestrial and freshwater root mycobionts. Our phylogenetic analysis suggests that the dominating species represents a new monotypic lineage within the recently described Aigialaceae family (Pleosporales, Ascomycota), probably representing a new genus. Most of its examined colonies developed from intracellular microsclerotia occupying host hypodermis and resembling microsclerotia of terrestrial DSE fungi. Biological significance of this hitherto overlooked seagrass root mycobiont remains obscure, but its presence across the NW Mediterranean Sea and apparent root intracellular lifestyle indicate an intriguing symbiotic relationship with the dominant Mediterranean seagrass. Our microscopic observations suggest that it may form the DSE association recently described in P. oceanica roots.

  6. Negative effects on survival and performance of Norway spruce seedlings colonized by dark septate root endophytes are primarily isolate-dependent.

    Science.gov (United States)

    Tellenbach, Christoph; Grünig, Christoph R; Sieber, Thomas N

    2011-09-01

    Root endophytes are common and genetically highly diverse suggesting important ecological roles. Yet, relative to above-ground endophytes, little is known about them. Dark septate endophytic fungi of the Phialocephala fortinii s.l.-Acephala applanata species complex (PAC) are ubiquitous root colonizers of conifers and Ericaceae, but their ecological function is largely unknown. Responses of Norway spruce seedlings of two seed provenances to inoculations with isolates of four PAC species were studied in vitro. In addition, isolates of Phialocephala subalpina from two populations within and one outside the natural range of Norway spruce were also included to study the effect of the geographic origin of P. subalpina on host response. The interaction of PAC with Norway spruce ranged from neutral to highly virulent and was primarily isolate-dependent. Variation in virulence was much higher within than among species, nonetheless only isolates of P. subalpina were highly virulent. Disease caused by P. subalpina genotypes from the native range of Norway spruce was more severe than that induced by genotypes from outside the natural distribution of Norway spruce. Virulence was not correlated with the phylogenetic relatedness of the isolates but was positively correlated with the extent of fungal colonization as measured by quantitative real-time PCR.

  7. Diverse strategies conferring extreme cadmium (Cd) tolerance in the dark septate endophyte (DSE), Exophiala pisciphila: evidence from RNA-seq data.

    Science.gov (United States)

    Zhao, Dake; Li, Tao; Shen, Mi; Wang, Junling; Zhao, Zhiwei

    2015-01-01

    Dark septate endophytes (DSE) ubiquitously colonize the roots of plants growing in extreme heavy metals (HMs)-contaminated soils. Little is known about the overall molecular response of DSE to excessive HMs. Therefore, RNA-seq was performed through Illumina Hiseq 2000 sequencing based on two cDNA libraries of the DSE strain Exophiala pisciphila, cultured under cadmium (Cd)-free and Cd-stressed conditions, and 21,376 unigenes were generated. In total, 575 differentially expressed genes (DEGs) were obtained. Approximately 40% of the DEGs (228 unigenes) were involved in 10 well-known HMs-tolerant pathways, conferring the extreme cadmium (Cd) tolerance of E. pisciphila, including metal ion binding and transportation, organic acid metabolism and transportation, reactive oxygen species (ROS) scavenging, redox homeostasis, transcription factors production, sulfate assimilation, DNA repair and cell wall integrity maintenance, etc. Our results indicate that integral tactics associated with the collaboration of extracellular and intracellular mechanisms contribute to the enhanced HMs tolerance of this fungus. This study represents the first investigation of the transcriptome of DSE under Cd stress, and our results provide valuable information for future molecular studies of HMs tolerance in fungi.

  8. Septins are important for cell polarity, septation and asexual spore formation in Neurospora crassa and show different patterns of localisation at germ tube tips.

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    Adokiye Berepiki

    Full Text Available Septins are GTP-binding cytoskeletal proteins that contribute to cell polarity, vesicle trafficking, cytokinesis and cell morphogenesis. Here we have characterised the six septins encoded by the genome of the model filamentous fungus Neurospora crassa. Analysis of septin null mutants demonstrated that septins limit the sites of emergence of germ tubes and are important for septation and conidiation in N. crassa. Septins constituted a range of different higher-order structures in N. crassa - rings, loops, fibres, bands, and caps - which can co-exist within the same cell. They showed different patterns of localisation at germ tube tips, with GFP-CDC-10 and CDC-11-GFP forming a subapical collar with lower signal intensity at the tip apex, CDC-3-GFP and CDC-12-GFP organized as a cap at the tip apex and GFP-ASP-1 forming an extended subapical collar. Purification of the septin complex and mass spectrometry of isolated proteins revealed that the septin complex consists predominantly of CDC-3, CDC-10, CDC-11 and CDC-12. Immunoprecipitation of the putative septin ASP-1 revealed that this protein interacts with the core septin complex.

  9. A Laminin G-EGF-Laminin G module in Neurexin IV is essential for the apico-lateral localization of Contactin and organization of septate junctions.

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    Swati Banerjee

    Full Text Available Septate junctions (SJs display a unique ultrastructural morphology with ladder-like electron densities that are conserved through evolution. Genetic and molecular analyses have identified a highly conserved core complex of SJ proteins consisting of three cell adhesion molecules Neurexin IV, Contactin, and Neuroglian, which interact with the cytoskeletal FERM domain protein Coracle. How these individual proteins interact to form the septal arrays that create the paracellular barrier is poorly understood. Here, we show that point mutations that map to specific domains of neurexin IV lead to formation of fewer septae and disorganization of SJs. Consistent with these observations, our in vivo domain deletion analyses identified the first Laminin G-EGF-Laminin G module in the extracellular region of Neurexin IV as necessary for the localization of and association with Contactin. Neurexin IV protein that is devoid of its cytoplasmic region is able to create septae, but fails to form a full complement of SJs. These data provide the first in vivo evidence that specific domains in Neurexin IV are required for protein-protein interactions and organization of SJs. Given the molecular conservation of SJ proteins across species, our studies may provide insights into how vertebrate axo-glial SJs are organized in myelinated axons.

  10. Imaging atrial arrhythmic intracellular calcium in intact heart.

    Science.gov (United States)

    Xie, Wenjun; Santulli, Gaetano; Guo, Xiaoxiao; Gao, Melanie; Chen, Bi-Xing; Marks, Andrew R

    2013-11-01

    Abnormalities in intracellular Ca(2+) signaling have been proposed to play an essential role in the pathophysiology of atrial arrhythmias. However, a direct observation of intracellular Ca(2+) in atrial myocytes during atrial arrhythmias is lacking. Here, we have developed an ex vivo model of simultaneous Ca(2+) imaging and electrocardiographic recording in cardiac atria. Using this system we were able to record atrial arrhythmic intracellular Ca(2+) activities. Our results indicate that atrial arrhythmias can be tightly linked to intracellular Ca(2+) waves and Ca(2+) alternans. Moreover, we applied this strategy to analyze Ca(2+) signals in the hearts of WT and knock-in mice harboring a 'leaky' type 2 ryanodine receptor (RyR2-R2474S). We showed that sarcoplasmic reticulum (SR) Ca(2+) leak increases the susceptibility to Ca(2+) alternans and Ca(2+) waves increasing the incidence of atrial arrhythmias. Reduction of SR Ca(2+) leak via RyR2 by acute treatment with S107 reduced both Ca(2+) alternans and Ca(2+) waves, and prevented atrial arrhythmias.

  11. Atrial natriuretic polypeptide-like material in rat lung

    Energy Technology Data Exchange (ETDEWEB)

    Chang, J.K.; Chang, D.; Xie, C.W.; Song, D.L.; Li, X.R.; Zhang, S.X.; Wang, T.L.; Tang, J.

    1986-03-05

    Atrial natriuretic polypeptide-like immunoreactive material (ANP-IR) was found in rat lung by radioimmunoassay, with the concentration ranging from 0.6-1.2 pmol/g of tissue in each lobe. PAP-immunohistochemical study demonstrated that specific staining of granules for ..cap alpha..-human ANP are mainly located in the muscular layer of the pulmonary vein. Fractionation of lung extract by gel filtration and reserve phase HPLC revealed the presence of multiple forms of ANP-IR, which possibly possessed molecular structure partially different from rat ANP, atriopeptin I and III. Intravenous injection of lung extract induced potent diuresis and natriuresis in rats. These responses could be abolished when the lung extract was preincubated with antiserum for ..cap alpha..-human ANP. Specific binding sites for /sup 125/I-labeled rat ANP were also found in lung membrane preparation by radioreceptor assay. Incubation of synthetic atriopeptin III (10/sup -9/ to 10/sup -6/M) with lung tissue induced 1-28 fold increase in lung cGMP content. The results suggest that ANP-IR and its receptors existing in rat lung may be involved in the regulation of pulmonary function and have a synergic effect with ANP of cardiac origin in the control of water-electrolytes balance.

  12. Revealing kinetics and state-dependent binding properties of IKur-targeting drugs that maximize atrial fibrillation selectivity

    Science.gov (United States)

    Ellinwood, Nicholas; Dobrev, Dobromir; Morotti, Stefano; Grandi, Eleonora

    2017-09-01

    The KV1.5 potassium channel, which underlies the ultra-rapid delayed-rectifier current (IKur) and is predominantly expressed in atria vs. ventricles, has emerged as a promising target to treat atrial fibrillation (AF). However, while numerous KV1.5-selective compounds have been screened, characterized, and tested in various animal models of AF, evidence of antiarrhythmic efficacy in humans is still lacking. Moreover, current guidelines for pre-clinical assessment of candidate drugs heavily rely on steady-state concentration-response curves or IC50 values, which can overlook adverse cardiotoxic effects. We sought to investigate the effects of kinetics and state-dependent binding of IKur-targeting drugs on atrial electrophysiology in silico and reveal the ideal properties of IKur blockers that maximize anti-AF efficacy and minimize pro-arrhythmic risk. To this aim, we developed a new Markov model of IKur that describes KV1.5 gating based on experimental voltage-clamp data in atrial myocytes from patient right-atrial samples in normal sinus rhythm. We extended the IKur formulation to account for state-specificity and kinetics of KV1.5-drug interactions and incorporated it into our human atrial cell model. We simulated 1- and 3-Hz pacing protocols in drug-free conditions and with a [drug] equal to the IC50 value. The effects of binding and unbinding kinetics were determined by examining permutations of the forward (kon) and reverse (koff) binding rates to the closed, open, and inactivated states of the KV1.5 channel. We identified a subset of ideal drugs exhibiting anti-AF electrophysiological parameter changes at fast pacing rates (effective refractory period prolongation), while having little effect on normal sinus rhythm (limited action potential prolongation). Our results highlight that accurately accounting for channel interactions with drugs, including kinetics and state-dependent binding, is critical for developing safer and more effective pharmacological anti

  13. Atrial Fibrillation Predictors: Importance of the Electrocardiogram.

    Science.gov (United States)

    German, David M; Kabir, Muammar M; Dewland, Thomas A; Henrikson, Charles A; Tereshchenko, Larisa G

    2016-01-01

    Atrial fibrillation (AF) is the most common arrhythmia in adults and is associated with significant morbidity and mortality. Substantial interest has developed in the primary prevention of AF, and thus the identification of individuals at risk for developing AF. The electrocardiogram (ECG) provides a wealth of information, which is of value in predicting incident AF. The PR interval and P wave indices (including P wave duration, P wave terminal force, P wave axis, and other measures of P wave morphology) are discussed with regard to their ability to predict and characterize AF risk in the general population. The predictive value of the QT interval, ECG criteria for left ventricular hypertrophy, and findings of atrial and ventricular ectopy are also discussed. Efforts are underway to develop models that predict AF incidence in the general population; however, at present, little information from the ECG is included in these models. The ECG provides a great deal of information on AF risk and has the potential to contribute substantially to AF risk estimation, but more research is needed.

  14. [Progress of anticoagulation therapy in atrial fibrillation].

    Science.gov (United States)

    Hernández Olmedo, Miguel; Suárez Fernández, Carmen

    2015-08-07

    Atrial fibrillation is currently a very prevalent disease and it represents one of the most common causes of disabling stroke. Antithrombotic therapies have reduced the incidence of this complication although they pose many limitations and difficulties. As a result, a large number of high risk patients do not receive an appropriate treatment. In recent years, four new oral anticoagulants (NOAC) with relevant advantages in comparison to vitaminK antagonists have been released. Four large phaseiii clinical trials have demonstrated that NOAC are at least as safe and efficacious as warfarin in stroke prevention in non-valve atrial fibrillation patients with moderate-high thrombotic risk, being their main advantage the reduction in intracranial hemorrhage. The arrival of these drugs has caused great expectations in the management of these patients but also new doubts. Lacking data in some subgroups of frail patients, the absence of specific antidotes available and specially their high cost represent nowadays the main limitations for their generalization. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  15. Right Atrial Metastatic Melanoma with Unknown Primaries

    Directory of Open Access Journals (Sweden)

    Robin Kuriakose

    2015-01-01

    Full Text Available A 54-year-old male with history of anemia and rheumatoid arthritis presented with a three-month history of dyspnea on exertion and lower extremity edema. Patient was referred for a transthoracic echocardiogram that revealed a large right atrial mass with reduced ejection fraction of 40% and an incidental large liver mass. Subsequent cardiac MRI revealed a lobulated right atrial mass measuring 5.4 cm × 5.3 cm with inferior vena cava compression and adjacent multiple large liver lesions confirmed to be malignant melanoma through biopsy. Interestingly, no primaries were found in the patient. PET/CT imaging displayed hypermetabolic masses within the right atrium and liver that likely represent metastases, as well as bilateral pleural effusions, most likely due to heart failure. Preoperative coronary angiogram demonstrated perfusion to the mass by a dense network of neovasculature arising from the mid right coronary artery. The cardiac melanoma was surgically removed, and the right atrium was reconstructed with a pericardial patch. After surgery, all cardiac chambers appeared normal in size and function with associated moderate tricuspid regurgitation. The patient is currently being administered ipilimumab for systemic therapy of metastatic melanoma.

  16. [Metabolic syndrome and chronic persistent atrial fibrillation].

    Science.gov (United States)

    Onuchina, E L; Solov'ev, O V; Mochalova, O V; Kononov, S K; Onuchin, S G

    2011-01-01

    The aim of the study was to elucidate specific features of chronic recurrent atrial fibrillation (AF) in patients with metabolic syndrome (MS) and disturbed carbohydrate metabolism compared with AF patients without MS. It enrolled 145 patients aged 44-83 years: 117 with abdominal obesity (BMI >30 kg/m2, waist circumference >80 and 94 cm in women and men respectively) including 30 without metabolic disturbances; 35 with impaired glucose tolerance (IGT), 52 with type 2 DM, and 28 controls without MS. Parameters measured included frequency and severity of AF, carbohydrate and lipid metabolism, albuminurea, C-reactive peptide level, quality of AH control, results of echocardiography and 24 hour ECG monitoring (sinus rhythm), and insulin resistance index (HOMA IRindex). Groups of AF and MS patients were dominated by women. The frequency and severity of AF relapses in MS patients were higher than in controls (especially in the presence of IGT and DM). IGT and DM2 associated with structural changes in myocardium (left atrial dilatation, prevalence of LV concentric hypertrophy, diastolic dysfunction) coupled to higher systolic AH and marked metabolic disorders (hyperglycemia, IR, elevated microalbuminurea and C-reactive protein level, dyslipidemia). These conditions contribute to the frequency and severity of AF relapses. Development of AF in MS is a multifactor problem necessitating strict control of AH, dyslipidemia, DM2 and IGT, reduction of body weight and abdominal obesity.

  17. Left Atrial Appendage Occlusion for Stroke Prevention.

    Science.gov (United States)

    Chanda, Arijit; Reilly, John P

    More than 2.3 million adults in the United States have atrial fibrillation (AF), which exposes them to a 5-fold increased risk of stroke. The left atrial appendage (LAA) appears to be the source of thrombus formation in the vast majority of these patients. Anticoagulation significantly reduces the risk of stroke, but often we encounter patients who have absolute or relative contraindication to anticoagulation. Percutaneous LAA exclusion offers an alternative to anticoagulation to decrease the risk of stroke. Three device systems are currently available in the United States. The WATCHMAN® device is the most studied and approved by Food and Drug Administration (FDA) to be used in patients with AF unsuitable for anticoagulation who are at a high risk of stroke. The Amulet® device is currently being used as part of the AMPLATZER® Amulet® LAA Occluder trial, which is a non-inferiority randomized trial comparing the Amulet® to the WATCHMAN® device. The third device in use is the LARIAT®, which is an FDA approved snare and pre-tied stich system. It is used to approximate soft tissue which in this case is the LAA. It is a hybrid system and requires both epicardial and endocardial access. The main obstacle to percutaneous LAA closure is procedural related complications, which can be minimized with optimum operator experience. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Clinical characteristics, management, and control of permanent vs. nonpermanent atrial fibrillation: insights from the RealiseAF survey.

    LENUS (Irish Health Repository)

    Murin, Jan

    2014-01-01

    Atrial fibrillation can be categorized into nonpermanent and permanent atrial fibrillation. There is less information on permanent than on nonpermanent atrial fibrillation patients. This analysis aimed to describe the characteristics and current management, including the proportion of patients with successful atrial fibrillation control, of these atrial fibrillation subsets in a large, geographically diverse contemporary sample.

  19. Atrial Arrhythmias in Astronauts - Summary of a NASA Summit

    Science.gov (United States)

    Barr, Yael R.; Watkins, Sharmila D.; Polk, J. D.

    2010-01-01

    Background and Problem Definition: To evaluate NASA s current standards and practices related to atrial arrhythmias in astronauts, Space Medicine s Advanced Projects Section at the Johnson Space Center was tasked with organizing a summit to discuss the approach to atrial arrhythmias in the astronaut cohort. Since 1959, 11 cases of atrial fibrillation, atrial flutter, or supraventricular tachycardia have been recorded among active corps crewmembers. Most of the cases were paroxysmal, although a few were sustained. While most of the affected crewmembers were asymptomatic, those slated for long-duration space flight underwent radiofrequency ablation treatment to prevent further episodes of the arrhythmia. The summit was convened to solicit expert opinion on screening, diagnosis, and treatment options, to identify gaps in knowledge, and to propose relevant research initiatives. Summit Meeting Objectives: The Atrial Arrhythmia Summit brought together a panel of six cardiologists, including nationally and internationally renowned leaders in cardiac electrophysiology, exercise physiology, and space flight cardiovascular physiology. The primary objectives of the summit discussions were to evaluate cases of atrial arrhythmia in the astronaut population, to understand the factors that may predispose an individual to this condition, to understand NASA s current capabilities for screening, diagnosis, and treatment, to discuss the risks associated with treatment of crewmembers assigned to long-duration missions or extravehicular activities, and to discuss recommendations for prevention or management of future cases. Summary of Recommendations: The summit panel s recommendations were grouped into seven categories: Epidemiology, Screening, Standards and Selection, Treatment of Atrial Fibrillation Manifesting Preflight, Atrial Fibrillation during Flight, Prevention of Atrial Fibrillation, and Future Research

  20. A roadmap to improve the quality of atrial fibrillation management : proceedings from the fifth Atrial Fibrillation Network/European Heart Rhythm Association consensus conference

    NARCIS (Netherlands)

    Kirchhof, Paulus; Breithardt, Guenter; Bax, Jeroen; Benninger, Gerlinde; Blomstrom-Lundqvist, Carina; Boriani, Giuseppe; Brandes, Axel; Brown, Helen; Brueckmann, Martina; Calkins, Hugh; Calvert, Melanie; Christoffels, Vincent; Crijns, Harry; Dobrev, Dobromir; Ellinor, Patrick; Fabritz, Larissa; Fetsch, Thomas; Freedman, S. Ben; Gerth, Andrea; Goette, Andreas; Guasch, Eduard; Hack, Guido; Haegeli, Laurent; Hatem, Stephane; Haeusler, Karl Georg; Heidbuechel, Hein; Heinrich-Nols, Jutta; Hidden-Lucet, Francoise; Hindricks, Gerd; Juul-Moeller, Steen; Kaeaeb, Stefan; Kappenberger, Lukas; Kespohl, Stefanie; Kotecha, Dipak; Lane, Deirdre A.; Leute, Angelika; Lewalter, Thorsten; Meyer, Ralf; Mont, Lluis; Muenzel, Felix; Nabauer, Michael; Nielsen, Jens C.; Oeff, Michael; Oldgren, Jonas; Oto, Ali; Piccini, Jonathan P.; Pilmeyer, Art; Potpara, Tatjana; Ravens, Ursula; Reinecke, Holger; Rostock, Thomas; Rustige, Joerg; Savelieva, Irene; Schnabel, Renate; Schotten, Ulrich; Schwichtenberg, Lars; Sinner, Moritz F.; Steinbeck, Gerhard; Stoll, Monika; Tavazzi, Luigi; Themistoclakis, Sakis; Tse, Hung Fat; Van Gelder, Isabelle C.; Vardas, Panagiotis E.; Varpula, Timo; Vincent, Alphons; Werring, David; Willems, Stephan; Ziegler, Andre; Lip, Gregory Y. H.; Camm, A. John

    2016-01-01

    At least 30 million people worldwide carry a diagnosis of atrial fibrillation (AF), and many more suffer from undiagnosed, subclinical, or 'silent' AF. Atrial fibrillation-related cardiovascular mortality and morbidity, including cardiovascular deaths, heart failure, stroke, and hospitalizations,