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Sample records for human atrial myocardium

  1. 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.

    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

  2. Bile acids induce arrhythmias in human atrial myocardium--implications for altered serum bile acid composition in patients with atrial fibrillation.

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    Rainer, Peter P; Primessnig, Uwe; Harenkamp, Sandra; Doleschal, Bernhard; Wallner, Markus; Fauler, Guenter; Stojakovic, Tatjana; Wachter, Rolf; Yates, Ameli; Groschner, Klaus; Trauner, Michael; Pieske, Burkert M; von Lewinski, Dirk

    2013-11-01

    High bile acid serum concentrations have been implicated in cardiac disease, particularly in arrhythmias. Most data originate from in vitro studies and animal models. We tested the hypotheses that (1) high bile acid concentrations are arrhythmogenic in adult human myocardium, (2) serum bile acid concentrations and composition are altered in patients with atrial fibrillation (AF) and (3) the therapeutically used ursodeoxycholic acid has different effects than other potentially toxic bile acids. Multicellular human atrial preparations ('trabeculae') were exposed to primary bile acids and the incidence of arrhythmic events was assessed. Bile acid concentrations were measured in serum samples from 250 patients and their association with AF and ECG parameters analysed. Additionally, we conducted electrophysiological studies in murine myocytes. Taurocholic acid (TCA) concentration-dependently induced arrhythmias in atrial trabeculae (14/28 at 300 µM TCA, pursodeoxycholic acid did not. Patients with AF had significantly decreased serum levels of ursodeoxycholic acid conjugates and increased levels of non-ursodeoxycholic bile acids. In isolated myocytes, TCA depolarised the resting membrane potential, enhanced Na(+)/Ca(2+) exchanger (NCX) tail current density and induced afterdepolarisations. Inhibition of NCX prevented arrhythmias in atrial trabeculae. High TCA concentrations induce arrhythmias in adult human atria while ursodeoxycholic acid does not. AF is associated with higher serum levels of non-ursodeoxycholic bile acid conjugates and low levels of ursodeoxycholic acid conjugates. These data suggest that higher levels of toxic (arrhythmogenic) and low levels of protective bile acids create a milieu with a decreased arrhythmic threshold and thus may facilitate arrhythmic events.

  3. Analysis of immune cell populations in atrial myocardium of patients with atrial fibrillation or sinus rhythm.

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    Natalia Smorodinova

    Full Text Available Atrial fibrillation (AF is the most common arrhythmia and despite obvious clinical importance remains its pathogenesis only partially explained. A relation between inflammation and AF has been suggested by findings of increased inflammatory markers in AF patients.The goal of this study was to characterize morphologically and functionally CD45-positive inflammatory cell populations in atrial myocardium of patients with AF as compared to sinus rhythm (SR.We examined 46 subjects (19 with AF, and 27 in SR undergoing coronary bypass or valve surgery. Peroperative bioptic samples of the left and the right atrial tissue were examined using immunohistochemistry.The number of CD3+ T-lymphocytes and CD68-KP1+ cells were elevated in the left atrial myocardium of patients with AF compared to those in SR. Immune cell infiltration of LA was related to the rhythm, but not to age, body size, LA size, mitral regurgitation grade, type of surgery, systemic markers of inflammation or presence of diabetes or hypertension. Most of CD68-KP1+ cells corresponded to dendritic cell population based on their morphology and immunoreactivity for DC-SIGN. The numbers of mast cells and CD20+ B-lymphocytes did not differ between AF and SR patients. No foci of inflammation were detected in any sample.An immunohistochemical analysis of samples from patients undergoing open heart surgery showed moderate and site-specific increase of inflammatory cells in the atrial myocardium of patients with AF compared to those in SR, with prevailing population of monocyte-macrophage lineage. These cells and their cytokine products may play a role in atrial remodeling and AF persistence.

  4. Association of Atrial Fibrillation with Morphological and Electrophysiological Changes of the Atrial Myocardium.

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    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.

  5. Effects of hydroxyl radical induced-Injury in atrial versus ventricular myocardium of dog and rabbit

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    Nitisha Hiranandani

    2010-09-01

    Full Text Available Aim: Despite the widespread use of ventricular tissue in the investigation involving hydroxyl-radical (OH* injury, one of the most potent mediators in ischemia-reperfusion injury, little is known about the impact on atrial myocardium. In this study we thus compared the OH*-induced injury response between atrial and right ventricular muscles from both rabbits and dogs under identical experimental conditions. Methods: Small, contracting ventricular and atrial rabbit and dog trabeculae were directly exposed to OH*, and contractile properties were examined and quantified. Results: A brief OH* exposure led to transient rigor like contracture with marked elevation of diastolic tension and depression of developed force. Although the injury response showed similarities between atrial and ventricular myocardium, there were significant differences as well. In rabbit atrial muscles, the development of the contracture and its peak was much faster as compared to ventricular muscles. Also, at the peak of contracture, both rabbit and dog atrial muscles show a lesser degree of contractile dysfunction. Conclusion: These results indicate that both atrial and ventricular muscles develop a rigor like contracture after acute OH*-induced injury, and atrial muscles showed a lesser degree of contractile dysfunction. Comparison of dog versus rabbit tissue shows that the response was similar in magnitude, but slower to develop in dog tissue.

  6. Visualization of atrial myocardium with thallium-201: case report

    International Nuclear Information System (INIS)

    Cowley, M.J.; Coghlan, H.C.; Logic, J.R.

    1977-01-01

    An adult patient evaluated for cyanotic congenital heart disease was found to have pulmonary atresia with intact ventricular septum, hypoplastic right ventricle, and right atrial enlargement. Thallium-201 myocardial imaging before surgical correction showed thallium activity in the right atrium. Following the establishment of a conduit from the right atrium to pulmonary artery, the right-atrial thallium uptake was even more prominent

  7. Characterization of the positive and negative inotropic effects of acetylcholine in the human myocardium

    NARCIS (Netherlands)

    X.Y. Du (Xiaoyi); R.G. Schoemaker (Regien); E. Bos (Egbert); P.R. Saxena (Pramod Ranjan)

    1995-01-01

    textabstractIn the human isolated myocardium, acetylcholine (10−9 to 10−3 M) elicited a biphasic inotropic effect (a decrease in the lower and an increase in the higher concentration range) in atrial and a positive inotropic effect in ventricular trabeculae. However, under conditions of raised

  8. Distinct patterns of constitutive phosphodiesterase activity in mouse sinoatrial node and atrial myocardium.

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    Rui Hua

    Full Text Available Phosphodiesterases (PDEs are critical regulators of cyclic nucleotides in the heart. In ventricular myocytes, the L-type Ca(2+ current (I(Ca,L is a major target of regulation by PDEs, particularly members of the PDE2, PDE3 and PDE4 families. Conversely, much less is known about the roles of PDE2, PDE3 and PDE4 in the regulation of action potential (AP properties and I(Ca,L in the sinoatrial node (SAN and the atrial myocardium, especially in mice. Thus, the purpose of our study was to measure the effects of global PDE inhibition with Isobutyl-1-methylxanthine (IBMX and selective inhibitors of PDE2, PDE3 and PDE4 on AP properties in isolated mouse SAN and right atrial myocytes. We also measured the effects of these inhibitors on I(Ca,L in SAN and atrial myocytes in comparison to ventricular myocytes. Our data demonstrate that IBMX markedly increases spontaneous AP frequency in SAN myocytes and AP duration in atrial myocytes. Spontaneous AP firing in SAN myocytes was also increased by the PDE2 inhibitor erythro-9-[2-hydroxy-3-nonyl] adenine (EHNA, the PDE3 inhibitor milrinone (Mil and the PDE4 inhibitor rolipram (Rol. In contrast, atrial AP duration was increased by EHNA and Rol, but not by Mil. IBMX also potently, and similarly, increased I(Ca,L in SAN, atrial and ventricular myocytes; however, important differences emerged in terms of which inhibitors could modulate I(Ca,L in each myocyte type. Consistent with our AP measurements, EHNA, Mil and Rol each increased I(Ca,L in SAN myocytes. Also, EHNA and Rol, but not Mil, increased atrial I(Ca,L. In complete contrast, no selective PDE inhibitors increased I(Ca,L in ventricular myocytes when given alone. Thus, our data show that the effects of selective PDE2, PDE3 and PDE4 inhibitors are distinct in the different regions of the myocardium indicating important differences in how each PDE family constitutively regulates ion channel function in the SAN, atrial and ventricular myocardium.

  9. Characterization of the functional and anatomical differences in the atrial and ventricular myocardium from three species of elasmobranch fishes

    DEFF Research Database (Denmark)

    Larsen, Julie; Bushnell, Peter; Steffensen, John

    2017-01-01

    We assessed the functional properties in atrial and ventricular myocardium (using isolated cardiac strips) of smooth dogfish (Mustelus canis), clearnose skate (Raja eglanteria), and sandbar shark (Carcharhinus plumbeus) by blocking Ca2+ release from the sarcoplasmic reticulum (SR) with ryanodine...... positive first derivative (i.e., contractility), and increased time to 50 % relaxation in atrial tissue from smooth dogfish at 30 °C. It also increased times to peak force and half relaxation in clearnose skate atrial and ventricular tissue at both temperatures, but only in atrial tissue from sandbar shark...... at 30 °C; indicating that SR involvement in excitation–contraction (EC) coupling is species- and temperature-specific in elasmobranch fishes, as it is in teleost fishes. Atrial and ventricular myocardium from all three species displayed a negative force–frequency relationship, but there was no evidence...

  10. Gene Expression Networks in the Murine Pulmonary Myocardium Provide Insight into the Pathobiology of Atrial Fibrillation

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    Jordan K. Boutilier

    2017-09-01

    Full Text Available The pulmonary myocardium is a muscular coat surrounding the pulmonary and caval veins. Although its definitive physiological function is unknown, it may have a pathological role as the source of ectopic beats initiating atrial fibrillation. How the pulmonary myocardium gains pacemaker function is not clearly defined, although recent evidence indicates that changed transcriptional gene expression networks are at fault. The gene expression profile of this distinct cell type in situ was examined to investigate underlying molecular events that might contribute to atrial fibrillation. Via systems genetics, a whole-lung transcriptome data set from the BXD recombinant inbred mouse resource was analyzed, uncovering a pulmonary cardiomyocyte gene network of 24 transcripts, coordinately regulated by chromosome 1 and 2 loci. Promoter enrichment analysis and interrogation of publicly available ChIP-seq data suggested that transcription of this gene network may be regulated by the concerted activity of NKX2-5, serum response factor, myocyte enhancer factor 2, and also, at a post-transcriptional level, by RNA binding protein motif 20. Gene ontology terms indicate that this gene network overlaps with molecular markers of the stressed heart. Therefore, we propose that perturbed regulation of this gene network might lead to altered calcium handling, myocyte growth, and contractile force contributing to the aberrant electrophysiological properties observed in atrial fibrillation. We reveal novel molecular interactions and pathways representing possible therapeutic targets for atrial fibrillation. In addition, we highlight the utility of recombinant inbred mouse resources in detecting and characterizing gene expression networks of relatively small populations of cells that have a pathological significance.

  11. Ultrastructural alterations of atrial myocardium induced by adriamycin in chronically treated animals.

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    Lambertenghi-Deliliers, G; Zanon, P L; Pozzoli, E F; Bellini, O; Praga, C

    1978-02-28

    The clinical use of adriamycin (AM) is limited by a possible dose-dependent myocardiopathy. Severe lesions of ventricular myocardium widely described by electron microscopy have been correlated to irreversible congestive heart failure. On the other hand, the atrial contractile elements which differ from the ventricular ones because of the presence of the so-called specific granules have rarely been considered. In the work described in this paper, adriamycin was injected into rabbits and mice according to schedules of chronic toxicity. At the end of the treatment the atrial myocells presented diffuse ultrastructural lesions of mitochondria, sarcoplasmic reticulum and myofibrillar bundles. These alterations might be caused by the ribonucleoprotein synthesis inhibition, by a direct drug toxicity or by an energetic crisis due to early mitochondrial lesions. Besides, adriamycin produces a decrease of the specific atrial granules that play a hypothetic role in the metabolism of myocardial cells. However, lack of information about the contents and the exact function of atrial granules does not allow us to conclude that their decrease in treated animals has a pathogenetic significance in myocardiopathy induced by adriamycin.

  12. Abnormal mitochondrial respiration in failed human myocardium.

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    Sharov, V G; Todor, A V; Silverman, N; Goldstein, S; Sabbah, H N

    2000-12-01

    Chronic heart failure (HF) is associated with morphologic abnormalities of cardiac mitochondria including hyperplasia, reduced organelle size and compromised structural integrity. In this study, we examined whether functional abnormalities of mitochondrial respiration are also present in myocardium of patients with advanced HF. Mitochondrial respiration was examined using a Clark electrode in an oxygraph cell containing saponin-skinned muscle bundles obtained from myocardium of failed explanted human hearts due to ischemic (ICM, n=9) or idiopathic dilated (IDC, n=9) cardiomyopathy. Myocardial specimens from five normal donor hearts served as controls (CON). Basal respiratory rate, respiratory rate after addition of the substrates glutamate and malate (V(SUB)), state 3 respiration (after addition of ADP, V(ADP)) and respiration after the addition of atractyloside (V(AT)) were measured in scar-free muscle bundles obtained from the subendocardial (ENDO) and subepicardial (EPI) thirds of the left ventricular (LV) free wall, interventricular septum and right ventricular (RV) free wall. There were no differences in basal and substrate-supported respiration between CON and HF regardless of etiology. V(ADP)was significantly depressed both in ICM and IDC compared to CON in all the regions studied. The respiratory control ratio, V(ADP)/V(AT), was also significantly decreased in HF compared to CON. In both ICM and IDC, V(ADP)was significantly lower in ENDO compared to EPI. The results indicate that mitochondrial respiration is abnormal in the failing human heart. The findings support the concept of low myocardial energy production in HF via oxidative phosphorylation, an abnormality with a potentially impact on global cardiac performance. Copyright 2000 Academic Press.

  13. [Structural and functional changes of myocardium in Chernobyl disaster clean-up workers with atrial fibrillation].

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    Khomaziuk, I M; Habulavichene, Zh M; Khomaziuk, V A

    2011-01-01

    Particularities and clinical importance of the structural and functional changes of myocardium were estimated in Chernobyl disaster clean-up workers with atrial fibrillation (AF). We examined 122 men with AF, which was associated with ischemic heart disease and arterial hypertension. Paroxysmal AF was diagnosed in 42 patients, 80 patients had permanent AE Control group comprised 80 men without AF. Echocardiography and Doppler studies were performed using ultrasound scanner Aloka SSD-630 (Japan). Significant structural and functional changes of the heart were revealed already in paroxysmal AF and became more pronounced in permanent AF. Increased left atrial size, its ratio to left ventricular end diastolic diameter, diastolic dysfunction were important echocardiographic predictors of AF. Heart walls thickening was accompanied by disorders of myocardial relaxation, increase in myocardial mass led to ischemia, and together they promoted overload, dysfunction of atrium and development of AF. Obligatory echocardiographic examination of the Chernobyl disaster clean-up workers with ischemic heart disease and arterial hypertension is necessary for predicting AF early, ordering adequate therapy in proper time and improving prognosis.

  14. Characterization of the positive and negative inotropic effects of acetylcholine in the human myocardium

    OpenAIRE

    Du, Xiaoyi; Schoemaker, Regien; Bos, Egbert; Saxena, Pramod Ranjan

    1995-01-01

    textabstractIn the human isolated myocardium, acetylcholine (10−9 to 10−3 M) elicited a biphasic inotropic effect (a decrease in the lower and an increase in the higher concentration range) in atrial and a positive inotropic effect in ventricular trabeculae. However, under conditions of raised contractility achieved by exposure to noradrenaline (10−5 M), only negative inotropic effects were observed in both atria and ventricles. Atropine (10−6 M), but not propranolol (10−6 M), antagonized bot...

  15. Selective blockade of protein kinase B protects the rat and human myocardium against ischaemic injury

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    Linares-Palomino, José; Husainy, Muhammad A; Lai, Vien K; Dickenson, John M; Galiñanes, Manuel

    2010-01-01

    Protein kinase B (PKB/Akt) plays a critical role in cell survival but the investigation of its involvement has been limited by the lack of specific pharmacological agents. In this study, using novel PKB inhibitors (VIII and XI), we investigated the role of PKB in cardioprotection of the rat and human myocardium, the location of PKB in relation to mitoKATP channels and p38 mitogen-activated protein kinase (p38 MAPK), and whether the manipulation of PKB can overcome the unresponsiveness to protection of the diabetic myocardium. Myocardial slices from rat left ventricle and from the right atrial appendage of patients undergoing elective cardiac surgery were subjected to 90 min ischaemia/120 min reoxygenation at 37°C. Tissue injury was assessed by creatine kinase (CK) released and determination of cell necrosis and apoptosis. The results showed that blockade of PKB activity caused significant reduction of CK release and cell death, a benefit that was as potent as ischaemic preconditioning and could be reproduced by blockade of phosphatidylinositol 3-kinase (PI-3K) with wortmannin and LY 294002. The protection was time dependent with maximal benefit seen when PKB and PI-3K were inhibited before ischaemia or during both ischaemia and reoxygenation. In addition, it was revealed that PKB is located downstream of mitoKATP channels but upstream of p38 MAPK. PKB inhibition induced a similar degree of protection in the human and rat myocardium and, importantly, it reversed the unresponsiveness to protection of the diabetic myocardium. In conclusion, inhibition of PKB plays a critical role in protection of the mammalian myocardium and may represent a clinical target for the reduction of ischaemic injury. PMID:20403980

  16. Fatty acid uptake in normal human myocardium

    International Nuclear Information System (INIS)

    Vyska, K.; Meyer, W.; Stremmel, W.; Notohamiprodjo, G.; Minami, K.; Machulla, H.J.; Gleichmann, U.; Meyer, H.; Koerfer, R.

    1991-01-01

    Fatty acid binding protein has been found in rat aortic endothelial cell membrane. It has been identified to be a 40-kDa protein that corresponds to a 40-kDa fatty acid binding protein with high affinity for a variety of long chain fatty acids isolated from rat heart myocytes. It is proposed that this endothelial membrane fatty acid binding protein might mediate the myocardial uptake of fatty acids. For evaluation of this hypothesis in vivo, influx kinetics of tracer-labeled fatty acids was examined in 15 normal subjects by scintigraphic techniques. Variation of the plasma fatty acid concentration and plasma perfusion rate has been achieved by modulation of nutrition state and exercise conditions. The clinical results suggest that the myocardial fatty acid influx rate is saturable by increasing fatty acid plasma concentration as well as by increasing plasma flow. For analysis of these data, functional relations describing fatty acid transport from plasma into myocardial tissue in the presence and absence of an unstirred layer were developed. The fitting of these relations to experimental data indicate that the free fatty acid influx into myocardial tissue reveals the criteria of a reaction on a capillary surface in the vicinity of flowing plasma but not of a reaction in extravascular space or in an unstirred layer and that the fatty acid influx into normal myocardium is a saturable process that is characterized by the quantity corresponding to the Michaelis-Menten constant, Km, and the maximal velocity, Vmax, 0.24 ± 0.024 mumol/g and 0.37 ± 0.013 mumol/g(g.min), respectively. These data are compatible with a nondiffusional uptake process mediated by the initial interaction of fatty acids with the 40-kDa membrane fatty acid binding protein of cardiac endothelial cells

  17. Release of atrial natriuretic peptide from rat myocardium in vitro: effect of minoxidil-induced hypertrophy.

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    Kinnunen, P.; Taskinen, T.; Leppäluoto, J.; Ruskoaho, H.

    1990-01-01

    1. Ventricular hypertrophy is characterized by stimulation of ventricular synthesis of atrial natriuretic peptide (ANP). To examine the role of ventricular ANP levels in the secretion of ANP into the circulation, atrial and ventricular levels of immunoreactive-ANP (IR-ANP) as well as ANP messenger RNA (mRNA), and the release of IR-ANP from isolated perfused hearts, both before and after atrialectomy, were measured simultaneously in control and minoxidil-treated Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. 2. IR-ANP levels in the ventricles of untreated, 12 month-old SHR with severe ventricular hypertrophy were increased when compared to age-matched WKY rats. Minoxidil treatment for 8 weeks in both strains resulted in a decrease in mean arterial pressure and increases in ventricular weight to body weight ratios, plasma IR-ANP concentrations (in WKY from 133 +/- 20 to 281 +/- 34 pg ml-1, P less than 0.01; in SHR from 184 +/- 38 to 339 +/- 61 pg ml-1, P less than 0.05), and in ventricular IR-ANP contents (in WKY: 53%; in SHR: 41%). A highly significant correlation was found between ventricular IR-ANP content and ventricular weight to body weight ratio (r = 0.59, P less than 0.001, n = 26). 3. When studied in vitro, in isolated perfused heart preparations, the hypertrophied ventricular tissue after atrialectomy secreted more ANP into the perfusate than ventricles of the control hearts; ventricles contributed 28%, 22%, 18% and 15% of the total ANP release to perfusate in the minoxidil-treated SHR, control SHR, minoxidil-treated WKY and control WKY, respectively.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2141796

  18. Reproducibility of P-31 spectroscopic imaging of normal human myocardium

    International Nuclear Information System (INIS)

    Tavares, N.J.; Chew, W.; Auffermann, W.; Higgins, C.B.

    1988-01-01

    To assess reproducibility of P-31 MR spectroscopy of human myocardium, ten normal male volunteers were studied on two separate occasions. Spectra were acquired on a clinical 1.5-T MR imaging unit (Signa, General Electric) using a one-dimensional gated spectroscopic imaging sequence (matrix size, 32 X 256) over 20 minutes. Peaks in the adenosine triphosphate (ATP) region, phosphocreatine (PCR), phosphodiesters (PD), and peaks attributable to 2,3 diphosphoglycerate from blood were observed. Interindividual and intraindividual variability expressed as standard errors of the mean (mean +- SEM) were 1.54 +- 0.04 (variability among subjects) and 0.04 (variability between first and second studies) for PCR/β ATP; 0.97 +- 0.18 and 0.06 for PD/β ATP; and 0.62 +- 0.10 and 0.05 for PD/PCR, respectively. In conclusion, P-31 MR spectroscopy yields consistent and reproducible myocardial spectra that might be useful in the future for the evaluation and monitoring of cardiac disease

  19. Stereoselective handling of perhexiline: implications regarding accumulation within the human myocardium.

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    Chong, Cher-Rin; Drury, Nigel E; Licari, Giovanni; Frenneaux, Michael P; Horowitz, John D; Pagano, Domenico; Sallustio, Benedetta C

    2015-12-01

    Perhexiline is a prophylactic anti-ischaemic agent with weak calcium antagonist effect which has been increasingly utilised in the management of refractory angina. The metabolic clearance of perhexiline is modulated by CYP2D6 metaboliser status and stereoselectivity. The current study sought to (1) determine whether the acute accumulation of perhexiline in the myocardium is stereoselective and (2) investigate the relationship between duration of short-term therapy and the potential stereoselective effects of perhexiline within myocardium. Patients (n = 129) from the active arm of a randomised controlled trial of preoperative perhexiline in cardiac surgery were treated with oral perhexiline for a median of 9 days. Correlates of atrial and ventricular concentrations of enantiomers were sought via univariate followed by multivariate analyses. Myocardial uptake of both (+) and (-) perhexiline was greater in ventricles than in atria, and there was more rapid clearance of (-) than (+) perhexiline. The main determinants of atrial uptake of both (+) and (-) perhexiline were the plasma concentrations [(+) perhexiline: β = -0.256, p = 0.015; (-) perhexiline: β = -0.347, p = 0.001] and patients' age [(+) perhexiline: β = 0.300, p = 0.004; (-) perhexiline: β = 0.288, p = 0.005]. Atrial uptake of (+) enantiomer also varied directly with duration of therapy (β = 0.228, p = 0.025), while atrial uptake of (-) perhexiline varied inversely with simultaneous heart rate (β = -0.240, p = 0.015). (1) Uptake of both perhexiline enantiomers into atrium is greater with advanced age and displays evidence of both saturability and minor stereoselectivity. (2) Atrial uptake of (-) perhexiline may selectively modulate heart rate reduction.

  20. Characterization of the functional and anatomical differences in the atrial and ventricular myocardium from three species of elasmobranch fishes: smooth dogfish (Mustelus canis), sandbar shark (Carcharhinus plumbeus), and clearnose skate (Raja eglanteria).

    Science.gov (United States)

    Larsen, Julie; Bushnell, Peter; Steffensen, John; Pedersen, Morten; Qvortrup, Klaus; Brill, Richard

    2017-02-01

    We assessed the functional properties in atrial and ventricular myocardium (using isolated cardiac strips) of smooth dogfish (Mustelus canis), clearnose skate (Raja eglanteria), and sandbar shark (Carcharhinus plumbeus) by blocking Ca 2+ release from the sarcoplasmic reticulum (SR) with ryanodine and thapsigargin and measuring the resultant changes in contraction-relaxation parameters and the force-frequency relationship at 20 °C and 30 °C. We also examined ultrastructural differences with electron microscopy. In tissues from smooth dogfish, net force (per cross-sectional area) and measures of the speeds of contraction and relaxation were all higher in atrial than ventricular myocardium at both temperatures. Atrial-ventricular differences were evident in the other two species primarily in measures of the rates of contraction and relaxation. Ryanodine-thapsigargin treatment reduced net force and its maximum positive first derivative (i.e., contractility), and increased time to 50 % relaxation in atrial tissue from smooth dogfish at 30 °C. It also increased times to peak force and half relaxation in clearnose skate atrial and ventricular tissue at both temperatures, but only in atrial tissue from sandbar shark at 30 °C; indicating that SR involvement in excitation-contraction (EC) coupling is species- and temperature-specific in elasmobranch fishes, as it is in teleost fishes. Atrial and ventricular myocardium from all three species displayed a negative force-frequency relationship, but there was no evidence that SR involvement in EC coupling was influenced by heart rate. SR was evident in electron micrographs, generally located in proximity to mitochondria and intercalated discs, and to a lesser extent between the myofibrils; with mitochondria being more numerous in ventricular than atrial myocardium in all three species.

  1. Anisotropy of the apparent frequency dependence of backscatter in formalin fixed human myocardium.

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    Hall, C S; Verdonk, E D; Wickline, S A; Perez, J E; Miller, J G

    1997-01-01

    Measurements of the frequency dependence of ultrasonic backscatter are presented for specific angles of insonification for regions of infarcted and noninfarcted human myocardium. A 5-MHz transducer was used to insonify cylindrical cores taken from 7 noninfarcted regions and 12 infarcted regions of the left ventricular free wall of 6 formalin-fixed human hearts explanted because of ischemic cardiomyopathy. The dependence of apparent (uncompensated for diffraction effects and attenuation) backscatter on frequency was approximated by a power-law dependence, magnitude of B(f)2 = afn. Under ideal conditions in a lossless medium, the effect of not compensating for the effects of diffraction and attenuation leads to the value of n to be 2.0 for Rayleigh scatterers while the frequency dependence of the fully compensated backscatter coefficient would be f4. The value of n was determined over the frequency range, 3-7 MHz. Both nonifarcted and infarcted myocardium exhibited anisotropy of the frequency dependence of backscatter, with maxima occurring at angles that were perpendicular to the predominant myofiber direction and minima when parallel to the fibers. Perpendicular insonification yielded results for n of 1.8 +/- 0.1 for noninfarcted myocardium and 1.2 +/- 0.1 for infarcted myocardium while parallel insonification yielded results of 0.4 +/- 0.1 for noninfarcted and 0.0 +/- 0.1 for infarcted myocardium. The functional form of the angle-dependent backscatter is similar for both noninfarcted and infarcted myocardium, although the frequency dependence is clearly different for both tissue states for all angles of insonification. The results of this study indicate that the anisotropy of the frequency dependence of backscatter may play a significant role in ultrasonic imaging and is an important consideration for ultrasonic tissue characterization in myocardium.

  2. A New Class III Antiarrhythmic Drug Niferidil Prolongs Action Potentials in Guinea Pig Atrial Myocardium via Inhibition of Rapid Delayed Rectifier.

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    Abramochkin, Denis V; Kuzmin, Vladislav S; Rosenshtraukh, Leonid V

    2017-12-01

    A new class III antiarrhythmic drug niferidil (RG-2) has been introduced as a highly effective therapy for cases of persistent atrial fibrillation, but ionic mechanisms of its action are poorly understood. In the present study, the effects of niferidil on action potential (AP) waveform and potassium currents responsible for AP repolarization were investigated in guinea pig atrial myocardium. APs were recorded with sharp glass microelectrodes in multicellular atrial preparations. Whole-cell patch-clamp technique was used to measure K + currents in isolated myocytes. In multicellular atrial preparations, 10 -8  M niferidil effectively prolonged APs by 15.2 ± 2.8% at 90% repolarization level. However, even the highest tested concentrations, 10 -6  M and 10 -5  M failed to prolong APs more than 32.5% of control duration. The estimated concentration of niferedil for half-maximal AP prolongation was 1.13 × 10 -8  M. Among the potassium currents responsible for AP repolarization phase, I K1 was found to be almost insensitive to niferidil. However, another inward rectifier, I KACh , was effectively suppressed by micromolar concentrations of niferidil with IC 50  = 9.2 × 10 -6  M. I KATP was much less sensitive to the drug with IC 50  = 2.26 × 10 -4  M. The slow component of delayed rectifier, I Ks , also demonstrated low sensitivity to niferidil-the highest used concentration, 10 -4  M, decreased peak I Ks density to 46.2 ± 5.5% of control. Unlike I Ks , the rapid component of delayed rectifier, I Kr , appeared to be extremely sensitive to niferidil. The IC 50 was 1.26 × 10 -9  M. I Kr measured in ventricular myocytes was found to be less sensitive to niferidil with IC 50  = 3.82 × 10 -8  M. Niferidil prolongs APs in guinea pig atrial myocardium via inhibition of I Kr .

  3. Effects of a new antiarrhythmic drug SS-68 on electrical activity in working atrial and ventricular myocardium of mouse and their ionic mechanisms

    Directory of Open Access Journals (Sweden)

    Saida K. Bogus

    2015-08-01

    Full Text Available SS-68 is a derivative of indole, which demonstrated strong antiarrhythmic effects not associated with significant QT prolongation in dog models of atrial fibrillation. Therefore, SS-68 was proposed as a new antiarrhythmic drug and the present study is the first describing its effects on action potentials (APs configuration and elucidating the ionic mechanisms of these effects. Sharp microelectrodes were used to record APs in isolated preparations of mouse atrial and ventricular myocardium. In both types of myocardium 10−6 M SS-68 produced reduction of AP duration, 3 × 10−6 M failed to alter AP waveform and 10−5 – 3 × 10−5 M prolonged APs. Sensitivity of main ionic currents to SS-68 was determined using whole-cell patch clamp. Transient potassium current Ito was slightly inhibited by SS-68 with IC50 = 1.43 × 10−4 M. IKur was more sensitive with IC50 = 1.84 × 10−5 M. Background inward rectifier showed very low sensitivity to SS-68 – only 10−4 M SS-68 caused significant reduction of IK1. ICaL was significantly inhibited by 10−6M – 3 × 10−5 M SS-68. The IC50 value for the ICaL was 1.84 × 10−6 M. Thus, main ionic currents of mouse cardiomyocytes are inhibited by SS-68 in the following order of potency: ICaL > IKur > Ito > IK1. While lower concentration of SS-68 shorten APs via suppression of ICaL, higher concentrations inhibit K+-currents leading to APs prolongation.

  4. Relevance of Electrical Remodeling in Human Atrial Fibrillation Results of the Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the Atrial Fibrillation Reduction Atrial Pacing Trial Mechanisms of Atrial Fibrillation Study

    NARCIS (Netherlands)

    Healey, Jeff S.; Israel, Carsten W.; Connolly, Stuart J.; Hohnloser, Stefan H.; Nair, Girish M.; Divakaramenon, Syamkumar; Capucci, Alessandro; Van Gelder, Isabelle C.; Lau, Chu-Pak; Gold, Michael R.; Carlson, Mark; Themeles, Ellison; Morillo, Carlos A.

    Background-In animal models of atrial fibrillation (AF), changes in atrial electrophysiological properties are associated with the development of AF. Their relevance to human AF is unclear. Methods and Results-The Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the

  5. Defined Engineered Human Myocardium with Advanced Maturation for Applications in Heart Failure Modelling and Repair

    Science.gov (United States)

    Tiburcy, Malte; Hudson, James E.; Balfanz, Paul; Schlick, Susanne; Meyer, Tim; Liao, Mei-Ling Chang; Levent, Elif; Raad, Farah; Zeidler, Sebastian; Wingender, Edgar; Riegler, Johannes; Wang, Mouer; Gold, Joseph D.; Kehat, Izhak; Wettwer, Erich; Ravens, Ursula; Dierickx, Pieterjan; van Laake, Linda W.; Goumans, Marie Jose; Khadjeh, Sara; Toischer, Karl; Hasenfuss, Gerd; Couture, Larry A.; Unger, Andreas; Linke, Wolfgang A.; Araki, Toshiyuki; Neel, Benjamin; Keller, Gordon; Gepstein, Lior; Wu, Joseph C.; Zimmermann, Wolfram-Hubertus

    2017-01-01

    Background Advancing structural and functional maturation of stem cell-derived cardiomyocytes remains a key challenge for applications in disease modelling, drug screening, and heart repair. Here, we sought to advance cardiomyocyte maturation in engineered human myocardium (EHM) towards an adult phenotype under defined conditions. Methods We systematically investigated cell composition, matrix and media conditions to generate EHM from embryonic and induced pluripotent stem cell-derived cardiomyocytes and fibroblasts with organotypic functionality under serum-free conditions. We employed morphological, functional, and transcriptome analyses to benchmark maturation of EHM. Results EHM demonstrated important structural and functional properties of postnatal myocardium, including: (1) rod-shaped cardiomyocytes with M-bands assembled as a functional syncytium; (2) systolic twitch forces at a similar level as observed in bona fide postnatal myocardium; (3) a positive force-frequency-response; (4) inotropic responses to β-adrenergic stimulation mediated via canonical β1- and β2-adrenoceptor signaling pathways; and (5) evidence for advanced molecular maturation by transcriptome profiling. EHM responded to chronic catecholamine toxicity with contractile dysfunction, cardiomyocyte hypertrophy, cardiomyocyte death, and NT-proBNP release; all are classical hallmarks of heart failure. Additionally, we demonstrate scalability of EHM according to anticipated clinical demands for cardiac repair. Conclusions We provide proof-of-concept for a universally applicable technology for the engineering of macro-scale human myocardium for disease modelling and heart repair from embryonic and induced pluripotent stem cell-derived cardiomyocytes under defined, serum-free conditions. PMID:28167635

  6. Defined Engineered Human Myocardium With Advanced Maturation for Applications in Heart Failure Modeling and Repair.

    Science.gov (United States)

    Tiburcy, Malte; Hudson, James E; Balfanz, Paul; Schlick, Susanne; Meyer, Tim; Chang Liao, Mei-Ling; Levent, Elif; Raad, Farah; Zeidler, Sebastian; Wingender, Edgar; Riegler, Johannes; Wang, Mouer; Gold, Joseph D; Kehat, Izhak; Wettwer, Erich; Ravens, Ursula; Dierickx, Pieterjan; van Laake, Linda W; Goumans, Marie Jose; Khadjeh, Sara; Toischer, Karl; Hasenfuss, Gerd; Couture, Larry A; Unger, Andreas; Linke, Wolfgang A; Araki, Toshiyuki; Neel, Benjamin; Keller, Gordon; Gepstein, Lior; Wu, Joseph C; Zimmermann, Wolfram-Hubertus

    2017-05-09

    Advancing structural and functional maturation of stem cell-derived cardiomyocytes remains a key challenge for applications in disease modeling, drug screening, and heart repair. Here, we sought to advance cardiomyocyte maturation in engineered human myocardium (EHM) toward an adult phenotype under defined conditions. We systematically investigated cell composition, matrix, and media conditions to generate EHM from embryonic and induced pluripotent stem cell-derived cardiomyocytes and fibroblasts with organotypic functionality under serum-free conditions. We used morphological, functional, and transcriptome analyses to benchmark maturation of EHM. EHM demonstrated important structural and functional properties of postnatal myocardium, including: (1) rod-shaped cardiomyocytes with M bands assembled as a functional syncytium; (2) systolic twitch forces at a similar level as observed in bona fide postnatal myocardium; (3) a positive force-frequency response; (4) inotropic responses to β-adrenergic stimulation mediated via canonical β 1 - and β 2 -adrenoceptor signaling pathways; and (5) evidence for advanced molecular maturation by transcriptome profiling. EHM responded to chronic catecholamine toxicity with contractile dysfunction, cardiomyocyte hypertrophy, cardiomyocyte death, and N-terminal pro B-type natriuretic peptide release; all are classical hallmarks of heart failure. In addition, we demonstrate the scalability of EHM according to anticipated clinical demands for cardiac repair. We provide proof-of-concept for a universally applicable technology for the engineering of macroscale human myocardium for disease modeling and heart repair from embryonic and induced pluripotent stem cell-derived cardiomyocytes under defined, serum-free conditions. © 2017 American Heart Association, Inc.

  7. Kinetics of adenylate metabolism in human and rat myocardium

    OpenAIRE

    Tavenier, M.; Skladanowski, A.C.; Abreu, R.A. de; Jong, J.W. de

    1995-01-01

    textabstractPathways producing and converting adenosine have hardly been investigated in human heart, contrasting work in other species. We compared the kinetics of enzymes associated with purine degradation and salvage in human and rat heart cytoplasm assaying for adenosine deaminase, nucleoside phosphorylase, xanthine oxidoreductase, AMP deaminase, AMP- and IMP-specific 5′-nucleotidases, adenosine kinase and hypoxanthine guanine phosphoribosyltransferase (HGPRT). Xanthine oxidoreductase was...

  8. Pre- and post-synaptic sympathetic function in human hibernating myocardium

    Energy Technology Data Exchange (ETDEWEB)

    John, Anna S.; Pepper, John R.; Dreyfus, Gilles D.; Pennell, Dudley J. [Imperial College, Hammersmith Hospital, National Heart and Lung Institute, London (United Kingdom); Mongillo, Marco; Khan, Muhammad T. [Imperial College, Hammersmith Hospital, Medical Research Council Clinical Sciences Centre, London (United Kingdom); Depre, Christophe [University of Medicine and Dentistry New Jersey, Cardiovascular Research Institute, Department of Cell Biology and Molecular Medicine, New Jersey, NJ (United States); University of Medicine and Dentistry New Jersey, Cardiovascular Research Institute, Department of Medicine, New Jersey, NJ (United States); Rimoldi, Ornella E. [Imperial College, Hammersmith Hospital, National Heart and Lung Institute, London (United Kingdom); Imperial College, Hammersmith Hospital, Medical Research Council Clinical Sciences Centre, London (United Kingdom); New York Medical College, Cardiovascular Research Institute, Department of Medicine, Valhalla, NY (United States); Camici, Paolo G. [Imperial College, Hammersmith Hospital, National Heart and Lung Institute, London (United Kingdom); Imperial College, Hammersmith Hospital, Medical Research Council Clinical Sciences Centre, London (United Kingdom)

    2007-12-15

    Impaired pre-synaptic noradrenaline uptake-1 mechanism has been reported in a swine model of hibernating myocardium (HM). To ascertain whether adrenergic neuroeffector abnormalities are present in human HM, we combined functional measurements in vivo using cardiovascular magnetic resonance (CMR) and positron emission tomography (PET) to assess pre- and post-synaptic sympathetic function. Twelve patients with coronary artery disease and chronic left ventricular (LV) dysfunction underwent CMR at baseline and 6 months after bypass for assessment of regional and global LV function and identification of segments with reversible dysfunction. Before surgery, myocardial noradrenaline uptake-1 ([{sup 11}C]meta-hydroxy-ephedrine; HED) and {beta}-adrenoceptor ({beta}-AR) density ([{sup 11}C]CGP-12177) were measured with PET. Patient PET data were compared with those in 18 healthy controls. The volume of distribution (V{sub d}) of HED in HM (47.95{+-}28.05 ml/g) and infarcted myocardium (42.69{+-}25.76 ml/g) was significantly reduced compared with controls (66.09{+-}14.48 ml/g). The V{sub d} of HED in normal myocardium (49.93{+-}20.48 ml/g) of patients was also lower than that in controls and the difference was close to statistical significance (p=0.06). Myocardial {beta}-AR density was significantly lower in HM (5.49{+-}2.35 pmol/g), infarcted (4.82{+-}2.61 pmol/g) and normal (5.86{+-}1.81 pmol/g) segments of patients compared with healthy controls (8.61{+-}1.32 pmol/g). Noradrenaline uptake-1 mechanism and {beta}-AR density are reduced in the myocardium of patients with chronic LV dysfunction and evidence of HM. The increased sympathetic activity to the heart in these patients is a generalised rather than regional phenomenon which is likely to contribute to the remodelling process of the whole LV rather than playing a causative role in HM. (orig.)

  9. Inter-subject variability in human atrial action potential in sinus rhythm versus chronic atrial fibrillation.

    Directory of Open Access Journals (Sweden)

    Carlos Sánchez

    Full Text Available Human atrial electrophysiology exhibits high inter-subject variability in both sinus rhythm (SR and chronic atrial fibrillation (cAF patients. Variability is however rarely investigated in experimental and theoretical electrophysiological studies, thus hampering the understanding of its underlying causes but also its implications in explaining differences in the response to disease and treatment. In our study, we aim at investigating the ability of populations of human atrial cell models to capture the inter-subject variability in action potential (AP recorded in 363 patients both under SR and cAF conditions.Human AP recordings in atrial trabeculae (n = 469 from SR and cAF patients were used to calibrate populations of computational SR and cAF atrial AP models. Three populations of over 2000 sampled models were generated, based on three different human atrial AP models. Experimental calibration selected populations of AP models yielding AP with morphology and duration in range with experimental recordings. Populations using the three original models can mimic variability in experimental AP in both SR and cAF, with median conductance values in SR for most ionic currents deviating less than 30% from their original peak values. All cAF populations show similar variations in G(K1, G(Kur and G(to, consistent with AF-related remodeling as reported in experiments. In all SR and cAF model populations, inter-subject variability in I(K1 and I(NaK underlies variability in APD90, variability in I(Kur, I(CaL and I(NaK modulates variability in APD50 and combined variability in Ito and I(Kur determines variability in APD20. The large variability in human atrial AP triangulation is mostly determined by I(K1 and either I(NaK or I(NaCa depending on the model.Experimentally-calibrated human atrial AP models populations mimic AP variability in SR and cAF patient recordings, and identify potential ionic determinants of inter-subject variability in human atrial AP

  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. Pre- and post-synaptic sympathetic function in human hibernating myocardium

    International Nuclear Information System (INIS)

    John, Anna S.; Pepper, John R.; Dreyfus, Gilles D.; Pennell, Dudley J.; Mongillo, Marco; Khan, Muhammad T.; Depre, Christophe; Rimoldi, Ornella E.; Camici, Paolo G.

    2007-01-01

    Impaired pre-synaptic noradrenaline uptake-1 mechanism has been reported in a swine model of hibernating myocardium (HM). To ascertain whether adrenergic neuroeffector abnormalities are present in human HM, we combined functional measurements in vivo using cardiovascular magnetic resonance (CMR) and positron emission tomography (PET) to assess pre- and post-synaptic sympathetic function. Twelve patients with coronary artery disease and chronic left ventricular (LV) dysfunction underwent CMR at baseline and 6 months after bypass for assessment of regional and global LV function and identification of segments with reversible dysfunction. Before surgery, myocardial noradrenaline uptake-1 ([ 11 C]meta-hydroxy-ephedrine; HED) and β-adrenoceptor (β-AR) density ([ 11 C]CGP-12177) were measured with PET. Patient PET data were compared with those in 18 healthy controls. The volume of distribution (V d ) of HED in HM (47.95±28.05 ml/g) and infarcted myocardium (42.69±25.76 ml/g) was significantly reduced compared with controls (66.09±14.48 ml/g). The V d of HED in normal myocardium (49.93±20.48 ml/g) of patients was also lower than that in controls and the difference was close to statistical significance (p=0.06). Myocardial β-AR density was significantly lower in HM (5.49±2.35 pmol/g), infarcted (4.82±2.61 pmol/g) and normal (5.86±1.81 pmol/g) segments of patients compared with healthy controls (8.61±1.32 pmol/g). Noradrenaline uptake-1 mechanism and β-AR density are reduced in the myocardium of patients with chronic LV dysfunction and evidence of HM. The increased sympathetic activity to the heart in these patients is a generalised rather than regional phenomenon which is likely to contribute to the remodelling process of the whole LV rather than playing a causative role in HM. (orig.)

  12. Automatic detection and classification of human epicardial atrial unipolar electrograms

    International Nuclear Information System (INIS)

    Dubé, B; Vinet, A; Xiong, F; Yin, Y; LeBlanc, A-R; Pagé, P

    2009-01-01

    This paper describes an unsupervised signal processing method applied to three-channel unipolar electrograms recorded from human atria. These were obtained by epicardial wires sutured on the right and left atria after coronary artery bypass surgery. Atrial (A) and ventricular (V) activations had to be detected and identified on each channel, and gathered across the channels when belonging to the same global event. The algorithm was developed and optimized on a training set of 19 recordings of 5 min. It was assessed on twenty-seven 2 h recordings taken just before the onset of a prolonged atrial fibrillation for a total of 1593697 activations that were validated and classified as normal atrial or ventricular activations (A, V) and premature atrial or ventricular activations (PAA, PVA). 99.93% of the activations were detected, and amongst these, 99.89% of the A and 99.75% of the V activations were correctly labelled. In the subset of the 39705 PAA, 99.83% were detected and 99.3% were correctly classified as A. The false positive rate was 0.37%. In conclusion, a reliable fully automatic detection and classification algorithm was developed that can detect and discriminate A and V activations from atrial recordings. It can provide the time series needed to develop a monitoring system aiming to identify dynamic predictors of forthcoming cardiac events such as postoperative atrial fibrillation

  13. Enhanced Electrical Integration of Engineered Human Myocardium via Intramyocardial versus Epicardial Delivery in Infarcted Rat Hearts.

    Directory of Open Access Journals (Sweden)

    Kaytlyn A Gerbin

    Full Text Available Cardiac tissue engineering is a promising approach to provide large-scale tissues for transplantation to regenerate the heart after ischemic injury, however, integration with the host myocardium will be required to achieve electromechanical benefits. To test the ability of engineered heart tissues to electrically integrate with the host, 10 million human embryonic stem cell (hESC-derived cardiomyocytes were used to form either scaffold-free tissue patches implanted on the epicardium or micro-tissue particles (~1000 cells/particle delivered by intramyocardial injection into the left ventricular wall of the ischemia/reperfusion injured athymic rat heart. Results were compared to intramyocardial injection of 10 million dispersed hESC-cardiomyocytes. Graft size was not significantly different between treatment groups and correlated inversely with infarct size. After implantation on the epicardial surface, hESC-cardiac tissue patches were electromechanically active, but they beat slowly and were not electrically coupled to the host at 4 weeks based on ex vivo fluorescent imaging of their graft-autonomous GCaMP3 calcium reporter. Histologically, scar tissue physically separated the patch graft and host myocardium. In contrast, following intramyocardial injection of micro-tissue particles and suspended cardiomyocytes, 100% of the grafts detected by fluorescent GCaMP3 imaging were electrically coupled to the host heart at spontaneous rate and could follow host pacing up to a maximum of 300-390 beats per minute (5-6.5 Hz. Gap junctions between intramyocardial graft and host tissue were identified histologically. The extensive coupling and rapid response rate of the human myocardial grafts after intramyocardial delivery suggest electrophysiological adaptation of hESC-derived cardiomyocytes to the rat heart's pacemaking activity. These data support the use of the rat model for studying electromechanical integration of human cardiomyocytes, and they

  14. Direct Proof of Endo-Epicardial Asynchrony of the Atrial Wall During Atrial Fibrillation in Humans.

    Science.gov (United States)

    de Groot, Natasja; van der Does, Lisette; Yaksh, Ameeta; Lanters, Eva; Teuwen, Christophe; Knops, Paul; van de Woestijne, Pieter; Bekkers, Jos; Kik, Charles; Bogers, Ad; Allessie, Maurits

    2016-05-01

    The presence of focal fibrillation waves during atrial fibrillation (AF) can, besides ectopic activity, also be explained by asynchronous activation of the atrial endo- and epicardial layer and transmurally propagating fibrillation waves. To provide direct proof of endo-epicardial asynchrony, we performed simultaneous high-resolution mapping of the right atrial endo- and epicardial wall during AF in humans. Intraoperative mapping of the endo- and epicardial right atrial wall was performed during (induced) AF in 10 patients with AF (paroxysmal: n=3; persistent: n=4; and longstanding persistent: n=3) and 4 patients without a history of AF. A clamp made of 2 rectangular 8×16 electrode arrays (interelectrode distance 2 mm) was inserted into the incision in the right atrial appendage. Recordings of 10 seconds of AF were analyzed to determine the incidence of asynchronous endo-epicardial activation times (≥15 ms) of opposite electrodes. Asynchronous endo-epicardial activation ranged between 0.9 and 55.9% without preference for either side. Focal waves appeared equally frequent at endocardium and epicardium (11% versus 13%; ITALIC! P=0.18). Using strict criteria for breakthrough (presence of an opposite wave within 4 mm and ≤14 ms before the origin of the focal wave), the majority (65%) of all focal fibrillation waves could be attributed to endo-epicardial excitation. We provided the first evidence for asynchronous activation of the endo-epicardial wall during AF in humans. Endo-epicardial asynchrony may play a major role in the pathophysiology of AF and may offer an explanation why in some patients therapy fails. © 2016 American Heart Association, Inc.

  15. Synchronous In Situ ATPase Activity, Mechanics, and Ca2+ Sensitivity of Human and Porcine Myocardium

    Czech Academy of Sciences Publication Activity Database

    Griffiths, P. J.; Isackson, H.; Pelc, Radek; Redwood, C.S.; Funari, S.S.; Watkins, H.; Ashley, C. C.

    2009-01-01

    Roč. 97, č. 9 (2009), s. 2503-2512 ISSN 0006-3495 R&D Projects: GA MŠk(CZ) LC06063 Grant - others:EC(XE) RII3-CT-2004-506008 Institutional research plan: CEZ:AV0Z50110509 Keywords : myocardium * actomyosin- ATPase * synchrotron-radiation Subject RIV: ED - Physiology Impact factor: 4.390, year: 2009

  16. In silico assessment of genetic variation in KCNA5 reveals multiple mechanisms of human atrial arrhythmogenesis

    DEFF Research Database (Denmark)

    Colman, Michael A; Ni, Haibo; Liang, Bo

    2017-01-01

    and quantify the functional impact of these KCNA5 mutations on atrial electrical activity. A multi-scale model of the human atria was updated to incorporate detailed experimental data on IKur from both wild-type and mutants. The effects of the mutations on human atrial action potential and rate dependence were...... provides new insights into understanding the mechanisms by which mutant IKur contributes to atrial arrhythmias. In addition, as IKur is an atrial-specific channel and a number of IKur-selective blockers have been developed as anti-AF agents, this study also helps to understand some contradictory results...

  17. Atrial remodelling in atrial fibrillation: CaMKII as a nodal proarrhythmic signal

    Science.gov (United States)

    Mesubi, Olurotimi O.; Anderson, Mark E.

    2016-01-01

    CaMKII is a serine–threonine protein kinase that is abundant in myocardium. Emergent evidence suggests that CaMKII may play an important role in promoting atrial fibrillation (AF) by targeting a diverse array of proteins involved in membrane excitability, cell survival, calcium homeostasis, matrix remodelling, inflammation, and metabolism. Furthermore, CaMKII inhibition appears to protect against AF in animal models and correct proarrhythmic, defective intracellular Ca2+ homeostasis in fibrillating human atrial cells. This review considers current concepts and evidence from animal and human studies on the role of CaMKII in AF. PMID:26762270

  18. Remote Ischaemic PrEconditioning of Human Myocardium (RIPE): study protocol for a double-blinded randomised controlled trial.

    Science.gov (United States)

    Deja, Marek A; Wiaderkiewicz, Ryszard; Czekaj, Piotr; Czech, Ewa; Malinowski, Marcin; Machej, Leszek; Węglarzy, Andrzej; Kowalówka, Adam; Piekarska, Magda; Szurlej, Bartosz; Latusek, Tomasz

    2018-01-01

    Remote preconditioning has been shown to be a potent protective phenomenon in many animals. Several studies aimed to demonstrate it was feasible in humans by trying to show its protective effect during cardiac surgery. Of these, some small studies and one larger trial were positive while two other bigger studies showed no effectiveness of remote preconditioning as assessed by levels of postoperatively released cardiac markers. Recently, two large clinical trials also failed to prove the benefit of remote preconditioning in cardiac surgery. No study showed that remote preconditioning actually increases resistance of human myocardium to standardised ischaemic and reperfusion stimulus in experimental settings. In animal studies, remote preconditioning was shown to improve mitochondrial function and structure, but such data on human myocardium are scarce. The aim of the study is to determine whether remote preconditioning protects human myocardium against ischaemia-reperfusion injury in both in vivo and in vitro conditions. The trial is designed as a single-centre, double-blinded, sham-controlled trial of 120 patients. We randomise (1:1) patients referred for coronary artery bypass grafting for stable coronary artery disease to remote preconditioning or "sham" intervention. The remote preconditioning is obtained by three cycles of 5 min inflation and 5 min deflation of a blood pressure cuff on the right arm. Postoperative course including myocardial enzymes profile will be analysed. Moreover, in the in-vitro arm the clinically preconditioned myocardium will be assessed for function, mitochondria structure, and mitochondria-dependent apoptosis. The informed consent of all patients is obtained before enrolment into the study by the investigator. The study conforms to the spirit and the letter of the declaration of Helsinki. In case the effect of remote preconditioning is not measurable in ex-vivo assessment, any future attempt at implementing this phenomenon in clinical

  19. Proteomic analysis identifies mitochondrial metabolic enzymes as major discriminators between different stages of the failing human myocardium

    DEFF Research Database (Denmark)

    Urbonavicius, Sigitas; Wiggers, Henrik; Bøtker, Hans Erik

    2009-01-01

    Our aim was to identify patterns in differentially regulated proteins associated with the progression of chronic heart failure. We specifically studied proteomics in chronic reversibly (RDM) and irreversibly dysfunctional myocardium (IRDM), as well as end-stage failing myocardium (ESFM).......Our aim was to identify patterns in differentially regulated proteins associated with the progression of chronic heart failure. We specifically studied proteomics in chronic reversibly (RDM) and irreversibly dysfunctional myocardium (IRDM), as well as end-stage failing myocardium (ESFM)....

  20. Effects of postshock atrial pacing on atrial defibrillation outcome in the isolated sheep heart

    NARCIS (Netherlands)

    Skanes, A. C.; Gray, R. A.; Zuur, C. L.; Jalife, J.

    1998-01-01

    BACKGROUND: Failed atrial defibrillation shocks are associated with organization of postshock activity and a substantial postshock electrical quiescence. We investigated the ability of a train of pacing stimuli to capture or locally entrain atrial myocardium during the quiescent period after

  1. Distribution of beta-adrenergic receptors in failing human myocardium. Implications for mechanisms of down-regulation

    International Nuclear Information System (INIS)

    Murphree, S.S.; Saffitz, J.E.

    1989-01-01

    The density of beta-adrenergic receptors is reduced in crude membranes prepared from failing human myocardium. We used quantitative autoradiography of radioligand binding sites in intact tissue slices to determine whether the total tissue content of receptors is reduced and to characterize the transmural distribution of receptors in cardiac myocytes and the coronary vasculature in hearts obtained from nine cardiac transplant patients with severe congestive failure. Binding of [125Iodo]cyanopindolol to transmural slices of human myocardium was rapid, saturable, stereoselective, and displaceable by agonists and antagonists with an appropriate rank order of potency. Binding isotherms in four normal and nine failing ventricles showed a significant reduction in the total tissue content of beta-receptors in failing myocardium (38.3 +/- 2.0 fmol/mg protein) compared with normal tissue (52.4 +/- 1.7 fmol/mg protein, p = 0.038). In the normal ventricles, the greatest receptor density was observed autoradiographically in myocytic regions of the subendocardium. Receptor density of the coronary arterioles was approximately 70% of that in adjacent myocytic regions. The density of binding sites in both myocytic regions and arterioles was diminished in all regions of the failing ventricles, but down-regulation was due primarily to a selective reduction of beta-receptors of subendocardial myocytes (63 +/- 5% of subepicardial receptor density vs. 115 +/- 6% in controls, p less than 0.0001). These observations indicate that down-regulation occurs nonuniformly in the transmural distribution and thus is likely not related simply to elevated circulating catecholamine levels

  2. Increased cross-bridge recruitment contributes to transient increase in force generation beyond maximal capacity in human myocardium.

    Science.gov (United States)

    Milani-Nejad, Nima; Chung, Jae-Hoon; Canan, Benjamin D; Fedorov, Vadim V; Whitson, Bryan A; Kilic, Ahmet; Mohler, Peter J; Janssen, Paul M L

    2018-01-01

    Cross-bridge attachment allows force generation to occur, and rate of tension redevelopment (k tr ) is a commonly used index of cross-bridge cycling rate. Tension overshoots have been observed briefly after a slack-restretch k tr maneuver in various species of animal models and humans. In this study, we set out to determine the properties of these overshoots and their possible underlying mechanism. Utilizing human cardiac trabeculae, we have found that tension overshoots are temperature-dependent and that they do not occur at resting states. In addition, we have found that myosin cross-bridge cycle is vital to these overshoots as inhibition of the cycle results in the blunting of the overshoots and the magnitude of the overshoots are dependent on the level of myofilament activation. Lastly, we show that the number of cross-bridges transiently increase during tension overshoots. These findings lead us to conclude that tension overshoots are likely due to a transient enhancement of the recruitment of myosin heads into the cross-bridge cycling, regulated by the myocardium, and with potential physiological significance in determining cardiac output. We show that isolated human myocardium is capable of transiently increasing its maximal force generation capability by increasing cross-bridge recruitment following slack-restretch maneuver. This process can potentially have important implications and significance in cardiac contraction in vivo. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. Pulmonary Vein, Dorsal Atrial Wall and Atrial Septum Abnormalities in Podoplanin Knockout Mice With Disturbed Posterior Heart Field Contribution

    NARCIS (Netherlands)

    Douglas, Yvonne L.; Mahtab, Edris A. F.; Jongbloed, Monique R. M.; Uhrin, Pavel; Zaujec, Jan; Binder, Bernd R.; Schalij, Martin J.; Poelmann, Robert E.; Deruiter, Marco C.; Gittenberger-De Groot, Adriana C.

    The developing sinus venosus myocardium, derived from the posterior heart field, contributes to the atrial septum, the posterior atrial wall, the sino-atrial node, and myocardium lining the pulmonary and cardinal veins, all expressing podoplanin, a coelomic and myocardial marker. . We compared

  5. 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. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Cardiology.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2015-01-01

    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. 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. This study provides novel insights into understanding atrial electro-mechanics illustrating that AFER impairs atrial contraction due to reduced intracellular Ca2+ transients.

  8. Angiotensin converting enzyme 2 activity and human atrial fibrillation: increased plasma angiotensin converting enzyme 2 activity is associated with atrial fibrillation and more advanced left atrial structural remodelling.

    Science.gov (United States)

    Walters, Tomos E; Kalman, Jonathan M; Patel, Sheila K; Mearns, Megan; Velkoska, Elena; Burrell, Louise M

    2017-08-01

    Angiotensin converting enzyme 2 (ACE2) is an integral membrane protein whose main action is to degrade angiotensin II. Plasma ACE2 activity is increased in various cardiovascular diseases. We aimed to determine the relationship between plasma ACE2 activity and human atrial fibrillation (AF), and in particular its relationship to left atrial (LA) structural remodelling. One hundred and three participants from a tertiary arrhythmia centre, including 58 with paroxysmal AF (PAF), 20 with persistent AF (PersAF), and 25 controls, underwent clinical evaluation, echocardiographic analysis, and measurement of plasma ACE2 activity. A subgroup of 20 participants underwent invasive LA electroanatomic mapping. Plasma ACE2 activity levels were increased in AF [control 13.3 (9.5-22.3) pmol/min/mL; PAF 16.9 (9.7-27.3) pmol/min/mL; PersAF 22.8 (13.7-33.4) pmol/min/mL, P = 0.006]. Elevated plasma ACE2 was associated with older age, male gender, hypertension and vascular disease, elevated left ventricular (LV) mass, impaired LV diastolic function and advanced atrial disease (P < 0.05 for all). Independent predictors of elevated plasma ACE2 activity were AF (P = 0.04) and vascular disease (P < 0.01). There was a significant relationship between elevated ACE2 activity and low mean LA bipolar voltage (adjusted R2 = 0.22, P = 0.03), a high proportion of complex fractionated electrograms (R2 = 0.32, P = 0.009) and a long LA activation time (R2 = 0.20, P = 0.04). Plasma ACE2 activity is elevated in human AF. Both AF and vascular disease predict elevated plasma ACE2 activity, and elevated plasma ACE2 is significantly associated with more advanced LA structural remodelling. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

  9. Radioimmunoassay and characterization of atrial natriuretic peptide in human plasma

    International Nuclear Information System (INIS)

    Yandle, T.G.; Espiner, E.A.; Nicholls, M.G.; Duff, H.

    1986-01-01

    A RIA for alpha-human atrial natriuretic peptide (alpha hANP) in plasma was developed and used to study the immunoreactive components secreted by the heart and circulating in peripheral venous plasma. The assay used [125I]diiodotyrosyl-alpha hANP, purified by high pressure liquid chromatography (HPLC), and a C-terminal-specific antiserum purchased from Peninsula Laboratories. Serial dilution curves of coronary sinus plasma samples were parallel with the standard curve, but significant nonparallelism was found in peripheral plasma samples of low immunoreactivity. When plasma was extracted using C-18 Sep-Pak cartridges, serial dilution curves from both coronary sinus and peripheral plasma samples were parallel to the standard curve. Although values for plasma samples assayed before and after extraction agreed closely (r = 0.99; n = 76), immunoreactive ANP in unextracted plasma was consistently greater (70-79 pmol/liter) than in extracts of plasma, suggesting non-specific interference by a component in plasma when assayed without extraction. Mean plasma immunoreactive ANP in 19 normal subjects consuming a normal salt intake was 14 +/- 1 (+/- SE) pmol/liter. In 5 normal men, increasing dietary sodium intake from 10 to 200 mmol sodium/day was associated with a 2-fold increment in ANP levels, and similar changes accompanied acute sodium loading using iv saline. Elevated values were found in patients with congestive heart failure (mean, 58 pmol/liter; range, 0-200; n = 9), chronic renal failure (mean, 118 pmol/liter; range, 30-290; n = 8), and primary aldosteronism (range, 32-90 pmol/liter; n = 3). HPLC and gel chromatographic analysis of the immunoreactive material found in coronary sinus plasma extracts showed that a large amount of the material eluted in the position of alpha hANP

  10. Collateral blood supply to the myocardium at risk in human myocardial infarction: a quantitative postmortem assessment

    NARCIS (Netherlands)

    Piek, J. J.; Becker, A. E.

    1988-01-01

    The relation between the type and size of myocardial infarcts and collateral development was studied in postmortem human hearts with a new approach that allows quantification of vascular beds. The coronary arteries were perfused with radioactive microspheres and were visualized by injecting a

  11. 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

  12. Direct measurements of relaxation times of phosphorus metabolites in the human myocardium

    International Nuclear Information System (INIS)

    Schindler, R.; Krahe, T.; Neubauer, S.; Hillenbrand, H.; Entzeroth, C.; Horn, M.; Lackner, K.; Ertl, G.

    1992-01-01

    The T 1 relaxation times of the phosphorus metabolites in human heart muscle measurable by 31 P-MR spectra were determined in 12 individuals using a 1.5 Tesla system. Several spectra were recorded consecutively with a pulse repetition time of 1.6s to 24 s. The T 1 times of creatine phosphate (CP), of γ-, α-, β-adenosintriphosphate (ATP), 2,3-diphosphoglycerate (2,3-DPG) together with anorganic phosphate) and phosphodiester (PDE) showed mean measurements of 6.1±0.5, 5.4±0.5, 5.0±0.5, 5.8±1.0, 7.6±1.0, and 5.0±1.0s (M±SE). The accuracy of the ISIS technique was tested with a special phantom. T 1 times were also measured in standard solutions (20mM CP, 10mM ATP); CP was 8.7±0.2s and γ-ATP was 9.9±0.7s. Corrections for partially saturated 31 P-MR spectra - at least for CP/ATP ratios - are relatively small. (orig.) [de

  13. 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

    immersion. During WI, central venous pressure (CVP) and left atrial diameter (LAD) increased (P ... is not the single pivotal stimulus for the acute suppression of renin release in response to intravascular volume expansion by water immersion in humans. Haemodilution constitutes a significant and conceivably the principal stimulus for the acute immersion-induced suppression of renin-angiotensin system activity....

  14. 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

  15. 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.

  16. 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.

  17. Deterministic Encapsulation of Human Cardiac Stem Cells in Variable Composition Nanoporous Gel Cocoons To Enhance Therapeutic Repair of Injured Myocardium.

    Science.gov (United States)

    Kanda, Pushpinder; Alarcon, Emilio I; Yeuchyk, Tanya; Parent, Sandrine; de Kemp, Robert A; Variola, Fabio; Courtman, David; Stewart, Duncan J; Davis, Darryl R

    2018-04-20

    Although cocooning explant-derived cardiac stem cells (EDCs) in protective nanoporous gels (NPGs) prior to intramyocardial injection boosts long-term cell retention, the number of EDCs that finally engraft is trivial and unlikely to account for salutary effects on myocardial function and scar size. As such, we investigated the effect of varying the NPG content within capsules to alter the physical properties of cocoons without influencing cocoon dimensions. Increasing NPG concentration enhanced cell migration and viability while improving cell-mediated repair of injured myocardium. Given that the latter occurred with NPG content having no detectable effect on the long-term engraftment of transplanted cells, we found that changing the physical properties of cocoons prompted explant-derived cardiac stem cells to produce greater amounts of cytokines, nanovesicles, and microRNAs that boosted the generation of new blood vessels and new cardiomyocytes. Thus, by altering the physical properties of cocoons by varying NPG content, the paracrine signature of encapsulated cells can be enhanced to promote greater endogenous repair of injured myocardium.

  18. Comparison of Detailed and Simplified Models of Human Atrial Myocytes to Recapitulate Patient Specific Properties.

    Directory of Open Access Journals (Sweden)

    Daniel M Lombardo

    2016-08-01

    Full Text Available Computer studies are often used to study mechanisms of cardiac arrhythmias, including atrial fibrillation (AF. A crucial component in these studies is the electrophysiological model that describes the membrane potential of myocytes. The models vary from detailed, describing numerous ion channels, to simplified, grouping ionic channels into a minimal set of variables. The parameters of these models, however, are determined across different experiments in varied species. Furthermore, a single set of parameters may not describe variations across patients, and models have rarely been shown to recapitulate critical features of AF in a given patient. In this study we develop physiologically accurate computational human atrial models by fitting parameters of a detailed and of a simplified model to clinical data for five patients undergoing ablation therapy. Parameters were simultaneously fitted to action potential (AP morphology, action potential duration (APD restitution and conduction velocity (CV restitution curves in these patients. For both models, our fitting procedure generated parameter sets that accurately reproduced clinical data, but differed markedly from published sets and between patients, emphasizing the need for patient-specific adjustment. Both models produced two-dimensional spiral wave dynamics for that were similar for each patient. These results show that simplified, computationally efficient models are an attractive choice for simulations of human atrial electrophysiology in spatially extended domains. This study motivates the development and validation of patient-specific model-based mechanistic studies to target therapy.

  19. Electro-mechanical dynamics of spiral waves in a discrete 2D model of human atrial tissue.

    Science.gov (United States)

    Brocklehurst, Paul; Ni, Haibo; Zhang, Henggui; Ye, Jianqiao

    2017-01-01

    We investigate the effect of mechano-electrical feedback and atrial fibrillation induced electrical remodelling (AFER) of cellular ion channel properties on the dynamics of spiral waves in a discrete 2D model of human atrial tissue. The tissue electro-mechanics are modelled using the discrete element method (DEM). Millions of bonded DEM particles form a network of coupled atrial cells representing 2D cardiac tissue, allowing simulations of the dynamic behaviour of electrical excitation waves and mechanical contraction in the tissue. In the tissue model, each cell is modelled by nine particles, accounting for the features of individual cellular geometry; and discrete inter-cellular spatial arrangement of cells is also considered. The electro-mechanical model of a human atrial single-cell was constructed by strongly coupling the electrophysiological model of Colman et al. to the mechanical myofilament model of Rice et al., with parameters modified based on experimental data. A stretch-activated channel was incorporated into the model to simulate the mechano-electrical feedback. In order to investigate the effect of mechano-electrical feedback on the dynamics of spiral waves, simulations of spiral waves were conducted in both the electromechanical model and the electrical-only model in normal and AFER conditions, to allow direct comparison of the results between the models. Dynamics of spiral waves were characterized by tracing their tip trajectories, stability, excitation frequencies and meandering range of tip trajectories. It was shown that the developed DEM method provides a stable and efficient model of human atrial tissue with considerations of the intrinsically discrete and anisotropic properties of the atrial tissue, which are challenges to handle in traditional continuum mechanics models. This study provides mechanistic insights into the complex behaviours of spiral waves and the genesis of atrial fibrillation by showing an important role of the mechano

  20. Electro-mechanical dynamics of spiral waves in a discrete 2D model of human atrial tissue.

    Directory of Open Access Journals (Sweden)

    Paul Brocklehurst

    Full Text Available We investigate the effect of mechano-electrical feedback and atrial fibrillation induced electrical remodelling (AFER of cellular ion channel properties on the dynamics of spiral waves in a discrete 2D model of human atrial tissue. The tissue electro-mechanics are modelled using the discrete element method (DEM. Millions of bonded DEM particles form a network of coupled atrial cells representing 2D cardiac tissue, allowing simulations of the dynamic behaviour of electrical excitation waves and mechanical contraction in the tissue. In the tissue model, each cell is modelled by nine particles, accounting for the features of individual cellular geometry; and discrete inter-cellular spatial arrangement of cells is also considered. The electro-mechanical model of a human atrial single-cell was constructed by strongly coupling the electrophysiological model of Colman et al. to the mechanical myofilament model of Rice et al., with parameters modified based on experimental data. A stretch-activated channel was incorporated into the model to simulate the mechano-electrical feedback. In order to investigate the effect of mechano-electrical feedback on the dynamics of spiral waves, simulations of spiral waves were conducted in both the electromechanical model and the electrical-only model in normal and AFER conditions, to allow direct comparison of the results between the models. Dynamics of spiral waves were characterized by tracing their tip trajectories, stability, excitation frequencies and meandering range of tip trajectories. It was shown that the developed DEM method provides a stable and efficient model of human atrial tissue with considerations of the intrinsically discrete and anisotropic properties of the atrial tissue, which are challenges to handle in traditional continuum mechanics models. This study provides mechanistic insights into the complex behaviours of spiral waves and the genesis of atrial fibrillation by showing an important role of

  1. Plasma Amino Acid Abnormalities in Chronic Heart Failure. Mechanisms, Potential Risks and Targets in Human Myocardium Metabolism

    Directory of Open Access Journals (Sweden)

    Roberto Aquilani

    2017-11-01

    Full Text Available The goal of this study was to measure arterial amino acid levels in patients with chronic heart failure (CHF, and relate them to left ventricular function and disease severity. Amino acids (AAs play a crucial role for heart protein-energy metabolism. In heart failure, arterial AAs, which are the major determinant of AA uptake by the myocardium, are rarely measured. Forty-one subjects with clinically stable CHF (New York Heart Association (NYHA class II to IV were analyzed. After overnight fasting, blood samples from the radial artery were taken to measure AA concentrations. Calorie (KcalI, protein-, fat-, carbohydrate-intake, resting energy expenditure (REE, total daily energy expenditure (REE × 1.3, and cardiac right catheterization variables were all measured. Eight matched controls were compared for all measurements, with the exception of cardiac catheterization. Compared with controls, CHF patients had reduced arterial AA levels, of which both their number and reduced rates are related to Heart Failure (HF severity. Arterial aspartic acid correlated with stroke volume index (r = 0.6263; p < 0.0001 and cardiac index (r = 0.4243; p = 0.0028. The value of arterial aspartic acid (µmol/L multiplied by the cardiac index was associated with left ventricular ejection fraction (r = 0.3765; p = 0.0076. All NYHA groups had adequate protein intake (≥1.1 g/kg/day and inadequate calorie intake (KcalI < REE × 1.3 was found only in class IV patients. This study showed that CHF patients had reduced arterial AA levels directly related to clinical disease severity and left ventricular dysfunction.

  2. A new dynamic 3D virtual methodology for teaching the mechanics of atrial septation as seen in the human heart.

    Science.gov (United States)

    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 bibliographic data from recent studies of atrial septal development. On the basis of this synthesis, consensus on the stages of atrial septation as seen in the human heart has been reached by a group of experts in cardiac embryology and pediatric cardiology. This has permitted the preparation of three-dimensional (3D) computer graphic objects for the anatomical components involved in the different stages of normal human atrial septation. We have provided a virtual guide to the process of normal atrial septation, the animation providing an appreciation of the temporal and morphologic events necessary to separate the systemic and pulmonary venous returns. We have shown that our animations of normal human atrial septation increase significantly the teaching of the complex developmental processes involved, and provide a new dynamic for the process of learning.

  3. Pro-arrhythmogenic effects of atrial fibrillation-induced electrical remodelling: insights from the three-dimensional virtual human atria.

    Science.gov (United States)

    Colman, Michael A; Aslanidi, Oleg V; Kharche, Sanjay; Boyett, Mark R; Garratt, Clifford; Hancox, Jules C; Zhang, Henggui

    2013-09-01

    Chronic atrial fibrillation (AF) is associated with structural and electrical remodelling in the atria, which are associated with a high recurrence of AF. Through biophysically detailed computer modelling, this study investigated mechanisms by which AF-induced electrical remodelling promotes and perpetuates AF. A family of Courtemanche-Ramirez-Nattel variant models of human atrial cell action potentials (APs), taking into account of intrinsic atrial electrophysiological properties, was modified to incorporate various experimental data sets on AF-induced changes of major ionic channel currents (ICaL, IKur, Ito, IK1, IKs, INaCa) and on intracellular Ca(2+) handling. The single cell models for control and AF-remodelled conditions were incorporated into multicellular three-dimensional (3D) atrial tissue models. Effects of the AF-induced electrical remodelling were quantified as the changes of AP profile, AP duration (APD) and its dispersion across the atria, and the vulnerability of atrial tissue to the initiation of re-entry. The dynamic behaviour of re-entrant excitation waves in the 3D models was characterised. In our simulations, AF-induced electrical remodelling abbreviated atrial APD non-uniformly across the atria; this resulted in relatively short APDs co-existing with marked regional differences in the APD at junctions of the crista terminalis/pectinate muscle, pulmonary veins/left atrium. As a result, the measured tissue vulnerability to re-entry initiation at these tissue junctions was increased. The AF-induced electrical remodelling also stabilized and accelerated re-entrant excitation waves, leading to rapid and sustained re-entry. Under the AF-remodelled condition, re-entrant scroll waves in the 3D model degenerated into persistent and erratic wavelets, leading to fibrillation. In conclusion, realistic 3D atrial tissue models indicate that AF-induced electrical remodelling produces regionally heterogeneous and shortened APD; these respectively facilitate

  4. Differential regulation of protein phosphatase 1 (PP1) isoforms in human heart failure and atrial fibrillation.

    Science.gov (United States)

    Meyer-Roxlau, Stefanie; Lämmle, Simon; Opitz, Annett; Künzel, Stephan; Joos, Julius P; Neef, Stefan; Sekeres, Karolina; Sossalla, Samuel; Schöndube, Friedrich; Alexiou, Konstantin; Maier, Lars S; Dobrev, Dobromir; Guan, Kaomei; Weber, Silvio; El-Armouche, Ali

    2017-07-01

    Protein phosphatase 1 (PP1) is a key regulator of important cardiac signaling pathways. Dysregulation of PP1 has been heavily implicated in cardiac dysfunctions. Accordingly, pharmacological targeting of PP1 activity is considered for therapeutic intervention in human cardiomyopathies. Recent evidence from animal models implicated previously unrecognized, isoform-specific activities of PP1 in the healthy and diseased heart. Therefore, this study examined the expression of the distinct PP1 isoforms PP1α, β, and γ in human heart failure (HF) and atrial fibrillation (AF) and addressed the consequences of β-adrenoceptor blocker (beta-blocker) therapy for HF patients with reduced ejection fraction on PP1 isoform expression. Using western blot analysis, we found greater abundance of PP1 isoforms α and γ but unaltered PP1β levels in left ventricular myocardial tissues from HF patients as compared to non-failing controls. However, expression of all three PP1 isoforms was higher in atrial appendages from patients with AF compared to patients with sinus rhythm. Moreover, we found that in human failing ventricles, beta-blocker therapy was associated with lower PP1α abundance and activity, as indicated by higher phosphorylation of the PP1α-specific substrate eIF2α. Greater eIF2α phosphorylation is a known repressor of protein translation, and accordingly, we found lower levels of the endoplasmic reticulum (ER) stress marker Grp78 in the very same samples. We propose that isoform-specific targeting of PP1α activity may be a novel and innovative therapeutic strategy for the treatment of human cardiac diseases by reducing ER stress conditions.

  5. Capillary permeability of 99mTc-DTPA and blood flow rate in the human myocardium determined by intracoronary bolus injection and residue detection

    DEFF Research Database (Denmark)

    Svendsen, Jesper Hastrup; Efsen, F; Haunsø, S

    1992-01-01

    .7 ml.(100 g.min)-1 (SD 13.0). Similar values of blood flow rate, capillary extraction fraction and the PS product were determined in 6 patients with localized coronary atheroma without hemodynamically significant coronary artery stenosis (25-50% luminal narrowing). The values for the regional......The aims of the present study were to quantitate blood flow rate and capillary permeability of 99mTc-DTPA in the human myocardium and to assess whether capillary permeability is influenced by the presence of small degree atherosclerotic lesions. Myocardial blood flow rate and capillary permeability......, a mean value of the capillary permeability-surface area (PS) product of 54.0 ml.(100 g.min)-1 (SD 13.0) was determined from a capillary extraction of 55.0% (SD 9.4%) and a regional myocardial plasma flow rate of 74.6 ml.(100 g.min)-1 (SD 6.3) equivalent with a regional myocardial blood flow rate of 121...

  6. 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.

  7. Selective downregulation of mitochondrial electron transport chain activity and increased oxidative stress in human atrial fibrillation.

    Science.gov (United States)

    Emelyanova, Larisa; Ashary, Zain; Cosic, Milanka; Negmadjanov, Ulugbek; Ross, Gracious; Rizvi, Farhan; Olet, Susan; Kress, David; Sra, Jasbir; Tajik, A Jamil; Holmuhamedov, Ekhson L; Shi, Yang; Jahangir, Arshad

    2016-07-01

    Mitochondria are critical for maintaining normal cardiac function, and a deficit in mitochondrial energetics can lead to the development of the substrate that promotes atrial fibrillation (AF) and its progression. However, the link between mitochondrial dysfunction and AF in humans is still not fully defined. The aim of this study was to elucidate differences in the functional activity of mitochondrial oxidative phosphorylation (OXPHOS) complexes and oxidative stress in right atrial tissue from patients without (non-AF) and with AF (AF) who were undergoing open-heart surgery and were not significantly different for age, sex, major comorbidities, and medications. The overall functional activity of the electron transport chain (ETC), NADH:O2 oxidoreductase activity, was reduced by 30% in atrial tissue from AF compared with non-AF patients. This was predominantly due to a selective reduction in complex I (0.06 ± 0.007 vs. 0.09 ± 0.006 nmol·min(-1)·citrate synthase activity(-1), P = 0.02) and II (0.11 ± 0.012 vs. 0.16 ± 0.012 nmol·min(-1)·citrate synthase activity(-1), P = 0.003) functional activity in AF patients. Conversely, complex V activity was significantly increased in AF patients (0.21 ± 0.027 vs. 0.12 ± 0.01 nmol·min(-1)·citrate synthase activity(-1), P = 0.005). In addition, AF patients exhibited a higher oxidative stress with increased production of mitochondrial superoxide (73 ± 17 vs. 11 ± 2 arbitrary units, P = 0.03) and 4-hydroxynonenal level (77.64 ± 30.2 vs. 9.83 ± 2.83 ng·mg(-1) protein, P = 0.048). Our findings suggest that AF is associated with selective downregulation of ETC activity and increased oxidative stress that can contribute to the progression of the substrate for AF. Copyright © 2016 the American Physiological Society.

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

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    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

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

    International Nuclear Information System (INIS)

    Souza, Sandra C.; Chau, Mary D.L.; Yang, Qing; Gauthier, Marie-Soleil; Clairmont, Kevin B.; Wu, Zhidan; Gromada, Jesper; Dole, William P.

    2011-01-01

    Highlights: → Treatment of differentiated human adipocytes with atrial natriuretic peptide (ANP) increased lipolysis and oxygen consumption by activating AMP-activated protein kinase (AMPK). → 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. → ANP enhanced adipocyte mitochondrial oxidative capacity as evidenced by induction of oxidative mitochondrial genes and increase in oxygen consumption. → Exposure of human adipocytes to fatty acids and (TNFα) 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 peroxisome proliferator

  10. Expression and function of Kv1.1 potassium channels in human atria from patients with atrial fibrillation.

    Science.gov (United States)

    Glasscock, Edward; Voigt, Niels; McCauley, Mark D; Sun, Qiang; Li, Na; Chiang, David Y; Zhou, Xiao-Bo; Molina, Cristina E; Thomas, Dierk; Schmidt, Constanze; Skapura, Darlene G; Noebels, Jeffrey L; Dobrev, Dobromir; Wehrens, Xander H T

    2015-09-01

    Voltage-gated Kv1.1 channels encoded by the Kcna1 gene are traditionally regarded as being neural-specific with no known expression or intrinsic functional role in the heart. However, recent studies in mice reveal low-level Kv1.1 expression in heart and cardiac abnormalities associated with Kv1.1-deficiency suggesting that the channel may have a previously unrecognized cardiac role. Therefore, this study tests the hypothesis that Kv1.1 channels are associated with arrhythmogenesis and contribute to intrinsic cardiac function. In intra-atrial burst pacing experiments, Kcna1-null mice exhibited increased susceptibility to atrial fibrillation (AF). The atria of Kcna1-null mice showed minimal Kv1 family ion channel remodeling and fibrosis as measured by qRT-PCR and Masson's trichrome histology, respectively. Using RT-PCR, immunocytochemistry, and immunoblotting, KCNA1 mRNA and protein were detected in isolated mouse cardiomyocytes and human atria for the first time. Patients with chronic AF (cAF) showed no changes in KCNA1 mRNA levels relative to controls; however, they exhibited increases in atrial Kv1.1 protein levels, not seen in paroxysmal AF patients. Patch-clamp recordings of isolated human atrial myocytes revealed significant dendrotoxin-K (DTX-K)-sensitive outward current components that were significantly increased in cAF patients, reflecting a contribution by Kv1.1 channels. The concomitant increases in Kv1.1 protein and DTX-K-sensitive currents in atria of cAF patients suggest that the channel contributes to the pathological mechanisms of persistent AF. These findings provide evidence of an intrinsic cardiac role of Kv1.1 channels and indicate that they may contribute to atrial repolarization and AF susceptibility.

  11. The histology of human right atrial tissue in patients with high-risk Obstructive Sleep Apnea and underlying cardiovascular disease: A pilot study

    Directory of Open Access Journals (Sweden)

    Erik M. van Oosten

    2015-03-01

    Conclusions: In this pilot study there were no observable histological differences in human right atrial tissue from individuals at high- and low-risk for OSA. Further investigation would be required for more definitive results.

  12. Low energy transvenous cardioversion of short duration atrial tachyarrhythmias in humans using a single lead system.

    Science.gov (United States)

    Heisel, A; Jung, J; Fries, R; Stopp, M; Sen, S; Schieffer, H; Ozbek, C

    1997-01-01

    The purpose of this study was to investigate the efficacy and safety of atrial cardioversion using an endocardial single lead system presently used for ventricular defibrillation. The study population consisted of 26 recipients of an ICD in combination with a conventional endocardial single lead system with the proximal spring electrode as anode in the SVC and the distal as cathode in the apex of the RV. Atrial tachyarrhythmias were induced by right atrial burst pacing. If the arrhythmia sustained > 1 minute, biphasic shocks synchronized with the R wave were delivered using the implanted device, beginning with an energy of 4 J. If 4 J failed to terminate the arrhythmia, energy was increased stepwise, if the first shock was successful, a step-down testing was performed after reinduction of atrial tachyarrhythmias. The mean atrial defibrillation threshold was 2.3 +/- 1.2 J (range, 0.5-5 J). A total of 154 shocks were delivered and no adverse effects were observed. The mean defibrillation threshold for atrial flutter was somewhat lower than that for AF (1.8 +/- 1 J vs 2.7 +/- 1.4 J, P = 0.08). There was no correlation between the atrial defibrillation threshold and a history of previously occurring atrial tachyarrhythmias, the kind of the underlying heart disease, a prescription of antiarrhythmic drugs, the dimension of the LA, the LVEF, or the ventricular DFT. Internal atrial cardioversion of short duration atrial tachyarrhythmias using a transvenous single lead system designed for ventricular defibrillation is feasible and safe at low energies, and may have important clinical applications.

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

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    Paul Brocklehurst

    2015-01-01

    Full Text Available 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 Ca2+ 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.

  14. Pathomorphological Changes of the Myocardium in Canine Dilated Cardiomyopathy (DCM

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    Janus Izabela

    2015-04-01

    Full Text Available The study was conducted on ventricular and atrial wall preparations from 11 dogs with clinically diagnosed dilated cardiomyopathy. After fixation, the specimens were stained with haematoxylin and eosin and Masson-Goldner trichrome technique. Parenchymal changes (fibrosis and fatty infiltration, vascular changes (congestion and coronary vessel wall hypertrophy, degenerative changes (loss of striation, changes in cardiomycyte and nuclei structure, and presence of inflammatory infiltrates (mononuclear and polynuclear were estimated. Complex histological changes in both ventricular and atrial muscles were shown. It was not determined whether the processes occurring in the myocardium have a primary character, or are a consequence of developing heart failure. Such issues will be put under further and more detailed examination.

  15. Decline of Phosphotransfer and Substrate Supply Metabolic Circuits Hinders ATP Cycling in Aging Myocardium.

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    Emirhan Nemutlu

    Full Text Available Integration of mitochondria with cytosolic ATP-consuming/ATP-sensing and substrate supply processes is critical for muscle bioenergetics and electrical activity. Whether age-dependent muscle weakness and increased electrical instability depends on perturbations in cellular energetic circuits is unknown. To define energetic remodeling of aged atrial myocardium we tracked dynamics of ATP synthesis-utilization, substrate supply, and phosphotransfer circuits through adenylate kinase (AK, creatine kinase (CK, and glycolytic/glycogenolytic pathways using 18O stable isotope-based phosphometabolomic technology. Samples of intact atrial myocardium from adult and aged rats were subjected to 18O-labeling procedure at resting basal state, and analyzed using the 18O-assisted HPLC-GC/MS technique. Characteristics for aging atria were lower inorganic phosphate Pi[18O], γ-ATP[18O], β-ADP[18O], and creatine phosphate CrP[18O] 18O-labeling rates indicating diminished ATP utilization-synthesis and AK and CK phosphotransfer fluxes. Shift in dynamics of glycolytic phosphotransfer was reflected in the diminished G6P[18O] turnover with relatively constant glycogenolytic flux or G1P[18O] 18O-labeling. Labeling of G3P[18O], an indicator of G3P-shuttle activity and substrate supply to mitochondria, was depressed in aged myocardium. Aged atrial myocardium displayed reduced incorporation of 18O into second (18O2, third (18O3, and fourth (18O4 positions of Pi[18O] and a lower Pi[18O]/γ-ATP[18 O]-labeling ratio, indicating delayed energetic communication and ATP cycling between mitochondria and cellular ATPases. Adrenergic stress alleviated diminished CK flux, AK catalyzed β-ATP turnover and energetic communication in aging atria. Thus, 18O-assisted phosphometabolomics uncovered simultaneous phosphotransfer through AK, CK, and glycolytic pathways and G3P substrate shuttle deficits hindering energetic communication and ATP cycling, which may underlie energetic

  16. Hemodynamic forces regulate developmental patterning of atrial conduction.

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    Michael C Bressan

    Full Text Available Anomalous action potential conduction through the atrial chambers of the heart can lead to severe cardiac arrhythmia. To date, however, little is known regarding the mechanisms that pattern proper atrial conduction during development. Here we demonstrate that atrial muscle functionally diversifies into at least two heterogeneous subtypes, thin-walled myocardium and rapidly conducting muscle bundles, during a developmental window just following cardiac looping. During this process, atrial muscle bundles become enriched for the fast conduction markers Cx40 and Nav1.5, similar to the precursors of the fast conduction Purkinje fiber network located within the trabeculae of the ventricles. In contrast to the ventricular trabeculae, however, atrial muscle bundles display an increased proliferation rate when compared to the surrounding myocardium. Interestingly, mechanical loading of the embryonic atrial muscle resulted in an induction of Cx40, Nav1.5 and the cell cycle marker Cyclin D1, while decreasing atrial pressure via in vivo ligation of the vitelline blood vessels results in decreased atrial conduction velocity. Taken together, these data establish a novel model for atrial conduction patterning, whereby hemodynamic stretch coordinately induces proliferation and fast conduction marker expression, which in turn promotes the formation of large diameter muscle bundles to serve as preferential routes of conduction.

  17. Backscatter and attenuation characterization of ventricular myocardium

    Science.gov (United States)

    Gibson, Allyson Ann

    2009-12-01

    This Dissertation presents quantitative ultrasonic measurements of the myocardium in fetal hearts and adult human hearts with the goal of studying the physics of sound waves incident upon anisotropic and inhomogeneous materials. Ultrasound has been used as a clinical tool to assess heart structure and function for several decades. The clinical usefulness of this noninvasive approach has grown with our understanding of the physical mechanisms underlying the interaction of ultrasonic waves with the myocardium. In this Dissertation, integrated backscatter and attenuation analyses were performed on midgestational fetal hearts to assess potential differences in the left and right ventricular myocardium. The hearts were interrogated using a 50 MHz transducer that enabled finer spatial resolution than could be achieved at more typical clinical frequencies. Ultrasonic data analyses demonstrated different patterns and relative levels of backscatter and attenuation from the myocardium of the left ventricle and the right ventricle. Ultrasonic data of adult human hearts were acquired with a clinical imaging system and quantified by their magnitude and time delay of cyclic variation of myocardial backscatter. The results were analyzing using Bayes Classification and ROC analysis to quantify potential advantages of using a combination of two features of cyclic variation of myocardial backscatter over using only one or the other feature to distinguish between groups of subjects. When the subjects were classified based on hemoglobin A1c, the homeostasis model assessment of insulin resistance, and the ratio of triglyceride to high-density lipoprotein-cholesterol, differences in the magnitude and normalized time delay of cyclic variation of myocardial backscatter were observed. The cyclic variation results also suggested a trend toward a larger area under the ROC curve when information from magnitude and time delay of cyclic variation is combined using Bayes classification than when

  18. 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.

  19. Human atrial natriuretic peptide treatment for acute heart failure: a systematic review of efficacy and mortality.

    Science.gov (United States)

    Kobayashi, Daiki; Yamaguchi, Norihiro; Takahashi, Osamu; Deshpande, Gautam A; Fukui, Tsuguya

    2012-01-01

    The objectives of this study were to assess the effect of human atrial natriuretic peptide (hANP) treatment on physiological parameters and mortality in acute heart failure. The MEDLINE (1966-2009), EMBASE (1980-2009), Cochrane Central Register of Controlled Trials (1991-2009), American College of Physicians Journal Club (1991), Ichushi (Japana Centra Revuo Medicina) (1983-2009), Cinni (NII Scholarly and Academic Information Navigator) (1959-2009), National Diet Library Online Public Access Catalog (1969-2009), Webcat Plus (Japanese National Institute of Informatics) (1986-2009), Medical Online (1947-2009), and JST China (1981-2009) databases were searched for studies that compared the efficacy of hANP and the mortality in patients with acute heart failure with placebo controls. Only randomized controlled trials (RCTs) were included in the study. Out of 347 articles, a total of 4 studies involving 220 patients with acute heart failure fulfilled the predefined inclusion criteria. There were significant differences in the hemodynamic parameters between the hANP and placebo groups, especially in the pulmonary capillary wedge pressure (PCWP) reduction (standard mean difference [SMD] 2.07; 95% confidence interval [CI], 0.34-3.81) and the cardiac index (SMD 1.79; 95% CI, 0.12-3.47). No statistically significant differences in mortality rates were found (relative risk 1.03; 95% CI, 0.27-3.92). In a limited number of studies, hANP appears to improve several hemodynamic parameters, including pulmonary capillary wedge pressure and cardiac index, but not mortality. Further high-quality studies are needed to corroborate these results. Copyright © 2012 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  20. 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.

  1. [Effect of compound danshen dripping pill combined with intravenous transplantation of human umbilical cord blood mononuclear cells on local inflammatory response in the myocardium of rabbits with acute myocardial infarction].

    Science.gov (United States)

    Deng, Liu-xia; Yu, Guo-long; Al, Qi; Yuan, Chun-ju

    2013-11-01

    To investigate effect of Compound Danshen Dripping Pill (CDDP) on the inflammatory response of the myocardium of acute myocardial infarction (AMI) rabbits, to observe the therapeutic effect of CDDP combined intravenous transplantation of human umbilical cord blood mononuclear cells (HUCBMCs) on inflammatory response, pro-inflammatory cytokine tumor necrosis factor alpha (TNF-alpha) , and heart function in the myocardium of AMI rabbits, and to explore the possible protective mechanisms of the combined therapy. The AMI model was successfully established by ligation of the left anterior coronary artery (LAD) in 40 healthy rabbits.Then they were randomly divided into four groups, i.e., the control group, the CDDP group, the transplantation group, and the combined group, 10 in each group. Rabbits in the control group received intravenous injection of 0.5 mL normal saline via ear vein within 24 h after AMI and then intragastric infusion of normal saline at 5 mL per day. Rabbits in the CDDP group received intravenous injection of 0.5 mL normal saline via ear vein within 24 h after AMI and then intragastric infusion of solution obtained by solving 270 mg CDDP in 5 mL normal saline per day. Rabbits in the transplantation group received intravenous injection of 0.5 mL normal saline labeled with green fluorescent protein (GFP) containing 3 x 10(7) of HUCBMCs via ear vein within 24 h after AMI and then intragastric infusion of normal saline at 5 mL per day. Rabbits in the combined group received intravenous injection of 0.5 mL normal saline labeled with GFP containing 3 x 10(7) of HUCBMCs via ear vein within 24 h after AMI and then intragastric infusion of solution obtained by solving 270 mg CDDP in 5 mL normal saline per day. At week 1 and 4 after treatment, cardiac function indices such as left ventricular fractional shorting (LVFS) and left ventricular ejection fraction (LVEF) were performed by echocardiography; the number of transplanted cells in the myocardium was found

  2. Evolution of the Sinus Venosus from Fish to Human

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    Bjarke Jensen

    2014-03-01

    Full Text Available The sinus venosus, the cardiac chamber upstream of the (right atrium, is a severely underinvestigated structure. Yet, its myocardium harbors the cardiac pacemaker in all vertebrates. In human, ectopic pacemaking and subsequent pathologies may originate from sinus venosus-derived myocardium surrounding the coronary sinus and the superior caval vein. In ectothermic vertebrates, i.e., fishes, amphibians and reptiles, the sinus venosus aids atrial filling by contracting prior to the atrium (atria. This is facilitated by the sinuatrial delay of approximately the same duration as the atrioventricular delay, which facilitates atrial filling of the ventricles. In mammals, the sinuatrial delay is lost, and the sinus venosus-derived myocardium persists as an extensive myocardial sheet surrounding the caval veins, which is activated in synchrony with the myocardium of the atria. The caval vein myocardium is hardly of significance in the healthy formed heart, but we suggest that the sinus venosus functions as a chamber during development when cardiac output, heart rate, blood pressure and architecture is much more like that of ectothermic vertebrates. The remodeling of the sinus venosus in mammals may be an adaptation associated with the high heart rates necessary for postnatal endothermy. If so, the endothermic birds should exhibit a similar remodeling as mammals, which remains to be investigated.

  3. The β3 -adrenoceptor agonist mirabegron increases human atrial force through β1 -adrenoceptors: an indirect mechanism?

    Science.gov (United States)

    Mo, Weilan; Michel, Martin C; Lee, Xiang Wen; Kaumann, Alberto J; Molenaar, Peter

    2017-08-01

    Mirabegron has been classified as a β 3 -adrenoceptor agonist approved for overactive bladder syndrome. We investigated possible cardiac effects of mirabegron in the absence or presence of β-adrenoceptor subtype antagonists. In view of its phenylethanolamine structure, we investigated whether mirabegron has indirect sympathomimetic activity by using neuronal uptake blockers. Right atrial trabeculae, from non-failing hearts, were paced and contractile force measured at 37°C. Single concentrations of mirabegron were added in the absence or presence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX), β 3 (L-748,337), β 1 (CGP 20712A), β 2 (ICI 118,551) -adrenoceptor antagonists, neuronal uptake inhibitors desipramine or phenoxybenzamine. Mirabegron significantly increased contractile force in human right atrium (1 μM, 7.6 ± 2.6%, n = 7; 10 μM, 10.2 ± 1.5%, n = 22 compared with (-)-isoprenaline P < 0.05). In the presence of IBMX, mirabegron (10 μM) caused a greater contraction. L-748,337 (100 nM) had no effect on the increase in contractile force caused by mirabegron (10 μM). In contrast, mirabegron (10 μM) reduced contractile force in the presence of CGP 20712A, which was not affected by L-748,337 (100 nM) or ICI 118,551 (50 nM). Mirabegron (10 μM) also reduced contractile force in the presence of desipramine or phenoxybenzamine. Mirabegron increases human atrial force through β 1 - but not β 3 -adrenoceptors. Desipramine and phenoxybenzamine block neuronal uptake and conceivably prevent mirabegron from releasing noradrenaline. A non-specific cardiodepressant effect is not mediated through β 3 (or β 2 )-adrenoceptors, consistent with lack of β 3 -adrenoceptor function on human atrial contractility. © 2017 The British Pharmacological Society.

  4. HYPERTHYROIDISM AND ATRIAL FIBRILLATION

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    I. M. Marusenko

    2017-01-01

    simultaneous existence of frequent focal impulses and circular motions of the excitation wave – the mechanism re-entry. Successful treatment of atrial fibrillation in patients with thyrotoxicosis is possible only when euthyroidism is achieved. In most cases, after the elimination of thyrotoxicosis, a spontaneous restoration of the sinus rhythm is observed. The chances of sinus rhythm restoration are lower in elderly patients with concomitant organic diseases of the myocardium or long-term atrial fibrillation. Moreover, even radically cured thyrotoxicosis leads to deterioration in the life prognosis.

  5. Effect of Pancreatic Hormones on pro-Atrial Natriuretic Peptide in Humans

    DEFF Research Database (Denmark)

    Zois, Nora E.; Terzic, Dijana; Faerch, Kristine

    2017-01-01

    Plasma concentrations of pro-Atrial natriuretic peptide, proANP, are decreased in obesity and diabetes. Decreased proANP concentrations have also been noted after meal intake, and recently, a glucose-mediated regulation of ANP gene expression was reported. Hence, we evaluated the effects of insul...

  6. Myocardium tracking via matching distributions.

    Science.gov (United States)

    Ben Ayed, Ismail; Li, Shuo; Ross, Ian; Islam, Ali

    2009-01-01

    The goal of this study is to investigate automatic myocardium tracking in cardiac Magnetic Resonance (MR) sequences using global distribution matching via level-set curve evolution. Rather than relying on the pixelwise information as in existing approaches, distribution matching compares intensity distributions, and consequently, is well-suited to the myocardium tracking problem. Starting from a manual segmentation of the first frame, two curves are evolved in order to recover the endocardium (inner myocardium boundary) and the epicardium (outer myocardium boundary) in all the frames. For each curve, the evolution equation is sought following the maximization of a functional containing two terms: (1) a distribution matching term measuring the similarity between the non-parametric intensity distributions sampled from inside and outside the curve to the model distributions of the corresponding regions estimated from the previous frame; (2) a gradient term for smoothing the curve and biasing it toward high gradient of intensity. The Bhattacharyya coefficient is used as a similarity measure between distributions. The functional maximization is obtained by the Euler-Lagrange ascent equation of curve evolution, and efficiently implemented via level-set. The performance of the proposed distribution matching was quantitatively evaluated by comparisons with independent manual segmentations approved by an experienced cardiologist. The method was applied to ten 2D mid-cavity MR sequences corresponding to ten different subjects. Although neither shape prior knowledge nor curve coupling were used, quantitative evaluation demonstrated that the results were consistent with manual segmentations. The proposed method compares well with existing methods. The algorithm also yields a satisfying reproducibility. Distribution matching leads to a myocardium tracking which is more flexible and applicable than existing methods because the algorithm uses only the current data, i.e., does not

  7. Tropical diseases of the myocardium: a review

    Directory of Open Access Journals (Sweden)

    Groom ZC

    2017-04-01

    Full Text Available Zoe C Groom,1 Aristotle D Protopapas,2 Vasileios Zochios3,4 1Costello Medical Consulting Limited, Cambridge, 2Department of Surgery, Division of Surgery and Cancer, Imperial College London, London, 3Department of Intensive Care Medicine, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, 4College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK Abstract: Cardiovascular diseases are widely distributed throughout the world. Human parasitic infections are ubiquitous. Tropical parasites are increasingly recognized as causes of cardiovascular diseases. In this review, we address the most frequently reported parasites that directly infect the myocardium, including Trypanosoma cruzi, the protozoal causative agent of American trypanosomiasis (Chagas disease, and Taenia solium, the cestode causative agent of taeniasis and cysticercosis. We also discuss tropical endomyocardial fibrosis, trichinellosis and schistosomiasis. Health systems, attitudes, the perceptions of both patients and physicians as well as socioeconomic factors should all be explored and recognized as crucial factors for improving the control of cardiovascular diseases in the tropics. Clinicians throughout the world must remain aware of imported parasites as potential causes of cardiac diseases. Keywords: cardiomyopathy, Chagas disease, myocardium, parasitic infection, tropical infections

  8. Atrial remodeling and metabolic dysfunction in idiopathic isolated fibrotic atrial cardiomyopathy.

    Science.gov (United States)

    Cui, Chang; Jiang, Xiaohong; Ju, Weizhu; Wang, Jiaxian; Wang, Daowu; Sun, Zheng; Chen, Minglong

    2018-04-26

    Idiopathic isolated fibrotic atrial cardiomyopathy (IIF-ACM) is a novel subtype of cardiomyopathy characterized by atrial fibrosis that does not involve the ventricular myocardium and is associated with significant atrial tachyarrhythmia. The mechanisms underlying its pathogenesis are unknown. Atrium samples were obtained from 3 patients with IIF-ACM via surgical intervention. Control samples were consisted of 3 atrium biopsies from patients with congenital heart disease and normal sinus rhythm, matched for gender, age and basic clinical characteristics. Comparative histology, immunofluorescence staining, electron microscopy and proteomics analyses were carried out to explore the unique pathogenesis of IIF-ACM. IIF-ACM atria displayed disordered myofibrils, profound fibrosis and mitochondrial damages compared to the control atria. Proteomics profiling identified metabolic pathways as the most profound changes in IIF-ACM. Our study suggested that metabolic changes in the atrial myocardium caused mitochondrial oxidative stress and potential cell damage, which further led to atrial fibrosis and myofibril disorganization, the characteristic phenotype of IIF-ACM. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Atrial Fibrillation

    DEFF Research Database (Denmark)

    Staerk, Laila; Sherer, Jason A; Ko, Darae

    2017-01-01

    The past 3 decades have been characterized by an exponential growth in knowledge and advances in the clinical treatment of atrial fibrillation (AF). It is now known that AF genesis requires a vulnerable atrial substrate and that the formation and composition of this substrate may vary depending...... on comorbid conditions, genetics, sex, and other factors. Population-based studies have identified numerous factors that modify the atrial substrate and increase AF susceptibility. To date, genetic studies have reported 17 independent signals for AF at 14 genomic regions. Studies have established...

  10. Atrial Fibrillation: Diagnosis

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: Diagnosis Past Issues / Winter 2015 Table of Contents ... of your body's cells and organs. Read More "Atrial Fibrillation" Articles Atrial Fibrillation / Who Is at Risk for ...

  11. ATRIAL FLUTTER*

    African Journals Online (AJOL)

    1971-01-02

    Jan 2, 1971 ... Athero- sclerotic cardiovascular disease was present in 23 patients, of whom 3 had ... primum defect, atrial flutter was precipitated by cardiac catheterization. ..... Heart J., 70, 505. UNDERSTANDING REACTIVE DEPRESSION*

  12. Atrial fibrillation

    African Journals Online (AJOL)

    ABEOLUGBENGAS

    Mean blood pressures were 126.03± ... optimal. Keywords: Atrial fibrillation, thrombosis, CHADS2 Score, stroke risk, hypertensive heart disease, ... general population and the average age group ... Appendix 1) to stratify the stroke risk and we.

  13. Effects of isoproterenol on myocardium

    International Nuclear Information System (INIS)

    Barker, M.E.; Lieber, J.G.; Budinger, T.F.

    1982-01-01

    In the course of autoradiographic studies designed to localize 14 C-taurine within the cells of the rat myocardium, severe tissue damage was noted after stimulation by very low levels of isoproterenol. This β-adrenergic agonist had previously been shown by others to modulate taurine uptake by what appeared to be a very specific mechanism, but our studies have led to a different mechanism. Within four hours after injection of isoproterenol at all concentrations used, pronounced edema of myocytes in the subendocardium was noted; this was followed by an inflammatory reation and degeneration of mitochondria and myofilaments

  14. Impact of sarcoplasmic reticulum calcium release on calcium dynamics and action potential morphology in human atrial myocytes: a computational study.

    Directory of Open Access Journals (Sweden)

    Jussi T Koivumäki

    Full Text Available Electrophysiological studies of the human heart face the fundamental challenge that experimental data can be acquired only from patients with underlying heart disease. Regarding human atria, there exist sizable gaps in the understanding of the functional role of cellular Ca²+ dynamics, which differ crucially from that of ventricular cells, in the modulation of excitation-contraction coupling. Accordingly, the objective of this study was to develop a mathematical model of the human atrial myocyte that, in addition to the sarcolemmal (SL ion currents, accounts for the heterogeneity of intracellular Ca²+ dynamics emerging from a structurally detailed sarcoplasmic reticulum (SR. Based on the simulation results, our model convincingly reproduces the principal characteristics of Ca²+ dynamics: 1 the biphasic increment during the upstroke of the Ca²+ transient resulting from the delay between the peripheral and central SR Ca²+ release, and 2 the relative contribution of SL Ca²+ current and SR Ca²+ release to the Ca²+ transient. In line with experimental findings, the model also replicates the strong impact of intracellular Ca²+ dynamics on the shape of the action potential. The simulation results suggest that the peripheral SR Ca²+ release sites define the interface between Ca²+ and AP, whereas the central release sites are important for the fire-diffuse-fire propagation of Ca²+ diffusion. Furthermore, our analysis predicts that the modulation of the action potential duration due to increasing heart rate is largely mediated by changes in the intracellular Na+ concentration. Finally, the results indicate that the SR Ca²+ release is a strong modulator of AP duration and, consequently, myocyte refractoriness/excitability. We conclude that the developed model is robust and reproduces many fundamental aspects of the tight coupling between SL ion currents and intracellular Ca²+ signaling. Thus, the model provides a useful framework for future

  15. Evaluating the Atrial Myopathy Underlying Atrial Fibrillation: Identifying the Arrhythmogenic and Thrombogenic Substrate

    Science.gov (United States)

    Goldberger, Jeffrey J.; Arora, Rishi; Green, David; Greenland, Philip; Lee, Daniel C.; Lloyd-Jones, Donald M.; Markl, Michael; Ng, Jason; Shah, Sanjiv J.

    2015-01-01

    Atrial disease or myopathy forms the substrate for atrial fibrillation (AF) and underlies the potential for atrial thrombus formation and subsequent stroke. Current diagnostic approaches in patients with AF focus on identifying clinical predictors with evaluation of left atrial size by echocardiography serving as the sole measure specifically evaluating the atrium. Although the atrial substrate underlying AF is likely developing for years prior to the onset of AF, there is no current evaluation to identify the pre-clinical atrial myopathy. Atrial fibrosis is one component of the atrial substrate that has garnered recent attention based on newer MRI techniques that have been applied to visualize atrial fibrosis in humans with prognostic implications regarding success of treatment. Advanced ECG signal processing, echocardiographic techniques, and MRI imaging of fibrosis and flow provide up-to-date approaches to evaluate the atrial myopathy underlying AF. While thromboembolic risk is currently defined by clinical scores, their predictive value is mediocre. Evaluation of stasis via imaging and biomarkers associated with thrombogenesis may provide enhanced approaches to assess risk for stroke in patients with AF. Better delineation of the atrial myopathy that serves as the substrate for AF and thromboembolic complications might improve treatment outcomes. Furthermore, better delineation of the pathophysiologic mechanisms underlying the development of the atrial substrate for AF, particularly in its earlier stages, could help identify blood and imaging biomarkers that could be useful to assess risk for developing new onset AF and suggest specific pathways that could be targeted for prevention. PMID:26216085

  16. Atrial Natriuretic Peptide Accelerates Human Endothelial Progenitor Cell-Stimulated Cutaneous Wound Healing and Angiogenesis.

    Science.gov (United States)

    Lee, Tae Wook; Kwon, Yang Woo; Park, Gyu Tae; Do, Eun Kyoung; Yoon, Jung Won; Kim, Seung-Chul; Ko, Hyun-Chang; Kim, Moon-Bum; Kim, Jae Ho

    2018-05-26

    Atrial natriuretic peptide (ANP) is a powerful vasodilating peptide secreted by cardiac muscle cells, and endothelial progenitor cells (EPCs) have been reported to stimulate cutaneous wound healing by mediating angiogenesis. To determine whether ANP can promote the EPC-mediated repair of injured tissues, we examined the effects of ANP on the angiogenic properties of EPCs and on cutaneous wound healing. In vitro, ANP treatment enhanced the migration, proliferation, and endothelial tube-forming abilities of EPCs. Furthermore, small interfering RNA-mediated silencing of natriuretic peptide receptor-1, which is a receptor for ANP, abrogated ANP-induced migration, tube formation, and proliferation of EPCs. In a murine cutaneous wound model, administration of either ANP or EPCs had no significant effect on cutaneous wound healing or angiogenesis in vivo, whereas the co-administration of ANP and EPCs synergistically potentiated wound healing and angiogenesis. In addition, ANP promoted the survival and incorporation of transplanted EPCs into newly formed blood vessels in wounds. These results suggest ANP accelerates EPC-mediated cutaneous wound healing by promoting the angiogenic properties and survival of transplanted EPCs. This article is protected by copyright. All rights reserved. © 2018 by the Wound Healing Society.

  17. The alteration of interelemental ratios in myocardium under the congenital heart disease (SRXRF)

    International Nuclear Information System (INIS)

    Trunova, V.A.; Zvereva, V.V.; Okuneva, G.N.; Levicheva, E.N.

    2007-01-01

    It is the myocardium that bears the basic functional loading during heart working, including muscle contractility and enzyme activity. The elemental concentrations in myocardium tissue of heart were determined by SRXRF technique. Our investigation is systematical: the elemental content in each compartment (left and right ventricles, left and right auricles) of hearts of healthy and diseased children (congenital heart diseases, transposition of main vessels (TMV)) was analyzed. The elemental distribution in myocardium of four heart chambers of human fetuses was also analyzed. Following elements were determined: S, Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr. It was revealed that the elemental concentrations in myocardium of both ventricles are almost constant in heart of fetuses and healthy children. The transition from pre-natal study (fetus) to post-natal study is accompanied by the redistribution of chemical elements in myocardium. The higher concentrations of S, Fe, Ca, Sr and Cu in myocardium of children are observed, the content of K, Br, Rb and especially Se is lower than in heart of fetuses. The elemental distribution in myocardium of children TMV is considerably different in comparison with the healthy children: the higher levels of Cu are observed. The content of Se is lower

  18. 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....

  19. 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...

  20. [Atrial fibrillation].

    Science.gov (United States)

    Spinar, J; Vítovec, J

    2003-09-01

    Atrial fibrilation is the most frequent arrhythmia, the occurrence increasing with age and associated diseases. The incidence at the age below 60 years is markedly lower than one per cent, whereas in persons above 80 years of age it exceeds six per cent. The occurrence in patients with heart failure is from 10% (NYHA II) up to 50% (NYHA IV). Atrial fibrillation is classified into that observed for the first time and permanent, respectively, while transient forms include paroxyzmal and persistent atrial fibrillation. The diagnosis is based on ECG recording, while echocardiography is most significant. The therapy includes two basic questions--anticoagulant or anti-aggregation treatment and the control of rhythm or frequency. The anticoagulant therapy should be introduced in all patients, where contraindications are not present, being necessary before every cardioversion, provided atrial fibrillation lasts more than two days. In patients without any heart disease and with a physiological echocardiogram it is possible to administer only anti-aggregation treatment. Cardioversion (the control of rhythm) is recommended to all symptomatic patients, in other cases and especially in older persons the control of frequency is safer and of more advantage. Electrical cardioversion is more effective that a pharmacological treatment, the sinus rhythm is preferably controlled by dofetilid, ibutilid, propafenon and amiodaron. For the control of heart rate beta-blockers, diltiazem, verapamil and digitalis are recommended.

  1. Atrial Fibrillation: Treatment

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: Treatment Past Issues / Winter 2015 Table of Contents Treatment for atrial fibrillation depends on how often you have symptoms, how ...

  2. A sensitive radioimmunoassay of atrial natriuretic peptide in human plasma, using a tracer with an immobilized glycouril agent

    International Nuclear Information System (INIS)

    Rosmalen, F.M.A.; Tan, A.C.I.T.L.; Benraad, T.J.

    1987-01-01

    A highly specific and sensitive radioimmunoassay (RIA) for alpha-human atrial natriuretic peptide (hANP[1-28]) in plasma was developed. The assay used a [ 125 I]monoiodotyrosyl-hANP[1-28] tracer, prepared with an immobilized glycouril agent (Protag) and purified by high pressure liquid chromatography (HPLC), and a highly specific antiserum raised against hANP[1-28], coupled to keyhole limpet haemocyanin, in sheep. Plasma was extracted using C-18 Seppak cartridges. A good parallelism was found after dilution prior to extraction of plasma of patients with congestive heart failure (CHF) or of plasma of healthy subjects. Recovery of hANP[1-28] added to plasma was 96%. The limit of detection was 0.8 pg/tube, intra- and inter-assay variation were 9 and 12%, respectively. Mean plasma ANP values in 25 normal persons with a normal salt intake was 26.0 ± 15.5 (± SD) pg/ml. Plasma levels of 18 subjects (7 normals, 11 CHF) were measured using four different antisera after the extraction step. High correlations were found between the values obtained with these four antisera. (Auth.)

  3. Atrial fibrillation driven by micro-anatomic intramural re-entry revealed by simultaneous sub-epicardial and sub-endocardial optical mapping in explanted human hearts.

    Science.gov (United States)

    Hansen, Brian J; Zhao, Jichao; Csepe, Thomas A; Moore, Brandon T; Li, Ning; Jayne, Laura A; Kalyanasundaram, Anuradha; Lim, Praise; Bratasz, Anna; Powell, Kimerly A; Simonetti, Orlando P; Higgins, Robert S D; Kilic, Ahmet; Mohler, Peter J; Janssen, Paul M L; Weiss, Raul; Hummel, John D; Fedorov, Vadim V

    2015-09-14

    The complex architecture of the human atria may create physical substrates for sustained re-entry to drive atrial fibrillation (AF). The existence of sustained, anatomically defined AF drivers in humans has been challenged partly due to the lack of simultaneous endocardial-epicardial (Endo-Epi) mapping coupled with high-resolution 3D structural imaging. Coronary-perfused human right atria from explanted diseased hearts (n = 8, 43-72 years old) were optically mapped simultaneously by three high-resolution CMOS cameras (two aligned Endo-Epi views (330 µm2 resolution) and one panoramic view). 3D gadolinium-enhanced magnetic resonance imaging (GE-MRI, 80 µm3 resolution) revealed the atrial wall structure varied in thickness (1.0 ± 0.7-6.8 ± 2.4 mm), transmural fiber angle differences, and interstitial fibrosis causing transmural activation delay from 23 ± 11 to 43 ± 22 ms at increased pacing rates. Sustained AF (>90 min) was induced by burst pacing during pinacidil (30-100 µM) perfusion. Dual-sided sub-Endo-sub-Epi optical mapping revealed that AF was driven by spatially and temporally stable intramural re-entry with 107 ± 50 ms cycle length and transmural activation delay of 67 ± 31 ms. Intramural re-entrant drivers were captured primarily by sub-Endo mapping, while sub-Epi mapping visualized re-entry or 'breakthrough' patterns. Re-entrant drivers were anchored on 3D micro-anatomic tracks (15.4 ± 2.2 × 6.0 ± 2.3 mm2, 2.9 ± 0.9 mm depth) formed by atrial musculature characterized by increased transmural fiber angle differences and interstitial fibrosis. Targeted radiofrequency ablation of the tracks verified these re-entries as drivers of AF. Integrated 3D structural-functional mapping of diseased human right atria ex vivo revealed that the complex atrial microstructure caused significant differences between Endo vs. Epi activation during pacing and sustained AF driven by intramural re-entry anchored to fibrosis-insulated atrial bundles. Published on

  4. 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.

  5. Increased susceptibility to atrial fibrillation secondary to atrial fibrosis in transgenic goats expressing transforming growth factor - B1

    Science.gov (United States)

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in people with significant morbidity and mortality. There is a strong association between atrial fibrosis and AF. Transforming growth factor B1 (TGF-B1) is an essential mediator of atrial fibrosis in animal models and human pat...

  6. CO, Pb++ and SO2 effects on L-type calcium channel and action potential in human atrial myocytes. In silico study

    Directory of Open Access Journals (Sweden)

    Diana C. Pachajoa

    2017-09-01

    Full Text Available Exposure to air pollutants like carbon monoxide (CO, lead (Pb++ and sulfur dioxide (SO2 promotes the occurrence of cardiovascular diseases. Experimental studies have shown that CO, Pb++ and SO2 block L-type calcium channels, reducing the calcium current (ICaL and the action potential duration (APD, which favors the initiation of atrial arrhythmias. The goal is to study the effects of CO, Pb++ and SO2 at different concentrations on ICaL and action potential using computational simulation. For this purpose, models of the effects of the air pollutants on the atrial L-type calcium channel were developed and were incorporated into a mathematical model of a human atrial cell. The results suggest that CO, Pb++ and SO2 block the ICaL current in a fraction that increases along with the concentration, generating an APD shortening. These results are consistent with experimental studies. The combined effect of the three air pollutants produced an APD shortening, which is considered to be a pro-arrhythmic effect.

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

    International Nuclear Information System (INIS)

    Clerico, A.; Marastoni, M.; Del Chicca, M.G.; Giannessi, D.; Del Ry, S.; Andreassi, M.G.; Sabatino, L.; Iascone, M.R.; Biagini, A.; Donato, L.

    1995-01-01

    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 α h 1-28 ANP and some hormone metabolites were iodinated with Na 125 I or Na 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 125 I-labelled ANP from nine healthy men. The main ANP kinetic parameters were derived from the disappearance curves of the [ 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

  8. Thermistor guided radiofrequency ablation of atrial insertion sites in patients with accessory pathways.

    Science.gov (United States)

    Tracy, C M; Moore, H J; Solomon, A J; Rodak, D J; Fletcher, R D

    1995-11-01

    Radiofrequency ablation has gained acceptance in the treatment of patients with symptomatic Wolff-Parkinson-White syndrome. The purpose of this study was to characterize the relation between temperature and other electroconductive parameters in patients undergoing atrial insertion accessory pathway ablation utilizing a thermistor equipped catheter. The mean temperature and power at sites of atrial insertion ablation are lower than has been previously associated with creation of radiofrequency lesions in the ventricle. While high cavitary blood flow in the atrium may result in cooling, the thinner atrial tissue may require less energy to achieve adequate heating than ventricular myocardium.

  9. A COUP-TFII Human Embryonic Stem Cell Reporter Line to Identify and Select Atrial Cardiomyocytes

    NARCIS (Netherlands)

    Schwach, Verena; Verkerk, Arie O.; Mol, Mervyn; Monshouwer-Kloots, Jantine J.; Devalla, Harsha D.; Orlova, Valeria V.; Anastassiadis, Konstantinos; Mummery, Christine L.; Davis, Richard P.; Passier, Robert

    2017-01-01

    Reporter cell lines have already proven valuable in identifying, tracking, and purifying cardiac subtypes and progenitors during differentiation of human pluripotent stem cells (hPSCs). We previously showed that chick ovalbumin upstream promoter transcription factor II (COUP-TFII) is highly enriched

  10. Increased expression of mineralocorticoid receptor and 11beta-hydroxysteroid dehydrogenase type 2 in human atria during atrial fibrillation.

    Science.gov (United States)

    De-An, Pei; Li, Li; Zhi-Yun, Xu; Jin-Yu, Huang; Zheng-Ming, Xu; Min, Wang; Qiang, Yao; Shi-Eng, Huang

    2010-01-01

    Atrialfibrillation (AF) is associated with the activation of the renin-angiotensin-aldosterone system in the atria. It is not clear whether the expression of a mineralocorticoid receptor (MR), or 11beta-hydroxysteroid dehydrogenase type 2 (11betaHSD2), conferring aldosterone specificity to the MR, in patients with AF is altered. Patients with AF may be associated with increased expression of MR and 11betaHSD2 in the atria. Atrial tissue samples of 25 patients with rheumatic heart valve disease undergoing a valve replacement operation were examined. A total of 13 patients had chronic persistent AF (>6 mo) and 12 patients had no history of AF. The MR and 11betaHSD2 expression were analyzed at the mRNA and protein level. The localization of MR and 11betaHSD2 in atrial tissue was performed using specific immunohistochemistry staining. The results of real-time quantitative polymerase chain reaction (PCR) showed that AF groups, in comparison with sinus rhythm, had a higher mRNA expression level of MR or 11betaHSD2 (all P atrial tissue were also significantly increased in patients with AF compared with patients with sinus rhythm (P atrial interstitial fibrosis in patients with AF. These findings may have an important impact on the treatment of AF with aldosterone antagonists. Copyright 2010 Wiley Periodicals, Inc.

  11. Stability of rotors and focal sources for human atrial fibrillation: focal impulse and rotor mapping (FIRM) of AF sources and fibrillatory conduction.

    Science.gov (United States)

    Swarup, Vijay; Baykaner, Tina; Rostamian, Armand; Daubert, James P; Hummel, John; Krummen, David E; Trikha, Rishi; Miller, John M; Tomassoni, Gery F; Narayan, Sanjiv M

    2014-12-01

    Several groups report electrical rotors or focal sources that sustain atrial fibrillation (AF) after it has been triggered. However, it is difficult to separate stable from unstable activity in prior studies that examined only seconds of AF. We applied phase-based focal impulse and rotor mapping (FIRM) to study the dynamics of rotors/sources in human AF over prolonged periods of time. We prospectively mapped AF in 260 patients (169 persistent, 61 ± 12 years) at 6 centers in the FIRM registry, using baskets with 64 contact electrodes per atrium. AF was phase mapped (RhythmView, Topera, Menlo Park, CA, USA). AF propagation movies were interpreted by each operator to assess the source stability/dynamics over tens of minutes before ablation. Sources were identified in 258 of 260 of patients (99%), for 2.8 ± 1.4 sources/patient (1.8 ± 1.1 in left, 1.1 ± 0.8 in right atria). While AF sources precessed in stable regions, emanating activity including spiral waves varied from collision/fusion (fibrillatory conduction). Each source lay in stable atrial regions for 4,196 ± 6,360 cycles, with no differences between paroxysmal versus persistent AF (4,290 ± 5,847 vs. 4,150 ± 6,604; P = 0.78), or right versus left atrial sources (P = 0.26). Rotors and focal sources for human AF mapped by FIRM over prolonged time periods precess ("wobble") but remain within stable regions for thousands of cycles. Conversely, emanating activity such as spiral waves disorganize and collide with the fibrillatory milieu, explaining difficulties in using activation mapping or signal processing analyses at fixed electrodes to detect AF rotors. These results provide a rationale for targeted ablation at AF sources rather than fibrillatory spiral waves. © 2014 Wiley Periodicals, Inc.

  12. Healthy aging and myocardium: A complicated process with various effects in cardiac structure and physiology.

    Science.gov (United States)

    Nakou, E S; Parthenakis, F I; Kallergis, E M; Marketou, M E; Nakos, K S; Vardas, P E

    2016-04-15

    It is known that there is an ongoing increase in life expectancy worldwide, especially in the population older than 65years of age. Cardiac aging is characterized by a series of complex pathophysiological changes affecting myocardium at structural, cellular, molecular and functional levels. These changes make the aged myocardium more susceptible to stress, leading to a high prevalence of cardiovascular diseases (heart failure, atrial fibrillation, left ventricular hypertrophy, coronary artery disease) in the elderly population. The aging process is genetically programmed but modified by environmental influences, so that the rate of aging can vary widely among people. We summarized the entire data concerning all the multifactorial changes in aged myocardium and highlighting the recent evidence for the pathophysiological basis of cardiac aging. Keeping an eye on the clinical side, this review will explore the potential implications of the age-related changes in the clinical management and on novel therapeutic strategies potentially deriving from the scientific knowledge currently acquired on cardiac aging process. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Detection of the myocardium ischemia in scintigraphy

    International Nuclear Information System (INIS)

    Faraggi, M.; Pierquet-Ghazzar, N.; Maunoury, C.

    2005-01-01

    The myocardium scintigraphy (SPECT) gives excellent elements of prognosis allowing to select at the best, the patients having a revascularization, and then an angiography examination. It appears complementary of the coronaries tree imaging and should (in theory) be practised in first in an organisation chart of taking over. In the search of practicable myocardium, the PET with 18 FDG, although being competitive, is more and more forsaken to the MRI profit. In retaliation, the PET with 82 Rb with test of pharmacology stimulation could develop in detection of coronaries disease. (N.C.)

  14. Digoxin for atrial fibrillation and atrial flutter

    DEFF Research Database (Denmark)

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

    2018-01-01

    BACKGROUND: During recent years, systematic reviews of observational studies have compared digoxin to no digoxin in patients with atrial fibrillation or atrial flutter, and the results of these reviews suggested that digoxin seems to increase the risk of all-cause mortality regardless...... of concomitant heart failure. Our objective was to assess the benefits and harms of digoxin for atrial fibrillation and atrial flutter based on randomized clinical trials. METHODS: We searched CENTRAL, MEDLINE, Embase, LILACS, SCI-Expanded, BIOSIS for eligible trials comparing digoxin versus placebo......, no intervention, or other medical interventions in patients with atrial fibrillation or atrial flutter in October 2016. Our primary outcomes were all-cause mortality, serious adverse events, and quality of life. Our secondary outcomes were heart failure, stroke, heart rate control, and conversion to sinus rhythm...

  15. Bioprinting 3D microfibrous scaffolds for engineering endothelialized myocardium and heart-on-a-chip

    Science.gov (United States)

    Zhang, Yu Shrike; Arneri, Andrea; Bersini, Simone; Shin, Su-Ryon; Zhu, Kai; Goli-Malekabadi, Zahra; Aleman, Julio; Colosi, Cristina; Busignani, Fabio; Dell'Erba, Valeria; Bishop, Colin; Shupe, Thomas; Demarchi, Danilo; Moretti, Matteo; Rasponi, Marco; Dokmeci, Mehmet Remzi; Atala, Anthony; Khademhosseini, Ali

    2016-01-01

    Engineering cardiac tissues and organ models remains a great challenge due to the hierarchical structure of the native myocardium. The need of integrating blood vessels brings additional complexity, limiting the available approaches that are suitable to produce integrated cardiovascular organoids. In this work we propose a novel hybrid strategy based on 3D bioprinting, to fabricate endothelialized myocardium. Enabled by the use of our composite bioink, endothelial cells directly bioprinted within microfibrous hydrogel scaffolds gradually migrated towards the peripheries of the microfibers to form a layer of confluent endothelium. Together with controlled anisotropy, this 3D endothelial bed was then seeded with cardiomyocytes to generate aligned myocardium capable of spontaneous and synchronous contraction. We further embedded the organoids into a specially designed microfluidic perfusion bioreactor to complete the endothelialized-myocardium-on-a-chip platform for cardiovascular toxicity evaluation. Finally, we demonstrated that such a technique could be translated to human cardiomyocytes derived from induced pluripotent stem cells to construct endothelialized human myocardium. We believe that our method for generation of endothelialized organoids fabricated through an innovative 3D bioprinting technology may find widespread applications in regenerative medicine, drug screening, and potentially disease modeling. PMID:27710832

  16. Bioprinting 3D microfibrous scaffolds for engineering endothelialized myocardium and heart-on-a-chip.

    Science.gov (United States)

    Zhang, Yu Shrike; Arneri, Andrea; Bersini, Simone; Shin, Su-Ryon; Zhu, Kai; Goli-Malekabadi, Zahra; Aleman, Julio; Colosi, Cristina; Busignani, Fabio; Dell'Erba, Valeria; Bishop, Colin; Shupe, Thomas; Demarchi, Danilo; Moretti, Matteo; Rasponi, Marco; Dokmeci, Mehmet Remzi; Atala, Anthony; Khademhosseini, Ali

    2016-12-01

    Engineering cardiac tissues and organ models remains a great challenge due to the hierarchical structure of the native myocardium. The need of integrating blood vessels brings additional complexity, limiting the available approaches that are suitable to produce integrated cardiovascular organoids. In this work we propose a novel hybrid strategy based on 3D bioprinting, to fabricate endothelialized myocardium. Enabled by the use of our composite bioink, endothelial cells directly bioprinted within microfibrous hydrogel scaffolds gradually migrated towards the peripheries of the microfibers to form a layer of confluent endothelium. Together with controlled anisotropy, this 3D endothelial bed was then seeded with cardiomyocytes to generate aligned myocardium capable of spontaneous and synchronous contraction. We further embedded the organoids into a specially designed microfluidic perfusion bioreactor to complete the endothelialized-myocardium-on-a-chip platform for cardiovascular toxicity evaluation. Finally, we demonstrated that such a technique could be translated to human cardiomyocytes derived from induced pluripotent stem cells to construct endothelialized human myocardium. We believe that our method for generation of endothelialized organoids fabricated through an innovative 3D bioprinting technology may find widespread applications in regenerative medicine, drug screening, and potentially disease modeling. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Atrial fibrillation or flutter

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000184.htm Atrial fibrillation or flutter To use the sharing features on this page, please enable JavaScript. Atrial fibrillation or flutter is a common type of abnormal ...

  18. Atrial fibrillation - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000237.htm Atrial fibrillation - discharge To use the sharing features on this ... have been in the hospital because you have atrial fibrillation . This condition occurs when your heart beats faster ...

  19. Atrial Fibrillation - Multiple Languages

    Science.gov (United States)

    ... Are Here: Home → Multiple Languages → All Health Topics → Atrial Fibrillation URL of this page: https://medlineplus.gov/languages/ ... V W XYZ List of All Topics All Atrial Fibrillation - Multiple Languages To use the sharing features on ...

  20. 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

    2017-01-24

    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-C q , 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.

  1. Atrial Fibrillation: Complications

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: Complications Past Issues / Winter 2015 Table of Contents ... has two major complications—stroke and heart failure. Atrial Fibrillation and Stroke Click to enlarge image This illustration ...

  2. Epicardial fat thickness correlates with P-wave duration, left atrial size and decreased left ventricular systolic function in morbid obesity.

    Science.gov (United States)

    Fernandes-Cardoso, A; Santos-Furtado, M; Grindler, J; Ferreira, L A; Andrade, J L; Santo, M A

    2017-08-01

    Epicardial fat (EF) is increased in obesity and has important interactions with atrial and ventricular myocardium. Most of the evidence in this scenario can be confused by the presence of comorbidities such as hypertension, diabetes and dyslipidemia, which are very common in this population. The influence of EF on atrial remodeling and cardiac function demands further investigation on morbidly obese without these comorbidities. We prospectively recruited 20 metabolically healthy morbidly obese and 20 normo-weights controls. The maximum P-wave duration (PWD) was analyzed by 12-lead electrocardiogram. Left atrial diameter (LAD), left ventricular ejection fraction (LVEF) and EF thickness (EFT) were evaluated by two-dimensional echocardiography. The mean of maximum PWD and LAD were significantly larger in the obese group as compared to the control group: 109.55 ± 11.52 ms × 89.38 ± 11.19 ms and 36.12 ± 3.46 mm × 31.45 ± 2.64 mm, (p function. Copyright © 2017 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

  3. A Review of Neurogenic Stunned Myocardium

    OpenAIRE

    Biso, Sylvia; Wongrakpanich, Supakanya; Agrawal, Akanksha; Yadlapati, Sujani; Kishlyansky, Marina; Figueredo, Vincent

    2017-01-01

    Neurologic stunned myocardium (NSM) is a phenomenon where neurologic events give rise to cardiac abnormalities. Neurologic events like stroke and seizures cause sympathetic storm and autonomic dysregulation that result in myocardial injury. The clinical presentation can involve troponin elevation, left ventricular dysfunction, and ECG changes. These findings are similar to Takotsubo cardiomyopathy and acute coronary syndrome. It is difficult to distinguish NSM from acute coronary syndrome bas...

  4. Atrial Na,K-ATPase increase and potassium dysregulation accentuate the risk of postoperative atrial fibrillation

    DEFF Research Database (Denmark)

    Tran, Cao Thach; Schmidt, Thomas Andersen; Christensen, John Brochorst

    2009-01-01

    BACKGROUND: Postoperative atrial fibrillation is a common complication to cardiac surgery. Na,K-ATPase is of major importance for the resting membrane potential and action potential. The purpose of the present study was to evaluate the importance of Na,K-ATPase concentrations in human atrial...... biopsies and plasma potassium concentrations for the development of atrial fibrillation. METHODS: Atrial myocardial biopsies were obtained from 67 patients undergoing open chest cardiac surgery. Na,K-ATPase was quantified using vanadate-facilitated 3H-ouabain binding. Plasma potassium concentration....../g wet weight (n = 33), p = 0.03]. Also with multivariable analysis, 3H-ouabain-binding site concentration was significantly associated with the development of atrial fibrillation. High increase in plasma potassium concentration during the perioperative period and surgery was associated...

  5. 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

  6. 17β-Estradiol-induced interaction of estrogen receptor α and human atrial essential myosin light chain modulates cardiac contractile function.

    Science.gov (United States)

    Duft, Karolin; Schanz, Miriam; Pham, Hang; Abdelwahab, Ahmed; Schriever, Cindy; Kararigas, Georgios; Dworatzek, Elke; Davidson, Mercy M; Regitz-Zagrosek, Vera; Morano, Ingo; Mahmoodzadeh, Shokoufeh

    2017-01-01

    Chronic increased workload of the human heart causes ventricular hypertrophy, re-expression of the atrial essential myosin light chain (hALC-1), and improved contractile function. Although hALC-1 is an important positive inotropic regulator of the human heart, little is known about its regulation. Therefore, we investigated the role of the sex hormone 17β-estradiol (E2) on hALC-1 gene expression, the underlying molecular mechanisms, and the impact of this regulatory process on cardiac contractile function. We showed that E2 attenuated hALC-1 expression in human atrial tissues of both sexes and in human ventricular AC16 cells. E2 induced the nuclear translocation of estrogen receptor alpha (ERα) and hALC-1 in AC16 cells, where they cooperatively regulate the transcriptional activity of hALC-1 gene promoter. E2-activated ERα required the estrogen response element (ERE) motif within the hALC-1 gene promoter to reduce its transcriptional activity (vehicle: 15.55 ± 4.80 vs. E2: 6.51 ± 3.69; ~2 fold). This inhibitory effect was potentiated in the presence of hALC-1 (vehicle: 11.13 ± 3.66 vs. E2: 2.18 ± 1.10; ~5 fold), and thus, hALC-1 acts as a co-repressor of ERα-mediated transcription. Yeast two-hybrid screening of a human heart cDNA library revealed that ERα interacts physically with hALC-1 in the presence of E2. This interaction was confirmed by Co-Immunoprecipitation and immunofluorescence in human atrium. As a further novel effect, we showed that chronic E2-treatment of adult mouse cardiomyocytes overexpressing hALC-1 resulted in reduced cell-shortening amplitude and twitching kinetics of these cells independent of Ca 2+ activation levels. Together, our data showed that the expression of hALC-1 gene is, at least partly, regulated by E2/ERα, while hALC-1 acts as a co-repressor. The inotropic effect of hALC-1 overexpression in cardiomyocytes can be significantly repressed by E2.

  7. Surgery for atrial fibrillation.

    Science.gov (United States)

    Viganò, M; Graffigna, A; Ressia, L; Minzioni, G; Pagani, F; Aiello, M; Gazzoli, F

    1996-01-01

    The mechanisms of atrial fibrillation arc multiple reentry circuits spinning around the atrial surface, and these baffle any attempt to direct surgical interruption. The purpose of this article is to report the surgical experience in the treatment of isolated and concomitant atrial fibrillation at the Cardiac Surgical Institute of the University of Pavia. In cases of atrial fibrillation secondary to mitral/valve disease, surgical isolation of the left atrium at the time of mitral valve surgery can prevent atrial fibrillation from involving the right atrium, which can exert its diastolic pump function on the right ventricle. Left atrial isolation was performed on 205 patients at the time of mitral valve surgery. Atrial partitioning ("maze operation") creates straight and blind atrial alleys so that non-recentry circuits can take place. Five patients underwent this procedure. In eight-cases of atrial fibrillation secondary to atrial septal defect, the adult patients with atrial septal defect and chronic or paroxysmal atrial fibrillation underwent surgical isolation of the right atrium associated which surgical correction of the defect, in order to let sinus rhythm govern the left atrium and the ventricles. "Lone" atrial fibrillation occurs in hearts with no detectable organic disease. Bi-atrial isolation with creation of an atrial septal internodal "corridor" was performed on 14 patients. In cases of atrial fibrillation secondary to mitral valve disease, left atrial isolation was performed on 205 patients at the time of mitral valve surgery with an overall sinus rhythm recovery of 44%. In the same period, sinus rhythm was recovered and persisted in only 19% of 252 patients who underwent mitral valve replacement along (P < 0.001). Sinus rhythm was less likely to recover in patients with right atriomegaly requiring tricuspid valve annuloplasty: 59% vs 84% (P < 0.001). Restoration of the right atrial function raised the cardiac index from 2.25 +/- 0.55 1/min per m2

  8. Organized Atrial Tachycardias after Atrial Fibrillation Ablation

    Science.gov (United States)

    Castrejón-Castrejón, Sergio; Ortega, Marta; Pérez-Silva, Armando; Doiny, David; Estrada, Alejandro; Filgueiras, David; López-Sendón, José L.; Merino, José L.

    2011-01-01

    The efficacy of catheter-based ablation techniques to treat atrial fibrillation is limited not only by recurrences of this arrhythmia but also, and not less importantly, by new-onset organized atrial tachycardias. The incidence of such tachycardias depends on the type and duration of the baseline atrial fibrillation and specially on the ablation technique which was used during the index procedure. It has been repeatedly reported that the more extensive the left atrial surface ablated, the higher the incidence of organized atrial tachycardias. The exact origin of the pathologic substrate of these trachycardias is not fully understood and may result from the interaction between preexistent regions with abnormal electrical properties and the new ones resultant from radiofrequency delivery. From a clinical point of view these atrial tachycardias tend to remit after a variable time but in some cases are responsible for significant symptoms. A precise knowledge of the most frequent types of these arrhythmias, of their mechanisms and components is necessary for a thorough electrophysiologic characterization if a new ablation procedure is required. PMID:21941669

  9. Visualization of right atrial appendix by Thallium-201 myocardial scintigraphy: concise communication

    International Nuclear Information System (INIS)

    Adachi, H.; Torii, Y.; Kamide, T.; Katsume, H.; Ochiai, M.; Ijichi, H.

    1980-01-01

    The atrial myocardium has been barely visible with thallium-201 myocardial scintigraphy. This is probably related to the difference in size, distance from anterior chest wall, and small coronary blood flow of the atrium, compared with the ventricle. We have encountered eight cases of visualization of the right atrial appendix (RAA). The RAA was identified from multiple projections in all cases and sometimes confirmed by radionuclide angiocardiography. Evidence derived from ECG, chest radiographs, and cardiac catheterization, indicated that the most important factor in the visualization might be the displacement of the RAA to a more anterior position

  10. Right atrial isolation associated with atrial septal closure in patients with atrial septal defect and chronic atrial fibrillation.

    Science.gov (United States)

    Minzioni, G; Graffigna, A; Pagani, F; Vigano, M

    1993-12-01

    To restore sinus rhythm in the remaining heart chambers of six adult patients with atrial septal defect and chronic or paroxysmal atrial fibrillation, electrical, right atrial isolation associated with surgical correction of the defect was performed. All but one patient was free from atrial fibrillation without medication 2-25 months after operation. The isolated right atrial appendages showed intrinsic rhythmical activity in five patients and no electrical activity in one. Right atrial isolation is a safe and effective procedure that abolishes atrial fibrillation in patients with arrhythmia after surgical correction of atrial septal defect.

  11. Liposome kinetics in infarcted canine myocardium

    International Nuclear Information System (INIS)

    Caride, V.J.; Twickler, J.; Zaret, B.L.

    1984-01-01

    To study the mechanisms and kinetics of liposome deposition in the region of the experimental myocardial infarction, the myocardial distribution of positive and negative liposomes was determined as a function of regional myocardial blood flow and time after administration. The study was performed in dogs at 1 and 24 h following experimental myocardial infarction. Twenty-four hours after coronary artery occlusion, the initial myocardial distribution of positive and negative liposomes (2 min) is directly proportional to regional myocardial blood flow. With time, there is reduction of the radiotracer associated with negative liposomes from all myocardial regions (p less than 0.01). In contrast, in areas of moderate and severe blood flow reduction, there is progressive accumulation of tracers entrapped or incorporated in positive liposomes. This increment becomes significant in 120 min (p less than 0.005). Similar findings are observed in studies performed 1 h after coronary artery occlusion. Dual-label liposomes [( 3 H]cholesterol and [99mTc]diethylenetriamine pentaacetic acid) were used to study the integrity of liposomes in normal and ischemic myocardium. Significant dissociation of the aqueous and lipid labels of positive liposomes is observed 1 h following coronary artery occlusion. In the 24-h myocardial infarction model, dissociation of the aqueous and lipid labels in ischemic myocardium is also observed. This phenomenon is more pronounced with positive than with negative liposomes (p less than 0.02)

  12. Substrate use in ischemic and reperfused canine myocardium: quantitative considerations

    International Nuclear Information System (INIS)

    Myears, D.W.; Sobel, B.E.; Bergmann, S.R.

    1987-01-01

    The patterns of use of substrate in reperfused myocardium are not yet well elucidated, and their delineation is essential for adequate interpretation of results of analyses performed after positron emission tomography with labeled substrates to differentiate normal from abnormal heart muscle. Accordingly, in open-chest, anesthetized dogs the authors measured glucose and fatty acid utilization in normal, ischemic, and reperfused myocardium and assessed the contributions of metabolism of each substrate to overall oxidative metabolism. Intracoronary [ 3 H]glucose and [ 14 C]palmitate were administered in five control dogs, eight dogs subjected to 1 h of coronary occlusion, and nine dogs subjected to reperfusion after 1 h of ischemia. Regional coronary venous blood samples were assayed sequentially. In reperfused myocardium, utilization of glucose was 103% greater than that in ischemic and 273% greater than in normal myocardium. Utilization of fatty acid during reperfusion, although greater than that in ischemic myocardium, was significantly less than that in normal myocardium despite restoration of flow to 80% of control values. Despite diminished net uptake of fatty acid, oxidation of fatty acid accounted for 63% of total oxygen consumption in reperfused myocardium. These studies indicate that canine myocardium reperfused after 1 h of ischemia exhibits enhanced uptake of glucose and impaired utilization of palmitate. Nevertheless, palmitate continues to comprise the substrate primarily utilized for oxidative metabolism

  13. Atrial Fibrillation and Hyperthyroidism

    Directory of Open Access Journals (Sweden)

    Jayaprasad N

    2005-10-01

    Full Text Available Atrial fibrillation occurs in 10 – 15% of patients with hyperthyroidism. Low serum thyrotropin concentration is an independent risk factor for atrial fibrillation. Thyroid hormone contributes to arrythmogenic activity by altering the electrophysiological characteristics of atrial myocytes by shortening the action potential duration, enhancing automaticity and triggered activity in the pulmonary vein cardio myocytes. Hyperthyroidism results in excess mortality from increased incidence of circulatory diseases and dysrhythmias. Incidence of cerebral embolism is more in hyperthyroid patients with atrial fibrillation, especially in the elderly and anti-coagulation is indicated in them. Treatment of hyperthyroidism results in conversion to sinus rhythm in up to two-third of patients. Beta-blockers reduce left ventricular hypertrophy and atrial and ventricular arrhythmias in patients with hyperthyroidism. Treatment of sub clinical hyperthyroidism is controversial. Optimizing dose of thyroxine treatment in those with replacement therapy and beta-blockers is useful in exogenous subclinical hyperthyroidism.

  14. Persistent atrial fibrillation vs paroxysmal atrial fibrillation: differences in management.

    Science.gov (United States)

    Margulescu, Andrei D; Mont, Lluis

    2017-08-01

    Atrial fibrillation (AF) is the most common human arrhythmia. AF is a progressive disease, initially being nonsustained and induced by trigger activity, and progressing towards persistent AF through alteration of the atrial myocardial substrate. Treatment of AF aims to decrease the risk of stroke and improve the quality of life, by preventing recurrences (rhythm control) or controlling the heart rate during AF (rate control). In the last 20 years, catheter-based and, less frequently, surgical and hybrid ablation techniques have proven more successful compared with drug therapy in achieving rhythm control in patients with AF. However, the efficiency of ablation techniques varies greatly, being highest in paroxysmal and lowest in long-term persistent AF. Areas covered: In this review, we discuss the fundamental differences between paroxysmal and persistent AF and the potential impact of those differences on patient management, emphasizing the available therapeutic strategies to achieve rhythm control. Expert commentary: Treatment to prevent AF recurrences is suboptimal, particularly in patients with persistent AF. Emerging technologies, such as documentation of atrial fibrosis using magnetic resonance imaging and documentation of electrical substrate using advanced electrocardiographic imaging techniques are likely to provide valuable insights about patient-specific tailoring of treatments.

  15. LEFT ATRIAL FUNCTION: MODERN ASSESSMENT METHODS AND CLINICAL SIGNIFICANCE

    Directory of Open Access Journals (Sweden)

    E. N. Pavlyukova

    2017-01-01

    Full Text Available Assessment of the left atrial (LA function is important aspect of comprehensive cardiovascular system estimation. Many cardiac diseases make an impact to LA work either by direct affect on myocardium or hemodynamic condition changing. It is considered, LA and left ventricle diastolic pressure is interrelated, thus without mitral valve disease LA expanding is a sign of LV filling pressure augmentation. Examination of LA size and function by analysis of atrial reservoir, conduit, and booster pump can predict cardiovascular outcomes in patients with cardiomyopathy, ischemic heart disease and valvular heart disease. The last two decades gave new technologies to accurate and comprehensive LA mechanics estimation, in the first place related to tissue Doppler imaging. Atrial strain and strain rate obtained using two-dimensional speckle-tracking echocardiography have proved to be feasible and reproducible techniques to evaluate LA mechanics.In physiological settings, LA is a highly expandable chamber with relatively low pressures. However in the presence of acute and chronic injury, LA wall stretches. LA stretching is a hallmark of structure changing with myocardial fibrosis and has influence on LA strain and strain rate. LA strain estimation could be useful in the prediction of sinus rhythm restoration and maintenance after cardioversion and catheter ablation. Low values of global longitudinal LA strain indicate irreversible LA remodeling and are related to the atrial fibrillation progression from paroxysmal to permanent forms. The most interesting in these circumstances is the potential contribution of echocardiography to thromboembolic risk stratification in atrial fibrillation and invasive procedures such as atrial ablation. Therefore, at present, the main task is to understand the ways of clinical application of data  obtained during the LA study.

  16. A Review of Neurogenic Stunned Myocardium

    Science.gov (United States)

    Wongrakpanich, Supakanya; Agrawal, Akanksha; Yadlapati, Sujani; Kishlyansky, Marina; Figueredo, Vincent

    2017-01-01

    Neurologic stunned myocardium (NSM) is a phenomenon where neurologic events give rise to cardiac abnormalities. Neurologic events like stroke and seizures cause sympathetic storm and autonomic dysregulation that result in myocardial injury. The clinical presentation can involve troponin elevation, left ventricular dysfunction, and ECG changes. These findings are similar to Takotsubo cardiomyopathy and acute coronary syndrome. It is difficult to distinguish NSM from acute coronary syndrome based on clinical presentation alone. Because of this difficulty, a patient with NSM who is at high risk for coronary heart disease may undergo cardiac catheterization to rule out coronary artery disease. The objective of this review of literature is to enhance physician's awareness of NSM and its features to help tailor management according to the patient's clinical profile. PMID:28875040

  17. Neurogenic stunned myocardium following hemorrhagic cerebral contusion

    International Nuclear Information System (INIS)

    Deleu, D.; Miyares, F.; Kettern, M.; Kumar, S.; Hassens, Y.; Salim, K.

    2007-01-01

    Neurogenic stunned myocardium NSM is a well-known complication of subarachnoidal hemorrhage, but has been reported rarely in association with other central nervous system disorders. A case of NSM is described in a patient with hemorrhagic brain contusion associated with cerebral edema. An 18-year-old man was admitted with severe cranial trauma following a car roll-over. Six days after admission, he developed findings suggestive for NSM. The troponin T and creatine kinase-MB level were elevated and echocardiogram showed apical and inferoposterior hypokinesis and diffuse left ventricular akinesis with severely reduced ejection fraction 18%. Invasive measurements confirmed low cardiac output. His cardiac function resolved completely within 6 days after decompressive craniotomy. This case supports the presumed unifying role of the increased intracranial pressure, probably triggering a vigorous sympathetic outflow hyperactivity leading to NSM. (author)

  18. Contribution to the study of thallium 201 myocardium scintigraphy

    International Nuclear Information System (INIS)

    Annweiler, Marc.

    1976-01-01

    In this work a new isotope was tested in the field of myocardium scintigraphy: thallium 201. The different radioisotopes used so far in myocardium scintigraphy are reviewed to begin with. The main biological and physical characteristics of thallium and the scintillation camera used for this work are described next. In our opinion thallium 201 owing to its biological behavior similar to that of potassium and to its physical characteristics, appears as one of the better -if not the best- known tracer suitable for use in myocardium scintigraphy. Its properties are suited to the use of a scintillation camera, which considerably shortens the examination time and thus allows an isotopic exploration of the myocardium from several incidences. The only disadvantage of this cyclotron-produced isotope seems to be its high price which will probably limit its use on a large scale. Fifty thallium 201 myocardium scintigraphs were practised on forty-eight coronary thrombosis patients. From this was established a precise topographic correlation between the electrocardiographic diagnosis and the scintigraph. The two corresponded in 47 cases out of 50. The few disagreements between ECG and scintigraphic results seem to be due either to poor-quality images or to an overall myocardium hypofixation connected with a very extensive necrosis. This means that thallium 201 myocardium scintigraphy is a reliable method of examination in the great majority of cases, giving a direct picture of the heart muscle and its necrotic lesions [fr

  19. Antiarrhythmic properties of atrial pacing.

    Science.gov (United States)

    Kliś, Magdalena; Sławuta, Agnieszka; Gajek, Jacek

    2017-01-01

    Bradycardia, atrial stretch and dilatation, autonomic nervous system disorders, and the presence of triggers such as atrial premature contractions, are factors which predispose a person to paroxysmal AF. Atrial pacing not only eliminates bradycardia but also prevents atrial premature contractions and dispersion of refractoriness, which are a substrate for atrial fibrillation. As the prolonged duration of atrial activation during pacing, especially from locations changing the physiological pattern of this activation (right atrium lateral wall, right atrium appendage), negatively influences both a mechanical and an electrical function of the atria, the atrial pacing site affects an atrial arrhythmogenesis. A conventional atrial lead location in the right atrium appendage causes non-physiological activation propagation, resulting in a prolongation of the activation time of both atria. This location is optimal according to a passive fixation of the atrial lead but the available contemporary active fixation leads could potentially be located in any area of the atrium. There is growing evidence of the benefit of pacing, imitating the physiological propagation of impulses within the atria. It seems that the Bachmann's bundle pacing is the best pacing site within the atria, not only positively influencing the atrial mechanical function but also best fulfilling the so-called atrial resynchronization function, in particular in patients with interatrial conduction delay. It can be effectively achieved using only one atrial electrode, and the slight shortening of atrioventricular conduction provides an additional benefit of this atrial pacing site.

  20. What Is Atrial Fibrillation?

    Science.gov (United States)

    ANSWERS by heart Cardiovascular Conditions What Is Atrial Fibrillation? Your heart has a natural pacemaker, called the “sinus node,” that makes electrical signals. These signals cause the heart to contract and pump ...

  1. Atrial therapies reduce atrial arrhythmia burden in defibrillator patients.

    Science.gov (United States)

    Friedman, P A; Dijkman, B; Warman, E N; Xia, H A; Mehra, R; Stanton, M S; Hammill, S C

    2001-08-28

    Approximately 25% of patients who receive an implantable cardioverter-defibrillator (ICD) to treat ventricular tachyarrhythmias have documented atrial tachyarrhythmias before implantation. This study assessed the ability of device-based prevention and termination therapies to reduce the burden of spontaneous atrial tachyarrhythmias. Patients with a standard indication for the implantation of an ICD and 2 episodes of atrial tachyarrhythmias in the preceding year received a dual-chamber ICD (Medtronic 7250 Jewel AF) that uses pacing and shock therapies for prevention and/or termination of atrial tachyarrhythmias. In a multicenter trial, patients were randomized to 3-month periods with atrial therapies "on" or "off" and subsequently crossed over. Analysis was performed on the 52 of 269 patients who had episodes of atrial tachyarrhythmia and had >/=30 days of follow-up with atrial therapies on and off. The atrial therapies resulted in a reduction of atrial tachyarrhythmia burden from a mean of 58.5 to 7.8 h/mo. A paired analysis (Wilcoxon signed-rank test) showed that the median difference in burden (1.1 h/mo) was highly significant (P=0.007). When the subgroup of 41 patients treated only with atrial pacing therapies was analyzed, the reduction in burden persisted (P=0.01). In this study, patients with a standard ICD indication and atrial tachyarrhythmias had a significant reduction in atrial tachyarrhythmia burden with use of atrial pacing and shock therapies.

  2. Changes in left atrial deformation in hypertrophic cardiomyopathy: Evaluation by vector velocity imaging

    Directory of Open Access Journals (Sweden)

    Hala Mahfouz Badran

    2012-12-01

    Full Text Available Objectives: Hypertrophic cardiomyopathy (HCM represents a generalized myopathic process affecting both ventricular and atrial myocardium. We assessed the global and regional left atrial (LA function and its relation to left ventricular (LV mechanics and clinical status in patients with HCM using Vector Velocity Imaging (VVI. Methods: VVI of the LA and LV was acquired from apical four- and two-chamber views of 108 HCM patients (age 40±19years, 56.5% men and 33 healthy subjects, all had normal LV systolic function. The LA subendocardium was traced to obtain atrial volumes, ejection fraction, velocities, and strain (ɛ/strain rate (SR measurements. Results: Left atrial reservoir (ɛsys,SRsys and conduit (early diastolic SRe function were significantly reduced in HCM compared to controls (P-1.8s-1 was 81% sensitive and 30% specific, SRa>-1.5s-1 was 73% sensitive and 40% specific. By multivariate analysis global LVɛsys and LV septal thickness are independent predictors for LAɛsys, while end systolic diameter is the only independent predictor for SRsys, P<.001. Conclusion: Left atrial reservoir and conduit function as measured by VVI were significantly impaired while contractile function was preserved among HCM patients. Left atrial deformation was greatly influenced by LV mechanics and correlated to severity of phenotype.

  3. Changes in left atrial deformation in hypertrophic cardiomyopathy: Evaluation by vector velocity imaging

    Science.gov (United States)

    Badran, Hala Mahfouz; Soltan, Ghada; Hassan, Hesham; Nazmy, Ahmed; Faheem, Naglaa; Saadan, Haythem; Yacoub, Magdi H.

    2012-01-01

    Abstract: Objectives: Hypertrophic cardiomyopathy (HCM) represents a generalized myopathic process affecting both ventricular and atrial myocardium. We assessed the global and regional left atrial (LA) function and its relation to left ventricular (LV) mechanics and clinical status in patients with HCM using Vector Velocity Imaging (VVI). Methods: VVI of the LA and LV was acquired from apical four- and two-chamber views of 108 HCM patients (age 40 ± 19years, 56.5% men) and 33 healthy subjects, all had normal LV systolic function. The LA subendocardium was traced to obtain atrial volumes, ejection fraction, velocities, and strain (ϵ)/strain rate (SR) measurements. Results: Left atrial reservoir (ϵsys,SRsys) and conduit (early diastolic SRe) function were significantly reduced in HCM compared to controls (P  − 1.8s− 1 was 81% sensitive and 30% specific, SRa> − 1.5s− 1 was 73% sensitive and 40% specific. By multivariate analysis global LVϵsys and LV septal thickness are independent predictors for LAϵsys, while end systolic diameter is the only independent predictor for SRsys, P < .001. Conclusion: Left atrial reservoir and conduit function as measured by VVI were significantly impaired while contractile function was preserved among HCM patients. Left atrial deformation was greatly influenced by LV mechanics and correlated to severity of phenotype. PMID:24688992

  4. Spatial Relation Between Left Atrial Anatomical Contact Areas and Circular Activation in Persistent Atrial Fibrillation.

    Science.gov (United States)

    Nakahara, Shiro; Yamaguchi, Takanori; Hori, Yuichi; Anjo, Naofumi; Hayashi, Akiko; Kobayashi, Sayuki; Komatsu, Takaaki; Sakai, Yoshihiko; Fukui, Akira; Tsuchiya, Takeshi; Taguchi, Isao

    2016-05-01

    Atrial low-voltage zones (LVZs) may be related to maintenance of atrial fibrillation (AF). The influence of left atrial (LA) contact areas (CoAs) on reentrant or rotor-like sources maintaining AF has not been investigated. Forty patients with persistent AF (PsAF) were analyzed. Three representative CoA regions in the LA (ascending aorta: anterior wall; descending aorta: left inferior pulmonary vein; and vertebrae: posterior wall) were visualized by enhanced CT. Using circular catheters, the LVZs (80% of the mean AF cycle length. A pivot was defined as the core of the localized circular activation. Anterior (39/40 patients, 98%), left pulmonary vein antrum (27/40, 68%), and posterior (19/40, 48%) CoAs were identified, and 80% (68/85) of those sites were overlapped by or close (<3 mm) to LVZs. Thirty-six (90%) patients demonstrated circular activation (3.1±1.7 sites/patients) along with significantly higher organized dominant frequencies (6.3 ± 0.5 Hz, regularity-index: 0.26 [0.23-0.41]) within the LA, and the average electrogram amplitude of those pivots was 0.30 mV (0.18-0.52). Of those sites, 55% (66/120) were located at or close to CoA regions. Catheter ablation including of LVZs neighboring CoAs terminated AF in 9 (23%) patients. External anatomical structures contacting the LA may be related to unique conduction properties in diseased myocardium necessary for PsAF maintenance. © 2016 Wiley Periodicals, Inc.

  5. Risk Factors for Atrial Fibrillation

    NARCIS (Netherlands)

    B.P. Krijthe (Bouwe)

    2013-01-01

    textabstractAtrial fibrillation is a common cardiac arrhythmia that is characterized by rapid disorganized atrial electrical activity resulting in absence of atrial contractions. It is diagnosed on the basis of typical findings on an electrocardiogram (ECG). The characteristic ECG findings are

  6. 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.

  7. [Morphological and electrophysiological changes of the heart atria in necropsy patients with atrial fibrillation - a pilot study].

    Science.gov (United States)

    Matějková, Adéla; Steiner, Ivo

    2014-01-01

    Atrial fibrillation (AF), the most common supraventricular tachycardia, has a morphological base, so called remodelation of atrial myocardium, with its abnormal conduction pattern as a consequence. The remodelation regards electrical, contractile, and structural properties. In this pilot study we attempted to find relations between the myocardial morphological (scarring, amyloidosis, left atrial enlargement) and electrophysiological (ECG characteristics of the P-wave) changes in patients with AF. We examined 40 hearts of necropsy patients - 20 with a history of AF and 20 with no history of AF. Grossly, the heart weight and the size of the left atrium (LA) were evaluated. Histologically, 7 standard sites from the atria were examined. In each specimen, the degree of myocardial scarring and of deposition of isolated atrial amyloid (IAA) were assessed. We failed to show any significant difference in the P-wave pattern between patients with and without AF. Morphologically, however, there were several differences - the patients with AF had significantly heavier hearts, larger left atria, more severely scarred myocardium of the LA and the atrial septum, and more severe deposition of IAA in both atria in comparison to the control group of patients with sinus rhythm. The left atrial distribution of both fibrosis and amyloidosis was irregular. In patients with AF the former was most pronounced in the LA ceiling while the latter in the LA anterior wall. The entire series showed more marked amyloidosis in the left than in the right atrium. An interesting finding was the universal absence of IAA in the sinoatrial node. The knowledge of distribution of atrial myocardial structural changes could be utilized by pathologists in taking specimens for histology and also by cardiologists in targeting the radiofrequency ablation therapy.

  8. Volume of myocardium perfused by coronary artery branches as estimated from 3D micro-CT images of rat hearts

    Science.gov (United States)

    Lund, Patricia E.; Naessens, Lauren C.; Seaman, Catherine A.; Reyes, Denise A.; Ritman, Erik L.

    2000-04-01

    Average myocardial perfusion is remarkably consistent throughout the heart wall under resting conditions and the velocity of blood flow is fairly reproducible from artery to artery. Based on these observations, and the fact that flow through an artery is the product of arterial cross-sectional area and blood flow velocity, we would expect the volume of myocardium perfused to be proportional to the cross-sectional area of the coronary artery perfusing that volume of myocardium. This relationship has been confirmed by others in pigs, dogs and humans. To test the body size-dependence of this relationship we used the hearts from rats, 3 through 25 weeks of age. The coronary arteries were infused with radiopaque microfil polymer and the hearts scanned in a micro- CT scanner. Using these 3D images we measured the volume of myocardium and the arterial cross-sectional area of the artery that perfused that volume of myocardium. The average constant of proportionality was found to be 0.15 +/- 0.08 cm3/mm2. Our data showed no statistically different estimates of the constant of proportionality in the rat hearts of different ages nor between the left and right coronary arteries. This constant is smaller than that observed in large animals and humans, but this difference is consistent with the body mass-dependence on metabolic rate.

  9. Recurrent atrial myxoma.

    Science.gov (United States)

    Macarie, C; Stoica, E; Chioncel, O; Carp, A; Gherghiceanu, D; Stiru, O; Zarma, L; Herlea, V

    2004-01-01

    We have chosen this case of sporadic atrial myxoma for our presentation because it had a particular evolution, with recurrence at 8 years after surgical excision (echocardiography was performed every year) and a particular diagnostic means - at echocardiographic follow-up, the patient being asymptomatic. This presentation, together with a review of literature included in the article, emphasizes the importance of a careful postoperative follow-up of the patients and the existence of some particular aspects of the evolution and symptomatology of recurrent atrial myxoma.

  10. Thyrotoxic atrial fibrillation.

    Science.gov (United States)

    Parmar, Malvinder S

    2005-01-04

    Atrial fibrillation is the most common cardiac complication of hyperthyroidism and occurs in 15% of patients with hyperthyroidism. It is associated with a higher risk of thromboembolism that often involves the central nervous system. Oral anticoagulation is important in the majority of these patients to prevent thromboembolic complications. These patients require adjustment in the dose of various rate-controlling agents because of increased clearance associated with hyperthyroidism and a decrease in warfarin dosage because of increased clearance of vitamin K-dependent clotting factors. The management of thyrotoxic atrial fibrillation is summarized in this clinical review.

  11. 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

    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

  12. Pharmacological Treatment for Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Kaoru Sugi, MD PhD

    2005-01-01

    Full Text Available Pharmacological treatment for atrial fibrillation has a variety of purposes, such as pharmacological defibrillation, maintenance of sinus rhythm, heart rate control to prevent congestive heart failure and prevention of both cerebral infarction and atrial remodeling. Sodium channel blockers are superior to potassium channel blockers for atrial defibrillation, while both sodium and potassium channel blockers are effective in the maintenance of sinus rhythm. In general, digitalis or Ca antagonists are used to control heart rate during atrial fibrillation to prevent congestive heart failure, while amiodarone or bepridil also reduce heart rates during atrial fibrillation. Anticoagulant therapy with warfarin is recommended to prevent cerebral infarction and angiotensin converting enzyme antagonists or angiotensin II receptor blockers are also used to prevent atrial remodeling. One should select appropriate drugs for treatment of atrial fibrillation according to the patient's condition.

  13. The Pathogenesis of Human Myocardial Infarction

    Science.gov (United States)

    Rona, George

    1966-01-01

    Coronary arteriography, dissection of the coronary arteries and histopathological examination of the heart were carried out in 150 autopsies to study the effect of coronary narrowing and occlusion, of the presence of collaterals, and of coronary artery predominance on the development of myocardial infarction. The thrombosis rate was related to the severity of coronary sclerosis. The development of collaterals was not enhanced by coronary sclerosis and occlusion, and collaterals did not protect the myocardium against reinfarction. Coronary occlusion was regularly demonstrable in recent myocardial infarct cases. The association of atrial and posterior ventricular infarcts was explained by occlusion of their common arterial branch. The interdependence between coronary sclerosis, thrombosis and myocardial infarction in human autopsy material emphasizes the importance of mural coronary artery disease in the genesis of coronary occlusion and myocardial infarction, and it is at variance with statistical data and experimental results. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 6 PMID:5924947

  14. A MicroRNA-Transcription Factor Blueprint for Early Atrial Arrhythmogenic Remodeling

    Directory of Open Access Journals (Sweden)

    Mario Torrado

    2015-01-01

    Full Text Available Spontaneous self-terminating atrial fibrillation (AF is one of the most common heart rhythm disorders, yet the regulatory molecular mechanisms underlying this syndrome are rather unclear. MicroRNA (miRNA transcriptome and expression of candidate transcription factors (TFs with potential roles in arrhythmogenesis, such as Pitx2, Tbx5, and myocardin (Myocd, were analyzed by microarray, qRT-PCR, and Western blotting in left atrial (LA samples from pigs with transitory AF established by right atrial tachypacing. Induced ectopic tachyarrhythmia caused rapid and substantial miRNA remodeling associated with a marked downregulation of Pitx2, Tbx5, and Myocd expression in atrial myocardium. The downregulation of Pitx2, Tbx5, and Myocd was inversely correlated with upregulation of the corresponding targeting miRNAs (miR-21, miR-10a/10b, and miR-1, resp. in the LA of paced animals. Through in vitro transient transfections of HL-1 atrial myocytes, we further showed that upregulation of miR-21 did result in downregulation of Pitx2 in cardiomyocyte background. The results suggest that immediate-early miRNA remodeling coupled with deregulation of TF expression underlies the onset of AF.

  15. A MicroRNA-Transcription Factor Blueprint for Early Atrial Arrhythmogenic Remodeling

    Science.gov (United States)

    Torrado, Mario; Franco, Diego; Lozano-Velasco, Estefanía; Hernández-Torres, Francisco; Calviño, Ramón; Aldama, Guillermo; Centeno, Alberto; Castro-Beiras, Alfonso; Mikhailov, Alexander

    2015-01-01

    Spontaneous self-terminating atrial fibrillation (AF) is one of the most common heart rhythm disorders, yet the regulatory molecular mechanisms underlying this syndrome are rather unclear. MicroRNA (miRNA) transcriptome and expression of candidate transcription factors (TFs) with potential roles in arrhythmogenesis, such as Pitx2, Tbx5, and myocardin (Myocd), were analyzed by microarray, qRT-PCR, and Western blotting in left atrial (LA) samples from pigs with transitory AF established by right atrial tachypacing. Induced ectopic tachyarrhythmia caused rapid and substantial miRNA remodeling associated with a marked downregulation of Pitx2, Tbx5, and Myocd expression in atrial myocardium. The downregulation of Pitx2, Tbx5, and Myocd was inversely correlated with upregulation of the corresponding targeting miRNAs (miR-21, miR-10a/10b, and miR-1, resp.) in the LA of paced animals. Through in vitro transient transfections of HL-1 atrial myocytes, we further showed that upregulation of miR-21 did result in downregulation of Pitx2 in cardiomyocyte background. The results suggest that immediate-early miRNA remodeling coupled with deregulation of TF expression underlies the onset of AF. PMID:26221584

  16. Increased amount of atrial fibrosis in patients with atrial fibrillation secondary to mitral valve disease

    NARCIS (Netherlands)

    Geuzebroek, Guillaume S. C.; van Amersfoorth, Shirley C. M.; Hoogendijk, Mark G.; Kelder, Johannes C.; van Hemel, Norbert M.; de Bakker, Jacques M. T.; Coronel, Ruben

    2012-01-01

    Objective: Atrial fibrosis is related to atrial fibrillation but may differ in patients with mitral valve disease or lone atrial fibrillation. Therefore, we studied atrial fibrosis in patients with atrial fibrillation + mitral valve disease or with lone atrial fibrillation and compared it with

  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

  18. Screening for Atrial Fibrillation

    DEFF Research Database (Denmark)

    Freedman, Ben; Camm, John; Calkins, Hugh

    2017-01-01

    Approximately 10% of ischemic strokes are associated with atrial fibrillation (AF) first diagnosed at the time of stroke. Detecting asymptomatic AF would provide an opportunity to prevent these strokes by instituting appropriate anticoagulation. The AF-SCREEN international collaboration was formed...

  19. Factors of Formation of Various Types of Left Ventricular Diastolic Filling in Adolescents with Myocardium Pathology

    Directory of Open Access Journals (Sweden)

    L.F. Bogmat

    2016-08-01

    Full Text Available Objective: to study the main components of the formation of impaired left ventricular diastolic filling in adolescents with myocardial pathology. Materials and methods. The study involved 110 adolescents with myocardial pathology aged 13–18 years, of which 40 — with heart rhythm disorder, 40 — with dysplastic cardiomyopathy, 30 — with primary hypertension. Morphological and functional parameters of the heart were studied using ultrasound according to standard procedure. Left ventricular diastolic function has been studied in the pulsed wave Doppler mode with transmitral flow mapping from the apical access of four-chambered heart. For an adequate assessment of left ventricular diastolic function and detection of its earliest disorders, adolescents underwent tests with isometric exercise. Based on these results, adolescents were divided in terms of the E/A ratio. In order to identify common latent factors that explain the correlation between indicators, we have used the factor analysis, namely, the principal component analysis. All statistical procedures were performed using application packages Statgraphics Centurion. Results. On the initial stages of formation of diastolic dysfunction of the left ventricular myocardium in adolescents, a significant role is played by a number of factors, which can be conditionally defined as the geometric, functional and neurohumoral factors consistently included in the pathological process. Thus, during the formation of left ventricular diastolic dysfunction type 1, the number one is neurohumoral factor, namely, the activation of the sympathoadrenal system, then peripheral vascular tone is being involved in the pathological process, and, consequently, a geometric factor — changing the sizes of the left atrium. In the formation of left ventricular diastolic dysfunction type 2, the process consistently involves the renin-angiotensin system, namely, renin, a functional factor is presented by the indices

  20. Evaluation of noncoronary sources of left ventricular perfusion to intercoronary collateral-dependent myocardium due to chronic major vessel occlusion: absent contribution of luminal and extracardiac channels

    International Nuclear Information System (INIS)

    Crystal, G.J.; Downey, H.F.; Bashour, F.A.

    1981-01-01

    Liminal contribution to perfusion of collateral-dependent left ventricular (LV) myocardium was evaluated in six dogs. A portion of LV free wall was rendered collateral-dependent by gradual occlusion of left circumflex artery with Ameroid constrictor. Eight to 10 weeks after implantation of constrictor, measurements of LV myocardial flow were made by left atrial injections of 9-10 micro radioactive microspheres. To measure total collateral flow, microspheres were injected under control conditions, and to measure luminal contribution to collateral flow, microspheres were injected after ligation of right coronary artery during extracorporeal perfusion of left common coronary artery (LCCA) with microsphere-free arterial blood, and during stoppage of flow through LCCA. Under control conditions, myocardial blood flow in collateral-dependent region, 1.01 +/- 0.31 ml/min/gm, was not significantly different from that in normal region, 1.06 +/- 0.32 ml/min/gm. Flow from luminal collateral vessels was negligible (less than 0.005 ml/min/gm) in both collateral-dependent and normal myocardium, and was not affected by stoppage of flow through LCCA. These results indicate that luminal collateral vessels, as well as collateral vessels originating from other noncoronary sources, do not contribute significantly to perfusion of normal or collateral-dependent LV myocardium

  1. Pyrophosphate scan of the temporarily ischemized dog myocardium

    Energy Technology Data Exchange (ETDEWEB)

    Duska, F.; Novak, J.; Vizda, J.; Kubicek, J.; Kafka, P.; Veverkova, O.

    1981-12-01

    In 9 dogs a transient myocardial ischemia was provoked using complete occlusion of the ramus interventricularis anterior of the left coronary artery. The occlusion was removed after 5, 10 or 15 min. Four hrs after removal of the occlusion a scan of the myocardium was carried out using sup(99m)Tc-labelled pyrophosphate. In 7 out of 9 dogs under study the scan was markedly positive, in 2 dogs negative. ECG demonstrated ischemic changes practically in all dogs; the changes became normal after removal of the occlusion, namely in 5 to 35 min. The histological examination of the tissue demonstrated in all 9 dogs only a slight impairment of the myocardium.

  2. Absence of rotational activity detected using 2-dimensional phase mapping in the corresponding 3-dimensional phase maps in human persistent atrial fibrillation.

    Science.gov (United States)

    Pathik, Bhupesh; Kalman, Jonathan M; Walters, Tomos; Kuklik, Pawel; Zhao, Jichao; Madry, Andrew; Sanders, Prashanthan; Kistler, Peter M; Lee, Geoffrey

    2018-02-01

    Current phase mapping systems for atrial fibrillation create 2-dimensional (2D) maps. This process may affect the accurate detection of rotors. We developed a 3-dimensional (3D) phase mapping technique that uses the 3D locations of basket electrodes to project phase onto patient-specific left atrial 3D surface anatomy. We sought to determine whether rotors detected in 2D phase maps were present at the corresponding time segments and anatomical locations in 3D phase maps. One-minute left atrial atrial fibrillation recordings were obtained in 14 patients using the basket catheter and analyzed off-line. Using the same phase values, 2D and 3D phase maps were created. Analysis involved determining the dominant propagation patterns in 2D phase maps and evaluating the presence of rotors detected in 2D phase maps in the corresponding 3D phase maps. Using 2D phase mapping, the dominant propagation pattern was single wavefront (36.6%) followed by focal activation (34.0%), disorganized activity (23.7%), rotors (3.3%), and multiple wavefronts (2.4%). Ten transient rotors were observed in 9 of 14 patients (64%). The mean rotor duration was 1.1 ± 0.7 seconds. None of the 10 rotors observed in 2D phase maps were seen at the corresponding time segments and anatomical locations in 3D phase maps; 4 of 10 corresponded with single wavefronts in 3D phase maps, 2 of 10 with 2 simultaneous wavefronts, 1 of 10 with disorganized activity, and in 3 of 10 there was no coverage by the basket catheter at the corresponding 3D anatomical location. Rotors detected in 2D phase maps were not observed in the corresponding 3D phase maps. These findings may have implications for current systems that use 2D phase mapping. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  3. Acute termination of human atrial fibrillation by identification and catheter ablation of localized rotors and sources: first multicenter experience of focal impulse and rotor modulation (FIRM) ablation.

    Science.gov (United States)

    Shivkumar, Kalyanam; Ellenbogen, Kenneth A; Hummel, John D; Miller, John M; Steinberg, Jonathan S

    2012-12-01

    Catheter ablation of atrial fibrillation (AF) currently relies on eliminating triggers, and no reliable method exists to map the arrhythmia itself to identify ablation targets. The aim of this multicenter study was to define the use of Focal Impulse and Rotor Modulation (FIRM) for identifying ablation targets. We prospectively enrolled the first (n = 14, 11 males) consecutive patients undergoing FIRM-guided ablation for persistent (n = 11) and paroxysmal AF at 5 centers. A 64-pole basket catheter was used for panoramic right and left atrial mapping during AF. AF electrograms were analyzed using a novel system to identify sustained rotors (spiral waves), or focal beats (centrifugal activation to surrounding atrium). Ablation was performed first at identified sources. The primary endpoints were acute AF termination or organization (>10% cycle length prolongation). Conventional ablation was performed only after FIRM-guided ablation. Twelve out of 14 cases were mapped. AF sources were demonstrated in all patients (average of 1.9 ± 0.8 per patient). Sources were left atrial in 18 cases, and right atrial in 5 cases, and 21/23 were rotors. FIRM-guided ablation achieved the acute endpoint in all patients, consisting of AF termination in n = 8 (4.9 ± 3.9 minutes at the primary source), and organization in n = 4. Total FIRM time for all patients was 12.3 ± 8.6 minutes. FIRM-guided ablation revealed localized AF rotors/focal sources in patients with paroxysmal, persistent and longstanding persistent AF. Brief targeted FIRM-guided ablation at a priori identified sites terminated or substantially organized AF in all cases prior to any other ablation. © 2012 Wiley Periodicals, Inc.

  4. Genetics Home Reference: familial atrial fibrillation

    Science.gov (United States)

    ... Twitter Home Health Conditions Familial atrial fibrillation Familial atrial fibrillation Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Familial atrial fibrillation is an inherited abnormality of the heart's normal ...

  5. [Echocardiographic diagnosis of atrial thrombosis].

    Science.gov (United States)

    Pinto Tortolero, R; Vargas Barrón, J; Rodas, M A; Díaz de la Vega, V; Horwitz, S

    1982-01-01

    Seventy patients with rheumatic mitral disease were studied by M-Mode and 2D echocardiography in order to detect left atrial thrombosis before surgery. Thrombosis were suspected by the observation of abnormal echoes in the left atrium. During surgery 17 (24%) patients had atrial thrombosis. It had been suspected by echocardiography in 12 (sensitivity 70%). In 53 patients thrombosis were not found during surgery; in 46 the echo had been also negative (specificity 86%). There was a false positive detection of thrombosis by echo in 7 patients (14%) and false negativity in 5 (30%). Patients with atrial thrombosis had atrial fibrilation in 91% of cases; and the most frequent valvular disease was mitral stenosis. There was not a direct relationship among existence of left atrial thrombosis and the anteroposterior diameter of the left atrium as measured by echo. We conclude that echocardiography has good specificity to rule out atrial thrombosis and moderate sensitivity to detect it in rheumatic mitral disease.

  6. EXAMINATION OF ELECTROPHYSIOLOGICAL PARAMETERS OF THE ATRIUMS IN PATIENTS WITH LONG-TERM PERSISTENT FORM OF ATRIAL FIBRILLATION AND VALVULAR HEART DISEASE

    Directory of Open Access Journals (Sweden)

    A. A. Kulikov

    2017-01-01

    Full Text Available The study objective is to examine electrophysiological parameters of atrial myocardium, characteristics of atrioventricular conduction, and potential factors affecting recurrent atrial fibrillation (AF in patients with persistent and long-term persistent forms of AF prior to the Labirynth IIIB surgery with single-step correction of valvular heart disease.Materials and methods. The study included 100 adults (48 men, 52 women with persistent and long-term persistent forms of AF and different valvular heart diseases. Mean patient age was 59 years. Mean AF duration was 4 years. All patients were prescribed antiarrhythmic therapy but it proved ineffective. In 15 % of patients, restoration of the sinus rhythm was attempted through electrical cardioversion but long-term control of the sinus rhythm wasn’t achieved. All patients were diagnosed with organic pathology of the mitral valve. Also, in 80 % of patients, relative insufficiency of the tricuspid valve was detected. Chronic heart failure functional class per NYHA was III. Size of the left atrium was 5 cm, mean left ventricular ejection fraction was 61 %. All patients underwent electrical cardioversion. After successful restoration of the sinus rhythm, endocardial electrophysiology study (EES of the heart was performed. Then, correction of valvular pathologies and the Labyrinth IIIB surgery were performed. Results. Examination of refractoriness of different parts of the atriums has shown that effective refractory period (ERP of the atrioventricular node was minimal compared to other parts of the atriums. Maximal ERP duration was observed in the upper part of the right atrium. Therefore, in patients with long history of AF, heterogeneity of atrial myocardium ERP duration is observed. In 17 % of patients, atrial vulnerability was detected. The area of atrial vulnerability was always associated with ERP. Its duration in patients with atrial vulnerability was significantly higher.Conclusion. Long

  7. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. ANP (Atrial Natriuretic Peptide presence in the heart of a tunicate, Ciona intestinalis.

    Directory of Open Access Journals (Sweden)

    Aldo Gerbino

    2010-06-01

    Full Text Available Atrial natriuretic peptide was found in the heart of vertebrates, we studied the ANP presence in the heart of Ciona intestinalis. This is animal is very important because of the its evolutionary position between invertebrates and vertebrates. ANP presence was only revealed in myoepithelial cells of the myocardium. Results suggest the hypothesis that ANP is present not only in the vertebrates but also in the invertebrates and in Ciona heart ANP might play a similar role like in the heart of vertebrates.

  9. Arachidonic acid metabolism in fibroblasts derived from canine myocardium

    International Nuclear Information System (INIS)

    Weber, D.R.; Prescott, S.M.

    1986-01-01

    Canine fibroblasts from normal or healing infarcted myocardium were grown in culture. The cells were morphologically indistinguishable, but the doubling time of cells from healing myocardium was 39.6 +/- 3.5 hr whereas that of normals was 24 +/- 3.7 (n=5, p 3 H]arachidonate (AA) into phospholipids. Calcium ionophore A23187 (10 μM) caused release and metabolism of [ 3 H] AA. A23187 or AA (10μM) induced production of 6-keto PGF1α, PGE2, and a hydroxy metabolite of AA. RIA of 6-keto PGF1α showed that subconfluent cells from healing myocardium produced 1202 +/- 354 pg/mg protein whereas that of normals was 551 +/- 222 (n=7, p 3 H]AA released but did not metabolize [ 3 H]AA. In coincubations, fibroblasts incorporated myocyte-derived AA. Subsequent stimulation of the fibroblasts with A23187 induced the synthesis of 6-keto PGF1α, PGE2 and a hydroxy metabolite. The fibroblast content of healing myocardium was 35-1000 times that of normal tissue (n=7). Thus even a moderate change in AA metabolism, amplified by the AA released from deteriorating myocytes, may be a significant physiologic or pathologic event

  10. Multimodality imaging demonstrates trafficking of liposomes preferentially to ischemic myocardium

    International Nuclear Information System (INIS)

    Lipinski, Michael J.; Albelda, M. Teresa; Frias, Juan C.; Anderson, Stasia A.; Luger, Dror; Westman, Peter C.; Escarcega, Ricardo O.; Hellinga, David G.; Waksman, Ron; Arai, Andrew E.; Epstein, Stephen E.

    2016-01-01

    Introduction: Nanoparticles may serve as a promising means to deliver novel therapeutics to the myocardium following myocardial infarction. We sought to determine whether lipid-based liposomal nanoparticles can be shown through different imaging modalities to specifically target injured myocardium following intravenous injection in an ischemia–reperfusion murine myocardial infarction model. Methods: Mice underwent ischemia–reperfusion surgery and then either received tail-vein injection with gadolinium- and fluorescent-labeled liposomes or no injection (control). The hearts were harvested 24 h later and underwent T1 and T2-weighted ex vivo imaging using a 7 Tesla Bruker magnet. The hearts were then sectioned for immunohistochemistry and optical fluorescent imaging. Results: The mean size of the liposomes was 100 nm. T1-weighted signal intensity was significantly increased in the ischemic vs. the non-ischemic myocardium for mice that received liposomes compared with control. Optical imaging demonstrated significant fluorescence within the infarct area for the liposome group compared with control (163 ± 31% vs. 13 ± 14%, p = 0.001) and fluorescent microscopy confirmed the presence of liposomes within the ischemic myocardium. Conclusions: Liposomes traffic to the heart and preferentially home to regions of myocardial injury, enabling improved diagnosis of myocardial injury and could serve as a vehicle for drug delivery.

  11. Multimodality imaging demonstrates trafficking of liposomes preferentially to ischemic myocardium

    Energy Technology Data Exchange (ETDEWEB)

    Lipinski, Michael J., E-mail: mjlipinski12@gmail.com [MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC (United States); Albelda, M. Teresa [GIBI2" 3" 0, Grupo de Investigación Biomédica en Imagen, IIS La Fe, Valencia (Spain); Frias, Juan C. [Departamento de Ciencias Biomédicas, Universidad CEU Cardenal Herrera, Valencia (Spain); Anderson, Stasia A. [Advanced Cardiovascular Imaging Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (United States); Luger, Dror; Westman, Peter C.; Escarcega, Ricardo O.; Hellinga, David G.; Waksman, Ron [MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC (United States); Arai, Andrew E. [Advanced Cardiovascular Imaging Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (United States); Epstein, Stephen E. [MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC (United States)

    2016-03-15

    Introduction: Nanoparticles may serve as a promising means to deliver novel therapeutics to the myocardium following myocardial infarction. We sought to determine whether lipid-based liposomal nanoparticles can be shown through different imaging modalities to specifically target injured myocardium following intravenous injection in an ischemia–reperfusion murine myocardial infarction model. Methods: Mice underwent ischemia–reperfusion surgery and then either received tail-vein injection with gadolinium- and fluorescent-labeled liposomes or no injection (control). The hearts were harvested 24 h later and underwent T1 and T2-weighted ex vivo imaging using a 7 Tesla Bruker magnet. The hearts were then sectioned for immunohistochemistry and optical fluorescent imaging. Results: The mean size of the liposomes was 100 nm. T1-weighted signal intensity was significantly increased in the ischemic vs. the non-ischemic myocardium for mice that received liposomes compared with control. Optical imaging demonstrated significant fluorescence within the infarct area for the liposome group compared with control (163 ± 31% vs. 13 ± 14%, p = 0.001) and fluorescent microscopy confirmed the presence of liposomes within the ischemic myocardium. Conclusions: Liposomes traffic to the heart and preferentially home to regions of myocardial injury, enabling improved diagnosis of myocardial injury and could serve as a vehicle for drug delivery.

  12. Atrial fibrillation in the elderly

    Science.gov (United States)

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

    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. PMID:22916053

  13. The effect of activation rate on left atrial bipolar voltage in patients with paroxysmal atrial fibrillation.

    Science.gov (United States)

    Williams, Steven E; Linton, Nick; O'Neill, Louisa; Harrison, James; Whitaker, John; Mukherjee, Rahul; Rinaldi, Christopher A; Gill, Jaswinder; Niederer, Steven; Wright, Matthew; O'Neill, Mark

    2017-09-01

    Bipolar voltage is used during electroanatomic mapping to define abnormal myocardium, but the effect of activation rate on bipolar voltage is not known. We hypothesized that bipolar voltage may change in response to activation rate. By examining corresponding unipolar signals we sought to determine the mechanisms of such changes. LA extrastimulus mapping was performed during CS pacing in 10 patients undergoing first time paroxysmal atrial fibrillation ablation. Bipolar and unipolar electrograms were recorded using a PentaRay catheter (4-4-4 spacing) and indifferent IVC electrode, respectively. An S1S2 pacing protocol was delivered with extrastimulus coupling interval reducing from 350 to 200 milliseconds. At each recording site (119 ± 37 per LA), bipolar peak-to-peak voltage, unipolar peak to peak voltage and activation delay between unipole pairs was measured. Four patterns of bipolar voltage/extrastimulus coupling interval curves were seen: voltage attenuation with plateau voltage >1 mV (48 ± 15%) or voltage unaffected by coupling interval with plateau voltage >1 mV (17 ± 10%) or voltage attenuation were associated with significantly greater unipolar voltage attenuation at low (25 ± 28 mV/s vs. 9 ± 11 mV/s) and high (23 ± 29 mV/s vs. 6 ± 12 mV/s) plateau voltage sites (P voltage attenuation (P = 0.026). Bipolar electrogram voltage is dependent on activation rate at a significant proportion of sites. Changes in unipolar voltage and timing underlie these effects. These observations have important implications for use of voltage mapping to delineate abnormal atrial substrate. © 2017 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals, Inc.

  14. Right atrial lipoma

    Directory of Open Access Journals (Sweden)

    Pêgo-Fernandes Paulo M.

    2003-01-01

    Full Text Available Benign cardiac tumors are rare, and lipomas are among those less frequently found. We report the case of a 48-year-old male complaining of high blood pressure and epistaxis in the last 2 months, with a diagnosis of right atrial lipoma established on echocardiography, magnetic resonance imaging, and anatomicopathological examination. The tumor was successfully removed, and up to 42 months after surgical excision, no evidence of tumor relapse was observed.

  15. 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.

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    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 hearts....

  17. Effects of acute and chronic uremia on active cation transport in rat myocardium

    Energy Technology Data Exchange (ETDEWEB)

    Druml, W.; Kelly, R.A.; England, B.K.; O' Hara, D.S.; Mitch, W.E. (Brigham and Women' s Hospital, Boston, MA (USA))

    1990-12-01

    As abnormalities of active cation transport could contribute to the genesis of uremic cardiomyopathy, we investigated myocardial sodium pump function in rats with acute renal failure (ARF) and with a model of experimental chronic renal failure (CRF) that has metabolic similarities to advanced chronic uremia in humans. CRF rats were hypertensive and had left ventricular hypertrophy (33% higher heart:body weight ratio; P less than 0.01) at four weeks compared to pair-fed sham-operated rats. Importantly, both ouabain- and furosemide-sensitive 86Rb uptake rates were unchanged in left ventricular myocardial slices from CRF, and the intracellular sodium concentration was not different from that of control rats even though skeletal muscle sodium was increased, as we found previously. Insulin-stimulated, ouabain-sensitive 86Rb influx was also preserved. There also were no abnormalities in myocardium cation transport in rats with ARF. However, (3H)ouabain binding was decreased 45% in CRF rats (P less than 0.01); it was unchanged in acute uremia. Decreased ouabain binding in chronic uremia was due entirely to fewer low affinity (3H)ouabain binding sites (the binding affinity for ouabain was unaffected). We conclude that in chronic, (but not acute) renal failure, sodium pump number is reduced in myocardium but intracellular sodium is unchanged and active cation flux rates are maintained. These results emphasize that in rats with chronic uremia, intracellular sodium homeostasis is preserved in myocardium, despite the presence of marked abnormalities of active cation transport in skeletal muscle that are characteristic of chronic uremia.

  18. Pharmacologic Therapy in the Elderly with Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Shih-Huang Lee

    2008-03-01

    Full Text Available Atrial fibrillation (AF is the most common sustained arrhythmia, and its prevalence significantly increases with age. Morphologic changes in the atrial myocardium associated with AF may result from underlying cardiovascular disease and/or physiologic aging processes. Congestive heart failure, tachycardia-induced cardiomyopathy and thromboembolic events resulting from AF are more common in elderly patients. It is important to assess any comorbidity and potential triggers of AF before considering pharmacologic therapy for AF. Proper rate control should include control in response to exercise, together with an avoidance of bradycardias and symptomatic pauses in patients with AF. Digoxin, β-blockers and calcium channel blockers can all be effective in controlling ventricular rate in elderly patients with AF. In the elderly, amiodarone is probably the safest drug for short-term administration to exert chemical cardioversion, facilitate electrical cardioversion, and prevent recurrence of AF. Warfarin has been shown to be highly effective in preventing stroke in the elderly with AF; however, many studies also have documented underuse of warfarin, may be because of the increased risk of warfarin-induced hemorrhage in such patients. These findings have raised concerns regarding quality of care, physician adherence to guidelines, and translation of clinical trial results into real-world practice in anticoagulation therapy in the elderly with AF. [International Journal of Gerontology 2008; 2(1: 1–6

  19. New technologies in treatment of atrial fibrillation in cardiosurgical patients

    Science.gov (United States)

    Evtushenko, A. V.; Evtushenko, V. V.; Bykov, A. N.; Sergeev, V. S.; Syryamkin, V. I.; Kistenev, Yu. V.; Anfinogenova, Ya. D.; Smyshlyaev, K. A.; Kurlov, I. O.

    2015-11-01

    The article is devoted to the evaluation of the results of clinical application of penetrating radiofrequency ablation techniques on atrial myocardium. Total operated on 241 patients with valvular heart disease and coronary heart disease complicated with atrial fibrillation. All operations were performed under cardiopulmonary bypass and cardioplegia. The main group consists of 141 patients which were operated using penetrating technique radiofrequency exposure. The control group consisted of 100 patients who underwent surgery with the use of "classical" monopolar RF-ablation technique. Both groups were not significantly different on all counts before surgery. Patients with previous heart surgery were excluded during the selection of candidates for the procedure, due to the presence of adhesions in the pericardium, that do not allow good visualization of left atrium, sufficient to perform this procedure. Penetrating technique has significantly higher efficiency compared to the "classic" technique in the early and long-term postoperative periods. In the early postoperative period, its efficiency is 93%, and in the long term is 88%. The efficacy of "classical" monopolar procedure is below: 86% and 68% respectively.

  20. Novel Percutaneous Epicardial Autonomic Modulation in the Canine for Atrial Fibrillation: Results of an Efficacy and Safety Study

    Science.gov (United States)

    Madhavan, Malini; Venkatachalam, K. L.; Swale, Matthew J.; DeSimone, Christopher V.; Gard, Joseph J.; Johnson, Susan B.; Suddendorf, Scott H.; Mikell, Susan B.; Ladewig, Dorothy J.; Nosbush, Toni Grabinger; Danielsen, Andrew J.; Knudson, Mark; Asirvatham, Samuel J.

    2016-01-01

    Background Endocardial ablation of atrial ganglionated plexi (GP) has been described for treatment of atrial fibrillation (AF). Our objective in this study was to develop percutaneous epicardial GP ablation in a canine model using novel energy sources and catheters. Methods Phase 1: The efficacy of several modalities to ablate the GP was tested in an open chest canine model (n=10). Phase 2: Percutaneous epicardial ablation of GP was done in 6 dogs using the most efficacious modality identified in phase 1 using 2 novel catheters. Results Phase 1: DC in varying doses [blocking (7 -12μA), electroporation (300-500μA), ablation (3000- 7500μA)], radiofrequency ablation (25–50 W), ultrasound (1.5MHz), and alcohol (2-5ml) injection were successful at 0/8, 4/12, 5/7, 3/8, 1/5 and 5/7 GP sites. DC (500–5000μA) along with alcohol irrigation was tested in phase 2. Phase 2: Percutaneous epicardial ablation of the right atrium, oblique sinus, vein of Marshall, and transverse sinus GP was successful in 5/6 dogs. One dog died of ventricular fibrillation (VF) during DC ablation at 5000 μA. Programmed stimulation induced AF in 6 dogs pre-ablation and no atrial arrhythmia in 3, flutter in 1 and AF in 1 post-ablation. Heart rate, blood pressure, effective atrial refractory period and local atrial electrogram amplitude did not change significantly post-ablation. Microscopic examination showed elimination of GP, and minimal injury to atrial myocardium. Conclusion Percutaneous epicardial ablation of GP using direct current and novel catheters is safe and feasible and may be used as an adjunct to pulmonary vein isolation in the treatment of atrial fibrillation in order to minimize additional atrial myocardial ablation. PMID:26854009

  1. Effects of Prolonged Spaceflight on Atrial Size, Atrial Electrophysiology, and Risk of Atrial Fibrillation.

    Science.gov (United States)

    Khine, Htet W; Steding-Ehrenborg, Katarina; Hastings, Jeffrey L; Kowal, Jamie; Daniels, James D; Page, Richard L; Goldberger, Jeffery J; Ng, Jason; Adams-Huet, Beverley; Bungo, Michael W; Levine, Benjamin D

    2018-05-01

    The prevalence of atrial fibrillation (AF) in active astronauts is ≈5%, similar to the general population but at a younger age. Risk factors for AF include left atrial enlargement, increased number of premature atrial complexes, and certain parameters on signal-averaged electrocardiography, such as P-wave duration, root mean square voltage for the terminal 20 ms of the signal-averaged P wave, and P-wave amplitude. We aimed to evaluate changes in atrial structure, supraventricular beats, and atrial electrophysiology to determine whether spaceflight could increase the risk of AF. Thirteen astronauts underwent cardiac magnetic resonance imaging to assess atrial structure and function before and after 6 months in space and high-resolution Holter monitoring for multiple 48-hour time periods before flight, during flight, and on landing day. Left atrial volume transiently increased after 6 months in space (12±18 mL; P =0.03) without changing atrial function. Right atrial size remained unchanged. No changes in supraventricular beats were noted. One astronaut had a large increase in supraventricular ectopic beats but none developed AF. Filtered P-wave duration did not change over time, but root mean square voltage for the terminal 20 ms decreased on all fight days except landing day. No changes in P-wave amplitude were seen in leads II or V 1 except landing day for lead V 1 . Six months of spaceflight may be sufficient to cause transient changes in left atrial structure and atrial electrophysiology that increase the risk of AF. However, there was no definite evidence of increased supraventricular arrhythmias and no identified episodes of AF. © 2018 American Heart Association, Inc.

  2. Incidence of stunned, hibernating and scarred myocardium in ischaemic cardiomyopathy

    International Nuclear Information System (INIS)

    Hernandez-Pampaloni, Miguel; Morita, Koichi; Dutka, David P.; Camici, Paolo G.; Bax, Jeroen J.

    2005-01-01

    Different criteria to identify residual viability in chronically dysfunctioning myocardium in patients with coronary artery disease (CAD) can be derived by the combined assessment of myocardial blood flow (MBF) and glucose utilisation (MRG) using positron emission tomography (PET). The aim of this study was to evaluate, in a large number of patients, the prevalence of these different patterns by purely quantitative means. One hundred and sixteen consecutive patients with ischaemic cardiomyopathy (LVEF ≤40%) underwent resting 2D echocardiography to assess regional contractile function (16-segment model). PET with 15 O-labelled water (H 2 15 O) and 18 F-fluorodeoxyglucose (FDG) was used to quantify MBF and MRG during hyperinsulinaemic euglycaemic clamp. Dysfunctional segments with normal MBF (≥0.6 ml min -1 g -1 ) were classified as stunned, and segments with reduced MBF ( -1 g -1 ) as hibernating if MRG was ≥0.25 μmol min -1 g -1 . Segments with reduced MBF and MRG -1 g -1 were classified as transmural scars and segments with reduced MBF and MRG between 0.20 and 0.25 μmol min -1 g -1 as non-transmural scars. Eight hundred and thirty-four (46%) segments were dysfunctional. Of these, 601 (72%) were chronically stunned, with 368 (61%) having normal MRG (0.47±0.20 μmol min -1 g -1 ) and 233 (39%) reduced MRG (0.16±0.05 μmol min -1 g -1 ). Seventy-four (9%) segments with reduced MBF had preserved MRG (0.40±0.18 μmol min -1 g -1 ) and were classified as hibernating myocardium. In addition, 15% of segments were classified as transmural and 4% as non-transmural scar. The mean MBF was highest in stunned myocardium (0.95±0.32 ml min -1 g -1 ), intermediate in hibernating myocardium and non-transmural scars (0.47±0.09 ml min -1 g -1 and 0.48±0.08 ml min -1 g -1 , respectively), and lowest in transmural scars (0.40±0.14 ml min -1 g -1 , P -1 g -1 vs 0.46±0.20 μmol min -1 g -1 , NS), and lowest in stunned myocardium with reduced MRG and transmural scars

  3. Dynamic MRI of ferumoxide-labeled bone mesenchmal stem cells after transplantation in infarcted myocardium

    International Nuclear Information System (INIS)

    Liu Qiong; Zhao Shihua; Lu Minjie; Jiang Shiliang; Yan Chaowu; Zhang Yan; Meng Liang; Tang Yue; Meng Xianmin; Wei Yingjie; Wang Qingzhi

    2009-01-01

    Objective: To investigate the ability of magnetic resonance imaging (MRI) in tracking magnetically labeled mesenchymal stem cells (MR-MSCs) in a swine myocardial infarction (MI) model. Methods: Adult Chinese mini-pigs (n=6) were subjected to open-chest experimental MI operation. Their autogeneic bone marrow-derived mesenchymal stem cells (MSCs) was cultured and doubly labeled with ferumoxides and DAPI. On the 14 th day after MSCs transplantation, the size and location of the myocardial infarction were assessed by using delayed-enhancement MRI (DE-MRI). Then the labeled MSCs were injected intramyocardially into peri-infarct zone and normal myocardium. At 24 hrs and 3 weeks after injection, the contrast and the volume of the MR-MSCs hypointense lesion from the MR images were acquired, and the contrast was determined using the difference in signal intensity between the hypointense and normal myocardium divided by signal intensity of the normal region. After humane euthanasia, the heart was excised and histology corresponding to MRI slices that demonstrated MR-MSCs lesions was performed. Repeated-measures ANOVA and a paired t test were used for comparison of the contrast and the volume of the MR-MSCs hypointense lesion at different time points. Comparisons between independent groups were performed with the standard Student t test. Results: The labeling efficiency of ferumoxides and DAPI was 100%. On the 14 th day after the MI operation, the average percentage of infracted myocardial area was (33.6±8.9)%. Twenty- four hours after MSCs transplantation, MSCs injection sites appeared as ovoid hypointensive lesions with sharp border on T 2 * images. At 24 h after injection, the signal contrast [(67.00±5.48)% vs (61.92±7.76)%,t=1.65, P=0.1158] and the size [(0.56±0.24) cm 2 vs (0.52±0.25) cm 2 , t=0.39, P=0.7044] of the lesions showed no statistical difference between the peri-infarct zone and the normal myocardium. At 3 weeks after injection, the signal contrast

  4. Atrial fibrillation: Therapeutic potential of atrial K+ channel blockers.

    Science.gov (United States)

    Ravens, Ursula; Odening, Katja E

    2017-08-01

    Despite the epidemiological scale of atrial fibrillation, current treatment strategies are of limited efficacy and safety. Ideally, novel drugs should specifically correct the pathophysiological mechanisms responsible for atrial fibrillation with no other cardiac or extracardiac actions. Atrial-selective drugs are directed toward cellular targets with sufficiently different characteristics in atria and ventricles to modify only atrial function. Several potassium (K + ) channels with either predominant expression in atria or distinct electrophysiological properties in atria and ventricles can serve as atrial-selective drug targets. These channels include the ultra-rapidly activating, delayed outward-rectifying Kv1.5 channel conducting I Kur , the acetylcholine-activated inward-rectifying Kir3.1/Kir3.4 channel conducting I K,ACh , the Ca 2+ -activated K + channels of small conductance (SK) conducting I SK , and the two pore domain K + (K2P) channels TWIK-1, TASK-1 and TASK-3 that are responsible for voltage-independent background currents I TWIK-1 , I TASK-1 , and I TASK-3 . Here, we briefly review the characteristics of these K + channels and their roles in atrial fibrillation. The antiarrhythmic potential of drugs targeting the described channels is discussed as well as their putative value in treatment of atrial fibrillation. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. [Atrial fibrillation in elderly].

    Science.gov (United States)

    Arquizan, Caroline

    2012-11-01

    Atrial fibrilation (AF) is frequent and a strong risk factor for ischemic stroke in elderly. Ischemic stroke in patients with AF are more severe. Vitamine K antagonist therapy is highly effective for stroke prevention but is associated with hemorrhagic risk. The new oral anticoagulants (direct thrombin inhibitor [dabigatran], and direct factor Xa inhibitors [rivaroxaban and apixaban]) have all shown non inferiority or superiority, with better safety, considering the risk of intracranial haemorrhage. On this basis, it is justified to give them in priority in the vast majority of patients with AF, the choice of the drug and the dose is individual.

  6. 99m Technetium pyrophosphate myocardium scintigraphy. First results

    International Nuclear Information System (INIS)

    Toussaint, Paul.

    1976-01-01

    99m technetium pyrophosphate myocardium scintigraphy is a very recent examination technique. This work gives the results obtained on 61 patients. As a vector of the isotope, pyrophosphate has the advantage over polyphosphate of a fast bone uptake there it should be stressed that a 90 minute pause is necessary between the intraveinous injection of the isotope and the photographic recording so that the reading is not troubled by the labelled intracardiac blood pool image, an image quality criterion being the estimation of a good costal fixation which in fact appears sooner or later according to the subject. The role of pyrophosphate, chelator of calcium in fixation of the isotope on the myocardium, could be explained by the fast appearance of 'dense bodies', made up of calcium hydroxyapathice crystals, in the mitochondria of myocardium cells having undergone an irreversible necrotic process. The choice of 99 m technetium is based on its ease of use: 6 hour half-life, high-energy pure gamma emission at 140 keV. The fixed image studied under two incidences, front and left anterior oblique, is obtained from mobile images given by the scintillation camera used in connection with a data processing system. Several facts are underlined, explaining the disadvantages, advantages and indications of the method [fr

  7. Study of shape memory alloy fibers for the development of artificial myocardium.

    Science.gov (United States)

    Hassoulas, Ioannis A; Ladopoulos, Vlassios S; Kalogerakos, Paris-Dimitrios K

    2010-01-01

    Circulatory support devices are employed to treat heart failure. Such a device could be made from shape memory alloy (SMA) fibers. These Ni-Ti fibers contract when electric current flows through them, thus resembling artificial muscles. An artificial myocardium device made from SMA fibers can directly compress the epicardial surface of a failing heart, thus contributing to the pumping action. Unlike modern mechanical circulatory support devices, there is no blood-contacting surface to provoke thromboembolism, hemorrhage, inflammatory response or hemolysis. The experimental setup permitted a detailed study of a sample SMA fiber with great accuracy while the ambient temperature was controlled to resemble that of the human body. The current profile through the fiber was controlled (current shaping, CS) by a microcontroller and a portable computer. Parameters such as strain, contraction and relaxation velocities and the effect of ambient temperature were measured. The contraction and relaxation velocities were measured after applying various effective currents. It was found that the contraction velocity could be manipulated to reach that of the healthy myocardium through CS. On the other hand, the relaxation velocity was independent of the contraction velocity. A cardiac assist device can be made from SMA fibers. More studies need to be conducted in this direction.

  8. 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......, and hospitalizations. During the fourth Atrial Fibrillation competence NETwork/European Heart Rhythm Association (AFNET/EHRA) consensus conference, we identified the following opportunities to personalize management of AF in a better manner with a view to improve outcomes by integrating atrial morphology and damage...

  9. Atrial and ventricular function after cardioversion of atrial fibrillation.

    Science.gov (United States)

    Xiong, C.; Sonnhag, C.; Nylander, E.; Wranne, B.

    1995-01-01

    OBJECTIVE--Previous studies on atrial recovery after cardioversion of atrial fibrillation have not taken into account new knowledge about the pathophysiology of transmitral and transtricuspid flow velocity patterns. It is possible to shed further light on this problem if atrioventricular inflow velocity, venous filling pattern, and atrioventricular annulus motion are recorded and interpreted together. DESIGN--Prospective examinations of mitral and tricuspid transvalvar flow velocities, superior caval and pulmonary venous filling, and mitral and tricuspid annulus motion were recorded using Doppler echocardiography. Examinations were performed before and 24 hours, 1 month, and 20 months after cardioversion. SETTING--Tertiary referral centre for cardiac disease with facilities for invasive and non-invasive investigation. PATIENTS--16 patients undergoing cardioversion of atrial fibrillation in whom sinus rhythm had persisted for 24 hours or more. RESULTS--Before conversion there was no identifiable A wave in transvalvar flow recordings. The total motion of the tricuspid and mitral annulus was subnormal and there was no identifiable atrial component. Venous flow patterns in general showed a low systolic velocity. After conversion, A waves and atrial components were seen in all patients and increased significantly (P atrial components, an increased systolic component of venous inflow, an increased A wave velocity, and a decreased E/A ratio of the transvalvar velocity curves. The ventricular component of annulus motion was unchanged. Changes in general occurred earlier on the right side than the left. CONCLUSIONS--This study indicates that, in addition to the previously known electromechanical dissociation of atrial recovery that exists after cardioversion of atrial fibrillation, there may also be a transient deterioration of ventricular function modulating the transvalvar inflow velocity recordings. Function on the right side generally becomes normal earlier than on the

  10. Atrial fibrillation and hyperthyroidism: A literature review.

    Science.gov (United States)

    Reddy, Vivek; Taha, Wael; Kundumadam, Shanker; Khan, Mazhar

    Atrial fibrillation is the most common arrhythmia worldwide with increasing frequency noted with age. Hyperthyroidism is a well-known cause of atrial fibrillation with a 16%-60% prevalence of atrial fibrillation in patients with known hyperthyroidism Ross et al. (2016). While hyperthyroidism as a causative factor of atrial fibrillation is well established, this literature review aims to answer several questions on this topic including: 1. The relationship of atrial fibrillation to hyperthyroidism 2. Atrial fibrillation as a predictor of hyperthyroidism 3. The pathophysiology of thyrotoxic atrial fibrillation 4. Subclinical hyperthyroidism and the relationship with atrial fibrillation 5. Cardioversion and Catheter ablation of hyperthyroid patients with atrial fibrillation 6. Thrombotic risk of hyperthyroid patients with atrial fibrillation 7. Management of Thyrotoxic Atrial fibrillation 8. Pharmacological rhythm control in patients with hyperthyroidism and atrial fibrillation 9. Treatment of Hyperthyroidism to prevent atrial fibrillation 10. Clinical Implications of Hyperthyroidism and Atrial Fibrillation. Copyright © 2017 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

  11. Evalutating Inward Rectifier Current Inhibiton for Treatment of Atrial Fibrillation

    NARCIS (Netherlands)

    Ji, Yuan

    2017-01-01

    Atrial Fibrillation (AF) is one of the most common forms of cardiac arrhythmia and affects a large percentage of the human population, especially in the elderly. Currently, more than 6 million Europeans suffer from AF, and due to ageing this number will at least double in the next 50 years.

  12. 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

  13. Role of the Atrioventricular Node in Atrial Fibrillation

    NARCIS (Netherlands)

    Meijler, F.L.; Wittkampf, F.H.M.

    1997-01-01

    Atrial fibrillation (AF) is probably the most cornmon cardiac arrhythmia in humans, particularly in the elderly (1-3). The irregularity and inequality of the he art beat first described by Hering in 1903 were, and continue to be, the landmark of the clinical diagnosis of AF (4,5). Sir Thomas

  14. The possibilities of using scale-selective polarization cartography in diagnostics of myocardium pathologies

    Science.gov (United States)

    Ushenko, Yu. A.; Wanchuliak, O. Y.

    2013-06-01

    The optical model of polycrystalline networks of myocardium protein fibrils is presented. The technique of determining the coordinate distribution of polarization azimuth of the points of laser images of myocardium histological sections is suggested. The results of investigating the interrelation between the values of statistical (statistical moments of the 1st-4th order) parameters are presented which characterize distributions of wavelet-coefficients polarization maps of myocardium layers and death reasons.

  15. Mismatched regional myocardial uptake between [sup 123]I-BMIPP and [sup 201]Tl SPECT; Comparison between hypertrophic myocardium and dilated myocardium

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Makoto; Ichiya, Yuichi; Kuwabara, Yasuo; Sasaki, Masayuki; Fukumura, Toshimitsu; Masuda, Kouji; Ejima, Junichi; Tsuda, Yasuo (Kyushu Univ., Fukuoka (Japan). Faculty of Medicine)

    1992-07-01

    The distribution of a new myocardial fatty acid metabolic agent [sup 123]I-BMIPP was compared in 6 each patients with hypertrophic myocardium (4 cases of hypertensive heart disease and 2 of hypertrophic cardiomyopathy) and dilated myocardium (4 of dilated type of valvular heart disease and 2 of dilated cardiomyopathy) with that of [sup 201]Tl. Mismatched regional myocardial uptake between [sup 123]I-BMIPP and [sup 201]Tl SPECT was observed in all of the hypertrophic myocardium, however no but one in the dilated myocardium. Relative increase or decrease in regional BMIPP from the images of 20 min and to those of 4 h was observed in 3 cases of the hypertrophic myocardium. FDG-PET was performed in 2 cases of the hypertrophic myocardium. The distribution of FDG was different from neither those of BMIPP nor Tl in a hypertrophic cardiomyopathy case with the reserved distribution of BMIPP and Tl. Although more investigations are necessary, we concluded that [sup 123]I-BMIPP is a promising radiopharmaceutical for evaluating myocardial fatty acid metabolism in hypertrophic myocardium. (author).

  16. The comparison of nitroglycerin interventional dual-isotope myocardium perfusion imaging and 201Tl re-injection imaging to detect viable myocardium

    International Nuclear Information System (INIS)

    Gao Zhou; Shi yu; Chen Hongyan; Jia Shaowei

    2002-01-01

    Objective: Employing the differences in physical properties of 99m Tc-MIBI and 201 Tl, the authors discuss the contrast result of nitroglycerin interventional dual-isotope myocardium perfusion imaging and 201 Tl re-injection imaging to detect viable myocardium so that authors can enhance the image quality and shorten the examination time. Method: 34 OMI patients took the 99m Tc-MIBI and 201 Tl dual-isotope myocardium perfusion imaging and 201 Tl re-injection imaging respectively in two weeks. During the peak of normal dipyridamole stress i.v. 201 Tl 100 MBq was given and myocardium imaging was taken 15 min later. The dual-isotope group was given nitroglycerin 1mg under the tongue. Five min later, i.v. 99m Tc-MIBI 1110 mBq was given. In 201 Tl re-injection group i.v. 201 Tl 40 MBq was given 4 hour later and were imaged. Among the 34 OMI patients, 19 patients undertook another 99m Tc-MIBI static imaging. Results: There are no obvious differences between nitroglycerin interventional dual-isotope myocardium perfusion imaging and 201 Tl re-injection imaging in detection rate of viable myocardium, χ 2 =0.823, p>0.25. But they have great difference in perfusion changed sectional myocardium absorb rate, t=2.73, p 2 =27.867, p 201 Tl re-injection imaging

  17. [The protective action of nimodipine on the ischemic myocardium].

    Science.gov (United States)

    Tsorin, I B; Kazanova, G V; Kirsanova, G Iu; Chirkova, E Iu; Chichkanov, G G

    1992-01-01

    The experiments with unconscious cats and dogs have demonstrated that the calcium antagonist nimodipine has a profound anti-ischemic property. The drug reduces the average value of ST-segment elevation in multiple epicardial ECG leads, during acute myocardial ischemia. Nimodipine maintains cardiac pump and contractile functions, elevates ATP levels in the arbitrarily intact and ischemic myocardium of the left ventricle during 40-min occlusion and 60-min reperfusion of the coronary artery. The protective action of the drug is unassociated with enhanced collateral coronary circulation.

  18. Recommendations to realise and interpret the scintigraphy of myocardium perfusion

    International Nuclear Information System (INIS)

    Manrique, A.; Marie, P.Y.

    2003-06-01

    The purpose of these recommendations is to help the physicians in the realization and the interpretation of the tomo-scintigraphies of myocardium perfusion, when this examination is made at the patients having a known or suspected coronary incapacity. These recommendations aim to encourage the practitioners (of nuclear medicine) to reflect and to discuss the procedures applied in their services. These procedures must be also adapted, in every service, to the peculiarities of the environment and to the experiment of each one. (N.C.)

  19. New perspectives in the treatment of damaged myocardium using autologous skeletal myoblasts

    International Nuclear Information System (INIS)

    Rigatelli, Gianluca; Rossini, Katia; Vindigni, Vincenzo; Mazzoleni, Francesco; Rigatelli, Giorgio; Carraro, Ugo

    2004-01-01

    Autologous skeletal myoblast transplantation may be used to ameliorate the healing process following myocardium infarct and, hopefully, cardiomyopathies. Despite successful animal experimentation, several issues need to be addressed in clinical settings, i.e., the impact of the delivery route, the extent of short- and long-term survival, and differentiation of the injected skeletal myoblasts. The authors offer some new hypotheses resulting from basic research, i.e., where and when to inject the myogenic cells, whatever their source, how to decrease new myofiber atrophy and improve their regeneration. Although these new hypotheses still need to be tested in humans, they may be decisive for future experimental studies and will lead to making endovascular cell implantation a more effective way to treat ischemic heart disease and failure

  20. Development of Bioartificial Myocardium Using Stem Cells and Nanobiotechnology Templates

    Directory of Open Access Journals (Sweden)

    Juan Carlos Chachques

    2011-01-01

    Full Text Available Cell-based regenerative therapy is undergoing experimental and clinical trials in cardiology, in order to limit the consequences of decreased contractile function and compliance of damaged ventricles following myocardial infarction. Over 1000 patients have been treated worldwide with cell-based procedures for myocardial regeneration. Cellular cardiomyoplasty seems to reduce the size and fibrosis of infarct scars, limit adverse postischemic remodelling, and improve diastolic function. The development of a bioartificial myocardium is a new challenge; in this approach, tissue-engineered procedures are associated with cell therapy. Organ decellularization for bioscaffolds fabrication is a new investigated concept. Nanomaterials are emerging as the main candidates to ensure the achievement of a proper instructive cellular niche with good drug release/administration properties. Investigating the electrophysiological properties of bioartificial myocardium is the challenging objective of future research, associating a multielectrode network to provide electrical stimulation could improve the coupling of grafted cells and scaffolds with host cardiomyocytes. In summary, until now stem cell transplantation has not achieved clear hemodynamic benefits for myocardial diseases. Supported by relevant scientific background, the development of myocardial tissue engineering may constitute a new avenue and hope for the treatment of myocardial diseases.

  1. Probability mapping of scarred myocardium using texture and intensity features in CMR images

    Science.gov (United States)

    2013-01-01

    Background The myocardium exhibits heterogeneous nature due to scarring after Myocardial Infarction (MI). In Cardiac Magnetic Resonance (CMR) imaging, Late Gadolinium (LG) contrast agent enhances the intensity of scarred area in the myocardium. Methods In this paper, we propose a probability mapping technique using Texture and Intensity features to describe heterogeneous nature of the scarred myocardium in Cardiac Magnetic Resonance (CMR) images after Myocardial Infarction (MI). Scarred tissue and non-scarred tissue are represented with high and low probabilities, respectively. Intermediate values possibly indicate areas where the scarred and healthy tissues are interwoven. The probability map of scarred myocardium is calculated by using a probability function based on Bayes rule. Any set of features can be used in the probability function. Results In the present study, we demonstrate the use of two different types of features. One is based on the mean intensity of pixel and the other on underlying texture information of the scarred and non-scarred myocardium. Examples of probability maps computed using the mean intensity of pixel and the underlying texture information are presented. We hypothesize that the probability mapping of myocardium offers alternate visualization, possibly showing the details with physiological significance difficult to detect visually in the original CMR image. Conclusion The probability mapping obtained from the two features provides a way to define different cardiac segments which offer a way to identify areas in the myocardium of diagnostic importance (like core and border areas in scarred myocardium). PMID:24053280

  2. Protective Effect of Ischemic Postconditioning against Ischemia Reperfusion-Induced Myocardium Oxidative Injury in IR Rats

    Directory of Open Access Journals (Sweden)

    Jiangwei Ma

    2012-03-01

    Full Text Available Brief episodes of myocardial ischemia-reperfusion (IR employed during reperfusion after a prolonged ischemic insult may attenuate the total ischemia-reperfusion injury. This phenomenon has been termed ischemic postconditioning. In the present study, we studied the possible effect of ischemic postconditioning on an ischemic reperfusion (IR-induced myocardium oxidative injury in rat model. Results showed that ischemic postconditioning could improve arrhythmia cordis, reduce myocardium infarction and serum creatin kinase (CK, lactate dehydrogenase (LDH and aspartate transaminase (AST activities in IR rats. In addition, ischemic postconditioning could still decrease myocardium malondialdehyde (MDA level, and increased myocardium Na+-K+-ATPase, Ca2+-Mg2+-ATPase, superoxide dismutase (SOD, catalase (CAT, glutathione peroxidase (GSH-Px and glutathione reductase (GR activities. It can be concluded that ischemic postconditioning possesses strong protective effects against ischemia reperfusion-induced myocardium oxidative injury in IR rats.

  3. Cryoballoon Ablation for Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Jason G. Andrade, MD

    2012-03-01

    Full Text Available Focal point-by-point radiofrequency catheter ablation has shown considerable success in the treatment of paroxysmal atrial fibrillation. However, it is not without limitations. Recent clinical and preclinical studies have demonstrated that cryothermal ablation using a balloon catheter (Artic Front©, Medtronic CryoCath LP provides an effective alternative strategy to treating atrial fibrillation. The objective of this article is to review efficacy and safety data surrounding cryoballoon ablation for paroxysmal and persistent atrial fibrillation. In addition, a practical step-by-step approach to cryoballoon ablation is presented, while highlighting relevant literature regarding: 1 the rationale for adjunctive imaging, 2 selection of an appropriate cryoballoon size, 3 predictors of efficacy, 4 advanced trouble-shooting techniques, and 5 strategies to reduce procedural complications, such as phrenic nerve palsy.

  4. Total and interatrial epicardial adipose tissues are independently associated with left atrial remodeling in patients with atrial fibrillation.

    Science.gov (United States)

    Shin, Seung Yong; Yong, Hwan Seok; Lim, Hong Euy; Na, Jin Oh; Choi, Cheol Ung; Choi, Jong Il; Kim, Seong Hwan; Kim, Jin Won; Kim, Eung Ju; Park, Sang Weon; Rha, Seung-Woon; Park, Chang Gyu; Seo, Hong Seog; Oh, Dong Joo; Kim, Young-Hoon

    2011-06-01

    As epicardial adipose tissue (EAT) is a metabolically active visceral fat, potential interaction between EAT and myocardium is strongly suggested. The aims of this study were to determine whether the amount and regional distribution of EAT are related to the chronicity of atrial fibrillation (AF) and left atrial (LA) remodeling. This study consisted of 40 subjects with paroxysmal AF (PAF) and 40 with persistent AF (PeAF). Eighty subjects with no history of AF were enrolled as controls. Total volume of EAT (EAT(total)), regional thickness of EAT, and LA volume (LAV) were measured by multislice computed tomography. In the AF group, blood samples were drawn from coronary sinus for analysis of inflammatory cytokines including adiponectin. Compared with controls, AF subjects had larger LAV, EAT(total), and the thicknesses of periatrial EAT including interatrial septum (IAS). However, the thicknesses of periventricular EAT were not different between the groups. The PeAF subjects had larger LAV, EAT(total), and periatrial EAT thicknesses, higher levels of inflammatory cytokines, and lower level of adiponectin than did the PAF subjects. Adiponection level was significantly associated with EAT(total) and IAS thickness. Multivariate analysis revealed that EAT(total) (P = 0.004) and IAS thickness (P = 0.016) were independently associated with LAV. EAT(total) and thickness of periatrial EAT were significantly larger in AF subjects compared to those of the matched controls and were closely related to the chronicity of AF. Moreover, EAT(total) and IAS thickness were independently associated with LAV in subjects with AF. © 2011 Wiley Periodicals, Inc.

  5. 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.

  6. Temperature dependence of the kinetics of isometric myocardium relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Izakov, V.Ya.; Bykov, B.L.; Kimmelman, I.Ya.

    1981-11-01

    The dependence of the exponential decay constant expressing the isometric relaxation of the myocardium on temperature is investigated in animals with various specific contents of myocardial sarcoplasmic reticulum. Experiments were performed on cardiac ventricles and atria isolated from rabbits, frogs and turtles and electrically stimulated to produce maximal contraction at temperatures from 10 to 35 C. Arrhenius plots derived from the data are found to be linear in the myocardia of the rabbit and frog, with a greater activation energy for the relaxation found in the rabbit. The Arrhenius plot for the turtle, which has a sarcoplasmic reticulum content intermediate between those of the frog and rabbit, corresponds to two straight lines with different activation energies. Results thus support the hypothesis of two separate mechanisms of calcium removal, involving the sarcoplasmic reticulum and cellular membrane, in muscle relaxation.

  7. Radionuclide imaging in primary and secondary disorders of the myocardium

    International Nuclear Information System (INIS)

    Follansbee, W.P.

    1987-01-01

    The list of all potential causes of myocardial disease or injury is an extensive one: a condensed version is presented. Conceptually these processes can be categorized into those which are, or appear to be, primary to the myocardium and those which secondarily involve it. Nuclear imaging procedures, particularly those used to assess ventricular function, are in a general sense potentially applicable to the clinical evaluation of any of these entities. In certain of these conditions, however, nuclear cardiac procedures have a demonstrated or potential additional and more specific role for the diagnosis and quantification of the entity. A number of these, including coronary artery disease, valvular heart disease, cor pulmonale, and myocardial trauma, are the topics of other chapters and, therefore, are not dealt with further here. The remainder of the myocardial disorders in which nuclear imaging procedures have a recognized or potential specific role are the focus of this discussion

  8. Vernakalant selectively prolongs atrial refractoriness with no effect on ventricular refractoriness or defibrillation threshold in pigs.

    Science.gov (United States)

    Bechard, Jeff; Gibson, John Ken; Killingsworth, Cheryl R; Wheeler, Jeffery J; Schneidkraut, Marlowe J; Huang, Jian; Ideker, Raymond E; McAfee, Donald A

    2011-03-01

    Vernakalant is a novel antiarrhythmic agent that has demonstrated clinical efficacy for the treatment of atrial fibrillation. Vernakalant blocks, to various degrees, cardiac sodium and potassium channels with a pattern that suggests atrial selectivity. We hypothesized, therefore, that vernakalant would affect atrial more than ventricular effective refractory period (ERP) and have little or no effect on ventricular defibrillation threshold (DFT). Atrial and ventricular ERP and ventricular DFT were determined before and after treatment with vernakalant or vehicle in 23 anesthetized male mixed-breed pigs. Vernakalant was infused at a rate designed to achieve stable plasma levels similar to those in human clinical trials. Atrial and ventricular ERP were determined by endocardial extrastimuli delivered to the right atria or right ventricle. Defibrillation was achieved using external biphasic shocks delivered through adhesive defibrillation patches placed on the thorax after 10 seconds of electrically induced ventricular fibrillation. The DFT was estimated using the Dixon "up-and-down" method. Vernakalant significantly increased atrial ERP compared with vehicle controls (34 ± 8 versus 9 ± 7 msec, respectively) without significantly affecting ventricular ERP or DFT. This is consistent with atrial selective actions and supports the conclusion that vernakalant does not alter the efficacy of electrical defibrillation.

  9. Relaxin reduces susceptibility to post-infarct atrial fibrillation in mice due to anti-fibrotic and anti-inflammatory properties.

    Science.gov (United States)

    Beiert, Thomas; Tiyerili, Vedat; Knappe, Vincent; Effelsberg, Verena; Linhart, Markus; Stöckigt, Florian; Klein, Sabine; Schierwagen, Robert; Trebicka, Jonel; Nickenig, Georg; Schrickel, Jan W; Andrié, René P

    2017-08-26

    Relaxin-2 (RLX) is a peptide hormone that exerts beneficial anti-fibrotic and anti-inflammatory effects in diverse models of cardiovascular disease. The goal of this study was to determine the effects of RLX treatment on the susceptibility to atrial fibrillation (AF) after myocardial infarction (MI). Mice with cryoinfarction of the left anterior ventricular wall were treated for two weeks with either RLX (75 μg/kg/d) or vehicle (sodium acetate) delivered via subcutaneously implanted osmotic minipumps. RLX treatment significantly attenuated the increase in AF-inducibility following cryoinfarction and reduced the mean duration of AF episodes. Furthermore, epicardial mapping of both atria revealed an increase in conduction velocity. In addition to an attenuation of atrial hypertrophy, chronic application of RLX reduced atrial fibrosis, which was linked to a significant reduction in atrial mRNA expression of connective tissue growth factor. Transcript levels of the pro-inflammatory cytokines interleukin-6 and interleukin-1β were reduced in RLX treated mice, but macrophage infiltration into atrial myocardium was similar in the vehicle and RLX treated groups. Treatment with RLX in mice after MI reduces susceptibility to AF due to anti-inflammatory and anti-fibrotic properties. Because to these favorable actions, RLX may become a new therapeutic option in the treatment of AF, even when complicating MI. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Stroke prevention in atrial fibrillation

    DEFF Research Database (Denmark)

    Fanaroff, Alexander C; Steffel, Jan; Alexander, John H

    2018-01-01

    of anticoagulation for atrial fibrillation (AF). Observational studies employing RWD are useful for describing how oral anticoagulants are used in clinical practice, but generally cannot be used to make claims regarding comparative treatment effects. Questions regarding treatment effect generally are best answered...

  11. 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.

  12. Impaired atrial electromechanical function and atrial fibrillation promotion in alloxan-induced diabetic rabbits.

    Science.gov (United States)

    Fu, Huaying; Liu, Changle; Li, Jian; Zhou, Changyu; Cheng, Lijun; Liu, Tong; Li, Guangping

    2013-01-01

    Diabetes mellitus (DM) is an independent risk factor for atrial fibrillation (AF). However, the underlying mechanisms are still not clearly elucidated. The aim of this study was to evaluate the atrial electromechanical function, atrial electrophysiological changes and AF inducibility in alloxan-induced diabetic rabbits. In 8 alloxan-induced diabetic rabbits and 8 controls, we evaluated atrial electromechanical function by tissue Doppler imaging. Isolated Langendorff-perfused rabbit hearts were prepared to measure atrial refractory effective period (AERP) and its dispersion (AERPD), interatrial conduction time (IACT) and vulnerability to AF. Atrial interstitial fibrosis was evaluated by Sirius-Red staining. Compared with controls, left atrial lateral wall Pa'-start interval (Pastart) and right atrial wall Pastart were increased in diabetic rabbits. AERPD was increased and IACT was prolonged in diabetic rabbits. Inducibility of AF in diabetic group was significant higher than controls (6/8 vs. 1/8, p TEMA); left atrial lateral wall Papeak and TEMA, left atrial posterior wall TEMA, and IACT were correlated with atrial areas of fibrosis. Atrial electromechanical function is impaired in diabetic rabbits, and is associated with atrial fibrosis and interatrial electrical conduction delay.

  13. Diagnosis of Non-compacted Myocardium of the Left Ventricle in Children

    Directory of Open Access Journals (Sweden)

    I.B. Yershova

    2014-05-01

    Full Text Available The authors presented a review of published literature data on rare congenital abnormalities in children — a non-compacted myocardium of the left ventricle, which refers to unclassified cardiomyopathy. This pathology by the American Heart Association classification relates to genetic cardiomyopathy. Non-compacted myocardium of the left ventricle in children develops due to violation of myocardial induration of the fetus in utero. Diagnosis of the disease is difficult due to the lack of specific clinical signs. The authors also presented a clinical case of non-compacted left ventricular myocardium in 6-year-old girl.

  14. Analysis of the influence factors on myocardium to liver ratio of 99Tcm-MIBI

    International Nuclear Information System (INIS)

    Zhang Jinming; Tian Jiahe; Zhao Xiaoguang; Liu Zilai; Wang Shengcai

    1995-01-01

    The resting myocardial SPECT by different MIBI kits for 113 cases of normal and ischemic heart disease is performed. The preparation of kits, reducing agents, and the time of imaging are checked using myocardium to liver (M/L) ratio as the parameter of myocardium uptake of MIBI. It shows that MIBI uptake of myocardium has no relation with the reducing agents, the time of imaging between 60-120 min, while M/L ratio varied in every individual case. The ratio of M/L has also no relation to the Radiochemical Purity (RCP) as long as RCP is more than 95%

  15. Management of atrial fibrillation in the setting of heart failure

    NARCIS (Netherlands)

    Crijns, HJGM; VandenBerg, MP; VanGelder, IC; VanVeldhuisen, DJ

    Heart failure is often complicated by atrial fibrillation. Once atrial fibrillation has started it further enhances heart failure due to uncontrolled rate with shortened filling time and provocation of tachycardiomyopathy. Absent atrial kick and irregularity of the ventricular rhythm also

  16. 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...

  17. [Relations between FANS, PPI and atrial fibrillation].

    Science.gov (United States)

    Ricci, Fabrizio; De Caterina, Raffaele

    2013-05-01

    Recent evidence supports the existence of an association between the use of non-steroidal anti-inflammatory drugs and the risk of atrial fibrillation. Anti-inflammatory drugs are widely used for the treatment of systemic inflammatory disorders, and chronic inflammation is a well-known risk factor for the development of myocardial fibrosis. The latter accounts for atrial inhomogeneities of conduction, thus triggering and perpetuating atrial fibrillation. Atrial inflammatory remodeling may therefore be responsible for the higher incidence of atrial fibrillation among patients assuming steroidal and non-steroidal anti-inflammatory drugs because of an underlying inflammatory disorders. Alternative theories contemplate gastroesophageal reflux, which is extremely common during the use of non-steroidal anti-inflammatory drugs and may trigger atrial fibrillation, as mediating the above-mentioned association.

  18. Surgical treatment for ectopic atrial tachycardia.

    Science.gov (United States)

    Graffigna, A; Vigano, M; Pagani, F; Salerno, G

    1992-08-01

    Atrial tachycardia is an infrequent but potentially dangerous arrhythmia which often determines cardiac enlargement. Surgical ablation of the arrhythmia is effective and safe, provided a careful atrial mapping is performed and the surgical technique is tailored to the individual focus location. Eight patients underwent surgical ablation of ectopic atrial tachycardia between 1977 and 1990. Different techniques were adopted for each patient according to the anatomical location of the focus and possibly associated arrhythmias. Whenever possible, a closed heart procedure was chosen. In 1 patient a double focal origin was found and treated by separate procedures. In 1 patient with ostium secundum atrial septal defect and atrial flutter, surgical isolation of the right appendage and the ectopic focus was performed. In all patients ectopic atrial tachycardia was ablated with maintenance of the sinoatrial and atrioventricular nodal function as well as internodal conduction. In follow-up up to December 1991, no recurrency was recorded.

  19. 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.

  20. 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 fibrillati...

  1. Improved identification of viable myocardium using second harmonic imaging during dobutamine stress echocardiography

    NARCIS (Netherlands)

    F. Sozzi (Fabiola); D. Poldermans (Don); J.J. Bax (Jeroen); A. Elhendy (Abdou); E.C. Vourvouri (Eleni); R. Valkema (Roelf); J. de Sutter; A.F.L. Schinkel (Arend); A. Borghetti; J.R.T.C. Roelandt (Jos)

    2001-01-01

    textabstractOBJECTIVE: To determine whether, compared with fundamental imaging, second harmonic imaging can improve the accuracy of dobutamine stress echocardiography for identifying viable myocardium, using nuclear imaging as a reference. PATIENTS: 30 patients with chronic left

  2. Clinical usefulness of cardiac cine magnetic resonance imaging in patients with atrial fibrillation

    Energy Technology Data Exchange (ETDEWEB)

    Sakakura, Kazuyoshi; Anno, Hirofumi; Kondo, Takeshi [Fujita Health Univ., Toyoake, Aichi (Japan); and others

    1993-05-01

    We studied the clinical usefulness of cine mode magnetic resonance (MR) imaging in patients with atrial fibrillation (AF) from aspects of image quality and cardiac function. The signal-to-noise (S/N) ratio in the myocardium was significantly (p<0.05) lower in patients with AF than those with normal sinus rhythm. Two radiologists who did not know any patient's information evaluated the image quality visually by marking method on a scale of 12 points. There was no difference of image quality between the two groups. The standard deviation of R-R interval was significantly (r=-0.92, p<0.001) correlated with the S/N ratio in myocardium. Consequently, it was not favorable to estimate visually cardiac cine MR image in patients with AF, when standard deviation of R-R interval was large. The left ventricular (LV) end diastolic, end systolic and stroke volumes and ejection fraction were closely (r=0.82[approx]0.95, p<0.05[approx]0.001) correlated between MR imaging and M-mode echocardiography, respectively. The ability to detect left side valvular regurgitation was almost equal in both MR imaging and color Doppler echocardiography. This result was coincided to previous papers in patients with normal sinus rhythm. In conclusion, cine mode MR imaging was also useful to analyze cardiac function and detect valvular regurgitation in patients with AF. (author).

  3. Pathological mechanism for delayed hyperenhancement of chronic scarred myocardium in contrast agent enhanced magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Jian Wang

    Full Text Available OBJECTIVES: To evaluate possible mechanism for delayed hyperenhancement of scarred myocardium by investigating the relationship of contrast agent (CA first pass and delayed enhancement patterns with histopathological changes. MATERIALS AND METHODS: Eighteen pigs underwent 4 weeks ligation of 1 or 2 diagonal coronary arteries to induce chronic infarction. The hearts were then removed and perfused in a Langendorff apparatus. The hearts firstly experienced phosphorus 31 MR spectroscopy. The hearts in group I (n = 9 and II (n = 9 then received the bolus injection of Gadolinium diethylenetriamine pentaacetic acid (0.05 mmol/kg and gadolinium-based macromolecular agent (P792, 15 µmol/kg, respectively. First pass T2* MRI was acquired using a gradient echo sequence. Delayed enhanced T1 MRI was acquired with an inversion recovery sequence. Masson's trichrome and anti- von Willebrand Factor (vWF staining were performed for infarct characterization. RESULTS: Wash-in of both kinds of CA caused the sharp and dramatic T2* signal decrease of scarred myocardium similar to that of normal myocardium. Myocardial blood flow and microvessel density were significantly recovered in 4-week-old scar tissue. Steady state distribution volume (ΔR1 relaxation rate of Gd-DTPA was markedly higher in scarred myocardium than in normal myocardium, whereas ΔR1 relaxation rate of P792 did not differ significantly between scarred and normal myocardium. The ratio of extracellular volume to the total water volume was significantly greater in scarred myocardium than in normal myocardium. Scarred myocardium contained massive residual capillaries and dilated vessels. Histological stains indicated the extensively discrete matrix deposition and lack of cellular structure in scarred myocardium. CONCLUSIONS: Collateral circulation formation and residual vessel effectively delivered CA into scarred myocardium. However, residual vessel without abnormal hyperpermeability allowed Gd

  4. Probing myocardium biomechanics using quantitative optical coherence elastography

    Science.gov (United States)

    Wang, Shang; Lopez, Andrew L.; Morikawa, Yuka; Tao, Ge; Li, Jiasong; Larina, Irina V.; Martin, James F.; Larin, Kirill V.

    2015-03-01

    We present a quantitative optical coherence elastographic method for noncontact assessment of the myocardium elasticity. The method is based on shear wave imaging optical coherence tomography (SWI-OCT), where a focused air-puff system is used to induce localized tissue deformation through a low-pressure short-duration air stream and a phase-sensitive OCT system is utilized to monitor the propagation of the induced tissue displacement with nanoscale sensitivity. The 1-D scanning of M-mode OCT imaging and the application of optical phase retrieval and mapping techniques enable the reconstruction and visualization of 2-D depth-resolved shear wave propagation in tissue with ultra-high frame rate. The feasibility of this method in quantitative elasticity measurement is demonstrated on tissue-mimicking phantoms with the estimated Young's modulus compared with uniaxial compression tests. We also performed pilot experiments on ex vivo mouse cardiac muscle tissues with normal and genetically altered cardiomyocytes. Our results indicate this noncontact quantitative optical coherence elastographic method can be a useful tool for the cardiac muscle research and studies.

  5. Stereological Cell Morphometry In Right Atrium Myocardium Of Primates

    Science.gov (United States)

    Mandarim-De-Lacerda, Carlos A...; Hureau, Jacques

    1986-07-01

    The mechanism by which the cardiac impulse is propagated in normal hearts from its origin in the sinus node to the atrio-ventricular node has not been agreed on fully. We studied the "internodal posterior tract" through the crista terminalis by light microscopy and stereological morphometry. The hearts of 12 Papio cynocephalus were perfused , after sacrifice,with phosphate-buffered formol saline. The regions of the crista terminalis (CT), interatrial septum (IAS), atrioventricular bundle (AVB) and interventricular septum (IVS) were cut off and embedded in paraplast and sectioned (10 4m). The multipurpose test system M 42 was superimposed over the photomicrographs (1,890 points test, ESR = 2%) to the stereological computing. The quantitative results show that the cells from CT were more closely relationed with IAS cells than others cells (IVS and AVB cells). This results are not a morphological evidence to establish the specificity of the "internodal posterior tract". The cellular arrangement and anatomical variation in CT myocardium is very important.

  6. The myocardium functional reserve indicators in junior children with recurrent acute upper respiratory tract infection

    Directory of Open Access Journals (Sweden)

    L.S. Ovcharenko

    2017-02-01

    Full Text Available Background. The problem of early diagnosis of cardiovascular diseases in children is relevant throughout the world and in Ukraine, as in childhood the health and quality of life of an adult are formed. The psychoemotional stress in junior children as well as increasingly complicating school curriculum, information overload with electronic gadgets, increased frequency of colds in children cause physical inactivity. In addition, infectious agents have a toxic effect on the myocardium, altering its functional state. All these together adversely affect the formation and development of the cardiovascular and respiratory systems of children. The aim was to study the functional reserve of the myocardium in junior children, depending on the frequency of upper respiratory tract infection (URTI. Materials and methods. The study examined 1109 children aged 6 to 9 years old. The URTI incidence was analyzed depending on the age. In the study, the children were divided into two groups. Group 1 consisted of the children with URTI — 210. Group 2 involved the children with occasional URTI — 899. Results. Among 210 surveyed children with upper respiratory infections 171 schoolboys (81.4 % had reduced functional reserve of the myocardium, which is consistent with findings from other studies. In children aged 7 and 9 years old, the number of reduced functional reserve of the myocardium varies from 70 to 82 % in seven-year children, among the schoolboys aged 6 and 8 years old the incidence of reduced functional reserve of the myocardium increased from 83 to 100 % in six-year children. Conclusions. Children with URTI have a reduced functional reserve of the myocardium. Children with episodic URTI have higher rates of functional reserve of the myocardium, therefore reducing the incidence of URTI will lead to the improvement of the myocardium functional state.

  7. [Panic disorder and atrial fibrillation].

    Science.gov (United States)

    Olazabal Eizaguirre, N; Chavez, R; González-Torres, M A; Gaviria, M

    2013-10-01

    This paper studies the relationship between atrial fibrillation and panic disorder. There are often doubts on the differential diagnosis in emergency services and general medical settings. Panic disorder prevalence rates have been found to be high in patients suffering from atrial fibrillation. Various studies have observed that patients diagnosed with anxiety disorders frequently have higher cardiovascular disease rates compared to the general population. Usually, patients suffering from panic disorder exhibit somatic complaints suggesting coronary disease, such as chest pain or palpitations. The aim is to make the correct diagnosis and treatment for these different illnesses, and to decrease the costs due to misdiagnosis. Copyright © 2012 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España. All rights reserved.

  8. Perfusion single photon emission computed tomography of myocardium with 99mTc-tetra-phosmine (Myoview)

    International Nuclear Information System (INIS)

    Khusainova, Sh.K.; Zholdybaj, Zh.; Potapov, A.V.; Karaev, O.S.; Akhmetova, G.R.

    2003-01-01

    The aim of the work is study of diagnostic valuation of myocardium scintigraphy with help of the 99m Tc-tetrophosmin, Myoview in determination of latent coronary blood-circulation destabilization in liquidators of the Chernobyl accident (LChA) and persons living in the Semipalatinsk test site (STS) region. The perfusion myocardium scintigraphy was made to 71 patients (5 women and 66 men) from those - 33 LChA and 37 - residents of STS region. The examination was carried out in 'ADAC Genesys Epic' apparatus (USA). Mean age of the patients was 46.3±2.3 years old. In the result of examination the left ventricle myocardium perfusion reduction on 30 % and more was revealed. The distribution of radiopharmaceutical by the myocardium parts were relatively proportional both with pharmacologic load (ATF, dipiridamol) and the rest in 48 (67.7 %) patients. So, the 99m Tc-tetrophosmin, Myoview pharmaceutical allows with high rate estimate the myocardium perfusion and get a high qualitative images, that permits to identify localization, character and distribution of myocardium perfusion reduction in the revealed areas. In the result of myocardine scintigraphy with the pharmacologic load trial conducting the both the latent coronary blood-circulation destabilization forms and the incoming ones were differentiated

  9. Atrial fibrillation after cardiac surgery

    Directory of Open Access Journals (Sweden)

    Nair Suresh

    2010-01-01

    Full Text Available Once considered as nothing more than a nuisance after cardiac surgery, the importance of postoperative atrial fibrillation (POAF has been realized in the last decade, primarily because of the morbidity associated with the condition. Numerous causative factors have been described without any single factor being singled out as the cause of this complication. POAF has been associated with stroke, renal failure and congestive heart failure, although it is difficult to state whether POAF is directly responsible for these complications. Guidelines have been formulated for prevention of POAF. However, very few cardiothoracic centers follow any form of protocol to prevent POAF. Routine use of prophylaxis would subject all patients to the side effects of anti-arrhythmic drugs, while only a minority of the patients do actually develop this problem postoperatively. Withdrawal of beta blockers in the postoperative period has been implicated as one of the major causes of POAF. Amiodarone, calcium channel blockers and a variety of other pharmacological agents have been used for the prevention of POAF. Atrial pacing is a non-pharmacological measure which has gained popularity in the prevention of POAF. There is considerable controversy regarding whether rate control is superior to rhythm control in the treatment of established atrial fibrillation (AF. Amiodarone plays a central role in both rate control and rhythm control in postoperative AF. Newer drugs like dronedarone and ranazoline are likely to come into the market in the coming years.

  10. Three-dimensional speckle tracking echocardiography allows detailed evaluation of left atrial function in hypertrophic cardiomyopathy--insights from the MAGYAR-Path Study.

    Science.gov (United States)

    Domsik, Péter; Kalapos, Anita; Chadaide, Számi; Sepp, Róbert; Hausinger, Péter; Forster, Tamás; Nemes, Attila

    2014-11-01

    Hypertrophic cardiomyopathy (HCM) represents a generalized myopathic process affecting both ventricular and atrial myocardium. Reduced left atrial (LA) function was demonstrated in HCM by different methods. Three-dimensional (3D) speckle tracking echocardiography (STE) has just been introduced for the evaluation of LA. This study was designed to compare 3DSTE-derived LA volumetric and strain parameters in HCM with healthy controls. The study comprised 23 consecutive HCM patients (mean age: 48.5 ± 15.1 years, 14 men). Their results were compared to 23 age- and gender-matched healthy controls. Complete two-dimensional Doppler echocardiography and 3DSTE have been performed in all cases. Calculated LA maximum (66.4 ± 20.4 mL vs. 36.0 ± 6.1 mL, P echocardiography allows detailed evaluation of LA (dys) function in HCM by volumetric and strain measurements. © 2014, Wiley Periodicals, Inc.

  11. Total plasma proANP increases with atrial dilatation in horses

    DEFF Research Database (Denmark)

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

    2015-01-01

    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...... 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...

  12. Changes in plasma atrial natriuretic factor in patients with idiopathic atrial fibrillation

    International Nuclear Information System (INIS)

    Du Tongxin; Xia Xiaojie; Qu Wei; Wang Shukui; Sun Junjiang

    2002-01-01

    To observe the changes in plasma atrial natriuretic factor (AFN) in patients with idiopathic atrial fibrillation and investigate its mechanism, plasma ANF, platelet count and hematocrit were detected in 21 cases with transient idiopathic atrial fibrillation (group A, A1 representing attack, while A2 termination), 28 with persistent idiopathic atrial fibrillation (group B), 27 suffered from rheumatic heart disease with mitral stenosis and persistent atrial fibrillation (group C), 32 with transient supraventricular tachycardia (group D) and 20 normal controls (group E). It was found that the level of ANF was significantly higher in patients with attacking transient idiopathic atrial fibrillation than that in group A2, D and E (P 0.05), while there was significant difference in hematocrit in group A1 compared with group A2, D, E (P < 0.01). It suggested that ANF and hematocrit play an important role in the attack of idiopathic atrial fibrillation

  13. Calcium signalling silencing in atrial fibrillation.

    Science.gov (United States)

    Greiser, Maura

    2017-06-15

    Subcellular calcium signalling silencing is a novel and distinct cellular and molecular adaptive response to rapid cardiac activation. Calcium signalling silencing develops during short-term sustained rapid atrial activation as seen clinically during paroxysmal atrial fibrillation (AF). It is the first 'anti-arrhythmic' adaptive response in the setting of AF and appears to counteract the maladaptive changes that lead to intracellular Ca 2+ signalling instability and Ca 2+ -based arrhythmogenicity. Calcium signalling silencing results in a failed propagation of the [Ca 2+ ] i signal to the myocyte centre both in patients with AF and in a rabbit model. This adaptive mechanism leads to a substantial reduction in the expression levels of calcium release channels (ryanodine receptors, RyR2) in the sarcoplasmic reticulum, and the frequency of Ca 2+ sparks and arrhythmogenic Ca 2+ waves remains low. Less Ca 2+ release per [Ca 2+ ] i transient, increased fast Ca 2+ buffering strength, shortened action potentials and reduced L-type Ca 2+ current contribute to a substantial reduction of intracellular [Na + ]. These features of Ca 2+ signalling silencing are distinct and in contrast to the changes attributed to Ca 2+ -based arrhythmogenicity. Some features of Ca 2+ signalling silencing prevail in human AF suggesting that the Ca 2+ signalling 'phenotype' in AF is a sum of Ca 2+ stabilizing (Ca 2+ signalling silencing) and Ca 2+ destabilizing (arrhythmogenic unstable Ca 2+ signalling) factors. Calcium signalling silencing is a part of the mechanisms that contribute to the natural progression of AF and may limit the role of Ca 2+ -based arrhythmogenicity after the onset of AF. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

  14. Fiber architecture in remodeled myocardium revealed with a quantitative diffusion CMR tractography framework and histological validation.

    Science.gov (United States)

    Mekkaoui, Choukri; Huang, Shuning; Chen, Howard H; Dai, Guangping; Reese, Timothy G; Kostis, William J; Thiagalingam, Aravinda; Maurovich-Horvat, Pal; Ruskin, Jeremy N; Hoffmann, Udo; Jackowski, Marcel P; Sosnovik, David E

    2012-10-12

    The study of myofiber reorganization in the remote zone after myocardial infarction has been performed in 2D. Microstructural reorganization in remodeled hearts, however, can only be fully appreciated by considering myofibers as continuous 3D entities. The aim of this study was therefore to develop a technique for quantitative 3D diffusion CMR tractography of the heart, and to apply this method to quantify fiber architecture in the remote zone of remodeled hearts. Diffusion Tensor CMR of normal human, sheep, and rat hearts, as well as infarcted sheep hearts was performed ex vivo. Fiber tracts were generated with a fourth-order Runge-Kutta integration technique and classified statistically by the median, mean, maximum, or minimum helix angle (HA) along the tract. An index of tract coherence was derived from the relationship between these HA statistics. Histological validation was performed using phase-contrast microscopy. In normal hearts, the subendocardial and subepicardial myofibers had a positive and negative HA, respectively, forming a symmetric distribution around the midmyocardium. However, in the remote zone of the infarcted hearts, a significant positive shift in HA was observed. The ratio between negative and positive HA variance was reduced from 0.96 ± 0.16 in normal hearts to 0.22 ± 0.08 in the remote zone of the remodeled hearts (p layers of the myocardium. Tractography-based quantification, performed here for the first time in remodeled hearts, may provide a framework for assessing regional changes in the left ventricle following infarction.

  15. Acute Experimental Hyperthyroidism Does Not Affect Basal and Volume-Induced Atrial Natriuretic Peptide Secretion in Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Gregory Giamouzis

    2011-01-01

    Full Text Available Background. Excess circulating thyroid hormones are associated with increased cardiac atrial natriuretic peptide (ANP secretion but the exact mechanisms involved have not been fully elucidated in vivo. Methods. To examine whether thyroid hormone regulation of ANP secretion is the result of a direct action on the myocardium and/or of an indirect action through alterations in the peripheral circulation, plasma ANP levels (baseline and volume expansion-induced were evaluated in 14 healthy men, before and after triiodothyronine (T3 administration. Results. T3 administration was followed by a significant increase in serum T3 levels and a significant decrease in serum TSH levels, without significantly affecting ANP levels. Systemic vascular resistance, plasma rennin activity (PRA, and aldosterone (ALDO levels, as well as indices of left atrial function, were not significantly altered, despite a significant increase in cardiac output. Plasma volume expansion, induced by a 1500 ml normal saline (NSal infusion, both before and after T3 administration, was followed by a significant decrease in PRA and ALDO and a significant increase in plasma ANP levels, without significantly affecting the mean blood pressure (BP and heart rate (HR in each study period. The NSal-induced response, measured as the integrated area under the curve corrected for baseline values (-AUC, was not different after T3 administration for ANP, ALDO, PRA, HR, and mean BP. Conclusion. In vivo thyroid hormone-induced myocardial ANP secretion is the result of an indirect action mainly through hemodynamic changes that increase atrial stretch.

  16. Myocardial thallium-201 kinetics in normal and ischemic myocardium

    International Nuclear Information System (INIS)

    Grunwald, A.M.; Watson, D.D.; Holzgrefe, H.H. Jr.; Irving, J.F.; Beller, G.A.

    1981-01-01

    The net myocardial accumulation of thallium-201 after injection depends upon the net balance between continuing myocardial extraction from low levels of recirculating thallium in the blood compartment and the net rate of efflux of thallium from the myocardium into the extracardiac blood pool. These experiments were designed to measure separately the myocardial extraction and intrinsic myocardial efflux of thallium-201 at normal and at reduced rates of myocardial blood flow. The average myocardial extraction fraction at normal blood flow in 10 anesthetized dogs was 82 +/- 6% (+/- SD) at normal coronary arterial perfusion pressures and increased insignificantly, to 85 +/- 7%, at coronary perfusion pressures of 10--35 mm Hg. At normal coronary arterial perfusion pressures in 12 additional dogs, the intrinsic thallium washout in the absence of systemic recirculation had a half-time (T 1/2) of 54 +/- 7 minutes. The intrinsic cellular washout rate began to increase as distal perfusion pressures fell below 60 mm Hg and increased markedly to a T 1/2 of 300 minutes at perfusion pressures of 25--30 mm Hg. A second, more rapid component of intrinsic thallium washout (T 1/2 2.5 minutes) representing approximately 7% of the total initially extracted myocardial thallium was observed. The faster washout component is presumed to be due to washout of interstitial thallium unextracted by myocardial cells, whereas the slower component is presumed due to intracellular washout. The net clearance time of thallium measured after i.v. injection is much longer than the intrinsic myocardial cellular washout rate because of continuous replacement of myocardial thallium from systemic recirculation. Myocardial redistribution of thallium-201 in states of chronically reduced perfusion cannot be the result of increased myocardial extraction efficiency, but rather, is the result of the slower intrinsic cellular washout rate at reduced perfusion levels

  17. Synaptic Plasticity in Cardiac Innervation and Its Potential Role in Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Jesse L. Ashton

    2018-03-01

    Full Text Available Synaptic plasticity is defined as the ability of synapses to change their strength of transmission. Plasticity of synaptic connections in the brain is a major focus of neuroscience research, as it is the primary mechanism underpinning learning and memory. Beyond the brain however, plasticity in peripheral neurons is less well understood, particularly in the neurons innervating the heart. The atria receive rich innervation from the autonomic branch of the peripheral nervous system. Sympathetic neurons are clustered in stellate and cervical ganglia alongside the spinal cord and extend fibers to the heart directly innervating the myocardium. These neurons are major drivers of hyperactive sympathetic activity observed in heart disease, ventricular arrhythmias, and sudden cardiac death. Both pre- and postsynaptic changes have been observed to occur at synapses formed by sympathetic ganglion neurons, suggesting that plasticity at sympathetic neuro-cardiac synapses is a major contributor to arrhythmias. Less is known about the plasticity in parasympathetic neurons located in clusters on the heart surface. These neuronal clusters, termed ganglionated plexi, or “little brains,” can independently modulate neural control of the heart and stimulation that enhances their excitability can induce arrhythmia such as atrial fibrillation. The ability of these neurons to alter parasympathetic activity suggests that plasticity may indeed occur at the synapses formed on and by ganglionated plexi neurons. Such changes may not only fine-tune autonomic innervation of the heart, but could also be a source of maladaptive plasticity during atrial fibrillation.

  18. [Typical atrial flutter: Diagnosis and therapy].

    Science.gov (United States)

    Thomas, Dierk; Eckardt, Lars; Estner, Heidi L; Kuniss, Malte; Meyer, Christian; Neuberger, Hans-Ruprecht; Sommer, Philipp; Steven, Daniel; Voss, Frederik; Bonnemeier, Hendrik

    2016-03-01

    Typical, cavotricuspid-dependent atrial flutter is the most common atrial macroreentry tachycardia. The incidence of atrial flutter (typical and atypical forms) is age-dependent with 5/100,000 in patients less than 50 years and approximately 600/100,000 in subjects > 80 years of age. Concomitant heart failure or pulmonary disease further increases the risk of typical atrial flutter.Patients with atrial flutter may present with symptoms of palpitations, reduced exercise capacity, chest pain, or dyspnea. The risk of thromboembolism is probably similar to atrial fibrillation; therefore, the same antithrombotic prophylaxis is required in atrial flutter patients. Acutely symptomatic cases may be subjected to cardioversion or pharmacologic rate control to relieve symptoms. Catheter ablation of the cavotricuspid isthmus represents the primary choice in long-term therapy, associated with high procedural success (> 97 %) and low complication rates (0.5 %).This article represents the third part of a manuscript series designed to improve professional education in the field of cardiac electrophysiology. Mechanistic and clinical characteristics as well as management of isthmus-dependent atrial flutter are described in detail. Electrophysiological findings and catheter ablation of the arrhythmia are highlighted.

  19. Atrial natriuretic peptide (ANP)-granules: ultrastructure ...

    African Journals Online (AJOL)

    ANP) are present in the four regions of the atrial-auricular complex (two atria and two auricles). ANP-immunoreactivity was detected in all granules from the four regions. Ultrastructurally, atrial myocytes show the presence of very electron dense ...

  20. Radiofrequency catheter oblation in atrial flutter

    International Nuclear Information System (INIS)

    Yan Ji; Wang Heping; Xu Jian; Liu Fuyuan; Fan Xizhen; An Chunsheng; Han Xiaoping; Ding Xiaomei; Wang Jiasheng; Gu Tongyuan

    2002-01-01

    Objective: To evaluate the radiofrequency catheter ablation for type I atrial flutter through application of Holo catheter labelling with anatomic imaging localization to ablate the isthmus of IVCTA during complete double-way block. Methods: Eleven cases with type I atrial flutter undergone Holo catheter labelling technique and consecution with conduction time change of coronary venous sinus orifice with-right atrial lower lateral wall pace excitation, were performed with radiofrequency catheter ablation for the isthmus outcoming with complete double-way conduction block. Results: All together 11 cases with 4 of atrial flutter and 7 of sinus rhythm were undergone radiofrequency catheter ablation resulting with double-way conduction block of the isthmus accompanied by prolongation of right atrial conduction time 56.0 ± 2.3 ms and 53.0 ± 4.6 ms respectively. The right atrial excitation appeared to be in clockwise and counter-clockwise of single direction. No recurrence occurred during 3-34 months follow up with only one showing atrial fibrillation. Conclusions: The application of Holo catheter labelling technique with anatomic imaging localization to achieve the double-way conduction block by radiofrequency catheter ablation of TVC-TA isthmus, is a reliable method for treating atrial flutter

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

    NARCIS (Netherlands)

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

    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

  2. Left Atrial 4D Blood Flow Dynamics and Hemostasis following Electrical Cardioversion of Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Merih Cibis

    2017-12-01

    Full Text Available Background: Electrical cardioversion in patients with atrial fibrillation is followed by a transiently impaired atrial mechanical function, termed atrial stunning. During atrial stunning, a retained risk of left atrial thrombus formation exists, which may be attributed to abnormal left atrial blood flow patterns. 4D Flow cardiovascular magnetic resonance (CMR enables blood flow assessment from the entire three-dimensional atrial volume throughout the cardiac cycle. We sought to investigate left atrial 4D blood flow patterns and hemostasis during left atrial stunning and after left atrial mechanical function was restored.Methods: 4D Flow and morphological CMR data as well as blood samples were collected in fourteen patients at two time-points: 2–3 h (Time-1 and 4 weeks (Time-2 following cardioversion. The volume of blood stasis and duration of blood stasis were calculated. In addition, hemostasis markers were analyzed.Results: From Time-1 to Time-2: Heart rate decreased (61 ± 7 vs. 56 ± 8 bpm, p = 0.01; Maximum change in left atrial volume increased (8 ± 4 vs. 22 ± 15%, p = 0.009; The duration of stasis (68 ± 11 vs. 57 ± 8%, p = 0.002 and the volume of stasis (14 ± 9 vs. 9 ± 7%, p = 0.04 decreased; Thrombin-antithrombin complex (TAT decreased (5.2 ± 3.3 vs. 3.3 ± 2.2 μg/L, p = 0.008. A significant correlation was found between TAT and the volume of stasis (r2 = 0.69, p < 0.001 at Time-1 and between TAT and the duration of stasis (r2 = 0.34, p = 0.04 at Time-2.Conclusion: In this longitudinal study, left atrial multidimensional blood flow was altered and blood stasis was elevated during left atrial stunning compared to the restored left atrial mechanical function. The coagulability of blood was also elevated during atrial stunning. The association between blood stasis and hypercoagulability proposes that assessment of left atrial 4D flow can add to the pathophysiological understanding of thrombus formation during atrial fibrillation

  3. Left Atrial 4D Blood Flow Dynamics and Hemostasis following Electrical Cardioversion of Atrial Fibrillation

    Science.gov (United States)

    Cibis, Merih; Lindahl, Tomas L.; Ebbers, Tino; Karlsson, Lars O.; Carlhäll, Carl-Johan

    2017-01-01

    Background: Electrical cardioversion in patients with atrial fibrillation is followed by a transiently impaired atrial mechanical function, termed atrial stunning. During atrial stunning, a retained risk of left atrial thrombus formation exists, which may be attributed to abnormal left atrial blood flow patterns. 4D Flow cardiovascular magnetic resonance (CMR) enables blood flow assessment from the entire three-dimensional atrial volume throughout the cardiac cycle. We sought to investigate left atrial 4D blood flow patterns and hemostasis during left atrial stunning and after left atrial mechanical function was restored. Methods: 4D Flow and morphological CMR data as well as blood samples were collected in fourteen patients at two time-points: 2–3 h (Time-1) and 4 weeks (Time-2) following cardioversion. The volume of blood stasis and duration of blood stasis were calculated. In addition, hemostasis markers were analyzed. Results: From Time-1 to Time-2: Heart rate decreased (61 ± 7 vs. 56 ± 8 bpm, p = 0.01); Maximum change in left atrial volume increased (8 ± 4 vs. 22 ± 15%, p = 0.009); The duration of stasis (68 ± 11 vs. 57 ± 8%, p = 0.002) and the volume of stasis (14 ± 9 vs. 9 ± 7%, p = 0.04) decreased; Thrombin-antithrombin complex (TAT) decreased (5.2 ± 3.3 vs. 3.3 ± 2.2 μg/L, p = 0.008). A significant correlation was found between TAT and the volume of stasis (r2 = 0.69, p < 0.001) at Time-1 and between TAT and the duration of stasis (r2 = 0.34, p = 0.04) at Time-2. Conclusion: In this longitudinal study, left atrial multidimensional blood flow was altered and blood stasis was elevated during left atrial stunning compared to the restored left atrial mechanical function. The coagulability of blood was also elevated during atrial stunning. The association between blood stasis and hypercoagulability proposes that assessment of left atrial 4D flow can add to the pathophysiological understanding of thrombus formation during atrial fibrillation related

  4. Isthmus Dependent Atrial Flutter Cycle Length Correlates with Right Atrial Cross-Sectional Area

    Directory of Open Access Journals (Sweden)

    Kousik Krishnan

    2009-05-01

    Full Text Available Background: Right atrial flutter cycle length can prolong in the presence of antiarrhythmic drug therapy. We hypothesized that the cycle length of right atrial isthmus dependent flutter would correlate with right atrial cross-sectional area measurements. Methods: 60 patients who underwent ablation for electrophysiologically proven isthmus dependent right atrial flutter, who were not on Class I or Class III antiarrhythmic drugs and had recent 2-dimensional echocardiographic data comprised the study group. Right atrial length and width were measured in the apical four chamber view. Cross-sectional area was estimated by multiplying the length and width. 35 patients had an atrial flutter rate ≥250 bpm (Normal Flutter Group and 25 patients had an atrial flutter rate < 250 bpm (Slow Flutter Group. Results: Mean atrial flutter rate was 283 bpm in the normal flutter group and 227 bpm in the slow flutter group. Mean atrial flutter cycle length was 213 ms in the Normal Flutter Group and 265 ms in the Slow Flutter Group (p<0.0001. Mean right atrial cross sectional area was 1845 mm2 in the Normal Flutter group and 2378 mm2 in the Slow Flutter Group, (p< 0.0001. Using linear regression, CSA was a significant predictor of cycle length (β =0.014 p = 0.0045. For every 1 mm2 increase in cross-sectional area, cycle length is 0.014 ms longer.Conclusion: In the absence of antiarrhythmic medications, right atrial cross sectional area enlargement correlates with atrial flutter cycle length. These findings provide further evidence that historical rate-related definitions of typical isthmus dependent right atrial are not mechanistically valid.

  5. [Left versus bi-atrial radiofrequency ablation in the treatment of atrial fibrillation].

    Science.gov (United States)

    Wang, Jian-Gang; Meng, Xu; Li, Hui

    2008-11-25

    To evaluate the effectiveness of radiofrequency modified maze operation for the treatment of atrial fibrillation (AF) and compare the results of the left versus bi-atrial procedures. 305 patients of organic heart disease combined with AF, 117 males and 188 females, aged (53 +/- 10), that underwent cardiac valve operation (n = 293) and/or coronary artery bypass graft surgery (n = 14), received concomitant atrial fibrillation, bi-atrial (n = 160) or left atrial (n = 145) with a mean duration of (36 +/- 43) months. Follow-up was conducted for (28 +/- 5) (3 - 42) months. Thirteen patients (4.3%) died postoperatively: 7 died of multisystem and organ failure, 3 of low cardiac output, 1 of rupture of left ventricle, 1 of arrhythmia, and 1 of sudden death. During the follow-up, 1 patient died of heart failure, 1 of encephalorrhagia and 1 of unknown reason in the bi-atrial group. At the end of the procedure 223 patients (73.1%) had sinus rhythm, with a sinus rhythm rate of 66.9% (107/160) in the bi-atrial group, significant lower than that in the left atrial group (80.0%, 116/145, P bi-atrial group was 80.0%, not significantly different from that of the left atrial group (81.9%, P > 0.05). The Kaplan-Meier survival analysis showed there was no significant difference in the AF rhythm rate between these 2 groups (P = 0.33). Logistic regression analysis showed that the left atrial diameter of >/= 80 mm was an independent predictor of AF recurrence. Both the left and bi-atrial procedures are successful in terms of restoring sinus rhythm. Left atrial ablation in severe cases and where the incision of right atrium is not needed is a reasonable choice.

  6. Compromised redox homeostasis, altered nitroso-redox balance, and therapeutic possibilities in atrial fibrillation.

    Science.gov (United States)

    Simon, Jillian N; Ziberna, Klemen; Casadei, Barbara

    2016-04-01

    Although the initiation, development, and maintenance of atrial fibrillation (AF) have been linked to alterations in myocyte redox state, the field lacks a complete understanding of the impact these changes may have on cellular signalling, atrial electrophysiology, and disease progression. Recent studies demonstrate spatiotemporal changes in reactive oxygen species production shortly after the induction of AF in animal models with an uncoupling of nitric oxide synthase activity ensuing in the presence of long-standing persistent AF, ultimately leading to a major shift in nitroso-redox balance. However, it remains unclear which radical or non-radical species are primarily involved in the underlying mechanisms of AF or which proteins are targeted for redox modification. In most instances, only free radical oxygen species have been assessed; yet evidence from the redox signalling field suggests that non-radical species are more likely to regulate cellular processes. A wider appreciation for the distinction of these species and how both species may be involved in the development and maintenance of AF could impact treatment strategies. In this review, we summarize how redox second-messenger systems are regulated and discuss the recent evidence for alterations in redox regulation in the atrial myocardium in the presence of AF, while identifying some critical missing links. We also examine studies looking at antioxidants for the prevention and treatment of AF and propose alternative redox targets that may serve as superior therapeutic options for the treatment of AF. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Cardiology.

  7. Left-to-Right Atrial Inward Rectifier Potassium Current Gradients in Patients With Paroxysmal Versus Chronic Atrial Fibrillation

    Science.gov (United States)

    Voigt, Niels; Trausch, Anne; Knaut, Michael; Matschke, Klaus; Varró, András; Van Wagoner, David R.; Nattel, Stanley; Ravens, Ursula; Dobrev, Dobromir

    2018-01-01

    Background Recent evidence suggests that atrial fibrillation (AF) is maintained by high-frequency reentrant sources with a left-to-right–dominant frequency gradient, particularly in patients with paroxysmal AF (pAF). Unequal left-to-right distribution of inward rectifier K+ currents has been suggested to underlie this dominant frequency gradient, but this hypothesis has never been tested in humans. Methods and Results Currents were measured with whole-cell voltage-clamp in cardiomyocytes from right atrial (RA) and left (LA) atrial appendages of patients in sinus rhythm (SR) and patients with AF undergoing cardiac surgery. Western blot was used to quantify protein expression of IK1 (Kir2.1 and Kir2.3) and IK,ACh (Kir3.1 and Kir3.4) subunits. Basal current was ≈2-fold larger in chronic AF (cAF) versus SR patients, without RA-LA differences. In pAF, basal current was ≈2-fold larger in LA versus RA, indicating a left-to-right atrial gradient. In both atria, Kir2.1 expression was ≈2-fold greater in cAF but comparable in pAF versus SR. Kir2.3 levels were unchanged in cAF and RA-pAF but showed a 51% decrease in LA-pAF. In SR, carbachol-activated (2 μmol/L) IK,ACh was 70% larger in RA versus LA. This right-to-left atrial gradient was decreased in pAF and cAF caused by reduced IK,ACh in RA only. Similarly, in SR, Kir3.1 and Kir3.4 proteins were greater in RA versus LA and decreased in RA of pAF and cAF. Kir3.1 and Kir3.4 expression was unchanged in LA of pAF and cAF. Conclusions Our results support the hypothesis that a left-to-right gradient in inward rectifier background current contributes to high-frequency sources in LA that maintain pAF. These findings have potentially important implications for development of atrial-selective therapeutic approaches. PMID:20657029

  8. Cetirizine-Induced atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Altuğ Osken

    2016-01-01

    Full Text Available Atrial fibrillation (AF is the most common observed arrhythmia in clinical practice. In the literature, AF events associated with drug induction are available. Cetirizine is a second-generation histamine antagonist used in the treatment of allergies, angioedema, and urticaria. We wish to present an atypical case who took cetirizine medication for relieving symptoms of upper tract respiratory system infection, experienced rapid ventricular response AF and treated successfully. To best of our knowledge, this is the first case of cetirizine-induced AF.

  9. Anisotropy of the Elastic Properties of Normal and Pathological Myocardium: Angular Dependence of Ultrasonic Backscatter, Attenuation, and Velocity.

    Science.gov (United States)

    Verdonk, Edward Dennis

    The focus of this thesis is the measurement of anisotropies in the ultrasonic parameters of soft tissues. The goal is to contribute to a better understanding of the physics which underlies the interaction of ultrasonic waves with inhomogeneous and anisotropic media. Broadband measurements using a piezoelectric transducer are reported for investigations of excised specimens of human and canine myocardial tissue. Emphasis is placed on identifying the effect that the muscle fiber orientation, relative to the direction of insonification, has on the propagation and scattering properties of ultrasonic waves. Results of the anisotropy of backscatter, the anisotropy of attenuation, and the anisotropy of quasilongitudinal velocity are presented for data obtained in 2^ circ increments through the full 360 ^circ relative to the myofibers. Measured velocities are used in conjunction with measured specimen densities to determine the elastic stiffness constants c_{11} and c_ {33} and to estimate specific mechanical moduli for thin layers of myocardium.

  10. 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.

  11. Imaging gene expression in human mesenchymal stem cells: from small to large animals

    DEFF Research Database (Denmark)

    Willmann, Jürgen K; Paulmurugan, Ramasamy; Rodriguez-Porcel, Martin

    2009-01-01

    To evaluate the feasibility of reporter gene imaging in implanted human mesenchymal stem cells (MSCs) in porcine myocardium by using clinical positron emission tomography (PET)-computed tomography (CT) scanning.......To evaluate the feasibility of reporter gene imaging in implanted human mesenchymal stem cells (MSCs) in porcine myocardium by using clinical positron emission tomography (PET)-computed tomography (CT) scanning....

  12. 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...

  13. MRI in the diagnosis of non-compacted ventricular Myocardium (NCVM) compared to echocardiography

    International Nuclear Information System (INIS)

    Weiss, F.; Habermann, C.R.; Sievers, J.; Weil, J.; Adam, G.; Lilje, C.; Razek, W.

    2003-01-01

    Purpose: To report the detection of con-compacted ventricular myocardium (NVCM) with MRI compared to echocardiography in 8 patients. Material and methods: Non-compaction of the ventricular myocardium is a congenital disorder characterized by an altered structure of the myocardial wall resulting from an intrauterine arrest in endomyocardial embryogenesis. The morphological findings consist of a prominent meshwork of multiple myocardial trabeculations and deep intertrabecular recesses, communicating with the left ventricular cavity. 8 consecutive patients (mean age 7.3 years) with clinical and echocardiographic signs of NCVM were examined by MRI (1.5 T, Vision, Siemens) in short axis and 2- and 4-chamber views, using T 1 -weighted TSE and Cine-GRE in 6 patients and true FISP sequences in 2 patients. MRI and echocardiography were evaluated for visibility, signs of NCVM and involvement of myocardial wall segments. Thickness was measured for non-compacted and compacted myocardium and the non-compacted to compacted (N/C) ratio calculated. Results: MRI diagnosed 6 of 8 patients of having NCVM. Myocardial thickness as measured by echocardiography and MRI showed a good correlation in compacted myocardium (r = 0.82) and no correlation in non-compacted myocardium (r = 0.4). In 2 cases, non-compacted myocardium was detected, but echocardiography did not reach the N/C ratio > 2 as required to diagnose NCVM in accordance with the criteria found in the literature. Both patients were also misdiagnosed by MRI performed with Cine-GRE. MRI reached a N/C ratio > 2 in only three patients. Newer TruFisp sequences showed no definite advantages. Extent of non-compaction could be visualized correctly with MRI. (orig.) [de

  14. 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.

  15. 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. PMID:25489858

  16. 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 congenital 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.

  17. Free Radical Oxidation in Rat Myocardium after Maximum Permissible Hepatic Resection.

    Science.gov (United States)

    Ermolaev, P A; Khramykh, T P; Barskaya, L O

    2016-03-01

    Free radical oxidation in rat myocardial homogenate was studied by chemiluminescent assay during the early terms after maximum permissible liver resection. During this period, activation of free radical oxidation was biphasic. The critical terms characterized by dramatic intensification of free radical oxidation in the myocardium are the first hour and the first day after surgery. The period from 3 to 12 h after surgery, in which the indices of chemiluminescence decrease, can be tentatively termed as the period of "putative wellbeing". Normalization of the free radical oxidation processes in the myocardium occurred by day 7 after surgery.

  18. Statistical and fractal analysis of autofluorescent myocardium images in posthumous diagnostics of acute coronary insufficiency

    Science.gov (United States)

    Boichuk, T. M.; Bachinskiy, V. T.; Vanchuliak, O. Ya.; Minzer, O. P.; Garazdiuk, M.; Motrich, A. V.

    2014-08-01

    This research presents the results of investigation of laser polarization fluorescence of biological layers (histological sections of the myocardium). The polarized structure of autofluorescence imaging layers of biological tissues was detected and investigated. Proposed the model of describing the formation of polarization inhomogeneous of autofluorescence imaging biological optically anisotropic layers. On this basis, analytically and experimentally tested to justify the method of laser polarimetry autofluorescent. Analyzed the effectiveness of this method in the postmortem diagnosis of infarction. The objective criteria (statistical moments) of differentiation of autofluorescent images of histological sections myocardium were defined. The operational characteristics (sensitivity, specificity, accuracy) of these technique were determined.

  19. 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

  20. Fiber architecture in remodeled myocardium revealed with a quantitative diffusion CMR tractography framework and histological validation

    Directory of Open Access Journals (Sweden)

    Mekkaoui Choukri

    2012-10-01

    Full Text Available Abstract Background The study of myofiber reorganization in the remote zone after myocardial infarction has been performed in 2D. Microstructural reorganization in remodeled hearts, however, can only be fully appreciated by considering myofibers as continuous 3D entities. The aim of this study was therefore to develop a technique for quantitative 3D diffusion CMR tractography of the heart, and to apply this method to quantify fiber architecture in the remote zone of remodeled hearts. Methods Diffusion Tensor CMR of normal human, sheep, and rat hearts, as well as infarcted sheep hearts was performed ex vivo. Fiber tracts were generated with a fourth-order Runge-Kutta integration technique and classified statistically by the median, mean, maximum, or minimum helix angle (HA along the tract. An index of tract coherence was derived from the relationship between these HA statistics. Histological validation was performed using phase-contrast microscopy. Results In normal hearts, the subendocardial and subepicardial myofibers had a positive and negative HA, respectively, forming a symmetric distribution around the midmyocardium. However, in the remote zone of the infarcted hearts, a significant positive shift in HA was observed. The ratio between negative and positive HA variance was reduced from 0.96 ± 0.16 in normal hearts to 0.22 ± 0.08 in the remote zone of the remodeled hearts (p Conclusions A significant reorganization of the 3D fiber continuum is observed in the remote zone of remodeled hearts. The positive (rightward shift in HA in the remote zone is greatest in the subepicardium, but involves all layers of the myocardium. Tractography-based quantification, performed here for the first time in remodeled hearts, may provide a framework for assessing regional changes in the left ventricle following infarction.

  1. 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.

  2. Assessment of right atrial function analysis

    International Nuclear Information System (INIS)

    Shohgase, Takashi; Miyamoto, Atsushi; Kanamori, Katsushi; Kobayashi, Takeshi; Yasuda, Hisakazu

    1988-01-01

    To assess the potential utility of right atrial function analysis in cardiac disease, reservoir function, pump function, and right atrial peak emptying rate (RAPER) were compared in 10 normal subjects, 32 patients with coronary artery disease, and 4 patients with primary pulmonary hypertension. Right atrial volume curves were obtained using cardiac radionuclide method with Kr-81m. In normal subjects, reservoir function index was 0.41+-0.05; pump function index was 0.25+-0.05. Both types of patients has decreased reservoir funcion and increased pump function. Pump function tended to decrease with an increase of right ventricular end-diastolic pressure. RAPER correlated well with right ventricular peak filling rate, probably reflecting right ventricular diastolic function. Analysis of right atrial function seemed to be of value in evaluating factors regulating right ventricular contraction and diastolic function, and cardiac output. (Namekawa, K)

  3. Atrial natriuretic peptide (ANP)-granules: ultrastructure ...

    African Journals Online (AJOL)

    AJB SERVER

    2006-12-29

    Dec 29, 2006 ... morphometry and function. Eliane Florencio ... granules is greatest in the right atrium followed by the left atrium and left auricle and right auricle, in this order. ... family: Atrial natriuretic peptide (ANP), Urodilatin, Brain natriuretic ...

  4. Mr 40,000 and Mr 39,000 pertussis toxin substrates are increased in surgically denervated dog ventricular myocardium

    Energy Technology Data Exchange (ETDEWEB)

    Hershberger, R.E.; Feldman, A.M.; Anderson, F.L.; Kimball, J.A.; Wynn, J.R.; Bristow, M.R. (Univ. of Utah School of Medicine, Salt Lake City (USA))

    1991-04-01

    To test the general hypothesis that cardiac innervation may participate in myocardial G protein regulation, we examined the effects of complete intrapericardial surgical denervation or sham operation in dogs. In particulate fractions of dog left ventricular (LV) myocardium harvested 28-33 days after denervation or sham operation, Mr 40,000 and Mr 39,000 pertussis toxin-sensitive substrates (G proteins) were increased by 31% (1.31 +/- 0.084 vs 1.00 +/- 0.058 OD, arbitrary units, p less than 0.01) and 40% (1.40 +/- 0.117 vs. 1.000 +/- 0.084 OD, arbitrary units, p less than 0.02), respectively, as compared with sham-operated controls. The Mr 40,000 pertussis toxin-sensitive band comigrated with a pertussis toxin-sensitive substrate in human erythrocyte membranes known to contain an alpha Gi species. In these same preparations basal, GTP and GppNHp stimulated adenylate cyclase activities were decreased in denervated heart by 20, 26, and 19%, respectively, consistent with increased activity of an inhibitory G protein. In contrast, Gs function was not altered, because cyc(-) membranes reconstituted with membrane extracts and fluoride and beta-receptor-stimulated adenylate cyclase activity were not different between groups. Furthermore, adenylate cyclase catalytic subunit function as assessed with forskolin and manganese stimulation was not different between preparations of control and denervated heart. We conclude that in preparations of surgically denervated dog myocardium Mr 40,000 and Mr 39,000 pertussis toxin-sensitive G proteins are increased by 31 and 40%, respectively, and that functional alterations in adenylate cyclase activity exist, consistent with increased inhibitory G-protein function.

  5. Mr 40,000 and Mr 39,000 pertussis toxin substrates are increased in surgically denervated dog ventricular myocardium

    International Nuclear Information System (INIS)

    Hershberger, R.E.; Feldman, A.M.; Anderson, F.L.; Kimball, J.A.; Wynn, J.R.; Bristow, M.R.

    1991-01-01

    To test the general hypothesis that cardiac innervation may participate in myocardial G protein regulation, we examined the effects of complete intrapericardial surgical denervation or sham operation in dogs. In particulate fractions of dog left ventricular (LV) myocardium harvested 28-33 days after denervation or sham operation, Mr 40,000 and Mr 39,000 pertussis toxin-sensitive substrates (G proteins) were increased by 31% (1.31 +/- 0.084 vs 1.00 +/- 0.058 OD, arbitrary units, p less than 0.01) and 40% (1.40 +/- 0.117 vs. 1.000 +/- 0.084 OD, arbitrary units, p less than 0.02), respectively, as compared with sham-operated controls. The Mr 40,000 pertussis toxin-sensitive band comigrated with a pertussis toxin-sensitive substrate in human erythrocyte membranes known to contain an alpha Gi species. In these same preparations basal, GTP and GppNHp stimulated adenylate cyclase activities were decreased in denervated heart by 20, 26, and 19%, respectively, consistent with increased activity of an inhibitory G protein. In contrast, Gs function was not altered, because cyc(-) membranes reconstituted with membrane extracts and fluoride and beta-receptor-stimulated adenylate cyclase activity were not different between groups. Furthermore, adenylate cyclase catalytic subunit function as assessed with forskolin and manganese stimulation was not different between preparations of control and denervated heart. We conclude that in preparations of surgically denervated dog myocardium Mr 40,000 and Mr 39,000 pertussis toxin-sensitive G proteins are increased by 31 and 40%, respectively, and that functional alterations in adenylate cyclase activity exist, consistent with increased inhibitory G-protein function

  6. Psychosomatic correlations in atrial fibrillations

    Directory of Open Access Journals (Sweden)

    Vladimir Ernstovich Medvedev

    2011-01-01

    Full Text Available Patients with atrial fibrillations (AF and comorbid mental disorders were examined. Two patient groups differing in the structure of psychosomatic ratios were identified. Group 1 comprised patients with AF and signs of reactivity lability that manifested itself as psychopathological reactions to the primary manifestations of AF; Group 2 included those who had developed mental disorders mainly in end-stage cardiovascular disease (predominantly a permanent form of AF in the presence of such events as chronic heart failure (CHF. The results of the study suggest that the patients with AF have frequently anxiety and hypochondriacal disorders, which agrees with the data available in the literature. In addition, end-stage AF is marked by depressive syndromes caused by the severe course of cardiovascular diseases resulting in CHF.

  7. 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...

  8. Red Wine, Resveratrol and Atrial Fibrillation

    Science.gov (United States)

    Garavaglia, Juliano; Marcadenti, Aline

    2017-01-01

    Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as an inhibitor of both intracellular calcium release and pathological signaling cascades in AF, eliminating calcium overload and preserving the cardiomyocyte contractile function. However, there are still no clinical trials at all that prove that resveratrol supplementation leads to improved outcomes. Besides, no observational study supports a beneficial effect of light or moderate alcohol intake and a lower risk of AF. The purpose of this review is to briefly describe possible beneficial effects of red wine and resveratrol in AF, and also present studies conducted in humans regarding chronic red wine consumption, resveratrol, and AF. PMID:29084143

  9. Red Wine, Resveratrol and Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Laura Siga Stephan

    2017-10-01

    Full Text Available Atrial fibrillation (AF is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as an inhibitor of both intracellular calcium release and pathological signaling cascades in AF, eliminating calcium overload and preserving the cardiomyocyte contractile function. However, there are still no clinical trials at all that prove that resveratrol supplementation leads to improved outcomes. Besides, no observational study supports a beneficial effect of light or moderate alcohol intake and a lower risk of AF. The purpose of this review is to briefly describe possible beneficial effects of red wine and resveratrol in AF, and also present studies conducted in humans regarding chronic red wine consumption, resveratrol, and AF.

  10. Red Wine, Resveratrol and Atrial Fibrillation.

    Science.gov (United States)

    Stephan, Laura Siga; Almeida, Eduardo Dytz; Markoski, Melissa Medeiros; Garavaglia, Juliano; Marcadenti, Aline

    2017-10-30

    Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as an inhibitor of both intracellular calcium release and pathological signaling cascades in AF, eliminating calcium overload and preserving the cardiomyocyte contractile function. However, there are still no clinical trials at all that prove that resveratrol supplementation leads to improved outcomes. Besides, no observational study supports a beneficial effect of light or moderate alcohol intake and a lower risk of AF. The purpose of this review is to briefly describe possible beneficial effects of red wine and resveratrol in AF, and also present studies conducted in humans regarding chronic red wine consumption, resveratrol, and AF.

  11. 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.

  12. Circulating Glutamate and Taurine Levels Are Associated with the Generation of Reactive Oxygen Species in Paroxysmal Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Shintaro Takano

    2016-01-01

    Full Text Available Atrial fibrillation (AF is the most common cardiac arrhythmia, but its proarrhythmic mechanism remains to be elucidated. Glutamate (Glu and taurine (Tau are present in the myocardium at substantially higher concentrations than in the plasma, suggesting their active role in myocardium. Here, we tested the hypothesis that the metabolism of Glu and Tau is altered in association with the generation of reactive oxygen species (ROS in patients with AF. Fifty patients with paroxysmal AF and 50 control subjects without a history of AF were consecutively enrolled. Circulating Glu and Tau levels were measured and correlations between Glu/Tau and ROS levels were examined. Glu/Tau content was significantly higher in patients with AF versus controls (Glu: 79.2±23.9 versus 60.5±25.2 nmol/L; Tau: 78.8±19.8 versus 68.5±20.8 nmol/L; mean ± standard deviation (SD, p<0.001 for both. Glu/Tau levels also showed an independent association with AF by multiple logistic regression analysis. Glu and Tau levels both showed significant positive associations with plasma hydroperoxide concentrations. These data suggest a novel pathophysiological role of Glu and Tau in association with ROS production in paroxysmal AF, providing new insights into the elevated amino acid content in cardiac disease.

  13. Review of the emerging role of optical polarimetry in characterization of pathological myocardium.

    Science.gov (United States)

    Ahmad, Iftikhar

    2017-10-01

    Myocardial infarction (MI), a cause of significant morbidity and mortality, is typically followed by microstructural alterations where the necrotic myocardium is steadily replaced with a collagen scar. Engineered remodeling of the fibrotic scar via stem cell regeneration has been shown to improve/restore the myocardium function after MI. Nevertheless, the heterogeneous nature of the scar patch may impair the myocardial electrical integrity, leading to the formation of arrhythmogenesis. Radiofrequency ablation (RFA) offers an effective treatment for focal arrhythmias where local heating generated via electric current at specific spots in the myocardium ablate the arrhythmogenic foci. Characterization of these myocardial pathologies (i.e., infarcted, stem cell regenerated, and RFA-ablated myocardial tissues) is of potential clinical importance. Optical polarimetry, the use of light to map and characterize the polarization signatures of a sample, has emerged as a powerful imaging tool for structural characterization of myocardial tissues, exploiting the underlying highly fibrous tissue nature. This study aims to review the recent progress in optical polarimetry pertaining to the characterization of myocardial pathologies while describing the underlying biological rationales that give rise to the optical imaging contrast in various pathologies of the myocardium. Future possibilities of and challenges to optical polarimetry in cardiac imaging clinics are also discussed. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  14. Pitx2 confers left morphological, molecular, and functional identity to the sinus venosus myocardium

    Czech Academy of Sciences Publication Activity Database

    Ammirabile, G.; Tessari, A.; Pignataro, V.; Szumska, D.; Sardo, F.S.; Beneš Jr., Jiří; Balistreri, M.; Bhattacharya, S.; Sedmera, David; Campione, M.

    2012-01-01

    Roč. 93, č. 2 (2012), s. 291-301 ISSN 0008-6363 R&D Projects: GA ČR(CZ) GA304/08/0615 Institutional research plan: CEZ:AV0Z50110509 Keywords : Pitx2 * sinus venosus myocardium * optical mapping * mouse cardiac development Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 5.940, year: 2012

  15. Preliminary applied study of assessment ischemic/viable myocardium by 99Tcm-HL91

    International Nuclear Information System (INIS)

    Liu Gang; Wu Hua

    2004-01-01

    Objective: To investigate the representation of 99 Tc m -HL91 in the ischemic myocardium, evaluate the diagnosis value of 99 Tc m -HL91 on hypoxic but viable myocardium. Methods: Six patients with cardiac infarction all underwent 99 Tc m -MIBI SPECT and 99 Tc m -HL91 SPECT. Average radioactivity of ischemic area and normal area were respectively obtained by ROI (2 x 2 pixels) on heart minor axis of images, And the radioactivity ratios of target (ischemic area)-to-non target(normal area)were calculated. Results: In image of 99 Tc m -HL91 SPECT, two patients who's radioactivity coloboma of 99 Tc m -MIBI image could be filled with 99 Tc m -HL91, four patients were not caught sight of obvious filling up. Conclusion 99 Tc m -HL91 can be selectively uptaken by ischemic and hypoxic but viable myocardium. it combination of 99 Tc m -MIBI SPECT may be good for accurate diagnosis and differentiation of viable myocardium. (authors)

  16. Sensitization of the Guinea Pig Myocardium through the Mucous Membrane of the Digestive Tract,

    Science.gov (United States)

    Under certain conditions, sessile antibodies can be bound by the guinea - pig myocardium that had been sensitized by direct introduction of the allergen into the stomach. This is confirmed by the positive anaphylactic reaction in the isolated heart of animals treated in this manner, which reaction manifests itself in a modified heart rate when the isolated heart is challenged by the sensitizing allergen.

  17. Neurogenic Stunned Myocardium Associated with Acute Spinal Cord Infarction: A Case Report

    Directory of Open Access Journals (Sweden)

    Gillian A. Beauchamp

    2012-01-01

    Full Text Available Introduction. Neurogenic stunned myocardium (NSM is a reversible cardiomyopathy resulting in transient left ventricular apical ballooning presumed to result from catecholamine surge occurring under physiologic stress. Acute spinal cord ischemia is a rare ischemic vascular lesion. We report a case of neurogenic stunned myocardium occurring in the setting of acute spinal cord infarction. Methods. Singe case report was used. Results. We present the case of a 63-year-old female with a history of prior lacunar stroke, hypertension, chronic back pain, and hypothyroidism who presented with a brief episode of diffuse abdominal and bilateral lower extremity pain which progressed within minutes to bilateral lower extremity flaccid paralysis. MRI of the spinal cord revealed central signal hyperintensity of T2-weighted imaging from conus to T8 region, concerning for acute spinal cord ischemia. Transthoracic echocardiogram was performed to determine if a cardiac embolic phenomenon may have precipitated this ischemic event and showed left ventricular apical hypokinesis and ballooning concerning for NSM. Conclusion. Neurogenic stunned myocardium is a reversible cardiomyopathy which has been described in patients with physiologic stress resulting in ventricular apical ballooning. Our case suggests that it is possible for neurogenic stunned myocardium to occur in the setting of acute spinal cord ischemia.

  18. Metabolic reserve in normal myocardium assessed by positron emission tomography with C-11 palmitate

    International Nuclear Information System (INIS)

    Tamaki, Nagara; Kawamoto, Masahide; Takahashi, Norio; Yonekura, Yoshiharu; Magata, Yasuhiro; Nohara, Ryuji; Kambara, Hirofumi; Kawai, Chuichi; Konishi, Junji

    1991-01-01

    Positron emission tomography (PET) with C-11 palmitate has been used in estimating the myocardial utilization of free fatty acid. To assess the metabolic reserve in normal subjects, a PET study was performed at control and during dobutamine infusion at 2 hour intervals in 5 normal subjects. Following monoexponential curve fitting of the time activity curve of the myocardium, the clearance half time (min) and residual fraction (%) were calculated as indices of β-oxydation of free fatty acid. A significant increase in the heart rate and systolic blood pressure were observed during dobutamine infusion (65±5 vs 100±29 bpm, p<0.05 and 119±12 vs 144±16 mmHg, p<0.01, respectively). The clearance half-time and the residual fraction were significantly decreased (23.4±2.6 vs 15.8±2.3 min and 67.0±2.5 vs 58.6±4.0%, p<0.05, each). When the left ventricular myocardium was divided into 4 segments, these indices were similar at control and uniformly decreased without regional differences during dobutamine infusion. These data suggest that β-oxydation of free fatty acid may be uniformly increased in the left ventricular myocardium in relation to the increase in cardiac work in normal subjects. PET with C-11 palmitate at control and during dobutamine infusion is considered to be promising in assessing metabolic reserve in the myocardium. (author)

  19. Atorvastatin can ameliorate left atrial stunning induced by radiofrequency ablation for atrial fibrillation.

    Science.gov (United States)

    Xie, Ruiqin; Yang, Yingtao; Cui, Wei; Yin, Hongning; Zheng, Hongmei; Zhang, Jidong; You, Ling

    2017-09-01

    The objective of this study was to study the functional changes of the left atrium after radiofrequency ablation treatment for atrial fibrillation and the therapeutic effect of atorvastatin. Fifty-eight patients undergoing radiofrequency ablation for atrial fibrillation were randomly divided into non-atorvastatin group and atorvastatin group. Patients in the atorvastatin group were treated with atorvastatin 20 mg p.o. per night in addition to the conventional treatment of atrial fibrillation; patients in the non-atorvastatin group received conventional treatment of atrial fibrillation only. Echocardiography was performed before radiofrequency ablation operation and 1 week, 2 weeks, 3 weeks, and 4 weeks after operation. Two-dimensional ultrasound speckle tracking imaging system was used to measure the structural indexes of the left atrium. Results indicated that there was no significant change for indexes representing the structural status of the left atrium within a month after radiofrequency ablation (P > 0.05); however, there were significant changes for indexes representing the functional status of the left atrium. There were also significant changes in indexes reflecting left atrial strain status: the S and SRs of atorvastatin group were higher than those of non-atorvastatin group (P atorvastatin could improve left atrial function and shorten the duration of atrial stunning after radiofrequency ablation of atrial fibrillation.

  20. 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

  1. Incisional left atrial isolation for ablation of atrial fibrillation in mitral valve surgery.

    Science.gov (United States)

    Graffigna, Angelo; Branzoli, Stefano; Sinelli, Stefano; Vigano, Mario

    2009-01-01

    The renewed interest in surgical techniques for atrial fibrillation (AF) limited to the left atrium has risen the importance of the original technique of left atrial isolation by means of surgical incision. Transmurality of lesions and cost containment are strong elements to be appreciated in this technique.

  2. Radiolabeled Rhein as Small-Molecule Necrosis Avid Agents for Imaging of Necrotic Myocardium.

    Science.gov (United States)

    Luo, Qi; Jin, Qiaomei; Su, Chang; Zhang, Dongjian; Jiang, Cuihua; Fish, Anne Folta; Feng, Yuanbo; Ni, Yicheng; Zhang, Jian; Yin, Zhiqi

    2017-01-17

    A rapid and accurate identification of necrotic myocardium is of great importance for diagnosis, risk stratification, clinical decision-making, and prognosis evaluation of myocardial infarction. Here, we explored technetium-99m labeled rhein derivatives for rapid imaging of the necrotic myocardium. Three hydrazinonicotinic acid-linker-rhein (HYNIC-linker-rhein) derivatives were synthesized, and then, these synthetic compounds were labeled with technetium-99m using ethylenediaminediacetic acid (EDDA) and tricine as coligands [ 99m Tc(EDDA)-HYNIC-linker-rhein]. The necrosis avidity of the three 99m Tc-labeled rhein derivatives was tested in a mouse model of ethanol-induced muscular necrosis by gamma counting, histochemical staining, and autoradiography. A lead tracer for visualization of necrotic myocardium was assessed by single photon emission computed tomography/computed tomography (SPECT/CT) imaging in a rat model with reperfused myocardial infarction. The necrosis avidity mechanism of the tracer was explored by DNA binding studies in vitro and blocking experiments in vivo. Results showed that the uptake in necrotic muscles of the three 99m Tc-compounds was higher than that in viable muscles (P EDDA)-HYNIC-ethylenediamine-rhein [ 99m Tc(EDDA)-HYNIC-2C-rhein] displayed the best distribution profiles for imaging. The necrotic myocardium lesions were clearly visualized by SPECT/CT using 99m Tc(EDDA)-HYNIC-2C-rhein at 1 h after injection. The necrotic-to-viable myocardium and necrotic myocardium-to-blood uptake ratios of 99m Tc(EDDA)-HYNIC-2C-rhein were 4.79 and 3.02 at 1 h after injection. DNA binding studies suggested HYNIC-linker-rhein bound to DNA through intercalation. The uptake of 99m Tc(EDDA)-HYNIC-2C-rhein in necrotic muscle was significantly blocked by excessive unlabeled rhein, with 77.61% decline at 1 h after coinjection. These findings suggested 99m Tc(EDDA)-HYNIC-2C-rhein emerged as a "hot spot" imaging probe that has a potential for rapid imaging of

  3. 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

    contains patient level-data from randomized trials of stroke prevention in atrial fibrillation. We used Cox regression models with age as a continuous variable that controlled for sex, year of randomization, and history of cerebrovascular disease, diabetes, hypertension, and congestive heart failure......BACKGROUND AND PURPOSE: Stroke risk increases with age in patients who have nonvalvular atrial fibrillation. It is uncertain whether the efficacy of stroke prevention therapies in atrial fibrillation changes as patients age. The objective of this study was to determine the effect of age...... 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...

  4. Comparative study between MRI and echocardiography in noncompaction of ventricular myocardium

    International Nuclear Information System (INIS)

    Sun Ziyan; Xia Liming; Wang Chengyuan; Rao Jingjing; Shenyu Weihui

    2007-01-01

    Objective: To investigate the MRI and echocardiography manifestations of noncompaction of ventricular myocardium(NVM) and assess the role of MR1 in the diagnosis of NVM by comparing it with echocardiography. Methods: Fourteen cases of NVM diagnosed by echocardiography were examined with MRI, including scanning of black-blood sequences, double inversion recovery fast spin echo (DIBFSE) and triple inversion recovery fast spin echo (TIRFSE), and white blood sequence: fast imaging employ steady state acquisition (FIESTA). Scanning plane includes short axis view, four-chamber view and long axis view. Results: Both MRI and echocardiography displayed involvement of left ventricles in thirteen cases and involvement of double ventricles in one case. Apexes of heart and the intermedius are commonly affected. MRI showed 54 segments and echocardiography showed 53 segments affected, and there is no significant difference between the capability of MRI and echocardiography (P=1,000). The affected myocardium consisted of two layers: subendocardial noncompacted myocardium and epicardial compacted myocardium, and the ratio measurement of N/C by MRI was 3.37±0.89 and it was 3.19±0.82 by echocardiography. Noncompacted myocardium was characterized by prominent and excessive myocardial trabeculations and deep intratrabecular recesses, in which the blood flow was communicated with the ventricle. One case was complicated with ventricular aneurysm, and coronary arteriography was performed with unremarkable findings. One case underwent heart transplantation because of progressive heart failure, Gross findings demonstrated prominent muscular' trabeculations with deep intratrabecular recesses, which coincided well with MRI findings. Conclusion: The MRI manifestation of NVM is characteristic, and MRI with multiple series and planes is helpful in the diagnose of NVM. Compared with echocardiography, MRI could display the pathological cardiac muscle more clearly, because of its high soft

  5. Subacute ghrelin administration inhibits apoptosis and improves ultrastructural abnormalities in remote myocardium post-myocardial infarction.

    Science.gov (United States)

    Eid, Refaat A; Zaki, Mohamed Samir Ahmed; Al-Shraim, Mubarak; Eleawa, Samy M; El-Kott, Attalla Farag; Al-Hashem, Fahaid H; Eldeen, Muhammad Alaa; Ibrahim, Hoja; Aldera, Hussain; Alkhateeb, Mahmoud A

    2018-05-01

    This study investigated the effect of ghrelin on cardiomyocytes function, apoptosis and ultra-structural alterations of remote myocardium of the left ventricle (LV) of rats, 21 days post myocardial infarction (MI). Rats were divided into 4 groups as a control, a sham-operated rats, a sham-operated+ghrelin, an MI + vehicle and an MI + ghrelin-treated rats. MI was induced by LAD ligation and then rats were recievd a concomitant doe of either normal saline as a vehicle or treated with ghrelin (100 μg/kg S.C., 2x/day) for 21 consecutive days. Ghrelin enhanced myocardial contractility in control rats and reversed the decreases in myocardial contractility and the increases in the serum levels of CK-MB and LDH in MI-induced rats. Additionally, it inhibited the increases in levels of Bax and cleaved caspase 3 and increased those for Bcl-2 in the remote myocardium of rat's LV, post-MI. At ultra-structural level, while ghrelin has no adverse effects on LV myocardium obtained from control or sham-treated rats, ghrelin post-administration to MI-induced rats reduced vascular formation, restored normal microfilaments appearance and organization, preserved mitochondria structure, and prevented mitochondrial swelling, collagen deposition and number of ghost bodies in the remote areas of their LV. Concomitantly, in remote myocardium of MI-induced rats, ghrelin enhanced endoplasmic reticulum intracellular organelles count, decreased number of atrophied nuclei and phagocytes, diminished the irregularity in the nuclear membranes and inhibited chromatin condensation. In conclusion, in addition to the physiological, biochemical and molecular evidence provided, this is the first study that confirms the anti-apoptotic effect of ghrelin in the remote myocardium of the LV during late MI at the level of ultra-structural changes. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  6. Applying non-linear dynamics to atrial appendage flow data to understand and characterize atrial arrhythmia

    International Nuclear Information System (INIS)

    Chandra, S.; Grimm, R.A.; Katz, R.; Thomas, J.D.

    1996-01-01

    The aim of this study was to better understand and characterize left atrial appendage flow in atrial fibrillation. Atrial fibrillation and flutter are the most common cardiac arrhythmias affecting 15% of the older population. The pulsed Doppler velocity profile data was recorded from the left atrial appendage of patients using transesophageal echocardiography. The data was analyzed using Fourier analysis and nonlinear dynamical tools. Fourier analysis showed that appendage mechanical frequency (f f ) for patients in sinus rhythm was always lower (around1 Hz) than that in atrial fibrillation (5-8 Hz). Among patients with atrial fibrillation spectral power below f f was significantly different suggesting variability within this group of patients. Results that suggested the presence of nonlinear dynamics were: a) the existence of two arbitrary peak frequencies f 1 , f 2 , and other peak frequencies as linear combinations thereof (mf 1 ±nf 2 ), and b) the similarity between the spectrum of patient data and that obtained using the Lorenz equation. Nonlinear analysis tools, including Phase plots and differential radial plots, were also generated from the velocity data using a delay of 10. In the phase plots, some patients displayed a torus-like structure, while others had a more random-like pattern. In the differential radial plots, the first set of patients (with torus-like phase plots) showed fewer values crossing an arbitrary threshold of 10 than did the second set (8 vs. 27 in one typical example). The outcome of cardioversion was different for these two set of patients. Fourier analysis helped to: differentiate between sinus rhythm and atrial fibrillation, understand the characteristics of the wide range of atrial fibrillation patients, and provide hints that atrial fibrillation could be a nonlinear process. Nonlinear dynamical tools helped to further characterize and sub-classify atrial fibrillation

  7. Refractoriness in human atria

    DEFF Research Database (Denmark)

    Skibsbye, Lasse; Jespersen, Thomas; Christ, Torsten

    2016-01-01

    BACKGROUND: Refractoriness of cardiac cells limits maximum frequency of electrical activity and protects the heart from tonic contractions. Short refractory periods support major arrhythmogenic substrates and augmentation of refractoriness is therefore seen as a main mechanism of antiarrhythmic...... drugs. Cardiomyocyte excitability depends on availability of sodium channels, which involves both time- and voltage-dependent recovery from inactivation. This study therefore aims to characterise how sodium channel inactivation affects refractoriness in human atria. 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...

  8. Atrial tachyarrhythmia in adult congenital heart disease

    Science.gov (United States)

    Karbassi, Arsha; Nair, Krishnakumar; Harris, Louise; Wald, Rachel M; Roche, S Lucy

    2017-01-01

    The adult congenital heart disease (ACHD) population continues to grow and most cardiologists, emergency room physicians and family doctors will intermittently come into contact with these patients. Oftentimes this may be in the setting of a presentation with atrial tachyarrhythmia; one of the commonest late complications of ACHD and problem with potentially serious implications. Providing appropriate initial care and ongoing management of atrial tachyarrhythmia in ACHD patients requires a degree of specialist knowledge and an awareness of certain key issues. In ACHD, atrial tachyarrhythmia is usually related to the abnormal anatomy of the underlying heart defect and often occurs as a result of surgical scar or a consequence of residual hemodynamic or electrical disturbances. Arrhythmias significantly increase mortality and morbidity in ACHD and are the most frequent reason for ACHD hospitalization. Intra-atrial reentrant tachycardia and atrial fibrillation are the most prevalent type of arrhythmia in this patient group. In hemodynamically unstable patients, urgent cardioversion is required. Acute management of the stable patient includes anticoagulation, rate control, and electrical or pharmacological cardioversion. In ACHD, rhythm control is the preferred management strategy and can often be achieved. However, in the long-term, medication side-effects can prove problematic. Electrophysiology studies and catheter ablation are important treatments modalities and in certain cases, surgical or percutaneous treatment of the underlying cardiac defect has a role. ACHD patients, especially those with complex CHD, are at increased risk of thromboembolic events and anticoagulation is usually required. Female ACHD patients of child bearing age may wish to pursue pregnancies. The risk of atrial arrhythmias is increased during pregnancy and management of atrial tachyarrhythmia during pregnancy needs specific consideration. PMID:28706585

  9. Spectral of electrocardiographic RR intervals to indicate atrial fibrillation

    Science.gov (United States)

    Nuryani, Nuryani; Satrio Nugroho, Anto

    2017-11-01

    Atrial fibrillation is a serious heart diseases, which is associated on the risk of death, and thus an early detection of atrial fibrillation is necessary. We have investigated spectral pattern of electrocardiogram in relation to atrial fibrillation. The utilized feature of electrocardiogram is RR interval. RR interval is the time interval between a two-consecutive R peaks. A series of RR intervals in a time segment is converted to a signal with a frequency domain. The frequency components are investigated to find the components which significantly associate to atrial fibrillation. A segment is defined as atrial fibrillation or normal segments by considering a defined number of atrial fibrillation RR in the segment. Using clinical data of 23 patients with atrial fibrillation, we find that the frequency components could be used to indicate atrial fibrillation.

  10. 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....

  11. Treatment Guidelines of Atrial Fibrillation (AFib or AF)

    Science.gov (United States)

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Treatment Guidelines of Atrial Fibrillation (AFib or AF) Updated:Jun 28,2017 What are the treatment guidelines for atrial fibrillation? Medical guidelines are written by ...

  12. 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); Patrial CFE area was reduced by LA ablation, from 25.9±14.1 to 12.9±11.8 cm(2) (Patrial 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.

  13. Endothelial progenitor cells regenerate infracted myocardium with neovascularisation development.

    Science.gov (United States)

    Abd El Aziz, M T; Abd El Nabi, E A; Abd El Hamid, M; Sabry, D; Atta, H M; Rahed, L A; Shamaa, A; Mahfouz, S; Taha, F M; Elrefaay, S; Gharib, D M; Elsetohy, Khaled A

    2015-03-01

    We achieved possibility of isolation, characterization human umbilical cord blood endothelial progenitor cells (EPCs), examination potency of EPCs to form new blood vessels and differentiation into cardiomyoctes in canines with acute myocardial infarction (AMI). EPCs were separated and cultured from umbilical cord blood. Their phenotypes were confirmed by uptake of double stains dioctadecyl tetramethylindocarbocyanine-labeled acetylated LDL and FITC-labeled Ulex europaeus agglutinin 1 (DILDL-UEA-1). EPCs of cord blood were counted. Human VEGFR-2 and eNOS from the cultured EPCs were assessed by qPCR. Human EPCs was transplanted intramyocardially in canines with AMI. ECG and cardiac enzymes (CK-MB and Troponin I) were measured to assess severity of cellular damage. Histopathology was done to assess neovascularisation. Immunostaining was done to detect EPCs transdifferentiation into cardiomyocytes in peri-infarct cardiac tissue. qPCR for human genes (hVEGFR-2, and eNOS) was done to assess homing and angiogenic function of transplanted EPCs. Cultured human cord blood exhibited an increased number of EPCs and significant high expression of hVEGFR-2 and eNOS genes in the culture cells. Histopathology showed increased neovascularization and immunostaining showed presence of EPCs newly differentiated into cardiomyocyte-like cells. Our findings suggested that hEPCs can mediate angiogenesis and differentiate into cardiomyoctes in canines with AMI.

  14. Endothelial progenitor cells regenerate infracted myocardium with neovascularisation development

    Directory of Open Access Journals (Sweden)

    M.T. Abd El Aziz

    2015-03-01

    Full Text Available We achieved possibility of isolation, characterization human umbilical cord blood endothelial progenitor cells (EPCs, examination potency of EPCs to form new blood vessels and differentiation into cardiomyoctes in canines with acute myocardial infarction (AMI. EPCs were separated and cultured from umbilical cord blood. Their phenotypes were confirmed by uptake of double stains dioctadecyl tetramethylindocarbocyanine-labeled acetylated LDL and FITC-labeled Ulex europaeus agglutinin 1 (DILDL-UEA-1. EPCs of cord blood were counted. Human VEGFR-2 and eNOS from the cultured EPCs were assessed by qPCR. Human EPCs was transplanted intramyocardially in canines with AMI. ECG and cardiac enzymes (CK-MB and Troponin I were measured to assess severity of cellular damage. Histopathology was done to assess neovascularisation. Immunostaining was done to detect EPCs transdifferentiation into cardiomyocytes in peri-infarct cardiac tissue. qPCR for human genes (hVEGFR-2, and eNOS was done to assess homing and angiogenic function of transplanted EPCs. Cultured human cord blood exhibited an increased number of EPCs and significant high expression of hVEGFR-2 and eNOS genes in the culture cells. Histopathology showed increased neovascularization and immunostaining showed presence of EPCs newly differentiated into cardiomyocyte-like cells. Our findings suggested that hEPCs can mediate angiogenesis and differentiate into cardiomyoctes in canines with AMI.

  15. 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).......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)....

  16. 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.

  17. Electrical remodeling and atrial dilation during atrial tachycardia are influenced by ventricular rate : Role of developing tachycardiomyopathy

    NARCIS (Netherlands)

    Schoonderwoerd, BA; Van Gelder, IC; Van Veldhuisen, DJ; Tieleman, RG; Grandjean, JG; Bel, KJ; Allessie, MA; Crijns, HJGM

    2001-01-01

    Atrial Remodeling in Tachycardiomyopathy. Introduction: Atrial fibrillation (AF) and congestive heart failure (CHF) are two clinical entities that often coincide. Our aim was to establish the influence of concomitant high ventricular rate and consequent development of CHF on electrical remodeling

  18. Ventricular myocarditis coincides with atrial myocarditis in patients

    NARCIS (Netherlands)

    Begieneman, Mark P. V.; Emmens, Reindert W.; Rijvers, Liza; Kubat, Bela; Paulus, Walter J.; Vonk, Alexander B. A.; Rozendaal, Lawrence; Biesbroek, P. Stefan; Wouters, Diana; Zeerleder, Sacha; van Ham, Marieke; Heymans, Stephane; van Rossum, Albert C.; Niessen, Hans W. M.; Krijnen, Paul A. J.

    2016-01-01

    Atrial fibrillation (AF) is a common complication in myocarditis. Atrial inflammation has been suggested to play an important role in the pathophysiology of AF. However, little is known about the occurrence of atrial inflammation in myocarditis patients. Here, we analyzed inflammatory cell numbers

  19. 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.

  20. A Therapeutic Challenge: Management of Atrial Thrombus

    Directory of Open Access Journals (Sweden)

    Serkan Burc Deser

    2016-09-01

    Full Text Available Introduction: Primary cause of atrial thrombi include atrial fibrillation, foreign bodies inside the atrium such as catheters and pacemaker leads, emboli of deep venous thrombus and primary or metastatic tumors of the heart. We review the clinical features, epidemiology, diagnosis and treatment of nine intriguing cases with atrial thrombus. Methods: This is a retrospective study of nine patients (seven female (78%, two male (33% who were diagnosed with atrial thrombi (average age of 50 ± 12 years and were treated at the Ondokuz Mayis University, Department of Cardiovascular Surgery from February 2014 to January 2015. Among them, six patients had atrial fibrillation (one male, five female, seven patients were suffering from dispne and orthopnoea, five patients were suffering from leg swelling, seven patients had a history of hypertension and three patients had a history of mitral valve replacement surgery. Results: All patients underwent surgery except one. Four patients recovered uneventfully and discharged with oral anticoagulation (warfarin therapy (adjusted to maintain an international normalized ratio of INR between two and three times. Five of nine patients (55% died after surgery. Conclusion: The response to the thrombolytic therapy is poor, mostly ineffective and unsafe so it is often recommended as a bridge to surgery. In patients diagnosed with mechanical mitral valve thrombosis, medical therapy has the possibility of end organ emboli and also fail to resolve the organised thrombus on the stuck valve. On the other hand surgery does not always give satisfactory results. J Clin Exp Invest 2016; 7(4: 278-282

  1. Fractal analysis of phasic laser images of the myocardium for the purpose of diagnostics of acute coronary insufficiency

    Science.gov (United States)

    Wanchuliak, O. Y.; Bachinskyi, V. T.

    2011-09-01

    In this work on the base of Mueller-matrix description of optical anisotropy, the possibility of monitoring of time changes of myocardium tissue birefringence, has been considered. The optical model of polycrystalline networks of myocardium is suggested. The results of investigating the interrelation between the values correlation (correlation area, asymmetry coefficient and autocorrelation function excess) and fractal (dispersion of logarithmic dependencies of power spectra) parameters are presented. They characterize the distributions of Mueller matrix elements in the points of laser images of myocardium histological sections. The criteria of differentiation of death coming reasons are determined.

  2. Atrial antitachycardia pacing and atrial remodeling: A substudy of the international, randomized MINERVA trial.

    Science.gov (United States)

    Boriani, Giuseppe; Tukkie, Raymond; Biffi, Mauro; Mont, Lluis; Ricci, Renato; Pürerfellner, Helmut; Botto, Giovanni Luca; Manolis, Antonis S; Landolina, Maurizio; Gulizia, Michele; Hudnall, J Harrison; Mangoni, Lorenza; Grammatico, Andrea; Padeletti, Luigi

    2017-10-01

    Atrial tachycardia (AT) and atrial fibrillation (AF) are common in pacemaker patients and are associated with bad prognoses. The purpose of this study was to evaluate atrial antitachycardia pacing impact on AT/AF-induced atrial remodeling, measured by early recurrence of AT/AF (ERAF) and by change in left atrial diameter (LAD), and to evaluate the impact of AT/AF duration on ERAF incidence. Pacemaker patients were randomized to dual-chamber pacing (Control DDDR: 385 patients), managed ventricular pacing (MVP: 398 patients), or atrial antitachycardia pacing plus MVP (DDDRP+MVP: 383 patients). LAD change, estimated by echocardiography, was considered significant if the relative difference between baseline and 24-month measurements was >10%. At median follow-up of 34 months, ERAF incidence was significantly lower in the DDDRP+MVP arm for all AT/AF durations, in particular, ERAF followed AT/AF longer than 3 hours in 53% cases in Control DDDR, in 51% cases in MVP, and in 39% cases in DDDRP+MVP (P MVP, and 70% in DDDRP+MVP (P MVP, DDDRP+MVP reduces ERAF and favors LAD reduction, suggesting that atrial antitachycardia pacing may reverse electrical and mechanical remodeling. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  3. Left atrial size and function as predictors of new-onset of atrial fibrillation in patients with asymptomatic aortic stenosis

    DEFF Research Database (Denmark)

    Bang, Casper Niels Furbo; Dalsgaard, Morten; Greve, Anders

    2013-01-01

    Left atrial (LA) size and function change with chronically increased left ventricular (LV) filling pressures. It remains unclear whether these variations in LA parameters can predict new-onset atrial fibrillation (AF) in asymptomatic patients with aortic stenosis (AS).......Left atrial (LA) size and function change with chronically increased left ventricular (LV) filling pressures. It remains unclear whether these variations in LA parameters can predict new-onset atrial fibrillation (AF) in asymptomatic patients with aortic stenosis (AS)....

  4. The Histological Effects of L-arginine on Ventricular Myocardium in Iron Treated Male Rats

    Directory of Open Access Journals (Sweden)

    M Sofiabadi

    2012-05-01

    Full Text Available

    Background and Objectives: Iron overload is detrimental for the body and can create damage to different body tissues, such as myocardium by producing oxidative stress. Therefore, the antioxidant factors can neutralize iron induced damages. According to available reports, L-arginine as a precursor nitric oxide production has antioxidant effects. This study was carried out to evaluate the histological effects of iron overload on ventricular muscle and preventive role of L-arginine in male rats.
    Methods: In this experiment, 40 male rats with weight range of 300-250g were divided at random into five equal groups including:1- Control, 2- Iron (10mg/kg, ip, 3- Iron(10mg/kg, ip+L-arginine (1mg/ml, po, 4- Iron (50mg/kg, ip and 5- Iron (50mg/kg,ip+L-arginine(1mg/ml,po. After treatment (6 weeks, the animals were anesthetized and the samples of left apical ventricular myocardium were taken out and morphological studies were done following fixation with 10% formalin and H&E staining. Microscopic parameters under study were cell swelling, vessel dilatation and hypercongestion, cell necrosis and tissue deformity. The type and severity of damage to the tissue were also noted. Data were analyzed using chi-square statistical procedure, and Pvalue≤0.05 were considered to be significant. 
    Results: The data showed moderate changes in the ventricular myocardium of group 2 that was significant in comparison to the control group (P<0.05. The ventricular myocardium of group 3 showed low changes and wasn't significant in comparison to control group (P=0.84. The ventricular myocardium of the group 4 showed severe changes in comparison to the control group (P<0.01. The low change showed in the ventricular myocardium of group 5 that wasn't significant in comparison to the control group.

    Conclusion: This study showed

  5. 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

  6. 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.

  7. 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

  8. Role of atrial endothelial cells in the development of atrial fibrosis and fibrillation in response to pressure overload.

    Science.gov (United States)

    Kume, Osamu; Teshima, Yasushi; Abe, Ichitaro; Ikebe, Yuki; Oniki, Takahiro; Kondo, Hidekazu; Saito, Shotaro; Fukui, Akira; Yufu, Kunio; Miura, Masahiro; Shimada, Tatsuo; Takahashi, Naohiko

    Monocyte chemoattractant protein-1 (MCP-1)-mediated inflammatory mechanisms have been shown to play a crucial role in atrial fibrosis induced by pressure overload. In the present study, we investigated whether left atrial endothelial cells would quickly respond structurally and functionally to pressure overload to trigger atrial fibrosis and fibrillation. Six-week-old male Sprague-Dawley rats underwent suprarenal abdominal aortic constriction (AAC) or a sham operation. By day 3 after surgery, macrophages were observed to infiltrate into the endocardium. The expression of MCP-1 and E-selectin in atrial endothelium and the expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and ED1 in left atrial tissue were enhanced. Atrial endothelial cells were irregularly hypertrophied with the disarrangement of lines of cells by scanning electron microscopy. Various-sized gap formations appeared along the border in atrial endothelial cells, and several macrophages were located just in the endothelial gap. Along with the development of heterogeneous interstitial fibrosis, interatrial conduction time was prolonged and the inducibility of atrial fibrillation by programmed extrastimuli was increased in the AAC rats compared to the sham-operated rats. Atrial endothelium responds rapidly to pressure overload by expressing adhesion molecules and MCP-1, which induce macrophage infiltration into the atrial tissues. These processes could be an initial step in the development of atrial remodeling for atrial fibrillation. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. 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...... electroanatomic LA mapping, and all pulmonary vein ostia were marked under the help of pulmonary veins angiography on the 3D map. Radiofrequency (RF) energy was delivered to create continuous linear lesions encircling the pulmonary veins, it was delivered with a target temperature of 43¿, a maximal power limit...

  10. 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...... alcohol than people with low risk. METHODS: We used data for a total of 88,782 men and women from the Copenhagen City Heart Study 1991-1994 and 2001-2003 and the Copenhagen General Population Study 2003-2010. Information on incident cases of atrial fibrillation was obtained from a validated nationwide...... 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...

  11. 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...... was achieved in 40.7% of patients (43.7% in paroxysmal AF; 30.2% in persistent AF; 36.7% in long-lasting persistent AF). A second ablation was required in 18% of the cases and 43.4% were under antiarrhythmic treatment. Thirty-three patients (2.5%) suffered an adverse event, 272 (21%) experienced a left atrial...... 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...

  12. 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...

  13. 14(R,S)-[18F]Fluoro-6-thia-heptadecanoic acid as a tracer of free fatty acid uptake and oxidation in myocardium and skeletal muscle

    International Nuclear Information System (INIS)

    Takala, Teemu O.; Nuutila, Pirjo; Pulkki, Kari; Oikonen, Vesa; Groenroos, Tove; Bergman, Joergen; Forsback, Sarita; Knuuti, Juhani; Savunen, Timo; Vaehaesilta, Tommi; Luotolahti, Matti; Kallajoki, Markku

    2002-01-01

    14(R,S)-[ 18 F]Fluoro-6-thia-heptadecanoic acid ([ 18 F]FTHA) is a long-chain fatty acid substrate for fatty acid metabolism. [ 18 F]FTHA has been used to study fatty acid metabolism in human heart and skeletal muscle. It has been suggested that the rate of radioactivity accumulation in the myocardium reflects the beta-oxidation rate of free fatty acids (FFAs). However, the net accumulation of FFAs in tissue always represents the sum of FFA oxidation and incorporation into triglycerides. The fraction of [ 18 F]FTHA entering directly into mitochondria for oxidation has not been previously measured. Eight anaesthetized pigs were studied with [ 18 F]FTHA and positron emission tomography (PET). Immediately after each PET experiment, tissue samples from myocardium and skeletal muscle were taken for the isolation of mitochondria and measurements of radioactivity accumulation, and for intracellular [ 18 F]FTHA metabolite analysis. Fractional [ 18 F]FTHA uptake rates were calculated both by graphical analysis of PET data and by measuring 18 F in the tissue samples. Fractional [ 18 F]FTHA uptake rates based on the analysis of tissue samples were 0.56±0.17 ml g -1 min -1 and 0.037±0.007 ml g -1 min -1 for myocardium and skeletal muscle (mean ± SD), respectively. The myocardial results obtained from the PET data (0.50±0.11 ml g -1 min -1 ) were similar to the values obtained from the tissue samples (r=0.94, P=0.002). We also found that 89%±23% (mean±SD, n=7) of the 18 F entered mitochondria in myocardium, as compared with only 36%±15% (mean±SD, n=7) in skeletal muscle. Intracellular [ 18 F]FTHA metabolite analysis showed that a major part of [ 18 F]FTHA is metabolized in the mitochondria in the heart. Our data suggest that 89% of [ 18 F]FTHA taken up by the heart enters mitochondria. This supports the hypothesis that [ 18 F]FTHA traces FFA beta-oxidation in the heart. In contrast to this, only 36% of [ 18 F]FTHA accumulated in skeletal muscle appears to directly enter

  14. Exercise-based cardiac rehabilitation for adults with atrial fibrillation

    DEFF Research Database (Denmark)

    Risom, Signe Stelling; Zwisler, Ann-Dorthe; Johansen, Pernille Palm

    2017-01-01

    BACKGROUND: Exercise-based cardiac rehabilitation may benefit adults with atrial fibrillation or those who had been treated for atrial fibrillation. Atrial fibrillation is caused by multiple micro re-entry circuits within the atrial tissue, which result in chaotic rapid activity in the atria....... OBJECTIVES: To assess the benefits and harms of exercise-based rehabilitation programmes, alone or with another intervention, compared with no-exercise training controls in adults who currently have AF, or have been treated for AF. SEARCH METHODS: We searched the following electronic databases; CENTRAL...... the benefits and harms of exercise-based cardiac rehabilitation for adults with atrial fibrillation on patient-relevant outcomes....

  15. Age-dependent changes in expression of alpha1-adrenergic receptors in rat myocardium

    International Nuclear Information System (INIS)

    Schaffer, W.; Williams, R.S.

    1986-01-01

    The expression of alpha 1 -adrenergic receptors within ventricular myocardium of rats ranging in age from 21 days of fetal life to 24 months after birth was measured from [ 125 I] 2-(β hydroxy phenyl) ethylaminomethyl tetralone binding isotherms. No difference was observed in binding affinity between any of the age groups studied. The number of alpha 1 -adrenergic receptors was found to be 60-120% higher in membranes from fetal or immature rats up to 25 days of age when compared with adult animals. The increased expression of alpha 1 -adrenergic receptors in the developing heart relative to that observed in adult heart is consistent with the hypothesis that alpha 1 -adrenergic receptor stimulation may modulate protein synthesis and growth in mammalian myocardium

  16. Kronisk iskaemisk hjerteinsufficiens. Revaskularisering bedrer overlevelsen blandt patienter med hibernating myocardium

    DEFF Research Database (Denmark)

    Holdgaard, Paw Chr; Nielsen, Søren Steen; Wiggers, Henrik

    2007-01-01

    imaging was performed with 99mTc-sestamibi and glucose metabolism was visualized with 18F-fluorodeoxyglucose (18F-FDG) gamma camera PET. Medical records and death certificate were reviewed retrospectively. RESULTS: 50 patients were included. We found an increased survival among patients with HIB who......INTRODUCTION: Patients with ischemic heart failure and reversible dysfunctional myocardium (Hibernating myocardium, HIB) can benefit from revascularization. These patients can be selected with nuclear methods. The purpose of this study was to describe the results of the imaging procedures...... in patients tested for HIB and relate the results to the choice of treatment and cause of death. MATERIALS AND METHODS: During a 2-year period 51 patients were referred to determine the amount of HIB. This can be determined with blood flow and metabolic imaging of the heart. Resting-myocardial perfusion...

  17. Role of the P-wave high frequency energy and duration as noninvasive cardiovascular predictors of paroxysmal atrial fibrillation.

    Science.gov (United States)

    Alcaraz, Raúl; Martínez, Arturo; Rieta, José J

    2015-04-01

    A normal cardiac activation starts in the sinoatrial node and then spreads throughout the atrial myocardium, thus defining the P-wave of the electrocardiogram. However, when the onset of paroxysmal atrial fibrillation (PAF) approximates, a highly disturbed electrical activity occurs within the atria, thus provoking fragmented and eventually longer P-waves. Although this altered atrial conduction has been successfully quantified just before PAF onset from the signal-averaged P-wave spectral analysis, its evolution during the hours preceding the arrhythmia has not been assessed yet. This work focuses on quantifying the P-wave spectral content variability over the 2h preceding PAF onset with the aim of anticipating as much as possible the arrhythmic episode envision. For that purpose, the time course of several metrics estimating absolute energy and ratios of high- to low-frequency power in different bands between 20 and 200Hz has been computed from the P-wave autoregressive spectral estimation. All the analyzed metrics showed an increasing variability trend as PAF onset approximated, providing the P-wave high-frequency energy (between 80 and 150Hz) a diagnostic accuracy around 80% to discern between healthy subjects, patients far from PAF and patients less than 1h close to a PAF episode. This discriminant power was similar to that provided by the most classical time-domain approach, i.e., the P-wave duration. Furthermore, the linear combination of both metrics improved the diagnostic accuracy up to 88.07%, thus constituting a reliable noninvasive harbinger of PAF onset with a reasonable anticipation. The information provided by this methodology could be very useful in clinical practice either to optimize the antiarrhythmic treatment in patients at high-risk of PAF onset and to limit drug administration in low risk patients. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  18. Patients with atrial fibrillation and permanent pacemaker

    DEFF Research Database (Denmark)

    Dalgaard, Frederik; Ruwald, Martin H; Lindhardt, Tommi Bo

    2018-01-01

    BACKGROUND: The management of patients with non-valvular atrial fibrillation (NVAF) with rate-lowering or anti-arrhythmic drugs has markedly changed over the last decade, but it is unknown how these changes have affected patients with NVAF with a permanent pacemaker (PPM). METHODS: Through Danish......,261. Thus, the proportional amount of NVAF patients with a PPM decreased from 1.3% to 1.1% (p = 0.015). Overall 45.9% had atrial fibrillation (AF) duration less than one year and the proportion declined from 55.5% to 42.4% (p

  19. Atrial fibrillation and risk of stroke

    DEFF Research Database (Denmark)

    Christiansen, Christine Benn; Gerds, Thomas A.; Olesen, Jonas Bjerring

    2016-01-01

    AIM: Although the relation between stroke risk factors and stroke in patients with atrial fibrillation (AF) has been extensively examined, only few studies have explored the association of AF and the risk of ischaemic stroke/systemic thromboembolism/transient ischaemic attack (stroke.......5-10.6), and 15.4% (14.5-16.4), respectively. CONCLUSIONS: Stroke/TE/TIA risk was particularly increased when prior stroke/TE/TIA was present. Atrial fibrillation is associated with an increase in risk of stroke/TE/TIA in the absence of other risk factors but only a moderate increase in risk when other risk...

  20. Integrating new approaches to atrial fibrillation management

    DEFF Research Database (Denmark)

    Kotecha, Dipak; Breithardt, Günter; Camm, A John

    2018-01-01

    There are major challenges ahead for clinicians treating patients with atrial fibrillation (AF). The population with AF is expected to expand considerably and yet, apart from anticoagulation, therapies used in AF have not been shown to consistently impact on mortality or reduce adverse...... of the Atrial Fibrillation Network (AFNET) and the European Heart Rhythm Association (EHRA), held at the European Society of Cardiology Heart House in Sophia Antipolis, France, 17-19 January 2017. Sixty-two global specialists in AF and 13 industry partners met to develop innovative solutions based on new...

  1. Initiation of anticoagulation in atrial fibrillation

    DEFF Research Database (Denmark)

    Gundlund, A.; Staerk, L.; Fosbøl, E. L.

    2017-01-01

    Background: The use of non-vitamin K antagonist oral anticoagulants (NOACs) for stroke prophylaxis in atrial fibrillation (AF) is increasing rapidly. We compared characteristics of AF patients initiated on NOACs versus vitamin K antagonists (VKAs). Methods: Using Danish nationwide registry data, we...... compared with a VKA [odds ratio (OR) 1.35, 95% confidence interval (CI) 1.28–1.43]. By contrast, patients with a history of myocardial infarction were less likely to be initiated on a NOAC compared with a VKA (OR 0.72, 95% CI 0.67–0.77). Conclusions: Atrial fibrillation patients who were initiated...

  2. 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.

  3. Atrial fibrillation and the 4P medicine.

    Science.gov (United States)

    Censi, Federica; Cianfrocca, Cinzia; Purificato, Ivana

    2013-01-01

    Although the paradigm of the 4P medicine - Predictive, Personalized, Preemptive, and Participatory - has been suggested several years ago, its application to atrial fibrillation is still far away. Given the increasing prevalence and incidence of this pathology it is the time to promote preventive strategies, by identifying the risk factors associated to life style and by incentivizing innovative diagnostic technologies. The promotion of the correct life style and of the use of diagnostic devices based on innovative and reliable technologies, represent a first step towards the full realization of the revolution of 4P medicine in atrial fibrillation.

  4. Atrial fibrillation and the 4P medicine

    Directory of Open Access Journals (Sweden)

    Federica Censi

    2013-09-01

    Full Text Available Although the paradigm of the 4P medicine - Predictive, Personalized, Preemptive, and Participatory - has been suggested several years ago, its application to atrial fibrillation is still far away. Given the increasing prevalence and incidence of this pathology it is the time to promote preventive strategies, by identifying the risk factors associated to life style and by incentivizing innovative diagnostic technologies. The promotion of the correct life style and of the use of diagnostic devices based on innovative and reliable technologies, represent a first step towards the full realization of the revolution of 4P medicine in atrial fibrillation.

  5. Distinction of salvaged and infarcted myocardium within the ischaemic area-at-risk with T2 mapping

    DEFF Research Database (Denmark)

    Hammer-Hansen, Sophia; Ugander, Martin; Hsu, Li-Yueh

    2014-01-01

    values from T2 maps and signal intensities on T2-weighted images were measured in the corresponding areas. RESULTS: At both imaging time points, the T2 of the salvaged myocardium was longer than of remote (66.0 ± 6.9 vs. 51.4 ± 3.5 ms, P ...AIM: Area-at-risk (AAR) measurements often rely on T2-weighted images, but subtle differences in T2 may be overlooked with this method. To determine the differences in oedema between salvaged and infarcted myocardium, we performed quantitative T2 mapping of the AAR. We also aimed to determine...... (14.7 ± 5.6 vs. 8.7 ± 5.1 ms, P = 0.02). CONCLUSIONS: T2 relaxation parameters are different in the infarcted and salvaged myocardium, and both are significantly longer than remote. Furthermore, the magnitude of increase in T2 was less in the salvaged myocardium after longer reperfusion, indicating...

  6. The contribution of nuclear medicine in the six months following a myocardium infarction

    International Nuclear Information System (INIS)

    Franken, Ph.R.

    2002-01-01

    The techniques of nuclear medicine allow to estimate the myocardial infarction size, to measure the ejection fraction and the ventricles volumes and to identify the presence of high-risk and viable myocardium. This information is essential to evaluate the important complications risks after an acute myocardial infarction, that is to say the infarction recurrence and the cardiac death coming from rhythm troubles or a left ventricle failure. (N.C.)

  7. Effect of hyperbaric oxygenation on carbohydrate metabolism protein synthesis in the myocardium during sustained hypodynamia

    Science.gov (United States)

    Makarov, G. A.

    1980-01-01

    Glycolysis and the intensity of protein synthesis were studied in 140 white male rats in subcellular fractions of the myocardium during 45 day hypodynamia and hyperbaric oxygenation. Hypodynamia increased: (1) the amount of lactic acids; (2) the amount of pyruvic acid; (3) the lactate/pyruvate coefficient; and (4) the activities of aldolase and lactate dehydrogenase. Hyperbaric oxygenation was found to have a favorable metabolic effect on the animals with hypodynamia.

  8. Imaging of the myocardium using {sup 18}F-FDG-PET/MRI

    Energy Technology Data Exchange (ETDEWEB)

    Ferda, Jiří, E-mail: ferda@fnplzen.cz [Clinic of the Imaging Methods, University Hospital Plzen, Alej Svobody 80, 304 60 Plzeň (Czech Republic); Hromádka, Milan, E-mail: hromadkam@fnplzen.cz [Department of Cardiology, University Hospital Plzen, Alej Svobody 80, 304 60 Plzeň (Czech Republic); Baxa, Jan, E-mail: baxaj@fnplzen.cz [Clinic of the Imaging Methods, University Hospital Plzen, Alej Svobody 80, 304 60 Plzeň (Czech Republic)

    2016-10-15

    Highlights: • The natural combination of the metabolic and structural information is the most important strenghtof myocardial PET/MRI. • Metabolic conversion to glycolysis is needed in the assesment ov the viable myocardium. • Metabolic conversion to the fatty acid metabolism is the crucial in the assesment of the ischemic memory and myocardial inflammation. - Abstract: The introduction of the integrated hybrid PET/MRI equipment creates the possibility to perform PET and MRI simultaneously. Depending on the clinical question, the metabolic conversion to glycolytic activity or beta-oxidation is performed before the application of FDG. Since FDG aids to evaluate the energetic metabolism of the myocytes and myocardial MRI reaches the imaging capabilities of perfusion and tissue characterization in the daily routine, FDG-PET/MRI looks to be a promising method of PET/MRI exploitation in cardiac imaging. When myocardial FDG uptake should be evaluated in association with the perfusion distribution, the cross-evaluation of FDG accumulation distribution and perfusion distribution pattern is necessary. The different scenarios may be used in the assessment of myocardium, the conversion to glycolytic activity is used in the imaging of the viable myocardium, but the glycolytic activity suppression might be used in the indications of the identification of injured myocardium by ischemia or inflammation. FDG-PET/MRI might aid to answer the clinical tasks according to the structure, current function and possibilities to improve the function in ischemic heart disease or to display the extent or activity of myocardial inflammation in sarcoidosis. The tight coupling between metabolism, perfusion and contractile function offers an opportunity for the simultaneous assessment of cardiac performance using one imaging modality.

  9. Effect of ethanol and the catalase inhibitor aminotriazole on lipid peroxidation in the rat myocardium

    International Nuclear Information System (INIS)

    Panchenko, L.F.; Pirozhkov, S.V.; Popova, S.V.; Antonenkov, V.D.

    1987-01-01

    The authors study the effect of chronic administration of ethanol and aminotriazole on the level of lipid peroxidation in the ray myocardium. The action of natural and artificial antioxidants on alcohol-induced lipid peroxidation also was studied. To determine the level of chemiluminescence, 1 ml of a sample of nuclear free homogenate or of the total fraction of particles was introduced for radioactivity measurement. After incubation the spontaneous weak luminescence was measured

  10. Posibilities of cardiac pacemaker use in paroxsysmal atrial fibrilation

    Directory of Open Access Journals (Sweden)

    Borut Kamenik

    2005-12-01

    Full Text Available Background: Prevention of atrial fibrillation is a big therapeutic challenge because of all known negative consequences of this the most frequent cardiac arrhythmia. Numerous of clinical studies showed bad control or ineffectiveness of antiarhythmic drugs. Nonfarmakological therapies like surgical treatment, radiofrequency ablation and atrial pacing are being tested. Effectiveness of atrial pacing in prevention of paroxysmal artial fibrillation has been documented in numerous prospective studies and is effective for a long time interval, but only for patients with bradicardic underlying cardiac rhythm. In Normocardic rhythm or normal AV conduction the effective Atrial fibrillation prevention was not proven. The mechanism of action is based on premature atrial complex suppression, reduction of dispersion of refractoriness after short-long cycles and reduction of interatrial conduction delay. The atrial stimulation site or multi-site atrial pacing could be effective in AF prevention when interatrial conduction delay is present; otherwise the difference is not significant.Conclusions: In bradicardic patient who has frequent paroxysms of atrial fibrillation, regardless if bradycardia is due to ineffective antiarrhythmic drug treathement, implantation of DDDR pacemaker with atrial prevention algorhythm is indicated. If the P-wave duration is >120 milliseconds multi-site atrial pacing or septal atrial pacing should be considered. Pacemaker diagnostic tools could be used for adequate start of anticoagulant therapy and control of effectiveness of anthyarhythmic drug therapy.

  11. Embolic Risk in Atrial Fibrillation that Arises from Hyperthyroidism

    Science.gov (United States)

    Traube, Elie; Coplan, Neil L.

    2011-01-01

    Atrial fibrillation, the most common cardiac complication of hyperthyroidism, occurs in an estimated 10% to 25% of overtly hyperthyroid patients. The prevalence of atrial fibrillation increases with age in the general population and in thyrotoxic patients. Other risk factors for atrial fibrillation in thyrotoxic patients include male sex, ischemic or valvular heart disease, and congestive heart failure. The incidence of arterial embolism or stroke in thyrotoxic atrial fibrillation is less clear. There are many reports of arterial thromboembolism associated with hyperthyroidism, including cases of young adults without coexisting risk factors other than thyrotoxic atrial fibrillation. The use of anticoagulative agents to prevent thromboembolic sequelae of thyrotoxic atrial fibrillation is controversial: national organizations provide conflicting recommendations in their practice guidelines. Herein, we review the medical literature and examine the evidence behind the recommendations in order to determine the best approach to thromboembolic prophylaxis in patients who have atrial fibrillation that is associated with hyperthyroidism. PMID:21720457

  12. Myocardium scanning with 201TL-chloride in ischemic heart disease

    International Nuclear Information System (INIS)

    Shejretova, E.; Beloev, J.; Kaloyanova, A.; Trindev, P.

    1979-01-01

    Results of myocardial scanning with 210 TL-chloride in ischemic herart disease are repoorted. An avearge dose of 500 microcurie and antero-posterior or lateral projection scanning with coloured registration are recommended. The scintigraphic pattern of the normal myocardium and the pathological changes, manifested by reduced isotope fixation, depending on the severity of the damage, are described. The diffuse pathological changes in the myocardium in ischemic heart disease are manifested by diffuse hypofixation of the radionuclide. The focal lesions in ischemic heart disease were manifested by characteristic changes: the infarctions of the posterior wall show a relatively clear scanographic picture on antero-posterior projection, with cold or cool zones in the median sections of the myocardium picture. Infarctions of the anterior myocardial wall, depending on how sizable they are, on antero-posterior projection are seen to occupy the lateral and central parts of the heart muscle. In the left oblique projection the pathologic process is projected frontally and centrally. (A.B.)

  13. Genetic modification of stem cells for improved therapy of the infarcted myocardium.

    Science.gov (United States)

    Haider, Husnain Kh; Mustafa, Anique; Feng, Yuliang; Ashraf, Muhammad

    2011-10-03

    The conventional treatment modalities for ischemic heart disease only provide symptomatic relief to the patient without repairing and regenerating the damaged myocardium. Stem cell transplantation has emerged as a promising alternative therapeutic approach for cardiovascular diseases. Stem cells possess the potential of differentiation to adopt morphofunctional cardiac and vasculogenic phenotypes to repopulate the scar tissue and restore regional blood flow in the ischemic myocardium. These beneficial therapeutic effects make stem cell transplantation the method of choice for the treatment of ischemic heart disease. The efficacy of stem cell transplantation may be augmented by genetic manipulation of the cells prior to transplantation. Not only will insertion of therapeutic transgene(s) into the stem cells support the survival and differentiation of cells in the unfavorable microenvironment of the ischemic myocardium, but also the genetically manipulated stem cells will serve as a source of the transgene expression product in the heart for therapeutic benefits. We provide an overview of the extensively studied stem cell types for cardiac regeneration, the various methods in which these cells have been genetically manipulated and rationale of genetic modification of stem cells for use in regenerative cardiovascular therapeutics.

  14. Metabolic shifts in the myocardium in the long-term effect of atmospheric pollution on the body

    Energy Technology Data Exchange (ETDEWEB)

    Tsapok, P I; Turdakin, P G; Barkov, L V; Ovcharuk, I N; Protod' iakonova, T N

    1981-04-01

    Metabolic shifts in the myocardium under conditions of long-term exposure of the body to air pollution were studied in experiments on albino rats. Study of the content of protein, RNA, DNA, glycogen, ATP, lactic and pyruvic acids and the activity of lactate dehydrogenase and creatine kinase in the heart muscle allowed the conclusion that the glycolytic processes are intensified, the bioenergic processes are inhibited and the synthesis of protein and RNA are increased in the myocardium of the experimental animals.

  15. Importance of scintigraphy of the myocardium with Csup(99m)-Tc-pyrophosphate in the diagnosis of myocardial ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Botnar' , V I; Dvoskina, I S [Inst. Kardiologii Vsesoyuznogo Kardiologicheskogo Nauchnogo Tsentra AN SSSR

    1983-10-01

    The following aspects of the method of scintigraphy of the myocardium with sup(99m)Tc-pyrophosphate as test sensitivity, possibility of estimating necrosis focus, prognostic importance of the method, scintigram dynamics in case of acute infarction, pyrophosphate accumulation in myocardial cells are considered. Advantages and prospects of the method for visualization of acute myocardium infarction focus and in cases of other pathological states are pointed out.

  16. 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

  17. 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.

  18. Left atrial low-voltage areas predict atrial fibrillation recurrence after catheter ablation in patients with paroxysmal atrial fibrillation.

    Science.gov (United States)

    Masuda, Masaharu; Fujita, Masashi; Iida, Osamu; Okamoto, Shin; Ishihara, Takayuki; Nanto, Kiyonori; Kanda, Takashi; Tsujimura, Takuya; Matsuda, Yasuhiro; Okuno, Shota; Ohashi, Takuya; Tsuji, Aki; Mano, Toshiaki

    2018-04-15

    Association between the presence of left atrial low-voltage areas and atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) has been shown mainly in persistent AF patients. We sought to compare the AF recurrence rate in paroxysmal AF patients with and without left atrial low-voltage areas. This prospective observational study included 147 consecutive patients undergoing initial ablation for paroxysmal AF. Voltage mapping was performed after PVI during sinus rhythm, and low-voltage areas were defined as regions where bipolar peak-to-peak voltage was low-voltage areas after PVI were observed in 22 (15%) patients. Patients with low-voltage areas were significantly older (72±6 vs. 66±10, plow-voltage areas than without (36% vs. 6%, pLow-voltage areas were independently associated with AF recurrence even after adjustment for the other related factors (Hazard ratio, 5.89; 95% confidence interval, 2.16 to 16.0, p=0.001). The presence of left atrial low-voltage areas after PVI predicts AF recurrence in patients with paroxysmal AF as well as in patients with persistent AF. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Remodelling of cellular excitation (reaction) and intercellular coupling (diffusion) by chronic atrial fibrillation represented by a reaction-diffusion system

    Science.gov (United States)

    Zhang, Henggui; Garratt, Clifford J.; Kharche, Sanjay; Holden, Arun V.

    2009-06-01

    Human atrial tissue is an excitable system, in which myocytes are excitable elements, and cell-to-cell electrotonic interactions are via diffusive interactions of cell membrane potentials. We developed a family of excitable system models for human atrium at cellular, tissue and anatomical levels for both normal and chronic atrial fibrillation (AF) conditions. The effects of AF-induced remodelling of cell membrane ionic channels (reaction kinetics) and intercellular gap junctional coupling (diffusion) on atrial excitability, conduction of excitation waves and dynamics of re-entrant excitation waves are quantified. Both ionic channel and gap junctional coupling remodelling have rate dependent effects on atrial propagation. Membrane channel conductance remodelling allows the propagation of activity at higher rates than those sustained in normal tissue or in tissue with gap junctional remodelling alone. Membrane channel conductance remodelling is essential for the propagation of activity at rates higher than 300/min as seen in AF. Spatially heterogeneous gap junction coupling remodelling increased the risk of conduction block, an essential factor for the genesis of re-entry. In 2D and 3D anatomical models, the dynamical behaviours of re-entrant excitation waves are also altered by membrane channel modelling. This study provides insights to understand the pro-arrhythmic effects of AF-induced reaction and diffusion remodelling in atrial tissue.

  20. 16-Cyclopentadienyl tricarbonyl 99mTc 16-oxo-hexadecanoic acid: synthesis and evaluation of fatty acid metabolism in mouse myocardium.

    Science.gov (United States)

    Lee, Byung Chul; Kim, Dong Hyun; Lee, Iljung; Choe, Yearn Seong; Chi, Dae Yoon; Lee, Kyung-Han; Choi, Yong; Kim, Byung-Tae

    2008-06-26

    We synthesized 16-cyclopentadienyl tricarbonyl 99mTc 16-oxo-hexadecanoic acid (99mTc-CpTT-16-oxo-HDA, 1) and investigated its potential as a radiotracer for evaluating fatty acid metabolism in myocardium. Radiotracer 1 was synthesized in 22.6 +/- 6.3% decay-corrected yield by a double ligand transfer reaction between the ferrocene adduct of methyl hexadecanoate ( 2) and Na99mTcO 4 in the presence of Cr(CO)6 and CrCl3, followed by hydrolysis of the methyl ester group. Radiotracer 1 was found to be chemically stable (99% at 6 h) when incubated in human serum. A tissue distribution study in mice showed that high radioactivity accumulated in heart (9.03%ID/g at 1 min and 5.41%ID/g at 5 min postinjection) with rapid clearance and that heart to blood uptake ratios increased with time (2.13 at 5 min and 3.76 at 30 min postinjection). Metabolite analysis of the heart tissues using a simple extraction method showed that 99mTc-CpTT-4-oxo-butyric acid was detected as the major radioactive metabolite by HPLC, suggesting that 1 is metabolized to 99mTc-CpTT-4-oxo-butyric acid via beta-oxidation in myocardium.

  1. Valsartan Reduced Atrial Fibrillation Susceptibility by Inhibiting Atrial Parasympathetic Remodeling through MAPKs/Neurturin Pathway

    Directory of Open Access Journals (Sweden)

    Lei Liu

    2015-07-01

    Full Text Available Background/Aims: Angiotensin II receptor blockers (ARBs have been proved to be effective in preventing atrial structural and electrical remodelinq in atrial fibrillation (AF. Previous studies have shown that parasympathetic remodeling plays an important role in AF. However, the effects of ARBs on atrial parasympathetic remodeling in AF and the underlying mechanisms are still unknown. Methods: Canines were divided into sham-operated, pacing and valsartan + pacing groups. Rats and HL-1 cardiomyocytes were divided into control, angiotensin II (Ang II and Ang II + valsartan groups, respectively. Atrial parasympathetic remodeling was quantified by immunocytochemical staining with anti-choline acetyltransferase (ChAT antibody. Western blot was used to analysis the protein expression of neurturin. Results: Both inducibility and duration were increased in chronic atrial rapid-pacing canine model, which was significantly inhibited by the treatment with valsartan. The density of ChAT-positive nerves and the protein level of neurturin in the atria of pacing canines were both increased than those in sham-operated canines. Ang II treatment not only induced atrial parasympathetic remodeling in rats, but also up-regulated the protein expression of neurturin. Valsartan significantly prevented atrial parasympathetic remodeling, and suppressed the protein expression of neurturin. Meanwhile, valsartan inhibited Ang II -induced up-regulation of neurturin and MAPKs in cultured cardiac myocytes. Inhibition of MAPKs dramatically attenuated neurturin up-regulation induced by Ang II. Conclusion: Parasympathetic remodeling was present in animals subjected to rapid pacing or Ang II infusion, which was mediated by MAPKs/neurturin pathway. Valsartan is able to prevent atrial parasympathetic remodeling and the occurrence of AF via inhibiting MAPKs/neurturin pathway.

  2. Valsartan Reduced Atrial Fibrillation Susceptibility by Inhibiting Atrial Parasympathetic Remodeling through MAPKs/Neurturin Pathway.

    Science.gov (United States)

    Liu, Lei; Geng, Jianqiang; Zhao, Hongwei; Yun, Fengxiang; Wang, Xiaoyu; Yan, Sen; Ding, Xue; Li, Wenpeng; Wang, Dingyu; Li, Jianqiang; Pan, Zhenwei; Gong, Yongtai; Tan, Xiangyang; Li, Yue

    2015-01-01

    Angiotensin II receptor blockers (ARBs) have been proved to be effective in preventing atrial structural and electrical remodelinq in atrial fibrillation (AF). Previous studies have shown that parasympathetic remodeling plays an important role in AF. However, the effects of ARBs on atrial parasympathetic remodeling in AF and the underlying mechanisms are still unknown. Canines were divided into sham-operated, pacing and valsartan + pacing groups. Rats and HL-1 cardiomyocytes were divided into control, angiotensin II (Ang II) and Ang II + valsartan groups, respectively. Atrial parasympathetic remodeling was quantified by immunocytochemical staining with anti-choline acetyltransferase (ChAT) antibody. Western blot was used to analysis the protein expression of neurturin. Both inducibility and duration were increased in chronic atrial rapid-pacing canine model, which was significantly inhibited by the treatment with valsartan. The density of ChAT-positive nerves and the protein level of neurturin in the atria of pacing canines were both increased than those in sham-operated canines. Ang II treatment not only induced atrial parasympathetic remodeling in rats, but also up-regulated the protein expression of neurturin. Valsartan significantly prevented atrial parasympathetic remodeling, and suppressed the protein expression of neurturin. Meanwhile, valsartan inhibited Ang II -induced up-regulation of neurturin and MAPKs in cultured cardiac myocytes. Inhibition of MAPKs dramatically attenuated neurturin up-regulation induced by Ang II. Parasympathetic remodeling was present in animals subjected to rapid pacing or Ang II infusion, which was mediated by MAPKs/neurturin pathway. Valsartan is able to prevent atrial parasympathetic remodeling and the occurrence of AF via inhibiting MAPKs/neurturin pathway. © 2015 S. Karger AG, Basel.

  3. 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....

  4. Left Atrial Decompression by Percutaneous Left Atrial Venting Cannula Insertion during Venoarterial Extracorporeal Membrane Oxygenation Support

    Directory of Open Access Journals (Sweden)

    Ha Eun Kim

    2016-06-01

    Full Text Available Patients with venoarterial extracorporeal membrane oxygenation (ECMO frequently suffer from pulmonary edema due to left ventricular dysfunction that accompanies left heart dilatation, which is caused by left atrial hypertension. The problem can be resolved by left atrium (LA decompression. We performed a successful percutaneous LA decompression with an atrial septostomy and placement of an LA venting cannula in a 38-month-old child treated with venoarterial ECMO for acute myocarditis.

  5. Atrial electrogram quality in single-pass defibrillator leads with floating atrial bipole in patients with permanent atrial fibrillation and cardiac resynchronization therapy.

    Science.gov (United States)

    Sticherling, Christian; Müller, Dirk; Schaer, Beat A; Krüger, Silke; Kolb, Christof

    2018-03-27

    Many patients receiving cardiac resynchronization therapy (CRT) suffer from permanent atrial fibrillation (AF). Knowledge of the atrial rhythm is important to direct pharmacological or interventional treatment as well as maintaining AV-synchronous biventricular pacing if sinus rhythm can be restored. A single pass single-coil defibrillator lead with a floating atrial bipole has been shown to obtain reliable information about the atrial rhythm but has never been employed in a CRT-system. The purpose of this study was to assess the feasibility of implanting a single coil right ventricular ICD lead with a floating atrial bipole and the signal quality of atrial electrograms (AEGM) in CRT-defibrillator recipients with permanent AF. Seventeen patients (16 males, mean age 73 ± 6 years, mean EF 25 ± 5%) with permanent AF and an indication for CRT-defibrillator placement were implanted with a designated CRT-D system comprising a single pass defibrillator lead with a atrial floating bipole. They were followed-up for 103 ± 22 days using remote monitoring for AEGM transmission. All patients had at last one AEGM suitable for atrial rhythm diagnosis and of 100 AEGM 99% were suitable for visual atrial rhythm assessment. Four patients were discharged in sinus rhythm and one reverted to AF during follow-up. Atrial electrograms retrieved from a single-pass defibrillator lead with a floating atrial bipole can be reliably used for atrial rhythm diagnosis in CRT recipients with permanent AF. Hence, a single pass ventricular defibrillator lead with a floating bipole can be considered in this population. Copyright © 2018 Indian Heart Rhythm Society. Production and hosting by Elsevier B.V. All rights reserved.

  6. 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. 

  7. Angiogenesis with intramyocardial administration of basic fibroblast growth factor in canine ischemic myocardium

    International Nuclear Information System (INIS)

    Sun Lijun; Liu Ying; Zhao Haitao; Huan Yi; Ge Yali; Gao Fabao

    2004-01-01

    Objective: To evaluate the effect of intramyocardial administration of basic fibroblast growth factor on angiogenesis of infarcted myocardium in dogs. Methods: Twenty-four mongrel dogs were randomized into control group and therapeutic group. Acute myocardial infarction was made by ligation of the left anterior descending coronary artery distal to its first diagonal branch. As soon as coronary artery was occluded, 50 mg of basic fibroblast growth factor in 15 ml of saline was injected into the infarcted and border zone in therapeutic group, whereas 15 ml saline alone was used in the same way in control dogs. Every 3 dogs in each group was studied on the 1 st day, the 3 rd day, the 10 th day, and the 17 th day, respectively. Electron microscope was used to observe the growth of capillaries. Angiogenesis was evaluated by immunohistochemical studies with VIII factor. With sensitivity encoded technique, cine MR and MR perfusion imaging were performed on each dog within 3 hours after surgery and before euthanasia to evaluate cardiac function and the characteristics of myocardial perfusion. Results: In therapeutic group, LVEF improved markedly since the 10 th day (on the 10 th day: control group 24.09 ± 3.32, therapeutic group 45.71 ± 6.27; on the 17 th day: control group 31.46 ± 4.60, therapeutic group 53.46 ± 5.24). Hypoenhancement on first pass and hyperenhancement on delayed phase appeared in infarcted myocardium. There were significant differences for the time of upslope, peak time of signal intensity, upslope curves ratio, and contrast enhancement ratio between infarcted and normal myocardium. The size of infarcted myocardium was markedly decreased on the 17 th day [control group (9.04 ± 1.59)%, therapeutic group (4.07 ± 1.20)%]. The capillaries grew actively in therapeutic group and microvessel density was higher in therapeutic group than in control group except the first day (control group and therapeutic group respectively on the 3 rd day: 92.3 ± 11

  8. Channeled Scaffolds for Engineering Myocardium with Mechanical Stimulation

    Science.gov (United States)

    Zhang, Ting; Wan, Leo Q.; Xiong, Zhuo; Marsano, Anna; Maidhof, Robert; Park, Miri; Yan, Yongnian; Vunjak-Novakovic, Gordana

    2011-01-01

    The characteristics of the matrix (composition, structure, mechanical properties) and external culture environment (pulsatile perfusion, physical stimulation) are critically important for engineering functional myocardial tissue. We report the development of chitosan-collagen scaffolds with micro-pores and an array of parallel channels (~200 μm in diameter) that were specifically designed for cardiac tissue engineering with mechanical stimulation. The scaffolds were designed to have the structural and mechanical properties similar to those of the native human heart matrix. Scaffolds were seeded with neonatal rat heart cells and subjected to dynamic tensile stretch using a custom-designed bioreactor. The channels enhanced oxygen transport and facilitated the establishment of cell connections within the construct. The myocardial patches (14 mm in diameter, 1–2 mm thick) consisted of metabolically active cells and started to contract synchronously after 3 days of culture. Mechanical stimulation with high tensile stresses promoted cell alignment, elongation, and the expression of connexin-43 (Cx-43). This study confirms the importance of scaffold design and mechanical stimulation for the formation of contractile cardiac constructs. PMID:22081518

  9. 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...

  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. Atrial fibrillation in the Middle East

    DEFF Research Database (Denmark)

    Al-Shamkhani, Warkaa; Ayetey, Harold; Lip, Gregory Y H

    2018-01-01

    INTRODUCTION: Atrial fibrillation (AF) is the commonest persistent cardiac arrhythmia with an estimated incidence rate of between 1.5-2% and an important cause of strokes. Few epidemiological studies and clinical trials on the management of AF have been conducted outside Europe and North America...

  12. An "account" of digitalis and atrial fibrillation

    NARCIS (Netherlands)

    Meijler, F.L.

    This review deals with the mechanisms by which digitalis exerts its "opium-Iike" action on the ventricular rate in patients with atrial fibrillation. To understand the effect of digitalis on ventricular rate and rhythm, it is essential to learn more about the basic electrophysiologic

  13. Modulation of ephrinB2 leads to increased angiogenesis in ischemic myocardium and endothelial cell proliferation

    International Nuclear Information System (INIS)

    Mansson-Broberg, Agneta; Siddiqui, Anwar J.; Genander, Maria; Grinnemo, Karl-Henrik; Hao Xiaojin; Andersson, Agneta B.; Waerdell, Eva; Sylven, Christer; Corbascio, Matthias

    2008-01-01

    Eph/ephrin signaling is pivotal in prenatal angiogenesis while its potential role in postnatal angiogenesis largely remains to be explored. Therefore its putative angiogenic and therapeutic effects were explored in endothelium and in myocardial ischemia. In culture of human aortic endothelial cells the fusion protein ephrinB2-Fc induced cell proliferation (p < 0.0005) and in the murine aortic ring model ephrinB2-Fc induced increased sprouting (p < 0.05). Myocardial infarction was induced by ligation of the left anterior descending artery in mouse. During the following 2 weeks mRNA of the receptor/ligand pair EphB4/ephrinB2 was expressed dichotomously (p < 0.05) and other Eph/ephrin pairs were expressed to a lesser degree. Twenty-four hours after intraperitoneal administration of ephrinB2-Fc it was detected in abundance throughout the myocardium along capillaries, showing signs of increased mitosis. After 4 weeks the capillary density was increased 28% in the periinfarcted area (p < 0.05) to a level not different from healthy regions of the heart where no change was observed. These results implicate that EphB4/ephrinB2 is an important signaling pathway in ischemic heart disease and its modulation may induce therapeutic angiogenesis

  14. 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.

  15. [Effect of benazepril on atrial cytoskeleton remodeling in the canine atrial fibrillation models].

    Science.gov (United States)

    Liu, Li; Qu, Xiu-Fen; Yu, Yang; Bai, Bing; Huang, Yong-Lin

    2009-10-20

    To investigate the effect of benazepril on atrial cytoskeleton remodeling in atrial fibrillation (AF) canines induced by chronic rapid atrial pacing (RAP). Twenty canines were randomly divided into 3 groups: (1) Sham-operated group without RAP; (2) AF group: AF established by RAP at 600 beats per minute for 6 weeks; (3) Benazepril group: benazepril was dosed from 1 week pre-pacing to 6 weeks post-pacing. The diameter of atrial cardiomyocyte was measured, collagen volume fraction (CVF) analyzed by Masson staining and the expression and distribution of desmin were assayed by immunohistochemistry. RT-PCR method was used to semi-quantify the mRNA expression of beta-tubulin and desmin. The diameter of atrial cardiomyocyte increased in AF group [LA:(27.9 +/- 3.8) microm; RA: (26.8 +/- 3.2) microm] and benazepril group[LA: (25.1 +/- 3.4) microm; RA: (25.2 +/- 3.5) microm] than sham-operated group [LA: (19.6 +/- 2.9) microm; RA: (18.7 +/- 2.6) microm] (P benazepril group than AF group [LA: (11.3 +/- 0.8)% vs (16.9 +/- 1.1)%, RA: (10.9 +/- 0.8)% vs (15.7 +/- 2.3)%, P benazepril group than AF group (P benazepril group than AF group (LA:0.8 +/- 0.4 vs 1.0 +/- 0.3, 0.7 +/- 0.3 vs 0.9 +/- 0.4; RA:0.7 +/- 0.3 vs 1.0 +/- 0.6, 0.7 +/- 0.3 vs 1.1 +/- 0.3, P Benazepril can favorably improve atrial cytoskeleton remodeling in the canine atrial fibrillation model.

  16. 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....

  17. 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

    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

  18. [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.

  19. 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...... of the zebrafish kcnk3a and kcnk3b genes and cardiac phenotypes were evaluated using videomicroscopy. Combined kcnk3a and kcnk3b knockdown in 72 hour post fertilization embryos resulted in lower heart rate (p

  20. Role of spiral wave pinning in inhomogeneous active media in the termination of atrial fibrillation by electrical cardioversion.

    Science.gov (United States)

    Kuklik, Pawel; Wong, Christopher X; Brooks, Anthony G; Zebrowski, Jan Jacek; Sanders, Prashanthan

    2010-03-01

    Atrial fibrillation is the most common type of arrhythmia to affect humans. One of the treatment modalities for atrial fibrillation is an electrical cardioversion. Electrical cardioversion can result in one of three outcomes: an immediate termination of arrhythmic activity, a delayed termination or unsuccessful termination. The mechanism of delayed termination is unknown. Here we present a model of an atrial fibrillation as a coexistence of several spiral waves pinned to the inhomogeneities in active media. We show that in inhomogeneous system delayed termination can be explained as the unpinning of a spiral wave from inhomogeneities and its termination after collision with the edge of the system. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  1. 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.

  2. Cardiorespiratory interactions in patients with atrial flutter.

    Science.gov (United States)

    Masè, Michela; Disertori, Marcello; Ravelli, Flavia

    2009-01-01

    Respiratory sinus arrhythmia (RSA) is generally known as the autonomically mediated modulation of the sinus node pacemaker frequency in synchrony with respiration. Cardiorespiratory interactions have been largely investigated during sinus rhythm, whereas little is known about interactions during reentrant arrhythmias. In this study, cardiorespiratory interactions at the atrial and ventricular level were investigated during atrial flutter (AFL), a supraventricular arrhythmia based on a reentry, by using cross-spectral analysis and computer modeling. The coherence and phase between respiration and atrial (gamma(AA)(2), phi(AA)) and ventricular (gamma(RR)(2), phi(RR)) interval series were estimated in 20 patients with typical AFL (68.0 +/- 8.8 yr) and some degree of atrioventricular (AV) conduction block. In all patients, atrial intervals displayed oscillations strongly coupled and in phase with respiration (gamma(AA)(2)= 0.97 +/- 0.05, phi(AA) = 0.71 +/- 0.31 rad), corresponding to a paradoxical lengthening of intervals during inspiration. The modulation pattern was frequency independent, with in-phase oscillations and short time delays (0.40 +/- 0.15 s) for respiratory frequencies in the range 0.1-0.4 Hz. Ventricular patterns were affected by AV conduction type. In patients with fixed AV conduction, ventricular intervals displayed oscillations strongly coupled (gamma(RR)(2)= 0.97 +/- 0.03) and in phase with respiration (phi(RR) = 1.08 +/- 0.80 rad). Differently, in patients with variable AV conduction, respiratory oscillations were secondary to Wencheback rhythmicity, resulting in a decreased level of coupling (gamma(RR)(2)= 0.50 +/- 0.21). Simulations with a simplified model of AV conduction showed ventricular patterns to originate from the combination of a respiratory modulated atrial input with the functional properties of the AV node. The paradoxical frequency-independent modulation pattern of atrial interval, the short time delays, and the complexity of

  3. Sustained nonoxidative glucose utilization and depletion of glycogen in reperfused canine myocardium

    International Nuclear Information System (INIS)

    Schwaiger, M.; Neese, R.A.; Araujo, L.

    1989-01-01

    Ischemically injured reperfused myocardium is characterized by increased 18F-fluorodeoxyglucose uptake as demonstrated by positron emission tomography. To elucidate the metabolic fate of exogenous glucose entering reperfused myocardium, D-[6-14C] glucose and L-[U-13C] lactate were used to determine glucose uptake, glucose oxidation and the contribution of exogenous glucose to lactate production. The pathologic model under investigation consisted of a 3 h balloon occlusion of the left anterior descending coronary artery followed by 24 h of reperfusion in canine myocardium. The extent and severity of myocardial injury after the ischemia and reperfusion were assessed by histochemical evaluation (triphenyltetrazolium chloride and periodic acid-Schiff stains). Thirteen intervention and four control dogs were studied. The glucose uptake in the occluded/reperfused area was significantly enhanced compared with that in control dogs (0.40 +/- 0.14 versus 0.15 +/- 0.10 mumol/ml, respectively). In addition, a significantly greater portion of the glucose extracted immediately entered glycolysis in the intervention group (75%) than in the control dogs (33%). The activity of the nonoxidative glycolytic pathway was markedly increased in the ischemically injured reperfused area, as evidenced by the four times greater lactate release in this area compared with the control value. The dual carbon-labeled isotopes showed that 57% of the exogenous glucose entering glycolysis was being converted to lactate. Exogenous glucose contributed to greater than 90% of the observed lactate production. This finding was confirmed by the histochemical finding of sustained glycogen depletion in the occlusion/reperfusion area. The average area of glycogen depletion (37%) significantly exceeded the average area of necrosis

  4. Metabolic syndrome impairs notch signaling and promotes apoptosis in chronically ischemic myocardium.

    Science.gov (United States)

    Elmadhun, Nassrene Y; Sabe, Ashraf A; Lassaletta, Antonio D; Chu, Louis M; Kondra, Katelyn; Sturek, Michael; Sellke, Frank W

    2014-09-01

    Impaired angiogenesis is a known consequence of metabolic syndrome (MetS); however, the mechanism is not fully understood. Recent studies have shown that the notch signaling pathway is an integral component of cardiac angiogenesis. We tested, in a clinically relevant swine model, the effects of MetS on notch and apoptosis signaling in chronically ischemic myocardium. Ossabaw swine were fed either a regular diet (control [CTL], n = 8) or a high-cholesterol diet (MetS, n = 8) to induce MetS. An ameroid constrictor was placed to induce chronic myocardial ischemia. Eleven weeks later, the wine underwent cardiac harvest of the ischemic myocardium. Downregulation of pro-angiogenesis proteins notch2, notch4, jagged2, angiopoietin 1, and endothelial nitric oxide synthase were found in the MetS group compared with the CTL group. Also, upregulation of pro-apoptosis protein caspase 8 and downregulation of anti-angiogenesis protein phosphorylated forkhead box transcription factor 03 and pro-survival proteins phosphorylated P38 and heat shock protein 90 were present in the MetS group. Cell death was increased in the MetS group compared with the CTL group. Both CTL and MetS groups had a similar arteriolar count and capillary density, and notch3 and jagged1 were both similarly concentrated in the smooth muscle wall. MetS in chronic myocardial ischemia significantly impairs notch signaling by downregulating notch receptors, ligands, and pro-angiogenesis proteins. MetS also increases apoptosis signaling, decreases survival signaling, and increases cell death in chronically ischemic myocardium. Although short-term angiogenesis appears unaffected in this model of early MetS, the molecular signals for angiogenesis are impaired, suggesting that inhibition of notch signaling might underlie the decreased angiogenesis in later stages of MetS. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  5. Kinetics of thallium-201 in reperfused canine myocardium after coronary artery occlusion

    International Nuclear Information System (INIS)

    Okada, R.D.

    1984-01-01

    To study the kinetics of thallium-201 in nonsalvaged acutely infarcted myocardium and salvaged myocardium, the tracer was administered after experimental left anterior descending coronary artery reperfusion 2 hours after occlusion. In 19 dogs, thallium activity was then monitored for 4 hours in the reperfused anterior wall and normal posterior wall using miniature cadmium telluride radiation detectors. After sacrifice, 13 of the dogs were found to have an infarcted anterior wall by triphenyltetrazolium-chloride staining. In these dogs, mean (+/- standard deviation) fractional 4 hour thallium clearance was 0.33 +/- 0.08 for the infarct zone and 0.15 +/- 0.06 for the normal control zone (p less than 0.001). When computer-modeled, the clearance curve from the infarct zone was biexponential. The second exponential clearance curve from the infarct zone began 19.1 +/- 3.2 minutes after tracer administration, and was indistinguishable from the monoexponential clearance curve from the normal control zone. Thallium clearance from the blood pool was triexponential, the final exponential clearance curve being indistinguishable from the normal control zone clearance curve. Six dogs were found to have a salvaged noninfarcted anterior wall by triphenyltetrazolium-chloride staining. In these dogs, mean fractional 4 hour thallium clearance was 0.20 +/- 0.07 for the reperfused zone, and 0.19 +/- 0.08 for the normal control zone (p . NS). When computer-modeled, clearance curves for the reperfused and control zones were monoexponential. The monoexponential clearance curve for the salvaged reperfused zone was indistinguishable from the monoexponential clearance curve for normal myocardium

  6. Development of an in vivo method for determining material properties of passive myocardium

    Directory of Open Access Journals (Sweden)

    Espen Remme

    2004-10-01

    Full Text Available Calculation of mechanical stresses and strains in the left ventricular (LV myocardium by the finite element (FE method relies on adequate knowledge of the material properties of myocardial tissue. In this paper we present a model-based estimation procedure to characterize the stress-strain relationship in passive LV myocardium. A 3D FE model of the LV myocardium was used, which included morphological fiber and sheet structure and a nonlinear orthotropic constitutive law with different stiffness in the fiber, sheet and sheet-normal directions. The estimation method was based on measured wall strains. We analyzed the method's ability to estimate the material parameters by generating a set of synthetic strain data by simulating the LV inflation phase with known material parameters. In this way we were able to verify the correctness of the solution and to analyze the effects of measurement and model error on the solution accuracy and stability. A sensitivity analysis was performed to investigate the observability of the material parameters and to determine which parameters to estimate. The results showed a high degree of coupling between the parameters governing the stiffness in each direction. Thus, only one parameter in each of the three directions was estimated. For the tested magnitudes of added noise and introduced model errors, the resulting estimated stress-strain characteristics in the fiber and sheet directions converged with good accuracy to the known relationship. The sheet-normal stress-strain relationship had a higher degree of uncertainty as more noise was added and model error was introduced.

  7. 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 differe...... 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....

  8. Extreme variation in the atrial septation of caecilians (Amphibia: Gymnophiona)

    Science.gov (United States)

    de Bakker, Desiderius M; Wilkinson, Mark; Jensen, Bjarke

    2015-01-01

    Caecilians (order Gymnophiona) are elongate, limbless, snake-like amphibians that are the sister-group (closest relatives) of all other recent amphibians (frogs and salamanders). Little is known of their cardiovascular anatomy and physiology, but one nearly century old study suggests that Hypogeophis (family Indotyphlidae), commonly relied upon as a representative caecilian species, has atrial septation in the frontal plane and more than one septum. In contrast, in other vertebrates there generally is one atrial septum in the sagittal plane. We studied the adult heart of Idiocranium (also Indotyphlidae) using immunohistochemistry and confirm that the interatrial septum is close to the frontal plane. Additionally, a parallel right atrial septum divides three-fourths of the right atrial cavity of this species. Idiocranium embryos in the Hill collection reveal that atrial septation initiates in the sagittal plane as in other tetrapods. Late developmental stages, however, see a left-ward shift of visceral organs and a concordant rotation of the atria that reorients the atrial septa towards the frontal plane. The gross anatomies of species from six other caecilian families reveal that (i) the right atrial septum developed early in caecilian evolution (only absent in Rhinatrematidae) and that (ii) rotation of the atria evolved later and its degree varies between families. In most vertebrates a prominent atrial trabeculation associates with the sinuatrial valve, the so-called septum spurium, and the right atrial septum seems homologous to this trabeculation but much more developed. The right atrial septum does not appear to be a consequence of body elongation because it is absent in some caecilians and in snakes. The interatrial septum of caecilians shares multiple characters with the atrial septum of lungfishes, salamanders and the embryonic septum primum of amniotes. In conclusion, atrial septation in caecilians is based on evolutionarily conserved structures but

  9. The effect of percutaneous transmyocardial laser revascularization on left ventricular function in a porcine model of hibernating myocardium

    International Nuclear Information System (INIS)

    Almeda, Francis Q.; Glock, Dana; Sandelski, Joanne; Ibrahim, Osama; Macioch, James E.; Allen, Trisha; Dainauskas, John R.; Parrillo, Joseph E.; Snell, R. Jeffrey; Schaer, Gary L.

    2004-01-01

    Background: Hibernating myocardium is defined as a state of persistently impaired myocardial function at rest due to reduced coronary blood flow that can partially or completely be restored to normal if the myocardial oxygen supply/demand relationship is favorably altered. Percutaneous laser revascularization (PMR) is an emerging catheter-based technique that involves creating channels in the myocardium, directly through a percutaneous approach with a laser delivery system, and has been shown to reduce symptoms in patients with severe refractory angina; however, its effect on improving regional wall motion abnormalities in hibernating myocardium has not been clearly established. We sought to determine the effect of PMR using the Eclipse System (Cardiogenesis) on left ventricular function in a porcine model of hibernating myocardium. Methods: A model of hibernating myocardium was created by placement of an ameroid constrictor in the proximal left anterior descending artery of a 35 kg male Yorkshire pig. The presence of hibernating myocardium was confirmed with dobutamine stress echocardiography (DSE) and defined as severe hypocontractility at rest, with an improvement in systolic wall thickening with low-dose dobutamine in myocardial regions with a subsequent deterioration in function at peak stress (biphasic response). After the demonstration of hibernating myocardium, PMR was performed in the area of hypocontractile function, and the serial echocardiography was performed. The echocardiograms were reviewed by an experienced echocardiologist blinded to the results, and regional wall motion was assessed using the American Society of Echocardiography Wall Motion Score. Six weeks after PMR, the animal was sacrificed and the heart sent for histopathologic studies. Results: A comparison of the regional wall motion function of the area distal to the ameroid constrictor and in the contralateral wall at baseline, post-ameroid placement, and post-PMR was performed

  10. Adaptation of the cardiovascular system to postinfarction cardiosclerosis in rats with congenital adrenoreactivity of the myocardium.

    Science.gov (United States)

    Usacheva, M A; Popkova, E V; Smirnova, E A; Saltykova, V A; Belkina, L M

    2007-12-01

    Three months after myocardial infarction the severity of heart failure and size of postinfarction scars in August rats with inherently reduced adrenoreactivity of the myocardium were similar to those in Wistar rats. The mortality rate in August rats was 2.5-fold lower than in Wistar rats. During the postinfarction period, myocardial adrenoreactivity in August rats remained lower, while the efficiency of cardiac function was 62% higher than in Wistar rats. The incidence of epinephrine-induced arrhythmias in August rats was much lower than in Wistar rats.

  11. Method for radio imaging the myocardium of mammals using radio-labelled lipophil cations

    International Nuclear Information System (INIS)

    1984-01-01

    The invention relates to a method for the radio imaging of myocardia of mammals by concentrating a radiolabelled cation in myocardial tissue and by producing a radiograph using imaging techniques. According to the invention, it is found that a group of substances shows a preference to myocardial tissues upon intravenous injection in mammals. The characteristic of the invention is that radiolabelled quaternary ammonium, quaternary phosphorous or quaternary arsenic compounds with at least two aryl groups are intravenously injected. These substances provide a sufficiently high radioactivity giving an approved diagnostic image of the myocardium. (G.J.P.)

  12. Entropy measurements in paroxysmal and persistent atrial fibrillation

    International Nuclear Information System (INIS)

    Cervigón, R; Moreno, J; Pérez-Villacastín, J; Reilly, R B; Millet, J; Castells, F

    2010-01-01

    Recent studies on atrial fibrillation (AF) have identified different activation patterns in paroxysmal and persistent AF. In this study, bipolar intra-atrial registers from 28 patients (14 paroxysmal AF and 14 persistent AF) were analyzed in order to find out regional differences in the organization in both types of arrhythmias. The organization of atrial electrical activity was assessed in terms of nonlinear parameters, such as entropy measurements. Results showed differences between the atrial chambers with a higher disorganization in the left atrium in paroxysmal AF patients and a more homogenous behavior along the atria in persistent AF patients

  13. [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.

  14. A patient with type I CD36 deficiency whose myocardium accumulated 123I-BMIPP after 4 years.

    Science.gov (United States)

    Ito, K; Sugihara, H; Tanabe, T; Zen, K; Hikosaka, T; Adachi, Y; Katoh, S; Azuma, A; Nakagawa, M

    2001-06-01

    A 73-year-old man with aortic regurgitation was examined by 123I-alpha-methyl-p-iodophenylpentadecanoic acid (BMIPP) myocardial single photon emission computed tomography (SPECT) in 1995. Myocardial accumulation was not evident on either the early or the delayed image obtained 15 minutes and 3 hours, respectively, after injecting 123I-BMIPP. Flow cytometric analysis of CD36 expression in monocytes and platelets identified a type I CD36 deficiency. The patient was hospitalized for severe heart failure in 1999. Upon admission, the cardiothoracic ratio on chest X-rays was 73%, and the left ventricular end-diastolic diameter on echocardiograms was enlarged to 77 mm. On the second day, we performed 123I-BMIPP myocardial SPECT. Myocardial accumulation was evident in the delayed, but not in the early image. We repeated 123I-BMIPP myocardial SPECT on the 10th day after admission. Myocardial accumulation was evident on both early and delayed images. 99mTc-tetrofosmin myocardial SPECT was immediately performed after 123I-BMIPP myocardial SPECT to distinguish myocardial from pooling images in the left ventricle, but, because the images from both 99Tc-tetrofosmin and 123I-BMIPP myocardial SPECT were idential, we considered that the 123I-BMIPP myocardial SPECT images reflected the actual myocardial condition. The CD36 molecule transports long-chain fatty acid (LCFA) on the myocardial membrane, but 123I-BMIPP scintigraphy does not show any myocardial accumulation in patients with type I CD36 deficiency, indicating that myocardial LCFA uptake occurs through CD36 on the human myocardial membrane. Even though our patient had type I CD36 deficiency, BMIPP was uptaken by the myocardium during heart failure, suggesting a variant pathway on the human myocardial membrane for LCFA uptake.

  15. Endurance Sport Practice and Atrial Fibrillation

    OpenAIRE

    Calvo, Naiara; Mont, Lluis

    2010-01-01

    Atrial fibrillation (AF) is the most common cardiac rhythm disorder in clinical practice, with an estimated prevalence of 0.4% to 1% in the general population, increasing with age to 8% in those older than 80 years. The recognized risk factors for developing AF include age, hypertension, structural heart disease, diabetes mellitus, and hyperthyroidism. However, the etiology remains unclear in a significant number of patients younger than age 60 in whom no cardiovascular disease or any other k...

  16. Red Wine, Resveratrol and Atrial Fibrillation

    OpenAIRE

    Stephan, Laura Siga; Almeida, Eduardo Dytz; Markoski, Melissa Medeiros; Garavaglia, Juliano; Marcadenti, Aline

    2017-01-01

    Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as a...

  17. Acute atrial fibrillation during dengue hemorrhagic fever

    Directory of Open Access Journals (Sweden)

    Henrique Horta Veloso

    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.

  18. 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.

  19. Association Between Left Atrial Compression And Atrial Fibrillation: A Case Presentation And A Short Review Of Literature.

    Science.gov (United States)

    Ahmed, Niloy; Carlos, Morales-Mangual; Moshe, Gunsburg; Yitzhak, Rosen

    2016-01-01

    This case report describes a patient who developed palpitations and chest pain and was found to be in atrial fibrillation, which was likely due to the presence of an extra-cardiac mass. This was compressing the left atrium. The mass was related to small cell carcinoma, which decreased significantly in size after chemotherapy. Resolution of the atrial fibrillation correlated temporally with reduction in the size of the mass and alleviation of the left atrial compression.

  20. Atrial Fibrillation in Eight New World Camelids.

    Science.gov (United States)

    Bozorgmanesh, R; Magdesian, K G; Estell, K E; Stern, J A; Swain, E A; Griffiths, L G

    2016-01-01

    There is limited information on the incidence of clinical signs, concurrent illness and treatment options for atrial fibrillation (AF) in New World Camelids (NWC). Describe clinical signs and outcome of AF in NWC. Eight New World Camelids admitted with AF. A retrospective observational study of camelids diagnosed with AF based on characteristic findings on electrocardiogram (ECG). All animals had an irregularly irregular heart rhythm detected on physical examination and 4 cases had obtunded mentation on admission. Three camelids were diagnosed with AF secondary to oleander intoxication, 3 animals had underlying cardiovascular disease, 1 was diagnosed with lone AF and 1 had AF diagnosed on examination for a urethral obstruction. Five of eight animals survived to discharge and nonsurvivors consisted of animals which died or were euthanized as a result of cardiovascular disease (2/8) or extra-cardiac disease unrelated to the AF (1/8). Atrial fibrillation occurs in NWC in association with cardiovascular disease, extra-cardiac disease or as lone AF. Amiodarone and transthoracic cardioversion were attempted in one llama with lone AF, but were unsuccessful. Atrial fibrillation was recorded in 0.1% of admissions. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  1. Atrial fibrillation pearls and perils of management.

    Science.gov (United States)

    Kudenchuk, P J

    1996-01-01

    Atrial fibrillation, a common arrhythmia, is responsible for considerable cardiovascular morbidity. Its management demands more than antiarrhythmic therapy alone, but must address the causes and consequences of the arrhythmia. Although remediable causes are infrequently found, a thorough search for associated heart disease or its risk factors results in better-informed patient management. Controlling the ventricular response and protecting from thromboembolic complications are important initial goals of therapy and may include the administration of aspirin in younger, low-risk patients. Older patients and those with risk factors for systemic embolism are not adequately protected from stroke complications by aspirin therapy alone. It remains controversial whether all high-risk patients should receive warfarin and at what intensity. Whether and how sinus rhythm should be restored and maintained poses the greatest therapeutic controversy for atrial fibrillation. The mortal risk of antiarrhythmic therapy is substantially greater in patients with evidence of heart failure. In such persons, the risks and benefits of maintaining normal sinus rhythm with antiarrhythmic medications should be weighted carefully. A definitive cure for atrial fibrillation remains elusive, but promising surgical and catheter ablation therapies are being developed. PMID:8686300

  2. 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.

  3. Human cardiomyocyte progenitor cell transplantation preserves long-term function of the infarcted mouse myocardium

    NARCIS (Netherlands)

    Smits, Anke M.; van Laake, Linda W.; den Ouden, Krista; Schreurs, Chantal; Szuhai, Karoly; van Echteld, Cees J.; Mummery, Christine L.; Doevendans, Pieter A.; Goumans, Marie-Jose

    2009-01-01

    Recent clinical studies revealed that positive results of cell transplantation on cardiac function are limited to the short- and mid-term restoration phase following myocardial infarction (MI), emphasizing the need for long-term follow-up. These transient effects may depend on the transplanted

  4. Recurrence of pulmonary vein conduction and atrial fibrillation after pulmonary vein isolation for atrial fibrillation

    DEFF Research Database (Denmark)

    Nilsson, Brian; Chen, Xu; Pehrson, Steen

    2006-01-01

    BACKGROUND: Both segmental ostial and circumferential extraostial pulmonary vein (PV) isolation have been proven effective in the treatment of atrial fibrillation (AF). However, the recurrence of AF and PV conduction after the 2 ablation strategies has never been compared in a randomized study...... isolation. Extraostial PV isolation was performed by encircling the paired left and right PVs, respectively, guided by an electroanatomic mapping system. RESULTS: A total of 84% of the patients had recurrent AF after the first PV isolation procedure, showing 72% with AF and 12% with organized left atrial...

  5. Interaction of metabolic and respiratory acidosis with α and β-adrenoceptor stimulation in rat myocardium.

    Science.gov (United States)

    Biais, Matthieu; Jouffroy, Romain; Carillion, Aude; Feldman, Sarah; Jobart-Malfait, Aude; Riou, Bruno; Amour, Julien

    2012-12-01

    The effects of acute respiratory versus metabolic acidosis on the myocardium and their consequences on adrenoceptor stimulation remain poorly described. We compared the effects of metabolic and respiratory acidosis on inotropy and lusitropy in rat myocardium and their effects on the responses to α- and β-adrenoceptor stimulations. The effects of acute respiratory and metabolic acidosis (pH 7.10) and their interactions with α and β-adrenoceptor stimulations were studied in isolated rat left ventricular papillary muscle (n=8 per group). Intracellular pH was measured using confocal microscopy and a pH-sensitive fluorophore in isolated rat cardiomyocytes. Data are mean percentages of baseline±SD. Respiratory acidosis induced more pronounced negative inotropic effects than metabolic acidosis did both in isotonic (45±3 versus 63±6%, Prespiratory or metabolic acidosis. The inotropic response to β-adrenergic stimulation was impaired only in metabolic acidosis (137±12 versus 200±33%, Pacidosis. The lusitropic response to β-adrenergic stimulation was not modified by respiratory or metabolic acidosis. Acute metabolic and respiratory acidosis induce different myocardial effects related to different decreases in intracellular pH. Only metabolic acidosis impairs the positive inotropic effect of β-adrenergic stimulation.

  6. Metabolic borderzone in acutely ischemic canine myocardium demonstrated by positron-CT (PCT)

    International Nuclear Information System (INIS)

    Schwaiger, M.; Hansen, H.; Selin, C.; Wittmer, S.; Barrio, J.; Schelbert, H.R.

    1984-01-01

    Acute coronary ligation in dogs results in an area of myocardial dysfunction that exceeds the area of subsequent necrosis suggesting the existence of an ischemic ''borderzone'' of reversibly injured myocardium. The authors tested this hypothesis in 9 closed chest dogs with C-11 plamitate (CPA) and serial PCT imaging after an LAD occlusion. Using a blood flow (MBF) image obtained with iv N-13 ammonia prior to CPA, regions of interest were assigned on the serial CPA cross-sectional images to the center (IC) and border (IB) of the ischemic segment and to control myocardium (CO). CPA uptake was closely related to MBF (r=0.88) implicating flow as a major determinant of CPA uptake. Clearance helftimes (T 1/2) and relative sizes (RS) of the early rapid phase on the C-11 tissue time activity curves were determined for IC, IB and CO. In IC, MBF, RS and T 1/2 were markedly depressed indicating impaired CPA utilization and oxidation. In IB, MBF was less than in CO though only insignificantly, while RS and T 1/2 were highly abnormal. The authors conclude that FFA metabolism in areas adjacent to ischemic segments but without significant MBF decreases in abnormal, presenting evidence for a metabolic borderzone which now can be identified noninvasively with positron emission tomography

  7. Study on the kinetics of high-energy phosphates in myocardium by phosphorous nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Kusuoka, Hideo; Tsuneoka, Yutaka; Inoue, Michitoshi; Abe, Hiroshi [Osaka Univ. (Japan). Faculty of Medicine; Watari, Hiroshi

    1982-12-01

    Effect of artificial blood, FC 43 (Perfluorochemicals) on the kinetics of high-energy phosphate in the myocardium was evaluated by /sup 31/P-NMR which permits a continuous and non-invasive assessment of in vivo phosphorus compounds. Cardiac perfusion was carried out on a excised rat heart with a Krebs-Henseleit modified solution and FC 43 alternately. Under the normal condition, ischemic condition, and at second perfusion amounts of intramyocardial creatine phosphoric acid, ATP, and inorganic phosphorus were determined by /sup 31/P-NMR. Coronary flow was simultaneously estimated. The ischemic state due to interruption of perfusion resulted in a decrease in creatine phosphoric acid, which was associated with an increase in inorganic phosphorus and intracellular acidosis. No change of ATP amount was observed under ischemic state. With resumption of perfusion, the levels of creatine phosphoric acid and inorganic phosphorus rapidly returned to the normal. In the group of FC 43, coronary flow was 2.68 ml/min/g of the heart weight, about 1/2 of that of the Krebs-Henseleit group (5.68 ml/min/g of the heart weight). In controls, there was no difference between the two groups concerning creatine phosphoric acid level and recovery of creatine phospohric acid level after ischemia. These results showed that FC 43 supplies sufficient oxygen, and has no effect on the kinetics of energy in the myocardium.

  8. Experimental basis of metabolic imaging of the myocardium with radioiodinated aromatic free fatty acids

    International Nuclear Information System (INIS)

    Reske, S.N.; Knapp, F.F. Jr.; Winkler, C.

    1986-01-01

    For the investigation of myocardial perfusion and left ventricular pump function, advanced radioisotopic techniques have been established. New developments in radiopharmacology and single-photon emission computed tomography have recently enabled the investigation of parameters of regional energy metabolism in well defined areas of the heart muscle. For this purpose, various iodine ( 123 I)-labeled free fatty acids (FFA) have been synthesized. The diagnostic application of labeled FFA in heart disease may be important, since FFA are the preferred substrates for cardiac energy production at rest in the fasting state. In addition, regional myocardial FFA uptake and regional myocardial blood flow are tightly coupled in normal myocardium with beta-oxidation which is extremely sensitive to oxygen deprivation. This article outlines the basic physiologic pathways of FFA in normal and ischemic myocardium and reviews the results of animal experiments validating the application of these principles for metabolic imaging of the heart by means of the aromatic radioiodinated FFA, 15-(p-iodophenyl)pentadecanoic acid. In addition, the development, physiologic properties, and potential applications of a new generation of 3-methyl-substituted radioiodinated fatty acids that show high myocardial uptake but prolonged retention are discussed. 64 references

  9. Segmenting high-frequency intracardiac ultrasound images of myocardium into infarcted, ischemic, and normal regions.

    Science.gov (United States)

    Hao, X; Bruce, C J; Pislaru, C; Greenleaf, J F

    2001-12-01

    Segmenting abnormal from normal myocardium using high-frequency intracardiac echocardiography (ICE) images presents new challenges for image processing. Gray-level intensity and texture features of ICE images of myocardium with the same structural/perfusion properties differ. This significant limitation conflicts with the fundamental assumption on which existing segmentation techniques are based. This paper describes a new seeded region growing method to overcome the limitations of the existing segmentation techniques. Three criteria are used for region growing control: 1) Each pixel is merged into the globally closest region in the multifeature space. 2) "Geographic similarity" is introduced to overcome the problem that myocardial tissue, despite having the same property (i.e., perfusion status), may be segmented into several different regions using existing segmentation methods. 3) "Equal opportunity competence" criterion is employed making results independent of processing order. This novel segmentation method is applied to in vivo intracardiac ultrasound images using pathology as the reference method for the ground truth. The corresponding results demonstrate that this method is reliable and effective.

  10. Effects of allocryptopine on outward potassium current and slow delayed rectifier potassium current in rabbit myocardium.

    Science.gov (United States)

    Fu, Yi-Cheng; Zhang, Yu; Tian, Liu-Yang; Li, Nan; Chen, Xi; Cai, Zhong-Qi; Zhu, Chao; Li, Yang

    2016-05-01

    Allocryptopine (ALL) is an effective alkaloid of Corydalis decumbens (Thunb.) Pers. Papaveraceae and has proved to be anti-arrhythmic. The purpose of our study is to investigate the effects of ALL on transmural repolarizing ionic ingredients of outward potassium current (I to) and slow delayed rectifier potassium current (I Ks). The monophasic action potential (MAP) technique was used to record the MAP duration of the epicardium (Epi), myocardium (M) and endocardium (Endo) of the rabbit heart and the whole cell patch clamp was used to record I to and I Ks in cardiomyocytes of Epi, M and Endo layers that were isolated from rabbit ventricles. The effects of ALL on MAP of Epi, M and Endo layers were disequilibrium. ALL could effectively reduce the transmural dispersion of repolarization (TDR) in rabbit transmural ventricular wall. ALL decreased the current densities of I to and I Ks in a voltage and concentration dependent way and narrowed the repolarizing differences among three layers. The analysis of gating kinetics showed ALL accelerated the channel activation of I to in M layers and partly inhibit the channel openings of I to in Epi, M and Endo cells. On the other hand, ALL mainly slowed channel deactivation of I Ks channel in Epi and Endo layers without affecting its activation. Our study gives partially explanation about the mechanisms of transmural inhibition of I to and I Ks channels by ALL in rabbit myocardium. These findings provide novel perspective regarding the anti-arrhythmogenesis application of ALL in clinical settings.

  11. Biophysical foundations for the study of the electrical excitability and action potential propagation in myocardium

    International Nuclear Information System (INIS)

    Suarez Antola, R.

    1991-01-01

    The electric current flow in the heterogeneous and anysotropic volume conductor of the myocardium is studied. The equations of bidomain theory are derived using an approach framed in the theory of averaged fields, introducing microscopic, mesoscopic and macroscopic spatial scales. However, the procedure, compatible with the histological and the anatomical details of the organ, is different from the multiple scale asymptotic expansions usually applied in homogeneization problems. A probabilistic approach framed in large numbers theorems is used to derive the equation for membrane ionic current from the stochastic activity of the channels at the microscopic level. An operational procedure suitable to define a sharp bidomain boundary from the fuzzy distribution of structural details and physical properties at the histological level is given. The problem of threshold is studied. The sizes and shapes of critical masses of cardiac cells that must be depolarized above threshold in order to produce a propagated action potential are determined by an approximate analytical procedure. The concept of family of threshold patterns for the emergence of action potentials in the heart is introduced. This concept is applied to discuss the conditions of emergence of ectopic focus. Analytical formulae are derived, for the time constant and the rheobase for electrical stimulation of the myocardium. These formulae are in good agreement with known experimental results. New experiments that could be done to confirm or reject them are suggested

  12. Intrinsic washout rates of thallium-201 in normal and ischemic myocardium after dipyridamole-induced vasodilation

    International Nuclear Information System (INIS)

    Beller, G.A.; Holzgrefe, H.H.; Watson, D.D.

    1985-01-01

    Infusion of dipyridamole has been suggested as an alternative to exercise stress for myocardial perfusion imaging for detection of ischemia, but the mechanism and significance of thallium-201 ( 201 Tl) redistribution after administration of dipyridamole are uncertain. If disparate intrinsic cellular efflux rates of 201 Tl from normal and relatively underperfused myocardium in response to dipyridamole-induced vasodilation were observed, this could explain delayed 201 Tl redistribution. We investigated the effect of an intravenous infusion of 0.15 mg/kg dipyridamole on the intrinsic myocardial washout rate of 201 Tl as measured with a gamma-detector probe after intracoronary injection (50 muCi) of the radionuclide in open-chested anesthetized dogs. In six normal dogs the t 1/2 for intrinsic 201 Tl washout from the myocardium was 89 +/- 11 min (SE) at control conditions and became more rapid at 59 +/- 10 min (p . .0001) after dipyridamole. This corresponded to a significant increase in microsphere-determined epicardial (0.95 +/- 0.11 to 2.23 +/- 0.46 ml/min/g; p . .01) and endocardial (0.86 +/- 0.10 to 1.53 +/- 0.27; p . .029) flows. In 12 dogs with a critical coronary stenosis, the 201 Tl intrinsic washout rate slowed from 70 +/- 5 to 104 +/- 6 min (p . .0001) after production of the stenosis and slowed even further to 169 +/- 21 min (p . .003) after dipyridamole

  13. Oxygen supply and oxidative phosphorylation limitation in rat myocardium in situ.

    Science.gov (United States)

    Kreutzer, U; Mekhamer, Y; Chung, Y; Jue, T

    2001-05-01

    The 1H-NMR signal of the proximal histidyl-N(delta)H of deoxymyoglobin is detectable in the in situ rat myocardium and can reflect the intracellular PO2. Under basal normoxic conditions, the cellular PO2 is sufficient to saturate myoglobin (Mb). No proximal histidyl signal of Mb is detectable. On ligation of the left anterior descending coronary artery, the Mb signal at 78 parts/million (ppm) appears, along with a peak shoulder assigned to the corresponding signal of Hb. During dopamine infusion up to 80 microg. kg(-1) x min(-1), both the heart rate-pressure product (RPP) and myocardial oxygen consumption (MVO2) increase by about a factor of 2. Coronary flow increases by 84%, and O2 extraction (arteriovenous O2 difference) rises by 31%. Despite the increased respiration and work, no deoxymyoglobin signal is detected, implying that the intracellular O2 level still saturates MbO2, well above the PO2 at 50% saturation of Mb. The phosphocreatine (PCr) level decreases, however, during dopamine stimulation, and the ratio of the change in P(i) over PCr (DeltaP(i)/PCr) increases by 0.19. Infusion of either pyruvate, as the primary substrate, or dichloroacetate, a pyruvate dehydrogenase activator, abolishes the change in DeltaP(i)/PCr. Intracellular O2 supply does not limit MVO2, and the role of ADP in regulating respiration in rat myocardium in vivo remains an open question.

  14. Focalized contractile impairment at hypertrophied myocardium proven in consideration of wall stress in patients with hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    Yamazaki, Tadashi; Suzuki, Jun-ichi; Shimamoto, Ryoichi; Tsuji, Taeko; Ohmoto, Yuki; Toyo-oka, Teruhiko; Omata, Masao; Ohtomo, Kuni; Nagai, Ryozo

    2006-01-01

    In hypertrophic cardiomyopathy (HCM) a hyperkinetic state is sometimes observed in spite of impaired systolic function in the hypertrophied myocardium. The aim of the present study was to determine the mechanism of this paradox. Seventeen patients with HCM and 10 normal subjects underwent cine magnetic resonance (MR) imaging to measure percent systolic wall thickening and percent fractional shortening. The ratio of systolic radial wall stress of the LV at the hypertrophied myocardium over that at the nonhypertrophied myocardium was evaluated to describe the focal advantageous condition for wall thickening. The ratio was 0.66±0.36 at the start of contraction and 0.78±0.31 at early-systole, indicating consistently smaller radial wall stress at the hypertrophied myocardium. Although the condition for contraction was favorable (a ratio less than 1.00), percent systolic wall thickening at the hypertrophied myocardium (23.0±11.8%) was smaller than that at the nonhypertrophied myocardium (70.5±32.3%). Smaller end-diastolic dimension (HCM group; 45.2±4.2 mm, reference group; 48.9±4.1 mm, P=0.04) with a statistically identical value of systolic decrease in intraventricular dimension (HCM group; 19.7±3.9 mm, reference group; 18.9±3.2 mm, P=0.60) yielded high percent fractional shortening in patients with HCM (43.5±7.6%). Although contractile impairment was proven at the hypertrophied region with low radial wall stress in the HCM group, the smaller end-diastolic dimension in this group resulted in high percent fractional shortening. (author)

  15. Histopathologic analysis of atrial tissue in patients with atrial fibrillation: comparison between patients with atrial septal defect and patients with mitral valvular heart disease.

    Science.gov (United States)

    Kwak, Jae Gun; Seo, Jeong-Wook; Oh, Sam Se; Lee, Sang Yun; Ham, Eui Keun; Kim, Woong-Han; Kim, Soo-Jin; Bae, Eun Jung; Lim, Cheoung; Lee, Chang-Ha; Lee, Cheul

    2014-01-01

    Atrial fibrillation (AF) in adult patients with atrial septal defect (ASD) accompanies an enlarged right atrium (RA) with a less enlarged left atrium (LA), which is the opposite situation in patients with AF and mitral valvular disease. This study was to compare the histopathological change in the atrium of patients with AF of two different etiologies: ASD and mitral disease. Twenty-four patients were enrolled. Group 1 included patients with ASD (8), Group 2 included patients with ASD with AF (6), and Group 3 included patients with mitral disease with AF (10). Preoperative atrial volumes were measured. Atrial tissues were obtained during surgical procedures and stained with periodic acid-Schiff, smooth muscle actin, Sirius red, and Masson's trichrome to detect histopathologic changes compatible with AF. The severity of histopathological changes was represented with "positivity" and "strong positivity" after analyzing digitalized images of the staining. We investigated the relationship between the degree of atrial dilatation and severity of histopathological changes according to the groups and tissues. Group 2 and Group 3 patients showed a tendency toward an enlarged RA volume and enlarged LA volume, respectively, compared with each others. However, in the histopathologic analysis, "positivity" and "strong positivity" showed no significant positive correlations with the degree of atrial volume in special staining. A similar degree of histopathologic changes was observed in both atria in patients with AF (Group 2 and 3) regardless of the degree of dilatation of atrial volume and disease entities. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

  16. Manifestation of automaticity in the pulmonary-vein myocardium of rats with abdominal aorto-venocaval shunt

    Directory of Open Access Journals (Sweden)

    Shogo Hamaguchi

    2015-08-01

    Full Text Available Effect of abdominal aorto-venocaval shunt (AVS on the automaticity of the pulmonary-vein myocardium was studied in the rat. Spontaneous electrical activity was observed in one third of the isolated pulmonary-vein preparations from the AVS rats, but scarcely in those from sham-operated rats; the activity was induced by tertiapin and suppressed by carbachol or chelation of intracellular Ca2+. The evoked action potentials in AVS rats had less negative resting membrane potential and longer action potential duration than those in sham-operated rats. These results suggest that the automaticity of the rat pulmonary-vein myocardium is manifested under chronic volume overload.

  17. Delayed uptake and washout of contrast in non-viable infarcted myocardium shown with dynamic computed tomography

    DEFF Research Database (Denmark)

    Udholm, Sebastian; Laugesen, Sofie; Agger, Peter

    2014-01-01

    BACKGROUND: Assessment of ischemic but potentially viable myocardium plays an important role in the planning of coronary revascularization. Until now SPECT, PET, and MRI have been used to identify viable myocardium. Computed tomography (CT) is increasingly used to diagnose coronary atherosclerosis...... descending artery, followed by removal of the balloon and reperfusion. Four pigs died due to refractory ventricular fibrillation. After 6 weeks, dynamic cardiac CT was performed assessing both wall motion and contrast attenuation. Measurements of attenuation values in Hounsfield units (HU) in the infarct...

  18. Arteriosclerotic changes in the myocardium, lung, and kidney in dogs with chronic congestive heart failure and myxomatous mitral valve disease

    DEFF Research Database (Denmark)

    Falk, Bo Torkel; Jönsson, Lennart; Olsen, Lisbeth Høier

    2006-01-01

    Background: The occurrence of small vessel arteriosclerosis in the myocardium, kidney, and lung in dogs with naturally occurring myxomatous mitral valve disease has not been previously investigated systematically. Methods: Twenty-one dogs with naturally occurring congestive heart failure and 21 age......-matched, sex-matched, and weight-matched control dogs underwent extensive pathological and histopathological examination. Morphometry and scoring of tissue sections were used to measure arterial narrowing and fibrosis in the myocardium, kidney, and lung; and intimal thickness and plaque formation in the aorta...... and pulmonary artery. Results: Dogs with congestive heart failure had significantly more arterial narrowing in the left ventricle (Pdogs. However...

  19. 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; Hancox, Jules C.; Aslanidi, Oleg V.

    2016-01-01

    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

  20. Atrial Fibrillation in Embolic Stroke: Anticoagulant Therapy at UNTH ...

    African Journals Online (AJOL)

    Objective: The decision to commence anticoagulation in a patient with embolic stroke and atrial fibrillation (AF) is often a difficult one for many clinicians. The result can have significant impact on the patient. This study was therefore undertaken to review the use of anticoagulation in embolic stroke in the setting of atrial ...

  1. 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....

  2. The safety of flecainide treatment of atrial fibrillation

    DEFF Research Database (Denmark)

    Almroth, H; Andersson, Torben Bech; Fengsrud, E

    2011-01-01

    To assess the safety of long-term treatment with flecainide in patients with atrial fibrillation (AF), particularly with regard to sudden cardiac death (SCD) and proarrhythmic events.......To assess the safety of long-term treatment with flecainide in patients with atrial fibrillation (AF), particularly with regard to sudden cardiac death (SCD) and proarrhythmic events....

  3. Dabigatran versus warfarin in patients with atrial fibrillation

    NARCIS (Netherlands)

    Connolly, Stuart J.; Ezekowitz, Michael D.; Yusuf, Salim; Eikelboom, John; Oldgren, Jonas; Parekh, Amit; Pogue, Janice; Reilly, Paul A.; Themeles, Ellison; Varrone, Jeanne; Wang, Susan; Alings, Marco; Xavier, Denis; Zhu, Jun; Diaz, Rafael; Lewis, Basil S.; Darius, Harald; Diener, Hans-Christoph; Joyner, Campbell D.; Wallentin, Lars; Connolly, S. J.; Ezekowitz, M. D.; Yusuf, S.; Eikelboom, J.; Oldgren, J.; Parekh, A.; Reilly, P. A.; Themeles, E.; Varrone, J.; Wang, S.; Palmcrantz-Graf, E.; Haehl, M.; Wallentin, L.; Alings, A. M. W.; Amerena, J. V.; Avezum, A.; Baumgartner, I.; Brugada, J.; Budaj, A.; Caicedo, V.; Ceremuzynski, L.; Chen, J. H.; Commerford, P. J.; Dans, A. L.; Darius, H.; Di Pasquale, G.; Diaz, R.; Erol, C.; Ferreira, J.; Flaker, G. C.; Flather, M. D.; Franzosi, M. G.; Gamboa, R.; Golitsyn, S. P.; Gonzalez Hermosillo, J. A.; Halon, D.; Heidbuchel, H.; Hohnloser, S. H.; Hori, M.; Huber, K.; Jansky, P.; Kamensky, G.; Keltai, M.; Kim, S.; Lau, C. P.; Le Heuzey, J. Y. F.; Lewis, B. S.; Liu, L. S.; Nanas, J.; Razali, O.; Pais, P. S.; Parkhomenko, A. N.; Pedersen, K. E.; Piegas, L. S.; Raev, D.; Simmers, T. A.; Smith, P. J.; Talajic, M.; Tan, R. S.; Tanomsup, S.; Toivonen, L.; Vinereanu, D.; Xavier, D.; Zhu, J.; Diener, H. C.; Joyner, C. D.; Diehl, A.; Ford, G.; Robinson, M.; Silva, J.; Sleight, P.; Wyse, D. G.; Collier, J.; de Mets, D.; Hirsh, J.; Lesaffre, E.; Ryden, L.; Sandercock, P.; Anastasiou-Nana, M. I.; Andersen, G.; Annex, B. H.; Atra, M.; Bornstein, N. M.; Boysen, G.; Brouwers, P. J. A. M.; Buerke, M.; Burrell, L. M.; Chan, Y. K.; Chen, W. H.; Cheung, R. T. F.; Divakaramenon, S.; Donnan, G. A.; Duray, G. Z.; Dvorakova, H.; Fiedler, J.; Gardinale, E.; Gates, P. C.; Goshev, E. G.; Goto, S.; Gross, B.; Guimaraes, H. P.; Gulkevych, O.; Haberl, R. L.; Hankey, G.; Hartikainen, J.; Healey, J.; Iliesiu, A. M.; Irkin, O.; Jaxa-Chamiec, T.; Jolly, S.; Kaste, K. A. M.; Kies, B.; Kostov, K. D.; Kristensen, K. S.; Labovitz, A. J.; Lassila, R. P. T.; Lee, K. L. F.; Lutay, Y. M.; Magloire, P.; Mak, K. H.; Meijer, A.; Mihov, L.; Morillo, C. A.; Morillo, L. E.; Nair, G. M.; Norrving, B.; Ntalianis, A.; Ntsekhe, M.; Olah, L.; Pasco, P. M. D.; Peeters, A.; Perovic, V.; Petrov, I.; Pizzolato, G.; Rafti, F.; Rey, N. R.; Ribas, S.; Rokoss, M.; Sarembock, I. J.; Sheth, T.; Shuaib, A.; Sitkei, E.; Sorokin, E.; Srámek, M.; Strozynska, E.; Tanne, D.; Thijs, V. N. S.; Tomek, A.; Turazza, F.; Vanhooren, G.; Vizel, S. A.; Vos, J.; Wahlgren, N.; Weachter, R.; Zaborska, B.; Zaborski, J.; Zimlichman, R.; Cong, J.; Fendt, K.; Muldoon, S.; Bajkor, S.; Grinvalds, A.; Malvaso, M.; Pogue, J.; Simek, K.; Yang, S.; Alzogaray, M. F.; Bono, J. O.; Caccavo, A.; Cartasegna, L.; Casali, W. P.; Cuello, J. L.; Cuneo, C. A.; Elizari, M. V.; Fernandez, A. A.; Ferrari, A. E.; Gabito, A. J.; Goicoechea, R. F.; Gorosito, V. M.; Hirschson, A.; Hominal, M. A.; Hrabar, A. D.; Liberman, A.; Mackinnon, I. J.; Manzano, R. D.; Muratore, C. A.; Nemi, S. A.; Rodriguez, M. A.; Sanchez, A. S.; Secchi, J.; Vogel, D. R.; Colquhoun, D. M.; Crimmins, D. S.; Dart, A. M.; Davis, S. M.; Hand, P. J.; Kubler, P. A.; Lehman, R. G.; McBain, G.; Morrison, H. C.; New, G.; Singh, B. B.; Spence, C. Z.; Waites, J. H.; Auer, J.; Doweik, L.; Freihoff, F.; Gaul, G.; Gazo, F.; Geiger, H.; Giacomini, G.; Huber, G. W.; Jukic, I.; Lamm, G.; Niessner, H.; Podczeck, A.; Schuh, J.; Siostrzonek, P.; Steger, C.; Vogel, B.; Watzak, R.; Weber, H. S.; Weihs, W.; Blankoff, I.; Boland, J. L.; Brike, C.; Carlier, M.; Cools, F.; de Meester, A.; de Raedt, H. J.; de Wolf, L.; Dhooghe, G. M.; Dilling-Boer, D.; Elshot, S. R.; Fasseaux, S.; Goethals, M.; Goethals, P.; Gurne, O.; Hellemans, S.; Ivan, B.; Jottrand, M.; Kersschot, I.; Lecoq, E.; Marcovitch, O.; Melon, D.; Miljoen, H.; Missault, L.; Pierard, L. A.; Provenier, F.; Rousseau, M. F.; Stockman, D.; Tran-Ngoc, E.; van Mieghem, W.; Vandekerckhove, Y.; Vandervoort, P.; Verrostte, J.; Vijgen, J.; Armaganijan, D.; Braga, C.; Braga, J. C. F.; Cipullo, R.; Cunha, C. L. P.; de Paola, A.; Delmonaco, M. I.; Guimaraes, F. V.; Herek, L.; Kerr Saraiva, J. F.; Maia, L. N.; Lorga, A. M.; Lorga-Filho, A. M.; Marino, R. L.; Melo, C. S.; Mouco, O. M.; Pereira, V. C.; Precoma, D. B.; Rabelo, W.; Rassi, S.; Rossi, P. R.; Rossi Neto, J. M.; Silva, F. M.; Vidotti, M. H.; Zimmermann, S. L.; Anev, E. D.; Balabanov, T. A.; Baldjiev, E. S.; Bogusheva, E. S.; Chaneva, M. A.; Filibev, I. G.; Gotcheva, N. N.; Goudev, A. R.; Gruev, I. T.; Guenova, D. T.; Kamenova, Z. A.; Manov, E. I.; Panov, I. A.; Parvanova, Z. I.; Pehlivanova, M. B.; Penchev, P. T.; Penkov, N. Y.; Radoslavov, A. L.; Ramshev, K. N.; Runev, N. M.; Sindzhielieva, M. N.; Spirova, D. A.; Tsanova, V. M.; Tzekova, M. L.; Yaramov, G. K.; Aggarwal, R.; Bakbak, A. I.; Bayly, K.; Berlingieri, J. C.; Blackburn, K.; Bobbie, C.; Booth, A. W.; Borts, D.; Bose, S.; Boucher, P.; Brown, K.; Burstein, J. M.; Butt, J. C.; Carlson, B. D.; Chetty, R.; Chiasson, J. D.; Constance, C.; Costi, P.; Coutu, B.; Deneufbourg, I.; Dion, D.; Dorian, P.; Douketis, J. D.; Farukh, S.; Filipchuk, N. G.; Fox, B. A.; Fox, H. I.; Gailey, C. B.; Gauthier, M.; Glanz, A.; Green, M. S.; Habot, J.; Hink, H.; Kearon, C.; Kouz, S.; Lai, C.; Lai, K.; Lalani, A. V.; Lam, A. S.; Lapointe, L. A.; Leather, R. A.; Ma, P. T. S.; MacKay, E.; Mangat, I.; Mansour, S.; Melton, E.; Mitchell, L. B.; Morris, A. L.; Nisker, W. A.; O'Donnell, M. J.; O'Hara, G.; Omichinski, L. M.; Pandey, A. S.; Parkash, R.; Pesant, Y.; Pilon, C.; Pistawka, K. J.; Powell, C. N.; Price, J. B.; Prieur, S.; Rebane, T. M.; Ricci, A. J.; Roberge, J.; Roy, M.; Sapp, J. L.; Savard, D.; Schulman, S.; Sehl, M. J.; Sestier, F.; Shandera, R.; Shu, D.; Sterns, L. D.; St-Hilaire, R.; Syan, G. S.; Talbot, P.; Teitelbaum, I.; Tytus, R. H.; Winkler, L.; Zadra, R.; Zidel, B. S.; Bai, X. J.; Gao, W.; Gao, X.; Guan, D. M.; He, Z. S.; Hua, Q.; Li, H.; Li, L.; Li, W. M.; Lu, G. P.; Lv, S.; Meng, K.; Niu, H. Y.; Qi, D. G.; Qi, S. Y.; Qian, F.; Sun, N. L.; Wang, H. Y.; Wang, N. F.; Yang, Y. M.; Zeng, H.; Zhang, F.; Zhang, F. R.; Zhang, L.; Bohorquez, R.; Rosas, J. F.; Saent, L.; Vacca, M.; Velasco, V. M.; Belohlavek, J.; Cernohous, M.; Choura, M.; Dedek, V.; Filipensky, B.; Hemzsky, L.; Karel, I.; Kopeckova, I.; Kovarova, K.; Labrova, R.; Madr, T.; Poklopova, Z.; Rucka, D.; Simon, J.; Skalicka, H.; Smidova, M.; Spinar, J.; Dodt, K. K.; Egstrup, K.; Friberg, J.; Haar, D.; Husted, S.; Jensen, G. V.; Joensen, A. M.; Klarlund, K. K.; Lind Rasmussen, S.; Melchior, T. M.; Olsen, M. E.; Poulsen, M. K.; Ralfkiaer, N.; Rasmussen, L. H.; Skagen, K.; Airaksinen, K. E.; Huikuri, H. V.; Hussi, E. J.; Kettunen, P.; Mänttäri, M.; Melin, J. H.; Mikkelsson, J.; Peuhkurinen, K.; Virtanen, V. K.; Ylitalo, A.; Agraou, B.; Boucher, L.; Bouvier, J. M.; Boye, A.; Boye, B.; Decoulx, E. 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W.; Meisner, J. S.; Melucci, M. B.; Mercando, A.; Merlino, J. D.; Meymandi, S. K.; Miele, M. B.; Miller, R. H.; Miller, S. H.; Minor, S. T.; Mitchell, M. R.; Modi, M.; Mody, F. V.; Moeller, C. L.; Moloney, J. F.; Moran, J. E.; Morcos, N. C.; Morgan, A.; Mukherjee, S. K.; Mullinax, K.; Murphy, A. L.; Mustin, A. J.; Myers, G. I.; Naccarelli, G. V.; Nadar, V. K.; Nallasivan, M.; Navas, J. P.; Niazi, I. K.; Nsah, E. N.; Nunamaker, J. L.; Ochalek, T. B.; O'dea, D. J.; Ogilvie, P. D.; Olliff, B.; Omalley, A. K.; O'Neill, P. G.; Onufer, J. R.; Orchard, R. C.; Orihuela, L. A.; Ortiz, E. C.; O'Sullivan, M. T.; Padanilam, B. J.; Pandey, P.; Patel, D. V.; Patel, R. J.; Patel, V. B.; Patlola, R. R.; Pennock, G. D.; Perlman, R.; Peters, P. H.; Petrillo, A. V.; Pezzella, S.; Phillips, D.; Pierre-Louis, J. R.; Pilcher, G.; Pillai, C.; Pollock, S. G.; Pond, M. S.; Porterfield, J. K.; Presant, L.; Pressler, J.; Pribble, A. H.; Promisloff, S. D.; Pudi, K. K.; Putnam, D. L.; Quartner, J.; Quinn, J. C.; Quinnell, C. M.; Raad, G. L.; Rasmussen, L. A.; Ray, C.; Reiffel, J. A.; Reynertson, S.; Richardson, J. W.; Riley, C. P.; Rippy, J. S.; Rittelmeyer, J. T.; Roberts, D. M.; Robertson, R.; Robinson, V. J. B.; Rocco, T. A.; Rosenbaum, D.; Roth, E. M.; Rottman, J. N.; Rough, R. R.; Rubenstein, J. J.; Sakkal, A. M.; Saleem, T.; Salerno, D. M.; Samendinger, M. L.; Sandeno, S.; Santilli, T. M.; Santucci, P.; Sattar, P.; Saxman, K. A.; Schaefer, S.; Schmidt, J.; Schneider, R. M.; Schocken, D. D.; Schrader, M. K.; Schramm, B. A.; Schultz, R. W.; Schussheim, A. E.; Schwarz, E. F.; Seamon, M. C.; Sestero, J. D.; Shah, M. P.; Shah, R.; Shalaby, A.; Shanes, J. G.; Sheftel, G. L.; Sheikh, K. H.; Shein, A. B.; Shemonsky, N. K.; Shepler, A.; Sheridan, E.; Shipwash, T. M.; Shopnick, R. I.; Short, W. G.; Shoukfeh, M. F.; Sibia, R. S.; Siler, T. M.; Silva, J. A.; Simons, G. R.; Simpson, A. G.; Simpson, H. R.; Simpson, V. J.; Singh, B. N.; Singh, N.; Singh, V. N.; Sitz, C. J.; Skatrud, L.; Sklar, J.; Slotwiner, D. J.; Smith, P. F.; Smith, P. N.; Smith, R. H.; Smith, J. E.; Sodowick, B. C.; Solomon, A. J.; Soltero, E. A.; Sonel, A. F.; Sperling, R.; Spiller, C.; Spink, B. Z.; Sprinkle, L. W.; Spyropoulos, A. C.; Stamos, T. D.; Steljes, A. D.; Stillabower, M. E.; Stover, T.; Strain, J. E.; Strickland, T. L.; Suresh, D. P.; Takata, T. S.; Taylor, J. S.; Taylor, M.; Teague, S. M.; Teixeia, J. M.; Telfer, E. A.; Terry, P. S.; Terry, R. W.; Thai, H. M.; Thalin, M.; Thomas, V. N.; Thompson, C. A.; Thompson, M. A.; Thornton, J. W.; Tidman, R. E.; Toler, B. S.; Traina, M. I.; Trippi, J. A.; Ujiiye, D. L.; Usedom, J. E.; van de Graaff, E.; van de Wall, L. R.; Vaughn, J. W.; Ver Steeg, D.; Vicari, R. M.; Vijay, N.; Vitale, C. B.; Vlastaris, A. G.; Voda, J.; Vora, K. N.; Voyles, W. F.; Vranian, R. B.; Vrooman, P. S.; Waack, P.; Waldo, A. L.; Walker, J. L.; Wallace, M. A.; Walsh, E. A.; Walsh, R. L.; Walton, A.; Washam, M.; Wehner, P. S.; Wei, J. Y.; Weiner, S.; Weiss, R. J.; Wells, D. M.; Wera-Archakul, W.; Wertheimer, J. H.; West, S. A.; Whitaker, J. H.; White, M. L.; White, R. H.; Whitehill, J. N.; Wiegman, P. J.; Wiesel, J.; Williams, J.; Williams, L. E.; Williams, M. L.; Williamson, V. K.; Wilson, V. E.; Wilson, W. W.; Woodfield, S. L.; Wulff, C. W.; Yates, S. W.; Yousuf, K. A.; Zakhary, B. G.; Zambrano, R.; Zimetbaum, P.; Zoble, R.; Zopo, A. R.; Zwerner, P. L.

    2009-01-01

    BACKGROUND: Warfarin reduces the risk of stroke in patients with atrial fibrillation but increases the risk of hemorrhage and is difficult to use. Dabigatran is a new oral direct thrombin inhibitor. METHODS: In this noninferiority trial, we randomly assigned 18,113 patients who had atrial

  4. EFFECT OF EXERCISE ON CYCLE LENGTH IN ATRIAL-FLUTTER

    NARCIS (Netherlands)

    VANDENBERG, MP; CRIJNS, HJGM; SZABO, BM; BROUWER, J; LIE, KI

    Objective-To examine the effect of exercise on cycle length in atrial flutter. Patients-15 patients with chronic atrial flutter. Seven patients were taking digoxin and six verapamil; two were not taking medication. Methods-All patients underwent bicycle ergometry. Flutter cycle length was measured

  5. 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

  6. Percutaneous left atrial appendage closure for stroke prevention

    DEFF Research Database (Denmark)

    De Backer, Ole; Loupis, Anastasia M; Ihlemann, Nikolaj

    2014-01-01

    INTRODUCTION: In atrial fibrillation (AF) patients with an increased stroke risk, oral anticoagulation (OAC) is the standard treatment for stroke prevention. However, this therapy carries a high risk of major bleeding. Percutaneous closure of the left atrial appendage (LAA) is suggested as an alt...

  7. Right atrial myxoma at Muhimbili National Hospital: a case report ...

    African Journals Online (AJOL)

    lower cava hypertension and was in NYHA class IV. The 2-D echocardiography revealed a right atrial tumor encroaching the tricuspid valve, chest radiography showed gross cardiomegally and right lower lung collapse. A clinical diagnosis of right atrial tumour was reached. The patient was scheduled to undergo open heart ...

  8. Saffold virus infection associated with human myocarditis

    DEFF Research Database (Denmark)

    Nielsen, Trine Skov; Nielsen, Alex Yde; Banner, Jytte

    2016-01-01

    BACKGROUND: Saffold virus was described in 2007 as one of the first human viruses within the genus cardioviruses. Cardioviruses may cause severe infections of the myocardium in animals, and several studies have associated saffold virus with human disease. As a result, saffold virus has been...... isolated from different anatomical compartments, including the myocardium, but, until now, it has not been possible to demonstrate the accompanying histopathological signs of inflammation. OBJECTIVES: The aim of the study was to examine if saffold virus is capable of causing invasive infection in the human...... myocardium. STUDY DESIGN: Using real-time PCR, we retrospectively examined formalin-fixed paraffin embedded cardiac tissue specimens from 150 deceased individuals diagnosed with myocarditis at autopsy. The results were compared with histological findings. RESULTS AND CONCLUSIONS: Saffold virus was detected...

  9. Pathophysiology and diagnosis of hibernating myocardium in patients with post-ischemic heart failure. The contribution of PET

    International Nuclear Information System (INIS)

    Camici, P.G.; Rimoldi, O.E.

    2003-01-01

    Identification and treatment of hibernating myocardium (HM) lead to improvement in left ventricular (LV) function and prognosis in patients with post-ischemic heart failure. Different techniques are used to diagnose HM: echocardiography, MRI, SPECT and PET and, in patients with moderate LV impairment, their predictive values are similar. There are few data on patients with severe LV dysfunction and heart failure in whom the greatest benefits are apparent after revascularization. Quantification of FDG uptake with PET during hyperinsulinemic euglycemic clamp is accurate in these patients with the greatest mortality risk in whom other techniques may give high false negative rates. The debate on whether resting myocardial blood flow to HM is reduced or not has stimulated new research on heart failure in patients with coronary artery disease. PET with H 2 15 O or 13 NH 3 has been used for the absolute quantification of regional blood flow in human HM. When HM is properly identified, resting blood flow is not different from that in healthy volunteers although a reduction of ∼20% can be demonstrated in a minority of cases. PET studies have shown that the main feature of HM is a severe impairment of coronary vasodilator reserve that improves after revascularization in parallel with LV function. Thus, the pathophysiology of HM is more complex than initially postulated. The recent evidence that repetitive ischemia in patients can be cumulative and lead to more severe and prolonged stunning, lends further support to the hypothesis that, at least initially, stunning and HM are two facets of the same coin. (author)

  10. Left Atrial Sphericity Index Predicts Early Recurrence of Atrial Fibrillation After Direct-Current Cardioversion

    DEFF Research Database (Denmark)

    Osmanagic, Armin; Möller, Sören; Osmanagic, Azra

    2016-01-01

    BACKGROUND: Attempts to achieve rhythm control using direct-current cardioversion (DCC) are common in those with persistent atrial fibrillation (AF). Although often successful, AF recurs within 1 month in as many as 57% of patients. The aim of this study was to assess whether a baseline left atri...

  11. 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

  12. Family history of atrial fibrillation is associated with earlier-onset and more symptomatic atrial fibrillation

    DEFF Research Database (Denmark)

    Gundlund, Anna; Fosbøl, Emil Loldrup; Kim, Sunghee

    2016-01-01

    BACKGROUND: We addressed whether patients with a family history of atrial fibrillation (AF) were diagnosed as having AF earlier in life, were more symptomatic, and had worse outcomes compared with those without a family history of AF. METHODS: Using the ORBIT-AF, we compared symptoms and disease...

  13. [Recurrent right atrial thrombus in a patient with atrial fibrillation and heart failure].

    Science.gov (United States)

    Elikowski, Waldemar; Wróblewski, Dariusz; Małek-Elikowska, Małgorzata; Mazurek, Andrzej; Foremska-Iciek, Joanna; Łazowski, Stanisław

    2015-11-01

    Atrial fibrillation and heart failure are factors predisposing to locally formed intracardiac thrombosis, which is usually localized in left-sided chambers. A case report. The authors present a case of a 50-year-old male with permanent atrial fibrillation and dilated cardiomyopathy in whom recurrent right atrial thrombus was observed. Initially, the lesion was detected in echocardiography while he was hospitalized due to extensive right-sided pneumonia. The thrombus was successfully treated with heparin, followed by warfarin. Even though the patient continued warfarin use properly, there was recurrence of the thrombus two years later during a new episode of heart failure exacerbation. Because the thrombus was resistant to intensified anticoagulation, cardiac surgery was needed. A large (30 x 25 mm) pedunculated thrombus, as well as two smaller ones (each of 10 x 10 mm) attached closely to the atrial wall and previously not detected either by echocardiography or by magnetic resonance imaging, were excited. A partially organized pattern of the thrombi in histological examination can explain lack of anticoagulation effectiveness. © 2015 MEDPRESS.

  14. Percutaneous left atrial appendage occlusion for stroke prevention in atrial fibrillation

    DEFF Research Database (Denmark)

    De Backer, O; Arnous, S; Ihlemann, N

    2014-01-01

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia encountered in clinical practice. One of its most devastating complications is the development of thromboembolism leading to fatal or disabling stroke. Oral anticoagulation (OAC, warfarin) is the standard treatment for strok...

  15. Atrial fibrillation and vascular disease-a bad combination

    DEFF Research Database (Denmark)

    Bjerring Olesen, Jonas; Gislason, Gunnar Hilmar; Torp-Pedersen, Christian

    2012-01-01

    This article provides an overview of (i) the risk of stroke associated with vascular disease (acute coronary syndromes and peripheral artery disease) in patients with atrial fibrillation, (ii) the frequent coexistence of vascular disease in patients with atrial fibrillation and, (iii...... fibrillation. Indeed, patients with atrial fibrillation often had coexisting vascular disease (around 18%), and the combination of the two diseases substantially increases the risk of future cardiovascular events. The increased risk associated with peripheral artery disease in atrial fibrillation is even more...... pronounced. Patients with atrial fibrillation and stable vascular disease should be treated with oral anticoagulation only, although when these patients present with acute coronary syndrome and/or undergo coronary stenting, concomitant treatment with antiplatelet drugs is indicated. To guide antithrombotic...

  16. Ventricular rhythm in atrial fibrillation under anaesthetic infusion with propofol

    International Nuclear Information System (INIS)

    Cervigón, R; Moreno, J; Pérez-Villacastín, J; Reilly, R B; Castells, F

    2009-01-01

    Changes in patients' autonomic tone and specific pharmacologic interventions may modify the ventricular response (actual heart rate) during atrial fibrillation (AF). Hypnotic agents such as propofol may modify autonomic balance as they promote a sedative state. It has been shown that propofol slightly slows atrial fibrillatory activity, but the net global effect on the ventricular response remains unknown. We aimed to evaluate in patients in AF the effect of a propofol bolus on the ventricular rate and regularity at ECG. We analysed the possible relation with local atrial fibrillatory activities, as ratios between atrial and ventricular rates (AVRs), analysing atrial activity from intracardiac electrograms at the free wall of the right and left atria and at the interatrial septum. We compared data at the baseline and after complete hypnosis. Propofol was associated with a more homogeneous ventricular response and lower AVR values at the interatrial septum

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. Atrial Fibrillation: When the heart is not in rhythm | NIH MedlinePlus the Magazine

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: When the heart is not in rhythm Past ... show, Deal With It . Photo: TBS/Deal Understanding Atrial Fibrillation Atrial fibrillation (AFib) is the most common type ...

  2. 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.

  3. Semi-automatic segmentation of myocardium at risk in T2-weighted cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Sjögren Jane

    2012-01-01

    Full Text Available Abstract Background T2-weighted cardiovascular magnetic resonance (CMR has been shown to be a promising technique for determination of ischemic myocardium, referred to as myocardium at risk (MaR, after an acute coronary event. Quantification of MaR in T2-weighted CMR has been proposed to be performed by manual delineation or the threshold methods of two standard deviations from remote (2SD, full width half maximum intensity (FWHM or Otsu. However, manual delineation is subjective and threshold methods have inherent limitations related to threshold definition and lack of a priori information about cardiac anatomy and physiology. Therefore, the aim of this study was to develop an automatic segmentation algorithm for quantification of MaR using anatomical a priori information. Methods Forty-seven patients with first-time acute ST-elevation myocardial infarction underwent T2-weighted CMR within 1 week after admission. Endocardial and epicardial borders of the left ventricle, as well as the hyper enhanced MaR regions were manually delineated by experienced observers and used as reference method. A new automatic segmentation algorithm, called Segment MaR, defines the MaR region as the continuous region most probable of being MaR, by estimating the intensities of normal myocardium and MaR with an expectation maximization algorithm and restricting the MaR region by an a priori model of the maximal extent for the user defined culprit artery. The segmentation by Segment MaR was compared against inter observer variability of manual delineation and the threshold methods of 2SD, FWHM and Otsu. Results MaR was 32.9 ± 10.9% of left ventricular mass (LVM when assessed by the reference observer and 31.0 ± 8.8% of LVM assessed by Segment MaR. The bias and correlation was, -1.9 ± 6.4% of LVM, R = 0.81 (p Conclusions There is a good agreement between automatic Segment MaR and manually assessed MaR in T2-weighted CMR. Thus, the proposed algorithm seems to be a

  4. Semi-automatic segmentation of myocardium at risk in T2-weighted cardiovascular magnetic resonance.

    Science.gov (United States)

    Sjögren, Jane; Ubachs, Joey F A; Engblom, Henrik; Carlsson, Marcus; Arheden, Håkan; Heiberg, Einar

    2012-01-31

    T2-weighted cardiovascular magnetic resonance (CMR) has been shown to be a promising technique for determination of ischemic myocardium, referred to as myocardium at risk (MaR), after an acute coronary event. Quantification of MaR in T2-weighted CMR has been proposed to be performed by manual delineation or the threshold methods of two standard deviations from remote (2SD), full width half maximum intensity (FWHM) or Otsu. However, manual delineation is subjective and threshold methods have inherent limitations related to threshold definition and lack of a priori information about cardiac anatomy and physiology. Therefore, the aim of this study was to develop an automatic segmentation algorithm for quantification of MaR using anatomical a priori information. Forty-seven patients with first-time acute ST-elevation myocardial infarction underwent T2-weighted CMR within 1 week after admission. Endocardial and epicardial borders of the left ventricle, as well as the hyper enhanced MaR regions were manually delineated by experienced observers and used as reference method. A new automatic segmentation algorithm, called Segment MaR, defines the MaR region as the continuous region most probable of being MaR, by estimating the intensities of normal myocardium and MaR with an expectation maximization algorithm and restricting the MaR region by an a priori model of the maximal extent for the user defined culprit artery. The segmentation by Segment MaR was compared against inter observer variability of manual delineation and the threshold methods of 2SD, FWHM and Otsu. MaR was 32.9 ± 10.9% of left ventricular mass (LVM) when assessed by the reference observer and 31.0 ± 8.8% of LVM assessed by Segment MaR. The bias and correlation was, -1.9 ± 6.4% of LVM, R = 0.81 (p Segment MaR, -2.3 ± 4.9%, R = 0.91 (p Segment MaR and manually assessed MaR in T2-weighted CMR. Thus, the proposed algorithm seems to be a promising, objective method for standardized MaR quantification in T2

  5. Stretch-dependent slow force response in isolated rabbit myocardium is Na+ dependent.

    Science.gov (United States)

    von Lewinski, Dirk; Stumme, Burkhard; Maier, Lars S; Luers, Claus; Bers, Donald M; Pieske, Burkert

    2003-03-15

    Stretch induces functional and trophic effects in mammalian myocardium via various signal transduction pathways. We tested stretch signal transduction on immediate and slow force response (SFR) in rabbit myocardium. Experiments were performed in isolated right ventricular muscles from adult rabbit hearts (37 degrees C, 1 Hz stimulation rate, bicarbonate-buffer). Muscles were rapidly stretched from 88% of optimal length (L88) to near optimal length (L98) for functional analysis. The resulting immediate and slow increases in twitch force (first phase and SFR, respectively) were assessed at reduced [Na+]o or without and with blockade of stretch activated ion channels (SACs), angiotensin-II (AT1) receptors, endothelin-A (ET(A)) receptors, Na+/H+-exchange (NHE1), reverse mode Na+/Ca2+-exchange (NCX), or Na+/K+-ATPase. The effects of stretch on sarcoplasmic reticulum Ca2+-load were characterized using rapid cooling contractures (RCCs). Intracellular pH was measured in BCECF-AM loaded muscles, and action potential duration (APD) was assessed using floating electrodes. On average, force increased to 216+/-8% of the pre-stretch value during the immediate phase, followed by a further increase to 273+/-10% during the SFR (n=81). RCCs significantly increased during SFR, whereas pH and APD did not change. Neither inhibition of SACs, AT1, or ET(A) receptors affected the stretch-dependent immediate phase nor SFR. In contrast, SFR was reduced by NHE inhibition and almost completely abolished by reduced [Na+]o or inhibition of reverse-mode NCX, whereas increased SFR was seen after raising [Na+]i by Na+/K+-ATPase inhibition. The data demonstrate the existence of a delayed, Na+- and Ca2+-dependent but pH and APD independent SFR to stretch in rabbit myocardium. This inotropic response appears to be independent of autocrine/paracrine AT1 or ET(A) receptor activation, but mediated through stretch-induced activation of NHE and reverse mode NCX.

  6. Pulmonary artery-to-left atrial fistula discovered after the closure of atrial septal defect: A rare clinical scenario

    Directory of Open Access Journals (Sweden)

    Akshay Chauhan

    2018-01-01

    Full Text Available A case of the right pulmonary artery-to- left atrial fistula with atrial septal defect (ASD is presented. The fistula was detected after the patient developed desaturation following surgical closure of the ASD. It was managed with a transcatheter (trans-RPA route closure of the fistula using a 12-mm Amplatzer ventricular septal defect closure device.

  7. Does Left Atrial Volume and Pulmonary Venous Anatomy Predict the Outcome of Catheter Ablation of Atrial Fibrillation ?

    NARCIS (Netherlands)

    Hof, Irene; Chilukuri, Karuna; Arbab-Zadeh, Armin; Scherr, Daniel; Dalal, Darshan; Nazarian, Saman; Henrikson, Charles; Spragg, David; Berger, Ronald; Marine, Joseph; Calkins, Hugh

    Introduction: Preprocedural factors may be helpful in selecting patients with atrial fibrillation (AF) for treatment with catheter ablation and in making an assumption regarding their prognosis. The aims of this study were to investigate whether left atrial (LA) volume and pulmonary venous (PV)

  8. Assessment of non-invasive time and frequency atrial fibrillation organization markers with unipolar atrial electrograms

    International Nuclear Information System (INIS)

    Alcaraz, Raúl; Hornero, Fernando; Rieta, José J

    2011-01-01

    The standard electrocardiogram (ECG) is the most common non-invasive way to study atrial fibrillation (AF). In this respect, previous works have shown that the surface lead V 1 reflects mainly the dominant atrial frequency (DAF) of the right atrium (RA), which has been widely used to study AF. In a similar way, AF organization and fibrillatory (f) wave amplitude are two recently proposed non-invasive AF markers. These markers need to be validated with invasive recordings in order to assess their capability to reliably reflect the internal fibrillatory activity dynamics. In this work, these two non-invasive metrics have been compared with similar measures recorded from two unipolar atrial electrograms (AEGs). For both ECG and AEG signals, AF organization has been computed by applying a nonlinear regularity index, such as sample entropy (SampEn), to the atrial activity (AA) and to its fundamental waveform, defined as the main atrial wave (MAW). The surface and epicardial f wave amplitude has been estimated through their mean power. Results obtained for 38 patients showed statistically significant correlations between the values measured from surface and invasive recordings, thus corroborating the usefulness of the aforesaid markers in the non-invasive study of AF. Precisely, for AF organization computed from the MAW, the correlation coefficients between surface and both AEGs were R = 0.926 (p < 0.001) and R = 0.932 (p < 0.001). For f wave amplitude, slightly lower significant relationships were noticed, the correlation coefficients being R = 0.765 (p < 0.001) and R = 0.842 (p < 0.001). These outcomes together with interesting linear relationships found among the parameters suggest that AF regularity estimated via SampEn and f wave amplitude can non-invasively characterize the epicardial activity related to AF

  9. Interatrial septum pacing decreases atrial dyssynchrony on strain rate imaging compared with right atrial appendage pacing.

    Science.gov (United States)

    Yasuoka, Yoshinori; Abe, Haruhiko; Umekawa, Seiko; Katsuki, Keiko; Tanaka, Norio; Araki, Ryo; Imanaka, Takahiro; Matsutera, Ryo; Morisawa, Daisuke; Kitada, Hirokazu; Hattori, Susumu; Noda, Yoshiki; Adachi, Hidenori; Sasaki, Tatsuya; Miyatake, Kunio

    2011-03-01

    Interatrial septum pacing (IAS-P) decreases atrial conduction delay compared with right atrial appendage pacing (RAA-P). We evaluate the atrial contraction with strain rate of tissue Doppler imaging (TDI) during sinus activation or with IAS-P or RAA-P. Fifty-two patients with permanent pacemaker for sinus node disease were enrolled in the study. Twenty-three subjects were with IAS-P and 29 with RAA-P. The time from end-diastole to peak end-diastolic strain rate was measured and corrected with RR interval on electrocardiogram. It was defined as the time from end-diastole to peak end-diastolic strain rate (TSRc), and the balance between maximum and minimum TSRc at three sites (ΔTSRc) was compared during sinus activation and with pacing rhythm in each group. There were no significant differences observed in general characteristics and standard echocardiographic parameters except the duration of pacing P wave between the two groups. The duration was significantly shorter in the IAS-P group compared with the RAA-P group (95 ± 34 vs 138 ± 41; P = 0.001). TSRc was significantly different between sinus activation and pacing rhythm (36.3 ± 35.7 vs 61.6 ± 36.3; P = 0.003) in the RAA-P group, whereas no significant differences were observed in the IAS-P group (25.4 ± 12.1 vs 27.7 ± 14.7; NS). During the follow-up (mean 2.4 ± 0.7 years), the incidence of paroxysmal atrial fibrillation (AF) conversion to permanent AF was not significantly different between the two groups. IAS-P decreased the contraction delay on atrial TDI compared to RAA-P; however, it did not contribute to the reduction of AF incidence in the present study. ©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.

  10. Atrial-selective K+ channel blockers: potential antiarrhythmic drugs in atrial fibrillation?

    Science.gov (United States)

    Ravens, Ursula

    2017-11-01

    In the wake of demographic change in Western countries, atrial fibrillation has reached an epidemiological scale, yet current strategies for drug treatment of the arrhythmia lack sufficient efficacy and safety. In search of novel medications, atrial-selective drugs that specifically target atrial over other cardiac functions have been developed. Here, I will address drugs acting on potassium (K + ) channels that are either predominantly expressed in atria or possess electrophysiological properties distinct in atria from ventricles. These channels include the ultra-rapidly activating, delayed outward-rectifying Kv1.5 channel conducting I Kur , the acetylcholine-activated inward-rectifying Kir3.1/Kir3.4 channel conducting I K,ACh , the Ca 2+ -activated K + channels of small conductance (SK) conducting I SK , and the two-pore domain K + (K2P) channels (tandem of P domains, weak inward-rectifying K + channels (TWIK-1), TWIK-related acid-sensitive K + channels (TASK-1 and TASK-3)) that are responsible for voltage-independent background currents I TWIK-1 , I TASK-1 , and I TASK-3 . Direct drug effects on these channels are described and their putative value in treatment of atrial fibrillation is discussed. Although many potential drug targets have emerged in the process of unravelling details of the pathophysiological mechanisms responsible for atrial fibrillation, we do not know whether novel antiarrhythmic drugs will be more successful when modulating many targets or a single specific one. The answer to this riddle can only be solved in a clinical context.

  11. [Left atrial electric isolation in the treatment of atrial fibrillation secondary to rheumatic valvular disease].

    Science.gov (United States)

    Graffigna, A; Pagani, F; Minzioni, G; Salerno, J; Viganò, M

    1992-08-01

    Surgical isolation of the left atrium was performed for the treatment of chronic atrial fibrillation secondary to valvular disease in 100 patients who underwent valve surgery. From May 1989 to September 1991, 62 patients underwent mitral valve surgery (Group I), 19 underwent mitral valve surgery and DeVega tricuspid annuloplasty (Group II), 15 underwent mitral and aortic surgery (Group III), and 4 patients underwent mitral and aortic surgery and DeVega tricuspid annuloplasty (Group IV). Left atrial isolation was performed prolonging the usual left paraseptal atriotomy towards the left fibrous trigone anteriorly, and the postero-medial commissure posteriorly. The incision was conducted a few millimeters apart from the mitral valve annulus, and cryolesion were placed at the edges to ensure complete electrophysiological isolation of the left atrium. Operative mortality accounted for 3 cases (3%). In 79 patients (81.4%) sinus rhythm recovered and persisted until discharge from the hospital. No differences were found between the groups (Group I: 80.7%; Group II: 68.5%; Group III 86.7%, Group IV 75% - p = N.S.). Three cases of late mortality (3.1%) were registered. long-term results showed persistence of SR in 71% of Group I, 61.2% of Group II, 85.8% of Group III, and 100% of Group IV. The unique risk factor for late recurrency of atrial fibrillation was found to be a duration of preoperative AF longer than 6 months. Due to the high success rate in recovering the sinus rhythm, we suggest left atrial isolation in patients with chronic atrial fibrillation undergoing valvular surgery.

  12. Combined percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation for rheumatic mitral stenosis and atrial fibrillation

    International Nuclear Information System (INIS)

    Murdoch, Dale; McAulay, Laura; Walters, Darren L.

    2014-01-01

    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

  13. 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.

  14. Nitrate administration increases blood flow in dysfunctional but viable myocardium, leading to improved assessment of myocardial viability : A PET study

    NARCIS (Netherlands)

    Slart, Riemer H. J. A.; Agool, Ali; van Veldhuisen, Dirk J.; Dierckx, Rudi A.; Bax, Jeroen J.

    SPECT with Tc-99m-labeled agents is better able to detect viability after nitrate administration. Nitrates induce vasoclilation and may increase blood flow to severely hypoperfused but viable myocardium, thereby enhancing tracer delivery and improving the detection of viability. Quantitative data on

  15. Collateral circulation as a marker of the presence of viable myocardium in patients with recent myocardial infarction

    International Nuclear Information System (INIS)

    Fujita, M.; Ohno, A.; Wada, O.; Miwa, K.; Nozawa, T.; Yamanishi, K.; Sasayama, S.

    1991-01-01

    The relationship between the presence of viable myocardium and the extent of coronary collateral circulation to the infarct area was evaluated in 20 patients with a recent anterior myocardial infarction who had complete obstruction of the left anterior descending coronary artery. The viability of myocardial tissue was assessed by exercise thallium-201 myocardial scintigraphy, and the collateral circulation was angiographically evaluated by means of a collateral index ranging from 0 to 3. Patients were divided into two groups according to the presence (group 1, n = 10) or absence (group 2, n = 10) of viable myocardium in the perfusion territory of the infarct-related artery. The collateral index in group 1 was 2.5 ± 0.5 (SD), which was significantly higher than the 0.7 ± 0.8 in group 2. These findings indicate that the presence of ischemic but viable myocardium is intimately related to the development of collateral circulation in patients with myocardial infarction, and the existence of well-developed collateral channels predicts the presence of viable myocardium in the infarct area

  16. Mitochondrial complex III defects contribute to inefficient respiration and ATP synthesis in the myocardium of Trypanosoma cruzi-infected mice.

    Science.gov (United States)

    Wen, Jian-Jun; Garg, Nisha Jain

    2010-01-01

    In this study, we conducted a thorough analysis of mitochondrial bioenergetic function as well as the biochemical and molecular factors that are deregulated and contribute to compromised adenosine triphosphate (ATP) production in the myocardium during Trypanosoma cruzi infection. We show that ADP-stimulated state 3 respiration and ATP synthesis supported by pyruvate/malate (provides electrons to complex I) and succinate (provides electrons to complex II) substrates were significantly decreased in left ventricular tissue and isolated cardiac mitochondria of infected mice. The decreased mitochondrial ATP synthesis in infected murine hearts was not a result of uncoupling between the electron-transport chain and oxidative phosphorylation and decreased availability of the intermediary metabolites (e.g., NADH). The observed decline in the activities of complex-I, -IV, and -V was not physiologically relevant and did not contribute to compromised respiration and ATP synthesis in infected myocardium. Instead, complex III activity was decreased above the threshold level and contributed to respiratory-chain inefficiency and the resulting decline in mitochondrial ATP synthesis in infected myocardium. The loss in complex III activity occurred as a consequence of cytochrome b depletion. Treatment of infected mice with phenyl-alpha-tert-butyl nitrone (PBN, antioxidant) was beneficial in preserving the mtDNA-encoded cytochrome b expression, and subsequently resulted in improved complex III activity, mitochondrial respiration, and ATP production in infected myocardium. Overall, we provide novel data on the mechanism(s) involved in cardiac bioenergetic inefficiency during T. cruzi infection.

  17. Capillary transfer constant of Gd-DTPA in the myocardium at rest and during vasodilation assessed by MRI

    DEFF Research Database (Denmark)

    Fritz-Hansen, T; Rostrup, Egill; Søndergaard, Lise

    1998-01-01

    The purpose of this study was to determine whether the capillary transfer constant (Ki) of gadolinium-DTPA was sensitive to perfusion changes and whether ischemic regions in the myocardium could be identified using the modified Kety formula. Ki was measured at rest and during dipyridamole...

  18. 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.

  19. 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.

  20. 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.

  1. Echocardiographic study of left atrial myxoma

    Directory of Open Access Journals (Sweden)

    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.

  2. Atrial overexpression of angiotensin-converting enzyme 2 improves the canine rapid atrial pacing-induced structural and electrical remodeling. Fan, ACE2 improves atrial substrate remodeling.

    Science.gov (United States)

    Fan, Jinqi; Zou, Lili; Cui, Kun; Woo, Kamsang; Du, Huaan; Chen, Shaojie; Ling, Zhiyu; Zhang, Quanjun; Zhang, Bo; Lan, Xianbin; Su, Li; Zrenner, Bernhard; Yin, Yuehui

    2015-01-01

    The purpose of this study was to investigate whether atrial overexpression of angiotensin-converting enzyme 2 (ACE2) by homogeneous transmural atrial gene transfer can reverse atrial remodeling and its mechanisms in a canine atrial-pacing model. Twenty-eight mongrel dogs were randomly divided into four groups: Sham-operated, AF-control, gene therapy with adenovirus-enhanced green fluorescent protein (Ad-EGFP) and gene therapy with Ad-ACE2 (Ad-ACE2) (n = 7 per subgroup). AF was induced in all dogs except the Sham-operated group by rapid atrial pacing at 450 beats/min for 2 weeks. Ad-EGFP and Ad-ACE2 group then received epicardial gene painting. Three weeks after gene transfer, all animals except the Sham group underwent rapid atrial pacing for another 3 weeks and then invasive electrophysiological, histological and molecular studies. The Ad-ACE2 group showed an increased ACE2 and Angiotensin-(1-7) expression, and decreased Angiotensin II expression in comparison with Ad-EGFP and AF-control group. ACE2 overexpression attenuated rapid atrial pacing-induced increase in activated extracellular signal-regulated kinases and mitogen-activated protein kinases (MAPKs) levels, and decrease in MAPK phosphatase 1(MKP-1) level, resulting in attenuation of atrial fibrosis collagen protein markers and transforming growth factor-β1. Additionally, ACE2 overexpression also modulated the tachypacing-induced up-regulation of connexin 40, down-regulation of connexin 43 and Kv4.2, and significantly decreased the inducibility and duration of AF. ACE2 overexpression could shift the renin-angiotensin system balance towards the protective axis, attenuate cardiac fibrosis remodeling associated with up-regulation of MKP-1 and reduction of MAPKs activities, modulate tachypacing-induced ion channels and connexin remodeling, and subsequently reduce the inducibility and duration of AF.

  3. Experimental study of 31P MR spectroscopy in vitro canine myocardium

    International Nuclear Information System (INIS)

    Gao Fabao; Zhao Haitao; Suo Liping; Zhang Yushun; Fang Hong; Huang Zhilan

    1999-01-01

    Objective: To conduct a dynamic survey of the metabolism of high-energy phosphates in myocardium in order to define, the relationship between the changes in myocardial energy metabolism and the duration of ischemia. Methods: A dynamic survey of isolated heart of 8 dogs was done with the use of 31 P MRS. Results: Myocardial PCr level decreased rapidly after the heart was isolated and was reduced to zero in 2-3 hours. ATP level diminished progressively to its depletion at 6 hours following isolation. Conclusions: After the heart was isolated, the PCr level rapidly decreased and was reduced to zero in 2-3 hours whereas ATP was not depleted until 4-6 hours after isolation. The ATP level remained within normal limits as long as PCr had not been depleted

  4. Comparison of exercise and pharmacologic stress in myocardium perfusion imaging for CHD

    International Nuclear Information System (INIS)

    Li Zebo; Zheng Kangni; Cheng Xiaorui; Liu Hui; Cheng Yihai

    1995-01-01

    In order to provide a proper stress test, exercise, dipyridamole and ATP stress were compared. Three modalities were compared with respect to the detecting rate, methodology, hemodynamic and side effects. There are no significant differences in their ability of detecting coronary heart disease (CHD) (P>0.05). Exercise stress causes an increase in heart rate, blood pressure and myocardium oxygen consumption. Pharmacologic stress cause a slight increase in heart rate, but a decrease in blood pressure (P<0.01). Exercise stress is a basic method with good image quality, but it needs a special equipment. Pharmacologic stress is an easier, cheaper and safer method, particularly useful for patients unable to perform exercise test

  5. Myocardium at risk assessed by electrocardiographic scores and cardiovascular magnetic resonance - a MITOCARE substudy

    DEFF Research Database (Denmark)

    Sejersten, Maria; Fakhri, Yama; Pape, Marianne

    2017-01-01

    Introduction The myocardium at risk (MaR) represents the quantitative ischemic area destined to myocardial infarction (MI) if no reperfusion therapy is initiated. Different ECG scores for MaR have been developed, but there is no consensus as to which should be preferred. Objective Comparisons...... of ECG scores and Cardiac Magnetic Resonance (CMR) for determining MaR. Methods MaR was determined by 3 different ECG scores, and by CMR in ST-segment elevation MI (STEMI) patients from the MITOCARE cardioprotection trial. The Aldrich score (AL) is based on the number of leads with ST-elevation...... for anterior MI and the sum of ST-segment elevation for inferior MI on the admission ECG. The van Hellemond score (VH) considers both the ischemic and infarcted component of the MaR by adding the AL and the QRS score, which is an estimate of final infarct size. The Hasche score is based on the maximal possible...

  6. Isolated noncompaction of myocardium associated with calcification in the interventricular septum.

    Science.gov (United States)

    Nil, M; Mori, K; Yuasa, Y; Ichida, F

    2003-01-01

    We describe a 12-year-old male with isolated noncompaction of the myocardium and associated abnormal calcification in the basal interventricular septum, and we present a review of the literature. The patient has been healthy and free of symptoms. The electrocardiogram showed abnormal Q waves in III, V1, V2, and ST elevation in V1-V3. Exercise testing demonstrated ST depression in V4 and V5. Myocardial scintigraphic examination showed a regional reduction in iodine-1,2,3-beta-methyl-iodophenylpentadecanoic acid uptake in the basal interventricular septum. Since coronary angiography demonstrated normal coronary vessels and the trabeculations were not prominent in this region, we hypothesize that coronary microcirculatory dysfunction may cause subendocardial infarction associated with calcification in the same area.

  7. 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

    2017-03-01

    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). 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. 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'. 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.

  8. Magnetic electroanatomical mapping for ablation of focal atrial tachycardias.

    Science.gov (United States)

    Marchlinski, F; Callans, D; Gottlieb, C; Rodriguez, E; Coyne, R; Kleinman, D

    1998-08-01

    Uniform success for ablation of focal atrial tachycardias has been difficult to achieve using standard catheter mapping and ablation techniques. In addition, our understanding of the complex relationship between atrial anatomy, electrophysiology, and surface ECG P wave morphology remains primitive. The magnetic electroanatomical mapping and display system (CARTO) offers an on-line display of electrical activation and/or signal amplitude related to the anatomical location of the recorded sites in the mapped chamber. A window of electrical interest is established based on signals timed from an electrical reference that usually represents a fixed electrogram recording from the coronary sinus or the atrial appendage. This window of electrical interest is established to include atrial activation prior to the onset of the P wave activity associated with the site of origin of a focal atrial tachycardia. Anatomical and electrical landmarks are defined with limited fluoroscopic imaging support and more detailed global chamber and more focal atrial mapping can be performed with minimal fluoroscopic guidance. A three-dimensional color map representing atrial activation or voltage amplitude at the magnetically defined anatomical sites is displayed with on-line data acquisition. This display can be manipulated to facilitate viewing from any angle. Altering the zoom control, triangle fill threshold, clipping plane, or color range can all enhance the display of a more focal area of interest. We documented the feasibility of using this single mapping catheter technique for localizing and ablating focal atrial tachycardias. In a consecutive series of 8 patients with 9 focal atrial tachycardias, the use of the single catheter CARTO mapping system was associated with ablation success in all but one patient who had a left atrial tachycardia localized to the medial aspect of the orifice of the left atrial appendage. Only low power energy delivery was used in this patient because of the

  9. Fractional flow reserve guided percutaneous coronary intervention results in reduced ischemic myocardium and improved outcomes.

    Science.gov (United States)

    Sawant, Abhishek C; Bhardwaj, Aishwarya; Banerjee, Kinjal; Jobanputra, Yash; Kumar, Arnav; Parikh, Parth; Kandregula, Krishna C; Poddar, Kanhaiya; Ellis, Stephen G; Nair, Ravi; Corbelli, John; Kapadia, Samir

    2018-02-06

    To determine if fractional flow reserve guided percutaneous coronary intervention (FFR-guided PCI) is associated with reduced ischemic myocardium compared with angiography-guided PCI. Although FFR-guided PCI has been shown to improve outcomes, it remains unclear if it reduces the extent of ischemic myocardium at risk compared with angiography-guided PCI. We evaluated 380 patients (190 FFR-guided PCI cases and 190 propensity-matched controls) who underwent PCI from 2009 to 2014. Clinical, laboratory, angiographic, stress testing, and major adverse cardiac events [MACE] (all-cause mortality, recurrence of MI requiring PCI, stroke) data were collected. Mean age was 63 ± 11 years; the majority of patients were males (76%) and Caucasian (77%). Median duration of follow up was 3.4 [Range: 1.9, 5.0] years. Procedural complications including coronary dissection (2% vs. 0%, P = .12) and perforation (0% vs. 0%, P = 1.00) were similar between FFR-guided and angiography-guided PCI patients. FFR-guided PCI patients had lower unadjusted (14.7% vs. 23.2%, P = .04) and adjusted [OR = 0.58 (95% CI: 0.34-0.98)] risk of repeat revascularization at one year. FFR-guided PCI patients were less likely (23% vs. 32%, P = .02) to have ischemia and had lower (5.9% vs. 21.1%, P guided PCI, FFR-guided PCI results in less repeat revascularization and a lower incidence of post PCI ischemia translating into improved survival, without an increase in complications. © 2018 Wiley Periodicals, Inc.

  10. Constitutive activation of Nrf2 induces a stable reductive state in the mouse myocardium

    Directory of Open Access Journals (Sweden)

    Gobinath Shanmugam

    2017-08-01

    Full Text Available Redox homeostasis regulates key cellular signaling pathways in both physiology and pathology. The cell's antioxidant response provides a defense against oxidative stress and establishes a redox tone permissive for cell signaling. The molecular regulation of the well-known Keap1/Nrf2 system acts as sensor responding to changes in redox homeostasis and is poorly studied in the heart. Importantly, it is not yet known whether Nrf2 alone can serve as a master regulator of cellular redox homeostasis without compensation of the transcriptional regulation of antioxidant response element (ARE genes through alternate mechanisms. Here, we addressed this question using cardiac-specific transgenic expression at two different levels of constitutively active nuclear erythroid related factor 2 (caNrf2 functioning independently of Keap1. The caNrf2 mice showed augmentation of glutathione (GSH, the key regulator of the cellular thiol redox state. The Trans-AM assay for Nrf2-binding to the antioxidant response element (ARE showed a dose-dependent increase associated with upregulation of several major antioxidant genes and proteins. This was accompanied by a significant decrease in dihydroethidium staining and malondialdehyde (MDA in the caNrf2-TG mice myocardium. Interestingly, caNrf2 gene-dosage dependent redox changes were noted resulting in generation of a multi-stage model of pro-reductive and reductive conditions in the myocardium of TG-low and TG-high mice, respectively. These data clearly show that Nrf2 levels alone are capable of serving as the master regulator of the ARE. These models provide an important platform to investigate the impact of the Nrf2 system independent of the need to regulate the activity of Keap1 and the consequent exposure to pro-oxidants or electrophiles, which have numerous off-target effects.

  11. Retention and clearance of C-11 palmitic acid in ischemic and reperfused canine myocardium

    International Nuclear Information System (INIS)

    Schwaiger, M.; Schelbert, H.R.; Keen, R.; Vinten-Johansen, J.; Hansen, H.; Selin, C.; Barrio, J.; Huang, S.C.; Phelps, M.E.

    1985-01-01

    Free fatty acids are the major energy source for cardiac muscle. Oxidation of fatty acid decreases or even ceases during ischemia. Its recovery after transient ischemia remains largely unexplored. Using intracoronary carbon-11 palmitic acid as a tracer of myocardial fatty acid metabolism in an open chest dog model, retention and clearance of tracer in myocardium were evaluated at control, during ischemia and after reperfusion following a 20 minute occlusion of the left anterior descending coronary artery. Myocardial C-11 time-activity curves were analyzed with biexponential curve-fitting routines yielding fractional distribution and clearance half-times of C-11 palmitic acid in myocardial tissue. In animals with permanent occlusion and intracoronary injection of C-11 palmitic acid distal to the occlusion site, the relative size and half-time of the early clearance curve component differed markedly from control values and did not change with ongoing ischemia. Conversely, in animals with only 20 minutes of coronary occlusion, the relative size of the early C-11 clearance phase was still significantly depressed at 20 and 90 minutes of reperfusion but returned to control level at 180 minutes. Tissue C-11 clearance half-times remained significantly prolonged throughout the reperfusion period. Regional function in reperfused myocardium monitored with ultrasonic crystals recovered slowly and was still less than control after 3 hours of reperfusion. The data indicate that after transient ischemia, myocardial fatty acid metabolism fails to recover immediately. Because the metabolic recovery occurs in parallel with recovery of regional function, C-11 palmitic acid in conjunction with positron tomography may be useful for studying regional fatty acid metabolism noninvasively after an ischemic injury, and may be helpful in identifying reversible tissue injury

  12. Hyperthyroidism causes mechanical insufficiency of myocardium with possibly increased SR Ca2+-ATPase activity.

    Science.gov (United States)

    Takeuchi, Koh; Minakawa, M; Otaki, M; Odagiri, S; Itoh, K; Murakami, A; Yaku, H; Kitamura, N

    2003-12-01

    Hyperthyroidism is known to affect multiple organ functions, and thyroid hormone has been known to improve myocardial function in a failing heart. The purpose of this study is to elucidate the functional and metabolic effects of thyroid hormone on myocardium in a rat model exposed to long-term excess thyroid hormone, particularly focusing on the SR Ca(2+)-ATPase (SERCA2) function. 3,5,3'-Triiodo-L-thyronine (T3), or the vehicle, was subcutaneously given for 4 weeks (T3 and control [C] group). Bolus I.V. Thapsigargin (TG) was used to test the SERCA2 function (C-TG and T3-TG) in Langendorff perfused heart. Myocardial functions such as LV-developed pressure (LVDP; mmHg), +/- dP/dt (mmHg/s), tau (ms), and oxygen consumption (MVO(2); ml/min/g wt) were measured. SERCA2 and GLUT4 protein level were also evaluated by Western immunoblotting. Left ventricle to body weight (LV/BW) ratio was significantly higher in the T3 group. Both negative dP/dt and tau were significantly decreased by TG. It is interesting that the decrement of negative dP/dt and tau attained by TG was significantly larger in the hyperthyroid group (T3-TG) than in a normal heart (C-TG). SERCA2 and GLUT4 protein levels were not significantly different between control and the T3 group. We conclude that prolonged exposure to thyroid hormone causes hypertrophy of the myocardium and an augmentation of the SR Ca(2+) ATPase activity. Care must be taken in hyperthyroid heart during the ischemia-reperfusion process where the SRECA2 function is inhibited.

  13. Characterization of the Structural and Functional Changes in the Myocardium Following Focal Ischemia-Reperfusion Injury

    Science.gov (United States)

    Ojha, Navdeep; Roy, Sashwati; Radtke, Jared; Simonetti, Orlando; Gnyawali, Surya; Zweier, Jay L.; Kuppusamy, Periannan; Sen, Chandan K.

    2015-01-01

    High resolution (11.7T) cardiac magnetic resonance imaging (MRI) and histological approaches have been employed in tandem to characterize the secondary damage suffered by the murine myocardium following the initial insult caused by ischemia-reperfusion (IR). IR induced changes in the myocardium were examined in five separate groups at the following time-points after IR: 1h, 1d, 3d, 7d and 14 d. Infarct volume increased from 1h to 1d post-IR. Over time, loss of myocardial function was observed to be associated with increased infarct volume and worsened regional wall motion. In the infarct region, IR caused a decrease in end-systolic thickness coupled with small changes in end-diastolic thickness, leading to massive wall thickening abnormalities. In addition, compromised wall thickening was also observed in left ventricular regions adjacent to the infarct region. A tight correlation (r2 = 0.86) between measured MRI and triphenyltetrazolium chloride (TTC) infarct volumes was noted. Our observation that until day 3 post-IR, the infarct size as measured by TTC staining and MRI were much larger than the myocyte-silent regions in trichrome or H&E stained sections is consistent with the literature and leads to the conclusion that at such early phase the infarct site contains structurally intact myocytes that are functionally compromised. Over time, such affected myocytes were noted to structurally disappear resulting in consistent infarct sizes obtained from MRI, TTC as well as trichrome and hematoxylin/eosin analyses on day 7 following IR. Myocardial remodeling following IR includes secondary myocyte death followed by loss of cardiac function over time. PMID:18375718

  14. Miocárdio hibernante: uma realidade clínica Hibernant myocardium: a clinical reality

    Directory of Open Access Journals (Sweden)

    J.A. Marin-Neto

    1997-12-01

    Full Text Available O conceito da hibernação miocárdica implica a ocorrência de disfunção ventricular crônica, potencialmente reversível, causada por dissinergia regional, dependente de isquemia prolongada. Não tem fisiopatologia elucidada, em parte porque não existem modelos experimentais satisfatórios para seu estudo. Diversos métodos são capazes de demonstrar viabilidade miocárdica nas regiões que não exibem capacidade contrátil basal. O desmascaramento da hibernação nesses territórios pode ser feito mediante demonstração de reserva contrátil, de funcionamento normal da membrana celular, ou de metabolismo preservado. A correta identificação de miocárdio hibernante reveste-se de especial significado clínico, por suas implicações prognósticas quanto a intervenções de revascularização miocárdica, destinadas a reabilitar a função ventricular em muitos pacientes coronariopatas crônicos.Myocardial hibernation is believed to occur in ventricular dyssynergic regions chronically deprived of coronary flow enough to warrant the preservation of contractile function. Pathophysiology of this condition remains largely unclear, mainly because good experimental models for its study are still lacking. Various methods can be clinically employed to detect hibernation in patients with chronic ventricular dysfunction. These methods use the principle of unmasking contractile reserve, or are based on the demonstration of preserved membrane function or myocardium metabolism in the dyssynergic regions. The correct identification of viable hibernating myocardium is crucial in the process of deciding which coronary disease patients would potentially benefit from revascularization procedures.

  15. Quantitative shear wave imaging optical coherence tomography for noncontact mechanical characterization of myocardium

    Science.gov (United States)

    Wang, Shang; Lopez, Andrew L.; Morikawa, Yuka; Tao, Ge; Li, Jiasong; Larina, Irina V.; Martin, James F.; Larin, Kirill V.

    2015-03-01

    Optical coherence elastography (OCE) is an emerging low-coherence imaging technique that provides noninvasive assessment of tissue biomechanics with high spatial resolution. Among various OCE methods, the capability of quantitative measurement of tissue elasticity is of great importance for tissue characterization and pathology detection across different samples. Here we report a quantitative OCE technique, termed quantitative shear wave imaging optical coherence tomography (Q-SWI-OCT), which enables noncontact measurement of tissue Young's modulus based on the ultra-fast imaging of the shear wave propagation inside the sample. A focused air-puff device is used to interrogate the tissue with a low-pressure short-duration air stream that stimulates a localized displacement with the scale at micron level. The propagation of this tissue deformation in the form of shear wave is captured by a phase-sensitive OCT system running with the scan of the M-mode imaging over the path of the wave propagation. The temporal characteristics of the shear wave is quantified based on the cross-correlation of the tissue deformation profiles at all the measurement locations, and linear regression is utilized to fit the data plotted in the domain of time delay versus wave propagation distance. The wave group velocity is thus calculated, which results in the quantitative measurement of the Young's modulus. As the feasibility demonstration, experiments are performed on tissuemimicking phantoms with different agar concentrations and the quantified elasticity values with Q-SWI-OCT agree well with the uniaxial compression tests. For functional characterization of myocardium with this OCE technique, we perform our pilot experiments on ex vivo mouse cardiac muscle tissues with two studies, including 1) elasticity difference of cardiac muscle under relaxation and contract conditions and 2) mechanical heterogeneity of the heart introduced by the muscle fiber orientation. Our results suggest the

  16. Right and Left Ventricular Volumes in Atrial Septal Defect Studied by Radiocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Ivancevic, D. [Radioisotope Department, Internal Clinic, Rebro, Zagreb, Yugoslavia (Croatia); Vernejoul, P. de; Kellershohn, C. [CEA, Service Hospitalier Frederic Joliot, Departement de Biologie, Orsay (France)

    1971-02-15

    Radiocardiography with radioiodinated ({sup 131}I) human serum albumin and barium ({sup 137m}Ba) solution injected into the right subclavian vein has been performed in a group of 43 patients with atrial septal defect and left-to-right shunt. Data on the output and ejection index of each ventricle are essential for the estimation of the diastolic and residual volumes of the right and left ventricle. The systemic flow was therefore calculated according to Veall's formula and the pulmonary flow and the shunt How were determined using the method of de Vernejoul and co-workers. The formulas for the calculation of ventricular volumes were modified. The results show that many cases of atrial septal defect have an enlarged right ventricle whereas the left ventricle remains normal or is diminished. These changes correlate well with the amount of the shunt flow. In both ventricles the ventricular volumes show a good correlation with the stroke volumes. For the regulation of the pulmonary blood volume the right ventricle seems to be more important than the left ventricle. The operative closure of atrial septal defect (in 14 patients) has normalized the size of ventricular volumes. (author)

  17. [Quantitative Measurements on the Blood Flow Fields of Left Atrial Appendage using Vector Flow Mapping in Patients with Nonvalvular Atrial Fibrillation].

    Science.gov (United States)

    Cai, Yu-Yan; Wei, Xin; Zhang, Xiao-Ling; Liu, Gu-Yue; Li, Xi; Tang, Hong

    2018-01-01

    To quantify the hemodynamic characteristics of patients with nonvalvular atrial fibrillation. Twenty patients with paroxysmal atrial fibrillation and 15 patients with persistent atrial fibrillation enrolled in this study,while 12 patients with sinus rhythms served as controls. The hemodynamic characteristics of the patients in left atrial appendage were measured by transesophageal echocardiography (TEE) and vector flow mapping (VFM) using indicators such as vectors,vortex and energy loss (EL). ① Significant differences appeared between the patients with atrial fibrillation and the controls in heart rate,size of left atrium,size of left atrial appendage (LAA),and velocities of LAA filling and emptying. ② Regular vectors in LAA in early systole and late diastole were found in the patients with paroxysmal atrial fibrillation and the controls; whereas,irregular vectors with direction alternating were visualized in the whole cardiac cycle in the patients with persistent atrial fibrillation. ③ Small vortexes were observed at the opening of the left atrial appendage in late diastole in the patients with paroxysmal atrial fibrillation and the controls. ④ Peak EL values occurred in early systole and late diastole in the patients with paroxysmal atrial fibrillation and the controls. But the patients with persistent atrial fibrillation had increased EL values over the whole cardiac cycle. VFM can visualize and quantify the hemodynamics of LAA in patients with different heart rhythms. It may provide a new method for assessing atrial fibrillation. CopyrightCopyright© by Editorial Board of Journal of Sichuan University (Medical Science Edition).

  18. 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

  19. 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.

  20. Noninvasive evaluation of reverse atrial remodeling after catheter ablation of atrial fibrillation by P wave dispersion.

    Science.gov (United States)

    Fujimoto, Yuhi; Yodogawa, Kenji; Takahashi, Kenta; Tsuboi, Ippei; Hayashi, Hiroshi; Uetake, Shunsuke; Iwasaki, Yu-Ki; Hayashi, Meiso; Miyauchi, Yasushi; Shimizu, Wataru

    2017-11-01

    Atrial fibrillation (AF) itself creates structural and electrophysiological changes such as atrial enlargement, shortening of refractory period and decrease in conduction velocity, called "atrial remodeling", promoting its persistence. Although the remodeling process is considered to be reversible, it has not been elucidated in detail. The aim of this study was to assess the feasibility of P wave dispersion in the assessment of reverse atrial remodeling following catheter ablation of AF. Consecutive 126 patients (88 males, age 63.0 ± 10.4 years) who underwent catheter ablation for paroxysmal AF were investigated. P wave dispersion was calculated from the 12 lead ECG before, 1 day, 1 month, 3 months and 6 months after the procedure. Left atrial diameter (LAD), left atrial volume index (LAVI), left ventricular ejection fraction (LVEF), transmitral flow velocity waveform (E/A), and tissue Doppler (E/e') on echocardiography, plasma B-type natriuretic peptide (BNP) concentrations, serum creatinine, and estimated glomerular filtration rate (eGFR) were also measured. Of all patients, 103 subjects remained free of AF for 1 year follow-up. In these patients, P wave dispersion was not changed 1 day and 1 month after the procedure. However, it was significantly decreased at 3 and 6 months (50.1 ± 14.8 to 45.4 ± 14.4 ms, p < 0.05, 45.2 ± 9.9 ms, p < 0.05, respectively). Plasma BNP concentrations, LAD and LAVI were decreased (81.1 ± 103.8 to 44.8 ± 38.3 pg/mL, p < 0.05, 38.2 ± 5.7 to 35.9 ± 5.6 mm, p < 0.05, 33.3 ± 14.2 to 29.3 ± 12.3 mL/m 2 , p < 0.05) at 6 months after the procedure. There were no significant changes in LVEF, E/A, E/e', serum creatinine, and eGFR during the follow up period. P wave dispersion was decreased at 3 and 6 months after catheter ablation in patients without recurrence of AF. P wave dispersion is useful for assessment of reverse remodeling after catheter ablation of AF.

  1. 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. © 2015 Wiley Periodicals, Inc.

  2. Right atrial bypass model in the dog.

    Science.gov (United States)

    Breen, P H; Isserles, S A

    1995-02-01

    In gas exchange studies addressing the storage and transport of CO2 in dogs, a model in which cardiac output (QT) can be precisely controlled and measured would be beneficial. We identified problems with described extracorporeal circuits and implemented right atrial bypass (RAB) in dogs. In 6 anesthetized (chloralose and urethane), heparinized dogs (mean +/- SD, 24 +/- 4 kg) with open thorax, cannulas were inserted in both vena cavas to drain venous blood return to a reservoir (anaerobic bag or bubble oxygenator). A roller pump then drove blood through a heat exchanger back to the right atrial appendage. After 1.8 +/- 1.4 hour of RAB, physiologic variables remained within reference limits for dogs (QT, 1.5 +/- 0.3 L/min; blood pressure, 92 +/- 25 mm of Hg; arterial PCO2, 35 +/- 4 mm of Hg; PO2, 513 +/- 39 mm of Hg; pH, 7.39 +/- 0.08; and tissue CO2 production, 126 +/- 56 ml/min). To permit study of gas exchange, venous return (and thus, QT) and venous PCO2 and PO2 could be accurately regulated and measured over a wide range. Maintenance of native pulsatile lung perfusion and cardiogenic oscillations minimizes mismatching of pulmonary ventilation and perfusion and facilitates studies addressing pulmonary gas exchange. This RAB model is designed so that investigators can establish the preparation in a few hours.

  3. Atrial SERCA2a Overexpression Has No Affect on Cardiac Alternans but Promotes Arrhythmogenic SR Ca2+ Triggers.

    Science.gov (United States)

    Nassal, Michelle M J; Wan, Xiaoping; Laurita, Kenneth R; Cutler, Michael J

    2015-01-01

    Atrial fibrillation (AF) is the most common arrhythmia in humans, yet; treatment has remained sub-optimal due to poor understanding of the underlying mechanisms. Cardiac alternans precede AF episodes, suggesting an important arrhythmia substrate. Recently, we demonstrated ventricular SERCA2a overexpression suppresses cardiac alternans and arrhythmias. Therefore, we hypothesized that atrial SERCA2a overexpression will decrease cardiac alternans and arrhythmias. Adult rat isolated atrial myocytes where divided into three treatment groups 1) Control, 2) SERCA2a overexpression (Ad.SERCA2a) and 3) SERCA2a inhibition (Thapsigargin, 1μm). Intracellular Ca2+ was measured using Indo-1AM and Ca2+ alternans (Ca-ALT) was induced with a standard ramp pacing protocol. As predicted, SR Ca2+ reuptake was enhanced with SERCA2a overexpression (poverexpression or inhibition when compared to controls (p = 0.73). In contrast, SERCA2a overexpression resulted in increased premature SR Ca2+ (SCR) release compared to control myocytes (28% and 0%, p overexpression in atrial myocytes can increase SCR, which may be arrhythmogenic.

  4. Long-range regulatory interactions at the 4q25 atrial fibrillation risk locus involve PITX2c and ENPEP.

    Science.gov (United States)

    Aguirre, Luis A; Alonso, M Eva; Badía-Careaga, Claudio; Rollán, Isabel; Arias, Cristina; Fernández-Miñán, Ana; López-Jiménez, Elena; Aránega, Amelia; Gómez-Skarmeta, José Luis; Franco, Diego; Manzanares, Miguel

    2015-04-17

    Recent genome-wide association studies have uncovered genomic loci that underlie an increased risk for atrial fibrillation, the major cardiac arrhythmia in humans. The most significant locus is located in a gene desert at 4q25, approximately 170 kilobases upstream of PITX2, which codes for a transcription factor involved in embryonic left-right asymmetry and cardiac development. However, how this genomic region functionally and structurally relates to PITX2 and atrial fibrillation is unknown. To characterise its function, we tested genomic fragments from 4q25 for transcriptional activity in a mouse atrial cardiomyocyte cell line and in transgenic mouse embryos, identifying a non-tissue-specific potentiator regulatory element. Chromosome conformation capture revealed that this region physically interacts with the promoter of the cardiac specific isoform of Pitx2. Surprisingly, this regulatory region also interacts with the promoter of the next neighbouring gene, Enpep, which we show to be expressed in regions of the developing mouse heart essential for cardiac electrical activity. Our data suggest that de-regulation of both PITX2 and ENPEP could contribute to an increased risk of atrial fibrillation in carriers of disease-associated variants, and show the challenges that we face in the functional analysis of genome-wide disease associations.

  5. Pulmonary edema following transcatheter closure of atrial septal defect

    Directory of Open Access Journals (Sweden)

    Keerthi Chigurupati

    2015-01-01

    Full Text Available We describe an incident of development of acute pulmonary edema after the device closure of a secundum atrial septal defect in a 52-year-old lady, which was treated with inotropes, diuretics and artificial ventilation. Possibility of acute left ventricular dysfunction should be considered after the defect closure in the middle-aged patients as the left ventricular compliance may be reduced due to increased elastic stiffness and diastolic dysfunction. Baseline left atrial pressure may be > 10 mmHg in these patients. Associated risk factors for the left ventricular dysfunction are a large Qp:Qs ratio, systemic hypertension, severe pulmonary hypertension and paroxysmal atrial fibrillation.

  6. The immediate future for the medical treatment of atrial fibrillation

    DEFF Research Database (Denmark)

    Pedersen, Ole Dyg; Brendorp, Bente; Køber, Lars

    2002-01-01

    ) the rhythm causes loss of atrioventricular synchrony, which reduces diastolic filling and may lead to heart failure; and iii) atrial contraction is lost leading to stagnant blood that again may lead to atrial thrombi and peripheral embolism. Thus, the treatment of atrial fibrillation is focused...... on the maintenance of sinus rhythm, rate control and prevention of embolism. For the maintenance of sinus rhythm, all drugs under current development are potassium channel blockers; the so-called class III anti-arrhythmic drugs. Those which have been further investigated appear to be valuable for maintenance...

  7. Acute Pulmonary Edema Caused by a Giant Atrial Myxoma

    Directory of Open Access Journals (Sweden)

    Andrea Fisicaro

    2013-01-01

    Full Text Available Atrial myxoma is the most common primary cardiac tumor. Its clinical presentation spreads from asymptomatic incidental mass to serious life-threatening cardiovascular complications. We report the case of a 44-year-old man with evening fever and worsening dyspnea in the last weeks, admitted to our hospital for acute pulmonary edema. The cardiac auscultation was very suspicious for mitral valve stenosis, but the echocardiography revealed a huge atrial mass with a diastolic prolapse into mitral valve orifice causing an extremely high transmitral gradient pressure. Awareness of this uncommon acute presentation of atrial myxoma is necessary for timely diagnosis and prompt surgical intervention.

  8. Atrial Septal Aneurysm Presenting as Clubbing without Clinically Apparent Cyanosis.

    Science.gov (United States)

    Goyal, Laxmi Kant; Banerjee, S; Yadav, R N; Singh, Gajraj; Ganguli, Sujata; Isran, Rohit

    2015-09-01

    Atrial septal aneurysm (ASA) is a localised "saccular" deformity which protrudes to the right or the left atrium or on both sides. It is a rare, but well recognised cardiac abnormality. It is usually an incidental finding or may presents as atrial arrhythmias or arterial embolism. Though it is an acyanotic congenital heart disease but it may result in significant right to left shunt and cyanosis. We describe a patient of ASA with atrial septal defect who presented with clubbing and right to left shunt without clinically apparent cyanosis. © Journal of the Association of Physicians of India 2011.

  9. Atrial natriuretic peptide and feeding activity patterns in rats

    Directory of Open Access Journals (Sweden)

    Oliveira M.H.A.

    1997-01-01

    Full Text Available This review presents historical data about atrial natriuretic peptide (ANP from its discovery as an atrial natriuretic factor (ANF to its role as an atrial natriuretic hormone (ANH. As a hormone, ANP can interact with the hypothalamic-pituitary-adrenal axis (HPA-A and is related to feeding activity patterns in the rat. Food restriction proved to be an interesting model to investigate this relationship. The role of ANP must be understood within a context of peripheral and central interactions involving different peptides and pathways

  10. 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

    by Jakobsen and colleagues. We plan to include all relevant randomised clinical trials assessing the effects of any rhythm control strategy versus any rate control strategy. We plan to search the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS, Science Citation Index Expanded...... on Web of Science, and BIOSIS to identify relevant trials. Any eligible trial will be assessed and classified as either high risk of bias or low risk of bias, and our conclusions will be based on trials with low risk of bias. The analyses of the extracted data will be performed using Review Manager 5....... This protocol for a systematic review aims at identifying the best overall treatment strategy for atrial fibrillation and atrial flutter. METHODS: This protocol for a systematic review was performed following the recommendations of the Cochrane Collaboration and the eight-step assessment procedure suggested...

  11. Left Atrial Appendage Closure in Atrial Fibrillation: A World without Anticoagulation?

    Directory of Open Access Journals (Sweden)

    Tahmeed Contractor

    2011-01-01

    Full Text Available Atrial Fibrillation (AF is a common arrhythmia with an incidence that is as high as 10% in the elderly population. Given the large proportion of strokes caused by AF as well as the associated morbidity and mortality, reducing stroke burden is the most important part of AF management. While warfarin significantly reduces the risk of AF-related stroke, perceived bleeding risks and compliance limit its widespread use in the high-risk AF population. The left atrial appendage is believed to be the “culprit” for thrombogenesis in nonvalvular AF and is a new therapeutic target for stroke prevention. The purpose of this review is to explore the evolving field of percutaneous LAA occlusion. After briefly highlighting the risk of stroke with AF, problems with warfarin, and the role of the LAA in clot formation, this article discusses the feasibility and efficacy of various devices which have been developed for percutaneous LAA occlusion.

  12. Surface atrial frequency analysis in patients with atrial fibrillation: a tool for evaluating the effects of intervention.

    Science.gov (United States)

    Raine, Dan; Langley, Philip; Murray, Alan; Dunuwille, Asunga; Bourke, John P

    2004-09-01

    The aims of this study were to evaluate (1) principal component analysis as a technique for extracting the atrial signal waveform from the standard 12-lead ECG and (2) its ability to distinguish changes in atrial fibrillation (AF) frequency parameters over time and in response to pharmacologic manipulation using drugs with different effects on atrial electrophysiology. Twenty patients with persistent AF were studied. Continuous 12-lead Holter ECGs were recorded for 60 minutes, first, in the drug-free state. Mean and variability of atrial waveform frequency were measured using an automated computer technique. This extracted the atrial signal by principal component analysis and identified the main frequency component using Fourier analysis. Patients were then allotted sequentially to receive 1 of 4 drugs intravenously (amiodarone, flecainide, sotalol, or metoprolol), and changes induced in mean and variability of atrial waveform frequency measured. Mean and variability of atrial waveform frequency did not differ within patients between the two 30-minute sections of the drug-free state. As hypothesized, significant changes in mean and variability of atrial waveform frequency were detected after manipulation with amiodarone (mean: 5.77 vs 4.86 Hz; variability: 0.55 vs 0.31 Hz), flecainide (mean: 5.33 vs 4.72 Hz; variability: 0.71 vs 0.31 Hz), and sotalol (mean: 5.94 vs 4.90 Hz; variability: 0.73 vs 0.40 Hz) but not with metoprolol (mean: 5.41 vs 5.17 Hz; variability: 0.81 vs 0.82 Hz). A technique for continuously analyzing atrial frequency characteristics of AF from the surface ECG has been developed and validated.

  13. Effect of left ventricular diastolic dysfunction on left atrial appendage function and thrombotic potential in nonvalvular atrial fibrillation.

    Science.gov (United States)

    Demirçelik, Muhammed Bora; Çetin, Mustafa; Çiçekcioğlu, Hülya; Uçar, Özgül; Duran, Mustafa

    2014-05-01

    We aimed to investigate effects of left ventricular diastolic dysfunction on left atrial appendage functions, spontaneous echo contrast and thrombus formation in patients with nonvalvular atrial fibrillation. In 58 patients with chronic nonvalvular atrial fibrilation and preserved left ventricular systolic function, left atrial appendage functions, left atrial spontaneous echo contrast grading and left ventricular diastolic functions were evaluated using transthoracic and transoesophageal echocardiogram. Patients divided in two groups: Group D (n=30): Patients with diastolic dysfunction, Group N (n=28): Patients without diastolic dysfunction. Categorical variables in two groups were evaluated with Pearson's chi-square or Fisher's exact test. The significance of the lineer correlation between the degree of spontaneous echo contrast (SEC) and clinical measurements was evaluated with Spearman's correlation analysis. Peak pulmonary vein D velocity of the Group D was significantly higher than the Group N (p=0.006). However, left atrial appendage emptying velocity, left atrial appendage lateral wall velocity, peak pulmonary vein S, pulmonary vein S/D ratio were found to be significantly lower in Group D (p=0.028, patrial appendage emptying, filling, pulmonary vein S/D levels and lateral wall velocities respectively (r=-0.438, r=-0.328, r=-0.233, r=-0.447). Left atrial appendage emptying, filling, pulmonary vein S/D levels and lateral wall velocities were significantly lower in SEC 2-3-4 than SEC 1 (p=0.003, p=0.029, patrial fibrillation and preserved left ventricular ejection fraction, left atrial appendage functions are decreased in patients with left ventricular diastolic dysfunction. Left ventricular diastolic dysfunction may constitute a potential risk for formation of thrombus and stroke.

  14. Assessment of left atrial volume and function in patients with permanent atrial fibrillation

    DEFF Research Database (Denmark)

    Agner, Bue F Ross; Kühl, Jørgen Tobias; Linde, Jesper James

    2014-01-01

    Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with substantial morbidity and mortality. AF is associated with enlargement of the left atrium (LA), and the LA volume has important prognostic implications for the disease. The objective of the study was to determine how...... measurements of LA volume and function obtained by transthoracic echocardiography (TTE), cardiac magnetic resonance (CMR), and 320-slice multi-detector computed tomography (MDCT) correlate in patients with permanent AF....

  15. Three-dimensional atrial wall thickness maps to inform catheter ablation procedures for atrial fibrillation.

    Science.gov (United States)

    Bishop, Martin; Rajani, Ronak; Plank, Gernot; Gaddum, Nicholas; Carr-White, Gerry; Wright, Matt; O'Neill, Mark; Niederer, Steven

    2016-03-01

    Transmural lesion formation is critical to success in atrial fibrillation ablation and is dependent on left atrial wall thickness (LAWT). Pre- and peri-procedural planning may benefit from LAWT measurements. To calculate the LAWT, the Laplace equation was solved over a finite element mesh of the left atrium derived from the segmented computed tomographic angiography (CTA) dataset. Local LAWT was then calculated from the length of field lines derived from the Laplace solution that spanned the wall from the endocardium or epicardium. The method was validated on an atrium phantom and retrospectively applied to 10 patients who underwent routine coronary CTA for standard clinical indications at our institute. The Laplace wall thickness algorithm was validated on the left atrium phantom. Wall thickness measurements had errors of atrial wall thickness measurements were performed on 10 patients. Successful comprehensive LAWT maps were generated in all patients from the coronary CTA images. Mean LAWT measurements ranged from 0.6 to 1.0 mm and showed significant inter and intra patient variability. Left atrial wall thickness can be measured robustly and efficiently across the whole left atrium using a solution of the Laplace equation over a finite element mesh of the left atrium. Further studies are indicated to determine whether the integration of LAWT maps into pre-existing 3D anatomical mapping systems may provide important anatomical information for guiding radiofrequency ablation. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  16. Galectin-3 as a marker of interstitial atrial remodelling involved in atrial fibrillation

    OpenAIRE

    Diana Hernández-Romero; Juan Antonio Vílchez; Álvaro Lahoz; Ana I. Romero-Aniorte; Eva Jover; Arcadio García-Alberola; Rubén Jara-Rubio; Carlos M. Martínez; Mariano Valdés; Francisco Marín

    2017-01-01

    Remodelling in the atria could appear as a result of hypertension, diabetes or ischaemic heart disease. Galectin-3 (Gal-3) is a mediator of profibrotic pathways and a potential biomarker of cardiac remodelling. We prospectively recruited consecutive patients undergoing elective cardiac surgery. Preoperative Gal-3 levels were determined from serum samples, and the presence of fibrosis was assessed from atrial appendage tissue samples obtained during cardiac surgery. We included 100 patients wi...

  17. Development of a transgenic goat model wih cardiac-specific overexpression of transforming growth factor - {beta} 1 to study the relationship between atrial fibrosis and atrial fibrillation

    Science.gov (United States)

    Studies on patients, large animal models and transgenic mouse models have shown a strong association of atrial fibrosis with atrial fibrillation (AF). However, it is unclear whether there is a causal relationship between atrial fibrosis and AF or whether these events appear as a result of independen...

  18. Left atrial appendage thrombosis during therapy with rivaroxaban in elective cardioversion for permanent atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Walter Serra

    2015-09-01

    Full Text Available Electric external cardioversion (EEC for permanent atrial fibrillation (AF carries a risk of thromboembolic events (TE. The use of transesophageal echocardiography (TEE to guide the management of atrial fibrillation may be considered a clinically effective alternative strategy to conventional therapy for patients in whom elective cardioversion is planned. Therapeutic anticoagulation with novel oral anticoagulants (NOAC is recommended for 3 to 4 weeks before and an anticoagulation life-long therapy is recommended after EEC to reduce TE, in patients with high CHA2DS2-VASc score; however, only few data are currently available about safety of shortterm anticoagulation with NOAC in the setting of EEC. Patients with increased risk of thromboembolism have not been adequately studied and the monitoring of anticoagulant effects can also have important benefits in case of drug interactions. We report a case of a 68-year old man with AF from September 2014. Moderate depression of global left ventricular systolic function was detected by echocardiographic exam. On the basis of a high thromboembolic risk, an anticoagulant therapy with rivaroxaban, at the dose of 20 mg/day, was started. TEE showed a thrombus in the left atrial appendage. This case demonstrates the utility of performing TEE prior than EEC in patients with hypokinetic cardiomyopathy other than AF in therapy with NOAC. We underline the presence of significant pharmacodynamic interference of rivaroxaban with other drugs such as oxcarbazepine.

  19. Limitations of Dower's inverse transform for the study of atrial loops during atrial fibrillation.

    Science.gov (United States)

    Guillem, María S; Climent, Andreu M; Bollmann, Andreas; Husser, Daniela; Millet, José; Castells, Francisco

    2009-08-01

    Spatial characteristics of atrial fibrillatory waves have been extracted by using a vectorcardiogram (VCG) during atrial fibrillation (AF). However, the VCG is usually not recorded in clinical practice and atrial loops are derived from the 12-lead electrocardiogram (ECG). We evaluated the suitability of the reconstruction of orthogonal leads from the 12-lead ECG for fibrillatory waves in AF. We used the Physikalisch-Technische Bundesanstalt diagnostic ECG database, which contains 15 simultaneously recorded signals (12-lead ECG and three Frank orthogonal leads) of 13 patients during AF. Frank leads were derived from the 12-lead ECG by using Dower's inverse transform. Derived leads were then compared to true Frank leads in terms of the relative error achieved. We calculated the orientation of AF loops of both recorded orthogonal leads and derived leads and measured the difference in estimated orientation. Also, we investigated the relationship of errors in derivation with fibrillatory wave amplitude, frequency, wave residuum, and fit to a plane of the AF loops. Errors in derivation of AF loops were 68 +/- 31% and errors in the estimation of orientation were 35.85 +/- 20.43 degrees . We did not find any correlation among these errors and amplitude, frequency, or other parameters. In conclusion, Dower's inverse transform should not be used for the derivation of orthogonal leads from the 12-lead ECG for the analysis of fibrillatory wave loops in AF. Spatial parameters obtained after this derivation may differ from those obtained from recorded orthogonal leads.

  20. Correlation of right atrial appendage velocity with left atrial appendage velocity and brain natriuretic Peptide.

    Science.gov (United States)

    Kim, Bu-Kyung; Heo, Jung-Ho; Lee, Jae-Woo; Kim, Hyun-Soo; Choi, Byung-Joo; Cha, Tae-Joon

    2012-03-01

    Left atrial appendage (LAA) anatomy and function have been well characterized both in healthy and diseased people, whereas relatively little attention has been focused on the right atrial appendage (RAA). We sought to evaluate RAA flow velocity and to compare these parameters with LAA indices and with a study of biomarkers, such as brain natriuretic peptide, among patients with sinus rhythm (SR) and atrial fibrillation (AF). In a series of 79 consecutive patients referred for transesophageal echocardiography, 43 patients (23 with AF and 20 controls) were evaluated. AF was associated with a decrease in flow velocity for both LAA and RAA [LAA velocity-SR vs. AF: 61 ± 22 vs. 29 ± 18 m/sec (p vs. AF: 46 ± 20 vs. 19 ± 8 m/sec (p brain natriuretic peptide (BNP). AF was associated with decreased RAA and LAA flow velocities. RAA velocity was found to be positively correlated with LAA velocity and negatively correlated with BNP. The plasma BNP concentration may serve as a determinant of LAA and RAA functions.

  1. Study of rNIS as a reporter gene monitoring rBMSC transplanted to rat myocardium

    International Nuclear Information System (INIS)

    Hu Shou; Lan Xiaoli; Cao Wei; Cao Guoxiang; Zhang Guopeng; Zhang Binqing; Wu Tao; Chang Wei; Zhang Yongxue

    2010-01-01

    Objective: To investigate the feasibility of rat sodium/iodide symporter (rNIS) as a reporter gene monitoring rat bone marrow mesenchymal cells (rBMSC) transplanted to rat myocardium in vivo. Methods: Recombinated adenovirus vector was constructed by rNIS/enhanced green fluorescence protein (EGFP) (Ad-rNIS/EGFP). rBMSC transfected by Ad-rNIS/EGFP were studied using fluorescence microscope. Fifteen rats were transplanted with rBMSC and randomly divided into three groups: rNIS group (with rNIS transfection), blocked group (with rNIS transfection) by oral intake of perchloric sodium before planar imaging (GE Millennium MPR SPECT), and control group (without rNIS transfection). All rats underwent 99 Tc m -pertechnetate planar imaging. The biological distribution of 99 Tc m -pertechnetate was studied. The expressions of rNIS gene and protein in myocardium were measured by real time polymerase chain reaction (PCR) and western blot, respectively. The expressions of CD 29 , CD 44 , CD 90 , CD 11 b, CD 34 and CD 45 were measured by immunohistochemistry. Results: rBMSC transfected by Ad-rNIS/EGFP showed EGFP expression under fluorescence microscope. The transplanted rat myocardium could be visualized on 99 Tc m -pertechnetate planar imaging in rNIS group. The relative uptake ratio (R heart /R hmb , RUR) was 6.7 ±0.4. RUR in control group (3.0 ±0.2) was lower than that in rNIS group (t =2.78, P=0.03). The percentage injection dose per gram of tissue (% ID/g) of the transplanted myocardium was 60.2 ± 20.8 in rNIS group, which was higher than that (2.5 ± 0.4) % ID/g of control group ( t = 7.13, P 29 , CD 44 and CD 90 were positive, CD 45 and CD 45 negative CD 11 b mildly positive in the myocardium transplanted with infective rBMSC. Conclusion: rNIS can efficiently monitor rBMSC transplanted to rat myocardium. (authors)

  2. Dabigatran use in Danish atrial fibrillation patients in 2011

    DEFF Research Database (Denmark)

    Sørensen, Rikke; Gislason, Gunnar; Torp-Pedersen, Christian Tobias

    2013-01-01

    Objective: Dabigatran was recently approved for anticoagulation in patients with atrial fibrillation (AF); data regarding real-world use, comparative effectiveness and safety are sparse. Design: Pharmacoepidemiological cohort study. Methods/settings: From nationwide registers, we identified...

  3. Women Sex Importance in Stroke Patients with Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Cemile Handan Mısırlı

    2014-08-01

    Full Text Available OBJECTIVE: It was shown the differences in age, risk factors and treatment between women and men in stroke patients with atrial fibrillation METHODS: The stroke patients with atrial fibrillation who were hospitalized in our department at the last 2 years were seperated into 2 groups of aged above 75 and below 75, investigated with CHADS2 and CHA2DS2VASc scores and looked at the sex differences of women and men. RESULTS: Stroke ratio according to sex was statistically meaningful especially in women above the age of 75. Risc factors also were founded in elderly women and CHA2DS2VASc scores were higher in women than men so more anticoagulan treatment were begun. No differences were shown between sexes at lone atrial fibrillation and no treatment were begun. CONCLUSION: Women with atrial fibrillation had more risk factors, higher stroke rate and higher anticoagulation treatment.

  4. Atrial fibrillation in the dog: a review of eight cases

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, R. E. [Vet. Hospital, 34 New Dover Rd, Canterbury, Kent (United Kingdom)

    1984-07-01

    Eight cases of canine atrial fibrillation encountered in small animal practice are reported. Details are included of age, sex and breed, history and clinical signs, thoracic radiography, electrocardiography, clinical pathology, treatment and survival periods.

  5. Atrial fibrillation in the dog: a review of eight cases

    International Nuclear Information System (INIS)

    Thomas, R.E.

    1984-01-01

    Eight cases of canine atrial fibrillation encountered in small animal practice are reported. Details are included of age, sex and breed, history and clinical signs, thoracic radiography, electrocardiography, clinical pathology, treatment and survival periods

  6. Inflammation in the genesis and perpetuation of atrial fibrillation

    DEFF Research Database (Denmark)

    Engelmann, Mads D M; Svendsen, Jesper Hastrup

    2005-01-01

    The prevalence and persistence of atrial fibrillation (AF) and the relative inefficacy of the currently available pharmacotherapy requires development of new treatment strategies. Recent findings have suggested a mechanistic link between inflammatory processes and the development of AF...

  7. Long working hours as a risk factor for atrial fibrillation

    DEFF Research Database (Denmark)

    Kivimäki, Mika; Nyberg, Solja T.; Batty, G. David

    2017-01-01

    long hours (≤55 per week) and those working standard 35-40 h/week. Methods and results In this prospective multi-cohort study from the Individual-Participant-Data Meta-Analysis in Working Populations (IPD-Work) Consortium, the study population was 85 494 working men and women (mean age 43.4 years...... of atrial fibrillation (10-year cumulative incidence 12.4 per 1000). After adjustment for age, sex and socioeconomic status, individuals working long hours had a 1.4-fold increased risk of atrial fibrillation compared with those working standard hours (hazard ratio = 1.42, 95% CI= 1.13-1.80, P= 0......Aims Studies suggest that people who work long hours are at increased risk of stroke, but the association of long working hours with atrial fibrillation, the most common cardiac arrhythmia and a risk factor for stroke, is unknown. We examined the risk of atrial fibrillation in individuals working...

  8. Atrial electrogram interpretation improves after an innovative education program.

    Science.gov (United States)

    Preston, Julie L; Currey, Judy; Considine, Julie

    2015-01-01

    To avoid adverse patient outcomes from inappropriate treatment, it is recommended that an atrial electrogram (AEG) be recorded whenever atrial arrhythmias develop in patients after cardiac surgery. However, AEGs are not commonly performed because nurses lack knowledge about differentiating atrial rhythms on AEGs. To investigate whether completing a novel online evidence-based education program on interpreting AEGs would improve critical care nurses' AEG interpretation. Specialized critical care nurses were taught about obtaining and interpreting atrial rhythms on AEGs using a 42-minute online mini-movie. AEG interpretation was assessed pre and two and eight weeks post-intervention. AEG interpretation increased two weeks post intervention and was retained at eight weeks. Some participants used this newly acquired knowledge to interpret arrhythmias that were not taught during the education program. Accurate interpretation of AEGs is an easy skill for specialized critical care nurses to learn via an online education program.

  9. Paroxysmal atrial fibrillation occurs often in cryptogenic ischaemic stroke

    DEFF Research Database (Denmark)

    Christensen, L M; Krieger, D W; Højberg, S

    2014-01-01

    BACKGROUND AND PURPOSE: Atrial fibrillation (AF) increases the risk of stroke fourfold and is associated with a poor clinical outcome. Despite work-up in compliance with guidelines, up to one-third of patients have cryptogenic stroke (CS). The prevalence of asymptomatic paroxysmal atrial fibrilla......BACKGROUND AND PURPOSE: Atrial fibrillation (AF) increases the risk of stroke fourfold and is associated with a poor clinical outcome. Despite work-up in compliance with guidelines, up to one-third of patients have cryptogenic stroke (CS). The prevalence of asymptomatic paroxysmal atrial...... lasting predominantly between 1 and 4 h. Four recurrent strokes were observed, three in patients with PAF; all three patients were on oral anticoagulation (OAC). CONCLUSIONS: One in five patients with CS had PAF, which occurred at low burden and long after stroke. Future studies should determine the role...

  10. 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 ...

  11. Atrial angioleiomyoma with myopericytoma-like features: a case report.

    Science.gov (United States)

    Nassereddine, Hussein; Cazes, Aurélie; Verdonk, Constance; Assous, Benjamin; Dautry, Raphael; Nataf, Patrick; Wassef, Michel; Deschamps, Lydia

    A 66-year-old female patient was referred to our hospital for resection of a right atrial mass. Four months earlier, she had suffered an acute cerebrovascular accident due to occlusion of the sylvian segment of the right middle cerebral artery from atheromatous tight stenosis in the right internal carotid artery. Later, investigations with transthoracic and transesophageal echocardiography revealed a 3.4-cm right atrial mass that was resected surgically. Microscopic evaluation revealed a well-circumscribed nodular tumor, located within the interatrial septum, and corresponding to an angioleiomyoma (ALM). This tumor differs histologically from atrial myxoma. ALM is a ubiquitous benign tumor but has never been reported to occur in the atrium. ALM can mimic cardiac myxoma and should be considered in the differential diagnosis of atrial tumors. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Self-expanding nanoplatinum-coated nitinol devices for atrial septal defect and patent ductus arteriosus closure: a swine model.

    Science.gov (United States)

    Lertsapcharoen, Pornthep; Khongphatthanayothin, Apichai; La-orkhun, Vidhavas; Supachokchaiwattana, Pentip; Charoonrut, Phingphol

    2006-01-01

    Our purpose was to evaluate self-expanding nanoplatinum-coated nitinol devices for transcatheter closure of atrial septal defects and patent ductus arteriosus in a swine model. The devices were braided from platinum-activated nitinol wires and filled with polyester to enhance thrombogenicity. The platinum activation of the nitinol wires was carried out with the help of Nanofusion technology. The coating of platinum covers the exposed surface of the nitinol wires and prevents the release of nickel into the blood stream after the implantation of the device but does not affect its shape memory, which makes the device self-expanding after it is loaded from the catheter. Atrial septal defects were created in 12 piglets by balloon dilation of the patent foramen ovale. The size of the device was selected on the basis of the diameter of the balloon and the size of the defect, measured by transthoracic echocardiography. The devices were successfully deployed in all 12 piglets under fluoroscopic study. Transthoracic color Doppler echocardiograms showed complete closure of the atrial septal defect within 15 minutes of device implantation. Twelve patent ductus arteriosus closure devices were deployed in the right or left subclavian arteries in 10 piglets. Angiograms showed complete occlusion of the subclavian arteries within a few minutes of device deployment. In the atrial septal defect cases, the autopsy findings showed complete organizing fibrin thrombus formation and complete neo-endothelialization on the outer surface of the devices within one week and six weeks of implantation, respectively. The use of self-expanding nanoplatinum-coated nitinol devices for the transcatheter closure of atrial septal defects and patent ductus arteriosus is feasible. The excellent occlusion result and complete neo-endothelialization of the devices in the swine model is an indication of the potential of these devices in human application.

  13. [Left atrial function and left atrial appendage flow velocity in hypertrophic cardiomyopathy: comparison of patients with and without paroxysmal atrial fibrillation].

    Science.gov (United States)

    Akasaka, K; Kawashima, E; Shiokoshi, T; Ishii, Y; Hasebe, N; Kikuchi, K

    1998-07-01

    The involvement of left atrial (LA) appendage flow velocity in reduced left atrial function was investigated in 24 patients with hypertrophic cardiomyopathy, who retained sinus rhythm at the examination. Patients were divided into 11 with a history of paroxysmal atrial fibrillation [PAf(+)] and 13 without such history [PAf(-)]. Transthoracic echocardiography was performed to evaluate LA fractional shortening (LA%FS) and mean velocity of circumferential LA fiber shortening (LAmVcf), as contractile functions of the left atrium at the phase of active atrial contraction. Transesophageal echocardiographic Doppler examination was performed in all patients to measure the LA appendage velocity. In all patients, significant positive correlations were observed between the LA appendage velocity and LA%FS (r = 0.50, p fibrillation were significantly lower than in those without (0.84 +/- 0.15 vs 1.28 +/- 0.37 circ/sec, 44 +/- 12 vs 65 +/- 20 cm/sec, both p fibrillation. These results indicate that there is a close relationship between LA appendage velocity and LA contractile function in patients with hypertrophic cardiomyopathy with paroxysmal atrial fibrilation, and these patients have potential risk of cerebral infarction.

  14. Stroke and bleeding in atrial fibrillation with chronic kidney disease

    DEFF Research Database (Denmark)

    Olesen, Jonas Bjerring; Lip, Gregory Y.H.; Kamper, Anne-Lise

    2012-01-01

    Both atrial fibrillation and chronic kidney disease increase the risk of stroke and systemic thromboembolism. However, these risks, and the effects of antithrombotic treatment, have not been thoroughly investigated in patients with both conditions.......Both atrial fibrillation and chronic kidney disease increase the risk of stroke and systemic thromboembolism. However, these risks, and the effects of antithrombotic treatment, have not been thoroughly investigated in patients with both conditions....

  15. Three-dimensional transesophageal echocardiography of the atrial septal defects

    Directory of Open Access Journals (Sweden)

    Romero-Cárdenas Ángel

    2008-07-01

    Full Text Available Abstract Transesophageal echocardiography has advantages over transthoracic technique in defining morphology of atrial structures. Even though real time three-dimensional echocardiographic imaging is a reality, the off-line reconstruction technique usually allows to obtain higher spatial resolution images. The purpose of this study was to explore the accuracy of off-line three-dimensional transesophageal echocardiography in a spectrum of atrial septal defects by comparing them with representative anatomic specimens.

  16. Aorto-right atrial fistula after Bentall repair.

    Science.gov (United States)

    Howard, Charles E; Velasco, Carlos E; Roullard, Christina P; Rafael, Aldo

    2017-07-01

    We describe a man with the Marfan syndrome and a prior ascending aortic aneurysm resection who presented with knee pain and concern of endocarditis. Transesophageal echocardiogram showed no vegetations, and computed tomography angiogram of the heart showed a possible pseudoaneurysm. Cardiac catheterization and aortogram revealed the diagnosis of an aorto-right atrial fistula, which was then operatively repaired. This case highlights the role that cardiac catheterization with aortogram can play in the detection of aorto-atrial fistula.

  17. Vernakalant hydrochloride for the treatment of atrial fibrillation.

    Science.gov (United States)

    Kozlowski, Dariusz; Budrejko, Szymon; Lip, Gregory Y H; Mikhailidis, Dimitri P; Rysz, Jacek; Raczak, Grzegorz; Banach, Maciej

    2009-12-01

    Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Rhythm control strategy for AF is limited by drug toxicity and side effects, and recent trials have shown that this strategy is not superior to a rate control one. New antiarrhythmic drugs, free of undesired effects, would enhance rhythm control, with the possibility of sinus rhythm restoration and maintenance. A promising find in the search for new antiarrhythmic therapies is atrial-tissue specific ion channels. The findings that the ultrarapid delayed rectifier (I(Kur)) and the inwardly rectifying, acetylcholine-regulated current (I(K-Ach)) exist in atrial but not ventricular tissue increase the probability that atrioselective drugs without ventricular proarrhythmic toxicity can be developed for treatment of patients with AF. There are also other potential targets for atrial-selective therapy: transient outward current (I(to)), rapidly and slowly activating delayed rectifier currents (I(Kr) and I(Ks)), atrial sodium current (I(Na)) and atrially expressed connexins. New drugs under development with promising atrial-selectivity include: tertiapin, NIP-142, NIP-141, JTV-519, AVE0118, AVE1231, DPO-1, AZD7009 and many others. Among such new agents, vernakalant hydrochloride is currently in an advanced phase of development and has already been evaluated in clinical trials. In this overview, we describe the history and current state of developmental process of the drug, as well as its mechanism of action and influence on electrophysiological parameters. Vernakalant seems to be effective in terminating recent-onset AF, but is not efficacious in long-lasting AF and atrial flutter. The drug may be relatively free of proarrhythmic effects, and exerts a protective effect on ventricular tissue and ventricular repolarization. It is expected that the intravenous formulation will soon be approved for the pharmacological termination of recent-onset AF.

  18. Nephroblastoma with right atrial extension: preoperative diagnosis and management.

    Science.gov (United States)

    Vaughan, E D; Crosby, I K; Tegtmeyer, C J

    1977-04-01

    A 14-year-old black boy, with a large nephroblastoma of the right kidney, had preoperative identification of inferior vena cava and right atrial involvement. Renal arteriography revealed linear arterial channels in the anatomic distribution of the inferior vena cava and venography revealed total caval occlusion and a right atrial mass. Radical excision, using a cardiopulmonary bypass, resulted in a 6-month postoperative survival.

  19. A new therapeutic strategy for electrical cardioversion of atrial fibrillation.

    Science.gov (United States)

    de Luca, I; Sorino, M; Del Salvatore, B; de Luca, L

    2001-11-01

    The conventional approach to cardioversion of atrial fibrillation includes a period of anticoagulation with oral anticoagulant therapy (OAT) extending from 3 weeks precardioversion to 4 weeks postcardioversion. The protocol of rapid anticoagulation (such as that of the ACUT