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Sample records for atrial appendage flow

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

    SciTech Connect

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

    1996-06-01

    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 ({ital f{sub 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 {ital f{sub 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 {ital f{sub 1}, f{sub 2}}, and other peak frequencies as linear combinations thereof ({ital mf{sub 1}{+-}nf{sub 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.

  2. Left Atrial Appendage Exclusion for Atrial Fibrillation

    PubMed Central

    Syed, Faisal F.; DeSimone, Christopher V.; Friedman, Paul A.; Asirvatham, Samuel J.

    2015-01-01

    SYNOPSIS Percutaneous left atrial appendage (LAA) closure is increasingly being used as a treatment strategy to prevent stroke in patients with atrial fibrillation (AF) who have contraindications to anticoagulants. A number of approaches and devices have been developed in the last few years, each with their own unique set of advantages and disadvantages. We review the published studies on surgical and percutaneous approaches to LAA closure; focusing on stroke mechanisms in AF, LAA structure and function relevant to stroke prevention, practical differences in procedural approach, and clinical considerations surrounding management. PMID:25443240

  3. Left Atrial Appendage Closure Devices

    PubMed Central

    Romero, Jorge; Perez, Irving E; Krumerman, Andrew; Garcia, Mario J; Lucariello, Richard J

    2014-01-01

    Atrial fibrillation (AF) increases the risk for thromboembolic stroke five-fold. The left atrial appendage (LAA) has been shown to be the main source of thrombus formation in the majority of strokes associated with AF. Oral anticoagulation with warfarin and novel anticoagulants remains the standard of care; however, it has several limitations, including bleeding and poor compliance. Occlusion of the LAA has been shown to be an alternative therapeutic approach to drug therapy. The purpose of this article is to review the different techniques and devices that have emerged for the purpose of occluding this structure, with a particular emphasis on the efficacy and safety studies published to date in the medical literature. PMID:24963274

  4. Aneurysm of the Left Atrial Appendage

    PubMed Central

    Victor, Solomon; Nayak, Vijaya M.

    2001-01-01

    A 43-year-old woman underwent excision of an aneurysm of the left atrial appendage, which had been causing cerebrovascular embolic episodes. We attribute the aneurysm to congenital dysplasia of the musculi pectinati in the left atrial appendage and of the bands of atrial muscle from which they arise. In Appendix I, we draw attention to the morphologically similar arrangements of inner and outer bands that emanate from a common transverse interatrial band and yield morphologically similar medial, descending, and ascending palm-leaf arrangements of musculi pectinati. In addition, we observe that the strap-like arrangements of musculi in both atria connect the outer band with the para-annular segment of the inner band. In Appendix II, we briefly review the literature concerning musculi pectinati and related bands. PMID:11453121

  5. Assessment of left atrial appendage flow velocity and its relation to spontaneous echocardiographic contrast in 89 cats with myocardial disease.

    PubMed

    Schober, Karsten E; Maerz, Imke

    2006-01-01

    The hypotheses of this prospective study were that (1) left atrial appendage (LAA) blood flow velocities can be recorded in cats with myocardial disease by transthoracic Doppler echocardiography, (2) LA enlargement, LA mechanical dysfunction, and left ventricular (LV) diastolic abnormalities are associated with decreased LAA flow velocities, and (3) low LAA flow velocities predict the appearance of spontaneous echocardiographic contrast in cats with cardiomyopathy. Transthoracic 2-dimensional, M-mode, and Doppler echocardiographic studies were performed in 89 cats with hypertrophic, restrictive, dilated, or unclassified cardiomyopathy or with hyperthyroid heart disease. Maximal LAA flow velocity (LAAmax) was decreased (P < .001) in cats with cardiomyopathy (median, 0.28 m/s; range, 0.08-1.35) compared to normal cats. Associated with decreased LAA flow velocities were increased LA size, decreased LA function, increased severity of LV diastolic dysfunction, and the presence of congestive heart failure. Multivariate logistic regression analysis detected an LAAmax <0.20 m/s as the only independent variable to predict LA spontaneous echocardiographic contrast (odds ratio, 30.1; 95% confidence interval [CI], 4.1 222.3; P < .001). Receiver operating characteristic analysis performed to predict spontaneous echocardiographic contrast indicated an area under the curve of 0.88 (95% CI, 0.80-0.95; P < .001) with sensitivities of 100 and 74% and specificities of 69 and 83% for LAAmax <0.25 and <0.20 m/s, respectively. Thus, low LAA flow velocities identified a subgroup of patients at increased risk of spontaneous echocardiographic contrast and possible thromboembolism. These findings may have important clinical implications for anticoagulation therapy and prognostication in cats with cardiomyopathy.

  6. Juxtaposed atrial appendages: A curiosity with some clinical relevance

    PubMed Central

    Singhi, Anil Kumar; Pradhan, Priya; Agarwal, Ravi; Sivakumar, Kothandum

    2016-01-01

    If the atrial appendages lie adjacent to each other on same side of the great arteries, instead of encircling their roots, they are referred as juxtaposed. Right juxtaposition of atrial appendages is less common than left juxtaposition. The images demonstrate the classical radiological, echocardiographic, and surgical images of juxtaposed atrial appendages. Their clinical incidence, associations, and relevance during interventional and surgical procedures are discussed. PMID:27212860

  7. Left atrial appendage mass: is it always a thrombus?

    PubMed Central

    Guler, Adem; Kurkluoglu, Mustafa; Yesil, Fahri Gurkan; Tavlasoglu, Murat; Cingoz, Faruk

    2016-01-01

    Myxoma is the most common benign tumor of the heart, but it is very rare for it to originate from the left atrial appendage. Distinguishing between a mass, a thrombus, and a tumor in the body of the left atrium with preoperative transthoracic or transesophageal echocardiography is very difficult, even more so in patients with mitral valve disease and chronic atrial fibrillation. A 50-year-old male patient was admitted for surgery with the diagnosis of mitral stenosis and chronic atrial fibrillation. Transesophageal echocardiography demonstrated a mass attached to the wall of the left atrial appendage. Histopathological examination of the mass showed an image compatible with a myxoma. We hereby describe a case of a left atrial appendage myxoma mimicking a left atrial appendage thrombus. PMID:28096835

  8. Right atrial tunnel to the left atrial appendage: a danger during balloon septostomy.

    PubMed

    Waldman, J D; McFeeley, P; Bornikova, L

    2001-01-01

    Right atrial tunnel to the left atrial appendage is a very rare anomaly not previously described. Per se, it has no physiological significance but is a source of potential disaster during balloon atrial septostomy. The precise anatomy is demonstrated and ways are proposed to avoid tearing the atrial wall during therapeutic cardiac catheterization.

  9. [Prophylaxis of thromboembolism in atrial fibrillation: new oral anticoagulants and left atrial appendage closure].

    PubMed

    Zeus, Tobias; Kelm, Malte; Bode, Christoph

    2015-08-01

    Thrombo-embolic prophylaxis is a key element within the therapy of atrial fibrillation/atrial flutter. Besides new oral anticoagulants the concept of left atrial appendage occlusion has approved to be a good alternative option, especially in patients with increased risk of bleeding.

  10. Left atrial appendage occlusion: A better alternative to anticoagulation?

    PubMed Central

    Akin, Ibrahim; Nienaber, Christoph A

    2017-01-01

    Non-valvular atrial fibrillation is associated with a significantly increased risk of embolic stroke due to blood clot forming predominantly in the left atrial appendage (LAA). Preventive measures to avoid embolic events are permanent administration of anticoagulants or surgical closure of the LAA. Various clinical trials provide evidence about safety, effectiveness and therapeutic success of LAA occlusion using various cardiac occluder devices. The use of such implants for interventional closure of the LAA is likely to become a valuable alternative for stroke prevention, especially in patients with contraindication for oral anticoagulation as safety, clinical benefit and cost-effectiveness of LAA occlusion has recently been demonstrated. PMID:28289527

  11. Possible role for cryoballoon ablation of right atrial appendage tachycardia when conventional ablation fails.

    PubMed

    Amasyali, Basri; Kilic, Ayhan

    2015-06-01

    Focal atrial tachycardia arising from the right atrial appendage usually responds well to radiofrequency ablation; however, successful ablation in this anatomic region can be challenging. Surgical excision of the right atrial appendage has sometimes been necessary to eliminate the tachycardia and prevent or reverse the resultant cardiomyopathy. We report the case of a 48-year-old man who had right atrial appendage tachycardia resistant to multiple attempts at ablation with use of conventional radiofrequency energy guided by means of a 3-dimensional mapping system. The condition led to cardiomyopathy in 3 months. The arrhythmia was successfully ablated with use of a 28-mm cryoballoon catheter that had originally been developed for catheter ablation of paroxysmal atrial fibrillation. To our knowledge, this is the first report of cryoballoon ablation without isolation of the right atrial appendage. It might also be an alternative to epicardial ablation or surgery when refractory atrial tachycardia originates from the right atrial appendage.

  12. Percutaneous closure of a left atrial appendage with relevant suture dehiscence.

    PubMed

    Kleinebrecht, L; Veulemans, V; Polzin, A; Kelm, M; Zeus, T

    2017-02-01

    Atrial fibrillation is a widespread disease and highly relevant as it carries an extended risk for ischaemic stroke. Surgical closure of the left atrial appendage is routinely performed during open heart surgery in patients with atrial fibrillation with the aim of thromboembolic protection. In this report we present a successful percutaneous closure of a left atrial appendage, which showed clinically relevant suture dehiscence several years after surgical closure.

  13. Enlargement of the Excluded Left Atrial Appendage With Thrombus.

    PubMed

    Aoyagi, Shigeaki; Tobinaga, Satoru; Saisho, Hiroyuki

    2017-02-07

    We report progressive enlargement of the excluded left atrial appendage (LAA) with a thrombus in a patient who had undergone valve surgery and endocardial suture closure of the LAA previously. Echocardiography and CT detected no communication between the LAA and the left atrium. Magnetic resonance imaging showed the LAA was filled with fresh and old thrombi. Coronary arteriography demonstrated small left coronary artery-LAA fistulae. At surgery, successful exclusion of the LAA was confirmed after removal of the thrombi. Persistent inflow of blood through the coronary artery fistulae to the excluded LAA may be the primary mechanism of this pathology.

  14. Left Atrial Appendage Ligation and Exclusion Technology in the Incubator

    PubMed Central

    Syed, Faisal F.; Noheria, Amit; DeSimone, Christopher V.; Asirvatham, Samuel J.

    2016-01-01

    Stroke is the most feared complication of atrial fibrillation (AF). Targeting the left atrial appendage (LAA) mechanically is attractive as a means to simultaneously reduce stroke risk, the need for anticoagulation, and hemorrhagic complications in patients with non-valvular AF. The results of the PROTECT-AF and PREVAIL randomized clinical trials support this approach as a viable therapeutic alternative to warfarin in selected patients and add to accumulating evidence regarding the importance of the LAA in thromboembolism in AF. A number of devices for percutaneous LAA closure are under investigation or development. In this article, key design features of these ligation and exclusion technologies will be discussed, with a focus on aspects of LAA morphology, relational anatomy, thrombosis, and thromboembolism relevant for successful device development and deployment. PMID:27087888

  15. Is percutaneous closure of the left atrial appendage comparable to anticoagulants for atrial fibrillation?

    PubMed

    Uslar, Thomas; Anabalón, Jaime

    2015-08-17

    For most atrial fibrillation patients oral anticoagulation constitutes the standard treatment to prevent stroke. However, they carry a risk of bleeding, which is why alternative treatments have been put into practice, such as percutaneous closure of the left atrial appendage. It is not clear whether this is as effective as the conventional treatment with anticoagulants. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified three systematic reviews including only one pertinent randomized controlled trial. We combined the evidence and generated a summary of findings following the GRADE approach. We concluded that percutaneous left atrial appendage occlusion may decrease stroke and mortality, but the certainty of the evidence is low. The effect on other outcomes is not clear because the certainty of the evidence is very low.

  16. Partial left pericardial defect with herniation of the left atrial appendage

    PubMed Central

    Pernot, C.; Hoeffel, J C.; Henry, M.; Frisch, R.; Brauer, B.

    1972-01-01

    A case is reported of herniation of the left atrial appendage through a partial pericardial defect, probably congenital. The diagnosis was suggested by the history of chest pain and bulging of the middle segment of the left heart border on the plain chest film, without other signs. Angiography revealed a dilated left atrial appendage. An artificial left pneumothorax confirmed the presence of a pleuropericardial defect. The surgical procedure included excision of the appendage and closure of the defect. Images PMID:5034603

  17. Structural Comparison between the Right and Left Atrial Appendages Using Multidetector Computed Tomography

    PubMed Central

    Shinoda, Koichi; Fukuoka, Daisuke; Torii, Ryo; Watanabe, Tsuneo; Nakano, Takashi

    2016-01-01

    The three-dimensional (3D) structures of the right atrial appendage (RAA) and left atrial appendage (LAA) were compared to clarify why thrombus formation less frequently occurs in RAA than in LAA. Morphological differences between RAA and LAA of 34 formalin-preserved cadaver hearts were investigated. Molds of RAA and LAA specimens were made and the neck areas, volumes of the atrial appendages (AA), and amount of pectinate muscles (PMs) were analyzed using multidetector computed tomography. In RAA, most PMs were connected to one another and formed a “dendritic” appearance and the inner surface area was smaller than in LAA. RAA had smaller volumes and larger neck areas than LAA. The ratios of the neck area/volume were larger and the amounts of PMs were smaller in RAA than in LAA. The volumes, neck areas, and amount of PMs of RAA were significantly correlated with those of LAA. According to the 3D structure, RAA appears to be suited for a more favorable blood flow, which may explain why the thrombus formation is less common in RAA than in LAA. Examining not only LAA but also RAA by transesophageal echocardiography may be useful in high-risk patients of thrombus formation in LAA because the volume, neck area, and amount of PMs of LAA reflect the shape of RAA. PMID:27900330

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

    PubMed

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

    2012-02-01

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

  19. Percutaneous epicardial ablation of incessant atrial tachycardia originating from the left atrial appendage

    PubMed Central

    Ban, Ji-Eun; Park, Tae Young

    2016-01-01

    A 38-year-old woman presented with antiarrhythmic drug-refractory atrial tachycardia (AT). Holter recording demonstrated incessant episodes of AT followed by a long sinus pause. Electrophysiologic study revealed that the earliest endocardial activation was observed at the neck of the left atrial appendage (LAA). After unsuccessful endocardial ablation, epicardial access via a percutaneous subxiphoid approach demonstrated that the earliest epicardial atrial activation was observed on the opposite site to the endocardial LAA neck suggestive of ligament of Marshall (LOM) muscle sleeve as regarding the epicardial sharp potentials under guidance of a circular mapping catheter. Application of radiofrequency (RF) energy at this site terminated the tachycardia. After tachycardia ablation, the sinus pause also resolved. PMID:28066659

  20. Relationship between body mass index and left atrial appendage thrombus in nonvalvular atrial fibrillation.

    PubMed

    Cohoon, Kevin P; McBane, Robert D; Ammash, Naser; Slusser, Joshua P; Grill, Diane E; Wysokinski, Waldemar E

    2016-05-01

    Atrial fibrillation and obesity are two major growing epidemics in the United States and globally. Obese people are at the increased risk of developing atrial fibrillation. The contribution of obesity as an independent risk factor for stroke in the setting of atrial fibrillation remains unclear. We tested the hypothesis that non-valvular atrial fibrillation (NVAF) patients with increased body mass index (BMI) would be at increased risk for the development of left atrial appendage thrombus (LAAT). Consecutive, anticoagulation naïve patients with NVAF referred for a transesophageal echocardiogram (TEE) between January 1, 2007 and October 21, 2009 were approached for study participation. All clinical, laboratory, and TEE measurement data were collected prospectively. Within a group of 400 anticoagulation naïve NVAF patients (mean age 63 ± 15 years, 28 % women; 17 % with LAAT) the prevalence of LAAT was similar across all BMI categories (normal 13 %, overweight 19 %, obese 16 %, morbidly obese 16 %; p = 0.71). Despite a higher CHADS2 score and a higher prevalence of both hypertension and diabetes mellitus, elevated BMI was not an independent predictor of LAAT when analyzed as either a continuous variable, across BMI WHO categories, a dichotomous variable stratified at values above versus below 27 kg/m(2), or BMI stratified on atrial fibrillation duration. Despite a higher prevalence of major risk factors for thromboembolism, the prevalence of LAAT was not increased in overweight, obese, and morbidly obese patients.

  1. Inferior and right-sided juxtaposition of the left atrial appendage with an unexpected type of inter-atrial communication.

    PubMed

    Sarwark, Anne E; Anderson, Robert H; Spicer, Diane E

    2016-01-01

    We have re-investigated an unusual cardiac specimen with juxtaposition of the atrial appendages. The original description dates to 1962, when the autopsy was performed at the Children's Memorial Hospital in Chicago, now Ann & Robert H. Lurie Children's Hospital of Chicago. The heart was subsequently stored in the Farouk S. Idriss Cardiac Registry at the same institution. The specimen shows usual atrial arrangement, but with the morphologically left appendage juxtaposed in a rightward manner, passing behind the heart rather than through the transverse sinus so as to reach its location inferior to the morphologically right appendage. The heart also demonstrated an inter-atrial communication between the cavities of the juxtaposed left appendage and the morphologically right atrium. We provide a detailed description of the morphology, and provide images of this lesion, which to the best of our knowledge has not previously been described.

  2. Role of Endovascular Closure of the Left Atrial Appendage in Stroke Prevention for Atrial Fibrillation.

    PubMed

    Kiani, Jawad; Holmes, David R

    2015-11-01

    The pathophysiologic mechanism of thromboembolic stroke in the setting of non-valvular atrial fibrillation (AF) resides in the left atrial appendage (LAA). In this setting, approximately 90 % of all strokes originate from this structure. Percutaneous left atrial appendage occlusion (LAAO) therapy has recently emerged as an important strategy for prevention of stroke and systemic embolism in patients with non-valvular AF. Systemic anticoagulation therapy in this AF population, while effective, is associated with a significant bleeding risk, drug compliance issues, and limited reversal strategies. In this manuscript, we will review the percutaneous devices and techniques that allow endovascular closure of the LAA, including their efficacy in stroke prevention, the safety profile of these local site-specific therapies, comparison of the multiple approaches being studied, the index patient populations involved, and long-term follow-up in comparison with systemic anticoagulation therapy. The percutaneous LAAO approach indeed represents an exciting and revolutionary advance in the field of stroke prevention in AF.

  3. Left Atrial Appendage Closure in Atrial Fibrillation: A World without Anticoagulation?

    PubMed

    Contractor, Tahmeed; Khasnis, Atul

    2011-03-30

    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.

  4. Percutaneous Closure of the Left Atrial Appendage in Atrial Fibrillation, Second Thoughts?

    PubMed Central

    Wagdi, Philipp; Salzer, Frank

    2012-01-01

    Life expectancy of the population is steadily increasing world wide. Consequently, the incidence and ultimately the prevalence of atrial fibrillation (AF) and it’s sequelae will be rising proportionately. It is estimated that 3-5% of persons above 65 years of age have chronic AF, 30% of which will suffer at least one stroke. On the other hand, chronic AF is responsible for about 20% of all cerebrovascular accidents. Predictors of stroke in AF have been defined by the CHADS2 score, and in these patients, oral anticoagulation has been the cornerstone of thromboembolic disease prevention. Because elderly patients have an increased risk of bleeding complications even under the newer antagonists of Factor Xa and direct Thrombin inhibitors, percutaneous occlusion of the left atrial appendage (LAA) as the main thrombogenic source offers an attractive alternative to permanent anticoagulation. This promising new therapeutic approach is put into clinical real world perspective.

  5. Left atrial appendage occlusion with the WATCHMAN™ for stroke prevention in atrial fibrillation.

    PubMed

    Price, Matthew J

    2014-01-01

    Atrial fibrillation (AF) is a major cause of stroke and systemic embolism. Although warfarin and the novel oral anticoagulants reduce thromboembolic risk, they are associated with an ongoing bleeding hazard, in addition to other limitations that deter their use. The left atrial appendage (LAA) appears to be the primary source of thrombus in AF; therefore, LAA closure represents a mechanical strategy for stroke prevention in these patients. The WATCHMAN™ LAA closure device (Boston Scientific, Natick, MA) is a nitinol-framed occluder that is implanted percutaneously under echocardiographic and fluoroscopic guidance. Data from two randomized clinical trials support the clinical efficacy of transcatheter LAA occlusion with the WATCHMAN and demonstrate that procedural safety has improved significantly since initial experience. This article summarizes the rationale, procedural technique, safety, and clinical efficacy of the WATCHMAN device in patients with AF at high risk for thromboembolic events.

  6. Left atrial appendage exclusion for prevention of stroke in atrial fibrillation: review of minimally invasive approaches.

    PubMed

    Moss, Joshua D

    2014-02-01

    Stroke prevention is of vital importance in the management of atrial fibrillation (AF), though the proven strategy of systemic anticoagulation for thromboembolic prophylaxis is underutilized for a variety of reasons. The left atrial appendage (LAA) has long been suspected as the principal source of arterial emboli, particularly in nonvalvular AF, and a variety of techniques for its exclusion from the circulation have been developed. This review highlights the history of the LAA as a target of intervention, and the parallel advances in three minimally invasive strategies for its exclusion: percutaneous occlusion of the LAA orifice from within the left atrium, closed-chest ligation via a percutaneous pericardial approach, and minimally invasive thoracoscopic surgery. While further study is necessary, available evidence suggests that effective LAA exclusion is becoming a viable alternative to anticoagulation for stroke prevention in nonvalvular AF.

  7. Imaging Techniques in Percutaneous Cardiac Structural Interventions: Atrial Septal Defect Closure and Left Atrial Appendage Occlusion.

    PubMed

    Rodríguez Fernández, Antonio; Bethencourt González, Armando

    2016-08-01

    Because of advances in cardiac structural interventional procedures, imaging techniques are playing an increasingly important role. Imaging studies show sufficient anatomic detail of the heart structure to achieve an excellent outcome in interventional procedures. Up to 98% of atrial septal defects at the ostium secundum can be closed successfully with a percutaneous procedure. Candidates for this type of procedure can be identified through a systematic assessment of atrial septum anatomy, locating and measuring the size and shape of all defects, their rims, and the degree and direction of shunting. Three dimensional echocardiography has significantly improved anatomic assessments and the end result itself. In the future, when combined with other imaging techniques such as cardiac computed tomography and fluoroscopy, 3-dimensional echocardiography will be particularly useful for procedure guidance. Percutaneous closure of the left atrial appendage offers an alternative for treating patients with atrial fibrillation and contraindication for oral anticoagulants. In the future, the clinical focus may well turn to stroke prevention in selected patients. Percutaneous closure is effective and safe; device implantation is successful in 94% to 99% of procedures. However, the procedure requires an experienced cardiac structural interventional team. At present, 3-dimensional echocardiography is the most appropriate imaging technique to assess anatomy suitability, select device type and size, guide the procedure alongside fluoroscopy, and to follow-up the patient afterwards.

  8. Efficacy of anticoagulation in resolving left atrial and left atrial appendage thrombi: A transesophageal echocardiographic study

    NASA Technical Reports Server (NTRS)

    Jaber, W. A.; Prior, D. L.; Thamilarasan, M.; Grimm, R. A.; Thomas, J. D.; Klein, A. L.; Asher, C. R.

    2000-01-01

    BACKGROUND: Transesophageal echocardiography (TEE) is the gold standard for evaluation of the left atrium and the left atrial appendage (LAA) for the presence of thrombi. Anticoagulation is conventionally used for patients with atrial fibrillation to prevent embolization of atrial thrombi. The mechanism of benefit and effectiveness of thrombi resolution with anticoagulation is not well defined. METHODS AND RESULTS: We used a TEE database of 9058 consecutive studies performed between January 1996 and November 1998 to identify all patients with thrombi reported in the left atrium and/or LAA. One hundred seventy-four patients with thrombi in the left atrial cavity (LAC) and LAA were identified (1.9% of transesophageal studies performed). The incidence of LAA thrombi was 6.6 times higher than LAC thrombi (151 vs 23, respectively). Almost all LAC thrombi were visualized on transthoracic echocardiography (90.5%). Mitral valve pathology was associated with LAC location of thrombi (P <.0001), whereas atrial fibrillation or flutter was present in most patients with LAA location of thrombi. Anticoagulation of 47 +/- 18 days was associated with thrombus resolution in 80.1% of the patients on follow-up TEE. Further anticoagulation resulted in limited additional benefit. CONCLUSIONS: LAC thrombi are rare and are usually associated with mitral valve pathology. Transthoracic echocardiography is effective in identifying these thrombi. LAA thrombi occur predominantly in patients with atrial fibrillation or flutter. Short-term anticoagulation achieves a high rate of resolution of LAA and LAC thrombi but does not obviate the need for follow-up TEE.

  9. Imaging of thrombi and assessment of left atrial appendage function: a prospective study comparing transthoracic and transoesophageal echocardiography

    PubMed Central

    Omran, H; Jung, W; Rabahieh, R; Wirtz, P; Becher, H; Illien, S; Schimpf, R; Luderitz, B

    1999-01-01

    Objective—To compare the value of current transthoracic echocardiographic systems and transoesophageal echocardiography for assessing left atrial appendage function and imaging thrombi.
Design—Single blind prospective study. Patients were first investigated by transthoracic echocardiography and thereafter by a second investigator using transoesophageal echocardiography. The feasibility of imaging the left atrial appendage, recording its velocities, and identifying thrombi within the appendage were determined by both methods.
Patients—117 consecutive patients with a stroke or transient neurological deficit.
Setting—Tertiary cardiac and neurological care centre.
Results—Imaging of the complete appendage was feasible in 75% of the patients by transthoracic echocardiography and in 95% by transoesophageal echocardiography. Both methods were concordant for the detection of thrombi in 10 cases. Transoesophageal echocardiography revealed two additional thrombi. In one of these patients, transthoracic echocardiography was not feasible and in the other the thrombus had been missed by transthoracic examination. In patients with adequate transthoracic echogenicity, the specificity and sensitivity of detecting left atrial appendage thrombi were 100% and 91%, respectively. Recording of left atrial appendage velocities by transthoracic echocardiography was feasible in 69% of cases. None of the patients with a velocity > 0.3 m/s had left atrial appendage thrombi. In the one patient in whom transthoracic echocardiographic evaluation missed a left atrial appendage thrombus, the peak emptying velocity of the left atrial appendage was 0.25 m/s.
Conclusions—A new generation echocardiographic system allows for the transthoracic detection of left atrial appendage thrombi and accurate determination of left atrial appendage function in most patients with a neurological deficit.

 Keywords: echocardiography; left atrial appendage thrombi; stroke; thromboembolism

  10. Identifying Future Research Priorities Using Value of Information Analyses: Left Atrial Appendage Occlusion Devices in Atrial Fibrillation

    PubMed Central

    Micieli, Andrew; Bennell, Maria C.; Pham, Ba’; Krahn, Murray; Singh, Sheldon M.; Wijeysundera, Harindra C.

    2014-01-01

    Background Left atrial appendage occlusion devices are cost effective for stroke prophylaxis in atrial fibrillation when compared with dabigatran or warfarin. We illustrate the use of value‐of‐information analyses to quantify the degree and consequences of decisional uncertainty and to identify future research priorities. Methods and Results A microsimulation decision‐analytic model compared left atrial appendage occlusion devices to dabigatran or warfarin in atrial fibrillation. Probabilistic sensitivity analysis quantified the degree of parameter uncertainty. Expected value of perfect information analyses showed the consequences of this uncertainty. Expected value of partial perfect information analyses were done on sets of input parameters (cost, utilities, and probabilities) to identify the source of the greatest uncertainty. One‐way sensitivity analyses identified individual parameters for expected value of partial perfect information analyses. Population expected value of perfect information and expected value of partial perfect information provided an upper bound on the cost of future research. Substantial uncertainty was identified, with left atrial appendage occlusion devices being preferred in only 47% of simulations. The expected value of perfect information was $8542 per patient and $227.3 million at a population level. The expected value of partial perfect information for the set of probability parameters represented the most important source of uncertainty, at $6875. Identified in 1‐way sensitivity analyses, the expected value of partial perfect information for the odds ratio for stroke with left atrial appendage occlusion compared with warfarin was calculated at $7312 per patient or $194.5 million at a population level. Conclusion The relative efficacy of stroke reduction with left atrial appendage occlusion devices in relation to warfarin is an important source of uncertainty. Improving estimates of this parameter should be the priority

  11. [Giant congenital intrapericardial left atrial appendage aneurysm: about a case and review of the literature].

    PubMed

    Zhari, Bouchra; Bellamlih, Habib; Boumdine, Hassan; Amil, Touriya; Bamous, Mehdi; En-Nouali, Hassan

    2016-01-01

    Left atrial appendage aneurysm is a very rare heart anomaly. It may be congenital or acquired, secondary to inflammatory or degenerative processes. Most cases are asymptomatic. The prevalence of these lesions in pediatric age has been very rarely reported. As it can cause potentially fatal arrhythmias or thrombus, surgery is required immediately after diagnosis. This study reports the case of a 14-year-old boy with rapidly progressive dyspnea, palpitations, sensation of repetitive dizziness and fainting, in whom congenital left atrial appendage aneurysm was detected. Diagnosis was based on coronary CTA data. The patient was successfully treated with surgical resection of the aneurysm.

  12. Left circumflex coronary artery occlusion due to a left atrial appendage closure device

    PubMed Central

    Katona, András; Temesvári, András; Szatmári, András; Forster, Tamás; Fontos, Géza

    2015-01-01

    Nowadays, percutaneous left atrial appendage (LAA) closure is spreading, and a large number of patients with this procedure have concomitant coronary artery disease. With the presented case it could be concluded that coronary angiography is recommended before LAA closure. PMID:25848378

  13. Coherex WAVECREST I Left Atrial Appendage Occlusion Study

    ClinicalTrials.gov

    2015-01-13

    Non-valvular Paroxysmal, Persistent, or Permanent Atrial Fibrillation; LAA Anatomy Amenable to Treatment by Percutaneous Technique; Anticoagulation Indication for Potential Thrombus Formation in the Left Atrium

  14. Obstructive membrane at the base of the left atrial appendage, a multi-imaging approach.

    PubMed

    Chejtman, Demián; Failo, Matías; Richarte Rueda, Valeria; Logarzo, Emilio; Barja, Luis; Benticuaga, Alejandro; Ayerdi, Maria Laura; Turri, Domingo; Baratta, Sergio; Aguirre, Pablo; Hita, Alejandro

    2015-05-01

    The left atrial appendage (LAA) is a small muscular extension that grows from the anterolateral wall of the left atrium, in the proximity of the left pulmonary veins. The presence of a membrane in the LAA is a rare clinical entity whose origin is not known. Its clinical implication in the genesis of atrial arrhythmias and thromboembolic risk remains unknown. We report a case of an obstructive membrane located at the base of the LAA, found incidentally in a young patient who was initially undergoing a transesophageal echocardiogram prior to an invasive treatment for atrial fibrillation.

  15. Transcatheter closure of the left atrial appendage: initial experience with the WATCHMAN device

    PubMed Central

    Ding, Jiandong; Zhu, Jian; Lu, Jing; Ding, Xiuxia; Zhang, Xiaoli; Lu, Wenbin; Ao, Mingqiang; Ma, Genshan

    2015-01-01

    Background: Atrial fibrillation (AF) is the most commonly encountered clinical arrhythmia, accounting for approximately one third of hospitalizations for cardiac rhythm disturbance. In patients with non-valvular AF, approximately 90% of thrombi are thought to arise from the left atrial appendage (LAA). Anticoagulation with warfarin has been the mainstay of therapy to reduce stroke risk in these patients; however, it is not without its complications including bleeding and drug interactions. Percutaneous left atrial appendage closure can be an alternative to warfarin treatment in patients with AF at high risk for thromboembolic events and/or bleeding complications. Methods: Patients with atrial fibrillation and CHADSVASc score ≥ 2, not eligible for anticoagulation, were submitted to left atrial appendage closure using the WATCHMAN device. The procedure was performed under general anaesthesia, and was guided by fluoroscopy and transoesophageal echocardiography. Results: Percutaneous LAA closure with the WATCHMAN device was performed in all patients. At 45-day follow-up no recurrent major adverse events and especially no thromboembolic events occurred. Conclusions: Transcatheter closure of the LAA with the WATCHMAN device is generally safe and feasible. Long-term follow-up will further reveal the risk and benefits of this therapy. PMID:26629008

  16. Cost effectiveness of left atrial appendage closure with the Watchman device for atrial fibrillation patients with absolute contraindications to warfarin

    PubMed Central

    Reddy, Vivek Y.; Akehurst, Ronald L.; Armstrong, Shannon O.; Amorosi, Stacey L.; Brereton, Nic; Hertz, Deanna S.; Holmes, David R.

    2016-01-01

    Aims Atrial fibrillation (AF) patients with contraindications to oral anticoagulation have had few options for stroke prevention. Recently, a novel oral anticoagulant, apixaban, and percutaneous left atrial appendage closure (LAAC) have emerged as safe and effective therapies for stroke risk reduction in these patients. This analysis assessed the cost effectiveness of LAAC with the Watchman device relative to apixaban and aspirin therapy in patients with non-valvular AF and contraindications to warfarin therapy. Methods and results A cost-effectiveness model was constructed using data from three studies on stroke prevention in patients with contraindications: the ASAP study evaluating the Watchman device, the ACTIVE A trial of aspirin and clopidogrel, and the AVERROES trial evaluating apixaban. The cost-effectiveness analysis was conducted from a German healthcare payer perspective over a 20-year time horizon. Left atrial appendage closure yielded more quality-adjusted life years (QALYs) than aspirin and apixaban by 2 and 4 years, respectively. At 5 years, LAAC was cost effective compared with aspirin with an incremental cost-effectiveness ratio (ICER) of €16 971. Left atrial appendage closure was cost effective compared with apixaban at 7 years with an ICER of €9040. Left atrial appendage closure was cost saving and more effective than aspirin and apixaban at 8 years and remained so throughout the 20-year time horizon. Conclusions This analysis demonstrates that LAAC with the Watchman device is a cost-effective and cost-saving solution for stroke risk reduction in patients with non-valvular AF who are at risk for stroke but have contraindications to warfarin. PMID:26838691

  17. Association Between the Left Atrial and Left Atrial Appendages Systole Strain Rate in Patients with Atrial Fibrillation

    PubMed Central

    Tan, Changming; OuYang, Minzhi; Kong, Demiao; Zhou, Xinmin

    2016-01-01

    Background The aim of this research was to explore the association between the left atrial (LA) and left atrial appendages (LAA) systole strain rate (SSR) in patients with atrial fibrillation (AF), and to provide evidence to aid in the assessment of disease progression. Material/Methods A total of 180 patients with AF were selected for the study (130 patients with paroxysmal AF (Par AF) and 50 patients with persistence AF (PerAF). In addition, 60 healthy individuals were selected as a control group. The total and side wall SSRs were calculated. Results The total SSR in the control group was higher than in the ParAF and PerAF groups (2.87±0.45 vs. 2.15±0.56 vs. 1.92±0.62 and 6.24±1.61 vs. 4.45±1.42 vs. 3.66±1.55). The total SSR of LAA was correlated with that of LA in the AF patient groups and the control group; the correlation coefficients were 0.720, 0.563, and 0.421. However, the ratio of total SSR of LAA to that of LA was not significant statistically different among the three groups (2.24±0.41 vs. 2.35±0.58 vs. 2.03±0.56). The posterior wall had the lowest SSRs in the control group and ParAF group. Conclusions The SSRs of AF patients were lower than that of healthy individuals, and the degree was associated with disease progression. The SSR was different in different side walls, and gradually shorten with disease progression. PMID:27988786

  18. Etiologic significance of enlargement of the left atrial appendage in adults

    SciTech Connect

    Green, C.E.; Kelley, M.J.; Higgins, C.B.

    1982-01-01

    Fifty-one patients were divided into two groups: 20 patients with proven rheumatic mitral valve disease (RMVD) and 31 patients with left atrial enlargement (LAE) of a nonrheumatic etiology. The latter group included patients with ischemic papillary muscle dysfunction, mitral valve prolapse, and congestive cardiomyopathy. Radiographic studies showed that enlargement of the left atrial appendage (LAAE) was present in 18 of 20 rheumatics but in only one of 31 nonrheumatics. There was no direct relationship between enlargement of the LAA and radiographic or echocardiographic left atrial size, degree of pulmonary venous hypertension (PVH), or presence of atrial fibrillation. It is postulated that rheumatic influammation of the LAA allows it to dilate out of proportion to the body of the left atrium. In the adult patient with radiographic findings of PVH, LAAE is a valuable and specific radiographic sign of rheumatic mitral valve disease.

  19. Catheter Ablation in Combination With Left Atrial Appendage Closure for Atrial Fibrillation

    PubMed Central

    Swaans, Martin J.; Alipour, Arash; Rensing, Benno J.W.M.; Post, Martijn C.; Boersma, Lucas V.A.

    2013-01-01

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting millions of individuals worldwide 1-3. The rapid, irregular, and disordered electrical activity in the atria gives rise to palpitations, fatigue, dyspnea, chest pain and dizziness with or without syncope 4, 5. Patients with AF have a five-fold higher risk of stroke 6. Oral anticoagulation (OAC) with warfarin is commonly used for stroke prevention in patients with AF and has been shown to reduce the risk of stroke by 64% 7. Warfarin therapy has several major disadvantages, however, including bleeding, non-tolerance, interactions with other medications and foods, non-compliance and a narrow therapeutic range 8-11. These issues, together with poor appreciation of the risk-benefit ratio, unawareness of guidelines, or absence of an OAC monitoring outpatient clinic may explain why only 30-60% of patients with AF are prescribed this drug 8. The problems associated with warfarin, combined with the limited efficacy and/or serious side effects associated with other medications used for AF 12,13, highlight the need for effective non-pharmacological approaches to treatment. One such approach is catheter ablation (CA), a procedure in which a radiofrequency electrical current is applied to regions of the heart to create small ablation lesions that electrically isolate potential AF triggers 4. CA is a well-established treatment for AF symptoms 14, 15, that may also decrease the risk of stroke. Recent data showed a significant decrease in the relative risk of stroke and transient ischemic attack events among patients who underwent ablation compared with those undergoing antiarrhythmic drug therapy 16. Since the left atrial appendage (LAA) is the source of thrombi in more than 90% of patients with non-valvular atrial fibrillation 17, another approach to stroke prevention is to physically block clots from exiting the LAA. One method for occluding the LAA is via percutaneous placement of the WATCHMAN

  20. Percutaneous left atrial appendage closure devices: safety, efficacy, and clinical utility

    PubMed Central

    Swaans, Martin J; Wintgens, Lisette IS; Alipour, Arash; Rensing, Benno JWM; Boersma, Lucas VA

    2016-01-01

    Atrial fibrillation (AF) is the most common arrhythmia treated in the clinical practice. One of the major complications of AF is a thromboembolic cerebral ischemic event. Up to 20% of all strokes are caused by AF. Thromboembolic cerebral ischemic event in patients with AF occurs due to atrial thrombi, mainly from the left atrial appendage (LAA). Prevention of clot formation with antiplatelet agents and especially oral anticoagulants (vitamin K antagonists or newer oral anticoagulants) has been shown to be effective in reducing the stroke risk in patients with AF but has several drawbacks with (major) bleedings as the most important disadvantage. Therefore, physical elimination of the LAA, which excludes the site of clot formation by surgical or percutaneous techniques, might be a good alternative. In this review, we discuss the safety, efficacy, and clinical utility of the Watchman™ LAA closure device. PMID:27621674

  1. A Review of the Relevant Embryology, Pathohistology, and Anatomy of the Left Atrial Appendage for the Invasive Cardiac Electrophysiologist

    PubMed Central

    DeSimone, Christopher V.; Gaba, Prakriti; Tri, Jason; Syed, Faisal; Noheria, Amit; Asirvatham, Samuel J.

    2016-01-01

    The three-dimensional morphology of the left atrial appendage provides the substrate for thrombus generation, and is a harbinger for embolic material due to its direct connection to the left-sided circulation. Appreciating the development of the appendage from mesodermal layer to its adult form provides the basis to improve exclusion from the atrial circulation, and thereby can lead to a significant reduction in stroke risk. This process also provides insight into the role of the left atrial appendage as an endocrine organ, its involvement in fluid homeostasis, and its connection to the autonomic nervous system. Knowledge of the surrounding structural arrangement is critical to identify landmarks from both an endocardial and epicardial perspective to improve targeted device placement. Furthermore, correlation of the left atrial appendage body, neck, and ostium to the surrounding anatomy can also improve both procedural efficacy and safety. In addition, a working knowledge of the regional anatomy adds a prudent degree of awareness for procedural complications, and allows for early identification and timely intervention as these situations arise. A detailed understanding of the left atrial appendage embryology, histology, and gross anatomy is imperative to identify the correct device and approach for each individual patient. In addition, this increased awareness can identify areas that are in need of further innovation, and thus provide the ability to adapt and refine existing technologies to overcome pitfalls currently facing catheter-based approaches. PMID:27087889

  2. Novel stroke risk reduction in atrial fibrillation: left atrial appendage occlusion with a focus on the Watchman closure device

    PubMed Central

    Alipour, Arash; Wintgens, Lisette I S; Swaans, Martin J; Balt, Jippe C; Rensing, Benno J W M; Boersma, Lucas V A

    2017-01-01

    Atrial fibrillation (AF) remains an important clinical problem with severe complications such as stroke, which especially harms those with risk factors as calculated by the CHADS2 or CHA2DS2-VASc. Until now, no therapy has proven 100% effective against AF. Since the left atrial appendage (LAA) is the most prominent nonvalvular AF-related thromboembolic source and (novel) oral anticoagulant [(N)OAC] carries the hazard of bleeding, LAA occlusion may be an alternative, especially in patients who are ineligible for (N)OAC therapy. In this review, we discuss several LAA occlusion techniques with a focus on the Watchman device since this device is the most thoroughly studied device of all. PMID:28293114

  3. Localization of atrial natriuretic peptide mRNA and immunoreactivity in the rat heart and human atrial appendage

    SciTech Connect

    Hamid, Q.; Wharton, J.; Terenghi, G.; Hassall, C.J.S.; Aimi, J.; Taylor, K.M.; Nakazato, H.; Dixon, J.E.; Burnstock, G.; Polak, J.M.

    1987-10-01

    The localization of mRNA encoding preproatrial natriuretic peptide was investigated in tissue sections and cultures of rat heart and in sections of human right atrial appendage using the technique of in situ hybridization with /sup 32/P- and /sup 35/S-labeled RNA probes. Rat atrial natriuretic peptide (ANP) transcripts were demonstrated in numerous atrial myocytes and, to a lesser extent, in ventricular myocytes in both tissue sections and newborn rat heart cultures. These findings are consistent with those obtained by RNA blot analysis of rat heart total RNA, indicating that a single prepro-ANP transcript of approx. 900 nucleotides was present in the ventricles as well as the atria. Using a /sup 35/S-labeled RNA probe for human ANP mRNA, ANP transcripts were also localized to the majority of myocytes in the human right atrial appendage. Only background levels of autoradiographic labeling were obtained when RNA probes identical to the coding sequence of rat or human ANP mRNA were used. A close correlation was found between the distribution of ANP immunoreactivity and prepro-ANP mRNA in these preparations. These results provide unequivocal evidence for the expression of the ANP gene in the rat ventricles, as well as the atria, because myocytes in these tissues have been established as the sites of both ANP localization and precursor biosynthesis. The combined use of cardiac cultures and in situ hybridization may be of value in future studies investigating the regulation of ANP synthesis in cardiac myocytes.

  4. Thromboembolism Prevention via Transcatheter Left Atrial Appendage Closure with Transeosophageal Echocardiography Guidance

    PubMed Central

    Palios, John; Paraskevaidis, Ioannis

    2014-01-01

    Atrial fibrillation (AF) is an independent risk factor for stroke. Anticoagulation therapy has a risk of intracerebral hemorrhage. The use of percutaneous left atrial appendage (LAA) closure devices is an alternative to anticoagulation therapy. Echocardiography has a leading role in LAA closure procedure in patient selection, during the procedure and during followup. A comprehensive echocardiography study is necessary preprocedural in order to identify all the lobes of the LAA, evaluate the size of the LAA ostium, look for thrombus or spontaneous echo contrast, and evaluate atrial anatomy, including atrial septal defect and patent foramen ovale. Echocardiography is used to identify potential cardiac sources of embolism, such as atrial septal aneurysm, mitral valve disease, and aortic debris. During the LAA occlusion procedure transeosophageal echocardiography provides guidance for the transeptal puncture and monitoring during the release of the closure device. Procedure-related complications can be evaluated and acceptable device release criteria such as proper position and seating of the occluder in the LAA, compression, and stability can be assessed. Postprocedural echocardiography is used for followup to assess the closure of the LAA ostium. This overview paper describes the emerging role of LAA occlusion procedure with transeosophageal echocardiography guidance as an alternative to anticoagulation therapy in patients with AF. PMID:24672720

  5. Percutaneous closure of a very large left atrial appendage using the Amplatzer amulet.

    PubMed

    Freixa, Xavier; Kwai Chan, Jason Leung; Tzikas, Apostolos; Garceau, Patrick; Basmadjian, Arsène; Ibrahim, Réda

    2013-10-01

    Although percutaneous left atrial appendage (LAA) closure is becoming a common procedure worldwide, there are still some anatomic limitations. The size of the LAA is one of the current limitations as the most popular devices do not allow the closure of very large LAAs. The new Amplatzer Cardiac Plug 2, also called "Amulet," has been redesigned not only to improve delivery and safety but also to allow the closure of larger LAAs. The present report describes the successful closure of a very large LAA using the Amulet.

  6. Cardiac procedures to prevent stroke: patent foramen ovale closure/left atrial appendage occlusion.

    PubMed

    Freixa, Xavier; Arzamendi, Dabit; Tzikas, Apostolos; Noble, Stephane; Basmadjian, Arsene; Garceau, Patrick; Ibrahim, Réda

    2014-01-01

    Stroke is a major contributor to population morbidity and mortality. Cardiac thromboembolic sources are an important potential cause of stroke. Left atrial appendage (LAA) thromboembolism in association with atrial fibrillation is a major contributor to stroke occurrence, particularly in elderly individuals. Patent foramen ovale (PFO) acts as a potential conduit from the right-sided circulation to the brain, and has been suggested to be an important factor in cryptogenic stroke in the young patients. Advances in interventional cardiology have made it possible to deal with these potential stroke sources (LAA and PFO), but the available methods have intrinsic limitations that must be recognized. Furthermore, the potential value of LAA and PFO closure depends on our ability to identify when the target structure is importantly involved in stroke risk; this is particularly challenging for PFO. This article addresses the clinical use of PFO and LAA closure in stroke prevention. We discuss technical aspects of closure devices and methods, questions of patient selection, and clinical trials evidence. We conclude that for PFO closure, the clinical trials evidence is thus far negative in the broad cryptogenic stroke population, but closure might nevertheless be indicated for selected high-risk patients. LAA closure has an acceptable balance between safety and efficacy for atrial fibrillation patients with high stroke risk and important contraindications to oral anticoagulation. Much more work needs to be done to optimize the devices and techniques, and better define patient selection for these potentially valuable procedures.

  7. Morphological features of the left atrial appendage in consecutive coronary computed tomography angiography patients with and without atrial fibrillation

    PubMed Central

    Parkkonen, Johannes; Hedman, Marja; Muuronen, Antti; Onatsu, Juha; Mustonen, Pirjo; Vanninen, Ritva; Taina, Mikko

    2017-01-01

    The majority of intracardiac thrombi form in the left atrial appendage (LAA). Enlargement of this structure, together with certain morphological features, may indicate a predisposition to the formation of thrombi and subsequent cardioembolic stroke. Thus far, studies on LAA morphology have largely focused on those patients with atrial fibrillation (AF). Taking a different approach, we investigated the variation in LAA morphology in a consecutive patient population with and without AF. We evaluated 808 consecutive patients (529 females; mean age 52.5±9.9 years) who underwent coronary artery computed tomography angiography (CCTA), the majority of whom (749) had no history of AF. We assessed the length, lobe number, and morphological classification of their LAAs. Demographic data and medical histories were collated from medical records and then correlated with LAA morphology. The proportions of each of the four morphological classes of LAA for the overall vs. non-AF population were: WindSock, 62.3/61.5%; Cactus, 18.6/18.8%; ChickenWing, 10.0/10.0%; and CauliFlower, 9.2/9.6%. Age (p<0.001; r = 0.156) and female gender (p<0.001) were both found to be associated with an increased body surface area (BSA)-related LAA length. Male patients were more likely to manifest multi-lobed (p = 0.003) LAAs, and overweight patients with a greater number of multi-lobed LAA morphological classes (p = 0.010). No associations with morphological LAA features could be found for patients with diabetes, hypertension, or dyslipidemia. Nor did the size of the left atrium exhibit any correlation with BSA-related LAA length. In the overall and non-AF populations, aging and female gender were associated with longer BSA-indexed LAAs. PMID:28288200

  8. The Amplatzer™ Cardiac Plug 2 for left atrial appendage occlusion: novel features and first-in-man experience.

    PubMed

    Freixa, Xavier; Chan, Jason L K; Tzikas, Apostolos; Garceau, Patrick; Basmadjian, Arsène; Ibrahim, Réda

    2013-01-22

    Percutaneous left atrial appendage (LAA) closure is becoming a frequently performed procedure for patients with atrial fibrillation and high haemorrhagic risk. The Amplatzer™ Cardiac Plug (ACP) is one of the most commonly used devices for this purpose. Despite high success rate and low procedure risk associated with the ACP, a second generation of the device is now available. The new ACP has been designed to facilitate the implantation process, improve sealing performance and further reduce the risk of complications. The present report focuses on the novel features of the second generation of the Amplatzer™ Cardiac Plug (ACP 2 or Amulet™) and describes the first-in-man experience.

  9. Far field R-wave sensing in Myotonic Dystrophy type 1: right atrial appendage versus Bachmann's bundle region lead placement.

    PubMed

    Russo, Vincenzo; Nigro, Gerardo; Antonio Papa, Andrea; Rago, Anna; Di Meo, Federica; Cristiano, Anna; Molino, Antonio; Calabrò, Raffaele; Giovanna Russo, Maria; Politano, Luisa

    2014-10-01

    Aim of the present study was to investigate far field R-wave sensing (FFRS) timing and characteristics in 34 Myotonic Dystrophy type 1 (DM1) patients undergoing dual chamber pacemaker implantation, comparing Bachmann's bundle (BB) stimulation (16 patients) site with the conventional right atrial appendage (RAA) pacing site (18 patients). All measurements were done during sinus rhythm and in supine position, with unipolar (UP) and bipolar (BP) sensing configuration. The presence, amplitude threshold (FFRS trsh) and FFRS timing were determined. There were no differences between both atrial sites in the Pmin and Pmean values of sensed P-wave amplitudes, as well as between UP and BP sensing configurations. The FFRS trsh was lower at the BB region in comparison to the RAA site. The mean BP FFRS trsh was significantly lower than UP configuration in both atrial locations. There were no significant differences in atrial pacing threshold, sensing threshold and atrial lead impedances at the implant time and at FFRS measurements. Bachmann's bundle area is an optimal atrial lead position for signal sensing as well as conventional RAA, but it offers the advantage of reducing the oversensing of R-wave on the atrial lead, thus improving functioning of standard dual chamber pacemakers in DM1 patients.

  10. Interventional left atrial appendage occlusion: added value of 3D transesophageal echocardiography for device sizing.

    PubMed

    Goebel, Björn; Wieg, Stephanie; Hamadanchi, Ali; Otto, Sylvia; Jung, Christian; Kretzschmar, Daniel; Figulla, Hans R; Christian Schulze, P; Poerner, Tudor C

    2016-09-01

    Aim of this study was the assessment of left atrial appendage (LAA) dimensions comparing 2D- to 3D-TEE measurements in patients with nonvalvular atrial fibrillation undergoing percutaneous LAA occlusion. Patients underwent transesophageal echocardiography (TEE) before, during and 45 days after intervention. The maximal LAA orifice diameters in 2D-TEE (LODmax 2D) were obtained from multiple views. Test-retest reliability (screening vs. implantation), inter- and intra-observer variability for echocardiographic parameters were assessed by two independent examiners. Overall, 74 patients underwent percutaneous LAA occlusion. 2D-TEE significantly underestimated the maximal LAA orifice diameter compared with 3D-TEE (screening LODmax 2D 21.11 ± 2.75 mm vs. 22.52 ± 3.45 mm for LODmax 3D, p < 0.001; during implantation LODmax 2D 21.56 ± 3.48 mm vs. 22.99 ± 3.24 mm for LODmax 3D, p < 0.001). The intraobserver and interobserver variability calculated as coefficient of variation (CV) were both lower for the 3D-TEE quantification of the maximal orifice diameter (intraobserver CV for 3D-TEE 6.07 % vs. 9.31 % for 2D-TEE; interobserver CV for 3D-TEE 6.73 % vs. 9.69 % for 2D-TEE). Compared to 3D-TEE the test-retest reliability of 2D-TEE showed a lower intraclass correlation coefficient calculated as average of raters (0.92 for 3D-TEE vs. for 2D-TEE 0.78). Firstly, 2D-TEE significantly underestimates the maximal LAA orifice diameter compared to 3D-TEE. Secondly, 3D-TEE measurements are associated with a lower observer variability and higher reliability than 2D-TEE.

  11. Resolution of massive left atrial appendage thrombi with rivaroxaban before balloon mitral commissurotomy in severe mitral stenosis

    PubMed Central

    Li, Yuechun; Lin, Jiafeng; Peng, Chen

    2016-01-01

    Abstract Rationale: Data on nonvitamin K antagonist oral anticoagulant being used for the treatment of LAA thrombi are limited only in nonvalvular atrial fibrillation. There are no data on the antithrombotic efficacy and safety of nonvitamin K antagonist oral anticoagulant in the resolution of left atrial appendage (LAA) thrombi in patients with rheumatic mitral stenosis. Patient concerns: A 49-year-old woman with known rheumatic mitral stenosis and atrial fibrillation was referred for percutaneous transvenous mitral commissurotomy because of progressive dyspnea on exertion over a period of 3 months. Diagnoses: Transesophageal echocardiography (TEE) demonstrated a large LAA thrombus protruding into left atria cavity before the procedure. Interventions: Direct factor Xa (FXa) inhibitor rivaroxaban (20 mg/d) was started for the patient. After 3 weeks of rivaroxaban treatment TEE showed a relevantly decreased thrombus size, and a complete thrombus resolution was achieved after 5 weeks of anticoagulant therapy with the FXa inhibitor. Outcomes: To the best of our knowledge, this is the first documented case of large LAA thrombus resolution with nonvitamin K antagonist oral anticoagulant in severe mitral stenosis, and in which percutaneous transvenous mitral commissurotomy was performed subsequently. Lessons: The report indicated that rivaroxaban could be a therapeutic option for mitral stenosis patients with LAA thrombus. Further study is required before the routine use of rivaroxaban in patients with rheumatic mitral stenosis and atrial fibrillation. PMID:27930571

  12. Potential uselessness and futility of left atrial appendage occlusion and patent foramen ovale closure in cardioembolic stroke.

    PubMed

    Nicolosi, Gian L

    2017-02-16

    International guidelines indicate that interventional closure of left atrial appendage and patent foramen ovale may be considered in selected patients for stroke prevention. These procedures appear, however, from the published literature, at high risk of uselessness and futility in the single case, if not even capable to induce harm and adverse events. In fact, all reported systematic reviews and meta-analyses have not shown in a convincing manner the superiority of these procedures in stroke prevention, taking into account the occurrence of possible complications also, as compared with alternative medical treatment. On the basis of these considerations, it becomes very difficult to define always and unequivocally how adequate and complete was the information when given to each single candidate patient before the procedure by the Heart Team, the left atrial appendage occlusion Team or patent foramen ovale closure Team, potentially involved in conflict of interest. Before indicating these procedures, a complete diagnostic work-up should then be planned for each single patient to identify and treat not only one, but all concomitant risk factors and potential different cardioembolic sources. It could also be suggested to have, for each single candidate patient, a second independent opinion from physicians not involved in the procedure and possibly not operating in the same institution. This prudential approach could reduce in each single case the risk of uselessness, futility and even potential harm and adverse events of those procedures.

  13. Differences in atrial fibrillation-associated proteins between the left and right atrial appendages from patients with rheumatic mitral valve disease: A comparative proteomic analysis

    PubMed Central

    Liu, Hai; Chen, Guangxian; Zheng, Hongsheng; Qin, Han; Liang, Mengya; Feng, Kangni; Wu, Zhongkai

    2016-01-01

    The majority of proteomic studies have focused on identifying atrial fibrillation (AF)-associated proteins in the right atrium (RA), thus potential differences in AF-associated proteins between the RA and left atrium (LA) remain unknown. The aim of the present study was to perform proteomic analysis to compare the potential differences in AF-associated proteins between the right atrial appendage (RAA) and left atrial appendage (LAA) in patients with rheumatic mitral valve disease (RMVD). RAA and LAA tissues were obtained from 18 patients with RMVD (10 with AF) during mitral valve replacement surgery. Two-dimensional fluorescence difference gel electrophoresis (2-D DIGE) proteomics analysis was performed using these tissues to identify AF-associated proteins in RAA and LAA. Subsequently, the proteomics data was validated using western blot analysis of nine selected proteins. In RAA, 32 AF-associated proteins were significantly dysregulated (15 upregulated and 17 downregulated). In LAA, 31 AF-associated proteins were significantly dysregulated (13 upregulated and 18 downregulated). Among these AF-associated proteins, 17 were AF-associated in both RAA and LAA, 15 were AF-associated only in RAA, and 14 were AF-associated only in LAA. Amongst the differentially expressed proteins, western blot analysis validated the results for 6 AF-associated proteins, and demonstrated similar distributions in RAA and LAA compared with the 2-D DIGE results. Of these proteins, 2 proteins were AF-associated in both RAA and LAA, 2 were AF-associated only in RAA, and 2 were AF-associated only in LAA. Additionally, the different distributions of AF-associated proteins in the RAA and LAA of patients with RMVD was analyzed, which may reflect the different regulatory mechanisms of the RA and LA in AF. These findings may provide new insights into the underlying molecular mechanisms of AF in patients with RMVD. PMID:27667121

  14. Limb ischemia, an alarm signal to a thromboembolic cascade - renal infarction and nephrectomy followed by surgical suppression of the left atrial appendage.

    PubMed

    Caraşca, Cosmin; Borda, Angela; Incze, Alexandru; Caraşca, Emilian; Frigy, Attila; Suciu, HoraŢiu

    2016-01-01

    We present the case of a 55-year-old male with mild hypertension and brief episodes of paroxysmal self-limiting atrial fibrillation (AF) since 2010. Despite a small cardioembolic risk score, CHA2DS2-Vasc=1 (Congestive heart failure, Hypertension, Age=75, Diabetes melitus, prior Stroke), the patient is effectively anticoagulated using acenocumarol. In December 2014, he showed signs of plantar transitory ischemia, for which he did not address the doctor. In early January 2015, he urgently presented at the hospital with left renal pain, caused by a renal infarction, diagnosed by computed tomography (CT) angiography. Left nephrectomy was performed with pathological confirmation. He was discharged with effective anticoagulation treatment. Within the next two weeks, he suffered a transitory ischemic event and a stroke, associated with right sided hemiparesis. On admission, AF was found and converted to sinus rhythm with effective anticoagulation - international normalized ratio (INR) of 2.12. Transthoracic echocardiography detected no pathological findings. Transesophageal echocardiography showed an expended left atrial appendage (LAA) with a slow blood flow (0.2 m÷s) and spontaneous echocontrast. Considering these clinical circumstances, surgical LAA suppression was decided on as a last therapeutic resort. Postoperative evolution was favorable; the patient is still free of ischemic events, one year post-intervention. Some morphological and hemodynamic characteristics of LAA may add additional thromboembolic risk factors, not included in scores. Removing them by surgical LAA suppression may decrease the risk of cardioembolic events. Intraoperative presence of thrombus makes it an indisputable proof.

  15. Percutaneous balloon mitral valvuloplasty and closure of the left atrial appendage: Synergy of two procedures in one percutaneous intervention.

    PubMed

    Gemma, Daniele; Moreno Gómez, Raúl; Fernández de Bobadilla, Jaime; Galeote García, Guillermo; López Fernandez, Teresa; López-Mínguez, Jose R; López-Sendón, José L

    2016-11-01

    Mitral stenosis (MS) is frequently associated with the development of atrial fibrillation (AF) as a consequence of hemodynamic and inflammatory changes in the left atrium. Both conditions predispose to thrombus formation, with frequent involvement of the left atrial appendage (LAA), and consequent increase in the incidence of systemic thromboembolic events. Percutaneous mitral valvuloplasty (PMV) reduces the risk of thromboembolism in patients with significant mitral stenosis. Percutaneous LAA closure is also associated with a reduction in thromboembolic risk in patients with AF, but there are no data regarding the use of this technique in patients with significant mitral valve disease. We report the case of a 57-year-old-woman with significant MS and permanent AF, in New York Heart Association functional class II, who despite adequate oral anticoagulation with acenocoumarol, presented several clinical episodes of systemic thromboembolism in the last four years. It was decided to perform a combined percutaneous procedure, including both PMV and percutaneous LAA closure with the Amplatzer Cardiac Plug device. No significant acute complications occurred and the patient was discharged on indefinite treatment with acenocoumarol associated with aspirin 100 mg/d for three months. After a one-year follow-up, there have been no new embolic episodes or other complications.

  16. Analysis of real-time three dimensional transesophageal echocardiography in the assessment of left atrial appendage function in patients with atrial fibrillation

    PubMed Central

    Gan, Lin; Yu, Lan; Xie, Manying; Feng, Wei; Yin, Jiabao

    2016-01-01

    The aim of the study was to examine changes in left atrial appendage volume (LAA-V) in patients with non-valvular atrial fibrillation (AF) using real-time three-dimensional transesophageal echocardiography (RT3D-TEE) and evaluate the prediction value on the high risk of thrombosis of LAA. Using RT3D-TEE we measured: i) LAA peak empty velocity (LAA-PEV), ii) LAA-V including LAA end-diastolic volume (LAA-EDV) and end-systolic volume (LAA-ESV). We also calculated LAA ejection fraction (LAA-EF). RT3D-TEE was applied in 20 control cases and 74 patients with non-valvular AF. According to the presence of thrombosis, 74 patients were divided into the no thrombosis group (NTH group, n=52) and thrombosis group (TH group, n=22). Our results showed that there were significant differences in LAA-V and LAA-EF values in different groups (P<0.05). LAA-EDV moderately correlated with LAA-PEV (r=−0.531, P<0.001) while LAA-ESV demonstrated a strong correlation with LAA-PEV (r=−0.741, P<0.001). LAA-EF also showed a strong correlation with LAA-PEV (r=0.693, P<0.001). Through receiver operating characteristic (ROC) curves, the cut-off values of LAA-EDV and LAA-ESV in thrombosis of LAA were 18.45 and 9.69 ml, respectively. RT3D-TEE effectively evaluated the LAA-V, LAA-PEV and LAA-EF parameters, and proved to be valuable in the process of evaluation of thrombosis of LAA. PMID:27882157

  17. A meta-analysis for efficacy and safety evaluation of transcatheter left atrial appendage occlusion in patients with nonvalvular atrial fibrillation

    PubMed Central

    Wei, Zhonghai; Zhang, Xinlin; Wu, Han; Xie, Jun; Dai, Qing; Wang, Lian; Xu, Biao

    2016-01-01

    Abstract Objectives: This meta-analysis was conducted to evaluate the efficacy and safety of transcatheter left atrial appendage (LAA) occlusion in patients with nonvalvular atrial fibrillation. Methods: The randomized controlled trials (RCT) or observational studies with any transcatheter LAA occlusion devices were searched in PubMed, Embase, and Cochrane library from inception to November 2015. The incidence rates from individual studies were combined to evaluate the procedural efficacy and safety, including all-cause death, cardiac/neurological death, stroke, transient ischemic attack (TIA), thrombosis, hemorrhagic complications, and pericardial effusion/tamponade. Results: Thirty-eight studies involving 3585 patients and 6 different occlusion devices were eligible for our inclusion criteria. The procedural failure rate for LAA closure was 0.02 (95% CI: 0.02–0.03). The all-cause mortality was 0.03 (95% CI: 0.02–0.03) and cardiac/neurological mortality was 0 (95% CI: 0.00–0.01). The stroke/TIA rate was estimated only 0.01 (95% CI: 0.01–0.01). The incidence of thrombus on devices was 0.01 (95% CI: 0.01–0.02). The major hemorrhagic complication rate was estimated 0.01 (95% CI: 0.00–0.01). Pericardial effusion/tamponade was estimated 0.02 (95% CI: 0.02–0.03). No heterogeneity was observed for above pooled estimates (I2 = 0). In devices subgroups analysis, the all-cause mortality and cardiac/neurological mortality of PLAATO group were the highest (P = 0.01 and P < 0.01 respectively), whereas the incidence of thrombus on devices in the ACP group was the highest (P < 0.01). In follow-up period subgroups analysis, there were significant differences in all-cause death, stroke/TIA, major hemorrhage, and pericardial effusion/tamponade events between the shorter and longer follow-up period subgroups (P < 0.05). However, the differences among the subgroups were numerically small. Conclusions: the pooled data demonstrated that transcatheter

  18. Roles of real-time three-dimensional transesophageal echocardiography in peri-operation of transcatheter left atrial appendage closure

    PubMed Central

    Zhou, Qing; Song, Hongning; Zhang, Lan; Deng, Qing; Chen, Jinling; Hu, Bo; Wang, Yijia; Guo, Ruiqiang

    2017-01-01

    Abstract Left atrial appendage (LAA) closure is a new treatment option for the prevention of stroke in patients with nonvalvular atrial fibrillation (AF). Conventional 2-dimensional transesophageal echocardiography (2D TEE) has some limitations in the imaging assessment of LAA closure. Real-time 3-dimensional transesophageal echocardiography (RT-3D TEE) allows for detailed morphologic assessment of the LAA. In this study, we aim to determine the clinical values of RT-3D TEE in the periprocedure of LAA closure. Thirty-eight persistent or paroxysmal AF patients with indications for LAA closure were enrolled in this study. RT-3D TEE full volume data of the LAA were recorded before operation to evaluate the anatomic feature, the landing zone dimension, and the depth of the LAA. On this basis, selection of LAA closure device was carried out. During the procedure, RT-3D TEE was applied to guide the interatrial septal puncture, device operation, and evaluate the occlusion effects. The patients were follow-up 1 month and 3 months postclosure. Twenty-eight (73.7%) patients with AF received placement of LAA occlusion device under RT-3D TEE. Eleven cases with single-lobe LAAs were identified using RT-3D TEE, among which 4 showed limited depth. Seventeen cases showed bilobed or multilobed LAA. Seven cases received LAA closure using Lefort and 21 using LAmbre based on the 3D TEE and radiography. The landing zone dimension of the LAA measured by RT-3D TEE Flexi Slice mode was better correlated with the device size used for occlusion (r = 0.90) than 2D TEE (r = 0.88). The interatial septal puncture, the exchange of the sheath, as well as the release of the device were executed under the guidance of RT-3D TEE during the procedure. The average number of closure devices utilized for optimal plugging was (1.11 ± 0.31). There were no clinically unacceptable residual shunts, pericardial effusion, or tamponade right after occlusion. All the patients had the device well

  19. Efficacy and Safety of the WATCHMAN Left Atrial Appendage System for Stroke Prevention in Chinese Patients with Nonvalvular Atrial Fibrillation: A Single-center, Prospective, Observational Study

    PubMed Central

    Huang, Wei-Ping; Zhang, Yong-Hua; He, Lei; Su, Xi; Yang, Xin-Wei; Guo, Zai-Xiong

    2017-01-01

    Background: In patients with nonvalvular atrial fibrillation (NVAF), embolic stroke is thought to be associated with left atrial appendage (LAA) thrombi. The WATCHMAN LAA Occlusion Device has been shown to be noninferior to conventional oral anticoagulation with warfarin for stroke prevention in patients with NVAF. This study aimed to evaluate the procedural feasibility, safety and 12-month outcomes of the WATCHMAN LAA Occlusion Device in NVAF patients with high risk for stroke in China. Methods: The clinical data of 106 NVAF patients, who were consecutively underwent LAA closure with the WATCHMAN Device between April 2014 and May 2015, were collected. Patients were followed up at 1, 3, 6, and 12 months after discharge. A transesophageal echocardiograph was performed at 45 days after implantation and repeated in case of an unexpected event during the follow-up period. Results: This study included 106 NVAF patients with a mean age of 64.2 ± 8.6 years (ranging from 50 to 88 years), and the mean CHA2DS2-VASc score of all patients was 3.6 ± 1.6 (ranging from 2 to 9). Among those 106 NVAF patients, 100 (94.3%) patients were implanted with the device successfully. The procedural success rate was 94.3% (100/106), and the occlusion rate was 100.0% (100/100). There were one tamponade, one ischemic stroke, and eight minor pericardial effusions during hospitalization. During 12-month follow-up period, two patients developed a thrombus layer on the device that resolved with additional anticoagulation: one with visible device-thrombus experienced transient ischemic stroke, and one had a hemorrhagic stroke. There were no deaths in this study. The overall survival rate was 100.0%, and nonmajor adverse event rate was 95.0% (95/100). In this study, the expected annual rate of ischemic stroke risk in these patients according to the CHA2DS2-VASc score was 4.0%, while the observed ischemic stroke rate was 2.0% per year. Conclusions: LAA closure with the WATCHMAN Device was feasible

  20. Preservation of high-energy phosphates in human myocardium. A phosphorus 31-nuclear magnetic resonance study of the effect of temperature on atrial appendages

    SciTech Connect

    Deslauriers, R.; Keon, W.J.; Lareau, S.; Moir, D.; Saunders, J.K.; Smith, I.C.; Whitehead, K.; Mainwood, G.W.

    1989-09-01

    After prolonged exposure to low temperatures (1 and 4{degrees}C), human atrial trabeculae show poor recovery of contraction. At somewhat higher temperatures (12 and 20{degrees}C), recovery is much better. Although better preservation of adenosine triphosphate and therefore improved contractile recovery might be expected after exposure to lower temperatures, it remained possible that, below a certain temperature, adenosine triphosphate-generating mechanisms could be slowed more than adenosine triphosphate utilization. To investigate this phenomenon further, we followed the time course of metabolic changes in human atrial appendages, harvested during cardiac bypass operations, at 1, 4, 12, and 20{degrees}C using high-resolution 31P and 1H nuclear magnetic resonance spectroscopy. The results are quantitated by correlation with data obtained from biochemical assays on quick-frozen tissues. Initial adenosine triphosphate levels in myocytes of human atrial appendages are 3.3 to 4.3 mumol.gm-1 tissue wet weight. At 20{degrees}C, adenosine triphosphate disappears after 6 hours; at 12{degrees}C, about half the initial adenosine triphosphate is still observable at this time; at 4{degrees}C or 1{degree}C, the decline is still slower. Only a small contribution toward adenosine triphosphate maintenance comes from creatine phosphate, since creatine phosphate, inorganic phosphate, and total creatine levels in the appendage are low (less than 2 mumol.gm-1 tissue wet weight). Glycolysis is active at all temperatures; the rate of glycolysis correlates positively with increasing temperature. Adenosine triphosphate generated by glycolysis falls just short of demand at all temperatures, but the difference is small at 1 and 4{degrees}C.

  1. Effects of combined carotid chemoreceptor and atrial receptor stimulation on renal blood flow in anaesthetized dogs.

    PubMed Central

    Kappagoda, C T; Karim, F; Mackay, D

    1983-01-01

    In dogs anaesthetized with chloralose and artificially ventilated, carotid chemoreceptors were stimulated by changing the perfusate of the vascularly isolated carotid bifurcations from arterial to venous blood. Left atrial receptors were stimulated by distending balloons in two pulmonary vein-left atrial junctions and in this left atrial appendage. The left renal blood flow was measured by an electromagnetic flow meter at a constant systemic (renal) arterial pressure in preparations in which heart rate changes were prevented by administration of propranolol hydrochloride (0.5 mg kg-1) and atropine sulphate (0.4 mg kg-1). Muscular movement was prevented by gallamine triethiodide (0.2 mg kg-1). Stimulation of left atrial receptors resulted in a significant increase (P less than 0.001) in renal blood flow of 5.6 +/- 0.88 ml min-1 100 g-1 renal mass from a control of 223 ml min-1 100 g-1 renal mass. The responses were abolished by cooling the cervical vagus nerves to 6-8 degrees C. Stimulation of carotid chemoreceptors, by perfusion of the carotid bifurcations by venous blood, caused a decrease in renal blood flow of 20 +/- 6.9 ml min-1 100 g-1 renal mass from 224 ml min-1 100 g-1 renal mass. Stimulation of left atrial receptors during venous perfusion of carotid chemoreceptors resulted in an increase in renal blood flow of 10.9 +/- 1.82 ml min-1 100 g-1 renal mass from 208 ml min-1 100 g-1 renal mass. These results show that atrial receptors and chemoreceptors can interact in their effects on renal blood flow. PMID:6410054

  2. The New 3D Printed Left Atrial Appendage Closure with a Novel Holdfast Device: A Pre-Clinical Feasibility Animal Study

    PubMed Central

    Brzeziński, M.; Bury, K.; Dąbrowski, L.; Holak, P.; Sejda, A.; Pawlak, M.; Jagielak, D.; Adamiak, Z.; Rogowski, J.

    2016-01-01

    Introduction Many patients undergoing cardiac surgery have risk factors for both atrial fibrillation (AF) and stroke. The left atrial appendage (LAA) is the primary site for thrombi formation. The most severe complication of emboli derived from LAA is stroke, which is associated with a 12-month mortality rate of 38% and a 12-month recurrence rate of 17%. The most common form of treatment for atrial fibrillation and stroke prevention is the pharmacological therapy with anticoagulants. Nonetheless this form of therapy is associated with high risk of major bleeding. Therefore LAA occlusion devices should be tested for their ability to reduce future cerebral ischemic events in patients with high-risk of haemorrhage. Aim The aim of this study was to evaluate the safety and feasibility of a novel left atrial appendage exclusion device with a minimally invasive introducer in a swine model. Materials and Methods A completely novel LAA device, which is composed of two tubes connected together using a specially created bail, was designed using finite element modelling (FEM) to obtain an optimal support force of 36 N at the closure line. The monolithic form of the occluder was obtained by using additive manufacturing of granular PA2200 powder with the technology of selective laser sintering (SLS). Fifteen swine were included in the feasibility tests, with 10 animals undergoing fourteen days of follow-up and 5 animals undergoing long-term observation of 3 months. For one animal, the follow-up was further prolonged to 6 months. The device was placed via minithoracotomy. After the observation period, all of the animals were euthanized, and their hearts were tested for LAA closure and local inflammatory and tissue response. Results After the defined observation period, all fifteen hearts were explanted. In all cases the full closure of the LAA was achieved. The macroscopic and microscopic evaluation of the explanted hearts showed that all devices were securely integrated in the

  3. A 64-slice multi-detector CT scan could evaluate the change of the left atrial appendage thrombi of the atrial fibrillation patient, which was reduced by warfarin therapy.

    PubMed

    Takeuchi, Hidekazu

    2011-08-19

    Curable cause of stroke is the left atrial appendage (LAA) thrombi of atrial fibrillation (AF) patients. Some AF patients have the LAA thrombi. It is very important to cure AF patients by warfarin. Transoesophageal echocardiography (TOE) is the usual clinical tool to detect the LAA thrombi. Recently, a 64-slice multi-detector CT (64-MDCT) scan enables us to display the LAA thrombi more easily than TOE. I reported a case that a 64-MDCT scan had been used successfully in displaying the change of the LAA thrombi reduced by warfarin therapy. The size of the LAA thrombi was reduced from 25.2 mm × 19.3 mm (figure 1) to 22.1 mm × 14.8 mm (figure 2) after the 3-month warfarin therapy. It was useful to estimate the LAA thrombi by a 64-MDCT scan to estimate LAA thrombi itself and the change of LAA thrombi to evaluate the effectiveness of warfarin therapy.

  4. Clinical impact of quantitative left atrial vortex flow analysis in patients with atrial fibrillation: a comparison with invasive left atrial voltage mapping.

    PubMed

    Lee, Jung Myung; Hong, Geu-Ru; Pak, Hui-Nam; Shim, Chi Young; Houle, Helene; Vannan, Mani A; Kim, Minji; Chung, Namsik

    2015-08-01

    Recently, left atrial (LA) vortex flow analysis using contrast transesophageal echocardiography (TEE) has been shown to be feasible and has demonstrated significant differences in vortex flow morphology and pulsatility between normal subjects and patients with atrial fibrillation (AF). However, the relationship between LA vortex flow and electrophysiological properties and the clinical significance of LA vortex flow are unknown. The aims of this study were (1) to compare LA vortex flow parameters with LA voltage and (2) to assess the predictive value of LA vortex flow parameters for the recurrence of AF after radiofrequency catheter ablation (RFCA). Thirty-nine patients with symptomatic non-valvular AF underwent contrast TEE before undergoing RFCA for AF. Quantitative LA vortex flow parameters were analyzed by Omega flow (Siemens Medical Solution, Mountain View, CA, USA). The morphology and pulsatility of LA vortex flow were compared with electrophysiologic parameters that were measured invasively. Hemodynamic, electrophysiological, and vortex flow parameters were compared between patients with and without early recurrence of AF after RFCA. Morphologic parameters, including LA vortex depth, length, width, and sphericity index were not associated with LA voltage or hemodynamic parameters. The relative strength (RS), which represents the pulsatility power of LA, was positively correlated with LA voltage (R = 0.53, p = 0.01) and LA appendage flow velocity (R = 0.73, p < 0.001) and negatively correlated with LA volume index (R = -0.56, p < 0.001). Patients with recurrent AF after RFCA showed significantly lower RS (1.7 ± 0.2 vs 1.9 ± 0.4, p = 0.048) and LA voltage (0.9 ± 0.7 vs 1.7 ± 0.8, p = 0.004) than patients without AF recurrence. In the relatively small LA dimension group (LA volume index ≤ 33 ml/m(2)), RS was significantly lower (2.1 ± 0.3 vs 1.7 ± 0.1, p = 0.029) in patients with the recurrent AF. Quantitative LA vortex flow analysis, especially RS

  5. The impact of surgical left atrial appendage amputation/ligation on stroke prevention in patients undergoing off-pump coronary artery bypass grafting.

    PubMed

    Endo, Daisuke; Kato, Tomoko S; Iwamura, Tai; Oishi, Atsumi; Yokoyama, Yasutaka; Kuwaki, Kenji; Inaba, Hirotaka; Amano, Atsushi

    2016-11-09

    Stroke is a major adverse event in patients developing atrial fibrillation (AF) after cardiac surgery. Surgical left atrial appendage amputation/ligation (LAA-A/L) during off-pump coronary artery bypass grafting (OPCAB) is routinely performed in our institution. We analyzed 578 consecutive patients (mean age 69 years, male 82%) undergoing OPCAB with or without concomitant LAA-A/L from 2011 to 2014 at our institution in a prospective observational manner. The safety and efficacy of the concomitant LAA-A/L on preventing early (<30 days) and overall postoperative stroke were examined. A total of 193 patients (33.4%) underwent LAA-A/L, consisting of amputation in 154 and ligation in 39 patients (80 and 20% of the cases, respectively). Preoperative characteristics, operative time, requirement of blood transfusion, and 30-day mortality were not significantly different between those with and without LAA-A/L. The incidences of postoperative AF and early and overall stroke were not significantly different between the groups in the analysis based on a total cohort. In a subanalysis of patients without LAA-A/L, early and overall stroke occurred more frequently in those developing postoperative AF than those without AF (2.8 vs. 0%; p = 0.005, 6.2 vs. 1.5%; p = 0.017, respectively), while in patients receiving LAA-A/L, stroke incidences did not differ between those with and without AF. Multivariate logistic regression showed postoperative AF without LAA-A/L as the only independent positive predictor of overall stroke (OR 3.69, p = 0.03). Concomitant LAA-A/L with OPCAB can safely prevent postoperative stroke occurrence in case patients develop AF, the most common arrhythmia associated with stroke.

  6. Digitalis does not improve left atrial mechanical dysfunction after successful electrical cardioversion of chronic atrial fibrillation.

    PubMed

    Yujing, Wang; Congxin, Huang; Shaning, Yang; Lijun, Jin; Xiaojun, Hu; Gang, Wu; Qiang, Xie

    2010-05-01

    This study was designed to investigate whether administration of digitalis could improve mechanical function of left atrial appendage (LAA) and left atrium prospectively in patients with atrial stunning. Fifty-four consecutive patients in whom atrial stunning was observed immediately after cardioversion of chronic atrial fibrillation (AF) were randomized into digitalis or control group for 1 week following cardioversion. Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) were performed prior to, immediately following, 1 day after and 1 week after cardioversion to measure transmitral flow velocity and LAA flow velocity. Electrical cardioversion of AF elicited significantly slower left atrial appendage peak emptying velocity (LAA-PEV) and peak filling velocity (LAA-PFV) immediately following cardioversion in both groups. 1 day post cardioversion, there were no significant differences in transmitral E wave, A wave, E/A ratio, LAA-PEV, LAA-PFV or left atrial appendage ejection fraction (LAA-EF) between digitalis and control groups. 1 week post cardioversion, no significant differences were found in transmitral E wave, A wave, E/A ratio, LAA-PEV, LAA-PFV or LAA-EF between the two groups. The occurrence rates of spontaneous echo contrast were not significantly different between digitalis and control groups one day and one week post cardioversion. In conclusion, digitalis did not improve left atrial and appendage mechanical dysfunction following cardioversion of chronic AF. Digitalis did not prevent the development of spontaneous echo contrast in left atrial chamber and appendage. This may be due to the fact that digitalis aggravates intracellular calcium overload induced by chronic AF and has a negative effect on ventricular rate.

  7. An Experimental Investigation of Appendage-Flat Plate Junction Flow. Volume 1. Description.

    DTIC Science & Technology

    1986-12-01

    CENTER BET. S C DICKINSON UNLSIIDDEC 86 DTNSRDC-6/@5i-VOL-1 F/G 28/4 M EONMENOMINEEl MMMMhmmMhMl-EM mEEhEhhhEhhEI3 ENMhhMhhhhMMlM IMi ucaocop RESOUTION ...constructed out of a cear acryi sheet. Two problems were encountered. First, the acrylic sheet absorbs oil, thus reducing the surface tension forces on...pressure rises again as the appendage thins. This region is the pressure recovery region of the foil. There is a high pressure region near the trailing

  8. Epiploic appendagitis.

    PubMed

    Gandhi, Jamish; Gandhi, Natasha

    2009-01-01

    A 25-year-old female presented to the emergency department (ED) with a 1-day history of crampy left iliac fossa (LIF) abdominal pain. It was associated with both nausea and vomiting. On examination she was tender in the LIF with some guarding. Her observations were satisfactory and she was apyrexial. Urine dipstick and pregnancy stick were negative. The case was a diagnostic quandary. On ultrasound scan (USS) no acute gynaecological problems were found. Computed tomography (CT) of the abdomen showed epiploic appendagitis. This was managed conservatively with analgesia and antibiotics and the patient was discharged home pain free. She was followed up in the general surgical clinic 1 week later where she continued to be symptom free. She was discharged from general surgical care.

  9. Glycoproteomics Reveals Decorin Peptides with Anti-Myostatin Activity in Human Atrial Fibrillation

    PubMed Central

    Barallobre-Barreiro, Javier; Gupta, Shashi K.; Zoccarato, Anna; Kitazume-Taneike, Rika; Fava, Marika; Yin, Xiaoke; Werner, Tessa; Hirt, Marc N; Zampetaki, Anna; Viviano, Alessandro; Chong, Mei; Bern, Marshall; Kourliouros, Antonios; Domenech, Nieves; Willeit, Peter; Shah, Ajay M; Jahangiri, Marjan; Schaefer, Liliana; Fischer, Jens W.; Iozzo, Renato V.; Viner, Rosa; Thum, Thomas; Heineke, Joerg; Kichler, Antoine; Otsu, Kinya; Mayr, Manuel

    2016-01-01

    Background Myocardial fibrosis is a feature of many cardiac diseases. We used proteomics to profile glycoproteins in the human cardiac extracellular matrix (ECM). Methods Atrial specimens were analyzed by mass spectrometry after extraction of ECM proteins and enrichment for glycoproteins or glycopeptides. Results ECM-related glycoproteins were identified in left and right atrial appendages from the same patients. Several known glycosylation sites were confirmed. In addition, putative and novel glycosylation sites were detected. Upon enrichment for glycoproteins, peptides of the small leucine-rich proteoglycan decorin were consistently identified in the flow through. Out of all ECM proteins identified, decorin was found to be most fragmented. Within its protein core, eighteen different cleavage sites were identified. In contrast, no cleavage was observed for biglycan, the most closely related proteoglycan. Decorin processing differed between human ventricles and atria and was altered in disease. The C-terminus of decorin, important for the interaction with connective tissue growth factor, was predominantly detected in ventricles compared to atria. In contrast, atrial appendages from patients in persistent atrial fibrillation had higher levels of full-length decorin but also harbored a cleavage site that was not found in atrial appendages from patients in sinus rhythm. This cleavage site preceded the N-terminal domain of decorin that controls muscle growth by altering the binding capacity for myostatin. Myostatin expression was decreased in atrial appendages of patients with persistent atrial fibrillation and hearts of decorin null mice. A synthetic peptide corresponding to this decorin region dose-dependently inhibited the response to myostatin in cardiomyocytes and in perfused mouse hearts. Conclusions This proteomics study is the first to analyse the human cardiac ECM. Novel processed forms of decorin protein core, uncovered in human atrial appendages can regulate

  10. Hemodynamics of a functional centrifugal-flow total artificial heart with functional atrial contraction in goats.

    PubMed

    Shiga, Takuya; Shiraishi, Yasuyuki; Sano, Kyosuke; Taira, Yasunori; Tsuboko, Yusuke; Yamada, Akihiro; Miura, Hidekazu; Katahira, Shintaro; Akiyama, Masatoshi; Saiki, Yoshikatsu; Yambe, Tomoyuki

    2016-03-01

    Implantation of a total artificial heart (TAH) is one of the therapeutic options for the treatment of patients with end-stage biventricular heart failure. There is no report on the hemodynamics of the functional centrifugal-flow TAH with functional atrial contraction (fCFTAH). We evaluated the effects of pulsatile flow by atrial contraction in acute animal models. The goats received fCFTAH that we created from two centrifugal-flow ventricular assist devices. Some hemodynamic parameters maintained acceptable levels: heart rate 115.5 ± 26.3 bpm, aortic pressure 83.5 ± 10.1 mmHg, left atrial pressure 18.0 ± 5.9 mmHg, pulmonary pressure 28.5 ± 9.7 mmHg, right atrial pressure 13.6 ± 5.2 mmHg, pump flow 4.0 ± 1.1 L/min (left) 3.9 ± 1.1 L/min (right), and cardiac index 2.13 ± 0.14 L/min/m(2). fCFTAH with atrial contraction was able to maintain the TAH circulation by forming a pulsatile flow in acute animal experiments. Taking the left and right flow rate balance using the low internal pressure loss of the VAD pumps may be easier than by other pumps having considerable internal pressure loss. We showed that the remnant atrial contraction effected the flow rate change of the centrifugal pump, and the atrial contraction waves reflected the heart rate. These results indicate that remnant atria had the possibility to preserve autonomic function in fCFTAH. We may control fCFTAH by reflecting the autonomic function, which is estimated with the flow rate change of the centrifugal pump.

  11. The contribution of classical (beta1/2-) and atypical beta-adrenoceptors to the stimulation of human white adipocyte lipolysis and right atrial appendage contraction by novel beta3-adrenoceptor agonists of differing selectivities.

    PubMed

    Sennitt, M V; Kaumann, A J; Molenaar, P; Beeley, L J; Young, P W; Kelly, J; Chapman, H; Henson, S M; Berge, J M; Dean, D K; Kotecha, N R; Morgan, H K; Rami, H K; Ward, R W; Thompson, M; Wilson, S; Smith, S A; Cawthorne, M A; Stock, M J; Arch, J R

    1998-06-01

    The role of beta3- and other putative atypical beta-adrenoceptors in human white adipocytes and right atrial appendage has been investigated using CGP 12177 and novel phenylethanolamine and aryloxypropanolamine beta3-adrenoceptor (beta3AR) agonists with varying intrinsic activities and selectivities for human cloned betaAR subtypes. The ability to demonstrate beta1/2AR antagonist-insensitive (beta3 or other atypical betaAR-mediated) responses to CGP 12177 was critically dependent on the albumin batch used to prepare and incubate the adipocytes. Four aryloxypropanolamine selective beta3AR agonists (SB-226552, SB-229432, SB-236923, SB-246982) consistently elicited beta1/2AR antagonist-insensitive lipolysis. However, a phenylethanolamine (SB-220646) that was a selective full beta3AR agonist elicited full lipolytic and inotropic responses that were sensitive to beta1/2AR antagonism, despite it having very low efficacies at cloned beta1- and beta2ARs. A component of the response to another phenylethanolamine selective beta3AR agonist (SB-215691) was insensitive to beta1/2AR antagonism in some experiments. Because no [corrected] novel aryloxypropanolamine had a beta1/2AR antagonist-insensitive inotropic effect, these results establish more firmly that beta3ARs mediate lipolysis in human white adipocytes, and suggest that putative 'beta4ARs' mediate inotropic responses to CGP 12177. The results also illustrate the difficulty of predicting from studies on cloned betaARs which betaARs will mediate responses to agonists in tissues that have a high number of beta1- and beta2ARs or a low number of beta3ARs.

  12. Left atrial vascularised thrombus diagnosed by transoesophageal cross sectional echocardiography.

    PubMed Central

    Taams, M A; Gussenhoven, E J; Lancée, C T

    1987-01-01

    This report describes a patient with a Björk-Shiley mitral valve prosthesis in whom transoesophageal cross sectional echocardiography revealed a large vascularised mass within the left atrial appendage with smoke-like opacification of blood flow in the left atrium. Transoesophageal cross sectional echocardiography gave a detailed image of the lesion which was unobtainable with precordial cross sectional echocardiography. Images Fig 1 Fig 2 PMID:3426904

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

    PubMed

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

    2016-04-01

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

  14. Passive appendages generate drift through symmetry breaking

    PubMed Central

    Lācis, U.; Brosse, N.; Ingremeau, F.; Mazzino, A.; Lundell, F.; Kellay, H.; Bagheri, S.

    2014-01-01

    Plants and animals use plumes, barbs, tails, feathers, hairs and fins to aid locomotion. Many of these appendages are not actively controlled, instead they have to interact passively with the surrounding fluid to generate motion. Here, we use theory, experiments and numerical simulations to show that an object with a protrusion in a separated flow drifts sideways by exploiting a symmetry-breaking instability similar to the instability of an inverted pendulum. Our model explains why the straight position of an appendage in a fluid flow is unstable and how it stabilizes either to the left or right of the incoming flow direction. It is plausible that organisms with appendages in a separated flow use this newly discovered mechanism for locomotion; examples include the drift of plumed seeds without wind and the passive reorientation of motile animals. PMID:25354545

  15. 4D flow MRI assessment of right atrial flow patterns in the normal heart – influence of caval vein arrangement and implications for the patent foramen ovale

    PubMed Central

    Parikh, Jehill D.; Kakarla, Jayant; Keavney, Bernard; O’Sullivan, John J.; Ford, Gary A.; Blamire, Andrew M.; Hollingsworth, Kieren G.

    2017-01-01

    Aim To investigate atrial flow patterns in the normal adult heart, to explore whether caval vein arrangement and patency of the foramen ovale (PFO) may be associated with flow pattern. Materials and Methods Time-resolved, three-dimensional velocity encoded magnetic resonance imaging (4D flow) was employed to assess atrial flow patterns in thirteen healthy subjects (6 male, 40 years, range 25–50) and thirteen subjects (6 male, 40 years, range 21–50) with cryptogenic stroke and patent foramen ovale (CS-PFO). Right atrial flow was defined as vortical, helico-vortical, helical and multiple vortices. Time-averaged and peak systolic and diastolic flows in the caval and pulmonary veins and their anatomical arrangement were compared. Results A spectrum of right atrial flow was observed across the four defined categories. The right atrial flow patterns were strongly associated with the relative position of the caval veins. Right atrial flow patterns other than vortical were more common (p = 0.015) and the separation between the superior and inferior vena cava greater (10±5mm versus 3±3mm, p = 0.002) in the CS-PFO group. In the left atrium all subjects except one had counter-clockwise vortical flow. Vortex size varied and was associated with left lower pulmonary vein flow (systolic r = 0.61, p = 0.001, diastolic r = 0.63 p = 0.002). A diastolic vortex was less common and time-averaged left atrial velocity was greater in the CS-PFO group (17±2cm/sec versus 15±1, p = 0.048). One CS-PFO subject demonstrated vortical retrograde flow in the descending aortic arch; all other subjects had laminar descending aortic flow. Conclusion Right atrial flow patterns in the normal heart are heterogeneous and are associated with the relative position of the caval veins. Patterns, other than ‘typical’ vortical flow, are more prevalent in the right atrium of those with cryptogenic stroke in the context of PFO. Left atrial flow patterns are more homogenous in normal hearts and show a

  16. Atrial systole enhances intraventricular filling flow propagation during increasing heart rate

    PubMed Central

    Santhanakrishnan, Arvind; Okafor, Ikechukwu; Kumar, Gautam; Yoganathan, Ajit P.

    2016-01-01

    Diastolic fluid dynamics in the left ventricle (LV) has been examined in multiple clinical studies for understanding cardiac function in healthy humans and developing diagnostic measures in disease conditions. The question of how intraventricular filling vortex flow pattern is affected by increasing heart rate (HR) is still unanswered. Previous studies on healthy subjects have shown a correlation between increasing HR and diminished E/A ratio of transmitral peak velocities during early filling (E-wave) to atrial systole (A-wave). We hypothesize that with increasing HR under constant E/A ratio, E-wave contribution to intraventricular vortex propagation is diminished. A physiologic in vitro flow phantom consisting of a LV physical model was used for this study. HR was varied across 70, 100 and 120 beats per minute (bpm) with E/A of 1.1–1.2. Intraventricular flow patterns were characterized using 2D particle image velocimetry measured across three parallel longitudinal (apical-basal) planes in the LV. A pair of counter-rotating vortices was observed during E-wave across all HRs. With increasing HR, diminished vortex propagation occurred during E-wave and atrial systole was found to amplify secondary vorticity production. The diastolic time point where peak vortex circulation occurred was delayed with increasing HR, with peak circulation for 120 bpm occurring as late as 90% into diastole near the end of A-wave. The role of atrial systole is elevated for higher HR due to the limited time available for filling. Our baseline findings and analysis approach can be applied to studies of clinical conditions where impaired exercise tolerance is observed. PMID:26895781

  17. Passive control of a sphere by complex-shaped appendages

    NASA Astrophysics Data System (ADS)

    Bagheri, Shervin; Lacis, Ugis; Olivieri, Stefano; Mazzino, Andrea

    2015-11-01

    Appendages of various shapes and sizes (e.g. plumes, barbs, tails, feathers, hairs, fins) play an important role in dispersion and locomotion. In our previous work (Lacis, U. et al. Passive appendages generate drift through symmetry breaking. Nat. Commun. 5:5310, doi: 10.1038/ncomms6310, 2014), we showed that a free-falling cylinder with a splitter plate turns and drifts due to a symmetry-breaking instability (called inverted-pendulum instability or IPL). In other words, in a separated flow, the straight position of a short splitter plate is unstable and as a consequence a side force and a torque are induced on the cylinder. In this work, we seek the three-dimensional (3D) appendage shape (on a sphere at Re =200) that induces the largest drift of the sphere. We find that highly non-trivial shapes of appendages on a sphere increase the side force significantly compared to trivial shapes (such as an elliptic sheet). We also find that appendages may be designed to generate drift in either direction, that is, a free-falling sphere can drift either in the direction in which appendage is tilted or in the opposite direction depending on the particular geometry of the appendage. We discuss the physical mechanisms behind these optimal appendage shapes in the context of the IPL instability.

  18. Noninvasive assessment of left atrial maximum dP/dt by a combination of transmitral and pulmonary venous flow

    NASA Technical Reports Server (NTRS)

    Nakatani, S.; Garcia, M. J.; Firstenberg, M. S.; Rodriguez, L.; Grimm, R. A.; Greenberg, N. L.; McCarthy, P. M.; Vandervoort, P. M.; Thomas, J. D.

    1999-01-01

    OBJECTIVES: The study assessed whether hemodynamic parameters of left atrial (LA) systolic function could be estimated noninvasively using Doppler echocardiography. BACKGROUND: Left atrial systolic function is an important aspect of cardiac function. Doppler echocardiography can measure changes in LA volume, but has not been shown to relate to hemodynamic parameters such as the maximal value of the first derivative of the pressure (LA dP/dt(max)). METHODS: Eighteen patients in sinus rhythm were studied immediately before and after open heart surgery using simultaneous LA pressure measurements and intraoperative transesophageal echocardiography. Left atrial pressure was measured with a micromanometer catheter, and LA dP/dt(max) during atrial contraction was obtained. Transmitral and pulmonary venous flow were recorded by pulsed Doppler echocardiography. Peak velocity, and mean acceleration and deceleration, and the time-velocity integral of each flow during atrial contraction was measured. The initial eight patients served as the study group to derive a multilinear regression equation to estimate LA dP/dt(max) from Doppler parameters, and the latter 10 patients served as the test group to validate the equation. A previously validated numeric model was used to confirm these results. RESULTS: In the study group, LA dP/dt(max) showed a linear relation with LA pressure before atrial contraction (r = 0.80, p < 0.005), confirming the presence of the Frank-Starling mechanism in the LA. Among transmitral flow parameters, mean acceleration showed the strongest correlation with LA dP/dt(max) (r = 0.78, p < 0.001). Among pulmonary venous flow parameters, no single parameter was sufficient to estimate LA dP/dt(max) with an r2 > 0.30. By stepwise and multiple linear regression analysis, LA dP/dt(max) was best described as follows: LA dP/dt(max) = 0.1 M-AC +/- 1.8 P-V - 4.1; r = 0.88, p < 0.0001, where M-AC is the mean acceleration of transmitral flow and P-V is the peak velocity

  19. Quantification of left and right atrial kinetic energy using four-dimensional intracardiac magnetic resonance imaging flow measurements.

    PubMed

    Arvidsson, Per M; Töger, Johannes; Heiberg, Einar; Carlsson, Marcus; Arheden, Håkan

    2013-05-15

    Kinetic energy (KE) of atrial blood has been postulated as a possible contributor to ventricular filling. Therefore, we aimed to quantify the left (LA) and right (RA) atrial blood KE using cardiac magnetic resonance (CMR). Fifteen healthy volunteers underwent CMR at 3 T, including a four-dimensional phase-contrast flow sequence. Mean LA KE was lower than RA KE (1.1 ± 0.1 vs. 1.7 ± 0.1 mJ, P < 0.01). Three KE peaks were seen in both atria: one in ventricular systole, one during early ventricular diastole, and one during atrial contraction. The systolic LA peak was significantly smaller than the RA peak (P < 0.001), and the early diastolic LA peak was larger than the RA peak (P < 0.05). Rotational flow contained 46 ± 7% of total KE and conserved energy better than nonrotational flow did. The KE increase in early diastole was higher in the LA (P < 0.001). Systolic KE correlated with the combination of atrial volume and systolic velocity of the atrioventricular plane displacement (r(2) = 0.57 for LA and r(2) = 0.64 for RA). Early diastolic KE of the LA correlated with left ventricle (LV) mass (r(2) = 0.28), however, no such correlation was found in the right heart. This suggests that LA KE increases during early ventricular diastole due to LV elastic recoil, indicating that LV filling is dependent on diastolic suction. Right ventricle (RV) relaxation does not seem to contribute to atrial KE. Instead, RA KE generated during ventricular systole may be conserved in a hydraulic "flywheel" and transferred to the RV through helical flow, which may contribute to RV filling.

  20. 4D phase-contrast flow cardiovascular magnetic resonance: comprehensive quantification and visualization of flow dynamics in atrial septal defect and partial anomalous pulmonary venous return.

    PubMed

    Valverde, Israel; Simpson, John; Schaeffter, Tobias; Beerbaum, Philipp

    2010-11-01

    The case of an 8-year-old girl with atrial septal defect and associated anomalous pulmonary venous return is presented to illustrate the advantages of four dimensional flow (4D flow) over the current two dimensional flow (2D flow) in terms of time efficiency, easy planning, accurate and individual quantification of the blood sources contributing to the left-to-right shunting from one single acquisition, internal validation of flow measurement accuracy, possibility of reanalysis without rescanning in case of unexpected findings during the postprocessing, and comprehensive understanding of flow insight by use of particle tracing visualization.

  1. A prospective randomized study to assess the efficacy of rate and site of atrial pacing on long-term development of atrial fibrillation.

    PubMed

    Lau, Chu-Pak; Wang, Chun-Chieh; Ngarmukos, Tachapong; Kim, You-Ho; Kong, Chi-Woon; Omar, Razali; Sriratanasathavorn, Charn; Munawar, Muhammad; Kam, Ruth; Lee, Kathy Lf; Lau, Elizabeth Oi-Yan; Tse, Hung-Fat

    2009-09-01

    The Septal Pacing for Atrial Fibrillation Suppression Evaluation (SAFE) study is a single-blinded, parallel randomized designed multicenter study in pacemaker indicated patients with paroxysmal atrial fibrillation (AF). The objective is to evaluate whether the site of atrial pacing--conventional right atrial appendage versus low atrial septal--with or without atrial overdrive pacing will influence the development of persistent AF. The study will provide a definitive answer to whether a different atrial pacing site or the use of AF suppression pacing or both can give incremental antiarrhythmic benefit when one is implanting a device for a patient with a history of paroxysmal AF.

  2. Pulmonary venous flows reflect changes in left atrial hemodynamics during mitral balloon valvotomy

    NASA Technical Reports Server (NTRS)

    Yalcin, Fatih; El-Amrousy, Mahmoud; Muderrisoglu, Haldun; Korkmaz, Mehmet; Flachskampf, Frank; Tuzcu, Murat; Garcia, Mario G.; Thomas, James D.

    2002-01-01

    Patients with mitral stenosis have usually blunted pulmonary venous (PV) flow, because of decreased mitral valve area and diastolic dysfunction. The authors compared changes in Doppler PV velocities by using transesophageal echocardiography (TEE) against hemodynamics parameters before and after mitral balloon valvotomy to observe relevance of PV velocities and endsystolic left atrial (LA) pressure-volume relationship. In 25 patients (aged 35 +/- 17 years) with mitral stenosis in sinus rhythm, changes in LA pressure and volumes were compared with PV velocities before and after valvotomy. Mitral valve area, mitral gradients, and deceleration time were obtained. Mitral valve area and mitral gradients changed from 1 +/- 0.2 cm2 and 14.6 +/- 5.4 mmHg to 1.9 +/- 0.3 cm2 and 6.3 +/- 1.7 mmHg, respectively (p<0.001). AR peak reverse flow velocity and AR duration decreased from 29 +/- 13 cm/s and 110 =/- 30 msec to 19 +/- 6 cm/s and 80 +/- 29 msec respectively (p<0.001). Transmitral Doppler E wave deceleration time decreased from 327 +/- 85 to 209 +/- 61 s and cardiac output increased from 4.2 +/- 1.0 to 5.2 +/- 1.1 L/minute (p<0.001). The changes in LA pressure were correlated with changes in S/D (r=0.57, p<0.05). The changes in endsystolic LA pressure-volume relationship were also correlated with changes in S/D (r=0.52, p<0.05). Endsystolic LA pressure-volume relationship decreased after mitral balloon valvotomy, as a result of a large decrease in pressure. PV systolic/diastolic (S/D) waves ratio reflects endsystolic LA pressure-volume relationship and may be used as another indicator of successful valvotomy.

  3. Atrial Fibrillation

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Atrial Fibrillation? Atrial fibrillation (A-tre-al fi-bri-LA- ... Works article. Understanding the Electrical Problem in Atrial Fibrillation In AF, the heart's electrical signals don't ...

  4. Surgical Ablation of Atrial Fibrillation.

    PubMed

    Ramlawi, Basel; Abu Saleh, Walid K

    2015-01-01

    The Cox-maze procedure for the restoration of normal sinus rhythm, initially developed by Dr. James Cox, underwent several iterations over the years. The main concept consists of creating a series of transmural lesions in the right and left atria that disrupt re-entrant circuits responsible for propagating the abnormal atrial fibrillation rhythm. The left atrial appendage is excluded as a component of the Maze procedure. For the first three iterations of the Cox- maze procedure, these lesions were performed using a surgical cut-and-sew approach that ensured transmurality. The Cox-Maze IV is the most currently accepted iteration. It achieves the same lesion set of the Cox- maze III but uses alternative energy sources to create the transmural lesions, potentially in a minimally invasive approach on the beating heart. High-frequency ultrasound, microwave, and laser energy have all been used with varying success in the past. Today, bipolar radiofrequency heat or cryotherapy cooling are the most accepted sources for creating linear lesions with consistent safety and transmurality. The robust and reliable nature of these energy delivery methods has yielded a success rate reaching 90% freedom from atrial fibrillation at 12 months. Such approaches offer a significant long-term advantage over catheter-based ablation, especially in patients having longstanding, persistent atrial fibrillation with characteristics such as dilated left atrial dimensions, poor ejection fraction, and failed catheter ablation. Based on these improved results, there currently is significant interest in developing a hybrid ablation strategy that incorporates the superior transmural robust lesions of surgical ablation, the reliable stroke prevention potential of epicardial left atrial appendage exclusion, and sophisticated mapping and confirmatory catheter-based ablation technology. Such a minimally invasive hybrid strategy for ablation may lead to the development of multidisciplinary "Afib teams" to

  5. Pulmonary venous flow determinants of left atrial pressure under different loading conditions in a chronic animal model with mitral regurgitation

    NASA Technical Reports Server (NTRS)

    Yang, Hua; Jones, Michael; Shiota, Takahiro; Qin, Jian Xin; Kim, Yong Jin; Popovic, Zoran B.; Pu, Min; Greenberg, Neil L.; Cardon, Lisa A.; Eto, Yoko; Sitges, Marta; Zetts, Arthur D.; Thomas, James D.

    2002-01-01

    BACKGROUND: The aim of our study was to quantitatively compare the changes and correlations between pulmonary venous flow variables and mean left atrial pressure (mLAP) under different loading conditions in animals with chronic mitral regurgitation (MR) and without MR. METHODS: A total of 85 hemodynamic conditions were studied in 22 sheep, 12 without MR as control (NO-MR group) and 10 with MR (MR group). We obtained pulmonary venous flow systolic velocity (Sv) and diastolic velocity (Dv), Sv and Dv time integrals, their ratios (Sv/Dv and Sv/Dv time integral), mLAP, left ventricular end-diastolic pressure, and MR stroke volume. We also measured left atrial a, x, v, and y pressures and calculated the difference between v and y pressures. RESULTS: Average MR stroke volume was 10.6 +/- 4.3 mL/beat. There were good correlations between Sv (r = -0.64 and r = -0.59, P <.01), Sv/Dv (r = -0.62 and r = -0.74, P <.01), and mLAP in the MR and NO-MR groups, respectively. Correlations were also observed between Dv time integral (r = 0.61 and r = 0.57, P <.01) and left ventricular end-diastolic pressure in the MR and NO-MR groups. In velocity variables, Sv (r = -0.79, P <.001) was the best predictor of mLAP in both groups. The sensitivity and specificity of Sv = 0 in predicting mLAP 15 mm Hg or greater were 86% and 85%, respectively. CONCLUSION: Pulmonary venous flow variables correlated well with mLAP under altered loading conditions in the MR and NO-MR groups. They may be applied clinically as substitutes for invasively acquired indexes of mLAP to assess left atrial and left ventricular functional status.

  6. Appendages of the cyanobacterial cell.

    PubMed

    Schuergers, Nils; Wilde, Annegret

    2015-03-04

    Extracellular non-flagellar appendages, called pili or fimbriae, are widespread in gram-negative bacteria. They are involved in many different functions, including motility, adhesion, biofilm formation, and uptake of DNA. Sequencing data for a large number of cyanobacterial genomes revealed that most of them contain genes for pili synthesis. However, only for a very few cyanobacteria structure and function of these appendages have been analyzed. Here, we review the structure and function of type IV pili in Synechocystis sp. PCC 6803 and analyze the distribution of type IV pili associated genes in other cyanobacteria. Further, we discuss the role of the RNA-chaperone Hfq in pilus function and the presence of genes for the chaperone-usher pathway of pilus assembly in cyanobacteria.

  7. Specifying spacecraft flexible appendage rigidity

    NASA Technical Reports Server (NTRS)

    Seltzer, S. M.; Shelton, H. L.

    1977-01-01

    As a method for specifying the required degree of rigidity of spacecraft flexible appendages, an analytical technique is proposed for establishing values for the frequency, damping ratio, and modal gain (deflection) of the first several bending modes. The shortcomings of the technique result from the limitations associated with the order of the equations that can be handled practically. An iterative method is prescribed for handling a system whose structural flexibility is described by more than one normal mode. The analytical technique is applied to specifying solar panel rigidity constraints for the NASA Space Telescope. The traditional nonanalytic procedure for specifying the required degree of rigidity of spacecraft flexible appendages has been to set a lower limit below which bending mode frequencies may not lie.

  8. Passive control of a falling sphere by elliptic-shaped appendages

    NASA Astrophysics Data System (ADS)

    Lācis, Uǧis; Olivieri, Stefano; Mazzino, Andrea; Bagheri, Shervin

    2017-03-01

    The majority of investigations characterizing the motion of single or multiple particles in fluid flows consider canonical body shapes, such as spheres, cylinders, discs, etc. However, protrusions on bodies—either surface imperfections or appendages that serve a function—are ubiquitous in both nature and applications. In this work, we characterize how the dynamics of a sphere with an axis-symmetric wake is modified in the presence of thin three-dimensional elliptic-shaped protrusions. By investigating a wide range of three-dimensional appendages with different aspect ratios and lengths, we clearly show that the sphere with an appendage may robustly undergo an inverted-pendulum-like (IPL) instability. This means that the position of the appendage placed behind the sphere and aligned with the free-stream direction is unstable, similar to how an inverted pendulum is unstable under gravity. Due to this instability, nontrivial forces are generated on the body, leading to turn and drift, if the body is free to fall under gravity. Moreover, we identify the aspect ratio and length of the appendage that induces the largest side force on the sphere, and therefore also the largest drift for a freely falling body. Finally, we explain the physical mechanisms behind these observations in the context of the IPL instability, i.e., the balance between surface area of the appendage exposed to reversed flow in the wake and the surface area of the appendage exposed to fast free-stream flow.

  9. [Atrial fibrillation].

    PubMed

    Cárdenas, Manuel

    2007-01-01

    Atrial fibrillation is an arrhythmia characterized by no-coordinated atrial contraction that results in an inefficient atrial systole. The clinical classification of atrial fibrillation includes: ocassional, paroxysmal, persistent, and permanent. Multiple mechanisms have been described and accounts for a single ECG manifestation. Treatment should be individualized and has to considered several aspects including age, associated heart disease, and symptoms. Treatment strategies are: rhythm control, rate control, and thromboprophylaxis.

  10. Potential flow evaluation of the interference effect of strut-through-appendage-tip model mounting technique and reduction of the effect using blowing and suction

    NASA Astrophysics Data System (ADS)

    Mellish, Robert W.; Coder, David W.

    1988-11-01

    A parametric study based on incompressible, irrotational flow theory was conducted to evaluate the effect of strut support interference on the flow field about a model. The use of suction and blowing to correct the support interference is also investigated. Two struts were considered for numerical analysis, a small chord strut of constant cross section and a large chord strut of varying cross section, both attached to the tip of a model submarine sail. For the present study the SS N21 class and SSN 688 class sail geometries are utilized. To assess the level of strut interference, the presence fields on the surface of the sail and a flat representation of the hull were evaluated as follows. The flow field was computed for the model geometry without a strut attached (baseline configuration) and the results are compared with identical calculations for the model-strut combination. The calculated results are presented graphically as contour plots of the pressure coefficient (Cp). Contour plots of delta p (the difference between baseline ad sail-strut results) are utilized to identify regions of principal strut interference. Finally, suction and blowing was applied to minimize strut interference in areas considered important to hull boundary layer and sail flow that would affect wake measurements.

  11. Primary epiploic appendagitis: CT diagnosis.

    PubMed

    Sandrasegaran, Kumaresan; Maglinte, Dean D; Rajesh, Arumugam; Akisik, Fatih M

    2004-08-01

    The purpose of this study was to analyze the CT signs of primary epiploic appendagitis. A retrospective search of the CT database over 12 months for this diagnosis revealed 11 cases. The clinical findings were recorded. Softcopy CT images were reviewed by two experienced abdominal radiologists (KS, DM) for location of lesion, size, shape, presence of central hyperdense focus, degree of bowel wall thickening, mass effect, and ancillary signs. Abdominal pain was the primary symptom in all patients. Preliminary diagnoses were appendicitis (n=2), diverticulitis (n=5), pancreatitis (n=1), ovarian lesion (n=1), or unknown (n=2). Abdominal examination and white blood cell count were uninformative. CT examination revealed a solitary (n=11), ovoid (n=9) fatty lesion with some soft tissue stranding adjacent to the left colon (n=6), transverse colon (n=3), or right colon (n=2). Central hyperdensity (n=5), mild bowel wall thickening (n=2), and parietal peritoneal thickening (n=4) were also seen. In 4 patients the lesions were not visible on follow-up CT examination performed 23-184 days later. Primary epiploic appendagitis can clinically mimic other, more serious inflammatory conditions. Knowledge of its findings on CT would help the radiologist make the diagnosis and allow a more conservative approach to patient care.

  12. Hemolymph circulation in insect flight appendages: physiology of the wing heart and circulatory flow in the wings of the mosquito Anopheles gambiae.

    PubMed

    Chintapalli, Ravi Theja V; Hillyer, Julián F

    2016-12-15

    The wings of insects are composed of membranes supported by interconnected veins. Within these veins are epithelial cells, nerves and tracheae, and their maintenance requires the flow of hemolymph. For this purpose, insects employ accessory pulsatile organs (auxiliary hearts) that circulate hemolymph throughout the wings. Here, we used correlative approaches to determine the functional mechanics of hemolymph circulation in the wings of the malaria mosquito Anopheles gambiae Examination of sectioned tissues and intravital videos showed that the wing heart is located underneath the scutellum and is separate from the dorsal vessel. It is composed of a single pulsatile diaphragm (indicating that it is unpaired) that contracts at 3 Hz and circulates hemolymph throughout both wings. The wing heart contracts significantly faster than the dorsal vessel, and there is no correlation between the contractions of these two pulsatile organs. The wing heart functions by aspirating hemolymph out of the posterior wing veins, which forces hemolymph into the wings via anterior veins. By tracking the movement of fluorescent microspheres, we show that the flow diameter of the wing circulatory circuit is less than 1 µm, and we present a spatial map detailing the flow of hemolymph across all the wing veins, including the costa, sub-costa, ambient costa, radius, media, cubitus anterior, anal vein and crossveins. We also quantified the movement of hemolymph within the radius and within the ambient costa, and show that hemolymph velocity and maximum acceleration are higher when hemolymph is exiting the wing.

  13. Appendage mountable electronic devices conformable to surfaces

    DOEpatents

    Rogers, John; Ying, Ming; Bonifas, Andrew; Lu, Nanshu

    2017-01-24

    Disclosed are appendage mountable electronic systems and related methods for covering and conforming to an appendage surface. A flexible or stretchable substrate has an inner surface for receiving an appendage, including an appendage having a curved surface, and an opposed outer surface that is accessible to external surfaces. A stretchable or flexible electronic device is supported by the substrate inner and/or outer surface, depending on the application of interest. The electronic device in combination with the substrate provides a net bending stiffness to facilitate conformal contact between the inner surface and a surface of the appendage provided within the enclosure. In an aspect, the system is capable of surface flipping without adversely impacting electronic device functionality, such as electronic devices comprising arrays of sensors, actuators, or both sensors and actuators.

  14. Galectin-3 as a marker of interstitial atrial remodelling involved in atrial fibrillation

    PubMed Central

    Hernández-Romero, Diana; Vílchez, Juan Antonio; Lahoz, Álvaro; Romero-Aniorte, Ana I.; Jover, Eva; García-Alberola, Arcadio; Jara-Rubio, Rubén; Martínez, Carlos M.; Valdés, Mariano; Marín, Francisco

    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 with aortic valve or ischaemic heart diseases and 15 controls with permanent AF. Gal-3 levels were associated with sex, left atrial volume, previous cardiac disease, diabetes mellitus, hypertension, NYHA and NT-proBNP. We observed differences in serum Gal-3 concentrations between patients and controls with permanent AF (p = 0.020). We performed ROC curves related to fibrosis and established a cutoff point for Gal-3 >13.65 ng/ml. Multivariate analyses showed previous cardiac disease, NYHA scale and high Gal-3 to be independent predictors of fibrosis. After adjustment for confounding factors, atrial fibrosis remained the only independent factor for the development of AF (p = 0.022). High Gal-3 serum levels predict fibrosis of the atrial appendage. NYHA scale and previous cardiac disease were also associated with tissue fibrosis in patients undergoing surgery. Atrial fibrosis was the only independent predictor for post-operative AF occurrence in our model after correcting for confounding factors. PMID:28079145

  15. Sympathetic nerves in the mediation of renal response to localized stimulation of atrial receptors in anaesthetized dogs.

    PubMed Central

    Karim, F; Majid, D S; Summerill, R A

    1989-01-01

    1. Dogs were anaesthetized with chloralose and artificially ventilated. Localized stimulation of left atrial receptors for 23-25 min was achieved by distension of three small balloons at the pulmonary vein-atrial junctions and one in atrial appendage. Renal blood flows were measured by electromagnetic flow probes, glomerular filtration rate by creatinine clearance, urinary sodium excretion by flame photometry and solute excretion by osmometry. The mean aortic pressure was held constant at 92.2 +/- 2.4 mmHg (mean +/- S.E.M., n = 27) by means of a pressure bottle connected to the aorta and beta-adrenergic receptor activity was blocked by continuous infusion of propranolol (17 micrograms kg-1 min-1, I.V.). 2. In twelve dogs stimulation of left atrial receptors resulted in significant increases of 11.8 +/- 2.4% (P less than 0.001) in renal blood flow; 32.5 +/- 7.2% (P less than 0.001) in glomerular filtration rate; 19.5 +/- 5.0% (P less than 0.005) in filtration fraction: 36.3 +/- 9.0% (P less than 0.001) in urine flow: 32.7 +/- 9.2% (P less than 0.005) in sodium excretion: 36.6 +/- 9.9% (P less than 0.005) in osmolar excretion and a decrease of 31.3 +/- 11.2% (P less than 0.025) in free water clearance. Left atrial pressure and heart rate did not change significantly. In eight of the dogs ligation of the renal nerves resulted in similar changes in all of the renal variables; subsequent stimulation of atrial receptors did not cause significant changes in the renal variables. 3. In five additional dogs, in which heart rate and aortic pressure were allowed to change, stimulation of left atrial receptors for the same period resulted in significant increases in heart rate (4.3 +/- 0.7%. P less than 0.001) and mean aortic pressure (2.0 +/- 0.6%, P less than 0.025). Under this condition both the intact right kidneys and the denervated left kidneys showed significant responses in urine flow, sodium excretion, osmolar excretion and free water clearance. 4. The results show

  16. Atrial Fibrillation: Diagnosis

    MedlinePlus

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

  17. TRIF promotes angiotensin II-induced cross-talk between fibroblasts and macrophages in atrial fibrosis

    SciTech Connect

    Chen, Xiao-Qing; Zhang, Dao-Liang; Zhang, Ming-Jian; Guo, Meng; Zhan, Yang-Yang; Liu, Fang; Jiang, Wei-Feng; Zhou, Li; Zhao, Liang; Wang, Quan-Xing; Liu, Xu

    2015-08-14

    Aims: Atrial fibroblasts and macrophages have long been thought to participate in atrial fibrillation (AF). However, which specific mediator may regulate the interaction between them remains unclear. Methods and results: We provided the evidence for the involvement of Toll/IL-1 receptor domain-containing adaptor inducing IFN-β (TRIF), an important inflammation-related molecule, in the pathophysiology of AF. Patients with AF showed higher levels of angiotensin II (AngII) and TRIF expression and larger number of macrophages infiltration in left atria appendage than individuals with sinus rhythm (SR). In the cell study, AngII induced chemokines expressions in mouse atrial fibroblasts and AngII-stimulated atrial fibroblasts induced the chemotaxis of macrophages, which were reduced by losartan and TRIF siRNA. Meanwhile, AngII-stimulated atrial fibroblasts proliferation was enhanced by macrophages. Conclusions: Our data demonstrated that TRIF may be a crucial factor promoting the interaction between atrial fibroblasts and macrophages, leading to atrial fibrosis. - Highlights: • Compared with SR, AF showed higher TRIF expression in left atrial appendage. • TRIF siRNA reversed macrophage chemotaxis induced by AngII-treated fibroblast. • TRIF siRNA reversed chemokines expressions induced by AngII in fibroblast. • AngII-stimulated atrial fibroblast proliferation was enhanced by macrophage.

  18. Recurrent epiploic appendagitis mimicking appendicitis and cholecystitis

    PubMed Central

    Hearne, Christopher B.; Taboada, Jorge

    2017-01-01

    Epiploic appendagitis (EA) is a rare cause of acute abdominal pain caused by inflammation of an epiploic appendage. It has a nonspecific clinical presentation that may mimic other acute abdominal pathologies on physical exam, such as appendicitis, diverticulitis, or cholecystitis. However, EA is usually benign and self-limiting and can be treated conservatively. We present the case of a patient with two episodes of EA, the first mimicking acute appendicitis and the second mimicking acute cholecystitis. Although recurrence of EA is rare, it should be part of the differential diagnosis of acute, localized abdominal pain. A correct diagnosis of EA will prevent unnecessary hospitalization, antibiotic use, and surgical procedures. PMID:28127129

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

    PubMed Central

    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

  20. Inhibition of atrial receptor-induced renal responses by stimulation of carotid baroreceptors in anaesthetized dogs.

    PubMed Central

    Karim, F; Majid, D S

    1991-01-01

    1. Dogs were anaesthetized with chloralose and artificially ventilated. The receptors at three pulmonary vein-atrial junctions and in the left atrial appendage were stimulated by distension of small balloons. The carotid sinuses were vascularly isolated and perfused with arterial blood. A volume reservoir was connected to the aorta via the common carotid and femoral arteries to keep the mean aortic pressure constant (78.8 +/- 2.9 mmHg at low and 87.1 +/- 4.3 mmHg at high carotid sinus pressure, CSP). Propranolol and atropine were infused (i.v.) at 17 and 13 micrograms kg-1 min-1 respectively in order to block beta-adrenergic and cholinergic receptor activities. The renal blood flow was measured by an electromagnetic flow meter (wrap-round probe), glomerular filtration rate by creatinine clearance, urinary sodium excretion by flame photometry and osmolar excretion by osmometry. 2. In twelve tests in eight dogs, stimulation of the left atrial receptors for 13 min, at a mean CSP of 68.6 +/- 2.3 mmHg, resulted in significant increases in renal blood flow from 216 +/- 20.0 to 230 +/- 22.1 ml min-1 (100 g renal mass)-1 (P less than 0.005), glomerular filtration rate from 33.9 +/- 3.2 to 42.1 +/- 4.1 ml min-1 100 g-1 (P less than 0.005), filtration fraction from 0.23 +/- 0.02 to 0.26 +/- 0.02 (P less than 0.005), urine flow rate from 0.21 +/- 0.03 to 0.26 +/- 0.03 ml min-1 100 g-1 (P less than 0.001), sodium excretion from 12.9 +/- 4.0 to 16.4 +/- 4.8 mumol min-1 100 g-1 (P less than 0.01), osmolar excretion from 196 +/- 27.8 to 246 +/- 32.9 muosmol min-1 100 g-1 (P less than 0.005), whilst free water clearance decreased from -0.39 +/- 0.07 to -0.50 +/- 0.09 ml min-1 100 g-1 (P less than 0.005). However, the fractional excretion of sodium did not change. 3. In nine tests in seven dogs, stimulation of the left atrial receptors at a constantly high CSP (161 +/- 11.3 mmHg) did not produce significant change in any of the renal variables. 4. The results show that high level

  1. Primary Cardiac Sarcoidosis with Syncope and Refractory Atrial Arrhythmia: A Case Report and Review of the Literature

    PubMed Central

    Thangam, Manoj; Nathan, Sriram; Kar, Biswajit; Petrovic, Marija; Patel, Manish; Loyalka, Pranav; Buja, L. Maximilian

    2016-01-01

    We discuss the case of a 38-year-old black man who presented at our hospital with his first episode of syncope, recently developed atrial arrhythmias refractory to pharmacologic therapy, and a left atrial thrombus. He was diagnosed with primary cardiac sarcoidosis characterized by predominant involvement of the epicardium that caused atrial fibrillation and atrial flutter. Histologic analysis of his epicardial lesions yielded a diagnosis of sarcoidosis. This patient's atrial arrhythmia was successfully treated with a hybrid operation that involved resection of his atrial appendage, an Epicor maze procedure, and radiofrequency ablation during a catheter-based electrophysiologic study. The cardiac sarcoidosis was successfully managed with corticosteroid therapy. Our case report shows that sarcoidosis can initially manifest itself as syncope with new-onset atrial arrhythmia. Sarcoidosis is important in the differential diagnosis because of its progressive nature and its potential for treatment with pharmacologic, surgical, and catheter-based interventions. PMID:27303240

  2. [Successful treatment of atrial fibrillation by resection of a congenital aneurysm of the left heart atrium].

    PubMed

    Heigl, F; Steinbeck, G; Rienmüller, R; Kemkes, B M; Klinner, W

    1992-10-01

    Atrial fibrillation occurred in a 27-year-old patient with a history of globular cardiac enlargement since childhood. Because of the probable causal relationship between the preexisting heart disease-which was supposed to be an enlargement of the left atrium-and the rhythm disturbance, we recommended a surgical intervention. Cardiac surgery revealed a congenital aneurysm of the left atrial appendage which could be resected without any complication. Postoperatively, atrial fibrillation had returned to regular sinus rhythm. The bad prognosis with a high risk of systemic embolism is the reason why early cardiac surgery should be performed after diagnosis of this rare anomaly (20 reported cases) of the left atrium.

  3. Atrial Fibrillation: Treatment

    MedlinePlus

    ... 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 ...

  4. Atrial Fibrillation: Complications

    MedlinePlus

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

  5. Recent topics on the surgical treatment for atrial fibrillation.

    PubMed

    Misaki, Takuro; Fukahara, Kazuaki

    2004-10-01

    After the introduction of endocardial radiofrequency catheter, only two arrhythmias, atrial fibrillation and ischemic ventricular tachycardia require surgical procedures. In this review, we describe recent advancements and problems of surgical treatment for atrial fibrillation. On the basis of multiple-circuit re-entry theory, Cox developed the maze operation with the aim of interrupting the re-entry circuit. Although this procedure has become the gold standard technique for the surgical treatment of atrial fibrillation with approximately 90% success rate, several modifications have been made over time. To obtain a more physiological atrial transport function, radial approach technique or bilateral appendage-preserved maze procedures were developed and to simplify surgical procedures, maze operation with cryo-ablation or radiofrequency-ablation were created. Other topics are concerned with surgical target or approach to atrial fibrillation. Ectopic focus theories from pulmonary veins have been widely recognized recently and the surgical isolation of pulmonary veins orifices is performed with various energy sources. In addition to standard cut-and-sew surgical technique, cryoablation, unipolar or bipolar radiofrequency ablation, or microwave ablation were induced with endocardial or epicardial approach for the achievement of less invasive cardiac surgery. As atrial fibrillation leads to frequent mortality, cardiac surgeons have to treat atrial fibrillation with other cardiac disease more frequently to obtain better quality of operative results.

  6. Active damping of spacecraft structural appendage vibrations

    NASA Technical Reports Server (NTRS)

    Fedor, Joseph V. (Inventor)

    1990-01-01

    An active vibration damper system, for bending in two orthogonal directions and torsion, in each of three mutually perpendicular axes is located at the extremities of the flexible appendages of a space platform. The system components for each axis includes: an accelerometer, filtering and signal processing apparatus, and a DC motor-inertia wheel torquer. The motor torquer, when driven by a voltage proportional to the relative vibration tip velocity, produces a reaction torque for opposing and therefore damping a specific modal velocity of vibration. The relative tip velocity is obtained by integrating the difference between the signal output from the accelerometer located at the end of the appendage with the output of a usually carried accelerometer located on a relatively rigid body portion of the space platform. A selector switch, with sequential stepping logic or highest modal vibration energy logic, steps to another modal tip velocity channel and receives a signal voltage to damp another vibration mode. In this manner, several vibration modes can be damped with a single sensor/actuator pair. When a three axis damper is located on each of the major appendages of the platform, then all of the system vibration modes can be effectively damped.

  7. Low Energy Multi-Stage Atrial Defibrillation Therapy Terminates Atrial Fibrillation with Less Energy than a Single Shock

    PubMed Central

    Li, Wenwen; Janardhan, Ajit H.; Fedorov, Vadim V.; Sha, Qun; Schuessler, Richard B.; Efimov, Igor R.

    2011-01-01

    Background Implantable device therapy of atrial fibrillation (AF) is limited by pain from high-energy shocks. We developed a low-energy multi-stage defibrillation therapy and tested it in a canine model of AF. Methods and Results AF was induced by burst pacing during vagus nerve stimulation. Our novel defibrillation therapy consisted of three stages: ST1 (1-4 low energy biphasic shocks), ST2 (6-10 ultra-low energy monophasic shocks), and ST3 (anti-tachycardia pacing). Firstly, ST1 testing compared single or multiple monophasic (MP) and biphasic (BP) shocks. Secondly, several multi-stage therapies were tested: ST1 versus ST1+ST3 versus ST1+ST2+ST3. Thirdly, three shock vectors were compared: superior vena cava to distal coronary sinus (SVC>CSd), proximal coronary sinus to left atrial appendage (CSp>LAA) and right atrial appendage to left atrial appendage (RAA>LAA). The atrial defibrillation threshold (DFT) of 1BP shock was less than 1MP shock (0.55 ± 0.1 versus 1.38 ± 0.31 J; p =0.003). 2-3 BP shocks terminated AF with lower peak voltage than 1BP or 1MP shock and with lower atrial DFT than 4 BP shocks. Compared to ST1 therapy alone, ST1+ST3 lowered the atrial DFT moderately (0.51 ± 0.46 versus 0.95 ± 0.32 J; p = 0.036) while a three-stage therapy, ST1+ST2+ST3, dramatically lowered the atrial DFT (0.19 ± 0.12 J versus 0.95 ± 0.32 J for ST1 alone, p=0.0012). Finally, the three-stage therapy ST1+ST2+ST3 was equally effective for all studied vectors. Conclusions Three-stage electrotherapy significantly reduces the AF defibrillation threshold and opens the door to low energy atrial defibrillation at or below the pain threshold. PMID:21980076

  8. Atrial Fibrillation.

    PubMed

    Zimetbaum, Peter

    2017-03-07

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

  9. Atrial fibrillation pacing decreases intravascular shear stress in a New Zealand white rabbit model: implications in endothelial function.

    PubMed

    Jen, Nelson; Yu, Fei; Lee, Juhyun; Wasmund, Steve; Dai, Xiaohu; Chen, Christina; Chawareeyawong, Pai; Yang, Yongmo; Li, Rongsong; Hamdan, Mohamed H; Hsiai, Tzung K

    2013-08-01

    Atrial fibrillation (AF) is characterized by multiple rapid and irregular atrial depolarization, leading to rapid ventricular responses exceeding 100 beats per minute (bpm). We hypothesized that rapid and irregular pacing reduced intravascular shear stress (ISS) with implication to modulating endothelial responses. To simulate AF, we paced the left atrial appendage of New Zealand White rabbits (n = 4) at rapid and irregular intervals. Surface electrical cardiograms were recorded for atrial and ventricular rhythm, and intravascular convective heat transfer was measured by microthermal sensors, from which ISS was inferred. Rapid and irregular pacing decreased arterial systolic and diastolic pressures (baseline, 99/75 mmHg; rapid regular pacing, 92/73; rapid irregular pacing, 90/68; p < 0.001, n = 4), temporal gradients ([Formula: see text] from 1,275 ± 80 to 1,056 ± 180 dyne/cm(2) s), and reduced ISS (from baseline at 32.0 ± 2.4 to 22.7 ± 3.5 dyne/cm(2)). Computational fluid dynamics code demonstrated that experimentally inferred ISS provided a close approximation to the computed wall shear stress at a given catheter to vessel diameter ratio, shear stress range, and catheter position. In an in vitro flow system in which time-averaged shear stress was maintained at [Formula: see text] , we further demonstrated that rapid pulse rates at 150 bpm down-regulated endothelial nitric oxide, promoted superoxide (O 2 (.-) ) production, and increased monocyte binding to endothelial cells. These findings suggest that rapid pacing reduces ISS and [Formula: see text] , and rapid pulse rates modulate endothelial responses.

  10. Dynamics modeling and simulation of autonomous underwater vehicles with appendages

    NASA Astrophysics Data System (ADS)

    Su, Yumin; Zhao, Jinxin; Cao, Jian; Zhang, Guocheng

    2013-03-01

    To provide a simulation system platform for designing and debugging a small autonomous underwater vehicle's (AUV) motion controller, a six-degree of freedom (6-DOF) dynamic model for AUV controlled by thruster and fins with appendages is examined. Based on the dynamic model, a simulation system for the AUV's motion is established. The different kinds of typical motions are simulated to analyze the motion performance and the maneuverability of the AUV. In order to evaluate the influences of appendages on the motion performance of the AUV, simulations of the AUV with and without appendages are performed and compared. The results demonstrate the AUV has good maneuverability with and without appendages.

  11. Atrial fibrillation

    PubMed Central

    Munger, Thomas M.; Wu, Li-Qun; Shen, Win K.

    2014-01-01

    Atrial fibrillation is the most common arrhythmia affecting patients today. Disease prevalence is increasing at an alarming rate worldwide, and is associated with often catastrophic and costly consequences, including heart failure, syncope, dementia, and stroke. Therapies including anticoagulants, anti-arrhythmic medications, devices, and non-pharmacologic procedures in the last 30 years have improved patients' functionality with the disease. Nonetheless, it remains imperative that further research into AF epidemiology, genetics, detection, and treatments continues to push forward rapidly as the worldwide population ages dramatically over the next 20 years. PMID:24474959

  12. Hedgehog Signaling during Appendage Development and Regeneration

    PubMed Central

    Singh, Bhairab N.; Koyano-Nakagawa, Naoko; Donaldson, Andrew; Weaver, Cyprian V.; Garry, Mary G.; Garry, Daniel J.

    2015-01-01

    Regulatory networks that govern embryonic development have been well defined. While a common hypothesis supports the notion that the embryonic regulatory cascades are reexpressed following injury and tissue regeneration, the mechanistic regulatory pathways that mediate the regenerative response in higher organisms remain undefined. Relative to mammals, lower vertebrates, including zebrafish and newts, have a tremendous regenerative capacity to repair and regenerate a number of organs including: appendages, retina, heart, jaw and nervous system. Elucidation of the pathways that govern regeneration in these lower organisms may provide cues that will enhance the capacity for the regeneration of mammalian organs. Signaling pathways, such as the hedgehog pathway, have been shown to play critical functions during development and during regeneration in lower organisms. These signaling pathways have been shown to modulate multiple processes including cellular origin, positional identity and cellular maturation. The present review will focus on the cellular and molecular regulation of the hedgehog (HH) signaling pathway and its interaction with other signaling factors during appendage development and regeneration. PMID:26110318

  13. The Photogrammetric Appendage Structural Dynamics Experiment

    NASA Astrophysics Data System (ADS)

    Gilbert, Michael G.; Welch, Sharon S.; Moore, Christopher L.

    1995-09-01

    The Photogrammetric Appendage Structural Dynamics Experiment (PASDE) is a Hitchhiker payload scheduled to fly as part of the International Space Station (ISS) Phase-1 flight program to the Russian Space Station Mir. The objective of the first flight of PASDE on STS-74 is to obtain video images of the Mir Kvant-2 solar array response to various structural dynamic excitation events. This experiment will demonstrate the use of photogrammetric techniques for on-orbit structural dynamics measurements. Photogrammetric measurements will provide a low cost alternative to appendage mounted accelerometers to the ISS program. The PASDE experiment hardware consists of three instruments each containing two video cameras, two video tape recorders, a modified video signal time inserter, and associated avionics boxes. The instruments were designed and built at the NASA Langley Research Center, and are integrated into standard Hitchhiker canisters at the NASA Goddard Space Flight Center. The Hitchhiker canisters are then installed into the Space Shuttle cargo bay in locations selected to achieve good video coverage and photogrammetric geometry. The measurement resolution of the instruments is expected to be on the order of 0.25 cm (0.1 in.).

  14. The Photogrammetric Appendage Structural Dynamics Experiment

    NASA Technical Reports Server (NTRS)

    Gilbert, Michael G.; Welch, Sharon S.; Moore, Christopher L.

    1995-01-01

    The Photogrammetric Appendage Structural Dynamics Experiment (PASDE) is a Hitchhiker payload scheduled to fly as part of the International Space Station (ISS) Phase-1 flight program to the Russian Space Station Mir. The objective of the first flight of PASDE on STS-74 is to obtain video images of the Mir Kvant-2 solar array response to various structural dynamic excitation events. This experiment will demonstrate the use of photogrammetric techniques for on-orbit structural dynamics measurements. Photogrammetric measurements will provide a low cost alternative to appendage mounted accelerometers to the ISS program. The PASDE experiment hardware consists of three instruments each containing two video cameras, two video tape recorders, a modified video signal time inserter, and associated avionics boxes. The instruments were designed and built at the NASA Langley Research Center, and are integrated into standard Hitchhiker canisters at the NASA Goddard Space Flight Center. The Hitchhiker canisters are then installed into the Space Shuttle cargo bay in locations selected to achieve good video coverage and photogrammetric geometry. The measurement resolution of the instruments is expected to be on the order of 0.25 cm (0.1 in.).

  15. Comparison of diverse platelet activation markers as indicators for left atrial thrombus in atrial fibrillation.

    PubMed

    Tarnowski, Daniel; Poitz, David M; Plichta, Lina; Heidrich, Felix M; Wiedemann, Stephan; Ruf, Tobias; Mierke, Johannes; Löhn, Tobias; Jellinghaus, Stefanie; Strasser, Ruth H; Ibrahim, Karim; Pfluecke, Christian

    2017-03-13

    Atrial fibrillation (AF) is well known for being a major risk factor of thromboembolic stroke. We could recently demonstrate an association of monocyte-platelet aggregates (MPAs) with the degree of thrombogenicity in patients with AF. This study investigated platelet activation markers, as potential biomarkers for the presence of left atrial (LA) thrombus in patients with AF. One hundred and eight patients with symptomatic AF underwent transesophageal echocardiography (TEE) before scheduled cardioversion or pulmonary vein isolation. In order to determine the content of MPAs by flow-cytometric quantification analyses, blood was drawn on the day of TEE. The soluble CD40 Ligand (sCD40L) and soluble P-selectin (sP-selectin) were obtained by Cytometric Bead Arrays (CBA). D-dimer levels were detected by quantitative immunological determination of fibrin degradation products. Clinical, laboratory, and echocardiographic standard parameters were obtained from all patients, including the determination of the flow in the left atrial appendage (LAA). Patients with detected LA thrombus (n = 28) compared with patients without thrombus (n = 80) showed an increased number of common risk factors, such as age, diabetes, heart failure, and coronary artery disease (CAD). The presence of LA thrombus was associated with significantly increased levels of MPAs (147 ± 12 vs. 304 ± 29 per µl; p < 0.00), sCD40L (106.3 ± 31.0 vs. 33.5 ± 2.1 pg/ml, p = 0.027), and D-dimer (0.13 ± 0.02 vs. 0.69 ± 0.21 mg FEU/l, p = 0.015). In contrast, sP-selectin showed no association with LA thrombus. A multivariate regression analysis showed that MPAs, sCD40L as well as D-dimers were independent indicators for the existence of LA thrombus. MPAs above 170 cells/µl indicated LA thrombus with a high sensitivity of 93% and a specificity of 73% (OR 62, 95% CI. 6.9-557.2, p < 0.001) in patients with AF, whereas the D-dimer lost their quality as independent indicator by using the conventional cut-off of 0

  16. Some Practical Design Aspects of Appendages for Passenger Vessels

    NASA Astrophysics Data System (ADS)

    Jang, Hag Soo; Lee, Hwa Joon; Joo, Young Ryeol; Kim, Jung Joong; Chun, Ho Hwan

    2009-09-01

    The hydrodynamic effect of appendages for high-speed passenger vessels, such as Ro-Pax, Ro-Ro and cruiser vessels, is very severe and, therefore, it is essential to carry out the design of appendages for high-speed passenger vessels from the preliminary design stage to the final detail design stage through a full survey of the reference vessels together with sufficient technical investigation. Otherwise, many problems would be caused by mismatches between the appendages and the hull form. This paper investigates the design characteristics of some appendages, such as the side thruster, the shaft-strut, and the stern wedge, based on the design experience accumulated at Samsung, on CFD, and on model test results for high-speed passenger vessels. Further to this investigation, some practical and valuable design guidelines for such appendages are suggested.

  17. Relationship between Doppler transmitral flow velocity pattern and plasma atrial and brain natriuretic peptide concentrations in anuric patients on maintenance hemodialysis.

    PubMed

    Ito, Shigenori; Murai, Sumiko; Takada, Norio; Ozasa, Atsushi; Hanada, Mayumi; Sugiyama, Masaya; Suzuki, Kaoru; Nagae, Yuji; Inagaki, Toshiaki; Takeda, Yutaka; Fukutomi, Tatsuya; Joh, Takashi

    2006-05-01

    Plasma atrial (ANP) and brain (BNP) natriuretic peptide levels were compared to determine if transmitral flow velocity pattern is an instantaneous marker of body fluid balance in anuric patients on hemodialysis (HD). We measured plasma ANP and BNP levels and performed Doppler echocardiography in 38 anuric patients before and after HD. Patients with valvular disease, left ventricular systolic dysfunction having a fractional shortening < 0.3, arrhythmia, or left ventricular hypertrophy were excluded. The relationships between plasma ANP or BNP levels and the transmitral flow velocity pattern were evaluated. We also determined if the magnitude of the decrease in plasma ANP level was related to that in the early peak of transmitral flow velocity (peak E). The mean age of the subjects was 61.1 +/- 9.7 years. The ANP level of 213.6 +/- 146.1 pg/mL was related to peak E of 61 +/- 15 cm/s before HD (R = 0.504, P < 0.001), but not after HD. Plasma ANP level was not related to peak late transmitral flow velocity (peak A) or peak E/peak A before or after HD. BNP level was not related to the transmitral flow velocity pattern. The magnitude of decrease in hANP level during HD was significantly related to that in peak E (R = 0.342, P < 0.05). Before HD, peak E was related to the plasma ANP level, reflecting volume overload. Change in peak E showed a weak relationship with that of plasma ANP level in the same HD patient. The measurement of peak E during a HD session may potentially enable the assessment of hydration status during HD.

  18. Mosaic trisomy 13 and a sacral appendage

    PubMed Central

    Pachajoa, Harry; Meza Escobar, Luis Enrique

    2013-01-01

    Mosaic trisomy 13 occurs when there is a percentage of trisomic cells for an entire chromosome 13, while the remaining percentage of cells is euploid. The prevalence of this syndrome ranges from 1 in 10 000 to 1 in 20 000 births. Complete, partial or mosaic forms of this disorder can occur. The phenotype of mosaic trisomy 13 patients varies widely. Patients with mosaic trisomy 13 usually have a longer survival and a less severe phenotype compared to patients with complete trisomy 13. Genetic counselling is difficult due to the wide variation among the clinical manifestations of these patients. There have been 49 cases of mosaic trisomy 13 reported in the literature. We report the case of a patient with mosaic trisomy 13, a sacral appendage and a cleft lip and palate. PMID:23904413

  19. Mosaic trisomy 13 and a sacral appendage.

    PubMed

    Pachajoa, Harry; Meza Escobar, Luis Enrique

    2013-07-31

    Mosaic trisomy 13 occurs when there is a percentage of trisomic cells for an entire chromosome 13, while the remaining percentage of cells is euploid. The prevalence of this syndrome ranges from 1 in 10 000 to 1 in 20 000 births. Complete, partial or mosaic forms of this disorder can occur. The phenotype of mosaic trisomy 13 patients varies widely. Patients with mosaic trisomy 13 usually have a longer survival and a less severe phenotype compared to patients with complete trisomy 13. Genetic counselling is difficult due to the wide variation among the clinical manifestations of these patients. There have been 49 cases of mosaic trisomy 13 reported in the literature. We report the case of a patient with mosaic trisomy 13, a sacral appendage and a cleft lip and palate.

  20. [Secondary pulmonary embolism to right atrial myxoma].

    PubMed

    Vico Besó, L; Zúñiga Cedó, E

    2013-10-01

    A case of pulmonary thromboembolism secondary to atrial myxoma right. The myxoma is a primary cardiac tumor, namely, has his origin in the cardiac tissue. Primary cardiac tumors are rare, including myxomas, the most common type. Have a predilection for females and the most useful tool for diagnosis is echocardiography. About 75% of myxomas occur in the left atrium of the heart and rest are in the right atrium. Right atrial myxomas in some sometimes associated with tricuspid stenosis and atrial fibrillation. The most common clinical manifestations include symptoms of this neoplasm constitutional, and embolic phenomena resulting from the obstruction to the flow intracavitary. The treatment of this condition is surgical.

  1. Angiotensin II activates signal transducers and activators of transcription 3 via Rac1 in the atrial tissue in permanent atrial fibrillation patients with rheumatic heart disease.

    PubMed

    Xue, Xiao-Dong; Huang, Jian-Hua; Wang, Hui-Shan

    2015-01-01

    Patients with rheumatic heart disease (RHD) often experience persistent atrial fibrillation (AF) associated with adverse atrial structural remodeling (ASR) manifested by atrial fibrosis and left atrial enlargement. The aim of this study was to explore the potential molecular signaling mechanisms for atrial fibrosis and ASR. Twenty RHD patients with persistent AF and 10 RHD patients with sinus rhythm (Group A) were recruited in our study, which all underwent transthoracic echocardiography. Right atrial appendage (RAA) tissue samples were obtained from these patients during mitral/aortic valve replacement operation. The AF patients were further divided into two groups according to left atrial diameter (LAD): Group B with LAD ranging 50-65 mm and Group C with LAD >65 mm. Histological examinations were performed with hematoxylin-eosin staining and Masson's trichrome staining. Atrial angiotensin II (AngII) content was measured by ELISA. Rac1 and STAT3 protein levels were determined by Western blot analysis. Hematoxylin-eosin staining demonstrated highly organized arrangement of atrial muscles in control Group A and significant derangement in both Group B and C AF patients with reduced cell density and increased cell size. Moreover, Masson's trichrome staining showed that atrial myocytes were surrounded by large trunks of collagen fibers in both Group B and C, but not in Group A. There was a positive correlation between atrial tissue fibrosis and LAD. AngII content was markedly higher in Group C than in Group B than in Group A, which was positively correlated with LAD. Similarly, Rac1 and STAT3 protein levels were found considerably higher in Group C and B than in Group A with excellent correlation to LAD. Our study unraveled for the first time the AngII/Rac1/STAT3 signaling as a mechanism for ASR thereby AF in a particular clinical setting-RHD patients with persistent AF and indicated inhibition of this pathway may help ameliorating adverse ASR.

  2. Brain structure resolves the segmental affinity of anomalocaridid appendages.

    PubMed

    Cong, Peiyun; Ma, Xiaoya; Hou, Xianguang; Edgecombe, Gregory D; Strausfeld, Nicholas J

    2014-09-25

    Despite being among the most celebrated taxa from Cambrian biotas, anomalocaridids (order Radiodonta) have provoked intense debate about their affinities within the moulting-animal clade that includes Arthropoda. Current alternatives identify anomalocaridids as either stem-group euarthropods, crown-group euarthropods near the ancestry of chelicerates, or a segmented ecdysozoan lineage with convergent similarity to arthropods in appendage construction. Determining unambiguous affinities has been impeded by uncertainties about the segmental affiliation of anomalocaridid frontal appendages. These structures are variably homologized with jointed appendages of the second (deutocerebral) head segment, including antennae and 'great appendages' of Cambrian arthropods, or with the paired antenniform frontal appendages of living Onychophora and some Cambrian lobopodians. Here we describe Lyrarapax unguispinus, a new anomalocaridid from the early Cambrian Chengjiang biota, southwest China, nearly complete specimens of which preserve traces of muscles, digestive tract and brain. The traces of brain provide the first direct evidence for the segmental composition of the anomalocaridid head and its appendicular organization. Carbon-rich areas in the head resolve paired pre-protocerebral ganglia at the origin of paired frontal appendages. The ganglia connect to areas indicative of a bilateral pre-oral brain that receives projections from the eyestalk neuropils and compound retina. The dorsal, segmented brain of L. unguispinus reinforces an alliance between anomalocaridids and arthropods rather than cycloneuralians. Correspondences in brain organization between anomalocaridids and Onychophora resolve pre-protocerebral ganglia, associated with pre-ocular frontal appendages, as characters of the last common ancestor of euarthropods and onychophorans. A position of Radiodonta on the euarthropod stem-lineage implies the transformation of frontal appendages to another structure in crown

  3. What Is Atrial Fibrillation?

    MedlinePlus

    ANSWERS by heart Cardiovascular Conditions What Is Atrial Fibrillation? Your heart has a natural pacemaker, called the “ ... if the electric signals are normal. In atrial fibrillation (AFib), the heart’s two small upper chambers (atria) ...

  4. Caudal appendage derived from a vestigial remnant of the tailgut.

    PubMed

    Tatekawa, Yukihiro; Yamanaka, Hiroaki; Hasegawa, Toshimichi; Sonobe, Hiroshi

    2013-10-01

    The presence of smooth muscle at the basal portion of a caudal appendage is very rare. We report a 3-month-old girl in which a caudal appendage is associated with smooth muscle bundles at the perianal region. Immunohistochemistry was performed for NCAM (neural cell adhesion molecule) to identify smooth muscle. NCAM immunoreactivity was observed within the presumptive circular and/or longitudinal muscle layers of the muscularis propria. NCAM is expressed by smooth muscle during the early stages of human embryonic gut development, suggesting that the caudal appendage in the present case may be derived from a tailgut remnant.

  5. Relation of hs-CRP and BNP levels with the atrial spontaneous echo contrast and thrombi in permanent atrial fibrillation patients with different etiologies

    PubMed Central

    Sahin, Tayfun; Acar, Eser; Celikyurt, Umut; Kilic, Teoman; Kozdag, Guliz; Yilmaz, Irem; Agacdiken, Aysen; Ural, Dilek

    2012-01-01

    Summary Background Thromboembolic risk in permanent atrial fibrillation (AF) is strongly associated with the underlying etiology, and inflammatory parameters may contribute. The present study aimed to investigate the relationship of hs-CRP and BNP levels with left and right atrial appendage (LAA and RAA) function, presence of spontaneous echo contrast (SEC) and thrombus. Material/Methods Eighty-four permanent AF patients with different etiologies (20 mitral stenosis, 44 hypertension and 20 hyperthyroidism) and 23 patients with sinus rhythm were included. LAA and RAA flow velocities were measured by pulsed-wave Doppler and wall motion velocities with tissue Doppler imaging (TDI) in transesophageal echocardiography. Results Hs-CRP and BNP levels significantly differed among the 3 AF groups: levels were highest in mitral stenosis patients (8.6±5.3 mg/L and 98.0±125.7 pg/mL, respectively), the lowest hs-CRP was in hyperthyroidism patients (4.3±3.8 mg/L), and the lowest BNP was in hypertensive patients (64.8±44.3 pg/mL). There were also significant differences between the AF group and controls regarding hs-CRP and BNP levels. In the correlation analysis, BNP level was not significantly correlated with LAA and RAA functions, whereas hs-CRP level was significantly correlated with some LAA and RAA functions. On the other hand, hs-CRP level was significantly related to the presence of mild-moderate SEC and thrombi, mainly in mitral stenosis patients. Moreover, hs-CRP was the most important determinant of RAA thrombus formation, followed by RAA ejection fraction. In contrast, no positive or negative correlation was found between BNP levels and RAA and LAA thrombi. Conclusions Higher hs-CRP levels in AF patients may be a predictor for the presence of SEC and thrombi in the atria. PMID:22293881

  6. Managing atrial fibrillation in the very elderly patient: challenges and solutions

    PubMed Central

    Karamichalakis, Nikolaos; Letsas, Konstantinos P; Vlachos, Konstantinos; Georgopoulos, Stamatis; Bakalakos, Athanasios; Efremidis, Michael; Sideris, Antonios

    2015-01-01

    Atrial fibrillation (AF) is the most common arrhythmia affecting elderly patients. Management and treatment of AF in this rapidly growing population of older patients involve a comprehensive assessment that includes comorbidities, functional, and social status. The cornerstone in therapy of AF is thromboembolic protection. Anticoagulation therapy has evolved, using conventional or newer medications. Percutaneous left atrial appendage closure is a new invasive procedure evolving as an alternative to systematic anticoagulation therapy. Rate or rhythm control leads to relief in symptoms, fewer hospitalizations, and an improvement in quality of life. Invasive methods, such as catheter ablation, are the new frontier of treatment in maintaining an even sinus rhythm in this particular population. PMID:26604772

  7. Management of atrial fibrillation.

    PubMed

    Moukabary, Talal; Gonzalez, Mario D

    2015-07-01

    Atrial fibrillation is a very common clinical problem with a high prevalence that is expected to rise over time because of increasing risk factors (eg, age, obesity, hypertension). This high prevalence is also associated with high cost, because atrial fibrillation represents about 1% of overall health care spending. The management of atrial fibrillation involves multiple facets: (1) management of underlying disease if present and the management of atrial fibrillation risk factors, (2) prevention of thromboembolism, (3) control of the ventricular rate during atrial fibrillation, and (4) restoration and maintenance of normal sinus rhythm.

  8. A Silurian short-great-appendage arthropod

    PubMed Central

    Siveter, Derek J.; Briggs, Derek E. G.; Siveter, David J.; Sutton, Mark D.; Legg, David; Joomun, Sarah

    2014-01-01

    A new arthropod, Enalikter aphson gen. et sp. nov., is described from the Silurian (Wenlock Series) Herefordshire Lagerstätte of the UK. It belongs to the Megacheira (=short-great-appendage group), which is recognized here, for the first time, in strata younger than mid-Cambrian age. Discovery of this new Silurian taxon allows us to identify a Devonian megacheiran representative, Bundenbachiellus giganteus from the Hunsrück Slate of Germany. The phylogenetic position of megacheirans is controversial: they have been interpreted as stem chelicerates, or stem euarthropods, but when Enalikter and Bundenbachiellus are added to the most comprehensive morphological database available, a stem euarthropod position is supported. Enalikter represents the only fully three-dimensionally preserved stem-group euarthropod, it falls in the sister clade to the crown-group euarthropods, and it provides new insights surrounding the origin and early evolution of the euarthropods. Recognition of Enalikter and Bundenbachiellus as megacheirans indicates that this major arthropod group survived for nearly 100 Myr beyond the mid-Cambrian. PMID:24452026

  9. Epiploic appendagitis in a 27-year-old man

    PubMed Central

    Uehara, Ryohei; Isomoto, Hajime; Yamaguchi, Naoyuki; Ohnita, Ken; Fujita, Fumihiko; Ichikawa, Tatsuki; Takeshima, Fuminao; Yamaguchi, Tetsuji; Uetani, Masataka; Nakao, Kazuhiko

    2011-01-01

    Summary Background Epiploic appendagitis is an ischemic infarction of an epiploic appendage caused by torsion or spontaneous thrombosis of the central draining vein. Epiploic appendagitis is self-limited without surgery, and it is imperative for clinicians to be familiar with this entity. Case Report A healthy 27-year-old man was admitted due to acute right lower quadrant abdominal pain. Physical examination showed focal abdominal tenderness with slight rebound tenderness. Laboratory tests showed leukocytosis and an increased serum C-reactive protein level. Computed tomography (CT) showed a fatty ovoid pericolonic mass measuring 12 mm in diameter, with a circumferential hyperdense ring that abutted on the ascending colon and was surrounded by ill-defined fat stranding with a hyperdense ring. These findings were diagnostic of primary epiploic appendagitis. The patient was given high-dose antibiotics due to the secondary inflammation involving the parietal peritoneum. Conclusions Epiploic appendagitis presents with an abrupt onset of focal abdominal pain and tenderness without significant guarding or rigidity; it is an uncommon and difficult diagnosis. With awareness of this condition, however, evaluation by CT can provide an accurate diagnosis of epiploic appendagitis, distinguishing it from conditions with clinically overlapping manifestations. PMID:21959616

  10. How Is Atrial Fibrillation Treated?

    MedlinePlus

    ... from the NHLBI on Twitter. How Is Atrial Fibrillation Treated? Treatment for atrial fibrillation (AF) depends on ... much thyroid hormone). Who Needs Treatment for Atrial Fibrillation? People who have AF but don't have ...

  11. Surgical Ablation of Atrial Fibrillation during Mitral-Valve Surgery

    PubMed Central

    Gillinov, A. Marc; Gelijns, Annetine C.; Parides, Michael K.; DeRose, Joseph J.; Moskowitz, Alan J.; Voisine, Pierre; Ailawadi, Gorav; Bouchard, Denis; Smith, Peter K.; Mack, Michael J.; Acker, Michael A.; Mullen, John C.; Rose, Eric A.; Chang, Helena L.; Puskas, John D.; Couderc, Jean-Philippe; Gardner, Timothy J.; Varghese, Robin; Horvath, Keith A.; Bolling, Steven F.; Michler, Robert E.; Geller, Nancy L.; Ascheim, Deborah D.; Miller, Marissa A.; Bagiella, Emilia; Moquete, Ellen G.; Williams, Paula; Taddei-Peters, Wendy C.; O’Gara, Patrick T.; Blackstone, Eugene H.; Argenziano, Michael

    2015-01-01

    Background Among patients undergoing mitral-valve surgery, 30 to 50% present with atrial fibrillation, which is associated with reduced survival and increased risk of stroke. Surgical ablation of atrial fibrillation has been widely adopted, but evidence regarding its safety and effectiveness is limited. Methods We randomly assigned 260 patients with persistent or long-standing persistent atrial fibrillation who required mitral-valve surgery to undergo either surgical ablation (ablation group) or no ablation (control group) during the mitral-valve operation. Patients in the ablation group underwent further randomization to pulmonary-vein isolation or a biatrial maze procedure. All patients underwent closure of the left atrial appendage. The primary end point was freedom from atrial fibrillation at both 6 months and 12 months (as assessed by means of 3-day Holter monitoring). Results More patients in the ablation group than in the control group were free from atrial fibrillation at both 6 and 12 months (63.2% vs. 29.4%, P<0.001). There was no significant difference in the rate of freedom from atrial fibrillation between patients who underwent pulmonary-vein isolation and those who underwent the biatrial maze procedure (61.0% and 66.0%, respectively; P = 0.60). One-year mortality was 6.8% in the ablation group and 8.7% in the control group (hazard ratio with ablation, 0.76; 95% confidence interval, 0.32 to 1.84; P = 0.55). Ablation was associated with more implantations of a permanent pacemaker than was no ablation (21.5 vs. 8.1 per 100 patient-years, P = 0.01). There were no significant between-group differences in major cardiac or cerebrovascular adverse events, overall serious adverse events, or hospital readmissions. Conclusions The addition of atrial fibrillation ablation to mitral-valve surgery significantly increased the rate of freedom from atrial fibrillation at 1 year among patients with persistent or long-standing persistent atrial fibrillation, but the

  12. Organized Atrial Tachycardias after Atrial Fibrillation Ablation

    PubMed Central

    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

  13. Restoration of Atrial Mechanical Function after Successful Radio-Frequency Catheter Ablation of Atrial Flutter

    PubMed Central

    Rhee, Kyoung-Suk; Kang, Duk-Hyun; Song, Jae-Kwan; Nam, Gi-Byoung; Choi, Kee-Joon; Kim, You-Ho

    2001-01-01

    Background: Atrial mechanical dysfunction and its recovery time course after successful radiofrequency ablation of chronic atrial flutter (AFL) has been largely unknown. We serially evaluated left atrial function by echocardiography after successful ablation of chronic atrial flutter. Methods: In 13 patients with chronic AFL, mitral E wave A wave, and the ratio of A/E velocity were measured at 1 day, 1 month, 3 months and 6–12 months after successful radiofrequency (RF) ablation. Doppler tissue imaging (DTI) technique was also used to avoid load-dependent variation in the flow velocity pattern. Results: Left atrial mechanical function, assessed by A wave velocity and the annular motion, was depressed at 1 day, but improved significantly at 1 month and maintained through 6–12 months after the ablation. Left atrial size did not change significantly. Conclusion: Left atrial mechanical function was depressed immediately after successful RF ablation of chronic AFL, but it improved significantly after 1 month and was maintained over one year. PMID:11590904

  14. Atrial fibrillation - discharge

    MedlinePlus

    Auricular fibrillation - discharge; A-fib - discharge; AF - discharge; Afib - discharge ... been in the hospital because you have atrial fibrillation . This condition occurs when your heart beats faster ...

  15. Dynamic analysis of satellites with deployable hinged appendages

    NASA Technical Reports Server (NTRS)

    Oakes, Kevin F.

    1987-01-01

    The nonlinear equations of motion determining the planar dynamical behavior of an orbiting satellite deploying both one and two rigid appendages have been formulated using Lagrange's equations. The analysis accounts for large angle rotations, Coriolis effects, and the gravitational gradient, and the resulting coupled governing equations are integrated numerically. The analysis is applied to the Space Shuttle based deployment of rigid truss-like members, and results show that spacecraft inertia parameters, appendage mass and length, deployment velocity, and initial conditions all influence the system response. It is found that the resulting librational movement is related to the size of the deployment payload, and that gravitational forces lead to vehicle stabilization.

  16. Trends in hospitalization for atrial fibrillation: epidemiology, cost, and implications for the future.

    PubMed

    Sheikh, Azfar; Patel, Nileshkumar J; Nalluri, Nikhil; Agnihotri, Kanishk; Spagnola, Jonathan; Patel, Aashay; Asti, Deepak; Kanotra, Ritesh; Khan, Hafiz; Savani, Chirag; Arora, Shilpkumar; Patel, Nilay; Thakkar, Badal; Patel, Neil; Pau, Dhaval; Badheka, Apurva O; Deshmukh, Abhishek; Kowalski, Marcin; Viles-Gonzalez, Juan; Paydak, Hakan

    2015-01-01

    Atrial fibrillation (AF) is the most prevalent arrhythmia worldwide and the most common arrhythmia leading to hospitalization. Due to a substantial increase in incidence and prevalence of AF over the past few decades, it attributes to an extensive economic and public health burden. The increasing number of hospitalizations, aging population, anticoagulation management, and increasing trend for disposition to a skilled facility are drivers of the increasing cost associated with AF. There has been significant progress in AF management with the release of new oral anticoagulants, use of left atrial catheter ablation, and novel techniques for left atrial appendage closure. In this article, we aim to review the trends in epidemiology, hospitalization, and cost of AF along with its future implications on public health.

  17. Selected Disorders of Skin Appendages--Acne, Alopecia, Hyperhidrosis.

    PubMed

    Vary, Jay C

    2015-11-01

    This article reviewed some of the more common diseases of the skin appendages that are encountered in medicine: hyperhidrosis, acne, AA, FPHL, AGA, and TE. The pathophysiology behind the conditions and their treatments were discussed so that the clinician can make logical therapeutic choices for their affected patients.

  18. Effect of Low-level Vagus Nerve Stimulation on Cardiac Remodeling in a Rapid Atrial Pacing-induced Canine Model of Atrial Fibrillation.

    PubMed

    Lu, Yanmei; Sun, Juan; Zhou, Xianhui; Zhang, Ling; Ma, Mei; Tang, Baopeng

    2016-03-01

    The aim of this study was to establish a rapid atrial pacing-induced canine model of atrial fibrillation in studying the effects of low-level vagus nerve stimulation (LLVNS) on atrial fibrillation and the underlying mechanisms for those effects. Adult beagle dogs were randomly assigned to 3 groups: a sham operation group (sham group), a fast left atrial appendage 12-hour pacing group (pacing group), and a 12-hour pacing + LLVNS group (LLVNS group). All dogs underwent tests for their left and right atrial effective refractory period at various time points, after which they were killed, and samples of atrial and anterior right ganglionated plexi tissue were removed and microscopically examined. As pacing times increased, the mean effective refractory period in the pacing group became significantly shortened. The pacing group and the LLVNS group did show significant differences (P < 0.001). Three groups showed significant differences in their atrial myocardial periodic acid-Schiff-positive area staining densities. Anterior right ganglionated plexi expressions of nerve growth factor and neurturin (NRTN) in the sham group and the LLVNS group were lower than those in the pacing group (nerve growth factor in 3 groups were (36.35 ± 6.18) × 1000, (86.35 ± 5.63) × 1000, and (40.50 ± 7.24) × 1000 μm²/mm², P < 0.001; NRTN in 3 groups were (39.28 ± 7.80) × 1000, (80.24 ± 6.56) × 1000, (40.45 ± 6.97) × 1000 μm²/mm², P < 0.001). Therefore, LLVNS not only reverses the effect of fast pacing-induced atrial electrical remodeling in dogs but also exerts structural effects and stimulates remodeling of autonomic nerves.

  19. Left atrial strain: a new predictor of thrombotic risk and successful electrical cardioversion

    PubMed Central

    González-Alujas, Teresa; Valente, Filipa; Aranda, Carlos; Rodríguez-Palomares, José; Gutierrez, Laura; Maldonado, Giuliana; Galian, Laura; Teixidó, Gisela; Evangelista, Artur

    2016-01-01

    Background Left atrial deformation (LAD) parameters are new markers of atrial structural remodelling that seem to be affected in atrial fibrillation (AF) and atrial flutter (AFL). This study aimed to determine whether LAD can identify patients with a higher risk of thrombosis and unsuccessful electrical cardioversion (ECV). Methods Retrospective study including 56 patients with AF or AFL undergoing ECV, with previous transthoracic (TTE) and transoesophageal echocardiography (TEE) studies. Echocardiographic parameters analysed were as follows: left ventricle function, left atrium (LA) dimensions, LAD parameters (positive and negative strain peaks), left atrial appendage (LAA) filling and emptying velocities and the presence of thrombi. Strain values were analysed according to thrombotic risk and success of ECV. Results Lower mean values of peak-positive strain (PPS) in patients with prothrombotic velocities (<25 cm/s) and a higher incidence of thrombi in LAA were observed compared with those with normal velocities. Multivariate analysis revealed PPS normalised by LA maximum volume indexed by body surface area (BSA) to be associated with prothrombotic risk (odds ratio 0.000 (95% CI: 0.000–0.243), P 0.017), regardless of CHADs2VASC score. Peak-negative strain normalised by LA volumes indexed by BSA were associated with unsuccessful ECV. Conclusions Atrial deformation parameters identify AF and AFL patients with a high risk of thrombosis and unsuccessful ECV. Therefore, these new parameters should be included in anticoagulation management and rhythm vs rate control strategies. PMID:27249551

  20. Heat loss regulation: role of appendages and torso in the deer mouse and the white rabbit

    SciTech Connect

    Conley, K.E.; Porter, W.P.

    1985-01-01

    Thermal conductance was subdivided into the component conductances of the appendages and torso using a heat transfer analysis for the deer mouse, Peromyscus maniculatus, and the white rabbit, Oryctolagus cuniculus. The authors analysis was based on laboratory measurements of skin temperature and respiratory gas exchange made between air temperatures of 8 and 34/sup 0/C for the deer mouse, and from published data for the white rabbit. Two series conductances to heat transfer for each appendage and torso were evaluated: (1) internal (h/sub in/), for blood flow and tissue conduction to the skin surface, and (2) external (h/sub ex/), for heat loss from the skin surface to the environment. These two series conductances were represented in a single, total conductance (h/sub tot/). The limit to h/sub tot/ was set by h/sub ex/ and was reached by the torso h/sub tot/ of both animals. The increase in torso h/sub tot/ observed with air temperature for the mouse suggests that a pilomotor change in fur depth occurred. A control of h/sub tot/ below the limit set by h/sub ex/ was achieved by the h/sub in/ of each appendage. Elevation of mouse thermal conductance (C) resulted from increases in feet, tail, and torso h/sub tot/. In contrast, the rabbit showed no change in torso h/sub tot/ between 5 and 30/sup 0/C and ear h/sub tot/ exclusively increased C over these air temperatures. They suggest that the hyperthermia reported for the rabbit at 35/sup 0/C resulted from C reaching the physical limit set by torso and near h/sub ex/. Thus the ear alone adjusted rabbit C, whereas the feet, tail, and the torso contributed to the adjustment of mouse C.

  1. Surgery for Atrial Fibrillation.

    PubMed

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

    2016-04-01

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

  2. Surgery for atrial fibrillation.

    PubMed

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

    2014-11-01

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

  3. Atrial Fibrillation Medications

    MedlinePlus

    ... think you are pregnant If you notice red, dark brown or black urine or stools If you ... Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters • Understand your Risk for AFib Children • Symptoms of ...

  4. Induction of Atrial Fibrillation by Neutrophils Critically Depends on CD11b/CD18 Integrins

    PubMed Central

    Remane, Lisa; Mollenhauer, Martin; Rudolph, Volker; Rudolph, Tanja K.; Andrié, René P.; Stöckigt, Florian; Schrickel, Jan W.; Ravekes, Thorben; Deuschl, Florian; Nickenig, Georg; Willems, Stephan; Baldus, Stephan; Klinke, Anna

    2014-01-01

    Background Recent observational clinical and ex-vivo studies suggest that inflammation and in particular leukocyte activation predisposes to atrial fibrillation (AF). However, whether local binding and extravasation of leukocytes into atrial myocardium is an essential prerequisite for the initiation and propagation of AF remains elusive. Here we investigated the role of atrial CD11b/CD18 mediated infiltration of polymorphonuclear neutrophils (PMN) for the susceptibility to AF. Methods and Results C57bl/6J wildtype (WT) and CD11b/CD18 knock-out (CD11b−/−) mice were treated for 14 days with subcutaneous infusion of angiotensin II (Ang II), a known stimulus for PMN activation. Atria of Ang II-treated WT mice were characterized by increased PMN infiltration assessed in immunohistochemically stained sections. In contrast, atrial sections of CD11b−/− mice lacked a significant increase in PMN infiltration upon Ang II infusion. PMN infiltration was accompanied by profoundly enhanced atrial fibrosis in Ang II treated WT as compared to CD11b−/− mice. Upon in-vivo electrophysiological investigation, Ang II treatment significantly elevated the susceptibility for AF in WT mice if compared to vehicle treated animals given an increased number and increased duration of AF episodes. In contrast, animals deficient of CD11b/CD18 were entirely protected from AF induction. Likewise, epicardial activation mapping revealed decreased electrical conduction velocity in atria of Ang II treated WT mice, which was preserved in CD11b−/− mice. In addition, atrial PMN infiltration was enhanced in atrial appendage sections of patients with persistent AF as compared to patients without AF. Conclusions The current data critically link CD11b-integrin mediated atrial PMN infiltration to the formation of fibrosis, which promotes the initiation and propagation of AF. These findings not only reveal a mechanistic role of leukocytes in AF but also point towards a potential novel avenue of

  5. Simulation of the photogrammetric appendage structural dynamics experiment

    NASA Technical Reports Server (NTRS)

    Pappa, Richard S.; Gilbert, Michael G.; Welch, Sharon S.

    1995-01-01

    The Photogrammetric Appendage Structural Dynamics Experiment (PASDE) uses six video cameras in the Space Shuttle cargo bay to measure vibration of the Russian Mir space station Kvant-ll solar array. It occurs on Shuttle/Mir docking mission STS-74 scheduled for launch in November 1995. The objective of PASDE is to demonstrate photogrammetric technology for measuring 'untargeted' spacecraft appendage structural dynamics. This paper discusses a pre-flight simulation test conducted in July 1995, focusing on the image processing aspects. The flight camera system recorded vibrations of a full-scale structural test article having grids of white lines on black background, similar in appearance to the Mir solar array. Using image correlation analysis, line intersections on the structure are tracked in the video recordings to resolutions of less than 0.1 pixel. Calibration and merging of multiple camera views generated 3-dimensional displacements from which structural modal parameters are then obtained.

  6. Notch signaling and the determination of appendage identity

    PubMed Central

    Kurata, Shoichiro; Go, Masahiro J.; Artavanis-Tsakonas, Spyros; Gehring, Walter J.

    2000-01-01

    The Notch signaling pathway defines an evolutionarily conserved cell–cell interaction mechanism that throughout development controls the ability of precursor cells to respond to developmental signals. Here we show that Notch signaling regulates the expression of the master control genes eyeless, vestigial, and Distal-less, which in combination with homeotic genes induce the formation of eyes, wings, antennae, and legs. Therefore, Notch is involved in a common regulatory pathway for the determination of the various Drosophila appendages. PMID:10681430

  7. Attitude dynamic of spin-stabilized satellites with flexible appendages

    NASA Technical Reports Server (NTRS)

    Renard, M. L.

    1973-01-01

    Equations of motion and computer programs have been developed for analyzing the motion of a spin-stabilized spacecraft having long, flexible appendages. Stability charts were derived, or can be redrawn with the desired accuracy for any particular set of design parameters. Simulation graphs of variables of interest are readily obtainable on line using program FLEXAT. Finally, applications to actual satellites, such as UK-4 and IMP-1 have been considered.

  8. Recovery of atrial systolic function after pharmacological conversion of chronic atrial fibrillation to sinus rhythm: a Doppler echocardiographic study.

    PubMed Central

    Jović, A.; Troskot, R.

    1997-01-01

    OBJECTIVE: To evaluate the time course of the recovery of atrial mechanical function after pharmacological cardioversion of chronic atrial fibrillation to sinus rhythm. PATIENTS AND METHODS: 21 patients (12 male, 9 female, aged 37-77 years) with chronic atrial fibrillation (< 6 months) were followed up by serial transmitral pulsed Doppler echocardiography. Echocardiographic studies were performed within the first 24 hours and on day 8, 15, and 30 after cardioversion. RESULTS: There was a significant increase (mean (SD)) in the peak A-wave velocity (from 0.35 (0.10) on day 1 to 0.50 (1.73) on day 8, and thereafter a gradual increase to 0.61 (0.14) m/s on day 30). Similarly, integrated late atrial velocities increased from 4.50 (1.46) on day 1 to 5.61 (1.73) on day 8 and 5.97 (1.47) cm/s2 on day 30. The atrial contribution to total transmitral flow increased significantly from 26 (7)% immediately after conversion of atrial fibrillation to sinus rhythm to 34 (7)% on day 30, indicating the haemodynamic benefit of the restoration of sinus rhythm. Left atrial diameter decreased but not significantly, from 4.11 (0.37) to 3.98 (0.34) cm (P < 0.005). CONCLUSIONS: These results suggest that restoration of atrial mechanical function after pharmacological cardioversion in patients with chronic atrial fibrillation is slow and gradual, as it is after electrical DC restoration of sinus rhythm. This time course may have important implications for determining how long treatment with anticoagulants and antiarrhythmic agents needs to continue in individual patients. It will also influence the clinical assessment of the haemodynamic benefit of restoring sinus rhythm in patients with chronic atrial fibrillation. Images PMID:9038694

  9. Atrial fibrillation (acute onset)

    PubMed Central

    2014-01-01

    Introduction Acute atrial fibrillation is rapid, irregular, and chaotic atrial activity of recent onset. Various definitions of acute atrial fibrillation have been used in the literature, but for the purposes of this review we have included studies where atrial fibrillation may have occurred up to 7 days previously. Risk factors for acute atrial fibrillation include increasing age, cardiovascular disease, alcohol, diabetes, and lung disease. Acute atrial fibrillation increases the risk of stroke and heart failure. The condition resolves spontaneously within 24 to 48 hours in more than 50% of people; however, many people will require interventions to control heart rate or restore sinus rhythm. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions to prevent embolism, for conversion to sinus rhythm, and to control heart rate in people with recent-onset atrial fibrillation (within 7 days) who are haemodynamically stable? We searched: Medline, Embase, The Cochrane Library, and other important databases up to April 2014 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 26 studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review, we present information relating to the effectiveness and safety of the following interventions: amiodarone, antithrombotic treatment before cardioversion, atenolol, bisoprolol, carvedilol, digoxin, diltiazem, direct current cardioversion, flecainide, metoprolol, nebivolol, propafenone, sotalol, timolol, and verapamil. PMID:25430048

  10. Atrial Septal Defect (For Kids)

    MedlinePlus

    ... Dictionary of Medical Words En Español What Other Kids Are Reading Taking Care of Your Ears Taking ... an X-ray Atrial Septal Defect KidsHealth > For Kids > Atrial Septal Defect Print A A A What's ...

  11. Can Atrial Fibrillation Be Prevented?

    MedlinePlus

    ... from the NHLBI on Twitter. How Can Atrial Fibrillation Be Prevented? Following a healthy lifestyle and taking ... for heart disease may help you prevent atrial fibrillation (AF). These steps include: Following a heart healthy ...

  12. Stroke Prevention in Atrial Fibrillation

    MedlinePlus

    ... Association Cardiology Patient Page Stroke Prevention in Atrial Fibrillation Christian T. Ruff Download PDF https://doi.org/ ... an irregular and fast heartbeat. What Causes Atrial Fibrillation? Several factors and medical conditions make it more ...

  13. Kodymirus and the case for convergence of raptorial appendages in Cambrian arthropods.

    PubMed

    Lamsdell, James C; Stein, Martin; Selden, Paul A

    2013-09-01

    Kodymirus vagans Chlupáč and Havlíček in Sb Geol Ved Paleontol 6:7-20, 1965 is redescribed as an aglaspidid-like arthropod bearing a single pair of enlarged raptorial appendages, which are shown to be the second cephalic appendage. A number of early Palaeozoic arthropods, recognized from predominantly Cambrian Konservat-Lagerstätten, are known to have borne single pairs of large raptorial appendages. They are well established for the iconic yet problematic anomalocarids, the common megacheirans, and the ubiquitous bivalved Isoxys. Further taxa, such as fuxianhuiids and Branchiocaris, have been reported to have single pairs of specialized cephalic appendages, i.e., appendages differentiated from a largely homonomous limbs series, members of which act in metachronal motion. The homology of these raptorial appendages across these Cambrian arthropods has often been assumed, despite differences in morphology. Thus, anomalocaridids, for instance, have long multiarticulate "frontal appendages" consisting of many articles bearing an armature of paired serial spines, while megacheirans and Isoxys have short "great appendages" consisting of few articles with well-developed endites or elongate fingers. Homology of these appendages would require them to belong to the same cephalic segment. We argue based on morphological evidence that, to the contrary, the raptorial appendages of some of these taxa can be shown to belong to different cephalic segments and are the result of convergence in life habits. K. vagans is yet another important example for this, representing an instance for this morphology from a marginal marine environment.

  14. In search of the Golden Fleece: unraveling principles of morphogenesis by studying the integrative biology of skin appendages.

    PubMed

    Hughes, Michael W; Wu, Ping; Jiang, Ting-Xin; Lin, Sung-Jan; Dong, Chen-Yuan; Li, Ang; Hsieh, Fon-Jou; Widelitz, Randall B; Chuong, Cheng Ming

    2011-04-01

    The mythological story of the Golden Fleece symbolizes the magical regenerative power of skin appendages. Similar to the adventurous pursuit of the Golden Fleece by the multi-talented Argonauts, today we also need an integrated multi-disciplined approach to understand the cellular and molecular processes during development, regeneration and evolution of skin appendages. To this end, we have explored several aspects of skin appendage biology that contribute to the Turing activator/inhibitor model in feather pattern formation, the topo-biological arrangement of stem cells in organ shape determination, the macro-environmental regulation of stem cells in regenerative hair waves, and potential novel molecular pathways in the morphological evolution of feathers. Here we show our current integrative biology efforts to unravel the complex cellular behavior in patterning stem cells and the control of regional specificity in skin appendages. We use feather/scale tissue recombination to demonstrate the timing control of competence and inducibility. Feathers from different body regions are used to study skin regional specificity. Bioinformatic analyses of transcriptome microarrays show the potential involvement of candidate molecular pathways. We further show Hox genes exhibit some region specific expression patterns. To visualize real time events, we applied time-lapse movies, confocal microscopy and multiphoton microscopy to analyze the morphogenesis of cultured embryonic chicken skin explants. These modern imaging technologies reveal unexpectedly complex cellular flow and organization of extracellular matrix molecules in three dimensions. While these approaches are in preliminary stages, this perspective highlights the challenges we face and new integrative tools we will use. Future work will follow these leads to develop a systems biology view and understanding in the morphogenetic principles that govern the development and regeneration of ectodermal organs.

  15. In search of the Golden Fleece: Unraveling principles of morphogenesis by studying the integrative biology of skin appendages

    PubMed Central

    Hughes, Michael W.; Wu, Ping; Jiang, Ting-Xin; Lin, Sung-Jan; Dong, Chen-Yuan; Li, Ang; Hsieh, Fon-Jou; Widelitz, Randall B.; Choung, Cheng Ming

    2013-01-01

    Summary The mythological story of the Golden Fleece symbolizes the magical regenerative power of skin appendages. Similar to the adventurous pursuit of the Golden Fleece by the multi-talented Argonauts, today we also need an integrated multi-disciplined approach to understand the cellular and molecular processes during development, regeneration and evolution of skin appendages. To this end, we have explored several aspects of skin appendage biology that contribute to the Turing activator / inhibitor model in feather pattern formation, the topo-biological arrangement of stem cells in organ shape determination, the macro-environmental regulation of stem cells in regenerative hair waves, and potential novel molecular pathways in the morphological evolution of feathers. Here we show our current integrative biology efforts to unravel the complex cellular behavior in patterning stem cells and the control of regional specificity in skin appendages. We use feather / scale tissue recombination to demonstrate the timing control of competence and inducibility. Feathers from different body regions are used to study skin regional specificity. Bioinformatic analyses of transcriptome microarrays show the potential involvement of candidate molecular pathways. We further show Hox genes exhibit some region specific expression patterns. To visualize real time events, we applied time-lapse movies, confocal microscopy and multiphoton microscopy to analyze the morphogenesis of cultured embryonic chicken skin explants. These modern imaging technologies reveal unexpectedly complex cellular flow and organization of extracellular matrix molecules in three dimensions. While these approaches are in preliminary stages, this perspective highlights the challenges we face and new integrative tools we will use. Future work will follow these leads to develop a systems biology view and understanding in the morphogenetic principles that govern the development and regeneration of ectodermal organs

  16. Right coronary artery perforation by an active-fixation atrial pacing lead resulting in life-threatening tamponade.

    PubMed

    Nakagawa, Eiichiro; Abe, Yukio; Komatsu, Ryushi; Naruko, Takahiko; Itoh, Akira

    2015-10-01

    Cardiac tamponade resulting from perforation of a cardiac chamber is a relatively rare complication of pacemaker implantation. We report the first case of perforation of the right coronary artery related to the implantation of a screw-in atrial pacing lead, presenting as life-threatening cardiac tamponade. We report the case of a 72-year-old woman with complete atrioventricular block and dyspnea on exertion. A permanent pacemaker was implanted with bipolar Medtronic active-fixation leads positioned in the right atrial appendage and at the right ventricular basal septum without any difficulty. Approximately 3.5 h after the procedure, the patient complained of nausea, and the systolic blood pressure decreased to less than 60 mmHg. Echocardiography revealed a large pericardial effusion. Because the effects of pericardiocentesis lasted for less than an hour, the patient underwent a thoracotomy. After evacuation of a massive hemopericardium, bright red blood was seen gushing out from the right coronary artery, which was located on the opposite site of the right atrial appendage where a small portion of the screw tip was observed to be penetrating the atrial wall. The right coronary artery perforation was repaired using autologous pericardium-reinforced 7-0 prolene mattress sutures. Perforation of the right coronary artery is a potential complication and should be part of the differential diagnosis of cardiac tamponade after pacemaker implantation.

  17. Right coronary artery perforation by an active-fixation atrial pacing lead resulting in life-threatening tamponade

    PubMed Central

    Nakagawa, Eiichiro; Abe, Yukio; Komatsu, Ryushi; Naruko, Takahiko; Itoh, Akira

    2015-01-01

    Cardiac tamponade resulting from perforation of a cardiac chamber is a relatively rare complication of pacemaker implantation. We report the first case of perforation of the right coronary artery related to the implantation of a screw-in atrial pacing lead, presenting as life-threatening cardiac tamponade. We report the case of a 72-year-old woman with complete atrioventricular block and dyspnea on exertion. A permanent pacemaker was implanted with bipolar Medtronic active-fixation leads positioned in the right atrial appendage and at the right ventricular basal septum without any difficulty. Approximately 3.5 h after the procedure, the patient complained of nausea, and the systolic blood pressure decreased to less than 60 mmHg. Echocardiography revealed a large pericardial effusion. Because the effects of pericardiocentesis lasted for less than an hour, the patient underwent a thoracotomy. After evacuation of a massive hemopericardium, bright red blood was seen gushing out from the right coronary artery, which was located on the opposite site of the right atrial appendage where a small portion of the screw tip was observed to be penetrating the atrial wall. The right coronary artery perforation was repaired using autologous pericardium-reinforced 7-0 prolene mattress sutures. Perforation of the right coronary artery is a potential complication and should be part of the differential diagnosis of cardiac tamponade after pacemaker implantation. PMID:26550089

  18. Loss of atrial contractility is primary cause of atrial dilatation during first days of atrial fibrillation.

    PubMed

    Schotten, Ulrich; de Haan, Sunniva; Neuberger, Hans-Ruprecht; Eijsbouts, Sabine; Blaauw, Yuri; Tieleman, Robert; Allessie, Maurits

    2004-11-01

    Atrial fibrillation (AF) induces a progressive dilatation of the atria which in turn might promote the arrhythmia. The mechanism of atrial dilatation during AF is not known. To test the hypothesis that loss of atrial contractile function is a primary cause of atrial dilatation during the first days of AF, eight goats were chronically instrumented with epicardial electrodes, a pressure transducer in the right atrium, and piezoelectric crystals to measure right atrial diameter. AF was induced with the use of repetitive burst pacing. Atrial contractility was assessed during sinus rhythm, atrial pacing (160-, 300-, and 400-ms cycle length), and electrically induced AF. The compliance of the fibrillating right atrium was measured during unloading the atria with diuretics and loading with 1 liter of saline. All measurements were repeated after 6, 12, and 24 h of AF and then once a day during the first 5 days of AF. Recovery of the observed changes after spontaneous cardioversion was also studied. After 5 days of AF, atrial contractility during sinus rhythm or slow atrial pacing was greatly reduced. During rapid pacing (160 ms) or AF, the amplitude of the atrial pressure waves had declined to 20% of control. The compliance of the fibrillating atria increased twofold, whereas the right atrial pressure was unchanged. As a result, the mean right atrial diameter increased by approximately 12%. All changes were reversible within 3 days of sinus rhythm. We conclude that atrial dilatation during the first days of AF is due to an increase in atrial compliance caused by loss of atrial contractility during AF. Atrial compliance and size are restored when atrial contractility recovers after cardioversion of AF.

  19. Principles of appendage design in robots and animals determining terradynamic performance on flowable ground.

    PubMed

    Qian, Feifei; Zhang, Tingnan; Korff, Wyatt; Umbanhowar, Paul B; Full, Robert J; Goldman, Daniel I

    2015-10-08

    Natural substrates like sand, soil, leaf litter and snow vary widely in penetration resistance. To search for principles of appendage design in robots and animals that permit high performance on such flowable ground, we developed a ground control technique by which the penetration resistance of a dry granular substrate could be widely and rapidly varied. The approach was embodied in a device consisting of an air fluidized bed trackway in which a gentle upward flow of air through the granular material resulted in a decreased penetration resistance. As the volumetric air flow, Q, increased to the fluidization transition, the penetration resistance decreased to zero. Using a bio-inspired hexapedal robot as a physical model, we systematically studied how locomotor performance (average forward speed, v(x)) varied with ground penetration resistance and robot leg frequency. Average robot speed decreased with increasing Q, and decreased more rapidly for increasing leg frequency, ω. A universal scaling model revealed that the leg penetration ratio (foot pressure relative to penetration force per unit area per depth and leg length) determined v(x) for all ground penetration resistances and robot leg frequencies. To extend our result to include continuous variation of locomotor foot pressure, we used a resistive force theory based terradynamic approach to perform numerical simulations. The terradynamic model successfully predicted locomotor performance for low resistance granular states. Despite variation in morphology and gait, the performance of running lizards, geckos and crabs on flowable ground was also influenced by the leg penetration ratio. In summary, appendage designs which reduce foot pressure can passively maintain minimal leg penetration ratio as the ground weakens, and consequently permits maintenance of effective locomotion over a range of terradynamically challenging surfaces.

  20. Artificial helical microswimmers with mastigoneme-inspired appendages

    PubMed Central

    Tottori, Soichiro; Nelson, Bradley J.

    2013-01-01

    A smooth flagellum moves in the opposite direction of the propagation of flagellar waves. Conversely, a flagellum covered with appendages perpendicular to the main flagellum, called mastigonemes, moves in the same direction as the propagation of flagellar waves. Inspired by mastigoneme structures in nature, we report the reversal of the swimming direction of magnetically actuated artificial helical microswimmers. The main flagella and mastigonemes of these microswimmers are fabricated together using three-dimensional lithography and electron beam evaporation of ferromagnetic thin films. The results show that the swimming speed and direction can be controlled by changing the length/spacing ratio of the mastigonemes. PMID:24396533

  1. Exploiting periodicity to extract the atrial activity in atrial arrhythmias

    NASA Astrophysics Data System (ADS)

    Llinares, Raul; Igual, Jorge

    2011-12-01

    Atrial fibrillation disorders are one of the main arrhythmias of the elderly. The atrial and ventricular activities are decoupled during an atrial fibrillation episode, and very rapid and irregular waves replace the usual atrial P-wave in a normal sinus rhythm electrocardiogram (ECG). The estimation of these wavelets is a must for clinical analysis. We propose a new approach to this problem focused on the quasiperiodicity of these wavelets. Atrial activity is characterized by a main atrial rhythm in the interval 3-12 Hz. It enables us to establish the problem as the separation of the original sources from the instantaneous linear combination of them recorded in the ECG or the extraction of only the atrial component exploiting the quasiperiodic feature of the atrial signal. This methodology implies the previous estimation of such main atrial period. We present two algorithms that separate and extract the atrial rhythm starting from a prior estimation of the main atrial frequency. The first one is an algebraic method based on the maximization of a cost function that measures the periodicity. The other one is an adaptive algorithm that exploits the decorrelation of the atrial and other signals diagonalizing the correlation matrices at multiple lags of the period of atrial activity. The algorithms are applied successfully to synthetic and real data. In simulated ECGs, the average correlation index obtained was 0.811 and 0.847, respectively. In real ECGs, the accuracy of the results was validated using spectral and temporal parameters. The average peak frequency and spectral concentration obtained were 5.550 and 5.554 Hz and 56.3 and 54.4%, respectively, and the kurtosis was 0.266 and 0.695. For validation purposes, we compared the proposed algorithms with established methods, obtaining better results for simulated and real registers.

  2. Surgery for Atrial Fibrillation

    PubMed Central

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

    2015-01-01

    Synopsis Atrial fibrillation is the most common cardiac arrhythmia and its treatment options include drug therapy or, catheter-based or surgical interventions. The surgical treatment of atrial fibrillation has undergone multiple evolutions over the last several decades. The Cox-Maze procedure which was developed by James Cox in 1987 is a procedure where multiple surgical incisions are created along the atria to interrupt the electrical pathways thought to allow atrial fibrillation to persist. This procedure went on to become the gold standard for the surgical treatment of atrial fibrillation and is currently in its 4th iteration called the Cox-Maze IV. The Cox-Maze IV replaced the previous “cut-and-sew” method with a combination of cryoablation and bipolar RF ablation. The adaption of ablation technologies allowed the Cox-Maze IV procedure to be performed through a less invasive right minithoracotomy instead of a traditional sternotomy approach. The aim of this article is to review the indications and preoperative planning for performing a Cox-Maze IV procedure. A description of the operative techniques for both a sternotomy and right mini-thoracotomy approach will be discussed in addition to specific postoperative considerations. Finally, this article will review the literature describing the surgical results for both approaches including comparisons of the Cox-Maze IV to the previous “cut-and-sew” method. PMID:25443237

  3. Posterior left atrial wall hematoma mimicking cystic intracavitary atrial mass.

    PubMed

    Bahnacy, Yasser; Suresh, Cheriyil; Dawoud, Hamed; Zubaid, Mohammad

    2010-10-01

    Atrial myxoma is the most common benign primary tumor of the heart most commonly in the left atrium (LA). Cystic or cavitated intracardiac masses are rare. We report the case of a 43-year-old male patient admitted with chest infection, hemoptysis, and severe respiratory distress, who had to be ventilated. Chest computed tomography showed bilateral lung consolidation with large mass occupying the region of the LA. Transthoracic echocardiography and transesophageal echocardiography showed a large intracavitary left atrial cystic mobile mass. Open-heart surgical exploration did not show any mass inside the LA. A posterior left atrial wall hematoma was found and evacuated. Biopsies confirmed the presence of blood clots. Posterior left atrial wall hematoma may appear as left atrial intracavitary cystic mass and should be included in the differential diagnosis of cystic left atrial mass.

  4. Genetics Home Reference: familial atrial fibrillation

    MedlinePlus

    ... Home Health Conditions familial atrial fibrillation familial atrial fibrillation Enable Javascript to view the expand/collapse boxes. ... PDF Open All Close All Description Familial atrial fibrillation is an inherited condition that disrupts the heart's ...

  5. A new atrial septostomy technique.

    PubMed

    Park, S C; Zuberbuhler, J R; Neches, W H; Lenox, C C; Zoltun, R A

    1975-01-01

    Balloon atrial septostomy is usually ineffective if the atrial septum is thickened. A technique for incising the atrial septum is described. A no. 6 French catheter was modified to enclose a tiny surgical blade. The distal end of the blade was pivoted to the catheter tip, and the proximal end was attached to a guide wire in the catheter lumen. Advancing the guide wire protruded the blade through a slit in the long axis of the tip of the catheter. Atrial septostomy was performed in five newborn lambs in vivo and in adult dog hearts and human hearts in vitro by advancing the catheter tip across the atrial septum with the blade retracted and withdrawing it to the right atrium with the blade extended. Eight to 12 mm lacerations of the atrial septum were produced and could be extended by subsequent balloon septostomy. The technique may be useful when balloon septostomy has been ineffective.

  6. Ebstein Anomaly With Right Atrial Clot

    PubMed Central

    Kumar, Prakash; Singhal, Gaurav; Sinha, Santosh Kumar; Pandey, Umeshwar; Thakur, Ramesh; Varma, Chandra Mohan

    2015-01-01

    Ebstein anomaly (EA) is a rare congenital malformation of the tricuspid valve (TV), often associated with other cardiac malformations, especially atrial septal defect/patent foramen ovale (PFO) which is present in 80-90% of patients and predisposes to paradoxical embolization. We describe the case of a 17-year-old female, who presented with worsening exertional dyspnea, fatigue and pedal edema and atrial fibrillation (AF). Transthoracic echocardiography showed EA with severely dilated right atrium (RA), small functional right ventricle (RV), low velocity flow across TV with spontaneous echo contrast and giant clot in RA. Fortunately for the patient, contrast and transesophageal echocardiography revealed an intact interatrial septum with no PFO preventing any paradoxical embolism from large clot in RA, more so in the background of AF. Important differential diagnosis of congenitally unguarded TV orifice was ruled out due to presence of septal and anterior leaflets of TV and associated chordae. PMID:28197250

  7. Ebstein Anomaly With Right Atrial Clot.

    PubMed

    Kumar, Prakash; Singhal, Gaurav; Sinha, Santosh Kumar; Pandey, Umeshwar; Thakur, Ramesh; Varma, Chandra Mohan

    2015-10-01

    Ebstein anomaly (EA) is a rare congenital malformation of the tricuspid valve (TV), often associated with other cardiac malformations, especially atrial septal defect/patent foramen ovale (PFO) which is present in 80-90% of patients and predisposes to paradoxical embolization. We describe the case of a 17-year-old female, who presented with worsening exertional dyspnea, fatigue and pedal edema and atrial fibrillation (AF). Transthoracic echocardiography showed EA with severely dilated right atrium (RA), small functional right ventricle (RV), low velocity flow across TV with spontaneous echo contrast and giant clot in RA. Fortunately for the patient, contrast and transesophageal echocardiography revealed an intact interatrial septum with no PFO preventing any paradoxical embolism from large clot in RA, more so in the background of AF. Important differential diagnosis of congenitally unguarded TV orifice was ruled out due to presence of septal and anterior leaflets of TV and associated chordae.

  8. Attitude dynamics simulation subroutines for systems of hinge-connected rigid bodies with nonrigid appendages

    NASA Technical Reports Server (NTRS)

    Fleischer, G. E.; Likins, P. W.

    1975-01-01

    Three computer subroutines designed to solve the vector-dyadic differential equations of rotational motion for systems that may be idealized as a collection of hinge-connected rigid bodies assembled in a tree topology, with an optional flexible appendage attached to each body are reported. Deformations of the appendages are mathematically represented by modal coordinates and are assumed small. Within these constraints, the subroutines provide equation solutions for (1) the most general case of unrestricted hinge rotations, with appendage base bodies nominally rotating at a constant speed, (2) the case of unrestricted hinge rotations between rigid bodies, with the restriction that those rigid bodies carrying appendages are nominally nonspinning, and (3) the case of small hinge rotations and nominally nonrotating appendages. Sample problems and their solutions are presented to illustrate the utility of the computer programs.

  9. Convergent evolutionary reduction of atrial septation in lungless salamanders.

    PubMed

    Lewis, Zachary R; Hanken, James

    2017-01-01

    Nearly two thirds of the approximately 700 species of living salamanders are lungless. These species respire entirely through the skin and buccopharyngeal mucosa. Lung loss dramatically impacts the configuration of the circulatory system but the effects of evolutionary lung loss on cardiac morphology have long been controversial. For example, there is presumably little need for an atrial septum in lungless salamanders due to the absence of pulmonary veins and the presence of a single source of mixed blood flowing into the heart, but whether lungless salamanders possess an atrial septum and whether the sinoatrial aperture is located in the left or right atrium are unresolved; authors have stated opposing claims since the late 1800s. Here, we use micro-computed tomography (μ-CT) imaging, gross dissection and histological reconstruction to compare cardiac morphology among lungless plethodontid salamanders (Plethodontidae), salamanders with lungs, and the convergently lungless species Onychodactylus japonicus (Hynobiidae). Plethodontid salamanders have partial atrial septa and incomplete separation of the atrium into left and right halves. Partial septation is also seen in O. japonicus. Hence, lungless salamanders from two lineages convergently evolved similar morphology of the atrial septum. The partial septum in lungless salamanders can make it appear that the sinoatrial aperture is in the left atrium, but this interpretation is incorrect. Outgroup comparisons demonstrate that the aperture is located in a posterodorsal extension of the right atrium into the left side of the heart. Independent evolutionary losses of the atrial septum may have a similar developmental basis. In mammals, the lungs induce formation of the atrial septum by secreting morphogens to neighboring mesenchyme. We hypothesize that the lungs induce atrial septum development in amphibians in a similar fashion to mammals, and that atrial septum reduction in lungless salamanders is a direct result

  10. Stroke prevention following modified endoscopic ablation and appendectomy for atrial fibrillation.

    PubMed

    Ma, Nan; Jiang, Zhaolei; Chen, Fei; Yin, Hang; Ding, Fangbao; Mei, Ju

    2016-09-01

    We reported the results of stroke prevention following modified endoscopic procedure for atrial fibrillation. 82 patients underwent modified endoscopic procedure for atrial fibrillation (AF), in whom 47 had paroxysmal, 28 had persistent, and 7 had long-standing atrial fibrillation. CHA2DS2VASC median score was 3 (range from 0 to 8). The procedure was performed on the beating heart, through 3 ports on the left chest wall. Pulmonary vein isolation and ablation of the left atrium were achieved by bipolar radiofrequency ablation. Left atrial appendage (LAA) was excluded by stapler. Brain CT, cardiac CT and 24-h Holter monitoring were performed following the procedure. The procedure was successfully completed for all patients. The mean duration was 122 ± 40.1 min. LAA was excluded after appendectomy and checked by intraoperative transesophageal echocardiography. The mean follow-up duration was 24.3 ± 3.5 months. No patients showed signs and symptoms of transient ischemic attack or stroke. No new positive findings were demonstrated by recurring brain CT scan performed after the procedure. Cardiac CT confirmed the absence of LAA and thrombosis in the left atrium. 87.8 % (72/82) of all patients were in sinus rhythm. Our results demonstrate that the modified endoscopic procedure is a safe, effective, and appropriate treatment for AF, which restores sinus rhythm and may be associated with the prevention of AF-related stroke.

  11. A conserved genetic mechanism specifies deutocerebral appendage identity in insects and arachnids

    PubMed Central

    Sharma, Prashant P.; Tarazona, Oscar A.; Lopez, Davys H.; Schwager, Evelyn E.; Cohn, Martin J.; Wheeler, Ward C.; Extavour, Cassandra G.

    2015-01-01

    The segmental architecture of the arthropod head is one of the most controversial topics in the evolutionary developmental biology of arthropods. The deutocerebral (second) segment of the head is putatively homologous across Arthropoda, as inferred from the segmental distribution of the tripartite brain and the absence of Hox gene expression of this anterior-most, appendage-bearing segment. While this homology statement implies a putative common mechanism for differentiation of deutocerebral appendages across arthropods, experimental data for deutocerebral appendage fate specification are limited to winged insects. Mandibulates (hexapods, crustaceans and myriapods) bear a characteristic pair of antennae on the deutocerebral segment, whereas chelicerates (e.g. spiders, scorpions, harvestmen) bear the eponymous chelicerae. In such hexapods as the fruit fly, Drosophila melanogaster, and the cricket, Gryllus bimaculatus, cephalic appendages are differentiated from the thoracic appendages (legs) by the activity of the appendage patterning gene homothorax (hth). Here we show that embryonic RNA interference against hth in the harvestman Phalangium opilio results in homeonotic chelicera-to-leg transformations, and also in some cases pedipalp-to-leg transformations. In more strongly affected embryos, adjacent appendages undergo fusion and/or truncation, and legs display proximal defects, suggesting conservation of additional functions of hth in patterning the antero-posterior and proximo-distal appendage axes. Expression signal of anterior Hox genes labial, proboscipedia and Deformed is diminished, but not absent, in hth RNAi embryos, consistent with results previously obtained with the insect G. bimaculatus. Our results substantiate a deep homology across arthropods of the mechanism whereby cephalic appendages are differentiated from locomotory appendages. PMID:25948691

  12. A conserved genetic mechanism specifies deutocerebral appendage identity in insects and arachnids.

    PubMed

    Sharma, Prashant P; Tarazona, Oscar A; Lopez, Davys H; Schwager, Evelyn E; Cohn, Martin J; Wheeler, Ward C; Extavour, Cassandra G

    2015-06-07

    The segmental architecture of the arthropod head is one of the most controversial topics in the evolutionary developmental biology of arthropods. The deutocerebral (second) segment of the head is putatively homologous across Arthropoda, as inferred from the segmental distribution of the tripartite brain and the absence of Hox gene expression of this anterior-most, appendage-bearing segment. While this homology statement implies a putative common mechanism for differentiation of deutocerebral appendages across arthropods, experimental data for deutocerebral appendage fate specification are limited to winged insects. Mandibulates (hexapods, crustaceans and myriapods) bear a characteristic pair of antennae on the deutocerebral segment, whereas chelicerates (e.g. spiders, scorpions, harvestmen) bear the eponymous chelicerae. In such hexapods as the fruit fly, Drosophila melanogaster, and the cricket, Gryllus bimaculatus, cephalic appendages are differentiated from the thoracic appendages (legs) by the activity of the appendage patterning gene homothorax (hth). Here we show that embryonic RNA interference against hth in the harvestman Phalangium opilio results in homeonotic chelicera-to-leg transformations, and also in some cases pedipalp-to-leg transformations. In more strongly affected embryos, adjacent appendages undergo fusion and/or truncation, and legs display proximal defects, suggesting conservation of additional functions of hth in patterning the antero-posterior and proximo-distal appendage axes. Expression signal of anterior Hox genes labial, proboscipedia and Deformed is diminished, but not absent, in hth RNAi embryos, consistent with results previously obtained with the insect G. bimaculatus. Our results substantiate a deep homology across arthropods of the mechanism whereby cephalic appendages are differentiated from locomotory appendages.

  13. Atrial fibrillation in the elderly

    PubMed Central

    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

  14. Leaf epidermal appendages of desert plant: an ecological perspective

    NASA Astrophysics Data System (ADS)

    Liu, Yubing; Li, Xinrong; Li, Mengmeng

    2014-05-01

    Desert plant often have few, tiny or no leaves, which reduces transpiration. The epidermis of their leaves is often ornamented outgrowths called trichomes or hairs and a thick waxy cuticle. Hairs on the leaf surface trap humidity in dry climates and waxy leaf surfaces reduce water loss. Our present study is to investigate the characteristics of trichomes and waxy cuticle in leaf surface of desert plant, which in the long term acclimation in semi-humid, semi-arid and arid ecosystems of Northern China, from east (Zhangwu county, Liaoning province) to west (Korla city, Xinjiang Uygur Autonomous Region), passing through several provinces including the Inner Mongolia Autonomous Region, Shanxi province, the Ningxia Hui Autonomous Region and Gansu province. 68 shrubs and 7 trees were selected in the natural habitats which were artificial sand fixing vegetation and the adjacent natural vegetation in sandy areas. The leaf epidermis was observed by scanning electron microscopy (SEM) and the cuticle thickness was calculated in the leaf cross-section by transmission electron microscopy (TEM). The results indicated that the epidermis of selected materials was divided into five categories: (1) Trichomes with different forms covered completely on the adaxial and abaxial surfaces of leaf, and any other epidermal appendages could not been observed. (2) Epicuticular wax crystals with different forms almost completely covered in the epistomatal chambers as well as on the surrounding epidermis, and there were no other appendages on the leaf surface. (3) A lot of warty hairs arranged neatly on the surface and the stomatal index was too low. (4) Several or even dozens of papillary epidermal cells covered with waxy crystals enclosed a sunken stomata chamber, therefore the stomatal density is very low. (5) Like ordinary terrestrial plants, epidermal cells and cell outline are clear, with epidermal hairs or not, and the stomata and waxy crystals are visible. TEM showed that desert plants

  15. The atrial natriuretic factor.

    PubMed Central

    Genest, J

    1986-01-01

    In less than three years since the rapid and potent natriuretic response to intravenous injection of atrial myocardial extract in rats was reported the factor responsible for the diuretic, natriuretic, and vasodilating activity of the atrial homogenates was isolated, its chemical structure elucidated, and its total synthesis achieved. Also the cDNA and the gene encoding for the atrial natriuretic factor in mice, rats, and man have been cloned and the chromosomal site identified. The major effects of this hormone are vasodilatation, prevention and inhibition of the contraction induced by noradrenaline and angiotensin II, diuresis, and natriuresis associated in most instances with a pronounced increase in glomerular filtration rate and filtration fraction, inhibition of aldosterone secretion, and considerable stimulation of particulate guanylate cyclase activity. High density specific binding sites have been demonstrated in the zona glomerulosa of the adrenal cortex, in the renal glomeruli, and in the collecting ducts, and in the brain areas involved in the regulation of blood pressure and of sodium and water (AV3V region, subfornical organ, nucleus tractus solitarius, area postrema). Images Fig 1 Fig 5 PMID:2945572

  16. Centriole distal appendages promote membrane docking, leading to cilia initiation

    PubMed Central

    Tanos, Barbara E.; Yang, Hui-Ju; Soni, Rajesh; Wang, Won-Jing; Macaluso, Frank P.; Asara, John M.; Tsou, Meng-Fu Bryan

    2013-01-01

    The distal appendages (DAPs) of centrioles have been proposed to anchor cilia to the plasma membrane, but their molecular composition, assembly, and exact function in ciliogenesis remain poorly understood. Using quantitative centrosome proteomics and superresolution microscopy, we identified five DAP components, including one previously described (CEP164), one partially characterized (CEP89 [ccdc123]), and three novel (CEP83 [ccdc41], SCLT1, and FBF1) DAP proteins. Analyses of DAP assembly revealed a hierarchy. CEP83 recruits both SCLT1 and CEP89 to centrioles. Subsequent recruitment of FBF1 and CEP164 is independent of CEP89 but mediated by SCLT1. All five DAP components are essential for ciliogenesis; loss of CEP83 specifically blocks centriole-to-membrane docking. Undocked centrioles fail to recruit TTBK2 or release CP110, the two earliest modifications found on centrioles prior to cilia assembly, revealing centriole-to-membrane docking as a temporal and spatial cue promoting cilia initiation. PMID:23348840

  17. Dissimilar Pain of Primary Epiploic Appendagitis and Malabsorption

    PubMed Central

    Enko, Dietmar; Wallner-Liebmann, Sandra J; Lackner, Sonja; Mangge, Harald

    2017-01-01

    Primary Epiploic Appendagitis (PEA) is a rare cause of acute or subacute abdominal complaints and non-migratory pain. Usually the diagnosis of PEA is made when Computed Tomography (CT) reveals characteristic figures. Nonspecific abdominal complaints including diffuse abdominal pain may be caused by carbohydrate and/or protein malabsorption. We report a case of a patient with PEA who recovered without medication or surgical treatment within a few days. Eight months later, he was diagnosed with lactose- and histamine malabsorption and Helicobacter pylori infection. The malabsorption was treated successfully with an individually-tailored diet free of culprit triggers and the Helicobacter pylori infection was eradicated. A localized non-migratory abdominal pain caused by PEA needs to be differentiated from nonspecific abdominal complaints due to malabsorption and Helicobacter pylori infection. PMID:28384920

  18. Evo-Devo of Amniote Integuments and Appendages

    PubMed Central

    Wu, Ping; Hou, Lianhai; Plikus, Maksim; Hughes, Michael; Scehnet, Jeffrey; Suksaweang, Sanong; Widelitz, Randall B.; Jiang, Ting-Xin; Chuong, Cheng-Ming

    2015-01-01

    Integuments form the boundary between an organism and the environment. The evolution of novel developmental mechanisms in integuments and appendages allows animals to live in diverse ecological environments. Here we focus on amniotes. The major achievement for reptile skin is an adaptation to the land with the formation of a successful barrier. The stratum corneum enables this barrier to prevent water loss from the skin and allowed amphibian/reptile ancestors to go onto the land. Overlapping scales and production of β-keratins provide strong protection. Epidermal invagination led to the formation of avian feather and mammalian hair follicles in the dermis. Both adopted a proximal - distal growth mode that maintains endothermy. Feathers form hierarchical branches which produce the vane that makes flight possible. Recent discoveries of feathered dinosaurs in China inspire new thinking on the origin of feathers. In the laboratory, epithelial - mesenchymal recombinations and molecular mis-expressions were carried out to test the plasticity of epithelial organ formation. We review the work on the transformation of scales into feathers, conversion between barbs and rachis, and the production of “chicken teeth”. In mammals, tilting the balance of the BMP pathway in K14 noggin transgenic mice alters the number, size and phenotypes of different ectodermal organs, making investigators rethink the distinction between morpho-regulation and pathological changes. Models on the evolution of feathers and hairs from reptile integuments are discussed. A hypothetical Evo-Devo space where diverse integument appendages can be placed according to complex phenotypes and novel developmental mechanisms is presented. PMID:15272390

  19. Homology of arthropod anterior appendages revealed by Hox gene expression in a sea spider.

    PubMed

    Jager, Muriel; Murienne, Jérôme; Clabaut, Céline; Deutsch, Jean; Le Guyader, Hervé; Manuel, Michaël

    2006-05-25

    Arthropod head segments offer a paradigm for understanding the diversification of form during evolution, as a variety of morphologically diverse appendages have arisen from them. There has been long-running controversy, however, concerning which head appendages are homologous among arthropods, and from which ancestral arrangement they have been derived. This controversy has recently been rekindled by the proposition that the probable ancestral arrangement, with appendages on the first head segment, has not been lost in all extant arthropods as previously thought, but has been retained in the pycnogonids, or sea spiders. This proposal was based on the neuroanatomical analysis of larvae from the sea spider Anoplodactylus sp., and suggested that the most anterior pair of appendages, the chelifores, are innervated from the first part of the brain, the protocerebrum. Our examination of Hox gene expression in another sea spider, Endeis spinosa, refutes this hypothesis. The anterior boundaries of Hox gene expression domains place the chelifore appendages as clearly belonging to the second head segment, innervated from the second part of the brain, the deutocerebrum. The deutocerebrum must have been secondarily displaced towards the protocerebrum in pycnogonid ancestors. As anterior-most appendages are also deutocerebral in the other two arthropod groups, the Euchelicerata and the Mandibulata, we conclude that the protocerebral appendages have been lost in all extant arthropods.

  20. Characterization of a novel Bacillus thuringiensis phenotype possessing multiple appendages attached to a parasporal body.

    PubMed

    Ventura-Suárez, Antonio; Cruz-Camarillo, Ramón; Rampersad, Joanne; Ammons, David R; López-Villegas, Edgar O; Ibarra, Jorge E; Rojas-Avelizapa, Luz I

    2011-01-01

    Bacillus thuringiensis is a bacterium best known for its production of crystal-like bodies comprised of one or more Cry-proteins, which can be toxic to insects, nematodes or cancer cells. Although strains of B. thuringiensis have occasionally been observed with filamentous appendages attached to their spores, appendages in association with their parasporal bodies are extremely rare. Herein we report the characterization of Bt1-88, a bacterial strain isolated from the Caribbean that produces a spore-crystal complex containing six long appendages, each comprised of numerous thinner filaments approximately 10 nm in diameter and 2.5 μm in length. Each of the multi-filament appendages was attached to a single, small parasporal body located at one end of the bacterial spore. Biochemical tests, 16S rDNA gene sequencing, and the identification of two Cry proteins by partial protein sequencing (putatively Cry1A and Cry2A), unambiguously identified Bt1-88 as a strain of B. thuringiensis. Bt1-88 represents the second reported strain of B. thuringiensis possessing a parasporal body/appendage phenotype characterized by one or more long appendages, comprised of numerous filaments in association with a parasporal body. This finding suggests that Bt1-88 is a member of a new phenotypic class of B. thuringiensis, in which the parasporal body may perform a novel structural role through its association with multi-filament appendages.

  1. NRG™ RF powered transseptal needle: a useful technique for transcatheter atrial septostomy and Fontan fenestration: report of three cases

    PubMed Central

    Karagöz, Tevfik; Akin, Alper; Aykan, Hayrettin Hakan

    2014-01-01

    Transseptal puncture (TSP) is a frequently performed procedure for gaining access to the left atrium for catheter ablation, hemodynamic assessment of the left heart, left ventricular assist device implantation, percutaneous left atrial appendage closure or mitral valvuloplasty during childhood and adulthood. The standard technique for transseptal puncture applies mechanical pressure on the fossa ovalis with a Brockenbrough needle. However, this method is not feasible when the fossa ovalis is thick and aneurysmatic. In such patients, the radiofrequency ablation energy systems can be offered as a better alternative for TSP. Here, we aimed to demonstrate the outcome of transseptal puncture performed with an NRG™ RF powered transseptal needle in three patients. PMID:25428681

  2. Atrial Cardiopathy: A Broadened Concept of Left Atrial Thromboembolism Beyond Atrial Fibrillation

    PubMed Central

    Kamel, Hooman; Okin, Peter M.; Longstreth, W. T.; Elkind, Mitchell S.V.; Soliman, Elsayed Z.

    2016-01-01

    Atrial fibrillation (AF) has long been associated with a heightened risk of ischemic stroke and systemic thromboembolism, but recent data require a re-evaluation of our understanding of the nature of this relationship. New findings about the temporal connection between AF and stroke, alongside evidence linking markers of left atrial abnormalities with stroke in the absence of apparent AF, suggest that left atrial thromboembolism may occur even without AF. These observations undermine the hypothesis that the dysrhythmia that defines AF is necessary and sufficient to cause thromboembolism. In this commentary, we instead suggest that the substrate for thromboembolism may often be the anatomic and physiological atrial derangements associated with AF. Therefore, our understanding of cardioembolic stroke may be more complete if we shift our representation of its origin from AF to the concept of atrial cardiopathy. PMID:26021638

  3. The effect on the efferent vagal nerves to the heart of stimulating atrial receptors in the dog.

    PubMed

    Walters, G E; Mary, D A

    1986-10-01

    In chloralose-anaesthetized dogs, distension of small balloons at the pulmonary vein-atrial junctions to stimulate atrial receptors with myelinated vagal afferent nerves causes an increase in heart rate but does not influence the activity in efferent vagal cardiac nerves. However, distension of these small balloons also stimulates atrial receptors with non-myelinated vagal and sympathetic afferent nerves, which are thought to affect the heart rate and activity in efferent vagal cardiac nerves. In the present investigation, seven dogs anaesthetized with chloralose were studied by distension of small balloons at the pulmonary vein-atrial junctions and in the left atrial appendage, and by graded cooling of the vagal nerves in the neck; cooling to 9 degrees C was used to prevent the increase in activity in myelinated vagal afferent nerves to distension of the small balloons and cooling to 0 degree C was used to prevent responses to the distension in all vagal afferent nerves. Eleven vagal efferent nerve fibers were studied which responded to stimulation of carotid baroreceptors and chemoreceptors. Distension of the small balloons did not affect the activity in these eleven efferent vagal nerve fibres, with the vagi at 37 degrees C or during vagal cooling to 9 degrees C or to 0 degree C. The results indicate that upon distension of the small balloons, none of the three types of atrial receptor influence the activity in efferent vagal cardiac nerves. The results support the conclusion that stimulation of atrial receptors with myelinated vagal afferent nerves, responsible for the reflex increase in heart rate, does not influence the activity in efferent vagal cardiac nerves.

  4. Left Atrial Epicardial Adiposity and Atrial Fibrillation

    PubMed Central

    Batal, Omar; Schoenhagen, Paul; Shao, Mingyuan; Ayyad, Ala Eddin; Van Wagoner, David R.; Halliburton, Sandra S.; Tchou, Patrick J.; Chung, Mina K.

    2010-01-01

    Background Atrial fibrillation (AF) has been linked to inflammatory factors and obesity. Epicardial fat is a source of several inflammatory mediators related to the development of coronary artery disease. We hypothesized that periatrial fat may have a similar role in the development of AF. Methods and Results Left atrium (LA) epicardial fat pad thickness was measured in consecutive cardiac CT angiograms performed for coronary artery disease or AF. Patients were grouped by AF burden: no (n=73), paroxysmal (n=60), or persistent (n=36) AF. In a short-axis view at the mid LA, periatrial epicardial fat thickness was measured at the esophagus (LA-ESO), main pulmonary artery, and thoracic aorta; retrosternal fat was measured in axial view (right coronary ostium level). LA area was determined in the 4-chamber view. LA-ESO fat was thicker in patients with persistent AF versus paroxysmal AF (P=0.011) or no AF (P=0.003). LA area was larger in patients with persistent AF than paroxysmal AF (P=0.004) or without AF (P<0.001). LA-ESO was a significant predictor of AF burden even after adjusting for age, body mass index, and LA area (odds ratio, 5.30; 95% confidence interval, 1.39 to 20.24; P=0.015). A propensity score–adjusted multivariable logistic regression that included age, body mass index, LA area, and comorbidities was also performed and the relationship remained statistically significant (P=0.008). Conclusions Increased posterior LA fat thickness appears to be associated with AF burden independent of age, body mass index, or LA area. Further studies are necessary to examine cause and effect, and if inflammatory, paracrine mediators explain this association. PMID:20504944

  5. The polyuria of paroxysmal atrial tachycardia

    NASA Technical Reports Server (NTRS)

    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.

  6. The dynamics of spin stabilized spacecraft with movable appendages, part 1

    NASA Technical Reports Server (NTRS)

    Bainum, P. M.; Sellappan, R.

    1975-01-01

    The motion and stability of spin stabilized spacecraft with movable external appendages are treated both analytically and numerically. The two basic types of appendages considered are: (1) a telescoping type of varying length and (2) a hinged type of fixed length whose orientation with respect to the main part of the spacecraft can vary. Two classes of telescoping appendages are considered: (a) where an end mass is mounted at the end of an (assumed) massless boom; and (b) where the appendage is assumed to consist of a uniformly distributed homogeneous mass throughout its length. For the telescoping system Eulerian equations of motion are developed. During all deployment sequences it is assumed that the transverse component of angular momentum is much smaller than the component along the major spin axis. Closed form analytical solutions for the time response of the transverse components of angular velocities are obtained when the spacecraft hub has a nearly spherical mass distribution.

  7. Canonical Wnt signalling regulates epithelial patterning by modulating levels of laminins in zebrafish appendages.

    PubMed

    Nagendran, Monica; Arora, Prateek; Gori, Payal; Mulay, Aditya; Ray, Shinjini; Jacob, Tressa; Sonawane, Mahendra

    2015-01-15

    The patterning and morphogenesis of body appendages - such as limbs and fins - is orchestrated by the activities of several developmental pathways. Wnt signalling is essential for the induction of limbs. However, it is unclear whether a canonical Wnt signalling gradient exists and regulates the patterning of epithelium in vertebrate appendages. Using an evolutionarily old appendage - the median fin in zebrafish - as a model, we show that the fin epithelium exhibits graded changes in cellular morphology along the proximo-distal axis. This epithelial pattern is strictly correlated with the gradient of canonical Wnt signalling activity. By combining genetic analyses with cellular imaging, we show that canonical Wnt signalling regulates epithelial cell morphology by modulating the levels of laminins, which are extracellular matrix components. We have unravelled a hitherto unknown mechanism involved in epithelial patterning, which is also conserved in the pectoral fins - evolutionarily recent appendages that are homologous to tetrapod limbs.

  8. Uncontrolled ventricular rate in atrial fibrillation. A manifestation of dissimilar atrial rhythms.

    PubMed Central

    Leier, C V; Johnson, T M; Lewis, R P

    1979-01-01

    A patient with coarse atrial fibrillation and a rapid ventricular response developed periods of high grade atrioventricular block interpersed with periods of rapid ventricular conduction after the administration of digitalis and propranolol. Intracardiac atrial recordings showed similar atrial rhythms of high right atrial flutter and left atrial fibrillation. The low right atrial recordings showed flutter during the periods of fast ventricular rates and fibrillation during periods of slower ventricular rates. Images PMID:475927

  9. Non-Pharmacologic Approach to Prevent Embolization in Patients with Atrial Fibrillation in Whom Anticoagulation is Contraindicated

    PubMed Central

    Sharma, Munish; Khalighi, Koroush

    2017-01-01

    Ischemic stroke is the most common complication of atrial fibrillation (AF). Anticoagulation therapy reduces the risk of systemic embolization in almost all patients with AF irrespective of the type of AF (paroxysmal, persistent or permanent). But, all patients are not suitable candidates for systemic anticoagulation mainly due to the risk of bleeding. Left atrial appendage closure (LAAC) devices have been found to be very effective non-pharmacologic alternative therapy for such patients. There are various types of LAAC devices but United States Food and Drug Administration (US-FDA) have approved only Watchman device. Initially, bigger medical centers in the US had started the insertion of Watchman device but with improving procedural techniques and exciting outcomes, even the community-based hospitals have started to embrace this therapy. We have presented the first three cases of Watchman device placement performed in our hospital and discussed about the indications for placement of LAAC devices. We have also reviewed their efficacy individually. PMID:28243428

  10. Five years of keeping a watch on the left atrial appendage—how has the WATCHMAN fared?

    PubMed Central

    Jazayeri, Mohammad-Ali; Vuddanda, Venkat; Parikh, Valay; Lavu, Madhav; Atkins, Donita; Reddy, Y. Madhu; Nath, Jayant

    2016-01-01

    Left atrial appendage closure (LAAC) is a promising site-directed therapy for stroke prevention in patients with non-valvular atrial fibrillation (AF) who are ineligible or contraindicated for long-term oral anticoagulation. A variety of LAAC modalities are available, including percutaneous endocardial occluder devices such as WATCHMANTM (Boston Scientific Corp., Marlborough, MA, USA), and an ever-increasing body of evidence is helping to define the optimal use of each technique. Similarly increased experience with LAAC has revealed challenges such as device-related thrombi and peri-device leaks for which the long-term significance and appropriate management are areas of active investigation. We review the evolution and long-term outcomes with the WATCHMANTM device with particular emphasis on the nuances of its use and its role in the broader landscape of appendageology. PMID:28149625

  11. The eggshell of the almond wasp Eurytoma amygdali (Hymenoptera, Eurytomidae) - 2. The micropylar appendage.

    PubMed

    Zarani, F E; Margaritis, L H

    1994-08-01

    Micropylar apparatuses in insects are specialized regions of the eggshell through which sperm enters the oocyte. This work is an ultrastructural study and deals with the structure and morphogenesis of the micropylar appendage in the hymenopteran Eurytoma amygdali. The micropylar appendage is a 130 microm long cylindrical protrusion located at the posterior pole of the egg, unlike other insects i.e. Diptera. in which the micropylar apparatus is located at the anterior pole. In mature eggs there is a 0.4 microm wide pore (micropyle) at the tip of the appendage leading to a 6 microm wide micropylar canal. The canal contains an electron-lucent substance, it travels along the whole appendage and finally reaches the vitelline membrane of the oocyte. The vitelline membrane is covered by a wax layer and an electron-lucent layer, whereas the chorion surrounding the canal consists of a granular layer (fine and rough) and a columnar layer. The morphogenesis of the appendage starts in immature follicles: four central cells located at the posterior tip of the oocyte near the vitelline membrane, differing morphologically from the adjacent follicle cells. These central cells degenerate during early chorionic stages, thus assisting in the formation of the micropylar canal. The adjacent, peripherally located cells secrete the electron-lucent substance which fills the canal and at the same time, the fine granular layer is formed starting from the base towards the tip of the appendage. The secretion persists at late chorionic stages and results in the formation of the chorion around the micropylar canal. The extremely long (compared to other insects) micropylar appendage seems to facilitate the egg passage through the very thin and long ovipositor. The structure and morphogenesis of this appendage differs significantly from the micropylar apparatuses studied so far in other insects i.e. Diptera, and may reflect adaptational and evolutionary relationships.

  12. Appendage modal coordinate truncation criteria in hybrid coordinate dynamic analysis. [for spacecraft attitude control

    NASA Technical Reports Server (NTRS)

    Likins, P.; Ohkami, Y.; Wong, C.

    1976-01-01

    The paper examines the validity of the assumption that certain appendage-distributed (modal) coordinates can be truncated from a system model without unacceptable degradation of fidelity in hybrid coordinate dynamic analysis for attitude control of spacecraft with flexible appendages. Alternative truncation criteria are proposed and their interrelationships defined. Particular attention is given to truncation criteria based on eigenvalues, eigenvectors, and controllability and observability. No definitive resolution of the problem is advanced, and exhaustive study is required to obtain ultimate truncation criteria.

  13. [Perioperative management of atrial fibrillation].

    PubMed

    Arguis, M J; Navarro, R; Regueiro, A; Arbelo, E; Sierra, P; Sabaté, S; Galán, J; Ruiz, A; Matute, P; Roux, C; Gomar, C; Rovira, I; Mont, L; Fita, G

    2014-05-01

    Atrial fibrillation is a frequent complication in the perioperative period. When it appears there is an increased risk of perioperative morbidity due to stroke, thromboembolism, cardiac arrest, myocardial infarction, anticoagulation haemorrhage, and hospital readmissions. The current article focuses on the recommendations for the management of perioperative atrial fibrillation based on the latest Clinical Practice Guidelines on atrial fibrillation by the European Society of Cardiology and the Spanish Society of Cardiology. This article pays special attention to the preoperative management, as well as to the acute perioperative episode. For this reason, the latest recommendations for the control of cardiac frequency, antiarrhythmic treatment and anticoagulation are included.

  14. Regulated deployment mechanism for a panel like appendage

    NASA Astrophysics Data System (ADS)

    Bueno, José Ignacio; Vázquez, Javier; Gavira, José Manuel; Migliorero, Gerard

    2001-09-01

    The definition of a cost effective deployment mechanism to deploy 180° panel like appendages in a safe way and with minimum end stroke deployment shock has been a challenge that led the design to achieve a low cost, light, compact, simple, flexible, modular, and low power demanding configuration. This mechanism is composed of an active hinge, that includes an optimised helical torsion spring with a deployment regulator in parallel, and a passive hinge, that includes the end stop and the monitorisation. The main functions of the mechanisms are decoupled in order to make the mechanism as flexible as possible to be adapted to very different needs such as different deployment torque, deployment angle, stiffness, interfaces, monitorisation, etc. The deployment mechanism is provided with a very compact novel deployment regulator based on the progressive melting of a band made of a low melting temperature metal alloy, that is cylindrically disposed. The deployment mechanism has been subject to a qualification test campaign including an extensive characterisation of the deployment regulator.

  15. Photodynamic Therapy and Skin Appendage Disorders: A Review

    PubMed Central

    Megna, Matteo; Fabbrocini, Gabriella; Marasca, Claudio; Monfrecola, Giuseppe

    2017-01-01

    Photodynamic therapy (PDT) is a noninvasive treatment that utilizes light treatment along with application of a photosensitizing agent. In dermatology, PDT is commonly used and approved for the treatment of oncological conditions such as actinic keratosis, Bowen disease and superficial basal cell carcinoma. In the last 2 decades however, PDT has also been used for the treatment of several nonneoplastic dermatological diseases. The present review summarizes published data on PDT application in skin appendage disorders. Our literature review shows that: (a) PDT may be a suitable treatment for acne, folliculitis decalvans, hidradenitis suppurativa, nail diseases, and sebaceous hyperplasia; (b) there is a lack of agreement on PDT features (type, concentrations and incubation period of used substances, number and frequency of PDT sessions, optimal parameters of light sources, and patient characteristics [e.g., failure to previous treatments, disease severity, body surface area involved, etc.] which should guide PDT use in these diseases); (c) further research is needed to establish international guidelines helping dermatologists to choose PDT for the right patient at the right time. PMID:28232927

  16. Regeneration versus scarring in vertebrate appendages and heart.

    PubMed

    Jaźwińska, Anna; Sallin, Pauline

    2016-01-01

    Injuries to complex human organs, such as the limbs and the heart, result in pathological conditions, for which we often lack adequate treatments. While modern regenerative approaches are based on the transplantation of stem cell-derived cells, natural regeneration in lower vertebrates, such as zebrafish and newts, relies predominantly on the intrinsic plasticity of mature tissues. This property involves local activation of the remaining material at the site of injury to promote cell division, cell migration and complete reproduction of the missing structure. It remains an unresolved question why adult mammals are not equally competent to reactivate morphogenetic programmes. Although organ regeneration depends strongly on the proliferative properties of cells in the injured tissue, it is apparent that various organismic factors, such as innervation, vascularization, hormones, metabolism and the immune system, can affect this process. Here, we focus on a correlation between the regenerative capacity and cellular specialization in the context of functional demands, as illustrated by appendages and heart in diverse vertebrates. Elucidation of the differences between homologous regenerative and non-regenerative tissues from various animal models is essential for understanding the applicability of lessons learned from the study of regenerative biology to clinical strategies for the treatment of injured human organs.

  17. [Stroke. are there any difference between patients with or without patent foramen ovale in left atrial appendage systolic function?].

    PubMed

    Contreras, Alejandro E; Perrote, Federico; Concari, Ignacio; Brenna, Eduardo J; Lucero, Cecilia

    2012-01-01

    Introducción: El objetivo del presente trabajo fue comparar la función sistólica de la orejuela de la aurícula izquierda (OAI) en un grupo de pacientes con y sin foramen oval permeable (FOP) quienes sufrieron eventos cerebrovasculares isquémicos. Material y métodos: Entre septiembre de 2010 y octubre de 2011, 17 pacientes fueron enviados para la realización de un ecocardiograma transesofágico (ETE) por haber sufrido un accidente cerebrovascular (ACV). Se definió FOP al pasaje de al menos una burbuja a través del septum interauricular con test de burbujas. Se comparó la velocidad sistólica en la orejuela entre los pacientes con y sin FOP y con un grupo control. Resultados: Fueron 8 mujeres y 9 hombres, con una edad media de 54,1 ± 19,5 años. Todos los pacientes habían sufrido un evento cerebrovascular isquémico, el 41,2% habían tenido ACV, el 52,9% crisis isquémica transitoria y el 5,9% amaurosis fugaz. En la evaluación con ETE, el 11,8% tuvo aneurisma del septum interauricular y el 35,3% FOP. La velocidad sistólica media de la OAI fue 66,3 ± 20,3 cm/seg. No hubo diferencia en la velocidad sistólica de la OAI entre pacientes con o sin FOP (67,5 ± 11,8 cm/seg vs 65,7 ± 24,3 cm/seg respectivamente, p= 0,87). El grupo control compuesto por 8 pacientes, 5 mujeres y 3 hombres, con una edad media de 39,5 ± 18 años, tuvo una velocidad sistólica de la OAI de 77,6 ± 28,9 cm/seg, sin diferencias significativas con los pacientes isquémicos. Conclusión: No hubo diferencias en la función sistólica de la OAI entre pacientes con y sin FOP con eventos cerebrovasculares isquemicos.

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

    PubMed

    Tilman, V

    2014-09-01

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

  19. Atrial Septal Defect (For Kids)

    MedlinePlus

    ... wall called the septum that normally separates the blue and red blood. In a person with an atrial septal defect, there's an opening in that wall. This hole in the wall lets oxygen-rich blood from ...

  20. Atrial fibrillation and anabolic steroids.

    PubMed

    Sullivan, M L; Martinez, C M; Gallagher, E J

    1999-01-01

    A young male bodybuilder, consuming large doses of anabolic steroids (AS), presented to the Emergency Department (ED) with symptomatic rapid atrial fibrillation (AF). Echocardiogram revealed significant septal hypokinesis, and posterior and septal wall thickness at the upper limit of normal for highly trained athletes. The atrial fibrillation had not recurred at 10 weeks after discontinuation of AS use. Consumption of these agents in athletes has been associated with hypertension, ischemic heart disease, hypertrophic cardiomyopathy, and sudden death.

  1. Rhythm control in atrial fibrillation.

    PubMed

    Piccini, Jonathan P; Fauchier, Laurent

    2016-08-20

    Many patients with atrial fibrillation have substantial symptoms despite ventricular rate control and require restoration of sinus rhythm to improve their quality of life. Acute restoration (ie, cardioversion) and maintenance of sinus rhythm in patients with atrial fibrillation are referred to as rhythm control. The decision to pursue rhythm control is based on symptoms, the type of atrial fibrillation (paroxysmal, persistent, or long-standing persistent), patient comorbidities, general health status, and anticoagulation status. Many patients have recurrent atrial fibrillation and require further intervention to maintain long term sinus rhythm. Antiarrhythmic drug therapy is generally recommended as a first-line therapy and drug selection is on the basis of the presence or absence of structural heart disease or heart failure, electrocardiographical variables, renal function, and other comorbidities. In patients who continue to have recurrent atrial fibrillation despite medical therapy, catheter ablation has been shown to substantially reduce recurrent atrial fibrillation, decrease symptoms, and improve quality of life, although recurrence is common despite continued advancement in ablation techniques.

  2. Evolution of nubbin function in hemimetabolous and holometabolous insect appendages

    PubMed Central

    Turchyn, Nataliya; Chesebro, John; Hrycaj, Steven; Couso, Juan P.; Popadić, Aleksandar

    2011-01-01

    Insects display a whole spectrum of morphological diversity, which is especially noticeable in the organization of their appendages. A recent study in a hemipteran, Oncopeltus fasciatus (milkweed bug), showed that nubbin (nub) affects antenna morphogenesis, labial patterning, the length of the femoral segment in legs, and the formation of a limbless abdomen. To further determine the role of this gene in the evolution of insect morphology, we analyzed its functions in two additional hemimetabolous species, Acheta domesticus (house cricket) and Periplaneta americana (cockroach), and re-examined its role in Drosophila. While both Acheta and Periplaneta nub-RNAi first nymphs develop crooked antennae, no visible changes are observed in the morphologies of their mouthparts and abdomen. Instead, the main effect is seen in legs. The joint between the tibia and first tarsomere (Ta-1) is lost in Acheta, which in turn, causes a fusion of these two segments and creates a chimeric nub-RNAi tibia-tarsus that retains a tibial identity in its proximal half and acquires a Ta-1 identity in its distal half. Similarly, our re-analysis of nub function in Drosophila reveals that legs lack all true joints and the fly tibia also exhibits a fused tibia and tarsus. Finally, we observe a similar phenotype in Periplaneta except that it encompasses different joints (coxa-trochanter and femur-tibia), and in this species we also show that nub expression in the legs is regulated by Notch signaling, as had previously been reported in flies and spiders. Overall, we propose that nub acts downstream of Notch on the distal part of insect leg segments to promote their development and growth, which in turn is required for joint formation. Our data represent the first functional evidence defining a role for nub in leg segmentation and highlight the varying degrees of its involvement in this process across insects. PMID:21708143

  3. Evolution of nubbin function in hemimetabolous and holometabolous insect appendages.

    PubMed

    Turchyn, Nataliya; Chesebro, John; Hrycaj, Steven; Couso, Juan P; Popadić, Aleksandar

    2011-09-01

    Insects display a whole spectrum of morphological diversity, which is especially noticeable in the organization of their appendages. A recent study in a hemipteran, Oncopeltus fasciatus (milkweed bug), showed that nubbin (nub) affects antenna morphogenesis, labial patterning, the length of the femoral segment in legs, and the formation of a limbless abdomen. To further determine the role of this gene in the evolution of insect morphology, we analyzed its functions in two additional hemimetabolous species, Acheta domesticus (house cricket) and Periplaneta americana (cockroach), and re-examined its role in Drosophila melanogaster (fruit fly). While both Acheta and Periplaneta nub-RNAi first nymphs develop crooked antennae, no visible changes are observed in the morphologies of their mouthparts and abdomen. Instead, the main effect is seen in legs. The joint between the tibia and first tarsomere (Ta-1) is lost in Acheta, which in turn, causes a fusion of these two segments and creates a chimeric nub-RNAi tibia-tarsus that retains a tibial identity in its proximal half and acquires a Ta-1 identity in its distal half. Similarly, our re-analysis of nub function in Drosophila reveals that legs lack all true joints and the fly tibia also exhibits a fused tibia and tarsus. Finally, we observe a similar phenotype in Periplaneta except that it encompasses different joints (coxa-trochanter and femur-tibia), and in this species we also show that nub expression in the legs is regulated by Notch signaling, as had previously been reported in flies and spiders. Overall, we propose that nub acts downstream of Notch on the distal part of insect leg segments to promote their development and growth, which in turn is required for joint formation. Our data represent the first functional evidence defining a role for nub in leg segmentation and highlight the varying degrees of its involvement in this process across insects.

  4. Acute myocardial infarction caused by left atrial myxoma: Role of intracoronary catheter aspiration.

    PubMed

    Al-Fakhouri, Ahmad; Janjua, Muhammad; DeGregori, Michele

    2017-01-01

    Acute ST-segment elevation myocardial infarction (STEMI) caused by left atrial myxoma is very rare. Catheter-based approaches or thrombolytic therapy are mostly the first step in the management of STEMI with less time delay. We report a case of acute anterior/lateral STEMI caused by a left atrial myxoma. The patient was successfully treated by intracoronary aspiration with an Export aspiration catheter, with excellent distal coronary flow. Intracoronary catheter aspiration in acute myocardial infarction caused by a left atrial myxoma may help to salvage the infarcting myocardium with less time delay.

  5. Limited ability to activate protein C confers left atrial endocardium a thrombogenic phenotype. A role in cardioembolic stroke?

    PubMed Central

    Cerveró, Jorge; Montes, Ramón; España, Francisco; Esmon, Charles T.; Hermida, José

    2011-01-01

    Background and Purpose Atrial fibrillation is the most important risk factor for cardioembolic stroke. Thrombi form in the left atrial appendage rather than in the right. The causes of this different thrombogenicity are not well understood. The goal herein was to compare the activation of the anticoagulant protein C as well as the thrombomodulin and endothelial protein C/activated protein C receptor (EPCR) expression on the endocardium between right and left atria. Methods We harvested the atria of six monkeys (Macaca fascicularis) and quantified their ability to activate protein C ex vivo and we measured the thrombomodulin and EPCR expression by immunofluorescence. Results We found the ability to activate protein C decreased by half (P= 0.028), and there was lower expression of thrombomodulin in the left atrial endocardium than the right (52.5±19.9 and 72.1±18.8 arbitrary intensity units, mean ± standard deviation, P= 0.028). No differences were detected in EPCR expression. Conclusions Impaired protein C activation on the left atrial endocardium, due to low thrombomodulin expression may explain its higher thrombogenicity and play a role in cardioembolic stroke. PMID:21700937

  6. The impact of 6 weeks of atrial fibrillation on left atrial and ventricular structure and function

    PubMed Central

    Kazui, Toshinobu; Henn, Mathew C.; Watanabe, Yoshiyuki; Kovács, Sándor J.; Lawrance, Christopher P.; Greenberg, Jason W.; Moon, Marc; Schuessler, Richard B.; Damiano, Ralph J.

    2015-01-01

    Objective The impact of prolonged episodes of atrial fibrillation on atrial and ventricular function has been incompletely characterized. The purpose of this study was to investigate the influence of atrial fibrillation on left atrial and ventricular function in a rapid paced porcine model of atrial fibrillation. Methods A control group of pigs (group 1, n = 8) underwent left atrial and left ventricular conductance catheter studies and fibrosis analysis. A second group (group 2, n = 8) received a baseline cardiac magnetic resonance imaging to characterize left atrial and left ventricular function. The atria were rapidly paced into atrial fibrillation for 6 weeks followed by cardioversion and cardiac magnetic resonance imaging. Results After 6 weeks of atrial fibrillation, left atrial contractility defined by atrial end-systolic pressure-volume relationship slope was significantly lower in group 2 than in group 1 (1.1 ± 0.5 vs 1.7 ± 1.0; P = .041), whereas compliance from the end-diastolic pressure-volume relationship was unchanged (1.5 ± 0.9 vs 1.6 ± 1.3; P = .733). Compared with baseline, atrial fibrillation resulted in a significantly higher contribution of left atrial reservoir volume to stroke volume (32% vs 17%; P = .005) and lower left atrial booster pump volume contribution to stroke volume (19% vs 28%; P = .029). Atrial fibrillation also significantly increased maximum left atrial volume (206 ± 41 mL vs 90 ± 21 mL; P < .001). Left atrial fibrosis in group 2 was significantly higher than in group 1. Atrial fibrillation decreased left ventricular ejection fraction (29% ± 9% vs 58 ± 8%; P < .001), but left ventricular stroke volume was unchanged. Conclusions In a chronic model of atrial fibrillation, the left atrium demonstrated significant structural remodeling and decreased contractility. These data suggest that early intervention in patients with persistent atrial fibrillation might mitigate against adverse atrial and ventricular structural

  7. Structural changes in the progression of atrial fibrillation: potential role of glycogen and fibrosis as perpetuating factors

    PubMed Central

    Zhang, Ling; Huang, Bing; Scherlag, Benjamin J; Ritchey, Jerry W; Embi, Abraham A; Hu, Jialu; Hou, Yuemei; Po, Sunny S

    2015-01-01

    Background: Previous studies of the goat heart subjected to prolonged atrial pacing induced sustained atrial fibrillation (AF). Structural changes included marked accumulation of glycogen in atrial myocytes. Aims: In the present study, we hypothesized that glycogen deposition in canine atrial myocytes promotes paroxysmal forms of AF and is involved in fibrosis development in the later stages of AF. Material & methods: In dogs under pentobarbital anesthesia, tissues were obtained from the right and left atrial appendages (LAA/RAA). Periodic acid Schiff (PAS) and Masson’s trichrome staining of the LAA/RAA from normal dogs, and those subjected to atrial pacing induced AF for 48 h or 8 weeks determined glycogen and collagen concentrations, respectively, using morphometric analysis. Results: At baseline, there was a significant greater concentration of glycogen in the LAA than the RAA (P ≤ 0.05). Compared to the RAA, the LAA glycogen, was dense and locked against the intercalated discs. After pacing induced AF for 48 hours and 8 weeks there was a marked increase in glycogen deposition, significantly greater than in the baseline state (P ≤ 0.05). There was a similar and progressive increase in collagen concentrations in each group (P ≤ 0.05). Conclusions: The differential in glycogen concentration, in conjunction with other factors, neural and electrophysiological, provide a basis for the greater propensity of the left atrium for paroxysmal AF, at baseline and 48 hours of pacing induced AF. The marked increase in collagen at 8 weeks of pacing provides a substrate for sustained AF. Evidence is presented linking glycogen accumulation and fibrosis as factors in the persistent forms of AF. PMID:25973058

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

    PubMed

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

    2016-10-01

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

  9. Atrial fibrillation in endurance athletes.

    PubMed

    Wilhelm, Matthias

    2014-08-01

    There is a growing population of veteran endurance athletes, regularly participating in training and competition. Although the graded benefit of exercise on cardiovascular health and mortality is well established, recent studies have raised concern that prolonged and strenuous endurance exercise may predispose to atrial and ventricular arrhythmias. Atrial fibrillation (AF) and atrial flutter are facilitated by atrial remodelling, atrial ectopy, and an imbalance of the autonomic nervous system. Endurance sports practice has an impact on all of these factors and may therefore act as a promoter of these arrhythmias. In an animal model, long-term intensive exercise training induced fibrosis in both atria and increased susceptibility to AF. While the prevalence of AF is low in young competitive athletes, it increases substantially in the aging athlete, which is possibly associated with an accumulation of lifetime training hours and participation in competitions. A recent meta-analysis revealed a 5-fold increased risk of AF in middle-aged endurance athletes with a striking male predominance. Beside physical activity, height and absolute left atrial size are independent risk factors for lone AF and the stature of men per se may explain part of their higher risk of AF. Furthermore, for a comparable amount of training volume and performance, male non-elite athletes exhibit a higher blood pressure at rest and peak exercise, a more concentric type of left ventricular remodelling, and an altered diastolic function, possibly contributing to a more pronounced atrial remodelling. The sports cardiologist should be aware of the distinctive features of AF in athletes. Therapeutic recommendations should be given in close cooperation with an electrophysiologist. Reduction of training volume is often not desired and drug therapy not well tolerated. An early ablation strategy may be appropriate for some athletes with an impaired physical performance, especially when continuation of

  10. Segmental mismatch in crustacean appendages: the naupliar antennal exopod of Artemia (Crustacea, Branchiopoda, Anostraca).

    PubMed

    Maruzzo, Diego; Minelli, Alessandro; Fusco, Giuseppe

    2009-03-01

    Based on traditional techniques and confocal laser scanning microscopy for external morphology, and immunohistochemistry for the muscular system, we describe here the segmental features of the antennal exopod of Artemia nauplii. Two kinds of serial elements are present, i.e. setae (with cuticular folds at their base) and ringlets (serially arranged sclerites separated by joint-like cuticular folds not extending to form complete rings around the appendage). The two series are usually not in register. The cuticular folds of the setae and of the ringlets are also sites of intermediate insertions of the three exopod muscles: as the two tegumentary structures are discordant in periodicity, this is also mirrored in the pattern of muscle insertions on the two sides of the appendage. Similar cases of segmental mismatch are known for the trunk of several arthropods, but segmental mismatch along the appendages has received very little attention. The occurrence of segmental mismatch in the naupliar appendages of both extant and fossil crustaceans is reviewed and it is suggested here to be a primitive feature of the exopods of both second antennae and mandibles. Problems in the interpretation of morphological evidence are discussed, also in relation to development and evolution of segmentation of naupliar appendages.

  11. Specialized appendages in fuxianhuiids and the head organization of early euarthropods.

    PubMed

    Yang, Jie; Ortega-Hernández, Javier; Butterfield, Nicholas J; Zhang, Xi-guang

    2013-02-28

    The organization of the head provides critical data for resolving the phylogenetic relationships and evolutionary history of extinct and extant euarthropods. The early Cambrian-period fuxianhuiids are regarded as basal representatives of stem-group Euarthropoda, and their anterior morphology therefore offers key insights for reconstructing the ancestral condition of the euarthropod head. However, the paired post-antennal structures in Fuxianhuia protensa remain controversial; they have been interpreted as both 'great appendages' and as gut diverticulae. Here we describe Chengjiangocaris kunmingensis sp. nov. and Fuxianhuia xiaoshibaensis sp. nov. from a new early Cambrian (Stage 3) fossil Lagerstätte in Yunnan, China. Numerous specimens of both species show a unique 'taphonomic dissection' of the anterodorsal head shield, revealing the cephalic organization in detail. We demonstrate the presence of a pair of specialized post-antennal appendages (SPAs) in the fuxianhuiid head, which attach at either side of the posteriorly directed mouth, behind the hypostome. Preserved functional articulations indicate a well-defined but restricted range of limb movement, suggestive of a simple type of sweep feeding. The organization of the SPAs in fuxianhuiids is incompatible with the (deutocerebral) anterior raptorial appendages of megacheirans, and argue against the presence of protocerebral limbs in the fuxianhuiids. The positions of the fuxianhuiid antennae and SPAs indicate that they are segmentally homologous to the deutocerebral and tritocerebral appendages of crown-group Euarthropoda respectively. These findings indicate that antenniform deutocerebral appendages with many podomeres are a plesiomorphic feature of the ancestral euarthropod head.

  12. Input-Shaped Link Motion Control of Planar Space Robot Equipped with Flexible Appendage

    NASA Astrophysics Data System (ADS)

    Kasai, Shinya; Kojima, Hirohisa

    Control of a space robot without actuators on the main body is an underactuated control problem. Various stabilization methods, such as the time-varying feedback control method, discontinuous feedback control method, center manifold-based method, zero-dynamics method and sliding-mode control method have been proposed. However, past studies have not considered underactuated space robots equipped with a flexible appendage, such as solar panels. If the manipulators are simply controlled to achieve the target state for the robot using the past controllers without taking a flexible appendage into consideration, residual vibration remains even after the link motion has finished. In order to suppress the residual vibration on the flexible appendage, we apply the input-shaping technique to the link motion of an underactuated planar space robot. Numerical and experimental studies are carried out to validate the proposed method for a planar dual-link space robot with a flexible appendage. The results show that the proposed method is capable of not only controlling the link angles and the main body attitude to the goal angles, but also suppressing the residual vibration on the flexible appendage.

  13. Atrial Myxoma: A Case Presentation and Review

    PubMed Central

    Cohen, Ronny; Singh, Gagandeep; Mena, Derrick; Garcia, Christine A.; Loarte, Pablo; Mirrer, Brooks

    2012-01-01

    Myxomas are the most common primary cardiac tumors, most frequently found in the left atrium. We present a case of an atrial myxoma. An in-depth review of atrial myxoma is presented, examining the important clinical symptoms and diagnostic indicators. The treatment of atrial myxoma is then discussed, with an emphasis on current therapies. An extensive literature review has been performed to present a comprehensive review of the causes, pathophysiology of atrial myxoma.

  14. Post-Acceleration Chaotic Atrial Rhythm

    DTIC Science & Technology

    1982-04-01

    atrial flutter or two discrete P-wave morphologies with the rate less fibrillation. than 100 bpm). and sinus bradycardia. An occasional The time...mulhilocal paroxysmal atrial tach.- cardia with cclic Wcnckchach phenomenon under observation examinations. The chaotic atrial rhythm in this case ji r 13...CHAOTIC ATRIAL RHYTHM Final Report 1 July 81 - 30 July 81 6. PERFORMING OIG. REPORT NUMBER 7. AUTHOR(s) 8 CONTRACT OR GRANT NUMBERS) r James E

  15. Acetylcholine-Atropine Interactions: Paradoxical Effects on Atrial Fibrillation Inducibility.

    PubMed

    Liu, Yu; Scherlag, Benjamin J; Fan, Youqi; Xia, Wenfang; Huang, He; Po, Sunny S

    2017-03-21

    Atropine (ATr) is well known as a cholinergic antagonist, however, at low concentrations ATr could paradoxically accentuate the parasympathetic actions of acetylcholine (ACh). In 22 pentobarbital anesthetized dogs, via a left and right thoracotomy, a leak proof barrier was attached to isolate the atrial appendages (AAs) from the rest of the atria. In Group 1(Ach+ATr+Ach), ACh, 100 mM, was placed on the AA followed by the application of ATr, 2mg/cc. The average AFdur was 17±7 minutes. After ATr was applied to the AA and ACh again tested, the AFdur was markedly attenuated (2±2 minutes, p<0.05). In Group 2 (ATr+Ach), ATr was initially applied to the AA followed by the application of ACh, 100 mM. There was no significant difference in AF duration (16±4 minutes vs 18±2 minutes, p=NS). The inhibitory effect of ATr on induced HR reduction (electrical stimulation of the anterior right ganglionated plexi and vagal nerves) was no difference between Groups 1 and 2. These observations suggest that when ATr is initially administered it attaches to the allosteric site of the muscarinic ACh receptor (M2 AChRs) leaving the orthosteric site free to be occupied by ACh. The M3 receptor that controls HR slowing does not show the same allosteric properties.

  16. Silent Atrial Fibrillation and Cryptogenic Strokes.

    PubMed

    Dalen, James E; Alpert, Joseph S

    2017-03-01

    A new suspected cause of cryptic strokes is "silent atrial fibrillation." Pacemakers and other implanted devices allow continuous recording of cardiac rhythm for months or years. They have discovered that short periods of atrial fibrillation lasting minutes or hours are frequent and usually are asymptomatic. A meta-analysis of 50 studies involving more than 10,000 patients with a recent stroke found that 7.7% had new atrial fibrillation on their admitting electrocardiogram. In 3 weeks during and after hospitalization, another 16.9% were diagnosed. A total of 23.7% of these stroke patients had silent atrial fibrillation; that is, atrial fibrillation diagnosed after hospital admission. Silent atrial fibrillation is also frequent in patients with pacemakers who do not have a recent stroke. In a pooled analysis of 3 studies involving more than 10,000 patients monitored for 24 months, 43% had at least 1 day with atrial fibrillation lasting more than 5 minutes. Ten percent had atrial fibrillation lasting at least 12 hours. Despite the frequency of silent atrial fibrillation in these patients with multiple risk factors for stroke, the annual incidence of stroke was only 0.23%. When silent atrial fibrillation is detected in patients with recent cryptogenic stroke, anticoagulation is indicated. In patients without stroke, silent atrial fibrillation should lead to further monitoring for clinical atrial fibrillation rather than immediate anticoagulation, as some have advocated.

  17. Ultrastructural observations on feeding appendages and gills of Alvinella pompejana (Annelida, Polychaeta)

    NASA Astrophysics Data System (ADS)

    Storch, V.; Gaill, F.

    1986-09-01

    The feeding appendages of Alvinella pompejana obtained from a deep-sea hydrothermal vent environment are described. They are characterized by a ciliated groove, the cells of which have a very distinctive ultrastructure, by groups of bipolar receptor cells and by several kinds of gland cells. Among these, one cell type is in an upside down position suggesting a function completely different from other epidermal secretory cells. The gills differ considerably from the feeding appendages on the basis of their ultrastructure. Their epidermis is very irregular in height; basal infoldings give the blood access to a space coming very near to the external medium. The blood vascular system is open. On the other hand, the gills of Amphicteis gunneri are not effective sites of gas exchange, since their columnar epithelium is underlain with muscle cells. The cells composing the feeding appendages and gills of Alvinella pompejana are characterized by ultrastructurally very different mitochondria.

  18. Skin appendage-derived stem cells: cell biology and potential for wound repair.

    PubMed

    Xie, Jiangfan; Yao, Bin; Han, Yutong; Huang, Sha; Fu, Xiaobing

    2016-01-01

    Stem cells residing in the epidermis and skin appendages are imperative for skin homeostasis and regeneration. These stem cells also participate in the repair of the epidermis after injuries, inducing restoration of tissue integrity and function of damaged tissue. Unlike epidermis-derived stem cells, comprehensive knowledge about skin appendage-derived stem cells remains limited. In this review, we summarize the current knowledge of skin appendage-derived stem cells, including their fundamental characteristics, their preferentially expressed biomarkers, and their potential contribution involved in wound repair. Finally, we will also discuss current strategies, future applications, and limitations of these stem cells, attempting to provide some perspectives on optimizing the available therapy in cutaneous repair and regeneration.

  19. Epicardial Atrial Ablation Using a Novel Articulated Robotic Medical Probe Via a Percutaneous Subxiphoid Approach.

    PubMed

    Ota, Takeyoshi; Degani, Amir; Zubiate, Brett; Wolf, Alon; Choset, Howie; Schwartzman, David; Zenati, Marco A

    2006-01-01

    OBJECTIVE: Minimally invasive epicardial atrial ablation to cure atrial fibrillation through the use of a percutaneous subxiphoid approach currently has a lack of dedicated technology for intrapericardial navigation around the beating heart. We have developed a novel articulated robotic medical probe and performed preliminary experiments in a porcine preparation. METHODS: In five large, healthy pigs, the teleoperated robotic system was introduced inside the pericardial space through a percutaneous subxiphoid approach. Secondary visualization of the left atrium and left atrial appendage was achieved with the use of a 5-mm scope inserted through a left thoracic port. The operator actively controlled the path of the robot by using a master manipulator. The catheter, with an irrigated radiofrequency tip, was guided through the working port of the robot to achieve epicardial ablation of the left atrium. RESULTS: Access to the pericardial space and progression around the left atrium was successful in all cases, with no interference with the beating heart such as a fatal arrhythmia, unexpected bleeding, and hypotension. Epicardial ablation was successfully performed in all five cases. No adverse hemodynamic or electrophysiological events were noted during the trials. When the animals were killed, there was no visually detected injury on the surrounding mediastinal structures caused by ablation. Transmural ablation was confirmed by histopathology of the left atrium. CONCLUSIONS: We have developed a dedicated articulated robotic medical probe and successfully performed epicardial left atrial radiofrequency ablation. Based on the feedback from these preliminary experiments, the radius of curvature and proper visualization of the device are being improved in the next generation prototype.

  20. Nonlinear analysis of the ECG during atrial fibrillation in patients for low energy internal cardioversion.

    PubMed

    Diaz, J; Gonzalez, C; Escalona, O; Glover, B M; Manoharan, G

    2008-01-01

    The goal of this study was to investigate the usefulness of nonlinear analysis in determining the success of low energy internal cardioversion (IC) in patients with atrial fibrillation (AF). Nonlinear analysis has previously been used for characterizing AF patterns, and spontaneous termination in its paroxysmal form. However, the relationship between the probability to restore sinus rhythm by IC and quantitative nonlinear analysis based electrocardiographic (ECG) markers has not been explored before. Thirty nine patients with AF, for elective DC cardioversion at the Royal Victoria Hospital in Belfast, were included in this study. One catheter was positioned in the right atrial appendage and another in the coronary sinus, to deliver a biphasic shock waveform. A voltage step-up protocol (50-300 V) was used for patient cardioversion. Residual atrial fibrillatory signal (RAFS) was derived from 60 seconds of surface ECG from defibrillator pads, prior to shock delivery, by bandpass filtering and ventricular activity (QRST) cancellation. QRST complexes were cancelled using a recursive least squared (RLS) adaptive filter. The maximal Lyapunov exponent (lambda), correlation dimension (course grained estimation, CDcg) and approximate entropy (ApEn) were extracted from the RAFS. These variables were calculated from 10 s of the RAFS before shock delivery. 26 patients were successfully cardioverted, employing a maximum energy of 11.84 joules. A lower lambda (0.037+/-0.006 vs. 0.044+/-0.008, P=0.01) and CDcg (5.552+/-2.075 vs. 6.592+/-1.130, P=0.049) were found in successfully cardioverted patients than in those non successful ones, with an energy atrial fibrillation.

  1. Atrial expression of the CCN1 and CCN2 proteins in chronic heart failure.

    PubMed

    Bonda, Tomasz A; Kamiński, Karol A; Dziemidowicz, Magdalena; Litvinovich, Sergey; Kożuch, Marcin; Hirnle, Tomasz; Dmitruk, Iwona; Chyczewski, Lech; Winnicka, Maria M

    2012-04-24

    Previous studies have reported the upregulation of CCN proteins early after acute heart injury. The aim of the present work was to evaluate the expression of the CCN1 and CCN2 proteins and their regulation by angiotensin II in the atrial myocardium of a chronically failing heart. Male adult mice were subjected to ligation of the left coronary artery to produce myocardial infarction (the MI group), and 16 of them were treated for 12 weeks with the AT1 receptor antagonist telmisartan (the MI-Tel group). Sham-operated mice served as controls. The expression of proteins was evaluated by immunohistochemistry 12 weeks after the operation. In shamoperated mice, stainings for CCN1 and CCN2 proteins were positive within atrial cardiomyocytes. CCN1-positive reaction revealed diffused cytoplasmic localization, while CCN2 was present mainly within the perinuclear cytoplasm. CCN1 was upregulated in the MI group, while CCN2 remained at basal level. Telmisartan prevented the upregulation of CCN1 and decreased CCN2 level. We compared the experimental data with the expression of CCN1 and CCN2 proteins in human right atrial appendages. We found an inverse, but not significant, relation between the level of either protein and the left ventricular ejection fraction. This suggests a similar atrial regulation of CCN1 and CCN2 expression also in humans. We conclude that in the murine atria, CCN1 and CCN2 proteins are expressed constitutively. In chronic heart failure, CCN proteins tend to be upregulated, which may be related to the action of angiotensin II.

  2. The chelifores of sea spiders (Arthropoda, Pycnogonida) are the appendages of the deutocerebral segment.

    PubMed

    Brenneis, Georg; Ungerer, Petra; Scholtz, Gerhard

    2008-01-01

    Within the last decade, gene expression patterns and neuro-anatomical data have led to a new consensus concerning the long-debated association between anterior limbs and neuromeres in the arthropod head. According to this new view, the first appendage in all extant euarthropods is innervated by the second neuromere, the deutocerebrum, whereas the anterior-most head region bearing the protocerebrum lacks an appendage. This stands in contrast to the clearly protocerebrally targeted "antennae" of Onychophora and to some evidence for protocerebral limbs in fossil euarthropod representatives. Yet, the latter "frontal appendages" or "primary antennae" have most likely been reduced or lost in the lineage, leading to extant taxa. Surprisingly, a recent neuro-anatomical study on a pycnogonid challenged this evolutionary scenario, reporting a protocerebral innervation of the first appendages, the chelifores. However, this interpretation was soon after questioned by Hox gene expression data. To re-evaluate the unresolved controversy, we analyzed neuro-anatomy and neurogenesis in four pycnogonid species using immunohistochemical techniques. We clearly show the postprotocerebral innervation of the chelifores, which is resolved as the plesiomorphic condition in pycnogonids when evaluated against a recently published comprehensive phylogeny. By providing direct morphological support for the deutocerebral status of the cheliforal ganglia, we reconcile morphological and gene expression data and argue for a corresponding position between the anterior-most appendages in all extant euarthropods. Consequently, other structures have to be scrutinized to illuminate the fate of a presumptive protocerebral appendage in recent euarthropods. The labrum and the "frontal filaments" of some crustaceans are possible candidates for this approach.

  3. Ability of magnetocardiography to detect regional dominant frequencies of atrial fibrillation

    PubMed Central

    Yoshida, Kentaro; Ogata, Kuniomi; Inaba, Takeshi; Nakazawa, Yoko; Ito, Yoko; Yamaguchi, Iwao; Kandori, Akihiko; Aonuma, Kazutaka

    2015-01-01

    Background Lead V1 on electrocardiography (ECG) can detect the dominant frequency (DF) of atrial fibrillation (AF) in the right atrium (RA). Paroxysmal AF is characterized by a frequency gradient from the left atrium (LA) to the right atrium (RA). We examined the ability of magnetocardiography (MCG) to detect regional DFs in both the atria. Methods Study subjects comprised 18 consecutive patients referred for catheter ablation of persistent AF. An MCG system with 64 magnetic sensors was used to perform MCG in the frontal, lateral, and back planes prior to the ablation procedure in each patient. DFMCG and organization index (OIMCG) were calculated using fast Fourier transformation. Intracardiac electrograms (ICEs) in both the atria and the coronary sinus (CS) were mapped at 17 sites. Regional DFsICE were also determined. Results Mean LA DFICE was higher than mean RA DFICE (6.40±0.66 versus 6.16±0.80 Hz, P=0.03). DFMCG in the channel having the highest OIMCG was 6.61±0.88 Hz in the frontal plane, 6.52±0.64 Hz in the lateral plane, and 6.42±0.62 Hz in the back plane (P=0.3). In each plane, DFMCG correlated with DFICE at the RA appendage (R=0.95, P<0.0001), the LA appendage (R=0.91, P<0.0001), and the CS (R=0.93, P<0.0001). DFECG in V5 modestly correlated with DFICE at the LA appendage (R=0.82, P<0.0001). Conclusions MCG could more precisely detect the DFs in the LA and the CS than ECG. However, the usefulness of pre-procedural detection of the AF frequency gradient for ablation therapy needs to be evaluated in future prospective studies. PMID:26702313

  4. Dual-enhancement cardiac computed tomography for assessing left atrial thrombus and pulmonary veins before radiofrequency catheter ablation for atrial fibrillation.

    PubMed

    Hur, Jin; Pak, Hui-Nam; Kim, Young Jin; Lee, Hye-Jeong; Chang, Hyuk-Jae; Hong, Yoo Jin; Choi, Byoung Wook

    2013-07-15

    Noninvasive imaging that provides anatomic information while excluding intracardiac thrombus would be of significant clinical value for patients referred for catheter ablation of atrial fibrillation (AF). This study assessed the diagnostic performance of a dual-enhancement single-phase cardiac computed tomography (CT) protocol for thrombus and circulatory stasis detection in AF patients before catheter ablation. We studied 101 consecutive symptomatic AF patients (71 men and 30 women; mean age, 61.8 years) who were scheduled to have catheter ablation. All patients had undergone pre-AF ablation CT imaging and transesophageal echocardiography on the same day. CT was performed with prospective electrocardiographic gating, and scanning began 180 seconds after the test bolus. Mean left atrial appendage (LAA)/ascending aorta Hounsfield unit (HU) ratios were measured on CT images. Among the 101 patients, 9 thrombi and 18 spontaneous echo contrasts were detected by transesophageal echocardiography. The overall sensitivity, specificity, positive predictive value, and negative predictive value of CT for the detection of thrombi in the LAA were 89%, 100%, 100%, and 99%, respectively. The mean LAA/ascending aorta HU ratios were significantly different between thrombus and circulatory stasis (0.17 vs 0.33, p = 0.002). Dual-enhancement single-scan cardiac CT is a sensitive modality for detecting and differentiating LAA thrombus and circulatory stasis.

  5. Fluid-Structure Interaction Effects Resulting from Hull Appendage Coupling

    DTIC Science & Technology

    2005-09-01

    actual maximum radius which is ultimately reached. Furthermore, after the generation of the maximum bubble radius, the hydrostatic pressure reverses the...radial flow, i.e., causes the outward water flow to stop and then flow reversely . Therefore, the radius of the gas bubble gets smaller, i.e., the...F $ PCHCDS NASTAM STOMAS STOINV F F F T $ FRWTFL FRWTGE FRWTGR FRESUR F T F F

  6. The left atrial "Medusa myxoma".

    PubMed

    Williams, Elbert E; Pratt, Jerry W; Martin, David E

    2014-02-01

    Although myxomas are the most commonly seen primary cardiac tumors, encompassing 30% to 50% of all primary tumors of the heart, they remain a rare finding with an annual reported incidence of 0.5 per million. The presenting symptoms of an atrial myxoma are widely varied as are the clinical consequences. Regardless of presentation, once a diagnosis is made prompt surgical excision is recommended to minimize the potential complications of obstruction or embolization. We present the "Medusa myxoma," an arborizing 4-fingered left atrial myxoma extending from the fossa ovalis across the left atrium.

  7. [Panic disorder and atrial fibrillation].

    PubMed

    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.

  8. Role of the AP2 β-Appendage Hub in Recruiting Partners for Clathrin-Coated Vesicle Assembly

    PubMed Central

    Burtey, Anne; Praefcke, Gerrit J. K; Peak-Chew, Sew-Yeu; Mills, Ian G; Benmerah, Alexandre; McMahon, Harvey T

    2006-01-01

    Adaptor protein complex 2 α and β-appendage domains act as hubs for the assembly of accessory protein networks involved in clathrin-coated vesicle formation. We identify a large repertoire of β-appendage interactors by mass spectrometry. These interact with two distinct ligand interaction sites on the β-appendage (the “top” and “side” sites) that bind motifs distinct from those previously identified on the α-appendage. We solved the structure of the β-appendage with a peptide from the accessory protein Eps15 bound to the side site and with a peptide from the accessory cargo adaptor β-arrestin bound to the top site. We show that accessory proteins can bind simultaneously to multiple appendages, allowing these to cooperate in enhancing ligand avidities that appear to be irreversible in vitro. We now propose that clathrin, which interacts with the β-appendage, achieves ligand displacement in vivo by self-polymerisation as the coated pit matures. This changes the interaction environment from liquid-phase, affinity-driven interactions, to interactions driven by solid-phase stability (“matricity”). Accessory proteins that interact solely with the appendages are thereby displaced to areas of the coated pit where clathrin has not yet polymerised. However, proteins such as β-arrestin (non-visual arrestin) and autosomal recessive hypercholesterolemia protein, which have direct clathrin interactions, will remain in the coated pits with their interacting receptors. PMID:16903783

  9. Laser Atrial Septostomy: An Engineering Problem

    NASA Astrophysics Data System (ADS)

    Ben-Shachar, Giora; Cohen, Mark H.; Riemenschneider, Thomas A.; Beder, Stanley D.

    1987-04-01

    The purpose of this study was to develop a reproducible method for atrial septostomy in live animals, which would be independent of both atrial septal thickness and left atrial size. Seven mongrel dogs monitored electrocardiographically were anesthetized and instrumented with systemic and pulmonary arterial lines. A modified Mullin's transseptal sheath was advanced under fluoroscopic control to interrogate the left atrium and atrial septum. A 400 micron regular quartz or a laser heated metallic tip fiber was passed through the sheath up to the atrial septum. Lasing of the atrial septum was done with an Argon laser at power output of 5 watts. In three dogs, an atrial septosomy catheter was passed to the left atrium through the laser atrial septostomy and balloon atrial septostomy was performed. The laser atrial septostomy measured 3 x 5 mm in diameter. This interatrial communication could be enlarged with a balloon septostomy to over one cm in diameter. Hemodynamic and electrocardiographic monitoring were stable during the procedure. Engineering problems included: 1) radioluscency of the laser fibers thus preventing fluoroscopic localization of the fiber course; and 2) the inability to increase lateral vaporization of the atrial septum. It is concluded that further changes in the lasing fibers need to be made before the method can be considered for clinical use.

  10. Biatrial reduction plasty with reef imbricate technique as an adjunct to maze procedure for permanent atrial fibrillation associated with giant left atria.

    PubMed

    Wang, William; Guo, L Ray; Martland, Anne Marie; Feng, Xiao-Dong; Ma, Jie; Feng, Xi Qing

    2010-04-01

    Success of the modified maze procedure after valvular operation with giant atria and permanent atrial fibrillation (AF) remains suboptimal. We report an aggressive approach for these patients utilizing biatrial reduction plasty with a reef imbricate suture technique concomitantly with valvular and maze procedure for AF. From January 1999 to December 2006, 122 consecutive Chinese patients with permanent AF and biatrial enlargement who required mitral valve+/-tricuspid valve (TV) surgery underwent aggressive left atrial reduction combined with radiofrequency bipolar full maze procedure. Left atrial dimensions were measured by TTE or TEE. There were 71 women (58.1%) and 51 men (41.9%) and their mean age was 45+/-9.5 years. Mean duration of AF was 48.4+/-21.4 months. All patients underwent left atrial reduction plasty with reef imbricate suture technique and full maze procedure. Their preoperative left atria measured 64+/-12 mm in the enlarged left atria (ELA) group and 86+/-17 mm in the giant left atria (GLA). Mitral valve replacement (MVR) combined with TV repair was performed in 102 patients (83%) while 21 patients underwent MVRs combined with aortic valve replacements (17%). Sixty-six (54%) patients required additional procedures and 61 (50%) of the patients also underwent left atrial appendage clot evacuation. Postoperative left atrial size was reduced to 49+/-8 mm (ELA) and 51+/-11 mm (GLA), respectively (P<0.05). Ninety-three of 122 (76%) patients were restored in normal sinus rhythm after one year clinical follow-up. Aggressive biatrial reduction plasty combined with full maze procedure is an effective treatment for patients with permanent AF undergoing concomitant valvular surgery. Further studies utilizing the reef imbricate suture technique for atrial reduction need to subsequently be evaluated.

  11. Origin of archosaurian integumentary appendages: the bristles of the wild turkey beard express feather-type beta keratins.

    PubMed

    Sawyer, Roger H; Washington, Lynette D; Salvatore, Brian A; Glenn, Travis C; Knapp, Loren W

    2003-06-15

    The discovery that structurally unique "filamentous integumentary appendages" are associated with several different non-avian dinosaurs continues to stimulate the development of models to explain the evolutionary origin of feathers. Taking the phylogenetic relationships of the non-avian dinosaurs into consideration, some models propose that the "filamentous integumentary appendages" represent intermediate stages in the sequential evolution of feathers. Here we present observations on a unique integumentary structure, the bristle of the wild turkey beard, and suggest that this non-feather appendage provides another explanation for some of the "filamentous integumentary appendages." Unlike feathers, beard bristles grow continuously from finger-like outgrows of the integument lacking follicles. We find that these beard bristles, which show simple branching, are hollow, distally, and express the feather-type beta keratins. The significance of these observations to explanations for the evolution of archosaurian integumentary appendages is discussed.

  12. Facts about Atrial Septal Defect

    MedlinePlus

    ... Developmental Disabilities) be credited and notified in any public or private usage of this image. Close × Atrial Septal Defect The images are ... Developmental Disabilities) be credited and notified in any public or private usage of this image. Close Information For... ... Makers Language: English ...

  13. Epibulbar lipodermoids, preauricular appendages and polythelia in four generations: a new hereditary syndrome?

    PubMed

    Goldschmidt, Ernst; Jacobsen, Nina

    2010-06-01

    A new syndrome with abnormalities along the first branchial arch and the milk list is described in a family of four affected generations. The characteristics of the syndrome are epibulbar lipodermoids, preauricular appendages and polythelia. The expressivity varies but all affected have supernumerary nipples and preauricular manifestations while visible epibulbar lipodermoids do not seem obligatory. The syndrome has a typical dominant pattern of heredity.

  14. Knockdown of Parhyale Ultrabithorax recapitulates evolutionary changes in crustacean appendage morphology.

    PubMed

    Liubicich, Danielle M; Serano, Julia M; Pavlopoulos, Anastasios; Kontarakis, Zacharias; Protas, Meredith E; Kwan, Elaine; Chatterjee, Sandip; Tran, Khoa D; Averof, Michalis; Patel, Nipam H

    2009-08-18

    Crustaceans possess remarkably diverse appendages, both between segments of a single individual as well as between species. Previous studies in a wide range of crustaceans have demonstrated a correlation between the anterior expression boundary of the homeotic (Hox) gene Ultrabithorax (Ubx) and the location and number of specialized thoracic feeding appendages, called maxillipeds. Given that Hox genes regulate regional identity in organisms as diverse as mice and flies, these observations in crustaceans led to the hypothesis that Ubx expression regulates the number of maxillipeds and that evolutionary changes in Ubx expression have generated various aspects of crustacean appendage diversity. Specifically, evolutionary changes in the expression boundary of Ubx have resulted in crustacean species with either 0, 1, 2, or 3 pairs of thoracic maxillipeds. Here we test this hypothesis by altering the expression of Ubx in Parhyale hawaiensis, a crustacean that normally possesses a single pair of maxillipeds. By reducing Ubx expression, we can generate Parhyale with additional maxillipeds in a pattern reminiscent of that seen in other crustacean species, and these morphological alterations are maintained as the animals molt and mature. These results provide critical evidence supporting the proposition that changes in Ubx expression have played a role in generating crustacean appendage diversity and lend general insights into the mechanisms of morphological evolution.

  15. Morphological and histological organization of the pyriform appendage of the tetrabranchiate Nautilus pompilius (Cephalopoda, Mollusca).

    PubMed

    Spintzik, Jessica; Springer, Jochen; Westermann, Bettina

    2009-04-01

    The pyriform appendage, an organ only found in nautiloid cephalopods was investigated with histological, histochemical and ultrastructural methods in order to characterize the anatomical and the cytological structure of this organ. The pyriform appendage is situated within the genital septum and lies in close contact with the ventricle of the heart. The proximal side ends blindly near the gonad whereas the distal side is developed into a duct. The duct was observed to open into the mantle cavity in juvenile and adult Nautilus pompilius of both sexes. Injections of India ink in the heart demonstrate that the organ is supplied with hemolymph from an artery that extends from the heart. The pyriform appendage is a hollow organ consisting mainly of glandular tissue. The lumen is covered with a columnar epithelium, the tunica mucosa, consisting of only one cell type containing vacuoles with different inclusions. Underneath the tunica mucosa is the tunica muscularis, which is embedded in connective tissue and folded, enlarging the internal surface. A cuboidal tunica serosa surrounds this organ. The vacuoles and the secretory products contain neutral mucopolysaccharides, glycoproteins and glycolipids. Acid phosphatase and serotonin were localized in the tunica mucosa. Acetylcholinesterase, catecholamines and the tetrapeptide FMRF-amide were demonstrated within the nerve endings of the tunica muscularis indicating a dual "cholinergic-aminergic" neuroregulation, possibly modulated by FMRF-amide. These findings suggest that the pyriform appendage is not a rudimentary organ but instead has distinct biological functions in nautiloid cephalopods, possibly in intraspecific communication.

  16. [Atrial fibrillation and cognitive function].

    PubMed

    Duron, Emmanuelle; Hanon, Olivier

    2010-09-01

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

  17. The function of appendage patterning genes in mandible development of the sexually dimorphic stag beetle.

    PubMed

    Gotoh, Hiroki; Zinna, Robert A; Ishikawa, Yuki; Miyakawa, Hitoshi; Ishikawa, Asano; Sugime, Yasuhiro; Emlen, Douglas J; Lavine, Laura C; Miura, Toru

    2017-02-01

    One of the defining features of the evolutionary success of insects is the morphological diversification of their appendages, especially mouthparts. Although most insects share a common mouthpart ground plan, there is remarkable diversity in the relative size and shapes of these appendages among different insect lineages. One of the most prominent examples of mouthpart modification can be found in the enlargement of mandibles in stag beetles (Coleoptera, Insecta). In order to understand the proximate mechanisms of mouthpart modification, we investigated the function of appendage-patterning genes in mandibular enlargement during extreme growth of the sexually dimorphic mandibles of the stag beetle Cyclommatus metallifer. Based on knowledge from Drosophila and Tribolium studies, we focused on seven appendage patterning genes (Distal-less (Dll), aristaless (al), dachshund (dac), homothorax (hth), Epidermal growth factor receptor (Egfr), escargot (esg), and Keren (Krn). In order to characterize the developmental function of these genes, we performed functional analyses by using RNA interference (RNAi). Importantly, we found that RNAi knockdown of dac resulted in a significant mandible size reduction in males but not in female mandibles. In addition to reducing the size of mandibles, dac knockdown also resulted in a loss of the serrate teeth structures on the mandibles of males and females. We found that al and hth play a significant role during morphogenesis of the large male-specific inner mandibular tooth. On the other hand, knockdown of the distal selector gene Dll did not affect mandible development, supporting the hypothesis that mandibles likely do not contain the distal-most region of the ancestral appendage and therefore co-option of Dll expression is unlikely to be involved in mandible enlargement in stag beetles. In addition to mandible development, we explored possible roles of these genes in controlling the divergent antennal morphology of Coleoptera.

  18. Zebrafish foxc1a drives appendage-specific neural circuit development

    PubMed Central

    Banerjee, Santanu; Hayer, Katharina; Hogenesch, John B.; Granato, Michael

    2015-01-01

    Neural connectivity between the spinal cord and paired appendages is key to the superior locomotion of tetrapods and aquatic vertebrates. In contrast to nerves that innervate axial muscles, those innervating appendages converge at a specialized structure, the plexus, where they topographically reorganize before navigating towards their muscle targets. Despite its importance for providing appendage mobility, the genetic program that drives nerve convergence at the plexus, as well as the functional role of this convergence, are not well understood. Here, we show that in zebrafish the transcription factor foxc1a is dispensable for trunk motor nerve guidance but is required to guide spinal nerves innervating the pectoral fins, equivalent to the tetrapod forelimbs. In foxc1a null mutants, instead of converging with other nerves at the plexus, pectoral fin nerves frequently bypass the plexus. We demonstrate that foxc1a expression in muscle cells delineating the nerve path between the spinal cord and the plexus region restores convergence at the plexus. By labeling individual fin nerves, we show that mutant nerves bypassing the plexus enter the fin at ectopic positions, yet innervate their designated target areas, suggesting that motor axons can select their appropriate fin target area independently of their migration through the plexus. Although foxc1a mutants display topographically correct fin innervation, mutant fin muscles exhibit a reduction in the levels of pre- and postsynaptic structures, concomitant with reduced pectoral fin function. Combined, our results reveal foxc1a as a key player in the development of connectivity between the spinal cord and paired appendages, which is crucial for appendage mobility. PMID:25670796

  19. The AP-2 adaptor beta2 appendage scaffolds alternate cargo endocytosis.

    PubMed

    Keyel, Peter A; Thieman, James R; Roth, Robyn; Erkan, Elif; Everett, Eric T; Watkins, Simon C; Heuser, John E; Traub, Linton M

    2008-12-01

    The independently folded appendages of the large alpha and beta2 subunits of the endocytic adaptor protein (AP)-2 complex coordinate proper assembly and operation of endocytic components during clathrin-mediated endocytosis. The beta2 subunit appendage contains a common binding site for beta-arrestin or the autosomal recessive hypercholesterolemia (ARH) protein. To determine the importance of this interaction surface in living cells, we used small interfering RNA-based gene silencing. The effect of extinguishing beta2 subunit expression on the internalization of transferrin is considerably weaker than an AP-2 alpha subunit knockdown. We show the mild sorting defect is due to fortuitous substitution of the beta2 chain with the closely related endogenous beta1 subunit of the AP-1 adaptor complex. Simultaneous silencing of both beta1 and beta2 subunit transcripts recapitulates the strong alpha subunit RNA interference (RNAi) phenotype and results in loss of ARH from endocytic clathrin coats. An RNAi-insensitive beta2-yellow fluorescent protein (YFP) expressed in the beta1 + beta2-silenced background restores cellular AP-2 levels, robust transferrin internalization, and ARH colocalization with cell surface clathrin. The importance of the beta appendage platform subdomain over clathrin for precise deposition of ARH at clathrin assembly zones is revealed by a beta2-YFP with a disrupted ARH binding interface, which does not restore ARH colocalization with clathrin. We also show a beta-arrestin 1 mutant, which engages coated structures in the absence of any G protein-coupled receptor stimulation, colocalizes with beta2-YFP and clathrin even in the absence of an operational clathrin binding sequence. These findings argue against ARH and beta-arrestin binding to a site upon the beta2 appendage platform that is later obstructed by polymerized clathrin. We conclude that ARH and beta-arrestin depend on a privileged beta2 appendage site for proper cargo recruitment to clathrin

  20. Appendage patterning in the primitively wingless hexapods Thermobia domestica (Zygentoma: Lepismatidae) and Folsomia candida (Collembola: Isotomidae).

    PubMed

    Schaeper, Nina D; Wimmer, Ernst A; Prpic, Nikola-Michael

    2013-11-01

    Arthropod appendages are among the most diverse animal organs and have been adapted to a variety of functions. Due to this diversity, it can be difficult to recognize homologous parts in different appendage types and different species. Gene expression patterns of appendage development genes have been used to overcome this problem and to identify homologous limb portions across different species and their appendages. However, regarding the largest arthropod group, the hexapods, most of these studies focused on members of the winged insects (Pterygota), but primitively wingless groups like the springtails (Collembola) or silverfish and allies (Zygentoma) are underrepresented. We have studied the expression of a set of appendage patterning genes in the firebrat Thermobia domestica and the white springtail Folsomia candida. The expressions of Distal-less (Dll) and dachshund (dac) are generally similar to the patterns reported for pterygote insects. Modifications of gene regulation, for example, the lack of Dll expression in the palp of F. candida mouthparts, however, point to changes in gene function that can make the use of single genes and specific expression domains problematic for homology inference. Such hypotheses should therefore not rely on a small number of genes and should ideally also include information about gene function. The expression patterns of homothorax (hth) and extradenticle (exd) in both species are similar to the patterns of crustaceans and pterygote insects, but differ from those in chelicerates and myriapods. The proximal specificity of hth thus appears to trace from a common hexapod ancestor and also provides a link to the regulation of this gene in crustaceans.

  1. What Are the Signs and Symptoms of Atrial Fibrillation?

    MedlinePlus

    ... What Are the Signs and Symptoms of Atrial Fibrillation? Atrial fibrillation (AF) usually causes the heart's lower ... pain Dizziness or fainting Fatigue (tiredness) Confusion Atrial Fibrillation Complications AF has two major complications— stroke and ...

  2. Increased M1 Macrophages Infiltration Is Associated with Thrombogenesis in Rheumatic Mitral Stenosis Patients with Atrial Fibrillation

    PubMed Central

    Wang, Bingjian; Chen, Jianzhou; Li, Guannan; Zhu, Suhui; Xie, Jun; Xu, Biao

    2016-01-01

    Atrial fibrillation (AF) is the most common arrhythmia. In patients with AF, the role of macrophage subsets in thrombogenesis is unclear. In the present study, we analyzed the role of M1 and M2 macrophages and related cytokines in thrombogenesis of AF. Immunohistochemistry, Western blot, and TUNEL assay were used to detect M1/M2 macrophage infiltration, the expression pattern of IL-1β and inflammasome components, and apoptosis of cardiomyocytes in 71 specimens obtained from the left atrial appendage of patients with rheumatic mitral stenosis (MS) with or without thrombosis. We demonstrated that proinflammatory M1 macrophages were predominant in the atrium of MS patients with AF and thrombus. NLRP3 inflammasomes and IL-1β, which are primarily functional in macrophages, were activated in those patients. We also showed that increased cell death was associated with thrombogenesis in MS patients. These data indicate that infiltration of M1 macrophages and over-activation of NLRP3 inflammasomes may play a role in progressive atrial inflammation and thrombogenesis in rheumatic mitral stenosis patients with AF. PMID:26930272

  3. Novel nonpharmacologic approaches for stroke prevention in atrial fibrillation: results from clinical trials

    PubMed Central

    Proietti, Riccardo; Joza, Jacqueline; Arensi, Andrea; Levi, Michael; Russo, Vincenzo; Tzikas, Apostolos; Danna, Paolo; Sagone, Antonio; Viecca, Maurizio; Essebag, Vidal

    2015-01-01

    Atrial fibrillation (AF), the most common cardiac arrhythmia, confers a 5-fold risk of stroke that increases to 17-fold when associated with mitral stenosis. At this time, the most effective long-term solution to protect patients from stroke and thromboembolism is oral anticoagulation, either with vitamin K antagonists (VKAs) or a novel oral anticoagulant (NOAC). Despite the significant benefits they confer, both VKAs and NOACs are underused because of their increased potential for bleeding, and VKAs are underused because of their narrow therapeutic range, need for regular international normalized ratio checks, and interactions with food or medications. In patients with nonvalvular AF, approximately 90% of strokes originate from the left atrial appendage (LAA); in patients with rheumatic mitral valve disease, many patients (60%) have strokes that originate from the left atrium itself. Surgical LAA amputation or closure, although widely used to reduce stroke risk in association with cardiac surgery, is not currently performed as a stand-alone operation for stroke risk reduction because of its invasiveness. Percutaneous LAA closure, as an alternative to anticoagulation, has been increasingly used during the last decade in an effort to reduce stroke risk in nonvalvular AF. Several devices have been introduced during this time, of which one has demonstrated noninferiority compared with warfarin in a randomized controlled trial. This review describes the available technologies for percutaneous LAA closure, as well as a summary of the published trials concerning their safety and efficacy in reducing stroke risk in AF. PMID:25678828

  4. Present treatment options for atrial fibrillation

    PubMed Central

    Lairikyengbam, S; Anderson, M; Davies, A

    2003-01-01

    Atrial fibrillation is the commonest sustained cardiac arrhythmia. It accounts for >35% of all hospital admissions for cardiac arrhythmias in the United States. The presence of atrial fibrillation increases the mortality of a population by up to twofold. The risk of stroke increases from 1.5% in patients with atrial fibrillation from 50–59 years of age to up to 23.5% for such patients aged 80–89 years. Although the diagnosis of atrial fibrillation is usually straightforward, effective treatment is not. This article will discuss how rhythm control of atrial fibrillation can best be achieved, the controversy over the rhythm versus rate control, the maintenance of sinus rhythm with antiarrhythmic drugs after cardioversion, and prevention of thromboembolism. Finally, the recent advances in various non-pharmacological approaches for the treatment of atrial fibrillation will be highlighted. PMID:12612318

  5. [New developments for surgical ablation of atrial fibrillation].

    PubMed

    Hemmer, W; Böhm, J O

    2007-06-01

    The Cox-Maze procedure and less complex modifications have gained widespread use as a treatment modality for patients with concomitant atrial fibrillation. Hypothermic or hyperthermic energy sources play a significant role in rapidly creating linear lesions. Endocardial ablation is easy to perform and effective with different energy sources. Epicardial techniques may simplify the procedure by allowing surgery on a beating heart. But epicardial fat and the heat sink effect of the flowing endocardial blood are obstacles to effective ablation. New devices using bipolar (irrigated) radiofrequency, microwave or laser energy, cryoablation or focused ultrasound are in clinical or pre-clinical stages and permit lesions to be created on a beating heart without cardiopulmonary bypass. Minimally invasive or video-assisted surgical techniques and effective devices for epicardial ablation will enable the treatment of patients suffering from lone atrial fibrillation. To facilitate the comparison between different techniques and devices, guidelines for reporting clinical results are necessary.

  6. Almanac 2015: atrial fibrillation research in Heart

    PubMed Central

    Jawad-Ul-Qamar, Muhammad; Kirchhof, Paulus

    2016-01-01

    Atrial fibrillation continues to attract interest in the cardiovascular community and in Heart. Over 60 original research and review papers published in Heart in 2014–2015 cover various aspects of atrial fibrillation, from associated conditions and precipitating factors to new approaches to management. Here, we provide an overview of articles on atrial fibrillation published in Heart in 2014–2015, highlighting new developments, emerging concepts and novel approaches to treatment. PMID:26791994

  7. Assessment of atrial electromechanical interval using echocardiography after catheter ablation in patients with persistent atrial fibrillation

    PubMed Central

    Chen, Xiaodong; Chen, Minglong; Wang, Yingying; Yang, Bing; Ju, Weizhu; Zhang, Fengxiang; Cao, Kejiang

    2016-01-01

    Abstract We sought to investigate variation of atrial electromechanical interval after catheter ablation procedure in patients with persistent atrial fibrillation using pulse Doppler (PW) and pulse tissue Doppler imaging (PW-TDI). A total of 25 consecutive in-patients with persistent atrial fibrillation, who restored sinus rhythm after ablation procedure, were recruited in our cardiac center. Echocardiography was performed on each patient at 2 hours, 1 day, 5 days, 1 month and 3 months after the ablation therapy, and atrial electromechanical delay was measured simultaneously by PW and PW-TDI. There was no significant difference between PW and TDI in measuring atrial electromechanical delay. However, at postoperative 2 hours, peak A detection rates were mathematically but nonsignificantly greater by PW-TDI than by PW. Second, there was a significant decreasing trend in atrial electromechanical interval from postoperative 2 hours to 3 months, but only postoperative 2-hour atrial electromechanical interval was significantly greater than atrial electromechanical interval at other time. Lastly, patients without postoperative 2-hour atrial electromechanical interval had a significantly longer duration of atrial fibrillation as compared to those with postoperative 2-hour atrial electromechanical interval, by the PW or by PW-TDI, respectively. In patients with persistent atrial fibrillation, atrial electromechanical interval may decrease significantly within the first 24 hours after ablation but remain consistent later, and was significantly related to patients’ duration of atrial fibrillation. Atrial electromechanical interval, as a potential predicted factor, is recommended to be measured by either PW or TDI after 24 hours, when patients had recovered sinus rhythm by radiofrequency ablation. PMID:27924066

  8. A cellular, molecular, and pharmacological basis for appendage regeneration in mice

    PubMed Central

    Leung, Thomas H.; Snyder, Emily R.; Liu, Yinghua; Wang, Jing; Kim, Seung K.

    2015-01-01

    Regenerative medicine aims to restore normal tissue architecture and function. However, the basis of tissue regeneration in mammalian solid organs remains undefined. Remarkably, mice lacking p21 fully regenerate injured ears without discernable scarring. Here we show that, in wild-type mice following tissue injury, stromal-derived factor-1 (Sdf1) is up-regulated in the wound epidermis and recruits Cxcr4-expressing leukocytes to the injury site. In p21-deficient mice, Sdf1 up-regulation and the subsequent recruitment of Cxcr4-expressing leukocytes are significantly diminished, thereby permitting scarless appendage regeneration. Lineage tracing demonstrates that this regeneration derives from fate-restricted progenitor cells. Pharmacological or genetic disruption of Sdf1–Cxcr4 signaling enhances tissue repair, including full reconstitution of tissue architecture and all cell types. Our findings identify signaling and cellular mechanisms underlying appendage regeneration in mice and suggest new therapeutic approaches for regenerative medicine. PMID:26494786

  9. Patterned Anchorage to the Apical Extracellular Matrix Defines Tissue Shape in the Developing Appendages of Drosophila.

    PubMed

    Ray, Robert P; Matamoro-Vidal, Alexis; Ribeiro, Paulo S; Tapon, Nic; Houle, David; Salazar-Ciudad, Isaac; Thompson, Barry J

    2015-08-10

    How tissues acquire their characteristic shape is a fundamental unresolved question in biology. While genes have been characterized that control local mechanical forces to elongate epithelial tissues, genes controlling global forces in epithelia have yet to be identified. Here, we describe a genetic pathway that shapes appendages in Drosophila by defining the pattern of global tensile forces in the tissue. In the appendages, shape arises from tension generated by cell constriction and localized anchorage of the epithelium to the cuticle via the apical extracellular-matrix protein Dumpy (Dp). Altering Dp expression in the developing wing results in predictable changes in wing shape that can be simulated by a computational model that incorporates only tissue contraction and localized anchorage. Three other wing shape genes, narrow, tapered, and lanceolate, encode components of a pathway that modulates Dp distribution in the wing to refine the global force pattern and thus wing shape.

  10. The integumental appendages of the turtle shell: an evo-devo perspective.

    PubMed

    Moustakas-Verho, Jacqueline E; Cherepanov, Gennadii O

    2015-05-01

    The turtle shell is composed of dorsal armor (carapace) and ventral armor (plastron) covered by a keratinized epithelium. There are two epithelial appendages of the turtle shell: scutes (large epidermal shields separated by furrows and forming a unique mosaic) and tubercles (numerous small epidermal bumps located on the carapaces of some species). In our perspective, we take a synthetic, comparative approach to consider the homology and evolution of these integumental appendages. Scutes have been more intensively studied, as they are autapomorphic for turtles and can be diagnostic taxonomically. Their pattern of tessellation is stable phylogenetically, but labile in the individual. We discuss the history of developmental investigations of these structures and hypotheses of evolutionary and anomalous variation. In our estimation, the scutes of the turtle shell are an evolutionary novelty, whereas the tubercles found on the shells of some turtles are homologous to reptilian scales.

  11. Dynamics of a spacecraft with large flexible appendage constrained by multi-strut passive damper

    NASA Astrophysics Data System (ADS)

    Jia, Ying-Hong; Xu, Shi-Jie; Hu, Quan

    2013-04-01

    This paper is concerned with the dynamics of a spacecraft with multi-strut passive damper for large flexible appendage. The damper platform is connected to the spacecraft by a spheric hinge, multiple damping struts and a rigid strut. The damping struts provide damping forces while the rigid strut produces a motion constraint of the multibody system. The exact nonlinear dynamical equations in reducedorder form are firstly derived by using Kane's equation in matrix form. Based on the assumptions of small velocity and small displacement, the nonlinear equations are reduced to a set of linear second-order differential equations in terms of independent generalized displacements with constant stiffness matrix and damping matrix related to the damping strut parameters. Numerical simulation results demonstrate the damping effectiveness of the damper for both the motion of the spacecraft and the vibration of the flexible appendage, and verify the accuracy of the linear equations against the exact nonlinear ones.

  12. STS-74/MIR Photogrammetric Appendage Structural Dynamics Experiment Preliminary Data Analysis

    NASA Technical Reports Server (NTRS)

    Gilbert, Michael G.; Welch, Sharon S.; Pappa, Richard S.; Demeo, Martha E.

    1997-01-01

    The Photogrammetric Appendage Structural Dynamics Experiment was designed, developed, and flown to demonstrate and prove measurement of the structural vibration response of a Russian Space Station Mir solar array using photogrammetric methods. The experiment flew on the STS-74 Space Shuttle mission to Mir in November 1995 and obtained video imagery of solar array structural response to various excitation events. The video imagery has been digitized and triangulated to obtain response time history data at discrete points on the solar array. This data has been further processed using the Eigensystem Realization Algorithm modal identification technique to determine the natural vibration frequencies, damping, and mode shapes of the solar array. The results demonstrate that photogrammetric measurement of articulating, nonoptically targeted, flexible solar arrays and appendages is a viable, low-cost measurement option for the International Space Station.

  13. Patterned Anchorage to the Apical Extracellular Matrix Defines Tissue Shape in the Developing Appendages of Drosophila

    PubMed Central

    Ray, Robert P.; Matamoro-Vidal, Alexis; Ribeiro, Paulo S.; Tapon, Nic; Houle, David; Salazar-Ciudad, Isaac; Thompson, Barry J.

    2015-01-01

    Summary How tissues acquire their characteristic shape is a fundamental unresolved question in biology. While genes have been characterized that control local mechanical forces to elongate epithelial tissues, genes controlling global forces in epithelia have yet to be identified. Here, we describe a genetic pathway that shapes appendages in Drosophila by defining the pattern of global tensile forces in the tissue. In the appendages, shape arises from tension generated by cell constriction and localized anchorage of the epithelium to the cuticle via the apical extracellular-matrix protein Dumpy (Dp). Altering Dp expression in the developing wing results in predictable changes in wing shape that can be simulated by a computational model that incorporates only tissue contraction and localized anchorage. Three other wing shape genes, narrow, tapered, and lanceolate, encode components of a pathway that modulates Dp distribution in the wing to refine the global force pattern and thus wing shape. PMID:26190146

  14. MARCKS-Like Protein is an Initiating Molecule in Axolotl Appendage Regeneration

    PubMed Central

    Sugiura, Takuji; Wang, Heng; Barsacchi, Rico; Simon, Andras; Tanaka, Elly M.

    2016-01-01

    Identifying key molecules that launch regeneration has been a long sought goal. Multiple regenerative animals show an initial wound-associated proliferative response that transits into sustained proliferation if a significant portion of the body part has been removed 1-3. In the axolotl, appendage amputation initiates a round of wound-associated cell cycle induction followed by continued proliferation that is dependent on nerve-derived signals 4,5. A wound-associated molecule that triggers the initial proliferative response to launch regeneration has remained obscure. Using an expression cloning strategy followed by in vivo gain- and loss-of-function assays, we identified axolotl MARCKS like Protein (MLP) as an extracellularly released factor that induces the initial cell cycle response during axolotl appendage regeneration. PMID:26934225

  15. Comparative internal structure of dorsal lips and radiolar appendages in Sabellidae (Polychaeta) and phylogenetic implications.

    PubMed

    Capa, María; Nogueira, João Miguel de Matos; Rossi, Maíra Cappellani Silva

    2011-03-01

    Fan worms (Sabellidae) possess paired modified prostomial structures at the base of the radiolar crown, dorso-lateral to the mouth, called dorsal lips. The dorsal lips are involved in the sorting of particles collected by the radiolar crown. The range of variation in the morphology of dorsal lips is extensive, and probably this is not only due to adaptations to different environments and feeding preferences but also due to phylogenetic constraints. In this study, we describe and compare the morphology of dorsal lips in a range of sabellid taxa based on histological cross-sections of these structures, and compare our data and terminology with those of previous studies. Dorsal lips are maintained erect in most taxa by a modified radiole fused to them known as dorsal radiolar appendage. We suggest that dorsal radiolar appendages with an internal supporting axis (cellular or acellular) and probably also the ventral lips are synapomorphies of the family.

  16. Recurrent epiploic appendagitis and peritoneal dialysis: A case report and literature review

    PubMed Central

    Shrestha, Badri; Hampton, James

    2014-01-01

    Epiploic appendagitis (EA) is rare cause of acute or subacute abdominal pain in patients on peritoneal dialysis (PD), where the diagnosis can be challenging as the clinical features, laboratory markers and imaging characteristics have not been described previously in this group of patients. Here, we present the management of a case of EA in a patient on PD and review published literature pertinent to the subject. The importance of establishing the diagnosis early by laparoscopy is emphasised. PMID:25332903

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

    PubMed

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

    2015-07-01

    The causal relationship between atrial and ventricular activities during human atrial fibrillation (AF) is poorly understood. This study analyzed the effects of an increase in atrial rate on the link between atrial and ventricular activities during AF. Atrial and ventricular time series were determined in 14 patients during the spontaneous acceleration of the atrial rhythm at AF onset. The dynamic relationship between atrial and ventricular activities was quantified in terms of atrioventricular (AV) coupling by AV synchrogram analysis. The technique identified n:m coupling patterns (n atrial beats in m ventricular cycles), quantifying their percentage, maximal length, and conduction ratio (= m/n). Simulations with a difference-equation AV model were performed to correlate the observed dynamics to specific atrial/nodal properties. The atrial rate increase significantly affected AV coupling and ventricular response during AF. The shortening of atrial intervals from 185 ± 32 to 165 ± 24 ms (P < 0.001) determined transitions toward AV patterns with progressively decreasing m/n ratios (from conduction ratio = 0.34 ± 0.09 to 0.29 ± 0.08, P < 0.01), lower occurrence (from percentage of coupled beats = 27.1 ± 8.0 to 21.8 ± 6.9%, P < 0.05), and higher instability (from maximal length = 3.9 ± 1.5 to 2.8 ± 0.7 s, P < 0.01). Advanced levels of AV block and coupling instability at higher atrial rates were associated with increased ventricular interval variability (from 123 ± 52 to 133 ± 55 ms, P < 0.05). AV pattern transitions and coupling instability in patients were predicted, assuming the filtering of high-rate irregular atrial beats by the slow recovery of nodal excitability. These results support the role of atrial rate in determining AV coupling and ventricular response and may have implications for rate control in AF.

  18. Dynamic analysis of a system of hinge-connected rigid bodies with nonrigid appendages. [equations of motion

    NASA Technical Reports Server (NTRS)

    Likins, P. W.

    1974-01-01

    Equations of motion are derived for use in simulating a spacecraft or other complex electromechanical system amenable to idealization as a set of hinge-connected rigid bodies of tree topology, with rigid axisymmetric rotors and nonrigid appendages attached to each rigid body in the set. In conjunction with a previously published report on finite-element appendage vibration equations, this report provides a complete minimum-dimension formulation suitable for generic programming for digital computer numerical integration.

  19. Functional morphology of the male caudal appendages of the damselfly Ischnura elegans (Zygoptera: Coenagrionidae).

    PubMed

    Willkommen, Jana; Michels, Jan; Gorb, Stanislav N

    2015-07-01

    Odonata are usually regarded as one of the most ancient extant lineages of winged insects. Their copulatory apparatus and mating behavior are unique among insects. Male damselflies use their caudal appendages to clasp the female's prothorax during both copulation and egg-laying and have a secondary copulatory apparatus for sperm transfer. Knowledge of the functional morphology of the male caudal appendages is the basis for understanding the evolution of these structures in Odonata and respective organs in other insects. However, it is still not exactly known how the zygopteran claspers work. In this study, we applied micro-computed tomography and a variety of microscopy techniques to examine the morphology, surface microstructure, cuticle material composition and muscle topography of the male caudal appendages of Ischnura elegans. The results indicate that the closing of the paraproctal claspers is mainly passive. This indirect closing mechanism is very likely supported by high proportions of the elastic protein resilin present in the cuticle of the paraproctal bases. In addition, the prothoracic morphology of the female plays an important role in the indirect closing of the male claspers. Our data indicate that both structures - the male claspers and the female prothoracic hump - function together like a snap-fastener.

  20. Improbable appendages: Deer antler renewal as a unique case of mammalian regeneration.

    PubMed

    Kierdorf, Uwe; Li, Chunyi; Price, Joanna S

    2009-07-01

    Deer antlers are periodically replaced cranial appendages that develop from permanent outgrowths of the frontal bones known as pedicles. Antler re-growth is a unique regenerative event in mammals which in general are unable to replace bony appendages. Recent evidence suggests that antler regeneration is a stem cell-based process that depends on the activation of stem cells located in the pedicle periosteum which are presumed to be neural crest-derived. It has been demonstrated that several developmental pathways are involved in antler regeneration that are also known to play a role in the control of skeletal development and regeneration in other vertebrates. However, in contrast to most other natural examples of regeneration of complete body structures, antler regeneration apparently neither depends on a functional nerve supply nor involves a direct contact between wound epithelium and mesenchymal tissue. Antlers thus demonstrate that regeneration of a large bony appendage in a mammal can be achieved by a process that differs in certain aspects from epimorphic regeneration in lower vertebrates.

  1. Regulatory evolution of Tbx5 and the origin of paired appendages

    PubMed Central

    Adachi, Noritaka; Robinson, Molly; Goolsbee, Aden; Shubin, Neil H.

    2016-01-01

    The diversification of paired appendages has been a major factor in the evolutionary radiation of vertebrates. Despite its importance, an understanding of the origin of paired appendages has remained elusive. To address this problem, we focused on T-box transcription factor 5 (Tbx5), a gene indispensable for pectoral appendage initiation and development. Comparison of gene expression in jawless and jawed vertebrates reveals that the Tbx5 expression in jawed vertebrates is derived in having an expression domain that extends caudal to the heart and gills. Chromatin profiling, phylogenetic footprinting, and functional assays enabled the identification of a Tbx5 fin enhancer associated with this apomorphic pattern of expression. Comparative functional analysis of reporter constructs reveals that this enhancer activity is evolutionarily conserved among jawed vertebrates and is able to rescue the finless phenotype of tbx5a mutant zebrafish. Taking paleontological evidence of early vertebrates into account, our results suggest that the gain of apomorphic patterns of Tbx5 expression and regulation likely contributed to the morphological transition from a finless to finned condition at the base of the vertebrate lineage. PMID:27503876

  2. Atrial Arrhythmia Summit: Post Summit Report

    NASA Technical Reports Server (NTRS)

    Barr, Yael

    2010-01-01

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

  3. Left atrial myxoma masquerading as viral flu

    PubMed Central

    Chhabra, Lovely; Kiernan, Francis

    2016-01-01

    Atrial myxoma is a rare cardiac tumor that may be diagnosed incidentally on cardiac imaging or may present with life-threatening cardiac symptoms. We present a case of giant left atrial myxoma that presented as a flulike illness. PMID:27695187

  4. Giant right atrial thrombi treated with thrombolysis.

    PubMed

    Ruiz-Bailén, Manuel; López-Caler, Carmen; Castillo-Rivera, Ana; Rucabado-Aguilar, Luis; Ramos Cuadra, José Angel; Lara Toral, Juan; Lozano Cabezas, Cristobal; Fernández Guerrero, Juan Carlos

    2008-04-01

    The present report describes giant atrial thrombi that were treated with thrombolysis in a community hospital. Two patients with giant atrial thrombi whose treatment involved complications are presented. Both patients developed cardiogenic shock and were treated unsuccessfully with thrombolysis. Because thrombolysis of giant thrombi may be ineffective, patients in this situation may require surgery.

  5. Giant right atrial thrombi treated with thrombolysis

    PubMed Central

    Ruiz-Bailén, Manuel; López-Caler, Carmen; Castillo-Rivera, Ana; Rucabado-Aguilar, Luis; Cuadra, José Ángel Ramos; Toral, Juan Lara; Cabezas, Cristobal Lozano; Guerrero, Juan Carlos Fernández

    2008-01-01

    The present report describes giant atrial thrombi that were treated with thrombolysis in a community hospital. Two patients with giant atrial thrombi whose treatment involved complications are presented. Both patients developed cardiogenic shock and were treated unsuccessfully with thrombolysis. Because thrombolysis of giant thrombi may be ineffective, patients in this situation may require surgery. PMID:18401474

  6. A novel and simple atrial retractor.

    PubMed

    Kofidis, Theo; Lee, Chuen Neng

    2011-05-01

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

  7. Who Is at Risk for Atrial Fibrillation?

    MedlinePlus

    ... at Risk for Atrial Fibrillation? Atrial fibrillation (AF) affects millions of people, and the number is rising. Men are more ... conditions. It may act as a trigger in people who have other AF risk factors. Genetic factors also may play a role in causing AF. However, their role ... SITE INDEX ACCESSIBILITY PRIVACY STATEMENT FOIA OIG CONTACT ...

  8. Is there a synergic effect of propafenone associated with atrial overdrive pacing for atrial arrhythmia prevention? A randomised crossover study

    PubMed Central

    Garrigue, S; Barold, S; Cazeau, S; Hocini, M; Jais, P; Haissaguerre, M; Clementy, J

    2000-01-01

    OBJECTIVE—To assess the effect of adding propafenone to atrial overdrive for the prevention of atrial arrhythmia episodes in patients with DDD pacemakers.
DESIGN—22 patients (8 female, 14 male, mean (SD) age 67 (9) years, range 48 to 77) with DDD pacemakers and frequent paroxysmal atrial arrhythmia episodes were evaluated in a randomised crossover study.
SETTING—University hospital.
METHODS—Atrial overdrive was defined as a paced rate of 10 paced beats/min above the mean ventricular rate stored for the last 24 hours in the pacemaker memory function. The protocol consisted of two phases of one month each. The first phase consisted of atrial overdrive alone, while in the second phase, propafenone (600 mg/day) was added to atrial overdrive (atrial overdrive + propafenone). All 22 patients underwent the two phases in random order.
RESULTS—Mean ventricular rate was 72 (8) beats/min with atrial overdrive v 73 (6) with atrial overdrive + propafenone (NS). With atrial overdrive, 14 patients (64.6%) had no recorded atrial arrhythmia v 15 (68.2%) with atrial overdrive + propafenone (NS). There was no statistical difference between the atrial overdrive and atrial overdrive + propafenone phases with regard to the number of atrial arrhythmia episodes (14 (27) v 13 (28)), their total duration (30 (78) v 29 (63) h), and their maximum duration (41 (72) v 31 (58) min). However, in the brady-tachy subgroup with persistent atrial arrhythmias, atrial overdrive + propafenone produced a shorter mean cumulative duration of atrial arrhythmia than atrial overdrive (104 (115) v 178 (149) h, p = 0.04), with a significant decrease in the number of atrial arrhythmia episodes (134 (98) v 102 (83), p = 0.05). The proportion of asymptomatic atrial arrhythmia episodes increased only in the AV block group during atrial overdrive + propafenone (p = 0.03). Three patients had atrial arrhythmias during atrial overdrive + propafenone but not

  9. Ionic remodeling underlying action potential changes in a canine model of atrial fibrillation.

    PubMed

    Yue, L; Feng, J; Gaspo, R; Li, G R; Wang, Z; Nattel, S

    1997-10-01

    Rapid electrical activation, as occurs during atrial fibrillation (AF), is known to cause reductions in atrial refractoriness and in adaptation to heart rate of the atrial refractory period, which promote the maintenance of AF, but the underlying ionic mechanisms are unknown. In order to determine the cellular and ionic changes caused by chronic atrial tachycardia, we studied right atrial myocytes from dogs subjected to 1, 7, or 42 days of atrial pacing at 400/min and compared them with myocytes from sham-operated dogs (pacemaker inserted but not activated). Rapid pacing led to progressive increases in the duration of AF induced by bursts of 10-Hz stimuli (from 3 +/- 2 seconds in sham-operated dogs to 3060 +/- 707 seconds in dogs after 42 days of pacing, P < .001) and reduced atrial refractoriness and adaptation to rate of the atrial refractory period. Voltage-clamp studies showed that chronic rapid pacing did not alter inward rectifier K+ current, rapid or slow components of the delayed rectifier current, the ultrarapid delayed rectifier current, T-type Ca2+ current, or Ca(2+)-dependent Cl- current. In contrast, the densities of transient outward current (Ito) and L-type Ca2+ current (ICa) were progressively reduced as the duration of rapid pacing increased, without concomitant changes in kinetics or voltage dependence. In keeping with in vivo changes in refractoriness, action potential duration (APD) and APD adaptation to rate were decreased by rapid pacing. The response of the action potential and ionic currents flowing during the action potential (as exposed by action-potential voltage clamp) to nifedipine in normal canine cells and in cells from rapidly paced dogs suggested that the APD changes in paced dogs were largely due to reductions in ICa. We conclude that sustained atrial tachycardia reduces Ito and ICa, that the reduced ICa decreases APD and APD adaptation to rate, and that these cellular changes likely account for the alterations in atrial

  10. The Spatiotemporal Stability of Dominant Frequency Sites in In-Silico Modeling of 3-Dimensional Left Atrial Mapping of Atrial Fibrillation

    PubMed Central

    Hwang, Minki; Song, Jun-Seop; Lee, Young-Seon; Joung, Boyoung; Pak, Hui-Nam

    2016-01-01

    Background We previously reported that stable rotors were observed in in-silico human atrial fibrillation (AF) models, and were well represented by dominant frequency (DF). We explored the spatiotemporal stability of DF sites in 3D-AF models imported from patient CT images of the left atrium (LA). Methods We integrated 3-D CT images of the LA obtained from ten patients with persistent AF (male 80%, 61.8 ± 13.5 years old) into an in-silico AF model. After induction, we obtained 6 seconds of AF simulation data for DF analyses in 30 second intervals (T1–T9). The LA was divided into ten sections. Spatiotemporal changes and variations in the temporal consistency of DF were evaluated at each section of the LA. The high DF area was defined as the area with the highest 10% DF. Results 1. There was no spatial consistency in the high DF distribution at each LA section during T1–T9 except in one patient (p = 0.027). 2. Coefficients of variation for the high DF area were highly different among the ten LA sections (p < 0.001), and they were significantly higher in the four pulmonary vein (PV) areas, the LA appendage, and the peri-mitral area than in the other LA sections (p < 0.001). 3. When we conducted virtual ablation of 10%, 15%, and 20% of the highest DF areas (n = 270 cases), AF was changed to atrial tachycardia (AT) or terminated at a rate of 40%, 57%, and 76%, respectively. Conclusions Spatiotemporal consistency of the DF area was observed in 10% of AF patients, and high DF areas were temporally variable. Virtual ablation of DF is moderately effective in AF termination and AF changing into AT. PMID:27459377

  11. Bacterial Surface Appendages Strongly Impact Nanomechanical and Electrokinetic Properties of Escherichia coli Cells Subjected to Osmotic Stress

    PubMed Central

    Francius, Grégory; Polyakov, Pavel; Merlin, Jenny; Abe, Yumiko; Ghigo, Jean-Marc; Merlin, Christophe; Beloin, Christophe; Duval, Jérôme F. L.

    2011-01-01

    The physicochemical properties and dynamics of bacterial envelope, play a major role in bacterial activity. In this study, the morphological, nanomechanical and electrohydrodynamic properties of Escherichia coli K-12 mutant cells were thoroughly investigated as a function of bulk medium ionic strength using atomic force microscopy (AFM) and electrokinetics (electrophoresis). Bacteria were differing according to genetic alterations controlling the production of different surface appendages (short and rigid Ag43 adhesins, longer and more flexible type 1 fimbriae and F pilus). From the analysis of the spatially resolved force curves, it is shown that cells elasticity and turgor pressure are not only depending on bulk salt concentration but also on the presence/absence and nature of surface appendage. In 1 mM KNO3, cells without appendages or cells surrounded by Ag43 exhibit large Young moduli and turgor pressures (∼700–900 kPa and ∼100–300 kPa respectively). Under similar ionic strength condition, a dramatic ∼50% to ∼70% decrease of these nanomechanical parameters was evidenced for cells with appendages. Qualitatively, such dependence of nanomechanical behavior on surface organization remains when increasing medium salt content to 100 mM, even though, quantitatively, differences are marked to a much smaller extent. Additionally, for a given surface appendage, the magnitude of the nanomechanical parameters decreases significantly when increasing bulk salt concentration. This effect is ascribed to a bacterial exoosmotic water loss resulting in a combined contraction of bacterial cytoplasm together with an electrostatically-driven shrinkage of the surface appendages. The former process is demonstrated upon AFM analysis, while the latter, inaccessible upon AFM imaging, is inferred from electrophoretic data interpreted according to advanced soft particle electrokinetic theory. Altogether, AFM and electrokinetic results clearly demonstrate the intimate

  12. Bacterial surface appendages strongly impact nanomechanical and electrokinetic properties of Escherichia coli cells subjected to osmotic stress.

    PubMed

    Francius, Grégory; Polyakov, Pavel; Merlin, Jenny; Abe, Yumiko; Ghigo, Jean-Marc; Merlin, Christophe; Beloin, Christophe; Duval, Jérôme F L

    2011-01-01

    The physicochemical properties and dynamics of bacterial envelope, play a major role in bacterial activity. In this study, the morphological, nanomechanical and electrohydrodynamic properties of Escherichia coli K-12 mutant cells were thoroughly investigated as a function of bulk medium ionic strength using atomic force microscopy (AFM) and electrokinetics (electrophoresis). Bacteria were differing according to genetic alterations controlling the production of different surface appendages (short and rigid Ag43 adhesins, longer and more flexible type 1 fimbriae and F pilus). From the analysis of the spatially resolved force curves, it is shown that cells elasticity and turgor pressure are not only depending on bulk salt concentration but also on the presence/absence and nature of surface appendage. In 1 mM KNO(3), cells without appendages or cells surrounded by Ag43 exhibit large Young moduli and turgor pressures (∼700-900 kPa and ∼100-300 kPa respectively). Under similar ionic strength condition, a dramatic ∼50% to ∼70% decrease of these nanomechanical parameters was evidenced for cells with appendages. Qualitatively, such dependence of nanomechanical behavior on surface organization remains when increasing medium salt content to 100 mM, even though, quantitatively, differences are marked to a much smaller extent. Additionally, for a given surface appendage, the magnitude of the nanomechanical parameters decreases significantly when increasing bulk salt concentration. This effect is ascribed to a bacterial exoosmotic water loss resulting in a combined contraction of bacterial cytoplasm together with an electrostatically-driven shrinkage of the surface appendages. The former process is demonstrated upon AFM analysis, while the latter, inaccessible upon AFM imaging, is inferred from electrophoretic data interpreted according to advanced soft particle electrokinetic theory. Altogether, AFM and electrokinetic results clearly demonstrate the intimate

  13. Atrial septal defect repair gone wrong.

    PubMed

    Bloomingdale, Richard; Ashraf, Said; Cardozo, Shaun

    2017-02-01

    Isolated atrial septal defect (ASD) accounts for 13% of congenital heart disorders. The anatomic location, size, and coexistence of other cardiac anomalies determine outcomes of repair. Surgical closure was the first-choice treatment until the 1990s and remains the only treatment for large defects. We describe a case of a 64-year-old woman who underwent surgical repair for an ASD as a child in 1959. She presented with dyspnea to the hospital almost 53 years after the surgery. Diagnostic cardiac imaging revealed interesting anatomy of the repair surgery. Transthoracic echocardiography showed areas of flow signal across the patch consistent with surgical perforation of the patch to reduce symptoms of superior vena cava (SVC) syndrome. Despite intervention, severe dilation of the SVC along with a thrombus is seen. CT angiography of the heart showed the ASD patch occluding the ostium of the SVC instead of patching the ASD. Transesophageal echocardiography showed malpositioned patch allowing the sinus venosus ASD to remain patent.

  14. H2S inhibits angiotensin II-induced atrial Kv1.5 upregulation by attenuating Nox4-mediated ROS generation during atrial fibrillation.

    PubMed

    Lu, Guihua; Xu, Chenggui; Tang, Kaiyu; Zhang, Juhong; Li, Qinglang; Peng, Longyun; Wang, Yesong; Huang, Zhibin; Gao, Xiuren

    2017-01-29

    Our previous study demonstrated that angiotensin II (Ang II) upregulates the expression of Kv1.5, a promising target for atrial fibrillation (AF) therapy, by activating ROS-dependent P-Smad2/3 and P-ERK 1/2. A recent study showed that hydrogen sulfide (H2S) may modulate the effects of angiotensin II (Ang II) by inhibiting the NADPH oxidase 4 (Nox4)-ROS signaling in the heart. The present study aimed to determine whether H2S is involved in the regulation of atrial Kv1.5 via ROS-related mechanisms in AF. Cultured neonatal rat atrial myocytes and a beagle model of AF were used for this study. In the neonatal rat atrial myocytes, quantitative PCR and enzyme immunoassays revealed that the mRNA expression levels of angiotensinogen, angiotensin-converting enzyme, and Ang II type I receptor (AT1R) and the Ang II supernatant concentration were significantly increased by hydrogen peroxide (H2O2) incubation, and these H2O2-induced alterations were reversed by diphenyleneiodonium, apocynin and H2S supplementation. Flow cytometry and Western blotting revealed that blockade of H2S biosynthesis using dl-propargylglycine increased ROS production and the expression of Ang II and Kv1.5. Sodium hydrosulfide (an exogenous H2S donor) and Nox4 siRNA inhibited Ang II-induced ROS production and Ang II-induced expression of Kv1.5, P-Smad2/3, P-ERK 1/2. Sodium hydrosulfide suppressed the Ang II-induced upregulation of Nox4. In our beagle AF model, 24 h of rapid atrial pacing (RAP) increased the atrial Ang II concentration, ROS production and the protein expression of Nox4, Kv1.5, P-Smad2/3 and P-ERK 1/2. These RAP-induced changes were inhibited by H2S supplementation and losartan (an AT1R blocker) pretreatment. In conclusion, our study indicates that H2S downregulates Ang II-induced atrial Kv1.5 expression by attenuating Nox4-related ROS-triggered P-Smad2/3 and P-ERK 1/2 activation during AF. H2S supplementation would be beneficial for AF treatment via the suppression of atrial Kv1

  15. Towards Low Energy Atrial Defibrillation.

    PubMed

    Walsh, Philip; Kodoth, Vivek; McEneaney, David; Rodrigues, Paola; Velasquez, Jose; Waterman, Niall; Escalona, Omar

    2015-09-03

    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. Efficient

  16. Towards Low Energy Atrial Defibrillation

    PubMed Central

    Walsh, Philip; Kodoth, Vivek; McEneaney, David; Rodrigues, Paola; Velasquez, Jose; Waterman, Niall; Escalona, Omar

    2015-01-01

    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 intracardiacimpedance (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. Efficient

  17. Atrial flutter a manifestation of cardiac tamponade.

    PubMed

    Pabón, Guillermo Mora; Ramírez, John A

    2012-04-01

    Atrial flutter (AFL) is a common arrhythmia that is associated with postpericardiotomy and pericarditis. The relationship of AFL with tamponade has rarely been reported. A case of AFL with acute pericarditis and cardiac tamponade is thus presented here.

  18. Atrial fibrillation in elderly: particularities of management.

    PubMed

    Alexa, Ioana Dana; Bucur, Ionela Mirela; Rusu, R I; Ungureanu, G

    2009-01-01

    Atrial fibrillation (AF), a common and serious cardiac rhythm disturbance, is responsible for substantial morbidity and mortality in the population. Currently about 2.3 million people in the US are diagnosed with AF and, based of the US census, this number is expected to rise to 5.6 million by 2050. It doubles in prevalence with each decade of age, reaching almost 9% at age 80-89 years. It has increased in prevalence over the calendar decades, reaching 'epidemic' proportions. The risk of stroke increases from 1.5% in patients with atrial fibrillation from 50-59 years of age to up to 23.5% for such patients aged 80-89 years. Although the diagnosis of atrial fibrillation is usually straightforward, effective treatment is not. We aimed to discuss how rhythm control of atrial fibrillation can best be achieved in elderly patients, the controversy over the rhythm versus rate control, and prevention of thromboembolism.

  19. Atrial Fibrillation During an Exploration Class Mission

    NASA Technical Reports Server (NTRS)

    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.

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

    PubMed

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

    2014-06-01

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

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

    PubMed

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

    2008-12-01

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

  2. Arterial embolism in thyrotoxicosis with atrial fibrillation.

    PubMed Central

    Staffurth, J S; Gibberd, M C; Fui, S N

    1977-01-01

    In 262 patients with thyrotoxicosis and atrial fibrillation there were 26 episodes of arterial embolism (17 cerebral and nine elsewhere) in 21 patients. Twelve incidents occurred with active thyrotoxicosis, three on reversion to sinus rhythm, and 11 after the patients were euthyroid. This important complication is more common than is realised, and most patients should be put on prophylactic anticoagulants when first seen with atrial fibrillation. PMID:902055

  3. Atrial fibrillation cardioversion following acupuncture

    PubMed Central

    Dilber, Dario; Čerkez-Habek, Jasna; Barić, Hrvoje; Gradišer, Marina

    2015-01-01

    Atrial fibrillation (AF) is the most common arrhythmia and it is an independent risk for serious events. Acupuncture has been growing in popularity in the West, and there are reports of its benefits in treating AF. We report a 57-year-old man who was admitted after having an allergic reaction to amiodarone administered to treat paroxysmal AF with fast ventricular response. Cardioversion with intravenous propafenone was uneventful. Before an attempt of electric cardioversion, he was treated with acupuncture as additional therapy to peroral propafenone. After acupuncture treatment consisting of 10 treatments during 30 days period, both immediate cardioversion to sinus rhythm and no paroxysmal AF during 30 days period were recorded. PMID:26593171

  4. Gene signatures of postoperative atrial fibrillation in atrial tissue after coronary artery bypass grafting surgery in patients receiving β-blockers.

    PubMed

    Kertai, Miklos D; Qi, Wenjing; Li, Yi-Ju; Lombard, Frederick W; Liu, Yutao; Smith, Michael P; Stafford-Smith, Mark; Newman, Mark F; Milano, Carmelo A; Mathew, Joseph P; Podgoreanu, Mihai V

    2016-03-01

    Atrial tissue gene expression profiling may help to determine how differentially expressed genes in the human atrium before cardiopulmonary bypass (CPB) are related to subsequent biologic pathway activation patterns, and whether specific expression profiles are associated with an increased risk for postoperative atrial fibrillation (AF) or altered response to β-blocker (BB) therapy after coronary artery bypass grafting (CABG) surgery. Right atrial appendage (RAA) samples were collected from 45 patients who were receiving perioperative BB treatment, and underwent CABG surgery. The isolated RNA samples were used for microarray gene expression analysis, to identify probes that were expressed differently in patients with and without postoperative AF. Gene expression analysis was performed to identify probes that were expressed differently in patients with and without postoperative AF. Gene set enrichment analysis (GSEA) was performed to determine how sets of genes might be systematically altered in patients with postoperative AF. Of the 45 patients studied, genomic DNA from 42 patients was used for target sequencing of 66 candidate genes potentially associated with AF, and 2,144 single-nucleotide polymorphisms (SNPs) were identified. We then performed expression quantitative trait loci (eQTL) analysis to determine the correlation between SNPs identified in the genotyped patients, and RAA expression. Probes that met a false discovery rate<0.25 were selected for eQTL analysis. Of the 17,678 gene expression probes analyzed, 2 probes met our prespecified significance threshold of false discovery rate<0.25. The most significant probe corresponded to vesicular overexpressed in cancer - prosurvival protein 1 gene (VOPP1; 1.83 fold change; P=3.47×10(-7)), and was up-regulated in patients with postoperative AF, whereas the second most significant probe, which corresponded to the LOC389286 gene (0.49 fold change; P=1.54×10(-5)), was down-regulated in patients with

  5. Designing Comparative Effectiveness Trials of Surgical Ablation for Atrial Fibrillation: Experience of the Cardiothoracic Surgical Trials Network

    PubMed Central

    Gillinov, A. Marc; Argenziano, Michael; Blackstone, Eugene H.; Iribarne, Alexander; DeRose, Joseph J.; Ailawadi, Gorav; Russo, Mark J.; Ascheim, Deborah D.; Parides, Michael K.; Rodriguez, Evelio; Bouchard, Denis; Taddei-Peters, Wendy C.; Geller, Nancy L.; Acker, Michael A.; Gelijns, Annetine C.

    2013-01-01

    Background Since the introduction of the cut-and-sew Cox-Maze procedure for atrial fibrillation (AF) there has been substantial innovation in techniques for ablation. Use of alternate energy sources for ablation simplified the procedure and has resulted in dramatic increase in the number of AF patients treated by surgical ablation. Despite its increasingly widespread adoption, there is lack of rigorous clinical evidence to establish this as an effective clinical therapy. Methods and Results This paper describes a comparative effectiveness randomized trial, supported by the Cardiothoracic Surgical Trials Network, of surgical ablation with left atrial appendage (LAA) closure versus LAA closure alone in patients with persistent and longstanding persistent AF undergoing mitral valve surgery. Nested within this trial, is a further randomized comparison of 2 different lesions sets: pulmonary vein isolation and full Maze lesion set. This paper addresses trial design challenges, including how to best characterize the target population, operationalize freedom from AF as a primary endpoint, account for the impact of anti-arrhythmic drugs, and measure and analyze secondary endpoints, such as post-operative AF load. Conclusions This paper concludes by discussing how insights that emerge from this trial may affect surgical practice and guide future research in this area. PMID:21616507

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Antithrombotic treatment of atrial fibrillation: new insights.

    PubMed

    Le Heuzey, J Y

    2012-10-01

    The incidence and prevalence of atrial fibrillation are quickly increasing, mainly due to the ageing of the population. Atrial fibrillation is, to date, a problem of public health. Atrial fibrillation is associated to a five-fold risk of stroke, which may be identified by score risks, such as CHADS(2) score. The classical antithrombotic treatment of atrial fibrillation is based on vitamin K antagonists. Trials made in the 90's have clearly shown that vitamin K antagonists were able to decrease stroke risk by about 60%. New oral anticoagulants are now available on the market to treat patients with atrial fibrillation. These drugs are dabigatran which has demonstrated an interest in the RE-LY trial. Two doses may be prescribed, 110 mg bid and 150 mg bid. Anti Xa have also demonstrated an interest : rivaroxaban in the ROCKET AF trial and apixaban in the AVERROES (versus aspirin) and ARISTOTLE trials. In the future these drugs will have a major place in the armamentarium used to treat patients with atrial fibrillation. In all these trials a decrease in intra cranial haemorrhages has been demonstrated. In the everyday practice it will be necessary to be very cautious in patients with impaired renal function, as all these drugs are eliminated by kidneys.

  8. Cis-regulatory programs in the development and evolution of vertebrate paired appendages

    PubMed Central

    Gehrke, Andrew R.; Shubin, Neil H.

    2017-01-01

    Differential gene expression is the core of development, mediating the genetic changes necessary for determining cell identity. The regulation of gene activity by cis-acting elements (e.g., enhancers) is a crucial mechanism for determining differential gene activity by precise control of gene expression in embryonic space and time. Modifications to regulatory regions can have profound impacts on phenotype, and therefore developmental and evolutionary biologists have increasingly focused on elucidating the transcriptional control of genes that build and pattern body plans. Here, we trace the evolutionary history of transcriptional control of three loci key to vertebrate appendage development (Fgf8, Shh, and HoxD/A). Within and across these regulatory modules, we find both complex and flexible regulation in contrast with more fixed enhancers that appear unchanged over vast timescales of vertebrate evolution. The transcriptional control of vertebrate appendage development was likely already incredibly complex in the common ancestor of fish, implying that subtle changes to regulatory networks were more likely responsible for alterations in phenotype rather than the de novo addition of whole regulatory domains. Finally, we discuss the dangers of relying on inter-species transgenesis when testing enhancer function, and call for more controlled regulatory swap experiments when inferring the evolutionary history of enhancer elements. PMID:26783722

  9. Analytical method for the attitude stability of partially liquid filled spacecraft with flexible appendage

    NASA Astrophysics Data System (ADS)

    Yan, Yulong; Yue, Baozeng

    2017-02-01

    In this paper, the attitude stability of liquid-filled spacecraft with flexible appendage is investigated. The motion of liquid sloshing is modeled as the spherical pendulum, and the flexible appendage is approached by a linear shearing beam. Nonlinear dynamic equations of the coupled system are derived from the Hamiltonian. The stability of the coupled system was analyzed by using the energy-Casimir method, and the nonlinear stability theorem of the coupled spacecraft system was also obtained. Through numerical computation, the correctness of the proposed theorem is verified and the boundary curves of the stable region are presented. The increase of the angular velocity and flexible attachment length will weaken the attitude stability, and the change of the filled ratio of liquid fuel tank has a different influence on the stability of the coupled spacecraft, depending on the different conditions. The attitude stability analysis of the coupled spacecraft system in this context is useful for selecting appropriate parameters in the complex spacecraft design.

  10. Effects of environmental factors and appendage injury on the wing variation in the cricket Velarifictorus ornatus.

    PubMed

    Zhao, Lü-Quan; Zhu, Dao-Hong

    2014-01-01

    The effects of environmental factors and appendage injury on the wing variation in Velarifictorus ornatus (Shiraki) (Orthoptera: Gryllidae) were investigated. The percentage of micropters was more than 95% when the nymphs were reared at constant photoperiods, and changing photoperiod did not affect wing variation in V. ornatus at 25 or 30°C. In the crowding experiment, the percentage of macropters was only 11.2% when the nymphs were reared separately at 25°C. In contrast, the percentage of macropters was significantly higher when the rearing density was increased to two nymphs per container and lower when the rearing density was increased to five or 10 nymphs per container. These results indicate that low and high rearing densities induce micropters, but intermediate rearing density stimulates the formation of macropters. Meanwhile, severance of appendages, such as antennae, femora, and tibiae, in the nymph stage exerted a micropterizing effect. The period sensitive to such stresses ranged from 35 to 60 days of nymph development.

  11. Trichohyalin-like proteins have evolutionarily conserved roles in the morphogenesis of skin appendages.

    PubMed

    Mlitz, Veronika; Strasser, Bettina; Jaeger, Karin; Hermann, Marcela; Ghannadan, Minoo; Buchberger, Maria; Alibardi, Lorenzo; Tschachler, Erwin; Eckhart, Leopold

    2014-11-01

    S100 fused-type proteins (SFTPs) such as filaggrin, trichohyalin, and cornulin are differentially expressed in cornifying keratinocytes of the epidermis and various skin appendages. To determine evolutionarily conserved, and thus presumably important, features of SFTPs, we characterized nonmammalian SFTPs and compared their amino acid sequences and expression patterns with those of mammalian SFTPs. We identified an ortholog of cornulin and a previously unknown SFTP, termed scaffoldin, in reptiles and birds, whereas filaggrin was confined to mammals. In contrast to mammalian SFTPs, both cornulin and scaffoldin of the chicken are expressed in the embryonic periderm. However, scaffoldin resembles mammalian trichohyalin with regard to its expression in the filiform papillae of the tongue and in the epithelium underneath the forming tips of the claws. Furthermore, scaffoldin is expressed in the epithelial sheath around growing feathers, reminiscent of trichohyalin expression in the inner root sheath of hair. The results of this study show that SFTP-positive epithelia function as scaffolds for the growth of diverse skin appendages such as claws, nails, hair, and feathers, indicating a common evolutionary origin.

  12. Effect of Red Clover Isoflavones over Skin, Appendages, and Mucosal Status in Postmenopausal Women

    PubMed Central

    Lipovac, Markus; Chedraui, Peter; Gruenhut, Christine; Gocan, Anca; Kurz, Christine; Neuber, Benedikt; Imhof, Martin

    2011-01-01

    Objective. Evaluate in postmenopausal women the effect of red clover extract (RCE) isoflavones over subjective status of skin, appendages, and several mucosal sites. Method. Postmenopausal women (n = 109) were randomly assigned to receive either two daily capsules of the active compound (80 mg RCE, Group A) or placebo of equal appearance (Group B) for a 90-day period. After a washout period of 7 days, medication was crossed over and taken for 90 days more. Subjective improvement of skin, appendages, and several mucosal site status was assessed for each studied group at 90 and 187 days using a visual analogue scale (VAS). In addition, libido, tiredness, and urinary, sleep, and mood complaints were also evaluated. Results. Women after RCE intervention (both groups) reported better subjective improvement of scalp hair and skin status, libido, mood, sleep, and tiredness. Improvement of urinary complaints, nail, body hair, and mucosa (oral, nasal, and ocular) status did not differ between treatment phases (intra- and intergroup). Overall satisfaction with treatment was reported higher after RCE intervention (both groups) as compared to placebo. Conclusion. RCE supplementation exerted a subject improvement of scalp hair and skin status as well as libido, mood, sleep, and tiredness in postmenopausal women. PMID:22135679

  13. Structural properties of the tubular appendage spinae from marine bacterium Roseobacter sp. strain YSCB

    PubMed Central

    Bernadac, A.; Wu, L.-F.; Santini, C.-L.; Vidaud, C.; Sturgis, J. N.; Menguy, N.; Bergam, P.; Nicoletti, C.; Xiao, T.

    2012-01-01

    Spinae are tubular surface appendages broadly found in Gram-negative bacteria. Little is known about their architecture, function or origin. Here, we report structural characterization of the spinae from marine bacteria Roseobacter sp. YSCB. Electron cryo-tomography revealed that a single filament winds into a hollow flared base with progressive change to a cylinder. Proteinase K unwound the spinae into proteolysis-resistant filaments. Thermal treatment ripped the spinae into ribbons that were melted with prolonged heating. Circular dichroism spectroscopy revealed a dominant beta-structure of the spinae. Differential scanning calorimetry analyses showed three endothermic transformations at 50–85°C, 98°C and 123°C, respectively. The heating almost completely disintegrated the spinae, abolished the 98°C transition and destroyed the beta-structure. Infrared spectroscopy identified the amide I spectrum maximum at a position similar to that of amyloid fibrils. Therefore, the spinae distinguish from other bacterial appendages, e.g. flagella and stalks, in both the structure and mechanism of assembly. PMID:23230515

  14. Effect of Red Clover Isoflavones over Skin, Appendages, and Mucosal Status in Postmenopausal Women.

    PubMed

    Lipovac, Markus; Chedraui, Peter; Gruenhut, Christine; Gocan, Anca; Kurz, Christine; Neuber, Benedikt; Imhof, Martin

    2011-01-01

    Objective. Evaluate in postmenopausal women the effect of red clover extract (RCE) isoflavones over subjective status of skin, appendages, and several mucosal sites. Method. Postmenopausal women (n = 109) were randomly assigned to receive either two daily capsules of the active compound (80 mg RCE, Group A) or placebo of equal appearance (Group B) for a 90-day period. After a washout period of 7 days, medication was crossed over and taken for 90 days more. Subjective improvement of skin, appendages, and several mucosal site status was assessed for each studied group at 90 and 187 days using a visual analogue scale (VAS). In addition, libido, tiredness, and urinary, sleep, and mood complaints were also evaluated. Results. Women after RCE intervention (both groups) reported better subjective improvement of scalp hair and skin status, libido, mood, sleep, and tiredness. Improvement of urinary complaints, nail, body hair, and mucosa (oral, nasal, and ocular) status did not differ between treatment phases (intra- and intergroup). Overall satisfaction with treatment was reported higher after RCE intervention (both groups) as compared to placebo. Conclusion. RCE supplementation exerted a subject improvement of scalp hair and skin status as well as libido, mood, sleep, and tiredness in postmenopausal women.

  15. An armoured Cambrian lobopodian from China with arthropod-like appendages.

    PubMed

    Liu, Jianni; Steiner, Michael; Dunlop, Jason A; Keupp, Helmut; Shu, Degan; Ou, Qiang; Han, Jian; Zhang, Zhifei; Zhang, Xingliang

    2011-02-24

    Cambrian fossil Lagerstätten preserving soft-bodied organisms have contributed much towards our understanding of metazoan origins. Lobopodians are a particularly interesting group that diversified and flourished in the Cambrian seas. Resembling 'worms with legs', they have long attracted much attention in that they may have given rise to both Onychophora (velvet worms) and Tardigrada (water bears), as well as to arthropods in general. Here we describe Diania cactiformis gen. et sp. nov. as an 'armoured' lobopodian from the Chengjiang fossil Lagerstätte (Cambrian Stage 3), Yunnan, southwestern China. Although sharing features with other typical lobopodians, it is remarkable for possessing robust and probably sclerotized appendages, with what appear to be articulated elements. In terms of limb morphology it is therefore closer to the arthropod condition, to our knowledge, than any lobopodian recorded until now. Phylogenetic analysis recovers it in a derived position, close to Arthropoda; thus, it seems to belong to a grade of organization close to the point of becoming a true arthropod. Further, D. cactiformis could imply that arthropodization (sclerotization of the limbs) preceded arthrodization (sclerotization of the body). Comparing our fossils with other lobopodian appendage morphologies--see Kerygmachela, Jianshanopodia and Megadictyon--reinforces the hypothesis that the group as a whole is paraphyletic, with different taxa expressing different grades of arthropodization.

  16. Connexins and pannexins in the integumentary system: the skin and appendages.

    PubMed

    Faniku, Chrysovalantou; Wright, Catherine S; Martin, Patricia E

    2015-08-01

    The integumentary system comprises the skin and its appendages, which includes hair, nails, feathers, sebaceous and eccrine glands. In this review, we focus on the expression profile of connexins and pannexins throughout the integumentary system in mammals, birds and fish. We provide a picture of the complexity of the connexin/pannexin network illustrating functional importance of these proteins in maintaining the integrity of the epidermal barrier. The differential regulation and expression of connexins and pannexins during skin renewal, together with a number of epidermal, hair and nail abnormalities associated with mutations in connexins, emphasize that the correct balance of connexin and pannexin expression is critical for maintenance of the skin and its appendages with both channel and non-channel functions playing profound roles. Changes in connexin expression during both hair and feather regeneration provide suggestions of specialized communication compartments. Finally, we discuss the potential use of zebrafish as a model for connexin skin biology, where evidence mounts that differential connexin expression is involved in skin patterning and pigmentation.

  17. Long-term outcome of patients with triphasic mitral flow with a mid-diastolic L wave: prognostic role of left atrial volume and N-terminal pro-brain natriuretic peptide.

    PubMed

    Kim, Sung-Ai; Son, Jungwoo; Shim, Chi-Young; Choi, Eui-Young; Ha, Jong-Won

    2017-03-27

    A mid-diastolic L wave has been recognized as a marker of advanced left ventricular (LV) diastolic dysfunction. However, its prognostic implication is unclear. This study assessed long-term prognosis and independent predictors of adverse outcomes in patients with a mid-diastolic L wave. A total of 144 consecutive patients (mean age 63 ± 12 years, 88 female) with a mid-diastolic L wave of ≥0.2 m/s and in sinus rhythm were identified. Patients with significant valvular heart disease, low LV ejection fraction and arrhythmias were excluded. Subjects were followed up for cardiovascular (CV) mortality and hospitalization for heart failure (HF). During follow-up for a median of 44 months (1-76), CV deaths and hospitalization for HF occurred in 41 (28%) patients. In multivariate Cox analysis, age (hazard ratio [HR], 1.07; 95% confidence interval [CI], 1.02-1.11; p = 0.001), log N-terminal pro-brain natriuretic peptide (NT-proBNP)(HR 3.81; 95% CI 1.78-8.15; p = 0.001), and left atrial volume index (HR 1.02; 95% CI 1.01-1.04; p = 0.019) were independent predictors of adverse outcomes in patients with a mid-diastolic L wave. In a stepwise model, NT-proBNP showed an incremental prognostic value for prediction of adverse outcomes when added to the clinical and echocardiographic parameters (Chi square from 30.1 to 41.1, p < 0.001). Patients with a mid-diastolic L wave and clinical, biochemical, and echocardiographic evidence of advanced diastolic dysfunction showed poor long-term clinical outcome.

  18. Role of Cell Appendages in Initial Attachment and Stability of E. coli on Silica Monitored by Nondestructive TIRF Microscopy.

    PubMed

    Wong, Kerwin K W; Olsson, Adam L J; Asadishad, Bahareh; van der Bruggen, Bart; Tufenkji, Nathalie

    2017-04-11

    Total internal reflection fluorescence (TIRF) microscopy was used to investigate initial attachment and stability of wild-type, curli-deficient (ΔcsgA), flagella-deficient (ΔflhDC), and type-1 fimbriae-deficient (Δfim) mutant E. coli strains. Suspended bacteria were injected into a flow cell where they deposited on a silica coverslip, and images were acquired over a 2 min period. TIRF microscope image analysis revealed that curli- and flagella-deficient mutants attached closer to the surface and required a longer time to find their equilibrium position (i.e., bond maturation) as compared to the wild-type and fimbriae-deficient mutants. Analysis of the change in bacterial surface area over the 2 min period also indicated that curli- and flagella-deficient mutants have less initial stability than the wild-type and fimbriae-deficient mutants, evidenced by their fluctuating position at equilibrium. TIRF observations at the microscopic level were complemented macroscopically using quartz crystal microbalance with dissipation (QCM-D) and sand-packed column experiments, which support the distinctive behavior observed at the microscopic scale. For each mutant strain, as fluorescence intensity increased in TIRF, the negative frequency shift in QCM-D (related to the attached mass of bacteria) also increased. Packed-column experiments indicated that curli- and flagella-deficient mutants exhibited a characteristically different attachment behavior and more retention as compared to the wild-type and fimbriae-deficient strains. This study utilized a new approach to understand bacterial attachment/detachment and provides new insights into the role of various appendages on initial attachment and stability.

  19. Mitochondrial sources of H2O2 generation play a key role in flow-mediated dilation in human coronary resistance arteries.

    PubMed

    Liu, Yanping; Zhao, Hongtao; Li, Hongwei; Kalyanaraman, B; Nicolosi, Alfred C; Gutterman, David D

    2003-09-19

    We previously showed that hydrogen peroxide (H2O2) contributes to flow-induced dilation in human coronary resistance arteries (HCRAs); however, the source of this H2O2 is not known. We hypothesized that the H2O2 is derived from superoxide (O2*-) generated by mitochondrial respiration. HCRAs were dissected from right atrial appendages obtained from patients during cardiac surgery and cannulated with micropipettes. H2O2-derived radicals and O2*- were detected by electron spin resonance (ESR) using BMPO as the spin trap and by histofluorescence using hydroethidine (HE, 5 micromol/L) and dichlorodihydrofluorescein (DCFH, 5 micromol/L). Diameter changes to increases in pressure gradients (20 and 100 cm H2O) were examined in the absence and the presence of rotenone (1 micromol/L), myxothiazol (100 nmol/L), cyanide (1 micromol/L), mitochondrial complex I, III, and IV inhibitors, respectively, and apocynin (3 mmol/L), a NADPH oxidase inhibitor. At a pressure gradient of 100 cm H2O, ubisemiquinone and hydroxyl radicals were detected from effluents of vessels. Including superoxide dismutase and catalase in the perfusate reduced the ESR signals. Relative ethidium and DCFH fluorescence intensities in HCRAs exposed to flow were enhanced (1.45+/-0.15 and 1.57+/-0.12, respectively compared with no-flow) and were inhibited by rotenone (0.87+/-0.17 and 0.95+/-0.07). Videomicroscopic studies showed that rotenone and myxothiazol blocked flow-induced dilation (% max. dilation at 100 cm H2O: rotenone, 74+/-3% versus 3+/-13%; myxothiazol, 67+/-3% versus 28+/-4%; P<0.05). Neither cyanide nor apocynin altered flow-induced dilation. These results suggest that shear stress induced H2O2 formation, and flow-induced dilation is derived from O2*- originating from mitochondrial respiration.

  20. Atrial Septal Defects – Clinical Manifestations, Echo Assessment, and Intervention

    PubMed Central

    Martin, Seth S; Shapiro, Edward P; Mukherjee, Monica

    2014-01-01

    Atrial septal defect (ASD) is a common congenital abnormality that occurs in the form of ostium secundum, ostium primum, sinus venosus, and rarely, coronary sinus defects. Pathophysiologic consequences of ASDs typically begin in adulthood, and include arrhythmia, paradoxical embolism, cerebral abscess, pulmonary hypertension, and right ventricular failure. Two-dimensional (2D) transthoracic echocardiography with Doppler is a central aspect of the evaluation. This noninvasive imaging modality often establishes the diagnosis and provides critical information guiding intervention. A comprehensive echocardiogram includes evaluation of anatomical ASD characteristics, flow direction, associated abnormalities (eg, anomalous pulmonary veins), right ventricular anatomy and function, pulmonary pressures, and the pulmonary/systemic flow ratio. The primary indication for ASD closure is right heart volume overload, whether symptoms are present or not. ASD closure may also be reasonable in other contexts, such as paradoxical embolism. ASD type and local clinical expertise guide choice of a percutaneous versus surgical approach to ASD closure. PMID:25861226

  1. Association of genetic variants with atrial fibrillation.

    PubMed

    Yamase, Yuichiro; Kato, Kimihiko; Horibe, Hideki; Ueyama, Chikara; Fujimaki, Tetsuo; Oguri, Mitsutoshi; Arai, Masazumi; Watanabe, Sachiro; Murohara, Toyoaki; Yamada, Yoshiji

    2016-02-01

    Recent genome-wide association studies (GWASs) identified various genes and loci that confer susceptibility to coronary artery disease or myocardial infarction among Caucasian populations. As myocardial ischemia is an important risk factor for atrial fibrillation, we hypothesized that certain polymorphisms may contribute to the genetic susceptibility to atrial fibrillation through affecting the susceptibility to coronary artery disease. The aim of the present study was to examine the possible association of atrial fibrillation in Japanese individuals with 29 polymorphisms identified as susceptibility loci for coronary artery disease or myocardial infarction in the meta-analyses of GWASs in Caucasian populations. The study subjects comprised 5,470 Japanese individuals (305 subjects with atrial fibrillation and 5,165 controls). Genotypes for 29 polymorphisms were determined by a method that combines the polymerase chain reaction and sequence-specific oligonucleotide probes with suspension array technology. Comparisons of the allele frequencies by the χ(2) test revealed that rs599839 (G→A) of the proline/serine-rich coiled-coil 1 gene (PSRC1, P=0.0084) and rs11556924 (C→T, Arg363His) of the zinc finger, C3HC-type containing 1 gene (ZC3HC1, P=0.0076) were significantly (P<0.01) associated with atrial fibrillation. Multivariable logistic regression analysis with adjustment for age, gender, body mass index, estimated glomerular filtration rate, and the prevalence of smoking, hypertension, diabetes mellitus, and dyslipidemia revealed that rs599839 (P=0.0043; odds ratio, 1.56; dominant model) and rs11556924 (P=0.0043; odds ratio, 1.93; dominant model) were significantly associated with atrial fibrillation, with the minor G and T alleles, respectively, representing risk factors for this condition. PSRC1 and ZC3HC1 may thus be susceptibility loci for atrial fibrillation in Japanese individuals.

  2. Effect of phenylephrine infusion on atrial electrophysiological properties.

    PubMed Central

    Leitch, J. W.; Basta, M.; Fletcher, P. J.

    1997-01-01

    OBJECTIVE: To determine the effect of changes in autonomic tone induced by phenylephrine infusion on atrial refractoriness and conduction. DESIGN: Left and right atrial electrophysiological properties were measured before and after a constant phenylephrine infusion designed to increase sinus cycle length by 25%. SUBJECTS: 20 patients, aged 53 (SD 6) years, undergoing electrophysiological study for investigation of idiopathic paroxysmal atrial fibrillation (seven patients) or for routine follow up after successful catheter ablation of supraventricular tachycardia (13 patients). MAIN OUTCOME MEASURES: Changes in left and right atrial effective refractory periods, atrial activation times, and frequency of induction of atrial fibrillation. RESULTS: Phenylephrine (mean dose 69 (SD 18) mg/min) increased mean blood pressure by 22 (12) mm Hg (range 7 to 44) and lengthened sinus cycle length by 223 (94) ms (20 to 430). Left atrial effective refractory period lengthened following phenylephrine infusion from 250 (25) to 264 (21) ms (P < 0.001) but there was no significant change in right atrial effective refractory period: 200 (20) v 206 (29), P = 0.11. There was a significant relation between the effect of phenylephrine on sinus cycle length and on right atrial refractoriness (r = 0.6, P = 0.005) with shortening of right atrial refractoriness in patients with the greatest prolongation in sinus cycle length. During phenylephrine infusion, the right atrial stimulus to left atrial activation time at the basic pacing cycle length of 600 ms was unchanged, at 130 (18) v 131 (17) ms, but activation delay with a premature extrastimulus increased: 212 (28) v 227 (38) ms, P = 0.002. Atrial fibrillation was induced by two of 58 refractory period measurements at baseline and by 12 of 61 measurements during phenylephrine infusion (P < 0.01). Phenylephrine increased the difference between left and right atrial refractory periods by 22.8 (19.4) ms in the five patients with induced atrial

  3. Primary neural involvement in renal haemodynamic and functional responses to prolonged stimulation of atrial receptors in anaesthetized dogs.

    PubMed

    Majid, D S; Karim, F

    1995-07-01

    To determine the precise contributory role of neural and humoral factors in the efferent mechanism of the atrial receptor-renal reflex, we have examined the effects of prolonged (45 min) stimulation of left atrial receptors on renal haemodynamics and function simultaneously in both kidneys (right kidney intact and left kidney denervated) of anaesthetized dogs. Aortic pressure in these dogs was held constant by means of an arterial reservoir connected to the aorta; heart rate changes were prevented by blocking beta 1-adrenoceptor activity with atenolol (2 mg kg-1 i.v.). Localized stimulation of atrial receptors in six dogs increased renal blood flow (6 +/- 2%), creatinine clearance (11 +/- 4%), urine flow (9 +/- 3%), sodium excretion (14 +/- 7%) and osmolal excretion (10 +/- 4%), and decreased free water clearance (14 +/- 7%) in intact kidneys, but led to no changes in denervated kidneys. In an additional four dogs, cooling the vagus nerves to 6-7 degrees C or cutting them in the neck abolished the renal responses to stimulation of atrial receptors in these stabilized preparations. These data clearly demonstrate that the renal responses to prolonged stimulation of atrial receptors are primarily mediated via myelinated vagal afferents and renal sympathetic efferents.

  4. A Conserved MicroRNA Regulatory Circuit Is Differentially Controlled during Limb/Appendage Regeneration

    PubMed Central

    King, Benjamin L.; Yin, Viravuth P.

    2016-01-01

    Background Although regenerative capacity is evident throughout the animal kingdom, it is not equally distributed throughout evolution. For instance, complex limb/appendage regeneration is muted in mammals but enhanced in amphibians and teleosts. The defining characteristic of limb/appendage regenerative systems is the formation of a dedifferentiated tissue, termed blastema, which serves as the progenitor reservoir for regenerating tissues. In order to identify a genetic signature that accompanies blastema formation, we employ next-generation sequencing to identify shared, differentially regulated mRNAs and noncoding RNAs in three different, highly regenerative animal systems: zebrafish caudal fins, bichir pectoral fins and axolotl forelimbs. Results These studies identified a core group of 5 microRNAs (miRNAs) that were commonly upregulated and 5 miRNAs that were commonly downregulated, as well as 4 novel tRNAs fragments with sequences conserved with humans. To understand the potential function of these miRNAs, we built a network of 1,550 commonly differentially expressed mRNAs that had functional relationships to 11 orthologous blastema-associated genes. As miR-21 was the most highly upregulated and most highly expressed miRNA in all three models, we validated the expression of known target genes, including the tumor suppressor, pdcd4, and TGFβ receptor subunit, tgfbr2 and novel putative target genes such as the anti-apoptotic factor, bcl2l13, Choline kinase alpha, chka and the regulator of G-protein signaling, rgs5. Conclusions Our extensive analysis of RNA-seq transcriptome profiling studies in three regenerative animal models, that diverged in evolution ~420 million years ago, reveals a common miRNA-regulated genetic network of blastema genes. These comparative studies extend our current understanding of limb/appendage regeneration by identifying previously unassociated blastema genes and the extensive regulation by miRNAs, which could serve as a foundation

  5. Development of segments and appendages in embryos of the desert scorpion Paruroctonus mesaensis (Scorpiones: Vaejovidae).

    PubMed

    Farley, R D

    2001-10-01

    The scanning electron microscope was used to study the changing features of scorpion embryos from the blastula through early stages in the development of appendages. The earliest scorpion fossils (Silurian period) have structures more advanced than the embryos herein, so the possibility is considered that these embryos still retain and display some features indicative of evolutionary patterns in adult pre-Silurian ancestors. The blastodisc stage is followed by a knob-like germinal center that gives rise to most of the embryo body. The germinal center elongates on the ventral surface of the spherical yolk mass. The broad cephalic lobe is first delineated from the following pedipalpal segment. The limbbuds for the pedipalps and anterior walking legs appear, as additional segments are added at a growth zone at the rear of the embryo body. Initially, in the cephalic lobe there are no limbbuds; then the cheliceral buds emerge from the posterior part of the lobe. The stomodeum appears first in the anterior half of the cephalic lobe, but an oral groove forms and the mouth is displaced posteriorly within the groove. This repositioning allows space anteriorly for invagination (semilunar grooves) of epithelium for the brain and medial eyes. The mouth is directed ventrally in all stages of this study. The widespread chelicerae are initially posterior to the mouth, but later move anterior and dorsal to it. Small limbbud bulges on mesosomal segments disappear later and never become protruding appendages. Metasomal segments are produced free from the yolk surface in a ventral flexure beneath the embryo body. The telson starts as two spherical lobes, but later elongates and tapers distally, not yet developing the sharp sting (aculeus) seen in Silurian and all subsequent scorpions. The walking legs are digitigrade, as in most fossil aquatic scorpions. Segments are delineated in the appendages; the chelicerae and pedipalps are divided distally for chela (claw) formation. Bilateral

  6. Mitophagy and mitochondrial biogenesis in atrial tissue of patients undergoing heart surgery with cardiopulmonary bypass

    PubMed Central

    Andres, Allen M.; Tucker, Kyle C.; Thomas, Amandine; Taylor, David J.R.; Jahania, Salik M.; Dabir, Reza; Pourpirali, Somayeh; Brown, Jamelle A.; Westbrook, David G.; Ballinger, Scott W.; Mentzer, Robert M.

    2017-01-01

    Mitophagy occurs during ischemia/reperfusion (I/R) and limits oxidative stress and injury. Mitochondrial turnover was assessed in patients undergoing cardiac surgery involving cardiopulmonary bypass (CPB). Paired biopsies of right atrial appendage before initiation and after weaning from CPB were processed for protein analysis, mitochondrial DNA/nuclear DNA ratio (mtDNA:nucDNA ratio), mtDNA damage, mRNA, and polysome profiling. Mitophagy in the post-CPB samples was evidenced by decreased levels of mitophagy adapters NDP52 and optineurin in whole tissue lysate, decreased Opa1 long form, and translocation of Parkin to the mitochondrial fraction. PCR analysis of mtDNA comparing amplification of short vs. long segments of mtDNA revealed increased damage following cardiac surgery. Surprisingly, a marked increase in several mitochondria-specific protein markers and mtDNA:nucDNA ratio was observed, consistent with increased mitochondrial biogenesis. mRNA analysis suggested that mitochondrial biogenesis was traniscription independent and likely driven by increased translation of existing mRNAs. These findings demonstrate in humans that both mitophagy and mitochondrial biogenesis occur during cardiac surgery involving CPB. We suggest that mitophagy is balanced by mitochondrial biogenesis during I/R stress experienced during surgery. Mitigating mtDNA damage and elucidating mechanisms regulating mitochondrial turnover will lead to interventions to improve outcome after I/R in the setting of heart disease. PMID:28239650

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

    PubMed

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

    2015-01-01

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

  8. [Atrial defibrillators or implantable atrioverters. Initial results].

    PubMed

    Lévy, S; Taramasco, V; Corbelli, J L; Mistretta, R; Dolla, E; Ricard, P

    1998-07-01

    The atrial defibrillator is a new non-pharmacological treatment of atrial fibrillation (AF) for restoration of sinus rhythm. This device has two programmable modes: automatic or activated by the physician or patient. In the automatic mode, the device delivers a shock synchronous with the R wave to restore sinus rhythm when AF is detected. Two patients with paroxysmal AF resistant to pharmacological therapy were included in a study to assess the efficacy and safety of the atrial defibrillator in the mode activated by the physician. The device implanted in the pectoral region is connected to 3 electrodes, two for atrial defibrillation and sensing positioned in the coronary sinus and right atrium respectively and a sensing and pacing electrode in the right ventricle. The right ventricle is paced if a post-shock pause is detected. It is possible to interrogate the device with a programmer using its Holter function and so determine the number of episodes of AF sensed and treated. The number, intensity and energy of the shocks and the parameters of ventricular stimulation are programmable. In these two patients, the atrial defibrillator effectively reduced prolonged episodes of AF with a follow-up of 12 and 7 months. No pro-arrhythmic effects were observed. Further clinical evaluation is under way to assess this new mode of treatment, including the mode activated by the patient, safety and tolerance of the shocks. In our two patients, the treatment of prolonged episodes of AF was followed by reduction of many short or asymptomatic episodes.

  9. Aorta-Right Atrial Tunnel

    PubMed Central

    Krishna, Cheemalapati Sai; Baruah, Dibya Kumar; Reddy, Gangireddy Venkateswara; Panigrahi, Nanda Kishore; Suman, Kalagara; Kumar, Palli Venkata Naresh

    2010-01-01

    Aorta–right atrial tunnel is a vascular channel that originates from one of the sinuses of Valsalva and terminates in either the superior vena cava or the right atrium. The tunnel is classified as anterior or posterior, depending upon its course in relation to the ascending aorta. An origin above the sinotubular ridge differentiates the tunnel from an aneurysm of the sinus of Valsalva, and the absence of myocardial branches differentiates it from a coronary–cameral fistula. Clinical presentation ranges from an asymptomatic precordial murmur to congestive heart failure. The embryologic background and pathogenesis of this lesion are attributable either to an aneurysmal dilation of the sinus nodal artery or to a congenital weakness of the aortic media. In either circumstance, progressive enlargement of the tunnel and ultimate rupture into the low-pressure right atrium could occur under the influence of the systemic pressure. The lesion is diagnosed by use of 2-dimensional echocardiography and cardiac catheterization. Computed tomographic angiography is an additional noninvasive diagnostic tool. The possibility of complications necessitates early therapy, even in asymptomatic patients or those with a hemodynamically insignificant shunt. Available treatments are catheter-based intervention, external ligation under controlled hypotension, or surgical closure with the patient under cardiopulmonary bypass. Herein, we discuss the cases of 2 patients who had this unusual anomaly. We highlight the outcome on follow-up imaging (patient 1) and the identification and safe reimplantation of the coronary artery (patient 2). PMID:20844628

  10. [Antithrombotic therapy in atrial arrhythmia].

    PubMed

    Cohen, Ariel

    2004-02-15

    The principal complication of the atrial arrythmias is the thrombo-embolic accident, notably the cerebro-vascular accident. The efficacity of the oral anticoagulants in reducing cerebro-vascular accidents has been demonstrated in numerous studies. This is significantly superior to that obtained with the anti-platelet drugs. However, the anti-vitamin K drugs (warfarin) carry a risk of serious haemorrhage of around 5% per year. This restricts the proposal of this treatment to patients with an elevated risk of vascular accidents: age, diabetes, previous cerebro-vascular accidents, and cardiac failure are the risk factors. Nevertheless, the risk of haemorrhage is responsible for an under prescription of the anticoagulants in the elderly. This explains the interest aroused by alternative therapeutics: the results of trials on ximelagatran, a direct anti-thrombin, are promising. In patients with an arrythmia, cardioversion carries a thrombo-embolic risk of around 1%. This risk is reduced by prior anticoagulant treatment. The procedure for this treatment is orientated by a trans-oesophageal echocardiogram. The incertitude of the duration of anticoagulant therapy without cardioversion calls for respect of the arrythmia. The treatment of this is limited to control of the cardiac rhythm and anticoagulant treatment.

  11. Aorta-right atrial tunnel.

    PubMed

    Sai Krishna, Cheemalapati; Baruah, Dibya Kumar; Reddy, Gangireddy Venkateswara; Panigrahi, Nanda Kishore; Suman, Kalagara; Kumar, Palli Venkata Naresh

    2010-01-01

    Aorta-right atrial tunnel is a vascular channel that originates from one of the sinuses of Valsalva and terminates in either the superior vena cava or the right atrium. The tunnel is classified as anterior or posterior, depending upon its course in relation to the ascending aorta. An origin above the sinotubular ridge differentiates the tunnel from an aneurysm of the sinus of Valsalva, and the absence of myocardial branches differentiates it from a coronary-cameral fistula. Clinical presentation ranges from an asymptomatic precordial murmur to congestive heart failure. The embryologic background and pathogenesis of this lesion are attributable either to an aneurysmal dilation of the sinus nodal artery or to a congenital weakness of the aortic media. In either circumstance, progressive enlargement of the tunnel and ultimate rupture into the low-pressure right atrium could occur under the influence of the systemic pressure.The lesion is diagnosed by use of 2-dimensional echocardiography and cardiac catheterization. Computed tomographic angiography is an additional noninvasive diagnostic tool. The possibility of complications necessitates early therapy, even in asymptomatic patients or those with a hemodynamically insignificant shunt. Available treatments are catheter-based intervention, external ligation under controlled hypotension, or surgical closure with the patient under cardiopulmonary bypass.Herein, we discuss the cases of 2 patients who had this unusual anomaly. We highlight the outcome on follow-up imaging (patient 1) and the identification and safe reimplantation of the coronary artery (patient 2).

  12. Cardiovascular Disease Update: Atrial Fibrillation.

    PubMed

    McDivitt, Johnathan D; Barstow, Craig

    2017-03-01

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. The prevalence increases with age, especially in the seventh and eighth decades of life. AF also is associated with multiple risk factors and conditions that are managed commonly in family medicine settings, such as hypertension and diabetes. Rhythm control and rate control are primarily equivalent for mortality rate, but patients treated for rhythm control have more hospitalizations; however, rhythm control may be a viable option for select patients. Beta blockers and nondihydropyridine calcium channel blockers can be used to achieve rate control. Pharmacotherapy or electrical cardioversion can be used to achieve rhythm control, and antiarrhythmic drugs are used to maintain sinus rhythm. Catheter ablation is an option for symptomatic patients whose AF is refractory to standard treatment. The CHA2DS2-VASc score should be used to predict the risk of stroke for patients with AF. Patients with nonvalvular AF and a history of stroke or transient ischemic attack or CHA2DS2-VASc scores of 2 or greater should be treated with warfarin or novel oral anticoagulants. Patients with valvular AF should be treated with warfarin.

  13. Three-dimensionally preserved minute larva of a great-appendage arthropod from the early Cambrian Chengjiang biota

    PubMed Central

    Liu, Yu; Melzer, Roland R.; Haug, Joachim T.; Haug, Carolin; Briggs, Derek E. G.; Hörnig, Marie K.; He, Yu-yang; Hou, Xian-guang

    2016-01-01

    A three-dimensionally preserved 2-mm-long larva of the arthropod Leanchoilia illecebrosa from the 520-million-year-old early Cambrian Chengjiang biota of China represents the first evidence, to our knowledge, of such an early developmental stage in a short-great-appendage (SGA) arthropod. The larva possesses a pair of three-fingered great appendages, a hypostome, and four pairs of well-developed biramous appendages. More posteriorly, a series of rudimentary limb Anlagen revealed by X-ray microcomputed tomography shows a gradient of decreasing differentiation toward the rear. This, and postembryonic segment addition at the putative growth zone, are features of late-stage metanauplii of eucrustaceans. L. illecebrosa and other SGA arthropods, however, are considered representative of early chelicerates or part of the stem lineage of all euarthropods. The larva of an early Cambrian SGA arthropod with a small number of anterior segments and their respective appendages suggests that posthatching segment addition occurred in the ancestor of Euarthropoda. PMID:27140601

  14. Three-dimensionally preserved minute larva of a great-appendage arthropod from the early Cambrian Chengjiang biota

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Melzer, Roland R.; Haug, Joachim T.; Haug, Carolin; Briggs, Derek E. G.; Hörnig, Marie K.; He, Yu-yang; Hou, Xian-guang

    2016-05-01

    A three-dimensionally preserved 2-mm-long larva of the arthropod Leanchoilia illecebrosa from the 520-million-year-old early Cambrian Chengjiang biota of China represents the first evidence, to our knowledge, of such an early developmental stage in a short-great-appendage (SGA) arthropod. The larva possesses a pair of three-fingered great appendages, a hypostome, and four pairs of well-developed biramous appendages. More posteriorly, a series of rudimentary limb Anlagen revealed by X-ray microcomputed tomography shows a gradient of decreasing differentiation toward the rear. This, and postembryonic segment addition at the putative growth zone, are features of late-stage metanauplii of eucrustaceans. L. illecebrosa and other SGA arthropods, however, are considered representative of early chelicerates or part of the stem lineage of all euarthropods. The larva of an early Cambrian SGA arthropod with a small number of anterior segments and their respective appendages suggests that posthatching segment addition occurred in the ancestor of Euarthropoda.

  15. Three-dimensionally preserved minute larva of a great-appendage arthropod from the early Cambrian Chengjiang biota.

    PubMed

    Liu, Yu; Melzer, Roland R; Haug, Joachim T; Haug, Carolin; Briggs, Derek E G; Hörnig, Marie K; He, Yu-Yang; Hou, Xian-Guang

    2016-05-17

    A three-dimensionally preserved 2-mm-long larva of the arthropod Leanchoilia illecebrosa from the 520-million-year-old early Cambrian Chengjiang biota of China represents the first evidence, to our knowledge, of such an early developmental stage in a short-great-appendage (SGA) arthropod. The larva possesses a pair of three-fingered great appendages, a hypostome, and four pairs of well-developed biramous appendages. More posteriorly, a series of rudimentary limb Anlagen revealed by X-ray microcomputed tomography shows a gradient of decreasing differentiation toward the rear. This, and postembryonic segment addition at the putative growth zone, are features of late-stage metanauplii of eucrustaceans. L. illecebrosa and other SGA arthropods, however, are considered representative of early chelicerates or part of the stem lineage of all euarthropods. The larva of an early Cambrian SGA arthropod with a small number of anterior segments and their respective appendages suggests that posthatching segment addition occurred in the ancestor of Euarthropoda.

  16. Cad74A is regulated by BR and is required for robust dorsal appendage formation in Drosophila oogenesis

    PubMed Central

    Zartman, Jeremiah J.; Yakoby, Nir; Bristow, Chris A.; Zhou, Xiaofeng; Schlichting, Karin; Dahmann, Christian; Shvartsman, Stanislav Y.

    2008-01-01

    Drosophila egg development is an established model for studying epithelial patterning and morphogenesis, but the connection between signaling pathways and egg morphology is still incompletely understood. We have identified a non-classical cadherin, Cad74A, as a putative adhesion gene that bridges epithelial patterning and morphogenesis in the follicle cells. Starting in mid-oogenesis, Cad74A is expressed in the follicle cells that contact the oocyte, including the border cells and most of the columnar follicle cells. However, Cad74A is repressed in two dorsolateral patches of follicle cells, which participate in the formation of tubular respiratory appendages. We show genetically that Cad74A is downstream of the EGFR and BMP signaling pathways and is repressed by the Zn-finger transcription factor Broad. The correlation of Cad74A repression in the cells that bend out of the plane of the follicular epithelium is preserved across Drosophila species and mutant backgrounds exhibiting a range of eggshell phenotypes. Complete removal of Cad74A from the follicle cells causes defects in dorsal appendage formation. Ectopic expression of Cad74A in the roof cells results in shortened, flattened appendages due to the hindered migration of the roof cells. Based on these results, we propose that Cad74A is part of the adhesive machinery that enables robust dorsal appendage formation, and as such provides a link between the patterning of the follicle cells and eggshell morphogenesis. PMID:18708045

  17. The chemosensory appendage proteome of Amblyomma americanum (Acari: Ixodidae) reveals putative odorant-binding and other chemoreception-related proteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Proteomic analyses were done on 2 chemosensory appendages of the lone star tick, Amblyomma americanum. Proteins in the fore tarsi, which contain the olfactory Haller's organ, and in the palps, that include gustatory sensilla, were compared with proteins in the third tarsi. Also, male and female tick...

  18. Gross distortion of atrioventricular and ventriculo-arterial relations associated with left juxtaposition of atrial appendages. Bizarre form of atrioventricular criss-cross.

    PubMed Central

    Coto, E O; Wilkinson, J L; Dickinson, D F; Rufilanchas, J J; Márquez, J

    1979-01-01

    Two pathological specimens are described in which a bizarre distortion of atrioventricular and ventriculoarterial relations existed. In both cases anterior and leftward displacement of the tricuspid valve coexisted with rightward displacement of the infundibular regions and semilunar valves. Abnormal expansion of the AV canal, possibly secondary to malrotation of the cardiac tube, is considered as a possible cause of the anomaly. One of the hearts showed severe subpulmonary stenosis produced by a valve-like structure which was well differentiated, with a complete annulus and chordae tendineae that inserted in a parachute-like fashion on the infundibular septum. The morphology of this structure was clearly different from that fo the fibrous tags described in other anomalies. Its origin is uncertain. These anomalies have important implications in relation to the nomenclature and classification of congenital heart malformations, and illustrate the value of recent modifications of the segmental approach. Images PMID:465217

  19. Peripheral vasodilatation determines cardiac output in exercising humans: insight from atrial pacing.

    PubMed

    Bada, A A; Svendsen, J H; Secher, N H; Saltin, B; Mortensen, S P

    2012-04-15

    In dogs, manipulation of heart rate has no effect on the exercise-induced increase in cardiac output. Whether these findings apply to humans remain uncertain, because of the large differences in cardiovascular anatomy and regulation. To investigate the role of heart rate and peripheral vasodilatation in the regulation of cardiac output during steady-state exercise, we measured central and peripheral haemodynamics in 10 healthy male subjects, with and without atrial pacing (100–150 beats min(−1)) during: (i) resting conditions, (ii) one-legged knee extensor exercise (24 W) and (iii) femoral arterial ATP infusion at rest. Exercise and ATP infusion increased cardiac output, leg blood flow and vascular conductance (P < 0.05), whereas cerebral perfusion remained unchanged. During atrial pacing increasing heart rate by up to 54 beats min(−1), cardiac output did not change in any of the three conditions, because of a parallel decrease in stroke volume (P < 0.01). Atrial pacing increased mean arterial pressure (MAP) at rest and during ATP infusion (P < 0.05), whereas MAP remained unchanged during exercise. Atrial pacing lowered central venous pressure (P < 0.05) and pulmonary capillary wedge pressure (P < 0.05) in all conditions, whereas it did not affect pulmonary mean arterial pressure. Atrial pacing lowered the left ventricular contractility index (dP/dt) (P < 0.05) in all conditions and plasma noradrenaline levels at rest (P < 0.05), but not during exercise and ATP infusion. These results demonstrate that the elevated cardiac output during steady-state exercise is regulated by the increase in skeletal muscle blood flow and venous return to the heart, whereas the increase in heart rate appears to be secondary to the regulation of cardiac output.

  20. Pharmacologic Atrial Natriuretic Peptide Reduces Human Leg Capillary Filtration

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  1. Pharmacologic Atrial Natriuretic Peptide Reduces Human Leg Capillary Filtration

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  2. The dynamics of spin stabilized spacecraft with movable appendages, part 2

    NASA Technical Reports Server (NTRS)

    Bainum, P. M.

    1976-01-01

    The dynamics and stability of a spin stabilized spacecraft with a hinged appendage system are treated analytically and numerically. The hinged system consists of a central hub with masses attached to (assumed) massless booms of fixed length whose orientation relative to the main part can change. The general three dimensional deployment dynamics of such a hinged system is considered without any restriction on the location of the hinge points. The equations of motion for the hinged system, with viscous damping at both hinge points, are linearized about the nominal equilibrium position where the booms are orthogonal to the nominal spin axis for the case of two dimensional and three dimensional motion. Analytic stability criteria are obtained from the necessary condition on the sign of all the coefficients in the system characteristic equation.

  3. Optimal control/structure integrated design of a flexible space platform with articulated appendages

    NASA Technical Reports Server (NTRS)

    Kelkar, Atul G.; Alberts, Thomas E.

    1991-01-01

    A complete set of closed form symbolic equations are developed for a 2-D model of a system comprised of a flexible platform with articulated appendages. The system considered has a flexible two link manipulator, with joint compliance, at one end of the flexible platform and an articulated antenna on the other end. The model is formulated using a Lagrangian approach which incorporates homogeneous transformation matrices, similar to those typically seen in the robotics literature, for the kinematic representation. The integrated control/structure design strategy considered emphasizes rapid system response and minimal structural weight. Constraints are included to keep antenna pointing error to a minimum, and at the same time achieve accurate end point positioning of the manipulator with minimal oscillations.

  4. A shared role for sonic hedgehog signalling in patterning chondrichthyan gill arch appendages and tetrapod limbs.

    PubMed

    Gillis, J Andrew; Hall, Brian K

    2016-04-15

    Chondrichthyans (sharks, skates, rays and holocephalans) possess paired appendages that project laterally from their gill arches, known as branchial rays. This led Carl Gegenbaur to propose that paired fins (and hence tetrapod limbs) originally evolved via transformation of gill arches. Tetrapod limbs are patterned by asonic hedgehog(Shh)-expressing signalling centre known as the zone of polarising activity, which establishes the anteroposterior axis of the limb bud and maintains proliferative expansion of limb endoskeletal progenitors. Here, we use loss-of-function, label-retention and fate-mapping approaches in the little skate to demonstrate that Shh secretion from a signalling centre in the developing gill arches establishes gill arch anteroposterior polarity and maintains the proliferative expansion of branchial ray endoskeletal progenitor cells. These findings highlight striking parallels in the axial patterning mechanisms employed by chondrichthyan branchial rays and paired fins/limbs, and provide mechanistic insight into the anatomical foundation of Gegenbaur's gill arch hypothesis.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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. Analysis of left atrial respiratory and cardiac motion for cardiac ablation therapy

    NASA Astrophysics Data System (ADS)

    Rettmann, M. E.; Holmes, D. R.; Johnson, S. B.; Lehmann, H. I.; Robb, R. A.; Packer, D. L.

    2015-03-01

    Cardiac ablation therapy is often guided by models built from preoperative computed tomography (CT) or magnetic resonance imaging (MRI) scans. One of the challenges in guiding a procedure from a preoperative model is properly synching the preoperative models with cardiac and respiratory motion through computational motion models. In this paper, we describe a methodology for evaluating cardiac and respiratory motion in the left atrium and pulmonary veins of a beating canine heart. Cardiac catheters were used to place metal clips within and near the pulmonary veins and left atrial appendage under fluoroscopic and ultrasound guidance and a contrast-enhanced, 64-slice multidetector CT scan was collected with the clips in place. Each clip was segmented from the CT scan at each of the five phases of the cardiac cycle at both end-inspiration and end-expiration. The centroid of each segmented clip was computed and used to evaluate both cardiac and respiratory motion of the left atrium. A total of three canine studies were completed, with 4 clips analyzed in the first study, 5 clips in the second study, and 2 clips in the third study. Mean respiratory displacement was 0.2+/-1.8 mm in the medial/lateral direction, 4.7+/-4.4 mm in the anterior/posterior direction (moving anterior on inspiration), and 9.0+/-5.0 mm superior/inferior (moving inferior with inspiration). At end inspiration, the mean left atrial cardiac motion at the clip locations was 1.5+/-1.3 mm in the medial/lateral direction, and 2.1+/-2.0 mm in the anterior/posterior and 1.3+/-1.2 mm superior/inferior directions. At end expiration, the mean left atrial cardiac motion at the clip locations was 2.0+/-1.5mm in the medial/lateral direction, 3.0+/-1.8mm in the anterior/posterior direction, and 1.5+/-1.5 mm in the superior/inferior directions.

  7. In vitro percutaneous absorption in mouse skin: influence of skin appendages

    SciTech Connect

    Kao, J.; Hall, J.; Helman, G.

    1988-06-15

    Skin appendages are often envisaged as channels that bypass the stratum corneum barrier and are generally thought to facilitate the dermal absorption of topical agents. However, the significance of this transappendageal pathway in percutaneous absorption remains to be assessed experimentally. With the use of a skin organ culture penetration chamber system, the influence of skin appendages on the in vitro permeation of topically applied benzo(a)pyrene and testosterone (5 micrograms/2 cm2) was examined in skin preparations from both haired and hairless mice. Haired mice examined included the C57BL6, C3H, DBA2, Balbc, and Sencar strains and the hairless mice were the HRS and SKH. In all mouse strains examined, the overall permeation of testosterone (greater than 65% of applied dose) 16 hr following in vitro topical application was greater than that of benzo(a)pyrene (less than 10%). No strain differences were observed with respect to the percutaneous permeation of testosterone; however, percutaneous permeation of benzo(a)pyrene in the haired mice (7-10% of applied dose) was higher than that in the hairless mice (2%). In an in-house derived mouse strain which showed three phenotypic variants due to hair densities, the permeability to both compounds was highest in the skin of the haired phenotype (testosterone 67%, benzo(a)pyrene 7%), lowest in the hairless phenotype (35 and 1%, respectively) and intermediate in the fuzzy-haired animal (57 and 3%, respectively). Examination by fluorescence microscopy of cryosections of skin, prepared 1 hr after topical benzo(a)pyrene, showed areas of intense fluorescence deep within the nonfluorescing dermis of skin from the haired phenotype. These fluorescent areas were correlated with follicular ducts and sebaceous glands.

  8. A Sexually Dimorphic Corolla Appendage Affects Pollen Removal and Floral Longevity in Gynodioecious Cyananthus delavayi (Campanulaceae)

    PubMed Central

    Niu, Yang; Zhang, Zhi-Qiang; Liu, Chang-Qiu; Li, Zhi-Min; Sun, Hang

    2015-01-01

    The floral traits of bisexual flowers may evolve in response to selection on both male and female functions, but the relative importance of selection associated with each of these two aspects is poorly resolved. Sexually dimorphic traits in plants with unisexual flowers may reflect gender-specific selection, providing opportunities for gaining an increased understanding of the evolution of specific floral traits. We examined sexually dimorphic patterns of floral traits in perfect and female flowers of the gynodioecious species Cyananthus delavayi. A special corolla appendage, the throat hair, was investigated experimentally to examine its influences on male and female function. We found that perfect flowers have larger corollas and much longer throat hairs than female flowers, while female ones have much exerted stigmas. The presence of throat hairs prolonged the duration of pollen presentation by restricting the amount of pollen removed by pollen-collecting bees during each visit. Floral longevity was negatively related to the rate of pollen removal. When pollen removal rate was limited in perfect flowers, the duration of the female phases diminished with the increased male phase duration. There was a weak negative correlation between throat hair length and seed number per fruit in female flowers, but this correlation was not significant in perfect flowers. These results suggest that throat hairs may enhance male function in terms of prolonged pollen presentation. However, throat hairs have no obvious effect on female function in terms of seed number per fruit. The marked sexual dimorphism of this corolla appendage in C. delavayi is likely to have evolved and been maintained by gender-specific selection. PMID:25603479

  9. Peripheral Axons of the Adult Zebrafish Maxillary Barbel Extensively Remyelinate During Sensory Appendage Regeneration

    PubMed Central

    Moore, Alex C.; Mark, Tiffany E.; Hogan, Ann K.; Topczewski, Jacek; LeClair, Elizabeth E.

    2013-01-01

    Myelination is a cellular adaptation allowing rapid conduction along axons. We have investigated peripheral axons of the zebrafish maxillary barbel (ZMB), an optically clear sensory appendage. Each barbel carries taste buds, solitary chemosensory cells, and epithelial nerve endings, all of which regenerate after amputation (LeClair and Topczewski [2010] PLoS One 5:e8737). The ZMB contains axons from the facial nerve; however, myelination within the barbel itself has not been established. Transcripts of myelin basic protein (mbp) are expressed in normal and regenerating adult barbels, indicating activity in both maintenance and repair. Myelin was confirmed in situ by using toluidine blue, an anti-MBP antibody, and transmission electron microscopy (TEM). The adult ZMB contains ~180 small-diameter axons (<2 μm), approximately 60% of which are myelinated. Developmental myelination was observed via whole-mount immunohistochemistry 4-6 weeks postfertilization, showing myelin sheaths lagging behind growing axons. Early-regenerating axons (10 days postsurgery), having no or few myelin layers, were disorganized within a fibroblast-rich collagenous scar. Twenty-eight days postsurgery, barbel axons had grown out several millimeters and were organized with compact myelin sheaths. Fiber types and axon areas were similar between normal and regenerated tissue; within 4 weeks, regenerating axons restored ~85% of normal myelin thickness. Regenerating barbels express multiple promyelinating transcription factors (sox10, oct6 = pou3f1; krox20a/b = egr2a/b) typical of Schwann cells. These observations extend our understanding of the zebrafish peripheral nervous system within a little-studied sensory appendage. The accessible ZMB provides a novel context for studying axon regeneration, Schwann cell migration, and remyelination in a model vertebrate. PMID:22592645

  10. On dorsal prothoracic appendages in treehoppers (Hemiptera: Membracidae) and the nature of morphological evidence.

    PubMed

    Mikó, István; Friedrich, Frank; Yoder, Matthew J; Hines, Heather M; Deitz, Lewis L; Bertone, Matthew A; Seltmann, Katja C; Wallace, Matthew S; Deans, Andrew R

    2012-01-01

    A spectacular hypothesis was published recently, which suggested that the "helmet" (a dorsal thoracic sclerite that obscures most of the body) of treehoppers (Insecta: Hemiptera: Membracidae) is connected to the 1st thoracic segment (T1; prothorax) via a jointed articulation and therefore was a true appendage. Furthermore, the "helmet" was interpreted to share multiple characteristics with wings, which in extant pterygote insects are present only on the 2nd (T2) and 3rd (T3) thoracic segments. In this context, the "helmet" could be considered an evolutionary novelty. Although multiple lines of morphological evidence putatively supported the "helmet"-wing homology, the relationship of the "helmet" to other thoracic sclerites and muscles remained unclear. Our observations of exemplar thoraces of 10 hemipteran families reveal multiple misinterpretations relevant to the "helmet"-wing homology hypothesis as originally conceived: 1) the "helmet" actually represents T1 (excluding the fore legs); 2) the "T1 tergum" is actually the anterior dorsal area of T2; 3) the putative articulation between the "helmet" and T1 is actually the articulation between T1 and T2. We conclude that there is no dorsal, articulated appendage on the membracid T1. Although the posterior, flattened, cuticular evagination (PFE) of the membracid T1 does share structural and genetic attributes with wings, the PFE is actually widely distributed across Hemiptera. Hence, the presence of this structure in Membracidae is not an evolutionary novelty for this clade. We discuss this new interpretation of the membracid T1 and the challenges of interpreting and representing morphological data more broadly. We acknowledge that the lack of data standards for morphology is a contributing factor to misinterpreted results and offer an example for how one can reduce ambiguity in morphology by referencing anatomical concepts in published ontologies.

  11. On Dorsal Prothoracic Appendages in Treehoppers (Hemiptera: Membracidae) and the Nature of Morphological Evidence

    PubMed Central

    Mikó, István; Friedrich, Frank; Yoder, Matthew J.; Hines, Heather M.; Deitz, Lewis L.; Bertone, Matthew A.; Seltmann, Katja C.; Wallace, Matthew S.; Deans, Andrew R.

    2012-01-01

    A spectacular hypothesis was published recently, which suggested that the “helmet” (a dorsal thoracic sclerite that obscures most of the body) of treehoppers (Insecta: Hemiptera: Membracidae) is connected to the 1st thoracic segment (T1; prothorax) via a jointed articulation and therefore was a true appendage. Furthermore, the “helmet” was interpreted to share multiple characteristics with wings, which in extant pterygote insects are present only on the 2nd (T2) and 3rd (T3) thoracic segments. In this context, the “helmet” could be considered an evolutionary novelty. Although multiple lines of morphological evidence putatively supported the “helmet”-wing homology, the relationship of the “helmet” to other thoracic sclerites and muscles remained unclear. Our observations of exemplar thoraces of 10 hemipteran families reveal multiple misinterpretations relevant to the “helmet”-wing homology hypothesis as originally conceived: 1) the “helmet” actually represents T1 (excluding the fore legs); 2) the “T1 tergum” is actually the anterior dorsal area of T2; 3) the putative articulation between the “helmet” and T1 is actually the articulation between T1 and T2. We conclude that there is no dorsal, articulated appendage on the membracid T1. Although the posterior, flattened, cuticular evagination (PFE) of the membracid T1 does share structural and genetic attributes with wings, the PFE is actually widely distributed across Hemiptera. Hence, the presence of this structure in Membracidae is not an evolutionary novelty for this clade. We discuss this new interpretation of the membracid T1 and the challenges of interpreting and representing morphological data more broadly. We acknowledge that the lack of data standards for morphology is a contributing factor to misinterpreted results and offer an example for how one can reduce ambiguity in morphology by referencing anatomical concepts in published ontologies. PMID:22272287

  12. Nitric Oxide Synthases and Atrial Fibrillation

    PubMed Central

    Bonilla, Ingrid M.; Sridhar, Arun; Györke, Sandor; Cardounel, Arturo J.; Carnes, Cynthia A.

    2012-01-01

    Oxidative stress has been implicated in the pathogenesis of atrial fibrillation. There are multiple systems in the myocardium which contribute to redox homeostasis, and loss of homeostasis can result in oxidative stress. Potential sources of oxidants include nitric oxide synthases (NOS), which normally produce nitric oxide in the heart. Two NOS isoforms (1 and 3) are normally expressed in the heart. During pathologies such as heart failure, there is induction of NOS 2 in multiple cell types in the myocardium. In certain conditions, the NOS enzymes may become uncoupled, shifting from production of nitric oxide to superoxide anion, a potent free radical and oxidant. Multiple lines of evidence suggest a role for NOS in the pathogenesis of atrial fibrillation. Therapeutic approaches to reduce atrial fibrillation by modulation of NOS activity may be beneficial, although further investigation of this strategy is needed. PMID:22536189

  13. Practice implications of the Atrial Fibrillation Guidelines.

    PubMed

    Curtis, Anne B

    2013-06-01

    Atrial fibrillation is one of the most common and complex cardiac arrhythmias. Using currently available evidence, leading medical societies have established recommendations for the optimal management of atrial fibrillation. These guidelines have recently been updated by 4 consensus groups: the European Society of Cardiology, the American College of Chest Physicians, the Canadian Cardiovascular Society, and a task force of 3 societies from the United States: the American College of Cardiology Foundation, the American Heart Association, and the Heart Rhythm Society. The present review focused on the similarities and differences among these recently updated guidelines. Key revisions included updated information on newer treatments for rhythm control, treatment options to reduce atrial fibrillation complications, and updated anticoagulant management for thromboprophylaxis.

  14. [Operative management of trigono-atrial lesions].

    PubMed

    Hussein, S

    1998-01-01

    Trigono-atrial-Lesions are microsurgically serios accessible, the results of transcortical aproaches are difficult and frequently unsatisfactory. The microsurgical anatomy of the trigono-atrial region will be studied on 100 brain hemispheres (the posterior cerebral arteries were injected selective on 70 hemispheres). According to the anatomical findings, an interhemispheric microsurgical approach has been developed. The operative results of 25 patients with different atrial lesions are presented. There was no operative mortality, the postoperative morbidity was 12%, in 24% (n = 6) the preoperative state was still unchanged, in 12 cases (48%) we note a normal neurological and neuropsychological postoperative status. In 4 patients (16%) the neurological symptoms are postoperatively improved. According to these first results, the described transatrial approach seems to be a real alternative for careful selected meanly leftsided lesions of the trigone.

  15. Functional dissection of an AP-2 beta2 appendage-binding sequence within the autosomal recessive hypercholesterolemia protein.

    PubMed

    Mishra, Sanjay K; Keyel, Peter A; Edeling, Melissa A; Dupin, Amie L; Owen, David J; Traub, Linton M

    2005-05-13

    The autosomal recessive hypercholesterolemia (ARH) protein plays a critical role in regulating plasma low density lipoprotein (LDL) levels. Inherited defects in ARH lead to a hypercholesterolemia that closely phenocopies that caused by a defective LDL receptor. The elevated serum LDL-cholesterol levels typical of ARH patients and the pronounced accumulation of the LDL receptor at the cell surface of hepatocytes in ARH-null mice argue that ARH operates by promoting the internalization of the LDL receptor within clathrin-coated vesicles. ARH contains an amino-terminal phosphotyrosine-binding domain that associates physically with the LDL receptor internalization sequence and with phosphoinositides. The carboxyl-terminal half of ARH contains a clathrin-binding sequence and a separate AP-2 adaptor binding region providing a plausible mechanism for how ARH can act as an endocytic adaptor or CLASP (clathrin-associated sorting protein) to couple LDL receptors with the clathrin machinery. Because the interaction with AP-2 is highly selective for the independently folded appendage domain of the beta2 subunit, we have characterized the ARH beta2 appendage-binding sequence in detail. Unlike the known alpha appendage-binding motifs, ARH requires an extensive sequence tract to bind the beta appendage with comparably high affinity. A minimal 16-residue sequence functions autonomously and depends upon ARH residues Asp253, Phe259, Leu262, and Arg266. We suggested that biased beta subunit engagement by ARH and the only other beta2 appendage selective adaptor, beta-arrestin, promotes efficient incorporation of this mechanistically distinct subset of CLASPs into clathrin-coated buds.

  16. Division of labor: subsets of dorsal-appendage-forming cells control the shape of the entire tube.

    PubMed

    Boyle, Michael J; French, Rachael L; Cosand, K Amber; Dorman, Jennie B; Kiehart, Daniel P; Berg, Celeste A

    2010-10-01

    The function of an organ relies on its form, which in turn depends on the individual shapes of the cells that create it and the interactions between them. Despite remarkable progress in the field of developmental biology, how cells collaborate to make a tissue remains an unsolved mystery. To investigate the mechanisms that determine organ structure, we are studying the cells that form the dorsal appendages (DAs) of the Drosophila melanogaster eggshell. These cells consist of two differentially patterned subtypes: roof cells, which form the outward-facing roof of the lumen, and floor cells, which dive underneath the roof cells to seal off the floor of the tube. In this paper, we present three lines of evidence that reveal a further stratification of the DA-forming epithelium. Laser ablation of only a few cells in the anterior of the region causes a disproportionately severe shortening of the appendage. Genetic alteration through the twin peaks allele of tramtrack69 (ttk(twk)), a female-sterile mutation that leads to severely shortened DAs, causes no such shortening when removed from a majority of the DA-forming cells, but rather, produces short appendages only when removed from cells in the very anterior of the tube-forming tissue. Additionally we show that heterotrimeric G-protein function is required for DA morphogenesis. Like TTK69, Gbeta 13F is not required in all DA-forming follicle cells but only in the floor and leading roof cells. The different phenotypes that result from removal of Gbeta 13F from each region demonstrate a striking division of function between different DA-forming cells. Gbeta mutant floor cells are unable to control the width of the appendage while Gbeta mutant leading roof cells fail to direct the elongation of the appendage and the convergent-extension of the roof-cell population.

  17. [The concise history of atrial fibrillation].

    PubMed

    Fazekas, Tamás

    2007-01-01

    The author reviews the history of atrial fibrillation, the most common sustained cardiac arrhythmia. The chaotic irregularity of arterial pulse was clearly acknowledged by most of physicians of the ancient China, Egypt and Greece. William Harvey (1578-1657), who first described the circulatory system appropriately, was probably the first to describe fibrillation of the auricles in animals in 1628. The French "clinical pathologist", Jean Baptist de Sénac (1693-1770) was the first who assumed a correlation between "rebellious palpitation" and stenosis of the mitral valve. Robert Adams (1791-1875) also reported in 1827 the association of irregular pulses and mitral stenosis. The discovery of digitalis leaf in 1785 by William Withering (1741-1799) brought relief to patients with atrial fibrillation and congestive heart failure by reducing the ventricular rate. From an analysis of simultaneously recorded arterial and venous pressure curves, the Scottish Sir James Mackenzie (1853-11925) demonstrated that a presystolic wave cannot be seen during "pulsus irregularis perpetuus", a term very first used by Heinrich Ewald Hering (1866-1948). Arthur Cushny (1866-1926) noted the similarity between pulse curves in clinical "delirium cordis" and those in dogs with atrial fibrillation. The first human ECG depicting atrial fibrillation was published by Willem Einthoven (1860-1927) in 1906. The proof of a direct connection between absolute arrhythmia and atrial fibrillation was established by two Viennese physicians, Carl Julius Rothberger and Heinrich Winterberg in 1909. Sir Thomas Lewis (1881-1945), the father of modem electrocardiography, studied electrophysiological characteristics of atrial fibrillation and has shown that its basic perpetuating mechanism is circus movement of electrical impulse (re-entry). After him, the major discoveries relating to the pathophysiology and clinical features of atrial fibrillation in the 20th century stemmed from Karel Frederick Wenckebach

  18. Antithrombotic Therapy for Atrial Fibrillation

    PubMed Central

    You, John J.; Singer, Daniel E.; Howard, Patricia A.; Lane, Deirdre A.; Eckman, Mark H.; Fang, Margaret C.; Hylek, Elaine M.; Schulman, Sam; Go, Alan S.; Hughes, Michael; Spencer, Frederick A.; Manning, Warren J.; Halperin, Jonathan L.

    2012-01-01

    Background: The risk of stroke varies considerably across different groups of patients with atrial fibrillation (AF). Antithrombotic prophylaxis for stroke is associated with an increased risk of bleeding. We provide recommendations for antithrombotic treatment based on net clinical benefit for patients with AF at varying levels of stroke risk and in a number of common clinical scenarios. Methods: We used the methods described in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines article of this supplement. Results: For patients with nonrheumatic AF, including those with paroxysmal AF, who are (1) at low risk of stroke (eg, CHADS2 [congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, prior stroke or transient ischemic attack] score of 0), we suggest no therapy rather than antithrombotic therapy, and for patients choosing antithrombotic therapy, we suggest aspirin rather than oral anticoagulation or combination therapy with aspirin and clopidogrel; (2) at intermediate risk of stroke (eg, CHADS2 score of 1), we recommend oral anticoagulation rather than no therapy, and we suggest oral anticoagulation rather than aspirin or combination therapy with aspirin and clopidogrel; and (3) at high risk of stroke (eg, CHADS2 score of ≥ 2), we recommend oral anticoagulation rather than no therapy, aspirin, or combination therapy with aspirin and clopidogrel. Where we recommend or suggest in favor of oral anticoagulation, we suggest dabigatran 150 mg bid rather than adjusted-dose vitamin K antagonist therapy. Conclusions: Oral anticoagulation is the optimal choice of antithrombotic therapy for patients with AF at high risk of stroke (CHADS2 score of ≥ 2). At lower levels of stroke risk, antithrombotic treatment decisions will require a more individualized

  19. Lunar influence on atrial fibrillation?

    PubMed

    Mikulecky, M; Valachova, A

    1996-08-01

    The most popular periodicities in biology and medicine-the circadians and circannuals-stem undoubtedly from the Earth's rotation and its revolution around the sun. The problem is how to explain the existence of circaseptan, i.e. 5-9-day, and other infradian rhythms. They may correspond to the lunar cycles and their 2nd to 6th harmonics. To test such hypothesis, the calendar dates of 127 attacks of atrial fibrillation in one male subject (M.M.) between 1980 and 1994 were transformed into the days numbered 0-29 for the synodic, and 0-26 for tropic lunar cycle. The daily frequencies obtained in this way were smoothed by moving averages of three successive days each. Considerable fluctuations of frequencies of attacks during both cycles were visible by inspection of the corresponding graphs, called lunar plexograms. Thus, a conspicuous nadir is found under the full moon in the synodic cycle, and a marked peak shortly after the extreme southern position of the moon in the tropic cycle. Halberg's cosinor analysis testing the presence of the 1st to 6th harmonic of either lunar cycle rejected the null hypothesis at the alpha = 0.05 level for all harmonics. Accordingly, the occurrence of attacks was cycling with the period lengths of synodic and tropic lunar cycles, and with those of their 1/2-1/6 period lengths, i.e. with a cluster of approximately circa(di)-septan rhythms. This conclusion is supported by similar findings obtained earlier for various medical and biological events.

  20. Dabigatran etexilate in atrial fibrillation.

    PubMed

    Vora, Amit

    2013-12-01

    Atrial fibrillation (AF) affects millions worldwide. Stroke is the most devastating complication of AF and is associated with a huge disease burden. As a preventive measure, anticoagulant therapy is recommended for most AF patients based on presence of stroke risk factors. For the past six decades warfarin remained the gold standard for stroke prevention in AF (SPAF). However, it is associated with numerous limitations such as a high risk of drug-drug, drug-food interactions and need for frequent INR (2-3) monitoring. Novel oral anticoagulant (NOAC) dabigatran etexilate is a selective, specific, reversible direct thrombin inhibitor that has been approved in India for SPAF and primary venous thromboembolism prevention. The efficacy and safety of dabigatran in AF has been established the "Randomized Evaluation of Long-Term Anticoagulant Therapy (RE-LY)", a randomized clinical trial. RE-LY (n = 18,113) demonstrated that the efficacy of dabigatran 110 mg BID was as good as well controlled warfarin and dabigatran 150 mg BID reduced the risk of ischaemic stroke by 25% (P = 0.03). Till date, 150mg dabigatran is the only NOAC offering a superior reduction in most commonly seen ischemic strokes due to AF compared to warfarin. Additionally, both doses of dabigatran significantly reduced the risk of total bleeds, intracranial, and life threatening bleeds versus warfarin (p < 0.05). Dabigatran has advantages over warfarin including predictable pharmacokinetic/pharmacodynamic profile, minimal drug-drug and no drug-food interactions while no monitoring is needed.The 150 mg dose of dabigatran should be considered in younger patients with a low risk of bleeding and good renal function to achieve a superior ischemic stroke reduction, whereas, the 110 mg dose should be considered in elderly patients, those with mild to moderate renal function or those with high risk of bleeding.

  1. A rare large right atrial myxoma with rapid growth rate.

    PubMed

    Kelly, Shawn C; Steffen, Kelly; Stys, Adam T

    2014-10-01

    Atrial myxomas are the most common benign intracavitary cardiac neoplasms. They most frequently occur in the left atrium. Right atrial tumors are rare, comprising 20 percent of myxomas achieving an incidence of 0.02 percent. Due to their rarity, right atrial tumor development and associated clinical symptoms has not been well described. The classical clinical triad for the presentation of left atrial myxomas--heart failure, embolic events, and constitutional symptoms--may not be applicable to right sided tumors. Also, natural development of myxoma is not well described, as surgical resection is the common practice. Previously ascribed growth rates of myxomas refer mostly to left atrial ones, as right atrial tumors are rare. We present a case of right atrial myxoma with growth rates exceeding those previously described.

  2. An improved method for echographic detection of left atrial enlargement

    NASA Technical Reports Server (NTRS)

    Brown, O. R.; Harrison, D. C.; Popp, R. L.

    1974-01-01

    Echographic dimensions of the aortic root and left atrium were compared in 170 patients in order to assess dilation of the left atrium with reference to the relatively nondistensible fibrous aortic root. In 50 patients without cause for left atrial or aortic enlargement, the ratio of left atrial/aortic root dimensions was 0.87 to 1.11. In 80 patients with known cause for left atrial enlargement, the left atrial/aortic root ratio was greater than or equal to 1.17. In 40 patients with isolated valve disease, dilation of both the aortic root and the left atrium resulted in a left atrial/aortic root dimension ratio less than 1.17 in some patients. Despite this consideration, the comparison of left atrial and aortic root dimension appears to be as specific as, and more sensitive than, previously proposed methods for the evaluation of left atrial enlargement.

  3. Expression of Distal-less, dachshund, and optomotor blind in Neanthes arenaceodentata (Annelida, Nereididae) does not support homology of appendage-forming mechanisms across the Bilateria

    PubMed Central

    Winchell, Christopher J.; Valencia, Jonathan E.

    2010-01-01

    The similarity in the genetic regulation of arthropod and vertebrate appendage formation has been interpreted as the product of a plesiomorphic gene network that was primitively involved in bilaterian appendage development and co-opted to build appendages (in modern phyla) that are not historically related as structures. Data from lophotrochozoans are needed to clarify the pervasiveness of plesiomorphic appendage-forming mechanisms. We assayed the expression of three arthropod and vertebrate limb gene orthologs, Distal-less (Dll), dachshund (dac), and optomotor blind (omb), in direct-developing juveniles of the polychaete Neanthes arenaceodentata. Parapodial Dll expression marks pre-morphogenetic notopodia and neuropodia, becoming restricted to the bases of notopodial cirri and to ventral portions of neuropodia. In outgrowing cephalic appendages, Dll activity is primarily restricted to proximal domains. Dll expression is also prominent in the brain. dac expression occurs in the brain, nerve cord ganglia, a pair of pharyngeal ganglia, presumed interneurons linking a pair of segmental nerves, and in newly differentiating mesoderm. Domains of omb expression include the brain, nerve cord ganglia, one pair of anterior cirri, presumed precursors of dorsal musculature, and the same pharyngeal ganglia and presumed interneurons that express dac. Contrary to their roles in outgrowing arthropod and vertebrate appendages, Dll, dac, and omb lack comparable expression in Neanthes appendages, implying independent evolution of annelid appendage development. We infer that parapodia and arthropodia are not structurally or mechanistically homologous (but their primordia might be), that Dll’s ancestral bilaterian function was in sensory and central nervous system differentiation, and that locomotory appendages possibly evolved from sensory outgrowths. PMID:21116826

  4. Cephalic and limb anatomy of a new Isoxyid from the Burgess Shale and the role of "stem bivalved arthropods" in the disparity of the frontalmost appendage.

    PubMed

    Aria, Cédric; Caron, Jean-Bernard

    2015-01-01

    We herein describe Surusicaris elegans gen. et sp. nov. (in Isoxyidae, amended), a middle (Series 3, Stage 5) Cambrian bivalved arthropod from the new Burgess Shale deposit of Marble Canyon (Kootenay National Park, British Columbia). Surusicaris exhibits 12 simple, partly undivided biramous trunk limbs with long tripartite caeca, which may illustrate a plesiomorphic "fused" condition of exopod and endopod. We construe also that the head is made of five somites (= four segments), including two eyes, one pair of anomalocaridid-like frontalmost appendages, and three pairs of poorly sclerotized uniramous limbs. This fossil may therefore be a candidate for illustrating the origin of the plesiomorphic head condition in euarthropods, and questions the significance of the "two-segmented head" in, e.g., fuxianhuiids. The frontalmost appendage in isoxyids is intriguingly disparate, bearing similarities with both dinocaridids and euarthropods. In order to evaluate the relative importance of bivalved arthropods, such as Surusicaris, in the hypothetical structuro-functional transition between the dinocaridid frontal appendage and the pre-oral-arguably deutocerebral-appendage of euarthropods, we chose a phenetic approach and computed morphospace occupancy for the frontalmost appendages of 36 stem and crown taxa. Results show different levels of evolutionary decoupling between frontalmost appendage disparity and body plans. Variance is greatest in dinocaridids and "stem bivalved" arthropods, but these groups do not occupy the morphospace homogeneously. Rather, the diversity of frontalmost appendages in "stem bivalved" arthropods, distinct in its absence of clear clustering, is found to link the morphologies of "short great appendages," chelicerae and antennules. This find fits the hypothesis of an increase in disparity of the deutocerebral appendage prior to its diversification in euarthropods, and possibly corresponds to its original time of development. The analysis of this

  5. Cephalic and Limb Anatomy of a New Isoxyid from the Burgess Shale and the Role of “Stem Bivalved Arthropods” in the Disparity of the Frontalmost Appendage

    PubMed Central

    Aria, Cédric; Caron, Jean-Bernard

    2015-01-01

    We herein describe Surusicaris elegans gen. et sp. nov. (in Isoxyidae, amended), a middle (Series 3, Stage 5) Cambrian bivalved arthropod from the new Burgess Shale deposit of Marble Canyon (Kootenay National Park, British Columbia). Surusicaris exhibits 12 simple, partly undivided biramous trunk limbs with long tripartite caeca, which may illustrate a plesiomorphic “fused” condition of exopod and endopod. We construe also that the head is made of five somites (= four segments), including two eyes, one pair of anomalocaridid-like frontalmost appendages, and three pairs of poorly sclerotized uniramous limbs. This fossil may therefore be a candidate for illustrating the origin of the plesiomorphic head condition in euarthropods, and questions the significance of the “two-segmented head” in, e.g., fuxianhuiids. The frontalmost appendage in isoxyids is intriguingly disparate, bearing similarities with both dinocaridids and euarthropods. In order to evaluate the relative importance of bivalved arthropods, such as Surusicaris, in the hypothetical structuro-functional transition between the dinocaridid frontal appendage and the pre-oral—arguably deutocerebral—appendage of euarthropods, we chose a phenetic approach and computed morphospace occupancy for the frontalmost appendages of 36 stem and crown taxa. Results show different levels of evolutionary decoupling between frontalmost appendage disparity and body plans. Variance is greatest in dinocaridids and “stem bivalved” arthropods, but these groups do not occupy the morphospace homogeneously. Rather, the diversity of frontalmost appendages in “stem bivalved” arthropods, distinct in its absence of clear clustering, is found to link the morphologies of “short great appendages,” chelicerae and antennules. This find fits the hypothesis of an increase in disparity of the deutocerebral appendage prior to its diversification in euarthropods, and possibly corresponds to its original time of development

  6. Expression of Distal-less, dachshund, and optomotor blind in Neanthes arenaceodentata (Annelida, Nereididae) does not support homology of appendage-forming mechanisms across the Bilateria.

    PubMed

    Winchell, Christopher J; Valencia, Jonathan E; Jacobs, David K

    2010-12-01

    The similarity in the genetic regulation of arthropod and vertebrate appendage formation has been interpreted as the product of a plesiomorphic gene network that was primitively involved in bilaterian appendage development and co-opted to build appendages (in modern phyla) that are not historically related as structures. Data from lophotrochozoans are needed to clarify the pervasiveness of plesiomorphic appendage-forming mechanisms. We assayed the expression of three arthropod and vertebrate limb gene orthologs, Distal-less (Dll), dachshund (dac), and optomotor blind (omb), in direct-developing juveniles of the polychaete Neanthes arenaceodentata. Parapodial Dll expression marks pre-morphogenetic notopodia and neuropodia, becoming restricted to the bases of notopodial cirri and to ventral portions of neuropodia. In outgrowing cephalic appendages, Dll activity is primarily restricted to proximal domains. Dll expression is also prominent in the brain. dac expression occurs in the brain, nerve cord ganglia, a pair of pharyngeal ganglia, presumed interneurons linking a pair of segmental nerves, and in newly differentiating mesoderm. Domains of omb expression include the brain, nerve cord ganglia, one pair of anterior cirri, presumed precursors of dorsal musculature, and the same pharyngeal ganglia and presumed interneurons that express dac. Contrary to their roles in outgrowing arthropod and vertebrate appendages, Dll, dac, and omb lack comparable expression in Neanthes appendages, implying independent evolution of annelid appendage development. We infer that parapodia and arthropodia are not structurally or mechanistically homologous (but their primordia might be), that Dll's ancestral bilaterian function was in sensory and central nervous system differentiation, and that locomotory appendages possibly evolved from sensory outgrowths.

  7. Computational models of atrial cellular electrophysiology and calcium handling, and their role in atrial fibrillation.

    PubMed

    Heijman, Jordi; Erfanian Abdoust, Pegah; Voigt, Niels; Nattel, Stanley; Dobrev, Dobromir

    2016-02-01

    The complexity of the heart makes an intuitive understanding of the relative contribution of ion channels, transporters and signalling pathways to cardiac electrophysiology challenging. Computational modelling of cardiac cellular electrophysiology has proven useful to integrate experimental findings, extrapolate results obtained in expression systems or animal models to other systems, test quantitatively ideas based on experimental data and provide novel hypotheses that are experimentally testable. While the bulk of computational modelling has traditionally been directed towards ventricular bioelectricity, increasing recognition of the clinical importance of atrial arrhythmias, particularly atrial fibrillation, has led to widespread efforts to apply computational approaches to understanding atrial electrical function. The increasing availability of detailed, atrial-specific experimental data has stimulated the development of novel computational models of atrial-cellular electrophysiology and Ca(2+) handling. To date, more than 300 studies have employed mathematical simulations to enhance our understanding of atrial electrophysiology, arrhythmogenesis and therapeutic responses. Future modelling studies are likely to move beyond current whole-cell models by incorporating new data on subcellular architecture, macromolecular protein complexes, and localized ion-channel regulation by signalling pathways. At the same time, more integrative multicellular models that take into account regional electrophysiological and Ca(2+) handling properties, mechano-electrical feedback and/or autonomic regulation will be needed to investigate the mechanisms governing atrial arrhythmias. A combined experimental and computational approach is expected to provide the more comprehensive understanding of atrial arrhythmogenesis that is required to develop improved diagnostic and therapeutic options. Here, we review this rapidly expanding area, with a particular focus on Ca(2+) handling, and

  8. Effect of years of endurance exercise on risk of atrial fibrillation and atrial flutter.

    PubMed

    Myrstad, Marius; Nystad, Wenche; Graff-Iversen, Sidsel; Thelle, Dag S; Stigum, Hein; Aarønæs, Marit; Ranhoff, Anette H

    2014-10-15

    Emerging evidence suggests that endurance exercise increases the risk for atrial fibrillation (AF) in men, but few studies have investigated the dose-response relation between exercise and risk for atrial arrhythmias. Both exposure to exercise and reference points vary among studies, and previous studies have not differentiated between AF and atrial flutter. The aim of this study was to assess the risk for atrial arrhythmias by cumulative years of regular endurance exercise in men. To cover the range from physical inactivity to long-term endurance exercise, the study sample in this retrospective cohort study was based on 2 distinct cohorts: male participants in a long-distance cross-country ski race and men from the general population, in total 3,545 men aged ≥ 53 years. Arrhythmia diagnoses were validated by electrocardiograms during review of medical records. Regular endurance exercise was self-reported by questionnaire. A broad range of confounding factors was available for adjustment. The adjusted odds ratios per 10 years of regular endurance exercise were 1.16 (95% confidence interval 1.06 to 1.29) for AF and 1.42 (95% confidence interval 1.20 to 1.69) for atrial flutter. In stratified analyses, the associations were significant in cross-country skiers and in men from the general population. In conclusion, cumulative years of regular endurance exercise were associated with a gradually increased risk for AF and atrial flutter.

  9. The effect of asanguinous cardioplegic arrest on atrial preservation using atrial ATP as a marker.

    PubMed

    Hines, G L; Scheaffer, P; Williams, L; Mantell, P; Cheifitz, P

    1990-01-01

    Changes in atrial adenosine triphosphate (ATP) and the presence of postoperative arrhythmias were studied in 14 patients during routine coronary artery bypass grafting to 1) attempt to evaluate atrial preservation, and 2) determine if a relationship exists between changes in ATP and the development of postoperative arrhythmias. Atrial biopsies were obtained at the time of cannulation (preischemic sample) and after the removal of the aortic crossclamp (postischemic sample). Methods of myocardial protection included systemic hypothermia (28 degrees C), periodic reinfusion of crystalloid cardioplegia into the aortic root and completed vein grafts, and iced slush in the pericardial well. Atrial temperature was monitored. Preischemic ATP was 0.412 +/- 0.32 mu mol/gm, and the postischemic value was 0.220 +/- 0.13 mu mol/gm (p less than .02). Atrial temperature routinely decreased to 13-18 degrees C after cardioplegic infusion but rose to 24 degrees C between infusions. There was no correlation between postoperative supraventricular arrhythmias (4 patients) and changes in ATP. In conclusion, routine coronary artery bypass grafting with standard methods of cardiac preservation does not appear to satisfactorily preserve atrial tissue. The clinical correlation and significance of this remains to be elucidated.

  10. An unusual presentation of atrial myxoma

    PubMed Central

    Anpalakhan, Shaemala; Ramasamy, Dewi; Fan, Kin Sing

    2014-01-01

    Myxomas are uncommon primary cardiac tumours that usually affect the left atrium. We herein report the case of a patient who presented with right heart failure and proteinuria, leading to the diagnosis of atrial myxoma. Surgical resection resulted in resolution of the patient’s symptoms. PMID:25631903

  11. Spinal cord ischemia and left atrial myxoma.

    PubMed

    Hirose, G; Kosoegawa, H; Takado, M; Shimazaki, K; Murakami, E

    1979-07-01

    A 62-year-old man had an acute, transient, flaccid paraplegia. Examination showed a primary cardiac tumor with emboli to major branches of the aorta. A myxoma was removed from the left atrium, and normal function returned. Left atrial myxoma should be suspected as a cause for embolism to the CNS.

  12. Atrial and ventricular tachyarrhythmias in military personnel.

    PubMed

    Posselt, Bonnie N; Cox, A T; D'Arcy, J; Rooms, M; Saba, M

    2015-09-01

    Although rare, sudden cardiac death does occur in British military personnel. In the majority of cases, the cause is considered to be a malignant ventricular tachyarrhythmia, which can be precipitated by a number of underlying pathologies. Conversely, a tachyarrhythmia may have a more benign and treatable cause, yet the initial clinical symptoms may be similar, making differentiation difficult. This is an overview of the mechanisms underlying the initiation and propagation of arrhythmias and the various pathological conditions that predispose to arrhythmia genesis, classified according to which parts of the heart are involved: atrial tachyarrhythmias, atrial and ventricular, as well as those affecting the ventricles alone. It encompasses atrial tachycardia, atrial flutter, supraventricular tachycardias and ventricular tachycardias, including the more commonly encountered inherited primary electrical diseases, also known as the channelopathies. The clinical features, investigation and management strategies are outlined. The occupational impact-in serving military personnel and potential recruits-is described, with explanations relating to the different conditions and their specific implication on continued military service.

  13. Obstructive Sleep Apnea and Atrial Arrhythmogenesis

    PubMed Central

    Hohl, Mathias; Linz, Benedikt; Böhm, Michael; Linz, Dominik

    2014-01-01

    Atrial fibrillation (AF) is the most common sustained arrhythmia and is associated with relevant morbidity and mortality. Besides hypertension, valvular disease and cardiomyopathy, mainly ischemic and dilated, also other conditions like obesity, alcohol abusus, genetic factors and obstructive sleep apnea (OSA) are discussed to contribute to the progression from paroxysmal to persistent AF. The prevalence of OSA among patients with AF is 40-50%. OSA is characterized by periodic or complete cessation of effective breathing during sleep due to obstruction of the upper airways. Obstructive respiratory events result in acute intrathoracic pressure swings and profound changes in blood gases together leading to atrial stretch and acute sympatho-vagal dysbalance resulting in acute apnea related to electrophysiological and hemodynamic alterations. Additionally, repetitive obstructive events in patients with OSA may lead to sympathetic and neurohumoral activation and subsequent structural and functional changes in the atrium creating an arrhythmogenic substrate for AF in the long run. This review focuses on the acute and chronic effects of negative thoracic pressure swings, changes in blood pressure and sympatho-vagal dysbalance induced by obstructive respiratory events on atrial electrophysiology and atrial structure in patients with obstructive sleep apnea. PMID:25004989

  14. Initial experience with single lead intracardial cardioversion for refractory atrial fibrillation

    PubMed Central

    van de Klippe, H.A.; Allaart, C.P.; Ruiter, J.H.

    2001-01-01

    Background Chronic atrial fibrillation (AF) is a common arrhythmia, associated with a substantial morbidity (thromboemboli, worsening left ventricular function). Established therapy for pharmacological refractory AF is high-energy trans-thoracic electric cardioversion (TTCV), but this strategy is ineffective for 10-30% of the patients. The purpose of the present study is to establish the safety and efficacy of low-energy intracardiac cardioversion (ICCV) with a relatively new balloon-guided single-catheter system with dual chamber pacing possibility for this group of patients. Methods Patients in whom an attempt to restore sinus rhythm (SR) by TTCV under antiarrhythmic therapy failed were eligible for the study. For the ICCV-attempt, a single flow-guided atrial cardioversion catheter was used. Low-energy biphasic shocks of increasing energy (6-15 J) were delivered, if necessary in combination with intravenous amiodarone, until SR was restored. In case of early recurrence of AF, another attempt was made with immediate post-shock overdrive pacing (AOO) in order to suppress premature atrial activity. Results Initially, 14 of the 16 treated patients (90%) were converted to SR successfully. In eight patients additional amiodarone i.v. was administered and in six patients atrial overpacing was used after ICCV. In seven and five patients, respectively, these strategies were successful. Long-term follow-up (1-3 months) showed that in nine patients (56%) SR was preserved; eight of them on oral amiodarone. No adverse events were seen during the procedure and follow-up, especially no bleedings, despite puncturing under adequate anticoagulation therapy. Conclusion ICCV using a single atrial cardioversion catheter is a safe and effective method to restore SR in patients in whom TTCV failed previously. Long-term follow-up of this procedure is comparable to that of other studies. Results are influenced by antiarrhythmic drug therapy, compliance and patient selection. Images

  15. Stroke as the First Manifestation of Atrial Fibrillation

    PubMed Central

    Jaakkola, Jussi; Mustonen, Pirjo; Kiviniemi, Tuomas; Hartikainen, Juha E. K.; Palomäki, Antti; Hartikainen, Päivi; Nuotio, Ilpo; Ylitalo, Antti; Airaksinen, K. E. Juhani

    2016-01-01

    Atrial fibrillation may remain undiagnosed until an ischemic stroke occurs. In this retrospective cohort study we assessed the prevalence of ischemic stroke or transient ischemic attack as the first manifestation of atrial fibrillation in 3,623 patients treated for their first ever stroke or transient ischemic attack during 2003–2012. Two groups were formed: patients with a history of atrial fibrillation and patients with new atrial fibrillation diagnosed during hospitalization for stroke or transient ischemic attack. A control group of 781 patients with intracranial hemorrhage was compiled similarly to explore causality between new atrial fibrillation and stroke. The median age of the patients was 78.3 [13.0] years and 2,009 (55.5%) were women. New atrial fibrillation was diagnosed in 753 (20.8%) patients with stroke or transient ischemic attack, compared to 15 (1.9%) with intracranial hemorrhage. Younger age and no history of coronary artery disease or other vascular diseases, heart failure, or hypertension were the independent predictors of new atrial fibrillation detected concomitantly with an ischemic event. Thus, ischemic stroke was the first clinical manifestation of atrial fibrillation in 37% of younger (<75 years) patients with no history of cardiovascular diseases. In conclusion, atrial fibrillation is too often diagnosed only after an ischemic stroke has occurred, especially in middle-aged healthy individuals. New atrial fibrillation seems to be predominantly the cause of the ischemic stroke and not triggered by the acute cerebrovascular event. PMID:27936187

  16. Molecular developmental evidence for a subcoxal origin of pleurites in insects and identity of the subcoxa in the gnathal appendages.

    PubMed

    Coulcher, Joshua F; Edgecombe, Gregory D; Telford, Maximilian J

    2015-10-28

    Pleurites are chitinous plates in the body wall of insects and myriapods. They are believed to be an adaptation to locomotion on land but their developmental and evolutionary origins are unclear. A widely endorsed explanation for their origin is through toughening pre-existing parts of the body wall; in contrast, the subcoxal theory suggests pleurites derive from a redeployment of the proximal-most section of the leg, the subcoxa. Here, by studying expression of appendage patterning genes in embryos and larvae of the beetle Tribolium castaneum, we provide the first molecular evidence for the existence of a cryptic subcoxal segment in developing legs. We follow this structure during development and show that the embryonic subcoxa later forms the pleurites of the larva as predicted by the subcoxal theory. Our data also demonstrate that subcoxal segments are present in all post-antennal appendages, including the first molecular evidence of a two-segmented mandible with a subcoxal segment in insects.

  17. Endurance sport practice as a risk factor for atrial fibrillation and atrial flutter.

    PubMed

    Mont, Lluís; Elosua, Roberto; Brugada, Josep

    2009-01-01

    Although the benefits of regular exercise in controlling cardiovascular risk factors have been extensively proven, little is known about the long-term cardiovascular effects of regular and extreme endurance sport practice, such as jogging, cycling, rowing, swimming, etc. Recent data from a small series suggest a relationship between regular, long-term endurance sport practice and atrial fibrillation (AF) and flutter. Reported case control studies included less than 300 athletes, with mean age between 40 and 50. Most series recruited only male patients, or more than 70% males, who had been involved in intense training for many years. Endurance sport practice increases between 2 and 10 times the probability of suffering AF, after adjusting for other risk factors. The possible mechanisms explaining the association remain speculative. Atrial ectopic beats, inflammatory changes, and atrial size have been suggested. Some of the published studies found that atrial size was larger in athletes than in controls, and this was a predictor for AF. It has also been shown that the left atrium may be enlarged in as many as 20% of competitive athletes. Other proposed mechanisms are increased vagal tone and bradycardia, affecting the atrial refractory period; however, this may facilitate rather than cause the arrhythmia. In summary, recent data suggest an association between endurance sport practice and atrial fibrillation and flutter. The underlying mechanism explaining this association is unclear, although structural atrial changes (dilatation and fibrosis) are probably present. Larger longitudinal studies and mechanistic studies are needed to further characterize the association to clarify whether a threshold limit for the intensity and duration of physical activity may prevent AF, without limiting the cardiovascular benefits of exercise.

  18. Effectiveness of Early Invasive Therapy for Atrial Tachycardia in Adult Atrial-Baffle Survivors

    PubMed Central

    Zaidi, Ali N.; Morrison, Justin; Daniels, Curt J.; Kalbfleisch, Steven; Kertesz, Naomi J.

    2017-01-01

    Adults who underwent complex atrial baffling as children via Mustard or Senning procedures are at heightened risk for atrial arrhythmias. Antiarrhythmic therapies are typically ineffective in this population. Accordingly, our team of pediatric and adult electrophysiologists investigated the effectiveness of early invasive transbaffle-access techniques to perform early radiofrequency ablation at the source of these clinically significant arrhythmias. For this retrospective study, we selected 11 adult survivors of atrial baffling (mean age, 34 ± 9 yr) who underwent clinically indicated electrophysiologic study after no more than one trial of antiarrhythmic therapy. Using transbaffle-access techniques and 3-dimensional mapping of the venous atria, we found 12 inducible arrhythmias in 10 patients: intra-atrial reentrant tachycardia (n=6), atrioventricular nodal reentrant tachycardia (n=3), focal atrial tachycardia (n=2), and repetitive double firing of the atrioventricular node (n=1). Defining success as short- and midterm freedom from arrhythmia, we analyzed outcomes of radiofrequency ablation at 1 and 6 months. At 1 month, ablation was 100% successful. At 6 months, after 11 ablations in 9 patients, 5 patients had no clinical recurrence, 2 had improved arrhythmia control from minimal medical therapy, and 2 were to undergo repeat study for recurrent tachycardia. In the recurrence-free patients, arrhythmias during electrophysiology study matched the types found clinically before the study. To our knowledge, this is the largest one-year cohort of adult survivors of atrial baffling to have undergone study by a combined pediatric–adult electrophysiology team. We conclude that early invasive transbaffle access for ablating diverse atrial tachyarrhythmias was effective in these patients. PMID:28265208

  19. [Differences in atrial remodelling between right and left atria in patients with chronic atrial fibrillation].

    PubMed

    Tamargo Menéndez, Juan

    2011-01-01

    Atrial fibrillation starts in the left atrium and from there the activity invades the atrial tissues and causes an inhomogeneous shortening the duration of atrial action potential duration and refractoriness. The purpose of this study was to compare the voltage-dependent potassium currents in human cells isolated from the right and left atria and to determine whether electrical remodeling produced by chronic atrial fibrillation (CAF) differentially affects voltage-dependent potassium currents involved in atrial repolarization in each atrium as compared to sinus rhythm (SR). The currents were recorded using the whole-cell configuration of the patch-clamp technique. We found that in atrial cardiomyocytes of patients both in SR and in CAF there are three types of cells according to their main voltage-dependent repolarizing potassium current: the Ca(2+)-independent 4-aminopyridine sensitive component of the transient outward current (I(to1)) and the ultrarapid (I(Kur)), rapid (I(Kr)) and slow (I(Ks)) components of the delayed rectifier current. CAF differentially modified the proportion of these 3 types of cells on each atrium: CAF reduced the I(to1) more markedly in the left than in the right atria, while I(Kur) was more markedly reduced in the right than in the left atria. Interestingly, in both atria, CAF markedly increased the I(Ks). This increase was enhanced by isoproterenol and suppressed by atenolol. These changes produce a non-uniform shortening of atrial repolarization that facilitates the reentry of the cardiac impulse and the perpetuation of the arrhythmia.

  20. 78 FR 11207 - Clinical Study Designs for Surgical Ablation Devices for Treatment of Atrial Fibrillation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-15

    ... Treatment of Atrial Fibrillation; Guidance for Industry and Food and Drug Administration Staff; Availability... Ablation Devices for Treatment of Atrial Fibrillation.'' This guidance provides FDA's recommendations on clinical trial designs for surgical ablation devices intended for the treatment of atrial...

  1. The effect of discrete stimulation of carotid body chemoreceptors on atrial natriuretic peptide in anaesthetized dogs.

    PubMed Central

    al-Obaidi, M; Whitaker, E M; Karim, F

    1991-01-01

    1. In seven chloralose-anaesthetized and artificially ventilated beagles, the carotid sinus regions were vascularly isolated and perfused with either arterial or mixed (arterial and venous) blood (PO2 46.4 +/- 1.5 mmHg, mean +/- S.E.M.) to stimulate the chemoreceptors at constant flow and pressure. Cervical vagosympathetic trunks were ligated in all dogs, and gallamine triethiodide (2.0 mg kg-1 h-1, I.V.) was given in five dogs. Right atrial pressure was measured in all dogs, and left atrial pressure in four dogs. Mean aortic pressure was held constant (91.0 +/- 3.0 mmHg) by means of a reservoir connected to the animal via the common carotid and femoral arteries. Plasma atrial natriuretic peptide (ANP) was measured by radioimmunoassay and urinary sodium by flame photometry. 2. In seven dogs with mean carotid sinus pressure maintained at 96.0 +/- 4.3 mmHg, stimulation of the carotid chemoreceptors for 25 min produced significant increases in left atrial pressure of 41.2 +/- 3.3% (n = 4; P less than 0.005) from 5.4 +/- 0.6 cmH2O and of 30.9 +/- 4.5% (n = 7; P less than 0.002) in ANP from 31.6 +/- 2.1 pg ml-1. However, chemoreceptor stimulation produced significant decreases in urine flow rate of 26.1 +/- 1.9% (n = 9; P less than 0.001) from 0.29 +/- 0.03 ml min-1 (100 g kidney weight)-1 and sodium excretion of 29.0 +/- 2.3% (P less than 0.001) from 8.5 +/- 1.7 mumol min-1 (100 g kidney weight)-1 but right atrial pressure and heart rate did not change significantly. In three of the dogs, beta-adrenoceptor blockade by atenolol (2 mg kg-1, I.V.) greatly reduced the effects of chemoreceptor stimulation on plasma levels of ANP. 3. The results show, for the first time, that discrete stimulation of the carotid chemoreceptors caused an increase in plasma ANP levels, probably due to the reflex increase in atrial pressure that results from an inhibition of the cardiac sympathetic nerves, and an increase in venous return from a reduction of peripheral vascular capacitance. PMID

  2. Cor Triatriatum Sinister Identified after New Onset Atrial Fibrillation in an Elderly Man

    PubMed Central

    Zepeda, Ignacio A.; Morcos, Peter; Castellanos, Luis R.

    2014-01-01

    A 73-year-old man with new onset atrial fibrillation with rapid ventricular response underwent transthoracic echocardiography that revealed an echogenic linear structure along the left atrium, suggestive of cor triatriatum sinister (CTS). CTS was confirmed with transesophageal echocardiography which demonstrated a proximal accessory atrium receiving pulmonary venous flow separated from a distal true atrium by a fibromuscular membrane with a large fenestration allowing flow between the chambers. In CTS, the left atrium is divided into proximal and distal chambers by a fenestrated fibromuscular septum. This cardiac anomaly accounts for 0.1% of cases of congenital heart disease and rarely presents in adults. CTS is primarily diagnosed with echocardiography and is associated with left atrial enlargement and development of atrial fibrillation. Treatment options depend on size of the communication between proximal and distal chambers, the gradient across the membrane, and the position of pulmonary veins. In some instances, surgical resection of the membrane that divides the left atrium is warranted. PMID:25614746

  3. Evolution of a Novel Appendage Ground Plan in Water Striders Is Driven by Changes in the Hox Gene Ultrabithorax

    PubMed Central

    Khila, Abderrahman; Abouheif, Ehab; Rowe, Locke

    2009-01-01

    Water striders, a group of semi-aquatic bugs adapted to life on the water surface, have evolved mid-legs (L2) that are long relative to their hind-legs (L3). This novel appendage ground plan is a derived feature among insects, where L2 function as oars and L3 as rudders. The Hox gene Ultrabithorax (Ubx) is known to increase appendage size in a variety of insects. Using gene expression and RNAi analysis, we discovered that Ubx is expressed in both L2 and L3, but Ubx functions to elongate L2 and to shorten L3 in the water strider Gerris buenoi. Therefore, within hemimetabolous insects, Ubx has evolved a new expression domain but maintained its ancestral elongating function in L2, whereas Ubx has maintained its ancestral expression domain but evolved a new shortening function in L3. These changes in Ubx expression and function may have been a key event in the evolution of the distinct appendage ground plan in water striders. PMID:19649305

  4. Evolution of a novel appendage ground plan in water striders is driven by changes in the Hox gene Ultrabithorax.

    PubMed

    Khila, Abderrahman; Abouheif, Ehab; Rowe, Locke

    2009-07-01

    Water striders, a group of semi-aquatic bugs adapted to life on the water surface, have evolved mid-legs (L2) that are long relative to their hind-legs (L3). This novel appendage ground plan is a derived feature among insects, where L2 function as oars and L3 as rudders. The Hox gene Ultrabithorax (Ubx) is known to increase appendage size in a variety of insects. Using gene expression and RNAi analysis, we discovered that Ubx is expressed in both L2 and L3, but Ubx functions to elongate L2 and to shorten L3 in the water strider Gerris buenoi. Therefore, within hemimetabolous insects, Ubx has evolved a new expression domain but maintained its ancestral elongating function in L2, whereas Ubx has maintained its ancestral expression domain but evolved a new shortening function in L3. These changes in Ubx expression and function may have been a key event in the evolution of the distinct appendage ground plan in water striders.

  5. The regeneration blastema of lizards: an amniote model for the study of appendage replacement.

    PubMed

    Gilbert, E A B; Delorme, S L; Vickaryous, M K

    2015-04-01

    Although amniotes (reptiles, including birds, and mammals) are capable of replacing certain tissues, complete appendage regeneration is rare. Perhaps the most striking example is the lizard tail. Tail loss initiates a spontaneous epimorphic (blastema-mediated) regenerative program, resulting in a fully functional but structurally non-identical replacement. Here we review lizard tail regeneration with a particular focus on the blastema. In many lizards, the original tail has evolved a series of fracture planes, anatomical modifications that permit the tail to be self-detached or autotomized. Following tail loss, the wound site is covered by a specialized wound epithelium under which the blastema develops. An outgrowth of the spinal cord, the ependymal tube, plays a key role in governing growth (and likely patterning) of the regenerate tail. In some species (e.g., geckos), the blastema forms as an apical aggregation of proliferating cells, similar to that of urodeles and teleosts. For other species (e.g., anoles) the identification of a proliferative blastema is less obvious, suggesting an unexpected diversity in regenerative mechanisms among tail-regenerating lizards.

  6. A vertex specific dorsal selector Dve represses the ventral appendage identity in Drosophila head.

    PubMed

    Kiritooshi, Naruto; Yorimitsu, Takeshi; Shirai, Tetsuya; Puli, Oorvashi Roy; Singh, Amit; Nakagoshi, Hideki

    2014-08-01

    Developmental fields are subdivided into lineage-restricted cell populations, known as compartments. In the eye imaginal disc of Drosophila, dorso-ventral (DV) lineage restriction is the primary event, whereas antero-posterior compartment boundary is the first lineage restriction in other imaginal discs. The Iroquois complex (Iro-C) genes function as dorsal selectors and repress the default, ventral, identity in the eye-head primordium. In Iro-C mutant clones, change of the dorsal identity to default ventral fate leads to generation of ectopic DV boundary, which results in dorsal eye enlargement, and duplication of ventral appendages like antenna and maxillary palp. Similar phenotypes were observed in heads with defective proventriculus (dve) mutant clones. Here, we show that the homeobox gene dve is a downstream effector of Iro-C in the dorsal head capsule (vertex) specification and represses the ventral (antennal) identity. Two homeodomain proteins Distal-less (Dll) and Homothorax (Hth) are known to be determinants of the antennal identity. Ectopic antenna formation in heads with dve mutant clones was associated with ectopic Dll expression and endogenous Hth expression in the vertex region. Interestingly, dve Dll double mutant clones could also induce ectopic antennae lacking the distal structures, suggesting that the Dve activity is crucial for repressing inappropriate antenna-forming potential in the vertex region. Our results clearly indicate that not only the activation of effector genes to execute developmental program but also the repression of inappropriate program is crucial for establishment of the organ identity.

  7. Current problems concerning parasitology and mycology with regard to diseases of the skin and its appendages.

    PubMed

    Błaszkowska, Joanna; Wójcik, Anna

    2012-01-01

    Current issues concerning Parasitology and Mycology with regard to diseases of the skin and its appendages are presented. Aspects of diagnostics, clinical picture and therapy of skin and nail mycoses, as well as difficulties in the diagnosis and treatment of both native parasitoses (toxoplasmosis) and imported human tropical parasitoses (malaria, filariosis) have been emphasised. The clinical importance of environmental mould fungi in nosocomial infections and fungal meningitis, as well as selected properties of fungi isolated from patients with head and neck neoplasms treated by radiotherapy are discussed. Other mycological topics include the characteristics of newly-synthesized thiosemicarbazides and thiadiazoles as potential drugs against toxoplasmosis and their biological activity against Toxoplasma gondii tachyzoites, selected molecular mechanisms of resistance to azoles, Candida albicans strains and a new tool (barcoding DNA) for describing the biodiversity of potential allergenic molds. The importance of environmental factors in pathogenesis of mycoses and parasitoses is noted. The characteristics of pathogenic fungi isolated from natural ponds in Bialystok and potentially pathogenic yeast-like fungi isolated from children's recreation areas in Lodz are presented. The ongoing problem of anthropozoonoses is considered, as are the roles of stray cats and dogs in contaminating soil with the developing forms of intestinal parasites. The characteristics of the human microbiome, including population composition, activity and their importance in normal human physiology, are presented, as are the major goals of the Human Microbiome Project initiated by National Institutes of Health (NIH).

  8. Trichoderma reesei XYN VI--a novel appendage-dependent eukaryotic glucuronoxylan hydrolase.

    PubMed

    Biely, Peter; Puchart, Vladimír; Stringer, Mary Ann; Mørkeberg Krogh, Kristian B R

    2014-09-01

    Expression of a Trichoderma reesei gene coding for a putative GH30 xylanase in Aspergillus oryzae led to isolation and purification of a novel xylanase exhibiting catalytic properties different from those of the previously characterized GH30 xylanase XYN IV of T. reesei. The novel enzyme, named XYN VI, exhibited catalytic properties similar to appendage-dependent GH30 glucuronoxylanases previously recognized only in bacteria. XYN VI showed high specific activity only on xylans or xylooligosaccharides containing 4-O-methyl-D-glucuronic acid or D-glucuronic acid side substituents. The cleavage of the main chain takes place primarily at the second glycosidic linkage from the branch towards the reducing end of the polysaccharides or aldouronic acids. These catalytic properties resemble bacterial GH30 glucuronoxylanases, although the recognition of the uronic acid side chains by XYN VI is apparently based on interaction of the substrate with other amino acids. Moreover, in contrast to bacterial enzymes, XYN VI is also capable of slower but significant cleavage of unsubstituted parts of xylan and acidic xylooligosaccharides. The data point to a great catalytic diversity of xylanases produced by the most extensively studied cellulolytic fungus.

  9. The regeneration blastema of lizards: an amniote model for the study of appendage replacement

    PubMed Central

    Gilbert, E. A. B.; Delorme, S. L.

    2015-01-01

    Abstract Although amniotes (reptiles, including birds, and mammals) are capable of replacing certain tissues, complete appendage regeneration is rare. Perhaps the most striking example is the lizard tail. Tail loss initiates a spontaneous epimorphic (blastema‐mediated) regenerative program, resulting in a fully functional but structurally non‐identical replacement. Here we review lizard tail regeneration with a particular focus on the blastema. In many lizards, the original tail has evolved a series of fracture planes, anatomical modifications that permit the tail to be self‐detached or autotomized. Following tail loss, the wound site is covered by a specialized wound epithelium under which the blastema develops. An outgrowth of the spinal cord, the ependymal tube, plays a key role in governing growth (and likely patterning) of the regenerate tail. In some species (e.g., geckos), the blastema forms as an apical aggregation of proliferating cells, similar to that of urodeles and teleosts. For other species (e.g., anoles) the identification of a proliferative blastema is less obvious, suggesting an unexpected diversity in regenerative mechanisms among tail‐regenerating lizards. PMID:27499867

  10. Scrotal Exploration for Testicular Torsion and Testicular Appendage Torsion: Emergency and Reality

    PubMed Central

    Yu, You; Zhang, Feng; An, Qun; Wang, Long; Li, Chao; Xu, Zhilin

    2015-01-01

    Background: Scrotal exploration is considered the procedure of choice for acute scrotum. Objectives: We evaluated the importance of early diagnosis and testicular salvage on the therapeutic outcomes of patients with pediatric testicular torsion (TT) and testicular appendage torsion (TAT) in our geographic area. Patients and Methods: We performed a retrospective database analysis of patients who underwent emergency surgery for TT or TAT between January 1996 and June 2009. Patient history, physical examination findings, laboratory test results, color Doppler sonography (CDS) results, and surgical findings were reviewed. Results: A total of 65 cases were included in our analysis. Forty-two cases were followed up for at least 3 months. Testicular tenderness was identified as the major clinical manifestation of TT, while only a few patients with TAT presented with swelling. CDS was an important diagnostic modality. The orchiectomy rate was 71% in the TT group. Conclusions: Cases of acute scrotum require attention in our area. Early diagnosis and scrotal exploration could salvage the testis or preserve normal function without the need for surgery. PMID:26199690

  11. Exploring the biology of the nail: An intriguing but less-investigated skin appendage.

    PubMed

    Saito, Masataka; Ohyama, Manabu; Amagai, Masayuki

    2015-09-01

    The nail is a highly keratinized structure covering the tip of the digit, and considered to have several important functions in our daily life. In recent years, as biological aspects of the nail organ have been characterized, we realize that the nail unit and the hair follicle share various biological and immunological features. In particular, development and homeostasis of the nail unit also requires intimate epithelial-mesenchymal interactions that involve signaling pathways such as Wnt. There is also a striking immunological resemblance between both appendages, since the nail matrix, like the anagen hair bulb and the bulge, was shown to present unique characteristics of an immune privileged site. On the other hand, considerable progress in identifying nail stem cells has succeeded in locating putative stem cell niches in the nail unit. In this context, it is intriguing that nail stem cells residing in the nail matrix were recently shown to possess the ability to organize the process leading to digit regeneration. Further elucidation of signaling pathways governing epithelial-mesenchymal interactions in the nail unit seems to be a key to develop a novel therapeutic tool to treat amputees using nail epithelium. However, it is at least certain that the nail unit has a promising potential for the future of regenerative medicine. This review explores the biology of the nail organ by focusing on intriguing knowledge gained from recent studies.

  12. [Atrial fibrillation as consequence and cause of structural changes of atria].

    PubMed

    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.

  13. Atrial Myxoma in a Patient with Hypertrophic Cardiomyopathy

    PubMed Central

    Abdou, Mahmoud; Hayek, Salim; Williams, Byron R.

    2013-01-01

    Atrial myxoma is the most common primary cardiac tumor. Patients with atrial myxoma typically present with obstructive, embolic, or systemic symptoms; asymptomatic presentation is very rare. To our knowledge, isolated association of atrial myxoma with hypertrophic cardiomyopathy has been reported only once in the English-language medical literature. We report the case of an asymptomatic 71-year-old woman with known hypertrophic cardiomyopathy in whom a left atrial mass was incidentally identified on cardiac magnetic resonance images. After surgical excision of the mass and partial excision of the left atrial septum, histopathologic analysis confirmed the diagnosis of atrial myxoma. The patient was placed on preventive implantable cardioverter-defibrillator therapy and remained asymptomatic. The management of asymptomatic cardiac myxoma is a topic of debate, because no reports definitively favor either conservative or surgical measures. PMID:24082380

  14. Functional analyses in the milkweed bug Oncopeltus fasciatus (Hemiptera) support a role for Wnt signaling in body segmentation but not appendage development.

    PubMed

    Angelini, David R; Kaufman, Thomas C

    2005-07-15

    Specification of the proximal-distal (PD) axis of insect appendages is best understood in Drosophila melanogaster, where conserved signaling molecules encoded by the genes decapentaplegic (dpp) and wingless (wg) play key roles. However, the development of appendages from imaginal discs as in Drosophila is a derived state, while more basal insects produce appendages from embryonic limb buds. Therefore, the universality of the Drosophila limb PD axis specification mechanism has been debated since dpp expression in more basal insect species differs dramatically from Drosophila. Here, we test the function of Wnt signaling in the development of the milkweed bug Oncopeltus fasciatus, a species with the basal state of appendage development from limb buds. RNA interference of wg and pangolin (pan) produce defects in the germband and eyes, but not in the appendages. Distal-less and dachshund, two genes regulated by Wg signaling in Drosophila and expressed in specific PD domains along the limbs of both species, are expressed normally in the limbs of pan-depleted Oncopeltus embryos. Despite these apparently paradoxical results, Armadillo protein, the transducer of Wnt signaling, does not accumulate properly in the nuclei of cells in the legs of pan-depleted embryos. In contrast, engrailed RNAi in Oncopeltus produces cuticular and appendage defects similar to Drosophila. Therefore, our data suggest that Wg signaling is functionally conserved in the development of the germband, while it is not essential in the specification of the limb PD axis in Oncopeltus and perhaps basal insects.

  15. Unusual case of right atrial reinfarction.

    PubMed

    Radojevic, Nemanja; Savic, Slobodan; Aleksic, Vuk; Cukic, Dragana

    2012-02-01

    It is well known that atrial infarctions are rare comparing to the ventricular. They cannot easily be verified on ECG and the standard autopsy technique does not include a detailed review of the atrial wall, so the atrial infarction often remains undiagnosed. A 63-year-old male was treated and died in an intensive care unit due to decompensated liver insufficiency and cardiac disease following long-lasting alcohol abuse. At autopsy, the extreme cardiomegaly was found, severe atherosclerosis of the anterior descending branch of left coronary artery. The posterior wall of the right atrium was thickened (cca 9 mm) in diameter of cca 3 × 3 cm, and this area was yellowish in the luminal part, while the central part was filled with dark red blood. A detailed dissection of the coronary arteries showed the complete occlusion of the atrial branch of the right coronary artery wreath as far as the place of sinoatrial artery branching, which corresponded anatomically to the described area of infarction on the posterior wall of the right atrium. Histopathological examination of the previously described area of the posterior wall of the right atrium, showed four zones of heart muscle changes: 1. zone of partially preserved structure of the heart muscle, 2. zone of cellular (immature) connective tissue, 3. areas of bleeding in cellular connective tissue, and 4. zone of acellular (old) connective tissue. These histopathological changes indicated that the posterior wall of the right atrium was affected by myocardial necrosis in at least two and possibly more times. It is reasonable to think that bleeding in the third zone of the posterior wall of the right atrium contributed greatly to the death due to the anatomical proximity to the sinoatrial node. It was confirmed by the existence of bradycardia with a prolonged PR interval, PR segment elevation in D1 and aVL lead and PR depression in the D3 lead on the ECG. These ECG changes appeared immediately before asystolia and the

  16. Radiofrequency Ablation of Persistent Atrial Fibrillation

    PubMed Central

    Hussein, Ayman A.; Saliba, Walid I.; Barakat, Amr; Bassiouny, Mohammed; Chamsi-Pasha, Mohammed; Al-Bawardy, Rasha; Hakim, Ali; Tarakji, Khaldoun; Baranowski, Bryan; Cantillon, Daniel; Dresing, Thomas; Tchou, Patrick; Martin, David O.; Varma, Niraj; Bhargava, Mandeep; Callahan, Thomas; Niebauer, Mark; Kanj, Mohamed; Chung, Mina; Natale, Andrea; Lindsay, Bruce D.; Wazni, Oussama M.

    2017-01-01

    Background Various ablation strategies of persistent atrial fibrillation (PersAF) have had disappointing outcomes, despite concerted clinical and research efforts, which could reflect progressive atrial fibrillation–related atrial remodeling. Methods and Results Two-year outcomes were assessed in 1241 consecutive patients undergoing first-time ablation of PersAF (2005–2012). The time intervals between the first diagnosis of PersAF and the ablation procedures were determined. Patients had echocardiograms and measures of B-type natriuretic peptide and C-reactive protein before the procedures. The median diagnosis-to-ablation time was 3 years (25th–75th percentiles 1–6.5). With longer diagnosis-to-ablation time (based on quartiles), there was a significant increase in recurrence rates in addition to an increase in B-type natriuretic peptide levels (P=0.01), C-reactive protein levels (P<0.0001), and left atrial size (P=0.03). The arrhythmia recurrence rates over 2 years were 33.6%, 52.6%, 57.1%, and 54.6% in the first, second, third, and fourth quartiles, respectively (Pcategorical<0.0001). In Cox Proportional Hazard analyses, B-type natriuretic peptide levels, C-reactive protein levels, and left atrial size were associated with arrhythmia recurrence. The diagnosis-to-ablation time had the strongest association with the ablation outcomes which persisted in multivariable Cox analyzes (hazard ratio for recurrence per +1Log diagnosis-to-ablation time 1.27, 95% confidence interval 1.14–1.43; P<0.0001; hazard ratio fourth versus first quartile 2.44, 95% confidence interval 1.68–3.65; Pcategorical<0.0001). Conclusions In patients with PersAF undergoing ablation, the time interval between the first diagnosis of PersAF and the catheter ablation procedure had a strong association with the ablation outcomes, such as shorter diagnosis-to-ablation times were associated with better outcomes and in direct association with markers of atrial remodeling. PMID:26763227

  17. Atrial septal defects in Florida panthers.

    PubMed

    Cunningham, M W; Dunbar, M R; Buergelt, C D; Homer, B L; Roelke-Parker, M E; Taylor, S K; King, R; Citino, S B; Glass, C

    1999-07-01

    Ostium secundum atrial septal defects (ASDs) were observed in six (3 M, 3 F) of 33 (20 M, 13 F) (18%) Florida panthers (Puma concolor coryi) necropsied by veterinary pathologists between 1985 and 1998. A seventh ASD was found in a female panther necropsied in the field and is included in the pathological description but not the prevalence of ASDs in Florida panthers. One panther (FP205) with severe ASD also had tricuspid valve dysplasia (TVD). Atrial septal defects and/or TVD are believed to have caused or contributed to the deaths of three (9%) Florida panthers in this study. Mean diameter +/- SD of ASDs was 9.0 +/- 4.7 mm (range 3 to 15 mm). Gross pathological changes attributed to ASDs/TVD in severely affected panthers (ASD > or = 10 mm) (n = 4) included mild right ventricular dilatation (n = 3) and hypertrophy (n = 2), mild to severe right atrial dilatation (n = 2), and acute pulmonary edema (n = 3). Panthers with mild ASDs (ASD < or = 5 mm) (n = 3) had no other detectable gross pathological changes associated with the ASDs. Histological examination of lungs of three panthers with severe ASDs revealed mild to moderate dilatation with fibrosis and smooth muscle atrophy of the tunica media of medium to large caliber arteries (n = 2), interstitial and/or pleural fibrosis (n = 2), perivascular fibrosis (n = 1), and acute to chronic edema (n = 3). Twenty-six necropsied panthers were examined one or more times while living; medical records were retrospectively evaluated. Antemortem radiographic, electrocardiographic, and echocardiographic examinations were performed on two panthers with severe ASDs (FP20 and FP205). Thoracic radiographic abnormalities in both included right heart enlargement, and in FP205 (severe ASD and TVD), mild pulmonary overperfusion. Electrocardiographic examination of FP205 revealed a right ventricular hypertrophy pattern, while FP205 had a normal electrocardiogram. Echocardiographic examination of FP20 revealed marked right atrial dilatation

  18. Inter-Subject Variability in Human Atrial Action Potential in Sinus Rhythm versus Chronic Atrial Fibrillation

    PubMed Central

    Sánchez, Carlos; Bueno-Orovio, Alfonso; Wettwer, Erich; Loose, Simone; Simon, Jana; Ravens, Ursula; Pueyo, Esther; Rodriguez, Blanca

    2014-01-01

    Aims 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. Methods and Results 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 GK1, GKur and Gto, consistent with AF-related remodeling as reported in experiments. In all SR and cAF model populations, inter-subject variability in IK1 and INaK underlies variability in APD90, variability in IKur, ICaL and INaK modulates variability in APD50 and combined variability in Ito and IKur determines variability in APD20. The large variability in human atrial AP triangulation is mostly determined by IK1 and either INaK or INaCa depending on the model. Conclusion 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

  19. Surviving catastrophic disintegration of a large left atrial myxoma: the importance of multi-disciplinary team.

    PubMed

    Habbab, Louay; Alfaraidi, Haifa; Lamy, Andre

    2014-09-12

    Atrial myxomas are the most common primary cardiac tumors, representing ∼50% of all benign cardiac tumors. Patients with a left atrial myxoma (LAM) generally present with symptoms of mechanical obstruction of blood flow, systemic emboli or constitutional symptoms. Embolic complications may occur any time with progression of the tumor; therefore, myxoma is usually considered an indication for urgent surgery. This report describes a patient with mobile large LAM who survived multiple emboli to the brain, spleen, kidneys, abdominal aorta and lower limbs during hospitalization for surgery, illustrating the critical nature of this finding and its possible catastrophic complications and demonstrating the importance of multi-disciplinary team in the decision-making process and the management of such complications and supporting the hypothesis that intravenous thrombolysis may be safely used in the treatment of embolic stroke due to cardiac myxoma.

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

    PubMed

    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.

  1. The role of left atrial receptors in the diuretic response to left atrial distension

    PubMed Central

    Ledsome, J. R.; Linden, R. J.

    1968-01-01

    1. The diuretic response to distension of the whole left atrium caused by obstruction of the mitral orifice has been compared with the effects of distension (by means of small balloons) of the left pulmonary vein/left atrial junctions. 2. Distension of the pulmonary vein/atrial junctions caused an increase in heart rate and a diuresis similar to but smaller than that caused by mitral obstruction. 3. Section of both ansae subclaviae prevented the increase in heart rate produced by distension of the pulmonary vein/left atrial junctions but had little effect on the diuretic response either to pulmonary vein distension or to mitral obstruction. 4. A diuretic response to mitral obstruction could be demonstrated after all nerves from the lungs had been cut but not after the vagus nerves had been cut at levels likely to interrupt the majority of afferent fibres from left atrial receptors. 5. The results support the view that stimulation of left atrial receptors is a major factor in the production of a diuretic response to mitral obstruction. PMID:5698283

  2. Energetic metabolism during acute stretch-related atrial fibrillation Shortened title: atrial fibrillation and metabolism

    PubMed Central

    Kalifa, J; Maixent, JM; Chalvidan, T; Dalmasso, C; Colin, D; Cozma, D; Laurent, P; Deharo, JC; Djiane, P; Cozzone, P; Bernard, M

    2010-01-01

    Background and methods Perturbations in energetic metabolism and impaired atrial contractility may play an important role in the pathogenesis of atrial fibrillation (AF). Besides, atrial stretch is commonly associated with AF. However, the atrial energetics of stretch-related AF are poorly understood. Here, we measured indicators of energy metabolism during acute-stretch related AF. PCr, adenine nucleotides and derivatives concentrations as well as the activity of the F0F1-ATPase and Na,K-ATPase were obtained after one hour of stretch and/or AF in isolated rabbit hearts and compared to control hearts without stretch and AF. Results After one hour of stretch-related AF, the total adenine nucleotides pool was significantly lower (42.2±2.6 versus 63.7±8.3 µmol/g protein in control group, p<0.05) and the PCr/ATP ratio significantly higher (2.3±0.3 vs 1.1± 0.1 in control group p<0.05), because of ATP, ADP and AMP decrease and PCr increase. The sum of high energy phosphate compounds did not change. There were no significant differences in F0F1-ATPase nor Na,K-ATPase activity between the groups. Conclusions Results show that in this experimental model, acute-stretch related AF induces specific modifications of atrial myocytes energetics that may play a pivotal role in the perpetuation of the arrhythmia. PMID:18553177

  3. Distinct contractile and molecular differences between two goat models of atrial dysfunction: AV block-induced atrial dilatation and atrial fibrillation.

    PubMed

    Greiser, Maura; Neuberger, Hans-Ruprecht; Harks, Erik; El-Armouche, Ali; Boknik, Peter; de Haan, Sunniva; Verheyen, Fons; Verheule, Sander; Schmitz, Wilhelm; Ravens, Ursula; Nattel, Stanley; Allessie, Maurits A; Dobrev, Dobromir; Schotten, Ulrich

    2009-03-01

    Atrial dilatation is an independent risk factor for thromboembolism in patients with and without atrial fibrillation (AF). In many patients, atrial dilatation goes along with depressed contractile function of the dilated atria. While some mechanisms causing atrial contractile dysfunction in fibrillating atria have been addressed previously, the cellular and molecular mechanisms of atrial contractile remodeling in dilated atria are unknown. This study characterized in vivo atrial contractile function in a goat model of atrial dilatation and compared it to a goat model of AF. Differences in the underlying mechanisms were elucidated by studying contractile function, electrophysiology and sarcoplasmic reticulum (SR) Ca2+ load in atrial muscle bundles and by analyzing expression and phosphorylation levels of key Ca2+-handling proteins, myofilaments and the expression and activity of their upstream regulators. In 7 chronically instrumented, awake goats atrial contractile dysfunction was monitored during 3 weeks of progressive atrial dilatation after AV-node ablation (AV block goats (AVB)). In open chest experiments atrial work index (AWI) and refractoriness were measured (10 goats with AVB, 5 goats with ten days of AF induced by repetitive atrial burst pacing (AF), 10 controls). Isometric force of contraction (FC), transmembrane action potentials (APs) and rapid cooling contractures (RCC, a measure of SR Ca2+ load) were studied in right atrial muscle bundles. Total and phosphorylated Ca2+-handling and myofilament protein levels were quantified by Western blot. In AVB goats, atrial size increased by 18% (from 26.6+/-4.4 to 31.6+/-5.5 mm, n=7 p<0.01) while atrial fractional shortening (AFS) decreased (from 18.4+/-1.7 to 12.8+/-4.0% at 400 ms, n=7, p<0.01). In open chest experiments, AWI was reduced in AVB and in AF goats compared to controls (at 400 ms: 8.4+/-0.9, n=7, and 3.2+/-1.8, n=5, vs 18.9+/-5.3 mmxmmHg, n=7, respectively, p<0.05 vs control). FC of isolated right

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

    PubMed Central

    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

  5. Atrial fibrillation in hypertrophic cardiomyopathy: mechanisms, embolic risk and prognosis.

    PubMed

    Nair, Ajith G; Fischer, Avi G

    2006-12-01

    Hypertrophic cardiomyopathy (HCM) is associated with an increased incidence of supraventricular and ventricular arrhythmias. Atrial fibrillation (AF) is the most common arrhythmia in HCM with a prevalence of 20% and an annual incidence of two percent per year. Increased left atrial size and volume along with impaired left atrial function confer an increased likelihood of AF. The onset of AF is often accompanied by a decrease in functional status in conjunction with an increased risk of stroke and overall mortality.

  6. Aorto-left atrial tunnel: a rare entity.

    PubMed

    Paul, Sajiv K; Gajjar, Trushar P; Desai, Neelam B

    2013-05-01

    Aorto-left atrial tunnel (ALAT) is a vascular channel that originates from 1 of the sinuses of Valsalva and terminates in the left atrium. The aorto-left atrial tunnel is an extremely rare anomaly. We describe here a case of congenital aorto-left atrial tunnel in a 4-year-old child who underwent successful surgical ligation with good immediate and early results.

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

    PubMed

    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

  8. Hemodynamic forces regulate developmental patterning of atrial conduction.

    PubMed

    Bressan, Michael C; Louie, Jonathan D; Mikawa, Takashi

    2014-01-01

    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.

  9. The role of myocardial wall thickness in atrial arrhythmogenesis.

    PubMed

    Whitaker, John; Rajani, Ronak; Chubb, Henry; Gabrawi, Mark; Varela, Marta; Wright, Matthew; Niederer, Steven; O'Neill, Mark D

    2016-12-01

    Changes in the structure and electrical behaviour of the left atrium are known to occur with conditions that predispose to atrial fibrillation (AF) and in response to prolonged periods of AF. We review the evidence that changes in myocardial thickness in the left atrium are an important part of this pathological remodelling process. Autopsy studies have demonstrated changes in the thickness of the atrial wall between patients with different clinical histories. Comparison of the reported tissue dimensions from pathological studies provides an indication of normal ranges for atrial wall thickness. Imaging studies, most commonly done using cardiac computed tomography, have demonstrated that these changes may be identified non-invasively. Experimental evidence using isolated tissue preparations, animal models of AF, and computer simulations proves that the three-dimensional tissue structure will be an important determinant of the electrical behaviour of atrial tissue. Accurately identifying the thickness of the atrial may have an important role in the non-invasive assessment of atrial structure. In combination with atrial tissue characterization, a comprehensive assessment of the atrial dimensions may allow prediction of atrial electrophysiological behaviour and in the future, guide radiofrequency delivery in regions based on their tissue thickness.

  10. [Atrial fibrillation concomitant with valvular heart disease].

    PubMed

    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.

  11. Effects of APD Dispersion on Atrial Reentry

    NASA Astrophysics Data System (ADS)

    Vigmond, Edward; Kuo, Samuel; Trayanova, Natalia

    2002-03-01

    Atrial fibrillation is the most common cardiac arrhythmia with dispersion of refractoriness being postulated as a mechanism promoting its formation. The distribution of action potential duration (APD) over the atria, however, remains unmapped under both normal and pathological conditions. The purpose of this computer study was to investigate how APD heterogenity interacts with morphological barriers to produce reentry. Reentries were first initiated in a 2D sheet of atrial tissue. The effects of incorporating APD heterogeneity and periodic boundary conditions, to better mimic physiological conditions, on reentry were ascertained. Analysis was extended to a morphologically realistic 3D model wherein several APD distributions were simulated. Comparisons between the 2D and 3D models demonstrated that the sheet behaviour was insufficient to capture the complex behaviour. Regional differences in APD, aided by anatomical barriers, were found to affect the formation and stabilization of reentrant circuits, as well as lead to the fractionation of wavefronts.

  12. [Atrial fibrillation ablation: application of nurse methodology].

    PubMed

    Ramos-González-Serna, Amelia; Mateos-García, M Dolores

    2011-01-01

    Ablation of pulmonary veins for treatment of atrial fibrillation involves applying radiofrequency energy wave by a catheter that causes a circumferential lesion to achieve electrical isolation and voltage drop in the interior. It is mainly applied when there is resistance to treatment and recurrence of symptoms affecting the quality of life of patients. The nurse is an important part of the multidisciplinary team who care for patients who undergo this procedure. The provision of comprehensive nursing care should include nursing procedures prior to, during, and after treatment to ensure the careful and systematic quality required. The aims of this article are: to provide specialised knowledge on the procedure of atrial fibrillation ablation, to describe the preparation of the electrophysiology laboratory, analyse nursing care and develop a standardized care plan for patients on whom this procedure is performed using the NANDA (North American Nursing Association) taxonomy and NIC (Nursing Intervention Classification).

  13. [Progress of anticoagulation therapy in atrial fibrillation].

    PubMed

    Hernández Olmedo, Miguel; Suárez Fernández, Carmen

    2015-08-07

    Atrial fibrillation is currently a very prevalent disease and it represents one of the most common causes of disabling stroke. Antithrombotic therapies have reduced the incidence of this complication although they pose many limitations and difficulties. As a result, a large number of high risk patients do not receive an appropriate treatment. In recent years, four new oral anticoagulants (NOAC) with relevant advantages in comparison to vitaminK antagonists have been released. Four large phaseiii clinical trials have demonstrated that NOAC are at least as safe and efficacious as warfarin in stroke prevention in non-valve atrial fibrillation patients with moderate-high thrombotic risk, being their main advantage the reduction in intracranial hemorrhage. The arrival of these drugs has caused great expectations in the management of these patients but also new doubts. Lacking data in some subgroups of frail patients, the absence of specific antidotes available and specially their high cost represent nowadays the main limitations for their generalization.

  14. Lipid-altering therapy and atrial fibrillation.

    PubMed

    Bachmann, Justin M; Majmudar, Maulik; Tompkins, Christine; Blumenthal, Roger S; Marine, Joseph E

    2008-01-01

    Atrial fibrillation (AF) is a common cardiac arrhythmia with significant morbidity and public health cost. Because of limitations of efficacy and safety of conventional antiarrhythmic agents, alternative therapies for AF are needed. The potential antiarrhythmic properties of lipid-altering therapy, including the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors and fish oils, are increasingly recognized, particularly in light of their potential anti-inflammatory properties. This review examines the known effects of lipid-altering therapy on atrial arrhythmias in both experimental and clinical settings. Inflammatory states, such as post-cardiac surgery and AF of recent onset, show promise as targets. In contrast, lipid-lowering therapy is less likely to affect longstanding persistent AF. Current recommendations for the use of lipid-altering therapy for prevention and treatment of AF are summarized.

  15. Control of submersible vortex flows

    NASA Technical Reports Server (NTRS)

    Bushnell, D. M.; Donaldson, C. D.

    1990-01-01

    Vortex flows produced by submersibles typically unfavorably influence key figures of merit such as acoustic and nonacoustic stealth, control effectiveness/maneuverability, and propulsor efficiency/body drag. Sources of such organized, primarily longitudinal, vorticity include the basic body (nose and sides) and appendages (both base/intersection and tip regions) such as the fairwater, dive planes, rear control surfaces, and propulsor stators/tips. Two fundamentally different vortex control approaches are available: (1) deintensification of the amplitude and/or organization of the vortex during its initiation process; and (2) downstream vortex disablement. Vortex control techniques applicable to the initiation region (deintensification approach) include transverse pressure gradient minimization via altered body cross section, appendage dillets, fillets, and sweep, and various appendage tip and spanload treatment along with the use of active controls to minimize control surface size and motions. Vortex disablement can be accomplished either via use of control vortices (which can also be used to steer the vortices off-board), direct unwinding, inducement of vortex bursting, or segmentation/tailoring for enhanced dissipation. Submersible-applicable vortex control technology is also included derived from various aeronautical applications such as mitigation of the wing wake vortex hazard and flight aircraft maneuverability at high angle of attack as well as the status of vortex effects upon, and mitigation of, nonlinear control forces on submersibles. Specific suggestions for submersible-applicable vortex control techniques are presented.

  16. Sequential Hybrid Procedure for Persistent Atrial Fibrillation

    PubMed Central

    Bulava, Alan; Mokracek, Ales; Hanis, Jiri; Kurfirst, Vojtech; Eisenberger, Martin; Pesl, Ladislav

    2015-01-01

    Background Catheter ablation of persistent atrial fibrillation yields an unsatisfactorily high number of failures. The hybrid approach has recently emerged as a technique that overcomes the limitations of both surgical and catheter procedures alone. Methods and Results We investigated the sequential (staged) hybrid method, which consists of a surgical thoracoscopic radiofrequency ablation procedure followed by radiofrequency catheter ablation 6 to 8 weeks later using the CARTO 3 mapping system. Fifty consecutive patients (mean age 62±7 years, 32 males) with long‐standing persistent atrial fibrillation (41±34 months) and a dilated left atrium (>45 mm) were included and prospectively followed in an unblinded registry. During the electrophysiological part of the study, all 4 pulmonary veins were found to be isolated in 36 (72%) patients and a complete box‐lesion was confirmed in 14 (28%) patients. All gaps were successfully re‐ablated. Twelve months after the completed hybrid ablation, 47 patients (94%) were in normal sinus rhythm (4 patients with paroxysmal atrial fibrillation required propafenone and 1 patient underwent a redo catheter procedure). The majority of arrhythmias recurred during the first 3 months. Beyond 12 months, there were no arrhythmia recurrences detected. The surgical part of the procedure was complicated by 7 (13.7%) major complications, while no serious adverse events were recorded during the radiofrequency catheter part of the procedure. Conclusions The staged hybrid epicardial–endocardial treatment of long‐standing persistent atrial fibrillation seems to be extremely effective in maintenance of normal sinus rhythm compared to radiofrequency catheter or surgical ablation alone. Epicardial ablation alone cannot guarantee durable transmural lesions. Clinical Trial Registration URL: www.ablace.cz Unique identifier: cz‐060520121617 PMID:25809548

  17. Atrial Fibrillation During an Exploration Class Mission

    NASA Technical Reports Server (NTRS)

    Lipset, Mark A.; Lemery, Jay; Polk, J. D.; Hamilton, Douglas R.

    2010-01-01

    Background: A long-duration exploration class mission is fraught with numerous medical contingency plans. Herein, we explore the challenges of symptomatic atrial fibrillation (AF) occurring during an exploration class mission. The actions and resources required to ameliorate the situation, including the availability of appropriate pharmaceuticals, monitoring devices, treatment modalities, and communication protocols will be investigated. Challenges of Atrial Fibrillation during an Exploration Mission: Numerous etiologies are responsible for the initiation of AF. On Earth, we have the time and medical resources to evaluate and determine the causative situation for most cases of AF and initiate therapy accordingly. During a long-duration exploration class mission resources will be severely restricted. How is one to determine if new onset AF is due to recent myocardial infarction, pulmonary embolism, fluid overload, thyrotoxicosis, cardiac structural abnormalities, or CO poisoning? Which pharmaceutical therapy should be initiated and what potential side effects can be expected? Should anti-coagulation therapy be initiated? How would one monitor the therapeutic treatment of AF in microgravity? What training would medical officers require, and which communication strategies should be developed to enable the best, safest therapeutic options for treatment of AF during a long-duration exploration class mission? Summary: These questions will be investigated with expert opinion on disease elucidation, efficient pharmacology, therapeutic monitoring, telecommunication strategies, and mission cost parameters with emphasis on atrial fibrillation being just one illustration of the tremendous challenges that face a long-duration exploration mission. The limited crew training time, medical hardware, and drugs manifested to deal with such an event predicate that aggressive primary and secondary prevention strategies be developed to protect a multibillion-dollar asset like the

  18. Atrial Fibrillation - Multiple Languages: MedlinePlus

    MedlinePlus

    ... sharing features on this page, please enable JavaScript. Arabic (العربية) Chinese - Simplified (简体中文) Chinese - Traditional (繁體中文) French ( ... Somali (af Soomaali) Spanish (español) Vietnamese (Tiếng Việt) Arabic (العربية) Atrial Fibrillation (Arabic) العربية Bilingual PDF Health ...

  19. [Non-pharmacologic treatment of atrial fibrillation].

    PubMed

    Csanádi, Zoltán; Fazekas, Tamás; Varró, András

    2003-06-29

    The authors provide an update on non-pharmacological treatment of atrial fibrillation (AF). They emphasize that although antiarrhythmic drugs continue to be first-line therapy for the arrhythmia considered to be a cardiovascular epidemic, clinical research to develop non-pharmacological means of treatment has been unprecedentally intensified during the last decade. Electrical cardioversion is the most successful non-pharmacological method to restore sinus rhythm, also the efficacy and safety of AV node ablation for palliative ventricular rate-controll is established. "Hybrid" therapeutic procedures, involving combinations of pharmacological and non-pharmacological interventions have gained widespread use. Curative transcatheter ablation for arrhythmia prevention is to be considered in case of clinical suggestions that AF is initiated by a primary regular arrhythmia that is amenable to routine catheter ablation (secondary AF). Despite encouraging results, at this point in time, curative catheter ablation for primary AF may offer significant improvement or even cure only for a small subset of patients, mostly young individuals with normal heart, and paroxysmal AF with frequent, symptomatic episodes refractory to multiple antiarrhythmic drugs. These interventions are to be performed in the settings of a clinical research project in some institutions. Regarding pacemaker therapy in case of bradycardia indication, physiologic pacing (AAI or DDD) is associated with significantly lower incidence of atrial fibrillation than ventricular pacing. Large-scale randomized controlled trials are needed to assess the clinical value of specially designed implantable devices to prevent atrial fibrillation in patients with no conventional bradycardia indication. Also, technical optimization and proper clinical evaluation is needed for implantable atrioverters and implantable cardioverter defibrillators capable of atrial cardioversion therapy.

  20. Predictive value of various Doppler-derived parameters of atrial conduction time for successful atrial fibrillation ablation

    PubMed Central

    Valtuille, Lucas; Choy, Jonathan B; Becher, Harald

    2015-01-01

    Various Doppler-derived parameters of left atrial electrical remodeling have been demonstrated to predict recurrence of atrial fibrillation (AF) after AF ablation. The aim of this study was to compare three Doppler-derived measures of atrial conduction time in patients undergoing AF ablation, and to investigate their predictive value for successful procedure. In 32 prospectively enrolled patients undergoing the first AF ablation, atrial conduction time was estimated by measuring the time delay between the onset of P-wave on the surface ECG to the peak of the a′-wave on the pulsed-wave Doppler and color-coded tissue Doppler imaging of the left atrial lateral wall, and to the peak of the A-wave on the pulsed-wave Doppler of the mitral inflow. There was a significant difference in the baseline atrial conduction time measured by different echocardiographic techniques. Most (88%) patients had normal or only mildly dilated left atrium. At 6 months, 12 patients (38%) had recurrent AF/atrial tachycardia. The duration of history of AF was the only predictor of AF/atrial tachycardia recurrence following the first AF ablation (P=0.024; OR 1.023, CI 1.003–1.044). A combination of normal left atrial volume and history of paroxysmal AF of ≤48 months was associated with the best outcome. Predictive value of the Doppler derived parameters of atrial conduction time may be reduced in the early stages of left atrial remodeling. Future studies may determine which echocardiographic parameter correlates best with the extent of left atrial remodeling and is most predictive of successful AF ablation. PMID:26795694

  1. Atrial fibrillation in obstructive sleep apnea

    PubMed Central

    Goyal, Sandeep K; Sharma, Abhishek

    2013-01-01

    Atrial fibrillation (AF) is a common arrhythmia with rising incidence. Obstructive sleep apnea (OSA) is prevalent among patients with AF. This observation has prompted significant research in understanding the relationship between OSA and AF. Multiple studies support a role of OSA in the initiation and progression of AF. This association has been independent of obesity, body mass index and hypertension. Instability of autonomic tone and wide swings in intrathoracic pressure are seen in OSA. These have been mechanistically linked to initiation of AF in OSA patients by lowering atrial effective refractory period, promoting pulmonary vein discharges and atrial dilation. OSA not only promotes initiation of AF but also makes management of AF difficult. Drug therapy and electrical cardioversion for AF are less successful in presence of OSA. There has been higher rate of early and overall recurrence after catheter ablation of AF in patients with OSA. Treatment of OSA with continuous positive airway pressure has been shown to improve control of AF. However, additional studies are needed to establish a stronger relationship between OSA treatment and success of AF therapies. There should be heightened suspicion of OSA in patients with AF. There is a need for guidelines to screen for OSA as a part of AF management. PMID:23802045

  2. Right atrial thrombi: Percutaneous mechanical thrombectomy

    SciTech Connect

    Beregi, Jean-Paul; Aumegeat, Valerie; Loubeyre, Christophe; Coullet, Jean-Michel; Asseman, Philippe; Debacker-Steckelorom, Caroline; Bauchart, Jean-Jacques; Liu Pengcheng; Thery, Claude

    1997-03-15

    The current therapeutic options for right atrial thrombi-surgical embolectomy and thrombolysis- are associated with high mortality and such patients often have contraindications to these therapeutic options. the purpose of this study was to evaluate the feasibility of endovascular right atrial embolectomy. Two patients with contraindications to thrombolysis and surgery were treated by a femoral approach. A catheter was placed in the right atrium, under fluoroscopic control, and a basket device was used to trap the thrombus. The location and extent of the thrombus was established before the procedure by transesophageal echocardiography (TEE) and the procedure was performed with TEE and fluoroscopy. Thrombi were withdrawn in the basket into the inferior vena cava (IVC) and a filter was inserted by a jugular approach and positioned in the IVC, just above the thrombi. The basket was removed leaving the thrombus below the filter. One patient died immediately after the procedure. In conclusion, endovascular extraction of right atrial thrombi may represent a potential therapeutic alternative, particularly in patients with contraindications to thrombolysis and surgery.

  3. Atrial fibrillation: effects beyond the atrium?

    PubMed

    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.

  4. Dronedarone in the management of atrial fibrillation

    PubMed Central

    Saleem, TS Mohamed; Bharani, K; Chetty, C Madhusudhana; Gauthaman, K

    2010-01-01

    Atrial fibrillation is the most common type of tachyarrhythmia caused by multiple re-entrant wave forms within the atria and bombarding the atrioventricular node several times making it beat in a rapid, disorganized fashion termed “fibrillation”. In atrial fibrillation, atria beat more than 300 times per minute. The arrhythmatous condition needs to be controlled, as humans cannot withstand this rapid and chaotic beating of the heart. New investigational drugs like Dronedarone® are being used. Dronedarone is the most recent antiarrhythmic drugs. It was approved by US-FDA on July 2nd 2009 and is available in the USA as Multaq tablets (400 mg). Dronedarone falls under the category of multiple ion channel blocker. It mainly targets the repolarization currents, making them less active and hence prolonging the action potential duration (APD). Dronedarone also exhibits antiadrenergic activity, thus reducing the pace of the pacemaker. Dronedarone has been proven to be a safer and efficacious AAD, evidenced by both animal and human studies. These studies showed that there was prolongation of the APD and absence of QT interval prolongation with long term administration of the drug. Also there was reduced thyroid hormone receptor expression. Dronedarone is significantly safer and effective in maintaining the sinus rhythm and reducing the ventricular proarrhythmias, justifying it for the long term treatment of atrial fibrillation compared to other antiarrhythmic drugs. PMID:27147833

  5. Benchmarking electrophysiological models of human atrial myocytes

    PubMed Central

    Wilhelms, Mathias; Hettmann, Hanne; Maleckar, Mary M.; Koivumäki, Jussi T.; Dössel, Olaf; Seemann, Gunnar

    2013-01-01

    Mathematical modeling of cardiac electrophysiology is an insightful method to investigate the underlying mechanisms responsible for arrhythmias such as atrial fibrillation (AF). In past years, five models of human atrial electrophysiology with different formulations of ionic currents, and consequently diverging properties, have been published. The aim of this work is to give an overview of strengths and weaknesses of these models depending on the purpose and the general requirements of simulations. Therefore, these models were systematically benchmarked with respect to general mathematical properties and their ability to reproduce certain electrophysiological phenomena, such as action potential (AP) alternans. To assess the models' ability to replicate modified properties of human myocytes and tissue in cardiac disease, electrical remodeling in chronic atrial fibrillation (cAF) was chosen as test case. The healthy and remodeled model variants were compared with experimental results in single-cell, 1D and 2D tissue simulations to investigate AP and restitution properties, as well as the initiation of reentrant circuits. PMID:23316167

  6. [Pharmacological rate control therapy for atrial fibrillation].

    PubMed

    Ishikawa, Toshiyuki

    2013-01-01

    Many studies have reported that there is no significant difference in survival rate between rhythm control and rate control strategies in combination of with anticoagulation in patients with atrial fibrillation. Even in patients with atrial fibrillation and with heart failure there is no significant difference in survival rate between both strategies. There is no need of strict rate control. In patients with permanent atrial fibrillation, lemient rate control(resting heart rate of below 110 beats per minute) is as effective as strict rate control (< 70 beats per minute) and easier to achieve. Digitalis, beta-blockers and Ca channel blockers are used for rate control treatments. Digitalis is the only drug that has both decreasing ventricular response by suppressing atrioventricular conduction and inotropic effects. However, digitalis can not suppress heart rates during exercise. Beta-blockers and Ca channel blockers can suppress heart rates not only at rest but also during exercise. Ca channel blockers can not be used for patients with heart failure due to reduction in contractility of heart muscle. It has been reported that cardiac function and survival rate can be improved by beta-blockers in patients with heart failure if starting low dose and increasing gradually.

  7. Atrial Fibrillation: The Science behind Its Defiance

    PubMed Central

    Czick, Maureen E.; Shapter, Christine L.; Silverman, David I.

    2016-01-01

    Atrial fibrillation (AF) is the most prevalent arrhythmia in the world, due both to its tenacious treatment resistance, and to the tremendous number of risk factors that set the stage for the atria to fibrillate. Cardiopulmonary, behavioral, and psychological risk factors generate electrical and structural alterations of the atria that promote reentry and wavebreak. These culminate in fibrillation once atrial ectopic beats set the arrhythmia process in motion. There is growing evidence that chronic stress can physically alter the emotion centers of the limbic system, changing their input to the hypothalamic-limbic-autonomic network that regulates autonomic outflow. This leads to imbalance of the parasympathetic and sympathetic nervous systems, most often in favor of sympathetic overactivation. Autonomic imbalance acts as a driving force behind the atrial ectopy and reentry that promote AF. Careful study of AF pathophysiology can illuminate the means that enable AF to elude both pharmacological control and surgical cure, by revealing ways in which antiarrhythmic drugs and surgical and ablation procedures may paradoxically promote fibrillation. Understanding AF pathophysiology can also help clarify the mechanisms by which emerging modalities aiming to correct autonomic imbalance, such as renal sympathetic denervation, may offer potential to better control this arrhythmia. Finally, growing evidence supports lifestyle modification approaches as adjuncts to improve AF control. PMID:27699086

  8. Animal studies of epicardial atrial ablation.

    PubMed

    Schuessler, Richard B; Lee, Anson M; Melby, Spencer J; Voeller, Rochus K; Gaynor, Sydney L; Sakamoto, Shun-Ichiro; Damiano, Ralph J

    2009-12-01

    The Cox maze procedure is an effective treatment of atrial fibrillation, with a long-term freedom from recurrence greater than 90%. The original procedure was highly invasive and required cardiopulmonary bypass. Modifications of the procedure that eliminate the need for cardiopulmonary bypass have been proposed, including use of alternative energy sources to replace cut-and-sew lesions with lines of ablation made from the epicardium on the beating heart. This has been challenging because atrial wall muscle thickness is extremely variable, and the muscle can be covered with an epicardial layer of fat. Moreover, the circulating intracavitary blood acts as a potential heat sink, making transmural lesions difficult to obtain. In this report, we summarize the use of nine different unidirectional devices (four radiofrequency, two microwave, two lasers, one cryothermic) for creating continuous transmural lines of ablation from the atrial epicardium in a porcine model. We define a unidirectional device as one in which all the energy is applied by a single transducer on a single heart surface. The maximum penetration of any device was 8.3 mm. All devices except one, the AtriCure Isolator pen, failed to penetrate 2 mm in some nontransmural sections. Future development of unidirectional energy sources should be directed at increasing the maximum depth and the consistency of penetration.

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

    PubMed Central

    Smorodinova, Natalia; Bláha, Martin; Melenovský, Vojtěch; Rozsívalová, Karolína; Přidal, Jaromír; Ďurišová, Mária; Pirk, Jan; Kautzner, Josef; Kučera, Tomáš

    2017-01-01

    Background 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. Objective 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). Methods 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. Results 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. Conclusions 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. PMID:28225836

  10. Neuronally released vasoactive intestinal polypeptide alters atrial electrophysiological properties and may promote atrial fibrillation

    PubMed Central

    Xi, Yutao; Chao, Zhi-Yang James; Yan, Wen; Abbasi, Shahrzad; Yin, Xiaomeng; Mathuria, Nilesh; Patel, Mehul; Fan, Christopher; Sun, Junping; Wu, Geru; Wang, Suwei; Elayda, MacArthur; Gao, Lianjun; Wehrens, Xander H.T.; Lin, Shien-Fong; Cheng, Jie

    2015-01-01

    BACKGROUND Vagal hyperactivity promotes atrial fibrillation (AF), which has been almost exclusively attributed to acetylcholine. Vasoactive intestinal polypeptide (VIP) and acetylcholine are neurotransmitters co-released during vagal stimulation. Exogenous VIP has been shown to promote AF by shortening action potential duration (APD), increasing APD spatial heterogeneity, and causing intra-atrial conduction block. OBJECTIVE The purpose of this study was to investigate the effects of neuronally released VIP on atrial electrophysiologic properties during vagal stimulation. METHODS We used a specific VIP antagonist (H9935) to uncover the effects of endogenous VIP released during vagal stimulation in canine hearts. RESULTS H9935 significantly attenuated (1) the vagally induced shortening of atrial effective refractory period and widening of atrial vulnerability window during stimulation of cervical vagosym-pathetic trunks (VCNS) and (2) vagal effects on APD during stimulation through fat-pad ganglion plexus (VGPS). Atropine completely abolished these vagal effects during VCNS and VGPS. In contrast, VGPS-induced slowing of local conduction velocity was completely abolished by either VIP antagonist or atropine. In pacing-induced AF during VGPS, maximal dominant frequencies and their spatial gradients were reduced significantly by H9935 and, more pronouncedly, by atropine. Furthermore, VIP release in the atria during vagal stimulation was inhibited by atropine, which may account for the concealment of VIP effects with muscarinic blockade. CONCLUSION Neuronally released VIP contributes to vagal effects on atrial electrophysiologic properties and affects the pathophysiology of vagally induced AF. Neuronal release of VIP in the atria is inhibited by muscarinic blockade, a novel mechanism by which VIP effects are concealed by atropine during vagal stimulation. PMID:25748673

  11. Atrial Tachycardias after Atrial Fibrillation Ablation Manifest Different Waveform Characteristics: Implications for Characterizing Tachycardias

    PubMed Central

    Biviano, Angelo B.; Ciaccio, Edward J.; Fleitman, Jessica; Knotts, Robert; Lawrence, John; Haynes, Norrisa; Cyrille, Nicole; Hickey, Kathleen; Iyer, Vivek; Wan, Elaine; Whang, William; Garan, Hasan

    2015-01-01

    INTRODUCTON Atrial fibrillation (AF) ablation patients often manifest atrial tachycardias (AT) with atypical ECG morphologies that preclude accurate localization and mechanism. Diagnostic maneuvers used to define ATs during electrophysiology studies can be limited by tachycardia termination or transformation. Additional methods of characterizing post-AF ablation ATs are required. METHODS AND RESULTS We evaluated the utility of noninvasive ECG signal analytics in post-ablation AF patients for the following features: 1) Localization of ATs (i.e., right versus left atrium), and 2) Identification of common left AT mechanisms (i.e., focal vs. macroreentrant). Atrial waveforms from the surface ECG were used to analyze: 1) Spectral organization, including dominant amplitude (DA) and mean spectral profile (MP), and 2) Temporospatial variability, using temporospatial correlation coefficients. We studied 94 ATs in 71 patients who had undergone prior pulmonary vein isolation for AF and returned for a second ablation: 1) right atrial cavotricuspid-isthmus dependent (CTI) ATs (n=21); 2) left atrial macroreentrant ATs (n=41) and focal ATs (n=32). Right CTI ATs manifested higher DAs and lower MPs than left ATs, indicative of greater stability and less complexity in the frequency spectrum. Left macroreentrant ATs possessed higher temporospatial organization than left focal ATs. CONCLUSIONS Noninvasively recorded atrial waveform signal analyses show that right ATs possess more stable activation properties than left ATs, and left macroreentrant ATs manifest higher temporospatial organization than left focal ATs. Further prospective analyses evaluating the role these novel ECG-derived tools can play to help localize and identify mechanisms of common ATs in AF ablation patients are warranted. PMID:26228873

  12. Atrial Heterogeneity Generates Re-entrant Substrate during Atrial Fibrillation and Anti-arrhythmic Drug Action: Mechanistic Insights from Canine Atrial Models

    PubMed Central

    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

  13. Transcatheter closure of tortuous aorto-right atrial fistula.

    PubMed

    Ece, Ibrahim; Uner, Abdurrahman; Cuce, Ferhat; Sahin, Musa

    2015-04-01

    Congenital fistula between the aorta and right atrium is a rare congenital anomaly of the heart. We report a new case of this unusual communication, which was successfully closed by transcatheter embolisation using an Amplatzer duct occluder II. A 7-year-old asymptomatic girl was referred to our institute for evaluation of a murmur. Echocardiography revealed intact septae and the right coronary sinus was dilated with a fistulous tract arising from the sinus and opening into the right atrium with continuous flow into the right atrium. Computerized tomography confirmed the diagnosis and delineated the anatomy. Cardiac catheterization performed confirmed the presence of a markedly tortuous and dilated aorto-right atrial fistula. Coronary angiography demonstrated normal coronary arteries arising from the respective sinuses. The fistula was closed antegradely using an Amplatzer duct occluder II (AGA Medical Corporation, Plymouth, MN, USA). The continuous murmur had disappeared after the procedure and an echocardiogram revealed no continuous flow across the fistulous tract. The patient remained well at follow-up 3 months later.

  14. Effect of whiskey on atrial vulnerability and "holiday heart".

    PubMed

    Engel, T R; Luck, J C

    1983-03-01

    Vulnerability to atrial fibrillation and flutter was examined in 11 alcohol abusers who did not have cardiomyopathy or manifest heart failure. Atrial extrastimulation was done with rapid pacing (drive cycle length 500 ms) to facilitate induction of atrial vulnerability, seen in four alcohol abusers. The remaining seven were retested 30 minutes after drinking 60 to 120 ml of 86 proof whiskey (ethanol blood levels were 49 to 101 mg/100 ml but pulmonary capillary wedge pressure remained normal in all) and atrial fibrillation or flutter was induced in three of the drinkers. Three nondrinkers, symptomatic with sinus bradycardia but not in heart failure, were found not to be vulnerable to atrial fibrillation or flutter, but flutter was induced in two of the three after drinking whiskey. Whiskey did not alter atrial functional refractory periods (mean +/- standard error of the mean 297 +/- 14 to 290 +/- 12 ms) or widen the dispersion among three disparate right atrial sites (57 +/- 13 to 47 +/- 12 ms). Thus, whiskey enhanced vulnerability to atrial fibrillation and flutter in patients without heart failure or cardiomyopathy, substantiating the "holiday heart" syndrome.

  15. Atrial Arrhythmias and Their Implications for Space Flight - Introduction

    NASA Technical Reports Server (NTRS)

    Polk, J. D.; Barr, Y. R.; Bauer, P.; Hamilton, D. R.; Kerstman, E.; Tarver, B.

    2010-01-01

    This panel will discuss the implications of atrial arrhythmias in astronauts from a variety of perspectives; including historical data, current practices, and future challenges for exploration class missions. The panelists will present case histories, outline the evolution of current NASA medical standards for atrial arrhythmias, discuss the use of predictive tools, and consider potential challenges for current and future missions.

  16. Atrial rate and rhythm abnormalities in a patient with hyperkalemia.

    PubMed

    Rosman, Jonathan; Thiagarajah, Prashan; Schweitzer, Paul; Rachko, Maurice; Hanon, Sam

    2009-05-15

    A 67 year old man presented with a serum potassium of 7.7 mEq/L and slow atrial flutter with variable A-V block and peaked T waves. Initial treatment for hyperkalemia was followed by an increase in the atrial flutter rate to 300 beats per minute. After hemodialysis the rhythm converted to sinus.

  17. Atrial myxoma: a rare cause of ischemic stroke.

    PubMed

    Negi, R C; Chauhan, Vivek; Sharma, Brij; Bhardwaj, Rajeev; Thakur, Surinder

    2013-04-01

    Arial myxoma can present as stroke and should be considered as a differential diagnosis of stroke in young individuals. We present here a 42 years female who presented with sudden loss of conciousness. After extensive work up for young stroke, left atrial myxoma was detected and tumor was removed surgically and histopathological report was consistent with the atrial myxoma.

  18. Dynamics of Focal Fibrillation Waves during Persistent Atrial Fibrillation.

    PubMed

    Lanters, Eva A H; Allessie, Maurits A; DE Groot, Natasja M S

    2016-04-01

    The incidence and appearance of focal fibrillation waves on the right and left atrial epicardial surface were visualized during 10 seconds of persistent atrial fibrillation in a 71-year-old woman with valvular heart disease. The frequent, nonrepetitive, widespread, and capricious distribution of focal waves suggests that transmural conduction of fibrillation waves is most likely the mechanism underlying focal fibrillation waves.

  19. Atrial metabolism and tissue perfusion as determinants of electrical and structural remodelling in atrial fibrillation.

    PubMed

    Opacic, Dragan; van Bragt, Kelly A; Nasrallah, Hussein M; Schotten, Ulrich; Verheule, Sander

    2016-04-01

    Atrial fibrillation (AF) is the most common tachyarrhythmia in clinical practice. Over decades of research, a vast amount of knowledge has been gathered about the causes and consequences of AF related to cellular electrophysiology and features of the tissue structure that influence the propagation of fibrillation waves. Far less is known about the role of myocyte metabolism and tissue perfusion in the pathogenesis of AF. However, the rapid rates of electrical activity and contraction during AF must present an enormous challenge to the energy balance of atrial myocytes. This challenge can be met by scaling back energy demand and by increasing energy supply, and there are several indications that both phenomena occur as a result of AF. Still, there is ample evidence that these adaptations fall short of redressing this imbalance, which may represent a driving force for atrial electrical as well as structural remodelling. In addition, several 'metabolic diseases' such as diabetes, obesity, and abnormal thyroid function precipitate some well-known 'culprits' of the AF substrate such as myocyte hypertrophy and fibrosis, while some other AF risk factors, such as heart failure, affect atrial metabolism. This review provides an overview of metabolic and vascular alterations in AF and their involvement in its pathogenesis.

  20. [Recurrent right atrial thrombus in a patient with atrial fibrillation and heart failure].

    PubMed

    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.

  1. Atrial fibrillation and gastroesophageal reflux disease: From the cardiologist perspective.

    PubMed

    Floria, Mariana; Drug, Vasile Liviu

    2015-03-14

    We have read with interest the paper by Roman C. and colleagues discussing the relationship between gastroesophageal reflux disease and atrial fibrillation. The review is presenting the available evidence for the common pathogenic mechanisms. However, from a cardiologist perspective, some available data were not highlighted in the review, cardiovascular involvement in gastroesophageal reflux is less assessed. Hypertension, obesity or diabetes mellitus are substrate for left atrial remodeling that initiate and sustained atrial fibrillation development. One of the pathophysiologic mechanisms in atrial fibrillation is the presence of a trigger. Gastroesophageal reflux could be only a trigger for this arrhythmia. We believe that atrial fibrillation should be considered as possible extraesophageal syndrome in the gastroesophageal reflux classification.

  2. Atrial Arrhythmias in Astronauts. Summary of a NASA Summit

    NASA Technical Reports Server (NTRS)

    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.

  3. Blood pressure control versus atrial fibrillation management in stroke prevention.

    PubMed

    Savoia, Carmine; Sada, Lidia; Volpe, Massimo

    2015-06-01

    Hypertension is one of the major risk factors for atrial fibrillation which in turn is the most prevalent concomitant condition in hypertensive patients. While both these pathological conditions are independent risk factors for stroke, the association of hypertension and atrial fibrillation increases the incidence of disabling strokes. Moreover, documented or silent atrial fibrillation doubles the rate of cardiovascular death. Lowering blood pressure is strongly recommended, particularly for primary stroke prevention. However, a relatively small percentage of hypertensive patients still achieve the recommended blood pressure goals. The management of atrial fibrillation with respect to stroke prevention is changing. New oral anticoagulants represent a major advancement in long-term anticoagulation therapy in non valvular atrial fibrillation. They have several benefits over warfarin, including improved adherence to the anticoagulation therapy. This is an important issue since non-adherence to stroke prevention medications is a risk factor for first and recurrent strokes.

  4. [Effect of 3-oxypyridine and succinic acid derivatives on clinical manifestations of inflammatory diseases of the uterus and its appendages].

    PubMed

    Volchegorskiĭ, I A; Pravdin, E V; Uzlova, T V

    2013-01-01

    Two-week-long, prospective, placebo-controlled, single-blind randomized study of the effects of intravenous emoxipin (150 mg daily), reamberin (400 ml daily) and mexidol (300 mg daily) infusion on the dynamics of clinical symptoms of non-complicated recrudescence of inflammatory diseases of the uterus and its appendages (IDUA) in comparison to the standard therapy was performed. It was established that emoxipin, reamberin and mexidol administration appreciably improved the clinical state dynamics of women with recrudescence of IDUA. The effect was associated with more pronounced decrease in severity of genital and abdominal symptoms versus standard therapy results.

  5. Disturbed Left Atrial Function is Associated with Paroxysmal Atrial Fibrillation in Hypertension

    PubMed Central

    Tenekecioglu, Erhan; Agca, Fahriye Vatansever; Ozluk, Ozlem Arican; Karaagac, Kemal; Demir, Serafettin; Peker, Tezcan; Kuzeytemiz, Mustafa; Senturk, Muhammed; Yılmaz, Mustafa

    2014-01-01

    Background Hypertension is the most prevalent and modifiable risk factor for atrial fibrillation. The pressure overload in the left atrium induces pathophysiological changes leading to alterations in contractile function and electrical properties. Objective In this study our aim was to assess left atrial function in hypertensive patients to determine the association between left atrial function with paroxysmal atrial fibrillation (PAF). Method We studied 57 hypertensive patients (age: 53±4 years; left ventricular ejection fraction: 76±6.7%), including 30 consecutive patients with PAF and 30 age-matched control subjects. Left atrial (LA) volumes were measured using the modified Simpson's biplane method. Three types of LA volume were determined: maximal LA(LAVmax), preatrial contraction LA(LAVpreA) and minimal LA volume(LAVmin). LA emptying functions were calculated. LA total emptying volume = LAVmax−LAVmin and the LA total EF = (LAVmax-LAVmin )/LAVmax, LA passive emptying volume = LAVmax− LAVpreA and the LA passive EF = (LAVmax-LAVpreA)/LAVmax, LA active emptying volume = LAVpreA−LAVmin and LA active EF = (LAVpreA-LAVmin )/LAVpreA. Results The hypertensive period is longer in hypertensive group with PAF. LAVmax significantly increased in hypertensive group with PAF when compared to hypertensive group without PAF (p=0.010). LAAEF was significantly decreased in hypertensive group with PAF as compared to hypertensive group without PAF (p=0.020). A' was decreased in the hypertensive group with PAF when compared to those without PAF (p = 0.044). Conclusion Increased LA volume and impaired LA active emptying function was associated with PAF in untreated hypertensive patients. Longer hypertensive period is associated with PAF. PMID:24676227

  6. Disrupted Calcium Release as a Mechanism for Atrial Alternans Associated with Human Atrial Fibrillation

    PubMed Central

    Chang, Kelly C.; Bayer, Jason D.; Trayanova, Natalia A.

    2014-01-01

    Atrial fibrillation (AF) is the most common cardiac arrhythmia, but our knowledge of the arrhythmogenic substrate is incomplete. Alternans, the beat-to-beat alternation in the shape of cardiac electrical signals, typically occurs at fast heart rates and leads to arrhythmia. However, atrial alternans have been observed at slower pacing rates in AF patients than in controls, suggesting that increased vulnerability to arrhythmia in AF patients may be due to the proarrythmic influence of alternans at these slower rates. As such, alternans may present a useful therapeutic target for the treatment and prevention of AF, but the mechanism underlying alternans occurrence in AF patients at heart rates near rest is unknown. The goal of this study was to determine how cellular changes that occur in human AF affect the appearance of alternans at heart rates near rest. To achieve this, we developed a computational model of human atrial tissue incorporating electrophysiological remodeling associated with chronic AF (cAF) and performed parameter sensitivity analysis of ionic model parameters to determine which cellular changes led to alternans. Of the 20 parameters tested, only decreasing the ryanodine receptor (RyR) inactivation rate constant (kiCa) produced action potential duration (APD) alternans seen clinically at slower pacing rates. Using single-cell clamps of voltage, fluxes, and state variables, we determined that alternans onset was Ca2+-driven rather than voltage-driven and occurred as a result of decreased RyR inactivation which led to increased steepness of the sarcoplasmic reticulum (SR) Ca2+ release slope. Iterated map analysis revealed that because SR Ca2+ uptake efficiency was much higher in control atrial cells than in cAF cells, drastic reductions in kiCa were required to produce alternans at comparable pacing rates in control atrial cells. These findings suggest that RyR kinetics may play a critical role in altered Ca2+ homeostasis which drives proarrhythmic

  7. Prevalence of left atrial abnormalities in atrial fibrillation versus normal sinus patients

    PubMed Central

    Ketai, Loren H; Teague, Shawn D; Rissing, Stacy M

    2016-01-01

    Background Atrial fibrillation (AF) may be the cause or sequela of left atrial abnormalities and variants. Purpose To determine the prevalence of left atrial (LA) abnormalities in AF patients compared to normal sinus rhythm (NSR) patients. Material and Methods We retrospectively reviewed 281 cardiac CT examinations from 2010 to 2012, excluding patients with prior pulmonary vein ablation, known coronary artery disease, prior coronary stent placement, or coronary artery bypass grafts. The first group consisted of 159 AF patients undergoing cardiac CT prior to pulmonary vein ablation and the second group consisted of 122 NSR patients evaluated with coronary CT angiography. Demographic data were collected. LA abnormalities were analyzed. Left atrial diameter was measured on an axial view. Results A total of 281 patients were included. The male gender has significantly higher prevalence of AF than female gender, P value <0.001. Patients with AF were significantly older (mean age, 57.4 years; standard deviation [SD], 11.8 years) than NSR patients (mean age, 53.4 years; SD, 13.6 years), P value, 0.01. The left atrial diameter was greater in the AF patients (mean diameter, 4.3 cm; SD, 0.82 cm) versus the NSR patients (3.4 cm; SD, 0.58 cm), P value, <0.0001. LA diverticulum was the most prevalent variant, occurring in 28.4% of the entire patient population followed by LA pouch, occurring in 24%. There was no significant between group differences in the prevalence of these or the remainder of the LA variants. Conclusion AF patients differed significantly from NSR patients in LA size, gender, and mean age. There was no statistical significance between the two groups with regard to the LA morphologic abnormalities other than size. PMID:27358747

  8. Flow Over a Model Submarine

    NASA Astrophysics Data System (ADS)

    Jiménez, Juan; Smits, Alexander

    2003-11-01

    Experimental investigation over a DARPA SUBOFF submarine model (SUBOFF Model) was performed using flow visualization and Digital Particle Image Velocimetry (DPIV). The model has an axisymmetric body with sail and fins, and it was supported by a streamlined strut that was formed by the extension of the sail appendage. The range of flow conditions studied correspond to a Reynolds numbers based on model length, Re_L, of about 10^5. Velocity vector fields, turbulence intensities, vorticity fields, and flow visualization in the vicinity of the junction flows are presented. In the vicinity of the control surface and sail hull junctions, the presence of streamwise vortices in the form of horseshoe or necklace vortices locally dominates the flow. The effects of unsteady motions about an axis passing through the sail are also investigated to understand the evolution of the unsteady wake.

  9. Minimally invasive surgery for atrial fibrillation

    PubMed Central

    Suwalski, Piotr

    2013-01-01

    Atrial fibrillation (AF) remains the most common cardiac arrhythmia, affecting nearly 2% of the general population worldwide. Minimally invasive surgical ablation remains one of the most dynamically evolving fields of modern cardiac surgery. While there are more than a dozen issues driving this development, two seem to play the most important role: first, there is lack of evidence supporting percutaneous catheter based approach to treat patients with persistent and long-standing persistent AF. Paucity of this data offers surgical community unparalleled opportunity to challenge guidelines and change indications for surgical intervention. Large, multicenter prospective clinical studies are therefore of utmost importance, as well as honest, clear data reporting. Second, a collaborative methodology started a long-awaited debate on a Heart Team approach to AF, similar to the debate on coronary artery disease and transcatheter valves. Appropriate patient selection and tailored treatment options will most certainly result in better outcomes and patient satisfaction, coupled with appropriate use of always-limited institutional resources. The aim of this review, unlike other reviews of minimally invasive surgical ablation, is to present medical professionals with two distinctly different, approaches. The first one is purely surgical, Standalone surgical isolation of the pulmonary veins using bipolar energy source with concomitant amputation of the left atrial appendage—a method of choice in one of the most important clinical trials on AF—The Atrial Fibrillation Catheter Ablation Versus Surgical Ablation Treatment (FAST) Trial. The second one represents the most complex approach to this problem: a multidisciplinary, combined effort of a cardiac surgeon and electrophysiologist. The Convergent Procedure, which includes both endocardial and epicardial unipolar ablation bonds together minimally invasive endoscopic surgery with electroanatomical mapping, to deliver best of

  10. Keratin gene mutations in disorders of human skin and its appendages.

    PubMed

    Chamcheu, Jean Christopher; Siddiqui, Imtiaz A; Syed, Deeba N; Adhami, Vaqar M; Liovic, Mirjana; Mukhtar, Hasan

    2011-04-15

    Keratins, the major structural protein of all epithelia are a diverse group of cytoskeletal scaffolding proteins that form intermediate filament networks, providing structural support to keratinocytes that maintain the integrity of the skin. Expression of keratin genes is usually regulated by differentiation of the epidermal cells within the stratifying squamous epithelium. Amongst the 54 known functional keratin genes in humans, about 22 different genes including, the cornea, hair and hair follicle-specific keratins have been implicated in a wide range of hereditary diseases. The exact phenotype of each disease usually reflects the spatial expression level and the types of mutated keratin genes, the location of the mutations and their consequences at sub-cellular levels as well as other epigenetic and/or environmental factors. The identification of specific pathogenic mutations in keratin disorders formed the basis of our understanding that led to re-classification, improved diagnosis with prognostic implications, prenatal testing and genetic counseling in severe keratin genodermatoses. Molecular defects in cutaneous keratin genes encoding for keratin intermediate filaments (KIFs) causes keratinocytes and tissue-specific fragility, accounting for a large number of genetic disorders in human skin and its appendages. These diseases are characterized by keratinocytes fragility (cytolysis), intra-epidermal blistering, hyperkeratosis, and keratin filament aggregation in severely affected tissues. Examples include epidermolysis bullosa simplex (EBS; K5, K14), keratinopathic ichthyosis (KPI; K1, K2, K10) i.e. epidermolytic ichthyosis (EI; K1, K10) and ichthyosis bullosa of Siemens (IBS; K2), pachyonychia congenita (PC; K6a, K6b, K16, K17), epidermolytic palmo-plantar keratoderma (EPPK; K9, (K1)), monilethrix (K81, K83, K86), ectodermal dysplasia (ED; K85) and steatocystoma multiplex. These keratins also have been identified to have roles in apoptosis, cell proliferation

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

    PubMed

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

    2016-04-12

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

  12. The Epidemiology of Atrial Fibrillation and Stroke.

    PubMed

    Pistoia, Francesca; Sacco, Simona; Tiseo, Cindy; Degan, Diana; Ornello, Raffaele; Carolei, Antonio

    2016-05-01

    The burden of stroke is increasing due to aging population and unhealthy lifestyle habits. The considerable rise in atrial fibrillation (AF) is due to greater diffusion of risk factors and screening programs. The link between AF and ischemic stroke is strong. The subtype most commonly associated with AF is cardioembolic stroke, which is particularly severe and shows the highest rates of mortality and permanent disability. A trend toward a higher prevalence of cardioembolic stroke in high-income countries is probably due to the greater diffusion of AF and the control of atherosclerotic of risk factors.

  13. Science Linking Pulmonary Veins and Atrial Fibrillation

    PubMed Central

    Mahida, Saagar; Sacher, Frederic; Derval, Nicolas; Berte, Benjamin; Yamashita, Seigo; Hooks, Darren; Denis, Arnaud; Amraoui, Sana; Hocini, Meleze; Haissaguerre, Michel; Jais, Pierre

    2015-01-01

    Over the past few decades, significant progress has been made in understanding the mechanistic basis of atrial fibrillation (AF). One of the most important discoveries in this context has been that pulmonary veins (PV) play a prominent role in the pathogenesis of AF. PV isolation has since become the most widely used technique for treatment of paroxysmal AF. Multiple studies have demonstrated that the electrophysiological and anatomical characteristics of PVs create a proarrhythmogenic substrate. The following review discusses the mechanistic links between PVs and AF. PMID:26835098

  14. NASA's First Atrial Fibrillation Case - Deke Slayton

    NASA Technical Reports Server (NTRS)

    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.

  15. Atrial conduction times and left atrial mechanical functions and their relation with diastolic function in prediabetic patients

    PubMed Central

    Gudul, Naile Eris; Karabag, Turgut; Sayin, Muhammet Rasit; Bayraktaroglu, Taner; Aydin, Mustafa

    2017-01-01

    Background/Aims The aim of this study was to investigate atrial conduction times and left atrial mechanical functions, the noninvasive predictors of atrial fibrillation, in prediabetic patients with impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). Methods Study included 59 patients (23 males, 36 females; mean age 52.5 ± 10.6 years) diagnosed with IFG or IGT by the American Diabetes Association criteria, and 43 healthy adults (22 males, 21 females; mean age 48.5 ± 12.1 years). Conventional and tissue Doppler echocardiography were performed. The electromechanical delay parameters were measured from the onset of the P wave on the surface electrocardiogram to the onset of the atrial systolic wave on tissue Doppler imaging from septum, lateral, and right ventricular annuli. The left atrial volumes were calculated by the disk method. Left atrial mechanical functions were calculated. Results The mitral E/A and E’/A’ ratios measured from the lateral and septal annuli were significantly lower in the prediabetics compared to the controls. The interatrial and left atrial electromechanical delay were significantly longer in prediabetic group compared to the controls. Left atrial active emptying volume (LAAEV) and fraction (LAAEF) were significantly higher in the prediabetics than the controls. LAAEV and LAAEF were significantly correlated with E/A, lateral and septal E’/A’. Conclusions In the prediabetic patients, the atrial conduction times and P wave dispersion on surface electrocardiographic were longer before the development of overt diabetes. In addition, the left atrial mechanical functions were impaired secondary to a deterioration in the diastolic functions in the prediabetic patients. PMID:27919159

  16. ECG Segmentation and P-Wave Feature Extraction: Application to Patients Prone to Atrial Fibrillation

    DTIC Science & Technology

    2007-11-02

    detection of patients prone to atrial fibrillation (AF), one of the most frequent arrhythmias. It focuses first on the segmentation of the...Keywords : atrial fibrillation , ECG segmentation, P-wave, hidden Markov model, wavelets, ECG database I. INTRODUCTION Atrial fibrillation (AF) is a very... atrial thrombosis, with the subsequent risk of a stroke. The aim of this study is to try to automatically detect patients prone to atrial fibrillation (AF

  17. Metamorphic labral axis patterning in the beetle Tribolium castaneum requires multiple upstream, but few downstream, genes in the appendage patterning network

    PubMed Central

    Smith, Frank W.; Angelini, David R.; Gaudio, Matthew; Jockusch, Elizabeth L.

    2014-01-01

    The arthropod labrum is an anterior appendage-like structure that forms the dorsal side of the preoral cavity. Conflicting interpretations of fossil, nervous system and developmental data have led to a proliferation of scenarios for labral evolution. The best supported hypothesis is that the labrum is a novel structure that shares development with appendages as a result of co-option. Here, we use RNA interference in the red flour beetle Tribolium castaneum to compare metamorphic patterning of the labrum to previously published data on ventral appendage patterning. As expected under the co-option hypothesis, depletion of several genes resulted in similar defects in the labrum and ventral appendages. These include proximal deletions and proximal-to-distal transformations resulting from depletion of the leg gap genes homothorax and extradenticle, large-scale deletions resulting from depletion of the leg gap gene Distal-less, and smaller distal deletions resulting from knockdown of the EGF ligand Keren. However, depletion of dachshund and many of the genes that function downstream of the leg gap genes in the ventral appendages had either subtle or no effects on labral axis patterning. This pattern of partial similarity suggests that upstream genes act through different downstream targets in the labrum. We also discovered that many appendage axis patterning genes have roles in patterning the epipharyngeal sensillum array, suggesting that they have become integrated into a novel regulatory network. These genes include Notch, Delta, and decapentaplegic, and the transcription factors abrupt, bric à brac, homothorax, extradenticle and the paralogs apterous a and apterous b. PMID:24617987

  18. Metamorphic labral axis patterning in the beetle Tribolium castaneum requires multiple upstream, but few downstream, genes in the appendage patterning network.

    PubMed

    Smith, Frank W; Angelini, David R; Gaudio, Matthew S; Jockusch, Elizabeth L

    2014-03-01

    The arthropod labrum is an anterior appendage-like structure that forms the dorsal side of the preoral cavity. Conflicting interpretations of fossil, nervous system, and developmental data have led to a proliferation of scenarios for labral evolution. The best supported hypothesis is that the labrum is a novel structure that shares development with appendages as a result of co-option. Here, we use RNA interference in the red flour beetle Tribolium castaneum to compare metamorphic patterning of the labrum to previously published data on ventral appendage patterning. As expected under the co-option hypothesis, depletion of several genes resulted in similar defects in the labrum and ventral appendages. These include proximal deletions and proximal-to-distal transformations resulting from depletion of the leg gap genes homothorax and extradenticle, large-scale deletions resulting from depletion of the leg gap gene Distal-less, and smaller distal deletions resulting from knockdown of the EGF ligand Keren. However, depletion of dachshund and many of the genes that function downstream of the leg gap genes in the ventral appendages had either subtle or no effects on labral axis patterning. This pattern of partial similarity suggests that upstream genes act through different downstream targets in the labrum. We also discovered that many appendage axis patterning genes have roles in patterning the epipharyngeal sensillum array, suggesting that they have become integrated into a novel regulatory network. These genes include Notch, Delta, and decapentaplegic, and the transcription factors abrupt, bric à brac, homothorax, extradenticle and the paralogs apterous a and apterous b.

  19. Righting and turning in mid-air using appendage inertia: reptile tails, analytical models and bio-inspired robots.

    PubMed

    Jusufi, A; Kawano, D T; Libby, T; Full, R J

    2010-12-01

    Unlike the falling cat, lizards can right themselves in mid-air by a swing of their large tails in one direction causing the body to rotate in the other. Here, we developed a new three-dimensional analytical model to investigate the effectiveness of tails as inertial appendages that change body orientation. We anchored our model using the morphological parameters of the flat-tailed house gecko Hemidactylus platyurus. The degree of roll in air righting and the amount of yaw in mid-air turning directly measured in house geckos matched the model's results. Our model predicted an increase in body roll and turning as tails increase in length relative to the body. Tails that swung from a near orthogonal plane relative to the body (i.e. 0-30° from vertical) were the most effective at generating body roll, whereas tails operating at steeper angles (i.e. 45-60°) produced only half the rotation. To further test our analytical model's predictions, we built a bio-inspired robot prototype. The robot reinforced how effective attitude control can be attained with simple movements of an inertial appendage.

  20. First description of a musculoskeletal linkage in an adipose fin: innovations for active control in a primitively passive appendage.

    PubMed

    Stewart, Thomas A; Hale, Melina E

    2013-01-07

    Adipose fins are enigmatic appendages found between the dorsal and caudal fins of some teleostean fishes. Long thought to be vestigial, degenerate second dorsal fins, remnants of the primitive gnathostome condition, adipose fins have since been recognized as novel morphologies. Unique among the fins of extant fishes, adipose fins have uniformly been described as passive structures, with no associated musculature. Here we provide the first description of a musculoskeletal linkage in an adipose fin, identified in the sun catfish Horabagrus brachysoma. Modified supracarinalis posterior muscles insert from the dorsal midline anterior to the adipose fin by tendons onto the fin base. An additional pair of posterior adipose-fin muscles also inserts upon the fin base and lay posterolateral to the fin, superficial to the axial muscle. This musculoskeletal linkage is an evolutionary innovation, a novel mechanism for controlling adipose-fin movement. These muscles appear to exemplify two approaches by which fins evolve to be actively controlled. We hypothesize that the anterior muscles arose through co-option of an existing fin linkage, while the posterior muscles originated as de novo fin muscles. These findings present adipose fins as a rich system within which to explore the evolution of novel vertebrate appendages.

  1. Molecular developmental evidence for a subcoxal origin of pleurites in insects and identity of the subcoxa in the gnathal appendages

    PubMed Central

    Coulcher, Joshua F.; Edgecombe, Gregory D.; Telford, Maximilian J.

    2015-01-01

    Pleurites are chitinous plates in the body wall of insects and myriapods. They are believed to be an adaptation to locomotion on land but their developmental and evolutionary origins are unclear. A widely endorsed explanation for their origin is through toughening pre-existing parts of the body wall; in contrast, the subcoxal theory suggests pleurites derive from a redeployment of the proximal-most section of the leg, the subcoxa. Here, by studying expression of appendage patterning genes in embryos and larvae of the beetle Tribolium castaneum, we provide the first molecular evidence for the existence of a cryptic subcoxal segment in developing legs. We follow this structure during development and show that the embryonic subcoxa later forms the pleurites of the larva as predicted by the subcoxal theory. Our data also demonstrate that subcoxal segments are present in all post-antennal appendages, including the first molecular evidence of a two-segmented mandible with a subcoxal segment in insects. PMID:26507752

  2. Frequency-tuning input-shaped manifold-based switching control for underactuated space robot equipped with flexible appendages

    NASA Astrophysics Data System (ADS)

    Kojima, Hirohisa; Ieda, Shoko; Kasai, Shinya

    2014-08-01

    Underactuated control problems, such as the control of a space robot without actuators on the main body, have been widely investigated. However, few studies have examined attitude control problems of underactuated space robots equipped with a flexible appendage, such as solar panels. In order to suppress vibration in flexible appendages, a zero-vibration input-shaping technique was applied to the link motion of an underactuated planar space robot. However, because the vibrational frequency depends on the link angles, simple input-shaping control methods cannot sufficiently suppress the vibration. In this paper, the dependency of the vibrational frequency on the link angles is measured experimentally, and the time-delay interval of the input shaper is then tuned based on the frequency estimated from the link angles. The proposed control method is referred to as frequency-tuning input-shaped manifold-based switching control (frequency-tuning IS-MBSC). The experimental results reveal that frequency-tuning IS-MBSC is capable of controlling the link angles and the main body attitude to maintain the target angles and that the vibration suppression performance of the proposed frequency-tuning IS-MBSC is better than that of a non-tuning IS-MBSC, which does not take the frequency variation into consideration.

  3. Imaging atrial arrhythmic intracellular calcium in intact heart

    PubMed Central

    Xie, Wenjun; Santulli, Gaetano; Guo, Xiaoxiao; Gao, Melanie; Chen, Bi-Xing; Marks, Andrew R.

    2014-01-01

    Abnormalities in intracellular Ca2+ signaling have been proposed to play an essential role in the pathophysiology of atrial arrhythmias. However, a direct observation of intracellular Ca2+ in atrial myocytes during atrial arrhythmias is lacking. Here, we have developed an ex vivo model of simultaneous Ca2+ imaging and electrocardiographic recording in cardiac atria. Using this system we were able to record atrial arrhythmic intracellular Ca2+ activities. Our results indicate that atrial arrhythmias can be tightly linked to intracellular Ca2+ waves and Ca2+ alternans. Moreover, we applied this strategy to analyze Ca2+ signals in the hearts of WT and knock-in mice harboring a ‘leaky’ type 2 ryanodine receptor (RyR2-R2474S). We showed that sarcoplasmic reticulum (SR) Ca2+ leak increases the susceptibility to Ca2+ alternans and Ca2+ waves increasing the incidence of atrial arrhythmias. Reduction of SR Ca2+ leak via RyR2 by acute treatment with S107 reduced both Ca2+ alternans and Ca2+ waves, and prevented atrial arrhythmias. PMID:24041536

  4. Cyclical stretch induces structural changes in atrial myocytes.

    PubMed

    De Jong, Anne Margreet; Maass, Alexander H; Oberdorf-Maass, Silke U; De Boer, Rudolf A; Van Gilst, Wiek H; Van Gelder, Isabelle C

    2013-06-01

    Atrial fibrillation (AF) often occurs in the presence of an underlying disease. These underlying diseases cause atrial remodelling, which make the atria more susceptible to AF. Stretch is an important mediator in the remodelling process. The aim of this study was to develop an atrial cell culture model mimicking remodelling due to atrial pressure overload. Neonatal rat atrial cardiomyocytes (NRAM) were cultured and subjected to cyclical stretch on elastic membranes. Stretching with 1 Hz and 15% elongation for 30 min. resulted in increased expression of immediate early genes and phosphorylation of Erk and p38. A 24-hr stretch period resulted in hypertrophy-related changes including increased cell diameter, reinduction of the foetal gene program and cell death. No evidence of apoptosis was observed. Expression of atrial natriuretic peptide, brain natriuretic peptide and growth differentiation factor-15 was increased, and calcineurin signalling was activated. Expression of several potassium channels was decreased, suggesting electrical remodelling. Atrial stretch-induced change in skeletal α-actin expression was inhibited by pravastatin, but not by eplerenone or losartan. Stretch of NRAM results in elevation of stress markers, changes related to hypertrophy and dedifferentiation, electrical remodelling and cell death. This model can contribute to investigating the mechanisms involved in the remodelling process caused by stretch and to the testing of pharmaceutical agents.

  5. Idiopathic atrial fibrillation in a champion Standardbred racehorse.

    PubMed

    Stewart, G A; Fulton, L J; McKellar, C D

    1990-05-01

    Atrial fibrillation is described in a champion pacer which earlier had been named Australian Harness Horse of the Year as a 3-year-old in 1986-87. Prior to conversion atrial fibrillation had been present for at least 6 weeks, during which the horse had not raced. Successful treatment was achieved with two 10g doses of quinidine sulphate per oesophageal tube, after slow digitalisation with intravenous digoxin over 4d. Four hours after commencement of quinidine therapy the arrhythmia had regressed to atrial flutter and converted to sinus rhythm 10 min later. Considering his age, standard of racing and high reputation the horse's overall performance as a 5-year-old after conversion from atrial fibrillation appeared comparable to his previous performance as a 4-year-old before the disorder occurred. In one of the wins since his return to sinus rhythm, the horse recorded his fastest winning speed and created a new track record at the major Melbourne racetrack. The absence of abnormalities of atrial and atrio-ventricular conduction after the cessation of the arrhythmia, together with the horse's return to successful racing, indicate that this was case of atrial fibrillation occurring as a functional disorder without persistent atrial pathology.

  6. Imaging atrial arrhythmic intracellular calcium in intact heart.

    PubMed

    Xie, Wenjun; Santulli, Gaetano; Guo, Xiaoxiao; Gao, Melanie; Chen, Bi-Xing; Marks, Andrew R

    2013-11-01

    Abnormalities in intracellular Ca(2+) signaling have been proposed to play an essential role in the pathophysiology of atrial arrhythmias. However, a direct observation of intracellular Ca(2+) in atrial myocytes during atrial arrhythmias is lacking. Here, we have developed an ex vivo model of simultaneous Ca(2+) imaging and electrocardiographic recording in cardiac atria. Using this system we were able to record atrial arrhythmic intracellular Ca(2+) activities. Our results indicate that atrial arrhythmias can be tightly linked to intracellular Ca(2+) waves and Ca(2+) alternans. Moreover, we applied this strategy to analyze Ca(2+) signals in the hearts of WT and knock-in mice harboring a 'leaky' type 2 ryanodine receptor (RyR2-R2474S). We showed that sarcoplasmic reticulum (SR) Ca(2+) leak increases the susceptibility to Ca(2+) alternans and Ca(2+) waves increasing the incidence of atrial arrhythmias. Reduction of SR Ca(2+) leak via RyR2 by acute treatment with S107 reduced both Ca(2+) alternans and Ca(2+) waves, and prevented atrial arrhythmias.

  7. [Metabolic syndrome and chronic persistent atrial fibrillation].

    PubMed

    Onuchina, E L; Solov'ev, O V; Mochalova, O V; Kononov, S K; Onuchin, S G

    2011-01-01

    The aim of the study was to elucidate specific features of chronic recurrent atrial fibrillation (AF) in patients with metabolic syndrome (MS) and disturbed carbohydrate metabolism compared with AF patients without MS. It enrolled 145 patients aged 44-83 years: 117 with abdominal obesity (BMI >30 kg/m2, waist circumference >80 and 94 cm in women and men respectively) including 30 without metabolic disturbances; 35 with impaired glucose tolerance (IGT), 52 with type 2 DM, and 28 controls without MS. Parameters measured included frequency and severity of AF, carbohydrate and lipid metabolism, albuminurea, C-reactive peptide level, quality of AH control, results of echocardiography and 24 hour ECG monitoring (sinus rhythm), and insulin resistance index (HOMA IRindex). Groups of AF and MS patients were dominated by women. The frequency and severity of AF relapses in MS patients were higher than in controls (especially in the presence of IGT and DM). IGT and DM2 associated with structural changes in myocardium (left atrial dilatation, prevalence of LV concentric hypertrophy, diastolic dysfunction) coupled to higher systolic AH and marked metabolic disorders (hyperglycemia, IR, elevated microalbuminurea and C-reactive protein level, dyslipidemia). These conditions contribute to the frequency and severity of AF relapses. Development of AF in MS is a multifactor problem necessitating strict control of AH, dyslipidemia, DM2 and IGT, reduction of body weight and abdominal obesity.

  8. Atrial Fibrillation Predictors: Importance of the Electrocardiogram.

    PubMed

    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.

  9. Relation of porphyria to atrial fibrillation.

    PubMed

    Dhoble, Abhijeet; Patel, Mehul B; Abdelmoneim, Sahar S; Puttarajappa, Chethan; Abela, George S; Bhatt, Deepak L; Thakur, Ranjan K

    2009-08-01

    Porphyrias are a group of inherited disorders affecting enzymes in the heme biosynthesis pathway, leading to overproduction and/or accumulation of porphyrin or its precursors. Porphyrias have been associated with autonomic dysfunction, which in turn can develop atrial fibrillation (AF). The purpose of this study was to characterize the prevalence of AF and atrial flutter (AFl) in patients with porphyrias. A single-center retrospective cohort study was designed using data from chart reviews of patients who were admitted to the hospital from January 2000 to June 2008. Fifty-six distinct cases were found with a discharge diagnosis of porphyria including all its subtypes. From the same database, age- and gender-matched controls were identified using computer-generated random numbers. We selected 1 age- and gender-matched control for each case. Electrocardiograms and echocardiograms were reviewed by 2 independent reviewers. Only patients with available 12-lead electrocardiograms that showed AF/AFl were labeled with that diagnosis. All patients with a diagnosis of porphyria were included in the study irrespective of their age. Seven of 56 patients with porphyria met inclusion criteria, yielding a prevalence of AF/AFl of 12.5%. This association was significant (p = 0.028, relative risk 7.45, 95% confidence interval 1.01 to 66.14) compared with the age- and gender-matched control group (2%). In conclusion, our observations suggest that porphyria may be significantly associated with AF/AFl.

  10. [Right atrial thrombosis with acute abdominal onset].

    PubMed

    Petcu, D P; Petcu, C; Roşu, M

    2009-01-01

    Intracardiac masses are detected more frequently due to the availability of echocardiography. Right atrial thrombosis is rare comparatively with that of the left atrium. The clinical presentation of the patient with right atrial thrombosis is linked with a misleading association between cardiovascular signs and digestive signs (acute abdominal pain, vomiting and marmorated skin of flanks). Initial clinical suspicions of acute pancreatitis, entero-mesenteric infarction and complicated gastro-duodenal ulcer were invalidated by imagistic investigations -- echocardiography and CT. The massive thrombus located in the right atrium, prolapsing during diastole through the tricuspid valve, was associated with the increase in plasmatic D-dimers and new ECG modifications type right bundle block (hemodynamic straining of the right ventricle). The evolution was favorable, after heparin-therapy by infusing pump, with relief of cardiovascular and digestive symptoms after the first 6 hours; after 36 h from the beginning of the treatment the thrombus was lysed. Sudden death likelihood through complete obstruction of the tricuspid ostium was prevented due to the early diagnosis offered by imagistic methods.

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  12. [Cardioversion of atrial fibrillation with low energy internal electric shock].

    PubMed

    Ricard, P; Socas, A G; Taramasco, V; Guenoun, M; Lévy, S

    1997-12-01

    The efficacy and safety of low internal cardioversion for the reduction of atrial fibrillation was assessed prospectively in 104 consecutive patients. Sixty-two patients had chronic atrial fibrillation (Group I). 16 patients had paroxysmal atrial fibrillation (Group II) and 26 patients had induced atrial fibrillation (Group III). The average duration of the current episode of atrial fibrillation was 9 +/- 19 months in Group I, 4 +/- 2 days in Group II and 18 +/- 7 minutes in Group III. Two intracardiac defibrillation catheters were used, one (the cathode) in the right atrium and the other in the coronary sinus or left branch of the pulmonary artery (anode). These catheters were connected to an external defibrillator delivering biphasic 3/3 ms shocks with a voltage which could be programmed from 10 to 400 volts. The shocks were synchronised on the R wave. Sinus rhythm was restored in 44 of the 62 patients in Group I (70%), 12 of the 16 patients in Group II (75%) and 20 of the 26 patients in Group III (77%). The average voltages and energies restoring sinus rhythm were 300 +/- 68 volts and 3.5 +/- 1.5 joules respectively in Group I, 245 +/- 72 volts and 2.0 +/- 2.9 joules in Group II, and 270 +/- 67 volts and 2.6 +/- 1.2 joules in Group III. These results show that the energy required to restore sinus rhythm is significantly greater in patients with chronic atrial fibrillation than in patients with paroxysmal or induced atrial fibrillation. There were no ventricular proarrhythmic effects in the 686 shocks synchronised on the R wave. This study shows that internal cardioversion of atrial fibrillation is feasible with low energies under simple sedation. These results support the concept of an implantable atrial defibrillator.

  13. Atrial Arrhythmias in Astronauts - Summary of a NASA Summit

    NASA Technical Reports Server (NTRS)

    Barr, Yael R.; Watkins, Sharmila D.; Polk, J. D.

    2010-01-01

    Background and Problem Definition: To evaluate NASA s current standards and practices related to atrial arrhythmias in astronauts, Space Medicine s Advanced Projects Section at the Johnson Space Center was tasked with organizing a summit to discuss the approach to atrial arrhythmias in the astronaut cohort. Since 1959, 11 cases of atrial fibrillation, atrial flutter, or supraventricular tachycardia have been recorded among active corps crewmembers. Most of the cases were paroxysmal, although a few were sustained. While most of the affected crewmembers were asymptomatic, those slated for long-duration space flight underwent radiofrequency ablation treatment to prevent further episodes of the arrhythmia. The summit was convened to solicit expert opinion on screening, diagnosis, and treatment options, to identify gaps in knowledge, and to propose relevant research initiatives. Summit Meeting Objectives: The Atrial Arrhythmia Summit brought together a panel of six cardiologists, including nationally and internationally renowned leaders in cardiac electrophysiology, exercise physiology, and space flight cardiovascular physiology. The primary objectives of the summit discussions were to evaluate cases of atrial arrhythmia in the astronaut population, to understand the factors that may predispose an individual to this condition, to understand NASA s current capabilities for screening, diagnosis, and treatment, to discuss the risks associated with treatment of crewmembers assigned to long-duration missions or extravehicular activities, and to discuss recommendations for prevention or management of future cases. Summary of Recommendations: The summit panel s recommendations were grouped into seven categories: Epidemiology, Screening, Standards and Selection, Treatment of Atrial Fibrillation Manifesting Preflight, Atrial Fibrillation during Flight, Prevention of Atrial Fibrillation, and Future Research

  14. Abnormal heart rate variability and atrial fibrillation after aortic surgery

    PubMed Central

    Compostella, Leonida; Russo, Nicola; D’Onofrio, Augusto; Setzu, Tiziana; Compostella, Caterina; Bottio, Tomaso; Gerosa, Gino; Bellotto, Fabio

    2015-01-01

    Introduction Complete denervation of transplanted heart exerts protective effect against postoperative atrial fibrillation; various degrees of autonomic denervation appear also after transection of ascending aorta during surgery for aortic aneurysm. Objective This study aimed to evaluate if the level of cardiac denervation obtained by resection of ascending aorta could exert any effect on postoperative atrial fibrillation incidence. Methods We retrospectively analysed the clinical records of 67 patients submitted to graft replacement of ascending aorta (group A) and 132 with aortic valve replacement (group B); all episodes of postoperative atrial fibrillation occurred during the 1-month follow-up have been reported. Heart Rate Variability parameters were obtained from a 24-h Holter recording; clinical, echocardiographic and treatment data were also evaluated. Results Overall, 45% of patients (group A 43%, group B 46%) presented at least one episode of postoperative atrial fibrillation. Older age (but not gender, abnormal glucose tolerance, ejection fraction, left atrial diameter) was correlated with incidence of postoperative atrial fibrillation. Only among a subgroup of patients with aortic transection and signs of greater autonomic derangement (heart rate variability parameters below the median and mean heart rate over the 75th percentile), possibly indicating more profound autonomic denervation, a lower incidence of postoperative atrial fibrillation was observed (22% vs. 54%). Conclusion Transection of ascending aorta for repair of an aortic aneurysm did not confer any significant protective effect from postoperative atrial fibrillation in comparison to patients with intact ascending aorta. It could be speculated that a limited and heterogeneous cardiac denervation was produced by the intervention, creating an eletrophysiological substrate for the high incidence of postoperative atrial fibrillation observed. PMID:25859868

  15. Pulmonary edema following transcatheter closure of atrial septal defect

    PubMed Central

    Chigurupati, Keerthi; Reshmi, Liza Jose; Gadhinglajkar, Shrinivas; Venkateshwaran, S.; Sreedhar, Rupa

    2015-01-01

    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. PMID:26139760

  16. Biventricular repair of right atrial isomerism with complex congenital anomalies.

    PubMed

    Kirali, Kaan; Sasmazel, Ahmet; Mataraci, Ilker; Erdem, Hasan; Guzelmeric, Fusun

    2010-01-01

    Biventricular repair is usually difficult to achieve in patients who have right atrial isomerism, which is typically associated with other complex cardiac anomalies. The procedure can be used in patients who have balanced ventricular structures. Herein, we report a successful surgical reconstruction, including biventricular repair, in a 4-year-old boy. The child's right atrial isomerism was associated with double-outlet right ventricle, a large atrial septal defect, a subaortic ventricular septal defect, valvular and infundibular pulmonary stenosis, left persistent superior vena cava, and hemiazygos continuation of an interrupted inferior vena cava. Balanced ventricles enabled biventricular repair, which we consider to be preferable to the Fontan procedure in such circumstances.

  17. Surviving Right Atrial Rupture From Blunt Thoracic Trauma After Pericardiectomy.

    PubMed

    Lajevardi, Sepehr Seyed; Galougahi, Keyvan Karimi; Nova, George; Marshman, David

    2016-02-01

    Right atrial rupture secondary to blunt trauma is exceedingly rare. We present a case report of blunt chest trauma and right atrial rupture in a patient with a background of pericardiectomy that were successfully managed surgically. Right atrial rupture must be considered as a differential diagnosis in patients with blunt chest trauma. In patients with previous pericardiectomy, this injury may manifest with massive hemothorax, and insertion of a chest drain should be performed with extreme caution. In our experience, urgent exploratory thoracotomy and repair of the defect are the mainstays of acute management.

  18. Lateral Atrial Tunnel Fontan Operation Predisposes to the Junctional Rhythm.

    PubMed

    Januszewska, Katarzyna; Schuh, Anna; Lehner, Anja; Dalla-Pozza, Robert; Malec, Edward

    2017-02-10

    The goal of the study was to compare the early postoperative course after fenestrated lateral atrial tunnel (LT) and non-fenestrated extracardiac conduit (EC) Fontan operation (FO) in a single center where both techniques were parallelly used. Between 2004 and 2012, 56(32.7%) children underwent LT and 113(66.1%) EC FO. The mean age was 3.7 ± 2.9 years and mean weight was 14.6 ± 7.3 kg. The most common malformation was hypoplastic left heart syndrome (50.9%). The general approach was to perform LT in children after hemi-Fontan operation and EC in patients after Glenn anastomosis. Medical records were retrospectively reviewed. The hospital survival was 100%. In EC group, cardiopulmonary bypass time (CPB) was shorter (p = 0.004) and less patients needed aortic cross-clamping (p < 0.001). Children after EC stayed longer in the hospital (p = 0.016) and manifested more often prolonged effusions (p = 0.038). The incidence of all forms of junctional rhythm was higher in the LT group, early postoperatively (p < 0.001), during hospitalization (p = 0.004) and at discharge (p < 0.001). Children after LT required more often temporary pacemaker stimulation (p < 0.001). Patients without postoperative normofrequent sinus rhythm had longer CPB time (p = 0.008) and were more often operated on with aortic cross-clamping (p = 0.028). Lateral atrial tunnel Fontan operation with fenestration facilitates early adaptation to the total passive pulmonary flow, but predisposes the patients to the loss of sinus rhythm. The crucial role in the preservation of sinus rhythm plays the last step of the multistage surgery of the single ventricle malformations, probably not only the surgical technique but also factors associated with the cardiopulmonary bypass.

  19. Changes in Left Ventricular Filling in Patients with Persistent Atrial Fibrillation

    PubMed Central

    Naji, Franjo; Pagliaruzzi, Mihael; Penko, Meta; Kanic, Vojko; Vokac, Damijan

    2013-01-01

    BACKGROUND: Former studies showed possible interrelationship between altered ventricular filling patterns and atrial fibrillation (AF). HYPOTHESIS: Long term persistent AF has a negative impact on left ventricular filling in patients with preserved ejection fraction of left ventricle. METHODS: Our study was designed as a prospective case control study. We included 40 patients with persistent AF and preserved ejection fraction after successful electrical cardioversion and 43 control patients. Persistent AF was defined as AF lasting more than 4 weeks. Cardiac ultrasound was performed in all patients 24 hours after the procedure. Appropriate mitral flow and tissue Doppler velocities as well as standard echocardiographic measurements were obtained. RESULTS: There were no significant differences between both groups' parameters regarding age, sex, commorbidities or drug therapy. Analysis of mitral flow velocities showed significant increase of E value in AF group (0.96±0.27 vs.0.70±0.14; p = 0.001). Tissue Doppler measurements didn't reveal any differences in early diastolic movement, however there was a statistically significant difference in E/Em values of both groups, respectively (12.0±4.0 vs. 9.0±2.1; p= 0.001). CONCLUSION: Our study shows that in patients with preserved systolic function and persistent AF shortly after cardioversion diastolic ventricular filling patterns are altered mainly due to increased left atrial pressure and not due to impaired diastolic relaxation of left ventricle. Further studies are needed in order to define the interplay between diminished atrial function and impaired ventricular filling. PMID:24324364

  20. 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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  1. Event synchronous adaptive filter based atrial activity estimation in single-lead atrial fibrillation electrocardiograms.

    PubMed

    Lee, Jeon; Song, Mi-hye; Shin, Dong-gu; Lee, Kyoung-joung

    2012-08-01

    In this paper, an event synchronous adaptive filter (ESAF) is proposed to estimate atrial activity (AA) from a single-lead AF ECG in real time. The proposed ESAF is a kind of adaptive filter designed to have the reference fed with the impulse train synchronized with the R peak in a raw atrial fibrillation (AF) ECG and to input the timely delayed AF ECG into the primary input. To assess the performance, for ten simulated AF ECGs, the cross-correlation coefficient (ρ) and the normalized mean square error (NMSE) between estimated AAs and ten original simulated AAs were calculated and, for ten real AF ECGs, the ventricular residue (VR) in QRS interval and similarity (S) in non-QRS interval were computed. As a result, these four parameters were revealed as ρ = 0.938 ± 0.016 and NMSE = 0.243 ± 0.051 for simulated AF ECGs and VR = 1.190 ± 0.476 and S = 0.967 ± 0.041 for real AF ECGs. These results were found to be better than those of the averaged beat subtraction (ABS) method, which had been previously considered the only way to estimate AA automatically in real time. In conclusion, even with single-lead AF ECGs, the proposed method estimated AAs accurately and calculated the atrial fibrillatory frequencies, the most valuable index in AF maintenance and therapy evaluation, with a remarkably low computational cost.

  2. Blood pressure control and the reduction of left atrial overload is essential for controlling atrial fibrillation.

    PubMed

    Tanabe, Yasuko; Kawamura, Yuichiro; Sakamoto, Naka; Sato, Nobuyuki; Kikuchi, Kenjiro; Hasebe, Naoyuki

    2009-07-01

    The purpose of this study was to investigate whether the ideal control of atrial fibrillation (AF) associated with hypertensive patients depends on the usage of renin-angiotensin system (RAS) inhibitors or whether it occurs regardless of the kind of antihypertensive agents used. The control of AF was compared in 112 outpatients between 1) those with or without the administration of RAS inhibitors, and 2) those with an ideal or poor control of the blood pressure (BP) regardless of the kind of antihypertensive therapy used. The therapies with or without RAS inhibitors did not yield any significant difference in the AF control states, even though RAS inhibitors had been administered to the patient group with a high proportion of organic heart disease. The ideal BP control group exhibited a significantly better AF control in comparison to the poor BP control group. The former group had a significantly smaller left atrial diameter determined by ultrasonic echocardiography. BP control itself may essentially be important for preventing AF in the general patient population. Poor BP control seemed to have an affect on worsening AF possibly via left ventricular diastolic dysfunction, followed by left atrial overload.

  3. Coronary steal by left atrial myxoma: a case report.

    PubMed

    Alvarez, Jose Rubio; Quiroga, Juan Sierra; Cereijo, Jose Manuel Martinez; Lopez, Laura Reija

    2009-06-18

    This report describes a 41-year-old man who had atypical angina resulting from coronary steal by left atrial myxoma. The tumor was completely excised and the patient was symptoms free after operation.

  4. [Current state of treatment strategies for atrial fibrillation].

    PubMed

    Rogge, C; Hilbert, S; Dagres, N; Hindricks, G

    2016-05-01

    Atrial fibrillation is the most common form of persistent cardiac arrhythmia with a greatly increasing prevalence due to an aging population and increasing cardiovascular risk factors. Apart from impairment of the quality of life atrial fibrillation is associated with a high morbidity, most importantly stroke and heart failure. The therapy is complex and aims at improving symptoms as well as the prevention of thromboembolic complications, heart failure and aggravating comorbidities. Based on individual patient characteristics and symptoms therapy is mainly based on heart rate control by pharmacological means or therapy for maintaining sinus rhythm. This treatment includes antiarrhythmic drugs and catheter ablation. Current research is aimed at the investigation of the electrophysiological mechanisms of recurrent therapy refractive atrial fibrillation and the question whether the maintenance of sinus rhythm can improve the prognosis of atrial fibrillation.

  5. Apixaban for the prevention of stroke in atrial fibrillation.

    PubMed

    Littrell, Rachel; Flaker, Greg

    2012-02-01

    Until recently, pharmaceutical options for stroke prevention in atrial fibrillation were restricted to aspirin or vitamin K antagonist therapy. In recent years development has been underway for alternatives. Apixaban, a direct Factor Xa inhibitor, is orally dosed, target selective and has few known drug or food interactions. As such, it is a member of a new generation of anticoagulants expected to revolutionize the way we approach anticoagulation for stroke prevention in atrial fibrillation. Apixaban has been studied in Phase II and Phase III trials for a variety of indications. The AVERROES trial established apixaban as superior to aspirin for stroke reduction in patients with atrial fibrillation for whom vitamin K antagonist therapy is unsuitable. The recent ARISTOTLE trial found apixaban to be superior to warfarin for stroke prevention in a wide range of patients with atrial fibrillation, with significantly lower bleeding risk, and lower risk of all-cause mortality.

  6. Cardiac adipose tissue and atrial fibrillation: the perils of adiposity.

    PubMed

    Hatem, Stéphane N; Redheuil, Alban; Gandjbakhch, Estelle

    2016-04-01

    The amount of adipose tissue that accumulates around the atria is associated with the risk, persistence, and severity of atrial fibrillation (AF). A strong body of clinical and experimental evidence indicates that this relationship is not an epiphenomenon but is the result of complex crosstalk between the adipose tissue and the neighbouring atrial myocardium. For instance, epicardial adipose tissue is a major source of adipokines, inflammatory cytokines, or reactive oxidative species, which can contribute to the fibrotic remodelling of the atrial myocardium. Fibro-fatty infiltrations of the subepicardium could also contribute to the functional disorganization of the atrial myocardium. The observation that obesity is associated with distinct structural and functional remodelling of the atria has opened new perspectives of treating AF substrate with aggressive risk factor management. Advances in cardiac imaging should lead to an improved ability to visualize myocardial fat depositions and to localize AF substrates.

  7. Successful treatment of atrial tachycardias with flecainide acetate.

    PubMed Central

    Creamer, J E; Nathan, A W; Camm, A J

    1985-01-01

    Intravenous flecainide successfully terminated atrial tachycardia in three patients. Maintenance treatment with oral flecainide prevented the recurrence of tachycardia for up to three years. These results suggest an additional use for flecainide which should be further explored. PMID:3966957

  8. Incidence and Prognosis of Atrial Fibrillation in Patients With Sepsis

    PubMed Central

    Wells, Gretchen L.; Morris, Peter E.

    2011-01-01

    Background Although the mortality rate among patients with sepsis is declining, the incidence of both sepsis and sepsis-related deaths is increasing, likely due to its presence in a growing elderly population. As atrial fibrillation is more common in the elderly, we hypothesize that its presence will be associated with greater mortality among patients with sepsis. Methods The Medical Intensive Care Unit (MICU) database of a large tertiary care medical center was queried for sepsis-related codes and atrial fibrillation. Results Atrial fibrillation was associated with older age and a higher mortality in this series of patients with sepsis. Conclusions Whether atrial fibrillation is a marker of disease severity or contributes to mortality is uncertain. Further studies are necessary to determine optimal management.

  9. Atrial fibrillation, progression of coronary atherosclerosis and myocardial infarction.

    PubMed

    Bayturan, Ozgur; Puri, Rishi; Tuzcu, E Murat; Shao, Mingyuan; Wolski, Kathy; Schoenhagen, Paul; Kapadia, Samir; Nissen, Steven E; Sanders, Prashanthan; Nicholls, Stephen J

    2017-03-01

    Background Despite atrial fibrillation representing an established risk factor for stroke, the association between atrial fibrillation and both progression of coronary atherosclerosis and major adverse cardiovascular events is not well characterized. We assessed the serial measures of coronary atheroma burden and cardiovascular outcomes in patients with and without atrial fibrillation. Methods Data were analyzed from nine clinical trials involving 4966 patients with coronary artery disease undergoing serial intravascular ultrasonography at 18-24 month intervals to assess changes in percent atheroma volume (PAV). Using a propensity weighted analysis, and following adjustment for baseline variables, patients with ( n = 190) or without ( n = 4776) atrial fibrillation were compared with regard to coronary plaque volume and major adverse cardiovascular events (death, myocardial infarction, and stroke). Results Atrial fibrillation patients demonstrated lower baseline PAV (36.0 ± 8.9 vs. 38.1 ± 8.9%, p = 0.002) and less PAV progression (-0.07 ± 0.34 vs. + 0.23 ± 0.34%, p = 0.001) compared with the non-atrial fibrillation group. Multivariable analysis revealed atrial fibrillation to independently predict both myocardial infarction [HR, 2.41 (1.74,3.35), p<0.001] 2.41 (1.74, 3.35), p < 0.00) and major adverse cardiovascular events [HR, 2.2, (1.66, 2.92), p<0.001] 2.20 (1.66, 2.92), p < 0.001]. Kaplan-Meier analysis showed that atrial fibrillation compared with non-atrial fibrillation patients had a significantly higher two-year cumulative incidence of overall major adverse cardiovascular events (4.4 vs. 2.0%, log-rank p = 0.02) and myocardial infarction (3.3 vs. 1.5%, log-rank p = 0.05). Conclusions The presence of atrial fibrillation independently associates with a heightened risk of myocardial infarction despite a lower baseline burden and progression rate of coronary atheroma. Further studies are necessary to define

  10. Renal Denervation Suppresses the Inducibility of Atrial Fibrillation in a Rabbit Model for Atrial Fibrosis

    PubMed Central

    Zhou, Genqing; Chen, Songwen; Ouyang, Ping; Liu, Shaowen

    2016-01-01

    Renal denervation (RD) was reported to reduce the susceptibility of atrial fibrillation (AF), but the underlying mechanism has not been well understood. This study was performed to investigate the effect of RD on the inducibility of AF in a rabbit model for atrial fibrosis and to explore the potential mechanisms. Thirty-five rabbits were randomly assigned into sham-operated group (n = 12), abdominal aortic constriction (AAC) group (n = 12) and AAC with RD (AAC-RD) group (n = 11). The incidence of AF induced by burst pacing in atriums was determined. Blood was collected to measure the levels of rennin, angiotensin II and aldosterone. Atrial samples were preserved to evaluate protein and gene expression of collagen, connective tissue growth factor (CTGF) and transforming growth factor-β1 (TGF-β1). Our data suggested cardiac structure remodeling and atrial fibrosis were successfully induced by AAC. Compared with the AAC group, the AAC-RD rabbits had smaller ascending aortic diameter and left ventricular end-systolic diameter. For burst pacing at the left atrium (LA), AF was induced in two of the 12 rabbits in the sham-operated group, 10 of the 12 rabbits in the AAC group, and 2 of the 11 rabbits in the AAC-RD group, with great difference among the three groups (P = 0.001). The percentage of LA burst stimulations with induced AF achieved 47.2% in the AAC group, which was higher than those in both the AAC-RD (12.1%) and the Sham-operated (5.6%) groups. Significantly increasing intercellular space in the AAC group (P<0.001) compared with the sham-operated rabbits. RD clearly decreased the volume fraction of collagen in LA and right atrium compared with that of the AAC group (P< 0.01). AAC-induced elevation of collagen I, CTGF and TGF-β1 was suppressed by RD. In conclusion, RD suppressed the inducibility of AF in a rabbit model for pressure associated atrial fibrosis, potentially by modulating renin-angiotensin-aldosterone system and decreasing pro-fibrotic factors

  11. [Spontaneous hematoma of the atrial wall].

    PubMed

    Iglesias López, A; Rodríguez Pan, A; Pazos Silva, V

    2014-01-01

    The clinical signs of heart masses tend to be nonspecific, generally depending more on their repercussions on heart function caused by their location rather than on their type. Imaging techniques make it possible to limit the differential diagnosis of heart masses based on their location, morphology, and characteristics of echogenicity, density, or intensity, depending on the technique used to study them. We present the case of a woman with squeezing mid chest pain irradiating to her shoulder and positive cardiac markers in whom a left atrial mass was identified at echocardiography. This finding was confirmed at chest CT. The signs at chest CT were compatible with a mural hematoma and this diagnosis was confirmed after intraoperative biopsy.

  12. Individualising Anticoagulant Therapy in Atrial Fibrillation Patients

    PubMed Central

    2016-01-01

    Non-vitamin K antagonist (VKA) oral anticoagulants (NOACs) have emerged as alternatives to VKAs for the prevention of stroke in patients with non-valvular atrial fibrillation. Four NOACS: dabigatran, apixaban, rivaroxaban and edoxaban, have received regulatory approval in Europe from the European Medicines Agency. Numerous factors can influence the decision to prescribe a NOAC, the most important of which are assessment of stroke and bleeding risks. Given the variation in design of the pivotal phase III clinical trials investigating the efficacy and safety of NOACs, and in the absence of head-to-head comparative data, it is impossible to recommend one NOAC over the other. However, NOACS offer the opportunity for individualised therapy based on factors such as renal function, age or patient/doctor preference for once- or twice-daily dosing regimens. Dose reduction of some NOACS should be considered in at-risk patient populations. PMID:27617088

  13. [Antenatal atrial tachycardia. Two case reports].

    PubMed

    Pavlova, M; Lupoglazoff, J M; Denjoy, I; Luton, D; Magnier, S; Casasoprana, A; Azancot, A

    2001-05-01

    The authors report two cases of foetal supraventricular tachycardia in healthy hearts with 1/1 atrioventricular conduction which turned out to be atrial tachycardias in the postnatal period. The first foetus had permanent tachycardia at 190/minute at 34 weeks' amenorrhea with left ventricular dysfunction at 36 weeks. In the postnatal period, treatment with digoxine and amiodarone restored sinus rhythm and normal left ventricular function. Permanent foetal tachycardia, even at a rate of less than 200 beats/minute, should suggest an arrhythmia and may lead to left ventricular dysfunction in utero. The other foetus had an aneurysm of the foramen ovale with paroxysmal tachycardias at 220/minute without cardiac dysfunction. A Holter at 1 month showed paroxysmalatrial tachycardia. Postnatal rhythm monitoring is necessary in paroxysmal foetus tachycardia, especially with prenatal aneurysm of the foramen ovale.

  14. Pharmacological Tests in Atrial Fibrillation Ablation

    PubMed Central

    Gourraud, Jean-Baptiste; Andrade, Jason G; Macle, Laurent

    2016-01-01

    The invasive management of atrial fibrillation (AF) has been considerably changed by the identification of major sites of AF initiation and/or maintenance within the pulmonary vein antra. Percutaneous catheter ablation of these targets has become the standard of care for sustained maintenance of sinus rhythm. Long-term failure of ablation is related to an inability to create a durable transmural lesion or to identify all of the non-pulmonary vein arrhythmia triggers. Pharmacological challenges during catheter ablation have been suggested to improve outcomes in both paroxysmal and persistent AF. Herein we review the mechanism and evidence for the use of pharmacological adjuncts during the catheter ablation of AF. PMID:28116081

  15. Atrial Fibrillation, Cognitive Decline And Dementia

    PubMed Central

    Alonso, Alvaro; Arenas de Larriva, Antonio P.

    2016-01-01

    Atrial fibrillation (AF) is a common cardiac arrhythmia. Growing evidence supports a role for AF as a risk factor for cognitive decline and dementia. In this review, we summarize epidemiologic observations linking AF with cognitive outcomes, describe potential mechanisms, and explore the impact of AF treatments on cognitive decline and dementia. Community-based, observational studies show a consistent higher rate of cognitive decline and risk of dementia in persons with AF. These associations are partly due to the increased risk of clinical stroke in AF, but other mechanisms, including incidence of silent cerebral infarcts, microbleeds, and cerebral hypoperfusion, are likely additional contributors. Adequate oral anticoagulation and improved management of the overall cardiovascular risk profile in persons with AF offer the promise of reducing the impact of AF on cognitive decline and dementia. PMID:27547248

  16. Perspectives and controversies in atrial fibrillation.

    PubMed

    Prystowsky, E N

    1998-08-20

    Atrial fibrillation (AF) is the most common sustained arrhythmia in humans. The 3 basic tenets of therapy are (1) restoration and maintenance of sinus rhythm; (2) ventricular rate control; and (3) prevention of thromboembolism. Maintenance of sinus rhythm appears preferable to rate control alone in patients with significant symptoms caused by AF. Complete suppression of AF with drug therapy for >6 months is unusual, but it is not the sole criterion of success. As with other chronic cardiac disorders such as angina and heart failure, a marked reduction in frequency and duration of episodes of AF will likely translate into an excellent clinical outcome. The major risk of antiarrhythmic drug therapy is ventricular proarrhythmia, which is seen most frequently in patients with substantial left ventricular dysfunction. Torsade de pointes is the most frequent proarrhythmia that occurs with antiarrhythmic agents that prolong ventricular repolarization and the QT interval. To minimize the risk of proarrhythmia, antiarrhythmic drugs are started in-hospital in patients with significant heart disease, and agents are selected based on certain patient characteristics. For example, the drugs initially selected for patients with heart failure and coronary artery disease are amiodarone and sotalol, respectively. Two approaches may be used to decrease the thromboembolic risk associated with cardioversion of AF to sinus rhythm. In the conventional method, warfarin is given (INR 2.0-3.0) for 3 weeks before and at least 4 weeks after cardioversion. An alternative approach employs transesophageal echocardiography to rule out left atrial thrombi before cardioversion. Both methods appear reasonable and safe, and I prefer the conventional and transesophageal echocardiography-guided approaches for outpatients and in-hospital patients, respectively.

  17. Comparative analysis of gene expression patterns in the arthropod labrum and the onychophoran frontal appendages, and its implications for the arthropod head problem.

    PubMed

    Janssen, Ralf

    2017-01-01

    The arthropod head problem has troubled scientists for more than a century. The segmental composition of the arthropod head, homology of its appendages, and especially the nature of the most anterior region of the head are still, at least partially, unclear. One morphological feature of the head that is in the center of current debate is the labrum (upper lip), a fleshy appendicular structure that covers the arthropod mouth. One hypothesis is that the labrum represents a fused pair of protocerebral limbs that likely are homologous with the frontal appendages (primary antennae) of extant onychophorans and the so-called great appendages of stem arthropods. Recently, this hypothesis obtained additional support through genetic data, showing that six3, an anterior-specific gene, is exclusively expressed in the arthropod labrum and the onychophoran frontal appendages, providing an additional line of evidence for homology. Here I present data that put this finding into perspective. The outcome of my study shows that the homologization of a morphological structure by the expression of a single genetic factor is potentially misleading.

  18. Ciliopathy-associated gene Cc2d2a promotes assembly of subdistal appendages on the mother centriole during cilia biogenesis.

    PubMed

    Veleri, Shobi; Manjunath, Souparnika H; Fariss, Robert N; May-Simera, Helen; Brooks, Matthew; Foskett, Trevor A; Gao, Chun; Longo, Teresa A; Liu, Pinghu; Nagashima, Kunio; Rachel, Rivka A; Li, Tiansen; Dong, Lijin; Swaroop, Anand

    2014-06-20

    The primary cilium originates from the mother centriole and participates in critical functions during organogenesis. Defects in cilia biogenesis or function lead to pleiotropic phenotypes. Mutations in centrosome-cilia gene CC2D2A result in Meckel and Joubert syndromes. Here we generate a Cc2d2a(-/-) mouse that recapitulates features of Meckel syndrome including embryonic lethality and multiorgan defects. Cilia are absent in Cc2d2a(-/-) embryonic node and other somatic tissues; disruption of cilia-dependent Shh signalling appears to underlie exencephaly in mutant embryos. The Cc2d2a(-/-) mouse embryonic fibroblasts (MEFs) lack cilia, although mother centrioles and pericentriolar proteins are detected. Odf2, associated with subdistal appendages, is absent and ninein is reduced in mutant MEFs. In Cc2d2a(-/-) MEFs, subdistal appendages are lacking or abnormal by transmission electron microscopy. Consistent with this, CC2D2A localizes to subdistal appendages by immuno-EM in wild-type cells. We conclude that CC2D2A is essential for the assembly of subdistal appendages, which anchor cytoplasmic microtubules and prime the mother centriole for axoneme biogenesis.

  19. Automatic Detection of Atrial Fibrillation Using Basic Shannon Entropy of RR Interval Feature

    NASA Astrophysics Data System (ADS)

    Afdala, Adfal; Nuryani, Nuryani; Satriyo Nugroho, Anto

    2017-01-01

    Atrial Fibrillation is one of heart disease, that common characterized by irregularity heart beat. Atrial fibrillation leads to severe complications such as cardiac failure with the subsequent risk of a stroke. A method to detect atrial fibrillation is needed to prevent a risk of atrial fibrillation. This research uses data from physionet in atrial fibrillation database category. The performance of Shannon entropy has the highest accuracy if a threshold is 0.5 with accuracy 89.79%, sensitivity 91.04% and specificity 89.01%. Based on the result we get a conclusion, the ability of Shannon entropy to detect atrial fibrillation is good.

  20. Reflex effects on the heart of stimulating left atrial receptors

    PubMed Central

    Furnival, C. M.; Linden, R. J.; Snow, H. M.

    1971-01-01

    1. Stimulation of left atrial receptors, by distension of the pulmonary vein/left atrial junctions, is known to cause a reflex increase in heart rate; the efferent pathway is known to be solely in the sympathetic nerves. 2. In expectation of a concomitant positive inotropic response the effect of stimulating the left atrial receptors on the inotropic state of the left ventricle was studied, using as a known sensitive index of inotropic changes the maximal rate of rise of pressure in the left ventricle (dP/dt max). 3. Stimulation of left atrial receptors resulted in an increase in heart rate but there were no significant concomitant changes in dP/dt max. 4. It is concluded that activity in this discrete efferent pathway does not include an inotropic effect on the left ventricle and therefore the reflex involves only those sympathetic nerves which innervate the sinu-atrial node. 5. The possible function of atrial receptors in the regulation of heart volumes is discussed. PMID:5124571

  1. Distinct pharmacologic substrate in lidocaine-sensitive, repetitive atrial tachycardia.

    PubMed

    Chiale, Pablo A; Faivelis, Luciano; Garro, Hugo A; Fernández, Pablo A; Herrera Paz, Juan J; Elizari, Marcelo V

    2012-06-01

    Lidocaine-sensitive, repetitive atrial tachycardia is an uncommon arrhythmia. The electrophysiologic substrate is still unknown, and the pharmacologic responses have not been fully explored. The aim of this study was to investigate the effects of intravenous adenosine and verapamil in patients with lidocaine-sensitive atrial tachycardia. In 9 patients with repetitive uniform atrial tachycardia, the response to intravenous adenosine (12 mg), lidocaine (1 mg/kg body weight), and verapamil (10 mg) were sequentially investigated. Simultaneous 12-lead electrocardiogram (ECG) was recorded at baseline and continuously monitored thereafter. Tracings were obtained at regularly timed intervals right after the administration of each drug to evaluate changes in the arrhythmia characteristics. Repetitive atrial tachycardia was abolished by intravenous lidocaine in the 9 patients within the first 2 minutes after the end of injection. Adenosine suppressed the arrhythmia in 2 patients and shortened the runs of atrial ectopic activity in 1 patient, while verapamil was effective in 2 patients, 1 of them insensitive to adenosine and the other 1 sensitive to this agent. In 5 patients, the arrhythmia was abolished by radiofrequency ablation at different sites of the right atrium. Lidocaine-sensitive atrial tachycardia may eventually be also suppressed by adenosine and/or verapamil. This suggests that this enigmatic arrhythmia may be caused by different underlying electrophysiologic substrates and that at least in some cases, delayed afterdepolarizations seem to play a determining role.

  2. Hybrid therapy in the management of atrial fibrillation.

    PubMed

    Starek, Zdenk; Lehar, Frantisek; Jez, Jiri; Wolf, Jiri; Novák, Miroslav

    2015-01-01

    Atrial fibrillation is the most common sustained arrhythmia. Because of the sub-optimal outcomes and associated risks of medical therapy as well as the recent advances in non-pharmacologic strategies, a multitude of combined (hybrid) algorithms have been introduced that improve efficacy of standalone therapies while maintaining a high safety profile. Antiarrhythmic administration enhances success rate of electrical cardioversion. Catheter ablation of antiarrhythmic drug-induced typical atrial flutter may prevent recurrent atrial fibrillation. Through simple ablation in the right atrium, suppression of atrial fibrillation may be achieved in patients with previously ineffective antiarrhythmic therapy. Efficacy of complex catheter ablation in the left atrium is improved with antiarrhythmic drugs. Catheter ablation followed by permanent pacemaker implantation is an effective and safe treatment option for selected patients. Additional strategies include pacing therapies such as atrial pacing with permanent pacemakers, preventive pacing algorithms, and/or implantable dual-chamber defibrillators are available. Modern hybrid strategies combining both epicardial and endocardial approaches in order to create a complex set of radiofrequency lesions in the left atrium have demonstrated a high rate of success and warrant further research. Hybrid therapy for atrial fibrillation reviews history of development of non-pharmacological treatment strategies and outlines avenues of ongoing research in this field.

  3. Management of Atrio-Esophageal Fistula Following Left Atrial Ablation

    PubMed Central

    Yousuf, Tariq; Keshmiri, Hesam; Bulwa, Zachary; Kramer, Jason; Sharjeel Arshad, Hafiz Muhammad; Issa, Rasha; Woznicka, Daniel; Gordon, Paul; Abi-Mansour, Pierre

    2016-01-01

    Currently, no guidelines have been established for the treatment of atrio-esophageal fistula (AEF) secondary to left atrial ablation therapy. After comprehensive literature review, we aim to make suggestions on the management of this complex complication and also present a case series. We performed a review of the existing literature on AEF in the setting of atrial ablation. Using keywords atrial fibrillation, atrial ablation, fistula formation, atrio-esophageal fistula, complications, interventions, and prognosis, a search was made using the medical databases PUBMED and MEDLINE for reports in English from 2000 to April 2015. A statistical analysis was performed to compare the three different intervention arms: medical management, stent placement and surgical intervention. The results of our systematic review confirm the high mortality rate associated with AEF following left atrial ablation and the necessity to diagnose atrio-esophageal injury in a timely manner. The mortality rates of this complication are 96% with medical management alone, 100% with stent placement, and 33 % with surgical intervention. Atrio-esophageal injury and subsequent AEF is an infrequent but potentially fatal complication of atrial ablation. Early, prompt, and definitive surgical intervention is the treatment of choice. PMID:28197267

  4. [Atrial fibrillation and regular tachycardia in two young patients--are both treated with atrial fibrillation ablation?].

    PubMed

    von Bodman, G; Brömsen, J; Kopf, C; Füller, M; Block, M

    2014-04-17

    Two young patients with documented episodes of symptomatic paroxysmal atrial fibrillation have been referred for pulmonary vein isolation. Both patients had a history of concomitant regular tachycardia. in both cases pulmonaryvein isolation has not been performed but in each patient a supraventricular tachycardia (right focal atrial tachycardia/atrioventricular reentry tachycardia) could be induced and ablated instead. Concomitant supraventricular tachycardia acting as a trigger arrhythmia is frequent in young patients with atrial fibrillation without underlying cardiacdisease. In these patients a concomitant supra-ventricular tachycardia should beexcluded by electrophysiological study or ablated before pulmonary vein isolation or initiating an antiarrhythmic drug therapy. In most cases ablation of supraventricular tachycardia is safe and successful whereas the risks of ablative therapy of atrial fibrillation can not be neglected and success is moderate.

  5. Analysis of atrial</