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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 Aneurysm.

    PubMed

    Hosseini, Saeid; Hashemi, Arash; Saedi, Sedigheh; Jalili, Farshad; Maleki, Majid; Jalalian, Rozita; Rezaei, Yousef

    2016-09-01

    Left atrial appendage aneurysms (LAAA) are extremely rare. This condition is usually diagnosed incidentally or after the occurrence of thrombotic events or cardiac tachyarrhythmias in the second to fourth decades of life. It can predispose to hazardous adverse events, including atrial fibrillation, myocardial infarction, and systemic thromboembolism. We report a case of LAAA in a 68-year-old woman presenting with atypical chest pain, exertional dyspnea, and episodes of sudden-onset palpitation. Aneurysmectomy with the patient under cardiac arrest with cardiopulmonary bypass was performed. In addition, we explore the diagnosis, management, and prognosis of this entity through a meticulous literature review. PMID:27549544

  3. 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

  4. Cardioembolic Stroke in Atrial Fibrillation-Rationale for Preventive Closure of the Left Atrial Appendage

    PubMed Central

    Leithäuser, Boris

    2009-01-01

    Atrial fibrillation is the most common cardiac arrhythmias, and a major cause of morbidity and mortality due to cardioembolic stroke. The left atrial appendage is the major site of thrombus formation in non-valvular atrial fibrillation. Loss of atrial systole in atrial fibrillation and increased relative risk of associated stroke point strongly toward a role for stasis of blood in left atrial thrombosis, although thrombus formation is multifactorial, and much more than blood flow irregularities are implicated. Oral anticoagulation with vitamin-K-antagonists is currently the most effective prophylaxis for stroke in atrial fibrillation. Unfortunately, this treatment is often contraindicated, particularly in the elderly, in whom risk of stroke is high. Moreover, given the risk of major bleeding, there is reason to be skeptical of the net benefit when warfarin is used in those patients. This work reviews the pathophysiology of cardioembolic stroke and critically spotlights the current status of preventive anticoagulation therapy. Various techniques to exclude the left atrial appendage from circulation were discussed as a considerable alternative for stroke prophylaxis. PMID:19997539

  5. Recurrent syncope after left atrial appendage occlusion.

    PubMed

    Cruz-Gonzalez, Ignacio; Perez-Rivera, Jose-Angel; Bethencourt, Armando

    2015-02-01

    We present the case of a 72-year-old woman with permanent atrial fibrillation and contraindication to long-term oral anticoagulant therapy who underwent left atrial appendage (LAA) occlusion. A 24-mm Amplatzer Cardiac Plug (St Jude Medical) device was deployed. The inferior part of the external disc of the device appeared to be over the posterior leaflet of the mitral valve but no significant mitral stenosis or mitral regurgitation was detected before deployment. After the procedure the patient suffered several syncopes when she tried to stand up. A transesophageal echocardiography (TEE) was performed and no significant differences on the device position were detected, it was not possible to perform the TEE in a stand-up position due to the patient symptoms (hypotension, tachycardia, dizziness, and loss of consciousness). After discussion with the surgical team, surgical removal of the device and surgical exclusion of LAA was performed. The symptoms disappeared and the patient was discharged. In the best of our knowledge, this is the first time that recurrent syncope has been described as a complication of LAA occlusion. PMID:25044597

  6. Comparison of tissue Doppler dynamics with Doppler flow in evaluating left atrial appendage function by transesophageal echocardiography in prehypertensive and hypertensive patients.

    PubMed

    Tenekecioğlu, Erhan; Karabulut, Aziz; Yilmaz, Mustafa

    2010-07-01

    Increased blood pressure (BP) is associated with an increase in cardiovascular mortality and morbidity. We aimed to analyze the effect of increased BP onto the function of left atrial appendage (LAA) in early stages of hypertension. Transesophageal echocardiography (TEE) was prospectively performed to assess LAA functions in 120 patients with increased BP, and in 58 normotensive subjects without cardiovascular disease. Patients with increased BP were divided according to Joint National Committee VII (JNC VII) report: prehypertensive, stage-1 hypertensive and stage-2 hypertensive patients. During TEE, LAA late-emptying velocities (LAAEV) were significantly reduced only in stage-2 hypertensives as compared with control group (P < 0.001). In contrast, LAA late-contracting velocity (LAA TDI-D2) was significantly reduced in prehypertensive,stage-1 hypertensive and stage-2 hypertensive patients, when compared with control group (P < 0.05, P < 0.001, and P < 0.001, respectively). The LAA maximal areas were increased significantly only in stage-2 hypertensive patients when compared with control group (P < 0.05). During TEE, left atrial spontaneous echocardiographic contrast was found in 2 of 36 patients in prehypertension group, in 7 of 40 patients in stage-1 hypertension group, and in 10 of 44 patients in stage-2 hypertension group. Left atrial thrombi were observed in 3 (6.8%) patients of stage-2 hypertension group. In conclusion, in patients with untreated prehypertension and hypertension, elevation of afterload imposed on left atrium involved both left atrium and LAA, resulting in impairment of the LAA function. Tissue Doppler imaging (TDI) enables the detection of this functional impairment in early stages of hypertension, even in prehypertensive phase, when compared with conventional Doppler flow measurement of the LAA. Even in prehypertensive phase, BP should be decreased to normal levels to prevent the LAA dysfunction. PMID:20345441

  7. [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. PMID:26261929

  8. Do left atrial appendage morphology and function help predict thromboembolic risk in atrial fibrillation?

    PubMed

    Anselmino, Matteo; Gili, Sebastiano; Castagno, Davide; Ferraris, Federico; Matta, Mario; Rovera, Chiara; Giustetto, Carla; Gaita, Fiorenzo

    2016-03-01

    Clinical scores (i.e. CHA2DS2-VASc) are the mainstay of thromboembolic risk management in nonvalvular atrial fibrillation. Nonetheless, they bear some limitations to precisely define risk-benefit ratio of oral anticoagulation (OAC), both with vitamin K antagonists and with novel direct oral anticoagulants, especially in patients with low-intermediate scores. Cardiovascular imaging, allowing directly visualization of those pathophysiological alterations, which may lead to the formation of intracardiac thrombi, offers itself as a unique tool helping to refine thromboembolic risk stratification. Many parameters have been tested, focusing primarily on functional and morphological variables of the left atrium and left atrial appendage (LAA). Left atrium volume and LAA peak flow velocity have, for a longtime, been associated with increased thromboembolic risk, whereas some new parameters, such as left atrium fibrosis assessed by late-gadolinium enhanced (LGE) MRI, left atrium and LAA strain and LAA morphology have more recently shown some ability in predicting embolic events in atrial fibrillation patients. Overall, however, these parameters have seen, to date, scarce clinical implementation, especially because of the inconsistency of validated cutoffs and/or strong clinical evidence driven by technical limitations, such as expensiveness of the technologies (i.e. MRI or computed tomography), invasiveness (i.e. transesophageal echocardiography) or limited reproducibility (i.e. LGE MRI). In conclusion, to date, cardiovascular imaging plays a limited role; however, validation and diffusion of the new techniques hereby systematically presented hold the potential to refine thromboembolic risk stratification in nonvalvular atrial fibrillation. PMID:26556443

  9. Calcified amorphous tumor of the left atrial appendage.

    PubMed

    Watanabe, Yusuke; Naganuma, Toru; Nakao, Tatsuya; Nakamura, Sunao

    2016-01-01

    A 57-year-old female with end-stage renal dysfunction was admitted to our hospital. The echocardiogram revealed a 9mm×22mm hyperechoic mass in the left atrial appendage (LAA). The mass was extremely mobile. Considering the high risk of embolic events, we decided on a surgical resection. Microscopic examination of the mass revealed a nodular focus of calcification and fibrosis with focal chronic inflammation of the atrial endocardium. The endocardium was uniformly thickened with no evidence of neoplastic proliferation. The mass was diagnosed with a calcified amorphous tumor (CAT). This is first report of CAT of the LAA. PMID:26964029

  10. Cardiac Computed Tomography Angiography for Left Atrial Appendage Closure.

    PubMed

    Saw, Jacqueline; Lopes, Joao Pedro; Reisman, Mark; McLaughlin, Patrick; Nicolau, Savvas; Bezerra, Hiram G

    2016-08-01

    Atrial fibrillation is prevalent and percutaneous left atrial appendage (LAA) closure is increasingly performed worldwide. This procedure is technically challenging and the success and procedural complexities depend on anatomy of the LAA and surrounding structures. These are readily depicted on cardiac computed tomography angiography (CCTA), which offers unique imaging planes. CCTA allows not only preplanning anatomic LAA assessment, but can also be used to evaluate for pre-existing LAA thrombus, and done postprocedure for surveillance for device-related thrombus, residual leak, and complications. In this article, we review the practical utility of CCTA for LAA closure. PMID:26907169

  11. Possible Role for Cryoballoon Ablation of Right Atrial Appendage Tachycardia when Conventional Ablation Fails

    PubMed Central

    Kilic, Ayhan

    2015-01-01

    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. PMID:26175651

  12. Percutaneous Left Atrial Appendage Ligation for Stroke Prevention in Atrial Fibrillation.

    PubMed

    Valderrábano, Miguel; Price, Matthew J

    2015-01-01

    Prevention of thromboembolic complications in atrial fibrillation remains a tremendous clinical challenge. Knowledge that the left atrial appendage (LAA) is the most common anatomical origin of cardioembolic strokes1 has been the main motivation to develop clinical and procedural strategies to exclude the LAA from the circulation, either surgically or percutaneously. This review discusses the rationale behind these strategies, their relative merits, and future prospects for LAA exclusion strategies. PMID:26306126

  13. Atrial Tachycardias Arising from the Atrial Appendages and Aortic Sinus of Valsalva

    PubMed Central

    Taylor, Colleen M; Samardhi, Himabindu; Haqqani, Haris M

    2015-01-01

    Focal atrial tachycardias arising from the atrial appendages and the aortic sinuses of Valsalva are less frequently encountered in clinical practice. This review article describes the clinical presentation, surface P wave morphology, electrophysiologic characteristics and treatment of these arrhythmias. Catheter ablation of these focal tachycardias has a high success rate. It is however important to be aware of specific anatomic considerations in these locations for optimal treatment outcomes with low complication rates. PMID:25308812

  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. Left atrial appendage dysfunction in a patient with premature ventricular contractions - a risk factor for stroke?

    PubMed

    Patel, Sandeep M; Ackerman, Michael J; Asirvatham, Samuel J

    2013-01-01

    A 16-year-old female with ventricular dysfunction and frequent ventricular arrhythmia presented with a cardioembolic stroke. Prior electrophysiology study and ablation was performed for ventricular tachycardia (VT). For remaining ventricular ectopy, the patient was maintained on carvedilol and mexiletine. After one year on this regimen, she presented with an acute stroke. Transesophageal echocardiography revealed no evidence of an intracardiac or ventricular thrombus but demonstrated markedly decreased left atrial appendage (LAA) flow velocity worsened during frequent premature ventricular contractions (PVC). In the absence of atrial fibrillation (AF), the LAA dysfunction was considered secondary to the frequent PVCs and was thought to be the underlying cause for the stroke. We present this case to highlight a potential under recognized association between LAA dysfunction and ventricular arrhythmia, similar to that observed with atrioventricular dyssynchronous pacing. PMID:24086095

  16. Closure of Left Atrial Appendage With Persistent Distal Thrombus Using an Amplatzer Amulet Occluder.

    PubMed

    Lange, Mathias; Bültel, Helmut; Weglage, Heinrich; Löffeld, Patrick; Wichter, Thomas

    2016-09-01

    A 73-year-old patient with permanent atrial fibrillation presented for left atrial appendage (LAA) occlusion. Transesophageal echocardiography demonstrated a thrombus in the distal LAA. This image series illustrates a "no touch" technique that was used to ensure successful implantation of an Amplatzer Amulet LAA occlusion device without the use of an embolization protection system. PMID:27591691

  17. Incomplete Closure of the Left Atrial Appendage: Implication and Management.

    PubMed

    Aryana, Arash; d'Avila, André

    2016-09-01

    Incomplete left atrial appendage closure (LAAC) occurs in ∼30-40 % of cases following both surgical and percutaneous closure methods. Incomplete surgical LAAC may further be classified as incompletely surgically ligated LAA (ISLL) or LAA stump. ISLL is associated with a significantly increased risk of thrombus formation/thromboembolism. Moreover, this risk is highest in the absence of oral anticoagulation (OAC) and inversely correlates with the size of the ISLL neck. Not only routine screening for ISLL seems critical, but also long-term OAC should strongly be considered in this high-risk cohort. Alternatively, complete endocardial occlusion using a surrogate method may represent a reasonable option, particularly in those intolerant to long-term OAC therapy. Although thrombus formation/thromboembolic events have also been described in patients with incomplete LAAC following percutaneous occlusion, an association between the two remains less clear. However, given the rise and growing interest in percutaneous LAAC methods, additional research in this area is clearly warranted. PMID:27443378

  18. [Catheter-based closure of the left atrial appendage : Stroke prevention in atrial fibrillation].

    PubMed

    Skurk, C; Leistner, D M; Park, J-W; Landmesser, U

    2016-09-01

    In patients with nonvalvular atrial fibrillation, >90 % of thrombi are detected in the left atrial appendage (LAA). In particular these observations have resulted in the development of catheter-based LAA closure as an approach for stroke prevention in patients with nonvalvular atrial fibrillation in recent years. A preliminary randomized trial provided promising data with respect to efficacy and safety of this approach as compared to anticoagulation with warfarin. The safety of the procedure has been significantly improved in recent years due to procedural experience and refinement of implanted devices. In current clinical practice, this approach is particularly used for patients with nonvalvular atrial fibrillation, a significant ischemic risk (CHA2DS2-VASc score ≥2), and a high bleeding risk, i. e., in patients in whom there are relevant concerns with respect to long-term anticoagulation. The present article discusses the data from randomized clinical studies and registries, the present guideline recommendations, and the practical clinical use of LAA closure for stroke prevention. PMID:27534868

  19. 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. PMID:27354151

  20. 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.

  1. Resolution of a warfarin and dabigatran-resistant left atrial appendage thrombus with apixaban.

    PubMed

    Miwa, Yosuke; Minamishima, Toshinori; Sato, Toshiaki; Sakata, Konomi; Yoshino, Hideaki; Soejima, Kyoko

    2016-06-01

    The majority of embolisms associated with atrial fibrillation (AF) are from the left atrial appendage (LAA). To treat the existing thrombus, warfarin and novel anticoagulants have been used. However, there has been no clinical information regarding the difference of the effects of congealing the fibrinogenolysis system among these oral anticoagulants. Here, we report a case of persistent AF, in whom apixaban, factor Xa inhibitor resolved an LAA clot refractory to warfarin and direct thrombin inhibition. Factor Xa inhibitor, apixaban, could resolve the left appendage thrombosis refractory to warfarin and dabigatran. PMID:27354873

  2. The Left Atrial Appendage: Target for Stroke Reduction in Atrial Fibrillation.

    PubMed

    Ramlawi, Basel; Abu Saleh, Walid K; Edgerton, James

    2015-01-01

    A patient with atrial fibrillation (AF) has a greater than 5% annual risk of major stroke, a 5-fold increase compared to the general population. While anticoagulation remains the standard stroke prevention strategy, the nature of lifelong anticoagulation inevitably carries an increased risk of bleeding, increased stroke during periods of interruption, increased cost, and significant lifestyle modification. Many patients with atrial fibrillation have had their left atrial appendage (LAA) ligated or excised by surgeons during cardiac surgery, a decision based largely on intuition and with no clear evidence of efficacy in stroke risk reduction. The observation that 90% of the thrombi found in nonvalvular AF patients and 57% found in valvular AF are in the LAA, triggered significant interest in the LAA as a potential therapeutic target. Until recently, the results were inconsistent, and high rates of incomplete occlusions precluded the medical community from confirming a definite relationship between LAA and stroke. As a result, anticoagulation is still the recommended first-line stroke risk reduction in AF, and the American College of Cardiology/American Heart Association guidelines recommend LAA exclusion only with surgical ablation of AF or in the context of concomitant mitral valve surgery. A handful of devices have been developed for LAA exclusion. This includes percutaneous options such as WATCHMAN™ Left Atrial Appendage Closure Device (Boston Scientific Corporation, Marlborough, MA), hybrid epicardial devices such as the LARIAT Suture Delivery Device (SentreHEART, Inc., Redwood City, CA), and epicardial surgical devices such as AtriClip® LAA Occlusion System (AtriCure, Inc., West Chester, OH). Studies of the Watchman device have shown noninferiority to Warfarin in stroke prevention and this device has recently gained approval from the U.S. Food and Drug Administration (FDA) following lengthy delays due to safety concerns. The Lariat device, which received 510

  3. Percutaneous left atrial appendage closure: Technical aspects and prevention of periprocedural complications with the watchman device.

    PubMed

    Möbius-Winkler, Sven; Majunke, Nicolas; Sandri, Marcus; Mangner, Norman; Linke, Axel; Stone, Gregg W; Dähnert, Ingo; Schuler, Gerhard; Sick, Peter B

    2015-02-26

    Transcatheter closure of the left atrial appendage has been developed as an alternative to chronic oral anticoagulation for stroke prevention in patients with atrial fibrillation, and as a primary therapy for patients with contraindications to chronic oral anticoagulation. The promise of this new intervention compared with warfarin has been supported by several, small studies and two pivotal randomized trial with the Watchman Device. The results regarding risk reduction for stroke have been favourable although acute complications were not infrequent. Procedural complications, which are mainly related to transseptal puncture and device implantation, include air embolism, pericardial effusions/tamponade and device embolization. Knowledge of nature, management and prevention of complications should minimize the risk of complications and allow transcatheter left atrial appendage closure to emerge as a therapeutic option for patients with atrial fibrillation at risk for cardioembolic stroke. PMID:25717354

  4. Percutaneous left atrial appendage closure: Technical aspects and prevention of periprocedural complications with the watchman device

    PubMed Central

    Möbius-Winkler, Sven; Majunke, Nicolas; Sandri, Marcus; Mangner, Norman; Linke, Axel; Stone, Gregg W; Dähnert, Ingo; Schuler, Gerhard; Sick, Peter B

    2015-01-01

    Transcatheter closure of the left atrial appendage has been developed as an alternative to chronic oral anticoagulation for stroke prevention in patients with atrial fibrillation, and as a primary therapy for patients with contraindications to chronic oral anticoagulation. The promise of this new intervention compared with warfarin has been supported by several, small studies and two pivotal randomized trial with the Watchman Device. The results regarding risk reduction for stroke have been favourable although acute complications were not infrequent. Procedural complications, which are mainly related to transseptal puncture and device implantation, include air embolism, pericardial effusions/tamponade and device embolization. Knowledge of nature, management and prevention of complications should minimize the risk of complications and allow transcatheter left atrial appendage closure to emerge as a therapeutic option for patients with atrial fibrillation at risk for cardioembolic stroke. PMID:25717354

  5. Percutaneous left atrial appendage occlusion for stroke prevention in atrial fibrillation: an update

    PubMed Central

    De Backer, O; Arnous, S; Ihlemann, N; Vejlstrup, N; Jørgensen, E; Pehrson, S; Krieger, T D W; Meier, P; Søndergaard, L; Franzen, O W

    2014-01-01

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia encountered in clinical practice. One of its most devastating complications is the development of thromboembolism leading to fatal or disabling stroke. Oral anticoagulation (OAC, warfarin) is the standard treatment for stroke prevention in patients with AF with an increased stroke risk. However, there are several obstacles to long-term OAC therapy, including the risk of serious bleeding, several drug–drug interactions and the need for frequent blood testing. Although newer oral anticoagulants have been developed, these drugs also face issues of major bleeding and non-compliance. Therefore, alternative treatment options for stroke prevention in patients with AF with a high stroke risk are needed. Percutaneous left atrial appendage (LAA) occlusion is an evolving therapy, which should be taken into consideration in those patients with non-valvular AF with a high stroke risk and contraindications for OAC. This article aims to discuss the rationale for LAA closure, the available LAA occlusion devices and their clinical evidence until now. Moreover, we discuss the importance of proper patient selection, the role of various imaging techniques and the need for a more tailored postprocedural antithrombotic therapy. PMID:25332785

  6. Left Atrial Appendage Closure Guided by Integrated Echocardiography and Fluoroscopy Imaging Reduces Radiation Exposure

    PubMed Central

    Balzer, Jan; Eickholt, Christian; Petersen, Margot; Kehmeier, Eva; Veulemans, Verena; Kelm, Malte; Willems, Stephan; Meyer, Christian

    2015-01-01

    Aims To investigate whether percutaneous left atrial appendage (LAA) closure guided by automated real-time integration of 2D-/3D-transesophageal echocardiography (TEE) and fluoroscopy imaging results in decreased radiation exposure. Methods and Results In this open-label single-center study LAA closure (AmplatzerTM Cardiac Plug) was performed in 34 consecutive patients (8 women; 73.1±8.5 years) with (n = 17, EN+) or without (n = 17, EN-) integrated echocardiography/fluoroscopy imaging guidance (EchoNavigator® [EN]; Philips Healthcare). There were no significant differences in baseline characteristics between both groups. Successful LAA closure was documented in all patients. Radiation dose was reduced in the EN+ group about 52% (EN+: 48.5±30.7 vs. EN-: 93.9±64.4 Gy/cm2; p = 0.01). Corresponding to the radiation dose fluoroscopy time was reduced (EN+: 16.7±7 vs. EN-: 24.0±11.4 min; p = 0.035). These advantages were not at the cost of increased procedure time (89.6±28.8 vs. 90.1±30.2 min; p = 0.96) or periprocedural complications. Contrast media amount was comparable between both groups (172.3±92.7 vs. 197.5±127.8 ml; p = 0.53). During short-term follow-up of at least 3 months (mean: 8.1±5.9 months) no device-related events occurred. Conclusions Automated real-time integration of echocardiography and fluoroscopy can be incorporated into procedural work-flow of percutaneous left atrial appendage closure without prolonging procedure time. This approach results in a relevant reduction of radiation exposure. Trial Registration ClinicalTrials.gov NCT01262508 PMID:26465747

  7. 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

  8. Determinants of Left Atrial Appendage Volume in Stroke Patients without Chronic Atrial Fibrillation

    PubMed Central

    Taina, Mikko; Sipola, Petri; Muuronen, Antti; Hedman, Marja; Mustonen, Pirjo; Kantanen, Anne-Mari; Jäkälä, Pekka; Vanninen, Ritva

    2014-01-01

    Background Left atrial appendage (LAA) volume has been shown to be increased in patients with acute cryptogenic stroke. Atrial fibrillation (AF) is a well-recognized risk factor but it is not the only one associated with LAA enlargement. The aim of the study was to clarify the multifactorial etiology of LAA enlargement in cardiogenic stroke/TIA patients without AF. Methods Altogether 149 patients with suspected cardioembolic stroke/TIA (47 females; mean age 61 years) underwent cardiac CT. Diagnosed AF on admittance was an exclusion criteria but 24-hour Holter ambulatory ECG revealed paroxysmal AF (PAF) in 20 patients. Body surface area adjusted LAA volume was evaluated. Eighteen different variables were registered including general characteristics, definite and potential causal risk factors for ischemic stroke/TIA, clinical echoparameters and CT based cardiac volumetric and adipose tissue measurements. A stepwise linear regression analysis was performed to achieve a model adjusted for the number of predictors of LAA volume increase. Results In linear regression analysis, the best model accounted for 30% of the variability in LAA volume, including PAF (19%) and enlarged left atrial volume (6%), enlarged left ventricle end-systolic diameter (3%) and decreased pericardial adipose tissue (2%). No multi-colinearity between variables was observed. In addition to PAF, no other definitive or potential causal risk factors could account for the LAA volume in these patients. Conclusions LAA volume increase seems to be poorly associated with currently known stroke/TIA risk factors, except for AF. Targeting more comprehensive ECG monitoring for stroke patients with increased LAA volume should be considered. PMID:24595515

  9. 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

  10. Plain radiographic diagnosis of thrombosis of left atrial appendage in mitral valve disease

    SciTech Connect

    Matsuyama, S.; Watabe, T.; Kuribayashi, S.; Ootaki, M.; Suzuki, Y.; Sugihara, M.; Kawada, S.; Koide, S.; Shohtsu, A.; Tomoda, H.

    1983-01-01

    Conventional posteroanterior chest radiographs of 42 patients with mitral valve disease who had had surgery were analyzed, and particular attention was directed to the presence or absence of the convexity of the left lower midcardiac border (left artrial segment). The flatness or concavity of this segment, despite other evidence of left atrial enlargement, was observed in six (60%) of 10 patients who had left atrial thrombosis, and in three (9%) of 32 patients who did not have thrombosis (false positive diagnosis). Four of the 10 patients who had left atrial thrombosis did not show this finding on the radiographs (false negative diagnosis). One of these four had a thrombus only against the posterior wall of the body of the left atrium. Therefore, the accuracy in the diagnosis of thrombosis of the left atrial appendage was 66.7% (six of nine) for patients who had thrombosis of the appendage. Standard chest radiographs are important in the evaluation of the patient with thrombosis of the left atrial appendage.

  11. 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

  12. 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

  13. Early Experience Using a Left Atrial Appendage Occlusion Device in Patients with Atrial Fibrillation

    PubMed Central

    Kim, Yung Ly; Joung, Boyoung; On, Young Keun; Shim, Chi Young; Lee, Moon Hyoung; Kim, Young-Hoon

    2012-01-01

    Purpose Atrial fibrillation (AF) is one of the major risk factors for ischemic stroke, and 90% of thromboembolisms in these patients arise from the left atrial appendage (LAA). Recently, it has been documented that an LAA occlusion device (OD) is not inferior to warfarin therapy, and that it reduces mortality and risk of stroke in patients with AF. Materials and Methods We implanted LAA-ODs in 5 Korean patients (all male, 59.8±7.3 years old) with long-standing persistent AF or permanent AF via a percutaneous trans-septal approach. Results 1) The major reasons for LAA-OD implantation were high risk of recurrent stroke (80%), labile international neutralizing ratio with hemorrhage (60%), and 3/5 (60%) patients had a past history of failed cardioversion for rhythm control. 2) The mean LA size was 51.3±5.0 mm and LAA size was 25.1×30.1 mm. We implanted the LAA-OD (28.8±3.4 mm device) successfully in all 5 patients with no complications. 3) After eight weeks of anticoagulation, all patients switched from warfarin to anti-platelet agent after confirmation of successful LAA occlusion by trans-esophageal echocardiography. Conclusion We report on our early experience with LAA-OD deployment in patients with 1) persistent or permanent AF who cannot tolerate anticoagulation despite significant risk of ischemic stroke, or 2) recurrent stroke in patients who are unable to maintain sinus rhythm. PMID:22187236

  14. Left Atrial Appendage Morphology in Patients with Suspected Cardiogenic Stroke without Known Atrial Fibrillation

    PubMed Central

    Korhonen, Miika; Muuronen, Antti; Arponen, Otso; Mustonen, Pirjo; Hedman, Marja; Jäkälä, Pekka; Vanninen, Ritva; Taina, Mikko

    2015-01-01

    The left atrial appendage (LAA) is the typical origin for intracardiac thrombus formation. Whether LAA morphology is associated with increased stroke/TIA risk is controversial and, if it does, which morphological type most predisposes to thrombus formation. We assessed LAA morphology in stroke patients with cryptogenic or suspected cardiogenic etiology and in age- and gender-matched healthy controls. LAA morphology and volume were analyzed by cardiac computed tomography in 111 patients (74 males; mean age 60 ± 11 years) with acute ischemic stroke of cryptogenic or suspected cardiogenic etiology other than known atrial fibrillation (AF). A subgroup of 40 patients was compared to an age- and gender-matched control group of 40 healthy individuals (21 males in each; mean age 54 ± 9 years). LAA was classified into four morphology types (Cactus, ChickenWing, WindSock, CauliFlower) modified with a quantitative qualifier. The proportions of LAA morphology types in the main stroke group, matched stroke subgroup, and control group were as follows: Cactus (9.0%, 5.0%, 20.0%), ChickenWing (23.4%, 37.5%, 10.0%), WindSock (47.7%, 35.0%, 67.5%), and CauliFlower (19.8%, 22.5%, 2.5%). The distribution of morphology types differed significantly (P<0.001) between the matched stroke subgroup and control group. The proportion of single-lobed LAA was significantly higher (P<0.001) in the matched stroke subgroup (55%) than the control group (6%). LAA volumes were significantly larger (P<0.001) in both stroke study groups compared to controls patients. To conclude, LAA morphology differed significantly between stroke patients and controls, and single-lobed LAAs were overrepresented and LAA volume was larger in patients with acute ischemic stroke of cryptogenic or suspected cardiogenic etiology. PMID:25751618

  15. Left atrial appendage morphology in patients with suspected cardiogenic stroke without known atrial fibrillation.

    PubMed

    Korhonen, Miika; Muuronen, Antti; Arponen, Otso; Mustonen, Pirjo; Hedman, Marja; Jäkälä, Pekka; Vanninen, Ritva; Taina, Mikko

    2015-01-01

    The left atrial appendage (LAA) is the typical origin for intracardiac thrombus formation. Whether LAA morphology is associated with increased stroke/TIA risk is controversial and, if it does, which morphological type most predisposes to thrombus formation. We assessed LAA morphology in stroke patients with cryptogenic or suspected cardiogenic etiology and in age- and gender-matched healthy controls. LAA morphology and volume were analyzed by cardiac computed tomography in 111 patients (74 males; mean age 60 ± 11 years) with acute ischemic stroke of cryptogenic or suspected cardiogenic etiology other than known atrial fibrillation (AF). A subgroup of 40 patients was compared to an age- and gender-matched control group of 40 healthy individuals (21 males in each; mean age 54 ± 9 years). LAA was classified into four morphology types (Cactus, ChickenWing, WindSock, CauliFlower) modified with a quantitative qualifier. The proportions of LAA morphology types in the main stroke group, matched stroke subgroup, and control group were as follows: Cactus (9.0%, 5.0%, 20.0%), ChickenWing (23.4%, 37.5%, 10.0%), WindSock (47.7%, 35.0%, 67.5%), and CauliFlower (19.8%, 22.5%, 2.5%). The distribution of morphology types differed significantly (P<0.001) between the matched stroke subgroup and control group. The proportion of single-lobed LAA was significantly higher (P<0.001) in the matched stroke subgroup (55%) than the control group (6%). LAA volumes were significantly larger (P<0.001) in both stroke study groups compared to controls patients. To conclude, LAA morphology differed significantly between stroke patients and controls, and single-lobed LAAs were overrepresented and LAA volume was larger in patients with acute ischemic stroke of cryptogenic or suspected cardiogenic etiology. PMID:25751618

  16. Regional atrial blood flow in dogs. Effect of hypertrophy on coronary flow reserve.

    PubMed Central

    Bauman, R P; Rembert, J C; Greenfield, J C

    1989-01-01

    Little is known regarding regional atrial blood flow responses during varying hemodynamic states in both the normal and hypertrophied atria. This study was undertaken to develop a canine model of chronic atrial hypertrophy and to define in both this group and in normal dogs the regional blood flow response to acute atrial fibrillation and to measure coronary flow reserve. In the 12 dogs with atrial but not ventricular hypertrophy the mean left and right atrial weights were 75 and 47% respectively greater than in the normal group. Blood flow in the normal dogs was less in the appendage than in the non-appendage region for both atria and increased significantly during atrial fibrillation. Similar findings were noted in the hypertrophy group except that during control conditions the left atrial appendage flow was similar to the nonappendage flow. Minimal vascular resistance for the hypertrophy group, 39 +/- 3 was significantly (P less than 0.05) greater when compared to the normal group 28 +/- 2 mmHg/cm3 per min per g. Thus, significant regional blood flow differences occur in both the normal and hypertrophied atria. In addition, atrial hypertrophy does not alter the autoregulatory capacity to the hemodynamic stress of atrial fibrillation but does reduce coronary flow reserve. Images PMID:2523414

  17. 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.

  18. Combined Left Atrial Appendage Closure and Pacemaker Implant through a Single Right Femoral Vein Access.

    PubMed

    Regoli, François; Moccetti, Tiziano; Pasotti, Elena; Auricchio, Angelo; Moccetti, Marco

    2016-08-01

    Left atrial appendage (LAA) closure is indicated in patients with atrial fibrillation (AF) and high bleeding as well as thromboembolic risks. A subgroup of these patients may also present an indication for a single-chamber permanent pacemaker due to symptomatic low-rate AF or when "ablate and pace" strategy is indicated for rate control. A miniaturized wireless transcatheter pacing system (TPS) is now available as a single-chamber permanent pacemaker. This case presents how combined LAA closure and permanent pacemaker implant, by means of TPS, is feasible through a single femoral venous access. PMID:26970532

  19. Catheter-based left atrial appendage occlusion procedure: role of echocardiography.

    PubMed

    Perk, Gila; Biner, Simon; Kronzon, Itzhak; Saric, Muhamed; Chinitz, Larry; Thompson, Keith; Shiota, Takahiro; Hussani, Asma; Lang, Roberto; Siegel, Robert; Kar, Saibal

    2012-02-01

    Atrial fibrillation is a common, clinically significant arrhythmic disorder that results in increased risk of morbidity and mortality in affected patients. Atrial fibrillation is more prevalent among men compared with women and the risk for developing atrial fibrillation increases with advancing age. Ischaemic stroke is the most common clinical manifestation of embolic events from atrial fibrillation. While anticoagulation treatment is the preferred treatment, unfortunately, many patients have contraindications for anticoagulation treatment making this option unavailable to them. Previous data have shown that most thrombi that form in association with non-valvular atrial fibrillation occur in the left atrial appendage (LAA). It has been suggested that isolating the LAA from the body of the left atrium might reduce the risk of embolic events and that LAA obliteration may be a treatment option for patients with atrial fibrillation who are not candidates for anticoagulation treatment. Several procedures have been developed for isolation of the LAA, including surgical procedures as well as catheter-based ones. In this paper, we will review the currently available techniques, emphasizing the catheter-based ones. We will examine the increasing role of real-time three-dimensional transoesophageal echocardiography for appropriate screening and patient selection for these procedures, intra-procedural guidance, and follow-up care. PMID:21903725

  20. Catheter ablation in combination with left atrial appendage closure for atrial fibrillation.

    PubMed

    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. The rapid, irregular, and disordered electrical activity in the atria gives rise to palpitations, fatigue, dyspnea, chest pain and dizziness with or without syncope. Patients with AF have a five-fold higher risk of stroke. 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%. Warfarin therapy has several major disadvantages, however, including bleeding, non-tolerance, interactions with other medications and foods, non-compliance and a narrow therapeutic range. 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. The problems associated with warfarin, combined with the limited efficacy and/or serious side effects associated with other medications used for AF, 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. CA is a well-established treatment for AF symptoms, 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. Since the left atrial appendage (LAA) is the source of thrombi in more than 90% of patients with non-valvular atrial fibrillation, 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 LAA closure device. The WATCHMAN device

  1. [Successful direct thrombin inhibitor treatment of a left atrial appendage thrombus developed under rivaroxaban therapy].

    PubMed

    Szegedi, Nándor; Gellér, László; Tahin, Tamás; Merkely, Béla; Széplaki, Gábor

    2016-01-24

    The authors present the history of a 62-year-old man on continuous rivaroxaban therapy who was scheduled for pulmonary vein isolation due to persistent atrial fibrillation. Preoperative transesophageal echocardiography detected the presence of left atrial appendage thrombus. Thrombophilia tests showed that the patient was heterozygous carrier of the methylene-tetrahydrofolate reductase gene mutation. The authors hypothesized that a direct thrombin inhibitor might exert a more appropriate effect against thrombosis in this case and, therefore, a switch to dabigatran was performed. After two months of anticoagulation with the direct thrombin inhibitor and folic acid supplementation the thrombus resolved. The authors underline that thrombus formation may develop in atrial fibrillation even if the patient is adequately treated with rivaroxaban. This case suggests, that methylene-tetrahydrofolate reductase gene mutation may modulate the efficacy of direct Xa factor inhibitors. According to this case history, dabigatran may be an effective therapeutic option in resolving established thrombus. PMID:26772828

  2. 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

  3. Symptomatic bradycardia caused by premature atrial contractions originating from right atrial appendage.

    PubMed

    Alper, At; Gungor, B; Turkkan, C; Tekkesin, Ai

    2013-05-01

    Premature atrial contraction is a common form of supraventricular arrhythmias. In rare cases, severe symptoms other than palpitation may occur. In this report, we present a patient with symptomatic bradycardia which developed secondary to blocked premature atrial contractions and was successfully treated with radiofrequency ablation. PMID:23840105

  4. Left atrial appendage closure: patient, device and post-procedure drug selection.

    PubMed

    Tzikas, Apostolos; Bergmann, Martin W

    2016-05-17

    Left atrial appendage closure (LAAC), a device-based therapy for stroke prevention in patients with atrial fibrillation, is considered an alternative to oral anticoagulation therapy, particularly for patients at high risk of bleeding. Proof of concept has been demonstrated by the PROTECT AF and PREVAIL trials which evaluated the WATCHMAN device (Boston Scientific, Marlborough, MA, USA) versus warfarin, showing favourable outcome for the device group. The most commonly used devices for LAAC are the WATCHMAN and its successor, the WATCHMAN FLX (Boston Scientific) and the AMPLATZER Cardiac Plug and more recently the AMPLATZER Amulet device (both St. Jude Medical, St. Paul, MN, USA). The procedure is typically performed via a transseptal puncture under fluoroscopic and echocardiographic guidance. Technically, it is considered quite demanding due to the anatomic variability and fragility of the appendage. Careful material manipulation, adequate operator training, and good cardiac imaging and device sizing allow a safe, uneventful procedure. Post-procedure antithrombotic drug selection is based on the patient's history, indication and quality of LAAC. PMID:27174112

  5. Rheological and hemostasiological aspects of thrombus formation in the left atrial appendage in atrial fibrillation? A new strategy for prevention of cardioembolic stroke.

    PubMed

    Leithäuser, Boris; Jung, Friedrich; Park, Jai-Wun

    2010-01-01

    Atrial fibrillation (AF), as the most common cardiac rhythm disturbance, gains in importance not only for the persons affected, but also for health care and social economy due to thromboembolic events, of which stroke is the most serious, disabling, and life threatening one. Cardiac embolism is due to thrombus formation mainly in the left atrial appendage (LAA). The pathophysiology leading to increased thrombogenicity is complex and requires a remodelling of the LAA structure, decreased LAA blood flow, activation of inflammatory processes, deviations of the hemostatic/fibrinolytic system, and activation/dysfunction of endothelial/endocardial cells. Altogether, a prothrombotic state proposed by Virchow more than 150 years ago. The presence of a LAA thrombus, therefore, is a result of a dynamic process of clot formation and lysis. A comprehensive understanding of this pathophysiology is helpful to optimize the management of patients at high risk of cardioembolic stroke. Especially those with contraindications for oral anticoagulation are in a need of an alternative approach that is not associated with a long-term risk of hemorrhage and other attendant circumstances. The reasonable alternative may be the exclusion of the LAA cavity from circulation by either surgical or percutaneous catheter-based procedures. PMID:20675914

  6. Combined catheter ablation for atrial fibrillation and Watchman® left atrial appendage occlusion procedures: Five-year experience

    PubMed Central

    Phillips, Karen P.; Walker, Daniel T.; Humphries, Julie A.

    2015-01-01

    Background Patients with atrial fibrillation (AF) may benefit from undergoing concomitant interventions of left atrial catheter ablation and device occlusion of the left atrial appendage (LAA) as a two-pronged strategy for rhythm control and stroke prevention. We report on the outcome of combined procedures in a single center case series over a 5-year timeframe. Methods Ninety-eight patients with non-valvular AF and a mean CHA2DS2-VASc score 2.6±1.0 underwent either first time, or redo pulmonary vein isolation (PVI) procedures, followed by successful implant of a Watchman® device. Results All procedures were generally uncomplicated with a mean case time of 213±40 min. Complete LAA occlusion was achieved at initial implant in 92 (94%) patients. Satisfactory LAA occlusion was achieved in 100% of patients at 12 months, with a complete LAA occlusion rate of 86%. All patients discontinued oral anticoagulation. Persistent late peri-device leaks were more frequently associated with device angulation or shoulder protrusion, and were associated with a significantly lower achieved device compression of 12±3% vs. 15±5% (p<0.01) than complete occlusion. One ischemic stroke was recorded over a mean follow-up time of 802±439 days. Twelve months׳ freedom from detectable AF was achieved in 77% of patients. Conclusions Combined procedures of catheter ablation for AF and Watchman® LAA implant appear to be feasible and safe, with excellent rates of LAA occlusion achieved and an observed stroke rate of 0.5% per year during mid-term follow-up. Incomplete occlusion was associated with lower achieved device compression and was more frequently associated with suboptimal device position. PMID:27092193

  7. Localized reentry within the left atrial appendage: arrhythmogenic role in patients undergoing ablation of persistent atrial fibrillation

    PubMed Central

    Hocini, Mélèze; Shah, Ashok J.; Nault, Isabelle; Sanders, Prashanthan; Wright, Matthew; Narayan, Sanjiv M.; Takahashi, Yoshihide; Jaïs, Pierre; Matsuo, Seiichiro; Knecht, Sébastien; Sacher, Frédéric; Lim, Kang-Teng; Clémenty, Jacques; Haïssaguerre, Michel

    2012-01-01

    BACKGROUND Left atrial appendage (LAA) is implicated in maintenance of atrial fibrillation (AF) and atrial tachycardia (AT) associated with persistent AF (PsAF) ablation, although little is known about the incidence and mechanism of LAA AT. OBJECTIVE The purpose of this study was to characterize LAA ATs associated with PsAF ablation. METHODS In 74 consecutive patients undergoing stepwise PsAF ablation, 142 ATs were encountered during index and repeat procedures. Out of 78 focal-source ATs diagnosed by activation and entrainment mapping, 15 (19%) arose from the base of LAA. Using a 20-pole catheter, high-density maps were constructed (n = 10; age 57 ± 6 years) to characterize the mechanism of LAA-AT. The LAA orifice was divided into the posterior ridge and anterior-superior and inferior segments to characterize the location of AT. RESULTS Fifteen patients with LAA AT had symptomatic PsAF for 17 ± 15 months before ablation. LAA AT (cycle length [CL] 283 ± 30 ms) occurred during the index procedure in four and after 9 ± 7 months in 11 patients. We could map 89% ± 8% AT CLs locally with favorable entrainment from within the LAA, which is suggestive of localized reentry with centrifugal atrial activation. ATs were localized to inferior segment (n = 4), anterior-superior segment (n = 5), and posterior ridge (n = 6) with 1:1 conduction to the atria. Ablation targeting long fractionated or mid-diastolic electrogram within the LAA resulted in tachycardia termination. Postablation, selective contrast radiography demonstrated atrial synchronous LAA contraction in all but one patient. At 18 ± 7 months, 13/15 (87%) patients remained in sinus rhythm without antiarrhythmic drugs. CONCLUSION LAA is an important source of localized reentrant AT in patients with PsAF at index and repeat ablation procedures. Ablation targeting the site with long fractionated or mid-diastolic LAA electrogram is highly effective in acute and medium-term elimination of the arrhythmia. PMID

  8. Left atrial appendage isolation using percutaneous (endocardial/epicardial) devices: Pre-clinical and clinical experience.

    PubMed

    Romero, Jorge; Natale, Andrea; Engstrom, Krysthel; Di Biase, Luigi

    2016-02-01

    Atrial fibrillation (AF) is the most common arrhythmia in the elderly population and it is associated with a four-fold to five-fold increased risk of thromboembolic events. It was not until the mid-1950s that the left atrial appendage (LAA) was identified as the main location of thrombus formation, particularly in patients with non-valvular AF. In this review, we explain at some extent its embryology, anatomy and physiology, and as well as the clinical and pre-clinical trials published to date testing the safety and efficacy of most LAA closure devices. Among those devices, the most studied include the PLAATO system (ev3 Endovascular, Plymouth, MN), the Amplatzer cardiac plug (St Jude, Golden Valley, MN; St. Jude Medical, Minneapolis, MN), the WATCHMAN device (Boston Scientific, Plymouth, MN; Atritech Inc., Plymouth, MN), and the LARIAT device (SentreHEART, Palo Alto, CA). Similarly, newer LAA closure devices currently under investigation such as the Transcatheter Patch (Custom Medical Devices, Athens, Greece), AEGIS, and the Coherex WaveCrest (Salt Lake City, UT) will also be discussed. Future perspectives and the need for well-designed prospective studies between devices and new oral anticoagulant drugs are also proposed. PMID:26141854

  9. Early Safety and Efficacy of Percutaneous Left Atrial Appendage Suture Ligation

    PubMed Central

    Price, Matthew J.; Gibson, Douglas N.; Yakubov, Steven J.; Schultz, Jason C.; Di Biase, Luigi; Natale, Andrea; Burkhardt, J. David; Pershad, Ashish; Byrne, Timothy J.; Gidney, Brett; Aragon, Joseph R.; Goldstein, Jeffrey; Moulton, Kriegh; Patel, Taral; Knight, Bradley; Lin, Albert C.; Valderrábano, Miguel

    2015-01-01

    BACKGROUND Transcatheter left atrial appendage (LAA) ligation may represent an alternative to oral anticoagulation for stroke prevention in atrial fibrillation.. OBJECTIVES This study sought to assess the early safety and efficacy of transcatheter ligation of the LAA for stroke prevention in atrial fibrillation.. METHODS This was a retrospective, multicenter study of consecutive patients undergoing LAA ligation with the Lariat device at 8 U.S. sites. The primary endpoint was procedural success, defined as device success (suture deployment and <5 mm leak by post-procedure transesophageal echocardiography), and no major complication at discharge (death, myocardial infarction, stroke, Bleeding Academic Research Consortium bleeding type 3 or greater, or cardiac surgery). Post-discharge management was per operator discretion. RESULTS A total of 154 patients were enrolled. Median CHADS2 score (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, prior stroke, transient ischemic attack, or thromboembolism [doubled]) was 3 (interquartile range: 2 to 4). Device success was 94%, and procedural success was 86%. A major complication occurred in 15 patients (9.7%). There were 14 major bleeds (9.1%), driven by the need for transfusion (4.5%). Significant pericardial effusion occurred in 16 patients (10.4%). Follow-up was available in 134 patients at a median of 112 days (interquartile range: 50 to 270 days): Death, myocardial infarction, or stroke occurred in 4 patients (2.9%). Among 63 patients with acute closure and transesophageal echocardiography follow-up, there were 3 thrombi (4.8%) and 13 (20%) with residual leak. CONCLUSIONS In this initial multicenter experience of LAA ligation with the Lariat device, the rate of acute closure was high, but procedural success was limited by bleeding. A prospective randomized trial is required to adequately define clinical efficacy, optimal post-procedure medical therapy, and the effect of operator experience on

  10. [GISE/AIAC position paper on percutaneous left atrial appendage occlusion in patients with nonvalvular atrial fibrillation: recommendations for patient selection, facilities, competences, organizing and training requirements].

    PubMed

    Berti, Sergio; Themistoclakis, Sakis; Santoro, Gennaro; De Ponti, Roberto; Danna, Paolo; Zecchin, Massimo; Bedogni, Francesco; Padeletti, Luigi

    2014-09-01

    Thromboembolism from the left atrial appendage is the most feared complication in patients with atrial fibrillation (AF). The cornerstone for the management of chronic nonvalvular AF is stroke reduction with oral anticoagulation (OAC). However, poor compliance, maintaining a narrow therapeutic window, and major side effects such as bleeding have severely limited its use, creating a therapeutic dilemma. About 20% of AF patients do not receive OAC due to contraindications and less than half of AF patients are not on OAC due to reluctance of the prescribing physician and/or patient non-compliance. Fortunately, over the past decade, the introduction of percutaneous approaches for left atrial appendage occlusion has offered a viable alternative to the management of nonvalvular AF in patients with OAC contraindication. Occlusion devices such as the Amplatzer Cardiac Plug and Watch man device have shown their noninferiority to OAC for stroke prophylaxis with less bleeding complications, while more recently some new devices have been introduced. The aim of this position paper is to review the most relevant clinical aspects of left atrial appendage occlusion from patient selection to periprocedural and follow-up management. In addition, the importance of a medical team and an organizational environment adequate to optimize all the steps of this procedure is discussed. PMID:25298359

  11. Atrial Fibrillation Associated Chromosome 4q25 Variants Are Not Associated with PITX2c Expression in Human Adult Left Atrial Appendages

    PubMed Central

    Gore-Panter, Shamone R.; Hsu, Jeffery; Hanna, Peter; Gillinov, A. Marc; Pettersson, Gosta; Newton, David W.; Moravec, Christine S.; Van Wagoner, David R.; Chung, Mina K.; Barnard, John; Smith, Jonathan D.

    2014-01-01

    Atrial Fibrillation (AF), the most common sustained arrhythmia, has a strong genetic component, but the mechanism by which common genetic variants lead to increased AF susceptibility is unknown. Genome-wide association studies (GWAS) have identified that the single nucleotide polymorphisms (SNPs) most strongly associated with AF are located on chromosome 4q25 in an intergenic region distal to the PITX2 gene. Our objective was to determine whether the AF-associated SNPs on chromosome 4q25 were associated with PITX2c expression in adult human left atrial appendages. Analysis of a lone AF GWAS identified four independent AF risk SNPs at chromosome 4q25. Human adult left atrial appendage tissue was obtained from 239 subjects of European Ancestry and used for SNP analysis of genomic DNA and determination of PITX2c RNA expression levels by quantitative PCR. Subjects were divided into three groups based on their history of AF and pre-operative rhythm. AF rhythm subjects had higher PITX2c expression than those with history of AF but in sinus rhythm. PITX2c expression was not associated with the AF risk SNPs in human adult left atrial appendages in all subjects combined or in each of the three subgroups. However, we identified seven SNPs modestly associated with PITX2c expression located in the introns of the ENPEP gene, ∼54 kb proximal to PITX2. PITX2c expression in human adult left atrial appendages is not associated with the chromosome 4q25 AF risk SNPs; thus, the mechanism by which these SNPs are associated with AF remains enigmatic. PMID:24465984

  12. 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. PMID:25709379

  13. [ANMCO/AIAC/SICI-GISE/SIC/SICCH Consensus document: Percutaneous left atrial appendage occlusion in patients with nonvalvular atrial fibrillation: indications, patient selection, competences, organization, and operator training].

    PubMed

    Casu, Gavino; Gulizia, Michele Massimo; Molon, Giulio; Mazzone, Patrizio; Audo, Andrea; Casolo, Giancarlo; Di Lorenzo, Emilio; Portoghese, Michele; Pristipino, Christian; Ricci, Renato Pietro; Themistoclakis, Sakis; Padeletti, Luigi; Tondo, Claudio; Berti, Sergio; Oreglia, Jacopo Andrea; Gerosa, Gino; Zanobini, Marco; Ussia, Gian Paolo; Musumeci, Giuseppe; Romeo, Francesco; Di Bartolomeo, Roberto

    2016-01-01

    Atrial fibrillation (AF) is the most common arrhythmia and its prevalence is increasing due to the progressive aging of the population. About 20% of strokes are attributable to AF and AF patients are at 5-fold increased risk of stroke. The mainstay of treatment of AF is the prevention of thromboembolic complications with oral anticoagulation therapy. Drug treatment for many years has been based on the use of vitamin K antagonists, but recently newer and safer molecules have been introduced (dabigatran etexilate, rivaroxaban, apixaban and edoxaban). Despite these advances, many patients still do not receive adequate anticoagulation therapy because of contraindications (relative and absolute) to this treatment. Over the last decade, percutaneous closure of left atrial appendage, main site of thrombus formation during AF, proved effective in reducing thromboembolic complications, thus offering a valid medical treatment especially in patients at increased bleeding risk. The aim of this consensus document is to review the main aspects of left atrial appendage occlusion (selection and multidisciplinary assessment of patients, currently available methods and devices, requirements for centers and operators, associated therapies and follow-up modalities) having as a ground the significant evolution of techniques and the available relevant clinical data. PMID:27571335

  14. Application of an Epicardial Left Atrial Appendage Occlusion Device by a Robotic-Assisted, Right Chest Approach.

    PubMed

    Lewis, Clifton T P; Stephens, Richard L; Horst, Vernon D; Angelillo, Margaret; Tyndal, Charles M

    2016-05-01

    Closure of the left atrial appendage (LAA) has become a standard part of any mitral valve operation because it is thought to reduce the potential for late thrombus development and for embolic events. To date, surgeons performing robotic mitral valve operations have been limited to an endocardial approach to LAA closure. However, oversewing the orifice of the LAA is time consuming and lengthens the cross-clamp time, and failures to obtain permanent closure have been reported. We describe our technique for an epicardial approach that is safe and efficient and that gives a secure closure of the LAA. PMID:27106473

  15. Early operative comparison of two epicardial left atrial appendage occluding systems applied during off-pump coronary revascularisation in patients with persistent atrial fibrillation

    PubMed Central

    Emery, Robert; Gryszko, Leszek; Kaczejko, Kamil; Żegadło, Arkadiusz; Frankowska, Emilia; Mróz, Jakub; Skrobowski, Andrzej

    2016-01-01

    Introduction Atrial fibrillation (AF) increases long-term mortality and stroke rate in patients having coronary artery bypass grafting (CABG). Because oral anticoagulation (OAC) is associated with both a significant incidence of discontinuation and well known complication rates, left atrial appendage occlusion might be beneficial for stroke prevention. This study presents the first clinical and practical comparison of two epicardial left appendage occluders (LAAO) accruing experience in application during off-pump coronary revascularisation in patients with persistent AF. Material and methods Fifteen consecutive patients with persistent AF were assigned to intraoperative LAA occlusion with either TigerPaw System II (n = 8) or AtriClip (n = 7) device during off-pump CABG and concomitant left atrial epicardial ablation. Both systems were analysed in terms of ease and safety of application along with intraoperative LAA occlusion success. Results Surgical risk was increased in the study population (mean EuroScore II: 3.2 ± 0.3%). In all patients in the AtriClip group successful off-pump LAA occlusion confirmed by intraoperative transoesophageal echocardiography was achieved. The TigerPaw application was quicker and easier, but in 2 patients it was unsuccessful. During the hospital stay there were no bleeding or thromboembolic events recorded. Conclusions In a pilot cohort epicardial LAAO during off-pump CABG in patients with persistent AF was performed safely and successfully with an AtriClip device. The TigerPaw System requires technological improvement. It might be useful to adapt the use of the type of occluding device to the LAA morphologic type and target revascularisation vessels to avoid the additional use of a heart positioner or obviate coronary compression.

  16. 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. PMID:27516032

  17. Implant success and safety of left atrial appendage closure with the WATCHMAN device: peri-procedural outcomes from the EWOLUTION registry

    PubMed Central

    Boersma, Lucas V.A.; Schmidt, Boris; Betts, Timothy R.; Sievert, Horst; Tamburino, Corrado; Teiger, Emmanuel; Pokushalov, Evgeny; Kische, Stephan; Schmitz, Thomas; Stein, Kenneth M.; Bergmann, Martin W.

    2016-01-01

    Aims Left atrial appendage closure is a non-pharmacological alternative for stroke prevention in high-risk patients with non-valvular atrial fibrillation. The objective of the multicentre EWOLUTION registry was to obtain clinical data on procedural success and complications, and long-term patient outcomes, including bleeding and incidence of stroke/transient ischaemic attack (TIA). Here, we report on the peri-procedural outcomes of up to 30 days. Methods and results Baseline/implant data are available for 1021 subjects. Subjects in the study were at high risk of stroke (average CHADS2 score: 2.8 ± 1.3, CHA2DS2-VASc: 4.5 ± 1.6) and moderate-to-high risk of bleeding (average HAS-BLED score: 2.3 ± 1.2). Almost half of the subjects (45.4%) had a history of TIA, ischaemic stroke, or haemorrhagic stroke; 62% of patients were deemed unsuitable for novel oral anticoagulant by their physician. The device was successfully deployed in 98.5% of patients with no flow or minimal residual flow achieved in 99.3% of implanted patients. Twenty-eight subjects experienced 31 serious adverse events (SAEs) within 1 day of the procedure. The overall 30-day mortality rate was 0.7%. The most common SAE occurring within 30 days of the procedure was major bleeding requiring transfusion. Incidence of SAEs within 30 days was significantly lower for subjects deemed to be ineligible for oral anticoagulation therapy (OAT) compared with those eligible for OAT (6.5 vs. 10.2%, P = 0.042). Conclusion Left atrial appendage closure with the WATCHMAN device has a high success rate in complete LAAC with low peri-procedural risk, even in a population with a higher risk of stroke and bleeding, and multiple co-morbidities. Improvement in implantation techniques has led to a reduction of peri-procedural complications previously limiting the net clinical benefit of the procedure. PMID:26822918

  18. Comparative expression profiles of microRNA in left and right atrial appendages from patients with rheumatic mitral valve disease exhibiting sinus rhythm or atrial fibrillation

    PubMed Central

    2014-01-01

    Background The atrial fibrillation (AF) associated microRNAs (miRNAs) were found in the right atrium (RA) and left atrium (LA) from patients with rheumatic mitral valve disease (RMVD). However, most studies only focus on the RA; and the potential differences of AF-associated miRNAs between the RA and LA are still unknown. The aim of this study was to perform miRNA expression profiles analysis to compare the potential differences of AF-associated miRNAs in the right atrial appendages (RAA) and left atrial appendages (LAA) from RMVD patients. Methods Samples tissues from the RAA and LAA were obtained from 18 RMVD patients (10 with AF) during mitral valve replacement surgery. From these tissues, miRNA expression profiles were created and analyzed using a human miRNA microarray. Then, the results were validated using qRT-PCR analysis for 12 selected miRNAs. Finally, potential targets of 10 validated miRNAs were predicted and their functions and potential pathways were analyzed using the miRFocus database. Results In RAA, 65 AF-associated miRNAs were found and significantly dysregulated (i.e. 28 miRNAs were up-regulated and 37 were down-regulated). In LAA, 42 AF-associated miRNAs were found and significantly dysregulated (i.e. 22 miRNAs were up-regulated and 20 were down-regulated). Among these AF-associated miRNAs, 23 of them were found in both RAA and LAA, 45 of them were found only in RAA, and 19 of them were found only in LAA. Finally, 10 AF-associated miRNAs validated by qRT-PCR were similarly distributed in RAA and LAA; 3 were found in both RAA and LAA, 5 were found only in RAA, and 2 were found only in LAA. Potential miRNA targets and molecular pathways were identified. Conclusions We have found the different distributions of AF-associated miRNAs in the RAA and LAA from RMVD patients. This may reflect different miRNA mechanisms in AF between the RA and LA. These findings may provide new insights into the underlying mechanisms of AF in RMVD patients. PMID:24708751

  19. Percutaneous left atrial appendage occlusion – treatment outcomes and 6 months of follow-up – a single-center experience

    PubMed Central

    Karczewski, Michał; Skowronek, Radomir; Burysz, Marian; Fischer, Marcin; Anisimowicz, Lech; Demkow, Marcin; Konka, Marek; Ogorzeja, Wojciech

    2016-01-01

    Aim To present the results of treatment and evaluate 6 months of follow-up in a group of patients with non-valvular atrial fibrillation, who underwent the procedure of percutaneous left atrial appendage occlusion (PLAAO). Material and methods Percutaneous left atrial appendage occlusion was performed in 34 patients with non-valvular atrial fibrillation and contraindications for oral anticoagulation therapy. The risk of thromboembolic and bleeding complications was determined based on the CHA2DS2VASc and HAS-BLED scales. The Amplatzer Amulet system from St. Jude Medical was used. On the first postoperative day, all patients were started on double antiplatelet therapy with 75 mg/day of acetylsalicylic acid (ASA) and 75 mg/day of clopidogrel (CLO). On the 30th postoperative day, the efficacy of the antiplatelet therapy was assessed with impedance aggregometry using a Multiplate analyzer (Roche). Echocardiographic examinations were performed intraoperatively and on the first postoperative day; subsequently, follow-up examinations were conducted 1 and 6 months after the implantation. Results In all patients, proper occluder position was observed throughout the follow-up. No leakage or thrombi around the implants were found. No strokes or bleeding complications associated with the antiplatelet therapy were observed. Multiplate assessment of platelet activity was conducted in 20 out of 34 patients. The efficacy of ASA treatment was demonstrated in all patients; no response to clopidogrel treatment was observed in 5 out of 20 patients. One patient suffered from cardiac tamponade, which required the performance of full sternotomy. Local complications (hematomas of the inguinal region) were observed in 3 patients. One of the patients died for reasons unrelated to the procedure. Conclusions Percutaneous left atrial appendage occlusion is an effective procedure in patients with non-valvular atrial fibrillation and contraindications for chronic anticoagulation therapy. Further

  20. A low-dose, dual-phase cardiovascular CT protocol to assess left atrial appendage anatomy and exclude thrombus prior to left atrial intervention.

    PubMed

    Lazoura, Olga; Ismail, Tevfik F; Pavitt, Christopher; Lindsay, Alistair; Sriharan, Mona; Rubens, Michael; Padley, Simon; Duncan, Alison; Wong, Tom; Nicol, Edward

    2016-02-01

    Assessment of the left atrial appendage (LAA) for thrombus and anatomy is important prior to atrial fibrillation (AF) ablation and LAA exclusion. The use of cardiovascular CT (CCT) to detect LAA thrombus has been limited by the high incidence of pseudothrombus on single-pass studies. We evaluated the diagnostic accuracy of a two-phase protocol incorporating a limited low-dose delayed contrast-enhanced examination of the LAA, compared with a single-pass study for LAA morphological assessment, and transesophageal echocardiography (TEE) for the exclusion of thrombus. Consecutive patients (n = 122) undergoing left atrial interventions for AF were assessed. All had a two-phase CCT protocol (first-past scan plus a limited, 60-s delayed scan of the LAA) and TEE. Sensitivity, specificity, diagnostic accuracy, positive (PPV) and negative predictive values (NPV) were calculated for the detection of true thrombus on first-pass and delayed scans, using TEE as the gold standard. Overall, 20/122 (16.4 %) patients had filling defects on the first-pass study. All affected the full delineation of the LAA morphology; 17/20 (85 %) were confirmed as pseudo-filling defects. Three (15 %) were seen on late-pass and confirmed as true thrombi on TEE; a significant improvement in diagnostic performance relative to a single-pass scan (McNemar Chi-square 17, p < 0.001). The sensitivity, specificity, diagnostic accuracy, PPV and NPV was 100, 85.7, 86.1, 15.0 and 100 % respectively for first-pass scans, and 100 % for all parameters for the delayed scans. The median (range) additional radiation dose for the delayed scan was 0.4 (0.2-0.6) mSv. A low-dose delayed scan significantly improves the identification of true LAA anatomy and thrombus in patients undergoing LA intervention. PMID:26420491

  1. Effectiveness of Integrating Delayed Computed Tomography Angiography Imaging for Left Atrial Appendage Thrombus Exclusion into the Care of Patients Undergoing Ablation of Atrial Fibrillation

    PubMed Central

    Bilchick, Kenneth C.; Mealor, Augustus; Gonzalez, Jorge; Norton, Patrick; Zhuo, David; Mason, Pamela; Ferguson, John D.; Malhotra, Rohit; Mangrum, J. Michael; Darby, Andrew E.; DiMarco, John; Hagspiel, Klaus; Dent, John; Kramer, Christopher M.; Stukenborg, George J.; Salerno, Michael

    2015-01-01

    Background Computed tomography angiography (CTA) can identify and rule out left atrial appendage (LAA) thrombus when delayed imaging is also performed. Objective In patients referred for CTA for pulmonary vein anatomy prior to ablation of atrial fibrillation or atypical left atrial flutter (AF), we sought to determine the effectiveness of a novel clinical protocol for integrating results of CTA delayed imaging of the LAA into pre-procedure care. Methods After making delayed imaging of the LAA part of our routine pre-ablation CTA protocol, we integrated early reporting of pre-ablation CTA LAA imaging results into clinical practice as part of a formal protocol in June 2013. We then analyzed the effectiveness of this protocol by evaluating 320 AF ablation patients with CTA imaging during 2012–2014. Results Among CTA patients with delayed LAA imaging, the sensitivity and negative predictive values for LAA thrombus with intracardiac echocardiography (ICE) or transesophageal echocardiograms (TEEs) as the reference standard were both 100%. ICE during ablation confirmed absence of thrombus in patients with a negative CTA or negative TEE. No patients with either a negative CTA or an equivocal CTA combined with a negative TEE had strokes or transient ischemic attacks. Overall, the need for TEEs decreased from 57.5% to 24.0% during the 3-year period as a result of the CTA protocol. Conclusions Clinical integration of CTA with delayed LAA imaging into the care of patients having catheter ablation of AF is feasible, safe, and effective. Such a protocol could be applied broadly to improve patient care. PMID:26341605

  2. Urgent resection of a giant left atrial appendage aneurysm and mitral valve replacement in a complex case of Hurler-Scheie syndrome.

    PubMed

    Brazier, Andrew; Hasan, Ragheb; Jenkins, Petra; Hoschtitzky, Andreas

    2015-01-01

    Hurler-Scheie syndrome is a rare lysosomal storage disease affecting the cardiovascular system. Besides the cardiac manifestations, it presents with complications from abnormal proteoglycan deposition in soft tissues in many locations, resulting in joint contractures, paraplegia, impaired vision, airway narrowing and restrictive lung function, to name a few. There are very few reports of surgical management of valvular heart disease due to mucopolysaccharidosis (MPS). We describe the successful management of a patient with an extremely challenging case of mitral valve stenosis and a giant left atrial appendage aneurysm due to MPS type 1 (Hurler-Scheie syndrome). The patient underwent mitral valve replacement and excision of the giant left atrial appendage aneurysm; a similar case has not been previously reported. PMID:26546621

  3. Concentrations of fusidic acid, cloxacillin, and cefamandole in sera and atrial appendages of patients undergoing cardiac surgery.

    PubMed Central

    Bergeron, M G; Desaulniers, D; Lessard, C; Lemieux, M; Després, J P; Métras, J; Raymond, G; Brochu, G

    1985-01-01

    The concentrations of cefamandole, cloxacillin and fusicid acid were measured in the serum and heart tissue of 100 recipients of these drugs before cardiac surgery. During cardiopulmonary bypass, mean (+/- standard deviation) peak concentrations in serum of all patients were 63.0 +/- 34.0 micrograms of cefamandole per ml, 30.8 +/- 17.7 micrograms of cloxacillin per ml, and 32.4 +/- 10.8 micrograms of fusidic acid per ml. Mean (+/- standard deviation) concentrations in atrial appendages taken 1 h (+/- 15 min) after infusion were 21.3 +/- 11.0 micrograms of cefamandole per g, 23.8 +/- 17.3 micrograms of cloxacillin per g, and 10.7 +/- 4.2 micrograms of fusidic acid per g. No cloxacillin could be detected in 5 of 39 heart specimens. Mean tissue-to-serum ratios at 1 h for cefamandole, cloxacillin, and fusidic acid were respectively 0.35, 0.73, and 0.33. Fusidic acid, a drug which is highly effective in vitro against both methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis, was detectable in heart tissue in concentrations which were 12 times higher than the MICs of this agent against these resistant microorganisms. PMID:4026265

  4. Left atrial appendage closure-indications, techniques, and outcomes: results of the European Heart Rhythm Association Survey.

    PubMed

    Pison, Laurent; Potpara, Tatjana S; Chen, Jian; Larsen, Torben B; Bongiorni, Maria Grazia; Blomström-Lundqvist, Carina

    2015-04-01

    The purpose of this EP Wire was to assess the indications, techniques, and outcomes of left atrial appendage occlusion (LAAO) in Europe. Thirty-three European centres, all members of the European Heart Rhythm Association electrophysiology (EP) research network, responded to this survey by completing the questionnaire. The major indication for LAAO (94%) was the prevention of stroke in patients at high thrombo-embolic risk (CHA2DS2-VASc ≥ 2) and contraindications to oral anticoagulants (OACs). Twenty-one (64%) of the responding centres perform LAAO in their own institution and 80% implanted 30 or less LAAO devices in 2014. Two-dimensional transoesophageal echocardiography was the preferred imaging technique to visualize LAA before, during, and after LAAO in 79, 58, and 62% of the participating centres, respectively. Following LAAO, 49% of the centres prescribe vitamin K antagonists or novel OACs. Twenty-five per cent of the centres combine LAAO with pulmonary vein isolation. The periprocedural complications included death (range, 0-3%), ischaemic or haemorrhagic stroke (0-25%), tamponade (0-25%), and device embolization (0-20%). In conclusion, this EP Wire has demonstrated that LAAO is most commonly employed in patients at high thrombo-embolic risk in whom OAC is contraindicated. The technique is not yet very widespread and the complication rates remain significant. PMID:25833883

  5. 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

  6. Assessment of Device-Related Thrombus and Associated Clinical Outcomes With the WATCHMAN Left Atrial Appendage Closure Device for Embolic Protection in Patients With Atrial Fibrillation (from the PROTECT-AF Trial).

    PubMed

    Main, Michael L; Fan, Dali; Reddy, Vivek Y; Holmes, David R; Gordon, Nicole T; Coggins, Tina R; House, John A; Liao, Lawrence; Rabineau, Dawn; Latus, George G; Huber, Kenneth C; Sievert, Horst; Wright, Richard F; Doshi, Shephal K; Douglas, Pamela S

    2016-04-01

    Left atrial appendage closure with the WATCHMAN device is an alternative to anticoagulation for stroke prevention in selected patients with atrial fibrillation (AF). LA device-related thrombus (DRT) is poorly defined and understood. We aimed to (1) develop consensus echocardiographic diagnostic criteria for DRT; (2) estimate the incidence of DRT; and (3) determine clinical event rates in patients with DRT. In phase 1 (training), a training manual was developed and reviewed by 3 echocardiographers with left atrial appendage closure device experience. All available transesophageal (TEE) studies in the WATCHMAN left atrial appendage system for embolic protection in patients with atrial fibrillation (PROTECT-AF) trial patients with suspected DRT were reviewed in 2 subsequent phases. In phase 2 (primary blind read), each reviewer independently scored each study for DRT, and final echo criteria were developed. Unanimously scored studies were considered adjudicated, whereas all others were reevaluated by all reviewers in phase 3 (group adjudication read). DRT was suspected in 35 of 485 patients by the site investigator, the echocardiography core laboratory, or both; 93 of the individual TEE studies were available for review. In phase 2, 3 readers agreed on 67 (72%) of time points. Based on phases 1 and 2, 5 DRT criteria were developed. In phase 3, studies without agreement in phase 2 were adjudicated using these criteria. Overall, at least 1 TEE was DRT positive in 27 (5.7%) PROTECT-AF patients. Stroke, peripheral embolism, or cardiac/unexplained death occurred in subjects with DRT at a rate of 3.4 per 100 patient-years follow-up. In conclusion, DRT were identified on at least 1 TEE in 27 PROTECT-AF patients, indicating a DRT incidence of 5.7%. Primary efficacy events in patients with DRT occurred at a rate of 3.4 per 100 patient-years follow-up, intermediate in frequency between event rates previously reported for the overall device and warfarin arms in PROTECT-AF. PMID

  7. Comparison of Efficacy and Safety of Left Atrial Appendage Occlusion in Patients Aged <75 to ≥ 75 Years.

    PubMed

    Freixa, Xavier; Gafoor, Sameer; Regueiro, Ander; Cruz-Gonzalez, Ignacio; Shakir, Samera; Omran, Heyder; Berti, Sergio; Santoro, Gennaro; Kefer, Joelle; Landmesser, Ulf; Nielsen-Kudsk, Jens Erik; Sievert, Horst; Kanagaratnam, Prapa; Nietlispach, Fabian; Gloekler, Steffen; Aminian, Adel; Danna, Paolo; Rezzaghi, Marco; Stock, Friederike; Stolcova, Miroslava; Costa, Marco; Ibrahim, Reda; Schillinger, Wolfgang; Park, Jai-Wun; Meier, Bernhard; Tzikas, Apostolos

    2016-01-01

    Left atrial appendage occlusion (LAAO) is emerging as a promising alternative to oral anticoagulation. Because aged patients present a greater risk of not only cardioembolic events but also major bleeding, LAAO might represent a valid alternative as this would allow oral anticoagulation cessation while keeping cardioembolic protection. The objective of the study was to explore the safety and efficacy of LAAO in elderly patients. Data from the AMPLATZER Cardiac Plug multicenter registry were analyzed. The cohort was categorized in 2 groups (<75 vs ≥ 75 years). A total of 1,053 subjects were included in the registry. Of them, 219 were excluded because of combined procedures. As a result, 828 subjects were included (54.6% ≥ 75 years). Procedural success was high and similar in both groups (97.3%). Acute procedural major adverse events were not statistically different among groups (3.2% in <75 years vs 5.1%; p = 0.17) although stratified analysis showed a higher incidence of cardiac tamponade in elderly patients (0.5% vs 2.2%; p = 0.04). With a median follow-up of 16.8 months, no significant differences in stroke/TIA (1.9% vs 2.3%; p = 0.89) and major bleeding (1.7% vs 2.6%; p = 0.54) were observed. In conclusion, LAAO was associated with similar procedural success in patients aged <75 and ≥ 75 years although older patients had a higher incidence of cardiac tamponade. At follow-up, stroke and major bleeding rates were similar among groups. PMID:26552507

  8. 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

  9. Quantitative Evaluation of the Substantially Variable Morphology and Function of the Left Atrial Appendage and Its Relation with Adjacent Structures

    PubMed Central

    Liu, Xiao-Wei; Fan, Qiong-Ying; Zhang, Xue-Jing; Liu, Guo-Chao; Yang, Hai-Qing; Feng, Ping-Yong; Wang, Yong; Song, Peng

    2015-01-01

    Objective To investigate quantitatively the morphology, anatomy and function of the left atrial appendage (LAA) and its relation with adjacent structures. Materials and Methods A total of 860 patients (533 men, 62.0%, age 55.9±10.4 year) who had cardiac multidetector computed tomography angiography from May to October 2012 were enrolled for analysis. Results Seven types and 6 subtypes of LAA morphology were found with Type 2 being the most prevalent. Type 5 was more significantly (P<0.05) present in women (8.0%) than in men (4.2%). LAA orifice was oval in 81.5%, triangular in 7.3%, semicircular in 4%, water drop-like in 3.2%, round in 2.4% and foot-like in 1.6%. The LAA orifice had a significantly greater (P<0.01) major axis in men (24.79±3.81) than in women (22.68±4.07). The LAA orifice long axis was significantly (P<0.05) positively correlated with the height, weight and surface area of the patient. The LAA morphology parameters displayed strong positive correlation with the left atrium volume, aortic cross area long axis or LSPV long axis but poor correlation with the height, weight, surface area and vertebral body height of the patients. Four types of LAA ridge were identified: AI, AII, B and C with the distribution of 17.6%, 69.9%, 5.9% and 6.6%, respectively. The LAA had a significantly (P<0.05) greater distance from its orifice to the mitral ring in women than in men. The LAA had two filling and two emptying processes with the greatest volume at 45% phase but the least volume at 5% phase. The LAA maximal, minimal and emptying volumes were all significantly (P<0.05) positively correlated with the body height, weight and surface area, whereas the LAA ejection fraction had an inverse correlation with the LAA minimal volume but no correlation with the maximal volume. Conclusion The LAA has substantially variable morphologies and relation with the adjacent structures, which may be helpful in guiding the LAA trans-catheter occlusion or catheter ablation

  10. Morphological and Volumetric Analysis of Left Atrial Appendage and Left Atrium: Cardiac Computed Tomography-Based Reproducibility Assessment

    PubMed Central

    Taina, Mikko; Korhonen, Miika; Haataja, Mika; Muuronen, Antti; Arponen, Otso; Hedman, Marja; Jäkälä, Pekka; Sipola, Petri; Mustonen, Pirjo; Vanninen, Ritva

    2014-01-01

    Objectives Left atrial appendage (LAA) dilatation and morphology may influence an individual's risk for intracardiac thrombi and ischemic stroke. LAA size and morphology can be evaluated using cardiac computed tomography (cCT). The present study evaluated the reproducibility of LAA volume and morphology assessments. Methods A total of 149 patients (47 females; mean age 60.9±10.6 years) with suspected cardioembolic stroke/transient ischemic attack underwent cCT. Image quality was rated based on four categories. Ten patients were selected from each image quality category (N = 40) for volumetric reproducibility analysis by two individual readers. LAA and left atrium (LA) volume were measured in both two-chamber (2CV) and transversal view (TV) orientation. Intertechnique reproducibility was assessed between 2CV and TV (200 measurement pairs). LAA morphology (A = Cactus, B = ChickenWing, C = WindSock, D = CauliFlower), LAA opening height, number of LAA lobes, trabeculation, and orientation of the LAA tip was analysed in all study subjects by three individual readers (447 interobserver measurement pairs). The reproducibility of volume measurements was assessed by intra-class correlation (ICC) and the reproducibility of LAA morphology assessments by Cohen's kappa. Results The intra-observer and interobserver reproducibility of LAA and LA volume measurements was excellent (ICCs>0.9). The LAA (ICC = 0.954) and LA (ICC = 0.945) volume measurements were comparable between 2CV and TV. Morphological classification (ĸ = 0.24) and assessments of LAA opening height (ĸ = 0.1), number of LAA lobes (ĸ = 0.16), trabeculation (ĸ = 0.15), and orientation of the LAA tip (ĸ = 0.37) was only slightly to fairly reproducible. Conclusions LA and LAA volume measurements on cCT provide excellent reproducibility, whereas visual assessment of LAA morphological features is challenging and results in unsatisfactory agreement between readers

  11. Mean platelet volume is associated with the presence of left atrial stasis in patients with non-valvular atrial fibrillation

    PubMed Central

    2013-01-01

    Background Mean platelet volume has been associated with stroke in patients with atrial fibrillation. However, its role as a predictor of left atrial stasis, assessed by transesophageal echocardiography, in patients with non-valvular atrial fibrillation has not yet been clarified. Methods Single center cross-sectional study comprising 427 patients admitted to the emergency department due to symptomatic atrial fibrillation and undergoing transesophageal echocardiogram evaluation for exclusion of left atrial appendage thrombus before cardioversion. All patients had a complete blood count performed in the 12 hours prior to transesophageal echocardiogram. Markers of left atrial stasis were sought: left atrial appendage thrombus, dense spontaneous echocardiographic contrast and low flow velocities in the left atrial appendage. The presence of at least one of the former markers of left atrial stasis was designated left atrial abnormality. Binary logistic multivariate analysis was used for obtaining models for the prediction of transesophageal echocardiogram endpoints. Results Left atrial appendage thrombus was found in 12.2%, dense spontaneous echocardiographic contrast in 29.7%, low flow velocities in 15.3% and left atrial abnormality in 34.2%. Mean platelet volume (exp β = 3.41 p = 0.048) alongside with previous stroke or transient ischemic attack (exp β = 5.35 p = 0.005) and troponin I (exp β = 5.07 p = 0.041) were independent predictors of left atrial appendage thrombus. Mean platelet volume was also incorporated in the predictive models of dense spontaneous echocardiographic contrast, low flow velocities and left atrial abnormality, adding predictive value to clinical, echocardiographic and laboratory variables. Conclusions These findings suggest that mean platelet volume may be associated with the presence of markers of left atrial stasis, reinforcing a likely cardioembolic mechanism for its association with stroke in patients with non

  12. Dependence of aortic arch morphogenesis on intracardiac blood flow in the left atrial ligated chick embryo.

    PubMed

    Hu, Norman; Christensen, Douglas A; Agrawal, Amit K; Beaumont, Charity; Clark, Edward B; Hawkins, John A

    2009-05-01

    Partial left atrial ligation before cardiac septation redistributes intracardiac blood flow and produces left ventricular hypoplasia in the chick. We hypothesized that redistributed intracardiac blood flow adversely alters aortic arch development. We ligated the left atrial appendage with a 10-0 nylon suture at stage 21 chick embryos, then reincubated up to stage 34. Sham embryos had a suture tied adjacent to the atrial wall, and normal controls were unoperated. We measured simultaneous atrioventricular (AV) and dorsal aortic (DAo) blood velocities from stage 24 embryos with an ultrasound pulsed-Doppler flow meter; and the left and right third and fourth aortic arch blood flow with a laser-Doppler flow meter. Ventricular and atrial cross-sectional areas were measured from sequential video fields for planimetry. Intracardiac flow patterns were imaged on video by injecting India ink into the vitelline vein. In separate embryos, radiopaque microfil was injected into the cardiovascular system for micro-CT scanning. We analyzed the morphologic characteristics of the heart at stage 34. Active AV and DAo stroke volume (mm(3)), right third and fourth aortic arch blood flow (mm(3)/s) were all decreased in ligated embryos (P < 0.05) when compared with normal and sham embryos. Ventricular end-diastolic volume versus normal and sham embryos decreased by 45% and 46%, respectively (P < 0.05). India ink injection revealed altered right aortic arch flow patterns in the ligated embryos compared with normal embryos. micro-CT imaging confirmed altered arch morphogenesis. Alterations in intracardiac blood flow disrupt both early cardiac morphogenesis and aortic arch selection. PMID:19322826

  13. Video-assisted thoracoscopic surgery atrial clipping for atrial fibrillation.

    PubMed

    Mithiran, Harish; Sule, Jai; Sazzad, Faizus; Ong, Yilin; Kah Ti, Lian; Kofidis, Theo

    2016-05-01

    The majority of thrombi that arise due to atrial fibrillation occur in the left atrial appendage. Eliminating this cul-de-sac within the left atrium reduces the risk of stroke in these patients. We present a unique case of left atrial appendage occlusion performed via video-assisted thoracoscopic surgery, using an Atriclip to occlude the left atrial appendage in a patient with atrial fibrillation in whom anticoagulation was contraindicated due to a history of recurrent upper gastrointestinal bleeding. PMID:25504982

  14. 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

  15. Stand-alone totally thoracoscopic left atrial appendage exclusion using a novel clipping system in patients with high risk of stroke – initial experience and literature review

    PubMed Central

    Suwalski, Piotr; Drobiński, Dominik; Rozbicka, Joanna; Sypuła, Sławomir; Liszka, Irena; Smoczyński, Radosław; Staromłyński, Jakub; Walecka, Irena; Kosior, Dariusz

    2015-01-01

    Introduction Atrial fibrillation (AF) is the most common clinically relevant arrhythmia and it is strongly associated with stroke. Left atrial appendage (LAA) is considered to be the most often source of thrombotic material. In recent decades a number surgical, percutaneous and hybrid approaches for LAA occlusion have been described revealing very different level of success and showing a variety of challenges associated with this matter. We present the first Polish experience with the stand-alone totally thoracoscopic LAA exclusion using novel clipping system. Material and methods Four patients (one male) in mean age of 74 (± 13) years with long-standing persistent and chronic AF were admitted for totally thoracoscopic LAA exclusion. All patients had significant comorbidities and the history of the oral anticoagulation intolerance or suboptimal/unstable level (CHA2DS2-VASC > 5, HAS_BLED > 3). Three procedures were performed through totally thoracoscopic access. In one patient due to massive adhesions in the left pleura we performed minithoracotomy in fourth left intercostal space. In two months follow-up we observed no mortality, no strokes and no bleedings. Results In all patient total exclusion of LAA with no residual remnant was confirmed. The “skin-to-skin” procedural time took on average 40, minimum 20 minutes. Patients were extubated directly or within two hours after procedure. All patients were discharged early in a good condition. Conclusions Our initial first experience with the novel totally thoracoscopic clipping system for stand-alone LAA exclusion is very promising showing very high efficacy and good safety profile. PMID:26855643

  16. Dynamic cycling in atrial size and flow during obstructive apnoea

    PubMed Central

    Pressman, Gregg S; Cepeda-Valery, Beatriz; Codolosa, Nicolas; Orban, Marek; Samuel, Solomon P; Somers, Virend K

    2016-01-01

    Objective Obstructive sleep apnoea (OSA) is strongly associated with cardiovascular disease. However, acute cardiovascular effects of repetitive airway obstruction are poorly understood. While past research used a sustained Mueller manoeuver to simulate OSA we employed a series of gasping efforts to better simulate true obstructive apnoeas. This report describes acute changes in cardiac anatomy and flow related to sudden changes in intrathoracic pressure. Methods and results 26 healthy, normal weight participants performed 5–6 gasping efforts (target intrathoracic pressure −40 mm Hg) while undergoing Doppler echocardiography. 14 participants had sufficient echocardiographic images to allow comparison of atrial areas during the manoeuver with baseline measurements. Mitral and tricuspid E-wave and A-wave velocities postmanoeuver were compared with baseline in all participants. Average atrial areas changed little during the manoeuver, but variance in both atrial areas was significantly greater than baseline. Further, an inverse relationship was noted with left atrial collapse and right atrial enlargement at onset of inspiratory effort. Significant inverse changes were noted in Doppler flow when comparing the first beat postmanoeuver (pMM1) with baseline. Mitral E-wave velocity increased 9.1 cm/s while tricuspid E-wave velocity decreased 7.0 cm/s; by the eighth beat postmanoeuver (pMM8) values were not different from baseline. Mitral and tricuspid A-wave velocities were not different from baseline at pMM1, but both were significantly higher by pMM8. Conclusions Repetitive obstructive apnoeas produce dynamic, inverse changes in atrial size and Doppler flow across the atrioventricular valves. These observations have important implications for understanding the pathophysiology of OSA. PMID:27127636

  17. 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. PMID:26198448

  18. Passive appendages aid locomotion through symmetry breaking

    NASA Astrophysics Data System (ADS)

    Bagheri, Shervin; Lacis, Ugis; Mazzino, Andrea; Kellay, Hamid; Brosse, Nicolas; Lundell, Fredrik; Ingremeau, Francois

    2014-11-01

    Plants and animals use plumes, barbs, tails, feathers, hairs, fins, and other types of appendages to aid locomotion. Despite their enormous variation, passive appendages may contribute to locomotion by exploiting the same physical mechanism. We present a new mechanism that applies to body appendages surrounded by a separated flow, which often develops behind moving bodies larger than a few millimeters. We use theory, experiments, and numerical simulations to show that bodies with protrusions turn and drift 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 flowing fluid is unstable and how it stabilizes either to the left or right of the incoming fluid flow direction. The discovery suggests a new mechanism of locomotion that may be relevant for certain organisms; for example, how plumed seeds may drift without wind and how motile animals may passively reorient themselves.

  19. Primary Epiploic Appendagitis.

    PubMed

    Matos, Hugo; Costa, Isidoro

    2015-12-01

    Primary epiploic appendagitis is an inflammation of the epiploic appendages occurring due to ischemic infarction as a result of appendage torsion or spontaneous thrombosis usually affecting patients from second to fifth decades, being more common in women and obese patients. It is a self-limiting entity with clinical features similar to other inflammatory abdominal processes and sometimes not remembered at clinical examinations. The awareness of this entity and its correct identification on imaging examinations could prevent unnecessary surgery. The authors present a clinical case complemented with ultrasound and CT images of this entity. PMID:27011574

  20. Passive appendages generate drift through symmetry breaking

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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.

  1. Passive appendages generate drift through symmetry breaking.

    PubMed

    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

  2. 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

  3. Robotic-assisted left atrial ligation for stroke reduction in chronic atrial fibrillation: a case report.

    PubMed

    Kiaii, Bob; McClure, R Scott; Skanes, Alan C; Ross, Ian G; Spouge, Alison R; Swinamer, Stuart; Rayman, Reiza; Bainbridge, Daniel T; Iglesias, Ivan; Novick, Richard J

    2006-01-01

    Patients with atrial fibrillation are at significant risk for sustaining a thromboembolic stroke. More than 90% of thromboemboli form in the left atrial appendage. Ligation of the left atrial appendage to reduce the risk of stroke is often performed in connection with other cardiac surgical procedures. As a stand-alone procedure, however, left atrial ligation has generally been deemed too invasive and has gained little support as an alternative therapeutic option. We report a case of port-access robotic-assisted left atrial ligation as a stand-alone procedure in a patient with chronic atrial fibrillation in whom anticoagulation was a contraindication. To our knowledge, this is the first reported case of stand-alone robotic-assisted left atrial ligation in the literature. PMID:16387671

  4. 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.

  5. Mean corpuscular volume and red cell distribution width as predictors of left atrial stasis in patients with non-valvular atrial fibrillation

    PubMed Central

    Providência, Rui; Ferreira, Maria João; Gonçalves, Lino; Faustino, Ana; Paiva, Luís; Fernandes, Andreia; Barra, Sérgio; Pimenta, Joana; Leitão-Marques, António M

    2013-01-01

    Background: The role of erythrocyte indexes for the prediction of left atrial stasis, assessed by transesophageal echocardiography in patients with non-valvular atrial fibrillation, has not been previously clarified. Methods: Single center cross-sectional study comprising 247 consecutive patients admitted to the emergency department due to symptomatic atrial fibrillation and undergoing transesophageal echocardiogram evaluation for exclusion of left atrial appendage thrombus (LAAT) before cardioversion. All patients had a complete blood count performed up to 12 hours prior to the transesophageal echocardiogram. Markers of left atrial stasis were sought: LAAT, dense spontaneous echocardiographic contrast (DSEC) and low flow velocities (LFV) in the left atrial appendage. Erythrocyte indexes’ accuracy for detecting transesophageal echocardiogram changes was evaluated through receiver operating curve analysis. Binary logistic multivariate analysis, using solely erythrocyte indexes and in combination with other variables (i.e. CHADS2, CHA2DS2VASc classifications and left ventricle ejection fraction), was used for transesophageal echocardiogram endpoints prediction. Results: LAAT was found in 8.5%, DSEC in 26.1% and LFV in 12.1%. Mean corpuscular volume and red cell distribution width were independent predictors of LAAT and DSEC. Despite adding incremental predictive value to each other, when clinical risk factors from CHADS2 and CHA2DS2VASc classifications and left ventricle ejection fraction were added to the models, only mean corpuscular volume remained an independent predictor of LAAT and DSEC. Conclusions: These findings suggest that mean corpuscular volume and red cell distribution width may be linked to left atrial stasis markers. PMID:23785587

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

    PubMed

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

    2016-02-29

    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 120bpm 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

  7. 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

  8. Early Detection of Left Atrial Energy Loss and Mechanics Abnormalities in Diabetic Patients with Normal Left Atrial Size: A Study Combining Vector Flow Mapping and Tissue Tracking Echocardiography

    PubMed Central

    Wang, Yi; Hou, Dailun; Ma, Rongchuan; Ding, Geqi; Yin, Lixue; Zhang, Mei

    2016-01-01

    Background Whether left atrial (LA) functional abnormalities already exist when the LA is of normal size is unknown. The aim of this study was to explore LA energy loss and mechanics changes using vector flow mapping (VFM) and two-dimensional tissue tracking (2DTT) echocardiography in patients with diabetes and normal LA size. Material/Methods This study included 47 normotensive patients with diabetes and 45 controls. The following indexes were measured: LA energy loss during systole (LAELs), early diastole (LAELed), and atrial contraction (LAELac); atrial longitudinal strain during systole (SLAs), early diastole (SLAed) and late diastole (SLAac); and peak LA strain rate during systole (SRLAs), early diastole (SRLAed), and atrial contraction (SRLAac). Results The LAELs and LAELed decreased in diabetic patients compared with controls (P=0.002, P<0.01, respectively), whereas the LAELac increased in diabetic patients (P<0.001). The SLAs, SLAed, SRLAs, and SRLAed (all P<0.01) were all lower in diabetic patients than in controls. However, there was no difference in the SLAac and SRLAac between the two groups. Multivariate regression analysis showed that the LAELs, LAELac, and SRLAs were independently associated with HbA1c in the whole study population. Conclusions LA energy loss and deformation mechanics are already impaired in diabetic patients with normal LA size and the long-term parameter of glycemic control was correlated with them. VFM combined with 2DTT might be a promising tool for the early detection of LA dysfunction caused by impaired glucose metabolism. PMID:27005947

  9. 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. PMID:19460078

  10. Numerical analysis of hemodynamic changes in the left atrium due to atrial fibrillation.

    PubMed

    Koizumi, Ryo; Funamoto, Kenichi; Hayase, Toshiyuki; Kanke, Yusuke; Shibata, Muneichi; Shiraishi, Yasuyuki; Yambe, Tomoyuki

    2015-02-01

    Atrial fibrillation (AF) disrupts movement of the left atrium (LA) and worsens the vital prognosis by causing thromboembolism. Ultrasound Doppler measurement, phase-contrast magnetic resonance imaging (PC MRI), as well as computational fluid dynamics (CFD) have revealed hemodynamic changes in the LA due to AF, such as stagnation of blood flow in the left atrial appendage (LAA). However, quantitative evaluation of the hemodynamics during AF has not been conducted, and the effects of important AF characteristics, such as a lack of active contraction of the LA (atrial kick) in late diastole and the occurrence of high-frequency fibrillation (>400bpm) of the atrial wall, on blood flow field and concomitant hemodynamic stresses have not been completely understood. In this study, the effects of the above-mentioned two characteristic phenomena of AF on blood flow and hemodynamic parameters were quantitatively investigated. Based on MRI of a healthy volunteer heart, one healthy LA model and two AF models (one without atrial kick, and one without atrial kick and with high-frequency fibrillation) were constructed to perform hemodynamic analysis, and the computational results were compared. The results revealed that each characteristic phenomenon of AF influenced hemodynamics. Especially, atrial wall movement by high-frequency fibrillation had a large impact on the stagnation of blood flow. The relative residence time (RRT), which is an indicator of stagnation of blood flow, increased in the upper part of the LAA during AF. This result implies that there is a local thrombus-prone site in LAA when AF occurs. PMID:25547024

  11. The totally thoracoscopic left atrial maze procedure for the treatment of atrial fibrillation.

    PubMed

    van Laar, Charlotte; Geuzebroek, Guillaume S C; Hofman, Frederik N; Van Putte, Bart P

    2016-01-01

    The totally thoracoscopic left atrial maze (TT-maze) is a recent, minimally invasive surgical procedure for the treatment of atrial fibrillation, with promising results in terms of freedom from atrial fibrillation. The TT-maze consists of a bilateral, epicardial pulmonary vein isolation with the creation of a box using radiofrequency and exclusion of the left atrial appendage (LAA). In addition, the box is connected with the base of the LAA and furthermore with the mitral annulus with the so-called trigonum line. In this report, we describe our surgical approach and short-term results. PMID:26993056

  12. Giant atrial septal aneurysm originating from the right coronary artery.

    PubMed

    Osada, Hiroaki; Kanemitsu, Naoki; Meshii, Katsuaki; Ohnaka, Motoaki

    2016-08-01

    Giant coronary artery aneurysm is a rare clinical entity and its involvement in the interatrial space is extremely rare. We here report the rare surgical case of a 67-year old man with giant right coronary artery aneurysm located in the atrial septum with fistula formation to the right atrium, complicated with congestive heart failure, rapid atrial fibrillation and left atrial appendage thrombus. The patient eventually recovered fully without sequelae. PMID:27118290

  13. Atrial natriuretic peptide increases microvascular blood flow and macromolecular escape during renin infusion in the hamster

    SciTech Connect

    Boric, M.P.; Albertini, R. )

    1990-02-01

    The effects of Atrial Natriuretic Peptide (ANP) on microvascular hemodynamics and macromolecular permselectivity were studied in the hamster cheek pouch under resting conditions and during intravenous renin infusion. Fluorescent intravital microscopy was used to observe arteriolar diameters and to detect escape of fluorescent dextran of 150 K-Daltons (FITC-Dx-150). Microvascular plasma flow was estimated by clearance of 51Cr-EDTA and net macromolecular transport by clearance of FITC-Dx-150. At rest, topical ANP (2-250 ng/ml) had no effect on arteriolar diameter, 51Cr-EDTA clearance, relative vascular conductance (RVC) or FITC-Dx-150 clearance. Infusion of renin (10 mU/Kg/Hr, iv) elevated systemic arterial pressure by 30% and reduced cheek pouch RVC by 26%. During renin infusion, topical ANP (50 ng/ml) produced transient arteriolar vasodilation, and increased 51Cr-EDTA clearance (+35%), RVC (+58%) and FITC-Dx-150 clearance (+54%), without affecting systemic pressure. ANP did not induce venular leakage sites under any condition, but changes in FITC-Dx-150 clearance were highly correlated with changes in 51Cr-EDTA clearance, suggesting that the larger macromolecular escape was due to increases in microvascular blood flow and capillary/post-capillary hydrostatic pressure.

  14. Radiology of epiploic appendages: acute appendagitis, post-infarcted appendages, and imaging natural history.

    PubMed

    Eberhardt, S C; Strickland, C D; Epstein, K N

    2016-08-01

    Our aim was to demonstrate the imaging characteristics of epiploic appendages in native, acute inflamed/ischemic and post-infarcted states through retrospective imaging analysis, with clinical and pathologic correlation, and to discuss clinical implications. Cases were gathered mostly retrospectively and reviewed for inclusion based on established diagnostic criteria. Radiology report text search was used to find cases, using terms "epiploic," "appendage," "appendagitis," and "peritoneal body." Data records included patient demographics, relevant clinical data, lesion size, location and apparent imaging composition, and the presence of change or stability in features over multiple studies. Pathologic and clinical data were sought and assessed for correlation. Imaging studies of 198 individuals were included (mean age 50, range 9-95), with a total of 228 lesions: 63 acute and 165 non-acute presentations. All included subjects had CT imaging and some had lesions visible on radiographs, MRI, PET/CT, and sonography. 23 subjects had more than one studied lesion. In addition to classic acute appendagitis, more frequently encountered are post-infarcted appendages either in situ along the colon, adhered to peritoneal or serosal surfaces, or freely mobile in the peritoneum as loose bodies. The majority of the non-acute varieties are recognizable due to peripheral calcification that develops over time following ischemic insult. Multiple cases demonstrated the imaging natural history and confirmed pathologic basis for imaging findings. In summary, acute and post-infarcted epiploic appendages have characteristic imaging appearances and natural history which should provide correct diagnosis in most cases. Incidental post-infarcted epiploica are more commonly encountered than acute presentations. PMID:27142382

  15. The Utility of 3D Left Atrial Volume and Mitral Flow Velocities as Guides for Acute Volume Resuscitation

    PubMed Central

    Santosa, Claudia M.; Rose, David D.; Fleming, Neal W.

    2015-01-01

    Left ventricular end-diastolic pressure (LVEDP) is the foundation of cardiac function assessment. Because of difficulties and risks associated with its direct measurement, correlates of LVEDP derived by pulmonary artery (PA) catheterization or transesophageal echocardiography (TEE) are commonly adopted. TEE has the advantage of being less invasive; however TEE-based estimation of LVEDP using correlates such as left ventricular end-diastolic volume (LVEDV) has technical difficulties that limit its clinical usefulness. Using intraoperative acute normovolemic hemodilution (ANH) as a controlled hemorrhagic model, we examined various mitral flow parameters and three-dimensional reconstructions of left atrial volume as surrogates of LVEDP. Our results demonstrate that peak E wave velocity and left atrial end-diastolic volume (LAEDV) correlated with known changes in intravascular volume associated with ANH. Although left atrial volumetric analysis was done offline in our study, recent advances in echocardiographic software may allow for continuous display and real-time calculation of LAEDV. Along with the ease and reproducibility of acquiring Doppler images of flow across the mitral valve, these two correlates of LVEDP may justify a more widespread use of TEE to optimize intraoperative fluid management. The clinical applicability of peak E wave velocity and LAEDV still needs to be validated during uncontrolled resuscitation. PMID:26236733

  16. 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

  17. 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.

  18. Minimally Invasive Surgical Therapies for Atrial Fibrillation

    PubMed Central

    Nakamura, Yoshitsugu; Kiaii, Bob; Chu, Michael W. A.

    2012-01-01

    Atrial fibrillation is the most common sustained arrhythmia and is associated with significant risks of thromboembolism, stroke, congestive heart failure, and death. There have been major advances in the management of atrial fibrillation including pharmacologic therapies, antithrombotic therapies, and ablation techniques. Surgery for atrial fibrillation, including both concomitant and stand-alone interventions, is an effective therapy to restore sinus rhythm. Minimally invasive surgical ablation is an emerging field that aims for the superior results of the traditional Cox-Maze procedure through a less invasive operation with lower morbidity, quicker recovery, and improved patient satisfaction. These novel techniques utilize endoscopic or minithoracotomy approaches with various energy sources to achieve electrical isolation of the pulmonary veins in addition to other ablation lines. We review advancements in minimally invasive techniques for atrial fibrillation surgery, including management of the left atrial appendage. PMID:22666609

  19. 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.

  20. Molecular histology in skin appendage morphogenesis.

    PubMed

    Widelitz, R B; Jiang, T X; Noveen, A; Ting-Berreth, S A; Yin, E; Jung, H S; Chuong, C M

    1997-08-15

    Classical histological studies have demonstrated the cellular organization of skin appendages and helped us appreciate the intricate structures and function of skin appendages. At this juncture, questions can be directed to determine how these cellular organizations are achieved. How do cells rearrange themselves to form the complex cyto-architecture of skin appendages? What are the molecular bases of the morphogenesis and histogenesis of skin appendages? Recently, many new molecules expressed in a spatial and temporal specific manner during the formation of skin appendages were identified by molecular biological approaches. In this review, novel molecular techniques that are useful in skin appendage research are discussed. The distribution of exemplary molecules from different categories including growth factors, intracellular signaling molecules, homeobox genes, adhesion molecules, and extracellular matrix molecules are summarized in a diagram using feather and hair as models. We hope that these results will serve as the ground work for completing the molecular mapping of skin appendages which will refine and re-define our understanding of the developmental process beyond relying on morphological criteria. We also hope that the listed protocols will help those who are interested in this venture. This new molecular histology of skin appendages is the foundation for forming new hypotheses on how molecules are mechanistically involved in skin appendage development and for designing experiments to test them. This may also lead to the modulation of healing and regeneration processes in future treatment modalities. PMID:9297695

  1. Multimorbidity in Older Adults with Atrial Fibrillation.

    PubMed

    Chen, Michael A

    2016-05-01

    Older adults with atrial fibrillation often have multiple comorbid conditions, including common geriatric syndromes. Pharmacologic therapy, whether for rate control or rhythm control, can result in complications related to polypharmacy in patients who are often on multiple medications for other conditions. Because of uncertainty about the relative risks and benefits of rate versus rhythm control (including antiarrhythmic or ablation therapy), anticoagulation, and procedural treatments (eg, ablation, left atrial appendage closure, pacemaker placement) in older patients with multimorbidity, shared decision-making is essential. However, this may be challenging in patients with cognitive dysfunction, high fall risk, or advanced comorbidity. PMID:27113149

  2. Update on atrial fibrillation: part I.

    PubMed

    Savelieva, Irina; Camm, John

    2008-02-01

    Atrial fibrillation (AF) is an epidemic, affecting 1% to 1.5% of the population in the developed world. Projected data from the population-based studies suggest that the prevalence of AF will grow at least 3-fold by 2050. The health and economic burden imposed by AF and AF-related morbidity is enormous. Atrial fibrillation has a multiplicity of causes ranging from genetic to degenerative, but hypertension and heart failure are the commonest and epidemiologically most prevalent conditions associated with AF as both have been shown to create an arrhythmogenic substrate. Several theories emerged regarding the mechanism of AF, which can be combined into two groups: the single focus hypothesis and the multiple sources hypothesis. Several lines of evidence point to the relevance of both hypotheses to the mechanism of AF, probably with a different degree of involvement depending on the variety of AF (paroxysmal or persistent). Sustained AF alters electrophysiological and structural properties of the atrial myocardium such that the atria become more susceptible to the initiation and maintenance of the arrhythmia, a process known as atrial remodeling. Angiotensin II has been recognized as a key element in atrial remodeling in association with AF opening the possibility of exploitation of "upstream" therapies to prevent or delay atrial remodeling. The clinical significance of AF lies predominantly in a 5-fold increased risk of stroke. The limitations of warfarin prompted the development of new antithrombotic drugs, which include anticoagulants, such as direct oral thrombin inhibitors (dabigatran) and factor Xa inhibitors (rivaroxaban, apixaban). Novel mechanical approaches for the prevention of cardioembolic stroke have recently been evaluated: percutaneous left atrial appendage occluders, minimally invasive surgical isolation of the left atrial appendage, and implantation of carotid filtering devices. PMID:18257025

  3. Surgical Treatment of Atrial Myxomas

    PubMed Central

    Cho, Bum Koo; Lee, Doo Yun; Pezzella, A. Thomas; Hong, Sung Nok; Hong, Pill Whoon

    1989-01-01

    Twenty atrial myxomas were resected in 20 patients with the use of cardiopulmonary bypass, from the beginning of July 1966 through the end of June 1985, at Severance Hospital, Seoul, Korea. Nineteen patients had left atrial myxomas; 1 had a right atrial myxoma. Left atrial myxomas arose from the intra-atrial septum in 17 patients and from the left atrial appendage in 2 patients. The right atrial myxoma arose from the fossa ovalis. The 13 female and 7 male patients ranged in age from 14 to 63 years. Symptoms most often reported on presentation were those associated with mitral valve obstruction; other symptoms were associated with systemic embolization. The 1st 4 patients were tested with angiocardiography alone, and 3 of these were misdiagnosed. The last 16 were tested by angiocardiography, M-mode echocardiography, and 2-dimensional echocardiography, alone or in various combinations, and there were no further misdiagnoses. In our experience, 2-dimensional echocardiography was the most accurate method of diagnosing cardiac tumors. In 19 patients, surgical approach was through a median sternotomy; in the 20th patient, approach was through a left thoracotomy, due to a preoperative misdiagnosis of mitral stenosis. No intraoperative embolizations or deaths occurred. On follow-up of 17 patients during periods ranging from 6 months to 6 years, we had no late deaths, and only 2 patients suffered late complications: 1 had sudden right hemiparesis caused by an embolus 4 months after surgery (this improved upon conservative treatment); and 1 had a recurrence of tumor 3 years after surgery (the new myxoma was successfully resected). We conclude that patients who have undergone complete excision of benign myxomas now have an excellent prognosis, with minimal risk of intraoperative embolization and late recurrence. We conclude also that 2-dimensional echocardiography is an extremely accurate tool both in early diagnosis of intracardiac myxomas and in late follow-up after

  4. The effects of hypoxemia on myocardial blood flow during exercise.

    PubMed

    Paridon, S M; Bricker, J T; Dreyer, W J; Reardon, M; Smith, E O; Porter, C B; Michael, L; Fisher, D J

    1989-03-01

    We evaluated the adequacy of regional and transmural blood flow during exercise and rapid pacing after 1 wk of hypoxemia. Seven mature mongrel dogs were made hypoxemic (mean O2 saturation = 72.4%) by anastomosis of left pulmonary artery to left atrial appendage. Catheters were placed in the left atrium, right atrium, pulmonary artery, and aorta. Atrial and ventricular pacing wires were placed. An aortic flow probe was placed to measure cardiac output. Ten nonshunted dogs, similarly instrumented, served as controls. Recovery time was approximately 1 wk. Cardiac output, mean aortic pressure, and oxygen saturation were measured at rest, with ventricular pacing, atrial pacing, and with treadmill exercise. Ventricular and atrial pace and exercise were at a heart rate of 200. Right ventricular free wall, left ventricular free wall, and septal blood flow were measured with radionuclide-labeled microspheres. Cardiac output, left atrial blood pressure, and aortic blood pressure were similar between the two groups of dogs in all testing states. Myocardial blood flow was significantly higher in the right and left ventricular free wall in the hypoxemic animals during resting and exercise testing states. Myocardial oxygen delivery was similar between the two groups of animals. Pacing resulted in an increase in myocardial blood flow in the control animals but not the hypoxemic animals.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2704596

  5. [A rare case of caudal appendage].

    PubMed

    Andres, S; Boisramé, T; Fritz, G; Viville, B; Kehrli, P; Langer, B; Favre, R

    2015-09-01

    Caudal appendage is a rare malformation which has since ever been interesting. We present the case of a girl in which a caudal appendage was discovered before birth. A throughout checking found an extension from this abnormality to the cordal spine. The baby is operated when 2months old. Differential diagnosis are spina bifida, teratoma and pilonidal sinus. Caudal appendage is one of the typical cutaneous finding with underlying spinal dysraphism, such as hair tuft or pigmented macule. The risk is a tethered cord syndrome that can lead to severe complication. The treatment is either surgery or expectation. PMID:25529458

  6. Appendagitis following Diagnostic Laparoscopy and Laparoscopic Appendicectomy

    PubMed Central

    Kumar, R.; Bamford, R. F.; Kumar, D.

    2016-01-01

    Appendagitis is an uncommon clinical entity, often not recognised, and mistaken for more serious infective conditions. We describe a proven case of appendagitis which occurred after confirmed appendicitis. We postulate that this condition can coexist with appendicitis and indeed may be the result of coinflammation. This has several implications. Firstly, clinicians must retain an index of suspicion for this condition in a patient with localised abdominal pain which occurs after appendicitis. Secondly, it would be reasonable to suggest careful examination of colocated appendages in a patient with an otherwise normal-appearing appendix. Treatment might require laparoscopic resection, as performed in this case. PMID:27462475

  7. Appendagitis following Diagnostic Laparoscopy and Laparoscopic Appendicectomy.

    PubMed

    Kumar, R; Bamford, R F; Kumar, D; Singh-Ranger, G

    2016-01-01

    Appendagitis is an uncommon clinical entity, often not recognised, and mistaken for more serious infective conditions. We describe a proven case of appendagitis which occurred after confirmed appendicitis. We postulate that this condition can coexist with appendicitis and indeed may be the result of coinflammation. This has several implications. Firstly, clinicians must retain an index of suspicion for this condition in a patient with localised abdominal pain which occurs after appendicitis. Secondly, it would be reasonable to suggest careful examination of colocated appendages in a patient with an otherwise normal-appearing appendix. Treatment might require laparoscopic resection, as performed in this case. PMID:27462475

  8. Surgical Ablation of Atrial Fibrillation

    PubMed Central

    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

  9. Acute epiploic appendagitis and its mimics.

    PubMed

    Singh, Ajay K; Gervais, Debra A; Hahn, Peter F; Sagar, Pallavi; Mueller, Peter R; Novelline, Robert A

    2005-01-01

    Acute epiploic appendagitis most commonly manifests with acute lower quadrant pain. Its clinical features are similar to those of acute diverticulitis or, less commonly, acute appendicitis. The conditions that may mimic acute epiploic appendagitis at computed tomography (CT) include acute omental infarction, mesenteric panniculitis, fat-containing tumor, and primary and secondary acute inflammatory processes in the large bowel (eg, diverticulitis and appendicitis). Whereas the location of acute epiploic appendagitis is most commonly adjacent to the sigmoid colon, acute omental infarction is typically located in the right lower quadrant and often is mistaken for acute appendicitis. It is important to correctly diagnose acute epiploic appendagitis and acute omental infarction on CT images because these conditions may be mistaken for acute abdomen, and the mistake may lead to unnecessary surgery. The CT features of acute epiploic appendagitis include an oval lesion 1.5-3.5 cm in diameter, with attenuation similar to that of fat and with surrounding inflammatory changes, that abuts the anterior sigmoid colon wall. The CT features of acute omental infarction include a well-circumscribed triangular or oval heterogeneous fatty mass with a whorled pattern of concentric linear fat stranding between the anterior abdominal wall and the transverse or ascending colon. As CT increasingly is used for the evaluation of acute abdomen, radiologists are likely to see acute epiploic appendagitis and its mimics more often. Recognition of these conditions on CT images will allow appropriate management of acute abdominal pain and may help to prevent unnecessary surgery. PMID:16284132

  10. Relations of Arterial Stiffness and Brachial Flow-Mediated Dilation With New-Onset Atrial Fibrillation: The Framingham Heart Study.

    PubMed

    Shaikh, Amir Y; Wang, Na; Yin, Xiaoyan; Larson, Martin G; Vasan, Ramachandran S; Hamburg, Naomi M; Magnani, Jared W; Ellinor, Patrick T; Lubitz, Steven A; Mitchell, Gary F; Benjamin, Emelia J; McManus, David D

    2016-09-01

    The relations of measures of arterial stiffness, pulsatile hemodynamic load, and endothelial dysfunction to atrial fibrillation (AF) remain poorly understood. To better understand the pathophysiology of AF, we examined associations between noninvasive measures of vascular function and new-onset AF. The study sample included participants aged ≥45 years from the Framingham Heart Study offspring and third-generation cohorts. Using Cox proportional hazards regression models, we examined relations between incident AF and tonometry measures of arterial stiffness (carotid-femoral pulse wave velocity), wave reflection (augmentation index), pressure pulsatility (central pulse pressure), endothelial function (flow-mediated dilation), resting brachial arterial diameter, and hyperemic flow. AF developed in 407/5797 participants in the tonometry sample and 270/3921 participants in the endothelial function sample during follow-up (median 7.1 years, maximum 10 years). Higher augmentation index (hazard ratio, 1.16; 95% confidence interval, 1.02-1.32; P=0.02), baseline brachial artery diameter (hazard ratio, 1.20; 95% confidence interval, 1.01-1.43; P=0.04), and lower flow-mediated dilation (hazard ratio, 0.79; 95% confidence interval, 0.63-0.99; P=0.04) were associated with increased risk of incident AF. Central pulse pressure, when adjusted for age, sex, and hypertension (hazard ratio, 1.14; 95% confidence interval, 1.02-1.28; P=0.02) was associated with incident AF. Higher pulsatile load assessed by central pulse pressure and greater apparent wave reflection measured by augmentation index were associated with increased risk of incident AF. Vascular endothelial dysfunction may precede development of AF. These measures may be additional risk factors or markers of subclinical cardiovascular disease associated with increased risk of incident AF. PMID:27456517

  11. Dynamics of a spinning spacecraft during extension of flexible appendages

    NASA Astrophysics Data System (ADS)

    Turner, J.; Keat, J.; Messac, A.

    1984-05-01

    This paper addresses the problem of analyzing the deployment of flexible appendages from a central rigid hub of a spinning spacecraft. The rigorous mathematical modeling of mass flow and changing structural configuration of the spacecraft during deployment, while the vehicle experiences small elastic deflection and small angular rate, is presented. The equations of motion are obtained in terms of integro-partial differential equations. An approximate solution for the equations of motion is obtained by using a Raleigh-Ritz method and numerical results are presented for several deployment strategies. For every instantaneous physical configuration of the spacecraft, that extension rate which will lead to unstable behavior is also determined.

  12. EDA Signaling and Skin Appendage Development

    PubMed Central

    Cui, Chang-Yi; Schlessinger, David

    2010-01-01

    The same morphogenetic signals are often involved in the development of different organs. For developing skin appendages, a model for tissue-specific regulation of signaling is provided by the EDA pathway, which accesses the otherwise ubiquitous NFκB transcription factors. EDA signaling is mediated by ectodysplasin, EDAR and EDARADD, which form a new TNF ligand-receptor-adaptor family that is restricted to skin appendages in vertebrates from fish to human. The critical function of the pathway was demonstrated in the hereditary genetic disorder Anhidrotic Ectodermal Dysplasia (EDA), which is characterized by defective formation of hair follicles, sweat glands and teeth. The pathway does not appear to initiate the development of the appendages, but is regulated by and regulates the course of further morphogenesis. In mice, transgenic and knockout strains have increasingly revealed features of the mechanism, and suggest possible non-invasive interventions to alleviate EDA deficiency, especially in sweat glands and eyes. PMID:17102627

  13. Dynamics of spacecraft with deploying flexible appendages

    NASA Technical Reports Server (NTRS)

    Downer, Janice D.; Park, K. C.

    1992-01-01

    A computational formulation for the dynamic analysis of spacecraft with deploying appendages is presented. The appendage model is based on a geometrically nonlinear beam formulation which accurately accounts for large rotational and large deformation motions. A moving finite element reference grid is incorporated within the nonlinear beam formulation to model the deployment motion. Hamilton's Law is used to formulate the general equations of motion, and a transient integration solution procedure is derived from a space-time finite element discretization of the Hamiltonian variational statement. Computational results of the methodology are presented for a classical gravity gradient stabilized satellite configuration.

  14. Recurrent orthostatic syncope due to left atrial and left ventricular collapse after a continuous-flow left ventricular assist device implantation.

    PubMed

    Chandra, Avinash; Pradhan, Rajesh; Kim, Francis Y; Frisch, Daniel R; Bogar, Linda J; Bonita, Raphael; Cavarocchi, Nicholas C; Greenspon, Arnold J; Hirose, Hitoshi; Pitcher, Harrison T; Rubin, Sharon; Mather, Paul J

    2013-01-01

    Left ventricular assist devices (LVADs) have become an established treatment for patients with advanced heart failure as a bridge to transplantation or for permanent support as an alternative to heart transplantation. Continuous-flow LVADs have been shown to improve outcomes, including survival, and reduce device failure compared with pulsatile devices. Although LVADs have been shown to be a good option for patients with end-stage heart failure, unanticipated complications may occur. We describe dynamic left atrial and left ventricular chamber collapse related to postural changes in a patient with a recent continuous-flow LVAD implantation. PMID:23260713

  15. 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.

  16. Percutaneous balloon mitral valvuloplasty with bilateral carotid protection in 2 cases of left atrial thrombus.

    PubMed

    Bansal, N O; Duggal, Bhanu; Omnath, R

    2010-01-01

    We present 2 cases of mitral stenosis with left atrial thrombus who underwent Balloon Mitral Valvotomy with bilateral carotid protection using SpiderFX, distal protection devices to minimize the risk of neuroembolic stroke. One patient was critical MS in congestive heart failure with a highly mobile left atrial appendage clot (LAA) and the second patient was a young female who declined surgery and had an LAA clot which did not respond to warfarin therapy. PMID:21180315

  17. A modelling study of atrial septostomy for pulmonary arterial hypertension, and its effect on the state of tissue oxygenation and systemic blood flow.

    PubMed

    Diller, Gerhard-Paul; Lammers, Astrid E; Haworth, Sheila G; Dimopoulos, Konstantinos; Derrick, Graham; Bonhoeffer, Philipp; Gatzoulis, Michael A; Francis, Darrel P

    2010-02-01

    Atrial septostomy is performed in patients with severe pulmonary arterial hypertension, and has been shown to improve symptoms, quality of life and survival. Despite recognized clinical benefits, the underlying pathophysiologic mechanisms are poorly understood. We aimed to assess the effects of right-to-left shunting on arterial delivery of oxygen, mixed venous content of oxygen, and systemic cardiac output in patients with pulmonary arterial hypertension and a fixed flow of blood to the lungs. We formulated equations defining the mandatory relationship between physiologic variables and delivery of oxygen in patients with right-to-left shunting. Using calculus and computer modelling, we considered the simultaneous effects of right-to-left shunting on physiologies with different pulmonary flows, total metabolic rates, and capacities for carrying oxygen. Our study indicates that, when the flow of blood to the lungs is fixed, increasing right-to-left shunting improves systemic cardiac output, arterial blood pressure, and arterial delivery of oxygen. In contrast, the mixed venous content of oxygen, which mirrors the average state of tissue oxygenation, remains unchanged. Our model suggests that increasing the volume of right-to-left shunting cannot compensate for right ventricular failure. Atrial septostomy in the setting of pulmonary arterial hypertension, therefore, increases the arterial delivery of oxygen, but the mixed systemic saturation of oxygen, arguably the most important index of tissue oxygenation, stays constant. Our data suggest that the clinically observed beneficial effects of atrial septostomy are the result of improved flow of blood rather than augmented tissue oxygenation, provided that right ventricular function is adequate. PMID:20144254

  18. Atrial Tachycardias Arising from Ablation of Atrial Fibrillation: A Proarrhythmic Bump or an Antiarrhythmic Turn?

    PubMed Central

    Shah, Ashok J.; Jadidi, Amir; Liu, Xingpeng; Miyazaki, Shinsuke; Forclaz, Andrei; Nault, Isabelle; Rivard, Lena; Linton, Nick; Xhaet, Olivier; Derval, Nicolas; Sacher, Frederic; Bordachar, Pierre; Ritter, Philippe; Hocini, Meleze; Jais, Pierre; Haissaguerre, Michel

    2010-01-01

    The occurrence of atrial tachycardias (AT) is a direct function of the volume of atrial tissue ablated in the patients with atrial fibrillation (AF). Thus, the incidence of AT is highest in persistent AF patients undergoing stepwise ablation using the strategic combination of pulmonary vein isolation, electrogram based ablation and left atrial linear ablation. Using deductive mapping strategy, AT can be divided into three clinical categories viz. the macroreentry, the focal and the newly described localized reentry all of which are amenable to catheter ablation with success rate of 95%. Perimitral, roof dependent and cavotricuspid isthmus dependent AT involve large reentrant circuits which can be successfully ablated at the left mitral isthmus, left atrial roof and tricuspid isthmus respectively. Complete bidirectional block across the sites of linear ablation is a necessary endpoint. Focal and localized reentrant AT commonly originate from but are not limited to the septum, posteroinferior left atrium, venous ostia, base of the left atrial appendage and left mitral isthmus and they respond quickly to focal ablation. AT not only represents ablation-induced proarrhythmia but also forms a bridge between AF and sinus rhythm in longstanding AF patients treated successfully with catheter ablation. PMID:20379387

  19. Syndecan-4 shedding is involved in the oxidative stress and inflammatory responses in left atrial tissue with valvular atrial fibrillation

    PubMed Central

    Wu, Han; Zhou, Qing; Xie, Jun; Li, Guan-Nan; Chen, Qin-Hua; Kang, Li-Na; Xu, Biao

    2015-01-01

    Oxidative stress and inflammation play critical roles in the development and maintenance of atrial fibrillation (AF). In addition, syndecan-4 (Synd4) shedding induced by oxidative stress or inflammation plays a role in the migration of inflammatory cells. Therefore, we hypothesized that Synd4 shedding was also involved in the inflammatory response in atrial fibrillation patients with valvular heart disease. To confirm this suppose, left atrial appendages and clinical data were obtained from 65 patients with valvular disease undergoing valve surgery. Ten left atrial appendages obtained from healthy heart donors were used as controls. Analyses including histopathology, western blotting, and enzyme kinetics were performed to assess the oxidative injury, inflammation responses, and Synd4 shedding. The results showed that the inflammatory response and oxidative injury were increased significantly, whereas as levels of the Synd4 ectodomain was decreased significantly in AF patients. Furthermore, Synd4 ectodomain levels were correlated with atrial oxidative and inflammatory markers. The results showed that Synd4 shedding is a molecular pathological alteration in the development and maintenance of inflammation-associated AF. PMID:26261514

  20. Primary epiploic appendagitis and fructose malabsorption.

    PubMed

    Schnedl, W J; Lipp, R W; Wallner-Liebmann, S J; Kalmar, P; Szolar, D H; Mangge, H

    2014-12-01

    Primary epiploic appendagitis (PEA) is a rare cause of abdominal acute or subacute complaints. Diagnosis of PEA is made when computed tomography (CT) reveals a characteristic lesion. We report on contrast-enhanced CT images of a patient with PEA and regression of inflammation and the reduction in size of the inflamed appendage over the time period of 4 months. Patients with PEA usually recover without medication or surgical treatment within a few weeks. However, due to continuing bloating and irregular bowel movements we investigated carbohydrate malabsorption and diagnosed a fructose malabsorption. Bloating and irregular bowel movements in this patient with PEA were correlated to carbohydrate malabsorption and were treated successfully with a diet free of culprit carbohydrates. PMID:24939434

  1. Early inductive events in ectodermal appendage morphogenesis.

    PubMed

    Biggs, Leah C; Mikkola, Marja L

    2014-01-01

    The embryonic surface ectoderm gives rise to the epidermis and ectodermal appendages including hair follicles, teeth, scales, feathers, and mammary, sweat, and salivary glands. Their early development proceeds largely the same through the induction, placode, and bud stages prior to diversification of epithelial morphogenesis which ultimately produces the wide array of mature organs. In this review we summarize the current knowledge on the molecular and cellular processes driving the shared stages of skin appendage development revealed by analysis of mouse mutants. We focus on three mammalian organs: hair follicle, tooth, and mammary gland. We reevaluate the information gained from classic epithelial-mesenchymal tissue recombination experiments in light of current molecular knowledge. We place special emphasis on the signaling pathways that mediate tissue interactions, and attempt to link the signaling outputs to changes in cellular behavior that ultimately shape the developing organ. PMID:24487243

  2. Torsion of epiploic appendage mimic acute appendicitis.

    PubMed

    Pogorelić, Zenon; Stipić, Radoslav; Druzijanić, Nikica; Perko, Zdravko; Grandić, Leo; Vilović, Katarina; Mrklić, Ivana; Jurić, Ivo; Boschi, Vladimir; Bekavac, Josip

    2011-12-01

    Epiploic appendagitis is a rare cause of focal abdominal pain which, depending on its localisation, can mimic a variety of abdominal diseases. We report a case of 36-year-old woman who presented with a classic signs of acute appendicitis. On examination, the obese, afebrile, and had very strong right iliac fossa tenderness and guarding. The white cell count was 12.82 x 10(9)/L, and C reactive protein count was 15.13MG/DL. She underwent emergency laparoscopic procedure after the acute appendicitis diagnosis has been established. Laparoscopic exploration of the abdominal cavity showed vermiform, no inflamed, appendix and necrotic appendix epiploica of the caecum. The treatment consisted of typical laparoscopic appendectomy and laparoscopic resection of the necrotic appendix epiploica. The patient made rapid recovery and was discharged from the hospital on second day after the operation. Histological investigation of the appendix epiploica revealed gangrenous epiploic appendage. PMID:22397276

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

    PubMed

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

    2016-06-01

    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

  4. 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

  5. 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.

  6. Behavior of tethered debris with flexible appendages

    NASA Astrophysics Data System (ADS)

    Aslanov, Vladimir S.; Yudintsev, Vadim V.

    2014-11-01

    Active exploration of the space leads to growth of a near-Earth space pollution. The frequency of the registered collisions of space debris with functional satellites highly increased during last 10 years. As a rule a large space debris can be observed from the Earth and catalogued, then it is possible to avoid collision with the active spacecraft. However every large debris is a potential source of a numerous small debris particles. To reduce debris population in the near Earth space the large debris should be removed from working orbits. The active debris removal technique is considered that intend to use a tethered orbital transfer vehicle, or a space tug attached by a tether to the space debris. This paper focuses on the dynamics of the space debris with flexible appendages. Mathematical model of the system is derived using the Lagrange formalism. Several numerical examples are presented to illustrate the mutual influence of the oscillations of flexible appendages and the oscillations of a tether. It is shown that flexible appendages can have a significant influence on the attitude motion of the space debris and the safety of the transportation process.

  7. Effects of left atrial receptor stimulation on carotid chemoreceptor-induced renal responses in dogs.

    PubMed

    Karim, F; al-Obaidi, M

    1992-10-01

    1. Dogs were anaesthetized with thiopentone sodium and alpha-chloralose and artificially ventilated. The carotid sinus regions were vascularly isolated and perfused with arterial or venous blood to stimulate the chemoreceptors. Left atrial receptors were stimulated by distending four balloons, three in the left pulmonary vein-atrial junctions and one in the left atrial appendage. Mean aortic pressure was held constant by means of a pressure control device. Atenolol and atropine (2.0 and 0.5 mg kg-1, respectively), and gallamine triethiodide (3.0 mg kg-1 h-1) were given I.V. Renal blood flow was measured by an electromagnetic flowmeter, glomerular filtration rate by creatinine clearance, urinary sodium by flame photometry and solute excretion by osmometry. 2. In fifteen tests in eight dogs (in one dog responses of both left and right kidneys were determined), at a constant aortic pressure (AoP) of 92.0 +/- 3.2 mmHg, and carotid sinus pressure (CSP) of 95.0 +/- 2.0 mmHg, stimulation of left atrial receptors with balloon inflation resulted in significant increases in renal blood flow (RBF) by 8.3 +/- 0.9 from 255.0 +/- 14.6 ml min-1 (100 g kidney weight)-1 (n = 9), in glomerular filtration rate (GFR) by 4.1 +/- 0.6 from 21.2 +/- 1.9 ml min-1 (100 g)-1, in filtration fraction (FF) by 0.04 +/- 0.003 from 0.20 +/- 0.01, in urine flow rate (V) by 0.08 +/- 0.02 from 0.33 +/- 0.05 ml min-1 (100 g)-1, in sodium excretion (UNaV) by 4.4 +/- 0.9 from 27.7 +/- 4.2 mumol min-1 (100 g)-1, in osmolar excretion (UosmV) by 62.0 +/- 5.6 from 303.0 +/- 28.3 mu osmol min-1 (100 g)-1, and in a decrease in free water clearance (CH2O) by 0.13 +/- 0.03 from -0.63 +/- 0.04 ml min-1 (100 g)-1. Left atrial pressure (LAP) and heart rate (HR) did not change significantly from 6.9 +/- 0.3 cmH2O, and 133.0 +/- 3.4 beats min-1 respectively.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:1293287

  8. Can the vicious cycle of obscure or intractable gastrointestinal bleeding be broken in patients with atrial fibrillation subject to anticoagulant therapy?

    PubMed

    Fernández-Rodríguez, Diego; Martín-Yuste, Victoria; Feu, Faust; Brugaletta, Salvatore; Freixa, Xavier; Regueiro, Ander; Sabaté, Manel

    2014-05-01

    Gastrointestinal bleeding of obscure origin or with an intractable cause is particularly common in patients with atrial fibrillation subject to oral anticoagulant therapy. This condition is highly recurrent and therefore gives rise to high morbidity and mortality rates, thus entailing a vicious cycle that is difficult to solve.Percutaneous left atrial appendage closure has become a therapeutic alternative for patients with atrial fibrillation and a contraindication for oral anticoagulation. This technique would allow the discontinuation of oral anticoagulants, thus helping to reduce the risk for gastrointestinal bleeding, and would also be protective against embolic events in this group of patients, thereby eventually breaking this vicious cycle.We report our experience with percutaneous left atrial appendage closure in the management of patients with atrial fibrillation who are subject to oral anticoagulation therapy and suffer from obscure or intractable gastrointestinal bleeding. PMID:25287239

  9. Estimation of the minimum pump speed to prevent regurgitation in the continuous flow left ventricular assist device: left ventricular drainage versus left atrial drainage.

    PubMed

    Tayama, E; Ohashi, Y; Niimi, Y; Takami, Y; Ohtsuka, G; Benkowski, R; Glueck, J A; Nosé, Y

    1997-12-01

    Due to the fact that centrifugal and axial pumps do not require valves, there is a possibility of back flow when the pump speed is low. To estimate the minimum required pump speed to prevent this regurgitation, an in vitro simulation test was conducted. A pulsatile pump simulated the natural heart while a centrifugal pump simulated the continuous flow left ventricular assist device (LVAD). The LVAD flow was attained from the left atrial (LA) drainage or left ventricular (LV) drainage. The minimum or regurgitate flow was observed in the systolic phase with LA drainage and in the diastolic phase with LV drainage. LV drainage always provided higher flow than LA drainage at the same pump speed. These differences are due to the various total pressure heads of the LVAD. To prevent the regurgitation, the LVAD should maintain a certain pump speed which can create positive flow against the aortic systolic pressure with LA drainage and against the aortic diastolic pressure with LV drainage. These required pump speeds can be identified by the LVAD flow-pressure curve. PMID:9423981

  10. Atrial Fibrillation and Stroke

    MedlinePlus

    ... Find People About NINDS NINDS Atrial Fibrillation and Stroke Information Page Table of Contents (click to jump ... done? Clinical Trials What is Atrial Fibrillation and Stroke? Atrial fibrillation (AF) describes the rapid, irregular beating ...

  11. Living with Atrial Fibrillation

    MedlinePlus

    ... Topics » Atrial Fibrillation » Living With Atrial Fibrillation Explore Atrial Fibrillation What Is... Types Other Names Causes Who Is at Risk Signs & Symptoms Diagnosis Treatments Prevention Living With Clinical Trials Links Related Topics Arrhythmia ...

  12. 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.

  13. Atrial fibrillation or flutter

    MedlinePlus

    ... causes of atrial fibrillation include: Alcohol use (especially binge drinking) Coronary artery disease Heart attack or heart ... conditions that cause atrial fibrillation and flutter. Avoid binge drinking.

  14. Atrial Fibrillation Pacing Decreases Intravascular Shear Stress in a New Zealand White Rabbit Model: Implications in Endothelial Function

    PubMed Central

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

    2012-01-01

    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 (NZW) rabbits (n=4) at rapid and irregular intervals. Surface electrical cardiograms (ECG) were recorded for atrial and ventricular rhythm, and intravascular convective heat transfer was measured by micro thermal 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 (∂τ/∂t from 1275 ± 80 to 1056 ± 180 dyne/cm2·s), and reduced ISS (from baseline at 32.0 ± 2.4 to 22.7 ± 3.5 dyne/cm2). Computational fluid dynamics (CFD) code demonstrated that experimentally inferred ISS provided a close approximation to the computed wall shear stress (WSS) 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 τavg=23 ±4 dyn·cm−2·s−1, we further demonstrated that rapid pulse rates at 150 bpm down-regulated endothelial nitric oxide (NO), promoted superoxide (O2·−) production, and increased monocyte binding to endothelial cells. These findings suggest that rapid pacing reduces ISS and ∂τ/∂t, and rapid pulse rates modulate endothelial responses. PMID:22983703

  15. 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

  16. Hedgehog Signaling during Appendage Development and Regeneration.

    PubMed

    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

  17. 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.

  18. 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

  19. Atrial electromechanical sequence in normal subjects and patients with DDD pacemakers.

    PubMed Central

    Wang, K.; Xiao, H. B.; Fujimoto, S.; Gibson, D. G.

    1995-01-01

    OBJECTIVE--To assess the effect of right atrial appendage pacing on atrial electromechanical interrelations in patients with DDD pacemakers. DESIGN--Prospective study by M mode echocardiogram, Doppler echocardiogram, and apexcardiogram, along with electrocardiogram and phonocardiogram. SETTING--Tertiary cardiac referral centre. PATIENTS--20 patients with DDD pacemakers and 20 age matched normal controls. RESULTS--Age, RR interval, atrial size, left ventricular size, and fractional shortening were similar in the two groups. Atrial electromechanical delay (the time from the onset of P wave or atrial pacing spike on ECG to the onset of atrial contraction on M mode echogram) was 68 (SD 7) ms at the lateral site of right atrium, 82 (9) ms at the central fibrous body, 93 (11) ms at the lateral site of left atrium in normals. In patients with DDD pacing, however, this delay increased to 85 (22) ms, 117 (23) ms, and 138 (25) ms respectively (all P < 0.01). Interatrial mechanical delay (the time from the onset of right atrial motion to the onset of the left) increased from 25 (6) ms in normal controls to 53 (18) ms in patients (P < 0.01). Intra-atrial mechanical dispersion (the time from the earliest to the latest onset of regional atrial motion around the atrioventricular ring) in the right atrium increased from 6 (2) ms in normals to 19 (2) ms in patients (P < 0.01), but it remained unchanged in the left atrium (6 (2) ms in normal controls v 7 (2) ms in patients, P > 0.05). Peak atrial shortening rate was not different between the two groups. Differences of atrial electromechanical activity between the two groups were also reflected on Doppler echocardiogram and apexcardiogram. CONCLUSIONS--Right atrial appendage pacing disturbs the normal coordinate sequence of right atrial mechanical activity and leads to a striking and variable increase in intra-atrial conduction time as well as in interatrial conduction time. Left atrial contraction remains synchronous although the

  20. 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

  1. The nature of the atrial receptors responsible for a reflex decrease in activity in renal nerves in the dog

    PubMed Central

    Linden, R. J.; Mary, D. A. S. G.; Weatherill, D.

    1980-01-01

    1. In dogs anaesthetized with chloralose, distension of small balloons in the pulmonary vein—atrial junctions and left atrial appendage, to stimulate left atrial receptors, caused a reduction in activity in efferent renal nerves. This response was maintained during distension of the balloons for 30 min periods. 2. In a second group of dogs, cooling the cervical vagi in steps reduced the magnitude of the response in renal nerves. In seven dogs, the response in fourteen preparations of renal nerves was slightly reduced with the vagi at 18 °C and markedly reduced or abolished at 12 °C. The effect of cooling the vagi was the same as the previously shown effect of cooling on the increase in activity in myelinated afferent vagal fibres during similar stimulation of atrial receptors. 3. In a third group of dogs, the cervical vagi were cooled to 9 °C. In six dogs, fifty-four preparations of renal nerves showed no significant response to distension of the balloons. 4. In a fourth group of dogs, both vagi were sectioned in the neck. In three dogs, twenty-four preparations of renal nerves then showed no response to distension of the balloons. 5. It is concluded that the reduction in activity in efferent renal nerves during distension of small balloons in the pulmonary vein—atrial junctions and left atrial appendage involves only atrial receptors discharging into myelinated vagal fibres. PMID:7381789

  2. Atrial fibrillation.

    PubMed

    Lip, Gregory Y H; Fauchier, Laurent; Freedman, Saul B; Van Gelder, Isabelle; Natale, Andrea; Gianni, Carola; Nattel, Stanley; Potpara, Tatjana; Rienstra, Michiel; Tse, Hung-Fat; Lane, Deirdre A

    2016-01-01

    Atrial fibrillation (AF) is the most common sustained cardiac rhythm disorder, and increases in prevalence with increasing age and the number of cardiovascular comorbidities. AF is characterized by a rapid and irregular heartbeat that can be asymptomatic or lead to symptoms such as palpitations, dyspnoea and dizziness. The condition can also be associated with serious complications, including an increased risk of stroke. Important recent developments in the clinical epidemiology and management of AF have informed our approach to this arrhythmia. This Primer provides a comprehensive overview of AF, including its epidemiology, mechanisms and pathophysiology, diagnosis, screening, prevention and management. Management strategies, including stroke prevention, rate control and rhythm control, are considered. We also address quality of life issues and provide an outlook on future developments and ongoing clinical trials in managing this common arrhythmia. PMID:27159789

  3. Clinical and histological predictive risk factors of atrial fibrillation in patients undergoing open-heart surgery

    PubMed Central

    TINICA, GRIGORE; MOCANU, VERONICA; ZUGUN-ELOAE, FLORIN; BUTCOVAN, DOINA

    2015-01-01

    Postoperative atrial fibrillation (POAF) is a common complication subsequent to cardiac surgery. Various risk factors have been reported for the development of this complication; however, their precise role in POAF is unknown. In the present study, we attempted to identify clinical factors and histopathological changes in atrial tissue that may predict the development of POAF. Atrial tissue was sampled from 103 patients in sinus rhythm that had undergone open-heart surgery, including elective coronary artery bypass grafting (79.61%) and heart valve surgery (20.38%). Atrial surgical biopsies were obtained from the right atrial appendage at the site of cannulation, prior to cardiopulmonary bypass. Tissues were processed routinely for light microscopy, then stained with hematoxylin and eosin and sirius red. Microscopical exams were used to observe the atrial lesions and morphometry was conducted for quantification. In total, 37 patients (35.92%) developed POAF and atrial lesions were identified in the majority of patients in the normal postoperative sinus rhythm and POAF groups, but were most common in the POAF patients. The most common risk factors involved in developing POAF were found to be: Age of >60 years, male gender, ejection fraction of <50% and increased pulmonary hypertension. Furthermore, interstitial fibrosis and myocytolysis were the most common injuries identified. Abnormalities in atrial surgical biopsies may indicate the susceptibility of a patient to developing POAF. The present results suggest that the pre-existent alterations in the structure of the right atrium may be a major determinant in the development of POAF. PMID:26668632

  4. 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

  5. Functional Role and Mechanism of microRNA-28b in Atrial Myocyte in a Persistent Atrial Fibrillation Rat Model

    PubMed Central

    Wang, Yongbin; Kang, Weiqiang; Wang, Xu; Chen, Meina; Qin, Qiaoji; Guo, Minglei; Ge, Zhiming

    2016-01-01

    Background Persistent atrial fibrillation has been indicated to be related with microRNA-28b. However, the exact role of microRNA-28b in persistent atrial fibrillation needs to be further elucidated. Therefore, this study aimed to establish a rat model of persistent atrial fibrillation to investigate the level of microRNA-28b in atrial myocytes and to explore the molecular mechanism involved. Material/Methods A persistent atrial fibrillation model was established in rats by using chronic rapid atrial pacing induction. The size of the heart was measured by ultrasonic method. The expression of microRNA-28b in left atrial myocytes was quantified by RT-PCR. Cardiomyocytes were isolated and cultured to detect cell proliferation and apoptosis by MTT and flow cytometry, respectively. The specific inhibitor of ERK signaling pathway, PD98059, was used to further illustrate the role of ERK signaling pathway in the modulation of cardiomyocytes in persistent atrial fibrillation. Results MicroRNA-28b was up-regulated in the experimental rat model with persistent atrial fibrillation. The proliferation of cardiomyocytes was significantly inhibited with potentiated apoptosis. Blockage of the ERK pathway suppressed the microRNA-28b expression and inhibited cell apoptosis. Conclusions microRNA-28b-induced growth inhibition and cell apoptosis of atrial myocytes was observed in the rat model with persistent atrial fibrillation, via activation of the ERK signaling pathway. PMID:27574952

  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. Atrial Fibrillation in Children

    MedlinePlus

    ... Pressure High Blood Pressure Tools & Resources Stroke More Atrial Fibrillation in Children Updated:Jul 18,2016 Does your ... content was last reviewed on 04/16/14. Atrial Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters • ...

  8. [Atrial fibrillation].

    PubMed

    Colín Lizalde, L J

    2001-01-01

    Atrial fibrillation (AF) is the most common sustained arrhythmia. AF has now been exhaustively studied: more is known about its mechanism and research is moving towards new forms of treatment. For chronic AF, basically the control of ventricular rate and the brain protection are the main issues. It is well known that with the identification of high risk group for embolism, oral anticoagulation should be administered. Ventricular rate control can be achieved by using betablockers or calcium channel blockers, unless these are contraindicated for the elderly. Oral anticoagulation prevents the stroke. The main mechanism of AF is the re-entry of multiple wavelets, but now it is more frequently found on patients with focal AF. Therapies are employed to bring the patient to a sinusal rhythm as soon as possible with antiarryhthmics or electric cardioversion externally or internally. The internal procedure includes 1 to 15 J and the success rate is of 91% vs 67% in relation to the external one. The introduction of the catheter ablation has opened new frontiers for the treatment of AF, first as the ablate-and-pace technique and now trying to mimic the maze procedure or with the ablation of the focal tachycardia. The stimulation for prevention of AF under research, as well as the implantable dysfibrillation for selected patients. On going studies will show the possible benefit of this type of benefits. PMID:11565343

  9. Catheter Ablation for Long-Standing Persistent Atrial Fibrillation

    PubMed Central

    Romero, Jorge; Gianni, Carola; Di Biase, Luigi; Natale, Andrea

    2015-01-01

    Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide and represents a major burden to health care systems. Atrial fibrillation is associated with a 4- to 5-fold increased risk of thromboembolic stroke. The pulmonary veins have been identified as major sources of atrial triggers for AF. This is particularly true in patients with paroxysmal AF but not always the case for those with long-standing persistent AF (LSPAF), in which other locations for ectopic beats have been well recognized. Structures with foci triggering AF include the coronary sinus, the left atrial appendage (LAA), the superior vena cava, the crista terminalis, and the ligament of Marshall. More than 30 studies reporting results on radiofrequency ablation of LSPAF have been published to date. Most of these are observational studies with very different methodologies using different strategies. As a result, there has been remarkable variation in short- and long-term success, which suggests that the optimal ablation technique for LSPAF is still to be elucidated. In this review we discuss the different approaches to LSPAF catheter ablation, starting with pulmonary vein isolation (PVI) through ablation lines in different left atrial locations, the role of complex fractionated atrial electrograms, focal impulses and rotor modulation, autonomic modulation (ganglionated plexi), alcohol ablation, and the future of epicardial mapping and ablation for this arrhythmia. A stepwise ablation approach requires several key ablation techniques, such as meticulous PVI, linear ablation at the roof and mitral isthmus, electrogram-targeted ablation with particular attention to triggers in the coronary sinus and LAA, and discretionary right atrial ablation (superior vena cava, intercaval, or cavotricuspid isthmus lines). PMID:26306125

  10. 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

  11. Feather-like development of Triassic diapsid skin appendages

    NASA Astrophysics Data System (ADS)

    Voigt, Sebastian; Buchwitz, Michael; Fischer, Jan; Krause, Daniel; Georgi, Robert

    2009-01-01

    Of the recent sauropsid skin appendage types, only feathers develop from a cylindrical epidermal invagination, the follicle, and show hierarchical branching. Fossilized integuments of Mesozoic diapsids have been interpreted as follicular and potential feather homologues, an idea particularly controversially discussed for the elongate dorsal skin projections of the small diapsid Longisquama insignis from the Triassic of Kyrgyzstan. Based on new finds and their comparison with the type material, we show that Longisquama’s appendages consist of a single-branched internal frame enclosed by a flexible outer membrane. Not supporting a categorization either as feathers or as scales, our analysis demonstrates that the Longisquama appendages formed in a two-stage, feather-like developmental process, representing an unusual early example for the evolutionary plasticity of sauropsid integument.

  12. Atrial fibrillation.

    PubMed

    Bang, Casper N

    2013-10-01

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

  13. Atrial Septal Defect (For Teens)

    MedlinePlus

    ... I Help a Friend Who Cuts? Atrial Septal Defect KidsHealth > For Teens > Atrial Septal Defect Print A ... Care of Yourself What Is an Atrial Septal Defect? Having a doctor listen to your heart is ...

  14. 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.

  15. In vivo porcine left atrial wall stress: Computational model.

    PubMed

    Di Martino, Elena S; Bellini, Chiara; Schwartzman, David S

    2011-10-13

    Most computational models of the heart have so far concentrated on the study of the left ventricle, mainly using simplified geometries. The same approach cannot be adopted to model the left atrium, whose irregular shape does not allow morphological simplifications. In addition, the deformation of the left atrium during the cardiac cycle strongly depends on the interaction with its surrounding structures. We present a procedure to generate a comprehensive computational model of the left atrium, including physiological loads (blood pressure), boundary conditions (pericardium, pulmonary veins and mitral valve annulus movement) and mechanical properties based on planar biaxial experiments. The model was able to accurately reproduce the in vivo dynamics of the left atrium during the passive portion of the cardiac cycle. A shift in time between the peak pressure and the maximum displacement of the mitral valve annulus allows the appendage to inflate and bend towards the ventricle before the pulling effect associated with the ventricle contraction takes place. The ventricular systole creates room for further expansion of the appendage, which gets in close contact with the pericardium. The temporal evolution of the volume in the atrial cavity as predicted by the finite element simulation matches the volume changes obtained from CT scans. The stress field computed at each time point shows remarkable spatial heterogeneity. In particular, high stress concentration occurs along the appendage rim and in the region surrounding the pulmonary veins. PMID:21907340

  16. Toward standardized mapping for left atrial analysis and cardiac ablation guidance

    NASA Astrophysics Data System (ADS)

    Rettmann, M. E.; Holmes, D. R.; Linte, C. A.; Packer, D. L.; Robb, R. A.

    2014-03-01

    In catheter-based cardiac ablation, the pulmonary vein ostia are important landmarks for guiding the ablation procedure, and for this reason, have been the focus of many studies quantifying their size, structure, and variability. Analysis of pulmonary vein structure, however, has been limited by the lack of a standardized reference space for population based studies. Standardized maps are important tools for characterizing anatomic variability across subjects with the goal of separating normal inter-subject variability from abnormal variability associated with disease. In this work, we describe a novel technique for computing flat maps of left atrial anatomy in a standardized space. A flat map of left atrial anatomy is created by casting a single ray through the volume and systematically rotating the camera viewpoint to obtain the entire field of view. The technique is validated by assessing preservation of relative surface areas and distances between the original 3D geometry and the flat map geometry. The proposed methodology is demonstrated on 10 subjects which are subsequently combined to form a probabilistic map of anatomic location for each of the pulmonary vein ostia and the boundary of the left atrial appendage. The probabilistic map demonstrates that the location of the inferior ostia have higher variability than the superior ostia and the variability of the left atrial appendage is similar to the superior pulmonary veins. This technique could also have potential application in mapping electrophysiology data, radio-frequency ablation burns, or treatment planning in cardiac ablation therapy.

  17. Minimally invasive surgery for atrial fibrillation.

    PubMed

    Zembala, Michael O; Suwalski, Piotr

    2013-11-01

    Atrial fibrillation (AF) remains the most common cardiac arrhythmia, affecting nearly 2% of the general population worldwide. Minimally invasive surgical ablation remains one of the most dynamically evolving fields of modern cardiac surgery. While there are more than a dozen issues driving this development, two seem to play the most important role: first, there is lack of evidence supporting percutaneous catheter based approach to treat patients with persistent and long-standing persistent AF. Paucity of this data offers surgical community unparalleled opportunity to challenge guidelines and change indications for surgical intervention. Large, multicenter prospective clinical studies are therefore of utmost importance, as well as honest, clear data reporting. Second, a collaborative methodology started a long-awaited debate on a Heart Team approach to AF, similar to the debate on coronary artery disease and transcatheter valves. Appropriate patient selection and tailored treatment options will most certainly result in better outcomes and patient satisfaction, coupled with appropriate use of always-limited institutional resources. The aim of this review, unlike other reviews of minimally invasive surgical ablation, is to present medical professionals with two distinctly different, approaches. The first one is purely surgical, Standalone surgical isolation of the pulmonary veins using bipolar energy source with concomitant amputation of the left atrial appendage-a method of choice in one of the most important clinical trials on AF-The Atrial Fibrillation Catheter Ablation Versus Surgical Ablation Treatment (FAST) Trial. The second one represents the most complex approach to this problem: a multidisciplinary, combined effort of a cardiac surgeon and electrophysiologist. The Convergent Procedure, which includes both endocardial and epicardial unipolar ablation bonds together minimally invasive endoscopic surgery with electroanatomical mapping, to deliver best of the

  18. Intentional Right Atrial Exit and Carbon Dioxide Insufflation to Facilitate Subxiphoid Needle Entry Into the Empty Pericardial Space

    PubMed Central

    Greenbaum, Adam B.; Rogers, Toby; Paone, Gaetano; Flynn, Shawn E.; Guerrero, Mayra E.; O’Neill, William W.; Lederman, Robert J.

    2015-01-01

    OBJECTIVES The purpose of this study was to test whether a microcatheter can safely be advanced across the right atrial appendage to access the pericardium and then withdrawn despite subsequent high-intensity anticoagulation. We also tested whether transatrial pericardial insufflation of carbon dioxide (CO2) would enhance the safety of subxiphoid needle access to the empty pericardium by separating the heart from the anterior pericardium. BACKGROUND Subxiphoid needle access to the empty pericardium, required for left atrial suture ligation and epicardial ablation for rhythm disorders, risks myocardial or coronary laceration. METHODS A catheter from the femoral vein engaged the right atrial appendage for angiographic confirmation of position. Through that catheter, the back end of a 0.014- or 0.018-inch guidewire crossed the right atrial wall to enter the pericardium and delivered a 2.4-F microcatheter. CO2 1 to 2 ml/kg was insufflated into the pericardium immediately before subxiphoid needle access under lateral projection fluoroscopy. Thirteen patients undergoing subxiphoid suture ligation of the left atrial appendage consented to participate in this research protocol. RESULTS Right atrial exit succeeded in 11 subjects (85%) and failed uneventfully in 2 subjects. CO2 insufflation of 96 ± 22 ml achieved 12 ± 4 mm separation of the anterior pericardium from the myocardial wall, allowed rapid and successful subxiphoid anterior needle and guidewire entry in all 11 subjects, and did not have any evident hemodynamic effects. The immediate pericardial aspirate was serous in all but 1 subject. CONCLUSIONS We report the first human intentional transatrial exit procedure. Transatrial microcatheter access to the pericardium can be achieved safely. Pericardial insufflation with CO2 makes subxiphoid access to the empty pericardium rapid and safe. Although our clinical experience to date remains small, with further experience, this approach may prevent the life

  19. Evaluation of some Vulval Appendages in Nematode Taxonomy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A survey of the nature and phylogenetic distribution of nematode vulval appendages revealed three major classes based on composition, position and orientation: membranes, flaps, and epiptygma. Minor classes included cuticular inflations, vulval tubes of extruded gonadal tissues, vulval ridges, and p...

  20. Phenotypic determination of epithelial appendages: genes, developmental pathways, and evolution.

    PubMed

    Chuong, C M; Noveen, A

    1999-12-01

    Epithelial appendages are derivatives of epithelia that elaborate to form specialized structures and functions. The appendage can protrude out, such as in teeth and feathers, or invaginate in, such as in glands. The epithelia can be ectodermal, such as in hairs, or endodermal, such as in livers. Using feather as a prototype of epithelial appendage, we study the molecular signals involved in the successive stages of epithelial-mesenchymal interactions during morphogenesis. We propose that these form the basics of gene networks, which can be integrated to gene supernetwork and totinetwork. Because the unit of development is molecular pathway rather than single molecule, and the unit of morphogenesis is cell group rather than single cell, we make the analogy between genes/developmental pathways and words/sentences. The study of developmental pathways in epithelial appendage organogenesis will help us to understand the grammar of genes and the basic rules in constructing regulated new growth. This knowledge may contribute to the study of cancer biology (deregulated new growth) and organ regeneration. PMID:10674387

  1. 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. PMID:26476248

  2. Atrial natriuretic peptide frameshift mutation in familial atrial fibrillation.

    PubMed

    Hodgson-Zingman, Denice M; Karst, Margaret L; Zingman, Leonid V; Heublein, Denise M; Darbar, Dawood; Herron, Kathleen J; Ballew, Jeffrey D; de Andrade, Mariza; Burnett, John C; Olson, Timothy M

    2008-07-10

    Atrial fibrillation is a common arrhythmia that is hereditary in a small subgroup of patients. In a family with 11 clinically affected members, we mapped an atrial fibrillation locus to chromosome 1p36-p35 and identified a heterozygous frameshift mutation in the gene encoding atrial natriuretic peptide. Circulating chimeric atrial natriuretic peptide (ANP) was detected in high concentration in subjects with the mutation, and shortened atrial action potentials were seen in an isolated heart model, creating a possible substrate for atrial fibrillation. This report implicates perturbation of the atrial natriuretic peptide-cyclic guanosine monophosphate (cGMP) pathway in cardiac electrical instability. PMID:18614783

  3. Innominate vein-right atrial bypass for relief of superior vena cava syndrome due to pacemaker lead thrombosis.

    PubMed

    Deo, Salil V; Burkhart, Harold M; Araoz, Philip A; Brady, Peter A

    2010-11-01

    We present a patient with superior vena cava (SVC) obstruction due to multiple intraluminal pacemaker leads. Previous attempts at balloon dilatation of the SVC and surgical angioplasty did not provide a long-term solution. A Gore-Tex (W. L. Gore & Associates, Flagstaff, AZ, USA) conduit interposed between the innominate vein and right atrial appendage has resulted in symptomatic relief at a follow-up of 6 months. PMID:21039859

  4. Atrial mass: a myxoma?

    PubMed

    Chatzis, Andrew C; Kostopanagiotou, Kostas; Kousi, Theofili; Mitropoulos, Fotios

    2016-08-01

    A middle-aged woman with a history of resected colorectal cancer and receiving chemotherapy presented with a right atrial mass and the provisional diagnosis of myxoma supported by echocardiography, computed tomography, and magnetic resonance imaging. Successful surgical removal revealed organized thrombus instead. Atrial thrombus may be mistaken for myxoma and long-term intracardiac indwelling catheters can be thrombogenic. PMID:27525099

  5. Pathophysiologic basis of autonomic ganglionated plexus ablation in patients with atrial fibrillation.

    PubMed

    Nakagawa, Hiroshi; Scherlag, Benjamin J; Patterson, Eugene; Ikeda, Atsuhsi; Lockwood, Deborah; Jackman, Warren M

    2009-12-01

    The intrinsic cardiac autonomic nervous system (ganglionated plexuses [GP]) plays a significant role in the initiation and maintenance of atrial fibrillation (AF) in both experimental models and AF patients. Left atrial GP, located in epicardial fat pads and the ligament of Marshall, contain afferent neurons from the atrial myocardium and the central autonomic nervous system, efferent neurons (cholinergic and adrenergic neurons), and interconnecting neurons, which allow communication between GP. Stimulation of the GP produces both parasympathetic stimulation (markedly shortens action potential duration) and sympathetic stimulation (increases calcium transient) in the pulmonary vein (PV) myocardium and atrial myocardium. In a canine model, GP stimulation resulted in early afterdepolarizations, and calcium transient triggered firing in the adjacent PV and initiated AF. Fractionated atrial potentials (FAP) were consistently located in the left atrium close to the stimulated GP. Ablation of the stimulated GP eliminated the FAP surrounding the GP. In patients with paroxysmal AF, epicardial and endocardial high-frequency stimulation produced a positive vagal response (transient AV block during AF and hypotension), allowing the identification and localization of five major left atrial GP (superior left GP, inferior left GP, Marshall tract GP, anterior right GP, inferior right GP). High-density electroanatomic maps of the left atrium and PVs obtained during AF showed the FAP are located in four main left atrial areas (left atrial appendage ridge FAP area, superior-left FAP area, inferoposterior FAP area, anterior-right FAP area). All five GP are located within one of the four FAP areas. In 63 patients with paroxysmal AF, GP ablation alone (before PV antrum isolation) significantly decreased the occurrence of PV firing (47/63 patients before ablation vs 9/63 patients after ablation, P <.01). GP ablation also decreased the inducibility of sustained AF (43/63 patients vs 23

  6. 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

  7. Phrenic Nerve Injury After Catheter Ablation of Atrial Fibrillation

    PubMed Central

    Sacher, Frederic; Jais, Pierre; Stephenson, Kent; O'Neill, Mark D; Hocini, Meleze; Clementy, Jacques; Stevenson, William G; Haissaguerre, Michel

    2007-01-01

    Phrenic Nerve Injury (PNI) has been well studied by cardiac surgeons. More recently it has been recognized as a potential complication of catheter ablation with a prevalence of 0.11 to 0.48 % after atrial fibrillation (AF) ablation. This review will focus on PNI after AF ablation Anatomical studies have shown a close relationship between the right phrenic nerve and it's proximity to the superior vena cava (SVC), and the antero-inferior part of the right superior pulmonary vein (RSPV). In addition, the proximity of the left phrenic nerve to the left atrial appendage has been well established. Independent of the type of ablation catheter (4mm, 8 mm, irrigated tip, balloon) or energy source used (radiofrequency (RF), ultrasound, cryothermia, and laser); the risk of PNI exists during ablation at the critical areas listed above. Although up to thirty-one percent of patients with PNI after AF ablation remain asymptomatic, dyspnea remain the cardinal symptom and is present in all symptomatic patients. Despite the theoretical risk for significant adverse effect on functional status and quality of life, short-term outcomes from published studies appear favorable with 81% of patients with PNI having a complete recovery after 7 ± 7 months. Conclusion Existing studies have described PNI as an uncommon but avoidable complication in patients undergoing pulmonary vein isolation for AF. Prior to ablation at the SVC, antero-inferior RSPV ostium or the left atrial appendage, pacing should be performed before energy delivery. If phrenic nerve capture is documented, energy delivery should be avoided at this site. Electrophysiologist's vigilance as well as pacing prior to ablation at high risk sites in close proximity to the phrenic nerve are the currently available tools to avoid the complication of PNI. PMID:17235367

  8. [Cardioversion and atrial stunning].

    PubMed

    Dabek, Józefa; Gasior, Zbigniew; Monastyrska-Cup, Barbara; Jakubowski, Daniel

    2007-03-01

    Stunned atrium is defined as a state of temporary mechanic atrial dysfunction with preserved bioeletrical function. It may follow up to 38-80% successful cardioversions performed to convert atrial fibrillation to regular sinus rhythm. Lack of effective atrial contractility leads to hemodynamic changes, which may result in thrombus formation with subsequent thromboembolic events. It becomes a priority to research in depth the pathophysiology of stunned atrium phenomenon and form strategies to avoid complications associated with it. Studies have shown, that even patients who had no evidence of thrombotic material (as proven by transesophageal echocardiography performed prior to cardioversion), are still at increased risk of embolic events. This fact created basis for hypothesis, that conditions for clot formation may be met only when sinus rhythm is restored. 93% of thrombi are accompanied by so-called spontaneous contrast phenomenon. The purpose of our study was to find relations between factors contributing to stunned atrium and its cellular mechanisms. It is suggested, that stunned atrium results from changes in atrial muscular membrane which occur during atrial fibrillation. Stunned atrium is encountered more frequently in patients with coronary artery disease than in hypertensive heart disease or even lone atrial fibrillation. It is also associated with rheumatic valvular abnormalities and left ventricular dysfunction from other causes. Studies have shown no correlation between the frequency of stunned atrium and the mode of cardioversion. It was observed, that duration of atrial fibrillation and dimensions of atria have substantial impact on time to mechanical function recovery and magnitude of atrial stunning. Studies on subjects undergoing cardioversion due to atrial fibrillation proved that there is a higher tendency to stunned atrium in patients with atrial enlargement. Due to significant delay until full mechanical function recovery, it is of prominent

  9. Bilateral Atrial Myxoma: A Case Report.

    PubMed

    Susupaus, Attapoom; Foofuengmonkolkit, Kumpoo

    2016-02-01

    Among the rare cardiac tumors, myxoma, which is mostly located in the left atrium, is the most common type. Bilateral atrial myxoma is extremely rare, and requires urgent surgery. The authors report the case of a 34-year-old male, who presented with one month of right hemiparesis and aphasia and subsequently diagnosed with bilateral atrial myxoma based on transthoracic echocardiography. An urgent operation for intra-cardiac tumor removal was performed with the biatrial approach. Once a diagnosis of myxoma has been made, an urgent operation for tumor removal is necessary due to the risk of serious complications, including sudden death from normal blood flow obstruction. PMID:27266240

  10. Atrial fibrillation ablation.

    PubMed

    Pappone, Carlo; Santinelli, Vincenzo

    2012-06-01

    Atrial fibrillation is the commonest cardiac arrhythmia, with significant morbidity related to symptoms, heart failure, and thromboembolism, which is associated with excess mortality. Over the past 10 years, many centers worldwide have reported high success rates and few complications after a single ablation procedure in patients with paroxysmal atrial fibrillation. Recent studies indicate a short-term and long-term superiority of catheter ablation as compared with conventional antiarrhythmic drug therapy in terms of arrhythmia recurrence, quality of life, and arrhythmia progression. As a result, catheter ablation is evolving to a front-line therapy in many patients with atrial fibrillation. However, in patients with persistent long-standing atrial fibrillation catheter ablation strategy is more complex and time-consuming, frequently requiring repeat procedures to achieve success rates as high as in paroxysmal atrial fibrillation. In the near future, however, with growing experience and evolving technology, catheter ablation of atrial fibrillation may be extended also to patients with long-standing atrial fibrillation. PMID:22541284

  11. Left atrial booster function in valvular heart disease

    PubMed Central

    Heidenreich, Fred P.; Shaver, James A.; Thompson, Mark E.; Leonard, James J.

    1970-01-01

    This study was designed to assess atrial booster pump action in valvular heart disease and to dissect booster pump from reservoir-conduit functions. In five patients with aortic stenosis and six with mitral stenosis, sequential atrioventricular (A-V) pacing was instituted during the course of diagnostic cardiac catheterization. Continuous recording of valvular gradient allowed estimation of flow for each cardiac cycle by transposition of the Gorlin formula. Left ventricular ejection time and left ventricular stroke work in aortic stenosis or left ventricular mean systolic pressure in mitral stenosis were also determined. Control observations were recorded during sequential A-V pacing with well-timed atrial systole. Cardiac cycles were then produced with no atrial contraction but undisturbed atrial reservoir function by intermittently interrupting the atrial pacing stimulus during sequential A-V pacing. This intervention significantly reduced valvular gradient, flow, left ventricular ejection time, and left ventricular mean systolic pressure or stroke work. Cardiac cycles were then produced with atrial booster action eliminated by instituting synchronous A-V pacing. The resultant simultaneous contraction of the atrium and ventricle not only eliminated effective atrial systole but also placed atrial systole during the normal period of atrial reservoir function. This also significantly reduced all the hemodynamic measurements. However, comparison of the magnitude of change from these two different pacing interventions showed no greater impairment of hemodynamic state when both booster pump action and reservoir function were impaired than when booster pump action alone was impaired. The study confirms the potential benefit of well placed atrial booster pump action in valvular heart disease in man. PMID:5449701

  12. Vibration suppression of a spacecraft flexible appendage using smart material

    NASA Astrophysics Data System (ADS)

    Meyer, John L.; Harrington, William B.; Agrawal, Brij N.; Song, Gangbing

    1998-02-01

    This paper presents the results of positive position feedback (PPF) control and linear-quadratic Gaussian (LQG) control for vibration suppression of a flexible structure using piezoceramics. Experiments were conducted on the US Naval Postgraduate School's flexible spacecraft simulator (FSS), which is comprised of a rigid central body and a flexible appendage. The objective of this research is to suppress the vibration of the flexible appendage. Experiments show that both control methods have unique advantages for vibration suppression. PPF control is effective in providing high damping for a particular mode and is easy to implement. LQG control provides damping to all modes; however, it cannot provide high damping for a specific mode. LQG control is very effective in meeting specific requirements, such as minimization of tip motion of a flexible beam, but at a higher implementation cost.

  13. 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.

  14. Atrial Fibrillation, Congestive Heart Failure, and the Middle Cerebral Artery.

    PubMed

    Ameriso, S F; Sager, P; Fisher, M

    1992-10-01

    Atrial fibrillation and congestive heart failure are risk factors for ischemic stroke usually attributed to cardiac embolism. To define potential alternative mechanisms, patients with atrial fibrillation and congestive heart failure were investigated by transcranial Doppler. Middle cerebral artery (MCA) blood flow velocities were analyzed in neurologically asymptomatic patients with nonvalvular (n = 10) and valvular (n = 13) atrial fibrillation, patients in normal sinus rhythm with congestive heart failure (n = 13), and control subjects (n = 11). Compared to patients in sinus rhythm with congestive heart failure and to control subjects, patients in both atrial fibrillation groups had significantly greater beat-to-beat variation in peak, mean, and diastolic velocities and in pulsatility index. Peak, mean, and diastolic MCA velocities in patients with atrial fibrillation and those with congestive heart failure were significantly less than those in control subjects. Patients with nonvalvular atrial fibrillation had a higher pulsatility index compared to each of the other three groups. These findings demonstrate substantial nonemboligenic alterations of the intracranial circulation associated with atrial fibrillation and congestive heart failure, and also provide an intracranial hemodynamic profile that may distinguish valvular from nonvalvular atrial fibrillation. PMID:27309151

  15. Predictive value of serum uric acid on left atrial spontaneous echo contrast in non-valvular atrial fibrillation patients

    PubMed Central

    Liao, Hong-Tao; Liu, Fang-Zhou; Xue, Yu-Mei; Zhan, Xian-Zhang; Fang, Xian-Hong; Huang, Jun; Wei, Wei; Rao, Fang; Deng, Hai; Liu, Yang; Lin, Wei-Dong; Wu, Shu-Lin

    2015-01-01

    Objectives To investigate the relationship between serum uric acid (SUA) and left atrial spontaneous echo contrast (LA-SEC) in non-valvular atrial fibrillation (AF) patients. Methods We retrospectively screened 1,476 consecutive hospitalized patients with AF who underwent transesophageal echocardiography prior to radiofrequency catheter ablation, left atrial appendage closure and electric cardioversion at Guangdong General Hospital. Data on the clinical baseline characteristics of all patients were collected from electronic medical records and analyzed. Results After exclusion of patients with left atrial thrombus, 1,354 patients entered into present study and 57 were LA-SEC. The mean female SUA level (380.88 ± 94.35 µmol/L vs. 323.37 ± 72.19 µmol/L, P < 0.001) and male SUA level (416.97 ± 98.87 µmol/L vs. 367.88 ± 68.50 µmol/L, P = 0.008) were both significantly higher in patients with LA-SEC than in the controls. The mean left atrial dimension (41.32 ± 5.12 mm vs. 36.12 ± 5.66 mm, P < 0.001) was markedly larger in patients with LA-SEC. In multivariate regression analysis, SUA level was an independent risk factor for LA-SEC (OR: 1.008, P < 0.001). In receiver operating characteristic curve analysis, the corresponding area under the curve for SUA predicting LA-SEC in female and male were 0.670 and 0.657, respectively. SUA level is significantly higher in non-valvular AF patients with LA-SEC. Conclusion SUA level is an independent risk factor and has a moderate predictive value for LA-SEC among non-valvular AF patients in Southern China. PMID:26788041

  16. 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.

  17. STS-74/Mir photogrammetric appendage structural dynamics experiment

    NASA Technical Reports Server (NTRS)

    Welch, Sharon S.; Gilbert, Michael G.

    1996-01-01

    The Photogrammetric Appendage Structural Dynamics Experiment (PASDE) is an International Space Station (ISS) Phase-1 risk mitigation experiment. Phase-1 experiments are performed during docking missions of the U.S. Space Shuttle to the Russian Space Station Mir. The purpose of the experiment is to demonstrate the use of photogrammetric techniques for determination of structural dynamic mode parameters of solar arrays and other spacecraft appendages. Photogrammetric techniques are a low cost alternative to appendage mounted accelerometers for the ISS program. The objective of the first flight of PASDE, on STS-74 in November 1995, was to obtain video images of Mir Kvant-2 solar array response to various structural dynamic excitation events. More than 113 minutes of high quality structural response video data was collected during the mission. The PASDE experiment hardware consisted 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, fabricated, and tested at the NASA Langley Research Center in eight months. The flight hardware was integrated into standard Hitchhiker canisters at the NASA Goddard Space Flight Center and then installed into the Space Shuttle cargo bay in locations selected to achieve good video coverage and photogrammetric geometry.

  18. Delineating a conserved genetic cassette promoting outgrowth of body appendages.

    PubMed

    Lin, Congxing; Yin, Yan; Bell, Sheila M; Veith, G Michael; Chen, Hong; Huh, Sung-Ho; Ornitz, David M; Ma, Liang

    2013-01-01

    The acquisition of the external genitalia allowed mammals to cope with terrestrial-specific reproductive needs for internal fertilization, and thus it represents one of the most fundamental steps in evolution towards a life on land. How genitalia evolved remains obscure, and the key to understanding this process may lie in the developmental genetics that underpins the early establishment of the genital primordium, the genital tubercle (GT). Development of the GT is similar to that of the limb, which requires precise regulation from a distal signaling epithelium. However, whether outgrowth of the GT and limbs is mediated by common instructive signals remains unknown. In this study, we used comprehensive genetic approaches to interrogate the signaling cascade involved in GT formation in comparison with limb formation. We demonstrate that the FGF ligand responsible for GT development is FGF8 expressed in the cloacal endoderm. We further showed that forced Fgf8 expression can rescue limb and GT reduction in embryos deficient in WNT signaling activity. Our studies show that the regulation of Fgf8 by the canonical WNT signaling pathway is mediated in part by the transcription factor SP8. Sp8 mutants elicit appendage defects mirroring WNT and FGF mutants, and abolishing Sp8 attenuates ectopic appendage development caused by a gain-of-function β-catenin mutation. These observations indicate that a conserved WNT-SP8-FGF8 genetic cassette is employed by both appendages for promoting outgrowth, and suggest a deep homology shared by the limb and external genitalia. PMID:23358455

  19. Computed tomography model-based treatment of atrial fibrillation and atrial macro-re-entrant tachycardia

    PubMed Central

    Piorkowski, Christopher; Kircher, Simon; Arya, Arash; Gaspar, Thomas; Esato, Masahiro; Riahi, Sam; Bollmann, Andreas; Husser, Daniela; Staab, Charlotte; Sommer, Philipp; Hindricks, Gerhard

    2008-01-01

    Aims Accurate orientation within true three-dimensional (3D) anatomies is essential for the successful radiofrequency (RF) catheter ablation of atrial fibrillation (AF) and atrial macro-re-entrant tachycardia (MRT). In this prospective study, ablation of AF and MRT was performed exclusively using a pre-acquired and integrated computed tomography (CT) image for anatomical 3D orientation without electro-anatomic reconstruction of the left atrium (LA). Methods and results Fifty-four consecutive patients suffering from AF (n = 36) and/or MRT (n = 18) underwent RF catheter ablation. A 3D CT image was registered into the NavX-Ensite system without reconstruction of the atrial chamber anatomy. The quality of CT alignment was assessed and validated according to fluoroscopy information, electrogram characteristics, and tactile feedback at 31 pre-defined LA control points. The ablation of AF as well as mapping and ablation of MRT was performed within the 3D CT anatomy. In all patients, mapping and ablation could be performed without the reconstruction of the respective atrial chamber anatomy. The overall CT alignment was highly accurate with true surface contact in 90% (84%; 100%) of the control points. Complete isolation of all pulmonary vein (PV) funnels was achieved in 35 of 36 patients (97%) with AF. In patients with persistent AF (n = 11), additional isolation of the posterior LA (box lesion) and the placement of a mitral isthmus line were performed. The MRT mechanisms were as follows: around a PV ostium (n = 6), perimitral (n = 4), through LA roof (n = 5), septal (n = 2), and around left atrial appendage (n = 1). After a follow-up of 122 ± 33 days, 22/25 (88%) patients with paroxysmal AF, 8/11 (73%) with persistent AF, and 16/18 (89%) with MRT remained free from arrhythmia recurrences. Conclusion For patients with AF and MRT, our study shows the feasibility of successful placement of complex linear ablation line concepts guided by an integrated 3D image anatomy alone

  20. 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. PMID:21437328

  1. 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

  2. Targeted Deep Sequencing Reveals No Definitive Evidence for Somatic Mosaicism in Atrial Fibrillation

    PubMed Central

    Roberts, Jason D.; Longoria, James; Poon, Annie; Gollob, Michael H.; Dewland, Thomas A.; Kwok, Pui-Yan; Olgin, Jeffrey E.; Deo, Rahul C.; Marcus, Gregory M.

    2015-01-01

    Background Studies of ≤15 atrial fibrillation (AF) patients have identified atrial-specific mutations within connexin genes, suggesting that somatic mutations may account for sporadic cases of the arrhythmia. We sought to identify atrial somatic mutations among patients with and without AF using targeted deep next-generation sequencing of 560 genes, including genetic culprits implicated in AF, the Mendelian cardiomyopathies and channelopathies, and all ion channels within the genome. Methods and Results Targeted gene capture and next generation sequencing were performed on DNA from lymphocytes and left atrial appendages of 34 patients (25 with AF). Twenty AF patients had undergone cardiac surgery exclusively for pulmonary vein isolation, and 17 had no structural heart disease. Sequence alignment and variant calling were performed for each atrial-lymphocyte pair using the Burrows-Wheeler Aligner, the Genome Analysis Toolkit, and MuTect packages. Next generation sequencing yielded a median 265-fold coverage depth (IQR 164–369). Comparison of the 3 million base pairs from each atrial-lymphocyte pair revealed a single potential somatic missense mutation in 3 AF patients and 2 in a single control (12 vs. 11%; p=1). All potential discordant variants had low allelic fractions (range: 2.3–7.3%) and none were detected with conventional sequencing. Conclusions Using high-depth next generation sequencing and state-of-the art somatic mutation calling approaches, no pathogenic atrial somatic mutations could be confirmed among 25 AF patients in a comprehensive cardiac arrhythmia genetic panel. These findings indicate that atrial specific mutations are rare and that somatic mosaicism is unlikely to exert a prominent role in AF pathogenesis. PMID:25406240

  3. Atrial fibrillation or flutter

    MedlinePlus

    ... the mitral valve) Hypertension Medicines Overactive thyroid gland ( hyperthyroidism ) Pericarditis Sick sinus syndrome Symptoms You may not ... procedures Heart attack Heart pacemaker High blood pressure Hyperthyroidism Pericarditis Pulse Stable angina Stroke Patient Instructions Atrial ...

  4. What Is Atrial Fibrillation?

    MedlinePlus

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

  5. Multifocal atrial tachycardia

    MedlinePlus

    ... atrial tachycardia (MAT), many locations in the atria fire signals at the same time. Too many signals ... people with conditions that lower the amount of oxygen in the blood. These conditions include: Bacterial pneumonia ...

  6. 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 ...

  7. Anti-thromboembolic strategies in atrial fibrillation.

    PubMed

    Cocco, Giuseppe; Amiet, Philpp; Jerie, Paul

    2016-01-01

    Oral anticoagulation (OAC) is highly effective for stroke prevention in high-risk-patients with atrial fibrillation (AF). AF is also a risk for dementia, and effective OAC reduces the risk of dementia. Up to 30% of patients with AF have a coronary artery disease and antiplatelets are used to avoid thrombotic complications. Patients with AF often have an acute coronary syndrome (ACS) and undergo a percutaneous intervention with stent-implantation. These patients require a triple therapy, i.e. the combination of OAC with dual-antiplatelet therapy. It is obvious that OAC may induce bleeding with potentially deleterious effects on mortality. Even the occurrence of minor bleeding is problematic. The review describes available data on used anti-thromboembolic regimens in patients treated with OAC (vitamin K antagonists and non-vitamin K antagonists) who need a triple therapy (i.e. anticoagulation and antiplatelets). Most data are from patients who were treated for an ACS and cannot be directly extrapolated for patients with AF. The impact of used stents and novel P2Y12 antagonist-antiplatelets and duration of triple therapy is discussed. Often some high-risk patients with AF would need anticoagulation but cannot be given this therapy be-cause of excessive bleeding risks or contraindicating comorbidities: in these patients left atrial appendage closure with an occluding device can be used as an alternative to anti-thromboem-bolic therapy. The unavoidable anti-thromboembolic triple therapy carries a strong potential for bleeding events, which increase mortality. We have many data and several recommendations are offered. Nonetheless, we lack solid data on the best anti-thromboembolic regimen in patients with AF who need anticoagulation and antiplatelets. PMID:26779967

  8. Chemical-induced atrial thrombosis in NTP rodent studies.

    PubMed

    Yoshizawa, Katsuhiko; Kissling, Grace E; Johnson, Jo Anne; Clayton, Natasha P; Flagler, Norris D; Nyska, Abraham

    2005-01-01

    Cardiac thrombosis, one of the causes of sudden death throughout the world, plays a principal role in several cardiovascular diseases, such as myocardial infarction and stroke in humans. Data from studies of induction of chemical thrombosis in rodents help to identify substances in our environment that may contribute to cardiac thrombosis. Results for more than 500 chemicals tested in rodents in 2-year bioassays have been published as Technical Reports of the National Toxicology Program (NTP) http://ntp-server.niehs.nih.gov/index. We evaluated atrial thrombosis induced by these chemical exposures and compared it to similarly induced lesions reported in the literature. Spontaneous rates of cardiac thrombosis were determined for control Fischer 344 rats and B6C3F1 mice: 0% in rats and mice in 90-day studies and, in 2-year studies, 0.7% in both genders of mice, 4% in male rats, and 1% in female rats. Incidences of atrial thrombosis were increased in high-dosed groups involving 13 compounds (incidence rate: 20-100%): 2-butoxyethanol, C.I. Direct Blue 15, bis(2-chloroethoxy)methane, diazoaminobenzene, diethanolamine, 3,3'-dimethoxybenzidine dihydrochloride, hexachloroethane, isobutene, methyleugenol, oxazepam, C.I. Pigment Red 23, C.I. Acid Red 114, and 4,4'-thiobis(6-t-butyl-m-cresol). The main localization of spontaneously occurring and chemically induced thromboses occurred in the left atrium. The literature survey suggested that chemical-induced atrial thrombosis might be closely related to myocardial injury, endothelial injury, circulatory stasis, hypercoagulability, and impaired atrial mechanical activity, such as atrial fibrillation, which could cause stasis of blood within the left atrial appendage, contributing to left atrial thrombosis. Supplementary data referenced in this paper are not printed in this issue of Toxicologic Pathology. They are available as downloadable files at http://taylorandfrancis.metapress.com/openurl.asp?genre=journal&issn=0192-6233. To

  9. MRI of the left atrium: predicting clinical outcomes in patients with atrial fibrillation.

    PubMed

    Daccarett, Marcos; McGann, Chris J; Akoum, Nazem W; MacLeod, Rob S; Marrouche, Nassir F

    2011-01-01

    Atrial fibrillation is a significant public health burden, with clinically, epidemiologically and economically significant repercussions. In the last decade, catheter ablation has provided an improvement in morbidity and quality of life, significantly reducing long-term healthcare costs and avoiding recurrences compared with drug therapy. Despite recent progress in techniques, current catheter ablation success rates fall short of expectations. Late gadolinium-enhancement cardiovascular MRI is a well-established tool to image the myocardium and, most specifically, the left atrium. Unique imaging protocols allow for left atrial structural remodeling and fibrosis assessment, which has been demonstrated to correlate with clinical outcomes after catheter ablation, assessment of the individual's risks of thromboembolic events, and effective imaging of patients with left atrial appendage thrombus. Late gadolinium-enhancement MRI aids in the individualized treatment of atrial fibrillation, stratifying recurrence risk and guiding specific ablation strategies. Real-time MRI offers significant safety and effectiveness profiles that would optimize the invasive treatment of atrial fibrillation. PMID:21166532

  10. 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

  11. Atrial remodeling, fibrosis, and atrial fibrillation.

    PubMed

    Jalife, José; Kaur, Kuljeet

    2015-08-01

    The fundamental mechanisms governing the perpetuation of atrial fibrillation (AF), the most common arrhythmia seen in clinical practice, are poorly understood, which explains in part why AF prevention and treatment remain suboptimal. Although some clinical parameters have been identified as predicting a transition from paroxysmal to persistent AF in some patients, the molecular, electrophysiological, and inflammation changes leading to such a progression have not been described in detail. Oxidative stress, atrial dilatation, calcium overload, inflammation, microRNAs, and myofibroblast activation are all thought to be involved in AF-induced atrial remodeling. However, it is unknown to what extent and at which time points such alterations influence the remodeling process that perpetuates AF. Here we postulate a working model that might open new pathways for future investigation into mechanisms of AF perpetuation. We start from the premise that the progression to AF perpetuation is the result of interplay among manifold signaling pathways with differing kinetics. Some such pathways have relatively fast kinetics (e.g., oxidative stress-mediated shortening of refractory period); others likely depend on molecular processes with slower kinetics (e.g., transcriptional changes in myocyte ion channel protein expression mediated through inflammation and fibroblast activation). We stress the need to fully understand the relationships among such pathways should one hope to identify novel, truly effective targets for AF therapy and prevention. PMID:25661032

  12. Atrial selectivity of antiarrhythmic drugs

    PubMed Central

    Ravens, Ursula; Poulet, Claire; Wettwer, Erich; Knaut, Michael

    2013-01-01

    New antiarrhythmic drugs for treatment of atrial fibrillation should ideally be atrial selective in order to avoid pro-arrhythmic effects in the ventricles. Currently recognized atrial selective targets include atrial Nav1.5 channels, Kv1.5 channels and constitutively active Kir3.1/3.4 channels, each of which confers atrial selectivity by different mechanisms. Na+ channel blockers with potential- and frequency-dependent action preferentially suppress atrial fibrillation because of the high excitation rate and less negative atrial resting potential, which promote drug binding in atria. Kv1.5 channels are truly atrial selective because they do not conduct repolarizing current IKur in ventricles. Constitutively active IK,ACh is predominantly observed in remodelled atria from patients in permanent atrial fibrillation (AF). A lot of effort has been invested to detect compounds which will selectively block Kir3.1/Kir3.4 in their remodelled constitutively active form. Novel drugs which have been and are being developed aim at atrial-selective targets. Vernakalant and ranolazine which mainly block atrial Na+ channels are clinically effective. Newly designed selective IKur blockers and IK,ACh blockers are effective in animal models; however, clinical benefit in converting AF into sinus rhythm (SR) or reducing AF burden remains to be demonstrated. In conclusion, atrial-selective antiarrhythmic agents have a lot of potential, but a long way to go. PMID:23732646

  13. Atrial Fibrillation (AF or AFib)

    MedlinePlus

    ... Pressure High Blood Pressure Tools & Resources Stroke More Atrial Fibrillation (AF or AFib) Updated:Feb 10,2016 What ... to the Terms and Conditions and Privacy Policy Atrial Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters • ...

  14. Atrial natriuretic factor and postnatal diuresis in respiratory distress syndrome.

    PubMed Central

    Rozycki, H J; Baumgart, S

    1991-01-01

    To find out if atrial natriuretic factor plays a part in the control of urine output during the initiation alone or throughout postnatal diuresis in neonates with respiratory distress syndrome, atrial natriuretic factor concentrations and clinical and renal variables were measured prospectively three times during the first three days of life in 13 premature infants. Atrial natriuretic factor concentrations rose significantly between the first and second sample times as did the urine output and output:input ratio. By the time that the third sample was taken, atrial natriuretic factor concentration had decreased significantly since the second sample had been taken, while urine flow was maintained. All subjects initiated a spontaneous diuresis that was related to the second concentration of atrial natriuretic factor. With partial correlation analysis a significant relationship was shown between the concentration of atrial natriuretic factor and the maintenance of urine output throughout the study period. Individual hormone concentrations did not, however, correlate with simultaneous renal variables. Changes in the concentrations of atrial natriuretic factor coincided with initiation of spontaneous diuresis in babies with respiratory distress syndrome, and may have a role in the complex mechanisms that maintain this diuresis. PMID:1825462

  15. Anticoagulation in atrial fibrillation

    PubMed Central

    Piccini, Jonathan P

    2014-01-01

    Atrial fibrillation increases the risk of stroke, which is a leading cause of death and disability worldwide. The use of oral anticoagulation in patients with atrial fibrillation at moderate or high risk of stroke, estimated by established criteria, improves outcomes. However, to ensure that the benefits exceed the risks of bleeding, appropriate patient selection is essential. Vitamin K antagonism has been the mainstay of treatment; however, newer drugs with novel mechanisms are also available. These novel oral anticoagulants (direct thrombin inhibitors and factor Xa inhibitors) obviate many of warfarin’s shortcomings, and they have demonstrated safety and efficacy in large randomized trials of patients with non-valvular atrial fibrillation. However, the management of patients taking warfarin or novel agents remains a clinical challenge. There are several important considerations when selecting anticoagulant therapy for patients with atrial fibrillation. This review will discuss the rationale for anticoagulation in patients with atrial fibrillation; risk stratification for treatment; available agents; the appropriate implementation of these agents; and additional, specific clinical considerations for treatment. PMID:24733535

  16. Anticoagulation in atrial fibrillation.

    PubMed

    Steinberg, Benjamin A; Piccini, Jonathan P

    2014-01-01

    Atrial fibrillation increases the risk of stroke, which is a leading cause of death and disability worldwide. The use of oral anticoagulation in patients with atrial fibrillation at moderate or high risk of stroke, estimated by established criteria, improves outcomes. However, to ensure that the benefits exceed the risks of bleeding, appropriate patient selection is essential. Vitamin K antagonism has been the mainstay of treatment; however, newer drugs with novel mechanisms are also available. These novel oral anticoagulants (direct thrombin inhibitors and factor Xa inhibitors) obviate many of warfarin's shortcomings, and they have demonstrated safety and efficacy in large randomized trials of patients with non-valvular atrial fibrillation. However, the management of patients taking warfarin or novel agents remains a clinical challenge. There are several important considerations when selecting anticoagulant therapy for patients with atrial fibrillation. This review will discuss the rationale for anticoagulation in patients with atrial fibrillation; risk stratification for treatment; available agents; the appropriate implementation of these agents; and additional, specific clinical considerations for treatment. PMID:24733535

  17. Co-occurrence of carbohydrate malabsorption and primary epiploic appendagitis

    PubMed Central

    Schnedl, Wolfgang J; Kalmar, Peter; Mangge, Harald; Krause, Robert; Wallner-Liebmann, Sandra J

    2015-01-01

    Unspecific abdominal complaints including bloating and irregular bowel movements may be caused by carbohydrate malabsorption syndromes, e.g., lactose and fructose malabsorption. These symptoms were investigated with hydrogen (H2) breath tests and correlated to carbohydrate malabsorption. During performing these H2-breath tests the patient presented with an acute, localized, non-migratory pain in the left lower abdominal quadrant. Primary epiploic appendagitis is a rare cause of abdominal acute or subacute complaints and diagnosis of primary epiploic appendagitis (PEA) is made when computed tomography reveals a characteristic lesion. We report on a patient with co-occurrence of lactose and fructose malabsorption, which was treated successfully with a diet free of culprit carbohydrates, with PEA recovering without medication or surgical treatment within few days. Since the abdominal unspecific symptoms had been present for months, they appeared not to be correlated to the acute localized abdominal pain, therefore we speculate on a random co-occurrence of combined carbohydrate malabsorption and PEA. PMID:26401090

  18. Co-occurrence of carbohydrate malabsorption and primary epiploic appendagitis.

    PubMed

    Schnedl, Wolfgang J; Kalmar, Peter; Mangge, Harald; Krause, Robert; Wallner-Liebmann, Sandra J

    2015-09-21

    Unspecific abdominal complaints including bloating and irregular bowel movements may be caused by carbohydrate malabsorption syndromes, e.g., lactose and fructose malabsorption. These symptoms were investigated with hydrogen (H2) breath tests and correlated to carbohydrate malabsorption. During performing these H2-breath tests the patient presented with an acute, localized, non-migratory pain in the left lower abdominal quadrant. Primary epiploic appendagitis is a rare cause of abdominal acute or subacute complaints and diagnosis of primary epiploic appendagitis (PEA) is made when computed tomography reveals a characteristic lesion. We report on a patient with co-occurrence of lactose and fructose malabsorption, which was treated successfully with a diet free of culprit carbohydrates, with PEA recovering without medication or surgical treatment within few days. Since the abdominal unspecific symptoms had been present for months, they appeared not to be correlated to the acute localized abdominal pain, therefore we speculate on a random co-occurrence of combined carbohydrate malabsorption and PEA. PMID:26401090

  19. A method for immunolabeling neurons in intact cuticularized insect appendages.

    PubMed

    Ehrhardt, Erica; Kleele, Tatjana; Boyan, George

    2015-06-01

    The antennae of the grasshopper Schistocerca gregaria possess a pair of nerve pathways which are established by so-called pioneer neurons early in embryonic development. Subsequently, sensory cell clusters mediating olfaction, flight, optomotor responses, and phase changes differentiate from the antennal epithelium at stereotypic locations and direct their axons onto those of the pioneers to then project to the brain. Early in embryonic development, before the antennae become cuticularized, immunolabeling can be used to follow axogenesis in these pioneers and sensory cells. At later stages, immunolabeling becomes problematical as the cuticle is laid down and masks internal antigen sites. In order to immunolabel the nervous system of cuticularized late embryonic and first instar grasshopper antennae, we modified a procedure known as sonication in which the appendage is exposed to ultrasound thereby rendering it porous to antibodies. Comparisons of the immunolabeled nervous system of sectioned and sonicated antennae show that the cellular organization of sensory clusters and their axon projections is intact. The expression patterns of neuron-specific, microtubule-specific, and proliferative cell-specific labels in treated antennae are consistent with those reported for earlier developmental stages where sonication is not necessary, suggesting that these molecular epitopes are also conserved. The method ensures reliable immunolabeling in intact, cuticularized appendages so that the peripheral nervous system can be reconstructed directly via confocal microscopy throughout development. PMID:25868908

  20. Right atrial spleen.

    PubMed Central

    Kuijer, P; Dion, R; van Merrienboer, F

    1985-01-01

    A large cardiac tumour occupying most of the right atrium and the right ventricle and causing inflow obstruction to the right heart was confirmed by cross sectional echocardiography in a 41 year old man. After surgical resection histological examination showed that the atrial tumour had the characteristics of splenic tissue. Possible mechanisms for the development of such a tumour include an origin analogous to that of an accessory spleen or the implantation and subsequent growth of lymphoid tissue in a pre-existing superior vena caval or high right atrial angioma. Images PMID:4041304

  1. Two appendages homologous between basal bodies and centrioles are formed using distinct Odf2 domains

    PubMed Central

    Tateishi, Kazuhiro; Yamazaki, Yuji; Nishida, Tomoki; Watanabe, Shin; Kunimoto, Koshi; Ishikawa, Hiroaki

    2013-01-01

    Ciliogenesis is regulated by context-dependent cellular cues, including some transduced through appendage-like structures on ciliary basal bodies called transition fibers and basal feet. However, the molecular basis for this regulation is not fully understood. The Odf2 gene product, ODF2/cenexin, is essential for both ciliogenesis and the formation of the distal and subdistal appendages on centrioles, which become basal bodies. We examined the effects of Odf2 deletion constructs on ciliogenesis in Odf2-knockout F9 cells. Electron microscopy revealed that ciliogenesis and transition fiber formation required the ODF2/cenexin fragment containing amino acids (aa) 188–806, whereas basal foot formation required aa 1–59 and 188–806. These sequences also formed distal and subdistal appendages, respectively, indicating that the centriole appendages are molecularly analogous to those on basal bodies. We used the differential formation of appendages by Odf2 deletion constructs to study the incorporation and function of molecules associated with each appendage type. We found that transition fibers and distal appendages were required for ciliogenesis and subdistal appendages stabilized the centrosomal microtubules. PMID:24189274

  2. The homeobox gene Distal-less induces ventral appendage development in Drosophila

    PubMed Central

    Gorfinkiel, Nicole; Morata, Ginés; Guerrero, Isabel

    1997-01-01

    This study investigates the role of the homeobox gene Distal-less (Dll) in the development of the legs, antennae, and wings of Drosophila. Lack of Dll function causes a change in the identity of ventral appendage cells (legs and antennae) that often results in the loss of the appendage. Ectopic Dll expression in the proximal region of ventral appendages induces nonautonomous duplication of legs and antennae by the activation of wingless and decapentaplegic. Ectopic Dll expression in dorsal appendages produces transformation into corresponding ventral appendages; wings and halteres develop ectopic legs and the head–eye region develops ectopic antennae. In the wing, the exogenous Dll product induces this transformation by activating the endogenous Dll gene and repressing the wing determinant gene vestigial. It is proposed that Dll induces the development of ventral appendages and also participates in a genetic address that specifies the identity of ventral appendages and discriminates the dorsal versus the ventral appendages in the adult. However, unlike other homeotic genes, Dll expression and function is not defined by a cell lineage border. Dll also performs a secondary and late function required for the normal patterning of the wing. PMID:9303541

  3. Dynamics, analytical solutions and choice of parameters for towed space debris with flexible appendages

    NASA Astrophysics Data System (ADS)

    Aslanov, Vladimir S.; Yudintsev, Vadim V.

    2015-01-01

    Active debris removal is one of the promising techniques that will decrease the population of large, non-functional spacecraft (space debris) on orbit. Properties of space debris should be taken into account during planning an active debris removal mission. In this paper the thrusting phase of tethered deorbit of large space debris with flexible appendages is considered. The goal of the work is to investigate the mutual influence of the tether vibrations and the vibrations of flexible appendages during thrusting phase. A mathematical model of the space tug and the towed space debris with flexible appendages is developed. Parameters of the system are determined with assumptions that the system is moving in straight line, avoiding high amplitude vibrations of flexible appendages. The expression of the discriminant indicates that the vibrations of the tether and flexible appendages influence each other. A critical tether stiffness exists for the given space tug mass that should be avoided.

  4. 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.

  5. 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.

  6. 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

    2015-06-01

    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

  7. 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

  8. 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

  9. 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

  10. Systematic Analysis of Gene Expression Differences between Left and Right Atria in Different Mouse Strains and in Human Atrial Tissue

    PubMed Central

    Fabritz, Larissa; Greber, Boris; Schöler, Hans; Scheld, Hans H.; Hoffmeier, Andreas; Brown, Nigel A.; Kirchhof, Paulus

    2011-01-01

    Background Normal development of the atria requires left-right differentiation during embryonic development. Reduced expression of Pitx2c (paired-like homeodomain transcription factor 2, isoform c), a key regulator of left-right asymmetry, has recently been linked to atrial fibrillation. We therefore systematically studied the molecular composition of left and right atrial tissue in adult murine and human atria. Methods We compared left and right atrial gene expression in healthy, adult mice of different strains and ages by employing whole genome array analyses on freshly frozen atrial tissue. Selected genes with enriched expression in either atrium were validated by RT-qPCR and Western blot in further animals and in shock-frozen left and right atrial appendages of patients undergoing open heart surgery. Results We identified 77 genes with preferential expression in one atrium that were common in all strains and age groups analysed. Independent of strain and age, Pitx2c was the gene with the highest enrichment in left atrium, while Bmp10, a member of the TGFβ family, showed highest enrichment in right atrium. These differences were validated by RT-qPCR in murine and human tissue. Western blot showed a 2-fold left-right concentration gradient in PITX2 protein in adult human atria. Several of the genes and gene groups enriched in left atria have a known biological role for maintenance of healthy physiology, specifically the prevention of atrial pathologies involved in atrial fibrillation, including membrane electrophysiology, metabolic cellular function, and regulation of inflammatory processes. Comparison of the array datasets with published array analyses in heterozygous Pitx2c+/− atria suggested that approximately half of the genes with left-sided enrichment are regulated by Pitx2c. Conclusions Our study reveals systematic differences between left and right atrial gene expression and supports the hypothesis that Pitx2c has a functional role in maintaining

  11. 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

  12. An uncommon complication of atrial fibrillation

    PubMed Central

    Mallouppas, Michael; Christopoulos, Christos; Watson, Will; Cader, Ruzaika; Cooper, John

    2015-01-01

    Coronary embolism is a well-recognized cause of myocardial infarction. It is often under diagnosed and cardiologists need to be vigilant for this diagnosis. A 77-year-old man presented with chest pain with an ECG showing a new diagnosis of atrial fibrillation. Owing to ongoing chest pain coronary angiography was performed and revealed an acute occlusion of the left circumflex artery with coronary blood flow restored following aspiration of a large red thrombus. Following this the coronary vessel looked smooth with no residual coronary lesions requiring angioplasty or plaque rupture to justify the thrombosis. The clinical picture and angiographic data suggested the coronary embolus was secondary to the newly diagnosed atrial fibrillation.

  13. Differential atrial filling after Mustard and Senning repairs. Detection by transcutaneous Doppler ultrasound.

    PubMed Central

    Wyse, R K; Macartney, F J; Rohmer, J; Ottenkamp, J; Brom, A G

    1980-01-01

    The dominance of Mustard's operation for transposition of the great arteries has been challenged by the recent revival of Senning's repair because it promises better long-term results in terms of venous obstruction and atrial haemodynamics. These hypotheses were tested by recording jugular venous flow waveforms transcutaneously in 24 postoperative patients with simple complete transposition using a bidirectional Doppler blood velocimeter. Eight patients had undergone Mustard's operation and 16 the Senning alternative; all had previously had a postoperative cardiac catheterisation. Both groups of patients had similar left ventricular, pulmonary arterial, and systemic venous atrial pressures. No child showed any evidence at catheterisation of either mitral regurgitation or of superior vena caval pathway obstruction. These two findings were endorsed by the transcutaneous Doppler recordings. Jugular venous flow in normal children exhibits two maxima, one of atrial filling during ventricular systole, the other of ventricular filling occurs once the tricuspid valve has opened. Both operative procedures diminished the size of the former phase, but the Mustard did so more. After Mustard's operation forward flow during the atrial filling phase was absent in approximately half the cardiac cycles recorded, and severely diminished in the rest. By contrast, there was approximately a 90 per cent appearance of atrial filling waves after Senning's operation which also provided significantly better atrial function than Mustard's procedure in terms of peak velocity of blood entering the atrium and total atrial filling. It is therefore concluded that both procedures compromise atrial volume and compliance but Senning's repair to a much lesser extent. PMID:7459153

  14. Clinical implications of atrial isomerism.

    PubMed Central

    Chiu, I S; How, S W; Wang, J K; Wu, M H; Chu, S H; Lue, H C; Hung, C R

    1988-01-01

    Right atrial isomerism or left atrial isomerism is frequently diagnosed as situs ambiguous without further discrimination of the specific morbid anatomy. Thirty six cases of right atrial isomerism and seven cases of left atrial isomerism were collected from the records and pathological museum at the National Taiwan University Hospital. There was a necropsy report for 18 cases. In all patients one or more of the following conditions was met: (a) isomeric bronchial anatomy, (b) echocardiographic and angiocardiographic evidence of isomerism, and (c) surgical or necropsy evidence of abnormal atrial anatomy. An anomalous pulmonary venous connection was present in 55% of patients with right atrial isomerism; in left atrial isomerism one case (14%) had a partial anomalous pulmonary venous connection. Forty per cent of cases of anomalous pulmonary venous connection with right atrial isomerism had obstruction. Six (86%) of seven cases with left atrial isomerism had an ambiguous biventricular atrioventricular connection. In contrast, univentricular atrioventricular connection (26 of 36, 72%) was significantly more common in right atrial isomerism. A common atrioventricular valve was the most frequent mode of connection in both forms. Two discrete atrioventricular valves were significantly more common in left atrial isomerism. Atrioventricular valve regurgitation was detected in 14 cases. Double outlet right ventricle was the most common type of ventriculoarterial connection. The most commonly cited causes of death after either palliative or definitive operation were undetected anomalous pulmonary venous connection, pulmonary venous stricture, and uncorrected atrioventricular valve or aortic regurgitation complicated by abnormal coagulation. Although the prognosis is poor, successful operation depends on knowledge of the precise anatomical arrangement associated with atrial isomerism. Images Fig 1 Fig 2 Fig 3 PMID:3408620

  15. MMP9 Rs3918242 Polymorphism Affects Tachycardia-Induced MMP9 Expression in Cultured Atrial-Derived Myocytes but Is Not a Risk Factor for Atrial Fibrillation among the Taiwanese.

    PubMed

    Hsiao, Fu-Chih; Yeh, Yung-Hsin; Chen, Wei-Jan; Chan, Yi-Hsin; Kuo, Chi-Tai; Wang, Chun-Li; Chang, Chi-Jen; Tsai, Hsin-Yi; Tsai, Feng-Chun; Hsu, Lung-An

    2016-01-01

    Matrix metalloproteinase (MMP) plays an important role in the pathogenesis of atrial fibrillation (AF). The MMP9 promoter has a functional polymorphism rs3918242 that can regulate the level of gene transcription. This study recruited 200 AF patients and 240 controls. The MMP9 rs3918242 was examined by polymerase chain reactions. HL-1 atrial myocytes were cultured and electrically stimulated. Right atrial appendages were obtained from six patients with AF and three controls with sinus rhythm undergoing open heart surgery. The MMP9 expression and activity were determined using immunohistochemical analysis and gelatin zymography, respectively. Rapid pacing induces MMP9 secretion from HL-1 myocytes in a time- and dose-dependent manner. The responsiveness of MMP9 transcriptional activity to tachypacing was significantly enhanced by rs3918242. The expression of MMP9 was increased in fibrillating atrial tissue than in sinus rhythm. However, the distribution of rs3918242 genotypes and allele frequencies did not significantly differ between the control and AF groups. HL-1 myocyte may secrete MMP9 in response to rapid pacing, and the secretion could be modulated by rs3918242. Although the MMP9 expression of human atrial myocyte is associated with AF, our study did not support the association of susceptibility to AF among Taiwanese subjects with the MMP9 rs3918242 polymorphism. PMID:27070579

  16. MMP9 Rs3918242 Polymorphism Affects Tachycardia-Induced MMP9 Expression in Cultured Atrial-Derived Myocytes but Is Not a Risk Factor for Atrial Fibrillation among the Taiwanese

    PubMed Central

    Hsiao, Fu-Chih; Yeh, Yung-Hsin; Chen, Wei-Jan; Chan, Yi-Hsin; Kuo, Chi-Tai; Wang, Chun-Li; Chang, Chi-Jen; Tsai, Hsin-Yi; Tsai, Feng-Chun; Hsu, Lung-An

    2016-01-01

    Matrix metalloproteinase (MMP) plays an important role in the pathogenesis of atrial fibrillation (AF). The MMP9 promoter has a functional polymorphism rs3918242 that can regulate the level of gene transcription. This study recruited 200 AF patients and 240 controls. The MMP9 rs3918242 was examined by polymerase chain reactions. HL-1 atrial myocytes were cultured and electrically stimulated. Right atrial appendages were obtained from six patients with AF and three controls with sinus rhythm undergoing open heart surgery. The MMP9 expression and activity were determined using immunohistochemical analysis and gelatin zymography, respectively. Rapid pacing induces MMP9 secretion from HL-1 myocytes in a time- and dose-dependent manner. The responsiveness of MMP9 transcriptional activity to tachypacing was significantly enhanced by rs3918242. The expression of MMP9 was increased in fibrillating atrial tissue than in sinus rhythm. However, the distribution of rs3918242 genotypes and allele frequencies did not significantly differ between the control and AF groups. HL-1 myocyte may secrete MMP9 in response to rapid pacing, and the secretion could be modulated by rs3918242. Although the MMP9 expression of human atrial myocyte is associated with AF, our study did not support the association of susceptibility to AF among Taiwanese subjects with the MMP9 rs3918242 polymorphism. PMID:27070579

  17. Extracellular fluid translocation in perfused rabbit atria: implication in control of atrial natriuretic peptide secretion.

    PubMed Central

    Cho, K W; Kim, S H; Hwang, Y H; Seul, K H

    1993-01-01

    1. Transmural transport of 22Na+, 51Cr-EDTA, [3H]inulin and [14C]Dextran (57 kDa) was measured in perfused rabbit atria. The radiolabelled extracellular space (ECS) markers and [14C]Dextran were introduced into the pericardial space or atrial lumen. Atrial volume changes were induced by steps up and down in atrial pressure. 2. Basal rates of transmural transport of radiolabelled ECS markers across the atrial wall were relatively stable up to 70 min. Atrial stretch and release resulted in a rapid but transient, and reversible increase in the ECS fluid (ECF) translocation. The increased translocation of the ECF into the atrial lumen occurred within 15 s of the reduction of atrial distension and returned to the baseline level within 60 s. 3. Transmural transport of [3H]inulin across the atrial wall was bidirectional. 4. The clearance of radiolabelled ECS markers was molecular-size dependent. The transmural clearance of [3H]inulin was dependent on the distension-reduction volume changes induced by atrial stretch and release. Little transport of [14C]Dextran across the atrial wall was observed. 5. The ECF translocation across the atrial wall was not influenced by changes in external Ca2+ but was suppressed by low temperature. 6. Dynamic changes in the ECS of the atrium were observed in response to atrial distension and reduction. The ECS of the atrium increased on distension and decreased on reduction of atrial distension. 7. Reduction in atrial distension resulted in an increase in the secretion of immunoreactive atrial natriuretic peptide (ANP) which coincided with an increase in the translocation of the ECF. The secretion of immunoreactive ANP was a function of the translocation of the ECF. 8. It is suggested that atrial stretch and release may play a role in driving fluid flow within the interstitium and fluid translocation out of the interstitium. This fluid movement presumably leads to convective transport of released ANP into the atrial lumen. PMID:8254526

  18. Atrial fibrillation and inflammation

    PubMed Central

    Ozaydin, Mehmet

    2010-01-01

    Atrial fibrillation (AF) is the most common clinical arrhythmia. Recent investigations have suggested that inflammation might have a role in the pathophysiology of AF. In this review, the association between inflammation and AF, and the effects of several agents that have anti-inflammatory actions, such as statins, polyunsaturated fatty acids, corticosteroids and angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, have been investigated. PMID:21160591

  19. Atrial fibrillation case study.

    PubMed

    Johnson, Sarah; Wilson, Tracey

    2016-03-01

    This article discusses the irregular heart rhythm caused by atrial fibrillation (AF). A brief overview of the pathophysiology will be provided. A case study is discussed to highlight the treatment and management of AF. The care provision describes common signs and symptoms and also the treatment and management of AF within the maternity care setting. The importance of maintaining the mother-baby dyad is highlighted. For the purpose of maintaining confidentiality the woman will be referred to as Shama. PMID:27044188

  20. DISPARATE EVOLUTION OF RIGHT AND LEFT ATRIAL RATE DURING ABLATION OF LONG-LASTING PERSISTENT ATRIAL FIBRILLATION

    PubMed Central

    Hocini, Mélèze; Nault, Isabelle; Wright, Matthew; Veenhuyzen, George; Narayan, Sanjiv M.; Jaïs, Pierre; Lim, Kang-Teng; Knecht, Sébastien; Matsuo, Seiichiro; Forclaz, Andrei; Miyazaki, Shinsuke; Jadidi, Amir; O’Neill, Mark D.; Sacher, Frédéric; Clémenty, Jacques; Haïssaguerre, Michel

    2010-01-01

    Objectives To assess whether additional ablation in the right atrium(RA) improves termination rate in long-lasting persistent atrial fibrillation(PsAF). Background Prolongation of atrial fibrillation(AF) cycle length(CL) measured from the left atrial appendage predicts favorable outcome during catheter ablation of PsAF. However, in some patients despite prolongation of AFCL in the left atrium(LA) with ablation, AF persists. We hypothesized that this is due to RA drivers and these patients may benefit from RA ablation. Methods 148 consecutive patients undergoing catheter ablation of PsAF(duration 25±32 months) were studied. AFCL was monitored in both atria during stepwise ablation commencing in the LA. Ablation was performed in the RA when all LA sources in AF had been ablated and a RA-LA gradient existed. The procedural endpoint was AF termination. Results Two distinct patterns of AFCL change emerged during LA ablation. In 104patients(70%), there was parallel increase of AFCL in LA and RA culminating in AF termination (baseline: LA 153ms[140,170], RA 155ms[143,171]; after ablation: LA 181ms[170,200], RA 186ms[175,202]). In 24 patients(19%), RA AFCL did not prolong, creating a right-to-left frequency gradient, (baseline: LA 142ms[143,153], RA 145 ms[139,162]; after ablation: LA 177 ms[165–185], RA 152ms[147,175]). These patients had a longer AF history (23versus12 months, p=0.001), and larger RA diameter (42versus39mm, p=0.005) and RA ablation terminated AF in 55%. In the remaining 20 patients, biatrial ablation failed to terminate AF. Conclusions A divergent pattern of AFCL prolongation after LA ablation resulting in a right-to-left gradient demonstrating that the right atrium is driving AF in about 20 % of PsAF. PMID:20202517

  1. Hyperuricemia and Atrial Fibrillation.

    PubMed

    Maharani, Nani; Kuwabara, Masanari; Hisatome, Ichiro

    2016-07-27

    The importance of atrial fibrillation (AF) as a cause of mortality and morbidity has prompted research on its pathogenesis and treatment. Recognition of AF risk factors is essential to prevent it and reduce the risk of death. Hyperuricemia has been widely accepted to be associated with the incidence of paroxysmal or persistent AF, as well as to the risk of AF in post cardiovascular surgery patients. The possible explanations for this association have been based on their relation with either oxidative stress or inflammation. To investigate the link between hyperuricemia and AF, it is necessary to refer to hyperuricemia-induced atrial remodeling. So far, both ionic channel and structural remodeling caused by hyperuricemia might be plausible explanations for the occurrence of AF. Inhibition of xanthine oxidase and nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase, or the use of antioxidants, along with serum uric acid (SUA) level reduction to prevent inflammation, might be useful. Uric acid transporters (UATs) play a key role in the regulation of intracellular uric acid concentration. Intracellular rather than serum uric acid level is considered more important for the pathogenesis of AF. Identification of UATs expressed in cells is thus important, and targeting UATs might become a potential strategy to reduce the risk of hyperuricemia-induced atrial fibrillation. PMID:27396561

  2. Immunocytochemical localization of atrial natriuretic factor in the heart and salivary glands.

    PubMed

    Cantin, M; Gutkowska, J; Thibault, G; Milne, R W; Ledoux, S; MinLi, S; Chapeau, C; Garcia, R; Hamet, P; Genest, J

    1984-01-01

    Antibodies produced in the mouse by repeated intraperitoneal injections of partly purified atrial natriuretic factor (low molecular weight peptide (LMWP) and high molecular weight peptide (HMWP)) have been used to localize these factors by immunohistochemistry (immunofluorescence and immunoperoxidase method) and by immunocytochemistry (protein A-gold technique) in the heart of rats and of a variety of animal species including man and in the rat salivary glands. Immunofluorescence and the immunoperoxidase method gave identical results; in the rat, atrial cardiocytes gave a positive reaction at both nuclear poles while ventricular cardiocytes were consistently negative. The cardiocytes of the right atrial appendage were more intensely reactive than those localized in the left appendage. A decreasing gradient of intensity was observed from the subpericardial to the subendocardial cardiocytes. The cardiocytes of the interatrial septum were only lightly granulated. Sodium deficiency and thirst (deprivation of drinking water for 5 days) produced, as already shown at the ultrastructural level, a marked increase in the reactivity of all cardiocytes from both atria with the same gradient of intensity as in control animals. Cross-reactivity of intragranular peptides with the rat antibodies allowed visualization of specific granules in a variety of animal species (mouse, guinea pig, rabbit, rat, dog) and in human atrial appendages. No reaction could be elicited in the frog atrium and ventricle although, in this species, specific granules have been shown to be present by electron microscopy in all cardiac chambers. With the protein A-gold technique, at the ultrastructural level, single labeling (use of one antibody on one face of a fine section) or double labeling (use of two antibodies on the two faces of a fine section) showed that the two peptides are localized simultaneously in all three types (A, B and D) of specific granules. In the rat salivary glands

  3. Stroke in atrial fibrillation: update on pathophysiology, new antithrombotic therapies, and evolution of procedures and devices.

    PubMed

    Savelieva, Irina; Bajpai, Abhay; Camm, A John

    2007-01-01

    Atrial fibrillation (AF) is said to be an epidemic, affecting 1%-1.5% of the population in the developed world. The clinical significance of AF lies predominantly in a 5-fold increased risk of stroke. Strokes associated with AF are usually more severe and confer increased risk of morbidity, mortality, and poor functional outcome. Despite the advent of promising experimental therapies for selected patients with acute stroke, pharmacological primary prevention remains the best approach to reducing the burden of stroke. New antithrombotic drugs include both parenteral agents (e.g. a long-acting factor Xa inhibitor idraparinux) and oral anticoagulants, such as oral factor Xa inhibitors and direct oral thrombin inhibitors (ximelagatran, dabigatran). Ximelagatran had shown significant potential as a possible replacement to warfarin therapy, but has been withdrawn because of potential liver toxicity. Its congener dabigatran appears to have a better safety profile and has recently entered a phase III randomized clinical trial in AF. Oral factor Xa inhibitors (rivaroxaban, apixaban, YM150) inhibit factor Xa directly, without antithrombin III mediation, and may prove to be more potent and safe. Selective inhibitors of specific coagulation factors involved in the initiation and propagation of the coagulation cascade (factor IXa, factor VIIa, circulating tissue factor) are at an early stage of development. Additional new agents with hypothetical, although not yet proven, anticoagulation benefits include nematode anticoagulant peptide (NAPc2), protein C derivatives, and soluble thrombomodulin. A battery of novel mechanical approaches for the prevention of cardioembolic stroke has recently been evaluated, including various models of percutaneous left atrial appendage occluders which block the connection between the left atrium and the left atrial appendage, minimally invasive surgical isolation of the left atrial appendage, and implantation of the carotid filtering devices which

  4. [Catheter ablation of atrial flutter and paroxysmal atrial fibrillation].

    PubMed

    Márquez, Manlio F

    2003-01-01

    Radiofrequency catheter ablation has emerged as a curative therapy for atrial flutter based on studies demonstrating the role of the cavotricuspid isthmus. With a high rate of success and minimal complications, catheter ablation is the therapy of choice for patients with the common type of atrial flutter. Left atrial flutter, non-cavotricuspid isthmus dependent, and those associated with heart disease have a worst outcome with catheter ablation. Radiofrequency catheter ablation has also emerged as a curative therapy for paroxysmal atrial fibrillation based on studies demonstrating the role of triggering foci in the pulmonary veins for the initiation of atrial fibrillation. Catheter ablation is performed by a transseptal approach using radiofrequency energy at the ostium of each pulmonary vein. Mapping is guided by special catheters. Sequential radiofrequency applications eliminates or dissociates pulmonary vein muscle activity. Although complications exists, this is the only curative method for these patients. PMID:12966653

  5. Relation of interleukin-6, C-reactive protein, and the prothrombotic state to transesophageal echocardiographic findings in atrial fibrillation.

    PubMed

    Conway, Dwayne S G; Buggins, Peter; Hughes, Elizabeth; Lip, Gregory Y H

    2004-06-01

    Atrial fibrillation (AF) is a major cause of morbidity and mortality from stroke due to thromboembolism from the fibrillating left atrium, including its appendage. We hypothesized that indexes of inflammation (as indicated by C-reactive protein and interleukin-6) and indexes of the prothrombotic state in AF that represent platelet activation (soluble P-selectin levels), endothelial damage or dysfunction (von Willebrand factor), coagulation (tissue factor and fibrinogen), and hemorrheology (plasma viscosity and hematocrit) would be related to the presence of thromboembolic predictors on transesophageal echocardiography in patients with long-term AF. To test this hypothesis, we recruited 37 patients with long-term AF who were receiving warfarin therapy with an international normalized ratio of > or =2.0 for > or =3 weeks before transesophageal echocardiography. Twenty-two patients had dense spontaneous echo contrast (SEC) visible in the left atrium or left atrial appendage, 10 had complex atheromatous plaque in the descending aorta, 11 had peak left atrial appendage velocities < or =0.2 m/s, and 3 had thrombus visible in the left atrial appendage. Twenty-eight patients had > or =1 transesophageal echocardiographic (TEE) risk factor for thromboembolism. Plasma levels of C-reactive protein (p = 0.03) and soluble P-selectin (p = 0.04) and hematocrit (p = 0.004) were higher among patients with AF with dense SEC than among those without. No significant associations were found for other TEE risk factors. Hematocrit was the only variable significantly associated with the presence of > or =1 TEE risk factor among patients with AF (p = 0.007) and the only independent associate of dense SEC after multivariate analysis (relative risk 1.4, 95% confidence interval 1.1 to 1.6) per 1% increase in hematocrit (p = 0.003, r(2) = 0.22). Although hematocrit was the only independent associate of dense SEC and > or =1 TEE risk factor, significant associations between dense SEC and the 2

  6. Torsion of Fatty Appendage of Falciform Ligament: Acute Abdomen in a Child.

    PubMed

    Maccallum, Caroline; Eaton, Sarah; Chubb, Daniel; Franzi, Stephen

    2015-01-01

    Torsion of the fatty appendage of the falciform ligament is an extremely rare condition that leads to severe abdominal pain and raised inflammatory markers. It can be recognised on ultrasound or CT scan. The pathophysiology is the same as that involved in the more common torsion and/or infarction of the greater omentum or epiploic appendages. The condition is best managed conservatively with anti-inflammatory analgesia, and the early recognition of this type of torsion may prevent unnecessary operative intervention to look for a source of abdominal pain. There have been five reported adult cases of a torted fatty appendage of the falciform ligament identified on ultrasound and CT scan, but no paediatric cases. We report a case of torsion of the fatty appendage of the falciform ligament in a ten-year-old boy and describe its imaging characteristics on CT scan. PMID:26664796

  7. Torsion of Fatty Appendage of Falciform Ligament: Acute Abdomen in a Child

    PubMed Central

    Maccallum, Caroline; Eaton, Sarah; Chubb, Daniel; Franzi, Stephen

    2015-01-01

    Torsion of the fatty appendage of the falciform ligament is an extremely rare condition that leads to severe abdominal pain and raised inflammatory markers. It can be recognised on ultrasound or CT scan. The pathophysiology is the same as that involved in the more common torsion and/or infarction of the greater omentum or epiploic appendages. The condition is best managed conservatively with anti-inflammatory analgesia, and the early recognition of this type of torsion may prevent unnecessary operative intervention to look for a source of abdominal pain. There have been five reported adult cases of a torted fatty appendage of the falciform ligament identified on ultrasound and CT scan, but no paediatric cases. We report a case of torsion of the fatty appendage of the falciform ligament in a ten-year-old boy and describe its imaging characteristics on CT scan. PMID:26664796

  8. Attitude stability of a spinning spacecraft during appendage deployment/retraction

    NASA Technical Reports Server (NTRS)

    Fitz-Coy, Norman; Fullerton, Wayne

    1994-01-01

    The work presented is motivated by the need for a national satellite rescue policy, not the ad hoc policy now in place. In studying different approaches for a national policy, the issue of capture and stabilization of a tumbling spacecraft must be addressed. For a rescue mission involving a tumbling spacecraft, it may be advantageous to have a rescue vehicle which is compact and 'rigid' during the rendezvous/capture phase. After capture, passive stabilization techniques could be utilized as an efficient means of detumbling the resulting system (i.e., both the rescue vehicle and captures spacecraft). Since the rescue vehicle is initially compact and 'rigid,' significant passive stabilization through energy dissipation can only be achieved through the deployment of flexible appendages. Once stabilization is accomplished, retraction of the appendages before maneuvering the system to its final destination may also prove advantageous. It is therefore of paramount interest that we study the effect of appendage deployment/retraction on the attitude stability of a spacecraft. Particular interest should be paid to appendage retraction, since if this process is destabilizing, passive stabilization as proposed may not be useful. Over the past three decades, it has been an 'on-again-off-again affair' with the problem of spacecraft appendage deployment. In most instances, these studies have been numerical simulations of specific spacecraft configurations for which there were specific concerns. The primary focus of these studies was the behavior of the appendage during deployment; the effects of appendage retraction was considered only in one of these studies. What is missing in the literature is a thorough study of the effects of appendage deployment/retraction on the attitude stability of a spacecraft. This paper presents a rigorous analysis of the stability of a spinning spacecraft during the deployment or the retraction of an appendage. The analysis is simplified such that

  9. Sinus Node and Atrial Arrhythmias.

    PubMed

    John, Roy M; Kumar, Saurabh

    2016-05-10

    Although sinus node dysfunction (SND) and atrial arrhythmias frequently coexist and interact, the putative mechanism linking the 2 remain unclear. Although SND is accompanied by atrial myocardial structural changes in the right atrium, atrial fibrillation (AF) is a disease of variable interactions between left atrial triggers and substrate most commonly of left atrial origin. Significant advances have been made in our understanding of the genetic and pathophysiologic mechanism underlying the development and progression of SND and AF. Although some patients manifest SND as a result of electric remodeling induced by periods of AF, others develop progressive atrial structural remodeling that gives rise to both conditions together. The treatment strategy will thus vary according to the predominant disease phenotype. Although catheter ablation will benefit patients with predominantly AF and secondary SND, cardiac pacing may be the mainstay of therapy for patients with predominant fibrotic atrial cardiomyopathy. This contemporary review summarizes current knowledge on sinus node pathophysiology with the broader goal of yielding insights into the complex relationship between sinus node disease and atrial arrhythmias. PMID:27166347

  10. 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. PMID:26414617

  11. 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

  12. 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.

  13. [Anticoagulation in atrial fibrillation].

    PubMed

    Schwarz, M; Bode, Ch

    2008-10-01

    In this overview the actual guideline-recommendations for anticoagulation in atrial fibrillation and the problems of the currently available therapy are discussed. Furthermore an outlook over future developments in this field is given. Effective anticoagulation can prohibit thrombembolic events and is thus essential for the prognosis of patients suffering from atrial fibrillation. Until now vitamin-K-antagonists (VKAs) and acetylsalicylic acid (ASA) are available for oral anticoagulation in these patients. VKAs demonstrate a satisfying efficiency combined with rather high bleeding hazard. ASA on the other hand allows only moderate risk reduction with minimal side effects. Thus the guidelines recommend anticoagulation tailored to the individual risk, which can be evaluated by the CHADS2-Score. New therapeutic strategies, like the factor Xa inhibitor rivaroxaban or the factor II inhibitor dabigatran, are actually evaluated in phase III studies. These drugs bear the hope of higher efficiency combined with improved safety and much more comfortable use in the daily practice (e. g. no need for INR measurement, no dose adaptation). PMID:18836647

  14. 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. PMID:21708143

  15. Fiber photo-catheters with spatially modulated diffusers for laser treatment of atrial fibrillation

    NASA Astrophysics Data System (ADS)

    Peshko, Igor; Rubtsov, Vladimir

    2007-02-01

    A new generation of the optical fiber catheter has been developed for surgical treatment of atrial fibrillation with laser radiation. Atrial fibrillation (AF) is a heart rhythm abnormality that involves irregular and rapid heartbeats. The surgical maze procedure was the first treatment that offered a permanent solution for maintaining a normal sinus rhythm in patients with AF. This procedure involves the creation of a maze-like series of incisions in the left atrium, resulting in isolation of the pulmonary vein and removal of the left atrial appendage. To produce long continuous transmural lesions laser diodes operating in near IR range along with end-emitting fiber catheters have been used experimentally. The absence of side-emitting flexible catheters with the ability to produce long continuous lesions limits the further development of this technology. In this research, a new type of an optical catheter consisting of a flexible, spatially modulated fiber diffuser has been used to make continuous photocoagulation lesions for effective maze procedure treatments.

  16. Expression of hyperpolarization-activated cyclic nucleotide-gated channel isoforms in a canine model of atrial fibrillation

    PubMed Central

    HE, WEI; ZHANG, JIAN; GAN, TIANYI; XU, GUOJUN; TANG, BAOPENG

    2016-01-01

    The aim of the present study was to analyze the mRNA and protein expression levels of atrial hyperpolarization-activated cyclic nucleotide-gated (HCN) channel isoforms in the left atrial muscle of dogs with multiple organ failure. A total of 14 beagle dogs with multiple organ failure, including seven cases with sinus rhythm and seven cases with atrial fibrillation (AF), underwent surgery to remove a sample of left atrial appendage tissue. The expression levels of a number of HCN channel subtypes were subsequently measured using quantitative polymerase chain reaction and western blot analysis. The mRNA and protein expression levels of HCN2 and HCN4 increased significantly in the AF group when compared with the sinus rhythm group. However, expression of the HCN1 isoform was not detected. Therefore, increased expression levels of HCN2 and HCN4 may be important molecular mechanisms in the pathogenesis of AF, which were associated with differences in patients with valvular heart disease. PMID:27347074

  17. 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.

  18. Sonic hedgehog signaling pathway in vertebrate epithelial appendage morphogenesis: perspectives in development and evolution.

    PubMed

    Chuong, C M; Patel, N; Lin, J; Jung, H S; Widelitz, R B

    2000-11-01

    Vertebrate epithelial appendages are elaborate topological transformations of flat epithelia into complex organs that either protrude out of external (integument) and internal (oral cavity, gut) epithelia, or invaginate into the surrounding mesenchyme. Although they have specific structures and diverse functions, most epithelial appendages share similar developmental stages, including induction, morphogenesis, differentiation and cycling. The roles of the SHH pathway are analyzed in exemplary organs including feather, hair, tooth, tongue papilla, lung and foregut. SHH is not essential for induction and differentiation, but is involved heavily in morphogenetic processes including cell proliferation (size regulation), branching morphogenesis, mesenchymal condensation, fate determination (segmentation), polarizing activities and so on. Through differential activation of these processes by SHH in a spatiotemporal-specific fashion, organs of different shape and size are laid down. During evolution, new links of developmental pathways may occur and novel forms of epithelial appendages may emerge, upon which evolutionary selections can act. Sites of major variations have progressed from the body plan to the limb plan to the epithelial appendage plan. With its powerful morphogenetic activities, the SHH pathway would likely continue to play a major role in the evolution of novel epithelial appendages. PMID:11130174

  19. [Vectorcardiographic manifestations of atrial enlargements].

    PubMed

    de Micheli, A; Medrano, G A

    1990-01-01

    Rational interpretation of changes of the P loop due to atrial enlargements must to rely on the magnitude and spatial orientation of main resultant vectors of the activation sequence of the atria. Under normal conditions, these vectors give rise to a mean vector oriented to the left downward and discretely forward with respect to their point of origin. In the presence of right atrial enlargement, the manifestation of the first vector of atrial depolarization, oriented downward and forward, is increased. This one moves in the same direction as the mean vector of atrial depolarization, originating an elongated P loop of more than 100 mcv in the three planes. Nevertheless, in the horizontal plane, increase of the P loop voltage predominates when hypertrophy exists, while augmentation of its area predominates when dilatation exists. In left atrial enlargement, the manifestation of the second vector of atrial depolarization, oriented to the left and backward, is augmented, and it moves in the same direction as the mean vector of atrial depolarization. For this, the PF loop acquires a characteristic aspect of a boxing glove, an the PH loop becomes diphasic, with its posterior area more or less prominent, or with a typical figure-eight conformation. If a biatrial enlargement is present, the manifestation of both the main resultant vectors of atrial depolarization is accentuated. Therefore the voltage of the diphasic P loop increases. Moreover the Ps loop has a triangular configuration, with its base of 30 msc or more, located below its point of origin. Generally disturbances of interatrial and intraatrial conduction coexist owing to myocardial damage. PMID:2146934

  20. Genomics of Atrial Fibrillation.

    PubMed

    Gutierrez, Alejandra; Chung, Mina K

    2016-06-01

    Atrial fibrillation (AF) is a common clinical arrhythmia that appears to be highly heritable, despite representing a complex interplay of several disease processes that generally do not manifest until later in life. In this manuscript, we will review the genetic basis of this complex trait established through studies of familial AF, linkage and candidate gene studies of common AF, genome wide association studies (GWAS) of common AF, and transcriptomic studies of AF. Since AF is associated with a five-fold increase in the risk of stroke, we also review the intersection of common genetic factors associated with both of these conditions. Similarly, we highlight the intersection of common genetic markers associated with some risk factors for AF, such as hypertension and obesity, and AF. Lastly, we describe a paradigm where genetic factors predispose to the risk of AF, but which may require additional stress and trigger factors in older age to allow for the clinical manifestation of AF. PMID:27139902

  1. Efficacy of a novel bipolar radiofrequency ablation device on the beating heart for atrial fibrillation ablation: A chronic porcine study

    PubMed Central

    Voeller, Rochus K.; Zierer, Andreas; Lall, Shelly C.; Sakamoto, Shun-ichiro; Schuessler, Richard B.; Damiano, Ralph J.

    2015-01-01

    Background Over the recent years, a variety of energy sources have been used to replace the traditional incisions of the Cox-Maze procedure for the surgical treatment of atrial fibrillation. This study evaluated the safety and efficacy of a new bipolar radiofrequency ablation device for atrial ablation in a chronic porcine model. Methods Six pigs underwent a Cox-Maze IV procedure on a beating heart off cardiopulmonary bypass using the Atricure Isolator II™ bipolar ablation device. In addition, 6 pigs underwent median sternotomy and pericardiotomy alone to serve as a control group. All animals were survived for 30 days. Each pig underwent induction of atrial fibrillation, and was then sacrificed to remove the heart en bloc for histological assessment. MRI scan were also obtained preoperatively and postoperatively to assess atrial and ventricular function, pulmonary vein anatomy, valve function, and coronary artery patency. Results All animals survived the operation. Electrical isolation of the left atrial appendage and the pulmonary veins was documented by pacing acutely and at 30 days in all animals. No animal that underwent the Cox-Maze IV procedure was able to be induced into atrial fibrillation at 30 days postoperatively, compared to all the sham animals. All 257 ablations examined were discrete, linear and transmural, with a mean lesion width of 2.2±1.1 mm and a mean lesion depth of 5.3±3.0 mm. Conclusions The Atricure Isolator II™ was able to create reliable chronic transmural lesions of the modified Cox-Maze procedure on a beating heart without cardiopulmonary bypass 100% of the time. There were no discernible effects on ventricular or valvular function. PMID:20122702

  2. 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. PMID:27560278

  3. Rate control in atrial fibrillation.

    PubMed

    Van Gelder, Isabelle C; Rienstra, Michiel; Crijns, Harry J G M; Olshansky, Brian

    2016-08-20

    Control of the heart rate (rate control) is central to atrial fibrillation management, even for patients who ultimately require control of the rhythm. We review heart rate control in patients with atrial fibrillation, including the rationale for the intervention, patient selection, and the treatments available. The choice of rate control depends on the symptoms and clinical characteristics of the patient, but for all patients with atrial fibrillation, rate control is part of the management. Choice of drugs is patient-dependent. β blockers, alone or in combination with digoxin, or non-dihydropyridine calcium-channel blockers (not in heart failure) effectively lower the heart rate. Digoxin is least effective, but a reasonable choice for physically inactive patients aged 80 years or older, in whom other treatments are ineffective or are contraindicated, and as an additional drug to other rate-controlling drugs, especially in heart failure when instituted cautiously. Atrioventricular node ablation with pacemaker insertion for rate control should be used as an approach of last resort but is also an option early in the management of patients with atrial fibrillation treated with cardiac resynchronisation therapy. However, catheter ablation of atrial fibrillation should be considered before atrioventricular node ablation. Although rate control is a top priority and one of the first management issues for all patients with atrial fibrillation, many issues remain. PMID:27560277

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

    PubMed

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

    1995-11-01

    Radiofrequency ablation has gained acceptance in the treatment of patients with symptomatic Wolff-Parkinson-White syndrome. The purpose of this study was to characterize the relation between temperature and other electroconductive parameters in patients undergoing atrial insertion accessory pathway ablation utilizing a thermistor equipped catheter. The mean temperature and power at sites of atrial insertion ablation are lower than has been previously associated with creation of radiofrequency lesions in the ventricle. While high cavitary blood flow in the atrium may result in cooling, the thinner atrial tissue may require less energy to achieve adequate heating than ventricular myocardium. PMID:8552513

  5. Atrial Remodeling and Atrial Tachyarrhythmias in Arrhythmogenic Right Ventricular Cardiomyopathy.

    PubMed

    Wu, Lingmin; Guo, Jinrui; Zheng, Lihui; Chen, Gang; Ding, Ligang; Qiao, Yu; Sun, Wei; Yao, Yan; Zhang, Shu

    2016-09-01

    Less is known about atrial remodeling and atrial tachyarrhythmias (ATa) in arrhythmogenic right ventricular cardiomyopathy (ARVC); this cross-sectional study aimed to determine the prevalence, characterization, and predictors of atrial remodeling and ATa in a large series of patients with ARVC. From February 2004 to September 2014, 294 consecutive patients who met the task force criteria for ARVC were enrolled. The prevalence, characterization, and predictors of atrial dilation and ATa were investigated. Right atrium (RA) dilation was identified in 160 patients (54.4%) and left atrium dilation in 66 patients (22.4%). Both RA and left atrium dilation were found in 44 patients (15.0%). Twenty-five patients (8.5%) had atrial fibrillation (AF), whereas 19 patients (6.5%) had atrial flutter (AFL). Of which, 7 patients (2.4%) had both AF and AFL. Multivariate analysis showed that AFL (odds ratio [OR] 10.309; 95% confidence interval [CI] 2.770 to 38.462; p <0.001), hypertension (OR 9.174; 95% CI 2.364 to 35.714; p = 0.001), and RA dilation (OR 6.993; 95% CI 1.623 to 30.303; p = 0.009) were associated with increased risk for AF. AF (OR 10.526; 95% CI 2.786 to 40.000; p = 0.001) increased the risk of AFL. In conclusion, atrial remodeling and ATa were common in patients with ARVC. PMID:27378141

  6. 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.

  7. 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. PMID:19021742

  8. Who Is at Risk for Atrial Fibrillation?

    MedlinePlus

    ... from the NHLBI on Twitter. Who Is at Risk for Atrial Fibrillation? Atrial fibrillation (AF) affects millions ... than 75. AF is uncommon in children. Major Risk Factors AF is more common in people who ...

  9. Genetics Home Reference: familial atrial fibrillation

    MedlinePlus

    ... fibrillation also increases the risk of stroke and sudden death. Complications of familial atrial fibrillation can occur at ... beats , increasing the risk of syncope, stroke, and sudden death. Most cases of atrial fibrillation are not caused ...

  10. [Right Atrial Rupture due to Blunt Trauma;Report of a Case].

    PubMed

    Nishi, Toshihiko; Tamenishi, Akinori; Niimi, Takao; Okamoto, Hiroshi

    2015-07-01

    The survival rate of cardiac rupture due to blunt trauma is generally low. We report a case of surgical treatment of blunt cardiac trauma. A 55-year-old man was admitted to our hospital for blunt trauma due to a car accident. His hemodynamics was compromised due to cardiac tamponade. The patient underwent pericardial drainage by small subxiphoid incision. Although about 400 ml of blood was evacuated, hemorrhage was still continuing. After full sternotomy, we found a 3 mm tear in the right atrial appendage and sutured it easily without cardiopulmonary bypass. The patient recovered uneventfully and was discharged on the 10th postoperative day. He is now leading a normal life. PMID:26197827

  11. Obstructive sleep apnea in atrial fibrillation patients.

    PubMed

    Arias, Miguel A; Alonso-Fernández, Alberto; García-Río, Francisco; Sánchez, Ana; López, Juana M; Pagola, Carlos

    2006-06-28

    A high prevalence of obstructive sleep apnea has been demonstrated in patients with atrial fibrillation. Our comments want to emphasize the importance of identifying and treating a large proportion of patients with atrial fibrillation who have undiagnosed obstructive sleep apnea as an additional preventive strategy for atrial fibrillation patients. PMID:16309764

  12. [Non-invasive evaluation of the hemodynamic profile in patients with heart failure: estimation of right atrial pressure].

    PubMed

    Temporelli, P L; Scapellato, F; Giannuzzi, P

    2000-10-01

    The estimation of right atrial pressure is often needed for the diagnosis, management and monitoring of various pathologic hemodynamic conditions and plays a significant role in patients with chronic heart failure. In the past decade several attempts have been made to non-invasively estimate right atrial pressure, and echocardiography has always been considered the most reliable tool. Morphologic parameters such as respiratory motion of the inferior vena cava, its respiratory diameters and percent collapse (caval index), left hepatic vein diameter or right atrial dimension (areas, volumes) were initially studied. More recently, functional data such as left hepatic or tricuspid flow variables have been considered. Some of these indexes, however, offer only semiquantitative measures of right atrial pressure, and have failed to demonstrate any prognostic value. Others, although highly sensitive and specific, are useful only in selected groups of patients because of technical or clinical limitations. In recent years, attention has focused on Doppler diastolic tricuspid flow as a means of predicting mean right atrial pressure. Analyzing the Doppler tricuspid velocity profile and mean right atrial pressure (Swan-Ganz catheter) simultaneously recorded in patients with severe left ventricular systolic dysfunction and chronic heart failure, acceleration rate of early filling emerged as the strongest independent predictor of right atrial pressure both in patients in sinus rhythm and in those with atrial fibrillation (r = 0.98), irrespective of whether the recordings are at baseline or after acute loading manipulations. PMID:11068714

  13. Doppler-derived acceleration rate of right ventricular early filling as a measurement of right atrial pressure in chronic heart failure secondary to ischemic or idiopathic dilated cardiomyopathy.

    PubMed

    Scapellato, F; Eleuteri, E; Temporelli, P L; Imparato, A; Corrà, U; Giannuzzi, P

    1998-02-15

    This study demonstrates that a Doppler-derived tricuspid flow velocity pattern provides an accurate, feasible, and noninvasive method of estimating and monitoring mean right atrial pressure in patients with heart failure due to left ventricular systolic dysfunction, and who are both in sinus rhythm and atrial fibrillation. In particular, the acceleration rate of early right ventricular filling is a powerful and independent predictor of mean right atrial pressure. PMID:9485149

  14. Atriocaval Rupture After Right Atrial Isthmus Ablation for Atrial Flutter.

    PubMed

    Vloka, Caroline; Nelson, Daniel W; Wetherbee, Jule

    2016-06-01

    A patient with symptomatic typical atrial flutter (AFL) underwent right atrial isthmus ablation with an 8-mm catheter. Eight months later, his typical AFL recurred. Ten months later, he underwent a repeat right atrial isthmus ablation with an irrigated tip catheter and an 8-mm tip catheter. Six weeks after his second procedure, while performing intense sprint intervals on a treadmill, he developed an abrupt onset of chest pain, hypotension, and cardiac tamponade. He underwent emergency surgery to repair an atriocaval rupture and has done well since. Our report suggests that an association of multiple radiofrequency ablations with increased risk for delayed atriocaval rupture occurring 1 to 3 months after ablation. In conclusion, although patients generally were advised to limit exercise for 1 to 2 weeks after AFL ablation procedures in the past, it may be prudent to avoid intense exercise for at least 3 months after procedure. PMID:27112285

  15. Computational Shape Models Characterize Shape Change of the Left Atrium in Atrial Fibrillation

    PubMed Central

    Cates, Joshua; Bieging, Erik; Morris, Alan; Gardner, Gregory; Akoum, Nazem; Kholmovski, Eugene; Marrouche, Nassir; McGann, Christopher; MacLeod, Rob S.

    2014-01-01

    Shape change of the left atrium (LA) and LA appendage in atrial fibrillation (AF) patients is hypothesized to be linked to AF pathology and to play a role in thrombogenesis; however, many aspects of shape variation in the heart are poorly understood. To date, studies of the LA shape in AF have been limited to empirical observation and summary metrics, such as volume and its likeness to a sphere. This paper describes a more comprehensive approach to the study of the LA shape through the use of computationally derived statistical shape models. We describe practical approaches that we have developed to extract shape parameters automatically from the three-dimensional MR images of the patient. From these images and our techniques, we can produce a more comprehensive description of LA geometric variability than that has been previously possible. We present the methodology and results from two examples of specific analyses using shape models: (1) we describe statistically significant group differences between the normal control and AF patient populations (n = 137) and (2) we describe characteristic shapes of the LA appendage that are associated with the risk of thrombogenesis determined by transesophageal echocardiography (n = 203). PMID:26380559

  16. Incidence and predictive factors of atrial fibrillation after ablation of typical atrial flutter.

    PubMed

    Laurent, Valérie; Fauchier, Laurent; Pierre, Bertrand; Grimard, Caroline; Babuty, Dominique

    2009-03-01

    Although cavotricuspid isthmus radiofrequency catheter ablation is considered curative therapy for typical atrial flutter, many patients develop an atrial fibrillation after ablation. The purpose of our study was to determine the incidence and the predictive factors of post-ablation atrial fibrillation. One hundred and forty eight consecutive patients underwent cavotricuspid isthmus ablation for the treatment of typical atrial flutter between January 2004 and December 2005 in our electrophysiological department. Complete cavotricuspid isthmus block was successfully obtained in 96.6% of the patients. At the end of the electrophysiological study a sustained atrial fibrillation was inducible in 20 patients (13.5%). During an average follow-up of 21.3 +/- 8.2 months, atrial fibrillation occurred in 27% of the patients. Univariate analysis identified four parameters correlated with post-ablation atrial fibrillation among the 21 parameters tested: the young age of the patients, a prior history of atrial fibrillation, an inducible atrial fibrillation, and a paroxysmal atrial flutter. Only inducible atrial fibrillation and paroxysmal atrial flutter were independent factors linked to atrial fibrillation after ablation. In our study the incidence of atrial fibrillation after cavotricuspid isthmus radiofrequency catheter ablation is 152 per 1,000 patient-years, i.e. 25 times higher than the incidence of atrial fibrillation in the general population of the same age. Twenty five percent of the patients who had neither prior history of atrial fibrillation nor structural heart disease suffered from atrial fibrillation during a mean follow-up of 21.3 +/- 8.2 months. All these results suggest that atrial flutter and fibrillation could be manifestations of a more general electrophysiologic disease. They emphasize the need for all these patients to benefit from regular, long-term cardiological follow-up after cavotricuspid isthmus ablation because of the high incidence of atrial

  17. Totally thorascopic surgical ablation of persistent AF and long-standing persistent atrial fibrillation using the "Dallas" lesion set.

    PubMed

    Edgerton, James R; Jackman, Warren M; Mahoney, Cecile; Mack, Michael J

    2009-12-01

    Minimally invasive surgery consisting of bipolar radiofrequency pulmonary vein (PV) isolation and limited ganglionated plexus ablation is effective in eliminating atrial fibrillation (AF) in patients with paroxysmal AF but is less effective in those with persistent AF or long-standing persistent AF. The purpose of this study was examine the results of minimally invasive surgery incorporating an additional set of radiofrequency ablation lines replicating a left-sided Cox maze III procedure. Thirty patients with persistent AF (n = 10) or long-standing persistent AF (n = 20) underwent minimally invasive surgery with an extended lesion set and PV isolation for a minimum follow-up of 6 months. Linear lesions were created at the roof line, at the anterior line, and between the roof line and the left atrial appendage. All patients underwent limited ganglionated plexus ablation and left atrial appendage excision as well as PV isolation verification. Block across the roof and anterior lines was confirmed in 29 (96.6%) of the 30 patients. Follow-up included 2-week event monitoring with auto-trigger in 21 patients, pacemaker interrogation in 8, and ECG in 1 who was in AF and refused longer-term monitoring. No operative mortality or major morbidity occurred. At 6 months, 24 (80%) of the 30 patients were free of AF: 15 (75%) with long-standing persistent AF and 9 (90%) with persistent AF. Among the six failures, burden of AF was low: one had 1 episode >15 seconds, two had 4 episodes, one had 6 episodes, one had >50 episodes, and one had AF on ECG and refused further monitoring. Early results of minimally invasive surgery with a new extended linear lesion set suggest increased efficacy over PV isolation and limited ganglionated plexus ablation in patients with persistent AF or long-standing persistent AF. PMID:19959146

  18. Cell proliferation dynamics in regeneration of the operculum head appendage in the annelid Pomatoceros lamarckii.

    PubMed

    Szabó, Réka; Ferrier, David Ellard Keith

    2014-07-01

    Regeneration of lost or damaged appendages is a widespread and ecologically important ability in the animal kingdom, and also of great significance to developing regenerative medicine. The operculum of serpulid polychaetes is one among the many diverse appendages found in the lophotrochozoan superphylum, a clade hitherto understudied with respect to the mechanisms of appendage regeneration. In this study, we establish the normal time course of opercular regeneration in the serpulid Pomatoceros lamarckii and describe cell proliferation patterns in the regenerating opercular filament. The P. lamarckii operculum regenerates through a rapid and consistent series of morphogenetic events. Based on 5-bromo-2'-deoxyuridine (BrdU) labeling and anti-phosphohistone H3 immunohistochemistry, opercular regeneration appears to be a mixture of an early morphallactic stage, and a later phase characterized by widespread proliferative activity within the opercular filament. Tracking residual pigmentation suggests that the distal part of the stump gives rise to the most distal structures of the operculum via morphallactic remodeling, whereas more proximal structures are derived from the proximal stump. Our work underscores the diversity of regenerative strategies employed by animals and introduces P. lamarckii as an emerging model of appendage regeneration. PMID:24799350

  19. Kif3a interacts with Dynactin subunit p150 Glued to organize centriole subdistal appendages.

    PubMed

    Kodani, Andrew; Salomé Sirerol-Piquer, Maria; Seol, Allen; Garcia-Verdugo, Jose Manuel; Reiter, Jeremy F

    2013-02-20

    Formation of cilia, microtubule-based structures that function in propulsion and sensation, requires Kif3a, a subunit of Kinesin II essential for intraflagellar transport (IFT). We have found that, Kif3a is also required to organize centrioles. In the absence of Kif3a, the subdistal appendages of centrioles are disorganized and lack p150(Glued) and Ninein. Consequently, microtubule anchoring, centriole cohesion and basal foot formation are abrogated by loss of Kif3a. Kif3a localizes to the mother centriole and interacts with the Dynactin subunit p150(Glued). Depletion of p150(Glued) phenocopies the effects of loss of Kif3a, indicating that Kif3a recruitment of p150(Glued) is critical for subdistal appendage formation. The transport functions of Kif3a are dispensable for subdistal appendage organization as mutant forms of Kif3a lacking motor activity or the motor domain can restore p150(Glued) localization. Comparison to cells lacking Ift88 reveals that the centriolar functions of Kif3a are independent of IFT. Thus, in addition to its ciliogenic roles, Kif3a recruits p150(Glued) to the subdistal appendages of mother centrioles, critical for centrosomes to function as microtubule-organizing centres. PMID:23386061

  20. Role of homeobox genes in the patterning, specification and differentiation of ectodermal appendages in mammals

    PubMed Central

    Duverger, Olivier; Morasso, Maria I.

    2008-01-01

    Homeobox genes are an evolutionarily conserved class of transcription factors that are key regulators during developmental processes such as regional specification, patterning and differentiation. In this review, we summarize the expression pattern, loss-and/or gain-of-function mouse models, and naturally occurring mouse and human mutations of known homeobox genes required for the development of ectodermal appendages. PMID:18459147

  1. Study of the dynamics of orbital assemblies including interactions with geometrical appendages

    NASA Technical Reports Server (NTRS)

    Hull, G.; Ness, D. J.

    1972-01-01

    Computer programs are provided for the simulation of a unified flexible spacecraft relative to the dynamics of orbital assemblies, including interactions with geometrical appendages. The CDC 6500 and Univac 1108 computers are used with FORTRAN. The software and hardware requirements are described and diagrammed, as well as the overall deck set-up. A list of standard and nonstandard routines is also included.

  2. Role of homeobox genes in the patterning, specification, and differentiation of ectodermal appendages in mammals.

    PubMed

    Duverger, Olivier; Morasso, Maria I

    2008-08-01

    Homeobox genes are an evolutionarily conserved class of transcription factors that are key regulators during developmental processes such as regional specification, patterning, and differentiation. In this review, we summarize the expression pattern, loss- and/or gain-of-function mouse models, and naturally occurring mouse and human mutations of known homeobox genes required for the development of ectodermal appendages. PMID:18459147

  3. Cryoballoon Ablation for Atrial Fibrillation

    PubMed Central

    Andrade, Jason G; Dubuc, Marc; Guerra, Peter G; Macle, Laurent; Rivard, Lena; Roy, Denis; Talajic, Mario; Thibault, Bernard; Khairy, Paul

    2012-01-01

    Focal point-by-point radiofrequency catheter ablation has shown considerable success in the treatment of paroxysmal atrial fibrillation. However, it is not without limitations. Recent clinical and preclinical studies have demonstrated that cryothermal ablation using a balloon catheter (Artic Front©, Medtronic CryoCath LP) provides an effective alternative strategy to treating atrial fibrillation. The objective of this article is to review efficacy and safety data surrounding cryoballoon ablation for paroxysmal and persistent atrial fibrillation. In addition, a practical step-by-step approach to cryoballoon ablation is presented, while highlighting relevant literature regarding: 1) the rationale for adjunctive imaging, 2) selection of an appropriate cryoballoon size, 3) predictors of efficacy, 4) advanced trouble-shooting techniques, and 5) strategies to reduce procedural complications, such as phrenic nerve palsy. PMID:22557842

  4. A review of atrial fibrillation.

    PubMed Central

    Dang, David; Arimie, Raluca; Haywood, L. Julian

    2002-01-01

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and accounts for more physician visits and hospital days than any other cardiac rhythm disturbance. Atrial filbrillation is incresing in frequency as the population ages, and therefore, a knowledge of the clinical spectrum and available treatment regimen is essential. Here, we review the pathophysiology, clinical presentation, and current status of management. Experience is being rapidly accumulated in all of the areas discussed in the management of this important clinical entity. Images Figure 1 Figure 2 PMID:12510703

  5. Fibrinolytic function and atrial fibrillation.

    PubMed

    Marín, Francisco; Roldán, Vanessa; Lip, Gregory Y H

    2003-03-15

    Atrial fibrillation (AF) is the commonest sustained cardiac arrhythmia, which is associated with a substantial risk of stroke and thromboembolism. A prothrombotic or hypercoagulable state has been observed in these patients, although previous studies have mainly focused on various clotting factors, endothelial damage or dysfunction markers and platelet activation. However, fibrinolytic function has been less frequently studied, despite the fibrinolytic system playing an important role in preventing intravascular thrombosis. Indeed, increasing evidence suggests that an imbalance between the fibrinolytic function is of great importance in cardiovascular disease. This review will begin by providing a brief approach to fibrinolytic function and examine previous studies about fibrinolytic activity and atrial fibrillation. PMID:12818244

  6. [Atrial fibrillation and physical activity].

    PubMed

    Apor, Péter

    2013-03-31

    Atrial fibrillation is the most frequent arrhythmia. Its "lone" form (when underlying pathology is not discovered) can be detected in a small percentage of endurance sports participants, and in growing numbers among veterans, probably as a result of some cardiac or other irregularities. Enhanced vagal tone and sudden sympathetic impulse, repetitive oxidative stress, inflammatory processes, enlarged atria, electric instabilization can explain the higher occurrence. Treatment of atrial fibrillation enables the affected persons to participate in regular medium-intensity exercise, 3-5 hours a week, which offers a protective role against cardiovascular, metabolic and mental illnesses. PMID:23524234

  7. CT findings of atrial myxoma

    SciTech Connect

    Tsuchiya, F.; Kohno, A.; Saitoh, R.; Shigeta, A.

    1984-04-01

    The computed tomographic (CT) appearance of six atrial myxomas was analyzed. Five of the myxomas were located in the left atrium and one was in the right atrium. The margin of the myxoma was at least slightly lobulated in five cases and the content was inhomogeneous in all. Calcification was demonstrated in three cases. The site of attachment of the myxoma was demonstrated by CT to be the arial septum in all cases. The CT finding correlated well with the operative findings. It is concluded that it is possible with CT to diagnose atrial myxoma by the location and nature of the intracardiac mass and to differentiate it from thrombus.

  8. Atrial Fibrillation in Ten Cows

    PubMed Central

    Brightling, P.; Townsend, H. G. G.

    1983-01-01

    An irregular cardiac rhythm was identified in ten adult cows during auscultation of the heart and was subsequently characterized as atrial fibrillation by electrocardiography. The occurrence of the arrhythmia was associated with primary, organic disease of the heart in two animals which had valvular endocarditis. In seven of the other cows secondary or “functional” atrial fibrillation occurred in association with disorders of abdominal origin, six gastrointestinal disorders and one uterine torsion. Spontaneous conversion to normal sinus rhythm occurred in six cows after elimination of the primary disease. ImagesFigure 1b.Figure 3a.Figure 3b. PMID:17422324

  9. 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

  10. Body appendages fine-tune posture and moments in freely manoeuvring fruit flies.

    PubMed

    Berthé, Ruben; Lehmann, Fritz-Olaf

    2015-10-01

    The precise control of body posture by turning moments is key to elevated locomotor performance in flying animals. Although elevated moments for body stabilization are typically produced by wing aerodynamics, animals also steer using drag on body appendages, shifting their centre of body mass, and changing moments of inertia caused by active alterations in body shape. To estimate the instantaneous contribution of each of these components for posture control in an insect, we three-dimensionally reconstructed body posture and movements of body appendages in freely manoeuvring fruit flies (Drosophila melanogaster) by high-speed video and experimentally scored drag coefficients of legs and body trunk at low Reynolds number. The results show that the sum of leg- and abdomen-induced yaw moments dominates wing-induced moments during 17% of total flight time but is, on average, 7.2-times (roll, 3.4-times) smaller during manoeuvring. Our data reject a previous hypothesis on synergistic moment support, indicating that drag on body appendages and mass-shift inhibit rather than support turning moments produced by the wings. Numerical modelling further shows that hind leg extension alters the moments of inertia around the three main body axes of the animal by not more than 6% during manoeuvring, which is significantly less than previously reported for other insects. In sum, yaw, pitch and roll steering by body appendages probably fine-tune turning behaviour and body posture, without providing a significant advantage for posture stability and moment support. Motion control of appendages might thus be part of the insect's trimming reflexes, which reduce imbalances in moment generation caused by unilateral wing damage and abnormal asymmetries of the flight apparatus. PMID:26347566

  11. The AP-2 Adaptor β2 Appendage Scaffolds Alternate Cargo Endocytosis

    PubMed Central

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

    2008-01-01

    The independently folded appendages of the large α and β2 subunits of the endocytic adaptor protein (AP)-2 complex coordinate proper assembly and operation of endocytic components during clathrin-mediated endocytosis. The β2 subunit appendage contains a common binding site for β-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 β2 subunit expression on the internalization of transferrin is considerably weaker than an AP-2 α subunit knockdown. We show the mild sorting defect is due to fortuitous substitution of the β2 chain with the closely related endogenous β1 subunit of the AP-1 adaptor complex. Simultaneous silencing of both β1 and β2 subunit transcripts recapitulates the strong α subunit RNA interference (RNAi) phenotype and results in loss of ARH from endocytic clathrin coats. An RNAi-insensitive β2-yellow fluorescent protein (YFP) expressed in the β1 + β2-silenced background restores cellular AP-2 levels, robust transferrin internalization, and ARH colocalization with cell surface clathrin. The importance of the β appendage platform subdomain over clathrin for precise deposition of ARH at clathrin assembly zones is revealed by a β2-YFP with a disrupted ARH binding interface, which does not restore ARH colocalization with clathrin. We also show a β-arrestin 1 mutant, which engages coated structures in the absence of any G protein-coupled receptor stimulation, colocalizes with β2-YFP and clathrin even in the absence of an operational clathrin binding sequence. These findings argue against ARH and β-arrestin binding to a site upon the β2 appendage platform that is later obstructed by polymerized clathrin. We conclude that ARH and β-arrestin depend on a privileged β2 appendage site for proper cargo recruitment to clathrin bud sites. PMID:18843039

  12. 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.

  13. Atrial fibrillation alters the microRNA expression profiles of the left atria of patients with mitral stenosis

    PubMed Central

    2014-01-01

    Background Structural changes of the left and right atria associated with atrial fibrillation (AF) in mitral stenosis (MS) patients are well known, and alterations in microRNA (miRNA) expression profiles of the right atria have also been investigated. However, miRNA changes in the left atria still require delineation. This study evaluated alterations in miRNA expression profiles of left atrial tissues from MS patients with AF relative to those with normal sinus rhythm (NSR). Methods Sample tissues from left atrial appendages were obtained from 12 MS patients (6 with AF) during mitral valve replacement surgery. From these tissues, miRNA expression profiles were created and analyzed using a human miRNA microarray. Results were validated via reverse-transcription and quantitative PCR for 5 selected miRNAs. Potential miRNA targets were predicted and their functions and potential pathways analyzed via the miRFocus database. Results The expression levels of 22 miRNAs differed between the AF and NSR groups. Relative to NSR patients, in those with AF the expression levels of 45% (10/22) of these miRNAs were significantly higher, while those of the balance (55%, 12/22) were significantly lower. Potential miRNA targets and molecular pathways were identified. Conclusions AF alters the miRNA expression profiles of the left atria of MS patients. These findings may be useful for the biological understanding of AF in MS patients. PMID:24461008

  14. Management of atrial fibrillation in bradyarrhythmias.

    PubMed

    Boriani, Giuseppe; Padeletti, Luigi

    2015-06-01

    Sinus node disease (SND), a common indication to implant a pacemaker, is frequently associated with atrial fibrillation (AF), either at implantation (paroxysmal AF) or during follow-up, which often evolves to persistent or permanent AF. Pacemakers with an atrial lead allow continuous monitoring of the atrial rhythm and enable detection of the burden of AF. Asymptomatic atrial tachyarrhythmias, being associated with increased risk of stroke, have important prognostic implications, and their detection could guide decision-making about antithrombotic prophylaxis. Pacing mode and pacing algorithms can influence the occurrence of AF and atrial tachyarrhythmias. In DDD/DDDR pacing mode, reduction of unnecessary right ventricular pacing positively affects the occurrence and evolution of AF, but patients with a history of atrial tachyarrhythmias maintain an increased risk of arrhythmic events. In the MINERVA study, the use of algorithms that act in the atrium for preventive pacing and atrial antitachycardia pacing while minimizing right ventricular pacing was beneficial in patients with SND and previous atrial tachyarrhythmias, and was associated with a significant reduction in evolution to permanent AF. New information available on therapies delivered at the atrial level by implanted devices suggests clinical advantages that could improve current guidelines for the management of AF and atrial tachyarrhythmias. PMID:25781413

  15. Early Temporal and Spatial Regularization of Persistent Atrial Fibrillation Predicts Termination and Arrhythmia-Free Outcome

    PubMed Central

    Forclaz, Andrei; Narayan, Sanjiv M.; Scherr, Daniel; Linton, Nick; Jadidi, Amir S.; Nault, Isabelle; Rivard, Lena; Miyazaki, Shinsuke; Linton, Nick; Uldry, Laurent; Wright, Matthew; Shah, Ashok J; Liu, Xingpeng; Xhaet, Olivier; Derval, Nicolas; Knecht, Sébastien; Sacher, Frédéric; Jaïs, Pierre; Hocini, Mélèze; Haïssaguerre, Michel

    2011-01-01

    Background Termination of persistent atrial fibrillation (AF) is a valuable ablation endpoint, but is difficult to anticipate. We evaluated whether temporal and spatial indices of AF regularization predict intra-procedural AF termination and outcome. Objective To test whether temporospatial organization of AF after pulmonary vein isolation (PVI) predicts whether subsequent stepwise ablation will terminate persistent AF or predict outcome. Methods In 75 patients with persistent AF, we measured AF cycle length (AFCL), temporal regularity index (TRI, a spectral measure of timing regularity) and spatial regularity index (SRI, cycle-to-cycle variations in spatial vector) between right atrial appendage, proximal and distal coronary sinus before and during stepwise ablation to the endpoint of AF termination. Results AF termination was achieved in 59 patients (79%) by ablation. AF terminated during PVI in 11 patients, who were excluded from analysis. In the remaining 48 patients, TRI and SRI increased during stepwise ablation, as compared to 16 patients without termination (p < 0.05). AFCL prolonged in both groups. From ROC analysis of the first 22 patients (training set), a post-PVI TRI increase predicted AF termination in the latter 42 patients (test set) with PPV 96 %, NPV 53 %, sensitivity 71 % and specificity 91 %. Results were similar for SRI. After 36 months, higher arrhythmia-free outcome was observed in patients in whom PVI caused temporospatial regularization in AF. Conclusions Temporal and spatial regularization of persistent AF after PVI identifies patients in whom stepwise ablation subsequently terminates AF and prevents recurrence. PMID:21699850

  16. Surgical Repair of Right Atrial Wall Rupture after Blunt Chest Trauma

    PubMed Central

    Telich-Tarriba, Jose E.; Anaya-Ayala, Javier E.; Reardon, Michael J.

    2012-01-01

    Right atrial wall rupture after blunt chest trauma is a catastrophic event associated with high mortality rates. We report the case of a 24-year-old woman who was ejected 40 feet during a motor vehicle accident. Upon presentation, she was awake and alert, with a systolic blood pressure of 100 mmHg. Chest computed tomography disclosed a large pericardial effusion; transthoracic echocardiography confirmed this finding and also found right ventricular diastolic collapse. A diagnosis of cardiac tamponade with probable cardiac injury was made; the patient was taken to the operating room, where median sternotomy revealed a 1-cm laceration of the right atrial appendage. This lesion was directly repaired with 4-0 polypropylene suture. Her postoperative course was uneventful, and she continued to recover from injuries to the musculoskeletal system. This case highlights the need for a high degree of suspicion of cardiac injuries after blunt chest trauma. An algorithm is proposed for rapid recognition, diagnosis, and treatment of these lesions. PMID:22949784

  17. Contemporary Management of Atrial Fibrillation: Update on Anticoagulation and Invasive Management Strategies

    PubMed Central

    Crandall, Mark A.; Bradley, David J.; Packer, Douglas L.; Asirvatham, Samuel J.

    2009-01-01

    Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Its increasing prevalence, particularly among the elderly, renders it one of the most serious current medical epidemics. Several management questions confront the clinician treating a patient with AF: Should the condition be treated? Is the patient at risk of death or serious morbidity as a result of this diagnosis? If treatment is necessary, is rate control or rhythm control superior? Which patients need anticoagulation therapy, and for how long? This review of articles obtained by a search of the PubMed and MEDLINE databases presents the available evidence that can guide the clinician in answering these questions. After discussing the merits of available therapy, including medications aimed at controlling rate, rhythm, or both, we focus on the present status of ablative therapy for AF. Catheter ablation, particularly targeting the pulmonary veins, is being increasingly performed, although the precise indications for this approach and its effectiveness and safety are being actively investigated. We briefly discuss other invasive options that are less frequently used, such as pacemakers, defibrillators, left atrial appendage closure devices, and the surgical maze procedure. PMID:19567719

  18. Atrial Fibrillation Treatment | NIH MedlinePlus the Magazine

    MedlinePlus

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

  19. Effect of the atrial blanking time on the detection of atrial fibrillation in dual chamber pacing.

    PubMed

    Nowak, B; Kracker, S; Rippin, G; Horstick, G; Vincent, A; Geil, S; Himmrich, E; Meyer, J

    2001-04-01

    Patients with paroxysmal atrial fibrillation (PAF) and dual chamber pacemakers frequently have short postventricular atrial blanking times and sensitive atrial sensing thresholds used to provide reliable detection and mode switching during AF. However, short atrial blanking times increase the risk of atrial sensing of ventricular far-field signals. We evaluated if the length of the atrial blanking time influences the detection of AF. The study included ten patients with a VDDR (n = 7) or DDDR system (n = 3), who presented with AF at 18 follow-up visits. Bipolar atrial sensing was programmed to the most sensitive value. Atrial blanking times were programmed from 100 to 200 ms in 25-ms steps in each patient. Using marker annotation, the following parameters were measured at ten consecutive ventricular beats: VAF = the interval between ventricular stimulus and first sensing of AF; AFS = the number of atrial-sensed events between two ventricular events; and XAF = the interpolated number of atrial-sensed events during atrial blanking time. The intervals between ventricular events and between atrial-sensed event markers showed no significant differences for the five blanking times tested. There was no significant influence of the atrial blanking time onto the measured parameters (least square means +/- standard error) with VAF between 281 +/- 12 and 300 +/- 12 ms (P = NS), AFs between 3.4 +/- 0.2 and 3.6 +/- 0.2 beats (P = NS) and XAF between 1.84 +/- 0.12 and 2.03 +/- 0.12 beats (P = NS). At ventricular rates < 100/min, the atrial sensing of AF in dual chamber pacemakers demonstrated no evidence for deterioration by an increase of the atrial blanking time from 100 to 200 ms. Thus, the risk of ventricular far-field sensing may be reduced without compromising atrial sensing. PMID:11341088

  20. 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

  1. 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

  2. State equations for a spacecraft with maneuvering flexible appendages in terms of quasi-coordinates

    SciTech Connect

    Meirovitch, L.; Kwak, M.K. )

    1989-11-01

    This paper is concerned with the derivation of the state equations of motion for a spacecraft consisting of a main rigid platform and a given number of flexible appendages changing the orientation relative to the main body. The equations are derived by means of Lagrange's equations in terms of quasi-coordinates. Assuming that the appendages represent distributed-parameter members, the state equations of motion are hybrid. Moreover, they are nonlinear. Following spatial discretization and truncation, the hybrid equations reduce to a system of nonlinear discretized state equations, which are more practical for numerical calculations and control design. To illustrate the effect of nonlinearity on the dynamic response during reorientation, a numerical example involving spacecraft with a membrane-like antenna is presented.

  3. Early events in skin appendage formation: induction of epithelial placodes and condensation of dermal mesenchyme.

    PubMed

    Widelitz, R B; Chuong, C M

    1999-12-01

    The formation of skin appendages represents a morphogenetic process through which a homogeneous system is converted into a patterned system. We have pursued molecules involved in the early placode induction and mesenchymal condensation stages of this process. We found that intracellular and extracellular signaling molecules collaborate to position the location of feather primordia and initiate mesenchymal condensations mediated by adhesion molecules. During the inductive stage, cells interact in a fashion best described by a reaction-diffusion mechanism. Thus in early feather morphogenesis, low level adhesion molecules drive cell interactions. The interactions were modulated by extracellular signaling molecules, which eventually increase the level of signaling molecules at sites of feather initiation and subsequently the level of adhesion molecules (Jiang et al, 1999a). These physico-chemical events lead to the formation of dermal condensations and epithelial placodes at sites of feather primordia, thus achieving the earliest and most fundamental events of skin appendage formation: induction. PMID:10674386

  4. 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

  5. MARCKS-like protein is an initiating molecule in axolotl appendage regeneration.

    PubMed

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

    2016-03-10

    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 considerable portion of the body part has been removed. 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. A wound-associated molecule that triggers the initial proliferative response to launch regeneration has remained obscure. Here, 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. The identification of a regeneration-initiating molecule opens the possibility of understanding how to elicit regeneration in other animals. PMID:26934225

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

    PubMed

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

    2015-10-15

    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

  7. 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, non-optically targeted, flexible solar arrays and appendages is a viable, low-cost measurement option for the International Space Station.

  8. [Primary appendagitis epiploica: diagnosis and follow-up with CT (case report)].

    PubMed

    Cakirer, Sinan; Savaş, Mahmut R

    2004-06-01

    Primary appendagitis epiploica is a rare benign self-limiting inflammatory condition of the colonic epiploic appendices. It causes acute localized abdominal pain thought to be the result of torsion or spontaneous vascular thrombosis of epiploic appendices. This is a non-surgical situation that clinically mimics other conditions requiring surgery such as acute diverticulitis or appendicitis. In this report, CT findings of this rare disease are presented at the stage of initial diagnosis and follow-up. PMID:15236131

  9. 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.

  10. Free fatty acid receptor 1 (FFA1/GPR40) agonists: mesylpropoxy appendage lowers lipophilicity and improves ADME properties.

    PubMed

    Christiansen, Elisabeth; Due-Hansen, Maria E; Urban, Christian; Grundmann, Manuel; Schröder, Ralf; Hudson, Brian D; Milligan, Graeme; Cawthorne, Michael A; Kostenis, Evi; Kassack, Matthias U; Ulven, Trond

    2012-07-26

    FFA1 (GPR40) is a new target for treatment of type 2 diabetes. We recently identified the potent FFA1 agonist TUG-469 (5). Inspired by the structurally related TAK-875, we explored the effects of a mesylpropoxy appendage on 5. The appendage significantly lowers lipophilicity and improves metabolic stability while preserving potency, resulting in discovery of the potent FFA1 agonist 13. PMID:22724451

  11. Almanac 2015: atrial fibrillation research in Heart.

    PubMed

    Jawad-Ul-Qamar, Muhammad; Kirchhof, Paulus

    2016-04-01

    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

  12. 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

  13. Coupling dynamic analysis of spacecraft with multiple cylindrical tanks and flexible appendages

    NASA Astrophysics Data System (ADS)

    Wu, Wen-Jun; Yue, Bao-Zeng; Huang, Hua

    2016-02-01

    This paper is mainly concerned with the coupling dynamic analysis of a complex spacecraft consisting of one main rigid platform, multiple liquid-filled cylindrical tanks, and a number of flexible appendages. Firstly, the carrier potential function equations of liquid in the tanks are deduced according to the wall boundary conditions. Through employing the Fourier-Bessel series expansion method, the dynamic boundaries conditions on a curved free-surface under a low-gravity environment are transformed to general simple differential equations and the rigid-liquid coupled sloshing dynamic state equations of liquid in tanks are obtained. The state vectors of rigid-liquid coupled equations are composed with the modal coordinates of the relative potential function and the modal coordinates of wave height. Based on the Bernoulli-Euler beam theory and the D'Alembert's principle, the rigid-flexible coupled dynamic state equations of flexible appendages are directly derived, and the coordinate transform matrixes of maneuvering flexible appendages are precisely computed as time-varying. Then, the coupling dynamics state equations of the overall system of the spacecraft are modularly built by means of the Lagrange's equations in terms of quasi-coordinates. Lastly, the coupling dynamic performances of a typical complex spacecraft are studied. The availability and reliability of the presented method are also confirmed.

  14. The Mother Centriole Appendage Protein Cenexin Modulates Lumen Formation through Spindle Orientation.

    PubMed

    Hung, Hui-Fang; Hehnly, Heidi; Doxsey, Stephen

    2016-03-21

    Establishing apical-basal polarity is instrumental in the functional shaping of a solitary lumen within an acinus. By exploiting micropatterned slides, wound healing assays, and three-dimensional culture systems, we identified a mother centriole subdistal appendage protein, cenexin, as a critical player in symmetric lumen expansion through the control of microtubule organization. In this regard, cenexin was required for both centrosome positioning in interphase cells and proper spindle orientation during mitosis. In contrast, the essential mother centriole distal appendage protein CEP164 did not play a role in either process, demonstrating the specificity of subdistal appendages for these events. Importantly, upon closer examination we found that cenexin depletion decreased astral microtubule length, disrupted astral microtubule minus-end organization, and increased levels of the polarity protein NuMA at the cell cortex. Interestingly, spindle misorientation and NuMA mislocalization were reversed by treatment with a low dose of the microtubule-stabilizing agent paclitaxel. Taken together, these results suggest that cenexin modulates microtubule organization and stability to mediate spindle orientation. PMID:26948879

  15. Setal morphology of grooming appendages in the spider crab, Libinia dubia.

    PubMed

    Wortham, Jen L; LaVelle, Amanda D

    2016-08-01

    In crustaceans, grooming behaviors decrease fouling by removing debris from the exoskeleton and body structures; these grooming behaviors improve respiration, sensory reception, movement, and reproduction. Setal morphologies of the following grooming appendages in the decapod crustacean spider crab Libinia dubia are examined including the first pereiopod (cheliped), first, second, and third maxillipeds (mouthparts), and first, second, and third epipods (internal extensions of the maxillipeds). The objective of this study was to describe setal morphologies of these grooming appendages and to elucidate possible functions and efficiencies of setal structures. Spider crabs are hypothesized to have elaborate setal morphologies, mainly for cleaning specialized decorating setae as well as for cleaning inside the gill chamber, which has a higher likelihood of becoming fouled compared to other decapods such as shrimps. Fourteen setal types are documented and included several varieties of serrate and pappose setae as well as simple setae, cuspidate setae, papposerrate setae, and canoe setae. Maxillipodal epipods in the gill chamber are free of fouling, suggesting the setation on the third maxilliped protopod has an efficient functional morphology in removing debris before water enters the gill chamber. Serrate setae may function for detangling and separating structures whereas pappose setae may function for fine detailed grooming. The cheliped is the only grooming appendage that can reach decorating setae and it contains only pappose setae; thus decorating setae is not likely groomed in a manner that would greatly decrease fouling. J. Morphol. 277:1045-1061, 2016. © 2016 Wiley Periodicals, Inc. PMID:27149925

  16. Sculpting skin appendages out of epidermal layers via temporally and spatially regulated apoptotic events.

    PubMed

    Chang, Chung-Hsing; Yu, Mingke; Wu, Ping; Jiang, Ting-Xin; Yu, Hsin-Su; Widelitz, Randall B; Chuong, Cheng-Ming

    2004-06-01

    Complex skin appendages are built from the epidermal cells through various cell events. Here we used TUNEL and caspase-3 immuno-localization to examine apoptosis in feather morphogenesis. We deduced three modes. In Mode 1A, apoptosis occurs within the localized growth zone (LoGZ) to regulate growth (feather buds). In Mode 1B, morphogen secreting cells are present adjacent to LoGZ and apoptosis may work to remove such signaling centers (barb ridges). In Mode 2, keratinocytes apoptosed before terminal differentiation and left spaces between branches (marginal plate). In Mode 3A, keratinocytes cornified and flaked off to free skin appendages (feather sheath, pulp epithelium). In Mode 3B, keratinized apoptosed epithelial cells became permanent structures (rachis, ramus, barbules). Thus, different apoptotic modes can have different impacts on morphogenesis. We further tested effects of imbalanced Shh on apoptosis. Shh suppression reduced marginal plate apoptosis and caused abnormal differentiation of barbule plates. Shh over-expression enhanced proliferation in barb ridges. Expression of Patched in the barbule plate epithelia implies a paracrine mechanism. The current work complements our recent work on LoGZ to show how adding and removing cell masses in temporally and spatially specific ways are coordinated to sculpt skin appendages from epidermal layers. PMID:15175023

  17. Attenuated response of L-type calcium current to nitric oxide in atrial fibrillation

    PubMed Central

    Rozmaritsa, Nadiia; Christ, Torsten; Van Wagoner, David R.; Haase, Hannelore; Stasch, Johannes-Peter; Matschke, Klaus; Ravens, Ursula

    2014-01-01

    Aim Nitric oxide (NO) synthesized by cardiomyocytes plays an important role in the regulation of cardiac function. Here, we studied the impact of NO signalling on calcium influx in human right atrial myocytes and its relation to atrial fibrillation (AF). Methods and results Right atrial appendages (RAAs) were obtained from patients in sinus rhythm (SR) and AF. The biotin-switch technique was used to evaluate endogenous S-nitrosylation of the α1C subunit of L-type calcium channels. Comparing SR to AF, S-nitrosylation of Ca2+ channels was similar. Direct effects of the NO donor S-nitroso-N-acetyl-penicillamine (SNAP) on L-type calcium current (ICa,L) were studied in cardiomyocytes with standard voltage-clamp techniques. In SR, ICa,L increased with SNAP (100 µM) by 48%, n/N = 117/56, P < 0.001. The SNAP effect on ICa,L involved activation of soluble guanylate cyclase and protein kinase A. Specific inhibition of phosphodiesterase (PDE)3 with cilostamide (1 µM) enhanced ICa,L to a similar extent as SNAP. However, when cAMP was elevated by PDE3 inhibition or β-adrenoceptor stimulation, SNAP reduced ICa,L, pointing to cGMP–cAMP cross-regulation. In AF, the stimulatory effect of SNAP on ICa,L was attenuated, while its inhibitory effect on isoprenaline- or cilostamide-stimulated current was preserved. cGMP elevation with SNAP was comparable between the SR and AF group. Moreover, the expression of PDE3 and soluble guanylate cyclase was not reduced in AF. Conclusion NO exerts dual effects on ICa,L in SR with an increase of basal and inhibition of cAMP-stimulated current, and in AF NO inhibits only stimulated ICa,L. We conclude that in AF, cGMP regulation of PDE2 is preserved, but regulation of PDE3 is lost. PMID:24336332

  18. Tailored treatment strategies: a new approach for modern management of atrial fibrillation.

    PubMed

    Van Gelder, I C; Hobbelt, A H; Marcos, E G; Schotten, U; Cappato, R; Lewalter, T; Schwieler, J; Rienstra, M; Boriani, G

    2016-05-01

    Atrial fibrillation (AF) is not benign. Cardiovascular diseases and risk factors differ importantly amongst patients. Careful phenotyping with the aim to start tailored therapy may improve outcome and quality of life. Furthermore, structural remodelling plays an important role in initiation and progression of AF. Therapies that interfere in the remodelling processes are promising because they may modify the atrial substrate. However, success is still limited probably due to variations in the underlying substrate in individual patients. The most favourable effects of lifestyle changes on success of rhythm control have been demonstrated in obese patients with AF. Differences in genotype may also play an important role. Common gene variants have been associated with recurrence of AF after electrical cardioversion, antiarrhythmic drug therapy and catheter ablation. Therefore, both phenotyping and genotyping may become useful for patient selection in the future. Beside the choice of rate or rhythm control, and type of rhythm control, prevention of complications associated with AF may also differ depending on genotype and phenotype. Efficacy of stroke prevention has been well established, but bleeding remains a clinically relevant problem. Risk stratification is still cumbersome, especially in low-risk patients and in those with a high bleeding risk. The decision whether to start anticoagulation (and if so which type of anticoagulant) or, alternatively, to implant an occlusion device of the left atrial appendage may also be improved by genotyping and phenotyping. In this review, we will summarize new insights into the roles of phenotype and genotype in generating more tailored treatment strategies in patients with AF and discuss several patient-tailored treatment options. PMID:26991684

  19. Aspirin Often Wrongly Prescribed for Atrial Fibrillation

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_159459.html Aspirin Often Wrongly Prescribed for Atrial Fibrillation Blood thinners -- not aspirin -- dramatically cut the risk of stroke, researchers say ...

  20. Azathioprine-induced atrial fibrillation

    PubMed Central

    Dogan, Pinar; Grbovic, Enis; Inci, Sinan; Bayraktar, Fatih; Cagli, Kumral

    2015-01-01

    Summary Azathioprine, a purine analogue that competitively inhibits the biosynthesis of purine nucleotides, is used in a wide range of conditions. Although its side-effects are well known, cardiac side effects like paroxysmal atrial fibrillation (AF) are based on only a few case reports. We describe here the case of a 55-year-old woman with primary biliary cirrhosis who presented a first-detected, symptomatic AF 2 h after azathioprine therapy which resolved after discontinuation of the drug with no predisposing factors for supraventricular arrhythmias (systemic hypertension, diabetes or coronary artery disease). The temporal coincidence of atrial fibrillation and azathioprine intake and disappearance of the AF episode after discontinuation of therapy allows us to suggest an intrinsic pro-arrhythmic effect of azathioprine. Therefore, physicians should be aware of this problem when this drug is administered. PMID:26668782

  1. Atrial fibrillation: inflammation in disguise?

    PubMed

    Lappegård, K T; Hovland, A; Pop, G A M; Mollnes, T E

    2013-08-01

    Atrial fibrillation is highly prevalent, and affected patients are at an increased risk of a number of complications, including heart failure and thrombo-embolism. Over the past years, there has been increasing interest in the role of inflammatory processes in atrial fibrillation, from the first occurrence of the arrhythmia to dreaded complications such as strokes or peripheral emboli. As the standard drug combination which aims at rate control and anticoagulation only offers partial protection against complications, newer agents are needed to optimize treatment. In this paper, we review recent knowledge regarding the impact of inflammation on the occurrence, recurrence, perpetuation and complications of the arrhythmia, as well as the role of anti-inflammatory therapies in the treatment for the disease. PMID:23672430

  2. Wavelength index at three atrial sites in patients with paroxysmal atrial fibrillation.

    PubMed

    Padeletti, L; Michelucci, A; Giovannini, T; Porciani, M C; Bamoshmoosh, M; Mezzani, A; Chelucci, A; Pieragnoli, P; Gensini, G F

    1995-06-01

    The purpose of this study was to evaluate the wavelength index (WLI) at three atrial sites in a group of 23 patients with recurrent episodes of lone paroxysmal atrial fibrillation (LPAF) and a control group (n = 20). All patients underwent programmed atrial stimulation (paced cycle length = 600 ms) at high, medium, and low lateral right atrial wall. P wave duration, sinus cycle length, and corrected sinus node recovery time were not significantly different between the two study groups. WLI was calculated according to the following formulas: atrial effective refractory period (AERP)/duration of atrial extrastimulus electrogram (A2) or AERP/A2 + atrial latency; and atrial functional refractory period (AFRP)/A2. WLI was significantly shorter in LPAF than in the control group at each of the paced atrial sites independently of the formula used. Duration of premature atrial electrogram appeared to play the major role in determining the difference in WLI between patients with paroxysmal atrial fibrillation and the control group. PMID:7659580

  3. Atrial distension of isolated rabbit hearts and release of atrial natriuretic factor

    SciTech Connect

    Synhorst, D.P.; Gutkowska, J. Clinical Research Institute of Montreal, Quebec )

    1988-08-01

    Interventions that increase atrial pressures in humans or laboratory animals release atrial natriuretic factor (ANF) into the circulation. The authors studied the relation between distension of the right or left atrium and release of ANF in retrograde-perfused isolated rabbit hearts. A fluid-filled balloon within the right or left atrium was inflated to a mean pressure of 5, 10, 15, or 20 mmHg, and ANF in the cardiac effluent was measured by radioimmunoassay. The slope of the regression line relating ANF release to atrial distending pressure was steeper for the left than right atrium, indicating that, at comparable increases in mean pressures, the left atrium releases more ANF than does the right atrium. Left atrial tissue concentration ANF was greater than right atrial. In contrast to previous studies showing right atrial dominance in rats, the left atria of isolated, perfused rabbit hearts contain more ANF and release more in response to atrial distension.

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

    PubMed

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

    2016-03-01

    Typical, cavotricuspid-dependent atrial flutter is the most common atrial macroreentry tachycardia. The incidence of atrial flutter (typical and atypical forms) is age-dependent with 5/100,000 in patients less than 50 years and approximately 600/100,000 in subjects > 80 years of age. Concomitant heart failure or pulmonary disease further increases the risk of typical atrial flutter.Patients with atrial flutter may present with symptoms of palpitations, reduced exercise capacity, chest pain, or dyspnea. The risk of thromboembolism is probably similar to atrial fibrillation; therefore, the same antithrombotic prophylaxis is required in atrial flutter patients. Acutely symptomatic cases may be subjected to cardioversion or pharmacologic rate control to relieve symptoms. Catheter ablation of the cavotricuspid isthmus represents the primary choice in long-term therapy, associated with high procedural success (> 97 %) and low complication rates (0.5 %).This article represents the third part of a manuscript series designed to improve professional education in the field of cardiac electrophysiology. Mechanistic and clinical characteristics as well as management of isthmus-dependent atrial flutter are described in detail. Electrophysiological findings and catheter ablation of the arrhythmia are highlighted. PMID:26846223

  5. Blocked atrial bigeminy presenting with bradycardia.

    PubMed

    Akdeniz, Celal; Tanidir, Ibrahim Cansaran; Tuzcu, Volkan

    2012-01-01

    Blocked premature atrial contractions can cause bradycardia by resetting sinoatrial node and prolonging the RR intervals. Herein, we report the management of a patient with frequent premature atrial contractions in bigeminal pattern. The patient presented with symptomatic bradycardia and was successfully treated with propafenone. PMID:22469245

  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. PMID:21524488

  7. 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.

  8. 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

  9. Left atrial strain: A useful index in atrial fibrillation.

    PubMed

    Cameli, Matteo; Mandoli, Giulia Elena; Loiacono, Ferdinando; Sparla, Stefania; Iardino, Elisabetta; Mondillo, Sergio

    2016-10-01

    Left atrial (LA) strain is a speckle tracking echocardiography (STE)-derived parameter applied to the analysis of chamber function that provides highly reproducible measures of LA deformation by a non-Doppler, angle-independent quantification. In recent years, data regarding accuracy and clinical application of LA strain are rapidly increasing. This review describes the main features of LA strain and examines the role of STE in the evaluation of various aspects of AF, as the risk of developing the arrhythmia in general population, the evaluation of LA fibrosis and LA impairment, the quantification of cardioembolic risk and of recurrence after cardioversion or ablation therapies. PMID:27389443

  10. Aliskiren protecting atrial structural remodeling from rapid atrial pacing in a canine model.

    PubMed

    Zhao, Zhiqiang; Chen, Yan; Li, Weimin; Wang, Xinghua; Li, Jian; Yang, Wansong; Cheng, Lijun; Liu, Tong; Liu, Enzhao; Li, Guangping

    2016-08-01

    Atrial fibrillation (AF) contributing to the increasing mortality risk is the most common disease in clinical practice. Owing to the side effects and relative inefficacy of current antiarrhythmic drugs, some research focuses on renin-angiotensin-aldosterone system (RAS) for finding out the new treatment of AF. The purpose of this study is to confirm whether aliskiren as a proximal inhibitor of renin, which completely inhibits RAS, has beneficial effects on atrial structural remodeling in AF. In this study, rapid atrial pacing was induced at 500 beats per minute for 2 weeks in a canine model. A different dose of aliskiren was given orally for 2 weeks before rapid atrial pacing. HE staining and Masson's staining were used for analysis of myocardial fibrosis. TGF-β1, signal pathways, and pro-inflammatory cytokines were shown for the mechanism of structural remodeling after the treatment of aliskiren. Serious atrial fibrosis was induced by rapid atrial pacing, followed by the elevated TGF-β1, upregulated MEK and ERK1/2, and increased inflammatory factors. Aliskiren could apparently improve myocardial fibrosis by reducing the expression of TGF-β1, inhibiting MEK and ERK1/2 signal pathways, and decreasing IL-18 and TLR4 in both serum and atrial tissue. In conclusion, aliskiren could prevent atrial structural remodeling from rapid atrial pacing for 2 weeks. Aliskiren may play a potential beneficial role in the treatment of AF induced by rapid atrial pacing. PMID:27118660

  11. 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

  12. Atrial fibrillation and physical activity

    PubMed Central

    Bosomworth, N. John

    2015-01-01

    Objective To review the evidence on the effects of various levels of physical activity (PA) on the incidence of atrial fibrillation (AF) in both the general population and in endurance athletes. Data sources A PubMed search was done initially using the MeSH headings or text words (with the search-field descriptor TIAB [title and abstract]) atrial fibrillation and exercise or physical activity or athlet* or sport*, without additional filters. Conclusions regarding quality and strength of evidence were based on the GRADE (grading of recommendations, assessment, development, and evaluation) system. Study selection No interventional studies were available. Observational studies were therefore considered acceptable, and, although larger long-term prospective cohort studies were preferred, case-control or cross-sectional trials were also included in this review. Synthesis Available evidence suggests a dose-response association linking increased exercise levels with reduced incident AF in women. The same is true in men at low and moderate levels of exertional activity. In men only, high levels of PA are associated with increased risk of AF in most, but not all, studies. This risk is moderate, with a hazard ratio of 1.29 in one of the better studies. The risk of AF for most people who exercise regularly is lower than that of a matched sedentary population. Conclusion Atrial fibrillation is probably less common as PA increases, with a demonstrable dose-response relationship. Exercise at any level should be promoted for its effect on physical well-being and mortality reduction. In men exercising at high levels, beneficial effects on AF might be lost and risk might exceed that of the sedentary population; however, the evidence is neither robust nor consistent. These men should be made aware of this modest increase in risk should they choose to continue to engage in high levels of PA. PMID:26668285

  13. Advances in Atrial Fibrillation Ablation

    PubMed Central

    Darge, Alicia; Reynolds, Matthew R.; Germano, Joseph J.

    2009-01-01

    Atrial Fibrillation (AF) is an increasingly common and costly medical problem.1–3 Given the disappointing efficacy and side effects associated with pharmacological therapy for AF, new treatment options are needed. Over the last decade, advances in our understanding of the mechanisms of AF, coupled with iterative improvements in catheter ablation techniques, have spurred the evolution of catheter ablation for AF from an experimental procedure to an increasingly important treatment option.4 This paper will review recent advances in the approaches and outcomes of AF ablation. PMID:19411729

  14. Atrial Fibrillation Ablation and Stroke.

    PubMed

    Aagaard, Philip; Briceno, David; Csanadi, Zoltan; Mohanty, Sanghamitra; Gianni, Carola; Trivedi, Chintan; Nagy-Baló, Edina; Danik, Stephan; Barrett, Conor; Santoro, Francesco; Burkhardt, J David; Sanchez, Javier; Natale, Andrea; Di Biase, Luigi

    2016-05-01

    Catheter ablation has become a widely available and accepted treatment to restore sinus rhythm in atrial fibrillation patients who fail antiarrhythmic drug therapy. Although generally safe, the procedure carries a non-negligible risk of complications, including periprocedural cerebral insults. Uninterrupted anticoagulation, maintenance of an adequate ACT during the procedure, and measures to avoid and detect thrombus build-up on sheaths and atheters during the procedure, appears useful to reduce the risk of embolic events. This is a review of the incidence, mechanisms, impact, and methods to reduce catheter ablation related cerebral insults. PMID:27150179

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

    PubMed Central

    Loardi, Claudia; Alamanni, Francesco; Galli, Claudia; Naliato, Moreno; Veglia, Fabrizio; Zanobini, Marco; Pepi, Mauro

    2015-01-01

    Background. Maze procedure aims at restoring sinus rhythm (SR) and atrial contractility (AC). This study evaluated multiple aspects of AC recovery and their relationship with SR regain after ablation. Methods. 122 mitral and fibrillating patients underwent radiofrequency Maze. Rhythm check and echocardiographic control of biatrial contractility were performed at 3, 6, 12, and 24 months postoperatively. A multivariate Cox analysis of risk factors for absence of AC recuperation was applied. Results. At 2-years follow-up, SR was achieved in 79% of patients. SR-AC coexistence increased from 76% until 98%, while biatrial contraction detection augmented from 84 to 98% at late stage. Shorter preoperative arrhythmia duration was the only common predictor of SR-AC restoring, while pulmonary artery pressure (PAP) negatively influenced AC recuperation. Early AC restoration favored future freedom from arrhythmia recurrence. Minor LA dimensions correlated with improved future A/E value and vice versa. Right atrial (RA) contractility restoring favored better left ventricular (LV) performance and volumes. Conclusions. SR and left AC are two interrelated Maze objectives. Factors associated with arrhythmia “chronic state” (PAP and arrhythmia duration) are negative predictors of procedural success. Our results suggest an association between postoperative LA dimensions and “kick” restoring and an influence of RA contraction onto LV function. PMID:26229956

  16. Schizophyllans carrying oligosaccharide appendages as potential candidates for cell-targeted antisense carrier.

    PubMed

    Hasegawa, Teruaki; Fujisawa, Tomohisa; Numata, Munenori; Matsumoto, Takahiro; Umeda, Mariko; Karinaga, Ryouji; Mizu, Masami; Koumoto, Kazuya; Kimura, Taro; Okumura, Shiro; Sakurai, Kazuo; Shinkai, Seiji

    2004-11-01

    Schizophyllans carrying beta-lactoside and alpha-mannoside appendages were prepared from native schizophyllan through NaIO4 oxidation followed by reductive amination using aminoethyl-beta-lactoside and alpha-mannoside, respectively. The resulting schizophyllans form stable macromolecular complexes with polynucleotides, such as poly(C) and poly(dA). Specific affinity between these macromolecular complexes and saccharide-binding proteins was demonstrated by surface plasmon resonance and agarose gel staining assays. beta-lactoside-appended schizophyllan enhanced an antisense activity in hepatocytes which express lactoside-binding proteins on their cell surfaces. PMID:15505713

  17. Carbohydrate metabolism during vertebrate appendage regeneration: What is its role? How is it regulated?: A postulation that regenerating vertebrate appendages facilitate glycolytic and pentose phosphate pathways to fuel macromolecule biosynthesis

    PubMed Central

    Love, Nick R; Ziegler, Mathias; Chen, Yaoyao; Amaya, Enrique

    2014-01-01

    We recently examined gene expression during Xenopus tadpole tail appendage regeneration and found that carbohydrate regulatory genes were dramatically altered during the regeneration process. In this essay, we speculate that these changes in gene expression play an essential role during regeneration by stimulating the anabolic pathways required for the reconstruction of a new appendage. We hypothesize that during regeneration, cells use leptin, slc2a3, proinsulin, g6pd, hif1α expression, receptor tyrosine kinase (RTK) signaling, and the production of reactive oxygen species (ROS) to promote glucose entry into glycolysis and the pentose phosphate pathway (PPP), thus stimulating macromolecular biosynthesis. We suggest that this metabolic shift is integral to the appendage regeneration program and that the Xenopus model is a powerful experimental system to further explore this phenomenon. PMID:24264888

  18. Carbohydrate metabolism during vertebrate appendage regeneration: what is its role? How is it regulated?: A postulation that regenerating vertebrate appendages facilitate glycolytic and pentose phosphate pathways to fuel macromolecule biosynthesis.

    PubMed

    Love, Nick R; Ziegler, Mathias; Chen, Yaoyao; Amaya, Enrique

    2014-01-01

    We recently examined gene expression during Xenopus tadpole tail appendage regeneration and found that carbohydrate regulatory genes were dramatically altered during the regeneration process. In this essay, we speculate that these changes in gene expression play an essential role during regeneration by stimulating the anabolic pathways required for the reconstruction of a new appendage. We hypothesize that during regeneration, cells use leptin, slc2a3, proinsulin, g6pd, hif1α expression, receptor tyrosine kinase (RTK) signaling, and the production of reactive oxygen species (ROS) to promote glucose entry into glycolysis and the pentose phosphate pathway (PPP), thus stimulating macromolecular biosynthesis. We suggest that this metabolic shift is integral to the appendage regeneration program and that the Xenopus model is a powerful experimental system to further explore this phenomenon. Also watch the Video Abstract. PMID:24264888

  19. A Functional Polymorphism C-509T in TGFβ-1 Promoter Contributes to Susceptibility and Prognosis of Lone Atrial Fibrillation in Chinese Population

    PubMed Central

    Røe, Oluf Dimitri; Chen, Xin; Chen, Yijiang; Wang, Dongjin

    2014-01-01

    Transforming growth factor-β1 (TGF-β1) is an important mediator of atrial fibrosis and atrial fibrillation (AF). But the involved genetic mechanism is unknown. Herein, the TGF-β1 C-509T polymorphism (rs1800469) was genotyped in a case-control study of 840 patients and 845 controls in Chinese population to explore the association between the polymorphism and susceptibility and prognosis of lone AF. As a result, the CT and/or TT genotypes had an increased lone AF risk [adjusted odds ratio (OR) = 1.50 for CT, OR = 3.72 for TT, and OR = 2.15 for CT/TT], compared with the TGF-β1CC genotype. Moreover, patients carrying CT/TT genotypes showed a higher possibility of AF recurrence after catheter ablation, compared with patients carrying CC genotype. In a genotype-phenotype correlation analysis using 24 normal left atrial appendage samples, increasing gradients of atrial TGF-β1 expression levels positively correlated with atrial collagen volume fraction were identified in samples with CC, CT and TT genotypes. The in vitro luciferase assays also showed a higher luciferase activity of the -509T allele than that of the -509C allele. In conclusion, the TGF-β1 C-509T polymorphism is involved in the etiology of lone AF and thus may be a marker for genetic susceptibility to lone AF and predicting prognosis after catheter ablation in Chinese populations. Therefore, we provide new information about treatment strategies and our understanding of TGF-β1 in AF. PMID:25402477

  20. Altered expression of hyperpolarization-activated cyclic nucleotide-gated channels and microRNA-1 and -133 in patients with age-associated atrial fibrillation

    PubMed Central

    LI, YAO-DONG; HONG, YI-FAN; YUSUFUAJI, YUEERGULI; TANG, BAO-PENG; ZHOU, XIAN-HUI; XU, GUO-JUN; LI, JIN-XIN; SUN, LIN; ZHANG, JIANG-HUA; XIN, QIANG; XIONG, JIAN; JI, YU-TONG; ZHANG, YU

    2015-01-01

    Hyperpolarization-activated cyclic nucleotide-gated (HCN) cation channels mediate pacemaker currents in the atrium. The microRNA (miR) families miR-1 and miR-133 regulate the expression of multiple genes involved in myocardial function, including HCN channels. It was hypothesized that age-dependent changes in HCN2, HCN4, miR-1 and miR-133 expression may contribute to age-associated atrial fibrillation, and therefore the correlation between expression levels, among adult (≤65 years) and aged patients (≥65 years), and sinus rhythm was determined. Right atrial appendage samples were collected from 60 patients undergoing coronary artery bypass grafting. Reverse transcription-quantitative polymerase chain reaction (PCR) and western blot analyses were performed in order to determine target RNA and protein expression levels. Compared with aged patients with sinus rhythm, aged patients with atrial fibrillation exhibited significantly higher HCN2 and HCN4 channel mRNA and protein expression levels (P<0.05), but significantly lower expression levels of miR-1 and miR-133 (P<0.05). In addition, aged patients with sinus rhythm exhibited significantly higher expression levels of HCN2 and HCN4 channel mRNA and protein (P<0.05), but significantly lower expression levels of miR-1 and -133 (P<0.05), compared with those of adult patients with sinus rhythm. Expression levels of HCN2 and HCN4 increased with age, and a greater increase was identified in patients with age-associated atrial fibrillation compared with that in those with aged sinus rhythm. These electrophysiological changes may contribute to the induction of ectopic premature beats that trigger atrial fibrillation. PMID:26005035

  1. Stroke risk assessment in atrial fibrillation: risk factors and markers of atrial myopathy.

    PubMed

    Calenda, Brandon W; Fuster, Valentin; Halperin, Jonathan L; Granger, Christopher B

    2016-09-01

    Atrial fibrillation (AF) is a complex phenomenon associated with electrical, mechanical, and structural abnormalities of the atria. Ischaemic stroke in AF is only partially understood, but the mechanisms are known to be related to the atrial substrate as well as the atrial rhythm. The temporal dissociation between timing of AF and occurrence of stroke has led to the hypothesis that fibrotic, prothrombotic atrial tissue is an important cause of thrombus formation in patients with AF, independent of the atrial rhythm. Current stroke risk scores are practical, but limited in their capacity to predict stroke risk accurately in individual patients. Stroke prediction might be improved by the addition of emerging risk factors, many of which are expressions of atrial fibrosis. The use of novel parameters, including clinical criteria, biomarkers, and imaging data, might improve stroke risk prediction and inform on optimal treatment for patients with AF and perhaps individuals only at risk of AF. PMID:27383079

  2. An adult with a sinus venosus atrial septal defect and dilated cardiomyopathy

    PubMed Central

    Oakley, Luke; Foley, Sean; Cox, Justin; Seidensticker, Daniel

    2014-01-01

    Dilated cardiomyopathy, heart failure and atrial septal defects are well-recognised entities in isolation, but are rarely seen together. Now that 90% of children with congenital heart disease survive into adulthood, such combinations of disease are increasingly seen in adult cardiology. While most young patients with dilated cardiomyopathy respond well to medical therapy, some do not, and require more invasive management. We describe a 32 year-old man with dilated cardiomyopathy and a sinus venosus-type atrial septal defect associated with a remarkable pulmonary to systemic flow ratio of 5:1. We propose that the atrial septal defect blunted his heart failure symptoms by serving as a ‘pop-off’ valve and limiting pulmonary congestion. The patient ultimately failed medical management and received a left ventricular assist device. The case is presented along with a discussion of this unique pathophysiology and a brief review of the literature in this rapidly evolving field. PMID:24855073

  3. Acute treatment of atrial fibrillation.

    PubMed

    Kowey, P R; Marinchak, R A; Rials, S J; Filart, R A

    1998-03-12

    Atrial fibrillation (AFib) is a common clinical entity, responsible for significant morbidity and mortality, but it also accounts for a large percentage of healthcare dollar expenditures. Efforts to treat this arrhythmia in the past have focused on subacute antithrombotic therapy and eventually use of antiarrhythmic drugs for maintenance of sinus rhythm. However, there has been a growing interest in the concept of acute electrical and pharmacologic conversion. This treatment strategy has a number of benefits, including immediate alleviation of patient symptoms, avoidance of antithrombotic therapy, and prevention of electrophysiologic remodeling, which is thought to contribute to the perpetuation of the arrhythmia. There is also increasing evidence that this is a cost-effective strategy in that it may obviate admission to the hospital and the cost of long-term therapy. This article represents a summary of the treatments that may be used acutely to control the ventricular response to AFib, prevent thromboembolic events, and provide for acute conversion either pharmacologically or electrically. It includes information on modalities that are currently available and those that are under active development. We anticipate that an active, acute treatment approach to AFib and atrial flutter will become the therapeutic norm in the next few years, especially as the benefits of these interventions are demonstrated in clinical trials. PMID:9525568

  4. The atrial T wave: The elusive electrocardiographic wave exposed by a case of shifting atrial pacemaker.

    PubMed

    Langley, Philip; Caldwell, Jane

    2016-01-01

    The atrial T wave (Ta wave) is the body surface manifestation of atrial repolarisation and, unlike the P wave (atrial depolarisation), is little recognised. We report the case of a patient with shifting pacemaker which clearly demonstrates the effect of the Ta wave on ST segment and T wave. A simple conceptual model is used to explain the observed phenomenon. The case serves as a reminder of this often forgotten ECG wave and its potential effects on other ECG features. PMID:27215648

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

    PubMed

    Gehrke, Andrew R; Shubin, Neil H

    2016-09-01

    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

  6. 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. PMID:26091749

  7. 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

  8. Ultrastructural study and ontogenesis of the appendages and related musculature of Paraspadella (Chaetognatha).

    PubMed

    Casanova, J-P; Duvert, M; Goto, T

    2003-10-01

    A lineage of benthic chaetognaths has developed limb-like appendages on the caudal part of the body, resulting from a local modification of the lateral fins, which are folds of the epidermis and have a role in balance when swimming. The most complex are those of Paraspadella gotoi which are used as props with the tip of the tail, allowing an elaborated mating behaviour comprising different movements: complete erection of the body, swings and jumps, astonishing for so simple-bodied animals. In the tail, the epidermis and the connective tissue, together with the longitudinal musculature, are involved in this innovation. All the components of the fins, i.e. connective tissue, fin rays and multilayered epidermic cells are conserved, but their function has changed. The movements of appendages are adjusted by one pair of small appendicular muscles localised in the body wall, while posture movements of the body are allowed by four longitudinal bundles of raising muscle. These two new muscles have successively appeared in the evolutive series previously described in Paraspadella. They have definitely arisen from the secondary muscle: the two lateral bundles for the former, and the two dorsal and two ventral ones for the latter. All are supercontracting muscles, a muscle kind also observed in the other benthic genus Spadella, but unknown in planktonic and benthoplanktonic chaetognaths. PMID:14517101

  9. 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. PMID:21350485

  10. Border of Notch activity establishes a boundary between the two dorsal appendage tube cell types.

    PubMed

    Ward, Ellen J; Zhou, Xiaofeng; Riddiford, Lynn M; Berg, Celeste A; Ruohola-Baker, Hannele

    2006-09-15

    Boundaries establish and maintain separate populations of cells critical for organ formation. We show that Notch signaling establishes the boundary between two types of post-mitotic epithelial cells, the Rhomboid- and the Broad-positive cells. These cells will undergo morphogenetic movements to generate the two sides of a simple organ, the dorsal appendage tube of the Drosophila egg chamber. The boundary forms due to a difference in Notch levels in adjacent cells. The Notch expression pattern mimics the boundary; Notch levels are high in Rhomboid cells and low in Broad cells. Notch(-) mutant clones generate an ectopic boundary: ectopic Rhomboid cells arise in Notch(+) cells adjacent to the Notch(-) mutant cells but not further away from the clonal border. Pangolin, a component of the Wingless pathway, is required for Broad expression and for rhomboid repression. We further show that Broad represses rhomboid cell autonomously. Our data provide a foundation for understanding how a single row of Rhomboid cells arises adjacent to the Broad cells in the dorsal appendage primordia. Generating a boundary by the Notch pathway might constitute an evolutionarily conserved first step during organ formation in many tissues. PMID:16828735

  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. PMID:24780931

  12. Time-varying modal parameters identification of a spacecraft with rotating flexible appendage by recursive algorithm

    NASA Astrophysics Data System (ADS)

    Ni, Zhiyu; Mu, Ruinan; Xun, Guangbin; Wu, Zhigang

    2016-01-01

    The rotation of spacecraft flexible appendage may cause changes in modal parameters. For this time-varying system, the computation cost of the frequently-used singular value decomposition (SVD) identification method is high. Some control problems, such as the self-adaptive control, need the latest modal parameters to update the controller parameters in time. In this paper, the projection approximation subspace tracking (PAST) recursive algorithm is applied as an alternative method to identify the time-varying modal parameters. This method avoids the SVD by signal subspace projection and improves the computational efficiency. To verify the ability of this recursive algorithm in spacecraft modal parameters identification, a spacecraft model with rapid rotational appendage, Soil Moisture Active/Passive (SMAP) satellite, is established, and the time-varying modal parameters of the satellite are identified recursively by designing the input and output signals. The results illustrate that this recursive algorithm can obtain the modal parameters in the high signal noise ratio (SNR) and it has better computational efficiency than the SVD method. Moreover, to improve the identification precision of this recursive algorithm in the low SNR, the wavelet de-noising technology is used to decrease the effect of noises.

  13. Robotic and mathematical modeling reveal general principles of appendage control and coordination in terrestrial locomotion

    NASA Astrophysics Data System (ADS)

    McInroe, Benjamin; Astley, Henry; Gong, Chaohui; Kawano, Sandy; Schiebel, Perrin; Choset, Howie; Goldman, Daniel I.

    The transition from aquatic to terrestrial life presented new challenges to early walkers, necessitating robust locomotion on complex, flowable substrates (e.g. sand, mud). Locomotion on such substrates is sensitive to limb morphology and kinematics. Although early walker morphologies are known, principles of appendage control remain elusive. To reveal limb control strategies that facilitated the invasion of land, we study both robotic and mathematical models. Robot experiments show that an active tail is critical for robust locomotion on granular media, enabling locomotion even with poor foot placement and limited ability to lift the body. Using a granular resistive force theory model, we construct connection vector fields that reveal how appendage coordination and terrain inclination impact locomotor performance. This model replicates experimental results, showing that moving limbs/tail in phase is most effective (suggesting a locomotor template). Varying limb trajectories and contacts, we find gaits for which tail use can be neutral or harmful, suggesting limb-tail coordination to be a nontrivial aspect of locomotion. Our findings show that robot experiments coupled with geometric mechanics provide a general framework to reveal principles of robust terrestrial locomotion. This work was supported by NSF PoLS.

  14. Theoretical and Experimental Studies of Energy Exchange from Jackrabbit Ears and Cylindrically Shaped Appendages

    PubMed Central

    Wathen, Patricia; Mitchell, John W.; Porter, Warren P.

    1971-01-01

    Convection properties of jackrabbit ears were examined in a wind tunnel and in the field in an attempt to study the possible thermal role of the large ears. This work was part of a study on energy exchange of appendages. Cylindrical copper models of various shapes, aluminum castings of domestic and jackrabbit ears, and an amputated jackrabbit ear were studied in a wind tunnel (a) to define the range for convective heat loss for appendages of various shapes, and (b) to study the effect on convection of model shape and orientation to the wind. Shape, i.e. length and closure, proved important. Orientation to the wind produced no consistent or significant variation in the convection coefficient. The convection coefficients from the ear castings fell within the range generated from the cylindrical models. The convection coefficients for the amputated rabbit ear fell partially within the range. Net thermal radiation loss at midday from the jackrabbit ears was found to be small. Convection from the ears, however, could account for the loss of over 100% of the animal's metabolic heat at an air temperature of 30°C. If air temperature exceeds body temperature, the animal must either store heat or resort to the evaporation of water. ImagesFIGURE 1FIGURE 2 PMID:5134209

  15. Conserved features and evolutionary shifts of the EDA signaling pathway involved in vertebrate skin appendage development.

    PubMed

    Pantalacci, Sophie; Chaumot, Arnaud; Benoît, Gérard; Sadier, Alexa; Delsuc, Frédéric; Douzery, Emmanuel J P; Laudet, Vincent

    2008-05-01

    It is widely accepted that evolutionary changes in conserved developmental signaling pathways play an important role in morphological evolution. However, few in silico studies were interested in tracking such changes in a signaling pathway. The Ectodysplasin (EDA) pathway provides an opportunity to fill this gap because it is involved in vertebrate skin appendage development such as scales, teeth, hair, and feathers that take an obvious part in the adaptation of species to their environment. We benefited from the large amount of genomic data now available to explore the evolution of the upstream genes of the EDA pathway. In mammals, these genes are eda (encoding 2 ligands, EDA-A1 and EDA-A2), edar (EDA-A1 receptor), edaradd (EDA receptor [EDAR] adapter), xedar (EDA-A2 receptor), and troy (a XEDAR-related receptor). We show that the evolution of EDA pathway genes combines both strongly conserved features and evolutionary shifts. These shifts are found at different signaling levels (from the ligand to intracellular signaling) and at different taxonomic levels (class, suborder, and genera). Although conserved features likely participate to the similarities found in the early development of vertebrate skin appendages, these shifts might account for innovations and specializations. Moreover, our study demonstrates that we can now benefit from the large number of sequenced vertebrate genomes to explore the evolution of specific signaling pathways and thereby to open new perspectives for developmental biology and evolutionary developmental biology. PMID:18304980

  16. 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

  17. 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

  18. Towards Low Energy Atrial Defibrillation.

    PubMed

    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 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

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

    PubMed

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

    2015-06-01

    The course of cardiac rehabilitation is often altered due to episodes of paroxysmal, predominantly postoperative atrial fibrillation. In symptomatic patients, a TEE-guided cardioversion - preferential DC shock - is indicated. In patients with persistent / permanent atrial fibrillation, a heart rate up to 110 / min and 170 / min at rest and during physical activity should, respectively, be tolerated. Therefore, training should not be quitted by heart rate but rather by load. The antithrombotic management is in addition a great task in treating patients with atrial fibrillation. With the exception of patients with a CHA2DS2-VASc-Score < 1, oral anticoagulation is indicated. Atrial fibrillation has little impact on social aspects, whereas the underlying heart disease and drug treatment (oral anticoagulation) has an important impact. PMID:26115137

  20. 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.

  1. Atrial Fibrillation - Multiple Languages: MedlinePlus

    MedlinePlus

    ... Supplements Videos & Tools You Are Here: Home → Multiple Languages → All Health Topics → Atrial Fibrillation URL of this page: https://medlineplus.gov/languages/atrialfibrillation.html Other topics A-Z A B ...

  2. Atrial Fibrillation - Multiple Languages: MedlinePlus

    MedlinePlus

    ... Supplements Videos & Tools You Are Here: Home → Multiple Languages → All Health Topics → Atrial Fibrillation URL of this page: https://www.nlm.nih.gov/medlineplus/languages/atrialfibrillation.html Other topics A-Z A B ...

  3. Serum Soluble Semaphorin 4D is Associated with Left Atrial Diameter in Patients with Atrial Fibrillation

    PubMed Central

    Xiang, Li; You, Tao; Chen, Jianchang; Xu, Weiting; Jiao, Yang

    2015-01-01

    Background The aim of this study was to evaluate the serum soluble semaphorin 4D (sSema4D) in patients with atrial fibrillation and to investigate the relationship of serum sSema4D with left atrial diameter (LAD). Material/Methods We studied a total of 113 patients who were subdivided into paroxysmal and non-paroxysmal (included persistent and permanent) atrial fibrillation groups, respectively. Another 55 subjects without atrial fibrillation were enrolled as the healthy control group. Serum levels of soluble semaphorin 4D (Sema4D) were measured in all subjects using the enzyme-labeled immunosorbent assay method. We also evaluated the coagulation parameters and left atrial diameters. Results Patients with paroxysmal and non-paroxysmal atrial fibrillation had significantly higher sSema4D level compared with controls (8.50±2.19 ng/mL and 9.30±2.28 ng/mL vs. 6.56±1.27 ng/ml, P<0.05). Serum sSema4D concentrations were elevated in patients with non-paroxysmal atrial fibrillation compared to those with paroxysmal atrial fibrillation (P<0.001). The level of sSema4D was positively correlated with LAD (r=0.606, P<0.001). Multivariate logistic regression analysis revealed that serum sSema4D, LAD, male sex, heart rate, hypertension, and coronary artery disease were associated with atrial fibrillation (P<0.05). Conclusions Serum sSema4D levels are increased in patients with atrial fibrillation and are independently associated with atrial remodeling. PMID:26417899

  4. [Evidence-based treatment of atrial fibrillation].

    PubMed

    Máquez, Manlio F; Gómez Flores, Jorge

    2006-01-01

    Radiofrequency catheter ablation has emerged as a curative therapy for paroxysmal atrial fibrillation based on studies demonstrating the role of triggering foci in the pulmonary veins for the initiation of atrial fibrillation. Catheter ablation is performed by a trans-septal approach using radiofrequency energy at the ostium of each pulmonary vein. Mapping is guided by special catheters. Sequential radiofrequency applications eliminates or dissociates pulmonary vein muscle activity. Although complications exists, this procedure can be curative for these patients. PMID:17017102

  5. Differential Expression Levels of Integrin α6 Enable the Selective Identification and Isolation of Atrial and Ventricular Cardiomyocytes

    PubMed Central

    Wiencierz, Anne Maria; Kernbach, Manuel; Ecklebe, Josephine; Monnerat, Gustavo; Tomiuk, Stefan; Raulf, Alexandra; Christalla, Peter; Malan, Daniela; Hesse, Michael; Bosio, Andreas; Fleischmann, Bernd K.; Eckardt, Dominik

    2015-01-01

    Rationale Central questions such as cardiomyocyte subtype emergence during cardiogenesis or the availability of cardiomyocyte subtypes for cell replacement therapy require selective identification and purification of atrial and ventricular cardiomyocytes. However, current methodologies do not allow for a transgene-free selective isolation of atrial or ventricular cardiomyocytes due to the lack of subtype specific cell surface markers. Methods and Results In order to develop cell surface marker-based isolation procedures for cardiomyocyte subtypes, we performed an antibody-based screening on embryonic mouse hearts. Our data indicate that atrial and ventricular cardiomyocytes are characterized by differential expression of integrin α6 (ITGA6) throughout development and in the adult heart. We discovered that the expression level of this surface marker correlates with the intracellular subtype-specific expression of MLC-2a and MLC-2v on the single cell level and thereby enables the discrimination of cardiomyocyte subtypes by flow cytometry. Based on the differential expression of ITGA6 in atria and ventricles during cardiogenesis, we developed purification protocols for atrial and ventricular cardiomyocytes from mouse hearts. Atrial and ventricular identities of sorted cells were confirmed by expression profiling and patch clamp analysis. Conclusion Here, we introduce a non-genetic, antibody-based approach to specifically isolate highly pure and viable atrial and ventricular cardiomyocytes from mouse hearts of various developmental stages. This will facilitate in-depth characterization of the individual cellular subsets and support translational research applications. PMID:26618511

  6. Atrial fibrillation care improvement collaborative

    PubMed Central

    Robelia, Paul; Kopecky, Stephen; Thacher, Tom

    2015-01-01

    Atrial fibrillation (AF) is an increasingly common cardiac arrhythmia. Many patients with new onset or recurrent AF present to the emergency department and are subsequently admitted to the hospital and seen by cardiology specialists for follow up. In an attempt to address this high utilization of acute health care resources, reduce costs, and improve patient care, our institution instituted a collaborative project between the departments of emergency medicine, cardiology, family medicine, and primary care internal medicine. The project team oversaw development of a new emergency department AF order set, encouraged utilization of a new oral anticoagulant (dabigatran), improved the primary care follow up connection, and deployed a multimodal education plan for primary care providers. Between 2012 and 2014, these interventions resulted in a 17% reduction in total AF per member per month (PMPM) cost, a 28% reduction in AF PMPM inpatient cost, and a 24% reduction in inpatient admissions for AF. PMID:26734425

  7. Adjuvant therapy for atrial fibrillation.

    PubMed

    Mohammed, Khaja S; Kowey, Peter R; Musco, Simone

    2010-01-01

    Atrial fibrillation (AF) is the most common heart rhythm disorder, with increasing prevalence in the aging US population and affecting more than 2.3 million people. Current approaches for managing AF are rate- or rhythm-control strategies, both using anti-thrombotic therapy to prevent thromboembolism. While great advances have been made in understanding the pathophysiology of AF, few new strategies have shown promise in prevention or treatment of AF. Recent data suggest that non-antiarrhythmic medication may be useful in modifying the substrate that allows AF precipitation and perpetuation. This article reviews the data on the role of these agents in the prevention and management of AF as an adjunct to standard therapy. PMID:20014988

  8. Recurrent Left Atrial Botyroid Rhabdomyosarcoma.

    PubMed

    Abay, Günseli; Kocaaslan, Cemal; Günay, Rafet; Doğan, Meryem; Demirtaş, Mahmut Murat

    2016-01-01

    Primary heart tumors are extremely rare and their frequency ranges from approximately 0.01-0.3% in autopsy series. Nearly one quarter of all primary cardiac tumors are malignant tumors such as sarcoma. Rhabdomyosarcoma is the second most common malignant primary tumor of the heart following angiosarcoma.Primary cardiac tumors present with one or more of the symptoms of the classic triad: cardiac symptoms and signs resulting from intracardiac obstruction; signs of systemic embolization; and systemic or constitutional symptoms. The prognosis after surgery is usually excellent in case of benign tumors, but is unfortunately still limited in localized malignant diseases [Butany 2005].In this case report we present a 45-year-old female patient operated three times in 9 years because of left atrial tumor. PMID:27355140

  9. Spontaneous onset of atrial fibrillation

    PubMed Central

    Zemlin, Christian W.; Mitrea, Bogdan G.; Pertsov, Arkady M.

    2009-01-01

    Most commonly, atrial fibrillation is triggered by rapid bursts of electrical impulses originating in the myocardial sleeves of pulmonary veins (PVs). However, the nature of such bursts remains poorly understood. Here, we propose a mechanism of bursting consistent with the extensive empirical information about the electrophysiology of the PVs. The mechanism is essentially non-local and involves the spontaneous initiation of non-sustained spiral waves in the distal end of the muscle sleeves of the PVs. It reproduces the experimentally observed dynamics of the bursts, including their frequency, their intermittent character, and the unusual shape of the electrical signals in the pulmonary veins that are reminiscent of so-called early afterdepolarizations (EADs). PMID:20160895

  10. New anticoagulants for atrial fibrillation.

    PubMed

    Sobieraj-Teague, Magdalena; O'Donnell, Martin; Eikelboom, John

    2009-07-01

    Atrial fibrillation is already the most common clinically significant cardiac arrhythmia and a common cause of stroke. Vitamin K antagonists are very effective for the prevention of cardioembolic stroke but have numerous limitations that limit their uptake in eligible patients with AF and reduce their effectiveness in treated patients. Multiple new anticoagulants are under development as potential replacements for vitamin K antagonists. Most are small synthetic molecules that target factor IIa (e.g., dabigatran etexilate, AZD-0837) or factor Xa (e.g., rivaroxaban, apixaban, betrixaban, DU176b, idrabiotaparinux). These drugs have predictable pharmacokinetics that allow fixed dosing without laboratory monitoring, and are being compared with vitamin K antagonists or aspirin in phase III clinical trials [corrected]. A new vitamin K antagonist (ATI-5923) with improved pharmacological properties compared with warfarin is also being evaluated in a phase III trial. None of the new agents have as yet been approved for clinical use. PMID:19739042

  11. Atrial fibrillation cardioversion following acupuncture.

    PubMed

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

    2015-11-01

    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

  12. 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

  13. [Electrocardiographic aspects of atrial fibrillations].

    PubMed

    Motté, G; Dinanian, S; Sebag, C

    1995-01-01

    The electrocardiographic analysis of atrial fibrillation is usually easy. However, some cases may be difficult to interpret: the organisation and voltage of the fibrillation waves can be very variable leading to appearances of atypical flutter in cases with large "f" waves or, conversely, in cases with low voltage fibrillation, to those of sinus mode dysfunction. The ventricular response may be slow: the conduction is usually delayed in the atrioventricular node where concealed conduction plays an important role in determining the ventricular response. Regular ventriculogrammes correspond to a junctional or ventricular escape rhythms. Aberrant conduction in the His-Purkinje system may sometimes be observed after long diastoles (phase 4 block) but often terminates short, preceded by long cycles (phase 3 block). It is usually easy to differentiate them from ventricular ectopics or preexcitation by careful examination and application of classical diagnostic criteria. PMID:7786147

  14. Spontaneous onset of atrial fibrillation

    NASA Astrophysics Data System (ADS)

    Zemlin, Christian W.; Mitrea, Bogdan G.; Pertsov, Arkady M.

    2009-06-01

    Most commonly, atrial fibrillation is triggered by rapid bursts of electrical impulses originating in the myocardial sleeves of pulmonary veins (PVs). However, the nature of such bursts remains poorly understood. Here, we propose a mechanism of bursting consistent with the extensive empirical information about the electrophysiology of the PVs. The mechanism is essentially non-local and involves the spontaneous initiation of non-sustained spiral waves in the distal end of the muscle sleeves of the PVs. It reproduces the experimentally observed dynamics of the bursts, including their frequency, their intermittent character, and the unusual shape of the electrical signals in the pulmonary veins that are reminiscent of so-called early afterdepolarizations (EADs).

  15. Present concepts in management of atrial fibrillation: From drug therapy to ablation

    PubMed Central

    Forleo, Giovanni B; Santini, Luca; Romeo, Francesco

    2009-01-01

    Atrial fibrillation (AF) management requires knowledge of its pattern of presentation, underlying conditions, and decisions about restoration and maintenance of sinus rhythm, control of the ventricular rate, and anti-thrombotic therapy. Maintenance of sinus rhythm is a desirable goal in AF patients because the prevention of recurrence may improve cardiac function, relieve symptoms and reduce the likelihood of adverse events. Anti-arrhythmic drug therapy is the first-line treatment for patients with paroxysmal and persistent AF based on current guidelines. However, currently used drugs have limited efficacy and cause cardiac and extracardiac toxicity. Thus, there is a continued need to develop new drugs, device and ablative approaches to rhythm management. Additionally, simpler and safer stroke prevention regimens are needed for AF patients on life-long anticoagulation, including occlusion of the left atrial appendage. The results of the Randomized Evaluation of Long-Term Anticoagulant Therapy study are encouraging in these settings. Knowledge on the pathophysiology of AF is rapidly expanding and identification of focally localized triggers has led to the development of new treatment options for this arrhythmia. Conversely, the clinical decision whether to restore and maintain sinus rhythm or simply control the ventricular rate has remained a matter of intense debate. In the minority of patients in whom AF cannot be adequately managed by pharmacological therapy, the most appropriate type of non-pharmacological therapy must be selected on an individualized basis. Curative treatment of AF with catheter ablation is now a legitimate option for a large number of patients. The evolution of hybrid therapy, in which two or more different strategies are employed in the same patient, may be an effective approach to management of AF. In any case, planning a treatment regimen for AF should include evaluation of the risks inherent in the use of various drugs as well as more

  16. Contained Ascending Aortic Rupture Disguised as a Right Atrial Mass

    PubMed Central

    Marzolino, Philip S.; Reynolds, Justin H.; Coselli, Joseph S.; Grigore, Alina M.

    2008-01-01

    Transesophageal echocardiography can incidentally detect cardiac masses. A right atrial mass has many possible causes, including metastatic extension from various solid organs, malignant melanoma, mediastinal cysts, hematoma, myxoma, lipoma, and artifact. Herein, we report our discovery of a right atrial mass during the initial intraoperative transesophageal echocardiographic examination of a patient who was undergoing repair of an ascending aortic aneurysm. The mass, with a smooth border and homogenous grayscale density, showed no flow during color-flow Doppler echocardiography. Further examination revealed tricuspid annular dilation and severe tricuspid insufficiency. When the mediastinum was opened, we found a large extracardiac hematoma along the right atrium within the pericardial space. These findings suggested an acute, contained rupture of the ascending aorta. After the hematoma was evacuated, imaging revealed complete resolution of the mass and reduction of tricuspid insufficiency. The patient underwent the scheduled aortic repair and was discharged from the hospital in good condition. In order to ensure an accurate diagnosis and to gain appropriate clinical guidance that can lead to a successful outcome, we suggest performing a thorough echocardiographic investigation to identify any such mass before planned surgery proceeds. PMID:18427651

  17. 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

  18. 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

  19. Noninvasive electrocardiomapping facilitates previously failed ablation of right appendage diverticulum associated life-threatening accessory pathway.

    PubMed

    Hocini, Mélèze; Shah, Ashok J; Cochet, Hubert; Maury, Philippe; Denis, Arnaud; Haïssaguerre, Michel

    2013-05-01

    Combination of structural (CT-scan) and functional (3D electrocardiomapping) imaging methods helped successfully accomplish ablation of a life-threatening manifest accessory pathway in association with a complex right atrial anomaly after previous unsuccessful attempts of endo-epicardial ablation guided by the invasive electroanatomic system in an adolescent female. Such a system has a potential to facilitate the ablation procedure and impact its outcome through accurate localization of the arrhythmogenic substrate. PMID:23252769

  20. 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...

  1. 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.

  2. 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. PMID:27140601

  3. 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

  4. Dynamics of a heaving flexible foil in a uniform flow

    NASA Astrophysics Data System (ADS)

    Paraz, Florine; Eloy, Christophe; Schouveiler, Lionel

    2012-11-01

    Most aerial and aquatic animals produce thrust using flapping flexible appendages. The performances of such propulsion systems are strongly related to the appendages dynamics, in particular to the amplitude of the trailing edge motion and to the vortical patterns produced. A better understanding of this mode of propulsion requires to investigate the dynamics of the flexible appendages, as a response to harmonic forcing. In this context, experiments are performed with flexible foils immersed in the uniform flow of a water channel. A harmonic heaving motion, that is transverse to the foil, is then imposed to its leading edge. The response of the foil likely results from the resonance between the forcing and the natural modes of vibration. Experimental results are compared with a two-dimensional model assuming a zero-thickness flexible sheet of infinite span immersed in a potential flow.

  5. Rapid Divergence of Nesting Depth and Digging Appendages among Tunneling Dung Beetle Populations and Species.

    PubMed

    Macagno, Anna L M; Moczek, Armin P; Pizzo, Astrid

    2016-05-01

    Many dung beetle communities are characterized by species that share very similar morphological, ecological, and behavioral traits and requirements yet appear to be stably maintained. Here, we document that the morphologically nearly indistinguishable, sympatric, and syntopic tunneling sister species Onthophagus taurus and Onthophagus illyricus may be avoiding competitive exclusion by nesting at remarkably different soil depths. Intriguingly, we also find rapid divergence in preferred nesting depth across native and recently established O. taurus populations. Furthermore, geometric morphometric analyses reveal that both inter- and intraspecific divergences in nesting depth are paralleled by similar changes in the shape of the primary digging appendages, the fore tibiae. Collectively, our results identify preferred nesting depth and tibial shape as surprisingly evolutionarily labile and with the potential to ease interspecific competition and/or to facilitate adaptation to local climatic conditions. PMID:27105002

  6. The design and development of a spacecraft appendage tie down mechanism

    NASA Technical Reports Server (NTRS)

    Nygren, W. D.; Head, R.

    1985-01-01

    The design and evolution is described of a spacecraft Appendage Tie Down Mechanism (ATDM). Particular emphasis is paid to the mechanical aspects of using dry lubricants to increase the efficiency of acme threads and worm gearing. The ATDM consists of five major components. These are a dc torque motor, a worm gear speed reducer, the tension bolt (or T-bolt), nut capture and centering jaws and the capture nut. In addition, there are several minor components such as limit switch assemblies and an antibackdrive mechanism which couples the drive motor to the worm shaft. A development model of the ATDM in various configurations was under test for some time. In its latest version, it has successfully completed thermal vacuum testing, vibration testing, and extended life testing.

  7. The role of integrins in the development and homeostasis of the epidermis and skin appendages.

    PubMed

    Rippa, A L; Vorotelyak, E A; Vasiliev, A V; Terskikh, V V

    2013-10-01

    Integrins play a critical role in the regulation of adhesion, migration, proliferation, and differentiation of cells. Because of the variety of the functions they play in the cell, they are necessary for the formation and maintenance of tissue structure integrity. The trove of data accumulated by researchers suggests that integrins participate in the morphogenesis of the epidermis and its appendages. The development of mice with tissue-specific integrin genes knockout and determination of the genetic basis for a number of skin diseases in humans showed the significance of integrins in the biology, physiology, and morphogenesis of the epidermis and hair follicles. This review discusses the data on the role of different classes of integrin receptors in the biology of epidermal cells, as well as the development of the epidermis and hair follicles. PMID:24455180

  8. 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.

  9. 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. PMID:27095494

  10. The Role of Integrins in the Development and Homeostasis of the Epidermis and Skin Appendages

    PubMed Central

    Rippa, A.L.; Vorotelyak, E.A.; Vasiliev, A.V.; Terskikh, V.V.

    2013-01-01

    Integrins play a critical role in the regulation of adhesion, migration, proliferation, and differentiation of cells. Because of the variety of the functions they play in the cell, they are necessary for the formation and maintenance of tissue structure integrity. The trove of data accumulated by researchers suggests that integrins participate in the morphogenesis of the epidermis and its appendages. The development of mice with tissue-specific integrin genes knockout and determination of the genetic basis for a number of skin diseases in humans showed the significance of integrins in the biology, physiology, and morphogenesis of the epidermis and hair follicles. This review discusses the data on the role of different classes of integrin receptors in the biology of epidermal cells, as well as the development of the epidermis and hair follicles. PMID:24455180

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

    PubMed

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

    2014-11-01

    Similar predisposing factors are found in most types of atrial arrhythmias. The incidence of atrial fibrillation (AF) among patients with atrial flutter is high, suggesting similar outcomes in patients with those arrhythmias. We sought to investigate the long-term outcomes and prognostic factors of patients with AF and/or atrial flutter with contemporary management using radiofrequency ablation. In an academic institution, we retrospectively examined the clinical course of 8,962 consecutive patients admitted to our department with a diagnosis of AF and/or atrial flutter. After a median follow-up of 934 ± 1,134 days, 1,155 deaths and 715 stroke and/thromboembolic (TE) events were recorded. Patients with atrial flutter undergoing cavotricuspid isthmus ablation (n = 875, 37% with a history of AF) had a better survival rate than other patients (hazard ratio [HR] 0.35, 95% confidence interval [CI] 0.25 to 0.49, p <0.0001). Using Cox proportional hazards model and propensity score model, after adjustment for main other confounders, ablation for atrial flutter was significantly associated with a lower risk of all-cause mortality (HR 0.55, 95% CI 0.36 to 0.84, p = 0.006) and stroke and/or TE events (HR 0.53, 95% CI 0.30 to 0.92, p = 0.02). After ablation, there was no significant difference in the risk of TE between patients with a history of AF and those with atrial flutter alone (HR 0.83, 95% CI 0.41 to 1.67, p = 0.59). In conclusion, in patients with atrial tachyarrhythmias, those with atrial flutter with contemporary management who undergo cavotricuspid isthmus radiofrequency ablation independently have a lower risk of stroke and/or TE events and death of any cause, whether a history of AF is present or not. PMID:25200340

  12. Internal receptors in insect appendages project directly into a special brain neuropile

    PubMed Central

    2013-01-01

    Background The great majority of afferent neurons of insect legs project into their segmental ganglion. Intersegmental projections are rare and are only formed by sense organs associated with the basal joints of the legs. Such intersegmental projections never ascend as far as the brain and they form extensive ramifications within thoracic ganglia. A few afferents of chordotonal organs of the subcoxal joints ascend as far as the suboesophageal ganglion. Results We describe novel afferent neurons in distal segments of locust legs that project directly into the brain without forming ramifications in other ganglia. In the brain, the fibres terminate with characteristic terminals in a small neuropile previously named the superficial ventral inferior protocerebrum. The somata of these neurons are located in the tibiae and tarsi of all legs and they are located within branches of peripheral nerves, or closely associated with such branches. They are not associated with any accessory structures such as tendons or connective tissue strands as typical for insect internal mechanoreceptors such as chordotonal organs or stretch receptors. Morphologically they show great similarity to certain insect infrared receptors. We could not observe projections into the superficial ventral inferior protocerebrum after staining mandibular or labial nerves, but we confirm previous studies that showed projections into the same brain neuropile after staining maxillary and antennal nerves, indicating that most likely similar neurons are present in these appendages also. Conclusion Because of their location deep within the lumen of appendages the function of these neurons as infrared receptors is unlikely. Their projection pattern and other morphological features indicate that the neurons convey information about an internal physiological parameter directly into a special brain neuropile. We discuss their possible function as thermoreceptors. PMID:24015902

  13. A sexually dimorphic corolla appendage affects pollen removal and floral longevity in gynodioecious Cyananthus delavayi (Campanulaceae).

    PubMed

    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

  14. 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.

  15. 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

  16. 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

  17. 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. PMID:22272287

  18. 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

  19. The architecture of the anterior appendage in the egg of the assassin bug, Zelus longipes (Hemiptera: Reduviidae).

    PubMed

    Wolf, K W; Reid, W

    2000-01-01

    The eggshell of Zelus longipes, a Hemiptera species of the family Reduviidae (assassin bugs), has been studied using Scanning Electron Microscopy (SEM). The emphasis was on the architecture of an anterior appendage connected to the main eggshell of both ovarian and deposited eggs. The analysis of eggs fractured at various angles and levels reveals a relatively complex organization of this appendage. There is a cylindrical outer layer, the veil, of roughly the same diameter as, and continuous with, the main eggshell. At its anterior pole, the veil folds inwards and forms an hourglass-shaped tube that is attached through slender extensions to a curved plate oriented at right angles to the long axis of the egg and spanning the internal diameter of the veil. The plate is solid at the center, shows honeycomb-shaped perforations in its mid-section and contains a very delicate meshwork along its circumference. Underneath the plate lies a hollow cylinder oriented at right angles to the long axis of the egg and attached to the anterior plate of the egg, the operculum. The outer openings of aeropyles lie at the inner face of the veil and at its base. While the outer surface of the entire eggshell appears smooth, the inner face of the anterior appendage is highly and diversely sculptured. The eggs are deposited in batches of at least 15 and completely surrounded by viscous secretion. This substance does not encroach on the anterior appendage. The major function of this appendage may lie in the protection of the aeropyles and particularly in preventing their being clogged by the viscous material. PMID:18088938

  20. Continuous recording of coronary sinus oxygen saturation during atrial pacing in patients with coronary artery disease or with syndrome X.

    PubMed Central

    Crake, T; Canepa-Anson, R; Shapiro, L; Poole-Wilson, P A

    1988-01-01

    Coronary sinus oxygen saturation was measured continuously during incremental atrial pacing in 34 patients undergoing cardiac catheterisation. In eleven patients with normal coronary arteriograms, negative exercise tests, and no ST segment depression on the electrocardiogram, an increase in the rate of atrial pacing transiently decreased coronary sinus oxygen saturation but within 20 s oxygen saturation returned to the control value. In six patients with coronary artery disease ST segment depression developed during atrial pacing. The coronary sinus oxygen saturation fell and remained reduced until pacing was discontinued. The size of the fall of coronary sinus oxygen saturation increased with increasing heart rate. In seven patients with coronary artery disease the ST segments were unaltered during atrial pacing and coronary sinus oxygen saturation did not fall. Ten patients with syndrome X were studied. In six ST segment depression developed on atrial pacing. In five, three of whom developed ST segment depression, the changes in coronary sinus oxygen saturation during atrial pacing were similar to those observed in patients without any evidence of coronary artery disease. In three, all of whom developed ST segment depression, coronary sinus oxygen saturation gradually increased throughout the period of atrial pacing. In two patients coronary sinus oxygen saturation fell in a manner similar to that observed in patients with obstructive coronary artery disease who developed ST segment depression on pacing. Thus regulation of coronary blood flow in normal persons in response to an increase of heart rate is rapid. Oxygen extraction across the coronary bed can increase by up to 30% and a persistent increase in oxygen extraction is an indicator of myocardial ischaemia. The term "syndrome X" does not describe a homogeneous group of patients but in the majority coronary sinus oxygen saturation does not fall despite symptoms and changes on the electrocardiogram

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

    MedlinePlus

    ... from the NHLBI on Twitter. What Are the Signs and Symptoms of Atrial Fibrillation? Atrial fibrillation (AF) ... the lungs and body. This can lead to signs and symptoms, such as: Palpitations (feelings that your ...

  2. 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

  3. 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

  4. A Case of Giant Right Atrial Aneurysm in a Child.

    PubMed

    Pawar, Ravindra S; Tiwari, Ashish; Suresh, P V; Raj, Vimal; Kaushik, Pradeepkumar

    2016-07-01

    Giant right atrial aneurysm is a rare entity in infants and children. It needs to be distinguished from an atrial diverticulum, which can have similar presentation. Generally, an incidental finding in children, it can present with varied symptoms. We report a case of a giant right atrial aneurysm in an asymptomatic child with a large clot in the dilated right atrium, who underwent successful resection of the atrial aneurysm. PMID:26884450

  5. Atrial myocardial infarction: A tale of the forgotten chamber.

    PubMed

    Lu, Marvin Louis Roy; De Venecia, Toni; Patnaik, Soumya; Figueredo, Vincent M

    2016-01-01

    It has been almost a century since atrial infarction was first described, yet data describing its significance remain limited. To date, there are still no universally accepted criteria for the diagnosis of atrial infarction. Atherosclerosis is the leading cause of atrial infarction but it has also been described in cor pulmonale and pulmonary hypertension. Atrial infarction almost always occurs concomitantly with ventricular infarction. Its clinical presentation depends largely on the extent and site of ventricular involvement. Atrial infarction can present with supraventricular tachyarrhythmias. Electrocardiographic (ECG) criteria for diagnosing atrial infarction have been described but none have yet to be validated by prospective studies. Atrial ECG patterns include abnormal P-wave morphologies, PR-segment deviations, as well as transient rhythm abnormalities, including atrial fibrillation, atrial flutter, atrial tachycardia, wandering atrial pacemaker (WAP) and atrioventricular (AV) blocks. Complications of atrial infarction include thromboembolic events and cardiogenic shock. There are no specific additional recommendations in the management of myocardial infarction with suspected involvement of the atria. The primary goal remains coronary reperfusion and maintenance of, or conversion to, sinus rhythm. PMID:26485186

  6. [Development of an electrode for atrial epicardial mapping].

    PubMed

    Tan, C; Zheng, Q; Du, R

    1998-01-01

    Procedure of a electrode for atrial epicardial mapping (template electrode) is introduced in this paper. It is easy to made, we can get sharp and clear waveforms and a constant baseline while mapping. If the electrode is connected with computer, it is able to be used for epicardial mapping of atrial arrhythmias, especially atrial fibrillation in real time. PMID:12016844

  7. Atrial Fibrillation Complications | NIH MedlinePlus the Magazine

    MedlinePlus

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

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

    MedlinePlus

    ... Pressure Tools & Resources Stroke More Treatment Guidelines of Atrial Fibrillation (AFib or AF) Updated:Jun 23,2016 What ... content was last reviewed on 04/16/14. Atrial Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters • ...

  9. 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

  10. 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

  11. Atrial fibrillation from the pathologist's perspective.

    PubMed

    Corradi, Domenico

    2014-01-01

    Atrial fibrillation (AF), the most common sustained cardiac arrhythmia encountered in clinical practice, is associated with increased morbidity and mortality. Electrophysiologically, it is characterized by a high rate of asynchronous atrial cell depolarization causing a loss of atrial contractile function and irregular ventricular rates. For a long time, AF was considered as a pure functional disorder without any structural background. Only in recent years, have new mapping and imaging techniques identified atrial locations, which are very often involved in the initiation and maintenance of this supraventricular arrhythmia (i.e. the distal portion of the pulmonary veins and the surrounding atrial myocardium). Morphological analysis of these myocardial sites has demonstrated significant structural remodeling as well as paved the way for further knowledge of AF natural history, pathogenesis, and treatment. This architectural myocardial disarrangement is induced by the arrhythmia itself and the very frequently associated cardiovascular disorders. At the same time, the structural remodeling is also capable of sustaining AF, thereby creating a sort of pathogenetic vicious circle. This review focuses on current understanding about the structural and genetic bases of AF with reference to their classification, pathogenesis, and clinical implications. PMID:24462196

  12. 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.

  13. [Antithrombotic management in atrial fibrillation].

    PubMed

    Fauchier, Laurent; Taillandier, Sophie; Clementy, Nicolas

    2013-02-01

    There is increasing recognition of the value of oral anticoagulation for stroke prevention in atrial fibrillation (AF), and the availability of new oral anticoagulants that overcome the limitations of vitamin K antagonists (VKA). Stroke risk assessment using the CHA2DS2-Vasc score allows identification of patients who are at truly low risk (score = 0) who should need no antithrombotic therapy, while all others (CHA2DS2-Vasc score > or = 1 with a risk of thromboembolic event > 1% per year) would be considered for oral anticoagulation. The HAS-BLED score has been recently proposed to easily assess bleeding risk in AF patients. A score of > or = 3 indicates "high risk" and some caution and regular review of the patient are needed. It also makes the clinician think of correctable common bleeding risk factors. The direct thrombin inhibitor dabigatran and factor Xa inhibitors rivaroxaban and apixaban are new oral anticoagulants that are at least as efficacious and safe as VKA in non valvular AF. Their advantages are easier use, predictable anticoagulant effects, low propensity for food and drug interactions, and lower rates of intracranial bleeding than with VKA, but they should not be used in patients with kidney disease at the present time. Overall, one may expect that more AF patients will be appropriately treated with oral anticoagulation in the next years. PMID:23513780

  14. 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.

  15. 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.

  16. 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...

  17. [Persistent atrial paralysis: reported of 2 cases].

    PubMed

    Rodríguez Reyes, H; Cruz Cruz, F; Iturralde Torres, P; de Micheli, A; González Hermosillo, J A

    1997-01-01

    Persistent atrial standstill is an uncommon clinical finding, this condition has no atrial electrical activity and do not respond to electrical stimulation. Electrophysiologic mapping of the heart, demonstrates two types of standstill: total and partial. There are three types of patients with this condition: patients with chronic cardiopathy, patients with muscular dystrophy and the third idiopathic group. In this article, we present two clinical cases, the fist one with dilated cardiomiopathy, in which we demonstrated total atrial standstill. The second patient with rheumatic heart disease, in which we demonstrated partial standstill that included the apical portion of the rigth atrium. We discuss the clinical and electrophysiological finding of both cases and we review the literature. PMID:9585833

  18. Platelet Reactivity Is Independent of Left Atrial Wall Deformation in Patients with Atrial Fibrillation.

    PubMed

    Procter, Nathan; Goh, Vincent; Mahadevan, Gnanadevan; Stewart, Simon; Horowitz, John

    2016-01-01

    It has been documented recently that left atrial (LA) deformation in AF patients (while in AF) is predictive of subsequent stroke risk. Additionally, diminished LA deformation during AF correlates with the presence of LA blood stasis. Given that endothelial function is dependent on laminar blood flow, the present study sought to investigate the effect of diminished LA deformation (during AF) on platelet reactivity and inflammation in AF patients. Patients (n = 17) hospitalised with AF underwent echocardiography (while in AF) for determination of peak positive LA strain (LASp). Whole blood impedance aggregometry was used to measure extent of ADP-induced aggregation and subsequent inhibitory response to the nitric oxide (NO) donor, sodium nitroprusside. Platelet thioredoxin-interacting protein (Txnip) content was determined by immunohistochemistry. LASp tended (p = 0.078) to vary inversely with CHA2DS2VASc scores. However, mediators of inflammation (C-reactive protein, Txnip) did not correlate significantly with LASp nor did extent of ADP-induced platelet aggregation or platelet NO response. These results suggest that the thrombogenic risk associated with LA stasis is independent of secondary effects on platelet aggregability or inflammation. PMID:27069318

  19. Platelet Reactivity Is Independent of Left Atrial Wall Deformation in Patients with Atrial Fibrillation

    PubMed Central

    Procter, Nathan; Goh, Vincent; Mahadevan, Gnanadevan; Stewart, Simon; Horowitz, John

    2016-01-01

    It has been documented recently that left atrial (LA) deformation in AF patients (while in AF) is predictive of subsequent stroke risk. Additionally, diminished LA deformation during AF correlates with the presence of LA blood stasis. Given that endothelial function is dependent on laminar blood flow, the present study sought to investigate the effect of diminished LA deformation (during AF) on platelet reactivity and inflammation in AF patients. Patients (n = 17) hospitalised with AF underwent echocardiography (while in AF) for determination of peak positive LA strain (LASp). Whole blood impedance aggregometry was used to measure extent of ADP-induced aggregation and subsequent inhibitory response to the nitric oxide (NO) donor, sodium nitroprusside. Platelet thioredoxin-interacting protein (Txnip) content was determined by immunohistochemistry. LASp tended (p = 0.078) to vary inversely with CHA2DS2VASc scores. However, mediators of inflammation (C-reactive protein, Txnip) did not correlate significantly with LASp nor did extent of ADP-induced platelet aggregation or platelet NO response. These results suggest that the thrombogenic risk associated with LA stasis is independent of secondary effects on platelet aggregability or inflammation. PMID:27069318

  20. Myeloperoxidase acts as a profibrotic mediator of atrial fibrillation

    PubMed Central

    Rudolph, Volker; Andrié, René P; Rudolph, Tanja K; Friedrichs, Kai; Klinke, Anna; Hirsch-Hoffmann, Birgit; Schwoerer, Alexander P; Lau, Denise; Fu, XiaoMing; Klingel, Karin; Sydow, Karsten; Didié, Michael; Seniuk, Anika; von Leitner, Eike-Christin; Szoecs, Katalin; Schrickel, Jan W; Treede, Hendrik; Wenzel, Ulrich; Lewalter, Thorsten; Nickenig, Georg; Zimmermann, Wolfram-Hubertus; Meinertz, Thomas; Böger, Rainer H; Reichenspurner, Hermann; Freeman, Bruce A; Eschenhagen, Thomas; Ehmke, Heimo; Hazen, Stanley L; Willems, Stephan; Baldus, Stephan

    2010-01-01

    Observational clinical and ex vivo studies have established a strong association between atrial fibrillation and inflammation1. However, whether inflammation is the cause or the consequence of atrial fibrillation and which specific inflammatory mediators may increase the atria's susceptibility to fibrillation remain elusive. Here we provide experimental and clinical evidence for the mechanistic involvement of myeloperoxidase (MPO), a heme enzyme abundantly expressed by neutrophils, in the pathophysiology of atrial fibrillation. MPO-deficient mice pretreated with angiotensin II (AngII) to provoke leukocyte activation showed lower atrial tissue abundance of the MPO product 3-chlorotyrosine, reduced activity of matrix metalloproteinases and blunted atrial fibrosis as compared to wild-type mice. Upon right atrial electrophysiological stimulation, MPO-deficient mice were protected from atrial fibrillation, which was reversed when MPO was restored. Humans with atrial fibrillation had higher plasma concentrations of MPO and a larger MPO burden in right atrial tissue as compared to individuals devoid of atrial fibrillation. In the atria, MPO colocalized with markedly increased formation of 3-chlorotyrosine. Our data demonstrate that MPO is a crucial prerequisite for structural remodeling of the myocardium, leading to an increased vulnerability to atrial fibrillation. PMID:20305660

  1. [Obesity as a risk factor for atrial fibrillation].

    PubMed

    Duraj, Iwona; Broncel, Marlena

    2016-01-01

    Atrial fibrillation (AF) and obesity is a growing problem of public health both in Poland and in the whole world. AF risk factors may be summarized as elderliness, male sex, smoking, hypertension, diabetes, obesity, coronary heart disease, heart failure, valvular heart disease, cardiac surgery. Once obesity is an independent, potentially modifiable risk factor for AF. The connection between obesity and atrial fibrillation is very up-to-date because of incremental prevalence, almost epidemic of obesity in the whole world. The probability of AF among obese patients increases with concomitant obstructive sleep apnea. Regardless many researches it hasn't been assessed yet how obesity itself predisposes to AF. It could be an effect of change in the atrial anatomy, the rise of atrial pressure, mechanical stretch, interstitial atrial fibrosis and disruption of atrial electric integrity. A great role is ascribed to inflammation, especially proinflammatory cytokines increased by adipocites of left atrial epicardial adiposity. PMID:26891428

  2. Single lead atrial synchronous ventricular pacing: a dream come true.

    PubMed

    Antonioli, G E

    1994-09-01

    Single lead, atrial synchronous pacing systems were developed in the late 1970s. Clinical experience has demonstrated the need to position the "floating" atrial electrode in the mid-to-high right atrium and the need for a specially designed pulse generator (with very high atrial sensitivity) to provide a high quality and amplitude atrial electrogram for consistent sensing. A 12-year experience with different electrode configurations, from the first unipolar designed in 1980 to the most recent atrial bipolar electrodes, has confirmed the validity of the original concept and the long-term reliability of the single lead atrial synchronous pacing system, which can reliably produce long-term atrial sensing and ventricular stimulation in the presence of normal sinoatrial function. PMID:7991425

  3. [Total Endoscopic Left Atrial Appendectomy for Valvular Atrial Fibrillation;Report of a Case].

    PubMed

    Kurahashi, Kanan; Inoue, Takafumi; Yoshimoto, Akihiro; Fujisaki, Masayuki; Morisumi, Sei; Ohtsuka, Toshiya; Suematsu, Yoshihiko

    2016-06-01

    Total endoscopic left atrial appendectomy for non-valvular atrial fibrillation(Af) has been reported to be a safe and effective procedure to prevent cardiogenic thromboembolism and also discontinue oral anticoagulant therapy. On the other hand, open-heart surgery is generally indicated for valvular Af. We report the case of a 67-year-old male patient with valvular Af and recurrent episodes of cardiogenic thromboembolism who underwent total endoscopic left atrial appendectomy. He was diagnosed as having mitral valve stenosis and scheduled for surgery, but presented with cerebellar hemorrhage after warfarin was replaced with heparin in the preoperative phase. Consequently, the operation was cancelled. The case was considered as a good relative indication for total endoscopic left atrial appendectomy, which does not need a cardiopulmonary bypass, to prevent future cardiogenic thromboembolism. The operation was performed and the postoperative course was uneventful. PMID:27246134

  4. 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

  5. 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. PMID:24968547

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

    PubMed Central

    Kim, Ha Eun; Jung, Jo Won; Shin, Yu Rim; Park, Han Ki; Park, Young Hwan; Shin, Hong Ju

    2016-01-01

    Patients with venoarterial extracorporeal membrane oxygenation (ECMO) frequently suffer from pulmonary edema due to left ventricular dysfunction that accompanies left heart dilatation, which is caused by left atrial hypertension. The problem can be resolved by left atrium (LA) decompression. We performed a successful percutaneous LA decompression with an atrial septostomy and placement of an LA venting cannula in a 38-month-old child treated with venoarterial ECMO for acute myocarditis. PMID:27298800

  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. Adjusted Left Atrial Emptying Fraction as a Predictor of Procedural Outcome after Catheter Ablation for Atrial Fibrillation

    PubMed Central

    Im, Sung Il; Kim, Sun Won; Choi, Cheol Ung; Kim, Jin Won; Yong, Hwan Seok; Kim, Eung Ju; Rha, Seung-Woon; Park, Chang Gyu; Seo, Hong Seog; Oh, Dong Joo; Lim, Hong Euy

    2015-01-01

    Structural remodeling of the left atrium is a risk factor for recurrent arrhythmia after catheter ablation for atrial fibrillation; however, data are sparse regarding the role of functional left atrial remodeling in predicting procedural outcomes. We evaluated whether left atrial transport function could be used to predict recurrent atrial fibrillation. From July 2008 through August 2010, we enrolled 202 consecutive patients who underwent catheter ablation for atrial fibrillation (paroxysmal=120, persistent=82). Left atrial volumes (LAVs) were measured by means of multislice computed tomography at every 10% of the R-R interval, and measurements were adjusted for body surface area to yield the LAV index (LAVI) at baseline. The left atrial emptying fraction (LAEF) was calculated according to LAV differences. During the mean follow-up period of 10 ± 4 months after a single ablation procedure, atrial fibrillation recurred in 59 patients (paroxysmal=19, persistent=40). Multivariate analysis revealed that persistent atrial fibrillation, early mitral inflow velocity, LAVImax, LAVImin, LAEF, LAVImax/LAEF, and LAVImin/LAEF were all independent predictors of atrial fibrillation, but the best predictor was LAVImin/LAEF (β=1.329, P=0.001). The cutoff value was 1.61 (mL/m2)/%, and the sensitivity and specificity were 74.6% and 62.2%, respectively (area under the curve=0.761). Our study shows that adjusted left atrial emptying fraction with use of multislice computed tomography might be a useful, noninvasive method to select patients for ablation. PMID:26175632

  9. Atrial evoked response integral for automatic capture verification in atrial pacing.

    PubMed

    Boriani, Giuseppe; Biffi, Mauro; Cameron, Douglas; Datteri, Sergio; Snell, Jeff; Holmström, Nils; Park, Euljoon; Bornzin, Gene A

    2003-01-01

    Beat-by-beat Autocapture is currently limited to operation in the ventricle with bipolar leads. The authors investigated the integral of the negative-going portion of the atrial evoked response integral (AERI) as a potential resource for verification of atrial capture. Intracardiac electrogram signals were collected from 59 patients (ages 67.8 +/- 15.1 years) with bipolar, low polarization atrial leads. The signals were collected over a mean period of 6.1 months (minimum 4 days) after lead implantation. St. Jude Medical Affinity pulse generators were used to perform automatic capture threshold tests while the electrogram signals were recorded by a Model 3510 programming device. These signals were transferred to a personal computer in digital form for later analysis. The AERI was calculated at each programmable pacing voltage until capture was lost. The difference between the polarization integral at loss of capture and evoked response integral with successful capture was sufficient to justify enabling the atrial Autocapture feature in 53 of 59 patients in whom bipolar pacing and unipolar sensing was performed. The authors developed a calibration routine to identify automatically those patients in whom atrial Autocapture could be programmed On, based on the polarization integral at loss of capture, the estimated maximum polarization integral, and the AERI. Preliminary analysis indicated that the AERI is a practical resource for beat-by-beat atrial capture detection when used with low polarization leads. PMID:12687822

  10. Assessment of atrial fibrosis for the rhythm control of atrial fibrillation.

    PubMed

    Begg, Gordon A; Holden, Arun V; Lip, Gregory Y H; Plein, Sven; Tayebjee, Muzahir H

    2016-10-01

    Rhythm control of atrial fibrillation (AF) remains challenging, with modest long-term success rates. Atrial fibrosis has been associated with AF, but the clinical utility of assessment of this fibrosis has yet to be fully elucidated. In this paper we review the current state of understanding of the pathophysiology of atrial fibrosis in AF, and its impact upon the instigation and propagation of the arrhythmia. Fibrosis causes an increase in volume of dysfunctional extracellular matrix, and is associated with cellular alterations such as hypertrophy, apoptosis and membrane dysfunction within the atrial myocardium. In turn, these cause pathological alterations to atrial conduction, such as increased anisotropy, conduction block and re-entry, which can lead to AF. We review current methods of assessing atrial fibrosis and their impact upon the prediction of success of interventional rhythm control strategies such as ablation and cardioversion. We focus particularly on circulating biomarkers of fibrosis and scar formation; their role in the fibrotic process, and their value in the prediction of rhythm control success. We also review imaging and invasive electrocardiographic mapping techniques that may identify fibrosis, and again assess their potential predictive value. In this area there exist many unanswered questions, but further work will help to refine techniques to reliably identify and treat those patients who are most likely to benefit from rhythm control treatment strategies. PMID:27389440

  11. 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. PMID:19649305

  12. Prediction of maintenance of sinus rhythm after cardioversion of atrial fibrillation by analysis of serial signal-averaged P waves.

    PubMed

    Stafford, P J; Kamalvand, K; Tan, K; Vincent, R; Sulke, N

    1998-07-01

    After cardioversion from atrial fibrillation (AF) many patients develop early recurrence of the arrhythmia. While these patients may be appropriate for immediate prophylaxis against AF recurrence their identification at the time of cardioversion is not possible. Since the signal-averaged P wave (SAPW) is abnormal in individuals with atrial arrhythmia, we assessed its utility for predicting early AF recurrence after cardioversion. Seventy-five cardioversions in 31 patients were evaluated. The mean age was 59 (range 28-79) years; 26 were male. Fifty-eight cardioversions were internal using low energy biphasic DC shocks delivered via electrodes placed in the right atrial appendage and coronary sinus. P wave specific signal averaging was performed at 3 and 24 hours after each cardioversion to estimate filtered P wave duration and energy from 20, 40, and 60 to 150 Hz. Follow-up was by regular clinic visits and transtelephonic ECG monitoring. Early recurrence of AF (prospectively defined as sinus rhythm duration < 1 week) occurred after 30 cardioversions. No differences were found in any P wave variable measured at 3 hours between these cardioversions and those that resulted in a longer duration of sinus rhythm. Paired 3- and 24-hour signal-averaged data were available in 47 cardioversions. There were significant falls in P wave energy from 3 to 24 hours after 31 cardioversions that resulted in sinus rhythm for > 1 week, (P40: 3 hours 11.2 [+/- 1.5] micro V2.s, 24 hours 8.6 [+/- 1.2] micro V2.s, P < 0.001), but not following the 16 after which AF returned within 1 week (P40: 3 hours 9.0 [+/- 1.2] micro V2.s, 24 hours 8.5 [+/- 1.2 micro V2.s, P = NS). A fall in P40 of > 25% had a positive predictive accuracy for maintenance of sinus rhythm of 87%; negative predictive accuracy was only 37%. Similar falls in P wave energy occurred after cardioversions that resulted in longer term (> 4 weeks) sinus rhythm, but not in those that did not. However, the predictive accuracy of a

  13. The Diagnostic Dilemma of Primary Epiploic Appendagitis and How to Establish a Diagnosis

    PubMed Central

    Gourgiotis, Stavros; Oikonomou, Christianna; Veloudis, George; Lardou, Ioanna; Pittaras, George; Villias, Constantinos

    2016-01-01

    Primary epiploic appendagitis (PEA) is a relatively uncommon, non-surgical situation that clinically mimics other conditions requiring surgery. In PEA, torsion and inflammation of an epiploic appendix results in localized abdominal pain. This condition may be clinically misdiagnosed, resulting in unnecessary surgical intervention. We report the unusual case of a healthy 44-year-old man, who presented to the 417 NIMTS Military Veterans’ Fund Hospital of Athens with non-migratory left lower quadrant abdominal pain, which had started 24 hours before admission. The patient described a constant, sharp, non-radiating pain. He had no symptoms of nausea, vomiting, constipation, diarrhea, or fever. Abdominal examination showed focal abdominal tenderness with slight rebound tenderness. The diagnosis of PEA of the sigmoid colon was made based on the findings of an abdominal contrast computed tomography (CT). The key findings of CT were an oval lesion with a maximum diameter of 2.4 cm, with fat attenuation, and a circumferential hyperdense ring located adjacent to the sigmoid colon. This case is presented to highlight the clinical characteristics of PEA, which may help clinicians to overcome this diagnostic dilemma and reach the correct diagnosis. PMID:27162597

  14. The origins of adipose fins: an analysis of homoplasy and the serial homology of vertebrate appendages.

    PubMed

    Stewart, Thomas A; Smith, W Leo; Coates, Michael I

    2014-04-22

    Adipose fins are appendages found on the dorsal midline between the dorsal and caudal fins in more than 6000 living species of teleost fishes. It has been consistently argued that adipose fins evolved once and have been lost repeatedly across teleosts owing to limited function. Here, we demonstrate that adipose fins originated repeatedly by using phylogenetic and anatomical evidence. This suggests that adipose fins are adaptive, although their function remains undetermined. To test for generalities in the evolution of form in de novo vertebrate fins, we studied the skeletal anatomy of adipose fins across 620 species belonging to 186 genera and 55 families. Adipose fins have repeatedly evolved endoskeletal plates, anterior dermal spines and fin rays. The repeated evolution of fin rays in adipose fins suggests that these fins can evolve new tissue types and increased structural complexity by expressing fin-associated developmental modules in these new territories. Patterns of skeletal elaboration differ between the various occurrences of adipose fins and challenge prevailing hypotheses for vertebrate fin origin. Adipose fins represent a powerful and, thus far, barely studied model for exploring the evolution of vertebrate limbs and the roles of adaptation and generative biases in morphological evolution. PMID:24598422

  15. 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. PMID:25041335

  16. Leptin receptor is expressed by epidermis and skin appendages in dog.

    PubMed

    Mercati, Francesca; Maranesi, Margherita; Dall'Aglio, Cecilia; Scocco, Paola; Pascucci, Luisa; Boiti, Cristiano; Ceccarelli, Piero

    2014-10-01

    Leptin is a polypeptide secreted by adipocytes which binds to a specific receptor (Ob-R) that is expressed in various tissues. The wide distribution of the Ob-R suggests that leptin might exert diverse biological functions, not only by regulating energy metabolism and appetite, but also by acting as a mitogen in many cell types, including keratinocytes. In this study, the presence and localization of Ob-R was investigated in the skin of the dog using RT-PCR and immunohistochemical techniques. RT-PCR revealed the presence of Ob-R m-RNA in the skin specimens collected from the dorsal region of two smooth coat breed dogs. Through immunohistochemistry performed on the skin of five dogs, the expression of the receptor was observed in the basal layer of the epidermis, in the hair follicles as well as in the apocrine sweat and sebaceous glands. No staining for Ob-R was detected in the suprabasal epidermis layers. Strong positive signals were observed in many cells of the outer root sheath of hair follicles in growing and in regressive phases. The identification of Ob-R in the above targets suggests that leptin may play a role in the regulation of cyclic renewal of the epidermis and skin appendages in dog. This study represents an important contribution to understand the complex mechanisms that are involved in the skin biology in this species. PMID:25131155

  17. Localization of 'Candidatus Liberibacter solanacearum' and Evidence for Surface Appendages in the Potato Psyllid Vector.

    PubMed

    Cicero, J M; Fisher, T W; Brown, J K

    2016-02-01

    The potato psyllid Bactericera cockerelli is implicated as the vector of the causal agent of zebra chip of potato and vein-greening of tomato diseases. Until now, visual identification of bacteria in the genus 'Candidatus Liberibacter' has relied on direct imaging by light and electron microscopy without labeling, or with whole-organ fluorescence labeling only. In this study, aldehyde fixative followed by a coagulant fixative, was used to process adult psyllids for transmission electron microscopy (TEM) colloidal gold in situ hybridization experiments. Results indicated that 'Ca. Liberibacter solanacearum' (CLso)-specific DNA probes annealed to a bacterium that formed extensive, monocultural biofilms on gut, salivary gland, and oral region tissues, confirming that it is one morphotype of potentially others, that is rod-shaped, approximately 2.5 µm in diameter and of variable length, and has a rough, granular cytosol. In addition, CLso, prepared from shredded midguts, and negatively stained for TEM, possessed pili- and flagella-like surface appendages. Genes implicating coding capacity for both types of surface structures are encoded in the CLso genome sequence. Neither type was seen for CLso associated with biofilms within or on digestive organs, suggesting that their production is stimulated only in certain environments, putatively, in the gut during adhesion leading to multiplication, and in hemolymph to afford systemic invasion. PMID:26551449

  18. The Diagnostic Dilemma of Primary Epiploic Appendagitis and How to Establish a Diagnosis.

    PubMed

    Gourgiotis, Stavros; Oikonomou, Christianna; Veloudis, George; Lardou, Ioanna; Pittaras, George; Villias, Constantinos

    2016-05-01

    Primary epiploic appendagitis (PEA) is a relatively uncommon, non-surgical situation that clinically mimics other conditions requiring surgery. In PEA, torsion and inflammation of an epiploic appendix results in localized abdominal pain. This condition may be clinically misdiagnosed, resulting in unnecessary surgical intervention. We report the unusual case of a healthy 44-year-old man, who presented to the 417 NIMTS Military Veterans' Fund Hospital of Athens with non-migratory left lower quadrant abdominal pain, which had started 24 hours before admission. The patient described a constant, sharp, non-radiating pain. He had no symptoms of nausea, vomiting, constipation, diarrhea, or fever. Abdominal examination showed focal abdominal tenderness with slight rebound tenderness. The diagnosis of PEA of the sigmoid colon was made based on the findings of an abdominal contrast computed tomography (CT). The key findings of CT were an oval lesion with a maximum diameter of 2.4 cm, with fat attenuation, and a circumferential hyperdense ring located adjacent to the sigmoid colon. This case is presented to highlight the clinical characteristics of PEA, which may help clinicians to overcome this diagnostic dilemma and reach the correct diagnosis. PMID:27162597

  19. 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

  20. 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. PMID:15939417

  1. 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

  2. Idiopathic Aortic Root to Right Atrial Fistula.

    PubMed

    Campisi, Salvatore; Cluzel, Armand; Vola, Marco; Fuzellier, Jean Francois

    2016-06-01

    An aorta to right atrium fistula is rare. We report a case of idiopathic aortic root to right atrial fistula with right heart failure and review the literature. doi: 10.1111/jocs.12751 (J Card Surg 2016;31:373-375). PMID:27109166

  3. Noninvasive mapping to guide atrial fibrillation ablation.

    PubMed

    Lim, Han S; Zellerhoff, Stephan; Derval, Nicolas; Denis, Arnaud; Yamashita, Seigo; Berte, Benjamin; Mahida, Saagar; Hooks, Darren; Aljefairi, Nora; Shah, Ashok J; Sacher, Frédéric; Hocini, Meleze; Jais, Pierre; Haissaguerre, Michel

    2015-03-01

    Atrial fibrillation (AF) is a dynamic rhythm. Noninvasive mapping overcomes many previous barriers to mapping such a dynamic rhythm, by providing a beat-to-beat, biatrial, panoramic view of the AF process. Catheter ablation of AF drivers guided by noninvasive mapping has yielded promising clinical results and has advanced understanding of the underlying pathophysiologic processes of this common heart rhythm disorder. PMID:25784025

  4. Epicardial adipose tissue and atrial fibrillation.

    PubMed

    Hatem, Stéphane N; Sanders, Prashanthan

    2014-05-01

    Atrial fibrillation (AF) is the most frequent cardiac arrhythmia in clinical practice. AF is often associated with profound functional and structural alterations of the atrial myocardium that compose its substrate. Recently, a relationship between the thickness of epicardial adipose tissue (EAT) and the incidence and severity of AF has been reported. Adipose tissue is a biologically active organ regulating the metabolism of neighbouring organs. It is also a major source of cytokines. In the heart, EAT is contiguous with the myocardium without fascia boundaries resulting in paracrine effects through the release of adipokines. Indeed, Activin A, which is produced in abundance by EAT during heart failure or diabetes, shows a marked fibrotic effect on the atrial myocardium. The infiltration of adipocytes into the atrial myocardium could also disorganize the depolarization wave front favouring micro re-entry circuits and local conduction block. Finally, EAT contains progenitor cells in abundance and therefore could be a source of myofibroblasts producing extracellular matrix. The study on the role played by adipose tissue in the pathogenesis of AF is just starting and is highly likely to uncover new biomarkers and therapeutic targets for AF. PMID:24648445

  5. 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

  6. Wandering atrial pacemaker (prevalence in French hornists).

    PubMed

    Nizet, P M; Borgi, J F; Horvath, S M

    1976-01-01

    Continuous electrocardiographic recordings were obtained in a group of French horn players during performance of identical pieces of music. Half of the musicians developed wandering atrial pacemaker. One example is illustrated. The causative mechanism is briefly discussed. This may represent an "occupational" hazard. PMID:1245812

  7. Quantification of left to right shunt in atrial septal defect using systolic time intervals derived from pulsed Doppler velocimetry.

    PubMed Central

    Veyrat, C; Gourtchiglouian, C; Bas, S; Abitbol, G; Kalmanson, D

    1984-01-01

    Systolic time intervals derived from Doppler velocimetry measurements were used instead of direct pulmonary to systemic flow ratio measurements in adults with atrial septal defect to quantify left to right atrial shunts. Thirteen normal subjects and 25 patients with uncomplicated atrial septal defect confirmed by cardiac catheterisation were studied. The pulmonary to systemic flow ratio (Qp:Qs) expressing the shunt size was determined by the Fick method; in normal subjects the Qp:Qs ratio was assumed to be equal to 1.0. The pulsed Doppler analogue velocity recording of flow in the pulmonary artery and the ascending aorta was taken as indicating the ejection time of each ventricle and the Q wave of the electrocardiogram as indicating the onset of systole. From these measurements the ratios of the pre-ejection periods to the ejection times (haemodynamic ratio) were calculated for each ventricle and the ratios of each variable (pre-ejection period, ejection time, and haemodynamic ratio) were calculated for both ventricles. Significant differences were found between the normal subjects and the patients with atrial septal defect for all these ratios. When the Doppler findings and the Fick measurements of Qp:Qs were compared the best linear correlation coefficient was for the left to right haemodynamic ratio. It is concluded that the use of a ratio involving several variables, such as the pre-ejection period and the ejection time for both ventricles, improves the reliability of this method, which appears to be applicable in adults. Images PMID:6239641

  8. The effects of the Cox maze procedure on atrial function

    PubMed Central

    Voeller, Rochus K.; Zierer, Andreas; Lall, Shelly C.; Sakamoto, Shun–ichiro; Chang, Nai–Lun; Schuessler, Richard B.; Moon, Marc R.; Damiano, Ralph J.

    2010-01-01

    Objective The effects of the Cox maze procedure on atrial function remain poorly defined. The purpose of this study was to investigate the effects of a modified Cox maze procedure on left and right atrial function in a porcine model. Methods After cardiac magnetic resonance imaging, 6 pigs underwent pericardiotomy (sham group), and 6 pigs underwent a modified Cox maze procedure (maze group) with bipolar radiofrequency ablation. The maze group had preablation and immediate postablation left and right atrial pressure–volume relations measured with conductance catheters. All pigs survived for 30 days. Magnetic resonance imaging was then repeated for both groups, and conductance catheter measurements were repeated for the right atrium in the maze group. Results Both groups had significantly higher left atrial volumes postoperatively. Magnetic resonance imaging–derived reservoir and booster pump functional parameters were reduced postoperatively for both groups, but there was no difference in these parameters between the groups. The maze group had significantly higher reduction in the medial and lateral left atrial wall contraction postoperatively. There was no change in immediate left atrial elastance or in the early and 30-day right atrial elastance after the Cox maze procedure. Although the initial left atrial stiffness increased after ablation, right atrial diastolic stiffness did not change initially or at 30 days. Conclusions Performing a pericardiotomy alone had a significant effect on atrial function that can be quantified by means of magnetic resonance imaging. The effects of the Cox maze procedure on left atrial function could only be detected by analyzing segmental wall motion. Understanding the precise physiologic effects of the Cox maze procedure on atrial function will help in developing less-damaging lesion sets for the surgical treatment of atrial fibrillation. PMID:19026812

  9. How to define valvular atrial fibrillation?

    PubMed

    Fauchier, Laurent; Philippart, Raphael; Clementy, Nicolas; Bourguignon, Thierry; Angoulvant, Denis; Ivanes, Fabrice; Babuty, Dominique; Bernard, Anne

    2015-10-01

    Atrial fibrillation (AF) confers a substantial risk of stroke. Recent trials comparing vitamin K antagonists (VKAs) with non-vitamin K antagonist oral anticoagulants (NOACs) in AF were performed among patients with so-called "non-valvular" AF. The distinction between "valvular" and "non-valvular" AF remains a matter of debate. Currently, "valvular AF" refers to patients with mitral stenosis or artificial heart valves (and valve repair in North American guidelines only), and should be treated with VKAs. Valvular heart diseases, such as mitral regurgitation, aortic stenosis (AS) and aortic insufficiency, do not result in conditions of low flow in the left atrium, and do not apparently increase the risk of thromboembolism brought by AF. Post-hoc analyses suggest that these conditions probably do not make the thromboembolic risk less responsive to NOACs compared with most forms of "non-valvular" AF. The pathogenesis of thrombosis is probably different for blood coming into contact with a mechanical prosthetic valve compared with what occurs in most other forms of AF. This may explain the results of the only trial performed with a NOAC in patients with a mechanical prosthetic valve (only a few of whom had AF), where warfarin was more effective and safer than dabigatran. By contrast, AF in the presence of a bioprosthetic heart valve or after valve repair appears to have a risk of thromboembolism that is not markedly different from other forms of "non-valvular" AF. Obviously, we should no longer consider the classification of AF as "valvular" (or not) for the purpose of defining the aetiology of the arrhythmia, but for the determination of a different risk of thromboembolic events and the need for a specific antithrombotic strategy. As long as there is no better new term or widely accepted definition, "valvular AF" refers to patients with mitral stenosis or artificial heart valves. Patients with "non-valvular AF" may have other types of valvular heart disease. One should

  10. Pulse Check: The Importance of Self-Screening for Atrial Fibrillation Twice a Year

    MedlinePlus

    ... of self-screening for atrial fibrillation twice a year What is atrial fibrillation? Atrial fibrillation (AF) is ... adult do a pulse check routinely twice a year. A good time to remember to check your ...

  11. Modulation of local Ca2+ release sites by rapid fluid puffing in rat atrial myocytes.

    PubMed

    Woo, Sun-Hee; Risius, Tim; Morad, Martin

    2007-04-01

    Atrial myocytes that lack t-tubules appear to have two functionally separate sarcoplasmic Ca2+ stores: a peripheral store associated with plasmalemmal L-type calcium channels and a central store with no apparent proximity to L-type calcium channels. Here we describe a set of calcium sparks and waves that are triggered by puffing of pressurized (200-400 mmH2O) bathing solutions onto resting isolated rat atrial myocytes. Puffing of pressurized (200 mmH2O) solutions, identical to those bathing the myocytes from distances of approximately 150 microm onto the surface of a single myocyte triggered or enhanced spontaneously occurring peripheral sparks by five- to six-fold and central Ca2+ sparks by two- to three-fold, without altering the unitary spark properties. Exposure to higher pressure flows (400 mmH2O) often triggered longitudinally spreading Ca2+ waves. These results suggest that pressurized flows may directly modulate Ca2+ signaling of atrial myocytes by activating the intracellular Ca2+ release sites. PMID:17087992

  12. Atrial septal stenting — How I do it?

    PubMed Central

    Sivakumar, Kothandam

    2015-01-01

    A wide atrial communication is important to maintain hemodynamics in certain forms of congenital and acquired heart defects. In comparison to balloon septostomy or blade septostomy, atrial septal stenting provides a controlled, predictable, and long-lasting atrial communication. It often needs a prior Brockenbrough needle septal puncture to obtain a stable stent position. A stent deployed across a previously dilated and stretched oval foramen or tunnel form of oval foramen carries higher risk of embolization. This review provides technical tips to achieve a safe atrial septal stenting. Even though this is a “How to do it article,” an initial discussion about the indications for atrial septal stenting is vital as the resultant size of the atrial septal communication should be tailored for each indication. PMID:25684885

  13. Surviving catastrophic disintegration of a large left atrial myxoma: the importance of multi-disciplinary team.

    PubMed

    Habbab, Louay; Alfaraidi, Haifa; Lamy, Andre

    2014-01-01

    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. PMID:25217477

  14. Effects of Angiotensin-II Receptor Blocker on Inhibition of Thrombogenicity in a Canine Atrial Fibrillation Model

    PubMed Central

    Jung, Jae Seung; Kim, Min Kyung; Sim, Jaemin; Kim, Jin Seok; Lim, Hong Euy; Park, Sang Weon; Kim, Young-Hoon

    2016-01-01

    Background and Objectives Angiotensin-II receptor blockers (ARBs) are known to reduce the development of atrial fibrillation (AF) through reverse-remodeling. However, the effect of ARBs on thrombogenicity in AF remains unknown. Materials and Methods Twelve dogs were assigned to control (n=4), ARB (candesartan cilexitil 10 mg/kg/day p.o., 12 weeks; n=4), or sham (n=4) groups. Sustained AF was induced by rapid atrial pacing. Both arterial and venous serum levels of tissue inhibitor of matrix metalloproteinase-1, von Willebrand factor, P-selectin, and vascular cell adhesion molecule-1 (VCAM-1) were measured at baseline and during AF (0, 4, and 12 weeks) with enzyme-linked immunosorbent assay. Biopsies from both atria including the appendages were performed to semi-quantitatively assess endocardial and myocardial fibrosis after 12 weeks. Results The serum levels of bio-markers were not significantly different at baseline or during AF between the control and the candesartan groups. The levels were not significantly different over time, but there was a trend toward a decrease in arterial VCAM-1 from 4 to 12 weeks in the candesartan group compared to the control group. The grades of endocardial fibrosis after 12 weeks but not those of myocardial fibrosis were slightly reduced in the candesartan group compared to the control group. Conclusion This study did not show that the ARB candesartan significantly reverses thrombogenicity or fibrosis during AF. Future studies using a larger number of subjects are warranted to determine the therapeutic effect of renin-angiotensin-aldosterone system blockade on prothrombogenic processes in AF. PMID:27275170

  15. 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

  16. [PREVALENCE OF ATRIAL RHYTHM DISTURBANCES IN CARDIAC PATIENTS WITH COMORBIDITIES].

    PubMed

    Velichko, V L; Naychuk, O V; Lagoda, D O; Amirova, G U

    2015-01-01

    Atrial arrhythmias are the most common among all cardiac arrhythmias. The prevalence of atrial arrhythmias is increasing worldwide and has an impact on health indicators such as the loss of ability to work and mortality and increases the overall cardiovascular risk and/or heart disease occurence. This study indicates a high prevalence of atrial arthythmias in patients with ischemic heart disease and requires more detailed study in order to develop methods of preventing the onset of cardiac rhythm disorders. PMID:26118041

  17. 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. PMID:23608293

  18. 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

  19. Spectral Profiles of Complex Fractionated Atrial Electrograms Are Different in Longstanding and Acute Onset Atrial Fibrillation Atrial Electrogram Spectra

    PubMed Central

    Ciaccio, Edward J.; Biviano, Angelo B.; Whang, William; Gambhir, Alok; Garan, Hasan

    2015-01-01

    Background Spectral analysis of complex fractionated atrial electrograms (CFAE)may be useful for gaining insight into mechanisms underlying paroxysmal and longstanding atrial fibrillation (AF). The commonly used dominant frequency (DF) measurement has limitations. Method CFAE recordings were acquired from outside the 4 pulmonary vein ostia and at 2 left atrial free wall sites in 10 paroxysmal and 10 persistent AF patients. Two consecutive 8s-series were analyzed from recordings >16s in duration. Power spectra were computed for each 8s-series in the range 3–12 Hz and normalized. The mean and standard deviation of normalized power spectra (MPS and SPS, respectively) were compared for paroxysmal versus persistent CFAE. Also, the DF and its peak amplitude (ADF) were compared for pulmonary vein sites only. Power spectra were computed using ensemble average and Fourier methods. Results No significant changes occurred in any parameter from the first to second recording sequence. For both sequences, MPS and SPS were significantly greater, and DF and ADF were significantly less, in paroxysmals versus persistents. The MPS and ADF measurements from ensemble spectra produced the most significant differences in paroxysmals versus persistents (P < 0.0001). DF differences were less significant, which can be attributed to the relatively high variability of DF in paroxysmals. The MPS was correlated to the duration of uninterrupted persistent AF prior to electrophysiologic study (P = 0.01), and to left atrial volume for all AF (P < 0.05). Conclusions The MPS and ADF measurements introduced in this study are probably superior to DF for discerning power spectral differences in paroxysmal versus longstanding CFAE. PMID:22578068

  20. 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.

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

    PubMed

    Matějková, Adéla; Šteiner, Ivo

    2016-01-01

    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. PMID:27526304

  2. [Giant aneurysm of the inter-atrial septum].

    PubMed

    Akoudad, H; Cherti, M; Chaouki, S; Ztot, S; Haddour, L; el Mrabet, I; el Khadiri, A; Benmimoun, E G; Arharbi, A

    1999-01-01

    We report the case of a large atrial septal aneurysm and a review of the literature. Atrial septal aneurysm is found in 1-8% of normal subjects. Its prevalence is higher among patients with ischemic stroke. Transesophageal echocardiography is an optimal tool for the diagnosis of atrial septal aneurysm. The clinical course may be complicated by arterial embolism, but mechanical complications may also occur, as in this case. Due to the lack of general agreement, treatment options should be discussed on an individual basis for patients with atrial septal aneurysm. PMID:10093663

  3. Atrial Thrombus in a Neonate: A Diagnostic Challenge.

    PubMed

    Sheen, Alicia; De Oliveira, Elizabeth R; Kim, Richard W; Parham, David; Lakshmanan, Ashwini

    2015-04-01

    Introduction Left atrial thrombus is a rare finding in a neonate. In the previous literature, atrial thrombi have been associated with catheter placement or congenital heart disease in a preterm infant. Case We report the case of a full-term neonate with no known risk factors found to have a left atrial thrombus. The neonate was born at 38 weeks' gestation to a 31-year-old female via cesarean section who was sent to the normal nursery. On postnatal day 5, the infant was noted to have low-to-medium level of oxygen saturations (∼90%) and was transferred to the neonatal intensive care unit with an echocardiogram completed on postnatal day 6 demonstrating a mobile, pedunculated mass attached to the left atrial septum with an appearance concerning for atrial myxoma. The infant underwent surgical resection on postnatal day 8 and pathology revealed the mass to be a left atrial thrombus. Discussion The rare finding of an atrial thrombus in a neonate has previously been associated with central venous catheter placement or congenital heart disease. This case is unusual in that the patient had neither condition. Although echocardiogram findings appeared more consistent with atrial myxoma, final pathology revealed a left atrial thrombus. Additionally, hypercoagulability work-up for this neonate was largely negative. This report underscores the importance of identification, search for etiology, and prompt therapy to prevent potential catastrophic outcomes. PMID:26199791

  4. Fourier ventricular amplitude ratio to evaluate atrial septal defect

    SciTech Connect

    Makler, P.T. Jr.; McCarthy, D.M.; Adler, L.; Alavi, A.

    1985-05-01

    First harmonic Fourier analysis of gated blood pool scans results in the formation of two functional images, a phase and amplitude image. The authors have previously shown that the total amplitude values of the two ventricles can be used to quantitate valvular insufficiency. The ventricular amplitude ratio (VAR, left/right) in normals is 1.14 0.11 and patients with valvular insufficiency is elevated (0.3 0.77). In patients with atrial septal defect (ASD), the right ventricle has a larger stroke volume than the left ventricle, and the VAR should be less than unity. To evaluate whether the amplitude image would permit quantification of shunt flow in ASD, the authors compared the VAR to the OP/QS ratio determined by cardiac catheterization (cath) in 3 groups of patients; group I (n=9) had ASD without valvular insufficiency (one patient had right-to-left shunting due to tricuspid stenosis; group II (n=4) had ventricular septal defect; and group III (n=2) had ASD plus valvular insufficiency. QP/QS shunt flow is also determined in group I using standard first-pass radionuclide angiography (rna). The data suggest that the VAR technique accurately determines the magnitude of shunt flow in ASD patients without concomitant valvular insufficiency.

  5. Pericardioesophageal Fistula Following Left Atrial Ablation Procedure

    PubMed Central

    Bailey, Christopher W.; Tallaksen, Robert J.

    2014-01-01

    We present a case of pericardioesophageal fistula formation in a 40 year old male who 23 days after undergoing a repeat ablation procedure for atrial fibrillation developed chest pressure, chills and diaphoresis. After initial labs and tests that demonstrated no evidence for acute myocardial ischemia, the patient underwent CT angiography of the chest. The study revealed pneumopericardium and a pericardial effusion. Suspicion was raised of perforation of the posterior left atrial myocardial wall with injury to adjacent esophagus. Water soluble contrast with transition to barium sulfate esophagram subsequently performed identified a perforation further affirming the postulate of a fistulous communication between the esophagus and pericardium. Transthoracic echocardiogram confirmed pericardial effusion but did not demonstrate myocardial defect. Endoscopic management was preferred and an esophageal stent was placed. Follow up esophagram showed an intact esophageal stent without evidence of extravasation. PMID:25426222

  6. Left Atrial Anatomy Relevant to Catheter Ablation

    PubMed Central

    Sánchez-Quintana, Damián; Cabrera, José Angel; Saremi, Farhood

    2014-01-01

    The rapid development of interventional procedures for the treatment of arrhythmias in humans, especially the use of catheter ablation techniques, has renewed interest in cardiac anatomy. Although the substrates of atrial fibrillation (AF), its initiation and maintenance, remain to be fully elucidated, catheter ablation in the left atrium (LA) has become a common therapeutic option for patients with this arrhythmia. Using ablation catheters, various isolation lines and focal targets are created, the majority of which are based on gross anatomical, electroanatomical, and myoarchitectual patterns of the left atrial wall. Our aim was therefore to review the gross morphological and architectural features of the LA and their relations to extracardiac structures. The latter have also become relevant because extracardiac complications of AF ablation can occur, due to injuries to the phrenic and vagal plexus nerves, adjacent coronary arteries, or the esophageal wall causing devastating consequences. PMID:25057427

  7. Atrial fibrillation due to licorice root syrup.

    PubMed

    Erkuş, Musluhittin Emre; Altıparmak, İbrahim Halil; Demirbağ, Recep; Günebakmaz, Özgür

    2016-04-01

    While it is known that consumption of licorice may lead to cardiac arrhythmias, there have been no reports of atrial fibrillation resulting from the consumption of licorice root syrup. A 57-year-old male with no prior history of cardiovascular disease was admitted to the emergency department with palpitation. His electrocardiogram showed atrial fibrillation with a moderate to rapid ventricular rate. In laboratory assessment, potassium was 2.0 mmol/L and plasma renin activity and aldosterone level were suppressed (<300 ng/L/hour, 42 ng/L respectively). Volumes of the heart chambers were within normal range and functions and structures of the heart valves were normal in echocardiographic assessment. The arrhythmia was resolved with propafenone infusion. PMID:27138313

  8. Pericardioesophageal fistula following left atrial ablation procedure.

    PubMed

    Bailey, Christopher W; Tallaksen, Robert J

    2014-10-01

    We present a case of pericardioesophageal fistula formation in a 40 year old male who 23 days after undergoing a repeat ablation procedure for atrial fibrillation developed chest pressure, chills and diaphoresis. After initial labs and tests that demonstrated no evidence for acute myocardial ischemia, the patient underwent CT angiography of the chest. The study revealed pneumopericardium and a pericardial effusion. Suspicion was raised of perforation of the posterior left atrial myocardial wall with injury to adjacent esophagus. Water soluble contrast with transition to barium sulfate esophagram subsequently performed identified a perforation further affirming the postulate of a fistulous communication between the esophagus and pericardium. Transthoracic echocardiogram confirmed pericardial effusion but did not demonstrate myocardial defect. Endoscopic management was preferred and an esophageal stent was placed. Follow up esophagram showed an intact esophageal stent without evidence of extravasation. PMID:25426222

  9. [Innovative techniques in atrial fibrillation therapy].

    PubMed

    Metzner, A; Wissner, E; Fink, T; Ouyang, F; Kuck, K-H

    2015-02-01

    Pulmonary vein isolation (PVI) is the established cornerstone in most catheter-based ablation treatment strategies for atrial fibrillation (AF); however, it is still a challenge to create contiguous, transmural and permanent ablation lesions using radiofrequency current in combination with three-dimensional mapping systems. To overcome these limitations, innovative spiral mapping and ablation catheters as well as balloon-based ablation catheters incorporating alternative energy sources, such as cryoenergy and laser were developed and evaluated and have proved their potential for safe and clinically effective PVI. In addition, novel ablation strategies, such as identification and ablation of AF-inducing foci and/or AF-perpetuating rotors using either endocardial or epicardial mapping systems were introduced and are currently under clinical evaluation. The identification and modulation of atrial ganglionic plexi (GP) and, therefore, of the autonomous nervous system is another additive ablation approach which requires further clinical evaluation. PMID:25585587

  10. 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

  11. Atrial-like cardiomyocytes from human pluripotent stem cells are a robust preclinical model for assessing atrial-selective pharmacology

    PubMed Central

    Devalla, Harsha D; Schwach, Verena; Ford, John W; Milnes, James T; El-Haou, Said; Jackson, Claire; Gkatzis, Konstantinos; Elliott, David A; Chuva de Sousa Lopes, Susana M; Mummery, Christine L; Verkerk, Arie O; Passier, Robert

    2015-01-01

    Drugs targeting atrial-specific ion channels, Kv1.5 or Kir3.1/3.4, are being developed as new therapeutic strategies for atrial fibrillation. However, current preclinical studies carried out in non-cardiac cell lines or animal models may not accurately represent the physiology of a human cardiomyocyte (CM). In the current study, we tested whether human embryonic stem cell (hESC)-derived atrial CMs could predict atrial selectivity of pharmacological compounds. By modulating retinoic acid signaling during hESC differentiation, we generated atrial-like (hESC-atrial) and ventricular-like (hESC-ventricular) CMs. We found the expression of atrial-specific ion channel genes, KCNA5 (encoding Kv1.5) and KCNJ3 (encoding Kir 3.1), in hESC-atrial CMs and further demonstrated that these ion channel genes are regulated by COUP-TF transcription factors. Moreover, in response to multiple ion channel blocker, vernakalant, and Kv1.5 blocker, XEN-D0101, hESC-atrial but not hESC-ventricular CMs showed action potential (AP) prolongation due to a reduction in early repolarization. In hESC-atrial CMs, XEN-R0703, a novel Kir3.1/3.4 blocker restored the AP shortening caused by CCh. Neither CCh nor XEN-R0703 had an effect on hESC-ventricular CMs. In summary, we demonstrate that hESC-atrial CMs are a robust model for pre-clinical testing to assess atrial selectivity of novel antiarrhythmic drugs. PMID:25700171

  12. Left atrial thrombus under dabigatran in a patient with nonvalvular atrial fibrillation.

    PubMed

    Janssen, A M; van de Kerkhof, D; Szabó, B; Durian, M F; van der Voort, P H

    2016-08-01

    Dabigatran is a new direct competitive inhibitor of thrombin and is equally effective and safe as warfarin in the prevention of thromboembolism in patients with nonvalvular atrial fibrillation. We present a case of a 60-year-old man with persistent nonvalvular atrial fibrillation who switched from acenocoumarol to dabigatran 110 mg twice daily. After five months the patient developed a large atrial thrombus, occlusion of the tibial arteries of the right foot, cerebellar infarction and multiple infarctions in kidneys and spleen. Blood test showed a dabigatran concentration of 35 ng/ml six hours after intake, correlating with a low trough concentration of 24-27 ng/mL and significantly increased thromboembolic risk. Other risk factors for thromboembolism were excluded. The present case indicates that in selected patients, there might be an indication for dose adjustments based on serum levels of dabigatran to ensure patient efficacy (thromboembolic events) and safety (bleeding). PMID:27571947

  13. Right atrial chromaffin paraganglioma in a dog.

    PubMed

    Wey, Aaron C; Moore, Frances M

    2012-09-01

    Cardiac neoplasia is relatively uncommon in canine patients, with the most common neoplasms including right atrial hemangiosarcoma and paragangliomas occurring at the heart base (i.e. chemodectomas or aortic body tumors). Intracardiac paragangliomas are rare neoplasms in humans and have seldom been documented in the veterinary literature. This report describes the clinical course and histopathological findings in an adult canine patient with an intracardiac chromaffin paraganglioma (non-adrenal pheochromocytoma) of the right atrium. PMID:22840732

  14. Restrictive atrial septum after the Fontan procedure.

    PubMed

    Penford, Gemma; Quandt, Daniel; Stumper, Oliver

    2016-03-01

    In this study, three patients presenting with early or late postoperative Fontan complications were identified to suffer from restriction of the native atrial septum. This caused significant obstruction to pulmonary venous return and elevated systemic venous pressure. Dobutamine stress testing was used in one patient to identify this lesion. Transcatheter stenting was performed in the other two patients. Patients improved after relief of the obstruction. PMID:26175163

  15. 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

  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. Delay in diagnosis of right atrial myxoma

    SciTech Connect

    Northcote, R.J.; Sethia, B.; Ballantyne, D.

    1985-02-01

    Clinical, echocardiographic, and nuclear angiographic findings in a 51-year-old woman who presented with a history of dyspnea are discussed. Initial echocardiography revealed no abnormality. However, a subsequent radionuclide angiogram revealed a filling defect on the right side of the heart. This represented a right atrial myxoma. Radionuclide angiography can provide a useful noninvasive tool in the diagnosis of intracardiac tumors when echocardiography has not been helpful.

  18. Diagnosis of the cavo-hepato-atrial pathway in Budd-Chiari syndrome by ultrasonography.

    PubMed

    Gai, Yong-Hao; Cai, Shi-Feng; Fan, Hui-Li; Liu, Qing-Wei

    2014-09-01

    The aim of this study was to investigate the ultrasonic features of the cavo-hepato-atrial pathway in Budd-Chiari syndrome (BCS), by which blood is drained from the occluded inferior vena cava (IVC) to the right atrium via hepatic veins. Ultrasonograms from 11 patients with BCS with cavo-hepato-atrial pathways were retrospectively studied. Doppler ultrasound was used to observe the direction of the flow and measure the velocity of the blood-draining vessels. Blood flow in the draining vessels and the collaterals was shown as blue, red or bicolored depending on whether the flow direction was away from the transducer, towards the transducer or both. For measurement, the Doppler angle between the axis of the Doppler beam and that of the vein examined was always <60°. Ultrasonography was performed 1-2 weeks prior to digital subtraction angiography (DSA). All patients were confirmed by DSA. Membranous and segmental occlusions of IVCs were observed in seven and four cases, respectively. Blood flow from the IVC reversed to the hepatic/accessory hepatic vein, continued through the dilated intrahepatic collaterals, onward to the other hepatic vein and finally to the right atrium. The majority of the inlets (8/11) of hepatic veins above the occlusion were narrow compared with the dilated distant parts of the lumens. Accelerated blood flow in the inlets was detected in all patients regardless of the luminal diameter. In conclusion, the results from the present study suggest that the unusual cavo-hepato-atrial pathway can be diagnosed reliably by ultrasonography, which may be useful for clinical management. PMID:25120601

  19. Hemolymph circulation in insect sensory appendages: functional mechanics of antennal accessory pulsatile organs (auxiliary hearts) in the mosquito Anopheles gambiae.

    PubMed

    Boppana, Sushma; Hillyer, Julián F

    2014-09-01

    Mosquito antennae provide sensory input that modulates host-seeking, mating and oviposition behaviors. Thus, mosquitoes must ensure the efficient transport of molecules into and out of these appendages. To accomplish this, mosquitoes and other insects have evolved antennal accessory pulsatile organs (APOs) that drive hemolymph into the antennal space. This study characterizes the structural mechanics of hemolymph propulsion throughout the antennae of Anopheles gambiae. Using intravital video imaging, we show that mosquitoes possess paired antennal APOs that are located on each side of the head's dorsal midline. They are situated between the frons and the vertex in an area that is dorsal to the antenna but ventral to the medial-most region of the compound eyes. Antennal APOs contract in synchrony at 1 Hz, which is 45% slower than the heart. By means of histology and intravital imaging, we show that each antennal APO propels hemolymph into the antenna through an antennal vessel that traverses the length of the appendage and has an effective diameter of 1-2 μm. When hemolymph reaches the end of the appendage, it is discharged into the antennal hemocoel and returns to the head. Because a narrow vessel empties into a larger cavity, hemolymph travels up the antenna at 0.2 mm s(-1) but reduces its velocity by 75% as it returns to the head. Finally, treatment of mosquitoes with the anesthetic agent FlyNap (triethylamine) increases both antennal APO and heart contraction rates. In summary, this study presents a comprehensive functional characterization of circulatory physiology in the mosquito antennae. PMID:24948635

  20. 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

  1. Atrial fibrillation pearls and perils of management.

    PubMed Central

    Kudenchuk, P J

    1996-01-01

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

  2. Atrial fibrillation: effects beyond the atrium?

    PubMed Central

    Wijesurendra, Rohan S.; Casadei, Barbara

    2015-01-01

    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. PMID:25587048

  3. Detection of occult paroxysmal atrial fibrillation.

    PubMed

    Petrėnas, Andrius; Sörnmo, Leif; Lukoševičius, Arūnas; Marozas, Vaidotas

    2015-04-01

    This work introduces a novel approach to the detection of brief episodes of paroxysmal atrial fibrillation (PAF). The proposed detector is based on four parameters which characterize RR interval irregularity, P-wave absence, f-wave presence, and noise level, of which the latter three are determined from a signal produced by an echo state network. The parameters are used for fuzzy logic classification where the decisions involve information on prevailing signal quality; no training is required. The performance is evaluated on a large set of test signals with brief episodes of PAF. The results show that episodes with as few as five beats can be reliably detected with an accuracy of 0.88, compared to 0.82 for a detector based on rhythm information only (the coefficient of sample entropy); this difference in accuracy increases when atrial premature beats are present. The results also show that the performance remains essentially unchanged at noise levels up to [Formula: see text] RMS. It is concluded that the combination of information on ventricular activity, atrial activity, and noise leads to substantial improvement when detecting brief episodes of PAF. PMID:25502852

  4. [Medicinal rhythm control in atrial fibrillation].

    PubMed

    Nowak, Bernd; Fürnkranz, Alexander

    2014-03-01

    Medicinal antiarrhythmic therapy is either used in the acute setting to convert atrial fibrillation to sinus rhythm or as chronic medication to preserve sinus rhythm if a rhythm control strategy is followed. The choice of the antiarrhythmic agent is based on the presence or absence of structural heart disease. In addition, oral anticoagulation should be established according to current guidelines. In the acute setting the armamentarium comprises flecainide, propafenone, vernakalant and amiodarone. Usually, combination therapy with an atrioventricular (AV) node slowing drug (a beta blocker or verapamil) is used. For chronic rhythm control a class IC drug, such as sotalol, dronedarone and amiodarone is given depending on the comorbidities. In the absence of structural heart disease, rare episodes of paroxysmal atrial fibrillation can be treated by a pill-in-the-pocket strategy, i.e. self-administered pharmacological cardioversion with flecainide or propafenone. Despite recent advances in catheter ablation of atrial fibrillation, medical rhythm control continues to play an important role due to its ubiquitous availability and relatively easy use. The risk for proarrhythmia has to be evaluated in all patients. PMID:24549989

  5. Animal Studies of Epicardial Atrial Ablation

    PubMed Central

    Schuessler, Richard B.; Lee, Anson M.; Melby, Spencer J.; Voeller, Rochus K.; Gaynor, Sydney L.; Sakamoto, Shun-Ichiro; Damiano, Ralph J.

    2009-01-01

    The Cox-Maze procedure is an effective treatment for atrial fibrillation with a long-term freedom from recurrence of >90%. The original procedure was highly invasive and required cardiopulmonary bypass (CPB). Modifications of the procedure have been proposed so that the procedure can be done without CPB. These approaches proposed to use 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 the atrial wall muscle thickness is extremely variable and 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 to create 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. These include four radiofrequency, two microwave, two lasers, and one cryothermic device. The maximum penetration of any device was 8.3 mm. All devices except one, the Atricure IsolatorT pen, failed to penetrate 2.0 mm in some non-transmural sections. Future development of unidirectional energy sources should be directed at increasing the maximum depth and the consistency of penetration. PMID:19959142

  6. Muscles of chondrichthyan paired appendages: comparison with osteichthyans, deconstruction of the fore-hindlimb serial homology dogma, and new insights on the evolution of the vertebrate neck.

    PubMed

    Diogo, R; Ziermann, J M

    2015-03-01

    Here we present the first study comparing all the paired appendages muscles of representatives of each major extant gnathostome group. We address a crucial and enigmatic question in evolutionary and comparative anatomy: Why are the pelvic and pectoral appendages of gnathostomes, and particularly of tetrapods, in general so similar to each other? We argue that an integrative analysis of the new myological data and the information from the literature contradicts the idea that the forelimbs and hindlimbs are serial homologues. The data show that many of the strikingly similar fore- and hindlimb muscles of extant tetrapods evolved independently in each appendage because the ancestors of extant gnathostomes and osteichthyans only had an adductor and an abductor in each fin. Therefore, these data contradict the idea that at least some muscles present in the tetrapod fore- and hindlimbs were already present in some form in the first fishes with pectoral and pelvic appendages, as the result of an ancestral duplication of the paired appendages leading to a true serial homology. The origin of the pectoral girdle was instead likely related to head evolution, as illustrated by the cucullaris of gnathostomes such as chondrichthyans inserting onto both the branchial arches and pectoral girdle. Only later in evolution the cucullaris became differentiated into the levatores arcuum branchialium and protractor pectoralis, which gave rise to the amniote neck muscles trapezius and sternocleidomastoideus. These changes therefore contributed to an evolutionary trend toward a greater anatomical and functional independence of the pectoral girdle from head movements. PMID:25205543

  7. Passive and Active Flow Control by Swimming Fishes and Mammals

    NASA Astrophysics Data System (ADS)

    Fish, F. E.; Lauder, G. V.

    2006-01-01

    What mechanisms of flow control do animals use to enhance hydrodynamic performance? Animals are capable of manipulating flow around the body and appendages both passively and actively. Passive mechanisms rely on structural and morphological components of the body (i.e., humpback whale tubercles, riblets). Active flow control mechanisms use appendage or body musculature to directly generate wake flow structures or stiffen fins against external hydrodynamic loads. Fish can actively control fin curvature, displacement, and area. The vortex wake shed by the tail differs between eel-like fishes and fishes with a discrete narrowing of the body in front of the tail, and three-dimensional effects may play a major role in determining wake structure in most fishes.

  8. P wave morphology in guiding the ablation strategy of focal atrial tachycardias and atrial flutter.

    PubMed

    Lee, Justin M S; Fynn, Simon P

    2015-01-01

    Focal atrial tachycardias arise preferentially from specific locations within the atria. Careful analysis of the P wave can provide useful information about the chamber and likely site of origin within that chamber. Macro-reentrant atrial flutter also tends to occur over a limited number of potential circuits. In this case, the ECG usually gives a guide to the chamber of origin, but unless it shows a specific morphology it is less useful in delineating the circuit involved. Nonetheless, prior knowledge of the likely chamber of origin helps to plan the ablation strategy. PMID:25308814

  9. P Wave Morphology in Guiding the Ablation Strategy of Focal Atrial Tachycardias and Atrial Flutter

    PubMed Central

    Lee, Justin M. S; Fynn, Simon P

    2015-01-01

    Focal atrial tachycardias arise preferentially from specific locations within the atria. Careful analysis of the P wave can provide useful information about the chamber and likely site of origin within that chamber. Macro-reentrant atrial flutter also tends to occur over a limited number of potential circuits. In this case, the ECG usually gives a guide to the chamber of origin, but unless it shows a specific morphology it is less useful in delineating the circuit involved. Nonetheless, prior knowledge of the likely chamber of origin helps to plan the ablation strategy. PMID:25308814

  10. Percutaneous closure of atrial septal defects leads to normalisation of atrial and ventricular volumes

    PubMed Central

    Teo, Karen SL; Dundon, Benjamin K; Molaee, Payman; Williams, Kerry F; Carbone, Angelo; Brown, Michael A; Worthley, Matthew I; Disney, Patrick J; Sanders, Prashanthan; Worthley, Stephen G

    2008-01-01

    Background Percutaneous closure of atrial septal defects (ASDs) should potentially reduce right heart volumes by removing left-to-right shunting. Due to ventricular interdependence, this may be associated with impaired left ventricular filling and potentially function. Furthermore, atrial changes post-ASD closure have been poorly understood and may be important for understanding risk of atrial arrhythmia post-ASD closure. Cardiovascular magnetic resonance (CMR) is an accurate and reproducible imaging modality for the assessment of cardiac function and volumes. We assessed cardiac volumes pre- and post-percutaneous ASD closure using CMR. Methods Consecutive patients (n = 23) underwent CMR pre- and 6 months post-ASD closure. Steady state free precession cine CMR was performed using contiguous slices in both short and long axis views through the ASD. Data was collected for assessment of left and right atrial, ventricular end diastolic volumes (EDV) and end systolic volumes (ESV). Data is presented as mean ± SD, volumes as mL, and paired t-testing performed between groups. Statistical significance was taken as p < 0.05. Results There was a significant reduction in right ventricular volumes at 6 months post-ASD closure (RVEDV: 208.7 ± 76.7 vs. 140.6 ± 60.4 mL, p < 0.0001) and RVEF was significantly increased (RVEF 35.5 ± 15.5 vs. 42.0 ± 15.2%, p = 0.025). There was a significant increase in the left ventricular volumes (LVEDV 84.8 ± 32.3 vs. 106.3 ± 38.1 mL, p = 0.003 and LVESV 37.4 ± 20.9 vs. 46.8 ± 18.5 mL, p = 0.016). However, there was no significant difference in LVEF and LV mass post-ASD closure. There was a significant reduction in right atrial volumes at 6 months post-ASD closure (pre-closure 110.5 ± 55.7 vs. post-closure 90.7 ± 69.3 mL, p = 0.019). Although there was a trend to a decrease in left atrial volumes post-ASD closure, this was not statistically significant (84.5 ± 34.8 mL to 81.8 ± 44.2 mL, p = NS). Conclusion ASD closure leads to

  11. 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

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

    PubMed

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

    2013-12-01

    Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and a major cause of stroke. In the mammalian heart the gap junction proteins connexin40 (Cx40) and connexin43 (Cx43) are strongly expressed in the atrial myocardium mediating effective propagation of electrical impulses. Different heterozygous mutations in the coding region for Cx40 were identified in patients with AF. We have generated transgenic Cx40A96S mice harboring one of these mutations, the loss-of-function Cx40A96S mutation, as a model for atrial fibrillation. Cx40A96S mice were characterized by immunochemical and electrophysiological analyses. Significantly reduced atrial conduction velocities and strongly prolonged episodes of atrial fibrillation were found after induction in Cx40A96S mice. Analyses of the gating properties of Cx40A96S channels in cultured HeLa cells also revealed significantly lower junctional conductance and enhanced sensitivity voltage gating of Cx40A96S in comparison to Cx40 wild-type gap junctions. This is caused by reduced open probabilities of Cx40A96S gap junction channels, while single channel conductance remained the same. Similar to the corresponding patient, heterozygous Cx40A96S mice revealed normal expression levels and localization of the Cx40 protein. We conclude that heterozygous Cx40A96S mice exhibit prolonged episodes of induced atrial fibrillation and severely reduced atrial conduction velocities similar to the corresponding human patient. PMID:24060583

  13. Role of endogenous atrial natriuretic factor in acute congestive heart failure.

    PubMed Central

    Lee, M E; Miller, W L; Edwards, B S; Burnett, J C

    1989-01-01

    The current studies were designed to investigate the functional significance of elevated endogenous atrial natriuretic factor (ANF) in acute congestive heart failure (CHF). Integrated cardiorenal and endocrine function were measured in three models of acute low-output congestive heart failure with comparably reduced cardiac output (CO) and mean arterial pressure (MAP). Acute CHF was produced by rapid right ventricular pacing (group I, n = 5) which decreases CO and increases atrial pressures and plasma ANF. In group II, n = 5, thoracic inferior vena caval constriction (TIVCC) was produced to decrease venous return and CO but without increases in atrial pressure or plasma ANF. In group III, n = 5, TIVCC was performed and exogenous ANF infused to achieve plasma concentrations observed in acute CHF. In acute CHF with increases in endogenous ANF, sodium excretion (UNaV), renal blood flow (RBF), plasma renin activity (PRA), and plasma aldosterone (PA) were maintained despite decreases in CO and MAP. In contrast, TIVCC with similar reductions in CO and MAP but without increases in ANF resulted in decreases in UNaV and RBF and increases in PRA and PA. Exogenous administration of ANF in TIVCC to mimic levels in acute CHF prevented sodium retention, renal vasoconstriction, and activation of renin and aldosterone. These studies demonstrate that endogenous ANF serves as an important physiologic volume regulator in acute CHF to maintain sodium excretion and possibly participate in the suppression of activation of the renin-angiotensin-aldosterone system despite the stimulus of arterial hypotension. Images PMID:2531762

  14. Effects of spironolactone towards rabbit atrial remodeling with rapid pacing.

    PubMed

    Wang, Lian-Fa; Gu, Lei; Huang, Meng-Xun; Zhou, Wen-Bing; Li, Hua; Zhang, Bang-Zhu

    2016-01-01

    This study aimed to observe the effects of spironolactone towards the rabbit atrial remodeling with rapid atrial pacing (RAP). 30 rabbits were randomly divided into control group, RAP group and spironolactone group, with 10 rabbits in each group. RAP was performed at the speed of 800 beats/min for 8 h, atrial effective refractory period (AERP) was determined before and at the 1(st), 2(nd), 4(th), 6(th) and 8(th) of the pacing, the expressions of atrial muscular calcium channel α1C subunit and β1 subunit mRNA were performed the RT-PCR detection, and ultrastructural changes of atrial myocytes were observed. AERP of RAP group shortened, with poor frequency adaptability; the expressions of calcium channel α1C subunit and β1 subunit mRNA decreased 22% and 26%, respectively, when compared with the control group; ultrastructure of atrial myocytes changed significantly. AERP of spironotlactone group shortened less that RAP group, and the frequency adaptability was maintained, the decreased expressions of calcium channel α1C subunit and β1 subunit mRNA significantly reduced. RAP could cause atrial remodeling, while spironolactone could inhibit RAP-induced atrial remodeling. PMID:26826809

  15. Novel Interventional Strategies for the Treatment of Atrial Fibrillation

    PubMed Central

    Siontis, Konstantinos C; Oral, Hakan

    2016-01-01

    The landscape of the invasive management of atrial fibrillation, the most common sustained arrhythmia in humans, has changed dramatically in the last decade owing to numerous advances in arrhythmia mapping and ablation technologies. The current review critically appraises novel interventional strategies for the treatment of atrial fibrillation with a focus on clinical effectiveness and safety. PMID:27403294

  16. [Pharmacological cardioversion with intravenous propafenone in atrial fibrillation].

    PubMed

    Velázquez Rodríguez, E; Cancino Rodríguez, C; Arias Estrada, S; Rangel Rojo, J; Hernández Morales, E; Uribe Muñoz, A

    2000-01-01

    The efficacy and safety of intravenous propafenone for conversion of recent-onset and chronic atrial fibrillation was assessed in 46 patients. 40 with atrial fibrillation associated with or without structural heart disease (mean age 63 +/- 14 years) and 6 patients with atrial fibrillation related to the Wolff-Parkinson-White syndrome (mean age 34.8 +/- 13 years). Propafenone treatment was administered at 2 mg/kg over 15 minutes under continuous electrocardiographic monitoring. In 28 of 32 (87.5%) patients with paroxysmal and/or recent-onset atrial fibrillation a stable sinus rhythm was restored within 1 hour after propafenone (mean 17 +/- 11 minutes) and in only 3 of 8 (37.5%) with chronic atrial fibrillation (p < 0.05). Conversion to sinus rhythm was obtained in 5 of 6 (83.3%) patients with atrial fibrillation related ventricular preexcitation, mean time 21 +/- 12 minutes. Propafenone had an additional effect reducing mean heart rate (141 +/- 21 to 102 +/- 15 beat per minute, p < 0.05) and the shortest preexcited R-R intervals was increased, mean 231.6 +/- 27.8 to 355 +/- 37.2 milliseconds (p < 0.001) in cases associated with ventricular preexcitation. Dizziness, hypotension and transient conduction disturbances occurred in only one patient with rheumatic valvular heart disease: EF 40%. Propafenone is an effective and safe antiarrhythmic drug for converting paroxysmal and/or recent-onset atrial fibrillation of various origins with a more limited efficacy in chronic atrial fibrillation. PMID:10932801

  17. 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.

  18. Bolus injection of acetylcholine terminates atrial fibrillation in rats.

    PubMed

    Fleidervish, Ilya A; Goldberg, Yuri; Ovsyshcher, I Eli

    2008-01-28

    It is well established that a tonic increase in the availability of the atrial muscarinic K(+) channels, either by enhanced vagal tone or by steady infusion of a low-dose of cholinergic or adenosine receptor agonists, promotes the genesis of atrial fibrillation. Here, we aimed to test the hypothesis that bolus administration of a muscarinic receptor agonist would destabilize and terminate atrial arrhythmia by uniformly and transiently activating K(+) channels throughout the atria, and that if the agonist was rapidly hydrolysable, it would dissipate before the more tonic, pro-arrhythmic effects could take hold. The episodes of untreated atrial fibrillation, induced in anesthetized rats by programmed electrical stimulation via trans-esophageal bipolar catheter, lasted on average 8.6+/-2.2 min (n=32). Intravenous injection of a model hydrolysable muscarinic agonist, acetylcholine (0.2 mg/kg body weight), converted atrial fibrillation into sinus rhythm within 8.4+/-1.9 s (n=10, P<0.05). The termination of an atrial fibrillation episode was always accompanied by transient bradycardia; the sinus rhythm gradually accelerated and reached pre-atrial fibrillation values within 10-20 s of injection. In conclusion, our evidence indicates that bolus administration of rapidly hydrolysable muscarinic agonist could be an effective way to pharmacologically terminate atrial fibrillation and restore sinus rhythm. PMID:18078927

  19. Dual chamber pacing mode in an atrial antitachycardia pacing device without a ventricular lead – A necessary evil

    PubMed Central

    Noheria, Amit; Friedman, Paul A.; Asirvatham, Samuel J.; McLeod, Christopher J.

    2015-01-01

    We present a case of a single chamber atrial pacemaker implanted for sinus node dysfunction and treatment of macroreentrant atrial tachycardias with atrial antitachycardia pacing. The patient presented with sustained atrial tachycardia above the detection rate, however, the device was unable to detect the tachycardia and did not deliver the programmed therapy. We discuss the nuances of the atrial tachyarrhythmia detection algorithms, and the programming strategies to maximize detection of atrial arrhythmias in a single chamber atrial pacemaker. PMID:26937101

  20. Mechanics of breathing in patients with atrial septal defect.

    PubMed

    Troyer, A D; Yernault, J C; Englert, M

    1977-03-01

    Mechanics of breathing and pulmonary diffusing properties were investigated in 24 adult patients with atrial septal defect. The patients were divided into 3 groups according to mean pulmonary artery pressure: less than 19 mm Hg (group I), 20 to 24 mm Hg (group II), and greater than 25 mm Hg (group III). The only change observed in group I was a marked increase in diffusing capacity. Patients of group II showed not only an increase in diffusing capacity, but also an overt decrease in maximal expiratory flow at all lung volumes and at any given driving pressure. For these two groups, a highly significant inverse correlation was found between changes in diffusing and elastic lung properties (r = -0.71; P less than 0.001). In patients of group III, the expiratory flow remained clearly decreased; furthermore, lung compliance and lung volumes were sharply reduced, airway resistance was elevated, and diffusing capacity was normal. Finally, from group I to group III, the lung elastic recoil became progressively diminished at small lung volumes. These results suggest that an increased pulmonary blood volume induces an increase in diffusing capacity and a slight decrease in lung compliance. Simultaneous existance of high intravascular pressure strengthens the effects of increased pulmonary blood volume on lung mechanics and results in significant abnormalities in the lung mechanical behavior. It is postulated that these effects are due to a competition for space between vessels and airways within the bronchovascular sheaths, with a subsequent compression of small airways. PMID:842953

  1. Atrial natriuretic peptide increases resistance to venous return in rats

    SciTech Connect

    Chien, Y.W.; Frohlich, E.D.; Trippodo, N.C.

    1987-05-01

    To examine mechanisms by which administration of atrial natriuretic peptide (ANP) decreases venous return, the authors compared the hemodynamic effects of ANP furosemide (FU), and hexamethonium (HEX) with those of vehicle (VE) in anesthetized rats. Compared with VE, ANP reduced mean arterial pressure, central venous pressure, and cardiac index and increased calculated resistance to venous return. /sup 141/Ce-labeled microspheres were used to determine cardiac output. Mean circulatory filling pressure, distribution of blood flow between splanchnic organs and skeletal muscles, and total peripheral resistance remained unchanged. FU increased urine output similar to that of ANP, yet produced no hemodynamic changes, dissociating diuresis, and decreased cardiac output. HEX lowered arterial pressure through a reduction in total peripheral resistance without altering cardiac output or resistance to venous return. The results confirm previous findings that ANP decreases cardiac output through a reduction in venous return and suggest that this results partly from increased resistance to venous return and not from venodilation or distribution of blood flow.

  2. 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

    2013-01-01

    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. PMID:23135670

  3. 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.

  4. 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

  5. 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

    2015-01-01

    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

  6. Dronedarone for atrial fibrillation: a new therapeutic agent

    PubMed Central

    Patel, Pawan D; Bhuriya, Rohit; Patel, Dipal D; Arora, Bhaskar L; Singh, Param P; Arora, Rohit R

    2009-01-01

    Atrial fibrillation is the most common of the serious cardiac rhythm disturbances and is responsible for substantial morbidity and mortality. Amiodarone is currently one of the most widely used and most effective antiarrhythmic agents for atrial fibrillation. But during chronic usage amiodarone can cause some serious extra cardiac adverse effects, including effects on the thyroid. Dronedarone is a newer therapeutic agent with a structural resemblance to amiodarone, with two molecular changes, and with a better side effect profile. Dronedarone is a multichannel blocker and, like amiodarone, possesses both a rhythm and a rate control property in atrial fibrillation. The US Food and Drug Administration approved dronedarone for atrial fibrillation on July 2, 2009. In this review, we discuss the role of dronedarone in atrial fibrillation. PMID:19688104

  7. Global burden of atrial fibrillation in developed and developing nations.

    PubMed

    Chugh, Sumeet S; Roth, Gregory A; Gillum, Richard F; Mensah, George A

    2014-03-01

    Atrial fibrillation is the most common heart rhythm disorder in the world, with major public health impact especially due to increased risk of stroke and hospitalizations. The recently published results on epidemiology of atrial fibrillation from the Global Burden of Diseases, Injuries, and Risk Factors Study confirm the existence of a significant and progressive worldwide increase in the burden of atrial fibrillation. However, there appears to be regional variation in both the burden of atrial fibrillation and availability of epidemiological data regarding this condition. In this review, the authors identify issues that are unique to the developed versus developing regions and outline a road map for possible approaches to surveillance, management, and prevention of atrial fibrillation at the global level. PMID:25432121

  8. 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.

  9. What have we learned of ablation procedures for atrial fibrillation?

    PubMed

    Maurer, T; Lundqvist, C B; Tilz, R; Mont, L; Chierchia, G-B; Malmborg, H; Metzner, A; Kuck, K-H

    2016-05-01

    Atrial fibrillation is a widespread disease of growing clinical, economic and social importance. Interventional therapy for atrial fibrillation offers encouraging results, with pulmonary vein isolation (PVI) as the established cornerstone. Yet, the challenge to create durable transmural lesions remains, leading to recurrence of atrial fibrillation in long-term follow-up even after multiple ablation procedures in 20% of patients with paroxysmal atrial fibrillation and approximately 50% with persistent atrial fibrillation. To overcome these limitations, innovative tools such as the cryoballoon and contact force catheters have been introduced and have demonstrated their potential for safe and effective PVI. Furthermore, advanced pharmacological and pacing manoeuvres enhance evaluation of conduction block in PVI. PMID:26940476

  10. Estimation of pulmonary wedge pressure by transmitral Doppler in patients with chronic heart failure and atrial fibrillation.

    PubMed

    Temporelli, P L; Scapellato, F; Corrà, U; Eleuteri, E; Imparato, A; Giannuzzi, P

    1999-03-01

    Previous studies have demonstrated that left ventricular (LV) filling pressures can be estimated from transmitral Doppler recording in patients in sinus rhythm who have a broad spectrum of cardiac diseases. However, the correlation between pulmonary wedge pressure (PWP) and mitral Doppler profile has not yet been clearly defined in patients with atrial fibrillation, particularly in the presence of severe LV systolic dysfunction. The aim of this study was to evaluate the correlations between PWP and transmitral Doppler variables in patients with atrial fibrillation and chronic heart failure due to dilated cardiomyopathy. PWP and the mitral Doppler profile were simultaneously recorded in 35 consecutive heart failure patients (28 men, 7 women; mean age, 69 +/- 9 years) with severe LV dysfunction (mean ejection fraction 22% +/- 5%). Doppler measurements were averaged over 10 cardiac cycles. In addition, left atrial areas were derived from the apical 4-chamber view. Significant relations were observed between PWP and several parameters derived from the mitral flow: isovolumic relaxation time (r = -70), acceleration rate (r = 0.78), deceleration rate (r = 0.82), and deceleration time (r = -0.95). However, by stepwise multivariate analysis, deceleration time emerged as the sole independent predictor of PWP (r2 = 0.95, F = 590). The analysis led to the following equation: PWP = 51 - 0.26 (deceleration time). Our data suggest that mitral Doppler echocardiography is a useful tool for predicting PWP in heart failure patients with severe LV dysfunction even in the presence of atrial fibrillation. PMID:10080426

  11. Extra-atrial expression of the gene for atrial natriuretic factor.

    PubMed Central

    Gardner, D G; Deschepper, C F; Ganong, W F; Hane, S; Fiddes, J; Baxter, J D; Lewicki, J

    1986-01-01

    Atrial natriuretic factor (ANF) is a group of peptides, originally isolated from the cardiac atria, that have a number of important effects on blood pressure, renal function, and salt balance. In the current study, expression of the ANF gene in certain extra-atrial tissues of the rat has been examined by radioimmunoassay of extracted ANF protein and by blot-hybridization, nuclease S1 analysis, and primer-extension analysis of the ANF mRNA. ANF peptides and mRNA were detected in cardiac ventricles, lung, and pituitary gland at levels generally less than or equal to 1% those of cardiac atria. The ANF transcripts in extra-atrial tissue appear to be very similar to those synthesized in the atria. They are polyadenylylated, are equivalent in overall length (950-1050 nucleotides), and have identical 5' termini. A secondary transcription start site mapping approximately 80 base pairs upstream from the primary start site is employed in atria and to a lesser extent in other tissues. The ANF transcript is present throughout the cardiac ventricles from apex to base and in the septum as well as the ventricular free walls. The transcript is more prevalent in the left ventricle and interventricular septum than in the right ventricle. Immunocytochemistry using various anti-rat ANF antibodies localized ANF immunoreactivity to the atrial myocytes; the ventricular myocytes, particularly along the endothelial surface of the ventricular chamber; perialveolar cells in the lung; and the gonadotropin-producing cells of the pituitary. The data indicate that the capacity for ANF gene expression extends beyond atrial tissue, albeit at much reduced levels, and may suggest alternative, perhaps paraendocrine, functions for the peptide in these tissues. Images PMID:2428040

  12. Genetic Loci Associated With Atrial Fibrillation: Relation to Left Atrial Structure in the Framingham Heart Study

    PubMed Central

    Magnani, Jared W.; Yin, Xiaoyan; McManus, David D.; Chuang, Michael L.; Cheng, Susan; Lubitz, Steven A.; Arora, Garima; Manning, Warren J.; Ellinor, Patrick T.; Benjamin, Emelia J.

    2014-01-01

    Background Atrial fibrillation (AF) results in significant morbidity and mortality. Genome‐wide association studies (GWAS) have identified genetic variants associated with AF. Whether genetic variants associated with AF are also associated with atrial structure, an intermediate phenotype for AF, has had limited investigation. We sought to investigate associations between single nucleotide polymorphisms (SNPs) and atrial structure obtained by cardiovascular imaging in the Framingham Heart Study. Methods and Results We selected 11 SNPs that have been associated with AF in GWAS. We examined the SNPs' relations to cross‐sectional left atrial (LA) dimensions (determined by transthoracic echocardiography) and LA volume (determined by cardiovascular magnetic resonance [CMR]) employing linear regression. The total sample included 1555 participants with CMR LA volume (age 60±9 years, 53% women) and 6861 participants with echocardiographic LA diameter (age 48±13 years, 52% women) measured. We employed a significance threshold of P<0.0023 to account for multiple testing of the 11 SNPs and 2 LA measures. In a primary analysis, no SNPs were significantly related to the LA measures. Likewise, in secondary analyses excluding individuals with prevalent AF (n=77, CMR sample; n=105, echocardiography sample) no SNPs were related to LA volume or diameter. Conclusion In a community‐based cohort, we did not identify a statistically significant association between selected SNPs associated with AF and measures of LA anatomy. Further investigations with larger longitudinally assessed samples and a broader array of SNPs may be necessary to determine the relation between genetic loci associated with AF and atrial structure. PMID:24695651

  13. 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

  14. 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

  15. 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

  16. Apixaban and atrial fibrillation: no clear advantage.

    PubMed

    2014-02-01

    For the prevention of thromboembolic events in patients with atrial fibrillation and a high thrombotic risk, the standard treatment is warfarin, an anticoagulant. Dabigatran, a thrombin inhibitor, is the alternative when warfarin fails to maintain the INR within the therapeutic range. Patients with a moderate thrombotic risk may receive either warfarin or low-dose aspirin. Apixaban, a factor Xa inhibitor anticoagulant, has been authorised in the European Union for use in patients with non-valvular atrial fibrillation and a moderate or high risk of thrombosis. In a double-blind, randomised non-inferiority trial versus warfarin in 18 201 patients, the incidence of stroke or systemic embolism was lower in the apixaban group (average 1.3 versus 1.6 events per 100 patient-years; p = 0.01). This difference was mainly due to a lower incidence of haemorrhagic stroke and did not result in a clear decline in mortality. In addition, these results are undermined by multiple methodological flaws. Clinical evaluation included no trials comparing apixaban with dabigatran; any indirect comparison would be risky given the poor quality of the clinical assessment of both drugs in atrial fibrillation. A double-blind, randomised trial including 5598 patients compared apixaban with aspirin but provided little information on these options in patients with a moderate risk of thrombosis, as most patients were at high risk. In clinical trials, major bleeding events were less frequent with apixaban than with warfarin (average 2.1 versus 3.1 events per 100 patient-years), but they were more frequent with apixaban than with aspirin (1.4 versus 0.9 events per 100 patient-years). In 2013, there is no way of monitoring the anticoagulant activity of apixaban in routine clinical practice, and there is no antidote in case of overdose; the same is true for dabigatran. Apixaban is a substrate for various cytochrome P450 isoenzymes and for P-glycoprotein, creating a risk of multiple drug

  17. Antithrombotic and Anticoagulant Therapy for Atrial Fibrillation.

    PubMed

    Dzeshka, Mikhail S; Lip, Gregory Y H

    2016-04-01

    As atrial fibrillation (AF) substantially increases the risk of stroke and other thromboembolic events, most AF patients require appropriate antithrombotic prophylaxis. Oral anticoagulation (OAC) with either dose-adjusted vitamin K antagonists (VKAs) (eg, warfarin) or non-VKA oral anticoagulants (eg, dabigatran, apixaban, rivaroxaban) can be used for this purpose unless contraindicated. Therefore, risk assessment of stroke and bleeding is an obligatory part of AF management, and risk has to be weighed individually. Antiplatelet drugs (eg, aspirin and clopidogrel) are inferior to OAC, both alone and in combination, with a comparable risk of bleeding events. PMID:26968670

  18. Cardiometabolic risk factors and atrial fibrillation.

    PubMed

    Menezes, Arthur R; Lavie, Carl J; Dinicolantonio, James J; O'Keefe, James; Morin, Daniel P; Khatib, Sammy; Abi-Samra, Freddy M; Messerli, Franz H; Milani, Richard V

    2013-01-01

    Atrial fibrillation (AF) is the most common arrhythmia worldwide; it is a significant risk factor for stroke and embolization, and has an impact on cardiac function. Despite its impact on morbidity and mortality, our understanding of the etiology and pathophysiology of this disease process is still incomplete. Over the past several decades, there has been evidence to suggest that AF has a significant correlation with metabolic syndrome (MetS). Furthermore, AF appears to be more closely related to specific components of MetS compared with others. This article provides an overview of the various components of MetS and their impact on AF. PMID:24448257

  19. 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

  20. Science Linking Pulmonary Veins and Atrial Fibrillation.

    PubMed

    Mahida, Saagar; Sacher, Frederic; Derval, Nicolas; Berte, Benjamin; Yamashita, Seigo; Hooks, Darren; Denis, Arnaud; Amraoui, Sana; Hocini, Meleze; Haissaguerre, Michel; Jais, Pierre

    2015-05-01

    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