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Sample records for atrial flutter

  1. Electrophysiological Mechanisms of Atrial Flutter

    Directory of Open Access Journals (Sweden)

    Ching- Tai Tai

    2006-04-01

    Full Text Available Atrial flutter (AFL is a common arrhythmia in clinical practice. Several experimental models such as tricuspid regurgitation model, tricuspid ring model, sterile pericarditis model and atrial crush injury model have provided important information about reentrant circuit and can test the effect of antiarrhythmic drugs. Human atrial flutter has typical and atypical forms. Typical atrial flutter rotates around tricuspid annulus and uses the crista terminalis and sometimes sinus venosa as the boundary. The IVC-tricuspid isthmus is a slow conduction zone and the target of radiofrequency ablation. Atypical atrial flutter may arise from the right or left atrium. Right atrial flutter includes upper loop reentry, free wall reentry and figure of eight reentry. Left atrial flutter includes mitral annular atrial flutter, pulmonary vein-related atrial flutter and left septal atrial flutter. Radiofrequency ablation of the isthmus between the boundaries can eliminate these arrhythmias.

  2. Electrophysiological Mechanisms of Atrial Flutter

    Directory of Open Access Journals (Sweden)

    Ching-Tai Tai

    2009-02-01

    Full Text Available Atrial flutter (AFL is a common arrhythmia in clinical practice. Several experimental models, such as tricuspid regurgitation model, tricuspid ring model, sterile pericarditis model and atrial crush injury model, have provided important information about reentrant circuit and can test the effects of antiarrhythmic drugs. Human AFL has typical and atypical forms. Typical AFL rotates around the tricuspid annulus and uses the crista terminalis and sometimes sinus venosa as the boundary. The tricuspid isthmus is a slow conduction zone and the target of radiofrequency ablation. Atypical AFL may arise from the right or left atrium. Right AFL includes upper loop reentry, free wall reentry and figure-of-8 reentry. Left AFL includes mitral annular AFL, pulmonary vein-related AFL and left septal AFL. Radiofrequency ablation of the isthmus between the boundaries can eliminate these arrhythmias.

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

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    Kousik Krishnan

    2009-05-01

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

  4. Thromboembolic risk in atrial flutter. The FLASIEC (FLutter Atriale Società Italiana di Ecografia Cardiovascolare) multicentre study.

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    Corrado, G; Sgalambro, A; Mantero, A; Gentile, F; Gasparini, M; Bufalino, R; Morabito, A; Trocino, G; Schiavina, R; Mandorla, S; Mangia, R; Tovena, D; Savino, K; Jacopi, F; Pellegrino, E M; Agostini, F; Centonze, G; Bovenzi, F; Caprino, E; Tadeo, G; Santarone, M

    2001-06-01

    Patients with atrial flutter are believed to be at lower risk of thromboembolism than patients with atrial fibrillation. However, the incidence of atrial thrombi and the need for anticoagulation in patients with atrial flutter is not well established. A prospective observational multicentre study was undertaken to assess the frequency of atrial thrombi and spontaneous echocontrast and the prevalence for aortic complex atherosclerotic lesions in a cohort of unselected patients with atrial flutter. We evaluated 134 patients (102 male, aged 70+/-9 years); exclusion criteria were history of atrial fibrillation, rheumatic mitral valve disease and mitral mechanical prosthesis. The median of atrial flutter duration was 33 days. Twelve patients had been taking warfarin for more than 7 days. One hundred and twenty-four patients (94%) underwent a transoesophageal echocardiogram, which revealed left atrial appendage thrombi in two patients (1.6%) and right atrial thrombi in one patient (1%). At least moderate left atrial echocontrast was found in 16/124 patients (13%). Complex atherosclerotic aortic plaques were detected in 10 patients (8%). Atrial flutter conversion was attempted in 93/134 patients (69%). At the 1-month follow-up, two patients experienced a thromboembolic event following restoration of sinus rhythm. Atrial thrombi and echocontrast, and complex aortic atherosclerotic plaques are relatively uncommon in patients with atrial flutter. Post-cardioversion embolism was observed in two patients in our study population.

  5. Prevention of atrial flutter with cryoablation may be proarrhythmogenic

    DEFF Research Database (Denmark)

    Lukac, Peter; Hjortdal, Vibeke E; Pedersen, Anders K

    2007-01-01

    BACKGROUND: Atrial flutter is a serious problem after surgery for congenital heart disease. METHODS: We performed an intraoperative linear one-minute cryolesion between a right atriotomy and the tricuspid annulus to prevent atrial flutter in 17 consecutive adult patients undergoing surgery...

  6. A Large Right Atrial Myxoma Associated with Atrial Flutter Rhythm

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    Onursal Buğra

    2010-04-01

    Full Text Available A 22 year-old man presented to the emergency unit with the complaint of difficulty in breathing. In the physical exam, dyspnea and orthopnea were found. In the electocardiographic exam (ECG atrial flutter rhythm was seen. The transthoracic echocardiographic exam revealed a large atrial mass that was originating from interatrial septum. During surgery, complete surgical removal of the right atrial mass was successfully performed under moderate hypothermia. Histological investigations revealed a mass of 15 x 3 cm in diameter and the pathological examination showed that the lesion is a myxoma. Twelve months after surgical excision, clinical and chocardiographicalfollow-up showed a satisfactory exercise tolerance, sinus rhythm in ECG exam, and cardiac functions within normal limits.

  7. Caffeine and risk of atrial fibrillation or flutter

    DEFF Research Database (Denmark)

    Frost, Lars; Vestergaard, Peter

    2005-01-01

    BACKGROUND: It is not known whether the consumption of caffeine is associated with excess risk of atrial fibrillation. OBJECTIVE: We evaluated the risk of atrial fibrillation or flutter in association with daily consumption of caffeine from coffee, tea, cola, cocoa, and chocolate. DESIGN: We...... prospectively examined the association between the amount of caffeine consumed per day and the risk of atrial fibrillation or flutter among 47 949 participants (x age: 56 y) in the Danish Diet, Cancer, and Health Study. Subjects were followed in the Danish National Registry of Patients and in the Danish Civil...... Registration System. The consumption of caffeine was analyzed by quintiles with Cox proportional-hazard models. RESULTS: During follow-up (x: 5.7 y), atrial fibrillation or flutter developed in 555 subjects (373 men and 182 women). When the lowest quintile of caffeine consumption was used as a reference...

  8. Impact of dronedarone in atrial fibrillation and flutter on stroke reduction

    DEFF Research Database (Denmark)

    Christiansen, Christine Benn; Torp-Pedersen, Christian; Køber, Lars

    2010-01-01

    Dronedarone has been developed for treatment of atrial fibrillation (AF) or atrial flutter (AFL). It is an amiodarone analogue but noniodinized and without the same adverse effects as amiodarone.......Dronedarone has been developed for treatment of atrial fibrillation (AF) or atrial flutter (AFL). It is an amiodarone analogue but noniodinized and without the same adverse effects as amiodarone....

  9. Dronedarone for the treatment of atrial fibrillation and atrial flutter.

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    Maund, E; McKenna, C; Sarowar, M; Fox, D; Stevenson, M; Pepper, C; Palmer, S; Woolacott, N

    2010-10-01

    This paper presents a summary of the evidence review group (ERG) report on the clinical effectiveness and cost-effectiveness of dronedarone for the treatment of atrial fibrillation (AF) or atrial flutter based upon a review of the manufacturer's submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal process. The population considered in the submission were adult clinically stable patients with a recent history of or current non-permanent AF. Comparators were the current available anti-arrhythmic drugs: class 1c agents (flecainide and propafenone), sotalol and amiodarone. Outcomes were AF recurrence, all-cause mortality, stroke, treatment discontinuations (due to any cause or due to adverse events) and serious adverse events. The main evidence came from four phase III randomised controlled trials, direct and indirect meta-analyses from a systematic review, and a synthesis of the direct and indirect evidence using a mixed-treatment comparison. Overall, the results from the different synthesis approaches showed that the odds of AF recurrence appeared statistically significantly lower with dronedarone and other anti-arrhythmic drugs than with non-active control, and that the odds of AF recurrence are statistically significantly higher for dronedarone than for amiodarone. However, the results for outcomes of all-cause mortality, stroke and treatment discontinuations and serious adverse events were all uncertain. A discrete event simulation model was used to evaluate dronedarone versus antiarrhythmic drugs and standard therapy alone. The incremental cost-effectiveness ratio of dronedarone was relatively robust and less than 20,000 pounds per quality-adjusted life-year. Exploratory work undertaken by the ERG identified that the main drivers of cost-effectiveness were the benefits assigned to dronedarone for all-cause mortality and stroke. Dronedarone is not cost-effective relative to its comparators when

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

    DEFF Research Database (Denmark)

    Sethi, Naqash J; Feinberg, Joshua; Nielsen, Emil E

    2017-01-01

    strategies versus rate control strategies for atrial fibrillation and atrial flutter. METHODS: We searched CENTRAL, MEDLINE, Embase, LILACS, Web of Science, BIOSIS, Google Scholar, clinicaltrials.gov, TRIP, EU-CTR, Chi-CTR, and ICTRP for eligible trials comparing any rhythm control strategy with any rate...

  11. [Antithrombotic therapy in patients with atrial flutter before planned cardioversion].

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    М'якінькова, Людмила О; Тесленко, Юрій В; Пустовойт, Ганна Л; Ярмола, Тетяна І; Циганенко, Ірина В

    atrium flutter and fibrillation are the heart rhythm disorders that increase the risk of life-dangerous complications, e.g. cardioembolic stroke, pulmonary embolism. Recommendations for managing patients with atrial fibrillation - atrial flutter, with paroxysm duration over 48 hours, demand anticoagulant therapy. Oral anticoagulants, which are the antagonists of K vitamin (Varpharin) and the new oral anticoagulants (Rivaroxaban), are used during the per-manipulative procedure of patients with atrial flutter before restoring the sinus rhythm with transesophageal cardiac pacing. the present investigation aims to compare efficiency and safety of Varpharin and Rivaaroxaban in treatment patients with atrial flutter before planned cardioversion with transesophageal heart pacing. Varpharin (control group) - in doses equivalent for reaching the target МНВ - or Rivaroxaban (research group), 20 mg., were prescribed to 42 patients with coronary heart disease, concomitant arterial hypertension, and non-valvular paroxysm of atrial flutter with more than 48-hour duration, divided into two groups. There was held the general clinical, echocardioscopy examination. Thrombotic Risk Factor Assessment was made according to the CHA2DS2-VASc scale, Hemorrhagic Risk Factor Assessment was performed according to the HAS-BLED scale, and clinical symptoms assessment was made according to the EHRA scale. The heart rhythm was restored with the transesophageal heart pacing. the per-manipulative procedure of the patients of research group (21 days were suggested according to the guidelines) shortened, unlike the patients of control group (the period of target МНВ selection had made 30,76±0,62days), the reduction of the symptoms severity by EHRA was considered in dynamics. According to the results of transesophageal heart pacing, the heart rhythm of 15 research group patients restored, and 6 research group patients had atrial fibrillation. Among the patients of the control group, 6 had

  12. Radiofrequency catheter ablation for atrial flutter following orthotopic heart transplantation

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    Pitt, M; Bonser, R; Griffith, M

    1998-01-01

    A 26 year old woman with a diagnosis of limb girdle muscular dystrophy and peripartum cardiomyopathy underwent orthotopic heart transplantation using standard atrial anastomoses. Recurrent atrial flutter was demonstrated in the absence of histological evidence of cellular rejection. Radiofrequency ablation of the flutter circuit was successfully performed allowing the avoidance of long term antiarrhythmic therapy. Ten weeks following ablation and cessation of amiodarone, presyncopal symptoms were found, associated with daytime and nocturnal sinus pauses of 2.9 seconds and 4.2 seconds, respectively. There was no evidence of AV node conduction impairment. In view of the continued absence of cellular rejection and the evident denervated state of the heart, the pauses reflected significant donor sinus node dysfunction; therefore, an AAIR permanent pacing system was implanted. At the time of pacemaker implantation atrial pacing at 150 beats/min did not produce significant PR interval prolongation or AV block. This case serves to advise rigorous follow up in such patients to continue to seek evidence of sinus node dysfunction potentially requiring permanent pacemaker implantation.

 Keywords: heart transplantation;  atrial flutter;  radiofrequency catheter ablation PMID:9616353

  13. Atrial flutter complicating severe leptospirosis: a case report

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    Francisco Theogenes Macêdo Silva

    2013-04-01

    Full Text Available Cardiac disturbances are relatively common and electrocardiographic abnormalities may be found in more than 70% of patients with leptospirosis. We report the case of a 68 year-old male with severe leptospirosis who developed atrial flutter. Effective treatment was done with amiodarone. The patient became clinical stable, with complete recovery. Rigorous clinical observation and continuous electrocardiogram (ECG monitoring may facilitate the identification of rhythm disorders, and thus prevent a probable fatal outcome, in severe cases of leptospirosis.

  14. The occurrence and prognostic significance of atrial fibrillation/-flutter following acute myocardial infarction. TRACE Study group. TRAndolapril Cardiac Evalution

    DEFF Research Database (Denmark)

    Pedersen, O D; Bagger, H; Køber, L

    1999-01-01

    AIMS: To investigate the occurrence and prognostic significance of atrial fibrillation/-flutter following acute myocardial infarction. METHODS AND RESULTS: The occurrence and prognostic significance of atrial fibrillation/-flutter were studied in 6676 consecutive patients with acute myocardial in...

  15. Efficacy and safety of vernakalant in patients with atrial flutter

    DEFF Research Database (Denmark)

    Camm, A John; Toft, Egon; Torp-Pedersen, Christian

    2012-01-01

    AIMS: Vernakalant is a novel, relatively atrial-selective antiarrhythmic agent for conversion of atrial fibrillation (AF) to sinus rhythm. This study examined the safety and efficacy of vernakalant in converting atrial flutter (AFL) to sinus rhythm. METHODS AND RESULTS: This was a phase 2....... The primary efficacy outcome was the proportion of patients who had treatment-induced conversion of AFL to sinus rhythm for a minimum duration of 1 min within 90 min after the start of the first infusion. No patient in the placebo group met the primary outcome. Only one patient receiving vernakalant (1 of 39......, 3%) converted to sinus rhythm. A reduced mean absolute ventricular response rate occurred within 50 min in patients receiving vernakalant (mean change from baseline -8.2 b.p.m.) vs. patients receiving placebo (-0.2 b.p.m.) (P = 0.037). A post-hoc analysis revealed that vernakalant increased AFL...

  16. Long-term outcome of electrical cardioversion in patients with chronic atrial flutter

    NARCIS (Netherlands)

    Crijns, HJGM; VanGelder, IC; Tieleman, RG; Brugemann, J; DeKam, PJ; Gosselink, ATM; BinkBoelkens, MTE; Lie, KI

    Objective-To determine she long-term outcome of serial electrical cardioversion therapy in patients with chronic atrial flutter. Design-Prospective study, case series. Setting-University hospital. Patients-50 consecutive patients with chronic (> 24 hours) atrial flutter without a previous relapse on

  17. Clinical Differences between Subtypes of Atrial Fibrillation and Flutter: Cross-Sectional Registry of 407 Patients

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    Almeida, Eduardo Dytz; Guimarães, Raphael Boesche; Stephan, Laura Siga; Medeiros, Alexandre Kreling; Foltz, Katia; Santanna, Roberto Tofani; Pires, Leonardo Martins; Kruse, Marcelo Lapa; de Lima, Gustavo Glotz; Leiria, Tiago Luiz Luz

    2015-01-01

    Introduction Atrial fibrillation and atrial flutter account for one third of hospitalizations due to arrhythmias, determining great social and economic impacts. In Brazil, data on hospital care of these patients is scarce. Objective To investigate the arrhythmia subtype of atrial fibrillation and flutter patients in the emergency setting and compare the clinical profile, thromboembolic risk and anticoagulants use. Methods Cross-sectional retrospective study, with data collection from medical records of every patient treated for atrial fibrillation and flutter in the emergency department of Instituto de Cardiologia do Rio Grande do Sul during the first trimester of 2012. Results We included 407 patients (356 had atrial fibrillation and 51 had flutter). Patients with paroxysmal atrial fibrillation were in average 5 years younger than those with persistent atrial fibrillation. Compared to paroxysmal atrial fibrillation patients, those with persistent atrial fibrillation and flutter had larger atrial diameter (48.6 ± 7.2 vs. 47.2 ± 6.2 vs. 42.3 ± 6.4; p < 0.01) and lower left ventricular ejection fraction (66.8 ± 11 vs. 53.9 ± 17 vs. 57.4 ± 16; p < 0.01). The prevalence of stroke and heart failure was higher in persistent atrial fibrillation and flutter patients. Those with paroxysmal atrial fibrillation and flutter had higher prevalence of CHADS2 score of zero when compared to those with persistent atrial fibrillation (27.8% vs. 18% vs. 4.9%; p < 0.01). The prevalence of anticoagulation in patients with CHA2DS2-Vasc ≤ 2 was 40%. Conclusions The population in our registry was similar in its comorbidities and demographic profile to those of North American and European registries. Despite the high thromboembolic risk, the use of anticoagulants was low, revealing difficulties for incorporating guideline recommendations. Public health strategies should be adopted in order to improve these rates. PMID:26016782

  18. Long-term endurance sport is a risk factor for development of lone atrial flutter.

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    Claessen, Guido; Colyn, Erwin; La Gerche, André; Koopman, Pieter; Alzand, Becker; Garweg, Christophe; Willems, Rik; Nuyens, Dieter; Heidbuchel, Hein

    2011-06-01

    To evaluate whether in a population of patients with 'lone atrial flutter', the proportion of those engaged in long-term endurance sports is higher than that observed in the general population. An age and sex-matched retrospective case-control study. A database with 638 consecutive patients who underwent ablation for atrial flutter at the University of Leuven. Sixty-one patients (55 men, 90%) fitted the inclusion criteria of 'lone atrial flutter', ie, aged 65 years or less, without documented atrial fibrillation and without identifiable underlying disease (including hypertension). Sex, age and inclusion criteria-matched controls, two for each flutter patient, were selected in a general practice in the same geographical region. Sports activity was evaluated by detailed questionnaires, which were available in 58 flutter patients (95%). A transthoracic echocardiogram was performed in all lone flutter patients. Types of sports, number of years of participation and average number of hours per week. The proportion of regular sportsmen (≥3 h of sports practice per week) among patients with lone atrial flutter was significantly higher than that observed in the general population (50% vs 17%; psports (participation in cycling, running or swimming for ≥3 h/week) was also significantly higher in lone flutter patients than in controls (31% vs 8%; p=0.0003). Those flutter patients performing endurance sports had a larger left atrium than non-sportsmen (p=0.04, by one-way analysis of variance). A history of endurance sports and subsequent left atrial remodelling may be a risk factor for the development of atrial flutter.

  19. Intermittent changing axis deviation with intermittent left anterior hemiblock during atrial flutter with subclinical hyperthyroidism.

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    Patanè, Salvatore; Marte, Filippo

    2009-06-26

    Subclinical hyperthyroidism is an increasingly recognized entity that is defined as a normal serum free thyroxine and free triiodothyronine levels with a thyroid-stimulating hormone level suppressed below the normal range and usually undetectable. It has been reported that subclinical hyperthyroidism is not associated with CHD or mortality from cardiovascular causes but it is usually associated with a higher heart rate and a higher risk of supraventricular arrhythmias including atrial fibrillation and atrial flutter. Intermittent changing axis deviation during atrial fibrillation has also rarely been reported. We present a case of intermittent changing axis deviation with intermittent left anterior hemiblock in a 59-year-old Italian man with atrial flutter and subclinical hyperthyroidism. To our knowledge, this is the first report of intermittent changing axis deviation with intermittent left anterior hemiblock in a patient with atrial flutter.

  20. The occurrence and prognostic significance of atrial fibrillation/-flutter following acute myocardial infarction. TRACE Study group. TRAndolapril Cardiac Evalution.

    Science.gov (United States)

    Pedersen, O D; Bagger, H; Køber, L; Torp-Pedersen, C

    1999-05-01

    To investigate the occurrence and prognostic significance of atrial fibrillation/-flutter following acute myocardial infarction. The occurrence and prognostic significance of atrial fibrillation/-flutter were studied in 6676 consecutive patients with acute myocardial infarction screened in 27 centres in Denmark for inclusion into the TRAndolapril Cardiac Evaluation (TRACE) study. Information about occurrence of atrial fibrillation/-flutter during hospitalization was prospectively collected for the following three periods: day 1-2, day 3-4 and from day 5 until discharge. A total of 1395 patients (21%) suffered from atrial fibrillation/-flutter in one or more of the specified periods during hospitalization. Patients with atrial fibrillation/-flutter were significantly older, a significantly greater proportion were women, left ventricular systolic dysfunction was more extensive, thrombolytic therapy was received less frequently, and anterior Q wave myocardial infarction was experienced more frequently than patients without atrial fibrillation/-flutter. History of acute myocardial infarction and/or angina pectoris was similar in patients with and without atrial fibrillation/-flutter, whereas significantly more patients with atrial fibrillation/-flutter had a history of hypertension, congestive heart failure, diabetes mellitus, pulmonary disease and stroke. The unadjusted in-hospital mortality rate was significantly higher in patients with atrial fibrillation/-flutter in one or more of the specified periods during hospitalization (18%) than in patients without atrial fibrillation/-flutter (9%), P<0.001. After adjustment for baseline characteristics, the presence of atrial fibrillation/-flutter was still associated with increased in-hospital mortality; odds ratio=1.5 (95% Cl: 1.2-1.8), P<0.001. In patients surviving hospitalization, the unadjusted 5-year mortality rate was also significantly higher in patients suffering from atrial fibrillation/-flutter (56%) than in

  1. Pharmacologic versus direct-current electrical cardioversion of atrial flutter and fibrillation

    NARCIS (Netherlands)

    Van Gelder, IC; Tuinenburg, AE; Schoonderwoerd, BS; Tieleman, RG; Crijns, HJGM

    1999-01-01

    Conversion of atrial flutter and atrial fibrillation (AF) can be achieved by either pharmacologic or direct-current (DC) electrical cardioversion. DC electrical cardioversion is more effective and restores sinus rhythm instantaneously; however, general anesthesia is necessary, which can cause severe

  2. Risk of Atrial Fibrillation or Flutter Associated with Periodontitis: A Nationwide, Population-Based, Cohort Study.

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    Der-Yuan Chen

    Full Text Available To investigate the risk of atrial fibrillation or atrial flutter in patients with periodontitis (PD in comparison with individuals without PD.We used the 1999-2010 Taiwanese National Health Insurance Research Database to identify cases of PD in the year 2000 matching (1:1 with persons without PD during 1999-2000 according to sex and individual age as the control group. Using Cox proportional regression analysis adjusting for potential confounders, including age, sex, and comorbidities at baseline, and average annual number of ambulatory visits and dental scaling frequency during the follow-up period, we estimated hazard ratios (HRs with 95% confidence intervals (CIs to examine the risk of atrial fibrillation or flutter in PD patients in comparison with the control group. Subgroup analyses according to age, gender, or comorbidities were conducted to study the robustness of the association and investigate possible interaction effects.We enrolled 393,745 patients with PD and 393,745 non-PD individuals. The incidence rates of atrial fibrillation or flutter were 200 per 105 years among the PD group and 181 per 105 years in the non-PD group (incidence rate ratio, 1.10; 95% CI, 1.06-1.14. After adjusting for potential confounders, we found an increased risk of atrial fibrillation or flutter in the PD group compared with the non-PD group (HR, 1.31; 95% CI, 1.25-1.36. The greater risk of atrial fibrillation or flutter in the PD group remained significant across all disease subgroups except hyperthyroidism and sleep apnea.The present study results indicate an increased risk of atrial fibrillation or flutter in patients with PD. Lack of individual information about alcohol consumption, obesity, and tobacco use was a major limitation.

  3. n-3 Fatty acids consumed from fish and risk of atrial fibrillation or flutter

    DEFF Research Database (Denmark)

    Frost, Lars; Vestergaard, Peter

    2005-01-01

    of 47 949 participants (mean age: 56 y) in the Danish Diet, Cancer, and Health Study, we investigated the relation between the consumption of n-3 fatty acids from fish estimated from a detailed semiquantitative food questionnaire and risk of atrial fibrillation or flutter. The subjects were followed up......BACKGROUND: Experimental studies have shown that n-3 polyunsaturated fatty acids in fish may have antiarrhythmic properties. OBJECTIVE: We examined the association between consumption of n-3 fatty acids from fish and risk of atrial fibrillation or flutter. DESIGN: In a prospective cohort study...... in the Danish National Registry of Patients for the occurrence of atrial fibrillation or flutter and in the Danish Civil Registration System (vital status and emigration). The consumption of n-3 fatty acids from fish was analyzed as sex-specific quintiles with the use of Cox proportional hazards models. RESULTS...

  4. Mitral valve prolapse, atrial flutter, and syncope in a young female patient.

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    Ismajli, Jehona; Shabani, Xhevahire; Manaj, Rexhep; Emini, Merita; Bajraktari, Gani

    2006-11-01

    The syndrome of mitral valve prolapse (MVP) is the most common form of valvular heart disease. The case of a 16-year-old girl with mitral valve prolapse, atrial flutter and syncope is presented. The patient was admitted to the clinic complaining of atypical chest pain, palpitations, breathlessness at physical efforts, fatigue, and a feeling of fogginess. Electrocardiogram showed the presence of the common-type atrial flutter with 3:1 ventricular responses. Echocardiography showed mitral valve prolapse with mild mitral regurgitation. The patient reported to have had these symptoms for about nine months. She was not aware of heart disease before. A young female patient with combined mitral valve prolapse, atrial flutter, and syncope is presented.

  5. Frequency and significance of right atrial appendage thrombi in patients with persistent atrial fibrillation or atrial flutter.

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    Cresti, Alberto; García-Fernández, Miguel Angel; Miracapillo, Gennaro; Picchi, Andrea; Cesareo, Francesca; Guerrini, Francesco; Severi, Silva

    2014-11-01

    Atrial fibrillation (AF) and atrial flutter (AFL) are strong atrial thrombosis (THR) risk factors. In recent-onset tachyarrhythmias, the incidence of left atrial appendage (LAA) THR, detected by transesophageal echocardiography (TEE), has been widely studied, ranging from 6% to 18% (AF) and 4% to 11% (AFL). On the contrary, few studies have assessed right atrial appendage (RAA) THR, and there is no information on the relation between the RAA flow characteristics and the presence of RAA THR. The aims of this study were to evaluate the incidence of RAA THR in a population of patients undergoing TEE-guided cardioversion for recent-onset atrial tachyarrhythmias and to analyze RAA Doppler flow and its relation to thrombus formation. From 1998 to 2012, patients admitted to the emergency department for persistent, non-self-terminating atrial tachyarrhythmia lasting >2 days who gave informed consent for TEE-guided cardioversion were prospectively enrolled in the study. Among 1,042 patients, complete anatomic and functional studies of the LAA and RAA were feasible in 983 (AF, n = 810 [23%]; AFL, n = 173 [5%]). The presence of RAA and LAA THR, appendage emptying velocities, and the presence of severe spontaneous echocardiographic contrast were studied. The overall incidence of atrial THR was 9.7% (96 of 983). The incidence of THR was 9.3% (91 of 983) in the LAA and 0.73% (seven of 983) in the RAA (P thrombi are significantly less frequent than LAA thrombi but may reach large dimensions. Multiplane TEE allows RAA morphologic and functional assessment. Before TEE-guided cardioversion, both the LAA and the RAA must be routinely studied. Copyright © 2014 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

  6. Mechanisms of atrial flutter following epicardial high intensity focused ultrasound left atrial ablative procedures during concomitant cardiac surgery

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    Ahmed El-Damaty

    2014-12-01

    Conclusions: Re-entrant atrial flutter post-HIFU epicor Maze is caused by slow conduction at entry and exit sites from the otherwise isolated posterior LA wall. In both cases, gaps were found close to the LSPV and RIPV which may reflect difficulty in achieving proper contact between the HIFU device and the left atrial wall at these sites. These gaps are amenable to catheter ablation.

  7. Atrial flutter in a patient with atrial septal defect and anomalous venous drainage: unusual approach for ablation.

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    Roca-Luque, Ivo; Rivas, Nuria; Dos, Laura; Francisco, Jaume; Pérez-Rodon, Jordi; Pijuan, Antònia; Garcia-Dorado, David; Moya, Àngel

    2017-07-01

    Atrial flutter ablation in CHD (Congenital Heart Disease) patients is a challenging procedure because of the possibility of multiple circuits. Electroanatomical mapping and pacing maneuvers are crucial to determine critical isthmus. Moreover, vascular abnormalities and residual cardiac defects need to be known before the ablation to decide the better strategy for ablation.

  8. Work related physical activity and risk of a hospital discharge diagnosis of atrial fibrillation or flutter

    DEFF Research Database (Denmark)

    Frost, L; Frost, P; Vestergaard, P

    2005-01-01

    BACKGROUND AND AIMS: Excessive sporting activities have been associated with risk of atrial fibrillation. To study if work related physical activity also confers risk of atrial fibrillation or flutter, the association between work related physical strain and the risk of a hospital discharge......, Cancer, and Health Study. The physical strain during working hours was categorised as sedentary, light, or heavy, and analysed using proportional hazard models. Subjects were followed up in the Danish National Registry of Patients and in the Danish Civil Registration System. RESULTS: During follow up...... of atrial fibrillation or flutter associated with sedentary work in a standing position, light workload, or heavy workload in men or women. CONCLUSION: No evidence was found of an association between physical activities during working hours and risk of a hospital discharge diagnosis of atrial fibrillation...

  9. 1C-INDUCED ATRIAL FLUTTER IN A PATIENT WITH WPW SYNDROME: CASE REPORT AND REVIEW

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    R. R. Mamatkazina

    2012-01-01

    Full Text Available The clinical case of a rare proarrhythmic effect of antiarrhythmic drugs with a poor prognosis (medication-induced atrial flutter in a patient with "malignant" Kent’s bundle is presented. Radiofrequency ablation (RFA is the most justified treatment method in patients with WPW-syndrome and "malignant" Kent’s bundle. RFA in descripted case has been postponed due to technical reasons. While waiting for RFA and after consideration of the potential risks and benefits the decision to use antiarrhythmic drugs to block the additional bundle was made. Paroxysm of broad-complex tachycardia developed on the third day of the treatment. It was regarded as a paroxysm of atrial fibrillation/flutter in the patient with WPW syndrome induced by taking antiarrhythmic drugs class 1C (allapinine. Review of the literature on the atrial fibrillation induced by antiarrhythmic of 1C class, and association of atrial fibrillation with WPW-syndrome is presented.

  10. 1C-INDUCED ATRIAL FLUTTER IN A PATIENT WITH WPW SYNDROME: CASE REPORT AND REVIEW

    Directory of Open Access Journals (Sweden)

    R. R. Mamatkazina

    2015-12-01

    Full Text Available The clinical case of a rare proarrhythmic effect of antiarrhythmic drugs with a poor prognosis (medication-induced atrial flutter in a patient with "malignant" Kent’s bundle is presented. Radiofrequency ablation (RFA is the most justified treatment method in patients with WPW-syndrome and "malignant" Kent’s bundle. RFA in descripted case has been postponed due to technical reasons. While waiting for RFA and after consideration of the potential risks and benefits the decision to use antiarrhythmic drugs to block the additional bundle was made. Paroxysm of broad-complex tachycardia developed on the third day of the treatment. It was regarded as a paroxysm of atrial fibrillation/flutter in the patient with WPW syndrome induced by taking antiarrhythmic drugs class 1C (allapinine. Review of the literature on the atrial fibrillation induced by antiarrhythmic of 1C class, and association of atrial fibrillation with WPW-syndrome is presented.

  11. Low energy biphasic cardioversion of atrial flutter: results from a pilot trial.

    Science.gov (United States)

    Mortensen, Kai; Aydin, Muhammet Ali; Schwemer, Tjark F; Ventura, Rodolfo; Reppel, Michael; Bode, Frank; Mletzko, Ralph; Schunkert, Heribert; Risius, Tim

    2010-11-19

    A pilot study was performed to determine the efficacy of low energy biphasic external cardioversion in common type atrial flutter. In the majority of patients (70%) successful cardioversion was achieved with low energy levels of 20 or 30 J; however a considerable number of patients (15%) were initially cardioverted to atrial fibrillation, needing an additional cardioversion with an even higher energy level. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  12. Atrial flutter ablation in a case of diuretic resistant constrictive pericarditis

    Directory of Open Access Journals (Sweden)

    James F. Pittaway

    2015-07-01

    This is the first reported case of symptomatic improvement in a patient with constrictive pericarditis and persistent atrial flutter with targeted treatment of the dysrhythmia. This offers a possible short-term palliation option in a group of patients where definitive surgical management carries too high a risk.

  13. Cavotricuspid isthmus mapping to assess bidirectional block during common atrial flutter radiofrequency ablation.

    Science.gov (United States)

    Chen, J; de Chillou, C; Basiouny, T; Sadoul, N; Filho, J D; Magnin-Poull, I; Messier, M; Aliot, E

    We sought to compare published methods to an alternative approach ascertaining cavotricuspid isthmus (CTI) block during atrial flutter ablation. In 39 consecutive patients who underwent an atrial flutter ablation procedure, a 24-pole mapping catheter was positioned so that 2 adjacent dipoles were bracketing the targeted CTI line of block (LOB), with proximal dipoles lateral to the LOB and distal dipoles in the coronary sinus. Two pacing sites were lateral (positions A and B) and 2 were septal (positions C and D) to the LOB, with locations A and D closest to the LOB. A resulting CTI block was accepted when 3 criteria were fulfilled: (1) complete reversal of the right atrial depolarization on the 24-pole catheter when pacing in the coronary sinus, (2) conduction delays from A to D greater than from B to D, and (3) conduction delays from D to A greater than from C to A. A successful CTI block was obtained in all patients. Before CTI block was obtained, a progressive CTI conduction delay was observed in 11 patients (28.2%). During the procedure, the 3 criteria defined above were either all present or all absent. This study establishes that reversal of the atrial depolarization sequence up to the LOB is a definitive and mandatory criteria of successful atrial flutter ablation.

  14. An Approach to Catheter Ablation of Cavotricuspid Isthmus Dependent Atrial Flutter

    Directory of Open Access Journals (Sweden)

    Mark D O’Neill

    2006-04-01

    Full Text Available Much of our understanding of the mechanisms of macro re-entrant atrial tachycardia comes from study of cavotricuspid isthmus (CTI dependent atrial flutter. In the majority of cases, the diagnosis can be made from simple analysis of the surface ECG. Endocardial mapping during tachycardia allows confirmation of the macro re-entrant circuit within the right atrium while, at the same time, permitting curative catheter ablation targeting the critical isthmus of tissue located between the tricuspid annulus and the inferior vena cava. The procedure is short, safe and by demonstration of an electrophysiological endpoint - bidirectional conduction block across the CTI - is associated with an excellent outcome following ablation. It is now fair to say that catheter ablation should be considered as a first line therapy for patients with documented CTI-dependent atrial flutter.

  15. Successful treatment of atrial flutter by repeated intraperitoneal and intra-amniotic injections of amiodarone in a fetus with hydrops.

    Science.gov (United States)

    Lin, Pei-Hsuan; Wu, Hsin-Hung; Tsai, Horng-Der; Hsieh, Charles Tsung-Che

    2016-06-01

    We report a case of nonimmune hydrops fetalis caused by atrial flutter, which was successfully treated by intraperitoneal and intra-amniotic injections of amiodarone. A 27-year-old woman presented at 30 weeks of pregnancy with hydrops fetalis caused by a fetal atrial flutter. As the transplacental passage of antiarrhythmic agents is impaired in hydrops fetalis, we chose direct treatment using fetal intraperitoneal and intra-amniotic injections (75-300 mg) of amiodarone. We managed to successfully convert the fetal atrial flutter to normal sinus rhythm. The woman delivered a live female baby at 33 weeks of gestation with normal sinus rhythm and neurological development. Intrauterine antiarrhythmic treatment can reduce perinatal morbidity and mortality. This report suggests that direct fetal therapy using intraperitoneal or intra-amniotic injections of amiodarone constitutes an effective treatment for atrial flutter in cases of hydrops fetalis. Copyright © 2016. Published by Elsevier B.V.

  16. Electrophysiological Features of Atrial Flutter in Cardiac Sarcoidosis: A Report of Two Cases

    Directory of Open Access Journals (Sweden)

    Narayanan Namboodiri, MD

    2012-11-01

    Full Text Available We report two cases of systemic sarcoidosis with atrial flutter as the clinical manifestation. In one patient, who had symptoms of shorter duration, the arrhythmia was no longer inducible after a course of glucocorticoid therapy. Electroanatomical mapping in the other case revealed patchy fibrosis of the left atrial myocardium and multiple macro-reentrant circuits. Sinus rhythm could be restored with ablation of these reentrant circuits. To our knowledge, this is the first report on the demonstration of atrial scarring in a patient with sarcoidosis using 3-D electroanatomical mapping. These two cases illustrate that the inflammation of atrial myocardium is the primary mechanism of atrial arrhythmias in patients with cardiac sarcoidosis.

  17. The efficacy of pad placement for electrical cardioversion of atrial fibrillation/flutter: a systematic review.

    Science.gov (United States)

    Kirkland, Scott; Stiell, Ian; AlShawabkeh, Tariq; Campbell, Sandy; Dickinson, Garth; Rowe, Brian H

    2014-07-01

    Electrical cardioversion is commonly used to treat patients with atrial fibrillation and atrial flutter to restore normal sinus rhythm. There has been considerable debate as to whether the electrode placement affects the efficacy of electrical cardioversion. The objective of this study was to examine the effectiveness of anteroposterior (A-P) versus anterolateral (A-L) electrode placement to restore normal sinus rhythm. A search of eight electronic databases, including Medline, EMBASE, CINAHL, and Cochrane was completed. Grey literature (hand-searching, Google, and SCOPUS) searching was also conducted. Studies were included if they were controlled clinical trials comparing the effectiveness of A-P versus A-L pad placement to restore normal sinus rhythm in adult patients with atrial fibrillation and flutter. Two independent reviewers judged study relevance, inclusion, and quality (e.g., risk of bias). Individual and pooled statistics were calculated as relative risks (RRs) with 95% confidence intervals (CIs) using a random-effects model, and heterogeneity (I(2) ) was reported. From 788 citations, 13 studies were included; seven involved monophasic, five involved biphasic, and one analyzed both waveform devices. The included studies tended to report cumulative success rates to restoring normal sinus rhythm after one to five sequential shocks of increasing energy; the number of shocks and energy used differed among studies. The risk of bias of the studies was "unclear." After the first shock, pad placement was not associated with an increased likelihood of restoring normal sinus rhythm (RR = 0.88; 95% CI = 0.73 to 1.06); however, heterogeneity was high (I(2) = 63%). Subgroup comparisons revealed that the A-L position was more effective (RR = 0.77; 95% CI = 0.59 to 1.00) at restoring normal sinus rhythm when using biphasic shocks (comparison p = 0.04). Overall, the pooled results failed to identify a difference between A-P and A-L pad placement in restoring normal

  18. Neonatal atrial flutter after insertion of an intracardiac umbilical venous catheter

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    Marcos Moura de Almeida

    2016-03-01

    Full Text Available Abstract Objective: To describe a case of neonatal atrial flutter after the insertion of an intracardiac umbilical venous catheter, reporting the clinical presentation and reviewing the literature on this subject. Case description: A late-preterm newborn, born at 35 weeks of gestational age to a diabetic mother and large for gestational age, with respiratory distress and rule-out sepsis, required an umbilical venous access. After the insertion of the umbilical venous catheter, the patient presented with tachycardia. Chest radiography showed that the catheter was placed in the position that corresponds to the left atrium, and traction was applied. The patient persisted with tachycardia, and an electrocardiogram showed atrial flutter. As the patient was hemodynamically unstable, electric cardioversion was successfully applied. Comments: The association between atrial arrhythmias and misplaced umbilical catheters has been described in the literature, but in this case, it is noteworthy that the patient was an infant born to a diabetic mother, which consists in another risk factor for heart arrhythmias. Isolated atrial flutter is a rare tachyarrhythmia in the neonatal period and its identification is essential to establish early treatment and prevent systemic complications and even death.

  19. Noninvasive Imaging of Human Atrial Activation during Atrial Flutter and Normal Rhythm from Body Surface Potential Maps.

    Science.gov (United States)

    Zhou, Zhaoye; Jin, Qi; Yu, Long; Wu, Liqun; He, Bin

    2016-01-01

    Knowledge of atrial electrophysiological properties is crucial for clinical intervention of atrial arrhythmias and the investigation of the underlying mechanism. This study aims to evaluate the feasibility of a novel noninvasive cardiac electrical imaging technique in imaging bi-atrial activation sequences from body surface potential maps (BSPMs). The study includes 7 subjects, with 3 atrial flutter patients, and 4 healthy subjects with normal atrial activations. The subject-specific heart-torso geometries were obtained from MRI/CT images. The equivalent current densities were reconstructed from 208-channel BSPMs by solving the inverse problem using individual heart-torso geometry models. The activation times were estimated from the time instant corresponding to the highest peak in the time course of the equivalent current densities. To evaluate the performance, a total of 32 cycles of atrial flutter were analyzed. The imaged activation maps obtained from single beats were compared with the average maps and the activation maps measured from CARTO, by using correlation coefficient (CC) and relative error (RE). The cardiac electrical imaging technique is capable of imaging both focal and reentrant activations. The imaged activation maps for normal atrial activations are consistent with findings from isolated human hearts. Activation maps for isthmus-dependent counterclockwise reentry were reconstructed on three patients with typical atrial flutter. The method was capable of imaging macro counterclockwise reentrant loop in the right atrium and showed inter-atria electrical conduction through coronary sinus. The imaged activation sequences obtained from single beats showed good correlation with both the average activation maps (CC = 0.91±0.03, RE = 0.29±0.05) and the clinical endocardial findings using CARTO (CC = 0.70±0.04, RE = 0.42±0.05). The noninvasive cardiac electrical imaging technique is able to reconstruct complex atrial reentrant activations and focal

  20. Radiofrequency catheter ablation in patients with symptomatic atrial flutter/tachycardia after orthotopic heart transplantation.

    Science.gov (United States)

    Li, Yi-gang; Grönefeld, Gerian; Israel, Carsten; Lu, Shang-biao; Wang, Qun-shan; Hohnloser, Stefan H

    2006-12-20

    Atrial tachycardia or flutter is common in patients after orthotopic heart transplantation. Radiofrequency catheter ablation to treat this arrhythmia has not been well defined in this setting. This study was conducted to assess the incidence of various symptomatic atrial arrhythmias and the efficacy and safety of radiofrequency catheter ablation in these patients. Electrophysiological study and catheter ablation were performed in patients with symptomatic tachyarrhythmia. One Halo catheter with 20 poles was positioned around the tricuspid annulus of the donor right atrium, or positioned around the surgical anastomosis when it is necessary. Three quadripolar electrode catheters were inserted via the right or left femoral vein and positioned in the recipient atrium, the bundle of His position, the coronary sinus. Programmed atrial stimulation and burst pacing were performed to prove electrical conduction between the recipient and the donor atria and to induce atrial arrhythmias. Out of 55 consecutive heart transplantation patients, 6 males [(58 +/- 12) years] developed symptomatic tachycardias at a mean of (5 +/- 4) years after heart transplantation. Electrical propagation through the suture line between the recipient and the donor atrium was demonstrated during atrial flutter or during recipient atrium and donor atrium pacing in 2 patients. By mapping around the suture line, the earliest fragmented electrogram of donor atrium was assessed. This electrical connection was successfully ablated in the anterior lateral atrium in both patients. There was no electrical propagation through the suture line in the other 4 patients. Two had typical atrial flutter in the donor atrium which was successfully ablated by completing a linear ablation between the tricuspid annulus and the inferior vena cava. Two patients had atrial tachycardia which was ablated in the anterior septal and lateral donor atrium. There were no procedure-related complications. Patients were free of

  1. Safety and Efficacy of Dronedarone in the Treatment of Atrial Fibrillation/Flutter

    OpenAIRE

    Naccarelli, Gerald V; Wolbrette, Deborah L.; Vadim Levin; Soraya Samii; Banchs, Javier E.; Erica Penny-Peterson; Gonzalez, Mario D.

    2011-01-01

    Dronedarone is an amiodarone analog but differs structurally from amiodarone in that the iodine moiety was removed and a methane-sulfonyl group was added. These modifications reduced thyroid and other end-organ adverse effects and makes dronedarone less lipophilic, shortening its half-life. Dronedarone has been shown to prevent atrial fibrillation/flutter (AF/AFl) recurrences in several multi-center trials. In addition to its rhythm control properties, dronedarone has rate control properties ...

  2. Prevalence and electrophysiological characteristics of typical atrial flutter in patients with atrial fibrillation and chronic obstructive pulmonary disease.

    Science.gov (United States)

    Hayashi, Takekuni; Fukamizu, Seiji; Hojo, Rintaro; Komiyama, Kota; Tanabe, Yasuhiro; Tejima, Tamotsu; Nishizaki, Mitsuhiro; Hiraoka, Masayasu; Ako, Junya; Momomura, Shin-Ichi; Sakurada, Harumizu

    2013-12-01

    Chronic obstructive pulmonary disease (COPD) is one of the important underlying diseases of atrial fibrillation (AF). However, the prevalence and electrophysiological characteristics of typical atrial flutter (AFL) in patients with AF and COPD remain unknown. The purpose of the present study was to investigate those characteristics. We investigated 181 consecutive patients who underwent catheter ablation of AF. Twenty-eight patients were diagnosed with COPD according to the Global Initiatives for Chronic Obstructive Lung Disease (GOLD) criteria. Forty patients with no lung disease served as a control group. We analysed the electrophysiological characteristics in these groups. Typical AFL was more common in the COPD group (19/28, 68%) than in the non-COPD group (13/40, 33%; P = 0.006). The prevalence of AFL increased with the severity of COPD: 4 (50%) of 8 patients with GOLD1, 13 (72%) of 18 patients with GOLD2, and 2 (100%) of 2 patients with GOLD3. Atrial flutter cycle length and conduction time from the coronary sinus (CS) ostium to the low lateral right atrium (RA) during CS ostium pacing before and after the cavotricuspid isthmus ablation were significantly longer in the COPD group than in the non-COPD group (285 vs. 236, 71 vs. 53, 164 vs. 134 ms; P = 0.009, 0.03, 0.002, respectively). In COPD patients with AF, conduction time of RA was prolonged and typical AFL was commonly observed.

  3. Atrial fibrillation and flutter following coronary artery bypass graft surgery: A retrospective study and review

    Directory of Open Access Journals (Sweden)

    Shyamal Premaratne

    2016-04-01

    Full Text Available Introduction and objectives Atrial fibrillation is a common arrhythmia following coronary artery bypass graft surgery. Its incidence can range from 10 to 60% of patients undergoing coronary artery bypass graft. This rhythm can result in shorter or longer intervals between beats. Methods Medical records of 143 patients from the Queen’s Medical Center, Kuakini Medical Center, Saint Francis Medical Center, and Straub Hospital and Clinic, all of which are located in Honolulu, Hawaii were reviewed. An additional 39 records of patients who did not develop these complications were also reviewed as a control group. Patients were selected according to the ICD codes for atrial fibrillation/flutter and coronary artery bypass graft. Both anomalies can lead to increased health care costs, morbidity, and mortality. In this study, possible predisposing factors to these complications were investigated. The time of onset, weight gain, elapsed time, fluid status (in/out, hematocrit, and drug regimens were compared between the two groups. Results The differences in weight gain, fluid status, and hematocrit between the groups were not significant. There were a total of 17 different drugs prescribed to the group as a whole but not every patient received the same regimen. Conclusions Atrial fibrillation and flutter were found to be more common in males, particularly between the ages of 60 and 69 years. There were no other significant findings.

  4. [Quality of life differences in patients with typical atrial flutter following cavotricuspid isthmus ablation].

    Science.gov (United States)

    García Seara, Javier; Gude, Francisco; Cabanas, Pilar; Martínez Sande, José Luis; Fernández López, Xesús; Elices, Juliana; Brugada Terradellas, Josep; González Juanatey, José Ramón

    2011-05-01

    The aim of the study was to assess and measure health-related quality of life (HRQoL) changes in patients with typical atrial flutter following catheter ablation. The outcome was standardized and normalized to the Spanish population adjusted by age and sex. Ninety-five consecutive patients who had undergone cavotricuspid isthmus ablation were included. The SF-36 questionnaire was self-administered before the procedure and at 1-year follow-up. We used the effect size and the standardized response mean as measures of responsiveness to quantify the change in HRQoL and the minimum clinically important difference to assess the smallest difference in score that patients perceived as beneficial. Of the 95 patients initially included, 88 completed the 1-year follow-up. We observed a large improvement (effect size ≥0.8) on the physical functioning, role-physical , general health, and vitality scales and on the physical component summary. We detected a moderate improvement (effect size ≥0.5) on the role-emotional, social functioning, and mental health scales and on the mental component summary. On all scales except bodily pain and social activity, the improvement was clinically perceived by patients. A clinically significant improvement in HRQoL measures was found in patients with typical atrial flutter who underwent cavotricuspid isthmus catheter ablation. Copyright © 2010 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  5. Dronedarone: an amiodarone analog for the treatment of atrial fibrillation and atrial flutter.

    Science.gov (United States)

    Dale, Krista M; White, C Michael

    2007-04-01

    To review the pharmacology, pharmacokinetics, clinical efficacy, and safety profile of dronedarone for the treatment of atrial fibrillation. A literature search was conducted using the search terms dronedarone, SR 33589, atrial fibrillation, and antiarrhythmic medication in MEDLINE (1966-February 2007), International Pharmaceutical Abstracts (1970-February 2007), and EMBASE (1990-February 2007). References from the identified trials and selected review articles were evaluated. Additional information, including abstracts and posters, was obtained from Sanofi-Aventis. Published studies and meeting abstracts evaluating the effects of dronedarone in humans and animals were reviewed. Dronedarone is a novel antiarrhythmic medication to treat atrial fibrillation. Dronedarone has a multifaceted mechanism of action similar to that of amiodarone. Dronedarone works by blocking potassium, sodium, and calcium channels and exhibits antiadrenergic properties. The drug has been evaluated at doses of 400, 600, and 800 mg twice daily. It prolonged the time to atrial fibrillation recurrence to 60-158 days compared with 5-59 days with placebo and decreased heart rate during atrial fibrillation by 12-25 beats/min in clinical trials. Major adverse events include gastrointestinal side effects and risk of proarrhythmia. Dronedarone may increase the risk of mortality in patients with congestive heart failure. Dronedarone is a new antiarrhythmic agent for the treatment of atrial fibrillation. Further studies are needed to better define dronedarone's safety profile and place in therapy.

  6. Factors affecting the development of atrial fibrillation and atrial flutter (AF/AFL) following autologous hematopoietic SCT (auto-HSCT).

    Science.gov (United States)

    Steuter, J A; Villanueva, M L H; Loberiza, F R; Armitage, J O; Bociek, R G; Ganti, A K; Tarantolo, S R; Vose, J M; Easley, A; Bierman, P J

    2013-07-01

    The use of autologous hematopoietic SCT (auto-HSCT) has expanded to include older patients. Increasing age is a well-appreciated risk factor for the development of atrial fibrillation and/or atrial flutter (AF/AFL) in the general population. As more elderly patients undergo auto-HSCT, the risk of developing AF/AFL post transplant may also increase. However, few data evaluating other risk factors for the development of AF/AFL following auto-HSCT exist. Therefore, we performed a retrospective study to determine the incidence of AF/AFL following auto-HSCT and to determine the risk factors associated with the development of AF/AFL. Patients who developed AF/AFL were compared with a group of patients who received auto-HSCT within the same time period (April 1999 to May 2005) and were within 5 years of age. Of the 516 patients who underwent auto-HSCT at the University of Nebraska Medical Center 44 (8.5%) developed AF/AFL at a median time of 4 days (range, days 1-9) following auto-HSCT. In multivariate analysis, risk factors for developing AF/AFL were older age, odds ratio and 95% CI of 1.14 (1.07-1.21), elevated serum creatinine level, 2.69 (1.00-7.22), history of previous arrhythmia, 9.33 (3.01-28.99), and history of previous mediastinal irradiation, 11.12 (1.33-92.96).

  7. ATRIAL FLUTTER*

    African Journals Online (AJOL)

    1971-01-02

    1923): Arch. Intern. Med., 31, 36. 15. Corday, E. and Irving, D. (1962): Disturbance of Heart Rate, Rhythm and Conduction. Philadelphia: W. B. Saunders. 16. Doliopoulus, T. H. and Marousis, S. (1968): Cardiologia (Basel), 52,.

  8. Oral bisphosphonates and risk of atrial fibrillation and flutter in women: a self-controlled case-series safety analysis.

    Directory of Open Access Journals (Sweden)

    Anthony Grosso

    Full Text Available A recent trial unexpectedly reported that atrial fibrillation, when defined as serious, occurred more often in participants randomized to an annual infusion of the relatively new parenteral bisphosphonate, zoledronic acid, than among those given placebo, but had limited power. Two subsequent population-based case-control studies of patients receiving a more established oral bisphosphonate, alendronic acid, reported conflicting results, possibly due to uncontrolled confounding factors.We used the United Kingdom General Practice Research Database to assess the risk of atrial fibrillation and flutter in women exposed to the oral bisphosphonates, alendronic acid and risedronate sodium. The self-controlled case-series method was used to minimise the potential for confounding. The age-adjusted incidence rate ratio for atrial fibrillation or flutter in individuals during their exposure to these oral bisphosphonates (n = 2195 was 1.07 (95% CI 0.94-1.21. The age-adjusted incidence rate ratio for alendronic acid (n = 1489 and risedronate sodium (n = 649 exposed individuals were 1.09 (95% CI 0.93-1.26 and 0.99 (95% CI 0.78-1.26 respectively. In post-hoc analyses, an increased risk of incident atrial fibrillation or flutter was detected for patients during their first few months of alendronic acid therapy.We found no robust evidence of an overall long-term increased risk of atrial fibrillation or flutter associated with continued exposure to the oral bisphosphonates, alendronic acid and risedronate sodium. A possible signal for an increase in risk during the first few months of therapy with alendronic acid needs to be re-assessed in additional studies.

  9. Emergency Department Management of Atrial Fibrillation and Flutter and Patient Quality of Life at One Month Postvisit.

    Science.gov (United States)

    Ballard, Dustin W; Reed, Mary E; Singh, Nimmie; Rauchwerger, Adina S; Hamity, Courtnee A; Warton, E Margaret; Chettipally, Uli K; Mark, Dustin G; Vinson, David R

    2015-12-01

    We identify characteristics of patients with atrial fibrillation or flutter associated with favorable assessments of emergency department (ED) effectiveness and 30-day quality of life. As part of a prospective observational study of ED management and short-term outcomes of patients with nonvalvular atrial fibrillation or flutter, we adapted a disease-specific quality-of-life instrument. By telephone, we administered the Atrial Fibrillation Effect on Quality-of-life survey to patients 30 days after an ED visit in which they were treated for newly diagnosed or recent-onset atrial fibrillation or flutter and discharged home. We also asked respondents to rate the effectiveness of ED treatment. Using data prospectively collected in the ED and extracted from electronic health records, we recorded rhythm management (cardioversion attempts and type) and patient and ED treatment characteristics. Using multivariable regression, we examined the association between these characteristics and patient-reported effectiveness of ED treatment ("very effective" or not) and any atrial fibrillation or flutter quality-of-life effect. Six hundred fifty-two eligible ED patients (response rate 89%) treated between May 2011 and November 2012 completed follow-up. Of these patients, 454 (69.6%) reported that their ED treatment was "very effective" and 113 (17.3%) reported no quality-of-life influence. In multivariable analyses, there was an association between ED electrocardioversion and perceived ED effectiveness (Pscore. Respondents who were younger, women, and had worse pre-ED self-reported health (Pscore. Copyright © 2015 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

  10. Alta dose de amiodarona em curto período reduz incidência de fibrilação atrial e flutter atrial no pós-operatório de cirurgia de revascularização miocárdica High dose of amiodarone in a short-term period reduces the incidence of postoperative atrial fibrillation and atrial flutter

    Directory of Open Access Journals (Sweden)

    Rafael Vieira Alcalde

    2006-09-01

    Full Text Available OBJETIVOS: Avaliar se a administração de amiodarona, em doses altas e curso rápido, reduz a incidência de fibrilação ou flutter atrial, após cirurgia de revascularização miocárdica e se reduz, também, o tempo de internação hospitalar. MÉTODOS: A amostra se constituiu de 93 pacientes randomizados, em estudo duplo-cego, para receberem amiodarona (46 pacientes ou placebo (47 pacientes. A terapia consistia na aplicação de 600mg de amiodarona, três vezes ao dia, iniciada no mínimo 30 horas e no máximo 56 horas antes da cirurgia. RESULTADOS: Fibrilação ou flutter atrial no pós-operatório ocorreu em 8 dos 46 pacientes no grupo amiodarona (17,4% e em 19 dos 47 pacientes no grupo placebo (40,4% (p=0,027. A dose média de amiodarona foi de 2,8g. Os pacientes do grupo amiodarona ficaram hospitalizados por 8,9±3,1 dias, enquanto a internação dos pacientes do grupo placebo foi de 11,4± 8,7 dias (p=0,07. O tempo de internação foi significativamente prolongado nos pacientes que desenvolveram fibrilação ou flutter atrial após a cirurgia, independente do grupo randomizado. CONCLUSÃO: Esta nova alternativa de administração de amiodarona em alta dose e por um curto período, antes da cirurgia de revascularização miocárdica, reduz a incidência de fibrilação ou flutter atrial no pós-operatório desta cirurgia.OBJECTIVE: To investigate wheter oral amiodarone administered before surgery for a short period in high dose would reduce the incidence of postoperative atrial fibrillation or atrial flutter and reduces the lenght of hospital stay. METHODS: In the double-blind, randomized study, 93 patients were given either oral amiodarone (46 patients or placebo (47 patients. Therapy consisted of 600mg of amiodarone three times a day, started at mininum 30 hours and at maximum 56 hours before surgery. RESULTS: Postoperative atrial fibrillation or atrial flutter occurred in 8 of 46 patients in the amiodarone group (17.4% and 19 of the

  11. The epidemiology and management of recent-onset atrial fibrillation and flutter presenting to the Emergency Department.

    Science.gov (United States)

    Hamilton, Ailsa; Clark, Donna; Gray, Alasdair; Cragg, Aidan; Grubb, Neill

    2015-06-01

    Atrial fibrillation (AF) and flutter are common tachyarrhythmias seen in the Emergency Department (ED). The management of recent-onset AF remains poorly defined. Two management strategies have been proposed: rhythm control versus rate control. The aims of this study were to investigate the epidemiology and management of recent-onset AF presenting to one large tertiary ED. Retrospective analysis of ED records was carried out using the ED PAS database to identify eligible patients presenting between 1 July 2009 and 30 June 2011 with onset of AF in the previous 7 days. Patients were included for analysis if it was their first presentation, first diagnosis or a paroxysm of atrial fibrillation. A total of 494 patients (625 presentations) were analysed. AF (n=564; 90.2%) and flutter (n=61; 9.8%) were the presenting rhythms. In all, 374 (53.8%) presentations were paroxysmal atrial fibrillation. For patients with AF, rhythm control was attempted in 171 (55.0%) patients presenting less than 48 h after symptom onset. Pharmacotherapy was the approach in 105 (31.4%) patients, compared with direct current cardioversion (n=45; 26.3%). Twenty-one patients received both. Flecainide (n=85) and amiodarone (n=33) were the main first-line pharmacotherapies, restoring sinus rhythm in 81.3 and 81.4% of patients, respectively. The overall efficacy of direct current cardioversion in restoring sinus rhythm was similar (78.8%). Eighty-one patients presented more than 48 h after symptom onset. Of those patients managed in the ED (n=38; 71.7%) were managed with rate control. The majority of patients with atrial flutter presented less than 48 h after symptom onset (n=48; 78.7%). Sixteen of these patients were managed with rhythm control strategies in the ED. The epidemiology of recent-onset AF in this series is comparable with previous publications. Rhythm control was only attempted in approximately half of all eligible patients. There was no single-favoured management strategy. Our

  12. Impact of cavotricuspid isthmus morphology in CRYO versus radiofrequency ablation of typical atrial flutter.

    Science.gov (United States)

    Saygi, Serkan; Bastani, Hamid; Drca, Nikola; Insulander, Per; Wredlert, Christer; Schwieler, Jonas; Jensen-Urstad, Mats

    2017-04-01

    Cryoablation (CRYO) is an alternative to radiofrequency (RF) for catheter ablation of cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL). We aimed to study whether different CTI morphologies had different impacts on procedural success for CRYO and RF. This study randomized 153 patients with CTI-dependent AFL (median age 65 years; range 34-82) to RF or CRYO (78 CRYO; 75 RF). Biplane angiography (RAO 30° and LAO 60°) was done before the ablation procedure and isthmuses were classified as straight (n = 81), concave (n = 43) or pouch-like (n = 29). RF was performed with a 3.5-mm open-irrigated tip catheter and CRYO was performed with a 9 F, 8-mm tip catheter. The ablation endpoint was bidirectional block of CTI. Acute procedural success was achieved in 70/75 patients in the RF group and in 72/78 patients in the CRYO group. With regard to CRYO or RF, acute procedural success rates were similar between the three isthmus types: straight: CRYO (92%) and RF (96%); concave: CRYO (92%) and RF (94%); and pouch-like: CRYO (94%) and RF (85%). There were no significant differences regarding success rate between the different morphologies in the CRYO or the RF group. The CTI was longer in patients with acute failure compared to the patients with acute success (38 ± 7 mm versus 33 ± 6 mm, p = 0.045). The CTI morphology did not influence the acute success rate for either the CRYO or the RF ablation of CTI-dependent AFL. A longer CTI was associated with a lower success rate regardless of energy source.

  13. Incidence and prognostic significance of new onset atrial fibrillation/flutter in acute pericarditis.

    Science.gov (United States)

    Imazio, Massimo; Lazaros, George; Picardi, Elisa; Vasileiou, Panagiotis; Orlando, Fabrizio; Carraro, Mara; Tsiachris, Dimitris; Vlachopoulos, Charalambos; Georgiopoulos, George; Tousoulis, Dimitrios; Belli, Riccardo; Gaita, Fiorenzo

    2015-09-01

    Data on the incidence of new onset atrial fibrillation and flutter (AF/f) in patients with acute pericarditis are limited. We sought to determine the incidence and prognostic significance of AF/f in this setting. Between January 2006 and June 2014, consecutive new cases of acute pericarditis were included in two urban referral centres for pericardial diseases. All new cases of AF/f defined as episodes lasting ≥30 s were recorded. Events considered during follow-up consisted of AF/f and pericarditis recurrence, cardiac tamponade, pericardial constriction and death. 822 consecutive new cases of acute pericarditis (mean age 53±15 years, 444 men) were analysed. AF/f was detected in 35 patients (4.3%, mean age 66.5±11.3 years, 18 men). Patients with AF/f were significantly older (p=0.017) and presented more frequently with pericardial effusion (ppericarditis onset in 91.4% of cases, lasted >24 h in 25.7% and spontaneously converted in 74.3% of patients. Underlying structural heart disease was present in 17% of AF/f cases. In a 30-month follow-up, patients with history of AF/f at the initial episode had a higher rate of arrhythmia occurrence (34.3% vs 0.9%, ppericarditis identifies a predisposed population to AF/f with a high recurrence risk (about 35%): in these patients, pericarditis may act as an arrhythmic trigger and oral anticoagulation should be seriously considered according to guidelines. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  14. Catheter selection for ablation of the cavotricuspid isthmus for treatment of typical atrial flutter.

    Science.gov (United States)

    Da Costa, Antoine; Jamon, Yann; Romeyer-Bouchard, Cécile; Thévenin, Jérôme; Messier, Marc; Isaaz, Karl

    2006-11-01

    Radiofrequency catheter ablation (RFA) represents the first line therapy of the cavotricuspid isthmus-dependent atrial flutter (CTI-AFL) with a high efficacy and low secondary effects. RFA of CTI-dependent AFL can be performed by using various types of ablation catheters. Recent evaluations comparing externally cooled tip RFA (ecRFA) catheters and large-tip (8 mm) catheters have revealed that these catheters have a higher efficacy for CTI-AFL ablation compared to 4-mm catheters. The reliability of RFA catheters for AFL is variable and an optimal catheter selection may enhance the RFA effectiveness. The main goal of this article is to review the elements that improve the management of CTI RFA. Preliminary examinations of histopathologic and anatomical elements that may interfere with conventional CTI RFA are presented. Experimental studies concerning the electrobiology of large-tip and cooled-tip catheters are compared. The different catheter designs between cooled-tip and 8-mm-tip catheters are examined (size of the deflectable curve, rotation stability, and size of the distal nonsteerable catheter part) because of their critical role in CTI RFA results. A thorough review of clinical trials of each catheter is presented, and comparison of both catheters in this clinical setting is analyzed. In addition, the role of CTI morphology on AFL RF duration is underlined such as the value of right atrial angiography as an adjunct tool for CTI RFA catheter selection. Based on randomized studies, 8-mm-tip catheters seem to be more effective for ablation in case of straight angiographic isthmus morphology. On the other hand, ecRFA catheters appear to be more effective in cases of complex CTI anatomy or difficult CTI RFA. To reduce X-ray exposition and RFA application time, few studies report that CTI angiographic evaluation before RFA allows a catheter selection based on both CTI morphology and length. Moreover, preliminary data of randomized studies showed that an

  15. Catheter ablation of atrial flutter in patients with left ventricular assist device improves symptoms of right heart failure.

    Science.gov (United States)

    Hottigoudar, Rashmi U; Deam, Allen G; Birks, Emma J; McCants, Kelly C; Slaughter, Mark S; Gopinathannair, Rakesh

    2013-01-01

    Persistent atrial flutter (AFL) in left ventricular assist device (LVAD) recipients can result in loss of AV synchrony, impaired ventricular filling and right heart failure (RHF). The authors report the largest series of HeartMate II (HMII) patients who developed AFL with decompensated RHF, which successfully resolved with AFL ablation. Eight patients with HMII LVAD (mean age, 57±12 years) had medically refractory AFL, with 7 developing de novo AFL after LVAD implant (onset range, 2 days-22 months post-implant). Three patients developed recurrent syncope, 2 had inappropriate implantable cardioverter-defibrillator shocks, and 6 had new or escalating need for inotropes. All had features of decompensated RHF. Seven patients underwent electrophysiology testing where mapping confirmed typical counterclockwise AFL (mean AFL cycle length, 252±49 ms) and radiofrequency ablation of cavotricuspid isthmus restored sinus rhythm in all patients. Complete resolution of symptoms and signs of RHF with improved quality of life were noted in all. No procedural complications were noted. During a mean follow-up of 9±5 months, all patients remained free of atrial flutter. Catheter ablation of AFL in LVAD patients is safe and highly effective, resulting in immediate and significant improvement in symptoms of RHF, and should be considered first-line therapy for AFL in these patients. © 2013 Wiley Periodicals, Inc.

  16. Electrocardiographic and clinical predictors of torsades de pointes induced by almokalant infusion in patients with chronic atrial fibrillation or flutter : A prospective study

    NARCIS (Netherlands)

    Houltz, B; Darpo, B; Edvardsson, N; Blomstrom, P; Brachmann, J; Crijns, Harry J. G. M.; Jensen, Steen M.; Svernhage, E; Vallin, H; Swedberg, K

    The aim of this study was to identify predictors of torsades de pointes (TdP) in patients with atrial fibrillation (AF) or flutter exposed to the Class III antiarrhythmic drug almokalant. TdP can be caused by drugs that prolong myocardial repolarization. One hundred patients received almokalant

  17. Characterization of a stepwise approach in cavotricuspid isthmus ablation for typical atrial flutter: A randomized study comparing three catheters.

    Science.gov (United States)

    Rubín, José Manuel; Calvo, David; Pérez, Diego; Fidalgo, Ana; de la Hera, Jesús María; Martínez, Lidia; Capín, Esmeralda; Arrizabalaga, Haritz; Carballeira, Lidia; García, Daniel; Morís, Cesar

    2017-10-01

    Our aim was to characterize a stepwise approach in cavotricuspid isthmus ablation for typical atrial flutter in a prospective, noncrossover randomized study. One hundred and fifty patients referred for cavotricuspid isthmus (CTI)-dependent atrial flutter ablation were randomized to undergo an ablation with an 8-mm-tip catheter (group 1), a 3.5-mm open irrigation-tip catheter (group 2), and a 3.5-mm open irrigation porous-tip catheter (group 3). A stepwise approach was performed, changing the ablation site from medial to septal aspects of the CTI, in case it was not effective without crossover between catheters. CTI block was achieved in all the patients using only one catheter. There was a 68% efficacy in group 1, 40% in group 2, and 28% in group 3 to achieve CTI block within 10 minutes (P  =  0.001) and 96%, 70%, and 70% in groups 1, 2, and 3, respectively, within 20 minutes (P  =  0.002) of radiofrequency ablation. The 8-mm catheter was also faster in fluoroscopy time and CTI block time. There were no differences in efficiency in the both irrigated catheters. There were no significant differences in complications among three catheters. With this stepwise approach, it is possible to achieve CTI block in all cases, using a single catheter without crossover, with good times of procedure and with a low complication rate. The 8-mm solid catheter is faster than the other irrigated-tip catheters. The 3.5-mm open irrigation porous-tip catheter is as effective and safe as the conventional irrigated-tip catheter. © 2017 Wiley Periodicals, Inc.

  18. Computer-guided normal-low versus normal-high potassium control after cardiac surgery: No impact on atrial fibrillation or atrial flutter.

    Science.gov (United States)

    Hoekstra, Miriam; Hessels, Lara; Rienstra, Michiel; Yeh, Lu; Lansink, Annemieke Oude; Vogelzang, Mathijs; van der Horst, Iwan C C; van der Maaten, Joost M A A; Mariani, Massimo A; de Smet, Anne Marie G A; Struys, Michel M R F; Zijlstra, Felix; Nijsten, Maarten W

    2016-02-01

    This study was designed to determine the effect of 2 different potassium regulation strategies with different targets (within the reference range) on atrial fibrillation (AF) or atrial flutter (AFL) in a cohort of intensive care unit patients after cardiac surgery. The GRIP-COMPASS study was a prospective double-blinded interventional study in 910 patients after cardiac surgery (coronary artery bypass grafting and/or valvular surgery). Patients were assigned to either the normal-low potassium target (nLP group, 4.0 mmol/L) or the normal-high potassium target (nHP group, 4.5 mmol/L) in alternating blocks of 50 patients. Potassium levels were regulated using a validated computer-assisted potassium replacement protocol (GRIP-II). The primary end point was the incidence of AF/AFL on a 12-lead electrocardiogram during the first postoperative week. Of the 910 patients, 447 were assigned to the nLP group; and 463, to the nHP group, with no baseline differences between the 2 groups. The mean daily administered dose of potassium was 30 ± 23 mmol (nLP) versus 52 ± 27 mmol (nHP) (P < .001), which resulted in mean intensive care unit potassium concentration of 4.22 ± 0.36 mmol/L and 4.33 ± 0.34 mmol/L, respectively (P < .001). The incidence of AF/AFL after cardiac surgery did not differ: 38% in the nLP group and 41% in the nHP group. Also in several subgroups (eg, patients not known with prior AF/AFL or with valve surgery), there were no differences. There were no differences in incidence of AF/AFL with 2 potassium regulation strategies with different potassium targets and different amounts of potassium administered in patients after cardiac surgery. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Cost burden of cardiovascular hospitalization and mortality in ATHENA-like patients with atrial fibrillation/atrial flutter in the United States.

    Science.gov (United States)

    Naccarelli, Gerald V; Johnston, Stephen S; Lin, Jay; Patel, Parag P; Schulman, Kathy L

    2010-05-01

    The ATHENA trial (A placebo-controlled, double-blind, parallel arm Trial to assess the efficacy of dronedarone 400 mg bid for the prevention of cardiovascular Hospitalization or death from any cause in patiENts with Atrial fibrillation/atrial flutter) demonstrated that dronedarone reduced the risk of cardiovascular (CV) hospitalization/death by 24% (P or = 70 years with AF/AFL and > or = 1 stroke risk factor, without heart failure) who were hospitalized between January 2, 2005, and January 1, 2007, were identified from the MarketScan databases from Thomson Reuters. Health care costs were evaluated during the 12 months following the index hospitalization. The analysis included 10 200 ATHENA-like patients. Hospitalization for CV causes occurred in 53.9% of patients, with a total of 6700 CV hospitalizations for fatal/nonfatal causes. The most common nonfatal causes of CV hospitalizations were AF/other supraventricular rhythm disorders (20.2% of all CV hospitalizations), congestive heart failure (CHF; 14.3%), and transient ischemic attack (TIA)/stroke (10.7%). Mean costs per CV hospitalization for nonfatal causes were $10,908. Inpatient deaths from CV causes occurred in 264 (2.6%) patients; the most common causes of CV inpatient death were intracranial/gastrointestinal hemorrhage (24.2% of CV deaths), TIA/stroke (17.0%), and CHF (15.9%). Mean hospitalization costs per CV inpatient death were $18,565. Health care costs associated with CV hospitalizations and inpatient deaths among ATHENA-like patients in the US are high. Novel antiarrhythmic therapies such as dronedarone, with the potential to reduce CV hospitalizations/mortality in similar patients, could decrease health care costs if adopted in clinical practice. Copyright 2010 Wiley Periodicals, Inc.

  20. Body Fat, Body Fat Distribution, Lean Body Mass and Atrial Fibrillation and Flutter. A Danish Cohort Study

    Science.gov (United States)

    Frost, Lars; Benjamin, Emelia J.; Fenger-Grøn, Morten; Pedersen, Asger; Tjønneland, Anne; Overvad, Kim

    2014-01-01

    Objective It is recognized that higher height and weight are associated with higher risk of atrial fibrillation or flutter (AF) but it is unclear whether risk of AF is related to body fat, body fat location, or lean body mass. Design and Methods We studied the Danish population-based prospective cohort Diet, Cancer and Health conducted among 55 273 men and women 50-64 years of age at recruitment. We investigated the associations between bioelectrical impedance derived measures of body composition and combinations of anthropometric measures of body fat distribution and risk of an incident record of AF in the Danish Registry of Patients. Results During follow-up (median 13.5 years) AF developed in 1 669 men and 912 women. Higher body fat at any measured location was associated with higher risk of AF. The adjusted hazard ratio (HR) per 1 sex-specific standard deviation (SD) increment in body fat mass was 1.29 (95% confidence interval [CI], 1.24-1.33). Higher lean body mass was also associated with a higher risk of AF. The adjusted HR for 1 sex-specific SD increment was 1.40 (95% CI, 1.35-1.45). Conclusion Higher body fat and higher lean body mass were both associated with higher risk of AF. PMID:24436019

  1. Conduction Velocity around the Tricuspid Valve Annulus during Typical Atrial Flutter by Electro-anatomic Mapping System

    Directory of Open Access Journals (Sweden)

    Akira Sawa, MD

    2006-01-01

    Full Text Available Objective: Conduction velocity around the tricuspid valve annulus (TA. during typical atrial flutter (AFL. has been shown to be slowest in the inferior vena cava-tricuspid valve (IVC-TV. isthmus when compared to the septal or free wall segments of the TA. We investigated the conduction velocity in IVC-TV isthmus, dividing into three areas. Methods: We evaluated conduction velocity around the TA during typical AFL in 10 patients, using an electro-anatomic mapping system (CARTO™. Conduction velocity was calculated at six areas around the TA including the septal wall, upper wall, lateral wall, and isthmus wall, which was further divided into three areas, lateral isthmus, mid isthmus, and septal isthmus. Results: Conduction velocity around the TA during typical AFL was slowest in the IVC-TV isthmus. Further, conduction velocities (m/sec. in the mid isthmus (0.44±0.17. and septal isthmus (0.45±0.22. were significantly slower (p < 0.05. than that in the upper wall (0.67±0.26. Conclusions: The relatively slower conduction in IVC-TV isthmus resulted from the relatively slower conduction in the area from mid to septal isthmus.

  2. Estimation of potential cost savings associated with reduced rates of cardiovascular hospitalization among atrial fibrillation/flutter patients treated with dronedarone in the ATHENA trial.

    Science.gov (United States)

    Reynolds, Matthew R; Lin, Jay; Jhaveri, Mehul; Mozaffari, Essy; Plich, Adam

    2014-01-01

    The aim of this study was to estimate, from a US payer perspective, potential cost savings resulting from the reduction in cardiovascular (CV) hospitalizations obtained with dronedarone in the ATHENA (A Placebo-Controlled, Double-Blind, Parallel Arm Trial to Assess the Efficacy of Dronedarone 400 mg bid for the Prevention of Cardiovascular Hospitalization or Death from any Cause in PatiENts with Atrial Fibrillation/Atrial Flutter) trial. ATHENA randomized atrial fibrillation/flutter patients to dronedarone (n=2301) or placebo (n=2327) plus standard care. Dronedarone significantly reduced first CV hospitalization/all-cause mortality over 12-30 months of follow-up. CV hospitalization costs (2008 values) from a US cohort of ATHENA-like atrial fibrillation/flutter patients with Medicare supplemental insurance (n=10,200) and diagnosis-related group costs of adverse event-related hospitalizations were applied to hospitalizations occurring in ATHENA. The impact of cost variation was assessed using Monte Carlo simulation. In ATHENA, dronedarone reduced the overall CV hospitalization rate (vs. placebo) by 29% over the first 12 months (33.36 vs. 47.19 events per 100 patients) and by 25% over the full study (51.15 vs. 68.55 events per 100 patients). Adverse event-related hospitalization rates (dronedarone vs. placebo) were low (0.48 vs. 0.21 and 0.56 vs. 0.26 events per 100 patients over 12 months and the full study, respectively). Overall hospitalization cost savings were estimated at $1329 and $1763 per patient over 12 months and the full study, respectively. Cost savings were relatively stable [mean (95% confidence interval): $1330 ($994-$1676) for the first 12 months and $1763 ($1369-$2184) for the full study] over 10,000 cycles of random variation.

  3. Prediction of vascular dementia and Alzheimer's disease in patients with atrial fibrillation or atrial flutter using CHADS2 score.

    Science.gov (United States)

    Chou, Ruey-Hsing; Chiu, Chun-Chih; Huang, Chin-Chou; Chan, Wan-Leong; Huang, Po-Hsun; Chen, Yu-Chun; Chen, Tzeng-Ji; Chung, Chia-Min; Lin, Shing-Jong; Chen, Jaw-Wen; Leu, Hsin-Bang

    2016-09-01

    Atrial fibrillation (AF) is associated with an increased risk of dementia. However, limited data are available on the predictors of dementia in patients with AF. This study aimed to evaluate whether the CHADS2 score could be a useful tool for risk stratification with regard to dementia occurrence among patients with AF. AF patients were identified from the National Health Insurance sampling database, which has accumulated a total of 1,000,000 participants since 2000. After excluding patients diagnosed with dementia prior to the index day of enrollment, CHADS2 score was measured to investigate its association with the occurrence of dementia, including vascular dementia and Alzheimer's disease. During the mean follow-up period of 3.71 ± 2.78 years, 1135 dementia cases (7.36%) were identified, including 241 cases of vascular dementia and 894 cases of Alzheimer's disease. In multivariate analysis, an increase of 1 point in the CHADS2 score was independently associated with a 54% increase in the risk of vascular dementia (hazard ratio = 1.54; 95% confidence interval, 1.41-1.69; p vascular dementia as well as Alzheimer's disease in patients with AF. Copyright © 2016. Published by Elsevier Taiwan LLC.

  4. ATRIAL FIBRILLATION OR FLUTTER IN THE EARLY POSTOPERATIVE PERIOD AFTER ASCENDING AORTA AND/OR AORTIC VALVE REPLACEMENT: RISK FACTORS, TREATMENT, PREVENTIVE MAINTENANCE

    Directory of Open Access Journals (Sweden)

    V. V. Ionova

    2010-01-01

    Full Text Available Atrial fibrillation or flutter (AF are frequent complication after replacement of cardiac valves including prosthe- tics of ascending aorta and/or aortic valve, and can cause the infringement of haemodynamics, development of thromboembolic complications, and also increase duration of hospitalisation and treatment cost. The work pur- pose was the attempt to define the most frequent reasons of development AF in early terms after ascending aorta and/or aortic valve replacement, and also medical and preventive tactics at occurrence of these complications. 

  5. Left atrial thrombus resolution in atrial fibrillation or flutter: Results of a prospective study with rivaroxaban (X-TRA) and a retrospective observational registry providing baseline data (CLOT-AF).

    Science.gov (United States)

    Lip, Gregory Y H; Hammerstingl, Christoph; Marin, Francisco; Cappato, Riccardo; Meng, Isabelle Ling; Kirsch, Bodo; van Eickels, Martin; Cohen, Ariel

    2016-08-01

    Data on left atrial/left atrial appendage (LA/LAA) thrombus resolution after non-vitamin K antagonist (VKA) oral anticoagulant treatment are scarce. The primary objective of X-TRA was to explore the use of rivaroxaban for the resolution of LA/LAA thrombi in patients with nonvalvular atrial fibrillation (AF) or atrial flutter, with the CLOT-AF registry providing retrospective data after standard-of-care therapy in this setting. X-TRA was a prospective, single-arm, open-label, multicenter study that investigated rivaroxaban treatment for 6 weeks for LA/LAA thrombus resolution in patients with nonvalvular AF or atrial flutter and LA/LAA thrombus confirmed at baseline on a transesophageal echocardiogram (TEE). CLOT-AF retrospectively collected thrombus-related patient outcome data after standard-of-care anticoagulant treatment for 3 to 12 weeks in patients with nonvalvular AF or atrial flutter who had LA/LAA thrombi on TEE recorded in their medical file. In X-TRA, patients were predominantly (95.0%) from Eastern European countries. The adjudicated thrombus resolution rate was 41.5% (22/53 modified intention-to-treat [mITT] patients, 95% CI 28.1%-55.9%) based on central TEE assessments. Resolved or reduced thrombus was evident in 60.4% (32/53 mITT patients, 95% CI 46.0%-73.6%) of patients. In CLOT-AF, the reported thrombus resolution rate was 62.5% (60/96 mITT patients, 95% CI 52.0%-72.2%) and appeared better in Western European countries (34/50; 68.0%) than in Eastern European countries (26/46; 56.5%). X-TRA is the first prospective, multicenter study examining LA/LAA thrombus resolution with a non-VKA oral anticoagulant in VKA-naïve patients or in patients with suboptimal VKA therapy. Rivaroxaban could be a potential option for the treatment of LA/LAA thrombi. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  6. Maximum voltage gradient technique for optimization of ablation for typical atrial flutter with zero-fluoroscopy approach

    Science.gov (United States)

    Deutsch, Karol; Śledź, Janusz; Mazij, Mariusz; Ludwik, Bartosz; Labus, Michał; Karbarz, Dariusz; Pasicka, Bernadetta; Chrabąszcz, Michał; Śledź, Arkadiusz; Klank-Szafran, Monika; Vitali-Sendoz, Laura; Kameczura, Tomasz; Śpikowski, Jerzy; Stec, Piotr; Ujda, Marek; Stec, Sebastian

    2017-01-01

    Abstract Radiofrequency catheter ablation (RFCA) is an established effective method for the treatment of typical cavo-tricuspid isthmus (CTI)-dependent atrial flutter (AFL). The introduction of 3-dimensional electro-anatomic systems enables RFCA without fluoroscopy (No-X-Ray [NXR]). The aim of this study was to evaluate the feasibility and effectiveness of CTI RFCA during implementation of the NXR approach and the maximum voltage-guided (MVG) technique for ablation of AFL. Data were obtained from prospective standardized multicenter ablation registry. Consecutive patients with the first RFCA for CTI-dependent AFL were recruited. Two navigation approaches (NXR and fluoroscopy based as low as reasonable achievable [ALARA]) and 2 mapping and ablation techniques (MVG and pull-back technique [PBT]) were assessed. NXR + MVG (n  =  164; age: 63.7 ± 9.5; 30% women), NXR + PBT (n  =  55; age: 63.9 ± 10.7; 39% women); ALARA + MVG (n  =  36; age: 64.2 ± 9.6; 39% women); and ALARA + PBT (n  =  205; age: 64.7 ± 9.1; 30% women) were compared, respectively. All groups were simplified with a 2-catheter femoral approach using 8-mm gold tip catheters (Osypka AG, Germany or Biotronik, Germany) with 15 min of observation. The MVG technique was performed using step-by-step application by mapping the largest atrial signals within the CTI. Bidirectional block in CTI was achieved in 99% of all patients (P  =  NS, between groups). In NXR + MVG and NXR + PBT groups, the procedure time decreased (45.4 ± 17.6 and 47.2 ± 15.7 min vs. 52.6 ± 23.7 and 59.8 ± 24.0 min, P < .01) as compared to ALARA + MVG and ALARA + PBT subgroups. In NXR + MVG and NXR + PBT groups, 91% and 98% of the procedures were performed with complete elimination of fluoroscopy. The NXR approach was associated with a significant reduction in fluoroscopy exposure (from 0.2 ± 1.1 [NXR + PBT] and 0.3 ± 1.6 [NXR + MVG] to 7.7 ± 6.0 min [ALARA

  7. Efetividade do metoprolol na prevenção de fibrilação e flutter atrial no pós-operatório de cirurgia de revascularização miocárdica Effectiveness of metoprolol in preventing atrial fibrillation and flutter in the postoperative period of coronary artery bypass graft surgery

    Directory of Open Access Journals (Sweden)

    Eraldo de Azevedo Lúcio

    2004-01-01

    Full Text Available OBJETIVO: Avaliar a efetividade do metoprolol na prevenção de fibrilação e flutter atrial clinicamente detectáveis após cirurgia de revascularização miocárdica. MÉTODOS: Ensaio clínico, randomizado e aberto, para tratar 200 pacientes submetidos à cirurgia de revascularização miocárdica isolada com circulação extracorpórea, randomizados para receber metoprolol, por via oral, ou para não receber a medicação no pós-operatório. Os desfechos de interesse eram a detecção de fibrilação e flutter atrial sustentados, sintomáticos ou que requeressem tratamento. Excluídos do estudo os pacientes com fração de ejeção basal do ventrículo esquerdo 70 anos, as arritmias ocorreram em 2 de 19 pacientes do grupo metoprolol e em 10 de 19 do grupo controle (c2 Yates: p=0,01. O risco relativo foi 0,20 (IC de 95%= 0,05-0,79 e o número necessário para tratar foi de 2 pacientes. CONCLUSÃO: O metoprolol é efetivo na prevenção de fibrilação e flutter atrial no PO de cirurgia de revascularização miocárdica, sendo esse efeito mais marcante no grupo de pacientes idosos.OBJECTIVE: To assess the effectiveness of metoprolol in preventing clinically detectable atrial fibrillation (AF and flutter after coronary artery bypass graft (CABG surgery . METHODS: An open, randomized study was carried out to treat 200 patients who had undergone isolated CABG surgery with extracorporeal circulation. The patients were randomized to either receive metoprolol orally or not to receive the medication in the postoperative period. The outcomes were the detection of sustained atrial AF and flutter, which were symptomatic or required treatment. The patients with the following characteristics were excluded from the study: baseline left ventricular ejection fraction < 35%; previous AF; history of bronchospasm; second- and third-degree atrioventricular blocks, low cardiac output, and heart failure. RESULTS: Arrhythmias occurred in 11 out of 100 patients in

  8. [Comparison of the efficacy and safety of electrical cardioversion and pharmacological cardioversion with nibentan in patients with persisting atrial fibrillation and flutter].

    Science.gov (United States)

    Giliarov, M Iu; Novikova, N A; Sulimov, V A; Suchkova, S A; Syrkin, A L

    2007-01-01

    The aim of the study was to compare the efficacy and safety of pharmacological cardioversion (PC) by nibentan, a class III antiarrhythmic agent, and electrical cardioversion (EC) in patients with persisting atrial fibrillation (AFib) and atrial flutter (AFI) receiving basic antiarrhythmic therapy. Ninety-seven patients with persisting AFib and AFI were included in the trial (45 patients constituted PC group, and 52 constituted EC group). Both groups were comparable according to basic demographic and clinical parameters as well as antiarrhythmic therapy being applied. The results of the study showed that the efficacy of PC did not differ from that of EC (86.7% and 92.3% respectively, p = 0.282). the frequency of arrhythmogenic effect did not differ between the groups either (p = 0.46). One case of non-stable ventricular tachycardia was registered in the PC group. The most significant adverse effect was bradicardia, which was registered more often in the PC group than in EC group (26.7% and 3.8%, respectively, p = 0.001). In conclusion, the efficacy and safety of PC with nibentan in patients with persisting AFib/AFI is comparable with those of EC.

  9. Rationale and design of a study exploring the efficacy of once-daily oral rivaroxaban (X-TRA) on the outcome of left atrial/left atrial appendage thrombus in nonvalvular atrial fibrillation or atrial flutter and a retrospective observational registry providing baseline data (CLOT-AF).

    Science.gov (United States)

    Lip, Gregory Y H; Hammerstingl, Christoph; Marin, Francisco; Cappato, Riccardo; Meng, Isabelle Ling; Kirsch, Bodo; Morandi, Eolo; van Eickels, Martin; Cohen, Ariel

    2015-04-01

    There are still many unresolved issues concerning patient outcomes and prognostic factors in patients with atrial fibrillation (AF) and left atrial/left atrial appendage (LA/LAA) thrombi. Rivaroxaban (Xarelto®), a potent and highly selective oral, direct factor Xa inhibitor, is a new therapeutic option in this setting. The planned study program will consist of a prospective interventional study (X-TRA) and a retrospective observational registry (CLOT-AF). The primary objective of the X-TRA study is to explore the efficacy of rivaroxaban in the treatment of LA/LAA thrombi in patients with nonvalvular AF or atrial flutter, scheduled to undergo cardioversion or AF ablation, in whom an LA/LAA thrombus has been found on transesophageal echocardiography (TEE) before the procedure. The primary end point is the complete LA/LAA thrombus resolution rate at 6 weeks of end of treatment confirmed by TEE. The secondary objectives are to describe categories of thrombus outcome in patients (resolved, reduced, unchanged, larger, or new) confirmed on TEE at the end of treatment (after 6 weeks of treatment), incidence of the composite of stroke and noncentral nervous system systemic embolism at the end of treatment and during follow-up, and incidence of all bleeding at the end of treatment and during follow-up. The objective of the CLOT-AF registry is to provide retrospective thrombus-related patient outcome data after standard-of-care anticoagulant treatment in patients with nonvalvular AF or atrial flutter, who have TEE-documented LA/LAA thrombi. The data will be used as a reference for the prospective X-TRA study. In conclusion, X-TRA and CLOT-AF will provide some answers to the many unresolved issues concerning patient outcomes and prognostic factors in patients with AF and LAA thrombi. Results from this study program would provide the first prospective interventional study (X-TRA) and a large international retrospective observational registry (CLOT-AF) on the prevalence and

  10. Ablação por cateter do flutter atrial. Caracterização eletrofisiológica da interrupção da condução pelos istmos posterior e septal Catheter ablation of atrial flutter. Electrophysiological characterization of posterior and septal isthmus block

    Directory of Open Access Journals (Sweden)

    José Marcos Moreira

    1998-07-01

    Full Text Available OBJETIVO: Avaliar os tipos de bloqueio obtidos nos istmos posterior (entre o anel tricuspídeo e veia cava inferior e septal (entre o anel tricuspídeo e óstio do seio coronário, após ablação do flutter atrial (FLA. MÉTODOS: Foram submetidos à ablação por radiofreqüência (RF 14 pacientes com FLA tipo I (9 homens em 16 procedimentos. A ativação atrial ao redor do anel tricuspídeo foi avaliada em ritmo sinusal utilizando-se cateter "Halo" com 10 pares de eletrodos (H1-2 a H19-20, durante estimulação do seio coronário proximal (SCP e região póstero-lateral do átrio direito (H1-2, antes e após ablações lineares. De acordo com a frente de programação do impulso definiu-se: ausência de bloqueio (condução bidirecional, bloqueio incompleto (condução bidirecional com retardo num dos sentidos e bloqueio completo (ausência de condução pelo istmo. O intervalo desta ativação (deltaSCP/H1-2 foi analisado. RESULTADOS: Bloqueio completo foi obtido em 7 procedimentos (44% e incompleto em 4 (25%. O deltaSCP/H1-2 foi de 74 ± 26ms no primeiro grupo e de 30,5 ± 7,5ms no segundo (pPURPOSE: Evaluate the different types of conduction blocks obtained between inferior vena cava-tricuspid annulus (posterior isthmus and between tricuspid annulus-coronary sinus ostium (septal isthmus after radiofrequency (RF catheter ablation of atrial flutter (AFL METHODS: In 16 procedures, 14 patients (pts, 9 male, with type I AFL underwent RF ablation. Atrial activation around tricuspid annulus was performed with a 10-bipole "Halo" catheter (H1-2; H19-20. In sinus rhythm, isthmus conduction was evaluated during proximal coronary sinus (PCS and low lateral right atrium (H1-2 pacing, before and after linear ablation. According to the wave front of impulse propagation we assessed absence of block (bidirectional conduction; incomplete block (bidirectional conduction with delay in one front of impulse propagation and complete block (absence of conduction

  11. Baseline characteristics and management of patients with atrial fibrillation/flutter in the emergency department: results of a prospective, multicentre registry in China.

    Science.gov (United States)

    Zhang, H; Yang, Y; Zhu, J; Shao, X; Liu, Y; Zhao, L; Yu, P; Zhang, H; He, Q; Gu, X

    2014-08-01

    There have been several studies of atrial fibrillation (AF) over the past decades; however, data from Chinese patients are scarce. The aim of the study was therefore to describe the patient characteristics, risk profile and management strategies for Chinese AF patients presenting to emergency department (ED). We conducted a prospective, multicentre registry of patients with AF or atrial flutter (AFL) in China. Participants were enrolled at 20 EDs, then data regarding baseline characteristics and treatment in EDs were collected. Of the 2016 Chinese patients, 1104 (54.8%) were female. Six hundred eighteen (30.7%) had paroxysmal AF, 452 (22.4%) had persistent AF and 945 (46.9%) had permanent AF. The most common comorbidity was hypertension (55.5%), followed by coronary artery disease (41.8%) and heart failure (HF, 37.4%). The prevalence of concomitant cardiovascular risk factors, such as HF and valvular heart disease, increased as AF progressed. Among the patients with non-valvular AF, 110 (12.7%) of those with CHADS2 (congestive HF, hypertension, age of 75 years and greater, diabetes mellitus and history of stroke) ≥2 were prescribed oral anticoagulants (OAC), while 119 (15.6%) of those with CHADS2 3.0) in 96 patients only (26.4%). Moreover, a total of 16.2% of the patients received ≥1 anti-arrhythmic agents, whereas rate control agents were used more frequently (68.4%). According to the present study, the risk profile and management of Chinese patients with AF/AFL differed from that observed in previous studies. The use of OAC inadequately deviate from current guidelines. © 2014 The Authors; Internal Medicine Journal © 2014 Royal Australasian College of Physicians.

  12. Acute treatment of recent-onset atrial fibrillation and flutter with a tailored dosing regimen of intravenous amiodarone. A randomized, digoxin-controlled study.

    Science.gov (United States)

    Hou, Z Y; Chang, M S; Chen, C Y; Tu, M S; Lin, S L; Chiang, H T; Woosley, R L

    1995-04-01

    A 24 h intravenous dosing regimen of amiodarone was designed to reach a peak plasma concentration at 1 h and to maintain the concentration above a certain level during the infusion period. A randomized, open-label, digoxin-controlled study was undertaken to observe the efficacy and safety of the dosing regimen of amiodarone in treating recent-onset, persistent, atrial fibrillation and flutter with ventricular rates above 130 beats.min-1. Fifty patients with a mean age of 70 +/- 7 (SD) years were enrolled and randomly assigned to receive either amiodarone intravenously (n = 26) or digoxin (n = 24). Amiodarone HCl was infused over 24 h according to the following regimen: 5 mg.min-1, 3 mg.min-1, 1 mg.min-1 and 0.5 mg.min-1 for 1, 3, 6 and 14 h, respectively, for a 70-kg subject. Digoxin (0.013 mg.kg-1) was infused in three divided doses, each dose 2 h apart and infused over 30 min. The mean heart rates in the amiodarone group decreased significantly from 157 +/- 20 beats.min-1 to 122 +/- 25 beats.min-1 after 1 h (P rates, compared to the amiodarone group, in the first 8 h (P amiodarone infusion was prematurely aborted in two patients due to severe bradycardia and death after conversion in one patient and aggravation of heart failure in the other.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Analysis of stroke in ATHENA: a placebo-controlled, double-blind, parallel-arm trial to assess the efficacy of dronedarone 400 mg BID for the prevention of cardiovascular hospitalization or death from any cause in patients with atrial fibrillation/atrial flutter.

    Science.gov (United States)

    Connolly, Stuart J; Crijns, Harry J G M; Torp-Pedersen, Christian; van Eickels, Martin; Gaudin, Christophe; Page, Richard L; Hohnloser, Stefan H

    2009-09-29

    Many patients with atrial fibrillation are at high risk for stroke and require antithrombotic therapy. Antiarrhythmic drugs have not previously been shown to reduce the risk of stroke in atrial fibrillation. The effect of dronedarone, a new multichannel-blocking antiarrhythmic drug, on stroke has been evaluated in a randomized, double-blind clinical trial, ATHENA (A placebo-controlled, double-blind, parallel-arm Trial to assess the efficacy of dronedarone 400 mg BID for the prevention of cardiovascular Hospitalization or death from any cause in patiENts with Atrial fibrillation/atrial flutter). Patients with persistent or paroxysmal atrial fibrillation and at least 1 risk factor for cardiovascular hospitalization were randomized to receive dronedarone (400 mg BID) or double-blind matching placebo and followed up for a minimum of 1 year to a common termination at 30 months. All strokes that occurred during the study were included in the present post hoc analysis. There were 4628 patients randomized to placebo or dronedarone. The baseline risk factors for stroke were well balanced between the 2 groups, and the baseline mean CHADS(2) score was 2. The baseline use of either oral anticoagulant therapy or antiplatelet agent alone was 60%. Dronedarone reduced the risk of stroke from 1.8% per year to 1.2% per year (hazard ratio 0.66, 95% confidence interval 0.46 to 0.96, P=0.027). The effect of dronedarone was similar whether or not patients were receiving oral anticoagulant therapy, and there was a significantly greater effect of dronedarone in patients with higher CHADS(2) scores. In this post hoc analysis, a reduction in stroke was observed in patients with atrial fibrillation who were receiving usual care, which included antithrombotic therapy and heart rate control, who were randomized to dronedarone. Further studies to investigate the effect of dronedarone and other antiarrhythmic agents on stroke are indicated.

  14. Usefulness of vernakalant hydrochloride injection for rapid conversion of atrial fibrillation

    DEFF Research Database (Denmark)

    Pratt, Craig M; Roy, Denis; Torp-Pedersen, Christian

    2010-01-01

    The objective of the present study was to assess the safety and effectiveness of vernakalant hydrochloride injection (RSD1235), a novel antiarrhythmic drug, for the conversion of atrial fibrillation (AF) or atrial flutter to sinus rhythm (SR). Patients with either AF or atrial flutter were...

  15. Atrial Rate And Rhythm Abnormalities In A Patient With Hyperkalemia

    Directory of Open Access Journals (Sweden)

    Jonathan Rosman

    2009-05-01

    Full Text Available A 67 year old man presented with a serum potassium of 7.7 mEq/L and slow atrial flutter with variable A-V block and peaked T waves. Initial treatment for hyperkalemia was followed by an increase in the atrial flutter rate to 300 beats per minute. After hemodialysis the rhythm converted to sinus.

  16. Randomized trial of atrial arrhythmia monitoring to guide anticoagulation in patients with implanted defibrillator and cardiac resynchronization devices

    NARCIS (Netherlands)

    Martin, David T.; Bersohn, Malcolm M.; Waldo, Albert L.; Wathen, Mark S.; Choucair, Wassim K.; Lip, Gregory Y. H.; Ip, John; Holcomb, Richard; Akar, Joseph G.; Halperin, Jonathan L.; Oosterwijk, Jan C.

    2015-01-01

    Aims Atrial tachyarrhythmias (ATs) detected by implanted devices are often atrial fibrillation or flutter (AF) associated with stroke. We hypothesized that introduction and termination of anticoagulation based upon AT monitoring would reduce both stroke and bleeding. Methods and results We

  17. STUDIES ON FLUTTER PREDICTION

    Directory of Open Access Journals (Sweden)

    Irina-Carmen ANDREI

    2012-03-01

    Full Text Available The purpose of this paper is to study the instability of the dynamic flutter. The justification is expressed by the fact that the occurrence of flutter within the aircraft’s flight envelope results in irreversible structural deformation which consequently leads to serious damage. Therefore the mathematical modeling of this phenomenon and its validation are very important. The instability of the dynamic flutter is characterized by critical speed and critical pulsation of oscillatory movements. In this paper, the quasi-stationary model and the Theodorsen model have been analyzed for calculating the aerodynamic forces and torques, and a comparison of them has been carried out. The fluid-structure coupling is done by rewriting the equations, considering that the forces are given by closed formulas. For the mathematical modeling of the flutter there have been used the p-k and V-g methods based on the Theodorsen model and the quasi-stationary model. In order to modeling the free vortices aerodynamic forces and moments, the equations which describe both the motion of the structure and the fluid flow had to be integrated simultaneously in time. The fluid-structure coupling is considered as a combination of two systems that describe the aeroelastic behavior of the structure.

  18. Atrial Ectopics Precipitating Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Johnson Francis

    2015-04-01

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

  19. Randomized, double-blind, placebo-controlled study to evaluate the safety and efficacy of a single oral dose of vanoxerine for the conversion of subjects with recent onset atrial fibrillation or flutter to normal sinus rhythm : RESTORE SR

    NARCIS (Netherlands)

    Piccini, Jonathan P.; Pritchett, Edward L. C.; Davison, Beth A.; Cotter, Gad; Wiener, Laura E.; Koch, Gary; Feld, Gregory; Waldo, Albert; van Gelder, Isabelle C.; Camm, A. John; Kowey, Peter R.; Iwashita, Julie; Dittrich, Howard C.

    BACKGROUND Vanoxerine is an oral, 1,4-dialkylpiperazine derivative antiarrhythmic drug being evaluated for pharmacological cardioversion of atrial fibrillation (AF). OBJECTIVE The purpose of this study was to evaluate the safety and efficacy of vanoxerine for the restoration of sinus rhythm in

  20. The Flutter Shutter Code Calculator

    Directory of Open Access Journals (Sweden)

    Yohann Tendero

    2015-08-01

    Full Text Available The goal of the flutter shutter is to make uniform motion blur invertible, by a"fluttering" shutter that opens and closes on a sequence of well chosen sub-intervals of the exposure time interval. In other words, the photon flux is modulated according to a well chosen sequence calledflutter shutter code. This article provides a numerical method that computes optimal flutter shutter codes in terms of mean square error (MSE. We assume that the observed objects follow a known (or learned random velocity distribution. In this paper, Gaussian and uniform velocity distributions are considered. Snapshots are also optimized taking the velocity distribution into account. For each velocity distribution, the gain of the optimal flutter shutter code with respectto the optimal snapshot in terms of MSE is computed. This symmetric optimization of theflutter shutter and of the snapshot allows to compare on an equal footing both solutions, i.e. camera designs. Optimal flutter shutter codes are demonstrated to improve substantially the MSE compared to classic (patented or not codes. A numerical method that permits to perform a reverse engineering of any existing (patented or not flutter shutter codes is also describedand an implementation is given. In this case we give the underlying velocity distribution fromwhich a given optimal flutter shutter code comes from. The combination of these two numerical methods furnishes a comprehensive study of the optimization of a flutter shutter that includes a forward and a backward numerical solution.

  1. An alternative to the flutter derivatives

    DEFF Research Database (Denmark)

    Andersen, Michael Styrk; Brandt, Anders

    A new simplified framework to study flutter and assess the full scale flutter wind speed is suggested. The flutter instability problem is reduced from a problem involving 8 flutter derivatives to only 4 coefficients. With this method it is possible to estimate the self-excited forces with increased...

  2. Right Atrial Diverticulosis and Early-onset Arrhythmia: Rare Cause of Incessant Neonatal Arrhythmia.

    Science.gov (United States)

    Aggarwal, Neeraj; Joshi, Raja; Joshi, Reena K; Agarwal, Mridul

    2017-06-15

    Atrial flutter not responding to medications could be secondary to structural malformations of heart. A 5-year-old child with resistant arrhythmia, with onset in neonatal period. Multiple right atrial diverticuli were detected on CT angiography and cardiac catheterization. Patient reverted to sinus rhythm following surgical excision of diverticuli. In cases of intractable supraventricular tachycardia, structural anomalies of atrium should be suspected.

  3. Impact of dronedarone on hospitalization burden in patients with atrial fibrillation

    DEFF Research Database (Denmark)

    Torp-Pedersen, Christian; Crijns, Harry J G M; Gaudin, Christophe

    2011-01-01

    Hospitalization or death from any cause in patiENTs with Atrial fibrillation/atrial flutter (ATHENA), a composite of first CV hospitalization or death from any cause, was significantly reduced by dronedarone. This post hoc analysis evaluated the secondary endpoint of CV hospitalization and the clinical benefit...

  4. Usefulness of vernakalant hydrochloride injection for rapid conversion of atrial fibrillation

    DEFF Research Database (Denmark)

    Pratt, Craig M.; Roy, Dennis; Torp-Pedersen, Christian

    2010-01-01

    The objective of the present study was to assess the safety and effectiveness of vernakalant hydrochloride injection (RSD1235), a novel antiarrhythmic drug, for the conversion of atrial fibrillation (AF) or atrial flutter to sinus rhythm (SR). Patients with either AF or atrial flutter were...... infusion of placebo or vernakalant (2 mg/kg) 15 minutes later if the arrhythmia had not terminated. A total of 265 patients were randomized and received treatment. The primary end point was conversion of AF to SR for ≥1 minute within 90 minutes of the start of the drug infusion in the short-duration AF...

  5. Dronedarone for atrial fibrillation: How does it compare with amiodarone?

    Science.gov (United States)

    Penugonda, Neelima; Mohmand-Borkowski, Adam; Burke, James F

    2011-03-01

    Dronedarone (Multaq), an analogue of amiodarone (Cordarone), was designed to cause fewer adverse effects than the parent compound. Studies have indeed shown dronedarone to be safer than amiodarone, but less effective. Its official indication is to reduce the risk of hospitalization in patients with paroxysmal or persistent atrial fibrillation or atrial flutter and other cardiovascular risk factors, reflecting the parameters of its effectiveness in clinical trials.

  6. Analysis of stroke in ATHENA: a placebo-controlled, double-blind, parallel-arm trial to assess the efficacy of dronedarone 400 mg BID for the prevention of cardiovascular hospitalization or death from any cause in patients with atrial fibrillation/atrial flutter

    DEFF Research Database (Denmark)

    Connolly, Stuart J; Crijns, Harry J G M; Torp-Pedersen, Christian

    2009-01-01

    , on stroke has been evaluated in a randomized, double-blind clinical trial, ATHENA (A placebo-controlled, double-blind, parallel-arm Trial to assess the efficacy of dronedarone 400 mg BID for the prevention of cardiovascular Hospitalization or death from any cause in patiENts with Atrial fibrillation...

  7. Real-time flutter analysis

    Science.gov (United States)

    Walker, R.; Gupta, N.

    1984-01-01

    The important algorithm issues necessary to achieve a real time flutter monitoring system; namely, the guidelines for choosing appropriate model forms, reduction of the parameter convergence transient, handling multiple modes, the effect of over parameterization, and estimate accuracy predictions, both online and for experiment design are addressed. An approach for efficiently computing continuous-time flutter parameter Cramer-Rao estimate error bounds were developed. This enables a convincing comparison of theoretical and simulation results, as well as offline studies in preparation for a flight test. Theoretical predictions, simulation and flight test results from the NASA Drones for Aerodynamic and Structural Test (DAST) Program are compared.

  8. Rationale and design of ATHENA: A placebo-controlled, double-blind, parallel arm trial to assess the efficacy of dronedarone 400 mg bid for the prevention of cardiovascular hospitalization or death from any cause in PatiENts with atrial fibrillation/atrial flutter

    DEFF Research Database (Denmark)

    Hohnloser, S.H.; Connolly, S.J.; Crijns, H.J.G.M.

    2008-01-01

    Rationale and Design of ATHENA. Background: Atrial fibrillation (AF) is the most commonly encountered clinical arrhythmia, predominantly affecting elderly patients. There is a continued need for new antiarrhythmic drugs to treat the ever-increasing number of patients with this arrhythmia. Droneda......Rationale and Design of ATHENA. Background: Atrial fibrillation (AF) is the most commonly encountered clinical arrhythmia, predominantly affecting elderly patients. There is a continued need for new antiarrhythmic drugs to treat the ever-increasing number of patients with this arrhythmia....... Dronedarone is a new antiarrhythmic compound currently being developed for treatment of AF. Methods: The ATHENA trial (A placebo-controlled, double-blind, parallel arm Trial to assess the efficacy of dronedarone 400 mg bid for the prevention of cardiovascular Hospitalization or death from any cause in pati...... hospitalization or death from any cause. The study has completed patient enrollment in December 2006 and is expected to end follow-up 1 year later. Conclusion: ATHENA will be the largest efficacy and safety trial of dronedarone, a multichannel blocker compound with properties from class I, II, III, and IV...

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

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, S.; Grimm, R.A. [Cleveland Clinic Foundation, Cleveland, Ohio 44195 (United States); Katz, R. [Naval Undersea Warfare Center, New London, Connecticut 06320 (United States); Thomas, J.D. [Cleveland Clinic Foundation, Cleveland, Ohio 44195 (United States)

    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.

  10. Atrial fibrillation

    African Journals Online (AJOL)

    ABEOLUGBENGAS

    Objective: Atrial fibrillation is the commonest chronic arrhythmia and the etiology is widely varied. The aim of this study was to determine the etiology, clinical characteristics and treatment offered to adult patients with atrial fibrillation managed in a referral hospital in Port Harcourt, southern Nigeria. Methods:A retrospective ...

  11. Validation of post-operative atrial fibrillation in the Western Denmark Heart Registry

    DEFF Research Database (Denmark)

    Munkholm, Sarah Bach; Jakobsen, Carl-Johan; Mortensen, Poul Erik

    2015-01-01

    INTRODUCTION: Post-operative new-onset atrial fibrillation and flutter (POAF) is associated with increased morbidity and mortality following cardiac surgery. Registers and databases are important data sources for observational studies in this research area; hence, the aim was to assess the data...

  12. Electrophysiology of the electrocardiographic changes of atrial fibrillation.

    Science.gov (United States)

    Childers, Rory

    2006-10-01

    The history of atrial fibrillation is described in terms of its electrocardiographic delineation, characteristics and clinical associations. The variant configurations are described and their relationship to rhythm duration and cardioversion success. The inter-relationship of fibrillation with flutter and their diagnostic differences are reviewed. The electrophysiologic basis of atrial remodeling is exemplified, together with its relationship to failure of rate adaptation of the atrial refractory period. Electric countershock causes an acute abbreviation of the atrial refractory period as does the induction of hyperthyroidism in the experimental animal. Current theories of the mechanism of fibrillation and the issue of originating pulmonary venous foci are reviewed. The lack of protection from ventricular fibrillation that exists with preexcitation via an accessory pathway is discussed in terms of the teleological role of orthograde downstream refractory periods.

  13. Subcritical flutter in the acoustics of friction

    National Research Council Canada - National Science Library

    O.N Kirillov

    2008-01-01

    ...-simple eigenfrequencies at the nodes. At contact with friction pads, the rotating continua, such as the singing wine glass or the squealing disc brake, start to vibrate owing to the subcritical flutter instability...

  14. Influence of mistuning on blade torsional flutter

    Science.gov (United States)

    Srinivasan, A. V.

    1980-01-01

    An analytical technique for the prediction of fan blade flutter was evaluated by utilizing first stage fan flutter data from tests on an advanced high performance engine. The formulation includes both aerodynamic and mechanical coupling among all the blades of the assembly. Mistuning is accounted for in the analysis so that individual blade inertias, frequencies, or damping can be considered. Airfoil stability was predicted by calculating a flutter determinant, the eigenvalues of which indicate the extent of susceptibility to flutter. When blade to blade differences in frequencies are considered, a stable system is predicted for the test points examined. For a tuned system, it was found that torsional flutter can be predicted at a limited number of interblade phase angles. Examination of these phase angles indicated that they were "close" to the condition of acoustic resonance. For the range of Mach numbers and reduced frequencies considered, the so called subcritical flutter cannot be predicted. The essential influence of mechanical coupling among the blades is to change the frequencies of the system with little or no change in damping; however, aerodynamic coupling together with mechanical coupling could change not only frequencies, but also damping in the system, with a trend toward instability.

  15. Catheter ablation for paroxysmal atrial fibrillation: segmental pulmonary vein ostial ablation versus left atrial ablation.

    Science.gov (United States)

    Oral, Hakan; Scharf, Christoph; Chugh, Aman; Hall, Burr; Cheung, Peter; Good, Eric; Veerareddy, Srikar; Pelosi, Frank; Morady, Fred

    2003-11-11

    Segmental ostial catheter ablation (SOCA) to isolate the pulmonary veins (PVs) and left atrial catheter ablation (LACA) to encircle the PVs both may eliminate paroxysmal atrial fibrillation (PAF). The relative efficacy of these 2 techniques has not been directly compared. Of 80 consecutive patients with symptomatic PAF (age, 52+/-10 years), 40 patients underwent PV isolation by SOCA and 40 patients underwent LACA to encircle the PVs. During SOCA, ostial PV potentials recorded with a ring catheter were targeted. LACA was performed by encircling the left- and right-sided PVs 1 to 2 cm from the ostia and was guided by an electroanatomic mapping system; ablation lines also were created in the mitral isthmus and posterior left atrium. The mean procedure and fluoroscopy times were 156+/-45 and 50+/-17 minutes for SOCA and 149+/-33 and 39+/-12 minutes for LACA, respectively. At 6 months, 67% of patients who underwent SOCA and 88% of patients who underwent LACA were free of symptomatic PAF when not taking antiarrhythmic drug therapy (P=0.02). Among the variables of age, sex, duration and frequency of PAF, ejection fraction, left atrial size, structural heart disease, and the ablation technique, only an increased left atrial size and the SOCA technique were independent predictors of recurrent PAF. The only complication was left atrial flutter in a patient who underwent LACA. In patients undergoing catheter ablation for PAF, LACA to encircle the PVs is more effective than SOCA.

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

    Science.gov (United States)

    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 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.

  17. Effects of mistuning on blade torsional flutter

    Science.gov (United States)

    Srinivasan, A. V.; Kurkov, A.

    1981-01-01

    An analytical model for the prediction of fan blade flutter is presented and evaluated using data from NASA tests on an advanced high performance engine. For the cascade conditions appropriate to the test points studied, the aerodynamic theory cannot predict subcritical flutter. Under the assumptions of a tuned assembly, the imaginary part of the aerodynamic coefficients does indicate flutter for a limited number of interblade phase angles, but these interblade phase angles are close to those at which the acoustic resonance is predicted. Upon using the individual blade frequencies and solving the mistuned system with aerodynamic coupling only, the results show a stable system. Eigenvectors calculated for the mistuned system demonstrate the presence of several harmonics in each mistuned mode. Inclusion of both mechanical and aerodynamic coupling in the solution of the eigenproblem influences not only the frequencies but also damping in the system with a trend toward stability.

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

    DEFF Research Database (Denmark)

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

    2017-01-01

    by Jakobsen and colleagues. We plan to include all relevant randomised clinical trials assessing the effects of any rhythm control strategy versus any rate control strategy. We plan to search the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS, Science Citation Index Expanded...... and Trial Sequential Analysis. For both our primary and secondary outcomes, we will create a 'Summary of Findings' table and use GRADE assessment to assess the quality of the evidence. DISCUSSION: The results of this systematic review have the potential to benefit thousands of patients worldwide as well...

  19. Digoxin versus placebo, no intervention, or other medical interventions for atrial fibrillation and atrial flutter

    DEFF Research Database (Denmark)

    Sethi, Naqash; Safi, Sanam; Feinberg, Joshua

    2017-01-01

    digoxin with placebo, no intervention, or with other medical interventions. We plan to search the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS, Science Citation Index Expanded on Web of Science, and BIOSIS to identify relevant trials. Any eligible trial...... will be assessed and classified as either at high risk of bias or low risk of bias, and our primary conclusions will be based on trials with low risk of bias. We will perform our meta-analyses of the extracted data using Review Manager 5.3 and Trial Sequential Analysis ver. 0.9.5.5 beta. For both our primary...

  20. Atrial Fibrillation

    Science.gov (United States)

    ... A-Z Clinical Trials Publications and Resources Health Education and Awareness The Science Science Home Blood Disorders ... heart's two upper chambers—called the atria (AY-tree-uh)—to fibrillate. The ... a difficult decision concerning surgery for patients with atrial fibrillation, the ...

  1. Simplified progressive approach for the ablation of scar related atrial macroreentrant tachycardias.

    Science.gov (United States)

    Nava, Santiago; Iturralde-Torres, Pedro; Márquez, Manlio F; Gómez-Flores, Jorge; Cline, Bernardo; Colin-Lizalde, Luis; Victoria, Diana; Hermosillo, Antonio G

    2013-01-01

    Radiofrequency ablation of scar related right atrial flutter is challenging. Long procedures, prolonged fluoroscopic times and high percentages of recurrences are of concern. We present a simple and progressive approach based on a single electroanatomic map of the right atrium. Twenty-two consecutive patients with atrial flutter and history of cardiac surgery were included. An electrophysiologic study was performed to define localization (left or right) and cavo-tricuspid isthmus participation using entrainment mapping. After a critical isthmus was localized, ablation was performed with an external irrigated tip catheter with a power limit of 30 W. Potential ablation sites were confirmed by entrainment. The predominant cardiopathy was atrial septal defect. All arrhythmias were localized in the right atrium; mean cycle length of the clinical flutter was 274 ± 31 ms. Only 40% had cavo-tricuspid isthmus participation. None of the patients with successful ablation had recurrences after 13 ± 9.4 months of follow-up. A progressive approach with only one activation/voltage CARTO(®) map of the atrium and ablation of all potential circuits is a highly effective method for ablating scar related macroreentrant atrial arrhythmias. Copyright © 2012 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

  2. Dronedarone therapy in atrial fibrillation: a summary of recent controlled trials.

    Science.gov (United States)

    Duray, Gabor Z; Schmitt, Jörn; Hohnloser, Stefan H

    2010-12-01

    Dronedarone is a new multichannel blocker, structurally related to amiodarone but free of iodine and less lipophilic and so expected to be free of iodine-related organ toxicity and tissue accumulation. The drug was developed for the treatment of atrial fibrillation (AF). The phase II Dronedarone Atrial FibrillatioN study after Electrical cardioversion (DAFNE) study established 400 mg twice-daily dosing (bid) as the standard dose for dronedarone in the maintenance of sinus rhythm. In the pivotal phase III European Trial In Atrial Fibrillation Or Flutter Patients Receiving Dronedarone For The Maintenance of Sinus Rhythm/ American-Australian-African Trial With Dronedarone In Atrial Fibrillation/flutter Patients For The Maintenance of Sinus Rhythm (EURIDIS/ADONIS) studies in patients with paroxysmal/persistent AF and atrial flutter, dronedarone significantly prolonged the mean time to first AF/flutter recurrence. Although dronedarone proved to be safe in these AF studies, a trial in patients with severe congestive heart failure was prematurely stopped because of excess mortality in the dronedarone relative to the control group. This finding prompted the conduct of a large randomized study in more than 4600 patients with nonpermanent AF, which used the primary end point of time to first cardiovascular (CV) hospitalization or death. Dronedarone significantly reduced the incidence of the primary as well as several secondary end points among which CV mortality was the most significant one. The results of this development program led to the approval of dronedarone for use in patients with AF in several jurisdictions. This article provides a short summary of the most important findings during the clinical development of dronedarone.

  3. 14 CFR 23.629 - Flutter.

    Science.gov (United States)

    2010-01-01

    ... and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... range up to VD; (2) The vibratory response of the structure during the test indicates freedom from... damping as VD is approached. (c) Any rational analysis used to predict freedom from flutter, control...

  4. [Atrial defibrillator].

    Science.gov (United States)

    Jung, W; Lüderitz, B

    2000-01-01

    Atrial fibrillation (AF) is a frequent and costly health care problem representing the most common arrhythmia resulting in hospital admission. Total mortality and cardiovascular mortality are significantly increased in patients with AF compared to controls. In addition to symptoms of palpitations, patients with AF have an increased risk of stroke and may also develop decreased exercise tolerance and left ventricular dysfunction. All of these problems may be reversed with restoration and maintenance of sinus rhythm. External electrical cardioversion has been a remarkably effective and safe method for termination of this arrhythmia. Originally described by Lown et al. in 1963, it has been a well accepted mode of acute therapy. However, this technique requires general anesthesia or heavy sedation. Internal atrial defibrillation has been evaluated as an alternative approach to the external technique for over 2 decades. Recent studies have shown that low-energy internal atrial defibrillation using biphasic shocks is an effective and safe means in restoring sinus rhythm in patients with AF and should be considered especially in patients in whom external cardioversion attempts have failed. Implantable Atrial Defibrillator: Recently, a stand alone IAD, the Metrix System (models 3000 and 3020), has entered clinical investigation. Atrial defibrillation is accomplished by a shock delivered between electrodes in the right atrium and the coronary sinus. The right atrium lead has an active fixation in the right atrium. The coronary sinus lead has a natural spiral configuration for retention in the coronary sinus, and can be straightened with a stylet. Both leads are 7 French in diameter and the defibrillation coils are each 6 cm in length. The electrodes may be placed using separate leads, or very soon by using a single bipolar lead. A separate bipolar right ventricular lead is used for R wave synchronization and post shock pacing. The Metrix defibrillator can be used to induce

  5. Hybrid therapy in the management of atrial fibrillation.

    Science.gov (United States)

    Starek, Zdenk; Lehar, Frantisek; Jez, Jiri; Wolf, Jiri; Novák, Miroslav

    2015-01-01

    Atrial fibrillation is the most common sustained arrhythmia. Because of the sub-optimal outcomes and associated risks of medical therapy as well as the recent advances in non-pharmacologic strategies, a multitude of combined (hybrid) algorithms have been introduced that improve efficacy of standalone therapies while maintaining a high safety profile. Antiarrhythmic administration enhances success rate of electrical cardioversion. Catheter ablation of antiarrhythmic drug-induced typical atrial flutter may prevent recurrent atrial fibrillation. Through simple ablation in the right atrium, suppression of atrial fibrillation may be achieved in patients with previously ineffective antiarrhythmic therapy. Efficacy of complex catheter ablation in the left atrium is improved with antiarrhythmic drugs. Catheter ablation followed by permanent pacemaker implantation is an effective and safe treatment option for selected patients. Additional strategies include pacing therapies such as atrial pacing with permanent pacemakers, preventive pacing algorithms, and/or implantable dual-chamber defibrillators are available. Modern hybrid strategies combining both epicardial and endocardial approaches in order to create a complex set of radiofrequency lesions in the left atrium have demonstrated a high rate of success and warrant further research. Hybrid therapy for atrial fibrillation reviews history of development of non-pharmacological treatment strategies and outlines avenues of ongoing research in this field.

  6. Atrial Arrhythmias in Astronauts - Summary of a NASA Summit

    Science.gov (United States)

    Barr, Yael R.; Watkins, Sharmila D.; Polk, J. D.

    2010-01-01

    Background and Problem Definition: To evaluate NASA s current standards and practices related to atrial arrhythmias in astronauts, Space Medicine s Advanced Projects Section at the Johnson Space Center was tasked with organizing a summit to discuss the approach to atrial arrhythmias in the astronaut cohort. Since 1959, 11 cases of atrial fibrillation, atrial flutter, or supraventricular tachycardia have been recorded among active corps crewmembers. Most of the cases were paroxysmal, although a few were sustained. While most of the affected crewmembers were asymptomatic, those slated for long-duration space flight underwent radiofrequency ablation treatment to prevent further episodes of the arrhythmia. The summit was convened to solicit expert opinion on screening, diagnosis, and treatment options, to identify gaps in knowledge, and to propose relevant research initiatives. Summit Meeting Objectives: The Atrial Arrhythmia Summit brought together a panel of six cardiologists, including nationally and internationally renowned leaders in cardiac electrophysiology, exercise physiology, and space flight cardiovascular physiology. The primary objectives of the summit discussions were to evaluate cases of atrial arrhythmia in the astronaut population, to understand the factors that may predispose an individual to this condition, to understand NASA s current capabilities for screening, diagnosis, and treatment, to discuss the risks associated with treatment of crewmembers assigned to long-duration missions or extravehicular activities, and to discuss recommendations for prevention or management of future cases. Summary of Recommendations: The summit panel s recommendations were grouped into seven categories: Epidemiology, Screening, Standards and Selection, Treatment of Atrial Fibrillation Manifesting Preflight, Atrial Fibrillation during Flight, Prevention of Atrial Fibrillation, and Future Research

  7. Critical phase transitions during ablation of atrial fibrillation

    Science.gov (United States)

    Iravanian, Shahriar; Langberg, Jonathan J.

    2017-09-01

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia with significant morbidity and mortality. Pharmacological agents are not very effective in the management of AF. Therefore, ablation procedures have become the mainstay of AF management. The irregular and seemingly chaotic atrial activity in AF is caused by one or more meandering spiral waves. Previously, we have shown the presence of sudden rhythm organization during ablation of persistent AF. We hypothesize that the observed transitions from a disorganized to an organized rhythm is a critical phase transition. Here, we explore this hypothesis by simulating ablation in an anatomically-correct 3D AF model. In 722 out of 2160 simulated ablation, at least one sudden transition from AF to an organized rhythm (flutter) was noted (33%). They were marked by a sudden decrease in the cycle length entropy and increase in the mean cycle length. At the same time, the number of reentrant wavelets decreased from 2.99 ± 0.06 in AF to 1.76 ± 0.05 during flutter, and the correlation length scale increased from 13.3 ± 1.0 mm to 196.5 ± 86.6 mm (both P < 0.0001). These findings are consistent with the hypothesis that transitions from AF to an anatomical flutter behave as phase transitions in complex non-equilibrium dynamical systems with flutter acting as an absorbing state. Clinically, the facilitation of phase transition should be considered a novel mechanism of ablation and may help to design effective ablation strategies.

  8. Real-time flutter analysis of an active flutter-suppression system on a remotely piloted research aircraft

    Science.gov (United States)

    Gilyard, G. B.; Edwards, J. W.

    1983-01-01

    Flight-test results of the first three flights of an aeroelastic research wing are described. The flight flutter-test technique used to obtain real-time damping estimates from fast-frequency sweep data was obtained and the open-loop flutter boundary determined. Nyquist analyses of sweep maneuvers appear to provide additional valuable information about flutter suppression system operation, both in terms of phase-margin estimates and as a means of evaluating maneuver quality. An error in implementing the flutter-suppression system required in a one-half nominal gain configuration, which caused the wing to be unstable at lower Mach numbers than anticipated, and the vehicle experienced closed-loop flutter on its third flight. Real-time flutter-testing procedures were improved.

  9. Supersonic flutter of panels loaded with inplane shear

    Science.gov (United States)

    Sawyer, J. W.

    1975-01-01

    A modal flutter analysis for biaxially loaded, orthotropic panels, using linear piston-theory aerodynamics, was extended in order to include the effects of inplane shear loading. Flutter boundaries for shear loads up to buckling are calculated for simply supported, isotropic panels of various length-width ratios and for a square, isotropic panel with elastic boundary conditions along the leading and trailing edges. These flutter boundaries are used to define conservative design curves. Sample calculations made using these design curves indicate that practical panels, which have otherwise been adequately designed, could become flutter critical if the inplane shear loads approach the buckling value.

  10. YF-16 flight flutter test procedures

    Science.gov (United States)

    Brignac, W. J.; Ness, H. B.; Johnson, M. K.; Smith, L. M.

    1976-01-01

    The Random Decrement technique (Randomdec) was incorporated in procedures for flight testing of the YF-16 lightweight fighter prototype. Damping values obtained substantiate the adequacy of the flutter margin of safety. To confirm the structural modes which were being excited, a spectral analysis of each channel was performed using the AFFTC time/data 1923/50 time series analyzer. Inflight test procedure included the careful monitoring of strip charts, three axis pulses, rolls, and pullups.

  11. Nonlinear Characteristics of Randomly Excited Transonic Flutter

    DEFF Research Database (Denmark)

    Christiansen, Lasse Engbo; Lehn-Schiøler, Tue; Mosekilde, Erik

    2002-01-01

    shown that the self-sustained oscillations arise in a subcritical Hopf bifurcation. However, analysis of the experimental data also reveals that this bifurcation is modified in various ways. We present an outline of the construction of a 6 DOF model of the aeroelastic behavior of the wing structure...... reproduce several of the experimentally observed modifications of the flutter transition. In particular, the models display the characteristic phenomena of coherence resonance....

  12. Robust Flutter Analysis for Aeroservoelastic Systems

    Science.gov (United States)

    Kotikalpudi, Aditya

    The dynamics of a flexible air vehicle are typically described using an aeroservoelastic model which accounts for interaction between aerodynamics, structural dynamics, rigid body dynamics and control laws. These subsystems can be individually modeled using a theoretical approach and experimental data from various ground tests can be combined into them. For instance, a combination of linear finite element modeling and data from ground vibration tests may be used to obtain a validated structural model. Similarly, an aerodynamic model can be obtained using computational fluid dynamics or simple panel methods and partially updated using limited data from wind tunnel tests. In all cases, the models obtained for these subsystems have a degree of uncertainty owing to inherent assumptions in the theory and errors in experimental data. Suitable uncertain models that account for these uncertainties can be built to study the impact of these modeling errors on the ability to predict dynamic instabilities known as flutter. This thesis addresses the methods used for modeling rigid body dynamics, structural dynamics and unsteady aerodynamics of a blended wing design called the Body Freedom Flutter vehicle. It discusses the procedure used to incorporate data from a wide range of ground based experiments in the form of model uncertainties within these subsystems. Finally, it provides the mathematical tools for carrying out flutter analysis and sensitivity analysis which account for these model uncertainties. These analyses are carried out for both open loop and controller in the loop (closed loop) cases.

  13. Stall Flutter Control of a Smart Blade Section Undergoing Asymmetric Limit Oscillations

    Directory of Open Access Journals (Sweden)

    Nailu Li

    2016-01-01

    Full Text Available Stall flutter is an aeroelastic phenomenon resulting in unwanted oscillatory loads on the blade, such as wind turbine blade, helicopter rotor blade, and other flexible wing blades. Although the stall flutter and related aeroelastic control have been studied theoretically and experimentally, microtab control of asymmetric limit cycle oscillations (LCOs in stall flutter cases has not been generally investigated. This paper presents an aeroservoelastic model to study the microtab control of the blade section undergoing moderate stall flutter and deep stall flutter separately. The effects of different dynamic stall conditions and the consequent asymmetric LCOs for both stall cases are simulated and analyzed. Then, for the design of the stall flutter controller, the potential sensor signal for the stall flutter, the microtab control capability of the stall flutter, and the control algorithm for the stall flutter are studied. The improvement and the superiority of the proposed adaptive stall flutter controller are shown by comparison with a simple stall flutter controller.

  14. Managing atrial fibrillation in the elderly: critical appraisal of dronedarone

    Directory of Open Access Journals (Sweden)

    Trigo P

    2011-12-01

    Full Text Available Paula Trigo, Gregory W FischerDepartment of Anesthesiology, Mount Sinai School of Medicine, New York, NY, USAAbstract: Atrial fibrillation is the most commonly seen arrhythmia in the geriatric population and is associated with increased cardiovascular morbidity and mortality. Treatment of the elderly with atrial fibrillation remains challenging for physicians, because this unique subpopulation is characterized by multiple comorbidities requiring chronic use of numerous medications, which can potentially lead to severe drug interactions. Furthermore, age-related changes in the cardiovascular system as well as other physiological changes result in altered drug pharmacokinetics. Dronedarone is a new drug recently approved for the treatment of arrhythmias, such as atrial fibrillation and/or atrial flutter. Dronedarone is a benzofuran amiodarone analog which lacks the iodine moiety and contains a methane sulfonyl group that decreases its lipophilicity. These differences in chemical structure are responsible for making dronedarone less toxic than amiodarone which, in turn, results in fewer side effects. Adverse events for dronedarone include gastrointestinal side effects and rash. No dosage adjustments are required for patients with renal impairment. However, the use of dronedarone is contraindicated in the presence of severe hepatic dysfunction.Keywords: atrial fibrillation, elderly, antiarrhythmic agents, amiodarone, dronedarone

  15. A three-dimensional human atrial model with fiber orientation. Electrograms and arrhythmic activation patterns relationship.

    Directory of Open Access Journals (Sweden)

    Catalina Tobón

    Full Text Available The most common sustained cardiac arrhythmias in humans are atrial tachyarrhythmias, mainly atrial fibrillation. Areas of complex fractionated atrial electrograms and high dominant frequency have been proposed as critical regions for maintaining atrial fibrillation; however, there is a paucity of data on the relationship between the characteristics of electrograms and the propagation pattern underlying them. In this study, a realistic 3D computer model of the human atria has been developed to investigate this relationship. The model includes a realistic geometry with fiber orientation, anisotropic conductivity and electrophysiological heterogeneity. We simulated different tachyarrhythmic episodes applying both transient and continuous ectopic activity. Electrograms and their dominant frequency and organization index values were calculated over the entire atrial surface. Our simulations show electrograms with simple potentials, with little or no cycle length variations, narrow frequency peaks and high organization index values during stable and regular activity as the observed in atrial flutter, atrial tachycardia (except in areas of conduction block and in areas closer to ectopic activity during focal atrial fibrillation. By contrast, cycle length variations and polymorphic electrograms with single, double and fragmented potentials were observed in areas of irregular and unstable activity during atrial fibrillation episodes. Our results also show: (1 electrograms with potentials without negative deflection related to spiral or curved wavefronts that pass over the recording point and move away, (2 potentials with a much greater proportion of positive deflection than negative in areas of wave collisions, (3 double potentials related with wave fragmentations or blocking lines and (4 fragmented electrograms associated with pivot points. Our model is the first human atrial model with realistic fiber orientation used to investigate the relationship

  16. Implementation of the non-flutter design principle

    DEFF Research Database (Denmark)

    Andersen, Michael Styrk; Sahin, Emrah; Laustsen, Benjamin

    2014-01-01

    The non-flutter design principle is introduced. Aerodynamically stable section model tests performed by three different research groups indicate, that flutter might be avoided if the torsional-to-vertical frequency ratio is kept below 1. A case study of a suspension bridge spanning 3:7 km...

  17. Use of eigenvectors in the solution of the flutter equation

    CSIR Research Space (South Africa)

    Van Zyl, Lourens H

    1993-07-01

    Full Text Available The use of eigenvectors to assign eigenvalues to modes for the p-k formulation of the flutter equation is described. The procedure has the potential to overcome some of the problems of the determinant iteration procedure to solve the flutter...

  18. Non-Flutter Design Principle for long Span Bridges

    DEFF Research Database (Denmark)

    Johansson, Jens; Andersen, Michael Styrk; Starch Øvre, Michele

    The case of flutter on a sharp edged flat plate section model, with a height-to-width ratio of 1:10, has been investigated at four different torsional-to-vertical frequency ratios equal to 0.71, 0.88, 1.19 and 2.10. At a torsional-to-vertical frequency ratio of approximately 1.1 the flutter wind...... velocity for a thin airfoil shows an asymptotical behavior. In traditional bridge design the torsional-to-vertical frequency ratio is increased to obtain higher flutter wind velocities. In the present study, we investigate, what we will label the non-flutter design principle, in which the torsional...... instability. The results are a first indication the non-flutter design principle could be applicable in future design of slender structures....

  19. Interactive flutter analysis and parametric study for conceptual wing design

    Science.gov (United States)

    Mukhopadhyay, Vivek

    1995-01-01

    An interactive computer program was developed for wing flutter analysis in the conceptual design stage. The objective was to estimate the flutter instability boundary of a flexible cantilever wing, when well defined structural and aerodynamic data are not available, and then study the effect of change in Mach number, dynamic pressure, torsional frequency, sweep, mass ratio, aspect ratio, taper ratio, center of gravity, and pitch inertia, to guide the development of the concept. The software was developed on MathCad (trademark) platform for Macintosh, with integrated documentation, graphics, database and symbolic mathematics. The analysis method was based on nondimensional parametric plots of two primary flutter parameters, namely Regier number and Flutter number, with normalization factors based on torsional stiffness, sweep, mass ratio, aspect ratio, center of gravity location and pitch inertia radius of gyration. The plots were compiled in a Vaught Corporation report from a vast database of past experiments and wind tunnel tests. The computer program was utilized for flutter analysis of the outer wing of a Blended Wing Body concept, proposed by McDonnell Douglas Corporation. Using a set of assumed data, preliminary flutter boundary and flutter dynamic pressure variation with altitude, Mach number and torsional stiffness were determined.

  20. Pitx2 prevents susceptibility to atrial arrhythmias by inhibiting left-sided pacemaker specification.

    Science.gov (United States)

    Wang, Jun; Klysik, Elzbieta; Sood, Subeena; Johnson, Randy L; Wehrens, Xander H T; Martin, James F

    2010-05-25

    Atrial fibrillation (AF), the most prevalent sustained cardiac arrhythmia, often coexists with the related arrhythmia atrial flutter (AFL). Limitations in effectiveness and safety of current therapies make an understanding of the molecular mechanism underlying AF more urgent. Genome-wide association studies implicated a region of human chromosome 4q25 in familial AF and AFL, approximately 150 kb distal to the Pitx2 homeobox gene, a developmental left-right asymmetry (LRA) gene. To investigate the significance of the 4q25 variants, we used mouse models to investigate Pitx2 in atrial arrhythmogenesis directly. When challenged by programmed stimulation, Pitx2(null+/-) adult mice had atrial arrhythmias, including AFL and atrial tachycardia, indicating that Pitx2 haploinsufficiency predisposes to atrial arrhythmias. Microarray and in situ studies indicated that Pitx2 suppresses sinoatrial node (SAN)-specific gene expression, including Shox2, in the left atrium of embryos and young adults. In vivo ChIP and transfection experiments indicated that Pitx2 directly bound Shox2 in vivo, supporting the notion that Pitx2 directly inhibits the SAN-specific genetic program in left atrium. Our findings implicate Pitx2 and Pitx2-mediated LRA-signaling pathways in prevention of atrial arrhythmias.

  1. "Cristal tachycardias": origin of right atrial tachycardias from the crista terminalis identified by intracardiac echocardiography.

    Science.gov (United States)

    Kalman, J M; Olgin, J E; Karch, M R; Hamdan, M; Lee, R J; Lesh, M D

    1998-02-01

    We sought to use intracardiac echocardiography (ICE) to identify the anatomic origin of focal right atrial tachycardias and to define their relation with the crista terminalis (CT). Previous studies using ICE during mapping of atrial flutter and inappropriate sinus tachycardia have demonstrated an important relation between endocardial anatomy and electrophysiologic events. Recent studies have suggested that right atrial tachycardias may also have a characteristic anatomic distribution. Twenty-three consecutive patients with 27 right atrial tachycardias were included in the study. ICE was used to facilitate activation mapping in relation to endocardial structures. A 20-pole catheter was positioned along the CT under ICE guidance. ICE was also used to assist in guiding detailed mapping with the ablation catheter in the right atrium. Of 27 focal right atrial tachycardias, 18 (67%, 95% confidence interval [CI] 46% to 83%) were on the CT (2 high medial, 8 high lateral, 6 mid and 2 low). ICE identified the location of the tip of the ablation catheter in immediate relation to the CT in all 18 cases. The 20-pole mapping catheter together with echocardiographic visualization of the CT provided a guide to the site of tachycardia origin along this structure. Radiofrequency ablation was successful in 26 (96%) of 27 (95% CI 81% to 100%) right atrial tachycardias. This study demonstrates that approximately two thirds of focal right atrial tachycardias occurring in the absence of structural heart disease will arise along the CT. Recognition of this common distribution may potentially facilitate mapping and ablation of these tachycardias.

  2. Right bundle branch block with revelation of changing axis deviation at the end of atrial fibrillation.

    Science.gov (United States)

    Patanè, Salvatore; Marte, Filippo; Sturiale, Mauro

    2009-11-12

    Changing axis deviation has been reported also during atrial fibrillation or atrial flutter. Changing axis deviation has been also reported during acute myocardial infarction associated with atrial fibrillation too or at the end of atrial fibrillation during acute myocardial infarction. Left bundle branch block is usually associated with normal or left axis deviation. Rarely the ECG shows a left bundle branch block with changing QRS morphology and changing axis deviation. There are several possible explanations for the intermittent shift in the QRS axis in the presence of complete left bundle branch block. The most plausible explanation is the coexistence of left posterior hemiblock and predivisional left bundle branch block. Intermittent right axis deviation has been rarely reported in the presence of left bundle branch block also during atrial fibrillation and with acute myocardial infarction too. Isolated left posterior hemiblock is a very rare finding and transient right axis deviation associated with a left posterior hemiblock pattern has been also rarely described associated with acute myocardial infarction. Changing axis deviation with changing bundle branch block and new-onset of atrial fibrillation during acute myocardial infarction has been also reported. Changing axis deviation with intermittent right bundle branch block in a patient admitted with acute myocardial infarction has been also described. We present a case of a right bundle branch block with revelation of changing axis deviation at the end of atrial fibrillation in a 68-year-old Italian man.

  3. Relation of porphyria to atrial fibrillation.

    Science.gov (United States)

    Dhoble, Abhijeet; Patel, Mehul B; Abdelmoneim, Sahar S; Puttarajappa, Chethan; Abela, George S; Bhatt, Deepak L; Thakur, Ranjan K

    2009-08-01

    Porphyrias are a group of inherited disorders affecting enzymes in the heme biosynthesis pathway, leading to overproduction and/or accumulation of porphyrin or its precursors. Porphyrias have been associated with autonomic dysfunction, which in turn can develop atrial fibrillation (AF). The purpose of this study was to characterize the prevalence of AF and atrial flutter (AFl) in patients with porphyrias. A single-center retrospective cohort study was designed using data from chart reviews of patients who were admitted to the hospital from January 2000 to June 2008. Fifty-six distinct cases were found with a discharge diagnosis of porphyria including all its subtypes. From the same database, age- and gender-matched controls were identified using computer-generated random numbers. We selected 1 age- and gender-matched control for each case. Electrocardiograms and echocardiograms were reviewed by 2 independent reviewers. Only patients with available 12-lead electrocardiograms that showed AF/AFl were labeled with that diagnosis. All patients with a diagnosis of porphyria were included in the study irrespective of their age. Seven of 56 patients with porphyria met inclusion criteria, yielding a prevalence of AF/AFl of 12.5%. This association was significant (p = 0.028, relative risk 7.45, 95% confidence interval 1.01 to 66.14) compared with the age- and gender-matched control group (2%). In conclusion, our observations suggest that porphyria may be significantly associated with AF/AFl.

  4. A CFD analysis of controlled flutter phenomenon

    Directory of Open Access Journals (Sweden)

    Thirusangu Velmurugan

    2016-01-01

    Full Text Available In the present study, the concept of aero elastic wind energy generator is utilized wind turbines and it applied to produce electricity at low wind speeds. Flutter is the mechanism of dynamic instability in which the energy can be extracted from the wind. This energy might possibly transform into electric power. A straight rectangular wing with single degree of freedom at stalling angle is employed to do suitable work for producing power. A computational model of aero elastic wind energy generator is developed by using ICEM CFD and the flow analysis is carried out at different speeds for the prediction of co-efficient of power for the proposed device. Further a small model is experimentally fabricated and tested in a wind tunnel with different velocities using non-linear theory to predict the power co-efficient of a model. The test results from experiment are compared with the computational results. Thus it is evident that the correlated results are accurate within the acceptable range. The input from the flow analysis is used for structural analysis in ANSYS. The frequency, amplitude of oscillation and phase response of the proposed system can be obtained and it compared with the numerical values from MATLAB simulation of the same system to ensure for obtaining sustained oscillation which is capable of producing power. The flutter mechanism is having the advantage of producing power at very low velocity, eventhough low efficiency.

  5. [Electrophysiological findings and ablation strategies in patients with atrial tachyarrhythmias after left atrial circumferential ablation in the treatment of atrial fibrillation].

    Science.gov (United States)

    Chen, Ming-long; Yang, Bing; Xu, Dong-jie; Zou, Jian-gang; Shan, Qi-jun; Chen, Chun; Chen, Hong-wu; Li, Wen-qi; Cao, Ke-jiang

    2007-02-01

    To report the electrophysiological findings and the ablation strategies in patients with atrial tachyarrhythmias (ATAs) or atrial fibrillation (AF) recurrence after left atrial circumferential ablation (LACA) in the treatment of AF. 91 patients with AF had LACA procedure from April 2004 to May 2006, 19 of which accepted the second ablation procedure due to ATAs or AF recurrence. In all the 19 patients [17 male, 2 female, age 25 - 65 (53 +/- 12) years], 11 presented with paroxysmal AF before the first ablation procedure, 2 with persistent AF and 6 with permanent AF. Pulmonary vein potentials (PVP) were investigated in both sides in all the patients. Delayed PVP was identified inside the left circular line in 5 patients, in the right in 1 and both in 2 during sinus rhythm. "Gap" conduction was found and successfully closed guided by circular mapping catheter. In 3 cases, irregular left atrial tachycardia was caused by fibrillation rhythm inside the left ring via decremental "gap" conduction. Reisolation was done successfully again guided by 3-D mapping and made the left atrium in sinus rhythm but the fibrillation rhythm was still inside the left ring. Pulmonary vein tachycardia with 1:1 conduction to the left atrium presented in one case and reisolation stopped the tachycardia. No PVP was discovered in both sides in 4 patients but other tachycardias could be induced, including two right atrial scar related tachycardias, two supraventricular tachycardias mediated by concealed accessory pathway, one cavo-tricuspid isthmus dependent atrial flutter and one focal atrial tachycardia near the coronary sinus ostium. All the tachycardias in these 4 patients were successfully ablated with the help of routine and 3-D mapping techniques. In the rest 3, which were in AF rhythm, LACA was successfully done again. After a mean follow-up of 4 - 26 (11.5 +/- 8.5) months, 16 patients were symptom free without anti-arrhythmic drug therapy; 1 of them had frequent palpitation attack with

  6. GVT-Based Ground Flutter Test without Wind Tunnel Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc (ZONA) and Arizona State University (ASU) propose a R&D effort to further develop the ground flutter testing system in place of a wind...

  7. Preliminary Evaluation of Nonlinear Effects on TCA Flutter

    Science.gov (United States)

    Arslan, Alan E.; Hartwich, Peter M.; Baker, Myles L.

    1998-01-01

    The objective of this study is to investigate the effect of nonlinear aerodynamics, especially at high angles-of-attack with leading-edge separation, on the TCA flutter properties at transonic speeds. In order to achieve that objective, flutter simulations with Navier-Stokes CFD must be performed. To this end, time-marching Navier-Stokes solutions are computed for the TCA wing/body configuration at high angles-of-attack in transonic flight regimes. The approach is to perform non-linear flutter calculations on the TCA at two angles-of-attack, the first one being a case with attached flow (a=2.8 degrees) and the second one being a high angle-of-attack case with a wing leading edge vortex (a=12.11 degrees). Comparisons of the resulting histories and frequency damping information for both angles-of-attack will evaluate the impact of high-alpha aerodynamics on flutter.

  8. GVT-Based Ground Flutter Test without Wind Tunnel Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc (ZONA) and Arizona State University (ASU) propose a R&D effort to develop a ground flutter testing system without wind tunnel, called the...

  9. Application of a Nonlinear Technique: Flutter Analysis for Turbomachinery Blades

    Science.gov (United States)

    2016-03-30

    rotors[11], flutter analysis in cascades[12] and wind turbine aeroelastics[13]. Another advantage for the high-dimensional harmonic balance method is...rotors and low pressure turbines . The occurrence of flutter could cause high cycle fatigue of blades, shorten engine life time, or in the worst case...engine trends to be increased continually so as to achieve a better efficiency to reduce the fuel consumption. However, it is very challenging for

  10. Deglutition induced atrial tachycardia and atrial fibrillation.

    Science.gov (United States)

    Kanjwal, Yousuf; Imran, Naser; Grubb, Blair

    2007-12-01

    Deglutition induced supraventricular tachycardia is an uncommon condition postulated to be a vagally mediated phenomenon due to mechanical stimulation. Patients usually present with mild symptoms or may have severe debilitating symptoms. Treatment with Class I agents, beta blockers, calcium channel blockers, amiodarone and radiofrquency catheter ablation has shown to be successful in the majority of reported cases. We report the case of a 46-year-old healthy woman presenting with palpitations on swallowing that was documented to be transient atrial tachycardia with aberrant ventricular conduction as well as transient atrial fibrillation. She was successfully treated with propafenone with no induction of swallowing-induced tachycardia after treatment. This is also the first case to show swallowing-induced atrial tachycardia and atrial fibrillation in the same patient.

  11. Piezoelectric Low Net Passive Stiffness (LNPS) flutter test vane

    Science.gov (United States)

    Barnhart, Ryan; Barrett, Ronald M.

    2012-04-01

    This paper outlines the design, fabrication and testing of a new, high performance piezoelectrically driven aircraft flutter test vane. This flutter test vane utilizes low-net passive stiffness (LNPS) actuator configurations to produce deflection amplification ratios on the order of 5:1 while maintaining full blocked moment generation capability. With an order of magnitude lower weight than conventional vanes, the LNPS flight flutter test vane is capable of producing larger amplitude structural deflections with smaller force levels because vane forcing waveforms, frequencies and phasing can be very exactingly controlled with respect to each other. The paper covers the fundamental driving theories behind the device, actuator geometry, test article layout, fabrication and testing. This device was wind tunnel tested at airspeeds up to 110 ft/s with excellent correlation between theory and experiment. Experimental tests show an improvement in angular deflection and delta lift forces from approximately +/-1.8 deg. and 0.45 lbf to +/-8.5 deg. and 1.45 lbf, respectively. The flutter test vane consumes only 1W of peak power at max. actuation frequency, drastically reducing the impact of electrical power supply lines on the modal mass of the wing. This paper describes the modeling, testing and evaluation of the adaptive flutter test vane and quantifies the implications on the current state of flight flutter testing.

  12. Optimized flutter control for an aeroelastic delta wing

    Science.gov (United States)

    Richard, Robert Earl

    The phenomenon of flutter has been a topic of academic research and since the advent of early aircraft. Attempts to suppress it through passive structural design have achieved limited success at the cost of heavier aircraft motivating the development of active control techniques. This work focuses on one such approach referred to as active local damping. The primary focus is to develop an adaptive-structures based method, using computationally efficient modeling tools and transducer optimization techniques, to extend the flutter boundary---the minimum flow speed at which flutter occurs---of an aeroelastic delta wing through active control. System robustness is achieved primarily through the spatial filtering effects of optimized transducers, providing maximized flutter mode targeting with dramatic response reduction in the higher-order system modes. A multi-disciplinary approach is used that incorporates energy based structural modeling, simulation of piezo patch electromechanical coupling, balanced model reduction, vortex lattice aerodynamic modeling, transmission path analysis using Hankel Singular Value (HSV) estimates, and genetic optimization yielding a cohesive and efficient design technique. The control strategy used is based on the assertion that a linear controller built from a linear (pre-flutter) model, if sufficiently robust, can keep the system response linear and continue to function effectively past the point where a passive system would be non-linear. The feasibility of this overall design approach is demonstrated through experimental implementation, yielding a 14% increase in the flutter boundary of the tested model.

  13. On-Line Flutter Prediction Tool for Wind Tunnel Flutter Testing using Parameter Varying Estimation Methodology Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc. (ZONA) proposes to develop an on-line flutter prediction tool for wind tunnel model using the parameter varying estimation (PVE) technique to...

  14. On-Line Flutter Prediction Tool for Wind Tunnel Flutter Testing using Parameter Varying Estimation Methodology Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc. (ZONA) proposes to develop an on-line flutter prediction tool using the parameter varying estimation (PVE) methodology, called the PVE Toolbox,...

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

    Directory of Open Access Journals (Sweden)

    Cátia Costa

    2016-06-01

    Full Text Available 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.

  16. Atrial Fibrillation and Hyperthyroidism

    Directory of Open Access Journals (Sweden)

    Jayaprasad N

    2005-10-01

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

  17. Flutter of cantilevered interconnected beams with variable hinge positions

    Science.gov (United States)

    Deivasigamani, A.; McCarthy, J. M.; John, S.; Watkins, S.; Trivailo, P.; Coman, F.

    2013-04-01

    In this paper, flutter of slender, high-compliance cantilever beams in a fluid flow is discussed. Parametric factors that influence the critical flutter speed of these beams are examined theoretically, and experimentally validated. A relationship between the lowest bending-mode frequency of the beam and its critical flutter speed is established. A single ideal, revolute hinge with zero torsional stiffness is introduced at differing positions along the beam, so as to alter the effective natural frequency of the beam, and the effect of the hinge presence on the first few bending modes is analytically determined. A computational modal analysis is conducted in ANSYS® MechanicalTM and the results match well with analytical results, despite the difference in numerical schemes utilised between the two models. Experiments are then carried out in a smooth-flow wind tunnel to observe the critical flutter speed of these hinged beams. It is found that the critical flutter speed and oscillatory mode shape changes based on the hinge position. The experimental results are compared with the analytical and computational outcomes. Application of these connected bodies in the field of energy harvesting from fluid flow is discussed and the working principle of these harvesters is explained.

  18. [Atrial fibrillation and stroke].

    Science.gov (United States)

    Aamodt, Anne Hege; Sandset, Per Morten; Atar, Dan; Tveit, Arnljot; Russell, David

    2013-08-06

    More than 70,000 Norwegians have atrial fibrillation, which is a major risk factor for ischemic stroke. A large proportion of ischemic strokes caused by atrial fibrillation could be prevented if patients receive optimal prophylactic treatment. This article describes the risk for ischemic stroke in patients with atrial fibrillation, and discusses who should receive prophylactic treatment and which therapy provides the best prevention. The article is based on recently published European, American and Canadian guidelines, a search in PubMed and the authors' own clinical experience. The new risk score CHA2DS2-VASc is better than the CHADS2 score for identifying patients with atrial fibrillation who have a truly low risk of ischemic stroke and are not in need of antithrombotic treatment. Oral anticoagulation therapy is recommended for patients with two or more risk factors for thromboembolism in addition to atrial fibrillation (CHA2DS2-VASc ≥ 2). Patients with atrial fibrillation and a single additional risk factor (CHA2DS2-VASc =1) an individual assessment should be made as to who should receive oral anticoagulants, and for patients with CHA2DS2-VASc = 0 antithrombotic treatment is not recommended. New oral anticoagulants are at least as effective as warfarin for preventing ischemic stroke in patients with nonvalvular atrial fibrillation, they carry a lower risk of cerebral haemorrhage, especially intracranial haemorrhage and are more practical in use. Platelet inhibitors have a minimal role in stroke prevention in patients with atrial fibrillation. Risks stratifying patients using the CHA2DS2-VASc score is a better method for assessing which patients with atrial fibrillation who should receive oral anticoagulation. The introduction of new oral anticoagulants will simplify preventive treatment and hopefully lead to a more efficient anticoagulation treatment in a larger number of patients with atrial fibrillation.

  19. Paroxysmal atrial fibrillation in seven dogs with presumed neurally-mediated syncope.

    Science.gov (United States)

    Porteiro Vázquez, D M; Perego, M; Santos, L; Gerou-Ferriani, M; Martin, M W S; Santilli, R A

    2016-03-01

    To document the electrocardiographic findings of vagally-induced paroxysmal atrial fibrillation following a presumed reflex syncopal episode in the dog. Seven dogs with a syncopal episode followed by a paroxysm of atrial fibrillation recorded on a 24-hour Holter. Twenty-four hour Holter monitors were retrospectively reviewed, analysing the cardiac rhythm associated with syncopal events. Each recording was analysed from 10 min before the syncopal episode to until 10 min after a normal sinus rhythm had returned. Nine episodes were recorded in seven dogs, with one patient experiencing three events during one Holter recording. Five of the seven dogs presented with underlying structural heart disease. In two the syncopal episodes occurred following exercise, two associated with coughing and three were during a period of rest. All dogs had documented on the Holter recording a rhythm abnormality during syncope. The most common finding leading up to the syncopal event was development of a progressive sinus bradycardia, followed by sinus arrest interrupted by a ventricular escape rhythm and then ventricular arrest. This was then followed by an atrial fibrillation. The atrial fibrillation was paroxysmal in seven recordings and persistent in two. In two dogs, the atrial fibrillation reorganised into self-limiting runs of atypical atrial flutter. This combination of electrocardiographic arrhythmias are probably caused by an inappropriate parasympathetic stimulation initiating a reflex or neurally-mediated syncope, with abnormal automaticity of the sinus node and of the subsidiary pacemaker cells and changes in the electrophysiological properties of the atrial muscle, which promoted the paroxysmal atrial fibrillation. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Surface Acoustic Wave Vibration Sensors for Measuring Aircraft Flutter

    Science.gov (United States)

    Wilson, William C.; Moore, Jason P.; Juarez, Peter D.

    2016-01-01

    Under NASA's Advanced Air Vehicles Program the Advanced Air Transport Technology (AATT) Project is investigating flutter effects on aeroelastic wings. To support that work a new method for measuring vibrations due to flutter has been developed. The method employs low power Surface Acoustic Wave (SAW) sensors. To demonstrate the ability of the SAW sensor to detect flutter vibrations the sensors were attached to a Carbon fiber-reinforced polymer (CFRP) composite panel which was vibrated at six frequencies from 1Hz to 50Hz. The SAW data was compared to accelerometer data and was found to resemble sine waves and match each other closely. The SAW module design and results from the tests are presented here.

  1. Beam Flutter and Energy Harvesting in Internal Flow

    Science.gov (United States)

    Tosi, Luis Phillipe; Colonius, Tim; Sherrit, Stewart; Lee, Hyeong Jae

    2017-11-01

    Aeroelastic flutter, largely studied for causing engineering failures, has more recently been used as a means of extracting energy from the flow. Particularly, flutter of a cantilever or an elastically mounted plate in a converging-diverging flow passage has shown promise as an energy harvesting concept for internal flow applications. The instability onset is observed as a function of throat velocity, internal wall geometry, fluid and structure material properties. To enable these devices, our work explores features of the fluid-structure coupled dynamics as a function of relevant nondimensional parameters. The flutter boundary is examined through stability analysis of a reduced order model, and corroborated with numerical simulations at low Reynolds number. Experiments for an energy harvester design are qualitatively compared to results from analytical and numerical work, suggesting a robust limit cycle ensues due to a subcritical Hopf bifurcation. Bosch Corporation.

  2. Tilt-rotor flutter control in cruise flight

    Science.gov (United States)

    Nasu, Ken-Ichi

    1986-01-01

    Tilt-rotor flutter control under cruising operation is analyzed. The rotor model consists of a straight fixed wing, a pylon attached to the wingtip, and a three-blade rotor. The wing is cantilevered to the fuselage and is allowed to bend forward and upward. It also has a torsional degree of freedom about the elastic axis. Each rotor blade has two bending degrees of freedom. Feedback of wingtip velocity and acceleration to cyclic pitch is investigated for flutter control, using strip theory and linearized equations of motion. To determine the feedback gain, an eigenvalue analysis is performed. A second, independent, timewise calculation is conducted to evaluate the control law while employing more sophisticated aerodynamics. The effectiveness of flutter control by cyclic pitch change was confirmed.

  3. Dronedarone: an emerging therapy for atrial fibrillation.

    Science.gov (United States)

    Rosei, Enrico Agabiti; Salvetti, Massimo

    2010-06-01

    Atrial fibrillation (AF) is a common arrhythmia, with a prevalence ranging from 0.1% to 9.0% at different ages, and is associated with increased cardiovascular events and mortality. A significant increase in the prevalence of the disease is expected to occur in the coming years as a consequence of the aging of the population and advances in the management of coronary artery disease and heart failure. Effective rhythm control may be difficult to obtain in a significant proportion of patients with AF. The limited efficacy and the possible adverse effects of antiarrhythmic drugs has led researchers to focus their attention on new molecules, in a search of compounds with antiarrhythmic efficacy and a more favourable safety profile. Among several new drugs developed for the management of AF, dronedarone, a benzofuran derivative that shares many of the antiarrhythmic properties of amiodarone, but with a more favourable safety profile, seems particularly promising. The drug is noniodinated, has less lipophilicity, reaches therapeutic concentrations over a shorter period of time and has lower tissue accumulation. Dronedarone, similarly to amiodarone, exhibits electrophysiologic characteristics of all 4 Vaughan Williams classes. Clinical studies have shown that dronedarone effectively reduces ventricular rate, may prevent or delay the recurrence of AF, and may reduce cardiovascular morbidity and mortality in patients with AF or atrial flutter. The drug has an overall good safety profile, in particular with low pulmonary and thyroid toxicity. An important exception is represented by patients with unstable haemodynamic conditions, in which the use of dronedarone has been found to be associated with an increase in mortality. Dronedarone has been recently approved for clinical use by the Food and Drug Administration and by the European Medicines Agency. Further results from trials and clinical use will better define the efficacy and safety profile of dronedarone in AF compared

  4. Sedimentation and fluttering of a cylinder in a confined liquid

    Science.gov (United States)

    D'Angelo, Maria Veronica; Cachile, Mario; Hulin, Jean-Pierre; Auradou, Harold

    2017-10-01

    The sedimentation and fluttering (angular oscillation of the axis) of straight cylinders are studied in a viscous fluid at rest filling a vertical Hele-Shaw cell for different density contrasts ρs-ρf and fluid viscosities μf and for two cylinder densities ρs and diameters D . The influence of confinement in the cell is studied by comparing the present results to those of the literature for nonconfined fluids. While the confinement and the cylinder length L both influence strongly the mean sedimentation velocity Vs, the characteristics of the fluttering instability are much more similar in the confined and nonconfined cases. While the drag coefficient is nearly constant in a nonconfined fluid, it is larger here and depends both on L (due to flow blockage) and on the Reynolds number ReD=VsD ρf/μf ; the inertial and viscous drag components have equal magnitudes for ReD≃40 . For fluttering, instead, the key parameter is the Froude number Fr=Vs/Vg [Vg=√{(ρs-ρf) g L /ρf }] , and the fluttering oscillations vanish below Fr˜0.07 for all cylinders and fluids investigated. Above this threshold, the angular amplitude increases with Fr up to a plateau value, while that of the horizontal oscillations is, at first, very large and then decreases; both amplitudes are reduced when the viscous drag is dominant, but, if inertial drag is dominant, all data points follow a common trend. For all fluids and cylinders, too, the fluttering frequency varies as f =0.102 Vg/L . These features of fluttering are generally qualitatively similar to those reported in nonconfined fluids, but this instability is observable down to lower ReD values (≃24 instead of ˜200 ).

  5. Mechanical behaviors of Flutter VRP1, Shaker, and Acapella devices.

    Science.gov (United States)

    dos Santos, Alexandre Pereira; Guimarães, Rogério Contato; de Carvalho, Eliane Maria; Gastaldi, Ada Clarice

    2013-02-01

    Flutter VRP1, Shaker, and Acapella are devices that combine positive expiratory pressure (PEP) and oscillations. To compare the mechanical performance of the Flutter VRP1, Shaker, and Acapella devices. An experimental platform and a ventilator, used a flow generator at 5, 10, 15, 20, 26, and 32 L/min, were employed at angles of -30°, 0°, and +30° to evaluate Flutter VRP1 and Shaker, whereas Acapella was adjusted at intermediate, higher, and lower levels of resistance, including positive expiratory pressures (PEP) along with air outflow rates and oscillation frequencies. When the relationships between pressure amplitudes of all air flows were analyzed for the 3 devices at low and intermediate pressures levels, no statistically significant differences were observed in mean pressure amplitudes between Flutter VRP1 and Shaker devices. However, both devices had different values from Acapella, with their pressure amplitude values being higher than that of Acapella (P = .04). There were no statistically significant differences in PEP for the 3 angles or marks regarding all air flows. The expected relationships between variables were observed, with increases in PEP, compared to those of air flows and resistance. Nevertheless, there was a statistically significant difference in frequency of oscillation between these devices and Acapella, whose value was higher than those of Flutter VRP1 and Shaker devices (P = .002). At intermediate pressure levels, the patterns were the same, in comparison to low pressures, although the Acapella device showed frequencies of oscillation values lower than those of Flutter VRP1 and Shaker (P Shaker devices had a similar performance to that of Acapella in many aspects, except for PEP. © 2013 Daedalus Enterprises.

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

    NARCIS (Netherlands)

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

    1997-01-01

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

  7. Large Scale Flutter Data for Design of Rotating Blades Using Navier-Stokes Equations

    Science.gov (United States)

    Guruswamy, Guru P.

    2012-01-01

    A procedure to compute flutter boundaries of rotating blades is presented; a) Navier-Stokes equations. b) Frequency domain method compatible with industry practice. Procedure is initially validated: a) Unsteady loads with flapping wing experiment. b) Flutter boundary with fixed wing experiment. Large scale flutter computation is demonstrated for rotating blade: a) Single job submission script. b) Flutter boundary in 24 hour wall clock time with 100 cores. c) Linearly scalable with number of cores. Tested with 1000 cores that produced data in 25 hrs for 10 flutter boundaries. Further wall-clock speed-up is possible by performing parallel computations within each case.

  8. Fine Particulate air Pollution is Associated with Higher Vulnerability to Atrial Fibrillation—The APACR Study

    OpenAIRE

    Liao, Duanping; Shaffer, Michele L.; He, Fan; Rodriguez-Colon, Sol; Wu, Rongling; Whitsel, Eric A.; Bixler, Edward O.; Cascio, Wayne E.

    2011-01-01

    The acute effects and the time course of fine particulate pollution (PM2.5) on atrial fibrillation/flutter (AF) predictors, including P-wave duration, PR interval duration, and P-wave complexity, were investigated in a community-dwelling sample of 106 nonsmokers. Individual-level 24-h beat-to-beat electrocardiogram (ECG) data were visually examined. After identifying and removing artifacts and arrhythmic beats, the 30-min averages of the AF predictors were calculated. A personal PM2.5 monitor...

  9. Fan Flutter Computations Using the Harmonic Balance Method

    Science.gov (United States)

    Bakhle, Milind A.; Thomas, Jeffrey P.; Reddy, T.S.R.

    2009-01-01

    An experimental forward-swept fan encountered flutter at part-speed conditions during wind tunnel testing. A new propulsion aeroelasticity code, based on a computational fluid dynamics (CFD) approach, was used to model the aeroelastic behavior of this fan. This threedimensional code models the unsteady flowfield due to blade vibrations using a harmonic balance method to solve the Navier-Stokes equations. This paper describes the flutter calculations and compares the results to experimental measurements and previous results from a time-accurate propulsion aeroelasticity code.

  10. Electrocardiografía clínica: Taquiarritmias supraventriculares de origen atrial

    Directory of Open Access Journals (Sweden)

    Abraham Katime Zúñiga

    2013-10-01

    Full Text Available  Resumen Las arritmias se pueden definir como “cualquier anormalidad en la frecuencia, regularidad o sitio de origen del impulso cardiaco o trastorno de la conducción que produce una alteración de la activación auricular o ventricular”; mientras que taquicardia se define como “frecuencia cardiaca en adultos, mayor de 100 latidos por minuto (lat/ min.”. Por tanto, las taquiarritmias supraventriculares son “aquellas taquicardias que requieren tejido atrial o de conducción atrioventricular para su iniciación y mantenimiento”. En este artículo se expondrán las características electrocardiográficas de aquellas provenientes del tejido auricular. (DUAZARY 2010, 117 - 124AbstractThe arrhythmias are defined as “any abnormality in the frequency, regularity, or site of origin of the cardiac impulse or conduction disorder that produces an alteration in the atrial or ventricular activation”; whereas tachycardia is defined as a “heart rate in adults greater than 100 beats per minute”. Therefore, supraventricular tachyarrhythmias are “those tachycardias who require atrial tissue or atrioventricular conduction for its initiation and maintenance”. This article explains the electrocardiographic characteristics of those arrhythmias from atrial tissue.Keywords: Tachyarrhythmia; Tachycardia; Atrial; Auricular; Fibrilation; Flutter; Sinusal; Electrocardiography.

  11. Atrial mass: a myxoma?

    National Research Council Canada - National Science Library

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

    2016-01-01

    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...

  12. Atrial Fibrillation and Stroke

    Science.gov (United States)

    ... faulty heart valves, lung disease, and stimulant or alcohol abuse. Some people will have no identifiable cause for their AF. × Definition Atrial fibrillation (AF) describes the rapid, irregular beating ...

  13. Analysis of tiltrotor whirl flutter in time and frequency domain

    DEFF Research Database (Denmark)

    Kim, Taeseong; Shin, SanJoon; Kim, Taehyoun

    2009-01-01

    flexible wing modes. Numerical results are obtained in both time and frequency domains. Generalized eigenvalue solution is utilized to estimate the whirl flutter stability in the frequency domain, and Runge-Kutta method is used to analyze it in time domain. The effects of varying the pylon spring stiffness...

  14. Determination of Flutter Derivatives for the Great Belt Bridge

    DEFF Research Database (Denmark)

    Poulsen, Niels Kjølstad; Damsgaard, Aage; Reinhold, Thim A.

    1992-01-01

    A new method which combines control theory and system identification techniques has been used to extract flutter derivatives from section model tests for the Great Belt East Bridge. Tests were conducted by exciting the section model simultaneously in vertical and torsional modes of vibration. Tes...... for automating the process of extracting aerodynamic derivatives from recorded time histories of coupled vertical and torsional motion....

  15. Experiences with the design and implementation of flutter suppression systems

    Science.gov (United States)

    Newsom, J. R.; Abel, I.

    1984-01-01

    Research efforts aim at flutter suppression are discussed. The application of active controls technology to reduce the aeroelastic response of aircraft structures is discussed. Feedback control, control law design processes and synthesis, wind tunnel studies, and delta-wing wind tunnel models are discussed.

  16. Kinetic mesh-free method for flutter prediction in turbomachines

    Indian Academy of Sciences (India)

    Carta F O 1967 Coupled Blade-Disc-Shroud flutter Instabilities in Turbo-jet engine Rotors. J. Eng. Power. 89(3): 419–426. Cinnella P, De Palma P, Pascazio G and Napolitano M 2004 A numerical method for turbomachinery aeroelaticity. Trans. ASME 126: 310–316. Deshpande S M 1986 Kinetic theory based new upwind ...

  17. Aeroservoelastic Modeling of Body Freedom Flutter for Control System Design

    Science.gov (United States)

    Ouellette, Jeffrey

    2017-01-01

    The communication of this method is being used by NASA in the ongoing collaborations with groups interested in the X-56A flight test program. Model generation for body freedom flutter Addressing issues in: State Consistency, Low frequency dynamics, Unsteady aerodynamics. Applied approach to X-56A MUTT: Comparing to flight test data.

  18. Flutter-driven triboelectrification for harvesting wind energy.

    Science.gov (United States)

    Bae, Jihyun; Lee, Jeongsu; Kim, SeongMin; Ha, Jaewook; Lee, Byoung-Sun; Park, YoungJun; Choong, Chweelin; Kim, Jin-Baek; Wang, Zhong Lin; Kim, Ho-Young; Park, Jong-Jin; Chung, U-In

    2014-09-23

    Technologies to harvest electrical energy from wind have vast potentials because wind is one of the cleanest and most sustainable energy sources that nature provides. Here we propose a flutter-driven triboelectric generator that uses contact electrification caused by the self-sustained oscillation of flags. We study the coupled interaction between a fluttering flexible flag and a rigid plate. In doing so, we find three distinct contact modes: single, double and chaotic. The flutter-driven triboelectric generator having small dimensions of 7.5 × 5 cm at wind speed of 15 ms(-1) exhibits high-electrical performances: an instantaneous output voltage of 200 V and a current of 60 μA with a high frequency of 158 Hz, giving an average power density of approximately 0.86 mW. The flutter-driven triboelectric generation is a promising technology to drive electric devices in the outdoor environments in a sustainable manner.

  19. Further discrete variable results for a panel flutter optimization problem

    Science.gov (United States)

    Pierson, B. L.; Russell, S. S.

    1973-01-01

    Numerical solutions are presented for the problem of minimum weight design of a thin one-dimensional, simply supported, solid panel in compression, with one side exposed to a parallel high supersonic air flow. The flutter speed is held fixed and a minimum thickness constraint is imposed.

  20. Atrial fibrillation decision support tool: Population perspective.

    Science.gov (United States)

    Eckman, Mark H; Costea, Alexandru; Attari, Mehran; Munjal, Jitender; Wise, Ruth E; Knochelmann, Carol; Flaherty, Matthew L; Baker, Pete; Ireton, Robert; Harnett, Brett M; Leonard, Anthony C; Steen, Dylan; Rose, Adam; Kues, John

    2017-12-01

    Appropriate thromboprophylaxis for patients with atrial fibrillation or atrial flutter (AF) remains a national challenge. The recent availability of direct oral anticoagulants (DOACs) with comparable efficacy and improved safety compared with warfarin alters the balance between risk factors for stroke and benefit of anticoagulation. Our objective was to examine the impact of DOACs as an alternative to warfarin on the net benefit of oral anticoagulant therapy (OAT) in a real-world population of AF patients. This is a retrospective cohort study of patients with paroxysmal or persistent nonvalvular AF. We updated an Atrial Fibrillation Decision Support Tool (AFDST) to include DOACs as treatment options. The tool generates patient-specific recommendations based upon individual patient risk factor profiles for stroke and major bleeding using quality-adjusted life-years (QALYs) calculated for each treatment strategy by a decision analytic model. The setting included inpatient and ambulatory sites in an academic health center in the midwestern United States. The study involved 5,121 adults with nonvalvular AF seen for any ambulatory visit or inpatient hospitalization over the 1-year period (January through December 2016). Outcome measure was net clinical benefit in QALYs. When DOACs are a therapeutic option, the AFDST recommends OAT for 4,134 (81%) patients and no antithrombotic therapy or aspirin for 489 (9%). A strong recommendation for OAT could not be made in 498 (10%) patients. When warfarin is the only option, OAT is recommended for 3,228 (63%) patients and no antithrombotic therapy or aspirin for 973 (19%). A strong recommendation for OAT could not be made in 920 (18%) patients. In total, 1,508 QALYs could be gained if treatment were changed to that recommended by the AFDST. Availability of DOACs increases the proportion of patients for whom oral anticoagulation therapy is recommended in a real-world cohort of AF patients and increased projected QALYs by more than

  1. Ablation for atrial fibrillation: an evidence-based analysis.

    Science.gov (United States)

    2006-01-01

    . For instance, radiofrequency energy uses heat to burn tissue near the source of the arrhythmia. The purpose is to create a series of scar tissue, so that the aberrant electrical pathways can no longer exist. Because the pulmonary veins are the predominant source of AF initiation, the primary goal of ablation is to isolate the pulmonary veins from the left atria through the creation of a conduction block. There are 2 methods of ablation: catheter ablation and surgical (operative) ablation. Radiofrequency energy is most commonly used for ablation. Catheter ablation involves inserting a catheter through the femoral vein to access the heart and burn abnormal foci of electrical activity by direct contact or by isolating them from the rest of the atrium. The surgical ablation is performed minimally invasively via direct visualization or with the assistance of a special scope for patients with lone AF. In March 2006, the following databases were searched: Cochrane Library International Agency for Health Technology Assessment (first quarter 2006), Cochrane Database of Systematic Reviews (first quarter 2006), Cochrane Central Register of Controlled Trials (first quarter 2006), MEDLINE (1966 to February 2006), MEDLINE In-Process and Other Non-indexed Citations (1966 to March 1, 2006), and EMBASE (1980 to 2006 week 9). The Medical Advisory Secretariat also searched Medscape on the Internet for recent reports on trials that were unpublished but that were presented at international conferences. In addition, the Web site Current Controlled Trials (www.controlled-trials.com) was searched for ongoing trials investigating ablation for atrial fibrillation. Search terms included: radiofrequency ablation, catheter ablation and atrial fibrillation. Sixteen RCTs were identified that compared ablation methods in patients with AF. Two studies were identified that investigated first-line therapy for AF or atrial flutter. Seven other studies examined patients with drug-refractory, lone AF; and

  2. Impact of dronedarone on hospitalization burden in patients with atrial fibrillation: results from the ATHENA study.

    Science.gov (United States)

    Torp-Pedersen, Christian; Crijns, Harry J G M; Gaudin, Christophe; Page, Richard L; Connolly, Stuart J; Hohnloser, Stefan H

    2011-08-01

    Cardiovascular (CV) hospitalization is a predictor of CV mortality and has a negative impact on patients' quality of life. The primary endpoint of A placebo-controlled, double-blind, parallel-arm Trial to assess the efficacy of dronedarone 400 mg bid for the prevention of cardiovascular Hospitalization or death from any cause in patiENTs with Atrial fibrillation/atrial flutter (ATHENA), a composite of first CV hospitalization or death from any cause, was significantly reduced by dronedarone. This post hoc analysis evaluated the secondary endpoint of CV hospitalization and the clinical benefit of dronedarone on the number and duration of CV hospitalizations in patients with atrial fibrillation (AF). ATHENA was a double-blind, parallel group study in 4628 patients with a history of paroxysmal/persistent AF and additional risk factors, treated with placebo or dronedarone. Dronedarone treatment significantly reduced the risk of first CV hospitalization (P < 0.0001 vs. placebo), while the risk of first non-CV hospitalization was similar in both groups (P = 0.77). About half of the CV hospitalizations were AF-related, with a median duration of hospital stay of four nights. The risk of any hospitalization for AF [hazard ratio (95% confidence interval) 0.626 (0.546-0.719)] and duration of hospital stay were significantly reduced by dronedarone (P < 0.0001 vs. placebo). Dronedarone treatment reduced total hospitalizations for acute coronary syndrome (P = 0.0105) and the time between the first AF/atrial flutter recurrence and CV hospitalization/death (P = 0.0048). Hospitalization burden was significantly reduced across all levels of care (P < 0.05). Cumulative incidence data indicated that the effects of dronedarone persisted for at least 24 months. Dronedarone reduced the risk for CV hospitalization and the total hospitalization burden in this patient group. The trial is registered under ClinicalTrials.gov #NCT 00174785.

  3. Left atrial appendage occlusion

    Directory of Open Access Journals (Sweden)

    Ahmad Mirdamadi

    2013-01-01

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

  4. A Giant Left Atrial Myxoma

    Directory of Open Access Journals (Sweden)

    Medhat F. Zaher

    2014-01-01

    Full Text Available Atrial myxomas are the most common primary cardiac tumors. Patients with left atrial myxomas generally present with mechanical obstruction of blood flow, systemic embolization, and constitutional symptoms. We present a case of an unusually large left atrial myxoma discovered incidentally in a patient with longstanding dyspnea being managed as bronchial asthma.

  5. Right atrial mural thrombi: An autopsy study of an under-diagnosed complication at an unusual site

    Directory of Open Access Journals (Sweden)

    P Vaideeswar

    2017-01-01

    Full Text Available Background: Right atrial mural thrombi (RAMT are often seen in association with cardiac diseases or foreign bodies. Unusual locations at the flutter isthmus and the atrial appendage prompted us to evaluate our 2-year autopsy data on such thrombi. Materials and Methods: In the 2-year retrospective autopsy, the clinical and autopsy records of patients with RAMT were reviewed, with particular reference to the presence of central venous catheter (CVC, its site of insertion, its type, material and size, its duration of placement, and the drugs infused through the catheter. Results: Of the 940 autopsies performed in 2 years, RAMT was seen in 24 hearts and was related to an insertion of a CVC in 23 patients (95.8%. The risk and/or associated factors for this complication were tunneled and polyethylene catheters, Intensive Care Unit admission, infused drugs, underlying cardiac diseases, and pregnancy. A noteworthy feature was the location of the thrombi in the flutter isthmus in 16 hearts (66.7% and atrial appendage in another six hearts. Localized endocarditis/myocarditis and pulmonary thromboembolism were observed in six and four patients, respectively.Conclusions: This autopsy study, which has a high incidence of catheter-related RAMT, does not reflect the true incidence but reiterates the importance of guided insertion of central venous and prompt recognition of thrombus formation.

  6. Supersonic Flutter Utilization for Effective Energy-Harvesting Based on Piezoelectric Switching Control

    Directory of Open Access Journals (Sweden)

    Kanjuro Makihara

    2012-01-01

    Full Text Available The harvesting of electrical energy generated from the flutter phenomenon of a plate wing is studied using the quasi-steady aerodynamic theory and the finite element method. The example of supersonic flutter structure comes from sounding rockets’ wings. Electrical energy is harvested from supersonic flutter by using piezoelectric patches and switching devices. In order to evaluate the harvesting performance, we simulate flutter dynamics of the plate wing to which piezoelectric patches are attached. We demonstrate that our harvesting system can generate much more electrical energy from wing flutter than conventional harvesting systems can. This flutter utilization changes our perception to a useful one in various fruitful applications from a destructive phenomenon.

  7. Stall Flutter Control of a Smart Blade Section Undergoing Asymmetric Limit Oscillations

    OpenAIRE

    Nailu Li; Balas, Mark J.; Pourya Nikoueeyan; Hua Yang; Naughton, Jonathan W.

    2016-01-01

    Stall flutter is an aeroelastic phenomenon resulting in unwanted oscillatory loads on the blade, such as wind turbine blade, helicopter rotor blade, and other flexible wing blades. Although the stall flutter and related aeroelastic control have been studied theoretically and experimentally, microtab control of asymmetric limit cycle oscillations (LCOs) in stall flutter cases has not been generally investigated. This paper presents an aeroservoelastic model to study the microtab control of the...

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

    NARCIS (Netherlands)

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

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

  9. Application of a flight test and data analysis technique to flutter of a drone aircraft

    Science.gov (United States)

    Bennett, R. M.

    1981-01-01

    Modal identification results presented were obtained from recent flight flutter tests of a drone vehicle with a research wing (DAST ARW-1 for Drones for Aerodynamic and Structural Testing, Aeroelastic Research Wing-1). This vehicle is equipped with an active flutter suppression system (FSS). Frequency and damping of several modes are determined by a time domain modal analysis of the impulse response function obtained by Fourier transformations of data from fast swept sine wave excitation by the FSS control surface on the wing. Flutter points are determined for two different altitudes with the FSS off. Data are given for near the flutter boundary with the FSS on.

  10. Hummingbird feather sounds are produced by aeroelastic flutter, not vortex-induced vibration.

    Science.gov (United States)

    Clark, Christopher J; Elias, Damian O; Prum, Richard O

    2013-09-15

    Males in the 'bee' hummingbird clade produce distinctive, species-specific sounds with fluttering tail feathers during courtship displays. Flutter may be the result of vortex shedding or aeroelastic interactions. We investigated the underlying mechanics of flutter and sound production of a series of different feathers in a wind tunnel. All feathers tested were capable of fluttering at frequencies varying from 0.3 to 10 kHz. At low airspeeds (Uair) feather flutter was highly damped, but at a threshold airspeed (U*) the feathers abruptly entered a limit-cycle vibration and produced sound. Loudness increased with airspeed in most but not all feathers. Reduced frequency of flutter varied by an order of magnitude, and declined with increasing Uair in all feathers. This, along with the presence of strong harmonics, multiple modes of flutter and several other non-linear effects indicates that flutter is not simply a vortex-induced vibration, and that the accompanying sounds are not vortex whistles. Flutter is instead aeroelastic, in which structural (inertial/elastic) properties of the feather interact variably with aerodynamic forces, producing diverse acoustic results.

  11. Pharmacological Treatment for Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Kaoru Sugi, MD PhD

    2005-01-01

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

  12. A MODELING METHOD OF FLUTTERING LEAVES BASED ON POINT CLOUD

    Directory of Open Access Journals (Sweden)

    J. Tang

    2017-09-01

    Full Text Available Leaves falling gently or fluttering are common phenomenon in nature scenes. The authenticity of leaves falling plays an important part in the dynamic modeling of natural scenes. The leaves falling model has a widely applications in the field of animation and virtual reality. We propose a novel modeling method of fluttering leaves based on point cloud in this paper. According to the shape, the weight of leaves and the wind speed, three basic trajectories of leaves falling are defined, which are the rotation falling, the roll falling and the screw roll falling. At the same time, a parallel algorithm based on OpenMP is implemented to satisfy the needs of real-time in practical applications. Experimental results demonstrate that the proposed method is amenable to the incorporation of a variety of desirable effects.

  13. Instrumental variables algorithm for modal parameter identification in flutter testing

    Science.gov (United States)

    Johnson, W.; Gupta, N. K.

    1978-01-01

    The paper is concerned with the task of estimating modal parameters from system response measurement in aircraft flutter testing. A frequency-domain derivation of an instrumental-variables algorithm is presented for a linear time-invariant dynamic system of order n. Basically, this algorithm fits a set of poles and zeros to the measured transfer function. An illustrative example is provided regarding the application of the algorithm to aeroelasticity testing. It is shown that the algorithm can be implemented for on-line data reduction with a microcomputer-based analysis system. By using instrumental variables the sensitivity of the modal parameter estimates to noise in the system-response measurements is reduced greatly. The algorithm is expected to be a powerful and valuable tool for on-line estimation of modal parameters in flutter testing and should be useful in control system and structural dynamics tests.

  14. Aerofoil flutter: fluid-mechanical analysis and wind tunnel testing

    Science.gov (United States)

    Wensuslaus, A. L.; McMillan, A. J.

    2012-08-01

    This paper describes a three dimensional wing model, which has been developed for the purpose of studying flutter, both computationally and through wind tunnel testing. A three dimensional, laminar flow aerofoil wing, based on the NACA aerofoil has been designed. The natural frequencies for this aerofoil were obtained through modal analysis. A scale model wing, without taper was manufactured in the laboratory and tested in a wind tunnel. The pressure data was obtained from fluid flow analysis and the deformation results obtained through structural analysis. The analysis was performed in the ANSYS Workbench Environment, accessing FLUENT CFX for the computational fluid dynamics analysis and the ANSYS FEA package for the mechanical analysis. The computational results obtained are compared with the experimental data obtained in the wind tunnel. Comparison of the analysis and test results provides further understanding of the flutter characteristics.

  15. Active flutter control using discrete optimal constrained dynamic compensators

    Science.gov (United States)

    Broussard, J. R.; Halyo, N.

    1983-01-01

    A method for synthesizing digital active flutter suppression controllers using the concept of optimal output feedback is presented. A recently developd convergent algorithm is employed to determine constrained control law parameters that minimize an infinite-time discrete quadratic performance index. Low-order compensator dynamics are included in the control law and the compensator parameters are computed along with the output feedback gain as part of the optimization process. An input noise adjustment procedure is used to improve the stability margins of the digital active flutter controller. Results from investigations into sample rate variation, prefilter pole variation, and effects of varying flight condtions are discussed. The study indicates that a digital control law which accommodates computation delay can stabilize the wing with reasonable rms performance and adequate stability margins.

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

    Science.gov (United States)

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

    2016-01-01

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

  17. Extension of Flutter Boundaries Using In-Flight Receptance Data

    Science.gov (United States)

    2012-11-01

    in a wind-tunnel aerofoil rig. The aerofoil and its suspension were designed as part of the project. The advantage of the receptance method over...binary flutter in a wind-tunnel aerofoil rig. The aerofoil and its suspension were designed as part of the project. The advantage of the receptance...and determination of control gains. This report describes the theory of the method of receptances and its implementation on a wind- tunnel aerofoil

  18. Holistic approach to flutter clearance using classical methods

    CSIR Research Space (South Africa)

    Van Zyl, Lourens H

    2006-09-01

    Full Text Available extent close spacing of modes will affect the extraction of damping values. PSDs generated by the flight test software for the wing-mounted accelerometers are shown in Fig. 11. The PSDs of the corresponding measured outputs are shown in Fig. 12... values calculated by the flutter flight test software. The results using simulated data indicate that the frequency resolution and processing method could be expected to give accurate results. 3 Conclusions A procedure has been proposed to reduce...

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  20. Rapid voice tremor, or "flutter," in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Aronson, A E; Ramig, L O; Winholtz, W S; Silber, S R

    1992-06-01

    In an attempt to clarify the origin and frequency characteristics of a rapid voice tremor, or "flutter," in patients with amyotrophic lateral sclerosis (ALS), eight patients (four men and four women; ages 42 to 70 years) who had ALS and rapid voice tremor and an age- and sex-matched control group of eight subjects were asked to sustain the vowel /a/ and their voices were recorded for later analysis. Each segment of phonation was demodulated into amplitude and frequency components. From each subject's 8-second amplitude and frequency signals, a fast Fourier transform analysis was done on a 1-second segment previously identified perceptually as having the most apparent tremor or flutter. The results showed that patients with ALS had multiple combinations of levels and frequencies for amplitude and frequency modulations in comparison with control subjects, who had consistently low levels of modulations. In an attempt to quantify the tremor or flutter in ALS, amplitude and frequency modulations were not clearly or predominantly represented at one point along the spectrum. Nevertheless, these frequency and amplitude modulations are more prominent in patients with ALS than in normal subjects. The origins of these aberrant frequency and amplitude modulations in ALS patients remain obscure, although speculation is that they are of peripheral rather than central nervous system origin.

  1. Flutter and divergence instability of supported piezoelectric nanotubes conveying fluid

    Science.gov (United States)

    Bahaadini, Reza; Hosseini, Mohammad; Jamali, Behnam

    2018-01-01

    In this paper, divergence and flutter instabilities of supported piezoelectric nanotubes containing flowing fluid are investigated. To take the size effects into account, the nonlocal elasticity theory is implemented in conjunction with the Euler-Bernoulli beam theory incorporating surface stress effects. The Knudsen number is applied to investigate the slip boundary conditions between the flow and wall of nanotube. The nonlocal governing equations of nanotube are obtained using Newtonian method, including the influence of piezoelectric voltage, surface effects, Knudsen number and nonlocal parameter. Applying Galerkin approach to transform resulting equations into a set of eigenvalue equations under the simple-simple (S-S) and clamped-clamped (C-C) boundary conditions. The effects of the piezoelectric voltage, surface effects, Knudsen number, nonlocal parameter and boundary conditions on the divergence and flutter boundaries of nanotubes are discussed. It is observed that the fluid-conveying nanotubes with both ends supported lose their stability by divergence first and then by flutter with increase in fluid velocity. Results indicate the importance of using piezoelectric voltage, nonlocal parameter and Knudsen number in decrease of critical flow velocities of system. Moreover, the surface effects have a significant role on the eigenfrequencies and critical fluid velocity.

  2. The Relationship between physical activity and risk of atrial fibrillation-A systematic review and meta-Analysis

    DEFF Research Database (Denmark)

    Nielsen, Jens Erik Rokkedal; Wachtell, K; Abdulla, J

    2013-01-01

    The aim of this systematic literature review and meta-Analyses was to explore the relationship between physical activity and risk of new-onset atrial fibrillation (AF) or flutter (AFlu).Results: The search revealed 10 published studies that were eligible for three different meta-Analyses. A meta-......-Analysis of six case-control studies showed that risk of AF increased more than 5-fold in athletes compared to non-Athletic controls, OR=5.3 [(3.6, 7.9; 95% confidence interval (CI)], p...

  3. Effects of flutter and PEP mask physiotherapy on symptoms and lung function in children with cystic fibrosis

    NARCIS (Netherlands)

    C.M. van Winden; A. Visser (Adriaan); P.J. Sterk (Peter); S. Beckers; J.C. de Jongste (Johan); W.C.J. Hop (Wim)

    1998-01-01

    textabstractRecently, the flutter was introduced as a new device to improve sputum expectoration. Preliminary data suggested a significant improvement in expectoration and lung function during flutter treatment in patients with cystic fibrosis (CF). The aim of the

  4. INTRACARDIAC ATRIAL DEFIBRILLATION

    Science.gov (United States)

    Dosdall, Derek J.; Ideker, Raymond E.

    2007-01-01

    Intravascular ventricular defibrillation and intravascular atrial defibrillation have many similarities, some of which are as follows. An important factor influencing the outcome of the shock is the potential gradient field created throughout the ventricles or the atria by the shock. A minimum potential gradient is required throughout the ventricles and probably the atria to defibrillate. The value of this minimum potential gradient is affected by several factors including the duration, tilt, and number of phases of the waveform. For shock strengths near the defibrillation threshold, earliest activation following failed shocks arises in a region in which the potential gradient is low. The defibrillation threshold energy can be decreased by adding a third and even a fourth defibrillation electrode in regions where the shock potential gradient is low for the shock field created by the first two defibrillation electrodes and giving two sequential shocks, each through a different set of electrodes. However, the addition of more electrodes and sequential shocks complicates both the device and its implantation. Since patients are conscious when the atrial defibrillation shock is given, they experience pain during the shock, which is one of the main drawbacks of intravascular atrial defibrillation. Unfortunately, the pain threshold for defibrillation shocks is so low that a shock of less than 1 Joule is uncomfortable and is not much less painful than shocks several times stronger. Therefore, even though electrode configurations exist that have lower atrial defibrillation threshold energy requirements than the atrial defibrillation threshold with standard defibrillation electrode configurations used in implantable cardioverter/defibrillators (ICDs) for ventricular defibrillation, they are not clinically practical because their shocks are almost as painful as with the standard ICD electrode configurations and they would cause the ICD to be more complicated and to take

  5. Unilateral atrial fibrillation - how common is atrial divorce?

    Science.gov (United States)

    Ker, J

    2017-06-01

    Atrial fibrillation is the most common pathologic supraventricular tachycardia. It has many causes, is an expensive disease, impairs quality of life and leads to an increased risk of death. Atrial dissociation is characterised by the presence of two independent sets of P-waves. This peculiar abnormality may give rise to the scenario where one atrium is in atrial fibrillation while the other is in sinus rhythm. This is the first published case of atrial dissociation where the phenomenon is demonstrated by transmitral and transtricuspid pulsed wave Doppler.

  6. HYPERTHYROIDISM AND ATRIAL FIBRILLATION

    Directory of Open Access Journals (Sweden)

    I. M. Marusenko

    2017-01-01

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

  7. Wind Tunnel Measurements for Flutter of a Long-Afterbody Bridge Deck.

    Science.gov (United States)

    Chen, Zeng-Shun; Zhang, Cheng; Wang, Xu; Ma, Cun-Ming

    2017-02-09

    Bridges are an important component of transportation. Flutter is a self-excited, large amplitude vibration, which may lead to collapse of bridges. It must be understood and avoided. This paper takes the Jianghai Channel Bridge, which is a significant part of the Hong Kong-Zhuhai-Macao Bridge, as an example to investigate the flutter of the bridge deck. Firstly, aerodynamic force models for flutter of bridges were introduced. Then, wind tunnel tests of the bridge deck during the construction and the operation stages, under different wind attack angles and wind velocities, were carried out using a high frequency base balance (HFBB) system and laser displacement sensors. From the tests, the static aerodynamic forces and flutter derivatives of the bridge deck were observed. Correspondingly, the critical flutter wind speeds of the bridge deck were determined based on the derivatives, and they are compared with the directly measured flutter speeds. Results show that the observed derivatives are reasonable and applicable. Furthermore, the critical wind speeds in the operation stage is smaller than those in the construction stage. Besides, the flutter instabilities of the bridge in the construction and the operation stages are good. This study helps guarantee the design and the construction of the Jianghai Channel Bridge, and advances the understanding of flutter of long afterbody bridge decks.

  8. Parametric Flutter Analysis of the TCA Configuration and Recommendation for FFM Design and Scaling

    Science.gov (United States)

    Baker, Myles; Lenkey, Peter

    1997-01-01

    The current HSR Aeroelasticity plan to design, build, and test a full span, free flying transonic flutter model in the TDT has many technical obstacles that must be overcome for a successful program. One technical obstacle is the determination of a suitable configuration and point in the sky to use in setting the scaling point for the ASE models program. Determining this configuration and point in the sky requires balancing several conflicting requirements, including model buildability, tunnel test safety, and the ability of the model to represent the flutter mechanisms of interest. As will be discussed in detail in subsequent sections, the current TCA design exhibits several flutter mechanisms of interest. It has been decided that the ASE models program will focus on the low frequency symmetric flutter mechanism, and will make no attempt to investigate high frequency flutter mechanisms. There are several reasons for this choice. First, it is believed that the high frequency flutter mechanisms are similar in nature to classical wing bending/torsion flutter, and therefore there is more confidence that this mechanism can be predicted using current techniques. The low frequency mode, on the other hand, is a highly coupled mechanism involving wing, body, tail, and engine motion which may be very difficult to predict. Second, the high frequency flutter modes result in very small weight penalties (several hundred pounds), while suppression of the low frequency mechanism inside the flight envelope causes thousands of pounds to be added to the structure. In order to successfully test the low frequency flutter mode of interest, a suitable starting configuration and point in the sky must be identified. The configuration and point in the sky must result in a wind tunnel model that (1) represents the low-frequency wing/body/engine/empennage flutter mechanisms that are unique to HSCT configurations, (2) flutters at an acceptably low frequency in the tunnel, (3) flutters at an

  9. Rhythm- and Rate-Controlling Effects of Dronedarone in Patients With Atrial Fibrillation (from the ATHENA Trial)

    DEFF Research Database (Denmark)

    Page, Richard L; Connolly, Stuart J; Crijns, Harry J G M

    2011-01-01

    .i.d. for the Prevention of Cardiovascular Hospitalization or Death from Any Cause in Patients With Atrial Fibrillation/Atrial Flutter (ATHENA) demonstrated that dronedarone reduced the risk for first cardiovascular hospitalization or death from any cause. The aim of this post hoc analysis was to evaluate the rhythm......- and rate-controlling properties of dronedarone in the ATHENA trial. Patients were randomized to dronedarone 400 mg twice daily (n 2,301) or placebo (n 2,327). Electrocardiographic tracings were classified for AF or AFL or sinus rhythm. Patients with AF or AFL on every postbaseline electrocardiogram were......, dronedarone demonstrated both rhythm- and rate-controlling properties in ATHENA. These effects are likely to contribute to the reduction of important clinical outcomes observed in this trial....

  10. Developing Uncertainty Models for Robust Flutter Analysis Using Ground Vibration Test Data

    Science.gov (United States)

    Potter, Starr; Lind, Rick; Kehoe, Michael W. (Technical Monitor)

    2001-01-01

    A ground vibration test can be used to obtain information about structural dynamics that is important for flutter analysis. Traditionally, this information#such as natural frequencies of modes#is used to update analytical models used to predict flutter speeds. The ground vibration test can also be used to obtain uncertainty models, such as natural frequencies and their associated variations, that can update analytical models for the purpose of predicting robust flutter speeds. Analyzing test data using the -norm, rather than the traditional 2-norm, is shown to lead to a minimum-size uncertainty description and, consequently, a least-conservative robust flutter speed. This approach is demonstrated using ground vibration test data for the Aerostructures Test Wing. Different norms are used to formulate uncertainty models and their associated robust flutter speeds to evaluate which norm is least conservative.

  11. Concomitant atrial fibrillation surgery for people undergoing cardiac surgery

    Science.gov (United States)

    Huffman, Mark D; Karmali, Kunal N; Berendsen, Mark A; Andrei, Adin-Cristian; Kruse, Jane; McCarthy, Patrick M; Malaisrie, S C

    2016-01-01

    Background People with atrial fibrillation (AF) often undergo cardiac surgery for other underlying reasons and are frequently offered concomitant AF surgery to reduce the frequency of short- and long-term AF and improve short- and long-term outcomes. Objectives To assess the effects of concomitant AF surgery among people with AF who are undergoing cardiac surgery on short-term and long-term (12 months or greater) health-related outcomes, health-related quality of life, and costs. Search methods Starting from the year when the first “maze” AF surgery was reported (1987), we searched the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library (March 2016), MEDLINE Ovid (March 2016), Embase Ovid (March 2016), Web of Science (March 2016), the Database of Abstracts of Reviews of Effects (DARE, April 2015), and Health Technology Assessment Database (HTA, March 2016). We searched trial registers in April 2016. We used no language restrictions. Selection criteria We included randomised controlled trials evaluating the effect of any concomitant AF surgery compared with no AF surgery among adults with preoperative AF, regardless of symptoms, who were undergoing cardiac surgery for another indication. Data collection and analysis Two review authors independently selected studies and extracted data. We evaluated the risk of bias using the Cochrane ‘Risk of bias’ tool. We included outcome data on all-cause and cardiovascular-specific mortality, freedom from atrial fibrillation, flutter, or tachycardia off antiarrhythmic medications, as measured by patient electrocardiographic monitoring greater than three months after the procedure, procedural safety, 30-day rehospitalisation, need for post-discharge direct current cardioversion, health-related quality of life, and direct costs. We calculated risk ratios (RR) for dichotomous data with 95% confidence intervals (CI) using a fixed-effect model when heterogeneity was low (I2 ≤ 50%) and random

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

    Directory of Open Access Journals (Sweden)

    О. Н. Ганеева

    2015-10-01

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

  13. Suspension Bridge Flutter for Girder with Separate Control Flaps

    DEFF Research Database (Denmark)

    Huynh, T.; Thoft-Christensen, Palle

    Active vibration control of long span suspension bridge flutter using separated control flaps (SFSC) has shown to increase effectively the critical wind speed of bridges. In this paper, an SFSC calculation based on modal equations of the vertical and torsional motions of the bridge girder including...... the flaps is presented. The length of the flaps attached to the girder, the flap configuration and the flap rotational angles are parameters used to increase the critical wind speed of the bridge. To illustrate the theory a numerical example is shown for a suspension bridge of 1000m+2500m+1000m span based...... on the Great Belt Bridge streamlined girder....

  14. New Flutter Analysis Technique for Time-Domain Computational Aeroelasticity

    Science.gov (United States)

    Pak, Chan-Gi; Lung, Shun-Fat

    2017-01-01

    A new time-domain approach for computing flutter speed is presented. Based on the time-history result of aeroelastic simulation, the unknown unsteady aerodynamics model is estimated using a system identification technique. The full aeroelastic model is generated via coupling the estimated unsteady aerodynamic model with the known linear structure model. The critical dynamic pressure is computed and used in the subsequent simulation until the convergence of the critical dynamic pressure is achieved. The proposed method is applied to a benchmark cantilevered rectangular wing.

  15. The influence of trailed vorticity on flutter speed estimations

    DEFF Research Database (Denmark)

    Pirrung, Georg; Aagaard Madsen, Helge; Kim, Taeseong

    2014-01-01

    ) theory, which is coupled with Beddoes' near wake model for trailed vorticity. The first part of this work outlines the implementation in HAWC2, with a focus on the interaction of the induction from the blade based near wake model with the induction from the polar grid based BEM model in HAWC2...... building up at a critical rotor speed. Blades with modified torsional and flapwise stiffness are also investigated. A flutter analysis is often part of the stability investigations for new blades but is normally carried out with engineering models that do not include the influence of unsteady trailed...

  16. Aeroelastic Tailoring of Transport Wings Including Transonic Flutter Constraints

    Science.gov (United States)

    Stanford, Bret K.; Wieseman, Carol D.; Jutte, Christine V.

    2015-01-01

    Several minimum-mass optimization problems are solved to evaluate the effectiveness of a variety of novel tailoring schemes for subsonic transport wings. Aeroelastic stress and panel buckling constraints are imposed across several trimmed static maneuver loads, in addition to a transonic flutter margin constraint, captured with aerodynamic influence coefficient-based tools. Tailoring with metallic thickness variations, functionally graded materials, balanced or unbalanced composite laminates, curvilinear tow steering, and distributed trailing edge control effectors are all found to provide reductions in structural wing mass with varying degrees of success. The question as to whether this wing mass reduction will offset the increased manufacturing cost is left unresolved for each case.

  17. Specialists Meeting on Wing-with-Stores Flutter

    Science.gov (United States)

    1975-04-01

    8217’ gen. = real and imaginary parts of non dimensional generalized airfirces defined for d~ scret values of k =’s V -vg .5, !. a, ’ . . ’’tt...on Fig. 2. The diagrams are set from left to right, in order of increasing values of the C.G. forward shift and from top to bottom, in order of...distorsions of the equal speed lines due to the presence of different flutter modes are evioont. On top of fig. 10 three Rections of these diagrams for a

  18. Identification of frequency domain and time domain aeroelastic parameters for flutter analysis of flexible structures

    Science.gov (United States)

    Chowdhury, Arindam Gan

    Flutter analysis of structures is usually done in frequency domain. Alternately, time-domain methods have been suggested. For frequency-domain flutter analysis, flutter derivatives are used that can be identified from section model testing in the wind tunnel. In time-domain analysis, the frequency-dependent aerodynamic self-excited forces expressed in flutter derivatives acting on the structure can be approximated in the Laplace domain by Rational functions. The art of efficient extraction of these aeroelastic parameters requires an elastic suspension system to capture coupled displacement and aerodynamic force time histories from wind tunnel testing of section models. A novel three-degree-of-freedom (DOF) suspension system has been developed for the wind-tunnel section model study of wind-excited vibrations of flexible structures. The extraction of flutter derivatives becomes more challenging when the number of DOF of section model increases from two to three. Since the work in the field of identifying all eighteen flutter derivatives has been limited, it has motivated the development of a new system identification method (Iterative least squares method or ILS method) to efficiently extract the flutter derivatives using a section model suspended by the three-DOF elastic suspension system. All eighteen flutter derivatives for a streamlined bridge deck and an airfoil section model were identified by using ILS approach. Flutter derivatives related to the lateral DOF were emphasized. For time-domain flutter analysis, Rational function approximation (RFA) approach involves approximation of the experimentally obtained flutter derivatives through 'multilevel linear and nonlinear optimization' procedure. This motivated the formulation of a system identification technique (Experimental extraction of Rational function coefficients or E2RFC) to directly extract the Rational function coefficients from wind tunnel testing. The current formulation requires testing of the model

  19. Atrial fibrillation: inflammation in disguise?

    NARCIS (Netherlands)

    Lappegard, K.T.; Hovland, A.; Pop, G.A.M.; Mollnes, T.E.

    2013-01-01

    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

  20. Atrial fibrillation and female sex.

    Science.gov (United States)

    Anselmino, Matteo; Battaglia, Alberto; Gallo, Cristina; Gili, Sebastiano; Matta, Mario; Castagno, Davide; Ferraris, Federico; Giustetto, Carla; Gaita, Fiorenzo

    2015-12-01

    Atrial fibrillation is the most common supraventricular arrhythmia. Its prevalence increases with age and preferentially affects male patients. Over 75 years of age, however, female patients being more prevalent, the absolute number of patients affected is similar between sexes. Despite this, few data are available in the literature concerning sex-related differences in atrial fibrillation patients. The present systematic review therefore considers comorbidities, referring symptoms, quality of life, pharmacological approaches and trans-catheter ablation in female rather than in male atrial fibrillation patients in search of parameters that may have an impact on the treatment outcome. In brief, female atrial fibrillation patients more commonly present comorbidities, leading to a higher prevalence of persistent atrial fibrillation; moreover, they refer to hospital care later and with a longer disease history. Atrial fibrillation symptoms relate to low quality of life in female patients; in fact, atrial fibrillation paroxysm usually presents higher heart rate, leading to preferentially adopt a rate rather than a rhythm-control strategy. Female atrial fibrillation patients present an increased risk of stroke, worsened by the lower oral anticoagulant prescription rate related to the concomitant higher haemorrhagic risk profile. Trans-catheter ablation is under-used in female patients and, on the contrary, they are more commonly affected by anti-arrhythmic drug side effects.

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

    Science.gov (United States)

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

    2017-03-14

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

  2. Catheter ablation of three macroreentrant atrial tachycardias after surgical repair of Double-Outlet Right Ventricle

    Directory of Open Access Journals (Sweden)

    Tadashi Wada

    2012-06-01

    Full Text Available A 54-year-old man with a surgically repaired double-outlet right ventricle (DORV presented with palpitations and worsening right heart failure. His 12-lead ECG showed atrial tachycardia (AT with an atrial cycle length (CL of 300 ms and an inverted saw-tooth F-wave pattern in the inferior leads II, III, and aVF typical of atrial flutter. Electrophysiological study and radiofrequency catheter ablation were performed. A total of 3 sustained ATs (AT1–AT3 were induced. Using the electroanatomical mapping system, CARTO3, and conventional mapping techniques, the ATs were identified as macroreentrant tachycardias circling around an incisional line on the free wall of the right atrium (AT1, the tricuspid annulus (AT2, and low voltage area in the lateral wall including the right septum (AT3. Accuracy of CARTO3 in three-dimensional reconstruction was sufficient to elucidate anatomical features (including catheter sites, incision, and low voltage areas and macroreentrant circuits. However, conventional mapping techniques were also necessary to identify the mechanism of the tachycardias, and therefore to eliminate all of them successfully. This case demonstrates that the use of combined conventional and electroanatomical mapping techniques, such as CARTO3, can be helpful in identifying the critical isthmus for catheter ablation of macroreentrant AT in patients with surgically corrected congenital heart disease (CHD.

  3. Tratamiento quirúrgico curativo de la fibrilación atrial mediante técnica de ablación con radiofrecuencia monopolar irrigada: resultados a corto y mediano plazo Surgical treatment of atrial fibrillation through irrigated ablation with monopolar radiofrequency: results to short and midterm

    Directory of Open Access Journals (Sweden)

    Sergio Franco

    2007-02-01

    Full Text Available No existe una publicación colombiana con seguimiento a mediano plazo acerca del uso de esta técnica. Objetivo: evaluar el tratamiento quirúrgico de la fibrilación auricular a través de radiofrecuencia monopolar irrigada, mediante el seguimiento clínico, electrocardiográfico y ecocardiográfico a corto y mediano plazo. Métodos: entre septiembre de 2003 y octubre de 2005, se evaluaron de manera prospectiva, 70 pacientes con diagnóstico de fibrilación atrial y otra patología cardiaca que requería intervención quirúrgica. Se utilizó el sistema de ablación por radiofrecuencia monopolar Cardioblate® (Medtronic, Inc.. Los resultados se analizaron en un paquete estadístico SPSS versión 11,0. Resultados: se reclutaron 70 pacientes, 52% de género femenino y 48% masculino, con edad promedio de 54 años y fracción de expulsión preoperatoria del 47%. Se halló insuficiencia mitral (49% y estenosis mitral (26% como principales causas de cirugía cardiaca primaria. Se evaluaron 87% de los pacientes a 18 meses (3 y 25. Se logró la curación de la arritmia en el 88% de ellos. Las arritmias residuales en este grupo fueron fibrilación auricular (6% y flutter atrial (6%. El 80% de las arritmias post-operatorias se encuentran durante los primeros quince días de la cirugía; las más frecuentes fueron fibrilación atrial y flutter atrial. Se suspendió la anticoagulación y la medicación antiarrítmica en el 89% y 90% de los pacientes respectivamente. La técnica quirúrgica utilizada no generó complicaciones inherentes a la misma. Conclusión: esta investigación demostró que la técnica de ablación quirúrgica de la fibrilación auricular con radiofrecuencia monopolar irrigada, es fácilmente reproducible, altamente efectiva y segura para el paciente.There is not any publication about the use of this technique with midterm follow-up in Colombia. Objective: to evaluate the surgical treatment of atrial fibrillation with the use of

  4. An Interactive Software for Conceptual Wing Flutter Analysis and Parametric Study

    Science.gov (United States)

    Mukhopadhyay, Vivek

    1996-01-01

    An interactive computer program was developed for wing flutter analysis in the conceptual design stage. The objective was to estimate the flutter instability boundary of a flexible cantilever wing, when well-defined structural and aerodynamic data are not available, and then study the effect of change in Mach number, dynamic pressure, torsional frequency, sweep, mass ratio, aspect ratio, taper ratio, center of gravity, and pitch inertia, to guide the development of the concept. The software was developed for Macintosh or IBM compatible personal computers, on MathCad application software with integrated documentation, graphics, data base and symbolic mathematics. The analysis method was based on non-dimensional parametric plots of two primary flutter parameters, namely Regier number and Flutter number, with normalization factors based on torsional stiffness, sweep, mass ratio, taper ratio, aspect ratio, center of gravity location and pitch inertia radius of gyration. The parametric plots were compiled in a Vought Corporation report from a vast data base of past experiments and wind-tunnel tests. The computer program was utilized for flutter analysis of the outer wing of a Blended-Wing-Body concept, proposed by McDonnell Douglas Corp. Using a set of assumed data, preliminary flutter boundary and flutter dynamic pressure variation with altitude, Mach number and torsional stiffness were determined.

  5. Experimental Methods Applied in a Study of Stall Flutter in an Axial Flow Fan

    Directory of Open Access Journals (Sweden)

    John D. Gill

    2004-01-01

    Full Text Available Flutter testing is an integral part of aircraft gas turbine engine development. In typical flutter testing blade mounted sensors in the form of strain gages and casing mounted sensors in the form of light probes (NSMS are used. Casing mounted sensors have the advantage of being non-intrusive and can detect the vibratory response of each rotating blade. Other types of casing mounted sensors can also be used to detect flutter of rotating blades. In this investigation casing mounted high frequency response pressure transducers are used to characterize the part-speed stall flutter response of a single stage unshrouded axial-flow fan. These dynamic pressure transducers are evenly spaced around the circumference at a constant axial location upstream of the fan blade leading edge plane. The pre-recorded experimental data at 70% corrected speed is analyzed for the case where the fan is back-pressured into the stall flutter zone. The experimental data is analyzed using two probe and multi-probe techniques. The analysis techniques for each method are presented. Results from these two analysis methods indicate that flutter occurred at a frequency of 411 Hz with a dominant nodal diameter of 2. The multi-probe analysis technique is a valuable method that can be used to investigate the initiation of flutter in turbomachines.

  6. Flutter of wings involving a locally distributed flexible control surface

    Science.gov (United States)

    Mozaffari-Jovin, S.; Firouz-Abadi, R. D.; Roshanian, J.

    2015-11-01

    This paper undertakes to facilitate appraisal of aeroelastic interaction of a locally distributed, flap-type control surface with aircraft wings operating in a subsonic potential flow field. The extended Hamilton's principle serves as a framework to ascertain the Euler-Lagrange equations for coupled bending-torsional-flap vibration. An analytical solution to this boundary-value problem is then accomplished by assumed modes and the extended Galerkin's method. The developed aeroelastic model considers both the inherent flexibility of the control surface displaced on the wing and the inertial coupling between these two flexible bodies. The structural deformations also obey the Euler-Bernoulli beam theory, along with the Kelvin-Voigt viscoelastic constitutive law. Meanwhile, the unsteady thin-airfoil and strip theories are the tools of producing the three-dimensional airloads. The origin of aerodynamic instability undergoes analysis in light of the oscillatory loads as well as the loads owing to arbitrary motions. After successful verification of the model, a systematic flutter survey was conducted on the theoretical effects of various control surface parameters. The results obtained demonstrate that the flapping modes and parameters of the control surface can significantly impact the flutter characteristics of the wings, which leads to a series of pertinent conclusions.

  7. Aeroelastic flutter energy harvesters self-polarized by triboelectric effects

    Science.gov (United States)

    Perez, M.; Boisseau, S.; Geisler, M.; Gasnier, P.; Willemin, J.; Despesse, G.; Reboud, J. L.

    2018-01-01

    This paper presents the performances of several electrostatic flutter energy harvesters tested in a wind tunnel between 0 and 20 m s‑1. The main idea is to use the flutter capability of thin flexible films confined between lateral walls to induce simultaneously the capacitance variations and the electrostatic polarization required by the triboelectric/electrostatic conversion. This technology provides thin and flexible devices and solve the electret’s stability issue (Perez et al 2015 Smart Mater. Struct., Perez et al 2015 New Circuits and Systems). Our prototypes (electrical power-flux density from 0.35 μW cm‑2@3 m s‑1 (light breeze) to 35 μW cm‑2@20 m s‑1 (fresh gale). A Maximum Power Point circuit has been developed to efficiently use the power provided by the energy harvesters. The energy harvester combined with its power management circuit has finally been used to supply an 868 MHz wireless sensor node with temperature and acceleration measurements, validating the complete energy harvesting chain.

  8. Dementia and Atrial Fibrillation

    DEFF Research Database (Denmark)

    Pastori, Daniele; Miyazawa, Kazuo; Lip, Gregory Y H

    2018-01-01

    The risk of developing dementia is increased in patients with atrial fibrillation (AF), with the incidence of both conditions increasing with aging. Patients with dementia frequently do not receiving adequate thrombo-prophylaxis, because of the inability to monitor INR and/or to achieve...... in therapeutic range during VKAs therapy, the assessment of cognitive impairment may help identify those patients who may benefit from switching to NOACs. In conclusion, patients with AF and dementia benefit from anticoagulation and should not be denied receiving adequate stroke prevention. Cognitive function...

  9. [Recurrent left atrial myxoma].

    Science.gov (United States)

    Moreno Martínez, Francisco L; Lagomasino Hidalgo, Alvaro; Mirabal Rodríguez, Roger; López Bermúdez, Félix H; López Bernal, Omaida J

    2003-01-01

    Primary cardiac tumors are rare. Mixomas are the most common among them; 75% are located in the left atrium, 20% in the right atrium, and the rest in the ventricles. The seldom appear in atrio-ventricular valves. Recidivant mixoma are also rare, appearing in 1-5% of all patients that have undergone surgical treatment of a mixoma. In this paper we present our experience with a female patient, who 8 years after having been operated of a left atrial mixoma, began with symptoms of mild heart failure. Transthoracic echocardiography revealed recurrence of the tumor, and was therefore subjected to a second open-heart surgery from which she recovered without complications.

  10. Nonlinear dynamics approach of modeling the bifurcation for aircraft wing flutter in transonic speed

    DEFF Research Database (Denmark)

    Matsushita, Hiroshi; Miyata, T.; Christiansen, Lasse Engbo

    2002-01-01

    The procedure of obtaining the two-degrees-of-freedom, finite dimensional. nonlinear mathematical model. which models the nonlinear features of aircraft flutter in transonic speed is reported. The model enables to explain every feature of the transonic flutter data of the wind tunnel tests...... conducted at National Aerospace Laboratory in Japan for a high aspect ratio wing. It explains the nonlinear features of the transonic flutter such as the subcritical Hopf bifurcation of a limit cycle oscillation (LCO), a saddle-node bifurcation, and an unstable limit cycle as well as a normal (linear...

  11. LCO flutter of cantilevered woven glass/epoxy laminate in subsonic flow

    Science.gov (United States)

    Majid, Dayang Laila Abang Haji Abdul; Basri, Shahnor

    2008-02-01

    The paper presents aeroelastic characteristics of a cantilevered composite wing, idealized as a composite flat plate laminate. The composite laminate was made from woven glass fibers with epoxy matrix. The elastic and dynamic properties of the laminate were determined experimentally for aeroelastic calculations. Aeroelastic wind tunnel testing of the laminate was performed and the result showed that flutter, a dynamic instability occurred. The cantilevered laminate also displayed limit cycle amplitude, post-flutter oscillation. The experimental flutter velocity and frequency were verified by our computational analysis.

  12. A Conceptual Wing Flutter Analysis Tool for Systems Analysis and Parametric Design Study

    Science.gov (United States)

    Mukhopadhyay, Vivek

    2003-01-01

    An interactive computer program was developed for wing flutter analysis in the conceptual design stage. The objective was to estimate flutt er instability boundaries of a typical wing, when detailed structural and aerodynamic data are not available. Effects of change in key flu tter parameters can also be estimated in order to guide the conceptual design. This userfriendly software was developed using MathCad and M atlab codes. The analysis method was based on non-dimensional paramet ric plots of two primary flutter parameters, namely Regier number and Flutter number, with normalization factors based on wing torsion stiffness, sweep, mass ratio, taper ratio, aspect ratio, center of gravit y location and pitch-inertia radius of gyration. These parametric plo ts were compiled in a Chance-Vought Corporation report from database of past experiments and wind tunnel test results. An example was prese nted for conceptual flutter analysis of outer-wing of a Blended-Wing- Body aircraft.

  13. Successful Treatment of Tardive Diaphragmatic Flutter in an Elderly Man with Aripiprazole

    Directory of Open Access Journals (Sweden)

    Yi-Hsiang Chen

    2013-06-01

    Full Text Available Tardive dyskinesia (TD is a severe adverse effect induced by prolonged treatment with antipsychotics. The development of TD is usually associated with advanced age, female sex, prior extrapyramidal adverse effects, and a longer duration or an intermittent course of antipsychotic treatment. Older age, however, is the most robust risk factor for TD. Tardive diaphragmatic flutter is an uncommon form of TD and may lead to great distress in the patient's life. No effective treatment advice for tardive diaphragmatic flutter has been suggested. We herein report the case of a 65-year-old male with bipolar disorder who suffered from tardive diaphragmatic flutter associated with the long-term usage of risperidone. The diaphragmatic flutter remitted for 2 years under the monotherapy with aripiprazole. Potential mechanisms, such as the dopamine stabilization in aripiprazole, are discussed.

  14. Influence of structural backlash and friction in command system on the aircraft flutter

    Directory of Open Access Journals (Sweden)

    Maričič N.

    2004-01-01

    Full Text Available Experience has shown that aircraft structures are generally affected by structural nonlinearities. The focus in this paper is concentrated on backlash and friction described in hysteresis loop of the classical aircraft command systems and their influence on flutter of aircraft. Based on AGARD No. 665 in paper is done nonlinear flutter velocity analysis in function of backlash and friction in the classical command system of aircraft. Unsteady aerodynamic forces are calculated based on well known Doublet- Lattice Method (DLM. Structural input data are taken from AGARD No. 665. Flutter eigenvalues are obtained by modified k-method. The flutter model of nonlinear aircraft structure is developed on base of harmonic linearization. The aim of paper is to achieve useful and relatively reliable tool for critical observations on different recommendations given in the various airworthiness regulations for nonlinear characteristics of hysteresis loops in the classical command systems of aircrafts. .

  15. Experimental Model Based Feedback Control for Flutter Suppression and Gust Load Alleviation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc. (ZONA) proposes an R&D effort to develop an Experimental Model Based Feedback Control (EMBFC) Framework for the flutter suppression and...

  16. Underestimation of the incidence of new-onset post-coronary artery bypass grafting atrial fibrillation and its impact on 30-day mortality.

    Science.gov (United States)

    Filardo, Giovanni; Pollock, Benjamin D; da Graca, Briget; Phan, Teresa K; Sass, Danielle M; Ailawadi, Gorav; Thourani, Vinod; Damiano, Ralph

    2017-10-01

    Inconsistent definitions of atrial fibrillation after coronary artery bypass grafting have caused uncertainty about its incidence and risk. We examined the extent to which limiting the definition to post-coronary artery bypass grafting atrial fibrillation events requiring treatment underestimates its incidence and impact on 30-day mortality. We assessed in-hospital atrial fibrillation and 30-day mortality in 9268 consecutive patients without preoperative atrial fibrillation who underwent isolated coronary artery bypass grafting at 5 US hospitals (2004-2010). Patients who experienced 1 or more episode of post-coronary artery bypass grafting atrial fibrillation detected via continuous in-hospital electrocardiogram/telemetry monitoring were divided into those for whom Society of Thoracic Surgeons data (applying the definition "atrial fibrillation/flutter requiring treatment") also indicated atrial fibrillation versus those for whom it did not. Risk-adjusted 30-day mortality was compared between these 2 groups and with patients without post-coronary artery bypass grafting atrial fibrillation. Risk-adjusted incidence of post-coronary artery bypass grafting atrial fibrillation incidence was 33.4% (27.0% recorded in Society of Thoracic Surgeons data, 6.4% missed). Patients with post-coronary artery bypass grafting atrial fibrillation missed by Society of Thoracic Surgeons data had a significantly greater risk of 30-day mortality (odds ratio, 2.08, 95% confidence interval, 1.17-3.69) than those captured. By applying the significant underestimation of post-coronary artery bypass grafting atrial fibrillation incidence we observed (odds ratio [Society of Thoracic Surgeons vs missed], 0.78; 95% confidence interval, 0.72-0.83) to the approximately 150,000 patients undergoing isolated coronary artery bypass grafting in the United States each year estimates this increased risk of mortality is carried by 9600 patients (95% confidence interval, 9420-9780) annually. Defining post

  17. Expanding a flutter envelope using data from accelerating flight: Application to the F-16 fighter aircraft

    Science.gov (United States)

    Harris, Charles A.

    Due to the destructive nature of flutter, flutter testing is a mandatory requirement for certification of both civilian and military aircraft. However, along with the complexity of newer aircraft, the time and cost associated with flutter testing has increased dramatically. Considering that many of the test techniques and analysis methods used to perform flutter testing date back to the 1950s and 1960's it may be time to take a fresh look at how flutter testing can best be accomplished. This thesis revisits flutter testing techniques and proposes an alternative to traditional flutter testing. The alternative uses flight test data from an aircraft that is performing an acceleration to clear the flutter envelope of the aircraft. Four academic issues arise from this new test approach. (1) Are frequencies and dampings affected by the acceleration of the aircraft? (2) Can parameter identification algorithms extract frequency and damping values from the time varying data? (3) Can the vibration response at airspeeds (or Mach numbers) beyond which the aircraft has accelerated be anticipated? (4) What formal criteria can be used to determine when the aircraft needs to end the acceleration and terminate the test point? The academic contribution of this thesis is to address these issues. It is shown that although the frequencies and damping values do change the change is so small that it is irrelevant. It is also shown that by taking small windows of data, within which the change in parameters is small, it is possible to accurately identify parameters from the time varying data. Finally it is shown that at least in principal parameters can be predicted using data from sub-critical airspeeds, and that testing can be discontinued before an unstable flight condition is reached.

  18. Coupled-Mode Flutter of Wind Turbines and its Suppression Using Torsional Viscous Damper

    DEFF Research Database (Denmark)

    Zhang, Zili; Chen, Bei; Nielsen, Søren R. K.

    2017-01-01

    The trend towards lighter and more flexible blades may lead to aeroelastic instability of wind turbines under certain circumstances, resulting in rapid destructive failure or limit-cycle oscillations of the structural components. For pitch-regulated wind turbines, classical flutter is believed to...... to be about 1.6 times its nominal rotational speed. A novel torsional viscous damper is then proposed to suppress torsional blade vibration and to enhance flutter stability of wind turbines....

  19. Non-linear Phenomena of Wing Flutter and the Effect of Laminar-Turbulent Transition

    Science.gov (United States)

    Marti, Ferran

    A Navier-Stokes Computational Fluid Dynamics (CFD) code is coupled with a Computa- tional Structural Dynamics (CSD) code to study the flutter boundary of the NACA64A010 airfoil using Isogai's structural model in transonic conditions. This model simulates aeroelas- tic conditions on a sweptback wing. A well-known feature, only present in the inviscid flutter boundary of this airfoil, is the existence of multiple flutter points for a fixed freestream Mach number. The fully-turbulent flutter boundary has not been studied by many researchers us- ing a Reynolds-Averaged Navier-Stokes approach. In the present study, the fully-turbulent flutter boundary reveals the existence of multiple equilibrium positions for a narrow range of flight conditions. The system moves away from the initial equilibrium position, finding a new set of equilibrium points and oscillating around it. This new set of equilibrium points reveals as stable or unstable for different structural properties of the wing. We then proceed to study the effect of turbulent transition on flutter boundary. A laminar- to-turbulent transition model is implemented in the CFD code and validated. The effect of using a free-transition CFD code vs. a fully-turbulent approach is evaluated on three airfoils with different characteristics for subsonic and transonic conditions. While free-transition does not affect the pressure distribution at subsonic conditions, the transonic simulations reveal a change in the shock-wave position when laminar-turbulent effects are included. The effect of transition on the flutter boundary of the NACA64A010 airfoil at transonic conditions is then investigated. A comparison between the free-transition, inviscid and fully-turbulent flutter boundaries reveals similarities between the inviscid and free-transition elastic re- sponses. Those similarities are due to the shift in the fully-turbulent shock-wave position, when accounting for free-transition effects, moving closer to the inviscid

  20. Stability analysis of nonlinear autonomous systems - General theory and application to flutter

    Science.gov (United States)

    Smith, L. L.; Morino, L.

    1975-01-01

    The analysis makes use of a singular perturbation method, the multiple time scaling. Concepts of stable and unstable limit cycles are introduced. The solution is obtained in the form of an asymptotic expansion. Numerical results are presented for the nonlinear flutter of panels and airfoils in supersonic flow. The approach used is an extension of a method for analyzing nonlinear panel flutter reported by Morino (1969).

  1. Robust Multivariable Flutter Suppression for the Benchmark Active Control Technology (BACT) Wind-Tunnel Model

    Science.gov (United States)

    Waszak, Martin R.

    1997-01-01

    The Benchmark Active Controls Technology (BACT) project is part of NASA Langley Research Center s Benchmark Models Program for studying transonic aeroelastic phenomena. In January of 1996 the BACT wind-tunnel model was used to successfully demonstrate the application of robust multivariable control design methods (H and -synthesis) to flutter suppression. This paper addresses the design and experimental evaluation of robust multivariable flutter suppression control laws with particular attention paid to the degree to which stability and performance robustness was achieved.

  2. Effects of structural coupling on mistuned cascade flutter and response

    Science.gov (United States)

    Kielb, R. E.; Kaza, K. R. V.

    1983-01-01

    The effects of structural coupling on mistuned cascade flutter and response are analytically investigated using an extended typical section model. This model includes both structural and aerodynamic coupling between the blades. The model assumes that the structurally coupled system natural modes were determined and are represented in the form of N bending and N torsional uncoupled modes for each blade, where N is the number of blades and, hence, is only valid for blade dominated motion. The aerodynamic loads are calculated by using two dimensional unsteady cascade theories in the subsonic and supersonic flow regimes. The results show that the addition of structural coupling can affect both the aeroelastic stability and frequency. The stability is significantly affected only when the system is mistuned. The resonant frequencies can be significantly changed by structural coupling in both tuned and mistuned systems, however, the peak response is significantly affected only in the latter.

  3. Screening for Atrial Fibrillation

    DEFF Research Database (Denmark)

    Freedman, Ben; Camm, A. John; Calkins, Hugh

    2017-01-01

    in September 2015 to promote discussion and research about AF screening as a strategy to reduce stroke and death and to provide advocacy for implementation of country-specific AF screening programs. During 2016, 60 expert members of AF-SCREEN, including physicians, nurses, allied health professionals, health......Approximately 10% of ischemic strokes are associated with atrial fibrillation (AF) first diagnosed at the time of stroke. Detecting asymptomatic AF would provide an opportunity to prevent these strokes by instituting appropriate anticoagulation. The AF-SCREEN international collaboration was formed...... or by intermittent ECG recordings over 2 weeks is not a benign condition and, with additional stroke factors, carries sufficient risk of stroke to justify consideration of anticoagulation. With regard to the methods of mass screening, handheld ECG devices have the advantage of providing a verifiable ECG trace...

  4. Pressure measurements on a rectangular wing with a NACA0012 airfoil during conventional flutter

    Science.gov (United States)

    Rivera, Jose A., Jr.; Dansberry, Bryan E.; Durham, Michael H.; Bennett, Robert M.; Silva, Walter A.

    1992-01-01

    The Structural Dynamics Division at NASA LaRC has started a wind tunnel activity referred to as the Benchmark Models Program. The primary objective of the program is to acquire measured dynamic instability and corresponding pressure data that will be useful for developing and evaluating aeroelastic type CFD codes currently in use or under development. The program is a multi-year activity that will involve testing of several different models to investigate various aeroelastic phenomena. The first model consisted of a rigid semispan wing having a rectangular planform and a NACA 0012 airfoil shape which was mounted on a flexible two degree-of-freedom mount system. Two wind-tunnel tests were conducted with the first model. Several dynamic instability boundaries were investigated such as a conventional flutter boundary, a transonic plunge instability region near Mach = 0.90, and stall flutter. In addition, wing surface unsteady pressure data were acquired along two model chords located at the 60 to 95-percent span stations during these instabilities. At this time, only the pressure data for the conventional flutter boundary is presented. The conventional flutter boundary and the wing surface unsteady pressure measurements obtained at the conventional flutter boundary test conditions in pressure coefficient form are presented. Wing surface steady pressure measurements obtained with the model mount system rigidized are also presented. These steady pressure data were acquired at essentially the same dynamic pressure at which conventional flutter had been encountered with the mount system flexible.

  5. Idiopathic giant right atrial aneurysm

    Science.gov (United States)

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

    2013-01-01

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

  6. P wave area for quantitative electrocardiographic assessment of left atrial remodeling.

    Directory of Open Access Journals (Sweden)

    Jonathan W Weinsaft

    Full Text Available BACKGROUND: Left atrial (LA dilation provides a substrate for mitral regurgitation (MR and atrial arrhythmias. ECG can screen for LA dilation but standard approaches do not assess LA geometry as a continuum, as does non-invasive imaging. This study tested ECG-quantified P wave area as an index of LA geometry. METHODS AND RESULTS: 342 patients with CAD underwent ECG and CMR within 7 (0.1±1.4 days. LA area on CMR correlated best with P wave area in ECG lead V1 (r = 0.42, p<0.001, with lesser correlations for P wave amplitude and duration. P wave area increased stepwise in relation to CMR-evidenced MR severity (p<0.001, with similar results for MR on echocardiography (performed in 86% of patients. Pulmonary arterial (PA pressure on echo was increased by 50% among patients in the highest (45±14 mmHg vs. the lowest (31±9 mmHg P wave area quartile of the population. In multivariate regression, CMR and echo-specific models demonstrated P wave area to be independently associated with LA size after controlling for MR, as well as echo-evidenced PA pressure. Clinical follow-up (mean 2.4±1.9 years demonstrated ECG and CMR to yield similar results for stratification of arrhythmic risk, with a 2.6-fold increase in risk for atrial fibrillation/flutter among patients in the top P wave area quartile of the population (CI 1.1-5.9, p = 0.02, and a 3.2-fold increase among patients in the top LA area quartile (CI 1.4-7.0, p = 0.005. CONCLUSIONS: ECG-quantified P wave area provides an index of LA remodeling that parallels CMR-evidenced LA chamber geometry, and provides similar predictive value for stratification of atrial arrhythmic risk.

  7. Temporary esophageal stenting allows healing of esophageal perforations following atrial fibrillation ablation procedures.

    Science.gov (United States)

    Bunch, T Jared; Nelson, Jennifer; Foley, Tom; Allison, Scott; Crandall, Brian G; Osborn, Jeffrey S; Weiss, J Peter; Anderson, Jeffrey L; Nielsen, Peter; Anderson, Lars; Lappe, Donald L; Day, John D

    2006-04-01

    Left atrial catheter ablation (LACA) has emerged as a successful method to eliminate atrial fibrillation (AF). Recent reports have described atrio-esophageal fistulas, often resulting in death, from this procedure. Temporary esophageal stenting is an established therapy for malignant esophageal disease. We describe the first case of successful temporary esophageal stenting for an esophageal perforation following LACA. A 48-year-old man with symptomatic drug refractory lone AF underwent an uneventful LACA. Fifty-nine ablations with an 8-mm tip ablation catheter (30 seconds, 70 Watts, 55 degrees C), as guided by 3-D NavX mapping, were performed in the left atrium to isolate the pulmonary veins as well as a left atrial flutter and roof ablation line. In addition, complex atrial electrograms in AF and sites of vagal innervation were ablated. Two weeks later, he presented with sub-sternal chest pain, fever, and dysphagia. A chest CT showed a 3-mm esophageal perforation at the level of the left atrium with mediastinal soiling and no pericardial effusion. An urgent upper endoscopy with placement of a PolyFlex removable esophageal stent to seal off the esophago-mediastinal fistula was performed. After 3 weeks of i.v. antibiotics, naso-jejunal tube feedings, and esophageal stenting, the perforation resolved and the stent was removed. Over 18 months of follow-up, there have been no other complications, and he has returned to a physically active life and remains free from AF on previously ineffective anti-arrhythmic drugs. Early diagnosis of esophageal perforations following LACA may allow temporary esophageal stenting with successful esophageal healing. Prompt chest CT scans with oral and i.v. contrast should be considered in any patient with sub-sternal chest pain or dysphagia following LACA.

  8. Wind-tunnel evaluation of NASA developed control laws for flutter suppression on a DC-10 derivative wing

    Science.gov (United States)

    Abel, I.; Newsom, J. R.

    1981-01-01

    Two flutter suppression control laws were synthesized, implemented, and tested on a low speed aeroelastic wing model of a DC-10 derivative. The methodology used to design the control laws is described. Both control laws demonstrated increases in flutter speed in excess of 25 percent above the passive wing flutter speed. The effect of variations in gain and phase on the closed loop performance was measured and compared with analytical predictions. The analytical results are in good agreement with experimental data.

  9. Physics-Based Identification, Modeling and Risk Management for Aeroelastic Flutter and Limit-Cycle Oscillations (LCO) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed research program will develop a physics-based identification, modeling and risk management infrastructure for aeroelastic transonic flutter and...

  10. Comparison of analytical and wind-tunnel results for flutter and gust response of a transport wing with active controls

    Science.gov (United States)

    Abel, I.; Perry, B., III; Newsom, J. R.

    1982-01-01

    Two flutter suppression control laws wre designed and tested on a low speed aeroelastic model of a DC-10 derivative wing. Both control laws demontrated increases in flutter speed in excess of 25 percent above the passive wing flutter speed. In addition, one of the control laws was effective in reducing loads due to turbulence generated in the wind tunnel. The effect of variations in gain and phase on the closed-loop performance was measured and is compared with predictions. In general, both flutter and gust response predictions agree reasonably well with experimental data.

  11. Parametric study on supersonic flutter of angle-ply laminated plates using shear deformable finite element method

    Science.gov (United States)

    Xia, Wei; Ni, Qiao

    2011-10-01

    The influence of fiber orientation, flow yaw angle and length-to-thickness ratio on flutter characteristics of angle-ply laminated plates in supersonic flow is studied by finite element approach. The structural model is established using the Reissner-Mindlin theory in which the transverse shear deformation is considered. The aerodynamic pressure is evaluated by the quasi-steady first-order piston theory. The equations of motion are formulated based on the principle of virtual work. With the harmonic motion assumption, the flutter boundary is determined by solving a series of complex eigenvalue problems. Numerical study shows that (1) The flutter dynamic pressure and the coalescence of flutter modes depend on fiber orientation, flow yaw angle and length-to-thickness ratio; (2) The laminated plate with all fibers aligned with the flow direction gives the highest flutter dynamic pressure, but a slight yawing of the flow from the fiber orientation results in a sharp decrease of the flutter dynamic pressure; (3) The angle-ply laminated plate with fiber orientation angle equal to flow yaw angle gives high flutter dynamic pressure, but not the maximum flutter dynamic pressure; (4) With the decrease of length-to-thickness ratio, an adverse effect due to mode transition on the flutter dynamic pressure is found.

  12. Active Atrial Function and Atrial Scar Burden After Multiple Catheter Ablations of Persistent Atrial Fibrillation.

    Science.gov (United States)

    Nührich, Jana M; Geisler, Anne C; Steven, Daniel; Hoffmann, Boris A; Schäffer, Benjamin; Lund, Gunnar; Stehning, Christian; Radunski, Ulf K; Sultan, Arian; Schwarzl, Michael; Adam, Gerhard; Willems, Stephan; Muellerleile, Kai

    2017-02-01

    Extensive and repeated substrate modification (SM) is frequently performed as an ablation strategy in persistent atrial fibrillation (persAF). The effect of these extended ablation strategies on atrial function has not been investigated sufficiently so far. The purpose was to assess atrial function by cardiac magnetic resonance (CMR) and its association with left atrial (LA) scar burden by electroanatomical voltage-mapping after multiple persAF ablation procedures. We included 16 persAF patients who had ≥2 SM procedures and a control group (CG) of 21 persAF patients without prior ablation. CMR was performed in sinus rhythm at least 4 weeks after the last cardioversion. Active left and right (RA) atrial emptying fractions (AEF) as well as peak active left atrial appendage (LAA) emptying velocities were obtained by CMR flow measurements. Furthermore, LA scar burden was quantified on electroanatomical voltage maps by the portion of points with local voltage amplitude scar burden to be higher (40 [20-68] vs nine [3-18] %, P scar burden after multiple extensive persAF ablations. ©2016 Wiley Periodicals, Inc.

  13. Atrial natriuretic peptides during experimental atrial tachycardia : Role of developing tachycardiomyopathy

    NARCIS (Netherlands)

    Schoonderwoerd, BA; Crijns, HJGM; Van Veldhuisen, DJ; Boomsma, F; Van den Berg, MP; Bel, KJ; Van Gelder, IC

    Atrial Natriuretic Peptides During Tachycardiomyopathy. Introduction: Atrial tachycardia and chronic heart failure (CHF) are associated with elevated levels of atrial natriuretic peptide (ANP) and its amino terminal part NT-ANP. Chronic high atrial rates may cause CHF due to a rapid ventricular

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

    African Journals Online (AJOL)

    AJB SERVER

    2006-12-29

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

  15. Atrial fibrillation in KCNE1-null mice

    NARCIS (Netherlands)

    Temple, Joel; Frias, Patricio; Rottman, Jeffrey; Yang, Tao; Wu, Yuejin; Verheijck, E. Etienne; Zhang, Wei; Siprachanh, Chanthaphaychith; Kanki, Hideaki; Atkinson, James B.; King, Paul; Anderson, Mark E.; Kupershmidt, Sabina; Roden, Dan M.

    2005-01-01

    Although atrial fibrillation is the most common serious cardiac arrhythmia, the fundamental molecular pathways remain undefined. Mutations in KCNQ1, one component of a sympathetically activated cardiac potassium channel complex, cause familial atrial fibrillation, although the mechanisms in vivo are

  16. Intracardiac echo-guided radiofrequency catheter ablation of atrial fibrillation in patients with atrial septal defect or patent foramen ovale repair: a feasibility, safety, and efficacy study.

    Science.gov (United States)

    Lakkireddy, Dhanunjaya; Rangisetty, Umamahesh; Prasad, Subramanya; Verma, Atul; Biria, Mazda; Berenbom, Loren; Pimentel, Rhea; Emert, Martin; Rosamond, Thomas; Fahmy, Tamer; Patel, Dimpi; Di Biase, Luigi; Schweikert, Robert; Burkhardt, David; Natale, Andrea

    2008-11-01

    Intracardiac Echo-Guided Radiofrequency Catheter. Patients with atrial septal defect (ASD) are at higher risk for atrial fibrillation (AF) even after repair. Transseptal access in these patients is perceived to be difficult. We describe the feasibility, safety, and efficacy of pulmonary vein antral isolation (PVAI) in these patients. We prospectively compared post-ASD/patent foramen ovale (PFO) repair patients (group I, n = 45) with age-gender-AF type matched controls (group II, n = 45). All the patients underwent PVAI through a double transseptal puncture with a roving circular mapping catheter technique guided by intracardiac echocardiography (ICE). The short-term (3 months) and long-term (12 month) failure rates were assessed. In group I, 23 (51%) had percutaneous closure devices and 22 (49%) had a surgical closure. There was no significant difference between group I and II in the baseline characteristics. Intracardiac echo-guided double transseptal access was obtained in 98% of patients in group I and in 100% of patients in group II. PVAI was performed in all patients, with right atrial flutter ablation in 7 patients in group I and in 4 patients in group II. Over a mean follow-up of 15 +/- 4 months, group I had higher short-term (18% vs 13%, P = 0.77) and long-term recurrence (24% vs 18%, P = 0.6) than group II. There was no significant difference in the perioperative complications between the two groups. Echocardiography at 3 months showed interatrial communication in 2 patients in group I and 1 patient in group II, which resolved at 12 months. Percutaneous AF ablation using double transseptal access is feasible, safe, and efficacious in patients with ASD and PFO repairs.

  17. Overweight and obesity as risk factors for atrial fibrillation or flutter: The Danish Diet, Cancer, and Health Study

    National Research Council Canada - National Science Library

    Frost, Lars; Hune, Lone Juul; Vestergaard, Peter

    2005-01-01

    ...) in the Danish Diet, Cancer, and Health Study. Subjects were followed up in the Danish National Registry of Patients and in the Danish Civil Registration System. During follow-up (mean, 5.7 years...

  18. Whirl flutter optimisation-based solution of twin turboprop aircraft using a full-span model

    Directory of Open Access Journals (Sweden)

    Čečrdle J.

    2017-06-01

    Full Text Available Whirl flutter is a specific type of flutter instability, relevant for turboprop aircraft, caused by the effect of rotating parts as a propeller or a gas-turbine engine rotor. The proposed optimisation-based analytical procedure is used to determine the critical values of the engine attachment stiffness parameters for the preselected flutter speed. For the half-span model, two design variables are used. The objective function is defined as the minimization of the engine vibration mode frequency sum. Design constraints keep the engine frequency ratio and the flutter stability at the selected velocity. However, application of a full-span model is necessary in some cases. In this case, special models of both symmetric and antisymmetric engine vibrations and four design variables must be used. Design constraints maintain the pitch mode frequency ratio, the yaw mode frequency ratio and the critical mode frequency ratio. Critical modes are dependent on the relation between the rotational direction of both propellers (identical or inverse. A flutter design constraint is applied as well. The described methodology is demonstrated on the application example of a twin-engine commuter aircraft. Demonstrated cases include symmetrical revolutions of propellers for both identical and inverse directions of rotation, cases of single engine failure and single propeller feathering, and finally, cases of unsymmetrical revolutions including the reduced and increased revolutions of a single propeller, for both identical and inverse directions of rotation.

  19. Flutter performance of bend-twist coupled large-scale wind turbine blades

    Science.gov (United States)

    Hayat, Khazar; de Lecea, Alvaro Gorostidi Martinez; Moriones, Carlos Donazar; Ha, Sung Kyu

    2016-05-01

    The bend-twist coupling (BTC) is proven to be effective in mitigating the fatigue loads for large-scale wind turbine blades, but at the same time it may cause the risk of flutter instability. The BTC is defined as a feature of twisting of the blade induced by the primary bending deformation. In the classical flutter, the BTC arises from the aerodynamic loads changing with the angle of attack. In this study, the effects of the structural BTC on the flutter are investigated by considering the layup unbalances (ply angle, material and thickness of the composite laminates) in the NREL 5-MW wind turbine rotor blade of glass fiber/epoxy [02/+45/-45]S laminates. It is numerically shown that the flutter speed may decrease by about 5 percent with unbalanced ply-angle only (one side angle, from 45° to 25°). It was then demonstrated that the flutter performance of the wind turbine blade can be increased by using lighter and stiffer carbon fibers which ensures the higher structural BTC at the same time.

  20. Canadian Cardiovascular Society atrial fibrillation guidelines 2010: rate and rhythm management.

    Science.gov (United States)

    Gillis, Anne M; Verma, Atul; Talajic, Mario; Nattel, Stanley; Dorian, Paul

    2011-01-01

    The goals of atrial fibrillation (AF) and atrial flutter (AFL) arrhythmia management are to alleviate patient symptoms, improve patient quality of life, and minimize the morbidity associated with AF and AFL. Arrhythmia management usually commences with drugs to slow the ventricular rate. The addition of class I or class III antiarrhythmic drugs for restoration or maintenance of sinus rhythm is largely determined by patient symptoms and preferences. For rate control, treatment of persistent or permanent AF and AFL should aim for a resting heart rate of myocardial infarction or left ventricular dysfunction. Digoxin is not recommended as monotherapy for rate control in active patients. Digoxin and dronedarone may be used in combination with other agents to optimize rate control. The first-choice antiarrhythmic drug for maintenance of sinus rhythm in patients with non structural heart disease can be any one of dronedarone, flecainide, propafenone, or sotalol. In patients with abnormal ventricular function but left ventricular ejection fraction >35%, dronedarone, sotalol, or amiodarone is recommended. In patients with left ventricular ejection fraction <35%, amiodarone is the only drug usually recommended. Intermittent antiarrhythmic drug therapy ("pill in the pocket") may be considered in symptomatic patients with infrequent, longer-lasting episodes of AF or AFL as an alternative to daily antiarrhythmic therapy. Referral for ablation of AF may be considered for patients who remain symptomatic after adequate trials of antiarrhythmic drug therapy and in whom a rhythm control strategy remains desired. Copyright © 2011 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  1. Dronedarone: a new antiarrhythmic agent for the treatment of atrial fibrillation.

    Science.gov (United States)

    Garcia, Danielle; Cheng-Lai, Angela

    2009-01-01

    In the armamentarium for rhythm control, amiodarone has been a mainstay of therapy for the management of atrial fibrillation (AF). Although amiodarone has shown to be effective in maintaining sinus rhythm, it has many extracardiac adverse effects. Dronedarone, a benzofuran amiodarone derivative, is structurally modified to reduce toxicities often associated with chronic amiodarone therapy. With the addition of a methylsulfonyl group, dronedarone is less lipophilic, has lower tissue accumulation, and a much shorter serum half-life of 24 hours compared with amiodarone. Dronedarone is also designed without the iodine moieties that are responsible for thyroid dysfunctions associated with amiodarone. Similar to amiodarone, dronedarone exhibits electrophysiologic characteristics of all 4 Vaughan Williams classifications. Phase III clinical trials have shown dronedarone to be effective at reducing ventricular rate, reducing recurrence of AF, and reducing cardiovascular morbidity and mortality in patients with AF or atrial flutter (AFL). However, dronedarone was associated with increased mortality in one study that included patients with severe heart failure (HL) and left ventricular dysfunction. Overall, dronedarone appears to be well tolerated. The most common side effects are gastrointestinal in nature and include nausea, vomiting, and diarrhea. Because of its more favorable adverse effect profile, dronedarone is likely to be a useful addition to the therapeutic management of AF. However, further comparative studies with amiodarone are needed to define dronedarone's place in therapy more clearly.

  2. [The value of physical therapy with VRP 1-Desitin ("Flutter")].

    Science.gov (United States)

    Lindemann, H

    1992-12-01

    Preliminary examinations with an innovative device for physiotherapy, VRP 1-Desitin ("Flutter"), in patients suffering from chronic mucus retention and bronchial collapse gave encouraging results. Therefore, we tried to confirm these findings and to evaluate the use of this new physiotherapy. It is based on oscillations of air in the respiratory tract during expiration (rate about 2 to 32 Hertz) diminishing adhesiveness of bronchial mucus and bronchial collapse. Pressure and flow changing depend on the position of mouth-piece and effort of breathing. In order to establish the efficiency of the VRP 1 a comparing investigation was initiated. 20 patients with cystic fibrosis, aged 7 to 28 years, performed physiotherapy with VRP 1 and autogenic drainage (AD), respectively, in a randomized order one after another, each physiotherapy taking twenty minutes. The expectorated sputum was weighed by means of a precision balance. Mean values during VRP 1 treatment were 5.0 g (range 0 to 12.0 g), during AD 4.8 g (range 0 to 11.7 g). There was no statistical difference (p VRP 1 physiotherapy is as effective as AD with respect to sputum elimination. In opposite to other methods not requiring a helping person it is simple to teach and to learn. It may be performed by young children (> or = 3 years) and adults, also in combination with inhalation. Thus, VRP 1 appears to be a real enrichment in physiotherapy.

  3. Flutter Phenomenon in Flow Driven Energy Harvester-A Unified Theoretical Model for "Stiff" and "Flexible" Materials.

    Science.gov (United States)

    Chen, Yu; Mu, Xiaojing; Wang, Tao; Ren, Weiwei; Yang, Ya; Wang, Zhong Lin; Sun, Chengliang; Gu, Alex Yuandong

    2016-10-14

    Here, we report a stable and predictable aero-elastic motion in the flow-driven energy harvester, which is different from flapping and vortex-induced-vibration (VIV). A unified theoretical frame work that describes the flutter phenomenon observed in both "stiff" and "flexible" materials for flow driven energy harvester was presented in this work. We prove flutter in both types of materials is the results of the coupled effects of torsional and bending modes. Compared to "stiff" materials, which has a flow velocity-independent flutter frequency, flexible material presents a flutter frequency that almost linearly scales with the flow velocity. Specific to "flexible" materials, pre-stress modulates the frequency range in which flutter occurs. It is experimentally observed that a double-clamped "flexible" piezoelectric P(VDF-TrFE) thin belt, when driven into the flutter state, yields a 1,000 times increase in the output voltage compared to that of the non-fluttered state. At a fixed flow velocity, increase in pre-stress level of the P(VDF-TrFE) thin belt up-shifts the flutter frequency. In addition, this work allows the rational design of flexible piezoelectric devices, including flow-driven energy harvester, triboelectric energy harvester, and self-powered wireless flow speed sensor.

  4. Effects of flutter and PEP mask physiotherapy on symptoms and lung function in children with cystic fibrosis

    NARCIS (Netherlands)

    van Winden, C. M.; Visser, A.; Hop, W.; Sterk, P. J.; Beckers, S.; de Jongste, J. C.

    1998-01-01

    Recently, the flutter was introduced as a new device to improve sputum expectoration. Preliminary data suggested a significant improvement in expectoration and lung function during flutter treatment in patients with cystic fibrosis (CF). The aim of the present study was to compare the effects of the

  5. CT findings of atrial myxoma

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    -wave morphology distribution was seen between patients with early-onset, lone paroxysmal AF and age- and gender-matched healthy control subjects. This finding indicates that alterations in atrial electrophysiology are common in the early stage of the arrhythmia, and since it occurs in young patients without co...

  7. Atrial fibrillation and delayed gastric emptying.

    Directory of Open Access Journals (Sweden)

    Isadora C Botwinick

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

  8. Derivatives of a statically reduced stiffness matrix with respect to sizing variables. [for aircraft weight minimization with flutter constraints

    Science.gov (United States)

    Oconnell, R. F.; Hassig, H. J.; Radovcich, N. A.

    1976-01-01

    An expression is obtained for the first derivatives with respect to the sizing variables of a statically reduced stiffness matrix that is a nonlinear function of the sizing variables, where the unreduced stiffness matrix is a linear function of the sizing variables. An accepted procedure to reduce the number of degrees of freedom is to eliminate a number of nodal displacements from the degrees of freedom such that the accuracy of the flutter analysis is not significantly affected. In a typical optimization procedure with flutter constraints, the derivative of the stiffness matrix may be used in a form that contains the characteristic vector of the flutter matrix equation and the transpose of the characteristic vector of the adjoint flutter matrix equation corresponding to a particular solution of the flutter equation.

  9. Classical Flutter and Active Control of Wind Turbine Blade Based on Piezoelectric Actuation

    Directory of Open Access Journals (Sweden)

    Tingrui Liu

    2015-01-01

    Full Text Available The aim of this article is to analyze classical flutter and active control of single-cell thin-walled composite wind turbine blade beam based on piezoelectric actuation. Effects of piezoelectric actuation for classical flutter suppression on wind turbine blade beam subjected to combined transverse shear deformation, warping restraint effect, and secondary warping are investigated. The extended Hamilton’s principle is used to set up the equations of motion, and the Galerkin method is applied to reduce the aeroelastic coupled equations into a state-space form. Active control is developed to enhance the vibrational behavior and dynamic response to classical aerodynamic excitation and stabilize structures that might be damaged in the absence of control. Active optimal control scheme based on linear quadratic Gaussian (LQG controller is implemented. The research provides a way for rare study of classical flutter suppression and active control of wind turbine blade based on piezoelectric actuation.

  10. Flutter analysis of hybrid metal-composite low aspect ratio trapezoidal wings in supersonic flow

    Directory of Open Access Journals (Sweden)

    Shokrollahi Saeed

    2017-02-01

    Full Text Available An effective 3D supersonic Mach box approach in combination with non-classical hybrid metal-composite plate theory has been used to investigate flutter boundaries of trapezoidal low aspect ratio wings. The wing structure is composed of two main components including aluminum material (in-board section and laminated composite material (out-board section. A global Ritz method is used with simple polynomials being employed as the trial functions. The most important objective of the present research is to study the effect of composite to metal proportion of hybrid wing structure on flutter boundaries in low supersonic regime. In addition, the effect of some important geometrical parameters such as sweep angle, taper ratio and aspect ratio on flutter boundaries were studied. The results obtained by present approach for special cases like pure metallic wings and results for high supersonic regime based on piston theory show a good agreement with those obtained by other investigators.

  11. Mathematical model and stability analysis of fluttering and autorotation of an articulated plate into a flow

    Science.gov (United States)

    Rostami, Ali Bakhshandeh; Fernandes, Antonio Carlos

    2018-03-01

    This paper is dedicated to develop a mathematical model that can simulate nonlinear phenomena of a hinged plate which places into the fluid flow (1 DOF). These phenomena are fluttering (oscillation motion), autorotation (continuous rotation) and chaotic motion (combination of fluttering and autorotation). Two mathematical models are developed for 1 DOF problem using two eminent mathematical models which had been proposed for falling plates (3 DOF). The procedures of developing these models are elaborated and then these results are compared to experimental data. The best model in the simulation of the phenomena is chosen for stability and bifurcation analysis. Based on these analyses, this model shows a transcritical bifurcation and as a result, the stability diagram and threshold are presented. Moreover, an analytical expression is given for finding the boundary of bifurcation from the fluttering to the autorotation.

  12. The effect of steady aerodynamic loading on the flutter stability of turbomachinery blading

    Science.gov (United States)

    Smith, Todd E.; Kadambi, Jaikrishnan R.

    1991-01-01

    An aeroelastic analysis is presented which accounts for the effect of steady aerodynamic loading on the aeroelastic stability of a cascade of compressor blades. The aeroelastic model is a two degree of freedom model having bending and torsional displacements. A linearized unsteady potential flow theory is used to determine the unsteady aerodynamic response coefficients for the aeroelastic analysis. The steady aerodynamic loading was caused by the addition of airfoil thickness and camber and steady flow incidence. The importance of steady loading on the airfoil unsteady pressure distribution is demonstrated. Additionally, the effect of steady loading on the tuned flutter behavior and flutter boundaries indicates that neglecting either airfoil thickness, camber or incidence could result in nonconservative estimates of flutter behavior.

  13. Atrial remodeling and atrial fibrillation: recent advances and translational perspectives.

    Science.gov (United States)

    Nattel, Stanley; Harada, Masahide

    2014-06-10

    Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice. AF and its complications are responsible for important population morbidity and mortality. Presently available therapeutic approaches have limited efficacy and nontrivial potential to cause adverse effects. Thus, new mechanistic knowledge is essential for therapeutic innovation. Atrial arrhythmogenic remodeling, defined as any change in atrial structure or function that promotes atrial arrhythmias, is central to AF. Remodeling can be due to underlying cardiac conditions, systemic processes and conditions such as aging, or AF itself. Recent work has underlined the importance of remodeling in AF, provided new insights into basic mechanisms, and identified new biomarker/imaging approaches to follow remodeling processes. The importance of intracellular Ca(2+) handling abnormalities has been highlighted, both for the induction of triggered ectopic activity and for the activation of Ca(2+)-related cell signaling that mediates profibrillatory remodeling. The importance of microRNAs, which are a new class of small noncoding sequences that regulate gene expression, has emerged in both electrical and structural remodeling. Remodeling related to aging, cardiac disease, and AF itself is believed to underlie the progressive nature of the arrhythmia, which contributes to the complexities of long-term management. New tools that are being developed to quantify remodeling processes and monitor their progression include novel biomarkers, imaging modalities to quantify/localize fibrosis, and noninvasive monitoring/mapping to better characterize the burden of AF and identify arrhythmic sources. This report reviews recent advances in the understanding of the basic pathophysiology of atrial remodeling and potential therapeutic implications. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  14. Comparison of Flutter device and chest physical therapy in the treatment of cystic fibrosis pulmonary exacerbation.

    Science.gov (United States)

    Gondor, M; Nixon, P A; Mutich, R; Rebovich, P; Orenstein, D M

    1999-10-01

    Chest physiotherapy (CPT) is recommended for the clearance of bronchial secretions in the management of patients with cystic fibrosis (CF). The Flutter valve (Scandipharm, Birmingham, AL) has been introduced as an alternative method to CPT for airway mucus clearance. The objective of this study was to compare the short-term effects of CPT and the Flutter valve on pulmonary function and exercise tolerance in patients with cystic fibrosis. Twenty-three patients, 5 to 21 years of age, were randomized to receive one of two interventions: CPT or the Flutter valve, upon admission to the hospital for a 2-week treatment of pulmonary exacerbation. Pulmonary function testing (PFTs) and the 6-min walk test were performed on admission, day 7, and day 14 of hospitalization. Data analysis indicated no significant differences between the two groups on admission. Both groups showed improvement in pulmonary function test results, but the Flutter group had a higher mean forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV(1)) compared to the CPT group after 1 week of intervention. Both groups continued to improve during the 2-week intervention, with no significant difference in FVC or FEV(1) between groups by the end of 2 weeks. Mean forced expiratory flow rate between 25-75% of vital capacity (FEF(25-75)), 6-min walk distance, and resting arterial oxyhemoglobin saturation (SaO(2)) showed little change by day 7, but improved significantly (P< 0.05) by day 14 of hospitalization in both groups, with no significant difference between groups. This study demonstrated that patients using the Flutter device had better pulmonary function after 1 week of therapy and similar improvement in pulmonary function and exercise tolerance compared to CPT after 2 weeks of therapy, suggesting that Flutter valve therapy is an acceptable alternative to standard CPT during in-hospital care of patients with CF. Copyright 1999 Wiley-Liss, Inc.

  15. Flutter valve improves respiratory mechanics and sputum production in patients with bronchiectasis.

    Science.gov (United States)

    Figueiredo, Pedro H S; Zin, Walter A; Guimarães, Fernando S

    2012-03-01

    Although the application of airway clearance techniques is considered an important component in the treatment of several obstructive pulmonary diseases, there is no scientific evidence supporting the use of Flutter Valve™ in the management of patients with bronchiectasis. Moreover, the consequences of respiratory physiotherapy techniques on respiratory mechanics have not been fully studied. Therefore, we investigated the acute, short-term effects of Flutter Valve™ on respiratory mechanics and sputum production in bronchiectatic patients.  EIGHT patients were evaluated in a randomized, blinded, cross-over trial. Impedance at 5 Hz (R5), resistance as a function of oscillation frequency (dR/dF), reactance at 5 Hz (X5), resonant frequency (f(0) ) and integral of reactance between 5 Hz and resonant frequency (AX) were recorded.  Flutter Valve™ cleared 8.4 mL more secretions than the Sham Flutter intervention (95% confidence interval [95% CI], 3.4-13.4). There was a higher percentage decrease in R5 (-11.2%; 95% CI, -4.4 to -18.2), dR/dF (-20.8%; 95% CI, -32.4 to -9) and AX (-7.8%; 95% CI, -11.9 to -3.7) under Flutter Valve™. X5 and f(0) variation did not differ between interventions.   Flutter Valve™ increases sputum removal during treatment and diminishes total and peripheral airway resistance in hypersecretive patients with bronchiectasis. Impulse oscillometry is a user-friendly tool to evaluate the effects of airway clearance techniques on respiratory mechanics. Copyright © 2010 John Wiley & Sons, Ltd.

  16. Personalized management of atrial fibrillation

    DEFF Research Database (Denmark)

    Kirchhof, Paulus; Breithardt, Günter; Aliot, Etienne

    2013-01-01

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

  17. Right Atrial Myxoma and Syncope.

    Science.gov (United States)

    Babs Animashaun, Islamiyat; Akinseye, Oluwaseun A; Akinseye, Leah I; Akinboboye, Olakunle O

    2015-09-21

    Right atrial myxoma accounts for 15-20% of cardiac myxomas and syncope is a very rare manifestation. We present the case of an 89-year-old man with right atrial myxoma and syncope, and discuss the role of cardiac magnetic resonance imaging (MRI) in the diagnosis of myxomas. An 89-year-old man with a history of hypertension, hyperlipidemia, chronic kidney disease stage 4, mild dementia, and benign prostatic hyperplasia presented to the emergency department with an episode of syncope. Physical examination demonstrated normal and regular heart sounds, and normal respiratory rate and oxygen saturation. Echocardiogram described a well-circumscribed echo-dense mass in the right atrial cavity, which was attached to the septum but not obstructing the tricuspid annulus, measuring 1.7×2.2 cm at its widest diameter. Cardiac MRI revealed a mass with dark intensity which enhanced heterogeneously following intravenous administration of gadolinium-chelate, consistent with a myxoma. The location of this myxoma, coupled with the presence of a stalk allowing mobility, provides a clue to how this patient experienced transient obstruction of the tricuspid valve leading to syncope. Right heart tumors should be considered in the differential diagnosis of unexplained syncope. Cardiac MRI with gadolinium-chelate administration can help differentiate this tumor from a right-sided atrial thrombus, which can pose a diagnostic challenge.

  18. Genetic aspects of atrial fibrillation

    NARCIS (Netherlands)

    Wiesfeld, ACP; Hemels, MEW; Van Tintelen, JP; Van den Berg, MP; Van Veldhuisen, DJ; Van Gelder, IC

    2005-01-01

    Atrial fibrillation (AF) occurs predominantly in the elderly and is commonly associated with underlying cardiac diseases. A significant number of patients, however, have early onset AF that is not associated with any underlying disease. At present, it is unknown how often this form of AF is familial

  19. Deglutition-Induced Atrial Fibrillation

    Science.gov (United States)

    Malik, Amyn; Ali, Syed Sohail; Rahmatullah, Amin

    2005-01-01

    We present the case of 38-year-old woman who experienced palpitations on swallowing, which were later found to be atrial fibrillation. Her symptoms improved on treatment with disopyramide and verapamil. Within 9 months, she was weaned from both medications without recurrence of symptoms. PMID:16429915

  20. Uncertainty Quantification of the FUN3D-Predicted NASA CRM Flutter Boundary

    Science.gov (United States)

    Stanford, Bret K.; Massey, Steven J.

    2017-01-01

    A nonintrusive point collocation method is used to propagate parametric uncertainties of the flexible Common Research Model, a generic transport configuration, through the unsteady aeroelastic CFD solver FUN3D. A range of random input variables are considered, including atmospheric flow variables, structural variables, and inertial (lumped mass) variables. UQ results are explored for a range of output metrics (with a focus on dynamic flutter stability), for both subsonic and transonic Mach numbers, for two different CFD mesh refinements. A particular focus is placed on computing failure probabilities: the probability that the wing will flutter within the flight envelope.

  1. Uso da radiofrequência bipolar para o tratamento da fibrilação atrial durante cirurgia cardíaca Uso de la radiofrecuencia bipolar para el tratamiento de la fibrilación atrial durante cirugía cardíaca Use of bipolar radiofrequency for the treatment of atrial fibrillation during cardiac surgery

    Directory of Open Access Journals (Sweden)

    Leonardo Secchin Canale

    2011-06-01

    Full Text Available FUNDAMENTO: O tratamento da fibrilação atrial com dispositivo de ablação de tecidos por radiofrequência bipolar em concomitância à cirurgia cardíaca tem se mostrado método eficaz no tratamento desta arritmia. OBJETIVO: Descrever a experiência inicial do Instituto Nacional de Cardiologia no tratamento cirúrgico da fibrilação atrial com uso de dispositivo de radiofrequência bipolar em pacientes submetidos à cirurgia cardíaca, relatando o resultado de acompanhamento pós-operatório de um ano. MÉTODOS: Entre janeiro de 2008 e março de 2009, 47 pacientes (36 mulheres consecutivos, com idade média de 53,7 ± 10,6 anos, apresentando fibrilação atrial por um período médio de 34,6 meses (3 a 192 meses foram submetidos à ablação cirúrgica desta arritmia, por radiofrequência bipolar, durante o procedimento que motivou a indicação da cirurgia. Oito apresentavam fibrilação atrial intermitente e 39, contínua. Oitenta e um por cento foram submetidos à cirurgia valvar como procedimento principal. Esta é uma análise retrospectiva, observacional, com avaliação de um ano de pós-operatório das variáveis clínicas e de Holter 24 h. RESULTADOS: Dos 47 pacientes, 40 sobreviveram um ano. Desses, 33 foram submetidos a Holter 24 h, em um intervalo médio de 401 dias após a cirurgia. Encontrou-se a seguinte distribuição de ritmos: 24 (73% sinusal, 5 (15% fibrilação atrial, três (9% Flutter atrial e um (3% ritmo juncional. Foram observados dois acidentes vasculares encefálicos, sendo um associado à arritmia supraventricular. CONCLUSÃO: A ablação cirúrgica de fibrilação atrial com dispositivo de radiofrequência bipolar concomitante à cirurgia cardíaca é método eficaz para o tratamento desta arritmia.FUNDAMENTO: El tratamiento de la fibrilación atrial con dispositivo de ablación de tejidos por radiofrecuencia bipolar en concomitancia con la cirugía cardíaca se muestra un método eficaz en el tratamiento de esta

  2. Atrial Fibrillation and Colonic Neoplasia in African Americans.

    Directory of Open Access Journals (Sweden)

    Mehdi Nouraie

    Full Text Available Colorectal cancer (CRC and atrial fibrillation/flutter (AF share several risk factors including increasing age and obesity. However, the association between CRC and AF has not been thoroughly examined, especially in African Americans. In this study we aimed to assess the prevalence of AF and its risk factors in colorectal neoplasia in an African American.We reviewed records of 527 African American patients diagnosed with CRC and 1008 patients diagnosed with benign colonic lesions at Howard University Hospital from January 2000 to December 2012. A control group of 731 hospitalized patients without any cancer or colonic lesion were randomly selected from the same time and age range, excluding patients who had diagnosis of both CRC and/or adenoma. The presence or absence of AF was based upon ICD-9 code documentation. The prevalence of AF in these three groups was compared by multivariate logistic regression.The prevalence of AF was highest among CRC patients (10% followed by adenoma patients (7.2% then the control group (5.4%, P for trend = 0.002. In the three groups of participants, older age (P<0.008 and heart failure (P<0.001 were significantly associated with higher risk of AF. After adjusting for these risk factors, CRC (OR: 1.4(95%CI:0.9-2.2, P = 0.2 and adenoma (OR: 1.1(95%CI:0.7-1.6, P = 0.7 were not significantly associated AF compared to control group.AF is highly prevalent among CRC patients; 1 in 10 patients had AF in our study. The predictors of AF in CRC was similar to that in adenoma and other patients after adjustment for potential confounders suggesting that the increased AF risk in CRC is explained by higher prevalence of AF risk factors.

  3. Atrial Fibrillation and Colonic Neoplasia in African Americans.

    Science.gov (United States)

    Nouraie, Mehdi; Kansal, Vandana; Belfonte, Cassius; Ghazvini, Mohammad; Haidari, Tahmineh; Shahnazi, Anahita; Brim, Hassan; Soliman, Elsayed Z; Ashktorab, Hassan

    2015-01-01

    Colorectal cancer (CRC) and atrial fibrillation/flutter (AF) share several risk factors including increasing age and obesity. However, the association between CRC and AF has not been thoroughly examined, especially in African Americans. In this study we aimed to assess the prevalence of AF and its risk factors in colorectal neoplasia in an African American. We reviewed records of 527 African American patients diagnosed with CRC and 1008 patients diagnosed with benign colonic lesions at Howard University Hospital from January 2000 to December 2012. A control group of 731 hospitalized patients without any cancer or colonic lesion were randomly selected from the same time and age range, excluding patients who had diagnosis of both CRC and/or adenoma. The presence or absence of AF was based upon ICD-9 code documentation. The prevalence of AF in these three groups was compared by multivariate logistic regression. The prevalence of AF was highest among CRC patients (10%) followed by adenoma patients (7.2%) then the control group (5.4%, P for trend = 0.002). In the three groups of participants, older age (PCRC (OR: 1.4(95%CI):0.9-2.2, P = 0.2) and adenoma (OR: 1.1(95%CI):0.7-1.6, P = 0.7) were not significantly associated AF compared to control group. AF is highly prevalent among CRC patients; 1 in 10 patients had AF in our study. The predictors of AF in CRC was similar to that in adenoma and other patients after adjustment for potential confounders suggesting that the increased AF risk in CRC is explained by higher prevalence of AF risk factors.

  4. Rhythm- and rate-controlling effects of dronedarone in patients with atrial fibrillation (from the ATHENA trial).

    Science.gov (United States)

    Page, Richard L; Connolly, Stuart J; Crijns, Harry J G M; van Eickels, Martin; Gaudin, Christophe; Torp-Pedersen, Christian; Hohnloser, Stefan H

    2011-04-01

    Dronedarone is a multi-channel-blocking drug for the treatment of patients with atrial fibrillation (AF) or atrial flutter (AFL) with rate- and rhythm-controlling properties. A Placebo-Controlled, Double-Blind, Parallel Arm Trial to Assess the Efficacy of Dronedarone 400 mg b.i.d. for the Prevention of Cardiovascular Hospitalization or Death from Any Cause in Patients With Atrial Fibrillation/Atrial Flutter (ATHENA) demonstrated that dronedarone reduced the risk for first cardiovascular hospitalization or death from any cause. The aim of this post hoc analysis was to evaluate the rhythm- and rate-controlling properties of dronedarone in the ATHENA trial. Patients were randomized to dronedarone 400 mg twice daily (n = 2,301) or placebo (n = 2,327). Electrocardiographic tracings were classified for AF or AFL or sinus rhythm. Patients with AF or AFL on every postbaseline electrocardiogram were classified as having permanent AF or AFL. All electrical cardioversions were documented. The use of rate-controlling medications was equally distributed in the 2 treatment groups. The median time to first AF or AFL recurrence of patients in sinus rhythm at baseline was 498 days in placebo patients and 737 days in dronedarone patients (hazard ratio 0.749, 95% confidence interval 0.681 to 0.824, p <0.001). In the dronedarone group, 339 patients (15%) had ≥1 electrical cardioversion, compared to 481 (21%) in the placebo group (hazard ratio 0.684, 95% confidence interval 0.596 to 0.786, p <0.001). The likelihood of permanent AF or AFL was lower with dronedarone (178 patients [7.6%]) compared to placebo (295 patients [12.8%]) (p <0.001). At the time of first AF or AFL recurrence, the mean heart rates were 85.3 and 95.5 beats/min in the dronedarone and placebo groups, respectively (p <0.001). In conclusion, dronedarone demonstrated both rhythm- and rate-controlling properties in ATHENA. These effects are likely to contribute to the reduction of important clinical outcomes observed

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

    DEFF Research Database (Denmark)

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

    2005-01-01

    Objective To investigate the safety and efficacy of Left atrial linear ablation of paroxysmal atrial fibrillation guided by three-dimensional electroanatomical system. Methods 29 patients with paroxysmal atrial fibrillation in this study. A nonfluoroscopic mapping system was used to generate a 3D......±15. After a follow-up of 6.0 months, 24 patients maintained sinus rhythm. 3 patients suffered from less frequent paroxysmal atrial fibrillation during the first 3.0 months after the ablation and remained Af free after 6 months. I patient had atrial fibrillation episodes and I patient had atrial fibrillation...... attacks unchanged. No pulmonary vein narrowing was observed. Conclusion Left atrial linear ablation of paroxysmal atrial fibrillation guided by three-dimensional electroanatomical system was safe and effective....

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

    NARCIS (Netherlands)

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

    1998-01-01

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

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

    NARCIS (Netherlands)

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

    1998-01-01

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

  8. Staged hybrid ablation for persistent and longstanding persistent atrial fibrillation effectively restores sinus rhythm in long-term observation.

    Science.gov (United States)

    Zembala, Michal; Filipiak, Krzysztof; Kowalski, Oskar; Buchta, Piotr; Niklewski, Tomasz; Nadziakiewicz, Pawel; Koba, Rafał; Gąsior, Mariusz; Kalarus, Zbigniew; Zembala, Marian

    2017-02-01

    Hybrid ablation (HABL) of atrial fibrillation combining endoscopic, minimally invasive, closed chest epicardial ablation with endocardial CARTO-guided accuracy was introduced to overcome the limitations of current therapeutic options for patients with persistent (PSAF) and longstanding persistent atrial fibrillation (LSPAF). The purpose of this study was to evaluate the procedural safety and feasibility as well as effectiveness of HABL in patients with PSAF and LSPAF 1 year after the procedure. The study is a single-center, prospective clinical registry. From 07/2009 to 12.2014, 90 patients with PSAF (n = 39) and LSPAF (n = 51), at the mean age of 54.8 ±9.8, in mean EHRA class 2.6, underwent HABL. 64.4% of patients had a history of prior cardioversion or catheter ablation. Thirteen patients had LVEF less than 35%. Mean AF duration was 4.5 ±3.7 years. Patients were scheduled for 3-, 6- and 12-month follow-up with 7-day Holter monitoring. At 6 months after the procedure 78% (54/69) of patients were in SR. At 12 months after the procedure 86% (59/69) were in SR and 62.3% (43/69) in SR and off class I/III antiarrhythmic drugs (AADs). Only 1% (1/69) of patients required a repeat ablation for atrial flutter. A significant decrease in LA dimension and an increase in LVEF were noted. A combination of epicardial and endocardial RF ablation should be considered as a treatment option for patients with persistent and long-standing persistent atrial fibrillation as it is safe and effective in restoring sinus rhythm.

  9. Age and Phonetic Influences on Velar Flutter as a Component of Nasal Turbulence in Children With Repaired Cleft Palate.

    Science.gov (United States)

    Zajac, David J; Preisser, John

    2016-11-01

      The purpose of this study was to determine the influence of age and selected phonetic factors on velar flutter as a component of nasal turbulence in children with repaired cleft palate.   A total of 30 children with repaired cleft palate with or without cleft lip ranging in age from 4 to 13 years (mean, 8.6 years; standard deviation, 2.4 years) who exhibited nasal turbulence characterized by velar flutter participated in the study.   The headset of a nasometer was used to record the children producing multiple repetitions of consonant-vowel (CV) syllables that contrasted the stops /p/ and /t/ with the fricatives /f/ and /s/ and the high-front vowel /i/ with the low mid-central vowel /Λ/. All targeted consonants were coded relative to the presence of flutter using both perceptual and spectral criteria. Percentages of syllables coded for flutter were calculated as a function of consonant and vowel types. Intra-and interjudge reliability of coding was high.   Percentages of syllables with velar flutter ranged from a high of 100% to a low of 4% among the participants. A Spearman rank-order correlation between age and percentage of syllables with flutter was nonsignificant. Mantel-Haenszel tests for repeated measures indicated that flutter occurred more often during production of syllables containing /i/ (62%) when compared with /Λ/ (50%) (P = .029).   Velar flutter as a component of nasal turbulence varies widely among children with repaired cleft palate. CV syllables with high vowels appear to trigger velar flutter more often than syllables with low vowels.

  10. Probabilistic Design of a Plate-Like Wing to Meet Flutter and Strength Requirements

    Science.gov (United States)

    Stroud, W. Jefferson; Krishnamurthy, T.; Mason, Brian H.; Smith, Steven A.; Naser, Ahmad S.

    2002-01-01

    An approach is presented for carrying out reliability-based design of a metallic, plate-like wing to meet strength and flutter requirements that are given in terms of risk/reliability. The design problem is to determine the thickness distribution such that wing weight is a minimum and the probability of failure is less than a specified value. Failure is assumed to occur if either the flutter speed is less than a specified allowable or the stress caused by a pressure loading is greater than a specified allowable. Four uncertain quantities are considered: wing thickness, calculated flutter speed, allowable stress, and magnitude of a uniform pressure load. The reliability-based design optimization approach described herein starts with a design obtained using conventional deterministic design optimization with margins on the allowables. Reliability is calculated using Monte Carlo simulation with response surfaces that provide values of stresses and flutter speed. During the reliability-based design optimization, the response surfaces and move limits are coordinated to ensure accuracy of the response surfaces. Studies carried out in the paper show the relationship between reliability and weight and indicate that, for the design problem considered, increases in reliability can be obtained with modest increases in weight.

  11. Flutter Analysis of the Thermal Protection Layer on the NASA HIAD

    Science.gov (United States)

    Goldman, Benjamin D.; Dowell, Earl H.; Scott, Robert C.

    2013-01-01

    A combination of classical plate theory and a supersonic aerodynamic model is used to study the aeroelastic flutter behavior of a proposed thermal protection system (TPS) for the NASA HIAD. The analysis pertains to the rectangular configurations currently being tested in a NASA wind-tunnel facility, and may explain why oscillations of the articles could be observed. An analysis using a linear flat plate model indicated that flutter was possible well within the supersonic flow regime of the wind tunnel tests. A more complex nonlinear analysis of the TPS, taking into account any material curvature present due to the restraint system or substructure, indicated that significantly greater aerodynamic forcing is required for the onset of flutter. Chaotic and periodic limit cycle oscillations (LCOs) of the TPS are possible depending on how the curvature is imposed. When the pressure from the base substructure on the bottom of the TPS is used as the source of curvature, the flutter boundary increases rapidly and chaotic behavior is eliminated.

  12. Critical and post-critical behaviour of two-degree-of-freedom flutter-based generators

    Science.gov (United States)

    Pigolotti, Luca; Mannini, Claudio; Bartoli, Gianni; Thiele, Klaus

    2017-09-01

    Energy harvesting from flow-induced vibrations is a recent research field, which considers a diverse range of systems, among which two-degree-of-freedom flutter-based solutions were individuated as good candidates to obtain high energy performance. In the present work, numerical linear analyses and wind-tunnel tests were conducted on a flat-plate sectional model. The aim is to identify some design guidelines for generators exploiting the classical-flutter instability, through the investigation of the critical condition and the response during the post-critical regime. Many sets of governing parameters of interest from the energy-harvesting point of view were considered, including high levels of heaving damping to simulate the operation of a conversion apparatus. In particular, eccentricity of the elastic centre and small downstream mass unbalance can be introduced as solutions aiming at optimal operative ranges. The collected results suggest the high potentiality of flutter-based generators, and a significant enhancement of performance can be envisaged. Moreover, they contribute to improve the knowledge of the flutter excitation mechanism and to widen the dataset of measurements in the post-critical regime.

  13. Nonlinear flutter wind tunnel test and numerical analysis of folding fins with freeplay nonlinearities

    Directory of Open Access Journals (Sweden)

    Yang Ning

    2016-02-01

    Full Text Available The flutter characteristics of folding control fins with freeplay are investigated by numerical simulation and flutter wind tunnel tests. Based on the characteristics of the structures, fins with different freeplay angles are designed. For a 0° angle of attack, wind tunnel tests of these fins are conducted, and vibration is observed by accelerometers and a high-speed camera. By the expansion of the connected relationships, the governing equations of fit for the nonlinear aeroelastic analysis are established by the free-interface component mode synthesis method. Based on the results of the wind tunnel tests, the flutter characteristics of fins with different freeplay angles are analyzed. The results show that the vibration divergent speed is increased, and the divergent speed is higher than the flutter speed of the nominal linear system. The vibration divergent speed is increased along with an increase in the freeplay angle. The developed free-interface component mode synthesis method could be used to establish governing equations and to analyze the characteristics of nonlinear aeroelastic systems. The results of the numerical simulations and the wind tunnel tests indicate the same trends and critical velocities.

  14. Effect of blade flutter and electrical loading on small wind turbine noise

    Science.gov (United States)

    The effect of blade flutter and electrical loading on the noise level of two different size wind turbines was investigated at the Conservation and Production Research Laboratory (CPRL) near Bushland, TX. Noise and performance data were collected on two blade designs tested on a wind turbine rated a...

  15. Congenital left atrial appendage aneurysm: Atypical presentation

    Directory of Open Access Journals (Sweden)

    Mehdi Bamous

    2017-01-01

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

  16. Atrial Fibrillation after Robotic Cardiac Surgery

    OpenAIRE

    LEONARDO CANALE; STEPHANIE MICK; RAVI NAIR; TOMISLAV MIHALJEVIC; JOHANNES BONATTI

    2014-01-01

    Atrial fibrillation is a common arrhythmia after conventional open heart surgery. A minimally invasive robotic approach has the potential to lower its occurrence. We sought to review the literature on the incidence of post operative atrial fibrillation in robotic heart surgery and compare it to the incidence in conventional cardiac surgery. The types of operation investigated were: coronary artery bypass surgery, mitral valve repair, atrial septal defect closure and myxoma excision. Operation...

  17. Magnetic Flutter Plasma Transport Induced by 3D Fields in DIII-D

    Science.gov (United States)

    Smith, S. P.

    2013-10-01

    New combined MHD and transport modeling show that the recently developed magnetic flutter model of plasma transport predicts an electron thermal diffusivity ``hill'' at the top of the pedestal comparable to that seen in DIII-D discharges where edge localized modes (ELMs) are suppressed by the application of 3D fields. It is hypothesized that this ``hill'' prevents the inward growth of the pedestal to avoid reaching the peeling-ballooning limit that precipitates an ELM. The magnetic perturbations in the plasma are modeled with the two fluid MHD M3D-C1 code, which results in perturbation harmonics that are flow-screened or amplified (relative to vacuum calculations) at their corresponding rational surface. Despite any screening, the flutter predicted diffusivity peaks at the rational surfaces in the plasma. However, in integrating the inverse of the diffusivity to obtain an electron temperature profile, the average predicted temperature gradient is dominated by the smaller but finite diffusivity between rational surfaces. The magnitude of the flutter predicted diffusivity is decreased by a factor of about 4/13 when the effects of the pressure gradient and radial electric field (off-diagonal transport matrix terms) are taken into account, and this lower predicted diffusivity is much closer to the experimentally inferred diffusivity. On the other hand, adding a large diffusivity in the approximate island width regions around the rational surfaces leads to a diffusivity much higher than inferred experimentally. Flutter effects on the electric field and particle transport are also currently being investigated. These flutter model studies provide a promising new approach for developing a predictive capability for achieving ELM suppression in future devices. Supported by the US DOE under DE-FC02-04ER54698.

  18. Start or STop Anticoagulants Randomised Trial (SoSTART)

    Science.gov (United States)

    2017-10-25

    Intracranial Hemorrhages; Intracranial Hemorrhage, Hypertensive; Subarachnoid Hemorrhage; Subdural Hematoma; Intraventricular Hemorrhage; Atrial Fibrillation; Atrial Flutter; Small Vessel Cerebrovascular Disease; Microhaemorrhage

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

    African Journals Online (AJOL)

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

  20. A new system for right atrial cooling

    NARCIS (Netherlands)

    Huybregts, Marinus A. J. M.; de Vroege, Roel; van Oeveren, Wim

    Purpose. Controlled hypothermia of the right atrium has been shown to reduce postoperative atrial fibrillation after on-pump coronary artery bypass grafting. A device has been developed that couples right atrial and nodal cooling with modified dual-stage venous drainage by circulating cold sterile

  1. Atrial fibrillation in patients with ischemic stroke

    DEFF Research Database (Denmark)

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

    2009-01-01

    BACKGROUND: Atrial fibrillation is a major risk factor for ischemic stroke. However, the prognostic impact of atrial fibrillation among patients with stroke is not fully clarified. We compared patient characteristics, including severity of stroke and comorbidity, quality of in-hospital care and o...

  2. Genetics Home Reference: familial atrial fibrillation

    Science.gov (United States)

    ... to be associated with familial atrial fibrillation was KCNQ1 , which provides instructions for making a channel that ... atrial fibrillation ABCC9 GJA5 KCNA5 KCNE2 KCNH2 KCNJ2 KCNQ1 LMNA MYL4 NKX2-5 NPPA NUP155 PRKAG2 RYR2 ...

  3. Blocked atrial bigeminy presenting with bradycardia.

    Science.gov (United States)

    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. © 2012 Wiley Periodicals, Inc.

  4. Evaluation of optimal treatment approach in patients with early recurrence of atrial fibrillation after the first ablation procedure

    Directory of Open Access Journals (Sweden)

    В. В. Шабанов

    2015-10-01

    Full Text Available 182 patients with paroxysmal AF underwent ablation (circumferential pulmonary vein isolation with linear lesions and were monitored with an implantable cardiac monitor (Reveal XT, Medtronic. Patients were randomly assigned to group 1 or group 2. Group 1 patients were treated only with antiarrhythmic drugs for 6 weeks, with no early reablation during the 3-month postablation period. In the case of AF recurrence after the 3-month postablation period, patients underwent reablation. Group 2 patients were treated according to the onset mechanism of AF recurrences, as detected and stored by the implantable cardiac monitor: antiarrhythmic drug therapy, but no reablation if AF was not preceded by triggers; early reablation if premature atrial beats or atrial tachycardias or flutter triggered AF. All patients were followed up for 1 year to assess the sinus rhythm maintenance in each group. On 12-month follow-up examination, 67 patients (76% out of 88 in group 1 and 78 patients (92% out of 89 in group 2 had no AF recurrences (P<0,009 versus group 1. The patients with AF recurrences caused by a trigger mechanism after the first ablation demonstrated high long-term efficacy after early reablation.

  5. Postoperative atrial fibrillation in patients with left atrial myxoma.

    Science.gov (United States)

    Sahin, Muslum; Tigen, Kursat; Dundar, Cihan; Ozben, Beste; Alici, Gokhan; Demir, Serdar; Kalkan, Mehmet Emin; Ozkan, Birol

    2015-01-01

    The aim of this study was to determine the factors associated with postoperative atrial fibrillation (AF) in patients with left atrial (LA) myxoma. Thirty-six consecutive patients with LA myxoma (10 men, mean age: 49.3 ± 15.7 years), who were operated on between March 2010 and July 2012, were included in this retrospective study. Pre-operative electrocardiograms and echocardiographic examinations of each patient were reviewed. Postoperative AF developed in 10 patients, whereas there was no evidence of paroxysmal AF after resection of the LA myxoma in the remaining 26 patients. The patients who developed AF postoperatively were significantly older than those who did not develop AF (median: 61.5 vs 46 years; p = 0.009). Among the electrocardiographic parameters, only P-wave dispersion differed significantly between postoperative AF and non-AF patients (median: 57.6 vs 39.8 ms, p = 0.004). Logistic regression analysis revealed P- wave dispersion (OR: 1.11, 95% CI: 1.003-1.224, p = 0.043) and age (OR: 1.13, 95% CI: 1.001-1.278, p = 0.048) as independent predictors of postoperative AF in our cohort of patients. P-wave dispersion is a simple and useful parameter for the prediction of postoperative AF in patients with LA myxoma.

  6. Cetirizine-Induced atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Altuğ Osken

    2016-01-01

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

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

    DEFF Research Database (Denmark)

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

    2005-01-01

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

  8. Nonlinear panel flutter in a rarefied atmosphere - Aerodynamic shear stress effects

    Science.gov (United States)

    Resende, Hugo B.

    1991-01-01

    The panel flutter phenomenon is studied assuming free-molecule flow. This kind of analysis is relevant in the case of hypersonic flight vehicles traveling at high altitudes, especially in the leeward portion of the vehicle. In these conditions the aerodynamic shear can be expected to be considerably larger than the pressure at a given point, so that the effects of such a loading are incorporated into the structural model. This is accomplished by introducing distributed longitudinal and bending moment loads. The former can lead to buckling of the panel, with the second mode in the case of a simply-supported panel playing a important role, and becoming the dominant mode in the solution. The presence of equivalent springs in the longitudinal direction at the panel's ends also becomes of relative importance, even for the evaluation of the linear flutter parameter. Finally, the behavior of the system is studied in the presence of applied compressive forces, that is, classical buckling.

  9. Design and experiment of data-driven modeling and flutter control of a prototype wing

    Science.gov (United States)

    Lum, Kai-Yew; Xu, Cai-Lin; Lu, Zhenbo; Lai, Kwok-Leung; Cui, Yongdong

    2017-06-01

    This paper presents an approach for data-driven modeling of aeroelasticity and its application to flutter control design of a wind-tunnel wing model. Modeling is centered on system identification of unsteady aerodynamic loads using computational fluid dynamics data, and adopts a nonlinear multivariable extension of the Hammerstein-Wiener system. The formulation is in modal coordinates of the elastic structure, and yields a reduced-order model of the aeroelastic feedback loop that is parametrized by airspeed. Flutter suppression is thus cast as a robust stabilization problem over uncertain airspeed, for which a low-order H∞ controller is computed. The paper discusses in detail parameter sensitivity and observability of the model, the former to justify the chosen model structure, and the latter to provide a criterion for physical sensor placement. Wind tunnel experiments confirm the validity of the modeling approach and the effectiveness of the control design.

  10. Flutter analysis of an airfoil with nonlinear damping using equivalent linearization

    Directory of Open Access Journals (Sweden)

    Chen Feixin

    2014-02-01

    Full Text Available The equivalent linearization method (ELM is modified to investigate the nonlinear flutter system of an airfoil with a cubic damping. After obtaining the linearization quantity of the cubic nonlinearity by the ELM, an equivalent system can be deduced and then investigated by linear flutter analysis methods. Different from the routine procedures of the ELM, the frequency rather than the amplitude of limit cycle oscillation (LCO is chosen as an active increment to produce bifurcation charts. Numerical examples show that this modification makes the ELM much more efficient. Meanwhile, the LCOs obtained by the ELM are in good agreement with numerical solutions. The nonlinear damping can delay the occurrence of secondary bifurcation. On the other hand, it has marginal influence on bifurcation characteristics or LCOs.

  11. Design for coupled-mode flutter and non-synchronous vibration in turbomachinery

    Science.gov (United States)

    Clark, Stephen Thomas

    This research presents the detailed investigation of coupled-mode flutter and non-synchronous vibration in turbomachinery. Coupled-mode flutter and non-synchronous vibration are two aeromechanical challenges in designing turbomachinery that, when present, can cause engine blade failure. Regarding flutter, current industry design practices calculate the aerodynamic loads on a blade due to a single mode. In response to these design standards, a quasi three-dimensional, reduced-order modeling tool was developed for identifying the aeroelastic conditions that cause multi-mode flutter. This tool predicts the onset of coupled-mode flutter reasonable well for four different configurations, though certain parameters were tuned to agree with experimentation. Additionally, the results of this research indicate that mass ratio, frequency separation, and solidity have an effect on critical rotor speed for flutter. Higher mass-ratio blades require larger rotational velocities before they experience coupled-mode flutter. Similarly, increasing the frequency separation between modes and raising the solidity increases the critical rotor speed. Finally, and most importantly, design guidelines were generated for defining when a multi-mode flutter analysis is required in practical turbomachinery design. Previous work has shown that industry computational fluid dynamics can approximately predict non-synchronous vibration (NSV), but no real understanding of frequency lock-in and blade limit-cycle amplitude exists. Therefore, to understand the causes of NSV, two different reduced-order modeling approaches were used. The first approach uses a van der Pol oscillator to model a non-linear fluid instability. The van der Pol model is then coupled to a structural degree of freedom. This coupled system exhibits the two chief properties seen in experimental and computational non-synchronous vibration. Under various conditions, the fluid instability and the natural structural frequency will lock

  12. A Study on Fluid Self-Excited Flutter and Forced Response of Turbomachinery Rotor Blade

    Directory of Open Access Journals (Sweden)

    Chih-Neng Hsu

    2014-01-01

    Full Text Available Complex mode and single mode approach analyses are individually developed to predict blade flutter and forced response. These analyses provide a system approach for predicting potential aeroelastic problems of blades. The flow field properties of a blade are analyzed as aero input and combined with a finite element model to calculate the unsteady aero damping of the blade surface. Forcing function generators, including inlet and distortions, are provided to calculate the forced response of turbomachinery blading. The structural dynamic characteristics are obtained based on the blade mode shape obtained by using the finite element model. These approaches can provide turbine engine manufacturers, cogenerators, gas turbine generators, microturbine generators, and engine manufacturers with an analysis system to remedy existing flutter and forced response methods. The findings of this study can be widely applied to fans, compressors, energy turbine power plants, electricity, and cost saving analyses.

  13. Flutter Characteristic Study of Composite Sandwich Panel with Functionally Graded Foam Core

    Directory of Open Access Journals (Sweden)

    Peng Jin

    2016-01-01

    Full Text Available This paper attempts to investigate the flutter characteristic of sandwich panel composed of laminated facesheets and a functionally graded foam core. The macroscopic properties of the foam core change continuously along this direction parallel to the facesheet lamina. The model used in the study is a simple sandwich panel-wing clamped at the root, with three simple types of grading strategies for FGM core: (1 linear grading strategy in the chord-wise direction, (2 linear grading strategy in the span-wise direction, and (3 bilinear grading of properties of foam core across the panel. The results show that use of FGM core has the potential to increase the flutter speed of the sandwich panel. Finally, a minimum weight design of composite sandwich panel with lamination parameters of facesheet and density distribution of foam core as design variables is conducted using particle swarm optimization (PSO.

  14. Comparison of Temporal Parameters of Swimming Rescue Elements When Performed Using Dolphin and Flutter Kick with Fins - Didactical Approach

    Science.gov (United States)

    Rejman, Marek; Wiesner, Wojciech; Silakiewicz, Piotr; Klarowicz, Andrzej; Abraldes, J. Arturo

    2012-01-01

    The aim of this study was an analysis of the time required to swim to a victim and tow them back to shore, while perfoming the flutter-kick and the dolphin-kick using fins. It has been hypothesized that using fins while using the dolphin-kick when swimming leads to reduced rescue time. Sixteen lifeguards took part in the study. The main tasks performed by them, were to approach and tow (double armpit) a dummy a distance of 50m while applying either the flutter-kick, or the dolphin-kick with fins. The analysis of the temporal parameters of both techniques of kicking demonstrates that, during the approach to the victim, neither the dolphin (tmean = 32.9s) or the flutter kick (tmean = 33.0s) were significantly faster than the other. However, when used for towing a victim the flutter kick (tmean = 47.1s) was significantly faster when compared to the dolphin-kick (tmean = 52.8s). An assessment of the level of technical skills in competitive swimming, and in approaching and towing the victim, were also conducted. Towing time was significantly correlated with the parameter that linked the temporal and technical dimensions of towing and swimming (difference between flutter kick towing time and dolphin-kick towing time, 100m medley time and the four swimming strokes evaluation). No similar interdependency has been discovered in flutter kick towing time. These findings suggest that the dolphin-kick is a more difficult skill to perform when towing the victim than the flutter-kick. Since the hypothesis stated was not confirmed, postulates were formulated on how to improve dolphin-kick technique with fins, in order to reduce swimming rescue time. Key points The source of reduction of swimming rescue time was researched. Time required to approach and to tow the victim while doing the flutter kick and the dolphin-kick with fins was analyzed. The propulsion generated by dolphin-kick did not make the approach and tow faster than the flutter kick. More difficult skill to realize of

  15. Cost-effectiveness of dronedarone in patients with atrial fibrillation in the ATHENA trial.

    Science.gov (United States)

    Berg, Jenny; Sauriol, Luc; Connolly, Stuart; Lindgren, Peter

    2013-10-01

    The ATHENA trial randomized 4628 patients with atrial fibrillation (AF) or atrial flutter, aged ≥ 70 years with risk factors or ≥ 75 years without risk factors, to receive 400 mg dronedarone twice daily or placebo in addition to standard therapy. Our objective was to evaluate the cost-effectiveness of dronedarone from a Canadian health care perspective based on resource utilization and cardiovascular hospitalization or death in ATHENA. Data on medical resource utilization (cardiovascular hospitalizations, hospitalization because of treatment-related adverse events, outpatient examinations and procedures, study drug and concomitant medications) were aggregated for all randomized patients during the entire trial period (mean 21 months). Effectiveness was measured using the total number of avoided cardiovascular hospitalizations and deaths from any cause, and projected survival and quality-adjusted survival using life tables adjusted for AF mortality and data on determinants of utility in AF. We used standard unit costs from Canada (2008), discounting costs and effects at 5% per year. Patients receiving dronedarone incurred a mean total cost (undiscounted) of CAD $7402 during the trial period, compared with CAD $6708 for patients receiving placebo. The cost of dronedarone was partly offset by savings for cardiovascular hospitalizations and concomitant medications. On average, patients taking dronedarone experienced 0.18 fewer events (cardiovascular hospitalizations or death). The cost per event avoided was CAD $3807, the cost per life-year gained was CAD $5204, and the cost per quality-adjusted life-years was CAD $7560. Compared with generally accepted thresholds, our results indicate that treatment with dronedarone as in ATHENA is cost-effective. Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  16. Environmental Effects on Flutter Characteristics of Laminated Composite Rectangular and Skew Panels

    Directory of Open Access Journals (Sweden)

    T.V.R. Chowdary

    1996-01-01

    Full Text Available A finite element method is presented for predicting the flutter response of laminated composite panels subjected to moisture concentration and temperature. The analysis accounts for material properties at elevated temperature and moisture concentration. The analysis is based on the first-order approximation to the linear piston theory and laminated plate theory that includes shear deformation. Both rectangular and skew panels are considered. Stability boundaries at moisture concentrations and temperatures for various lamination schemes and boundary conditions are discussed.

  17. Echolocation behavior of the Japanese horseshoe bat in pursuit of fluttering prey.

    Science.gov (United States)

    Mantani, Shigeki; Hiryu, Shizuko; Fujioka, Emyo; Matsuta, Naohiro; Riquimaroux, Hiroshi; Watanabe, Yoshiaki

    2012-10-01

    Echolocation sounds of Rhinolophus ferrumequinum nippon as they approached a fluttering moth (Goniocraspidum pryeri) were investigated using an on-board telemetry microphone (Telemike). In 40% of the successful moth-capture flights, the moth exhibited distinctive evasive flight behavior, but the bat pursued the moth by following its flight path. When the distance to the moth was approximately 3-4 m, the bats increased the duration of the pulses to 65-95 ms, which is 2-3 times longer than those during landing flight (30-40 ms). The mean of 5.8 long pulses were emitted before the final buzz phase of moth capture, without strengthening the sound pressure level. The mean duration of long pulses (79.9 ± 7.9 ms) corresponded to three times the fluttering period of G. pryeri (26.5 × 3 = 79.5 ms). These findings indicate that the bats adjust the pulse duration to increase the number of temporal repetitions of fluttering information rather than to produce more intense sonar sounds to receive fine insect echoes. The bats exhibited Doppler-shift compensation for echoes returning from large static objects ahead, but not for echoes from target moths, even though the bats were focused on capturing the moths. Furthermore, the echoes of the Telemike recordings from target moths showed spectral glints of approximately 1-1.5 kHz caused by the fluttering of the moths but not amplitude glints because of the highly acoustical attenuation of ultrasound in the air, suggesting that spectral information may be more robust than amplitude information in echoes during moth capturing flight.

  18. A Study on Fluid Self-Excited Flutter and Forced Response of Turbomachinery Rotor Blade

    OpenAIRE

    Chih-Neng Hsu

    2014-01-01

    Complex mode and single mode approach analyses are individually developed to predict blade flutter and forced response. These analyses provide a system approach for predicting potential aeroelastic problems of blades. The flow field properties of a blade are analyzed as aero input and combined with a finite element model to calculate the unsteady aero damping of the blade surface. Forcing function generators, including inlet and distortions, are provided to calculate the forced response of tu...

  19. Flutter Instability of a Fluid-Conveying Fluid-Immersed Pipe Affixed to a Rigid Body

    Science.gov (United States)

    2011-01-01

    304–307. Bourri eres, F.-J., 1939. Sur en phenomene d’oscillation auto entrenue en mecanique des fluides reels. Publications Scientifiques et...Flutter instability of a fluid -conveying fluid -immersed pipe affixed to a rigid body Aren Helluma, Ranjan Mukherjee a,, Andrew J. Hull b a...Article history: Received 28 June 2010 Accepted 11 March 2011 Available online 6 April 2011 Keywords: Fluid -conveying pipe Fluid -immersed pipe External

  20. Magnetic resonance imaging of suspected atrial tumors.

    Science.gov (United States)

    Menegus, M A; Greenberg, M A; Spindola-Franco, H; Fayemi, A

    1992-05-01

    Two-dimensional echocardiography has become the standard technique for evaluation of cardiac and paracardiac mass lesions. We have used magnetic resonance imaging (MRI) as an independent assessment of cardiac-associated masses in patients with echocardiograms demonstrating sessile atrial tumors. MRI was performed in seven patients, ages 33 to 84, whose echocardiographic diagnoses included left atrial mass (five), right atrial mass (one), and interatrial mass (one). In four of the patients with a diagnosis of left atrial mass, MRI showed extracardiac compression of the atrium, simulating a tumor (hiatal hernia, tortuous descending aorta, bronchogenic cyst). MRI was entirely normal in one patient with an apparent left atrial mass. MRI elucidated extension of an extracavitary mass into the interatrial septum in two patients. One of these patients with an echocardiographic right atrial mass had extension of a lipoma into the interatrial septum without atrial tumor. MRI confirmed the echocardiographic diagnosis of an interatrial mass in the other patient. We conclude that MRI, because of its ability to define anatomic relationships and tissue characteristics, is a powerful noninvasive tool for evaluating suspected cardiac mass lesions. Although echocardiography remains the primary screening test for the detection of cardiac masses, MRI is a more specific modality for precise diagnosis. Correct MRI interpretation may obviate the need for invasive studies or surgery.

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    BACKGROUND: Postoperative atrial fibrillation is a common complication to cardiac surgery. Na,K-ATPase is of major importance for the resting membrane potential and action potential. The purpose of the present study was to evaluate the importance of Na,K-ATPase concentrations in human atrial...... biopsies and plasma potassium concentrations for the development of atrial fibrillation. METHODS: Atrial myocardial biopsies were obtained from 67 patients undergoing open chest cardiac surgery. Na,K-ATPase was quantified using vanadate-facilitated 3H-ouabain binding. Plasma potassium concentration...... with postoperative atrial fibrillation. CONCLUSIONS: The present study supports the increasing evidence of dysregulation of the potassium homeostasis as an important factor in the development of cardiac arrhythmias. High atrial Na,K-ATPase and sudden plasma potassium concentration increase may contribute...

  2. Identification of reduced-order model for an aeroelastic system from flutter test data

    Directory of Open Access Journals (Sweden)

    Wei Tang

    2017-02-01

    Full Text Available Recently, flutter active control using linear parameter varying (LPV framework has attracted a lot of attention. LPV control synthesis usually generates controllers that are at least of the same order as the aeroelastic models. Therefore, the reduced-order model is required by synthesis for avoidance of large computation cost and high-order controller. This paper proposes a new procedure for generation of accurate reduced-order linear time-invariant (LTI models by using system identification from flutter testing data. The proposed approach is in two steps. The well-known poly-reference least squares complex frequency (p-LSCF algorithm is firstly employed for modal parameter identification from frequency response measurement. After parameter identification, the dominant physical modes are determined by clear stabilization diagrams and clustering technique. In the second step, with prior knowledge of physical poles, the improved frequency-domain maximum likelihood (ML estimator is presented for building accurate reduced-order model. Before ML estimation, an improved subspace identification considering the poles constraint is also proposed for initializing the iterative procedure. Finally, the performance of the proposed procedure is validated by real flight flutter test data.

  3. Flutter analysis of a supersonic cascade in time domain using an ADI Euler solver

    Science.gov (United States)

    Reddy, T. S. R.; Bakhle, M. A.; Huff, D. L.

    1992-01-01

    The aeroelastic stability of a two-dimensional cascade oscillating in supersonic axial flow is analyzed in the time domain. The aeroelastic model consists of a single degree of freedom typical section structural model for each blade of the cascade and an unsteady two-dimensional cascade aerodynamic model based on the Euler equations. The Euler equations are solved using a time accurate Alternating Direction Implicit (ADI) solution scheme. The aeroelastic equations are integrated in time. The effect of interblade phase angle is included in the aeroelastic analysis by an appropriate choice of initial and boundary conditions. Flutter predictions are obtained from the time response of a flat plate cascade in single degree of freedom pitching motion. The results correlate well with those obtained from a separate frequency domain flutter analysis for all values of interblade phase angles considered. Flutter results are then presented for cascades having airfoil sections representative of a supersonic throughflow fan. The validity of the time integration method for a cascade of airfoils at various interblade phase angles is demonstrated.

  4. Economical Unsteady High-Fidelity Aerodynamics for Structural Optimization with a Flutter Constraint

    Science.gov (United States)

    Bartels, Robert E.; Stanford, Bret K.

    2017-01-01

    Structural optimization with a flutter constraint for a vehicle designed to fly in the transonic regime is a particularly difficult task. In this speed range, the flutter boundary is very sensitive to aerodynamic nonlinearities, typically requiring high-fidelity Navier-Stokes simulations. However, the repeated application of unsteady computational fluid dynamics to guide an aeroelastic optimization process is very computationally expensive. This expense has motivated the development of methods that incorporate aspects of the aerodynamic nonlinearity, classical tools of flutter analysis, and more recent methods of optimization. While it is possible to use doublet lattice method aerodynamics, this paper focuses on the use of an unsteady high-fidelity aerodynamic reduced order model combined with successive transformations that allows for an economical way of utilizing high-fidelity aerodynamics in the optimization process. This approach is applied to the common research model wing structural design. As might be expected, the high-fidelity aerodynamics produces a heavier wing than that optimized with doublet lattice aerodynamics. It is found that the optimized lower skin of the wing using high-fidelity aerodynamics differs significantly from that using doublet lattice aerodynamics.

  5. Flutter Analysis of a Morphing Wing Technology Demonstrator: Numerical Simulation and Wind Tunnel Testing

    Directory of Open Access Journals (Sweden)

    Andreea KOREANSCHI

    2016-03-01

    Full Text Available As part of a morphing wing technology project, the flutter analysis of two finite element models and the experimental results of a morphing wing demonstrator equipped with aileron are presented. The finite element models are representing a wing section situated at the tip of the wing; the first model corresponds to a traditional aluminium upper surface skin of constant thickness and the second model corresponds to a composite optimized upper surface skin for morphing capabilities. The two models were analyzed for flutter occurrence and effects on the aeroelastic behaviour of the wing were studied by replacing the aluminium upper surface skin of the wing with a specially developed composite version. The morphing wing model with composite upper surface was manufactured and fitted with three accelerometers to record the amplitudes and frequencies during tests at the subsonic wind tunnel facility at the National Research Council. The results presented showed that no aeroelastic phenomenon occurred at the speeds, angles of attack and aileron deflections studied in the wind tunnel and confirmed the prediction of the flutter analysis on the frequencies and modal displacements.

  6. Prediction and control of coupled-mode flutter in future wind turbine blades

    Science.gov (United States)

    Modarres-Sadeghi, Yahya; Currier, Todd; Caracoglia, Luca; Lackner, Matthew; Hollot, Christopher

    2017-11-01

    Coupled-mode flutter can be observed in future offshore wind turbine blades. We have shown this fact by considering various candidate blade designs, in all of which the blade's first torsional mode couples with one of its flapwise modes, resulting in coupled-mode flutter. We have shown how the ratio of these two natural frequencies can result in blades with a critical flutter speed even lower than their rated speed, especially for blades with low torsional natural frequencies. We have also shown how the stochastic nature of the system parameters (as an example, due to uncertainties in the manufacturing process) can significantly influence the onset of instability. We have proposed techniques to predict the onset of these instabilities and the resulting limit-cycle response, and strategies to control them, by either postponing the onset of instability, or lowering the magnitude of the limit-cycle response. The work is supported by the National Science Foundation, Award CBET-1437988 and Collaborative Awards CMMI-1462646 and CMMI-1462774.

  7. The circadian variation of premature atrial contractions

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  8. COMPARISON OF TEMPORAL PARAMETERS OF SWIMMING RESCUE ELEMENTS WHEN PERFORMED USING DOLPHIN AND FLUTTER KICK WITH FINS - DIDACTICAL APPROACH

    Directory of Open Access Journals (Sweden)

    Marek Rejman

    2012-12-01

    Full Text Available The aim of this study was an analysis of the time required to swim to a victim and tow them back to shore, while perfoming the flutter-kick and the dolphin-kick using fins. It has been hypothesized that using fins while using the dolphin-kick when swimming leads to reduced rescue time. Sixteen lifeguards took part in the study. The main tasks performed by them, were to approach and tow (double armpit a dummy a distance of 50m while applying either the flutter-kick, or the dolphin-kick with fins. The analysis of the temporal parameters of both techniques of kicking demonstrates that, during the approach to the victim, neither the dolphin (tmean = 32.9s or the flutter kick (tmean = 33.0s were significantly faster than the other. However, when used for towing a victim the flutter kick (tmean = 47.1s was significantly faster when compared to the dolphin-kick (tmean = 52.8s. An assessment of the level of technical skills in competitive swimming, and in approaching and towing the victim, were also conducted. Towing time was significantly correlated with the parameter that linked the temporal and technical dimensions of towing and swimming (difference between flutter kick towing time and dolphin-kick towing time, 100m medley time and the four swimming strokes evaluation. No similar interdependency has been discovered in flutter kick towing time. These findings suggest that the dolphin-kick is a more difficult skill to perform when towing the victim than the flutter-kick. Since the hypothesis stated was not confirmed, postulates were formulated on how to improve dolphin-kick technique with fins, in order to reduce swimming rescue time

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

    Science.gov (United States)

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

    2017-08-15

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

  10. Avaliação da atividade elétrica atrial em pacientes submetidos ao tratamento cirúrgico da valvopatia mitral Evaluation of atrial electrical activity in patients operated on mitral valve disease

    Directory of Open Access Journals (Sweden)

    Cesar Augusto Ferreira

    2002-01-01

    Full Text Available INTRODUÇÃO: O acesso cirúrgico por esternotomia mediana e atriotomia subseptal clássica pode, em certos casos, resultar em má exposição da valva mitral. Incisões atriais alternativas otimizam a exposição da valva mitral mas podem interferir na atividade elétrica atrial pós-operatória. OBJETIVO: Padronizar método para investigar a atividade elétrica atrial para emprego em estudos comparativos de diferentes atriotomias em cardiopatas sumetidos à cirurgia cardíaca. MÉTODOS: Análise com eletrocardiograma convencional e de 24 h (sistema Holter, pré e pós-operatória, e cardioestimulação epicárdica pós-operatória pelo método de Narula, em 10 pacientes submetidos à correção de valvopatias mitrais. RESULTADOS: No pré-op., os pacientes em ritmo sinusal apresentaram ectopias supraventriculares, com episódios de taquicardia supraventricular em 57% dos casos, "flutter" atrial em 10% e ritmo juncional em 10%. Todos apresentaram ectopias ventriculares, de baixa incidência em 70% dos casos, e taquicardia ventricular não sustentada foi detectada em 30% dos pacientes. No pós-operatório, houve 40% de novas arritmias supraventriculares (fibrilação atrial, ritmo juncional, ritmo atrial baixo e taquicardia supraventricular paroxística, mas não ocorreram arritmias ventriculares. No pós-op. a função do nó sinusal não se alterou, ocorreu redução significativa das ectopias supraventriculares, com reversão de FA para ritmo sinusal em 1 paciente, mas não houve redução significativa das ectopias ventriculares. O tempo de condução inter-atrial correlacionou-se com o tamanho do átrio esquerdo. CONCLUSÃO: A metodologia mostrou-se adequada e segura, e poderá ser empregada na comparação de diferentes incisões atriais para exposição valvar mitral.INTRODUCTION: The selection of the surgical approach to the mitral valve is a critical factor in obtaining good exposure and minimizing lesions of the surrounding structures

  11. Chocolate intake and risk of clinically apparent atrial fibrillation: the Danish Diet, Cancer, and Health Study.

    Science.gov (United States)

    Mostofsky, Elizabeth; Berg Johansen, Martin; Tjønneland, Anne; Chahal, Harpreet S; Mittleman, Murray A; Overvad, Kim

    2017-08-01

    To evaluate the association between chocolate intake and incident clinically apparent atrial fibrillation or flutter (AF). The Danish Diet, Cancer, and Health Study is a large population-based prospective cohort study. The present study is based on 55 502 participants (26 400 men and 29 102 women) aged 50-64 years who had provided information on chocolate intake at baseline. Incident cases of AF were ascertained by linkage with nationwide registries. During a median of 13.5 years there were 3346 cases of AF. Compared with chocolate intake less than once per month, the rate of AF was lower for people consuming 1-3 servings/month (hazard ratio (HR) 0.90, 95% confidence interval (CI) 0.82 to 0.98), 1 serving/week (HR 0.83, 95% CI 0.74 to 0.92), 2-6 servings/week (HR 0.80, 95% CI 0.71 to 0.91) and ≥1 servings/day (HR 0.84, 95% CI 0.65 to 1.09; p-linear trend chocolate intake may be inversely associated with AF risk, although residual confounding cannot be ruled out. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  12. Left atrial and left atrial appendage function in paroxysmal atrial fibrillation.

    Science.gov (United States)

    Erdei, T; Erdei, Tamás; Dénes, M; Kardos, A; Földesi, C; Földesi, A; Temesvári, A; Temesvári, M; Lengyel, M

    2011-06-01

    In patients with paroxysmal atrial fibrillation (PAF) little information is available about left atrial (LA)function, and there is less information about LA appendage (LAA) function, and about their relations. 46 patients were selected for catheter ablation (CA) because of nonvalvular PAF.Transthoracic, tissue Doppler and transoesophageal echocardiography was performed before CA. LA volumes and volume index (LAVI) were calculated. LA function was assessed by LA filling fraction (LAFF), LA emptying fraction (LAEF), systolic fraction of pulmonary venous flow (PVSF) and late diastolic velocities of mitral annulus(Aa,, A5at) LAA function was assessed by peak LAA emptying flow velocity (PLAAEFV). Diastolic dysfunction(DD) was also assessed. Dilated LAVI in 32, LA dysfunction in 20, DD with elevated LV filling pressure in 19 patients was found. Aa,at and Aa,p correlated with LAFF (r:0.53; p<0.001 and r:0.43; p<0.05), LAEF (r:0.51;p<0.001 and r:0.63; p<0.001), PVSF (r:0.49; p<0.001 and r:0.46; p<0.005) and PLAAEFV (r:0.58; p<0.001 and r:0.45; p<0.01). In PAF patients Aa velocity is useful to assess LA function and correlates positively with other TTE derived LA functional parameters and LAA function by TEE derived PLAAEFV.

  13. Uso da radiofrequência bipolar para o tratamento da fibrilação atrial durante cirurgia cardíaca

    Directory of Open Access Journals (Sweden)

    Leonardo Secchin Canale

    2011-06-01

    Full Text Available FUNDAMENTO: O tratamento da fibrilação atrial com dispositivo de ablação de tecidos por radiofrequência bipolar em concomitância à cirurgia cardíaca tem se mostrado método eficaz no tratamento desta arritmia. OBJETIVO: Descrever a experiência inicial do Instituto Nacional de Cardiologia no tratamento cirúrgico da fibrilação atrial com uso de dispositivo de radiofrequência bipolar em pacientes submetidos à cirurgia cardíaca, relatando o resultado de acompanhamento pós-operatório de um ano. MÉTODOS: Entre janeiro de 2008 e março de 2009, 47 pacientes (36 mulheres consecutivos, com idade média de 53,7 ± 10,6 anos, apresentando fibrilação atrial por um período médio de 34,6 meses (3 a 192 meses foram submetidos à ablação cirúrgica desta arritmia, por radiofrequência bipolar, durante o procedimento que motivou a indicação da cirurgia. Oito apresentavam fibrilação atrial intermitente e 39, contínua. Oitenta e um por cento foram submetidos à cirurgia valvar como procedimento principal. Esta é uma análise retrospectiva, observacional, com avaliação de um ano de pós-operatório das variáveis clínicas e de Holter 24 h. RESULTADOS: Dos 47 pacientes, 40 sobreviveram um ano. Desses, 33 foram submetidos a Holter 24 h, em um intervalo médio de 401 dias após a cirurgia. Encontrou-se a seguinte distribuição de ritmos: 24 (73% sinusal, 5 (15% fibrilação atrial, três (9% Flutter atrial e um (3% ritmo juncional. Foram observados dois acidentes vasculares encefálicos, sendo um associado à arritmia supraventricular. CONCLUSÃO: A ablação cirúrgica de fibrilação atrial com dispositivo de radiofrequência bipolar concomitante à cirurgia cardíaca é método eficaz para o tratamento desta arritmia.

  14. Towards Low Energy Atrial Defibrillation

    Directory of Open Access Journals (Sweden)

    Philip Walsh

    2015-09-01

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

  15. Alcohol consumption and risk of atrial fibrillation

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  16. POSTOPERATIVE ATRIAL FIBRILLATION – AN UPDATE

    Directory of Open Access Journals (Sweden)

    Johnson Francis

    2015-12-01

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

  17. Psychosomatic correlations in atrial fibrillations

    Directory of Open Access Journals (Sweden)

    Vladimir Ernstovich Medvedev

    2011-01-01

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

  18. Dronedarone for atrial fibrillation therapy.

    Science.gov (United States)

    Marzocchi, Michele; Lombardi, Federico

    2011-06-01

    Dronedarone is a new benzofuran derivative that has been developed as an antiarrhythmic agent on the basis of the amiodarone molecular structure with the intent of maintaining the same pharmacological effects while reducing thyroid and pulmonary toxicity. The drug is a multichannel blocker with antiadrenergic properties: it reduces heart rate and prolongs the action potential duration. Dronedarone is primarily metabolized by cytochrome P450; its half-life is much shorter than that of amiodarone because of a lower lipophilicity. As a consequence, only 7 days are needed to reach steady-state plasma levels. It has been tested in clinical trials both for rate and rhythm control and, even if its antiarrhythmic efficacy seems to be somehow lower than that of amiodarone, dronedarone is less often discontinued due to adverse reactions or organic toxicity. For these reasons, dronedarone can be very useful in long-term treatment of atrial fibrillation, by reducing hospitalizations and mortality.

  19. Impact of left atrial size reduction on chronic atrial fibrillation in mitral valve surgery.

    Science.gov (United States)

    Scherer, Mirela; Dzemali, Omer; Aybek, Tayfun; Wimmer-Greinecker, Gerhard; Moritz, Anton

    2003-07-01

    Left atrial enlargement is a risk factor for the development of atrial fibrillation (AF). Large atrial size increases thromboembolic risk and reduces the success rate of cardioversion. The study aim was to evaluate if left atrial size reduction affects cardiac rhythm in patients with chronic AF undergoing mitral valve surgery. Twenty-seven patients were analyzed prospectively. The left atrial incision was extended to the left inferior pulmonary vein. Left atrial size reduction was achieved by closure of the left atrial appendage from inside with a double running suture. The same suture plicated the left lateral atrial wall to the roof of the left pulmonary vein inflow and the inferior atrial wall. The atrial septum was plicated by placing stitches of the closing suture line across the fossa ovalis. Rhythm, neurological complications, cardioversion, anticoagulation and anti-arrhythmic medication were evaluated at one year postoperatively and at recent follow up (mean 40 +/- 15 months). At discharge, five patients (19%) were in sinus rhythm (SR). At one year postoperatively, SR was restored in 17 patients (63%), but five (19%) reported episodes of arrhythmia and AF persisted in 10 (37%). At recent follow up, four patients had died and three were lost to follow up. Among 20 patients examined, 13 (65%) had SR but six reported episodes of arrhythmia and AF persisted in seven (35%). LA diameter was significantly reduced, from 60.2 +/- 9.8 mm preoperatively to 44.5 +/- 7.0 mm at one year after surgery. The addition of left atrial size reduction to mitral valve surgery is technically simple, and was effective in 63% of patients with chronic AF, restoring predominant SR. In order to influence pathogenetic factors other than size, additional ablative steps may further increase the SR conversion rate. Size reduction may also improve the outcome of other ablative approaches.

  20. Advances in Left Atrial Appendage Occlusion Strategies

    OpenAIRE

    Arash Aryana; Sheldon M. Singh; Shephal K. Doshi; Andr� d�Avila

    2013-01-01

    Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide and associated with an elevated risk of thromboembolic stroke and systemic embolization. The evidence suggests that ~90% of thrombi in patients with non-valvular AF are localized to the left atrial appendage (LAA). Therefore, it seems reasonable to consider LAA exclusion in selected patients with AF for stroke prevention. LAA exclusion can be achieved through a variety of surgical and percutaneous techniques. Surgical me...

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

    Science.gov (United States)

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

    2008-12-01

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

  2. Transonic flutter study of a 50.5 deg cropped-delta wing with two rearward-mounted nacelles

    Science.gov (United States)

    Sandford, M. C.; Ruhlin, C. L.; Abel, I.

    1974-01-01

    Transonic flutter characteristics of three geometrically similar delta-wing models were experimentally determined in the Langley transonic dynamics tunnel at Mach numbers from about 0.6 to 1.2. The models were designed to be simplified versions of an early supersonic transport wing design. The model was an aspect-ratio-1.28 cropped-delta wing with a leadingedge sweep of 50.5 deg. The flutter characteristics obtained for this wing configuration indicated a minimum flutter-speed index near a Mach number of 0.92 and a transonic compressibility dip amounting to about a 27-percent decrease in the flutter-speed index relative to the value at a Mach number of 0.6. Analytical studies were performed for one wing model at Mach numbers of 0.6, 0.7, 0.8, and 0.9 by using both doublet-lattice and lifting-surface (kernel-function) unsteady aerodynamic theory. A comparison of the analytical and experimental flutter results showed good agreement at all Mach numbers investigated.

  3. Electrophysiological pulmonary vein antrum isolation with a multielectrode basket catheter is feasible and effective for curing paroxysmal atrial fibrillation: efficacy of minimally extensive pulmonary vein isolation.

    Science.gov (United States)

    Yamada, Takumi; Murakami, Yoshimasa; Okada, Taro; Okamoto, Mitsuhiro; Shimizu, Takeshi; Toyama, Junji; Yoshida, Yukihiko; Tsuboi, Naoya; Ito, Teruo; Muto, Masahiro; Kondo, Takahisa; Inden, Yasuya; Hirai, Makoto; Murohara, Toyoaki

    2006-04-01

    How extensive should an appropriate pulmonary vein (PV) ablation be is a matter of controversy. The study's aim was to investigate the efficacy of minimally extensive PV ablation for isolating the PV antrum (PVA) with the guidance of electrophysiological parameters. Fifty-five consecutive symptomatic paroxysmal atrial fibrillation (PAF) patients underwent PV mapping with a multielectrode basket catheter (MBC). A 31-mm MBC was deployed in 3-4 PVs as proximally as possible without dislodgement, and the longitudinal PV mapping enabled us to recognize single sharp potentials formed by the total fusion of the PV and left atrial potentials around the PV ostium or the transverse activation patterns that were observed. Those potentials were defined as PVA potentials. Radiofrequency ablation was performed circumferentially targeting PVA potentials with the end point being their elimination. After circumferential PVA ablation, electrical disconnection was achieved in 77% and residual PVA conduction gaps were observed in 23% of all targeted PVs. Those residual conduction gaps were mainly located at the border between ipsilateral PVs (42%) and between the left PVs and left atrial appendage (33%) and were eliminated by a mean of 3 +/- 2 minutes of local radiofrequency deliveries. During the follow-up period (11 +/- 5 months), 46 (84%) patients were free of symptomatic PAF without any anti-arrhythmic drugs. No PV stenosis or spontaneous left atrial flutter occurred. Electrophysiological PVA ablation with an MBC is feasible and effective for curing PAF because this minimally extensive PVA isolation technique targets the optimal sites, achieving both high efficacy and safety.

  4. Dynamic and dual-site atrial pacing in the prevention of atrial fibrillation: The STimolazione Atrial DInamica Multisito (STADIM) Study.

    Science.gov (United States)

    De Simone, Antonio; Senatore, Gaetano; Donnici, Giovanni; Turco, Pietro; Romano, Enrico; Gazzola, Carlo; Stabile, G

    2007-01-01

    The impact of new algorithms to consistently pace the atrium on the prevention of atrial fibrillation (AF) remains unclear. Our randomized, crossover study compared the efficacy of single- and dual-site atrial pacing, with versus without dynamic atrial overdrive pacing in preventing AF. We studied 72 patients (mean age = 69.6 +/- 6.5 years, 34 men) with sick sinus syndrome (SSS) and paroxysmal or persistent AF, who received dual-chamber pacemakers (PM) equipped with an AF prevention algorithm and two atrial leads placed in the right atrial appendage (RAA), by passive fixation, and in the coronary sinus ostium (CS), by active fixation, respectively. At implant, the patients were randomly assigned to unipolar CS versus RAA pacing. The PM was programmed in DDDR mode 1 month after implant. Each patient underwent four study phases of equal duration: (1) unipolar, single site (CS or RAA) pacing with the AF algorithm ON (atrial lower rate = 0 ppm); (2) unipolar, single site pacing with the AF algorithm OFF (atrial lower rate = 70 bpm); (3) bipolar, dual-site pacing with AF algorithm ON; (4) bipolar, dual-site pacing with the AF algorithm OFF. Among 40 patients (56%), who completed the follow-up (15 +/- 4 months) no difference was observed in the mean number of automatic mode switch (AMS) corrected for the duration of follow-up, in unipolar (5.6 +/- 22.8 vs 2.6 +/- 5.5) or bipolar mode (3.3 +/- 12.7 vs 2.1 +/- 4.9) with, respectively, the algorithm OFF or ON. With the AF prevention algorithm ON, the percentage of atrial pacing increased significantly from 78.7 +/- 22.1% to 92.4 +/- 4.9% (P < 0.001), while the average ventricular heart rate was significantly lower with the algorithm ON (62.4 +/- 17.5 vs 79.9 +/- 3 bpm (P < 0.001). The AF prevention algorithm increased the percentage of atrial pacing significantly, regardless of the atrial pulse configuration and pacing site, while maintaining a slower ventricular heart rate. It had no impact on the number of AMS in the

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

    Science.gov (United States)

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

    2016-11-01

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

  6. The development of the DAST I remotely piloted research vehicle for flight testing an active flutter suppression control system. Ph.D. Thesis. Final Report

    Science.gov (United States)

    Grose, D. L.

    1979-01-01

    The development of the DAST I (drones for aerodynamic and structural testing) remotely piloted research vehicle is described. The DAST I is a highly modified BQM-34E/F Firebee II Supersonic Aerial Target incorporating a swept supercritical wing designed to flutter within the vehicle's flight envelope. The predicted flutter and rigid body characteristics are presented. A description of the analysis and design of an active flutter suppression control system (FSS) designed to increase the flutter boundary of the DAST wing (ARW-1) by a factor of 20% is given. The design and development of the digital remotely augmented primary flight control system and on-board analog backup control system is presented. An evaluation of the near real-time flight flutter testing methods is made by comparing results of five flutter testing techniques on simulated DAST I flutter data. The development of the DAST ARW-1 state variable model used to generate time histories of simulated accelerometer responses is presented. This model uses control surface commands and a Dryden model gust as inputs. The feasibility of the concept of extracting open loop flutter characteristics from closed loop FSS responses was examined. It was shown that open loop characteristics can be determined very well from closed loop subcritical responses.

  7. Longstanding atrial fibrillation causes depletion of atrial natriuretic peptide in patients with advanced congestive heart failure

    NARCIS (Netherlands)

    van den Berg, MP; de Kam, PJ; Boomsma, F; Crijns, HJGM; van Veldhuisen, DJ

    Background: Congestive heart failure (CHF) is characterized by neurohormonal activation, including increased plasma concentrations of atrial natriuretic peptide (ANP) and N-terminal ANP (N-ANP). Onset of atrial fibrillation (AF) further increases these peptides, but it may be hypothesized that

  8. Epicardial Ablation of Focal Atrial Tachycardia Arising From Left Atrial Appendage in Children

    Directory of Open Access Journals (Sweden)

    Abdhija Hanumandla

    2014-07-01

    Full Text Available Focal left atrial tachycardia (FLAT although a common cause of supraventricular tachycardia(SVT among children, the one's arising from left atrial appendage (LAA present a unique challenge for successful ablation because of anatomical location. We present two children with FLAT arising from the epicardial LAA, successfully mapped and ablated through percutaneuous epicardial approach.

  9. Left Atrial Sphericity Index Predicts Early Recurrence of Atrial Fibrillation After Direct-Current Cardioversion

    DEFF Research Database (Denmark)

    Osmanagic, Armin; Möller, Sören; Osmanagic, Azra

    2016-01-01

    BACKGROUND: Attempts to achieve rhythm control using direct-current cardioversion (DCC) are common in those with persistent atrial fibrillation (AF). Although often successful, AF recurs within 1 month in as many as 57% of patients. The aim of this study was to assess whether a baseline left atrial...

  10. Atrial defibrillation threshold in humans minutes after atrial fibrillation induction; "A stitch in time saves nine".

    Science.gov (United States)

    Vardas, P E; Manios, E G; Kanoupakis, E M; Dermitzaki, D N; Mavrakis, H E; Kallergis, E M

    2001-09-01

    To assess the effects of atrial fibrillation duration on the defibrillation threshold in atrial fibrillation patients seconds or minutes after initiation of the arrhythmia. Nineteen patients with recurrent symptomatic atrial fibrillation were evaluated. After programmed induction of atrial fibrillation, the defibrillation threshold was assessed after two sequential periods of arrhythmia in the same patient: an "ultrashort" period of 30 s duration and a "short" period, which lasted 10 min. After the specified period, internal cardioversion was attempted using a balloon-guided catheter that allows the delivery of biphasic shocks between one electrode array placed in the left pulmonary artery and a proximal electrode array on the lateral right atrial wall. The defibrillation threshold was assessed with energy steps of 0.5 J with a starting level of 0.5 J. Mean time from induction to successful defibrillation was 92+/-30 s after the "ultrashort" period of atrial fibrillation and 910+/-86 s after the short period. The defibrillation threshold was significantly greater after 10 min of atrial fibrillation than after 30 s of arrhythmia (2.32+/-0.61 J vs 1.31+/-0.66 J, Pdefibrillation threshold. Prolongation of atrial fibrillation over minutes in patients with paroxysmal arrhythmia increases the energy requirements for successful defibrillation. Copyright 2001 The European Society of Cardiology.

  11. Minimally invasive hybrid ablation procedure for the treatment of persistent atrial fibrillation: one year results.

    Science.gov (United States)

    Zembala, Michał; Filipiak, Krzysztof; Kowalski, Oskar; Boidol, Joanna; Sokal, Adam; Lenarczyk, Radosław; Niklewski, Tomasz; Garbacz, Marcin; Nadziakiewicz, Paweł; Kalarus, Zbigniew; Zembala, Marian

    2012-01-01

    The concept of a hybrid approach, combining the most effective techniques of surgical and endocardial catheter ablation has resulted in the creation of the convergent ablation procedure. This novel, pericardioscopic, hybrid approach can be an effective option for highly symptomatic patients with persistent atrial fibrillation (PSAF) and longstanding persistent atrial fibrillation (LSPAF) for whom standalone surgical or endocardial ablation procedures offer sometimes unsatisfactory outcomes. To assess the safety, efficacy and effectiveness of a hybrid epicardial and endocardial radiofrequency ablation for the treatment of PSAF and LSPAF. Single-centre, prospective, non-randomised clinical study. Between August 2009 and December 2011, 27 patients with PSAF (n = 5) and LSPAF (n = 22) underwent hybrid ablation (HABL). Mean age was 52.52 ± 11.27 years, and the mean EHRA class was 2.5; 14 (51.8%) patients had a history of electrical cardioversion (n = 6) or catheter ablation (n = 8). Five patients had left ventricular ejection fraction (LVEF) of less than 35%. Mean AF duration for all patients was 3.46 ± 2.5 years. All patients were on antiarrhythmic drugs (AAD) and oral anticoagulation. Patients were scheduled for three, six and 12 month follow-up with seven day Holters, REVEAL® XT and ECHO measurements. The HABL procedure was feasible in all patients. At six months post procedure, 72.2% (13/18) of patients were in SR, and 66.5% (12/18) were off class I/III AADs. Four patients were in AF and one patient developed right atrial flutter. At one year post procedure, 80% (8/10) of patients were in SR and off class I/III AADs. At two year post procedure, 100% (6/6) of patients were in SR and off class I/III AADs. Rapid change in left ventricular function was noted in patients with low LVEF (≤ 35%) prior to the procedure. Patients with LVEF +40% had less apparent improvement. Hybrid, epicardial and endocardial, radiofrequency ablation is feasible and safe, effectively

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

    Directory of Open Access Journals (Sweden)

    Matthias Bossard

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

  13. Effects of novel oral anticoagulants on left atrial and left atrial appendage thrombi: an appraisal.

    Science.gov (United States)

    Marsico, Fabio; Cecere, Milena; Parente, Antonio; Paolillo, Stefania; de Martino, Fabiana; Dellegrottaglie, Santo; Trimarco, Bruno; Perrone Filardi, Pasquale

    2017-02-01

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and predisposes to an increased risk of thromboembolic events. Patients affected by AF exhibit an increased risk of stroke compared with those in sinus rhythm, with the most common location of thrombi in the left atrial appendage. Until 2009, warfarin and other vitamin K antagonists were the only class of oral anticoagulants available. More recently, dabigatran, rivaroxaban, apixaban, and edoxaban have been approved by regulatory authorities for prevention of stroke in patients with non-valvular AF. Few data are available about the efficacy of novel oral anticoagulants for the treatment of left atrial and left atrial appendage thrombosis. Aim of this review is to summarize available evidence regarding the effectiveness of novel oral anticoagulants on left atrial appendage thrombosis.

  14. Transonic flutter analysis of an AGARD 445.6 wing in the frequency domain using the Euler method

    Directory of Open Access Journals (Sweden)

    Bocheng Zhang

    2016-01-01

    Full Text Available A method based on the Euler equations is proposed for solving transonic flutter problems. The transonic nonlinear flow field with local shock wave/boundary layer interaction is obtained by the Euler/boundary layer equations, and the aerodynamic forces are converted from the time domain to the frequency domain using system identification techniques. The structural dynamic equations in generalized coordinates are adopted for solving structure problems. The method is validated by a flutter boundary prediction of the AGARD 445.6 wing model. The simulation results show that the method presented in this paper is accurate for the prediction of transonic flutter boundary through comparison with experimental data and other simulation results. Furthermore, the present frequency domain method is also much more efficient than the time domain method.

  15. Differential atrial performance at rest and exercise in athletes: Potential trigger for developing atrial dysfunction?

    Science.gov (United States)

    Gabrielli, L; Bijnens, B H; Brambila, C; Duchateau, N; Marin, J; Sitges-Serra, I; Mont, L; Brugada, J; Sitges, M

    2016-12-01

    Highly trained athletes show an increased risk of atrial arrhythmias. Little is known about atrial volumes and function during exercise in this population. Our aim was to analyze atrial size and contractile function during exercise. Fifty endurance athletes with 11 ± 8 h of training per week and 30 sedentary control subjects were included. Echocardiography was performed at baseline and during exercise. Left (LA) and right atrial (RA) size and function were assessed by two-dimensional echocardiography. Peak negative strain (Sa) during atrial contraction and active atrial emptying volume (AEV) were measured. Athletes and control subjects showed a significant increment of deformation and AEV of both atria with exercise (P athletes, a subgroup with significant LA (n = 8)/RA (n = 15) dilatation (≥40 mL/m(2) ) showed a significantly lower increment in AEV with exercise (LA∆AEV: 1.4 ± 1.1 mL/m(2) vs 2.1 ± 0.9 mL/m(2) , P = 0.04; RA∆AEV: 0.9 ± 0.8 mL/m(2) vs 2.3 ± 1.1 mL/m(2) , P athletes (LA∆Sa: -3.2 ± 2.9% vs -9.5 ± 4.4%, P athletes compared to controls, but due to larger atrial volumes, they reached similar increases in atrial emptying volume. However, this overall lesser deformation increases from a subgroup with significant atrial dilatation showing impairment in atrial contractile reserve. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Mechanism for Triggered Waves in Atrial Myocytes.

    Science.gov (United States)

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

    2017-08-08

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

  17. Atrial tachyarrhythmia in adult congenital heart disease

    Science.gov (United States)

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

    2017-01-01

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

  18. Risk of atrial fibrillation and stroke in rheumatoid arthritis

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  19. A Wind-Tunnel Parametric Investigation of Tiltrotor Whirl-Flutter Stability Boundaries

    Science.gov (United States)

    Piatak, David J.; Kvaternik, Raymond G.; Nixon, Mark W.; Langston, Chester W.; Singleton, Jeffrey D.; Bennett, Richard L.; Brown, Ross K.

    2001-01-01

    A wind-tunnel investigation of tiltrotor whirl-flutter stability boundaries has been conducted on a 1/5-size semispan tiltrotor model known as the Wing and Rotor Aeroelastic Test System (WRATS) in the NASA-Langley Transonic Dynamics Tunnel as part of a joint NASA/Army/Bell Helicopter Textron, Inc. (BHTI) research program. The model was first developed by BHTI as part of the JVX (V-22) research and development program in the 1980's and was recently modified to incorporate a hydraulically-actuated swashplate control system for use in active controls research. The modifications have changed the model's pylon mass properties sufficiently to warrant testing to re-establish its baseline stability boundaries. A parametric investigation of the effect of rotor design variables on stability was also conducted. The model was tested in both the on-downstop and off-downstop configurations, at cruise flight and hover rotor rotational speeds, and in both air and heavy gas (R-134a) test mediums. Heavy gas testing was conducted to quantify Mach number compressibility effects on tiltrotor stability. Experimental baseline stability boundaries in air are presented with comparisons to results from parametric variations of rotor pitch-flap coupling and control system stiffness. Increasing the rotor pitch-flap coupling (delta(sub 3) more negative) was found to have a destabilizing effect on stability, while a reduction in control system stiffness was found to have little effect on whirl-flutter stability. Results indicate that testing in R-134a, and thus matching full-scale tip Mach number, has a destabilizing effect, which demonstrates that whirl-flutter stability boundaries in air are unconservative.

  20. Atrial fibrillation in elite athletes.

    Science.gov (United States)

    Furlanello, F; Bertoldi, A; Dallago, M; Galassi, A; Fernando, F; Biffi, A; Mazzone, P; Pappone, C; Chierchia, S

    1998-08-01

    Atrial fibrillation (AF) is a rare event in people younger than 25 years of age, but is probably more frequent in competitive athletes. We analyzed the presence of AF, paroxysmal or chronic, in a population of young elite athletes, including previous Olympic and World champions, who were studied for arrhythmias that endangered their athletic careers. From 1974 to June 1977, 1,772 athletes identified with arrhythmias (1,464 males and 308 females; mean age 21 years) underwent individualized work-ups. Among these, 146 (122 males and 24 females; mean age 24 years) were young elite athletes. They were studied from 1985 to 1997, with a mean follow-up of 62 months. Of the 146 young elite athletes, 13 (9%) had AF (paroxysmal in 11 and chronic in 2); all were male. The paroxysmal AF occurred during effort (n = 7), after effort (n = 1), or at rest (n = 3) and was reinduced by transesophageal pacing or endocavitary electrophysiologic testing under the same clinical circumstances. AF was the cause of symptoms in 13 (40%) of 22 young elite athletes with long-lasting palpitations. Five young elite athletes had a substrate for AF: Wolff-Parkinson-White syndrome (WPW) in 3, arrhythmogenic right ventricular dysplasia (ARVD) in 1, healed myocarditis in 1, and was considered idiopathic in 8. All elite athletes are alive with a mean follow-up of 62 months and 7 continue in their sports: 3 after radiofrequency catheter ablation (of WPW in 2 and AF with maze-type nonfluoroscopic approach in 1) and 4 after a period of de-training. AF, occurring in young elite athletes and affecting only males, is one of the most frequent causes of prolonged palpitations and is reproduced easily by transesophageal atrial pacing or electrophysiologic testing. AF may be a cause of disqualification from sports eligibility, but may disappear if the athletic activity is stopped for an adequate period of time, if trigger mechanisms are corrected (i.e., WPW), or if the substrate is modified.

  1. Optimization of structures to satisfy a flutter velocity constraint by use of quadratic equation fitting. M.S. Thesis

    Science.gov (United States)

    Motiwalla, S. K.

    1973-01-01

    Using the first and the second derivative of flutter velocity with respect to the parameters, the velocity hypersurface is made quadratic. This greatly simplifies the numerical procedure developed for determining the values of the design parameters such that a specified flutter velocity constraint is satisfied and the total structural mass is near a relative minimum. A search procedure is presented utilizing two gradient search methods and a gradient projection method. The procedure is applied to the design of a box beam, using finite-element representation. The results indicate that the procedure developed yields substantial design improvement satisfying the specified constraint and does converge to near a local optimum.

  2. Aero-servo-viscoelasticity theory: Lifting surfaces, plates, velocity transients, flutter, and instability

    Science.gov (United States)

    Merrett, Craig G.

    -partial differential equations. The spatial component of the governing equations is eliminated using a series expansion of basis functions and by applying Galerkin's method. The number of terms in the series expansion affects the convergence of the spatial component, and convergence is best determined by the von Koch rules that previously appeared for column buckling problems. After elimination of the spatial component, an ordinary integral-differential equation in time remains. The dynamic stability of elastic and viscoelastic problems is assessed using the determinant of the governing system of equations and the time component of the solution in the form exp (lambda t). The determinant is in terms of lambda where the values of lambda are the latent roots of the aero-servo-viscoelastic system. The real component of lambda dictates the stability of the system. If all the real components are negative, the system is stable. If at least one real component is zero and all others are negative, the system is neutrally stable. If one or more real components are positive, the system is unstable. In aero-servo-viscoelasticity, the neutrally stable condition is termed flutter. For an aero-servo-viscoelastic lifting surface, the unstable condition is historically termed torsional divergence. The more general aero-servo-viscoelastic theory has produced a number of important results, enumerated in the following list: 1. Subsonic panel flutter can occur before panel instability. This result overturned a long held assumption in aeroelasticity, and was produced by the novel application of the von Koch rules for convergence. Further, experimental results from the 1950s by the Air Force were retrieved to provide additional proof. 2. An expanded definition for flutter of a lifting surface. The legacy definition is that flutter is the first occurrence of simple harmonic motion of a structure, and the flight velocity at which this motion occurs is taken as the flutter speed. The expanded definition

  3. Experimental analysis of energy harvesting from self-induced flutter of a composite beam

    Energy Technology Data Exchange (ETDEWEB)

    Zakaria, Mohamed Y., E-mail: zakaria@vt.edu; Al-Haik, Mohammad Y.; Hajj, Muhammad R. [Virginia Tech, Norris Hall, Blacksburg, Virginia 24061 (United States)

    2015-07-13

    Previous attempts to harvest energy from aeroelastic vibrations have been based on attaching a beam to a moving wing or structure. Here, we exploit self-excited oscillations of a fluttering composite beam to harvest energy using piezoelectric transduction. Details of the beam properties and experimental setup are presented. The effects of preset angle of attack, wind speed, and load resistance on the levels of harvested power are determined. The results point to a complex relation between the aerodynamic loading and its impact on the static deflection and amplitudes of the limit cycle oscillations on one hand and the load resistance and level of power harvested on the other hand.

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

    LENUS (Irish Health Repository)

    Ridge, Carole A

    2012-02-01

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

  5. Rupture of the left atrial roof due to blunt trauma.

    Science.gov (United States)

    Ryu, Dae Woong; Lee, Sam Youn; Lee, Mi Kyung

    2013-11-01

    Cardiac rupture after blunt trauma is rare and associated with high mortality. The anatomic pattern of blunt cardiac rupture has been demonstrated with the right cardiac chambers more frequently affected than the left. Furthermore, left atrial injury is usually restricted to the atrial appendage and the pulmonary vein-atrial junction. Herein, we report the first case of a 61-year old man with a rupture of the left atrial roof after blunt trauma with minimal thoracic injury.

  6. Rupture of the left atrial roof due to blunt trauma

    OpenAIRE

    Ryu, Dae Woong; Lee, Sam Youn; Lee, Mi Kyung

    2013-01-01

    Cardiac rupture after blunt trauma is rare and associated with high mortality. The anatomic pattern of blunt cardiac rupture has been demonstrated with the right cardiac chambers more frequently affected than the left. Furthermore, left atrial injury is usually restricted to the atrial appendage and the pulmonary vein–atrial junction. Herein, we report the first case of a 61-year old man with a rupture of the left atrial roof after blunt trauma with minimal thoracic injury.

  7. [Electrophysiologic evaluation of athletes with Wolff-Parkinson-White syndrome: induction of supraventricular arrhythmia at rest and under exertion with transesophageal atrial electrostimulation].

    Science.gov (United States)

    Vergara, G; Furlanello, F; Disertori, M; Bettini, R; Stirpe, E; Inama, G; Guarnerio, M; Cozzi, F; Visonà, L; Frisanco, L

    1986-08-01

    The most suitable approach to the athletes with WPW is controversial. Therefore 66 symptom-free athletes with WPW and without heart disease (53 M, 13 F, mean age 21.98 yrs, min 12--max 44) underwent a study protocol whose end-point was the induction of supraventricular tachyarrhythmia, i.e. atrial fibrillation or, if not possible, atrial flutter or atrial tachycardia at rest and during ergometric stress test. The athletes with shortest R-R interval between preexcited beats less than or equal to 240 ms at rest and/or less than or equal to 210 ms during exercise were judged as being at risk i.e. no fit for sport activity. The end-point was reached in 64/66 athletes (in 62 atrial fibrillation). In 4 athletes with life threatening arrhythmia induced at rest the evaluation during exercise was not performed. According to the evaluation at rest we were able to identify only 18 athletes (28.1%) as being at risk, while according to the complete study protocol 26 athletes (40.6%) were judged as such. In 23/64 athletes (36%) this judgement was discordant with the usual non invasive evaluation (i.e. Holter monitoring, ergometric stress test, ajmaline test). During induced atrial fibrillation no significant difference, was found between the percentage of preexcited beats at rest and during exercise. On the average, 40 min. are required for performance of this study protocol (if the induced arrhythmia lasts less than 5 min.). According to our results we conclude: a) the non invasive assessment of the WPW athletes is unsatisfactory; b) the induction of atrial fibrillation during exercise gives a remarkable increase of the diagnostic power with respect to the assessment only at rest; c) since it is simple to perform and not expensive (in time, staff and cost) and because of its high diagnostic yield, we regard this protocol as fundamental for the electrophysiological evaluation of WPW athletes and also suitable for systematic study of WPW patients.

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

    NARCIS (Netherlands)

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

    2001-01-01

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

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

    DEFF Research Database (Denmark)

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

    1993-01-01

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

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    BACKGROUND: Different atrial arrhythmias can coexist in the recipient and donor atria after heart transplantation. CASE PRESENTATION: We report an unusual case of a patient with three different types of atrial arrhythmia after heart transplantation: an atrial fibrillation in the recipient atria, ...

  11. Effects of chronic atrial fibrillation on active and passive force generation in human atrial myofibrils.

    Science.gov (United States)

    Belus, Alexandra; Piroddi, Nicoletta; Ferrantini, Cecilia; Tesi, Chiara; Cazorla, Olivier; Toniolo, Luana; Drost, Maurice; Mearini, Giulia; Carrier, Lucie; Rossi, Alessandra; Mugelli, Alessandro; Cerbai, Elisabetta; van der Velden, Jolanda; Poggesi, Corrado

    2010-07-09

    Chronic atrial fibrillation (cAF) is associated with atrial contractile dysfunction. Sarcomere remodeling may contribute to this contractile disorder. Here, we use single atrial myofibrils and fast solution switching techniques to directly investigate the impact of cAF on myofilament mechanical function eliminating changes induced by the arrhythmia in atrial myocytes membranes and extracellular components. Remodeling of sarcomere proteins potentially related to the observed mechanical changes is also investigated. Myofibrils were isolated from atrial samples of 15 patients in sinus rhythm and 16 patients with cAF. Active tension changes following fast increase and decrease in [Ca(2+)] and the sarcomere length-passive tension relation were determined in the 2 groups of myofibrils. Compared to sinus rhythm myofibrils, cAF myofibrils showed (1) a reduction in maximum tension and in the rates of tension activation and relaxation; (2) an increase in myofilament Ca(2+) sensitivity; (3) a reduction in myofibril passive tension. The slow beta-myosin heavy chain isoform and the more compliant titin isoform N2BA were up regulated in cAF myofibrils. Phosphorylation of multiple myofilament proteins was increased in cAF as compared to sinus rhythm atrial myocardium. Alterations in active and passive tension generation at the sarcomere level, explained by translational and post-translational changes of multiple myofilament proteins, are part of the contractile dysfunction of human cAF and may contribute to the self-perpetuation of the arrhythmia and the development of atrial dilatation.

  12. [Left atrial appendage in rheumatic mitral valve disease: The main source of embolism in atrial fibrillation].

    Science.gov (United States)

    García-Villarreal, Ovidio A; Heredia-Delgado, José A

    To demonstrate that surgical removal of the left atrial appendage in patients with rheumatic mitral valve disease and long standing persistent atrial fibrillation decreases the possibility of stroke. This also removes the need for long-term oral anticoagulation after surgery. A descriptive, prospective, observational study was conducted on 27 adult patients with rheumatic mitral valve disease and long standing persistent atrial fibrillation, who had undergone mitral valve surgery and surgical removal of the left atrial appendage. Oral anticoagulation was stopped in the third month after surgery. The end-point was the absence of embolic stroke. An assessment was also made of postoperative embolism formation in the left atrium using transthoracic echocardiography. None of the patients showed embolic stroke after the third post-operative month. Only one patient exhibited transient ischaemic attack on warfarin therapy within the three postoperative months. Left atrial thrombi were also found in 11 (40.7%) cases during surgery. Of these, 6 (54.5%) had had embolic stroke, with no statistical significance (P=.703). This study suggests there might be signs that the left atrial appendage may be the main source of emboli in rheumatic mitral valve disease, and its resection could eliminate the risk of stroke in patients with rheumatic mitral valve disease and long-standing persistent atrial fibrillation. Copyright © 2016 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. All rights reserved.

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    on the relative efficacy of oral anticoagulants (OAC) and antiplatelet (AP) therapy (including acetylsalicylic acid and triflusal) on ischemic stroke, serious bleeding, and vascular events in patients with atrial fibrillation. METHODS: This is an analysis of the Atrial Fibrillation Investigators database, which...... contains patient level-data from randomized trials of stroke prevention in atrial fibrillation. We used Cox regression models with age as a continuous variable that controlled for sex, year of randomization, and history of cerebrovascular disease, diabetes, hypertension, and congestive heart failure...

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

    Science.gov (United States)

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

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

    NARCIS (Netherlands)

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

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

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

    NARCIS (Netherlands)

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

    2013-01-01

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

  17. Atrial fibrillation: non cardiologist physicians approach

    Directory of Open Access Journals (Sweden)

    Forero-Gómez, Julián Eduardo

    2017-10-01

    Full Text Available Atrial fibrillation is the most frequent arrhythmia. Its classification according to pattern and clinical type allows to decide the therapeutic strategy to use, that most include control of symptoms and prevention of cardioembolic events. The election of the treatment depends on the presence of triggering events, risk factors for thromboembolism, risk factors for bleeding, cardiac function, patient funcionality, medication costoefectiveness and health care access. The type of anticoagulant has to be supported on the type of atrial fibrillation and the presence of contraindications, documented ineffective anticoagulation or high risk of failure to warfarin. In case of contraindications for anticoagulation this could still be used in high bleeding risk patients, when risk factors are controllable or corrected; leaving left atrial appendage closure as an option for patients that remain in high risk for bleeding events.

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

    Science.gov (United States)

    Vico Besó, L; Zúñiga Cedó, E

    2013-10-01

    A case of pulmonary thromboembolism secondary to atrial myxoma right. The myxoma is a primary cardiac tumor, namely, has his origin in the cardiac tissue. Primary cardiac tumors are rare, including myxomas, the most common type. Have a predilection for females and the most useful tool for diagnosis is echocardiography. About 75% of myxomas occur in the left atrium of the heart and rest are in the right atrium. Right atrial myxomas in some sometimes associated with tricuspid stenosis and atrial fibrillation. The most common clinical manifestations include symptoms of this neoplasm constitutional, and embolic phenomena resulting from the obstruction to the flow intracavitary. The treatment of this condition is surgical. Copyright © 2012 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España. All rights reserved.

  19. Antihypertensive treatment and risk of atrial fibrillation

    DEFF Research Database (Denmark)

    Marott, Sarah C W; Nielsen, Sune F; Benn, Marianne

    2014-01-01

    AIMS: To examine the associations between antihypertensive treatment with angiotensin-converting enzyme inhibitors (ACEis) or angiotensin receptor blockers (ARBs), β-blockers, diuretics, or calcium-antagonists, and risk of atrial fibrillation. We examined these associations using the entire Danish......, and hyperthyroidism at baseline and none received any other antihypertensive medication. We studied risk of atrial fibrillation, and used risk of stroke, influenced by lowering blood pressure rather than renin-angiotensin system blockade per se, as an indicator of the importance of blood pressure lowering per se...... of stroke did not differ among the five antihypertensive medications. CONCLUSION: Use of ACEis and ARBs compared with β-blockers and diuretics associates with a reduced risk of atrial fibrillation, but not stroke, within the limitations of a retrospective study reporting associations. This suggests...

  20. Cost-effectiveness analysis of dronedarone versus other anti-arrhythmic drugs for the treatment of atrial fibrillation--results for Canada, Italy, Sweden and Switzerland.

    Science.gov (United States)

    Nilsson, Jonas; Åkerborg, Örjan; Bégo-Le Bagousse, Gaëlle; Rosenquist, Mårten; Lindgren, Peter

    2013-06-01

    The ATHENA clinical trial enrolled 4,628 patients in 37 countries and evaluated the efficacy of dronedarone 400 mg twice daily versus placebo for the prevention of cardiovascular hospitalisation or death from any cause in patients with paroxysmal or persistent atrial fibrillation or atrial flutter. The trial showed a statistically significant 24% reduction in the primary endpoint cardiovascular hospitalisations or all-cause death. In the current paper, parameters that drive the cost-effectiveness of dronedarone on top of standard therapy versus likely comparators, i.e. amiodarone, sotalol and flecainide, were investigated by means of a health economic model based on the ATHENA clinical trial. Dronedarone is cost-effective, and ICERs are low versus amiodarone with €5,340; €4,620; €3,850 and €5,630 per QALY gained for Canada, Italy, Sweden and Switzerland, respectively. The most significant driving factor for the cost-effectiveness of dronedarone is the increased survival rate for patients on dronedarone.

  1. Is the risk of atrial fibrillation higher in athletes than in the general population? A systematic review and meta-analysis

    DEFF Research Database (Denmark)

    Abdulla, Jawdat; Nielsen, Jens Rokkedal; Abdulla, Jawdat

    2009-01-01

    AIMS: The aim of this study was to examine by a systematic literature review and meta-analysis whether the risk of atrial fibrillation (AF) is higher in athletes compared with not athletes. METHODS AND RESULTS: A comprehensive systematic search was conducted for case-control studies that examined...... cases of AF or atrial flutter in athletes vs. controls. Extracted data from the eligible studies were meta-analysed using fixed effects model. Six case-control studies were eligible for meta-analysis. A total of 655 athletes and 895 controls were compared. Mean age was 51+/-9 years and 93% were men....... There were 147 (23%) vs. 116 (12.5%) cases of AF among athletes compared with controls. The overall risk of AF was significantly higher in athletes than in controls with odds ratio (95% confidence interval)=5.29 (3.57-7.85), P=0.0001, and Z-score=8.08. For heterogeneity, the calculated chi2=2.92, P=0...

  2. Rotor Design Options for Improving XV-15 Whirl-Flutter Stability Margins

    Science.gov (United States)

    Acree, C. W., Jr.; Peyran, R. J.; Johnson, Wayne

    2004-01-01

    Rotor design changes intended to improve tiltrotor whirl-flutter stability margins were analyzed. A baseline analytical model of the XV-15 was established, and then a thinner, composite wing was designed to be representative of a high-speed tiltrotor. The rotor blade design was modified to increase the stability speed margin for the thin-wing design. Small rearward offsets of the aerodynamic-center locus with respect to the blade elastic axis created large increases in the stability boundary. The effect was strongest for offsets at the outboard part of the blade, where an offset of the aerodynamic center by 10% of tip chord improved the stability margin by over 100 knots. Forward offsets of the blade center of gravity had similar but less pronounced effects. Equivalent results were seen for swept-tip blades. Appropriate combinations of sweep and pitch stiffness completely eliminated whirl flutter within the speed range examined; alternatively, they allowed large increases in pitch-flap coupling (delta-three) for a given stability margin. A limited investigation of the rotor loads in helicopter and airplane configuration showed only minor increases in loads.

  3. Reduced-Order Modeling for Flutter/LCO Using Recurrent Artificial Neural Network

    Science.gov (United States)

    Yao, Weigang; Liou, Meng-Sing

    2012-01-01

    The present study demonstrates the efficacy of a recurrent artificial neural network to provide a high fidelity time-dependent nonlinear reduced-order model (ROM) for flutter/limit-cycle oscillation (LCO) modeling. An artificial neural network is a relatively straightforward nonlinear method for modeling an input-output relationship from a set of known data, for which we use the radial basis function (RBF) with its parameters determined through a training process. The resulting RBF neural network, however, is only static and is not yet adequate for an application to problems of dynamic nature. The recurrent neural network method [1] is applied to construct a reduced order model resulting from a series of high-fidelity time-dependent data of aero-elastic simulations. Once the RBF neural network ROM is constructed properly, an accurate approximate solution can be obtained at a fraction of the cost of a full-order computation. The method derived during the study has been validated for predicting nonlinear aerodynamic forces in transonic flow and is capable of accurate flutter/LCO simulations. The obtained results indicate that the present recurrent RBF neural network is accurate and efficient for nonlinear aero-elastic system analysis

  4. Modeling the Benchmark Active Control Technology Wind-Tunnel Model for Application to Flutter Suppression

    Science.gov (United States)

    Waszak, Martin R.

    1996-01-01

    This paper describes the formulation of a model of the dynamic behavior of the Benchmark Active Controls Technology (BACT) wind-tunnel model for application to design and analysis of flutter suppression controllers. The model is formed by combining the equations of motion for the BACT wind-tunnel model with actuator models and a model of wind-tunnel turbulence. The primary focus of this paper is the development of the equations of motion from first principles using Lagrange's equations and the principle of virtual work. A numerical form of the model is generated using values for parameters obtained from both experiment and analysis. A unique aspect of the BACT wind-tunnel model is that it has upper- and lower-surface spoilers for active control. Comparisons with experimental frequency responses and other data show excellent agreement and suggest that simple coefficient-based aerodynamics are sufficient to accurately characterize the aeroelastic response of the BACT wind-tunnel model. The equations of motion developed herein have been used to assist the design and analysis of a number of flutter suppression controllers that have been successfully implemented.

  5. [Atrial myxoma: a challenge for the pneumologist].

    Science.gov (United States)

    Potre, Rodica; Ularu, D; Tudorache, V; Bertici, Nicoleta

    2003-01-01

    It presents a 59 years old woman with atypical symptoms, which orientated the diagnostic thinking during one year to a reccurrent pneumonitis, bronchial asthma, colagenosis, interstitial pulmonary fibrosis and so on. The appearance of pulmonary edema determined a couple of cardiologic exams which came to obiectivate as the main cause, the existence of a left atrial mixoma who was invaginated in left mitral cusp. Surgical intervention permitted not only specific determination of histological type of tumor, but lead to healing of the patient. It is a discussion over epidemiology, clinical areas of manifestation and methods of diagnostic of atrial tumors.

  6. Multimorbidity in Older Adults with Atrial Fibrillation.

    Science.gov (United States)

    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. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Bilateral Atrial Myxoma: A Case Report.

    Science.gov (United States)

    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.

  8. Cryoballoon Catheter Ablation in Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Cevher Ozcan

    2011-01-01

    Full Text Available Pulmonary vein isolation with catheter ablation is an effective treatment in patients with symptomatic atrial fibrillation refractory or intolerant to antiarrhythmic medications. The cryoballoon catheter was recently approved for this procedure. In this paper, the basics of cryothermal energy ablation are reviewed including its ability of creating homogenous lesion formation, minimal destruction to surrounding vasculature, preserved tissue integrity, and lower risk of thrombus formation. Also summarized here are the publications describing the clinical experience with the cryoballoon catheter ablation in both paroxysmal and persistent atrial fibrillation, its safety and efficacy, and discussions on the technical aspect of the cryoballoon ablation procedure.

  9. Whirl Flutter Stability and Its Influence on the Design of the Distributed Electric Propeller Aircraft X- 57

    Science.gov (United States)

    Hoover, Christian B.; Shen, Jinwei; Kreshock, Andrew R.; Stanford, Bret K.; Piatak, David J.; Heeg, Jennifer

    2017-01-01

    This paper studies the whirl flutter stability of the NASA experimental electric propulsion aircraft designated the X-57 Maxwell. whirl flutter stability is studied at two flight conditions: sea level at 2700 RPM to represent take-off and landing and 8000 feet at 2250 RPM to represent cruise. Two multibody dynamics analyses are used: CAMRAD II and Dymore. The CAMRAD II model is a semi-span X-57 model with a modal representation for the wing/pylon system. The Dymore model is a semi-span wing with a propeller composed of beam elements for the wing/pylon system that airloads can be applied to. The two multibody dynamics analyses were verified by comparing structural properties between each other and the NASTRAN analysis. For whirl flutter, three design revisions of the wing and pylon mount system are studied. The predicted frequencies and damping ratio of the wing modes show good agreements between the two analyses. Dymore tended to predict a slightly lower damping ratio as velocity increased for all three dynamic modes presented. Whirl flutter for the semi-span model was not present up to 500 knots for the latest design, well above the operating range of the X-57.

  10. New risk factors for atrial fibrillation : causes of 'not-so-lone atrial fibrillation'

    NARCIS (Netherlands)

    Schoonderwoerd, Bas A.; Smit, Marcelle D.; Pen, Lucas; Van Gelder, Isabelle C.

    Atrial fibrillation (AF) is a prevalent arrhythmia in patients with cardiovascular disease. The classical risk factors for developing AF include hypertension, valvular disease, (ischaemic) cardiomyopathy, diabetes mellitus, and thyroid disease. In some patients with AF, no underlying

  11. Left atrial size in patients with cryptogenic stroke as a predictor of occurrence of atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Antonio Cruz Culebras

    2017-04-01

    Full Text Available Objective: To determine whether the left atrial size can predict the development of atrial fibrillation (AF in patients with embolic stroke of undetermined source (ESUS. Methods: Patients with ischemic stroke were included prospectively (January 2015-July 2015 when ESUS was suspected. Clinical and cardiac imaging data were recorded. Patients with cardiac failure were excluded. Results: a total of 55 patients were included. Medium age was 71 years. The proportion of patients who developed AF during the follow-up (1 year was 23, 63%. 10 % of patients did not have any vascular risk factor. Basal ECG was normal in 98% of cases. The left atrial size volume was 36, 08 ml in patients who developed AF and 27, 14 ml in patients who did not. Conclusions: In patients with ESUS, left atrial size dimensions do not predict the occurrence of AF.

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

    Science.gov (United States)

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

    2014-10-01

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

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    The global burden of atrial fibrillation and diabetes mellitus (diabetes) is considerable, and prevalence rates are increasing. Diabetes is associated with an increased risk of developing atrial fibrillation; however, diabetes also influences the management and prognosis of atrial fibrillation...... and outcomes of heart failure and the success rates of both ablation and cardioversion in atrial fibrillation patients with diabetes. Finally, this article describes the association of HbA1c levels with the management and prognosis of atrial fibrillation patients........ In the following article, the authors describe the association between diabetes and atrial fibrillation; specifically, the significance of diabetes on the risk of atrial fibrillation, ischemic stroke and bleeding complications associated with anticoagulation. In addition, the authors evaluate the risks...

  14. Right atrial mass following transcatheter radiofrequency ablation for recurrent atrial fibrillation: thrombus, endocarditis or mixoma?

    Science.gov (United States)

    Ancona, Roberta; Comenale Pinto, Salvatore; Caso, Pio; Di Palma, Vito; Pisacane, Francesca; Martiniello, Alfonso Roberto; Quarto, Cesare; De Rosa, Nicla; Pisacane, Carlo; Calabrò, Raffaele

    2009-03-01

    We report a case of an asymptomatic patient in whom a right atrial mass was fortuitously documented by echocardiography few months after a transcatheter radiofrequency catheter ablation for recurrent AF. No masses were seen in the cardiac chambers before the ablative procedure, raising important diagnostic and decision-making issues. The patient was referred to the surgeon and a diagnosis of right atrial myxoma was made.

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

    Directory of Open Access Journals (Sweden)

    Ha Eun Kim

    2016-06-01

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

  16. Left atrial appendage closure devices for cardiovascular risk reduction in atrial fibrillation patients

    Directory of Open Access Journals (Sweden)

    Cruz-Gonzalez I

    2015-05-01

    Full Text Available Ignacio Cruz-Gonzalez,* Juan Carlos Rama-Merchan,* Javier Rodriguez-Collado, Javier Martin-Moreiras, Alejandro Diego-Nieto, Antonio Arribas-Jimenez, Pedro Luís SanchezDepartment of Cardiology, University Hospital of Cardiology and IBSAL, Salamanca, Spain *Ignacio Cruz-Gonzalez and Juan Carlos Rama-Merchan have contributed equally to this work and should be considered co-first authors Abstract: Atrial fibrillation (AF is the most common sustained arrhythmia in clinical practice. AF is associated with a 4–5-fold increased risk of stroke and systemic embolism. Oral anticoagulant is the first-line therapy for this purpose, but it has various limitations and is often contraindicated or underutilized. Autopsy and surgical data have suggested that 90% of atrial thrombi in nonvalvular AF patients originate from the left atrial appendage, leading to the development of percutaneous closure for thromboembolic prevention. This paper examines the current evidence on left atrial appendage closure devices for cardiovascular risk reduction in AF patients. Keywords: atrial fibrillation, left atrial appendage, stroke, oral anticoagulant, percutaneous closure, thromboembolic prevention

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

    Directory of Open Access Journals (Sweden)

    Ashok J. Shah

    2010-01-01

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

  18. ANTIARRHYTMIC EFFICACY OF SOTALOL IN PATIENTS WITH TACHY-BRADY SYNDROME HAVING ATRIAL PACEMAKER WITH DIFFERENT ATRIAL ELECTRODE POSITION

    Directory of Open Access Journals (Sweden)

    T. N. Novikova

    2009-01-01

    Full Text Available Aim. To evaluate efficacy of the combined therapy (sotalol and constant electric cardiostimulation in AAI regimen at two atrial electrode position: in low back part of interatrial septum (IAS and in right atrial auricle (RAA.Material and methods. 20 patients with tachy-brady syndrome were examined. They were randomized in 2 groups depending on atrial electrode position. Sotalol (160 mg daily was prescribed to all patients in a month after implantation of constant atrial pacemaker (CAP. A number of atrial fibrillation paroxysms (AFP was evaluated initially, in a month after CAP implantation and in a month after start of sotalol therapy.Results. Significant AFP reduction was observed in IAS stimulation, unlike RAA stimulation. Sotalol addition had essential significance in the termination or reduction of AFP. Sotalol effect did not depend on atrial electrode position.Conclusion. Sotalol usage together with constant electric cardiostimulation significantly reduces AFP irrespectively of atrial electrode position. 

  19. Left atrial catheter ablation and ischemic stroke.

    Science.gov (United States)

    Haeusler, Karl Georg; Kirchhof, Paulus; Endres, Matthias

    2012-01-01

    Left atrial catheter ablation (LACA) has become an established therapy to abolish drug-refractory symptomatic paroxysmal and persistent atrial fibrillation. Restoring sinus rhythm by LACA may help to prevent atrial fibrillation-related strokes, but presently there is no evidence from randomized clinical trials to support this notion. This review summarizes the current knowledge and uncertainties regarding LACA and procedure-related ischemic stroke. In fact, most patients who undergo LACA have a rather low annual stroke risk even when left untreated, whereas LACA imposes a risk of procedure-related stroke of ≈0.5% to 1%. In addition, LACA may cause cerebral microemboli, resulting in ischemic lesions. These cerebral lesions, detectable by high-resolution MRI, could contribute to neuropsychological deficits and cognitive dysfunction. Furthermore, recurrent atrial fibrillaton episodes can be detected up to years after LACA and might cause ischemic strokes, especially in those patients in whom therapeutic anticoagulation was discontinued. Further prospective multicenter trials are needed to identify procedure-dependent risk factors for stroke and to optimize postprocedural anticoagulation management.

  20. Left atrial myxoma with biventricular dysfunction.

    Science.gov (United States)

    Raut, Monish S; Shad, Sujay; Maheshwari, Arun

    2016-09-01

    Occurrence of left atrial myxoma with severe ventricular dysfunction without any obstructive coronary artery disease, as presented in our case, is very rare. It may be due to undiagnosed concomitant dilated cardiomyopathy or unknown cardiodepressant effect of myxoma which warrants further research. Copyright © 2016 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

  1. Endometrial Adenocarcinoma with Concomitant Left Atrial Myxoma

    Directory of Open Access Journals (Sweden)

    Lisa N. Abaid

    2009-08-01

    Full Text Available Background: Atrial myxomas are the most common primary heart tumors and predominantly considered to be benign lesions. Case Study: We report a case involving a 77-year-old woman who presented with a pelvic mass. She was found to have a primary endometrial cancer and primary lung cancer with concomitant metastatic adrenal gland and mesenteric lesions. Her prior medical history also included an untreated 4.0 × 2.0-cm left atrial myxoma which was identified on CT scan during the workup of her pelvic mass. Results: A clinical decision was made to proceed with surgery for the pelvic mass with a subsequent recommendation for left atrial mass resection. Currently, the patient is scheduled to begin chemotherapy for primary lung cancer. Conclusion: The reported incidence of uterine cancer and a concurrent atrial myxoma is very rare. Consequently, the manner and timing in which treatment should be provided is imprecise. In the present case, the risk for cardiac complications was high, but given the presence of a partial bowel obstruction and the need to diagnose the primary site of her metastatic malignancy, the decision was made to proceed with exploratory abdominal surgery.

  2. Genetic aspects of lone atrial fibrillation

    DEFF Research Database (Denmark)

    Andreasen, Laura; Nielsen, Jonas B; Olesen, Morten S

    2015-01-01

    Atrial fibrillation (AF) is the most common cardiac arrhythmia. A subgroup of patients presents with AF without traditional risk factors and is diagnosed before the age of 60 years. Such patients are commonly referred as having "lone AF" and comprise 10-20% of all cases. A number of studies have ...

  3. Genetic Risk Prediction of Atrial Fibrillation

    NARCIS (Netherlands)

    Lubitz, Steven A; Yin, Xiaoyan; Lin, Henry; Kolek, Matthew; Smith, J Gustav; Trompet, Stella; Rienstra, Michiel; Rost, Natalia S; Teixeira, Pedro; Almgren, Peter; Anderson, Christopher D; Chen, Lin Y; Engström, Gunnar; Ford, Ian; Furie, Karen L; Guo, Xiuqing; Larson, Martin G; Lunetta, Kathryn; Macfarlane, Peter W; Psaty, Bruce M; Soliman, Elsayed Z; Sotoodehnia, Nona; Stott, David J; Taylor, Kent D; Weng, Lu-Chen; Yao, Jie; Geelhoed, Bastiaan; Verweij, Niek; Siland, Joylene E; Kathiresan, Sekar; Roselli, Carolina; Roden, Dan M; van der Harst, Pim; Darbar, Dawood; Jukema, J Wouter; Melander, Olle; Rosand, Jonathan; Rotter, Jerome I; Heckbert, Susan R; Ellinor, Patrick T; Alonso, Alvaro; Benjamin, Emelia J

    2017-01-01

    BACKGROUND: Atrial fibrillation (AF) has a substantial genetic basis. Identification of individuals at greatest AF risk could minimize the incidence of cardioembolic stroke. METHODS: To determine whether genetic data can stratify risk for development of AF, we examined associations between AF

  4. Risk of atrial fibrillation in diabetes mellitus

    DEFF Research Database (Denmark)

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

    2016-01-01

    .81-8.98) and 20.0 (19.9-20.2) in the background population and 0.13 (0.09-0.20), 2.10 (2.00-2.20), 8.41 (8.10-8.74) and 20.1 (19.4-20.8) in the diabetes group, respectively. The adjusted incidence rate ratios in the diabetes group with the background population as reference were 2.34 (1.52-3.60), 1.52 (1......AIM: Diabetes has been associated with atrial fibrillation but the current evidence is conflicting. In particular knowledge regarding young diabetes patients and the risk of developing atrial fibrillation is sparse. The aim of our study was to investigate the risk of atrial fibrillation in patients...... with diabetes compared to the background population in Denmark. METHODS AND RESULTS: Through Danish nationwide registries we included persons above 18 years of age and without prior atrial fibrillation and/or diabetes from 1996 to 2012. The study cohort was divided into a background population without diabetes...

  5. Long-term outcome of healthy participants with atrial premature complex: a 15-year follow-up of the NIPPON DATA 90 cohort.

    Directory of Open Access Journals (Sweden)

    Taku Inohara

    Full Text Available BACKGROUND: Atrial premature complexes (APC are among the most frequently encountered electrocardiographic abnormalities. However, their prognostic value among healthy individuals is unclear. This study aimed to clarify the role of APC in predicting cardiovascular events in a large Japanese community cohort using long-term follow-up data. METHODS: National Integrated Project for Prospective Observation of Non-communicable Disease And its Trends in the Aged, 1990-2005, (NIPPON DATA 90 was a large cohort study of cardiovascular disease (CVD in Japan. A total of 7692 otherwise healthy participants with no history of myocardial infarction, stroke, atrial fibrillation, or atrial flutter were enrolled (men, 41.5%; mean age, 52.5 ± 13.7 years. RESULTS: A total of 64 (0.8% participants had at least one beat of APC on screening 12-lead electrocardiogram. During the follow-up of 14.0 ± 2.9 years (total, 107,474 patient-years, 338 deaths occurred due to CVD. The association between APC and CVD outcome was assessed using Cox proportional hazard models. Cox regression analysis revealed that the presence of APC was an independent predictor for CVD deaths (HR: 2.03, 95% CI: 1.12-3.66, P = 0.019. The association of APC on CVD death was more evident in participants with hypertension (P-value for interaction, 0.03. CONCLUSIONS: APC recorded during the screening electrocardiogram are significantly associated with an increased risk of CVD deaths in a Japanese community-dwelling population and are a strong prognostic factor for hypertensive participants.

  6. Increased mortality associated with digoxin in contemporary patients with atrial fibrillation: findings from the TREAT-AF study.

    Science.gov (United States)

    Turakhia, Mintu P; Santangeli, Pasquale; Winkelmayer, Wolfgang C; Xu, Xiangyan; Ullal, Aditya J; Than, Claire T; Schmitt, Susan; Holmes, Tyson H; Frayne, Susan M; Phibbs, Ciaran S; Yang, Felix; Hoang, Donald D; Ho, P Michael; Heidenreich, Paul A

    2014-08-19

    Despite endorsement of digoxin in clinical practice guidelines, there exist limited data on its safety in atrial fibrillation/flutter (AF). The goal of this study was to evaluate the association of digoxin with mortality in AF. Using complete data of the TREAT-AF (The Retrospective Evaluation and Assessment of Therapies in AF) study from the U.S. Department of Veterans Affairs (VA) healthcare system, we identified patients with newly diagnosed, nonvalvular AF seen within 90 days in an outpatient setting between VA fiscal years 2004 and 2008. We used multivariate and propensity-matched Cox proportional hazards to evaluate the association of digoxin use with death. Residual confounding was assessed by sensitivity analysis. Of 122,465 patients with 353,168 person-years of follow-up (age 72.1 ± 10.3 years, 98.4% male), 28,679 (23.4%) patients received digoxin. Cumulative mortality rates were higher for digoxin-treated patients than for untreated patients (95 vs. 67 per 1,000 person-years; p death was not modified by age, sex, heart failure, kidney function, or concomitant use of beta-blockers, amiodarone, or warfarin. Digoxin was associated with increased risk of death in patients with newly diagnosed AF, independent of drug adherence, kidney function, cardiovascular comorbidities, and concomitant therapies. These findings challenge current cardiovascular society recommendations on use of digoxin in AF. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  7. Amiodarone and Risk of Death in Contemporary Patients with Atrial Fibrillation: Findings from the TREAT-AF Study

    Science.gov (United States)

    Ullal, Aditya J.; Than, Claire T.; Fan, Jun; Schmitt, Susan; Perino, Alexander C.; Kaiser, Daniel W.; Heidenreich, Paul A.; Frayne, Susan M.; Phibbs, Ciaran S.; Turakhia, Mintu P.

    2016-01-01

    Background There are limited data on mortality outcomes associated with use of amiodarone in atrial fibrillation and flutter (AF). Methods We evaluated the association of amiodarone use with mortality in patients with newly-diagnosed AF using complete data from the Department of Veterans Affairs (VA) national health care system. We included patients seen in an outpatient setting within 90 days of a new diagnosis for non-valvular AF between VA fiscal years 2004–2008. Multivariate and propensity-matched Cox proportional hazards were used to evaluate the association of amiodarone use to death. Results Of 122,465 patients (353,168 person-years of follow-up; age 72.1±10.3 years; 98.4% males), amiodarone was prescribed in 11,655 (9.5%). Cumulative, unadjusted mortality rates were higher for amiodarone recipients than for non-recipients (87 vs. 73 per 1000 person-years, Pdeath was not modified by age, sex, heart failure, kidney function, beta blocker use, or warfarin use but there was evidence of effect modification among patients diagnosed with AF as an inpatient versus outpatient. Conclusion In a national health care system population of newly-diagnosed AF, overall use of amiodarone as an early treatment strategy was not associated with mortality. PMID:26542514

  8. Stroke as the First Manifestation of Atrial Fibrillation.

    Science.gov (United States)

    Jaakkola, Jussi; Mustonen, Pirjo; Kiviniemi, Tuomas; Hartikainen, Juha E K; Palomäki, Antti; Hartikainen, Päivi; Nuotio, Ilpo; Ylitalo, Antti; Airaksinen, K E Juhani

    2016-01-01

    Atrial fibrillation may remain undiagnosed until an ischemic stroke occurs. In this retrospective cohort study we assessed the prevalence of ischemic stroke or transient ischemic attack as the first manifestation of atrial fibrillation in 3,623 patients treated for their first ever stroke or transient ischemic attack during 2003-2012. Two groups were formed: patients with a history of atrial fibrillation and patients with new atrial fibrillation diagnosed during hospitalization for stroke or transient ischemic attack. A control group of 781 patients with intracranial hemorrhage was compiled similarly to explore causality between new atrial fibrillation and stroke. The median age of the patients was 78.3 [13.0] years and 2,009 (55.5%) were women. New atrial fibrillation was diagnosed in 753 (20.8%) patients with stroke or transient ischemic attack, compared to 15 (1.9%) with intracranial hemorrhage. Younger age and no history of coronary artery disease or other vascular diseases, heart failure, or hypertension were the independent predictors of new atrial fibrillation detected concomitantly with an ischemic event. Thus, ischemic stroke was the first clinical manifestation of atrial fibrillation in 37% of younger (<75 years) patients with no history of cardiovascular diseases. In conclusion, atrial fibrillation is too often diagnosed only after an ischemic stroke has occurred, especially in middle-aged healthy individuals. New atrial fibrillation seems to be predominantly the cause of the ischemic stroke and not triggered by the acute cerebrovascular event.

  9. Hybrid ablation for atrial fibrillation: current approaches and future directions.

    Science.gov (United States)

    Bisleri, Gianluigi; Glover, Benedict

    2017-01-01

    Catheter ablation of atrial fibrillation has rapidly evolved during the past decade: although the treatment of paroxysmal atrial fibrillation via a transcatheter approach has been consistently successful, persistent and long-standing atrial fibrillation still represents a major clinical challenge with less favorable outcomes to date. Because novel, minimally invasive surgical approaches have been developed for atrial fibrillation ablation, the aim of the present review is to analyze the current evidence surrounding the integration of surgical and transcatheter strategies in a hybrid fashion for the treatment of atrial fibrillation. Long-standing persistent, atrial fibrillation requires further understanding. Wide antral circumferential ablation of the pulmonary veins represents the cornerstone of any ablation therapy. Additional linear lesions and/or targeting complex fractionated atrial electrograms may also be considered. One of the limitations is achieving a transmural lesion. The combined endocardial and epicardial approach may represent a superior approach. Hybrid ablation of atrial fibrillation represents a novel therapeutic strategy for the treatment of complex scenarios, such as long-standing persistent atrial fibrillation. A specialized team including dedicated surgeons and cardiologists appears to be crucial in order to achieve durable and satisfactory outcomes following hybrid ablation of atrial fibrillation.

  10. Increased risk of heart failure and atrial fibrillation in heterozygous familial hypercholesterolemia.

    Science.gov (United States)

    Hovland, Anders; Mundal, Liv J; Igland, Jannicke; Veierød, Marit B; Holven, Kirsten B; Bogsrud, Martin P; Tell, Grethe S; Leren, Trond P; Retterstøl, Kjetil

    2017-11-01

    Heart failure (HF) and atrial fibrillation/flutter (AF) are important causes of morbidity and mortality. Subjects with familial hypercholesterolemia (FH) carry a high risk of coronary artery disease (CAD) but it is not known if the risk of HF and AF is increased in FH. The present study investigated the incidence of hospitalization for HF and AF in a genetically verified FH cohort, age 25 years and older, compared to the general population. Incidence rates of hospitalization for HF and AF were estimated from national registry data. Standardized incidence ratios (SIRs) were calculated. 4273 genotyped FH patients (51.7% women) with a total observation period of 18,300 patient years were studied. Overall, the expected number of FH patients with HF was 27.7 and the observed number of cases was 54 (SIR (95% CI) 2.0 (1.5-2.6)). The highest excess risk was observed in the age group 25-49 years, where SIRs were 3.8 (1.2-11.8) and 4.2 (2.0-8.8) in women and men, respectively. The total expected number of FH patients with AF was 39.4 while the observed number of cases was 77 (SIR 2.0 (1.6-2.4)). Among FH patients with an incident event of HF, nearly 90% had a previous diagnosis of CAD, and nearly 40% had suffered from a myocardial infarction. We demonstrate a doubling of the risk of hospitalization for HF or AF in patients with FH. This is could have an important prognostic impact for patients and economic impact for the society. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. A Cross-Validation Approach to Approximate Basis Function Selection of the Stall Flutter Response of a Rectangular Wing in a Wind Tunnel

    Science.gov (United States)

    Kukreja, Sunil L.; Vio, Gareth A.; Andrianne, Thomas; azak, Norizham Abudl; Dimitriadis, Grigorios

    2012-01-01

    The stall flutter response of a rectangular wing in a low speed wind tunnel is modelled using a nonlinear difference equation description. Static and dynamic tests are used to select a suitable model structure and basis function. Bifurcation criteria such as the Hopf condition and vibration amplitude variation with airspeed were used to ensure the model was representative of experimentally measured stall flutter phenomena. Dynamic test data were used to estimate model parameters and estimate an approximate basis function.

  12. Bending-torsional flutter of a cantilevered pipe conveying fluid with an inclined terminal nozzle

    Science.gov (United States)

    Firouz-Abadi, R. D.; Askarian, A. R.; Kheiri, M.

    2013-06-01

    Stability analysis of a horizontal cantilevered pipe conveying fluid with an inclined terminal nozzle is considered in this paper. The pipe is modelled as a cantilevered Euler-Bernoulli beam, and the flow-induced inertia, Coriolis and centrifugal forces along the pipe as well as the follower force induced by the jet-flow are taken into account. The governing equations of the coupled bending-torsional vibrations of the pipe are obtained using extended Hamilton's principle and are then discretized via the Galerkin method. The resulting eigenvalue problem is then solved, and several cases are examined to determine the effect of nozzle inclination angle, nozzle aspect ratio, mass ratio and bending-to-torsional rigidity ratio on flutter speed of the system.

  13. Scalability of the parallel CFD simulations of flow past a fluttering airfoil in OpenFOAM

    Directory of Open Access Journals (Sweden)

    Šidlof Petr

    2015-01-01

    Full Text Available The paper is devoted to investigation of unsteady subsonic airflow past an elastically supported airfoil during onset of the flutter instability. Based on the geometry, boundary conditions and airfoil motion data identified from wind-tunnel measurements, a 3D CFD model has been set up in OpenFOAM. The model is based on incompressible Navier-Stokes equations. The turbulence is modelled by the Menter’s k-omega shear stress transport turbulence model. The computational mesh was generated in GridPro, a mesh generator capable of producing highly orthogonal structured C-type meshes. The mesh totals 3.1 million elements. Parallel scalability was measured on a small shared-memory SGI Altix UV 100 supercomputer.

  14. Episodic syncope caused by ventricular flutter in a tiger (Panthera tigris).

    Science.gov (United States)

    DeLillo, Daniel M; Jesty, Sophy A; Souza, Marcy J

    2013-06-01

    A captive, 9-yr-old castrated male tiger (Panthera tigris) from an exotic cat sanctuary and rescue facility was observed to have three collapsing episodes within a 2-wk interval prior to being examined by veterinarians. No improvement in clinical signs was noted after empiric treatment with phenobarbital. During a more complete workup for epilepsy, ventricular flutter was observed on electrocardiogram (ECG). The arrhythmia resolved with a single intravenous bolus of lidocaine. Cardiac structure and function were unremarkable on echocardiogram and cardiac troponin I levels were within normal limits for domestic felids. No significant abnormalities were noted on abdominal ultrasound. Complete blood count and biochemistry panel were unremarkable, and heartworm antigen and Blastomyces urine antigen enzyme-linked immunosorbent assays were negative. Antiarrhythmic treatment with sotalol was initiated. On follow-up ECG performed 1 mo later, no significant arrhythmias were noted, and clinical signs have completely resolved.

  15. Scalability of the parallel CFD simulations of flow past a fluttering airfoil in OpenFOAM

    Science.gov (United States)

    Šidlof, Petr; Řidký, Václav

    2015-05-01

    The paper is devoted to investigation of unsteady subsonic airflow past an elastically supported airfoil during onset of the flutter instability. Based on the geometry, boundary conditions and airfoil motion data identified from wind-tunnel measurements, a 3D CFD model has been set up in OpenFOAM. The model is based on incompressible Navier-Stokes equations. The turbulence is modelled by the Menter's k-omega shear stress transport turbulence model. The computational mesh was generated in GridPro, a mesh generator capable of producing highly orthogonal structured C-type meshes. The mesh totals 3.1 million elements. Parallel scalability was measured on a small shared-memory SGI Altix UV 100 supercomputer.

  16. Use of the Matching Pursuit Algorithm for Flight Flutter Test Data Analysis

    Science.gov (United States)

    Nelson, Ronald E.; Brenner, Martin

    1996-01-01

    The goal of flight flutter testing is to detect possibly destructive modes of aircraft vibration which may arise during flight from interaction of aerodynamic forces with structural dynamic properties of the airframe. This is typically accomplished by exciting the airframe with a time varying force and monitoring the response of the aircraft throughout its flight envelope. The data generated must be analyzed and presented so that the frequency and time of occurrence of excited modes are clearly and unambiguously displayed. Processing and display in near real time is also desirable. Display of data in the time-frequency plane is a natural choice because it is a familiar and intuitive framework. The Matching Pursuit algorithm provides a time-frequency analysis with good adaptability to signal structure and good signal representation in the time-frequency plane. Improvements in efficiency are needed before the algorithm can be used in real time, however.

  17. Parallel numerical simulation of oscillating airfoil NACA0015 in the channel due to flutter instability

    Directory of Open Access Journals (Sweden)

    Řidký Václav

    2014-03-01

    Full Text Available The work is devoted to 3D and 2D parallel numerical computation of pressure and velocity fields around an elastically supported airfoil self-oscillating due to interaction with the airflow. Numerical solution is computed in the OpenFOAM package, an open-source software package based on finite volume method. Movement of airfoil is described by translation and rotation, identified from experimental data. A new boundary condition for the 2DOF motion of the airfoil was implemented. The results of numerical simulations (velocity are compared with data measured in a wind tunnel, where a physical model of NACA0015 airfoil was mounted and tuned to exhibit the flutter instability. The experimental results were obtained previously in the Institute of Thermomechanics by interferographic measurements in a subsonic wind tunnel in Nový Knín.

  18. Effects of Swept Tips on V-22 Whirl Flutter and Loads

    Science.gov (United States)

    Acree, C. W., Jr.

    2005-01-01

    A CAMRAD II model of the V-22 Osprey tiltrotor was constructed for the purpose of analyzing the effects of blade design changes on whirl flutter. The model incorporated a dual load-path grip/yoke assembly, a swashplate coupled to the transmission case, and a drive train. A multiple-trailer free wake was used for loads calculations. The effects of rotor design changes on whirl-mode stability were calculated for swept blades and offset tip masses. A rotor with swept tips and inboard tuning masses was examined in detail to reveal the mechanisms by which these design changes affect stability and loads. Certain combinations of design features greatly increased whirl-mode stability, with (at worst) moderate increases to loads.

  19. Effects of Blade Sweep on V-22 Whirl Flutter and Loads

    Science.gov (United States)

    Acree, C. W., Jr.

    2003-01-01

    A CAMRAD II model of the V-22 Osprey tiltrotor was constructed for the purpose of analyzing the effects of blade design changes on whirl flutter. The model incorporated a dual load-path griplyoke assembly, a swashplate coupled to the transmission, and a drive train. A multiple-trailer free wake was used for loads calculations. The effects of rotor design changes on whirl-mode stability were calculated for swept blades and offset tip masses. A rotor with swept tips and inboard tuning masses was examined in detail to reveal the mechanisms by which these design changes affect stability and loads. Certain combinations of design features greatly increased whirl-mode stability, with (at worst) moderate increases to loads.

  20. Effects of V-22 Blade Modifications on Whirl Flutter and Loads

    Science.gov (United States)

    Acree, C. W., Jr.

    2004-01-01

    A CAMRAD II model of the V-22 Osprey tiltrotor was constructed for the purpose of analyzing the effects of blade design changes on whirl flutter. The model incorporated a dual load-path grip/yoke assembly, a swashplate coupled to the transmission case, and a drive train. A multiple-trailer free wake was used for loads calculations. The effects of rotor design changes on whirl-mode stability were calculated for swept blades and offset tip masses. A rotor with swept tips and inboard tuning masses was examined in detail to reveal the mechanisms by which these design changes affect stability and loads. Certain combinations of design features greatly increased whirl-mode stability, with (at worst) moderate increases to loads.

  1. NACA0012 benchmark model experimental flutter results with unsteady pressure distributions

    Science.gov (United States)

    Rivera, Jose A., Jr.; Dansberry, Bryan E.; Bennett, Robert M.; Durham, Michael H.; Silva, Walter A.

    1992-01-01

    The Structural Dynamics Division at NASA Langley Research Center has started a wind tunnel activity referred to as the Benchmark Models Program. The primary objective of this program is to acquire measured dynamic instability and corresponding pressure data that will be useful for developing and evaluating aeroelastic type computational fluid dynamics codes currently in use or under development. The program is a multi-year activity that will involve testing of several different models to investigate various aeroelastic phenomena. This paper describes results obtained from a second wind tunnel test of the first model in the Benchmark Models Program. This first model consisted of a rigid semispan wing having a rectangular planform and a NACA 0012 airfoil shape which was mounted on a flexible two degree of freedom mount system. Experimental flutter boundaries and corresponding unsteady pressure distribution data acquired over two model chords located at the 60 and 95 percent span stations are presented.

  2. Could successful cryoballoon ablation of paroxysmal atrial fibrillation prevent progressive left atrial remodeling?

    Science.gov (United States)

    Erdei, Tamás; Dénes, Mónika; Kardos, Attila; Mihálcz, Attila; Földesi, Csaba; Temesvári, András; Lengyel, Mária

    2012-03-19

    Radiofrequency catheter ablation of atrial fibrillation (AF) has been proved to be effective and to prevent progressive left atrial (LA) remodeling. Cryoballoon catheter ablation (CCA), using a different energy source, was developed to simplify the ablation procedure. Our hypothesis was that successful CCA can also prevent progressive LA remodeling. 36 patients selected for their first CCA because of nonvalvular paroxysmal AF had echocardiography before and 3, 6 and 12 months after CCA. LA diameters, volumes (LAV) and LA volume index (LAVI) were evaluated. LA function was assessed by: early diastolic velocities of the mitral annulus (Aa(sept), Aa(lat)), LA filling fraction (LAFF), LA emptying fraction (LAEF) and the systolic fraction of pulmonary venous flow (PVSF). Detailed left ventricular diastolic function assessment was also performed. Excluding recurrences in the first 3-month blanking period, the clinical success rate was 64%. During one-year of follow-up, recurrent atrial arrhythmia was found in 21 patients (58%). In the recurrent group at 12 months after ablation, minimal LAV (38 ± 19 to 44 ± 20 ml; p < 0.05), maximal LAV (73 ± 23 to 81 ± 24 ml; p < 0.05), LAVI (35 ± 10 to 39 ± 11 ml/m2; p = 0.01) and the maximal LA longitudinal diameter (55 ± 5 to 59 ± 6 mm; p < 0.01) had all increased. PVSF (58 ± 9 to 50 ± 10%; p = 0.01) and LAFF (36 ± 7 to 33 ± 8%; p = 0.03) had decreased. In contrast, after successful cryoballoon ablation LA size had not increased and LA function had not declined. In the recurrent group LAEF was significantly lower at baseline and at follow-up visits. In patients whose paroxysmal atrial fibrillation recurred within one year after cryoballoon catheter ablation left atrial size had increased and left atrial function had declined. In contrast, successful cryoballoon catheter ablation prevented progressive left atrial remodeling.

  3. Could successful cryoballoon ablation of paroxysmal atrial fibrillation prevent progressive left atrial remodeling?

    Directory of Open Access Journals (Sweden)

    Erdei Tamás

    2012-03-01

    Full Text Available Abstract Background Radiofrequency catheter ablation of atrial fibrillation (AF has been proved to be effective and to prevent progressive left atrial (LA remodeling. Cryoballoon catheter ablation (CCA, using a different energy source, was developed to simplify the ablation procedure. Our hypothesis was that successful CCA can also prevent progressive LA remodeling. Methods 36 patients selected for their first CCA because of nonvalvular paroxysmal AF had echocardiography before and 3, 6 and 12 months after CCA. LA diameters, volumes (LAV and LA volume index (LAVI were evaluated. LA function was assessed by: early diastolic velocities of the mitral annulus (Aasept, Aalat, LA filling fraction (LAFF, LA emptying fraction (LAEF and the systolic fraction of pulmonary venous flow (PVSF. Detailed left ventricular diastolic function assessment was also performed. Results Excluding recurrences in the first 3-month blanking period, the clinical success rate was 64%. During one-year of follow-up, recurrent atrial arrhythmia was found in 21 patients (58%. In the recurrent group at 12 months after ablation, minimal LAV (38 ± 19 to 44 ± 20 ml; p p 2; p = 0.01 and the maximal LA longitudinal diameter (55 ± 5 to 59 ± 6 mm; p p = 0.01 and LAFF (36 ± 7 to 33 ± 8%; p = 0.03 had decreased. In contrast, after successful cryoballoon ablation LA size had not increased and LA function had not declined. In the recurrent group LAEF was significantly lower at baseline and at follow-up visits. Conclusions In patients whose paroxysmal atrial fibrillation recurred within one year after cryoballoon catheter ablation left atrial size had increased and left atrial function had declined. In contrast, successful cryoballoon catheter ablation prevented progressive left atrial remodeling.

  4. Sustained Spatial Attention to Vibrotactile Stimulation in the Flutter Range: Relevant Brain Regions and Their Interaction

    Science.gov (United States)

    Goltz, Dominique; Pleger, Burkhard; Thiel, Sabrina; Villringer, Arno; Müller, Matthias M.

    2013-01-01

    The present functional magnetic resonance imaging (fMRI) study was designed to get a better understanding of the brain regions involved in sustained spatial attention to tactile events and to ascertain to what extent their activation was correlated. We presented continuous 20 Hz vibrotactile stimuli (range of flutter) concurrently to the left and right index fingers of healthy human volunteers. An arrow cue instructed subjects in a trial-by-trial fashion to attend to the left or right index finger and to detect rare target events that were embedded in the vibrotactile stimulation streams. We found blood oxygen level-dependent (BOLD) attentional modulation in primary somatosensory cortex (SI), mainly covering Brodmann area 1, 2, and 3b, as well as in secondary somatosensory cortex (SII), contralateral to the to-be-attended hand. Furthermore, attention to the right (dominant) hand resulted in additional BOLD modulation in left posterior insula. All of the effects were caused by an increased activation when attention was paid to the contralateral hand, except for the effects in left SI and insula. In left SI, the effect was related to a mixture of both a slight increase in activation when attention was paid to the contralateral hand as well as a slight decrease in activation when attention was paid to the ipsilateral hand (i.e., the tactile distraction condition). In contrast, the effect in left posterior insula was exclusively driven by a relative decrease in activation in the tactile distraction condition, which points to an active inhibition when tactile information is irrelevant. Finally, correlation analyses indicate a linear relationship between attention effects in intrahemispheric somatosensory cortices, since attentional modulation in SI and SII were interrelated within one hemisphere but not across hemispheres. All in all, our results provide a basis for future research on sustained attention to continuous vibrotactile stimulation in the range of flutter

  5. SUSTAINED ATRIAL-FLUTTER AROUND THE TRICUSPID-VALVE IN PIGS - DIFFERENTIATION OF PROCAINAMIDE (CLASS-IA) FROM FLECAINIDE (CLASS-IC) AND THEIR RATE-DEPENDENT EFFECTS

    NARCIS (Netherlands)

    CRIJNS, HJGM; DELANGEN, CDJ; GRANDJEAN, JG; BEL, KJ; EBELS, T; LIE, KI; WESSELING, H

    The wavelength theory considers two determinants of reentry, i.e., refractoriness and conduction velocity. It does not take excitability into account primarily. We evaluated frequency-dependence of excitability and refractoriness before and after flecainide or procainamide administration in relation

  6. Atrial septal defects in Florida panthers.

    Science.gov (United States)

    Cunningham, M W; Dunbar, M R; Buergelt, C D; Homer, B L; Roelke-Parker, M E; Taylor, S K; King, R; Citino, S B; Glass, C

    1999-07-01

    Ostium secundum atrial septal defects (ASDs) were observed in six (3 M, 3 F) of 33 (20 M, 13 F) (18%) Florida panthers (Puma concolor coryi) necropsied by veterinary pathologists between 1985 and 1998. A seventh ASD was found in a female panther necropsied in the field and is included in the pathological description but not the prevalence of ASDs in Florida panthers. One panther (FP205) with severe ASD also had tricuspid valve dysplasia (TVD). Atrial septal defects and/or TVD are believed to have caused or contributed to the deaths of three (9%) Florida panthers in this study. Mean diameter +/- SD of ASDs was 9.0 +/- 4.7 mm (range 3 to 15 mm). Gross pathological changes attributed to ASDs/TVD in severely affected panthers (ASD > or = 10 mm) (n = 4) included mild right ventricular dilatation (n = 3) and hypertrophy (n = 2), mild to severe right atrial dilatation (n = 2), and acute pulmonary edema (n = 3). Panthers with mild ASDs (ASD < or = 5 mm) (n = 3) had no other detectable gross pathological changes associated with the ASDs. Histological examination of lungs of three panthers with severe ASDs revealed mild to moderate dilatation with fibrosis and smooth muscle atrophy of the tunica media of medium to large caliber arteries (n = 2), interstitial and/or pleural fibrosis (n = 2), perivascular fibrosis (n = 1), and acute to chronic edema (n = 3). Twenty-six necropsied panthers were examined one or more times while living; medical records were retrospectively evaluated. Antemortem radiographic, electrocardiographic, and echocardiographic examinations were performed on two panthers with severe ASDs (FP20 and FP205). Thoracic radiographic abnormalities in both included right heart enlargement, and in FP205 (severe ASD and TVD), mild pulmonary overperfusion. Electrocardiographic examination of FP205 revealed a right ventricular hypertrophy pattern, while FP205 had a normal electrocardiogram. Echocardiographic examination of FP20 revealed marked right atrial dilatation

  7. Atrial myxoma in a patient with hypertrophic cardiomyopathy.

    Science.gov (United States)

    Abdou, Mahmoud; Hayek, Salim; Williams, Byron R

    2013-01-01

    Atrial myxoma is the most common primary cardiac tumor. Patients with atrial myxoma typically present with obstructive, embolic, or systemic symptoms; asymptomatic presentation is very rare. To our knowledge, isolated association of atrial myxoma with hypertrophic cardiomyopathy has been reported only once in the English-language medical literature. We report the case of an asymptomatic 71-year-old woman with known hypertrophic cardiomyopathy in whom a left atrial mass was incidentally identified on cardiac magnetic resonance images. After surgical excision of the mass and partial excision of the left atrial septum, histopathologic analysis confirmed the diagnosis of atrial myxoma. The patient was placed on preventive implantable cardioverter-defibrillator therapy and remained asymptomatic. The management of asymptomatic cardiac myxoma is a topic of debate, because no reports definitively favor either conservative or surgical measures.

  8. Atrial overdriving is beneficial in patients with atrial arrhythmias: first results of the PROVE Study.

    Science.gov (United States)

    Funck, R C; Adamec, R; Lurje, L; Capucci, A; Ritter, P; Shekan, D; Slegers, L C; Tavernier, R; Ishikawa, T

    2000-11-01

    The AF Prevention by Overdriving (PROVE) trial is an ongoing prospective study of the effectiveness of atrial overdrive pacing combined with an Automatic Rest Rate function in the prevention of atrial arrhythmias. All patients who have received a Talent DR 213 pacemaker are eligible for enrollment into the study. After a 1-month monitoring period, the patients are divided into two groups. Group I includes patients with > or = 2 appropriate mode-switch (MS) episodes, or 1 MS episode of > or = 10 minutes, and/or > 300 atrial runs of > 5 beats/month. Group II includes all other patients. The number and duration of atrial arrhythmias are measured the pacemaker's Automatic Interpretation and Data Analysis software (AIDA). Patients' quality-of-life is measured by a validated functional status questionnaire. After having been grouped, the patients are randomly assigned, in a crossover design, to standard DDDR or overdrive pacing + Rest Rate, each programmed for a 3-month period. Preliminary results in 78 patients show a 34% reduction in the mean number of MS, and a mean 48% shortening of the overall duration of the episodes by overdrive pacing + Rest Rate, achieved by a mean 84% prevalence of atrial pacing. Overdrive pacing + Rest Rate was well tolerated and associated with a slight improvement in quality-of-life.

  9. Atrial-selective K+ channel blockers: potential antiarrhythmic drugs in atrial fibrillation?

    Science.gov (United States)

    Ravens, Ursula

    2017-11-01

    In the wake of demographic change in Western countries, atrial fibrillation has reached an epidemiological scale, yet current strategies for drug treatment of the arrhythmia lack sufficient efficacy and safety. In search of novel medications, atrial-selective drugs that specifically target atrial over other cardiac functions have been developed. Here, I will address drugs acting on potassium (K+) channels that are either predominantly expressed in atria or possess electrophysiological properties distinct in atria from ventricles. These channels include the ultra-rapidly activating, delayed outward-rectifying Kv1.5 channel conducting IKur, the acetylcholine-activated inward-rectifying Kir3.1/Kir3.4 channel conducting IK,ACh, the Ca2+-activated K+ channels of small conductance (SK) conducting ISK, and the two-pore domain K+ (K2P) channels (tandem of P domains, weak inward-rectifying K+ channels (TWIK-1), TWIK-related acid-sensitive K+ channels (TASK-1 and TASK-3)) that are responsible for voltage-independent background currents ITWIK-1, ITASK-1, and ITASK-3. Direct drug effects on these channels are described and their putative value in treatment of atrial fibrillation is discussed. Although many potential drug targets have emerged in the process of unravelling details of the pathophysiological mechanisms responsible for atrial fibrillation, we do not know whether novel antiarrhythmic drugs will be more successful when modulating many targets or a single specific one. The answer to this riddle can only be solved in a clinical context.

  10. Atrial secretion of B-type natriuretic peptide

    DEFF Research Database (Denmark)

    Goetze, Jens Peter; Friis-Hansen, Lennart; Rehfeld, Jens F

    2006-01-01

    In the normal heart, the endocrine capacity resides in the atria. Atrial myocytes express and secrete natriuretic hormones that regulate fluid homeostasis and blood pressure. But in ventricular disease, atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) gene expression is also...... activated in ventricular myocytes. Plasma concentrations of natriuretic peptides and their biosynthetic precursors are accordingly increased in patients with marked ventricular dysfunction. In contrast, atrial peptide secretion in ventricular disease has received less attention, and our present...

  11. Clinical Features and Surgical Results of Right Atrial Myxoma.

    Science.gov (United States)

    Li, Han; Guo, Hongwei; Xiong, Hui; Xu, Jianping; Wang, Wei; Hu, Shengshou

    2016-01-01

    We retrospectively analyzed 367 patients receiving surgical resection of cardiac myxomas in our center over six years, and analyzed the incidence and surgical results of 28 cases of right atrial myxomas. We also compared the age, gender, and attached sites between left atrial myxoma and right atrial myxoma. Between January 2007 and December 2012, 28 patients with right atrial myxomas underwent surgical resection. There were 16 males and 12 females. The mean age was 47.77 ± 13.20 years (range: 8.00-79.00 years). Associated cardiac lesions included moderate and severe tricuspid regurgitation in four, coronary atherosclerotic heart disease in five, and pulmonary embolism in one. Twenty-seven patients (96.43%) were followed from 26 to 94 months (mean 55.78 ± 21.10 months). There was no early death after operation. The incidence of right atrial myxomas among sporadic cardiac myxomas was 7.89%. One patient died of lung cancer 34 months after myxoma resection. Two patients underwent coronary artery stent implantation due to coronary atherosclerotic heart disease during the follow-up period. One patient underwent myxoma resection due to recurrence in the left atrium four years after the first operation. There was no significant difference in the age between left atrial myxoma and right atrial myxoma (p > 0.05). There was a significant difference in the gender between left atrial myxomas and right atrial myxomas (p myxomas and right atrial myxomas are the atrial septum. Surgical resection of the right atrial myxoma results in good clinical outcomes and a decreased incidence of recurrence. © 2015 Wiley Periodicals, Inc.

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

    Science.gov (United States)

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

    2015-01-01

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

  13. The use of warfarin in veterans with atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Rosenbeck Karen

    2004-10-01

    Full Text Available Abstract Background Warfarin therapy is effective for the prevention of stroke in patients with atrial fibrillation. However, warfarin therapy is underutilized even among ideal anticoagulation candidates. The purpose of this study was to examine the use of warfarin in both inpatients and outpatients with atrial fibrillation within a Veterans Affairs (VA hospital system. Methods This retrospective medical record review included outpatients and inpatients with atrial fibrillation. The outpatient cohort included all patients seen in the outpatient clinics of the VA Connecticut Healthcare System during June 2000 with a diagnosis of atrial fibrillation. The inpatient cohort included all patients discharged from the VA Connecticut Healthcare System West Haven Medical Center with a diagnosis of atrial fibrillation during October 1999 – March 2000. The outcome measure was the rate of warfarin prescription in patients with atrial fibrillation. Results A total of 538 outpatients had a diagnosis of atrial fibrillation and 73 of these had a documented contraindication to anticoagulation. Among the 465 eligible outpatients, 455 (98% were prescribed warfarin. For the inpatients, a total of 212 individual patients were discharged with a diagnosis of atrial fibrillation and 97 were not eligible for warfarin therapy. Among the 115 eligible inpatients, 106 (92% were discharged on warfarin. Conclusions Ideal anticoagulation candidates with atrial fibrillation are being prescribed warfarin at very high rates within one VA system, in both the inpatient and outpatient settings; we found warfarin use within our VA was much higher than that observed for Medicare beneficiaries in our state.

  14. Atrial Thrombus in a Neonate: A Diagnostic Challenge

    Directory of Open Access Journals (Sweden)

    Alicia Sheen

    2015-04-01

    Full Text Available 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.

  15. Paroxysmal atrial fibrillation occurs often in cryptogenic ischaemic stroke

    DEFF Research Database (Denmark)

    Christensen, L M; Krieger, D W; Højberg, S

    2014-01-01

    BACKGROUND AND PURPOSE: Atrial fibrillation (AF) increases the risk of stroke fourfold and is associated with a poor clinical outcome. Despite work-up in compliance with guidelines, up to one-third of patients have cryptogenic stroke (CS). The prevalence of asymptomatic paroxysmal atrial fibrilla......BACKGROUND AND PURPOSE: Atrial fibrillation (AF) increases the risk of stroke fourfold and is associated with a poor clinical outcome. Despite work-up in compliance with guidelines, up to one-third of patients have cryptogenic stroke (CS). The prevalence of asymptomatic paroxysmal atrial...

  16. Pathogenic Mechanisms of Atrial Fibrillation in Obesity

    Directory of Open Access Journals (Sweden)

    O. M. Drapkina

    2016-01-01

    Full Text Available Atrial fibrillation (AF is one of the most common arrhythmias. It reduces quality of life and its duration due to thromboembolic complications. Obesity contributes to the structural and electrical remodeling of atrial myocardium. This leads to occurrence of ectopic foci in the mouths of the pulmonary veins and the disruption of normal electrical conduction in the atria. Systemic inflammation, myocardial fibrosis, cardiomyocyte overload by Na+ and Ca2+ ions, accumulation in the cells of unoxidized metabolic products, imbalance of the autonomic regulation are considered as the main mechanisms of arrhythmogenic substrate formation. Hypertension, insulin resistance, and obstructive sleep apnea, associated with obesity, increase the risk of development and progression of the arrhythmia. Study of pathogenetic mechanisms of AF in obesity is necessary to develop new strategies for its prevention and the creation of more effective methods of treatment of these patients.

  17. Cutaneous embolism of an atrial myxoma.

    Science.gov (United States)

    Rodríguez Bandera, Ana Isabel; Stewart, Nicholas Charles; Uribe, Pablo; Minocha, Rashi; Choi, James Young Joon

    2015-08-01

    Cardiac myxoma often presents with heterogeneous symptoms and signs and represents a challenging diagnosis. The cutaneous manifestations, if present, are often transient and non-specific and the clinician must possess a high degree of suspicion to secure the diagnosis. We present the case of a 36-year-old woman with a 6-month history of intermittent, painful, violaceous, non-blanching macules on the thumb and fingertips of the left hand and right ankle. A cutaneous embolic phenomenon was suspected and an urgent echocardiogram demonstrated an atrial mass, with subsequent histopathology confirming the clinical suspicion of atrial myxoma. Early diagnosis and excision of the tumour avoided serious complications. © 2015 The Australasian College of Dermatologists.

  18. Airplane wing deformation and flight flutter detection method by using three-dimensional speckle image correlation technology.

    Science.gov (United States)

    Wu, Jun; Yu, Zhijing; Wang, Tao; Zhuge, Jingchang; Ji, Yue; Xue, Bin

    2017-06-01

    Airplane wing deformation is an important element of aerodynamic characteristics, structure design, and fatigue analysis for aircraft manufacturing, as well as a main test content of certification regarding flutter for airplanes. This paper presents a novel real-time detection method for wing deformation and flight flutter detection by using three-dimensional speckle image correlation technology. Speckle patterns whose positions are determined through the vibration characteristic of the aircraft are coated on the wing; then the speckle patterns are imaged by CCD cameras which are mounted inside the aircraft cabin. In order to reduce the computation, a matching technique based on Geodetic Systems Incorporated coded points combined with the classical epipolar constraint is proposed, and a displacement vector map for the aircraft wing can be obtained through comparing the coordinates of speckle points before and after deformation. Finally, verification experiments containing static and dynamic tests by using an aircraft wing model demonstrate the accuracy and effectiveness of the proposed method.

  19. Flutter and Thermal Buckling Analysis for Composite Laminated Panel Embedded with Shape Memory Alloy Wires in Supersonic Flow

    Directory of Open Access Journals (Sweden)

    Chonghui Shao

    2016-01-01

    Full Text Available The flutter and thermal buckling behavior of laminated composite panels embedded with shape memory alloy (SMA wires are studied in this research. The classical plate theory and nonlinear von-Karman strain-displacement relation are employed to investigate the aeroelastic behavior of the smart laminated panel. The thermodynamic behaviors of SMA wires are simulated based on one-dimensional Brinson SMA model. The aerodynamic pressure on the panel is described by the nonlinear piston theory. Nonlinear governing partial differential equations of motion are derived for the panel via the Hamilton principle. The effects of ply angle of the composite panel, SMA layer location and orientation, SMA wires temperature, volume fraction and prestrain on the buckling, flutter boundary, and amplitude of limit cycle oscillation of the panel are analyzed in detail.

  20. Atrial Fibrillation During an Exploration Class Mission

    Science.gov (United States)

    Lipset, Mark A.; Lemery, Jay; Polk, J. D.; Hamilton, Douglas R.

    2010-01-01

    Background: A long-duration exploration class mission is fraught with numerous medical contingency plans. Herein, we explore the challenges of symptomatic atrial fibrillation (AF) occurring during an exploration class mission. The actions and resources required to ameliorate the situation, including the availability of appropriate pharmaceuticals, monitoring devices, treatment modalities, and communication protocols will be investigated. Challenges of Atrial Fibrillation during an Exploration Mission: Numerous etiologies are responsible for the initiation of AF. On Earth, we have the time and medical resources to evaluate and determine the causative situation for most cases of AF and initiate therapy accordingly. During a long-duration exploration class mission resources will be severely restricted. How is one to determine if new onset AF is due to recent myocardial infarction, pulmonary embolism, fluid overload, thyrotoxicosis, cardiac structural abnormalities, or CO poisoning? Which pharmaceutical therapy should be initiated and what potential side effects can be expected? Should anti-coagulation therapy be initiated? How would one monitor the therapeutic treatment of AF in microgravity? What training would medical officers require, and which communication strategies should be developed to enable the best, safest therapeutic options for treatment of AF during a long-duration exploration class mission? Summary: These questions will be investigated with expert opinion on disease elucidation, efficient pharmacology, therapeutic monitoring, telecommunication strategies, and mission cost parameters with emphasis on atrial fibrillation being just one illustration of the tremendous challenges that face a long-duration exploration mission. The limited crew training time, medical hardware, and drugs manifested to deal with such an event predicate that aggressive primary and secondary prevention strategies be developed to protect a multibillion-dollar asset like the

  1. Delay in diagnosis of right atrial myxoma

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Acute atrial fibrillation during dengue hemorrhagic fever

    Directory of Open Access Journals (Sweden)

    Veloso Henrique Horta

    2003-01-01

    Full Text Available Dengue fever is a viral infection transmitted by the mosquito, Aedes aegypti. Cardiac rhythm disorders, such as atrioventricular blocks and ventricular ectopic beats, appear during infection and are attributed to viral myocarditis. However, supraventricular arrhythmias have not been reported. We present a case of acute atrial fibrillation, with a rapid ventricular rate, successfully treated with intravenous amiodarone, in a 62-year-old man with dengue hemorrhagic fever, who had no structural heart disease.

  3. Left atrial reverse remodeling and prevention of progression of atrial fibrillation with atrial resynchronization device therapy utilizing dual-site right atrial pacing in patients with atrial fibrillation refractory to antiarrhythmic drugs or catheter ablation.

    Science.gov (United States)

    Nagarakanti, Rangadham; Slee, April; Saksena, Sanjeev

    2014-09-01

    Dual-site right atrial pacing (DAP) produces electrical atrial resynchronization but its long-term effect on the atrial mechanical function in patients with refractory atrial fibrillation (AF) has not been studied. Drug-refractory paroxysmal (PAF) and persistent AF (PRAF) patients previously implanted with a dual-site right atrial pacemaker (DAP) with minimal ventricular pacing modes (AAIR or DDDR mode with long AV delay) were studied. Echocardiographic structural (left atrial diameter [LAD] and left ventricular [LV] end diastolic diameter [EDD], end systolic diameter [ESD]) and functional (ejection fraction [EF]) parameters were serially assessed prior to, after medium-term (n = 39) and long-term (n = 34) exposure to DAP. During medium-term follow-up (n = 4.5 months), there was improvement in left atrial function. Mean peak A wave flow velocity increased with DAP as compared to baseline (75 ± 19 vs. 63 ± 23 cm/s, p = 0.003). The long-term impact of DAP was studied with baseline findings being compared with last follow-up data with a mean interval of 37 ± 25 (range 7-145) months. Mean LAD declined from 45 ± 5 mm at baseline to 42 ± 7 mm (p = 0.003). Mean LVEF was unchanged from 52 ± 9 % at baseline and 54 ± 6 % at last follow-up (p = 0.3). There was no significant change in LV dimensions with mean LVEDD being 51 ± 6 mm at baseline and 53 ± 5 mm at last follow-up (p = 0.3). Mean LVESD also remained unchanged from 35 ± 6 mm at baseline to 33 ± 6 mm at last follow-up (p = 0.47). During long-term follow-up, 30 patients (89 %) remained in sinus or atrial paced rhythm as assessed by device diagnostics at 3 years. DAP can achieve long-term atrial reverse remodeling and preserve LV systolic function. DAP when added to antiarrhythmic drug (AAD) and/or catheter ablation (ABL) maintains long-term rhythm control and prevents AF progression in elderly refractory AF patients

  4. Predictive value of various Doppler-derived parameters of atrial conduction time for successful atrial fibrillation ablation.

    Science.gov (United States)

    Shanks, Miriam; Valtuille, Lucas; Choy, Jonathan B; Becher, Harald

    2015-12-01

    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.

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

    Science.gov (United States)

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

    2016-01-01

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

  6. The mechanisms of atrial fibrillation in hyperthyroidism

    Directory of Open Access Journals (Sweden)

    Bielecka-Dabrowa Agata

    2009-04-01

    Full Text Available Abstract Atrial fibrillation (AF is a complex condition with several possible contributing factors. The rapid and irregular heartbeat produced by AF increases the risk of blood clot formation inside the heart. These clots may eventually become dislodged, causing embolism, stroke and other disorders. AF occurs in up to 15% of patients with hyperthyroidism compared to 4% of people in the general population and is more common in men and in patients with triiodothyronine (T3 toxicosis. The incidence of AF increases with advancing age. Also, subclinical hyperthyroidism is a risk factor associated with a 3-fold increase in development of AF. Thyrotoxicosis exerts marked influences on electrical impulse generation (chronotropic effect and conduction (dromotropic effect. Several potential mechanisms could be invoked for the effect of thyroid hormones on AF risk, including elevation of left atrial pressure secondary to increased left ventricular mass and impaired ventricular relaxation, ischemia resulting from increased resting heart rate, and increased atrial eopic activity. Reentry has been postulated as one of the main mechanisms leading to AF. AF is more likely if effective refractory periods are short and conduction is slow. Hyperthyroidism is associated with shortening of action potential duration which may also contribute to AF.

  7. Atrial Fibrillation in Eight New World Camelids.

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

    Smorodinova, Natalia; Bláha, Martin; Melenovský, Vojtěch; Rozsívalová, Karolína; Přidal, Jaromír; Ďurišová, Mária; Pirk, Jan; Kautzner, Josef; Kučera, Tomáš

    2017-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Natalia Smorodinova

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

  10. Cardiac magnetic resonance imaging and a rare case of an atrial myxoma causing an atrial septal defect

    Directory of Open Access Journals (Sweden)

    Matthew Grant, MD

    2017-12-01

    Full Text Available A 40 year-old athletic woman presented with worsening dyspnea on exertion over the preceding several months. Chest radiograph showed borderline cardiomegaly and subsequent echocardiography demonstrated a 5.0-cm left atrial mass as well as left-to-right interatrial shunting through a patent foramen ovale. Cardiac magnetic resonance imaging was performed, which demonstrated signal characteristics consistent with an atrial myxoma. The patient then underwent urgent surgical treatment with good technical and clinical outcome. Histologic examination confirmed an atrial myxoma. Cardiac magnetic resonance imaging was valuable in characterizing the nature of the atrial mass and patent foramen ovale, helping guide the surgical approach.

  11. Nonlocal and surface effects on the flutter instability of cantilevered nanotubes conveying fluid subjected to follower forces

    Energy Technology Data Exchange (ETDEWEB)

    Bahaadini, Reza [Department of Mechanical Engineering, Sirjan University of Technology, 78137-33385 Sirjan, Islamic Republic of Iran (Iran, Islamic Republic of); Hosseini, Mohammad, E-mail: hosseini@sirjantech.ac.ir [Department of Mechanical Engineering, Sirjan University of Technology, 78137-33385 Sirjan, Islamic Republic of Iran (Iran, Islamic Republic of); Jamalpoor, Ali [Department of Mechanical Engineering, Iran University of Science and Technology, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of)

    2017-03-15

    On the basis of nonlocal elasticity theory, this paper studies the dynamic structural instability behavior of cantilever nanotubes conveying fluid incorporating end concentrated follower force and distributed tangential load, resting on the visco-Pasternak substrate. In order to improve the accuracy of the results, surface effects, i.e. surface elasticity and residual stresses are considered. Extended Hamilton’s principle is implemented to obtain the nonlocal governing partial differential equation and related boundary conditions. Then, the extended Galerkin technique is used to convert partial differential equations into a general set of ordinary differential equations. Numerical results are expressed to reveal the variations of the critical flow velocity for flutter phenomenon of cantilever nanotubes with the various values of nonlocal parameter, mass ratios, nanotubes thickness, surface effects, various parameters of the visco-Pasternak medium, constant follower force and distributed compressive tangential load. Some numerical results of this research illustrated that the values of critical flutter flow velocity and stable region increase by considering surface effects. Also, critical flutter flow velocity decreases towards zero by increasing the value of the distributed compressive tangential load and constant follower force.

  12. [Low energy transcatheter atrial defibrillation in one patient with refractory atrial fibrillation].

    Science.gov (United States)

    Asenjo, R; Morris, R; Llancaqueo, M; Lopetegui, M; Marín, G; Morales, P

    1998-03-01

    Most cases of atrial fibrillation are converted with antiarrhythmic medications or external electric defibrillation. However, in some refractory patients, an internal transcatheter defibrillation must be attempted. We report a 50 years old male with an atrial fibrillation of one year duration that was refractory to pharmacological treatment and in whom external cardioversion was unsuccessful. After the application of a bifasic shock of 10 joules between a catheter in the right atrium and another one located at the coronary sinus, the patient was converted to sinus rhythm. At two months of follow up, the patient continues in sinus rhythm.

  13. Increased left atrial pressure in non-heart failure patients with subclinical hypothyroidism and atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Akinori Sairaku

    2016-05-01

    Full Text Available Background The impact of subclinical hypothyroidism on the cardiovascular risk is still debated. We aimed to measure the relationship between subclinical hypothyroidism and the left atrial (LA pressure. Methods The LA pressures and thyroid function were measured in consecutive patients undergoing atrial fibrillation (AF ablation, who did not have any known heart failure, structural heart disease, or overt thyroid disease. Results Subclinical hypothyroidism (4.5≤ thyroid-stimulating hormone 18 mmHg (odds ratio 3.94, 95% CI 1.28 11.2; P = 0.02. Conclusions Subclinical hypothyroidism may increase the LA pressure in AF patients.

  14. Low prevalence of connexin-40 gene variants in atrial tissues and blood from atrial fibrillation subjects

    Directory of Open Access Journals (Sweden)

    Tchou Gregory D

    2012-11-01

    Full Text Available Abstract Background The atrial gap junction protein connexin-40 (Cx40 has been implicated to play an important role in atrial conduction and development of atrial fibrillation (AF. However, the frequency of Cx40 mutations in AF populations and their impact on Cx40 expression remains unclear. In this study, we sought to identify polymorphisms in the Cx40 gene GJA5, investigate the potential functional role of these polymorphisms, and determine their allelic frequencies. The prevalence of nonsynonymous Cx40 mutations in blood and atrial tissue was also compared to mutation frequencies reported in prior studies. Methods We conducted direct sequencing of the GJA5 coding and 3′ UTR regions in blood samples from 91 lone AF subjects and 67 atrial tissue-derived samples from a lone cohort, a mixed AF cohort, and several transplant donors. Reporter gene transfection and tissue allelic expression imbalance assays were used to assess the effects of a common insertion/deletion polymorphism on Cx40 mRNA stability and expression. Results We identified one novel synonymous SNP in blood-derived DNA from a lone AF subject. In atrial tissue-derived DNA from lone and mixed AF subjects, we observed one novel nonsynonymous SNP, one rare previously reported synonymous SNP, and one novel 3′ UTR SNP. A previously noted 25 bp insertion/deletion polymorphism in the 3′ UTR was found to be common (minor allele frequency = 0.45 but had no effect on Cx40 mRNA stability and expression. The observed prevalence of nonsynonymous Cx40 mutations in atrial tissues derived from lone AF subjects differed significantly (p = 0.03 from a prior atrial tissue study reporting a high mutation frequency in a group of highly selected young lone AF subjects. Conclusions Our results suggest that Cx40 coding SNPs are uncommon in AF populations, although rare mutations in this gene may certainly lead to AF pathogenesis. Furthermore, a common insertion/deletion polymorphism in the Cx40 3

  15. The antiarrhythmic peptide analog ZP123 prevents atrial conduction slowing during metabolic stress

    DEFF Research Database (Denmark)

    Haugan, Ketil; Olsen, Kristine Boisen; Hartvig, Line

    2005-01-01

    OBJECTIVE: As atrial conduction slowing is important in the pathogenesis of atrial reentry arrhythmias, a drug that increases atrial conduction or prevents atrial conduction slowing could serve to prevent atrial reentry arrhythmias. In this study, we investigated whether the novel stable antiarrh......OBJECTIVE: As atrial conduction slowing is important in the pathogenesis of atrial reentry arrhythmias, a drug that increases atrial conduction or prevents atrial conduction slowing could serve to prevent atrial reentry arrhythmias. In this study, we investigated whether the novel stable...... antiarrhythmic peptide analog, ZP123, was able to prevent atrial conduction slowing. METHODS: We examined the effect of ZP123 on metabolic stress-induced changes in conduction velocity (CV) and on dynamic CV restitution in isolated left atria from male Sprague-Dawley rats. We performed binding of ZP123...

  16. Potassium channel gene mutations rarely cause atrial fibrillation

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    Nam Edwin G

    2006-08-01

    Full Text Available Abstract Background Mutations in several potassium channel subunits have been associated with rare forms of atrial fibrillation. In order to explore the role of potassium channels in inherited typical forms of the arrhythmia, we have screened a cohort of patients from a referral clinic for mutations in the channel subunit genes implicated in the arrhythmia. We sought to determine if mutations in KCNJ2 and KCNE1-5 are a common cause of atrial fibrillation. Methods Serial patients with lone atrial fibrillation or atrial fibrillation with hypertension were enrolled between June 1, 2001 and January 6, 2005. Each patient underwent a standardized interview and physical examination. An electrocardiogram, echocardiogram and blood sample for genetic analysis were also obtained. Patients with a family history of AF were screened for mutations in KCNJ2 and KCNE1-5 using automated sequencing. Results 96 patients with familial atrial fibrillation were enrolled. Eighty-three patients had lone atrial fibrillation and 13 had atrial fibrillation and hypertension. Patients had a mean age of 56 years at enrollment and 46 years at onset of atrial fibrillation. Eighty-one percent of patients had paroxysmal atrial fibrillation at enrollment. Unlike patients with an activating mutation in KCNQ1, the patients had a normal QTc interval with a mean of 412 ± 42 ms. Echocardiography revealed a normal mean ejection fraction of 62.0 ± 7.2 % and mean left atrial dimension of 39.9 ± 7.0 mm. A number of common polymorphisms in KCNJ2 and KCNE1-5 were identified, but no mutations were detected. Conclusion Mutations in KCNJ2 and KCNE1-5 rarely cause typical atrial fibrillation in a referral clinic population.

  17. Cardiac ion channels and mechanisms for protection against atrial fibrillation

    DEFF Research Database (Denmark)

    Grunnet, Morten; Bentzen, Bo Hjorth; Sørensen, Ulrik S

    2011-01-01

    Atrial fibrillation (AF) is recognised as the most common sustained cardiac arrhythmia in clinical practice. Ongoing drug development is aiming at obtaining atrial specific effects in order to prevent pro-arrhythmic, devastating ventricular effects. In principle, this is possible due to a different...

  18. Atrial Arrhythmias and Their Implications for Space Flight - Introduction

    Science.gov (United States)

    Polk, J. D.; Barr, Y. R.; Bauer, P.; Hamilton, D. R.; Kerstman, E.; Tarver, B.

    2010-01-01

    This panel will discuss the implications of atrial arrhythmias in astronauts from a variety of perspectives; including historical data, current practices, and future challenges for exploration class missions. The panelists will present case histories, outline the evolution of current NASA medical standards for atrial arrhythmias, discuss the use of predictive tools, and consider potential challenges for current and future missions.

  19. Atrial fibrillation in an adolescent--the agony of ecstasy.

    Science.gov (United States)

    Madhok, Ashish; Boxer, Robert; Chowdhury, Devyani

    2003-10-01

    Ecstasy (MDMA), a popular drug of abuse among teenagers, is thought to be "relatively" safe. A case of atrial fibrillation following the ingestion of ecstasy in a previously well adolescent is presented. Emergency room physicians should consider ecstasy abuse in the differential diagnosis of young patients presenting with atrial fibrillation.

  20. Dabigatran versus warfarin in patients with atrial fibrillation

    NARCIS (Netherlands)

    Connolly, Stuart J.; Ezekowitz, Michael D.; Yusuf, Salim; Eikelboom, John; Oldgren, Jonas; Parekh, Amit; Pogue, Janice; Reilly, Paul A.; Themeles, Ellison; Varrone, Jeanne; Wang, Susan; Alings, Marco; Xavier, Denis; Zhu, Jun; Diaz, Rafael; Lewis, Basil S.; Darius, Harald; Diener, Hans-Christoph; Joyner, Campbell D.; Wallentin, Lars; Connolly, S. J.; Ezekowitz, M. D.; Yusuf, S.; Eikelboom, J.; Oldgren, J.; Parekh, A.; Reilly, P. A.; Themeles, E.; Varrone, J.; Wang, S.; Palmcrantz-Graf, E.; Haehl, M.; Wallentin, L.; Alings, A. M. W.; Amerena, J. V.; Avezum, A.; Baumgartner, I.; Brugada, J.; Budaj, A.; Caicedo, V.; Ceremuzynski, L.; Chen, J. H.; Commerford, P. J.; Dans, A. L.; Darius, H.; Di Pasquale, G.; Diaz, R.; Erol, C.; Ferreira, J.; Flaker, G. C.; Flather, M. D.; Franzosi, M. G.; Gamboa, R.; Golitsyn, S. P.; Gonzalez Hermosillo, J. A.; Halon, D.; Heidbuchel, H.; Hohnloser, S. H.; Hori, M.; Huber, K.; Jansky, P.; Kamensky, G.; Keltai, M.; Kim, S.; Lau, C. P.; Le Heuzey, J. Y. F.; Lewis, B. S.; Liu, L. S.; Nanas, J.; Razali, O.; Pais, P. S.; Parkhomenko, A. N.; Pedersen, K. E.; Piegas, L. S.; Raev, D.; Simmers, T. A.; Smith, P. J.; Talajic, M.; Tan, R. S.; Tanomsup, S.; Toivonen, L.; Vinereanu, D.; Xavier, D.; Zhu, J.; Diener, H. C.; Joyner, C. D.; Diehl, A.; Ford, G.; Robinson, M.; Silva, J.; Sleight, P.; Wyse, D. G.; Collier, J.; de Mets, D.; Hirsh, J.; Lesaffre, E.; Ryden, L.; Sandercock, P.; Anastasiou-Nana, M. I.; Andersen, G.; Annex, B. H.; Atra, M.; Bornstein, N. M.; Boysen, G.; Brouwers, P. J. A. M.; Buerke, M.; Burrell, L. M.; Chan, Y. K.; Chen, W. H.; Cheung, R. T. F.; Divakaramenon, S.; Donnan, G. A.; Duray, G. Z.; Dvorakova, H.; Fiedler, J.; Gardinale, E.; Gates, P. C.; Goshev, E. G.; Goto, S.; Gross, B.; Guimaraes, H. P.; Gulkevych, O.; Haberl, R. L.; Hankey, G.; Hartikainen, J.; Healey, J.; Iliesiu, A. M.; Irkin, O.; Jaxa-Chamiec, T.; Jolly, S.; Kaste, K. A. M.; Kies, B.; Kostov, K. D.; Kristensen, K. S.; Labovitz, A. J.; Lassila, R. P. 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L.; Wilkinson, P. R.; Wilmott, R.; Wrigley, M. J.; Abadier, R.; Abbud, Z. A.; Adams, K. V.; Adler, S. W.; Agarwal, S.; Ahmed, A. M.; Ahmed, I. S.; Aiuto, M. A.; Albrittun, T. D.; Aliyar, P.; Allan, J. J.; Allen, D. P.; Allen, S. L.; Altschuller, A.; Amin, M.; Anand, I. S.; Antolick, A. B.; Arora, R.; Arouni, A. J.; Arslanian, C. L.; Asinger, R. W.; Aycock, G. R.; Bariciano, R. J.; Baron, S. B.; Barr, M. A.; Bartkowiak, A. J.; Baruch, L.; Basignani, C.; Bass, M. L.; Bean, B.; Bedwell, N. W.; Belber, A. D.; Belew, K.; Bell, Y. C.; Bellinger, R. L.; Bennett, W. T.; Bensimhon, D. R.; Benton, R.; Benton, R. E.; Ben-Yehuda, O.; Bertolet, B. D.; Betkowski, A. S.; Bilazarian, S. D.; Bissette, J. K.; Bobade, M. B.; Bolster, D. E.; Bomba, J.; Book, D. M.; Boscia, J. A.; Bouchard, A.; Bowman, L. M.; Bradley, A. J.; Brandt, H. D.; Bricker, C. R.; Brobyn, T. L.; Brock, R. I.; Broderick, T. M.; Broedlin, K.; Brown, A. M.; Browne, K. F.; Burke, S. W.; Burton, M. E.; Buser, G. A.; Capasso, M. K.; Caplan, W. E.; Cappelli, J.; Cardona, C.; Cardona, F.; Carlson, T.; Carr, K. W.; Casey, T.; Cashion, W. R.; Cass, D. T.; Chandrashekar, Y. S.; Changlani, M.; Chapla, P. G.; Chappell, J. H.; Chen, C.; Chen, Y.; Cho, N. R.; Cieszkowski, J. H.; Clark, D. M.; Clayton, R.; Clogston, C. W.; Cockrell, D. J.; Cohen, A. I.; Cohen, T. J.; Cole, J. F.; Conway, G.; Cook, V. R.; Cornish, A. L.; Cossu, S. F.; Costello, D. L.; Courtade, D. J.; Covelli, H. C.; Crenshaw, B. S.; Crews, L. A.; Crossley, G. H.; Culp, S. C.; Curtis, B. M.; Darrow, K.; de Raad, R. E.; DeGregorio, M.; DelNegro, A. A.; Denny, D. M.; Desai, V. S.; Deumite, N. J.; Dewey, L.; Dharawat, R. N.; Dobbs, B.; Donahue, S. M.; Downey, B.; Downing, J.; Drehobl, M. A.; Drewes, W. A.; Drucker, M. N.; Duff, R.; Duggal, M.; Dunlap, S. H.; Dunning, D. W.; DuThinh, V.; Dykstra, G. T.; East, C.; Eblaghie, M. C.; Edelstein, J.; Edmiston, W. A.; Eisen, H. J.; Eisenberg, S. J.; Ellis, J. R.; Ellison, H. S.; Ellsworth, S.; Elshahawy, M.; Emlein, G.; Entcheva, M.; Essandoh, L. K.; Estrada, A. Q.; Ewing, B.; Faillace, R. T.; Fanelli, A.; Farrell, P. W.; Farris, S. W.; Fattal, P. G.; Feigenblum, D. Y.; Feldman, G. J.; Fialkow, J. A.; Fiddler, K. M.; Fields, R. H.; Finkel, M. S.; Finn, C.; Fischell, T. A.; Fishbach, M.; Fishbein, G. J.; Fisher, M. M.; Fleischhauer, F. J.; Folk, T. G.; Folkerth, S. D.; Fortman, R. R.; Frais, M. A.; Friedman, D. C.; Fuchs, G.; Fuller, F.; Garibian, G.; Gee, F. H.; Gelernt, M. D.; Genovely, H. C.; Gerber, J. R.; Germano, J. J.; Giardina, J. J.; Gilbert, J. M.; Gillespie, E. L.; Gilman, E. M.; Gitler, B.; Givens, D. H.; Glover, R.; Gogia, H. S.; Gohn, D. C.; Goldberg, R. K.; Goldberger, J. J.; Goldscher, D. A.; Goldstein, M.; Goraya, T.; Gordon, D. F.; Gottlieb, D.; Grafner, H. L.; Graham, M.; Graves, M. W.; Graziano, M.; Greco, S. N.; Greenberg, M. L.; Greenspon, A. J.; Greer, G. S.; Griffin, D. D.; Grogan, E. W.; Groo, V. L.; Guarnieri, T.; Gupta, A.; Gupta, J.; Hack, T. C.; Hall, B.; Hallak, O.; Halpern, S. W.; Hamburg, C.; Hamroff, G. S.; Han, J.; Handel, F.; Hankins, S. R.; Hanovich, G. D.; Hanrahan, J. A.; Haque, I. U.; Hargrove, J. L.; Harnick, P. E.; Harris, J. L.; Hartley, P. A.; Haskel, E. J.; Hatch, D.; Haught, W. H.; Hearne, S.; Hearne, S. E.; Hemphill, J. A.; Henderson, D. A.; Henes, C. H.; Hengerer-Yates, T.; Hermany, P. R.; Herzog, W. R.; Hickey, K.; Hilton, T. C.; Hockstad, E. S.; Hodnett, P.; Hoffmeister, R.; Holland, J.; Hollenweger, L.; Honan, M. B.; Hoopes, D. A.; Hordes, A. R.; Hotchkiss, D. A.; Howard, M. A.; Howard, V. N.; Hulyalkar, A. R.; Hurst, P.; Hutchison, L. C.; Ingram, J.; Isakov, T.; Ison, R. K.; Israel, C. N.; Jackson, B. K.; Jackson, K. N.; Jacobson, A. K.; Jain, S.; Jarmukli, N. F.; Joffe, I.; Johnson, L. E.; Johnson, S. A.; Johnson, S. L.; Jones, A. A.; Joyce, D. B.; Judson, P. L.; Juk, S. S.; Kaatz, S.; Kaddaha, R. M.; Kaplan, K. J.; Karunaratne, H. B.; Kennett, J. D.; Kenton, D. M.; Kettunen, J. A.; Khan, M. A.; Khant, R. N.; Kirkwood, M. D.; Knight, B. P.; Knight, P. O.; Knutson, T. J.; Kobayashi, J. F.; Kogan, A.; Kogan, A. D.; Koren, M. J.; Kosinski, E. J.; Kosolcharoen, P.; Kostis, J. B.; Kramer, J. H.; Kramer, S. D.; Kron, J.; Kuchenrither, C. R.; Kulback, S. J.; Kumar, A.; Kushner, D.; Kutscher, A.; Lai, C. K.; Lam, J. B.; Landau, C.; Landzberg, J. S.; Lang, D. T.; Lang, J. M.; Lanzarotti, C. J.; Lascewski, D. L.; Lau, T. K.; Lee, J. K.; Lee, S.; Leimbach, W. N.; LePine, A. M.; Lesser, M. F.; Leuchak, S. H.; Levy, R. M.; Lewis, W. R.; Lincoln, T. L.; Lingerfelt, W. M.; Liston, M.; Liu, Z. G.; Lloret, R. L.; Lohrbauer, L.; Longoria, D. C.; Lott, B. M.; Louder, D. R.; Loukinen, K. L.; Lovell, J.; Lue, S.; Mackall, J. A.; Maletz, L.; Marlow, L.; Martin, R. C.; Matsumura, M.; McCartney, M. J.; McDuffie, D.; McGough, M. F.; McGrew, F. A.; McGuinn, Wm P.; McMillen, M. D.; McNeff, J.; McPherson, C. A.; Meengs, M. E.; Meengs, W. L.; Meholick, A. W.; Meisner, J. S.; Melucci, M. B.; Mercando, A.; Merlino, J. D.; Meymandi, S. K.; Miele, M. B.; Miller, R. H.; Miller, S. H.; Minor, S. T.; Mitchell, M. R.; Modi, M.; Mody, F. V.; Moeller, C. L.; Moloney, J. F.; Moran, J. E.; Morcos, N. C.; Morgan, A.; Mukherjee, S. K.; Mullinax, K.; Murphy, A. L.; Mustin, A. J.; Myers, G. I.; Naccarelli, G. V.; Nadar, V. K.; Nallasivan, M.; Navas, J. P.; Niazi, I. K.; Nsah, E. N.; Nunamaker, J. L.; Ochalek, T. B.; O'dea, D. J.; Ogilvie, P. D.; Olliff, B.; Omalley, A. K.; O'Neill, P. G.; Onufer, J. R.; Orchard, R. C.; Orihuela, L. A.; Ortiz, E. C.; O'Sullivan, M. T.; Padanilam, B. J.; Pandey, P.; Patel, D. V.; Patel, R. J.; Patel, V. B.; Patlola, R. R.; Pennock, G. D.; Perlman, R.; Peters, P. H.; Petrillo, A. V.; Pezzella, S.; Phillips, D.; Pierre-Louis, J. R.; Pilcher, G.; Pillai, C.; Pollock, S. G.; Pond, M. S.; Porterfield, J. K.; Presant, L.; Pressler, J.; Pribble, A. H.; Promisloff, S. D.; Pudi, K. K.; Putnam, D. L.; Quartner, J.; Quinn, J. C.; Quinnell, C. M.; Raad, G. L.; Rasmussen, L. A.; Ray, C.; Reiffel, J. A.; Reynertson, S.; Richardson, J. W.; Riley, C. P.; Rippy, J. S.; Rittelmeyer, J. T.; Roberts, D. M.; Robertson, R.; Robinson, V. J. B.; Rocco, T. A.; Rosenbaum, D.; Roth, E. M.; Rottman, J. N.; Rough, R. R.; Rubenstein, J. J.; Sakkal, A. M.; Saleem, T.; Salerno, D. M.; Samendinger, M. L.; Sandeno, S.; Santilli, T. M.; Santucci, P.; Sattar, P.; Saxman, K. A.; Schaefer, S.; Schmidt, J.; Schneider, R. M.; Schocken, D. D.; Schrader, M. K.; Schramm, B. A.; Schultz, R. W.; Schussheim, A. E.; Schwarz, E. F.; Seamon, M. C.; Sestero, J. D.; Shah, M. P.; Shah, R.; Shalaby, A.; Shanes, J. G.; Sheftel, G. L.; Sheikh, K. H.; Shein, A. B.; Shemonsky, N. K.; Shepler, A.; Sheridan, E.; Shipwash, T. M.; Shopnick, R. I.; Short, W. G.; Shoukfeh, M. F.; Sibia, R. S.; Siler, T. M.; Silva, J. A.; Simons, G. R.; Simpson, A. G.; Simpson, H. R.; Simpson, V. J.; Singh, B. N.; Singh, N.; Singh, V. N.; Sitz, C. J.; Skatrud, L.; Sklar, J.; Slotwiner, D. J.; Smith, P. F.; Smith, P. N.; Smith, R. H.; Smith, J. E.; Sodowick, B. C.; Solomon, A. J.; Soltero, E. A.; Sonel, A. F.; Sperling, R.; Spiller, C.; Spink, B. Z.; Sprinkle, L. W.; Spyropoulos, A. C.; Stamos, T. D.; Steljes, A. D.; Stillabower, M. E.; Stover, T.; Strain, J. E.; Strickland, T. L.; Suresh, D. P.; Takata, T. S.; Taylor, J. S.; Taylor, M.; Teague, S. M.; Teixeia, J. M.; Telfer, E. A.; Terry, P. S.; Terry, R. W.; Thai, H. M.; Thalin, M.; Thomas, V. N.; Thompson, C. A.; Thompson, M. A.; Thornton, J. W.; Tidman, R. E.; Toler, B. S.; Traina, M. I.; Trippi, J. A.; Ujiiye, D. L.; Usedom, J. E.; van de Graaff, E.; van de Wall, L. R.; Vaughn, J. W.; Ver Steeg, D.; Vicari, R. M.; Vijay, N.; Vitale, C. B.; Vlastaris, A. G.; Voda, J.; Vora, K. N.; Voyles, W. F.; Vranian, R. B.; Vrooman, P. S.; Waack, P.; Waldo, A. L.; Walker, J. L.; Wallace, M. A.; Walsh, E. A.; Walsh, R. L.; Walton, A.; Washam, M.; Wehner, P. S.; Wei, J. Y.; Weiner, S.; Weiss, R. J.; Wells, D. M.; Wera-Archakul, W.; Wertheimer, J. H.; West, S. A.; Whitaker, J. H.; White, M. L.; White, R. H.; Whitehill, J. N.; Wiegman, P. J.; Wiesel, J.; Williams, J.; Williams, L. E.; Williams, M. L.; Williamson, V. K.; Wilson, V. E.; Wilson, W. W.; Woodfield, S. L.; Wulff, C. W.; Yates, S. W.; Yousuf, K. A.; Zakhary, B. G.; Zambrano, R.; Zimetbaum, P.; Zoble, R.; Zopo, A. R.; Zwerner, P. L.

    2009-01-01

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

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

    African Journals Online (AJOL)

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

  2. Imaging of cerebral infarction caused by atrial myxoma

    Energy Technology Data Exchange (ETDEWEB)

    Gee, G.T. (Neuroradology Section, Univ. of Texas Health Science Center, San Antonio, TX (United States)); Bazan, C. III (Neuroradology Section, Univ. of Texas Health Science Center, San Antonio, TX (United States)); Jinkins, J.R. (Neuroradology Section, Univ. of Texas Health Science Center, San Antonio, TX (United States))

    1994-05-01

    We describe the radiologic investigation of two patients with primary left atrial myxoma who presented with embolic manifestations in the brain. MRI and CT showed multiple infarcts, while the cardiac atrial mass was demonstrated in one of the patients by MRI and in both by echocardiography. (orig.)

  3. Ocular and Cerebral Emboli From an Atrial Myxoma.

    Science.gov (United States)

    Kuonen, Anne; Borruat, François-Xavier

    2017-09-01

    Emboli from an atrial myxoma resulted in asymptomatic segmental retinal and choroidal arterial hyperfluorescent lesions on retinal angiography, mimicking an arteritis. The retinal lesions disappeared after removal of the atrial myxoma. Endothelial trauma by embolic material appears to be the mechanism of the angiographic findings.

  4. Atrial natriuretic peptide regulates adipose tissue accumulation in adult atria

    Science.gov (United States)

    Suffee, Nadine; Moore-Morris, Thomas; Farahmand, Patrick; Rücker-Martin, Catherine; Dilanian, Gilles; Fradet, Magali; Sawaki, Daigo; Derumeaux, Geneviève; LePrince, Pascal; Clément, Karine; Dugail, Isabelle; Puceat, Michel; Hatem, Stéphane N.

    2017-01-01

    The abundance of epicardial adipose tissue (EAT) is associated with atrial fibrillation (AF), the most frequent cardiac arrhythmia. However, both the origin and the factors involved in EAT expansion are unknown. Here, we found that adult human atrial epicardial cells were highly adipogenic through an epithelial–mesenchymal transition both in vitro and in vivo. In a genetic lineage tracing the WT1CreERT2+/−RosatdT+/− mouse model subjected to a high-fat diet, adipocytes of atrial EAT derived from a subset of epicardial progenitors. Atrial myocardium secretome induces the adipogenic differentiation of adult mesenchymal epicardium-derived cells by modulating the balance between mesenchymal Wingless-type Mouse Mammary Tumor Virus integration site family, member 10B (Wnt10b)/β-catenin and adipogenic ERK/MAPK signaling pathways. The adipogenic property of the atrial secretome was enhanced in AF patients. The atrial natriuretic peptide secreted by atrial myocytes is a major adipogenic factor operating at a low concentration by binding to its natriuretic peptide receptor A (NPRA) receptor and, in turn, by activating a cGMP-dependent pathway. Hence, our data indicate cross-talk between EAT expansion and mechanical function of the atrial myocardium. PMID:28096344

  5. Oral antiarrhythmic drugs in converting recent onset atrial fibrillation

    NARCIS (Netherlands)

    Deneer, Vera H. M.; Borgh, Marieke B. I.; Kingma, J. Herre; Lie-A-Huen, Loraine; Brouwers, Jacobus R. B. J.

    2004-01-01

    AIM: This article reviews clinical studies on oral antiarrhythmic drugs in converting recent onset atrial fibrillation. An oral loading dose of an antiarrhythmic drug for cardioversion of atrial fibrillation could be an option, due to its simplicity, both for patients admitted to outpatient

  6. New antiarrhythmic drugs for treatment of atrial fibrillation.

    Science.gov (United States)

    Dobrev, Dobromir; Nattel, Stanley

    2010-04-03

    Inadequacies in current therapies for atrial fibrillation have made new drug development crucial. Conventional antiarrhythmic drugs increase the risk of ventricular proarrhythmia. In drug development, the focus has been on favourable multichannel-blocking profiles, atrial-specific ion-channels, and novel non-channel targets (upstream therapy). Molecular modification of the highly effective multichannel blocker, amiodarone, to improve safety and tolerability has produced promising analogues such as dronedarone, although this drug seems less effective than does amiodarone. Vernakalant, an atrial-selective drug with reduced proarrhythmic risk, might be useful for cardioversion in atrial fibrillation. Ranolazine, another atrial-selective agent initially developed as an antianginal, has efficacy for atrial fibrillation and is being tested in prospective clinical trials. So-called upstream therapy with angiotensin-converting enzyme and angiotensin-receptor inhibitors, statins, or omega-3 fatty acids and fish oil that target atrial remodelling could be effective, but need further clinical validation. We focus on the basic and clinical pharmacology of newly emerging antiarrhythmic drugs and non-traditional approaches such as upstream therapy for atrial fibrillation. Copyright 2010 Elsevier Ltd. All rights reserved.

  7. Failure of right atrial premature beats to reset atriofascicular tachycardia.

    Science.gov (United States)

    Porkolab, F L; Alpert, B L; Scheinman, M M

    1999-03-01

    A patient with a right atriofascicular (Mahaim) tachycardia was found to have inducible antidromic supraventricular tachycardia, but atrial premature beats from the right atrial free wall failed to reset the tachycardia. An interesting transition from AV nodal reentry tachycardia to Mahaim tachycardia is also presented.

  8. Radiofrequency ablation as initial therapy in paroxysmal atrial fibrillation

    DEFF Research Database (Denmark)

    Cosedis Nielsen, Jens; Johannessen, Arne; Raatikainen, Pekka

    2012-01-01

    There are limited data comparing radiofrequency catheter ablation with antiarrhythmic drug therapy as first-line treatment in patients with paroxysmal atrial fibrillation.......There are limited data comparing radiofrequency catheter ablation with antiarrhythmic drug therapy as first-line treatment in patients with paroxysmal atrial fibrillation....

  9. Assessment of left atrial volume and function in patients with permanent atrial fibrillation

    DEFF Research Database (Denmark)

    Agner, Bue F Ross; Kühl, Jørgen Tobias; Linde, Jesper James

    2014-01-01

    Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with substantial morbidity and mortality. AF is associated with enlargement of the left atrium (LA), and the LA volume has important prognostic implications for the disease. The objective of the study was to determine how...

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

    DEFF Research Database (Denmark)

    Poulet, Claire; Wettwer, Erich; Grunnet, Morten

    2015-01-01

    Slowly inactivating Na+ channels conducting "late" Na+ current (INa,late) contribute to ventricular arrhythmogenesis under pathological conditions. INa,late was also reported to play a role in chronic atrial fibrillation (AF). The objective of this study was to investigate INa,late in human right...

  11. Does Myocardial Infarction Beget Atrial Fibrillation and Atrial Fibrillation Beget Myocardial Infarction?

    NARCIS (Netherlands)

    Vermond, Rob A.; Van Gelder, Isabelle C.; Crijns, Harry J.; Rienstra, Michiel

    2015-01-01

    Atrial fibrillation (AF) affects millions of people worldwide.(1) It is already known several decades that AF is not a benign condition, and it's associated with a 5-fold increased risk of stroke, 3-fold increased risk of heart failure, and doubling of risk of dementia and death.(2-4) Myocardial

  12. Atrial fibrillation and vascular disease-a bad combination

    DEFF Research Database (Denmark)

    Bjerring Olesen, Jonas; Gislason, Gunnar Hilmar; Torp-Pedersen, Christian

    2012-01-01

    This article provides an overview of (i) the risk of stroke associated with vascular disease (acute coronary syndromes and peripheral artery disease) in patients with atrial fibrillation, (ii) the frequent coexistence of vascular disease in patients with atrial fibrillation and, (iii......) the cardiovascular risk associated with the coexisting of the two diseases. The literature on this topic is relatively sparse, and we discuss results from both clinical trials and observational studies. There is a clear indication of an increased stroke risk associated with vascular disease in patients with atrial...... fibrillation. Indeed, patients with atrial fibrillation often had coexisting vascular disease (around 18%), and the combination of the two diseases substantially increases the risk of future cardiovascular events. The increased risk associated with peripheral artery disease in atrial fibrillation is even more...

  13. Anomalous muscle bundle in the right atrium; Implication to trans atrial device closure

    Directory of Open Access Journals (Sweden)

    Saji Philip

    2017-09-01

    Full Text Available Intracavitary muscle bands or aberrant bands have been well described in all four chambers of the heart but rarely seen thick muscular band crossing right atrium. We report a case of devisable secundum atrial septal defect with an intra-atrial anomalous muscular band, crossing right atrial wall to the rim of the secundum atrial septal defect warranting surgical closure.

  14. Progression of atrial fibrillation in the REgistry on Cardiac rhythm disORDers assessing the control of Atrial Fibrillation cohort

    DEFF Research Database (Denmark)

    De Vos, Cees B; Breithardt, Günter; Camm, A John

    2012-01-01

    Paroxysmal atrial fibrillation (AF) may progress to persistent AF. We studied the clinical correlates and the effect of rhythm-control strategy on AF progression.......Paroxysmal atrial fibrillation (AF) may progress to persistent AF. We studied the clinical correlates and the effect of rhythm-control strategy on AF progression....

  15. Aeroelastic flutter enhancement by exploiting the combined use of shape memory alloys and nonlinear piezoelectric circuits

    Science.gov (United States)

    Sousa, Vagner Candido de; Silva, Tarcísio Marinelli Pereira; De Marqui Junior, Carlos

    2017-10-01

    In this paper, the combined effects of semi-passive control using shunted piezoelectric material and passive pseudoelastic hysteresis of shape memory springs on the aerolastic behavior of a typical section is investigated. An aeroelastic model that accounts for the presence of both smart materials employed as mechanical energy dissipation devices is presented. The Brinson model is used to simulate the shape memory material. New expressions for the modeling of the synchronized switch damping on inductor technique (developed for enhanced piezoelectric damping) are presented, resulting in better agreement with experimental data. The individual effects of each nonlinear mechanism on the aeroelastic behavior of the typical section are first verified. Later, the combined effects of semi-passive piezoelectric control and passive shape memory alloy springs on the post-critical behavior of the system are discussed in details. The range of post-flutter airflow speeds with stable limit cycle oscillations is significantly increased due to the combined effects of both sources of energy dissipation, providing an effective and autonomous way to modify the behavior of aeroelastic systems using smart materials.

  16. New Look at Nonlinear Aerodynamics in Analysis of Hypersonic Panel Flutter

    Directory of Open Access Journals (Sweden)

    Dan Xie

    2017-01-01

    Full Text Available A simply supported plate fluttering in hypersonic flow is investigated considering both the airflow and structural nonlinearities. Third-order piston theory is used for nonlinear aerodynamic loading, and von Karman plate theory is used for modeling the nonlinear strain-displacement relation. The Galerkin method is applied to project the partial differential governing equations (PDEs into a set of ordinary differential equations (ODEs in time, which is then solved by numerical integration method. In observation of limit cycle oscillations (LCO and evolution of dynamic behaviors, nonlinear aerodynamic loading produces a smaller positive deflection peak and more complex bifurcation diagrams compared with linear aerodynamics. Moreover, a LCO obtained with the linear aerodynamics is mostly a nonsimple harmonic motion but when the aerodynamic nonlinearity is considered more complex motions are obtained, which is important in the evaluation of fatigue life. The parameters of Mach number, dynamic pressure, and in-plane thermal stresses all affect the aerodynamic nonlinearity. For a specific Mach number, there is a critical dynamic pressure beyond which the aerodynamic nonlinearity has to be considered. For a higher temperature, a lower critical dynamic pressure is required. Each nonlinear aerodynamic term in the full third-order piston theory is evaluated, based on which the nonlinear aerodynamic formulation has been simplified.

  17. Time domain flutter analysis of cascades using a full-potential solver

    Science.gov (United States)

    Bakhle, Milind A.; Reddy, T. S. R.; Keith, Theo G., Jr.

    1990-01-01

    A time domain approach is used to determine the dynamic aeroelastic stability of a cascade of blades. The structural model for each blade is a typical section with two degrees of freedom. The aerodynamic model is the unsteady, two-dimensional, full-potential flow through the cascade of airfoils. The unsteady equations of motion for the structure and the fluid are integrated simultaneously in time starting with the steady flowfield and a small initial disturbance applied to the airfoils. The motion of each blade is analyzed to determine the aeroelastic stability of the cascade. The effect of interblade phase angle is included in the analysis by allowing each blade to have an independent motion and considering a number of blade passages. Calculations are made using an airfoil section and structural parameters that are representative of a propfan. The results are compared with those from a separate frequency domain analysis. Good agreement between the results is observed. With the time domain approach, it is possible to consider nonlinear structural models and nonlinear force-displacement relations. The method allows a realistic simulation of the motion of the fluid and the cascade blades for a better physical understanding and it also has the potential for saving computational time when compared to the frequency domain approach for the flutter analysis of cascades.

  18. Whirl Flutter Stability of Two-Bladed Proprotor/Pylon Systems In High Speed Flight

    Science.gov (United States)

    Singh, Beerinder; Chopra, Inderjit; Pototzky, A. (Technical Monitor)

    2002-01-01

    The lack of polar symmetry in two-bladed rotors leads to equations of motion with periodic coefficients in axial flight, which is contrary to three or more bladed rotors that result in constant coefficient equations. With periodic coefficients, the analysis becomes involved, as a result very few studies have been directed towards the analysis of two-bladed rotors. In this paper, the aeroelastic stability of two-bladed proprotor/pylon/wing combinations is examined in high speed axial flight. Several parametric studies are carried out to illustrate the special nature of two-bladed proprotors and to better understand the mechanism of whirl-flutter in such rotors. The wing beam bending mode for two-bladed rotors is found to be stable over the range of parameters examined, a behaviour very different from three-bladed rotors. Also, the wing torsion mode exhibits a new type of instability similar to a wing torsional divergence scouring at I/rev frequency. This type of behaviour is not seen in three and more bladed rotors. The interaction between wing chordwise bending and torsion modes is found to be much greater in the case of two-bladed rotors and, over the range of parameters considered, these two modes govern the stability of the system.

  19. A Comparative Assessment of Aerodynamic Models for Buffeting and Flutter of Long-Span Bridges

    Directory of Open Access Journals (Sweden)

    Igor Kavrakov

    2017-12-01

    Full Text Available Wind-induced vibrations commonly represent the leading criterion in the design of long-span bridges. The aerodynamic forces in bridge aerodynamics are mainly based on the quasi-steady and linear unsteady theory. This paper aims to investigate different formulations of self-excited and buffeting forces in the time domain by comparing the dynamic response of a multi-span cable-stayed bridge during the critical erection condition. The bridge is selected to represent a typical reference object with a bluff concrete box girder for large river crossings. The models are viewed from a perspective of model complexity, comparing the influence of the aerodynamic properties implied in the aerodynamic models, such as aerodynamic damping and stiffness, fluid memory in the buffeting and self-excited forces, aerodynamic nonlinearity, and aerodynamic coupling on the bridge response. The selected models are studied for a wind-speed range that is typical for the construction stage for two levels of turbulence intensity. Furthermore, a simplified method for the computation of buffeting forces including the aerodynamic admittance is presented, in which rational approximation is avoided. The critical flutter velocities are also compared for the selected models under laminar flow.

  20. Immediate and long-term atrial sensing stability in single-lead VDD pacing depends on right atrial dimensions.

    Science.gov (United States)

    Santini, M; Ricci, R; Pignalberi, C; Auriti, A; Pepe, M; Assale, R; Caporicci, D

    2001-10-01

    Single-pass VDD is a physiological stimulation mode which requires a single-lead with a floating dipole to detect the atrial signal. We investigated the impact of right heart dimensions on immediate and long-term atrial sensing stability in VDD systems to draw guidelines for optimal atrial sensitivity programming. Forty-one patients (23 males, mean age 73 +/- 11 years) with II or III degree AV block and normal sinus node function received a Thera VDD Medtronic 8948 pulse generator with Medtronic 5032 lead. Atrial sensing was evaluated at pre-discharge and during 12-months follow-up in the supine and upright positions, during normal and forced breathing. Atrial sensing variability, quantified by a D value (mV), which represents the difference between the maximum and the minimum atrial electrogram amplitude obtained during the various activities, was analyzed and related to right heart dimensions measured at echocardiography. Long-term appropriate atrial sensing was obtained in 40/41 patients. P wave mean amplitude at pre-discharge, during every specific activity, was predictive of 12-month values. No atrial oversensing was observed. According to the right atrial dimension (RAD), patients with RAD > 38 mm had a sensing variability significantly higher than those with RAD relationship between D and RAD dimensions was observed (r=0.47; Pdistance from the roof of the right atrium to the right ventricular apex (RAVD), patients with RAVD 93 mm had D=0.5 +/- 0.4; P 30 mm and RAVD < 80 mm) at high risk of loss of AV synchrony with 67% sensitivity and 80% specificity. Nevertheless, apart from heart dimensions, no patient showed an atrial signal amplitude lower than 0.3 mV. According to our data, in VDD single-lead systems the amplitude of the atrial signal is stable over time in every physical activity. High RAD and low RAVD values may select patients with poor atrial sensing stability. Anyway, taking into account that no atrial oversensing was observed, atrial sensitivity

  1. Chronic ventricular pacing with ventriculo-atrial conduction versus atrial pacing in three patients with symptomatic sinus bradycardia.

    Science.gov (United States)

    El Gamal, M I; Van Gelder, L M

    1981-01-01

    Three patients with symptomatic sinus bradycardia due to sick sinus syndrome were treated with permanent ventricular pacing for periods ranging from 2.5 to 4 years. All three patients had ventriculo-atrial conduction on routine electrocardiography. Although ventricular pacing was effective, they complained of fatigue, lightheadedness, and near syncope. Hemodynamic studies revealed the presence of regular cannon waves in the right atrium as well as in the pulmonary artery wedge pressure curves. Temporary atrial pacing resulted in disappearance of the cannon waves and a significant rise in cardiac output (32-48%). After normal atrio-ventricular conduction was confirmed by rapid atrial stimulation and His bundle electrocardiography, the pacing mode was changed to permanent atrial pacing on demand. The effort tolerance of the patients markedly improved, and the previously mentioned symptoms disappeared. Control hemodynamic studies 9 to 12 months after implantation of the atrial demand pacemaker showed that the improvement in cardiac performance was maintained.

  2. Combined percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation for rheumatic mitral stenosis and atrial fibrillation

    Energy Technology Data Exchange (ETDEWEB)

    Murdoch, Dale, E-mail: dale_murdoch@health.qld.gov.au [The Prince Charles Hospital, Brisbane (Australia); The University of Queensland, Brisbane (Australia); McAulay, Laura [The Prince Charles Hospital, Brisbane (Australia); Walters, Darren L. [The Prince Charles Hospital, Brisbane (Australia); The University of Queensland, Brisbane (Australia)

    2014-11-15

    Rheumatic heart disease is a common cause of cardiovascular morbidity and mortality worldwide, mostly in developing countries. Mitral stenosis and atrial fibrillation often coexist, related to both structural and inflammatory changes of the mitral valve and left atrium. Both predispose to left atrial thrombus formation, commonly involving the left atrial appendage. Thromboembolism can occur, with devastating consequences. We report the case of a 62 year old woman with rheumatic heart disease resulting in mitral stenosis and atrial fibrillation. Previous treatment with warfarin resulted in life-threatening gastrointestinal bleeding and she refused further anticoagulant therapy. A combined procedure was performed, including percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation with the Atritech® Watchman® device. No thromboembolic or bleeding complications were encountered at one year follow-up. Long-term follow-up in a cohort of patients will be required to evaluate the safety and efficacy of this strategy.

  3. Low-energy multistage atrial defibrillation therapy terminates atrial fibrillation with less energy than a single shock.

    Science.gov (United States)

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

    2011-12-01

    Implantable device therapy of atrial fibrillation (AF) is limited by pain from high-energy shocks. We developed a low-energy multistage defibrillation therapy and tested it in a canine model of AF. AF was induced by burst pacing during vagus nerve stimulation. Our novel defibrillation therapy consisted of 3 stages: stage (ST) 1 (1-4 low-energy biphasic [BP] shocks), ST2 (6-10 ultralow-energy monophasic [MP] shocks), and ST3 (antitachycardia pacing). First, ST1 testing compared single or multiple MP and BP shocks. Second, several multistage therapies were tested: ST1 versus ST1+ST3 versus ST1+ST2+ST3. Third, 3 shock vectors were compared: superior vena cava to distal coronary sinus, proximal coronary sinus to left atrial appendage, and right atrial appendage to left atrial appendage. The atrial defibrillation threshold (DFT) of 1 BP shock was defibrillation at or below the pain threshold.

  4. Echocardiographic study of left atrial myxoma

    Directory of Open Access Journals (Sweden)

    Dalal J

    1979-01-01

    Full Text Available Four cases of left atrial myxoma were diagnosed pre-operatively by echocardiography. All cases showed characteristic echocardio-graphic features of variegated shadows behind the mitral valve in diastole and within the left atrium in systole. In two cases the my-xomas were surgically removed and confirmed on histology. In one case the post-operative echocardiogram showed complete dis-appearance of the abnormal shadows. Echocardiography is the most reliable method today for the diagnosis of a myxoma.

  5. Integrating new approaches to atrial fibrillation management

    DEFF Research Database (Denmark)

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

    2018-01-01

    cardiovascular events. New approaches to AF management, including the use of novel technologies and structured, integrated care, have the potential to enhance clinical phenotyping or result in better treatment selection and stratified therapy. Here, we report the outcomes of the 6th Consensus Conference...... of the Atrial Fibrillation Network (AFNET) and the European Heart Rhythm Association (EHRA), held at the European Society of Cardiology Heart House in Sophia Antipolis, France, 17-19 January 2017. Sixty-two global specialists in AF and 13 industry partners met to develop innovative solutions based on new...

  6. Concomitant atrial fibrillation surgery: worth the effort?

    Science.gov (United States)

    Nashef, Samer A M; Abu-Omar, Yasir

    2017-12-08

    Concomitant surgery for atrial fibrillation is a conceptually and clinically difficult area of cardiac surgical decision making. This review introduces the pathophysiological background, provides insight and guidance for cardiac surgeons on some of the conflicting evidence and claims, and explores the fields in which further research may help elucidate a cardiac surgical clinical strategy for tackling this common and potentially lethal form of arrhythmia. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  7. Current approaches in atrial fibrillation treatment

    Directory of Open Access Journals (Sweden)

    Cenk Sarı

    2014-09-01

    Full Text Available Atrial fibrillation (AF is the most common sustained arrhythmia encountered in clinical practice. Its incidence increases with age. AF is classified into subtypes according to the duration and/or able to provide sinus rhytym. İnitially, patients should be evaluated for rhythm or rate control for appropriate treatment. Second stage of strategy aimed to investigate the feasibility of anticoagulation therapy. Recently, due to the progress made in treatment with rhythm control and anticoagulation therapy, either American or European guidelines have been renovated. These developments have taken place in the newly published guide. In this article, the current change in the management of AF is discussed.

  8. Association of left atrial function and left atrial enhancement in patients with atrial fibrillation: cardiac magnetic resonance study.

    Science.gov (United States)

    Habibi, Mohammadali; Lima, Joao A C; Khurram, Irfan M; Zimmerman, Stefan L; Zipunnikov, Vadim; Fukumoto, Kotaro; Spragg, David; Ashikaga, Hiroshi; Rickard, John; Marine, Joseph E; Calkins, Hugh; Nazarian, Saman

    2015-02-01

    Atrial fibrillation (AF) is associated with left atrial (LA) structural and functional changes. Cardiac magnetic resonance late gadolinium enhancement (LGE) and feature-tracking are capable of noninvasive quantification of LA fibrosis and myocardial motion, respectively. We sought to examine the association of phasic LA function with LA enhancement in patients with AF. LA structure and function was measured in 90 patients with AF (age 61±10 years; 76% men) referred for ablation and 14 healthy volunteers. Peak global longitudinal LA strain, LA systolic strain rate, and early and late diastolic strain rates were measured using cine-cardiac magnetic resonance images acquired during sinus rhythm. The degree of LGE was quantified. Compared with patients with paroxysmal AF (60% of cohort), those with persistent AF had larger maximum LA volume index (56±17 versus 49±13 mL/m(2); P=0.036), and increased LGE (27.1±11.7% versus 36.8±14.8%; Prate, early diastolic strain rate, and late diastolic strain rate) were lower in patients with persistent AF (Prate, early diastolic strain rate, and late diastolic strain rate (Pmeasurement of LA function using feature-tracking cardiac magnetic resonance may add important information about the physiological importance of LA fibrosis. © 2015 American Heart Association, Inc.

  9. Facilitating internal cardioversion of chronic atrial fibrillation with ibutilide--predictors of atrial defibrillation-threshold decrease.

    Science.gov (United States)

    Efremidis, Michalis; Sideris, Antonis; Batra, Ravinder; Manolatos, Dimitrios; Xidonas, Sotirios; Kardara, Dimitra; Ekonomou, Dimitrios; Evagelou, Dimitrios; Filippatos, Gerasimos; Kardaras, Fotios

    2004-06-01

    Internal atrial cardioversion has been successfully used in the treatment of atrial fibrillation. The object of this study was to depict the effect of ibutilide on sinus rhythm restoration and internal atrial defibrillation threshold in patients with chronic atrial fibrillation. Twenty-four patients (14 men and 10 women, mean age 63.16+/-8.55 years) with chronic atrial fibrillation were cardioverted using a single-lead system. The distal coil of the defibrillator catheter was placed in the coronary sinus and the proximal coil at the junction of the superior vena cava and the high right atrium. Synchronized biphasic shocks were applied using a step-up protocol from 1 to 30 joules until sinus rhythm was restored. In all patients with successful cardioversion, atrial fibrillation was reinduced and second cardioversion was attempted after intravenous administration of 1 mg ibutilide. Successful internal cardioversion was achieved in 22 (91.6%) and 23 (95.83%) patients before and after ibutilide administration, respectively. The amount of energy given was reduced from 13.89+/-11.44 to 8.28+/-9.64 joules (p=0.0001). Variables associated with the reduction of the defibrillation threshold after ibutilide administration were: duration of the last episode of atrial fibrillation (p=0.008), time since the first episode of atrial fibrillation (p=0.002), body mass index (p=0.01), ejection fraction (p=0.025), male gender (p=0.001), and diameter of the left atrium (p=0.028). Internal atrial defibrillation after ibutilide administration is a safe and effective method for sinus rhythm restoration, with concurrent significant reduction of the atrial defibrillation threshold.

  10. Fluid Replacement Monitoring: Effect of Dextran Overload, Norepinephrine Drip, and Positive Pressure Ventilation on Systemic Arterial, Right Atrial Pulmonary Wedge, and Left Atrial Pressures in Dogs

    Science.gov (United States)

    Hardy, James D.; Garcia, Jose B.; Hardy, Julia A.; Harkins, Mitchell H.

    1974-01-01

    The effects of dextran overload, norepinephrine drip and positive pressure ventilation upon right atrial, pulmonary wedge, left atrial and systemic arterial pressures were studied in 15 dogs. Rapid intravenous infusion of Dextran 70 invariably produced a marked and statistically significant (p < .001) rise in right atrial, pulmonary wedge and left atrial pressures. The rise in left atrial pressure invariably exceeded the rise in right atrial pressure, and the difference in maximum pressures averaged 10.8 mm Hg (p < .001). Thus acute fluid overload and pulmonary edema can be produced by rapid infusion of colloid solution in the absence of a marked rise in right atrial pressure, a point of considerable clinical importance. The rapid infusion of dextran produced a rise in systemic arterial blood pressure in all dogs so studied, though this rise was mild in some animals. This finding may explain in part the hypertension exhibited by patients in the recovery room who may have been overtransfused. A norepinephrine drip usually produced an increase in right atrial, wedge, left atrial and systemic arterial blood pressure (p < .01). When there was a significant rise in right atrial pressure and left atrial pressure, the maximum increase in left atrial pressure was always greater than the maximum increase in right atrial pressure (p < .005). This finding again emphasizes the fact that blood transfusion requirements cannot always be accurately assessed on the basis of right and left atrial pressure measurements when a vasopressor agent is being administered. Positive pressure ventilation increased both right and left atrial pressures, as expected. It was again confirmed that pulmonary wedge pressure, as measured with the Swan-Ganz catheter, is approximately equal to left atrial pressure over a wide range of induced variations. The Swan-Ganz catheter, introduced at the bedside in the intensive care unit when necessary, can provide highly useful information regarding left

  11. Pharmacologic Prevention of Incident Atrial Fibrillation: Long-Term Results From the ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial).

    Science.gov (United States)

    Dewland, Thomas A; Soliman, Elsayed Z; Yamal, Jose-Miguel; Davis, Barry R; Alonso, Alvaro; Albert, Christine M; Simpson, Lara M; Haywood, L Julian; Marcus, Gregory M

    2017-12-01

    Although atrial fibrillation (AF) guidelines indicate that pharmacological blockade of the renin-angiotensin system may be considered for primary AF prevention in hypertensive patients, previous studies have yielded conflicting results. We sought to determine whether randomization to lisinopril reduces incident AF or atrial flutter (AFL) compared with chlorthalidone in a large clinical trial cohort with extended post-trial surveillance. We performed a secondary analysis of the ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial), a randomized, double-blind, active-controlled clinical trial that enrolled hypertensive individuals ≥55 years of age with at least one other cardiovascular risk factor. Participants were randomly assigned to receive amlodipine, lisinopril, or chlorthalidone. Individuals with elevated fasting low-density lipoprotein cholesterol levels were also randomized to pravastatin versus usual care. The primary outcome was the development of either AF or AFL as diagnosed by serial study ECGs or by Medicare claims data. Among 14 837 participants without prevalent AF or AFL, 2514 developed AF/AFL during a mean 7.5±3.2 years of follow-up. Compared with chlorthalidone, randomization to either lisinopril (hazard ratio, 1.04; 95% confidence interval, 0.94-1.15; P=0.46) or amlodipine (hazard ratio, 0.93; 95% confidence interval, 0.84-1.03; P=0.16) was not associated with a significant reduction in incident AF/AFL. Compared with chlorthalidone, treatment with lisinopril is not associated with a meaningful reduction in incident AF or AFL among older adults with a history of hypertension. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00000542. © 2017 American Heart Association, Inc.

  12. Atrial Conduction Slows Immediately Before the Onset of Human Atrial Fibrillation

    Science.gov (United States)

    Lalani, Gautam G.; Schricker, Amir; Gibson, Michael; Rostamian, Armand; Krummen, David E.; Narayan, Sanjiv M.

    2012-01-01

    Objectives The aim of this study was to determine whether onset sites of human atrial fibrillation (AF) exhibit conduction slowing, reduced amplitude, and/or prolonged duration of signals (i.e., fractionation) immediately before AF onset. Background Few studies have identified functional determinants of AF initiation. Because conduction slowing is required for reentry, we hypothesized that AF from pulmonary vein triggers might initiate at sites exhibiting rate-dependent slowing in conduction velocity (CV restitution) or local slowing evidenced by signal fractionation. Methods In 28 patients with AF (left atrial size 43 ± 5 mm; n = 13 persistent) and 3 control subjects (no AF) at electrophysiological study, we measured bi-atrial conduction time (CT) electrogram fractionation at 64 or 128 electrodes with baskets in left (n = 17) or both (n = 14) atria during superior pulmonary vein pacing at cycle lengths (CL) accelerating from 500 ms (120 beats/min) to AF onset. Results Atrial fibrillation initiated in 19 of 28 AF patients and no control subjects. During rate acceleration, conduction slowed in 23 of 28 AF patients (vs. no control subjects, p = 0.01) at the site of AF initiation (15 of 19) or latest activated site (20 of 28). The CT lengthened from 79 ± 23 ms to 107 ± 39 ms (p < 0.001) on acceleration, in a spectrum from persistent AF (greatest slowing) to control subjects (least slowing; p < 0.05). Three patterns of CV restitution were observed: 1) broad (gradual CT prolongation, 37% patients); 2) steep (abrupt prolongation, at CL 266 ± 62 ms, 42%); and 3) flat (no prolongation, 21% AF patients, all control subjects). The AF initiation was more prevalent in patients with CV restitution (17 of 23 vs. 2 of 8; p = 0.03) and immediately followed abrupt reorientation of the activation vector in patients with broad but not steep CV restitution (p < 0.01). Patients with broad CV restitution had larger atria (p = 0.03) and were more likely to have persistent AF (p = 0

  13. [Identification of patients with atrial fibrillation using HRV parameters].

    Science.gov (United States)

    Kikillus, Nicole; Hammer, Gerd; Bolz, Armin

    2008-02-01

    Atrial fibrillation is the most common sustained cardiac rhythm disturbance. One of the most drastic complications is embolism, particularly stroke. Patients with atrial fibrillation have to be identified. This can lead to early therapy and thus avoiding strokes. The algorithm presented here detects atrial fibrillation securely and reliably. It is based on a single-channel ECG, which takes 60 min. First, the R-peaks are detected from the ECG and the RR interval is calculated. To be independent from pulse variations, the RR interval is normalized to 60 bpm. A parameter of heart rate variability is calculated in time domain (SDSD) and the so-called Poincaré plot is generated. The image analysis of the figures of the Poincaré plot is made automatically. The results from analysis in time domain, as well as image analysis, yield a risk level, which indicates the probability for the occurrence of atrial fibrillation. Even if there is no atrial fibrillation in the ECG while analyzing, it is possible to identify patients with atrial fibrillation. The sensitivity depends on the burden of atrial fibrillation. Even if a burden of 0% is assumed, the results still prove satisfactory (sensitivity of nearly 83%).

  14. Right Atrial Metastatic Melanoma with Unknown Primaries

    Directory of Open Access Journals (Sweden)

    Robin Kuriakose

    2015-01-01

    Full Text Available A 54-year-old male with history of anemia and rheumatoid arthritis presented with a three-month history of dyspnea on exertion and lower extremity edema. Patient was referred for a transthoracic echocardiogram that revealed a large right atrial mass with reduced ejection fraction of 40% and an incidental large liver mass. Subsequent cardiac MRI revealed a lobulated right atrial mass measuring 5.4 cm × 5.3 cm with inferior vena cava compression and adjacent multiple large liver lesions confirmed to be malignant melanoma through biopsy. Interestingly, no primaries were found in the patient. PET/CT imaging displayed hypermetabolic masses within the right atrium and liver that likely represent metastases, as well as bilateral pleural effusions, most likely due to heart failure. Preoperative coronary angiogram demonstrated perfusion to the mass by a dense network of neovasculature arising from the mid right coronary artery. The cardiac melanoma was surgically removed, and the right atrium was reconstructed with a pericardial patch. After surgery, all cardiac chambers appeared normal in size and function with associated moderate tricuspid regurgitation. The patient is currently being administered ipilimumab for systemic therapy of metastatic melanoma.

  15. Atrial tachycardia mimicking atrioventricular nodal reentry tachycardia.

    Science.gov (United States)

    Eilbert, Wesley P; Patel, Neal

    2013-07-01

    The term supraventricular tachycardia (SVT) is used to describe tachydysrhythmias that require atrial or atrioventricular nodal tissue for their initiation and maintenance. SVT can be used to describe atrioventricular nodal reentry tachycardia, atrioventricular reentry tachycardia, and atrial tachycardia (AT). AT is the least common of these SVT subtypes, accounting for only 10% of cases. Although the suggested initial management of each SVT subtype is different, they all can present with similar symptoms and electrocardiographic findings. Discuss the pathophysiology, diagnosis, and treatment of AT as compared with other types of SVT. We report a 56-year-old woman with symptoms and electrocardiographic findings consistent with SVT. Although standard treatment with intravenous adenosine failed to convert the SVT, it revealed AT as the cause of the tachydysrhythmia. The AT was successfully terminated with beta-blockade and the patient eventually underwent successful radioablation of three separate AT foci. AT frequently mimics other more common forms of SVT. AT might be recognized only when standard treatment of SVT has failed. Identification of AT in this setting is crucial to allow for more definitive therapy. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Atrial Fibrillation Predictors: Importance of the Electrocardiogram.

    Science.gov (United States)

    German, David M; Kabir, Muammar M; Dewland, Thomas A; Henrikson, Charles A; Tereshchenko, Larisa G

    2016-01-01

    Atrial fibrillation (AF) is the most common arrhythmia in adults and is associated with significant morbidity and mortality. Substantial interest has developed in the primary prevention of AF, and thus the identification of individuals at risk for developing AF. The electrocardiogram (ECG) provides a wealth of information, which is of value in predicting incident AF. The PR interval and P wave indices (including P wave duration, P wave terminal force, P wave axis, and other measures of P wave morphology) are discussed with regard to their ability to predict and characterize AF risk in the general population. The predictive value of the QT interval, ECG criteria for left ventricular hypertrophy, and findings of atrial and ventricular ectopy are also discussed. Efforts are underway to develop models that predict AF incidence in the general population; however, at present, little information from the ECG is included in these models. The ECG provides a great deal of information on AF risk and has the potential to contribute substantially to AF risk estimation, but more research is needed. © 2015 Wiley Periodicals, Inc.

  17. Clinical characteristics, management, and control of permanent vs. nonpermanent atrial fibrillation: insights from the RealiseAF survey.

    LENUS (Irish Health Repository)

    Murin, Jan

    2014-01-01

    Atrial fibrillation can be categorized into nonpermanent and permanent atrial fibrillation. There is less information on permanent than on nonpermanent atrial fibrillation patients. This analysis aimed to describe the characteristics and current management, including the proportion of patients with successful atrial fibrillation control, of these atrial fibrillation subsets in a large, geographically diverse contemporary sample.

  18. SHERLOCK 3CG™ Diamond Tip Confirmation System

    Science.gov (United States)

    2018-02-06

    Indication for Peripheral Intravenous Catheterization; Atrial Flutter; Premature Atrial Contraction; Premature Ventricular Contraction; Premature Junctional Contraction; Tachycardia; Atrioventricular Block; Bundle-Branch Block

  19. Optimization of Sensing and Feedback Control for Vibration/Flutter of Rotating Disk by PZT Actuators via Air Coupled Pressure

    Directory of Open Access Journals (Sweden)

    Bingfeng Ju

    2011-03-01

    Full Text Available In this paper, a feedback control mechanism and its optimization for rotating disk vibration/flutter via changes of air-coupled pressure generated using piezoelectric patch actuators are studied. A thin disk rotates in an enclosure, which is equipped with a feedback control loop consisting of a micro-sensor, a signal processor, a power amplifier, and several piezoelectric (PZT actuator patches distributed on the cover of the enclosure. The actuator patches are mounted on the inner or the outer surfaces of the enclosure to produce necessary control force required through the airflow around the disk. The control mechanism for rotating disk flutter using enclosure surfaces bonded with sensors and piezoelectric actuators is thoroughly studied through analytical simulations. The sensor output is used to determine the amount of input to the actuator for controlling the response of the disk in a closed loop configuration. The dynamic stability of the disk-enclosure system, together with the feedback control loop, is analyzed as a complex eigenvalue problem, which is solved using Galerkin’s discretization procedure. The results show that the disk flutter can be reduced effectively with proper configurations of the control gain and the phase shift through the actuations of PZT patches. The effectiveness of different feedback control methods in altering system characteristics and system response has been investigated. The control capability, in terms of control gain, phase shift, and especially the physical configuration of actuator patches, are also evaluated by calculating the complex eigenvalues and the maximum displacement produced by the actuators. To achieve a optimal control performance, sizes, positions and shapes of PZT patches used need to be optimized and such optimization has been achieved through numerical simulations.

  20. A roadmap to improve the quality of atrial fibrillation management : proceedings from the fifth Atrial Fibrillation Network/European Heart Rhythm Association consensus conference

    NARCIS (Netherlands)

    Kirchhof, Paulus; Breithardt, Guenter; Bax, Jeroen; Benninger, Gerlinde; Blomstrom-Lundqvist, Carina; Boriani, Giuseppe; Brandes, Axel; Brown, Helen; Brueckmann, Martina; Calkins, Hugh; Calvert, Melanie; Christoffels, Vincent; Crijns, Harry; Dobrev, Dobromir; Ellinor, Patrick; Fabritz, Larissa; Fetsch, Thomas; Freedman, S. Ben; Gerth, Andrea; Goette, Andreas; Guasch, Eduard; Hack, Guido; Haegeli, Laurent; Hatem, Stephane; Haeusler, Karl Georg; Heidbuechel, Hein; Heinrich-Nols, Jutta; Hidden-Lucet, Francoise; Hindricks, Gerd; Juul-Moeller, Steen; Kaeaeb, Stefan; Kappenberger, Lukas; Kespohl, Stefanie; Kotecha, Dipak; Lane, Deirdre A.; Leute, Angelika; Lewalter, Thorsten; Meyer, Ralf; Mont, Lluis; Muenzel, Felix; Nabauer, Michael; Nielsen, Jens C.; Oeff, Michael; Oldgren, Jonas; Oto, Ali; Piccini, Jonathan P.; Pilmeyer, Art; Potpara, Tatjana; Ravens, Ursula; Reinecke, Holger; Rostock, Thomas; Rustige, Joerg; Savelieva, Irene; Schnabel, Renate; Schotten, Ulrich; Schwichtenberg, Lars; Sinner, Moritz F.; Steinbeck, Gerhard; Stoll, Monika; Tavazzi, Luigi; Themistoclakis, Sakis; Tse, Hung Fat; Van Gelder, Isabelle C.; Vardas, Panagiotis E.; Varpula, Timo; Vincent, Alphons; Werring, David; Willems, Stephan; Ziegler, Andre; Lip, Gregory Y. H.; Camm, A. John

    2016-01-01

    At least 30 million people worldwide carry a diagnosis of atrial fibrillation (AF), and many more suffer from undiagnosed, subclinical, or 'silent' AF. Atrial fibrillation-related cardiovascular mortality and morbidity, including cardiovascular deaths, heart failure, stroke, and hospitalizations,

  1. Pulmonary edema following transcatheter closure of atrial septal defect

    Directory of Open Access Journals (Sweden)

    Keerthi Chigurupati

    2015-01-01

    Full Text Available We describe an incident of development of acute pulmonary edema after the device closure of a secundum atrial septal defect in a 52-year-old lady, which was treated with inotropes, diuretics and artificial ventilation. Possibility of acute left ventricular dysfunction should be considered after the defect closure in the middle-aged patients as the left ventricular compliance may be reduced due to increased elastic stiffness and diastolic dysfunction. Baseline left atrial pressure may be > 10 mmHg in these patients. Associated risk factors for the left ventricular dysfunction are a large Qp:Qs ratio, systemic hypertension, severe pulmonary hypertension and paroxysmal atrial fibrillation.

  2. Acute Pulmonary Edema Caused by a Giant Atrial Myxoma

    Directory of Open Access Journals (Sweden)

    Andrea Fisicaro

    2013-01-01

    Full Text Available Atrial myxoma is the most common primary cardiac tumor. Its clinical presentation spreads from asymptomatic incidental mass to serious life-threatening cardiovascular complications. We report the case of a 44-year-old man with evening fever and worsening dyspnea in the last weeks, admitted to our hospital for acute pulmonary edema. The cardiac auscultation was very suspicious for mitral valve stenosis, but the echocardiography revealed a huge atrial mass with a diastolic prolapse into mitral valve orifice causing an extremely high transmitral gradient pressure. Awareness of this uncommon acute presentation of atrial myxoma is necessary for timely diagnosis and prompt surgical intervention.

  3. Atrial natriuretic peptide and feeding activity patterns in rats

    Directory of Open Access Journals (Sweden)

    Oliveira M.H.A.

    1997-01-01

    Full Text Available This review presents historical data about atrial natriuretic peptide (ANP from its discovery as an atrial natriuretic factor (ANF to its role as an atrial natriuretic hormone (ANH. As a hormone, ANP can interact with the hypothalamic-pituitary-adrenal axis (HPA-A and is related to feeding activity patterns in the rat. Food restriction proved to be an interesting model to investigate this relationship. The role of ANP must be understood within a context of peripheral and central interactions involving different peptides and pathways

  4. Recent advances in the molecular pathophysiology of atrial fibrillation

    Science.gov (United States)

    Wakili, Reza; Voigt, Niels; Kääb, Stefan; Dobrev, Dobromir; Nattel, Stanley

    2011-01-01

    Atrial fibrillation (AF) is an extremely common cardiac rhythm disorder that causes substantial morbidity and contributes to mortality. The mechanisms underlying AF are complex, involving both increased spontaneous ectopic firing of atrial cells and impulse reentry through atrial tissue. Over the past ten years, there has been enormous progress in understanding the underlying molecular pathobiology. This article reviews the basic mechanisms and molecular processes causing AF. We discuss the ways in which cardiac disease states, extracardiac factors, and abnormal genetic control lead to the arrhythmia. We conclude with a discussion of the potential therapeutic implications that might arise from an improved mechanistic understanding. PMID:21804195

  5. Multimodality Cardiac Imaging for the Assessment of Left Atrial Function and the Association With Atrial Arrhythmias

    DEFF Research Database (Denmark)

    Olsen, Flemming Javier; Bertelsen, Litten; de Knegt, Martina Chantal

    2016-01-01

    an inverse relationship between LA reservoir function and degree of LA fibrosis. This has sparked an increased interest into the application of advanced imaging modalities, including both speckle tracking echocardiography and tissue tracking by cardiac magnetic resonance imaging. Even though increasing......Several cardiac imaging modalities are able to visualize the left atrium (LA) and, therefore, allow for quantification of both structural and functional properties of this cardiac chamber. In echocardiography, only the maximal LA volume is included in the assessment of diastolic function...... atrial fibrillation, which will be a point of focus in this review. Pivotal cardiac magnetic resonance imaging studies have revealed high correlation between LA fibrosis and risk of atrial fibrillation recurrence after catheter ablation, and subsequent multimodality imaging studies have uncovered...

  6. Atrial ectopy predicts late recurrence of atrial fibrillation after pulmonary vein isolation

    DEFF Research Database (Denmark)

    Gang, Uffe J O; Nalliah, Chrishan J; Lim, Toon Wei

    2015-01-01

    BACKGROUND: Late recurrence of atrial fibrillation (AF) after radiofrequency ablation remains significant. Asymptomatic recurrence poses a difficult clinical problem as it is associated with an equally increased risk of stroke and death compared with symptomatic AF events. Meta-analyses reveal th...... with a significantly increased risk of late AF recurrence. These results could have important clinical implications for the design of post-PVI follow-up. CLINICAL TRIAL REGISTRATION: URL: http://www.anzctr.org.au. Unique identifier: ACRTN12606000467538....

  7. Non-vitamin K antagonist oral anticoagulants versus warfarin for cardioversion of atrial fibrillation in clinical practice: A single-center experience.

    Science.gov (United States)

    Shibata, Naoki; Morishima, Itsuro; Okumura, Kenji; Morita, Yasuhiro; Takagi, Kensuke; Yoshida, Ruka; Nagai, Hiroaki; Tomomatsu, Toshiro; Ikai, Yoshihiro; Terada, Kazushi; Tsuzuki, Kazuhito; Tsuboi, Hideyuki; Sone, Takahito; Murohara, Toyoaki

    2017-02-01

    Anticoagulation therapy with the vitamin K antagonist (VKA) warfarin has been demonstrated to reduce thromboembolic risk after electrical cardioversion (ECV). However, data concerning ECV with non-VKA oral anticoagulants (NOACs) is limited. The objective of this study was to determine the efficacy and safety of NOACs in patients undergoing ECV in a real-world clinical practice at a single center in Japan. We retrospectively analyzed the data of 406 consecutive patients who underwent ECV for atrial fibrillation (AF) or flutter under anticoagulation with one of the three NOACs (n=149) or with a VKA (n=257). The CHADS2 and HAS-BLED scores were significantly higher in the VKA group, whereas the NOACs group had a tendency toward greater spontaneous echo contrast grades. After ECV, ischemic stroke occurred in three patients of the VKA group and one patient in the NOAC group, all of whom had persistent AF, indicating no significant difference in the thromboembolic event rate within 30 days following ECV. No other thromboembolic events, major bleeding, or death occurred in either group. Among the NOAC and VKA patients in whom we newly introduced an oral anticoagulant to perform ECV, the number of days leading to ECV was significantly lesser for the NOAC patients. NOACs may be used as an alternative to VKAs for ECV and may allow prompt ECV in clinical practices.

  8. Amiodarone and risk of death in contemporary patients with atrial fibrillation: Findings from The Retrospective Evaluation and Assessment of Therapies in AF study.

    Science.gov (United States)

    Ullal, Aditya J; Than, Claire T; Fan, Jun; Schmitt, Susan; Perino, Alexander C; Kaiser, Daniel W; Heidenreich, Paul A; Frayne, Susan M; Phibbs, Ciaran S; Turakhia, Mintu P

    2015-11-01

    There are limited data on mortality outcomes associated with use of amiodarone in atrial fibrillation and flutter (AF). We evaluated the association of amiodarone use with mortality in patients with newly diagnosed AF using complete data from the Department of Veterans Affairs national health care system. We included patients seen in an outpatient setting within 90 days of a new diagnosis for nonvalvular AF between Veterans Affairs fiscal years 2004 and 2008. Multivariate analysis and propensity-matched Cox proportional hazards regression were used to evaluate the association of amiodarone use to death. Of 122,465 patients (353,168 person-years of follow-up, age 72.1 ± 10.3 years, 98.4% males), amiodarone was prescribed in 11,655 (9.5%). Cumulative, unadjusted mortality rates were higher for amiodarone recipients than for nonrecipients (87 vs 73 per 1,000 person-years, P death was not modified by age, sex, heart failure, kidney function, β-blocker use, or warfarin use, but there was evidence of effect modification among patients diagnosed with AF as an inpatient versus outpatient. In a national health care system population of newly diagnosed AF, overall use of amiodarone as an early treatment strategy was not associated with mortality. Published by Elsevier Inc.

  9. Atrial arrhythmias after lung and heart-lung transplant: effects on short-term mortality and the influence of amiodarone.

    Science.gov (United States)

    Isiadinso, Ijeoma; Meshkov, Arnold B; Gaughan, John; Sandhu, Paul; Lim, Sharon; Cordova, Francis; Criner, Gerard

    2011-01-01

    The incidence and effect of atrial fibrillation or flutter (AF) after lung transplant are variable. An effect of pharmacologic treatment on outcomes is undetermined. One hundred thirty-seven consecutive lung or heart-lung transplant patients were reviewed retrospectively. Uni- and multivariate analyses were performed to determine statistically significant risk factors for AF and short-term mortality. AF occurred in 45.0% of patients within 26 days. By univariate analysis, male gender was predictive of AF (hazard ratio [HR] = 2.25, 95% confidence interval [CI] 1.21 to 4.20, p = 0.011). Mortality within 200 days occurred in 36 of 137 (22.6%) patients. Those with AF had higher mortality than those without AF (27 of 62 [43.5%] vs 9 of 75 [12%]; p amiodarone died, whereas 3 of 26 (11.5%) patients treated without amiodarone died (p amiodarone (9 of 75 [12%] vs 3 of 26 [11.5%], p = 1.00). By multivariate analysis, chronic obstructive pulmonary disease (HR = 0.395, CI 0.175 to 0.892, p = 0.025), primary pulmonary hypertension (HR = 7.245, CI 1.89 to 27.84, p = 0.0039), and use of amiodarone (HR = 2.967, CI 1.187 to 7.415, p = 0.020) were associated with death. Amiodarone was shown to be a significant statistical moderator (p amiodarone. In patients with severe lung pathology, amiodarone pulmonary toxicity may be more common than previously known, and may be a significant contributor to mortality. Amiodarone use should be restricted in the lung transplant patient population. Copyright © 2011 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  10. Prevalence and characteristics of left atrial tachycardia following left atrial catheter ablation.

    Science.gov (United States)

    Hashimoto, Toru; Tada, Hiroshi; Naito, Shigeto; Miyaji, Kohei; Yamada, Minoru; Tadokoro, Kazuyoshi; Kaseno, Kenichi; Oshima, Shigeru; Taniguchi, Koichi

    2007-01-01

    Left atrial tachycardia (AT) is a complication of left atrial catheter ablation (LACA) of atrial fibrillation (AF). However, its prevalence and characteristics have not been sufficiently clarified. We divided 121 patients who underwent LACA into 2 groups based on the results of AT occurrence after LACA (follow-up period; 12 +/- 7 months): an AT+ group and AT- group. New-onset left AT occurred in 30 patients (25%) 31 +/- 51 days after LACA. Among the 26 patients with an early onset of AT, 4 underwent a second ablation for AT, and 21 became free of AT within 6 months without a repeat ablation procedure. Among the 4 patients with a late onset of AT (> 2 months after the LACA), the tachycardia remitted without a repeat ablation procedure in a single patient within 6 months. Among 71 patients who underwent LACA with additional ablation lines, 22 (31%) developed new-onset left AT. Among 50 patients who underwent LACA alone, 8 (16%) developed new-onset left AT (P = 0.02). New-onset left AT is a frequent complication of LACA for AF, especially in men and in patients with a low left ventricular ejection fraction. Early (< 2 months) onset AT does not require a repeat ablation because it often represents a transient phenomenon and disappears spontaneously.

  11. A common data model to assess cardiovascular hospitalization and mortality in atrial fibrillation patients using administrative claims and medical records

    Directory of Open Access Journals (Sweden)

    Panaccio MP

    2015-01-01

    Full Text Available Mary P Panaccio,1 Gordon Cummins,2 Charles Wentworth,3 Stephan Lanes,4 Shannon L Reynolds,5 Matthew W Reynolds,3 Raymond Miao,1 Andrew Koren1 1US Medical Affairs, Sanofi, Bridgewater, NJ, USA; 2Health Engagement and Communications, Quintiles, Durham, NC, USA; 3Evidera, Lexington, MA, USA; 4HealthCore Inc., Andover, MA, USA; 5Comprehensive Health Insights, Louisville, KY, USA Purpose: Atrial fibrillation/flutter (AF is frequently associated with cardiovascular comorbidities. Observational health care databases are commonly used for research purposes in studies of quality of care, health economics, outcomes research, drug safety, and epidemiology. This retrospective cohort study applied a common data model to administrative claims data (Truven Health Analytics MarketScan® claims databases [MS-Claims] and electronic medical records data (Geisinger Health System's MedMining electronic medical record database [MG-EMR] to examine the risk of cardiovascular hospitalization and all-cause mortality in relation to clinical risk factors in recent-onset AF and to assess the consistency of analyses for each data source. Methods: Cohorts of patients with newly diagnosed AF (n=105,262 [MS-Claims] and n=3,919 [MG-EMR] and demographically similar patients without AF (n=105,262 [MS-Claims] and n=3,872 [MG-EMR] were followed from the qualifying AF diagnosis until cardiovascular hospitalization, death, database disenrollment, or study completion. A common data model standardized the data in structure, format, content, and nomenclature to allow for systematic assessment and comparison of outcomes from two disparate data sets. Results: In both databases, AF patients had greater overall baseline comorbidity and higher incidence rates of cardiovascular hospitalization (threefold higher and all-cause mortality (46% higher than non-AF patients. For AF patients, incidence rates of cardiovascular hospitalization and all-cause mortality were increased by the concomitant

  12. Rapid slowing of the atrial fibrillatory rate after administration of AZD7009 predicts conversion of atrial fibrillation

    DEFF Research Database (Denmark)

    Aunes, Maria; Egstrup, Kenneth; Frison, Lars

    2014-01-01

    BACKGROUND: Effects on the atrial fibrillatory rate (AFR) were studied during infusion with the combined potassium and sodium channel blocker AZD7009. METHODS AND RESULTS: Patients with persistent atrial fibrillation (AF) were randomized to AZD7009 or placebo. Thirty-five patients converted to si...... fpm (p=0.02), and at 10 min, -133 vs. -111 fpm (p=0.048). The AFR-SD and the exponential decay decreased. A small left atrial area was the only baseline predictor of conversion to SR. CONCLUSIONS: AZD7009 produced a significantly more rapid decrease of the AFR in converters than in non...

  13. Dronedarone in high-risk permanent atrial fibrillation

    DEFF Research Database (Denmark)

    Connolly, Stuart J; Camm, A John; Halperin, Jonathan L

    2011-01-01

    Dronedarone restores sinus rhythm and reduces hospitalization or death in intermittent atrial fibrillation. It also lowers heart rate and blood pressure and has antiadrenergic and potential ventricular antiarrhythmic effects. We hypothesized that dronedarone would reduce major vascular events in ...

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

    DEFF Research Database (Denmark)

    Risom, Signe S.; Zwisler, Ann-Dorthe; Johansen, Pernille P.

    2017-01-01

    Background: Exercise-based cardiac rehabilitation may benefit adults with atrial fibrillation or those who had been treated for atrial fibrillation. Atrial fibrillation is caused by multiple micro re-entry circuits within the atrial tissue, which result in chaotic rapid activity in the atria....... Objectives: To assess the benefits and harms of exercise-based rehabilitation programmes, alone or with another intervention, compared with no-exercise training controls in adults who currently have AF, or have been treated for AF. Search methods: We searched the following electronic databases; CENTRAL...... and the Database of Abstracts of Reviews of Effectiveness (DARE) in the Cochrane Library, MEDLINE Ovid, Embase Ovid, PsycINFO Ovid, Web of Science Core Collection Thomson Reuters, CINAHL EBSCO, LILACS Bireme, and three clinical trial registers on 14 July 2016. We also checked the bibliographies of relevant...

  15. A giant right atrial myxoma with pulmonary arterial hypertension.

    Science.gov (United States)

    Zairi, Ihsen; Mzoughi, Khadija; Jnifene, Zouhayer; Fennira, Sana; Ben Moussa, Fathia; Kammoun, Sofiene; Dhiab, Mohamed Mounir; Kraiem, Sondos

    2015-01-01

    Here we report a case of a right atrial mass that morphology mimicking myxoma, in a young patient with no past medical history. The mass was pathologically confirmed to be symptomatic and surgical removal was successfully done.

  16. Dabigatran use in Danish atrial fibrillation patients in 2011

    DEFF Research Database (Denmark)

    Sørensen, Rikke; Gislason, Gunnar; Torp-Pedersen, Christian Tobias

    2013-01-01

    Objective: Dabigatran was recently approved for anticoagulation in patients with atrial fibrillation (AF); data regarding real-world use, comparative effectiveness and safety are sparse. Design: Pharmacoepidemiological cohort study. Methods/settings: From nationwide registers, we identified patie...

  17. Dronedarone in high-risk permanent atrial fibrillation

    DEFF Research Database (Denmark)

    Connolly, Stuart J; Camm, A John; Halperin, Jonathan L

    2011-01-01

    Dronedarone restores sinus rhythm and reduces hospitalization or death in intermittent atrial fibrillation. It also lowers heart rate and blood pressure and has antiadrenergic and potential ventricular antiarrhythmic effects. We hypothesized that dronedarone would reduce major vascular events...

  18. Who Is at Risk for Atrial Fibrillation (AF or AFib)?

    Science.gov (United States)

    ... Anyone with heart disease, including valve problems , hypertrophic cardiomyopathy , acute coronary syndrome , Wolff-Parkinson-White (WPW) syndrome and history of heart attack . Additionally, atrial fibrillation is the most common complication after heart surgery. Drinking alcohol Binge drinking (having ...

  19. YKL-40 levels and atrial fibrillation in the general population

    DEFF Research Database (Denmark)

    Marott, Sarah C W; Benn, Marianne; Johansen, Julia S

    2013-01-01

    BACKGROUND: Atrial fibrillation is associated with inflammation. In contrast to inflammatory markers like C-reactive protein (CRP) and fibrinogen produced in the liver, YKL-40 is produced at the site of inflammation including in the myocardium. We hypothesized that elevated plasma YKL-40 levels a...... individuals from the cross-sectional Copenhagen General Population Study including 337 cases with atrial fibrillation. A YKL-40 level >95% percentile (>204μg/L) versus 95% percentile versus...... associate with increased risk of atrial fibrillation. METHOD AND RESULTS: We measured plasma YKL-40 in 8731 participants from the prospective Copenhagen City Heart Study including 896 individuals who developed atrial fibrillation during up to 18years of follow-up. Additionally, we measured YKL-40 in 6621...

  20. 50. Successful percutanous closure of spiral atrial septal defect

    Directory of Open Access Journals (Sweden)

    Mashail Abdulaziz Alobaidan

    2015-10-01

    An unusual morphology of atrial septal defect has been described where there is an apparently “double atrial septum” (Roberson, 2006. The terminology around this lesion has been attributed to be the wide separation of the primary atrial septum (primum septum from the secondary septum (septum secundum and the “spiral” spatial arrangement of the margins of the atrial septal defect (ASD has led to the term spiral ASD to describe this arrangement. This has been described to be associated with a high risk of device embolization or technical failure in the placement of an occluder device. We report the echocardiographic findings and outcome of a patient with this form of ASD in whom percutaneous occlusion was successful of which is considered up to date to be the first successful closure of this type of ASD.