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 ...
Pozen, R G; Pastoriza, J; Rozanski, J J; Kessler, K M; Myerburg, R J
Eighteen male patients (mean age 59 years) who were electrically cardioverted for pure atrial flutter were retrospectively studied to determine those factors influencing the maintenance of regular sinus rhythm or reversion to atrial flutter. Six months after successful cardioversion, 10 patients (55%) had recurrent atrial flutter and eight patients (45%) were still in sinus rhythm. The two groups were not significantly different with respect to age, symptomatology, abnormalities on the 12 lea...
Murthy, Avinash M A; Jain, Ankit; Tan, Henry
A 1:1 conduction of atrial tachyarrhythmias, although not uncommon, usually is associated with the use of antiarrhythmic drugs; hyperthyroidism etc. Spontaneous 1:1 conduction of atrial flutter is indeed rare. We present a case of a spontaneous 1:1 conduction of a cavotricuspid isthmus-dependent atrial flutter.
Objective: To evaluate the radiofrequency catheter ablation for type I atrial flutter through application of Holo catheter labelling with anatomic imaging localization to ablate the isthmus of IVCTA during complete double-way block. Methods: Eleven cases with type I atrial flutter undergone Holo catheter labelling technique and consecution with conduction time change of coronary venous sinus orifice with-right atrial lower lateral wall pace excitation, were performed with radiofrequency catheter ablation for the isthmus outcoming with complete double-way conduction block. Results: All together 11 cases with 4 of atrial flutter and 7 of sinus rhythm were undergone radiofrequency catheter ablation resulting with double-way conduction block of the isthmus accompanied by prolongation of right atrial conduction time 56.0 ± 2.3 ms and 53.0 ± 4.6 ms respectively. The right atrial excitation appeared to be in clockwise and counter-clockwise of single direction. No recurrence occurred during 3-34 months follow up with only one showing atrial fibrillation. Conclusions: The application of Holo catheter labelling technique with anatomic imaging localization to achieve the double-way conduction block by radiofrequency catheter ablation of TVC-TA isthmus, is a reliable method for treating atrial flutter
Camm, J; Ward, D.; Spurrell, R
Ten patients who suffered spontaneous paroxysms of atrial flutter were investigated by electrophysiological techniques. Two had overt Wolff-Parkinson-White syndrome; three Lown-Ganong-Levine syndrome; and one a concealed accessory atrioventricular connection. Atrial flutter was initiated, at study, by right atrial pacing and electrograms from the right atrium and coronary sinus were observed for at least five minutes to ensure stable flutter in both atria. Atrial flutter was terminated by 2.5...
van den Berg, M.P.; Crijns, H J; Szabó, B. M.; Brouwer, J.; Lie, K.I.
OBJECTIVE--To examine the effect of exercise on cycle length in atrial flutter. PATIENTS--15 patients with chronic atrial flutter. Seven patients were taking digoxin and six verapamil; two were not taking medication. METHODS--All patients underwent bicycle ergometry. Flutter cycle length was measured at rest and at peak exercise. RESULTS--Mean flutter cycle length increased from 245 ms to 256 ms (P = 0.002). Six patients developed 1:1 atrioventricular conduction. Significant increases in flut...
Reinder Evertz MD; Juan Acosta MD; David Andreu M.Sc; Josep Brugada MD, PhD; Lluis Mont MD, PhD
Full Text Available A 55-year-old male was referred for a third ablation procedure because of recurrent atrial fibrillation. During re-isolation of the inferior right pulmonary vein the patient developed an atypical flutter with an clockwise activation pattern around the mitral annulus. Linear ablation at the left mitral isthmus transformed but did not terminate the tachycardia. The cavotricuspid isthmus proved to be a second critical isthmus and linear ablation at this site terminated the tachycardia.
Aim. Atrial fibrillation (AFib) is a major clinical issue and its occurrence is the main problem after catheter ablation of atrial flutter. The long-term occurrence of AFib after common atrial flutter ablation is still matter of debate as it may influence the therapeutic approach. So, the aim of our study was to analyze the determinants and the time course of AFib after radiofrequency catheter ablation of chronic common atrial flutter. Methods and Results. 89 consecutive patients (67.5 ± ...
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 st...
Robertson, C E; Miller, H C
A 59-year-old man presented with atrial flutter and a 2:1 atrioventricular response, which, after intravenous disopyramide, became 1:1. A mechanism of slowed atrial flutter rate and improved atrioventricular nodal conduction, similar to that recognised with quinidine, is suggested.
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.
Atrial flutter is a common arrhythmia that may cause significant symptoms, including palpitations, dyspnea, chest pain and even syncope. Frequently it’s possible to diagnose atrial flutter with a 12-lead surface ECG, looking for distinctive waves in leads II, III, aVF, aVL, V1,V2. Puech and Waldo developed the first classification of atrial flutter in the 1970s. These authors divided the arrhythmia into type I and type II. Therefore, in 2001 the European Society of Cardiology and the North Am...
Hirata, K.; Kato, H.; Yoshioka, F; Matsunaga, T
Fetal supraventricular tachycardia may cause congestive heart failure, hydrops fetalis, and intrauterine death. Tachycardia in a fetus of 34 weeks' gestation was diagnosed as atrial flutter by echocardiography, and was successfully treated by giving the mother digoxin.
Wilson, N.; Forfar, J D; Godman, M J
We report a case of isolated atrial flutter in a neonate, attributable to maternal lithium treatment, and suggest that the assessment of all infants born to mothers on lithium treatment during pregnancy should include an electrocardiogram.
Livio Dei Cas
Full Text Available Atrial flutter is a common arrhythmia that may cause significant symptoms, including palpitations, dyspnea, chest pain and even syncope. Frequently it’s possible to diagnose atrial flutter with a 12-lead surface ECG, looking for distinctive waves in leads II, III, aVF, aVL, V1,V2. Puech and Waldo developed the first classification of atrial flutter in the 1970s. These authors divided the arrhythmia into type I and type II. Therefore, in 2001 the European Society of Cardiology and the North American Society of Pacing and Electrophysiology developed a new classification of atrial flutter, based not only on the ECG, but also on the electrophysiological mechanism. New developments in endocardial mapping, including the electroanatomical 3D mapping system, have greatly expanded our understanding of the mechanism of arrhythmias. More recently, Scheinman et al, provided an updated classification and nomenclature. The terms like common, uncommon, typical, reverse typical or atypical flutter are abandoned because they may generate confusion. The authors worked out a new terminology, which differentiates atrial flutter only on the basis of electrophysiological mechanism. (Heart International 2006; 3-4: 161-70
Laurent, Valérie; Fauchier, Laurent; Pierre, Bertrand; Grimard, Caroline; Babuty, Dominique
Although cavotricuspid isthmus radiofrequency catheter ablation is considered curative therapy for typical atrial flutter, many patients develop an atrial fibrillation after ablation. The purpose of our study was to determine the incidence and the predictive factors of post-ablation atrial fibrillation. One hundred and forty eight consecutive patients underwent cavotricuspid isthmus ablation for the treatment of typical atrial flutter between January 2004 and December 2005 in our electrophysiological department. Complete cavotricuspid isthmus block was successfully obtained in 96.6% of the patients. At the end of the electrophysiological study a sustained atrial fibrillation was inducible in 20 patients (13.5%). During an average follow-up of 21.3 +/- 8.2 months, atrial fibrillation occurred in 27% of the patients. Univariate analysis identified four parameters correlated with post-ablation atrial fibrillation among the 21 parameters tested: the young age of the patients, a prior history of atrial fibrillation, an inducible atrial fibrillation, and a paroxysmal atrial flutter. Only inducible atrial fibrillation and paroxysmal atrial flutter were independent factors linked to atrial fibrillation after ablation. In our study the incidence of atrial fibrillation after cavotricuspid isthmus radiofrequency catheter ablation is 152 per 1,000 patient-years, i.e. 25 times higher than the incidence of atrial fibrillation in the general population of the same age. Twenty five percent of the patients who had neither prior history of atrial fibrillation nor structural heart disease suffered from atrial fibrillation during a mean follow-up of 21.3 +/- 8.2 months. All these results suggest that atrial flutter and fibrillation could be manifestations of a more general electrophysiologic disease. They emphasize the need for all these patients to benefit from regular, long-term cardiological follow-up after cavotricuspid isthmus ablation because of the high incidence of atrial
We report a successful electrical cardioversion of a foetal atrial flutter (AFL) immediately post delivery. We describe the diagnostic tools, assessment and the management antenatally. Then, we review the literature and discuss the debate about management. We stress the point that if the flutter wave is not progressing, the foetal heart will tolerate till term and we can try electrical cardioversion with confidence after delivery.
Clementy, Nicolas; Desprets, Laurent; Pierre, Bertrand; Lallemand, Bénédicte; Simeon, Edouard; Brunet-Bernard, Anne; Babuty, Dominique; Fauchier, Laurent
Similar predisposing factors are found in most types of atrial arrhythmias. The incidence of atrial fibrillation (AF) among patients with atrial flutter is high, suggesting similar outcomes in patients with those arrhythmias. We sought to investigate the long-term outcomes and prognostic factors of patients with AF and/or atrial flutter with contemporary management using radiofrequency ablation. In an academic institution, we retrospectively examined the clinical course of 8,962 consecutive patients admitted to our department with a diagnosis of AF and/or atrial flutter. After a median follow-up of 934 ± 1,134 days, 1,155 deaths and 715 stroke and/thromboembolic (TE) events were recorded. Patients with atrial flutter undergoing cavotricuspid isthmus ablation (n = 875, 37% with a history of AF) had a better survival rate than other patients (hazard ratio [HR] 0.35, 95% confidence interval [CI] 0.25 to 0.49, p <0.0001). Using Cox proportional hazards model and propensity score model, after adjustment for main other confounders, ablation for atrial flutter was significantly associated with a lower risk of all-cause mortality (HR 0.55, 95% CI 0.36 to 0.84, p = 0.006) and stroke and/or TE events (HR 0.53, 95% CI 0.30 to 0.92, p = 0.02). After ablation, there was no significant difference in the risk of TE between patients with a history of AF and those with atrial flutter alone (HR 0.83, 95% CI 0.41 to 1.67, p = 0.59). In conclusion, in patients with atrial tachyarrhythmias, those with atrial flutter with contemporary management who undergo cavotricuspid isthmus radiofrequency ablation independently have a lower risk of stroke and/or TE events and death of any cause, whether a history of AF is present or not. PMID:25200340
Lukac, Peter; Hjortdal, Vibeke E; Pedersen, Anders K;
congenital heart disease. Coronary angiography and electrophysiology study using an electroanatomic mapping system to assess the conduction across the line and to try to induce atrial flutter were performed three months after the operation in 15 patients. RESULTS: Eleven patients had bidirectional block in...... patient with bidirectional block and all patients without bidirectional block had inducible or spontaneous atrial flutter (p = 0.0007). No lesion of the right coronary artery was detected at coronary angiography. CONCLUSIONS: The success rate was suboptimal and the intervention is potentially...
Christiansen, Christine Benn; Torp-Pedersen, Christian; Køber, Lars
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....
Cabrera Rodríguez, José Ángel; Ho, Siew Yen; Sánchez-Quintana, Damián
Although most ablative procedures undertaken for common atrial flutter target the inferior right atrial isthmus, comparative studies of the morphology of this area are lacking. Our study examines its angiographic anatomy, making correlations with postmortem specimens, to provide a better understanding of the anatomic substrate of this arrhythmia. The gross morphological features and dimensions of the area between the orifice of the inferior caval vein and the attachment of the septal leafl...
Yu. A. Bunin
Full Text Available Diagnosis and treatment of atrial flutter (AF is an important clinical task. Epidemiological data, electrophysiological mechanisms and updated classification of AF are presented as well as treatment algorithm that is suggested by leading experts. Two strategies of AF therapy are shown: "rhythm control" and "rate control". Author paid attention that ventricular rate reduction in AF is more difficult task than this in atrial fibrillation. Indications for different AF treatments are discussed: pharmacotherapy, pacing and cardioversion as well as surgical methods.
Till, J; WREN, C.
OBJECTIVE--To highlight the association between atrial flutter and accessory connections in the fetus and young infant. DESIGN--A retrospective review from January 1985 to January 1990. PATIENTS--Fetuses, neonates, and young infants with atrial flutter. RESULTS--Four fetuses and five infants presented with atrial flutter. In two fetuses and one infant sinus rhythm returned spontaneously. The other six required cardioversion. Three of them developed orthodromic atrioventricular re-entry tachyc...
O'Callaghan, P.; Meara, M; Kongsgaard, E; Poloniecki, J.; Luddington, L; Foran, J; Camm, A; Rowland, E; Ward, D.
OBJECTIVE—To assess the changes in quality of life, arrhythmia symptoms, and hospital resource utilisation following catheter ablation of typical atrial flutter. DESIGN—Patient questionnaire to compare the time interval following ablation with a similar time interval before ablation. SETTING—Tertiary referral centre. PATIENTS—63 consecutive patients were studied. Four patients subsequently underwent an ablate and pace procedure, two died of co-morbid illnesses, and two were lost to follow up....
Francisco Theogenes Macêdo Silva
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.
Deborah Wolbrette, Deborah
Deborah Wolbrette, Mario Gonzalez, Soraya Samii, Javier Banchs, Erica Penny-Peterson, Gerald NaccarelliPenn State Heart and Vascular Institute, Penn State Milton S Hershey Medical Center, Hershey, Pennsylvania, USAAbstract: Dronedarone, a new Class III antiarrhythmic agent, has now been approved by the US Food and Drug Administration for use in patients with atrial fibrillation or atrial flutter. Approval came in March 2009 due to the positive results of the ATHENA trial showing significant r...
Gavrilyuk, O.; Boeva, Y.; Anyasi, I.; Maltseva, M.; Volkov, D.
Clinical case of persistent atrial flutter in combination with comorbid pathology is presented. Clinical diagnosis, choice of optimal interventional and drug therapy are discussed. Catheter ablation was considered as the optimal method for radical treatment of the atrial flutter. A modification of drug therapy is required according to the condition of the patient after the catheter ablation.
Dewland, Thomas A.; Glidden, David V.; Marcus, Gregory M
Atrial flutter ablation is associated with a high rate of acute procedural success and symptom improvement. The relationship between ablation and other clinical outcomes has been limited to small studies primarily conducted at academic centers. We sought to determine if catheter ablation of atrial flutter is associated with reductions in healthcare utilization, atrial fibrillation, or stroke in a large, real world population. California Healthcare Cost and Utilization Project databases were u...
J. Lin; Lai, L; Lin, L.; Tseng, Y; Lien, W; Huang, S.
Objective—To investigate the electrophysiological determinant underlying the electrical induction of counterclockwise and clockwise isthmus dependent atrial flutter. Patients and methods—The isthmus bordered by the inferior vena caval orifice-tricuspid annulus-coronary sinus ostium (IVCO-TA-CSO) has been assumed to be the site of both slow conduction and unidirectional block critical to the initiation of atrial flutter. Trans-isthmus and the global atrial conduction were studied in 25 patient...
Typical atrial flutter and atrial fibrillation are frequently observed to coexist(1) . In the current context of interventional electrophysiology, curative or at least definitive ablation is available for both arrhythmias. Despite their coexistence, it is not clear whether typical flutter ablation is necessary in all patients undergoing catheter ablation of atrial fibrillation. The following review explores the pathophysiology of both arrhythmias, their interrelationships and the availa...
Eduardo Dytz Almeida; Raphael Boesche Guimarães; Laura Siga Stephan; Alexandre Kreling Medeiros; Katia Foltz; Roberto Tofani Santanna; Leonardo Martins Pires; Marcelo Lapa Kruse; Gustavo Glotz de Lima; Tiago Luiz Luz Leiria
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 medic...
Full Text Available Typical atrial flutter and atrial fibrillation are frequently observed to coexist(1 . In the current context of interventional electrophysiology, curative or at least definitive ablation is available for both arrhythmias. Despite their coexistence, it is not clear whether typical flutter ablation is necessary in all patients undergoing catheter ablation of atrial fibrillation. The following review explores the pathophysiology of both arrhythmias, their interrelationships and the available data pertaining to this theme.
Lai, L; J. Lin; Lin, L.; Chen, W.; Ho, Y.; Tseng, Y; Chen, C.; Y. Lee; Lien, W; Huang, S.
Objective—To develop new electrocardiographic (ECG) criteria for the differentiation between counterclockwise and clockwise atrial flutters. Background—Traditionally, the ECG differentiation between counterclockwise and clockwise atrial flutters is based on the flutter wave polarity in the inferior leads. However, determination of flutter wave polarity is subjective and sometimes difficult, especially in flutter waves of undulating pattern. Patients—The study comprised 37 consecutive patient...
Eduardo Dytz Almeida
Full Text Available 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.
Lu chunshan; Liu Xingpeng; Dong Jianzeng; Ma Changsheng
Objectives There are two kind of atrial flutter during circumferential ablation for atrial fibrillation (AF): new onset left atrial flutter (LAFL), with a history of atrial flutter (AFL). What is the relationship of AFL and AF? Whether there are some differences in clinical course and mechanism between the new onset LAFL and the with a history of AFL remained unclear. The aim of this study was to assess the impacts of circumferential ablation on the occurrence of arrhythmias in follow-up in 2 groups:( 1 ) patients with a history of AFL and AF, and (2)patients with new onset LAFL. Methods Data from 465 patients who had circumferential pulmonary vein ablation (CPVA) or segmental pulmonary vein ablation (SPVA) were analyzed. Patients with a history of AFL ablation and patients who had concomitant AFL ablation were included from analysis. Forty-one patients constituted the history of AFL group (group 1, aged 57±13 years, 7 females) and twenty-eight patients constituted the new onset LAFL group (group 2, aged 55±12 years, 6 females). bipolar recordings were obtained from the tricuspid annulus, coronary sinus,interatrial septum and left atrium. Target sites were identified by early, fragmented or double potentials and by concealed entrainment. Linear lesions were created between target sites and nearby anatomical barriers (1) typical atrial flutter (cycle length, 242±39 ms). cavotricuspid isthmus ablation was performed.(2) new onset LAFL (cycle length, 282±153 ms). 20 episodes of AAFs were documented in 20/28 (71.4%)patients. Target sites were identified around pulmonary veins (n=10), gap in linear lesion (n=7), left atrial roof lines (1 case). For those cases the ablation line between PV and mitral annulus was performed.Patients in Group 2 had larger left atria, higher incidence of AFL pre-CPVA, and lower ejection fraction. Results There was no significant difference in post-CPVA AF recurrence between Groups 1 and 2, but AFL incidence after CPVA was higher in Group
Vaduganathan, Muthiah; Auslander, Joel N.
We present an 89-year-old woman with newly diagnosed atrial flutter associated with a flare of her rheumatoid arthritis (RA). She had a history of diet-controlled type 2 diabetes mellitus, hypertension, and RA and presented with lightheadedness and worsening hand pain. She was found to be in new atrial flutter with rapid ventricular response and to have an active RA flare. In addition to adequate atrial flutter rate control, her RA flare was managed by adding hydroxychloroquine and doubling h...
Nabar, A; Rodriguez, L.; Timmermans, C; van Mechelen, R; Wellens, H
OBJECTIVE—To describe the electrocardiographic and electrophysiological findings of new atrial flutter developing in patients taking class IC antiarrhythmic drugs for recurrent atrial fibrillation, and to report the long term results of right atrial isthmus ablation in relation to the ECG pattern of spontaneous atrial flutter. DESIGN—Retrospective analysis. SETTING—Tertiary care academic hospital. PATIENTS—24 consecutive patients with atrial fibrillation (age 54 (12) years; 5 female, 19 male)...
O'Núnáin, S; Linker, N J; Sneddon, J. F.; Debbas, N M; Camm, A J; Ward, D E
OBJECTIVE--To assess the effects of low energy ablation of the substrate for atrial flutter. DESIGN--Initial retrospective analysis of patients undergoing low energy ablation of the atrioventricular node for refractory atrial flutter (group 1) was followed by a prospective assessment of low energy ablation in the posterio-inferior right atrium for the same condition (group 2). SETTING--Tertiary referral centre for management of cardiac arrhythmias. PATIENTS--Seven men (aged 50-67 years) with ...
Won, H. S.; Lee, I. S.; Yoo, H. K.; Yoo, S. J.; Ko, J K; Lee, P R; A. Kim; Mok, J. E.
We describe two cases of fetal atrial flutter associated with severe fetal hydrops which were unresponsive to digoxin but were successfully treated with flecainide acetate. Two cases of fetal atrial flutter were identified in fetuses with severe fetal hydrops on 3rd trimester ultrasonogram(28 weeks' gestation and 30 weeks' gestation). Following failed digoxin monotherapy, flecainide acetate was added to digoxin. On the 7th day and 13th day after combined therapy, fetal heart rate converted to...
Full Text Available This study aimed to elaborate the electrophysiology characteristics and radiofrequency ablation (RFA results of atrial flutter (AFL which has not been established in Indonesia. Three multipolar catheters were inserted percutaneously and positioned into coronary sinus (CS, His bundle area and around tricuspid annulus. Eight mm ablation catheter was used to make linear ablation at CTI of typical and reverse typical AFL. Bidirectional block was confirmed by conduction time prolongation of more than 90 msec from low lateral to CS ostium and vice versa, and/or by means of differential pacing. Thirty AFL from 27 patients comprised of 19 typical AFL, 5 reverse typical AFL and 6 atypical AFL enrolled the study. Mean tachycardia cycle length (TCL were 261.8 ± 42.84, 226.5 ± 41.23, and 195.4 ± 9.19 msec, respectively (p = 0.016. CTI conduction time occupied up to 60% of TCL with mean conduction time of 153.0 ± 67.37 msec. CS activation distributed to three categories which comprised of proximal to distal, distal to proximal and fusion activation. Only nine of 27 patients had no structural heart disease. RFA of symptomatic typical and reverse typical AFL demonstrated 96% success and 4.5 % recurrence rate during 13 ± 8 months follow up. Typical AFL is the predominant type of AFL in our population. The majority of AFL cases suffered from structural heart disease. RFA was highly effective to cure typical and reverse typical AFL. (Med J Indones 2007; 16:151-8 Keywords: atrial flutter, electrophysiology, ablation
First-harmonic Fourier analysis of a gated blood-pool study is based on the assumption that the cardiac chambers contract once per cardiac cycle. In atrial arrhythmias this condition may not exist for the atria. We recently studied a patient with atrial flutter and 2:1 artioventricular conduction. There were predictable alterations in the first-harmonic Fourier phase and amplitude images. The observed changes from first-harmonic Fourier analysis were: (a) very low atrial amplitude values, and (b) absence of identifiable atrial regions on the phase image
VANGELDER, IC; CRIJNS, HJ; VANDERLAARSE, A; VANGILST, WH; LIE, KI
To study the incidence and clinical significance of postshock ST segment elevations, we recorded 12-lead ECGs immediately after transthoracic direct-current electrical cardioversion in 146 patients with atrial fibrillation or flutter. Among 23 patients (19%), acute ST segment elevations amounted to
Anderson, K. J.; Simmons, S. C.; Hallidie-Smith, K A
A case of antepartum atrial tachyarrhythmia was detected in the 36th week of pregnancy. Cardiotocograph recordings done twice daily enabled close surveillance of the fetal condition after oxytoxin challenge testing had failed to show evidence of hypoxia. After a diagnosis of fetal cardiac arrhythmia had been made, elective caesarean section in the 40th week of pregnancy resulted in delivery of an infant in atrial flutter and cardiac failure. Both these problems were soon resolved by cardiover...
郑方胜; 祁学文; 刘海峰; 康宁宁
Objective To determine the feasibility and efficiency of terminating atrial flutter (AFL) and atrial fibrillation (AF) using synchronous low-energy shocks delivered through a novel transesophageal electric balloon electrode system.Methods By using a novel electric balloon electrode system, we attempted 91 transesophageal cardioversions in 52 patients, to treat 53 episodes of AFL and 38 episodes of AF.Results Of the 40 patients of AFL that failed to respond to drug therapy, 37 (92.5%) were successfully countershocked to sinus rhythm by transesophageal cardioversion, with a mean energy of (22.70±4.50) J (20-30 J). Of the 19 patients in AF, transesophageal cardioversion was successful in 16 (84.2%) cases, requiring a mean delivered energy of (17.38±8.58) J (3-30 J). There were no complications such as heart block or ventricular fibrillation, and no evidence of esophageal injury. Conclusions Transesophageal cardioversion using an electric balloon electrode system is an effective and feasible method for the treatment of AFL and AF. It requires low energy and no anesthesia, leads to less trauma, and shows a high cardioversion success rate that may prove valuable in the management of tachyarrhythmias.
Ramsdale, D. R.; Peterson, C
Combined rapid atrial flutter/fibrillation and recurrent ventricular tachycardia occurred in an 82 year old man with acute myocardial infarction. Both arrhythmias were promptly terminated by intravenous sotalol, suggesting another use for this unique drug in the absence of hypotension, heart block or cardiac failure.
Pedersen, O D; Bagger, H; Køber, L;
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...... 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...
Objective: To evaluate the influnce of atrial fibrillation(AF)/atrial flutter on the mortality and prognosis of patients with AMI. Methods: A total of 297 consecutive patients were studied from Jan. 2001 to Dec. 2005 and were categorized into 2 groups according to the presence or absence of AF/atrial flutter. The 30 d and 6 mo mortalities, Killip Grades, cardiogenic shock, arrhythmia and left ventricular ejectory functional (LVEF) 6 months after AMI with Doppler US between the 2 groups were compared. Results: The incidence of AF/atrial fluttler was 12.5% with older age, higher Killip Gorade, higher CPK peak, higher rates of previous myocardial infarction and multivascular involvement than those without AF/ atrial flutter. The short and medium-term mortalities in AF/atriat flutter group were both significantly higher than those of non-AF/atrial flutter group (P<0.05). Conclusions: The short and medium-term mortalities increase obviously in AMI complicated with AF/atrial flutter, probably related to the severity of atherosclerosis. (authors)
Frost, L.; Frost, P.; Vestergaard, P.
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 diagnosis (inpatient as well as outpatient) of atrial fibrillation or flutter was examined.
A.S. Thornton (Andrew); P. Janse (Petter); M. Alings (Marco); M.F. Scholten (Marcoen); J.M. Mekel; M. Miltenburg (Max); E. Jessurun; L.J.L.M. Jordaens (Luc)
textabstractObjectives: To compare the acute success and short-term follow-up of ablation of atrial flutter using 8 mm tip radiofrequency (RF) and cryocatheters. Methods: Sixty-two patients with atrial flutter were randomized to RF or cryocatheter (cryo) ablation. Right atrial angiography was perfor
Tung, Roderick; Shivkumar, Kalyanam; Mandapati, Ravi
Ablation of cavotricuspid ishtmus flutter and atrial tachycardia in a complex substrate has never been reported using remote navigation via superior approach. Venous access was obtained via right internal jugular for ablation and left subclavian for duodecapolar catheter placement into the coronary sinus. In a posttransplant patient presenting with both regular and irregular tachycardia, both cavotricuspid isthmus flutter in the donor and atrial tachycardia in the recipient was mapped using a...
de Almeida, Marcos Moura; Tavares, Wládia Gislaynne de Sousa; Furtado, Maria Mônica Alencar Araripe; Fontenele, Maria Marcia Farias Trajano
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. PMID:26525686
Pedersen, Ole Dyg; Bagger, Henning; Køber, Lars;
BACKGROUND: Reports on the prognostic importance of atrial fibrillation following myocardial infarction have provided considerable variation in results. Thus, this study examined the impact of left ventricular systolic function and congestive heart failure on the prognostic importance of atrial...... congestive heart failure were prospectively collected. Mortality was followed for 5 years. RESULTS: In patients with left ventricular ejection fraction<0.25, atrial fibrillation/atrial flutter was associated with an increased in-hospital mortality (OR=1.8 (1.1-3.2); p<0.05) but not an increased 30-day...... mortality. In patients with 0.250.35. In patients with congestive heart failure, atrial fibrillation/atrial flutter was associated with an increased in-hospital mortality (OR=1.5 (1.2-1.9); p<0.001) and increased 30-day mortality (OR=1.4 (1.1-1.7); p<0.001) but not in patients without congestive heart...
Bockeria O. L.
Full Text Available Myocardial noncompaction is associated with the development of heart failure and different arrhythmias. There are no typical arrhythmias for myocardial noncompaction. Various arrhythmias are clinically relevant because they may aggravate heart failure, may favor thromboembolism, like atrial fibrillation or flutter, or may lead to syncope or sudden cardiac death. In accumulated data we didn’t find description of left ventricular myocardial noncompaction, atrial flutter and intermittent Wolff–Parkinson–White (WPW syndrome. During electrophysiology study in patient with intermittent WPW syndrome programmed ventricular stimulation S1 = 500 ms, S2 = 260 ms was performed. Nonsustained ventricular tachycardia was induced. Then as a result of stimulation S1 = 500 ms, S2 = 240 ms fast ventricular tachycardia and ventricular fibrillation was induced. Then ventricular fibrillation was spontaneously terminated and converted into atrial fibrillation transmitted through the bypass tract with self-termination in 40 s. Cardiac contrast-enhanced magnetic resonanse imaging revealed left ventricular (LV myocardial noncompaction in apical and anterior segments of LV. There is no specific management of left ventricular myocardial noncompaction. In the present state of knowledge, an implantable cardioverterdefibrillator (ICD should be implanted in patients with myocardial noncompaction presenting with syncope and symptomatic ventricular arrhythmias in order to prevent sudden cardiac death. In this case patient refused from implanting an ICD.
Rudigwa, Priya; Elakkumanan, Lenin Babu; Rajan, Sakthi P; Prakash, M V Satya
ECG artefacts are defined as abnormalities in the monitored ECG, which result from measurement of cardiac potentials on the body surface and are not related to the electrical activity of the heart. In the operation theatre, the use of various types of electrical equipment may interfere with ECG interpretation. We describe our experience with artefacts resembling atrial fibrillation when a nerve integrity monitoring device was used on a patient undergoing posterior fossa surgery for epidermoid tumour. These artefacts resemble serious arrhythmias and may result in unwanted interventions. To enable better identification of such artefacts, a 12-lead ECG should be considered as it will display rhythm in all the leads; while artefacts will present in only a few leads, true arrhythmia will be present in all the 12 leads. Our case report aims to increase awareness regarding ECG artefacts and to explain how to distinguish them from actual arrhythmias. PMID:26021382
Takata, Junko; Haruyama, Naoko; Arashi, Tomoko; Mae, Tomoko
An 84-year-old male patient with a past history of atrial-flutter-fibrillation and dementia underwent an urgent femoral neck fracture surgery. Preoperative electrocardiography demonstrated atrial flutter (AFL) with ventricular conduction at a ratio of 2:1-4:1, and transthoracic echocardiography showed severe left ventricular dysfunction with Ejection Fraction of 14.6 %. Femoral nerve block and Lateral femoral cutaneous nerve block with sedation was planned for the surgery. Upon entry to the operating room, ECG showed 2:1 conducted AFL at the rate of 128 beats min(-1). Due to the stimulation of urethral catheter insertion, it has altered to 1:1 conducted AFL. Loading dose of landiolol hydrochloride 7.5 mg followed by 1.5-3 μg/kg/min continuous administration was given, which had decreased the conduction ratio to 2:1 without causing hypotension. A further episode of 1:1 conducted AFL occurred when the pin was inserted to the thighbone, which caused circulatory collapse. Additional bolus dose of landiolol immediately altered it to 2:1 before operating cardioversion and stabilized the hemodynamics. He maintained AFL with 2:1 conduction thereafter, and 1:1 conduction was never seen postoperatively even after discontinuation of landiolol. PMID:27085543
Goto, Eri; Nakamura, Kohki; Sasaki, Takehito; Naito, Shigeto
A 46-year-old man after a tricuspid valve replacement due to traumatic severe tricuspid regurgitation developed cavotricuspid isthmus-dependent counterclockwise atrial flutter. During a linear ablation using a contact force-sensing irrigated ablation catheter, the flutter could be terminated by a radiofrequency application within a deep pouch just below the bioprosthetic tricuspid valve.
Alberto Cresti; Francesco De Sensi; Gennaro Miracapillo; Ait-Ali Lamia; Pierluigi Festa.
Full Text Available A 51 male, affected by Tetralogy of Fallot, underwent a left Blalock-Taussig anastomosis at the age of two years and an aorto - right pulmonary artery tube graft when 8 years old. Complete surgical correction was performed at age 21 with closure of the ventricular septal defect and a large patch over the right outflow tract, shunts were discontinued. Then it was well up to 51 years old when he began to suffer shortness of breath with minimal exertion. A typical atrial flutter of the common type was diagnosed and a cavo-tricuspid isthmus ablation was successfully performed. Echocardiographic and magnetic resonance imaging and ergospirometry provided complete informations on anatomic and hemodynamic conditions but no other interventional procedure was necessary.
... heart (atria and the ventricles) work together to pump blood through the heart. A normal heartbeat begins as ... AFL makes it harder for the heart to pump blood effectively. With the blood moving more slowly, it ...
VANGELDER, IC; CRIJNS, HJ; VANGILST, WH; LIE, KI
The present study was undertaken to reassess prospectively the immediate and long-term results of direct-current electrical cardioversion in chronic atrial fibrillation or atrial flutter, and to determine factors predicting clinical outcome of the arrhthmia after direct-current cardioversion. Two-hu
Asmar, Abdo; Ross, Edward A
Despite transient hyperthyroidism reportedly occurring in ∼30% of post-parathyroidectomy (PTX) patients with primary hyperparathyroidism, it has rarely been described in the internal medicine literature. It occurs within days of surgery, is usually clinically mild or silent, and typically spontaneously resolves within weeks. Patients can, however, unusually present with symptoms and signs of thyrotoxicosis, including arrhythmias. We report a case of a hemodialysis patient who developed self-limited hyperthyroidism after intra-operative thyroid manipulation and excision during PTX surgery for secondary hyperparathyroidism that failed medical management. The patient was symptomatic with agitation, restlessness and new-onset atrial flutter, which required electrical cardioversion and temporary beta blockade. It is important that clinicians be aware of this potential surgical complication, so as to not attribute manifestations to post-PTX divalent cation disorders (i.e. hungry bone syndrome), thereby allowing prompt diagnosis and treatment. Post-operative monitoring of thyroid function is warranted for at least some subsets of patients: individuals who undergo thyroid exploration and palpation as part of their surgery to localize the parathyroid glands, as well as those with underlying cardiac disease or who are otherwise at high risk from even mild states of hyperthyroidism. PMID:25984129
Michaël Peyrol, MD
Full Text Available Right Atrial Flutter (AFL is a common form of macro reentrant arrhythmia.1–3 In absence of previous cardiac surgery, the reentry circuit is usually bounded anteriorly by the tricuspid annulus (TA and posteriorly by the ostia of vena cava and Eustachian ridge. In this case, AFL is consensually called "typical" AFL and is highly dependent of the cavotricuspid isthmus (CTI.2 The CTI is a critical channel which represents the predominant area of slow conduction of the circuit. Therefore, this narrow isthmus has become the universally accepted target for ablation of typical AFL.2–4If ablation is carried out during AFL the first "intuitive" procedure endpoint is arrhythmia termination. Although this latter was initially thought to be an acceptable endpoint for ablation procedure, bidirectional CTI conduction block is actually considered as the gold standard endpoint for elimination of typical AFL recurrence.5,6 Indeed, Schumacher et al. found a 9% recurrence rate after bidirectional CTI block achievement, 54% recurrence rate after unidirectional CTI block and 100% recurrence rate when persistent slow conduction across CTI was noted after RF application on the CTI.
WANG Fang; HUANG Cong-xin; CHEN Gang; ZHANG Feng; MENG Wei-dong; SUN Bao-gui
@@ Radiofrequency (RF) ablation of the critical isthmus between the tricuspid annulus and the inferior vena cava is commonly used to treat typical atrial flutter (AFL).1 This has become the first line therapy in Europe and in the US due to its high success rate and significant improvement in quality of life compared with conventional medical therapy.2 Sizeable lesions are required to achieve persistent bidirectional conduction block (BCB), which is the best endpoint to ensurelong-term success.3,4 Cooling the ablation electrode by irrigation has been shown to prevent both overheating of the electrode-tissue interface and impedance rise during RF delivery, allowing greater power delivery and larger,deeper lesion.5 Recent studies showed that pain-free cryoablation was comparable to RF ablation regardingthe short and long-term clinical success rate and safety.6However, no studies have shown that cryoablation is superior to the irrigation RF ablation. In this study, we compared the efficacy and safety of cryoablation with the irrigation radiofrequency ablation technologies for typical AFL.
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
Rafael Vieira Alcalde
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
Christine Benn Christiansen
Full Text Available Christine Benn Christiansen1, Christian Torp-Pedersen1, Lars Køber21Department of Cardiology, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; 2Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, DenmarkBackground: 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.Objective and methods: This is a review of 7 studies (DAFNE, ADONIS, EURIDIS, ATHENA, ANDROMEDA, ERATO and DIONYSOS on dronedarone focusing on efficacy, safety and prevention of stroke. There was a dose-finding study (DAFNE, 3 studies focusing on maintenance of sinus rhythm (ADONIS, EURIDIS and DIONYSOS, 1 study focusing on rate control (ERATO and 2 studies investigating mortality and morbidity (ANDROMEDA and ATHENA.Results: The target dose for dronedarone was established in the DAFNE study to be 400 mg twice daily. Both EURIDIS and ADONIS studies demonstrated that dronedarone was superior to placebo for maintaining sinus rhythm. However, DIONYSOS found that dronedarone is less efficient at maintaining sinus rhythm than amiodarone. ERATO concluded that dronedarone reduces ventricular rate in patients with chronic AF. The ANDROMEDA study in patients with severe heart failure was discontinued because of increased mortality in dronedarone group. Dronedarone reduced cardiovascular hospitalizations and mortality in patients with AF or AFL in the ATHENA trial. Secondly, according to a post hoc analysis a significant reduction in stroke was observed (annual rate 1.2% on dronedarone vs 1.8% on placebo, respectively [hazard ratio 0.66, confidence interval 0.46 to 0.96, P = 0.027]. In total, 54 cases of stroke occurred in 3439 patients (crude rate 1.6% receiving dronedarone compared to 76 strokes in 3048 patients on placebo (crude rate 2.5%, respectively.Conclusion: Dronedarone can be used for maintenance of
Da Costa, Antoine; Jamon, Yann; Romeyer-Bouchard, Cécile; Thévenin, Jérôme; Messier, Marc; Isaaz, Karl
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
Paraish Misra, MD
Full Text Available Guidelines strongly recommend long-term anticoagulation with warfarin for patients with newly recognized AF who have high embolic risk by virtue of a CHADS2 (Congestive Heart Failure, Hypertension, Age >65, Diabetes, History of Stroke score ≥ 2. The goal of this study was to determine patterns of emergency department-initiated anticoagulation among eligible patients discharged from Canadian centers with an episode of recent-onset atrial fibrillation and flutter (RAFF and determine if decision-making is driven by the CHADS2 score or other factors. This was accomplished by examining health records using uniform case identification and data abstraction as well as centralized quality control; it was conducted in 8 Canadian university emergency departments over a 12-month period. Eligible patients for this analysis demonstrated RAFF requiring emergency management, were not already taking warfarin and were not admitted to hospital. Univariate analyses were conducted using T-test or Chi-square to select factors associated with anticoagulation initiation at a significance level of p < 0.15 and multiple logistic regression was employed to evaluate independent predictors after adjustment for confounders. Among 633 eligible patients, only 21 out of 120 patients (18% with a CHADS2 score ≥ 2 received anticoagulation and among 70 patients who were given anticoagulation only 21 (30% had a CHADS2 score ≥ 2. Independent predictors of anticoagulation included age by 10-year strata: (OR = 1.7; 95% CI 1.3 – 2.1, heparin use in the anticoagulation (OR = 9.6; 95% CI 4.9 – 18.9, a new prescription for metoprolol (OR = 9.6; 95% CI 4.9 – 18.9 and being referred to cardiology for follow-up (OR = 5.6; 95% CI 2.6 – 12.0. CHADS2 ≥ 2 doubled the likelihood of being prescribed anticoagulation (OR= 2.0; 95% CI 1.5 – 3.5 but was not an independent predictor. It was thus determined that patients discharged from the emergency department in this study were not
Prashant Bhave MD
Full Text Available Atrial fibrillation affects approximately 3 million people in the United States and creates a huge burden on the health care system, both in terms of morbidity, mortality, and cost.1 The prevalence of atrial fibrillation rises sharply with increases in age. It is estimated that 8% of people above 70 years of age have atrial fibrillation.2-4 Atrial fibrillation has long been recognized as a powerful risk factor for stroke,5 heart failure,6 and mortality.7 Advancing age amplifies the risk of all of these sequelae of atrial fibrillation.
Prashant Bhave MD; Rod Passman MD, MSCE
Atrial fibrillation affects approximately 3 million people in the United States and creates a huge burden on the health care system, both in terms of morbidity, mortality, and cost.1 The prevalence of atrial fibrillation rises sharply with increases in age. It is estimated that 8% of people above 70 years of age have atrial fibrillation.2-4 Atrial fibrillation has long been recognized as a powerful risk factor for stroke,5 heart failure,6 and mortality.7 Advancing age amplifies the risk of al...
The posterior right atrial transverse conduction capability during typical atrial flutter (AFL) is well known, but its relationship to the anatomical characteristics remains controversial. Thirty-four AFL and 16 controls underwent intracardiac echocardiography after placement of a 20-polar catheter at the posterior block site during AFL or pacing. In 31 patients, the effective refractory period (ERP) at the block site was determined as the longest coupling interval that resulted in double potentials during extrastimuli from the mid-septal (SW) and free (FW) walls. The block site was located 3.0-29.0 mm posterior to the crista terminalis (CT) in each AFL and control patient. The CT area indexed to the body surface area was larger in AFL patients than in control patients (16.4±6.5 mm2/m2 vs 11.3±6.4 mm2/m2, p=0.01), and was positively correlated to age (r=0.34, p=0.02). The ERP was longer in the AFL patients than in controls (SW: median value 600 [270-725] ms vs 220 [200-253] ms; FW: 280 [230-675] ms vs 215 [188-260] ms, p<0.05 for each). A functional block line was located on the septal side of the CT in all patients. A limited conduction capability and age-related CT enlargement might have important implications for the pathogenesis in AFL. (author)
Objective:To explore the anticoagulant therapy method of cardiogenic stroke caused by atrial fibrillation or atrial flutter.Methods:We analyzed the anticoagulant therapy data of 200 patients with cardiogenic stroke caused by atrial fibrillation or atrial flutter.Results:52%of the patients received at least 1 time doses of warfarin.Compared with those who received aspirin,the bleeding conversion rate of warfarin treatment patients was low(P=0.03);16 patients were admitted to hospital within 3 months after discharge.Conclusion:Warfarin is an important drug for the prevention of atrial fibrillation or atrial flutter in patients with a high risk of stroke,and without increasing the incidence of adverse events.%目的：探讨心房颤动或心房扑动引发心源性卒中后抗凝血治疗方法。方法：分析200例心房颤动或心房扑动引发脑卒中患者的抗凝血治疗资料。结果：52%的患者接受至少1次剂量的华法林，接受华法林与接受阿司匹林者相比，接受华法林者出血转换率较低(P=0.03)；16例患者在出院3个月内再次因卒中住院。结论：华法林是心房颤动或心房扑动卒中高风险患者的重要预防药物，不增加不良事件发生率。
Jacob I. Haft; Louis E. Teichholz
Full Text Available The incidence of stroke in patients with atrial fibrillation or flutter (AF is well known and depends on the presence of risk factors. The incidence of AF in patients who have a stroke and its relationship to risk factors is not clear, however, because many stroke patients may have occult intermittent AF that is not present at the time of stroke and is not diagnosed. To better assess the incidence of AF, we studied the clinical records and all the 12 lead ECGs in a 14 year medical center data base of 985 patients admitted with ischemic stroke over a 3 year period and correlated the incidence of AF with the presence of the stroke risk factors. Of the stroke patients with congestive heart failure 61.9% had AF (95%CL 54.4, 68.9, with age >/= 75 years 45.2% had AF (CL 41.0,49.4, with coronary artery disease 42.9 had AF (CL 36.8, 49.2, with diabetes 39.2% had AF (CL 32.8,46.1 and with hypertension 33.7% had AF (CL 30.5, 37.1, all significantly higher than without these risk factors. Patients with more than one risk factor or with echo abnormalities, especially left atrial enlargement, had an even higher incidence of AF. These findings suggest that AF may be a very common mechanism whereby the stroke risk factors cause stroke. Stroke patients in normal sinus rhythm with these risk factors should be monitored for AF so they can receive anticoagulation to prevent a subsequent stroke if AF is diagnosed.
Pedersen, Ole Dyg; Abildstrøm, Steen Z; Ottesen, Michael M; Rask-Madsen, Christian; Bagger, Henning; Køber, Lars; Torp-Pedersen, Christian
AF facilitates induction of ventricular arrhythmias, which may increase the risk of sudden cardiovascular death (SCD). A close examination of the mode of death could potentially provide useful knowledge to guide further investigations and treatments. METHODS AND RESULTS: We analysed the relation......AIMS: Atrial fibrillation (AF) is a common complication in patients with acute myocardial infarction and is associated with an increase in the risk of death. The excess mortality associated with AF complicating acute myocardial infarction has not been studied in detail. Observations indicate that...... between AF/atrial flutter (AFL) and modes of death in 5983 consecutive patients discharged alive after an acute myocardial infarction screened in the TRAndolapril Cardiac Evaluation registry. This cohort of patients with an enzyme-verified acute myocardial infarction was admitted to 27 centres in 1990...
Achievement of complete conduction block in the cavotricuspid isthmus (CTI) is a curative ablation technique in patients with common atrial flutter (AFL). The present study was a prospective comparison of the efficacy of 2 ablation strategies in patients with common AFL: the continuous and point-by-point radiofrequency (RF) delivery techniques. Forty patients with common AFL were randomly assigned to either a group treated with a continuous RF delivery or to a group undergoing point-by-point RF ablation. In the first group, the RF energy was continuously delivered during a slow drag of the catheter tip from the tricuspid annulus to the inferior vena cava without stopping the application. In the second group, the RE ablation was performed using a point-by-point approach for 60 s at each point. All patients underwent ablation with an 8-mm-tip ablation catheter with a power limit of 50 W and a target temperature of 55 degC. Complete CTI conduction block was achieved in all patients. The patient characteristics, including the anatomy of the CTI estimated by 3-dimensional computed tomography, were no different between the 2 groups. The procedure time (time from the start of RF delivery to the completion of CTI block), fluoroscopic time and total RF energy required to create the CTI block between the continuous and point-by-point groups were 7.3±5.6 vs 21.2±22.2 min (p<0.01), 7.2±4.4 vs 16.2±14.1 min (p<0.05), and 15,631±6,001 vs 24,072±16,140 joules (p<0.05), respectively. There were no complications or recurrences of AFL during the follow-up period in any of the patients. In the curative treatment of common AFL, the continuous RF delivery approach could shorten the procedure and fluoroscopic time and reduce the total RF energy compared with the point-by-point RF ablation approach. (author)
Fibrilação atrial e flutter após operação de revascularização do miocárdio: fatores de risco e resultados Atrial fibrillation and flutter following coronary artery bypass graft surgery: risk factors and results
Marco Aurélio Vilela Borges LIMA
Full Text Available OBJETIVO: Determinar a incidência de fibrilação atrial e flutter (FAF no pós-operatório de revascularização do miocárdio (RM, bem como os fatores preditivos e a influência destas arritmias sobre o período de internação hospitalar. CASUÍSTICA E MÉTODOS: Foram analisados 275 pacientes submetidos à operação de revascularização do miocárdio isolada ou associada à correção de aneurisma de ventrículo esquerdo. A idade variou de 26 a 83 anos, com média de idade de 58,7 ± 9,5 anos. Cento e noventa e seis pacientes (71,3% eram do sexo masculino. RESULTADOS: A incidência total de fibrilação atrial e flutter pós-operatórios foi 16,4% com pico de incidência ocorrendo no segundo e terceiro dia de pós-operatório. Idade avançada, sexo masculino e história de fibrilação atrial ou flutter no pré-operatório foram identificados como fatores preditivos independentes de fibrilação atrial ou flutter no pós-operatório. Os pacientes que apresentaram FA ou flutter no pós-operatório em média 36 horas a mais na Unidade de Terapia Intensiva (UTI e 4,8 dias a mais hospitalizados. CONCLUSÃO: A FA e flutter são arritmias comuns no pós-operatório de revascularização do miocárdio, tendo efeito significativo sobre os tempos de permanência na UTI e de internação hospitalar.OBJECTIVE: The aim of this study was to determine the overall incidence and predictors of atrial fibrillation and flutter (AFF following CABG, as well as the influence of these arrhythmia on the hospital length of stay. MATERIAL AND METHODS: Two hundred and seventy-five patients, who had undergone coronary artery bypass graft (CABG surgery at the Beneficência Portuguesa Hospital in São Paulo, had their data collected and analyzed. The age range was from 26 to 83 years old with mean age of 58.7 and standard deviation of 9.5 years. One hundred and ninety six patients (71.3% were male. RESULTS: The outcomes of this analysis were: the overall incidence of
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
Hohnloser, S.H.; Connolly, S.J.; Crijns, H.J.G.M.;
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......ENts with Atrial fibrillation/atrial flutter) is the largest single antiarrhythmic drug trial ever conducted. More than 4,600 patients with a history of AF or atrial flutter (AFL) have been randomized to receive dronedarone 400 mg bid or matching placebo. The primary study endpoint is time to first....... 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...
Revishvili А. Sh.
Conclusion. This type of tachycardia following after an atrial fibrillation surgery may be considered as a failing transmural myocardial damage during the procedure. The catheter method can be used succesfully unless there are no effects of antiarrhythmic therapy. The catheter method enables not only to verify the disconnection between the left atrial pulmonary veins and left atrium myocardium but also to perform the ablation in zones of the atrial myocardium that are anatomic substrates of post surgery tachyarrhythmias.
Ablação do flutter atrial típico: estudo prospectivo e randomizado do cateter irrigado fechado versus cateter com eletrodo distal de 8 mm Ablation of typical atrial flutter: a prospective randomized study of cooled-tip versus 8-mm-tip catheters
Sissy L. Melo
Full Text Available OBJETIVOS: Trabalho prospectivo, randomizado para comparar a eficácia e a segurança do cateter irrigado em relação ao cateter com eletrodo distal de 8 mm para ablação com radiofreqüência (RF do flutter atrial. MÉTODOS: Em 52 pacientes consecutivos referidos para tratamento do flutter atrial típico, a ablação do istmo cavotricuspídeo (Ist-CT foi realizada com cateter de irrigação fechada (n=26 ou com cateter de eletrodo distal de 8 mm (n=26. Os pulsos de RF foram aplicados ponto a ponto por 60 segundos com potência limitada a 50 w com o cateter irrigado e por controle de temperatura (60ºC, 70 w com cateter de 8 mm. O critério de fim do procedimento foi a obtenção de bloqueio bidirecional do Ist-CT. RESULTADOS: O bloqueio Ist-CT foi obtido em 98,1% dos pacientes. O "crossover" ocorreu em quatro pacientes do grupo com cateter irrigado. Não se encontrou diferença estatística significante em relação aos parâmetros da ablação, tais como tempo total de aplicação de RF (591,1±309,0s vs 486,2±250,8s, duração do procedimento (86,4 ± 23,6 vs 78,1±22,5min e tempo de fluoroscopia (17,0±6,7 vs 15,4±4,6min entre os dois grupos. Durante seguimento médio de 10,6 meses, um paciente do grupo irrigado apresentou recorrência do flutter atrial típico. CONCLUSÃO: A ablação do Ist-CT resultou ser efetiva e segura para o controle do flutter atrial com ambas as técnicas empregadas (cateter com eletrodo distal de 8 mm e cateter irrigado. A complexidade técnica do cateter irrigado proporciona menor competitividade.OBJECTIVES: Both ablation catheters with closed irrigated system and 8mm tip-catheters have been shown to be more effective for typical atrial flutter radiofrequency (RF ablation when compared to conventional 4 mm tip catheter. Considering the differences in complexity and costs of both systems, a prospective study was designed to compare the efficacy and safety of cooled-tip and 8mm-tip catheters for atrial flutter
Kohári, Mária; Pap, Róbert
Atrial tachycardias are common after open heart surgery. Most commonly these are macro-reentrant including cavotricuspid isthmus dependent atrial flutter, incisional right atrial flutter and left atrial flutter. Focal atrial tachycardias occur less frequently. The specific type of atrial tachycardia highly depends on the type of surgical incision. Catheter ablation can be very effective, however requires a thorough understanding of anatomy and surgical technique.
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
Connolly, Stuart J; Crijns, Harry J G M; Torp-Pedersen, Christian;
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......BACKGROUND: 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....../atrial flutter). METHODS AND RESULTS: 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...
吕薇; 牛铁生; 曹乾
AIM To investigate the influence of pre-injected magnesium sulfate on the conversion effect of ibutilide on atrial fibrillation or flutter. METHODS Sixty -four patients who has atrial fibrillation or flutter were randomized to give placebo plus ibutilide group (control group) or magnesium sulfate plus ibutilide group (trial group) , receive either an infusion of 100 mL of 0.9% sodium chloride or the same amount of sodium chloride with 20 mL of 25% magnesium sulfate in one hour. After 10 min, ibutilide was infused. The conversion rate of atrial fibrillation or flutter and adverse events were observed. RESULTS Conversion rate of ibutilide for atrial fibrillation or flutter in the control group and the trial group is 50% and 84% respectively (P < 0.05). Adverse events are not significantly different between the two groups. CONCLUSION Pre - injection of mag -nesium sulfate enhances the ability of ibutilide for the conversion of atrial fibrillation or flutter.%目的 观察预先静脉给予硫酸镁对伊布利特转复心房颤动/心房扑动的影响.方法 选择符合条件的心房颤动/心房扑动患者64例,随机单盲法分为安慰剂+伊布利特组(对照组)和硫酸镁+伊布利特组(试验组),分别在1h内静脉滴注氯化钠注射液100 mL或氯化钠注射液100 mL加25％硫酸镁20 mL,10 min后给予伊布利特静脉注射,观察两组患者的心房颤动/心房扑动转复率及不良事件发生情况.结果 对照组与试验组对于心房颤动/心房扑动的转复率分别为50％及84％,两组比较差异显著(P＜0.05)；两组间不良反应发生率无显著差异(P＞0.05).结论 预先静脉给予硫酸镁可显著提高伊布利特转复心房颤动/心房扑动的成功率.
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
José Marcos Moreira
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
Faniel, R; Schoenfeld, P
Twenty-six consecutive patients (14 males, 12 females--mean age 66.6) were admitted to an intensive care unit (ICU) because of a rapid ventricular response to atrial fibrillation (RAF). Fourteen of them had been unsuccessfully treated by drugs (other than amiodarone) and/or DC shock before admission. A loading dose of i.v. amiodarone was administered (repeated boluses of 3 mg/kg in 3 min, or 30 min-infusions of 5 to 7.5 mg/kg), followed by continuous infusion, in order to reach a maximal total dosage of 1500 mg in 24 h. This treatment was considered efficacious if a reversion to stable sinus rhythm (SSR) occurred within 24 h and was maintained for more than 48 h. This was achieved in 21 out of 26 patients (80.8%). The mean time between the administration of therapy and the occurrence of SSR was 171 min. The total dose of amiodarone delivered to effect SSR was 6.9 +/- 2.3 mg/kg. No adverse reactions were encountered during the bolus injection but we recommend that continuous infusion be carried out through a central venous catheter to avoid phlebitis. The administration of 7 mg/kg of intravenous amiodarone delivered in 30 min proved a safe and successful first choice of management in atrial fibrillation with a rapid ventricular response. PMID:6861767
Feld, Gregory K
Recent studies have demonstrated a high degree of efficacy of 8 mm electrode-tipped or saline-irrigated-tip catheters for ablation of atrial flutter (AFL). These catheters have a theoretical advantage as they produce a large ablation lesion. However, large-tip ablation catheters have a larger surface area and require a higher power radiofrequency (RF) generator with up to 100 W capacity to produce adequate ablation temperatures (50-60 degrees C). The potential advantages of a large-tip ablation catheter and high-power RF generator include the need for fewer energy applications, shorter procedure and fluoroscopy times, and greater efficacy. Therefore, the safety and efficacy of AFL ablation using 8 or 10 mm electrode catheters and a 100-W RF generator was studied using the Boston Scientific, Inc., EPT-1000 XP cardiac ablation system. There were 169 patients, aged 61 +/- 12 years involved. Acute end points were bidirectional isthmus block and no inducible AFL. Following ablation, patients were seen at 1, 3 and 6 months, with event monitoring performed weekly and for any symptoms. Three quality of life surveys were completed during follow-up. Acute success was achieved in 158 patients (93%), with 12 +/- 11 RF energy applications. The efficacy of 8 and 10 mm electrodes did not differ significantly. The number of RF energy applications (10 +/- 8 vs. 14 +/- 8) and ablation time (0.5 +/- 0.4 vs. 0.8 +/- 0.6 h) were less with 10 mm compared with 8 mm electrodes (p free of symptoms at 12 and 24 months, respectively. Ablation of AFL improved quality of life scores (p generator was safe, effective and improved quality of life. The number and duration of RF applications was lower with 10 mm compared with 8 mm electrode catheters. PMID:16293039
目的 观察新一代Ⅲ类抗心律失常药物伊布利特和经典Ⅲ类抗心律失常药物胺碘酮转复心房颤动(房颤)和心房扑动(房扑)的成功率及安全性.方法 选择40 ～ 75岁,持续时间≤90 d的房颤和房扑患者38例,按入院顺序随机分为伊布利特组19例和胺碘酮组19例,伊布利特组体质量≥60 kg者首剂1 mg、体质量＜60 kg者首剂0.01 mg/kg,如无效10 min后再给予1 mg或0.01 mg/kg；胺碘酮组首剂150 mg,如无效10 min后再给予150 mg,观察转复率和转复时间,记录不良反应.结果 伊布利特和胺碘酮组4h内转复窦律分别为78.9％和31.5％,24 h内转复窦律分别为84.2％和52.6％,平均转复时间分别为(19±12)min和(48 ±17)min (P＜0.01).两组均未发生致命性不良反应.结论 伊布利特与胺碘酮均能终止房颤和房扑,伊布利特转复房颤、房扑的疗效高于胺碘酮,转复时间短于胺碘酮,但须在严格监控下进行.%Objective To investigate the efficacy,safety and tolerance of intravenous ibutilide and amiodarone for conversion of atrial fibrillation( AF) and flutter( AFL) to normal sinus rhythm.Methods Thirty - eight consecutive patients aged 40 - 75 years with AF/AFL were included.The duration of arrhythmia were less than 90 days (ranged from 3 hours to 90 days),and ventricular rate(VR) were more than 60 beats/min.Two groups were assigned randomly.Patients in the ibutilide group( 19 cases) received ibutilide 1 mg if body weight ≥60 kg or 0.01 mg/kg if body weight ＜ 60 kg; Treatment was repeated if atrial fibrillation or flutter was not converted after 10 min of the first dosage.Patients in the amiodarone group( 19 cases) received amiodarone 150 mg,followed by amiodarone 150 mg if atrial fibrillation or flutter persisted after 10 min of the first dosage.Results In 4 hours AF/AFL were converted in 15 of 19 patients(78.9％ )in ibutilide group and in 6 of 19 patients(31.5％ )in amiodarone group (P ＜ 0.05),and in 24
Nair, Krishna Kumar Mohanan; Namboodiri, Narayanan; Thajudeen, Anees; Valaparambil, Ajitkumar; Jaganmohan A Tharakan
Lower loop re-entry (LLR) flutter is a rare type of atypical right atrial flutter. Most of the reported cases occurred in association with typical flutter patterns as a transient arrhythmia. Our case is unique in the fact the LLR was sustained and persisted independently.
Full Text Available OBJETIVO: Estudar a importância clínica da determinação eletrofisiológica da presença de bloqueio bidirecional na condução pelo istmo localizado entre a veia cava inferior e o anel da valva tricúspide (VCI - AT, após a ablação do flutter atrial tipo I (FL com radiofreqüência (RF. MÉTODOS: Quarenta pacientes consecutivos (idade média 51±11 anos com FL foram submetidos a ablação do istmo VCI-AT com RF. Em 30 pacientes (GI, o sucesso foi avaliado pela interrupção e não reindução do FL com estimulação atrial programada. Nos últimos 10 pacientes foi avaliada também a condução bidirecional pelo istmo, com cateteres posicionados na sua entrada e saída e em cada lado da linha de bloqueio. O bloqueio foi considerado bidirecional quando ocorrido nos dois sentidos e unidirecional quando ocorrido em um só sentido. RESULTADOS: Vinte e seis (86% pacientes do GI e 10 (100% do GII tiveram sucesso imediato (p= 0,5558. Durante o seguimento, 7 (30% de 23 pacientes do GI e 3 (30% de 9 do GII tiveram recorrência de FL (p= NS. Os três pacientes do GII que apresentaram recorrência tinham bloqueio unidirecional, enquanto os seis casos sem recorrência tinham bloqueio bidirecional (p=0,012. CONCLUSÃO: A demonstração de bloqueio bidirecional no istmo VCI-AT, obtida imediatamente após a ablação do FL com RF, relaciona-se a menor índice de recorrência clínica, devendo ser o critério preferencial para término do procedimento.
环磷腺苷葡胺联合地尔硫治疗慢性肺心病心衰合并快速房扑房颤的临床观察%Clinical Observation of Adenosine Cyclophosphate Combined with Diltiazem in the Treatment of Chronic Pul-monary Heart Disease Heart Failure Complicated with Rapid Atrial Fibrillation and Atrial Flutter
目的：观察环磷腺苷葡胺联合地尔硫治疗慢性肺心病心衰合并快速房扑房颤的临床疗效及安全性。方法：选择慢性肺心病心衰合并快速房扑房颤患者100例，按随机数字表法分为观察组和对照组，各50例。对照组患者给予常规治疗，观察组在常规治疗的基础上口服地尔硫，30 mg/次，1次/d，同时加用环磷腺苷葡胺180 mg加入5％葡萄糖注射液200 ml中静脉滴注，1次/d，疗程均为10 d。观察两组患者给药前后的心率、肺动脉压、左室射血分数以及临床疗效。结果：治疗后观察组和对照组分别有43、31例患者临床症状明显改善、心率达标，两组比较差异有统计学意义（P＜0.05）；观察组患者肺动脉压下降幅度、左室射血分数较对照组均有明显好转，差异有统计学意义（P＜0.05）。两组患者均未出现心动过缓、低血压、哮喘及心衰加重等副作用。结论：环磷腺苷葡胺联合地尔硫治疗慢性肺心病心衰合并快速房扑房颤，能显著改善患者心功能、控制心率、加快病情的好转，且安全性好。%OBJECTIVE:To observe clinical efficacy and safety of adenosine cyclophosphate combined with diltiazem in the treatment of chronic pulmonary heart disease heart failure complicated with atrial fibrillation and atrial flutter. METHODS:100 cas-es of chronic pulmonary heart disease heart failure complicated with rapid atrial fibrillation and atrial flutter were randomly divided into observation group and control group,with 50 cases in each group. The control group was given conventional treatment,and the observation group was additionally given diltiazem orally,30 mg/time,once a day,and adenosine cyclophosphate 180 mg add-ed into 5% Glucose injection 200 ml intravenously,once a day,for 10 days,on the basis of conventional treatment. The heart rate,the pressure of pulmonary artery and left ventricular ejection fraction(LVEF)before and
Verhoosel, C.V.; Gutiérrez, M. A.; Hulshoff, S.J.
The field of fluid-structure interaction is combined with the field of stochastics to perform a stochastic flutter analysis. Various methods to directly incorporate the effects of uncertainties in the flutter analysis are investigated. The panel problem with a supersonic fluid flowing over it is considered as a testcase. The stochastic moments (mean, standard deviation, etc.) of the flutter point are computed by an uncertainty analysis. Sensitivity-based methods are used to determine the stoc...
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.
Rustam G. Habchabov
Full Text Available Reasons of development of life-threatening arrhythmias that lead to sudden and total death in cases of cardiovascular diseases are still unclear, though cardiac research of this problem is conducted throughout the world. Damage of connective tissues insulation cover of the heart’s conductive pathways with oxidation of ectopic nodes can lead to life-threatening arrhythmias. This damage has never been considered before as a cause of electrical instability of the heart. Accordingly, treatment of such patients should change, and consequently should reduce the total number of sudden deaths due to cardiovascular diseases.The speed of electricity conduction from the heart to the nervous system and its distribution throughout the body remains underestimated. Slowdown of electric magnetic induction (acceleration between the heart and the central nervous system as well as slowdown of its distribution results in insufficient speed of electric flow and reduction of bioelectric processes of the body. This leads to activation of the sympathetic nervous system with the subsequent cascade of pressor mechanisms and development of essential hypertension.
Intra-atrial course of the right coronary artery is a rare anomaly. The recognition of this entity is crucial to avoid potential hazards related to vessel injury during interventional procedures such as right heart catheterization, pacemaker implantation, invasive electrophysiology testing or atrial flutter ablation. We present a case of a 62-year old female with paroxysmal atrial flutter and atrial fibrillation, whose cardiac computed tomography revealed an anomalous course of the right coronary artery through the right atrium. Cardiac computed tomography examination enables an accurate assessment of morphology and location of the anomalous vessel course
Ruhlin, C. L.; Doggett, R. V., Jr.; Gregory, R. A.
The paper describes an experimental and analytical study of the transonic flutter characteristics of an empennage flutter model having an all-movable horizontal tail with a geared elevator. Two configurations were flutter tested: one with a geared elevator and one with a locked elevator with the model cantilever-mounted on a sting in the wind tunnel. The geared-elevator configuration fluttered experimentally at about 20% higher dynamic pressures than the locked-elevator configuration. The experimental flutter boundary was nearly flat at transonic speeds for both configurations. It was found that an analysis which treated the elevator as a discrete surface predicted flutter dynamic pressure levels better than analyses which treated the stabilizer and elevator as a warped surface. Warped-surface methods, however, predicted more closely the experimental flutter frequencies and Mach number trends.
Jin, Qi; Pehrson, Steen; Jacobsen, Peter Karl;
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......, and a cavotricuspid isthmus dependent atrial flutter and a focal atrial tachycardia in the donor atria. 3D electroanatomical mapping and ablation were guided by remote magnetic navigation (RMN). Atrial fibrillation continued in the recipient atria even after the donor heart was converted to sinus...... rhythm by ablation. CONCLUSIONS: It is critical to understand the surgical anatomy of a bi-atrial anastomosis and its relevant electrical activation pattern before ablation. Appropriate electroanatomical mapping strategy with RMN can facilitate the successful ablation of post-transplant atrial...
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.
Wu, Zhigang; Cooper, Jonathan
Active flutter suppression is used to prevent flutter throughout the flight envelope by supplying active control forces in response to vehicle motions. In recent years, studies have been conducted on active flutter suppression using the receptance method. The advantage of the receptance method is that the feedback control gains are purely based upon measured receptances, without any need to evaluate or know the mass, damping, and stiffness matrices of the system. However, determination of the...
Liberos Mascarell, Alejandro
[EN] Atrial tachyarrhythmias present a high prevalence in the developed world, and several studies predict that in the coming decades it will be increased. Micro or macro-reentrant mechanisms of the electrical wavefronts that govern the mechanical behavior of the heart are one of the main responsibles for the maintenance of these arrhythmias. Atrial flutter is maintained by a macro-reentry around an anatomical or functional obstacle located in the atria. In the case of atrial fibrillation, th...
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...... precision by using stability diagrams. Furthermore, the physical transparency of the aerodynamic damping and stiffness terms is increased because the development in vertical and torsional damping and stiffness is analysed instead of flutter derivatives....
York, Darrell L.
The design of modern high-performance aircraft is toward increased aerodynamic efficiency, decreased structural weight, and higher flight speeds. Preliminary designs often exhibit a flutter instability within the desired operating envelope of the aircraft. Passive methods which have been used to solve the flutter problem include added structural stiffness, mass balancing, and speed restrictions. These methods may result in significant weight penalties. Studies by Boeing (ref. 1) show that wei...
Argentina, M; Argentina, Mederic
We give an explanation for the onset of wind-induced flutter in a flag. Our theory accounts for the various physical mechanisms at work: the finite length and the small but finite bending stiffness of the flag, the unsteadiness of the flow, the added mass effect and vortex shedding from the trailing edge. Our analysis allows us to predict a critical speed for the onset of flapping as well as the frequency of flapping. We find that in a particular limit corresponding to a low density fluid flowing over a soft high density flag, the flapping instability is akin to a resonance between the mode of oscillation of a rigid pivoted airfoil in a flow and a hinged-free elastic filament vibrating in its lowest mode.
This paper presents a review of current work in transonic blade flutter research. Aerodynamic analyses for the prediction of attached flow flutter, choke flutter, and stall flutter are described. Also reviewed are unsteady aerodynamic measurement and flutter test programs that have recently been completed or are in progress to investigate transonic blade flutter phenomena.
A piezoelectric actuator has the benefits of flexibility of its position, without time lag and wide bandpass characteristics. The early results of the wind tunnel flutter suppression test using the piezoeletric actuator were presented in Ref.［1］. A rigid rectangular wing model is constrained by a plunge spring and a pitch spring, and a pair of piezoelectric actuators is bonded on both sides of the plunge spring so as to carry out the active control. Refs.［2,3］ reported two flutter suppression wind tunnel tests where the distributed piezoelectric actuators were used. In Ref.［2］ low speed wind tunnel tests were conducted with aluminum and composite plate-like rectangular models fully covered by piezoelectric actuators. Flutter speed is increased by 11%. In Ref.［3］ a composite plate-like swept back model with piezoceramic actuators bonded on the inboard surface was tested in a transonic wind tunnel and a 12% increment of flutter dynamic pressure was achieved. In the present investigation, an aluminum plate-like rectangular model with inboard bonded piezoceramic actuators is adopted. Active flutter suppression control law has been designed. A series of analyses and ground tests and, finally, low-speed wind tunnel tests with the active control system opened and closed are conducted. Reasonable results have been obtained.
Objective To investigate the association between CHADS2score and long-term(≥3 years)outcomes post catheter ablation in patients with atrial fibrillation(AF).Methods AF patients who received single catheter ablation in our hospital from January 2004 to March 2009 in our department were included and patients received regular follow-up.AF recurrence was defined as the occurrence of atrial arrhythmias(AF,atrial flutter and atrial tachycardia)recorded by electrocardiogram monitor(≥30 seconds)after ablation during follow-up period(after
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 (ff) 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 ff 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 f1, f2, and other peak frequencies as linear combinations thereof (mf1±nf2), 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
Vlček, Václav; Kozánek, Jan; Zolotarev, Igor
Brno: Brno University of Technology, 2014 - (Fuis, V.), s. 688-691 ISBN 978-80-214-4871-1. ISSN 1805-8248. [Engineering Mechanics 2014 /20./. Svratka (CZ), 12.05.2014-15.05.2014] R&D Projects: GA ČR GA13-10527S Institutional support: RVO:61388998 Keywords : aeroelasticity * flutter * interferometry * subsonic flow Subject RIV: BI - Acoustics
目的 对比普遍与灌注冷却射频消融电极在Ⅰ型心房扑动（CAFL）消融中的作用。方法 60例CAFL患者随机分为两组：普通射频消融电极治疗组（CRF）和灌注冷却射频消融电极治疗组（IRF），分别比较两组取得下腔静脉与三尖瓣环峡部双向阻滞的手术时间、X线照射时间、射频消融放电次数及放电时间、并观察消融时电能、阻抗以及温度的改变。结果 IRF组的手术时间、X线照射时间、射频消融时间均较CRF组短（P<0.01），放电次数也少（P<0.05），IRF组消融过程中阻抗变化小、电能稳定，温度差异不明显，而CRF组则相反，且有19例出现碳化现象，两组痛感差异无显著性，均无心包填塞、栓塞等并发症。结论 灌注冷却射频消融电极在CAFL消融中优越于普通射频消融电极。%Objective To compare the effects of common ablation catheter and irrigated ablation catheter on common atrial flutter (CAFL). Methods 60 patients with CAFL were randomly dividied into common catheter group (CRF, 30cases) and irrigated catheter group (IRF, 30 cases). The procedure duration, fluoroscopy duration and radio frequeney duration were studied. The RF energy, impedance and temparature during the ablation were observed. Results The duration of procedure, fluoroscopy time and radio frequency ablation time were significantly shorter in IRF group than those in CRF group (P<0.01), there was also a difference in the times of ablation between two groups (P<0.05). In IRF group, the variation of impedance, RF-energy and temperature during the ablation was small, but in CRF group, the variation was obvious and there were 19 cases with coagulum formation. The degree of the chest pain was similar between two groups, there were no serious complications such as pericardial effusion, thrombi etc. Conclusion Irrigated ablation catheter should be superior to common ablation catheter in CAFL ablation.
Camm, A. John; Toft, Egon; Torp-Pedersen, Christian;
, 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...
Eduardo B. Saad, MD, PhD, FHRS; Charles Slater, MD, FHRS, RCES, CCDS, CEPS Meet the expert doctor Doctor Do You want to talk to a Electro physiologist about your AFIB..?? Then ask now! Now It's Free* Dr. Y Madhu Reddy, MD, FACC, FHRS Introduction to AFib Click here for more Videos..! Upcoming Events
Full Text Available Introduction: The left atrial posterior wall has been shown to play na important role in AF pathophysiology. Objective: Evaluate the efficacy of an ablation strategy designed to completely isolate the LA posterior wall, on top of PV isolation. Methods and Results: 25 pts (72% male age 65 ± 12 years undergoing AF ablation for persistent or long term persistent AF. Mean AF duration was 11 ± 3 months and mean LA diameter was 4.8 ± 0.4 mm. After complete PVI, a “Roof Line” was created between the top of each contralateral set of lesions and a “floor line” closed the posterior wall in a “Box” fashion, connecting the bottom of each set of contralateral lesions. After an average follow-up of 16 ± 2 months, 20 patients (80% were free of any atrial arrhythmia recurrences (18 of whom off drugs. Five patients (20% had sustained atypical flutter and required a new ablation procedure. All these patients had mitral isthmus dependent flutters and no electrical conduction in the PVs or posterior wall were detected. Conclusions: Complete LA posterior wall isolation on top of PV is associated with good outcomes in patients with persistent and long-standing persistent AF when performed using meticulous bidirectional isolation criteria and adenosine infusion. Recurrences occur predominately as perimitral flutter, without gaps in the posterior wall.
In this thesis single-degree-of-freedom torsional airfoil flutter is investigated using an incompressible potential flow code, a compressible inviscid Euler code and a compressible viscous Navier-Stokes code. It is found that the classical linearized incompressible and compressible flow theories yield unconservative flutter estimates. The computations based on the non-linear codes show for NACA 0006, NACA 0009, NACA 0012 and NACA 0015 airfoils, that the regions of torsional flutter instabilit...
The wind turbine blades often subjected by a phenomenon fluttering which leads to a structural damage. Therefore, it is necessary for design engineers to predict the fluttering behavior while designing the blades. The main scope of the thesis is to analyze and study the fluttering behavior by conducting structural analysis, modal analysis, Aeroelastic stability analysis and FSI of standard wind turbine blade. The analysis is carried out in ANSYS work bench and the preliminary results shows th...
Hiren N Doshi
Full Text Available Atrial pacing in the neonate is rarely done due to constraints of equipment, technical knowhow, and risk of complications. We describe a novel method of atrial pacing in the new born using equipment readily available in any intensive care unit. Atrial pacing can be achieved using an adult bipolar pacing wire directly introduced through the umbilical venous route. We have used this method in 5 neonates, and achieved atrial capture in 4 patients. Temporary atrial pacing is a therapeutic option in a few neonatal arrhythmias, such as atrial flutter, a few types of re-entrant tachycardias, such as accessory pathway mediated tachycardia and junctional reciprocating tachycardia, and has a limited role in cardiopulmonary resuscitation where sinoatrial node dysfunction is suspected.
With the increasing need for alternative sources of energy, a great deal of attention is drawn to harvesting energy from ambient vibration. These vibrations may be caused by fluid forces acting upon a structure. When a flexible structure is subject to a fluid flow, it loses stability at a certain flow velocity and starts to vibrate. This self-induced motion is called flutter where energy is continuously transferred from the fluid to the structure. In this study a piezoelectric film sensor is ...
Torp-Pedersen, Christian; Crijns, Harry J G M; Gaudin, Christophe;
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).......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...
Kowey, P R; Marinchak, R A; Rials, S J; Filart, R A
Atrial fibrillation (AFib) is a common clinical entity, responsible for significant morbidity and mortality, but it also accounts for a large percentage of healthcare dollar expenditures. Efforts to treat this arrhythmia in the past have focused on subacute antithrombotic therapy and eventually use of antiarrhythmic drugs for maintenance of sinus rhythm. However, there has been a growing interest in the concept of acute electrical and pharmacologic conversion. This treatment strategy has a number of benefits, including immediate alleviation of patient symptoms, avoidance of antithrombotic therapy, and prevention of electrophysiologic remodeling, which is thought to contribute to the perpetuation of the arrhythmia. There is also increasing evidence that this is a cost-effective strategy in that it may obviate admission to the hospital and the cost of long-term therapy. This article represents a summary of the treatments that may be used acutely to control the ventricular response to AFib, prevent thromboembolic events, and provide for acute conversion either pharmacologically or electrically. It includes information on modalities that are currently available and those that are under active development. We anticipate that an active, acute treatment approach to AFib and atrial flutter will become the therapeutic norm in the next few years, especially as the benefits of these interventions are demonstrated in clinical trials. PMID:9525568
Lip, Gregory Y H; Fauchier, Laurent; Freedman, Saul B; Van Gelder, Isabelle; Natale, Andrea; Gianni, Carola; Nattel, Stanley; Potpara, Tatjana; Rienstra, Michiel; Tse, Hung-Fat; Lane, Deirdre A
Atrial fibrillation (AF) is the most common sustained cardiac rhythm disorder, and increases in prevalence with increasing age and the number of cardiovascular comorbidities. AF is characterized by a rapid and irregular heartbeat that can be asymptomatic or lead to symptoms such as palpitations, dys
Olesen, Morten S; Nielsen, Morten W; Haunsø, Stig;
Atrial fibrillation (AF) is the most common cardiac arrhythmia affecting 1-2% of the general population. A number of studies have demonstrated that AF, and in particular lone AF, has a substantial genetic component. Monogenic mutations in lone and familial AF, although rare, have been recognized...
... Find People About NINDS NINDS Atrial Fibrillation and Stroke Information Page Table of Contents (click to jump ... done? Clinical Trials What is Atrial Fibrillation and Stroke? Atrial fibrillation (AF) describes the rapid, irregular beating ...
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Does conversion and prevention of atrial fibrillation enhance survival in patients with left ventricular dysfunction? Evidence from the Danish Investigations of Arrhythmia and Mortality ON Dofetilide/(DIAMOND) study
Pedersen, Ole Dyg; Brendorp, Bente; Elming, Hanne;
BACKGROUND: Atrial fibrillation is a common arrhythmia in patients with left ventricular dysfunction associated with increased morbidity and mortality. The present study investigated the potential of dofetilide to restore and maintain sinus rhythm in patients with left ventricular dysfunction......, which might reduce mortality and hospitalizations. METHODS AND RESULTS: In the Danish Investigations of Arrhythmia and Mortality ON Dofetilide (DIAMOND) studies, 506 patients were in atrial fibrillation (AF) or atrial flutter (AFl) at baseline. Over the course of study, cardioversion occurred in 148 (59...
Brennen, C.; Oey, K. T.; Babcock, C. D.
This paper presents the results of experiments and analysis of the phenomenon of leading-edge flutter which has been observed to occur for supercavitating hydrofoils. The experiments confirmed the existence of such a single-degree-of-freedom flutter involving chordwise bending and indicated that for long, natural (or vapor-filled) cavities the reduced flutter speed, [formula], was in the range 0.15 to 0.23. Secondary effects observed were the variation with the angle of attack (a minimum fl...
Kaiser, Stefanie; Kirst, Malte; Kunze, Christophe
Two versions of a new detector for automatic real-time detection of atrial fibrillation in non-invasive ECG signals are introduced. The methods are based on beat to beat variability, tachogram analysis and simple signal filtering. The implementation on mobile devices is made possible due to the low demand on computing power of the employed analysis procedures. The proposed algorithms correctly identified 436 of 440 five minute episodes of atrial fibrillation or flutter and also correctly identified up to 302 of 342 episodes of no atrial fibrillation, including normal sinus rhythm as well as other cardiac arrhythmias. These numbers correspond to a sensitivity of 99.1 % and a specificity of 88.3%.
Nielsen, Jens Erik Rokkedal; Wachtell, K; Abdulla, J
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-...
Barr, Yael R.; Watkins, Sharmila D.; Polk, J. D.
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
Weimar, Timo; Gaynor, Sydney L; Seubert, Daniela Y; Damiano, Ralph J; Doll, Nicolas
The need to perform an additional atriotomy is a major concern that keeps many surgeons from performing an extended left atrial lesion set in patients with atrial fibrillation during procedures such as aortic valve replacement. This does result either in a suboptimal lesion set or even in ignoring the rhythm disorder, leaving the patient exposed to an increased risk of stroke and possible hemodynamic compromises. This report describes a technique how pulmonary vein isolation, an isolation of the posterior left atrial wall and an anterior mitral annular line, which substitutes for the mitral isthmus line in order to prevent perimitral atrial flutter, can be performed during aortic valve replacement without the need for an atriotomy. This technique allows for an optimal time management by minimizing additional cardiopulmonary bypass-time and cross-clamp-time; however, its equivalent efficacy in successfully treating atrial fibrillation compared to the left atrial Maze IV ablation pattern needs to be revealed in future trials. PMID:26777943
Christiansen, Lasse Engbo; Lehn-Schiøler, Tue; Mosekilde, Erik;
The paper describes the effects of random external excitations on the onset and dynamical characteristics of transonic flutter (i.e. large-amplitude, self-sustained oscillations) for a high aspect ratio wing. Wind tunnel experiments performed at the National Aerospace Laboratory (NAL) in Japan have...... reproduce several of the experimentally observed modifications of the flutter transition. In particular, the models display the characteristic phenomena of coherence resonance....
Ashawesh, Gamal Mohamed
This research work presents series of investigations into the structural dynamics and dynamic aeroelastic (flutter) behaviour of composite and metal wings. The study begins with a literature review where the development and an over view of the previous investigations in this field are presented. Static stiffness is very important to any type of analysis, especially in both dynamic and flutter analysis as in this case. Therefore, different methods are presented and used for the ...
DRAPKINA O.M.; A. V. Emelyanov
Mechanisms of atrial fibrosis including the role of serotonin in the development of this lesion in patients with atrial fibrillation are presented. New approaches to the treatment of atrial fibrillation aimed at atrial fibrosis reduction are discussed.
Full Text Available In this paper we use an efficient arrhythmia algorithm based on wavelet transform. In first step, QRS complexes are detected. Then each QRS is delineated by detecting and identifying the peaks of the individual waves, complex onset and end. Then the determination of P and T wave peaks, onset and ends are performed. Finally the Ventricular flutter, ventricular tachycardia, supra ventricular tachycardia, ventricular fibrillation, atrial fibrillation and atrial flutter that are kinds of acute ventricular-atrial arrhythmias are detected. In the proposed algorithm, we used a second order spline as mother wavelet and improved the previous algorithms proposed by other investigators. We evaluated the algorithm on some manually annotated single ECG signals selected from MIT-BIH arrhythmia databases. This algorithm may achieve the mean detection accuracy of about 80% in these arrhythmias.
Flutter is a self-feeding and potentially destructive vibration that can lead to devastating effects such as broken blades. Using accurate numerical models to predict flutter in the conception of an engine is essential to avoid huge waste of money. The software 2, using the elsA CFD package developed by the French Aerospace Lab, ONERA, is used to perform unsteady calculations and predict flutter margin. The current methodology does not systematically manage to reproduce the expected flutter p...
Wind-induced flutter of bridges occurs as coupled torsional and vertical oscillation, or uncoupled torsional oscillation. Bridges with bluff, non-streamlined sections are prone to torsional flutter. Prediction of torsional flutter on the basis of measured aerodynamic derivatives essentially corresponds to the prediction of coupled flutter, although, compared to the latter, it can be largely simplified. The theoretical background is discussed and the given formulae are checked against empirica...
Lip, Gregory Y H; Fauchier, Laurent; Freedman, Saul B; Van Gelder, Isabelle; Natale, Andrea; Gianni, Carola; Nattel, Stanley; Potpara, Tatjana; Rienstra, Michiel; Tse, Hung-Fat; Lane, Deirdre A
Atrial fibrillation (AF) is the most common sustained cardiac rhythm disorder, and increases in prevalence with increasing age and the number of cardiovascular comorbidities. AF is characterized by a rapid and irregular heartbeat that can be asymptomatic or lead to symptoms such as palpitations, dyspnoea and dizziness. The condition can also be associated with serious complications, including an increased risk of stroke. Important recent developments in the clinical epidemiology and management of AF have informed our approach to this arrhythmia. This Primer provides a comprehensive overview of AF, including its epidemiology, mechanisms and pathophysiology, diagnosis, screening, prevention and management. Management strategies, including stroke prevention, rate control and rhythm control, are considered. We also address quality of life issues and provide an outlook on future developments and ongoing clinical trials in managing this common arrhythmia. PMID:27159789
El-Damaty, Ahmed; Love, Michael; Parkash, Ratika
Left atrial ablation has become more commonplace with the advent of catheter ablation for atrial fibrillation. A number of transseptal sheaths have been produced to enhance safe and efficient catheter manipulation in the left atrium (LA) for these procedures. Some of the sheaths have been subject to recall due to partial or complete detachment of its radiopaque tip. We report a case of a 46 year-old female diagnosed with idiopathic dilated cardiomyopathy that presented with atypical left atrial flutter. During electrophysiologic study, a Swartz braided SL1 (SL-1) transseptal sheath was used to introduce the ablation catheter to the left atrium. During left atrial mapping, the radiopaque tip of the sheath detached from the rest of the sheath and was seen floating in the LA. After exchanging the SL-1 sheath with a deflectable sheath, the detached segment was retrieved out of the LA and eventually out of the vascular system using an angioplasty balloon advanced over a wire and inflated distal to the lumen of the detached tip. The root cause of this malfunction was found to be lack of a secondary bonding process that these sheaths generally undergo during the manufacturing process. We describe the case of a left atrial ablation procedure where a novel percutaneous method was able to successfully retrieve the detached tip of a transseptal sheath from the vascular system, thereby avoiding a potential catastrophic complication or thoracotomy. This method may be useful in other cases where similar circumstances may present. PMID:22162088
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
The effects of small periodic disturbances on the response of a two-degree-of-freedom, non-conservative, mechanical system are analyzed. The system is a simple model for panel flutter. The disturbance simulates the pressure fluctuations of a turbulent boundary layer on the panel. Asymptotic expansions of the solutions are obtained for small amplitude disturbances. The qualitative features of the response depend on the prescribed variation of the disrurbance frequency with the magnitude of the non-conservative applied force. The disturbance can induce a smooth transition to the fluttering states of the rods; or it may induce jump transitions. The results suggest a possible technique for delaying panel flutter, by applying periodic forcing functions with appropriate frequencies. (Author)
Full Text Available Flutter analysis is considered for the minimum altitude at which the minimum designed Mach number is achieved, for the maximum altitude at which the maximum designed dynamic pressure is obtained and for the minimum altitude at which transonic effects begin occurring. Moreover, analyzes is performed for any other altitudes considered necessary. Flutter analysis results is graphically presented in equivalent speed with the curves of structural damping coefficient g required for flutter according to the flutter speed. Flutter analysis aims to determine the speeds of IAR 99 SOIM.
Andersen, Michael Styrk; Sahin, Emrah; Laustsen, Benjamin;
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 with a...... torsional-to-vertical frequency ratio = 0.89 is presented. Using a multimodal flutter approach and bridge deck flutter derivatives equal to those of a thin airfoil, classical flutter was shown not to occur....
The Flutter suppression using distributed piezoelectric actuators has been analyzed and tested. In constructing the finite element equation, effects of piezoelectric matrices are investigated. LQG method is used in designing the control law. In reducing the order of the control law, both balance realization and LK methods are used. For the rational approximation of the unsteady aerodynamic forces LS method is improved. In determining the piezoelectric constants d31 a new dynamic response method is developed. Laser vibrameter is used to pick up the model response and in ground resonance test the model is excited by piezoelectric actuators. Reasonable agreement of the wind tunnel flutter suppression test with calculated results is obtained.
Jérôme, Mougel; Sébastien, Michelin; Olivier, Doaré
A flag in axial flow is subject to flutter instability that leads to large-amplitude flapping of the structure. When two flags are placed parallel to each other, they interact hydrodynamically leading to coupled dynamics of the system. The understanding of the possible dynamical regimes is crucial in the recent context of energy harvesting using piezoelectric fags. In this study, we consider coupled-flutter of two slender flags. Based on an extension of the famous model by Lighthill commonly called Large Amplitude Elongated Body Theory to the two-flags case, both linear and large-amplitude dynamics of such a coupled system will be presented.
... this page: //medlineplus.gov/ency/patientinstructions/000237.htm Atrial fibrillation - discharge To use the sharing features on this ... have been in the hospital because you have atrial fibrillation . This condition occurs when your heart beats faster ...
Lip, Gregory Y. H.; Watson, Timothy
Acute atrial fibrillation is rapid, irregular, and chaotic atrial activity of less than 48 hours' duration. It resolves spontaneously within 24 to 48 hours in over 50% of people. In this review we have included studies on patients with onset up to 7 days previously. Risk factors for acute atrial fibrillation include increasing age, CVD, alcohol abuse, diabetes, and lung disease.Acute atrial fibrillation increases the risk of stroke and heart failure.
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 circu...
... Pressure High Blood Pressure Tools & Resources Stroke More Atrial Fibrillation in Children Updated:Jul 18,2016 Does your ... content was last reviewed on 04/16/14. Atrial Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters • ...
Atrial Fibrillation Atrial fibrillation, often called AFib or AF, is the most common type of heart arrhythmia. An arrhythmia is when the ... Atrium Sinoatrial Node (pacemaker) Atrioventricular Node Left Atrium Atrial Fibrillation AFib Facts 1 • An estimated 2.7–6. ...
Plasma toroidal rotation can limit reconnection of externally applied resonant magnetic perturbation (RMP) fields δB on rational magnetic flux surfaces. Hence it causes the induced radial perturbations δBρ to be small there, thereby inhibiting magnetic island formation and stochasticity at the top of pedestals in high (H-mode) confinement tokamak plasmas. However, the δBρs induced by RMPs increase away from rational surfaces and are shown to induce significant sinusoidal radial motion (flutter) of magnetic field lines with a radial extent that varies linearly with δBρ and inversely with distance from the rational surface because of the magnetic shear. This produces a radial electron thermal diffusivity that is (1/2)(δBρ/B0)2 times a kinetically derived, electron-collision-induced, magnetic-shear-reduced, effective parallel electron thermal diffusivity in the absence of magnetic stochasticity. These low collisionality flutter-induced transport processes and thin magnetic island effects are shown to be highly peaked in the vicinity of rational surfaces at the top of low collisionality pedestals. However, the smaller but finite level of magnetic-flutter-induced electron heat transport midway between rational surfaces is the primary factor that determines the electron temperature difference between rational surfaces at the pedestal top. The magnetic-flutter-induced non-ambipolar electron density transport can be large enough to push the plasma toward an electron density transport root. Requiring ambipolar density transport is shown to determine the radial electric field, the plasma toroidal rotation (via radial force balance), a reduced electron thermal diffusivity and increased ambipolar density transport in the pedestal. At high collisionality the various flutter effects are less strongly peaked at rational surfaces and generally less significant. They are thus less likely to exhibit flutter-induced resonant behaviour and transition toward an electron
Babuty, D; D'Hautefeuille, B; Scheck, F; Mycinsky, C; Pruvost, P; Peraudeau, P
In a randomized, double-blind, parallel clinical trial, the authors tested and compared flecainide and cibenzoline, a new antiarrhythmic drug, on atrial arrhythmias. Sixty-eight patients (36 men, 32 women, mean age 62.5 +/- 1.6 years) with documented symptomatic paroxysmal atrial arrhythmias (fibrillation in 56, flutter in 12) were recruited and received either cibenzoline 260 mg/day (n = 33) or flecainide 200 mg/day (n = 35). Patients were assessed with physical examination, resting ECG, 24-hour ambulatory ECG recording, two-dimensional echocardiography, and standard biologic titrations before the inclusion day, and 3 months and 6 months after the randomization day. Sixteen patients were withdrawn (7 were lost to follow-up, 7 had side effects, 2 had another medical event). Seventeen patients had documented recurrence of atrial arrhythmia (9 in the cibenzoline group, 8 in the flecainide group) during the study. The efficacy of cibenzoline and flecainide for preventing recurrence of atrial arrhythmias was not significantly different (62.5% versus 71.4%). Eleven patients complained of one or more side effects (cibenzoline, n = 6; flecainide, n = 5), justifying leaving the trial in 6 cases (cibenzoline, n = 3; flecainide, n = 3). Two ventricular proarrhythmic effects were observed. No atrial proarrhythmic effects were reported. The efficacy of cibenzoline and flecainide for preventing atrial arrhythmia is good and similar during a follow-up period of 6 months. In view of these results, cibenzoline may be administered first to prevent atrial arrhythmia. PMID:7657846
Kusay H. Jabir
Full Text Available The aerodynamic and elastic forces may cause an oscillation of the structure such as the high frequency of the airfoil surfaces and the dynamic instability occurring in an aircraft in flight and failure may occur at a speed called flutter speed. In this work, analytical and numerical investigations of flutter limits of thin plates have been carried out. The flutter speed of rectangular plates were obtained and compared with some published results. Different design parameters were investigated such as aspect ratio, thickness and their effects on flutter velocity. It was found that the structural mode shape plays an important role in the determination of the flutter speed and the coupling between the bending and torsional mode is the main cause of flutter.
Park, Kyoung-Min; Hwang, Jin Kyung; Chun, Kwang Jin; Park, Seung-Jung; On, Young Keun; Kim, June Soo; Park, Seung Woo; Kang, I-Seok; Song, Jinyoung; Huh, June
Atrial tachyarrhythmia is a well-known long-term complication of atrial septal defect (ASD) in adults, even after successful trans-catheter closure. However, the risk factors for early-onset atrial tachyarrhythmia after trans-catheter closure remain unclear. This retrospective study enrolled adults with secundum ASD undergoing trans-catheter closure from January 2000 to March 2014. We analyzed the clinical characteristics of patients and assessed risk factors for new-onset atrial tachyarrhythmia defined as a composite of atrial fibrillation or flutter (AF/AFL) after ASD closure. We enrolled a total of 427 patients; 123 were male (28.8%) and the median age was 37.0 (interquartile range [IQR]: 18.3-49.0). Nineteen (4.4%) patients had documented atrial tachyarrhythmia during the follow-up period (median: 11.4 months [IQR: 5.4-24]). Patients with transient AF/AFL during closure showed a greater incidence of new-onset atrial tachyarrhythmia during the follow-up period than patients with consistent sinus rhythm during closure (27.3% vs 3.8%; P = 0.01). Most new-onset atrial tachyarrhythmias were documented within 6 months (median: 2.6 [IQR: 1.2-4.1] months) of closure. In the multivariate analysis, the risk for new-onset atrial tachyarrhythmia was significant in patients with AF/AFL during closure (hazard ratio [HR]: 9.90, 95% confidence interval [CI]: 2.86-34.20; P < 0.001), deficient posteroinferior rim (HR: 5.48, 95% CI: 1.15-25.72; P = 0.04), and age of closure over 48 years (HR: 3.30, 95% CI: 1.30-8.38; P = 0.01). In conclusion, transient AF/AFL during trans-catheter closure of ASD as well as deficient posteroinferior rim and age of closure over 48 years may be useful for predicting early new-onset atrial tachyarrhythmia after device closure. PMID:27583905
Dorin LOZICI-BRINZEI; Simion TATARU; Daniela BARAN
Flutter analysis is considered for the minimum altitude at which the minimum designed Mach number is achieved, for the maximum altitude at which the maximum designed dynamic pressure is obtained and for the minimum altitude at which transonic effects begin occurring. Moreover, analyzes is performed for any other altitudes considered necessary. Flutter analysis results is graphically presented in equivalent speed with the curves of structural damping coefficient g required for flutter accordin...
Kusay H. Jabir
The aerodynamic and elastic forces may cause an oscillation of the structure such as the high frequency of the airfoil surfaces and the dynamic instability occurring in an aircraft in flight and failure may occur at a speed called flutter speed. In this work, analytical and numerical investigations of flutter limits of thin plates have been carried out. The flutter speed of rectangular plates were obtained and compared with some published results. Different design parameters were investigated...
Nur Azam; Erwin Sulaeman
ABSTRACT: Flutter may be considered to be one of the most dangerous aeroelastic failure phenomenon. The flutter characteristic differs for each aircraft type, and depends on the wing geometry as well as its operational region of subsonic, transonic or supersonic speeds. Prior to performing a flight flutter test, extensive numerical simulations and Ground Vibration Test should be conducted where the structural finite element modes and the experimentation results should be matched, otherwise th...
... page from the NHLBI on Twitter. How Is Atrial Fibrillation Treated? Treatment for atrial fibrillation (AF) depends on ... too much thyroid hormone). Who Needs Treatment for Atrial Fibrillation? People who have AF but don't have ...
... Atrial Fibrillation » How Is Atrial Fibrillation Diagnosed? Explore Atrial Fibrillation What Is... Types Other Names Causes Who Is at Risk Signs & Symptoms Diagnosis Treatments Prevention Living With Clinical Trials Links Related Topics Arrhythmia ...
Kim, Ki Woong; Kwon, Hyuk Chan; Kim, Ki Dam; Lee, Yong Ho; Kim, Jin Mok; Kim, In Seon; Lim, Hyun Kyoon; Park, Yong Ki [Biomagnetism Research, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Kim, Doo Sang [Seoul Veterans Hospital, Seoul (Korea, Republic of); Lim, Seung Pyung [Chungnam National University Hospital, Daejeon (Korea, Republic of)
We propose a method to measure atrial arrhythmias (AA) such as atrial fibrillation (Afb) and atrial flutter (Afl) with a SQUID magnetocardiograph (MCG) system. To detect AA is one of challenging topics in MCG. As the AA generally have irregular rhythm and atrio-ventricular conduction, the MCG signal cannot be improved by QRS averaging; therefore a SQUID MCG system having a high SNR is required to measure informative atrial excitation with a single scan. In the case of Afb, diminished f waves are much smaller than normal P waves because the sources are usually located on the posterior wall of the heart. In this study, we utilize an MCG system measuring tangential field components, which is known to be more sensitive to a deeper current source. The average noise spectral density of the whole system in a magnetic shielded room was 10 fT/Hz(a) 1 Hz and 5 fT/Hz(a) 100 Hz. We measured the MCG signals of patients with chronic Afb and Afl. Before the AA measurement, the comparison between the measurements in supine and prone positions for P waves has been conducted and the experiment gave a result that the supine position is more suitable to measure the atrial excitation. Therefore, the AA was measured in subject's supine position. Clinical potential of AA measurement in MCG is to find an aspect of a reentry circuit and to localize the abnormal stimulation noninvasively. To give useful information about the abnormal excitation, we have developed a method, separative synthetic aperture magnetometry (sSAM). The basic idea of sSAM is to visualize current source distribution corresponding to the atrial excitation, which are separated from the ventricular excitation and the Gaussian sensor noises. By using sSAM, we localized the source of an Afl successfully.
Terranova, Paolo; Severgnini, Barbara; Valli, Paolo; Dell'Orto, Simonetta; Greco, Enrico Maria
Pacing prevention algorithms have been introduced in order to maximize the benefits of atrial pacing in atrial fibrillation prevention. It has been demonstrated that algorithms actually keep overdrive atrial pacing, reduce atrial premature contractions, and prevent short-long atrial cycle phenomenon, with good patient tolerance. However, clinical studies showed inconsistent benefits on clinical endpoints such as atrial fibrillation burden. Factors which may be responsible for neutral results ...
Christiansen, Lasse Engbo; Lehn-Schiøler, Tue; Mosekilde, Erik;
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....
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.
Vestergaard, Peter; Schwartz, Kristoffer; Pinholt, Else Marie; Rejnmark, Lars; Mosekilde, Leif
flutter was present for any drug except for etidronate (OR = 1.22, 95% CI 1.15-1.29). After initiation of treatment, raloxifene was not associated with any excess risk of atrial fibrillation (OR = 0.98, 95% CI 0.72-1.33). Etidronate (HR = 1.08, 95% CI 1.02-1.14) and alendronate (HR = 1.09, 95% CI 1...
D. A. Francis; Heron, J. R.
A patient with suspected multiple sclerosis is described who presented with attacks of blurring of vision and ocular flutter. This has not previously been reported as an isolated paroxysmal manifestation of brain stem demyelination. As with other paroxysmal disturbances ocular flutter may present as the first sign of the disease.
The flutter of viscoelastic of orthotropic plates streamlined by a gas current are investigated. The basic direction of the present work consists in taking into account of viscoelastic material properties at supersonic speeds. An algorithm of the numerical solution for the problem has been worked out on the basic of the method. The results of the flutter critical speed calculations have been given.
A quasilinear theory of particle and energy flux by magnetic flutter associated with drift waves is presented. It is shown that magnetic flutter can enhance the energy flux. However, particle diffusion is ambipolar and runaway electrons do not escape along the field lines. (author)
B. A. Khudayarov
The flutter of viscoelastic plates and cylindrical panels streamlined by a gas current are investigated. The basic direction of the present work consists in taking into account of viscoelastic material properties at supersonic speeds. An algorithm of the numerical solution for the problem has been worked out on the basic of the method. The results of the flutter critical speed calculations have been given.
Kim, Taeseong; Shin, SanJoon; Kim, Taehyoun
The whirl flutter phenomenon in a rotor is induced by in-plane hub forces, and imposes a serious limit on the forward speed. In this paper, based on Greenberg’s model, quasi-steady and unsteady aerodynamic forces are formulated to examine the whirl flutter stability for a three-bladed rotor witho...
Full Text Available With expected success rates in excess of 80% for achieving long term arrhythmia control, catheter based ablation has become a popular treatment strategy in the management of patients with atrial fibrillation (AF. However, the success of AF ablation has been tempered by the occurrence of post procedure left atrial tachycardias and / or flutters, which can be seen in up to 30% of the patients. These arrhythmias are perpetuated either due to abnormalities of impulse formation (abnormal automaticity / triggered activity, or abnormalities of impulse conduction (micro / macroreentry. Regardless of the underlying mechanism, these tachycardias manifest distinct “P” or flutter waves on the surface ECG, recognition of which may facilitate their characterization / localization. However, because of the frequent overlap in the morphology of P waves, intracardiac mapping is often the only way to distinguish them apart. This is accomplished using a combination of activation, entrainment and electroanatomic mapping techniques. Tachycardias resulting from abnormalities of impulse formation and / or microreentry are characteristically focal and usually confined in and around pulmonary vein (PV segments which have reconnected (septal aspect of right PVs and anterior aspect of left PVs. In contrast, macroreentrant tachycardias manifest a large circuit dimension involving zone(s of slow conduction. These are most commonly seen to occur around the mitral valve but can develop in any part of the left atrium where “gaps” across prior ablation lesion sets create altered conduction. Successful ablation of focal tachycardias is usually accomplished by isolating the reconnected PV segment(s. In case of macroreentrant arrhythmias however, a more extensive ablation approach is typically required in order to achieve conduction block across isthmus of the circuit. Using these strategies, the majority of left atrial tachycardias occurring post AF ablation can be
Nieberding, W. C.; Pollack, J. L.
The paper examines the capabilities of photoelectric scanning (PES) and stroboscopic imagery (SI) as optical monitoring tools for detection of the onset of flutter in the fan blades of an aircraft gas turbine engine. Both optical techniques give visual data in real time as well as video-tape records. PES is shown to be an ideal flutter monitor, since a single cathode ray tube displays the behavior of all the blades in a stage simultaneously. Operation of the SI system continuously while searching for a flutter condition imposes severe demands on the flash tube and affects its reliability, thus limiting its use as a flutter monitor. A better method of operation is to search for flutter with the PES and limit the use of SI to those times when the PES indicates interesting blade activity.
The flutter instability and response of finite-span flexible plates in uniform flow are investigated experimentally. The effects of the plate aspect ratio on its dynamic responses are mainly analyzed. A hysteretic phenomenon is observed and can be described such that the plate flutters spontaneously as the flow velocity is greater than a critical value U*C and the plate returns to its stable state as the flow velocity is slowly decreased to another critical one U*D. We find that the aspect ratio has a greater effect on U*C than on U*D. The flutter frequency decreases and the amplitude increases with the increase in the flow velocity. When the flutter instability of the plate occurs, three typical flutter modes are identified and are associated with the aspect ratio and the flow velocity. (fundamental areas of phenomenology (including applications))
Llinares Llopis, Raúl; Igual García, Jorge
[EN] Atrial fibrillation disorders are one of the main arrhythmias of the elderly. The atrial and ventricular activities are decoupled during an atrial fibrillation episode, and very rapid and irregular waves replace the usual atrial P-wave in a normal sinus rhythm electrocardiogram (ECG). The estimation of these wavelets is a must for clinical analysis. We propose a new approach to this problem focused on the quasiperiodicity of these wavelets. Atrial activity is characterized by...
Gilyard, G. B.; Edwards, J. W.
Flight flutter-test results of the first aeroelastic research wing (ARW-1) of NASA's drones for aerodynamic and structural testing program are presented. The flight-test operation and the implementation of the active flutter-suppression system are described as well as the software techniques used to obtain real-time damping estimates and the actual flutter testing procedure. Real-time analysis of fast-frequency aileron excitation sweeps provided reliable damping estimates. The open-loop flutter boundary was well defined at two altitudes; a maximum Mach number of 0.91 was obtained. Both open-loop and closed-loop data were of exceptionally high quality. Although the flutter-suppression system provided augmented damping at speeds below the flutter boundary, an error in the implementation of the system resulted in the system being less stable than predicted. The vehicle encountered system-on flutter shortly after crossing the open-loop flutter boundary on the third flight and was lost. The aircraft was rebuilt. Changes made in real-time test techniques are included.
Andersen, A.; Pesavento, U.; Wang, Z. Jane
We investigate the aerodynamics of freely falling plates in a quasi-two-dimensional flow at Reynolds number of 10(3) , which is typical for a leaf or business card falling in air. We quantify the trajectories experimentally using high-speed digital video at sufficient resolution to determine the instantaneous plate accelerations and thus to deduce the instantaneous fluid forces. We compare the measurements with direct numerical solutions of the two-dimensional Navier Stokes equation. Using inviscid theory as a guide, we decompose the fluid forces into contributions due to acceleration, translation, and rotation of the plate. For both fluttering and tumbling we find that the fluid circulation is dominated by a rotational term proportional to the angular velocity of the plate, as opposed to the translational velocity for a glider with fixed angle of attack. We find that the torque on a freely falling plate is small, i.e. the torque is one to two orders of magnitude smaller than the torque on a glider with fixed angle of attack. Based on these results we revise the existing ODE models of freely falling plates. We get access to different kinds of dynamics by exploring the phase diagram spanned by the Reynolds number, the dimensionless moment of inertia, and the thickness-to-width ratio. In agreement with previous experiments, we find fluttering, tumbling, and apparently chaotic motion. We further investigate the dependence on initial conditions and find brief transients followed by periodic fluttering described by simple harmonics and tumbling with a pronounced period-two structure. Near the cusp-like turning points, the plates elevate, a feature which would be absent if the lift depended on the translational velocity alone.
Lind, Rick; Brenner, Marty; Freudinger, Lawrence C.
Wavelets present a method for signal processing that may be useful for analyzing responses of dynamical systems. This paper describes several wavelet-based tools that have been developed to improve the efficiency of flight flutter testing. One of the tools uses correlation filtering to identify properties of several modes throughout a flight test for envelope expansion. Another tool uses features in time-frequency representations of responses to characterize nonlinearities in the system dynamics. A third tool uses modulus and phase information from a wavelet transform to estimate modal parameters that can be used to update a linear model and reduce conservatism in robust stability margins.
Full text: Plasma toroidal rotation can prevent or limit reconnection of externally applied resonant magnetic perturbation (RMP) fields δB on rational magnetic flux surfaces. Hence, it causes the induced radial perturbations to vanish or be small there, and thereby inhibits magnetic island formation and stochasticity in the edge of high (H-mode) confinement tokamak plasmas. However, the radial component of the spatial magnetic flutter induced by RMP fields off rational surfaces causes a radial electron thermal diffusivity of (1/2)(δBp/B)2 times a magnetic-shear-influenced effective parallel electron thermal diffusivity. The resultant RMP-flutter-induced electron thermal diffusivity can be comparable to experimentally inferred values at the top of H-mode pedestals. This process also causes a factor of about 3 smaller RMP-induced electron density diffusivity there. Because this electron density transport is non-ambipolar, it produces a toroidal torque on the plasma, which is usually in the co-current direction. Kinetic-based cylindrical screw-pinch and toroidal models of these RMP-flutter-induced plasma transport effects have been developed. The RMP-induced increases in these diffusive plasma transport processes are typically spatially inhomogeneous in that they are strongly peaked near the rational surfaces in low collisionality pedestals, which may lead to resonant sensitivities to the local safety factor q. The effects can be large enough to reduce the radially averaged gradients of the electron temperature and density at the top of H-mode edge pedestals, and modify the plasma toroidal rotation and radial electric field there. At high collisionality the various effects are less strongly peaked at rational surfaces and thus less likely to exhibit RMP-induced resonant behavior. These RMP-flutter-induced plasma transport processes provide a new paradigm for developing an understanding of how RMPs modify the pedestal structure to stabilize peeling-ballooning modes
Methods for predicting the onset of flutter during an experiment are traditionally applied treating the data as deterministic values. Uncertainty and variation in the data is often glossed over by using best-fit curves to represent the information. This paper applies stochastic treatments to wind tunnel data obtained for the Piezoelectric Aeroelastic Response Tailoring Investigation model. These methods include modal amplitude tracking, modal frequency tracking and several applications of the flutter margin method. The flutter margin method was developed by Zimmerman and Weissenburger, and extended by Poirel, Dunn and Porter to incorporate uncertainty. Much of the current work follows the future work recommendations of Poirel, Dunn and Porter.
Full Text Available ABSTRACT: Flutter may be considered to be one of the most dangerous aeroelastic failure phenomenon. The flutter characteristic differs for each aircraft type, and depends on the wing geometry as well as its operational region of subsonic, transonic or supersonic speeds. Prior to performing a flight flutter test, extensive numerical simulations and Ground Vibration Test should be conducted where the structural finite element modes and the experimentation results should be matched, otherwise the numerical simulation model must be rejected. In this paper, the analysis of simulation of a supersonic wing equipped with external missiles loaded on the wing is presented. The structural mode shapes at each generated frequency are also visually presented. The analysis is carried out using MSC Nastran FEM software. The wing flutter with the external stores was simulated at different altitudes. The result shows that the flutter velocity is sensitive to the flight altitude. For this reason, the flutter analysis is conducted also for a negative altitude. The negative altitude is obtained by considering the constant equivalent speed-Mach number rule at the flutter speed boundary as a requirement in standard regulation of transport aircraft. ABSTRAK: Salah satu fenomena kegagalan aeroelastik yang paling membahayakan adalah kipasan (flutter. Ciri-ciri kegagalan kipasan (flutter adalah berbeza untuk setiap jenis pesawat bergantung pada geometri sayap dan regim operasi sama ada subsonik, transonik atau supersonik. Sebelum melakukan ujian penerbangan kipasan , simulasi berangka luas dan ujian getaran peringkat bawahan (darat perlu dijalankan di mana struktur mod unsur terhingga dan keputusan eksperimen harus dipadankan, sebaliknya model simulasi berangka boleh ditolak. Dalam kertas kerja ini, simulasi sayap supersonik dilengkapi dengan beban luaran peluru berpandu di sayap telah dianalisis di daerah supersonik tinggi. Bentuk mod struktur pada setiap mod frekuensi
Bierbooms, W.; Rodenburg, R. (Instituut voor Windenergie, Vakgroep Mechanica en Constructies, Faculteit der Civiele Techniek, Technische Univ. Delft (Netherlands))
One of the problems in the research on the dynamic stability of wind turbines is the stability of a rotor with side vane. Such wind mills are developed by the Eindhoven University of Technology in the Netherlands for the use of water pumps in developing countries. The function of the side vane is to keep the rotor wind-oriented. During stormy weather on the test field in Almere, Netherlands, in January 1990 flutter phenomenons were observed for the vane of the CWD 2000 mill. A simple model has been developed to describe the flutter phenomenon by means of two degrees of freedom (torsion and pitch). The impact of some relevant parameters can be investigated by this model. 7 figs., 3 refs.
Steinberg, Benjamin A; Piccini, Jonathan P.
Atrial fibrillation increases the risk of stroke, which is a leading cause of death and disability worldwide. The use of oral anticoagulation in patients with atrial fibrillation at moderate or high risk of stroke, estimated by established criteria, improves outcomes. However, to ensure that the benefits exceed the risks of bleeding, appropriate patient selection is essential. Vitamin K antagonism has been the mainstay of treatment; however, newer drugs with novel mechanisms are also availabl...
Casado Corpas, José; López Díez, Jesús
The present article shows a procedure to predict the flutter speed based on real-time tuning of a quasi non-linear aeroelastic model. A two-dimensional non-linear (freeplay) aeroeslastic model is implemented inMatLab/Simulink with incompressible aerodynamic conditions. A comparison with real compressible conditions is provided. Once the numerical validation is accomplished, a parametric aeroelastic model is built in order to describe the proposed procedure and contribute to reduce the number ...
Evrard, P.; Sakalihasan, Natzi; R. Garcia; Van Laere, Anne-Sophie; Patterson, B.
After conversion of atrial fibrillation, it is important to maintain sinus rhythm. In addition antiarrhythmic drugs, biatrial resynchronization seems to prevent recurrences of atrial fibrillation in patients with interatrial conduction block: local experience.
Sessa, Maurizio; Mascolo, Annamaria; Andersen, Mikkel Porsborg;
PURPOSE: This study investigated the impact of chronic kidney disease on all-causes and cardiovascular mortality in patients with atrial fibrillation treated with digoxin. METHODS: All patients with non-valvular atrial fibrillation and/or atrial flutter as hospitalization diagnosis from January 1......, 1997 to December 31, 2012 were identified in Danish nationwide administrative registries. Cox proportional hazard model was used to compare the adjusted risk of all-causes and cardiovascular mortality among patients with and without chronic kidney disease and among patients with different chronic...... kidney disease stages within 180 days and 2 years from the first digoxin prescription. RESULTS: We identified 37,981 patients receiving digoxin; 1884 patients had the diagnosis of chronic kidney disease. Cox regression analysis showed no statistically significant differences in all-causes (Hazard Ratio...
Piccolroaz, Andrea; Willis, John R
Flutter instability in an infinite medium is a form of material instability corresponding to the occurrence of complex conjugate squares of the acceleration wave velocities. Although its occurrence is known to be possible in elastoplastic materials with nonassociative flow law and to correspond to some dynamically growing disturbance, its mechanical meaning has to date still eluded a precise interpretation. This is provided here by constructing the infinite-body, time-harmonic Green's function for the loading branch of an elastoplastic material in flutter conditions. Used as a perturbation, it reveals that flutter corresponds to a spatially blowing-up disturbance, exhibiting well-defined directional properties, determined by the wave directions for which the eigenvalues become complex conjugate. Flutter is shown to be connected to the formation of localized deformations, a dynamical phenomenon sharing geometrical similarities with the well-known mechanism of shear banding occurring under quasi-static loading....
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...
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...
Cunningham, Herbert J.; Batina, John T.; Bennett, Robert M.
The application and assessment of the recently developed CAP-TSD transonic small-disturbance code for flutter prediction is described. The CAP-TSD code has been developed for aeroelastic analysis of complete aircraft configurations and was previously applied to the calculation of steady and unsteady pressures with favorable results. Generalized aerodynamic forces and flutter characteristics are calculated and compared with linear theory results and with experimental data for a 45 deg sweptback wing. These results are in good agreement with the experimental flutter data which is the first step toward validating CAP-TSD for general transonic aeroelastic applications. The paper presents these results and comparisons along with general remarks regarding modern wing flutter analysis by computational fluid dynamics methods.
Bey, Kim S.; Scott, Robert C.; Bartels, Robert E.; Waters, William A.; Chen, Roger
The Space Shuttle tile overlay repair concept, developed at the NASA Johnson Space Center, is designed for on-orbit installation over an area of damaged tile to permit safe re-entry. The thin flexible plate is placed over the damaged area and secured to tile at discreet points around its perimeter. A series of flutter analyses were performed to determine if the onset of flutter met the required safety margins. Normal vibration modes of the panel, obtained from a simplified structural analysis of the installed concept, were combined with a series of aerodynamic analyses of increasing levels of fidelity in terms of modeling the flow physics to determine the onset of flutter. Results from these analyses indicate that it is unlikely that the overlay installed at body point 1800 will flutter during re-entry.
Everett, Thomas H; Olgin, Jeffrey E.
Atrial fibrillation (AF) is commonly associated with congestive heart failure (CHF), and CHF has been shown to be associated with atrial structural remodeling resulting in fibrosis. This atrial interstitial fibrosis has been seen in patients with CHF and animal models of pacing induced heart failure. With atrial fibrosis, conduction abnormalities result in an increase in AF vulnerability. The mechanism of AF that is associated with CHF is still under debate as both focal and reentrant mechani...
Wada, Yuko; Aiba, Takeshi; Tsujita, Yasuyuki; Itoh, Hideki; Wada, Mitsuru; Nakajima, Ikutaro; Ishibashi, Kohei; Okamura, Hideo; Miyamoto, Koji; Noda, Takashi; Sugano, Yasuo; Kanzaki, Hideaki; Anzai, Toshihisa; Kusano, Kengo; Yasuda, Satoshi
Background Landiolol effectively controls rapid heart rate in atrial fibrillation or flutter (AF/AFL) patients with left ventricular (LV) dysfunction. However, predicting landiolol Responders and Non-Responders and patients who will experience adverse effects remains a challenge. The aim of this study was to clarify the potential applicability of landiolol for rapid AF/AFL and refractory ventricular tachyarrhythmias (VTs) in patients with heart failure. Methods A total of 39 patients with AF/...
B. A. Khudayarov
Full Text Available The flutter of viscoelastic plates and cylindrical panels streamlined by a gas current are investigated. The basic direction of the present work consists in taking into account of viscoelastic material properties at supersonic speeds. An algorithm of the numerical solution for the problem has been worked out on the basic of the method. The results of the flutter critical speed calculations have been given.
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...
... page from the NHLBI on Twitter. How Can Atrial Fibrillation Be Prevented? Following a healthy lifestyle and taking ... risk for heart disease may help you prevent atrial fibrillation (AF). These steps include: Following a heart healthy ...
Jalife, José; Kaur, Kuljeet
The fundamental mechanisms governing the perpetuation of atrial fibrillation (AF), the most common arrhythmia seen in clinical practice, are poorly understood, which explains in part why AF prevention and treatment remain suboptimal. Although some clinical parameters have been identified as predicting a transition from paroxysmal to persistent AF in some patients, the molecular, electrophysiological, and inflammation changes leading to such a progression have not been described in detail. Oxidative stress, atrial dilatation, calcium overload, inflammation, microRNAs, and myofibroblast activation are all thought to be involved in AF-induced atrial remodeling. However, it is unknown to what extent and at which time points such alterations influence the remodeling process that perpetuates AF. Here we postulate a working model that might open new pathways for future investigation into mechanisms of AF perpetuation. We start from the premise that the progression to AF perpetuation is the result of interplay among manifold signaling pathways with differing kinetics. Some such pathways have relatively fast kinetics (e.g., oxidative stress-mediated shortening of refractory period); others likely depend on molecular processes with slower kinetics (e.g., transcriptional changes in myocyte ion channel protein expression mediated through inflammation and fibroblast activation). We stress the need to fully understand the relationships among such pathways should one hope to identify novel, truly effective targets for AF therapy and prevention. PMID:25661032
Lee-Rausch, Elizabeth M.; Batina, John T.
Modifications to an existing 3D implicit upwind Euler/Navier-Stokes code for the aeroelastic analysis of wings are described. These modifications include the incorporation of a deforming mesh algorithm and the addition of the structural equations of motion for their simultaneous time-integration with the governing flow equations. The paper gives a brief description of these modifications and presents unsteady calculations which check the modifications to the code. Euler flutter results for an isolated 45 deg swept-back wing are compared with experimental data for seven freestream Mach numbers which define the flutter boundary over a range of Mach number from 0.499 to 1.14. These comparisons show good agreement in flutter characteristics for freestream Mach numbers below unity. For freestream Mach numbers above unity, the computed aeroelastic results predict a premature rise in the flutter boundary as compared with the experimental boundary. Steady and unsteady contours of surface Mach number and pressure are included to illustrate the basic flow characteristics of the time-marching flutter calculations and to aid in identifying possible causes for the premature rise in the computational flutter boundary.
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...
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...
textabstractAtrial fibrillation is a common cardiac arrhythmia that is characterized by rapid disorganized atrial electrical activity resulting in absence of atrial contractions. It is diagnosed on the basis of typical findings on an electrocardiogram (ECG). The characteristic ECG findings are absence of P-waves, and an irregular heart rate. Symptoms of atrial fibrillation include palpitations, dyspnea, reduced exercise capacity, chest pain and dizziness, but it often goes without symptoms. A...
The only major and potentially fatal risk for patients with atrial fibrillation is the development of systemic thromboembolism. Stroke occurs five times more frequently in patients with atrial fibrillation than in comparable patients in sinus rhythm. The yearly incidence of stroke in atrial fibrilla
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.
Steinberg, Benjamin A; Piccini, Jonathan P
Atrial fibrillation increases the risk of stroke, which is a leading cause of death and disability worldwide. The use of oral anticoagulation in patients with atrial fibrillation at moderate or high risk of stroke, estimated by established criteria, improves outcomes. However, to ensure that the benefits exceed the risks of bleeding, appropriate patient selection is essential. Vitamin K antagonism has been the mainstay of treatment; however, newer drugs with novel mechanisms are also available. These novel oral anticoagulants (direct thrombin inhibitors and factor Xa inhibitors) obviate many of warfarin's shortcomings, and they have demonstrated safety and efficacy in large randomized trials of patients with non-valvular atrial fibrillation. However, the management of patients taking warfarin or novel agents remains a clinical challenge. There are several important considerations when selecting anticoagulant therapy for patients with atrial fibrillation. This review will discuss the rationale for anticoagulation in patients with atrial fibrillation; risk stratification for treatment; available agents; the appropriate implementation of these agents; and additional, specific clinical considerations for treatment. PMID:24733535
Zhang wei; Yang guirong; Zheng zhaotong; Wang sujia; Zhang yun
@@ Objective Integrin β1 regulates cell to cell and cell to extracellualr matrix interaction in heart. however, its pathop hysiological role in atrial fibrillation is unclear. The purpose of t his study was to determine whether atrial structural remodeling during atrial fibrillation is associated with altered integrinβ1.
BACKGROUND: Atrial fibrillation is the most common cardiac dysrhythmia and left atrial size is an important factor in the development of atrial fibrillation. In the presence of atrial fibrillation an increase in left atrial size is associated with increased risk of stroke as well as increased morbidity and mortality. In this context, this study entitled “relation between left atrial size and atrial fibrillation in different diseases” was undertaken to study the left atrial size in different d...
For a vibration system with 2-DOF of bend and torsion, itscritical flutter wind speed can be calculated by using complex mode frequency iteration (CMFI) method based on MatLab 5.2, the results of which are in agree with those acquired by wind tunnel test. Not only critical flutter wind speed, but also vibration characteristic of a system under different wind speeds can be determined. CMFI method is suitable for both of separated-flow torsional flutter and classic coupling flutter analysis, which is presented by flutter analysis of an ideal thin plate and a bluff bridge deck. Furthermore, it is proved through the investigation of the relationship between flutter derivatives and its critical flutter wind speed that coupling aerodynamic derivatives are necessary for classic coupling flutter to occur.
Njuguna, James A. K.
Emergence of flutter compromises not only the long-term durability of the wing structure, but also the operational safety, flight performance and energy efficiency of the aircraft. Effectual means of flutter prevention are, therefore, mandatory in the certification of new flight vehicles. This work intends to address the flutter phenomenon highlighting the above issues, and reviews some of the most recent theoretical and experimental developments in flutter analyses. In the ...
Kanjuro Makihara; Shigeru Shimose
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 att...
Rio Melvin Aro. T; EZHILMARAN G
Flutter is an unstable oscillation which can lead to destruction. Flutter can occur on fixed surfaces, such as blades, wing or the stabilizer. By self-excited aeroelastic instability, flutter can lead to mechanical or structural failure of aircraft engine blades. The modern engines have been designed with increased pressure ratio and reduced weight in order to improve aerodynamic efficiency, resulting in severe aeroelastic problems. Particularly flutter in axial compressors with t...
Llinares, Raul; Igual, Jorge
Atrial fibrillation disorders are one of the main arrhythmias of the elderly. The atrial and ventricular activities are decoupled during an atrial fibrillation episode, and very rapid and irregular waves replace the usual atrial P-wave in a normal sinus rhythm electrocardiogram (ECG). The estimation of these wavelets is a must for clinical analysis. We propose a new approach to this problem focused on the quasiperiodicity of these wavelets. Atrial activity is characterized by a main atrial rhythm in the interval 3-12 Hz. It enables us to establish the problem as the separation of the original sources from the instantaneous linear combination of them recorded in the ECG or the extraction of only the atrial component exploiting the quasiperiodic feature of the atrial signal. This methodology implies the previous estimation of such main atrial period. We present two algorithms that separate and extract the atrial rhythm starting from a prior estimation of the main atrial frequency. The first one is an algebraic method based on the maximization of a cost function that measures the periodicity. The other one is an adaptive algorithm that exploits the decorrelation of the atrial and other signals diagonalizing the correlation matrices at multiple lags of the period of atrial activity. The algorithms are applied successfully to synthetic and real data. In simulated ECGs, the average correlation index obtained was 0.811 and 0.847, respectively. In real ECGs, the accuracy of the results was validated using spectral and temporal parameters. The average peak frequency and spectral concentration obtained were 5.550 and 5.554 Hz and 56.3 and 54.4%, respectively, and the kurtosis was 0.266 and 0.695. For validation purposes, we compared the proposed algorithms with established methods, obtaining better results for simulated and real registers.
Asmar, Abdo; Ross, Edward A.
Despite transient hyperthyroidism reportedly occurring in ∼30% of post-parathyroidectomy (PTX) patients with primary hyperparathyroidism, it has rarely been described in the internal medicine literature. It occurs within days of surgery, is usually clinically mild or silent, and typically spontaneously resolves within weeks. Patients can, however, unusually present with symptoms and signs of thyrotoxicosis, including arrhythmias. We report a case of a hemodialysis patient who developed self-l...
The follow-up period was 3 years. After 6 months antiarrhythmic drugs (cordarone were cancelled, the patient no complains, at the control daily monitorings of an electrocardiogram by Holter methods rhythm disturbances haven’t been reported.
... regular beat. Certain cells in your heart make electric signals that cause the heart to contract and pump blood. These electrical signals show up on an elec- trocardiogram (ECG) recording. Your doctor can read your ECG to find out if the electric signals are normal. In atrial fibrillation (AFib), the ...
@@ Atrial fibrillation(AF) may occur in paroxysmaland persistent forms. It may be seen in normal subjects,particularly during emotional stress or follow-ing surgery,exercise, or acute alcoholic intoxication.It also may occur in patients with heart or lungdisease who develop acute hypoxia, hypercapnia,ormetabolic or hemodynamic derangements.
Wilson, William C.; Moore, Jason P.; Juarez, Peter D.
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.
Yu, Kaiping; Ye, Jiyuan; Zou, Jingxiang; Yang, Bingyuan; Yang, Hua
A modal parameter identification method of impulse response function, based on a modulated Gaussian wavelet transform, is presented. The factors influencing the identification accuracy and the required conditions of using this parameter identification method are discussed. Numerical verification of the proposed method is presented for several two-degree-of-freedom examples. A wind tunnel flutter experiment on a wing model of missiles is introduced. The data set from the flutter test is analyzed by using the proposed wavelet transform method. The first two order modal parameters of the wing model are identified, and then the critical dynamic stress is predicted by using the flutter stability parameter method. Finally, the results are compared with the results of FFT analysis.
The responses and limit cycle flutter of a plate-type structure with cubic stiffness in viscous flow were studied. The continuous system was dispersed by utilizing Galerkin Method. The equivalent linearization concept was performed to predict the ranges of limit cycle flutter velocities. The coupled map of flutter amplitude-equivalent linear stiffness-critical velocity was used to analyze the stability of limit cycle flutter. The theoretical results agree well with the results of numerical integration, which indicates that the equivalent linearization concept is available to the analysis of limit cycle flutter of plate-type structure. (authors)
Guruswamy, Guru P.
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.
Martin, Dennis J
Presented is a limited review of some experiences in flight testing of missiles and of wing flutter investigations that may be of interest in missile design. Several types of flutter of concern in missile studies are briefly described. Crude criteria are presented for two of the most common types of flutter to permit a rapid estimate to be made of the probability of the occurrence of flutter. Many of the details of the flutter problem have been omitted, and only the broader elements have been retained so as to give the designer an overall view of the subject.
Konopelchenko, B G
Gradient catastrophe and flutter instability in the motion of vortex filament within the localized induction approximation are analyzed. It is shown that the origin if this phenomenon is in the gradient catastrophe for the dispersionless Da Rios system which describes motion of filament with slow varying curvature and torsion. Geometrically this catastrophe manifests as a rapid oscillation of a filament curve in a point that resembles the flutter of airfoils. Analytically it is the elliptic umbilic singularity in the terminology of the catastrophe theory. It is demonstrated that its double scaling regularization is governed by the Painlev\\'e-I equation.
Vatne, Sigrid Ringdalen
The goal of this thesis is to evaluate if flutter is a challenge to a 10 MW wind turbine. Flutter is an aeroelastic instability which occurs due to the interaction between the aerodynamic forces and the elasticity of the blade. Torsional motions of the blade lead to variations in the aerodynamic forces due to changes in the angle of attack of the airfoil. The variation in aerodynamic forces creates flapwise vibration of the blade. When the vibrations of the blades are in an unfavourable phase...
Gradient catastrophe and flutter instability in the motion of a vortex filament within the localized induction approximation are analyzed. It is shown that the origin of this phenomenon is in the gradient catastrophe for the dispersionless Da Rios system which describes the motion of a filament with slow varying curvature and torsion. Geometrically, this catastrophe manifests as a rapid oscillation of a filament curve in a point that resembles the flutter of airfoils. Analytically, it is the elliptic umbilic singularity in the terminology of the catastrophe theory. It is demonstrated that its double scaling regularization is governed by the Painleve-I equation. (fast track communication)
Konopelchenko, B G [Dipartimento di Fisica, Universita del Salento and INFN, Sezione di Lecce, 73100 Lecce (Italy); Ortenzi, G, E-mail: firstname.lastname@example.org [Dipartimento di Matematica Pura ed Applicazioni, Universita di Milano Bicocca, 20125 Milano (Italy)
Gradient catastrophe and flutter instability in the motion of a vortex filament within the localized induction approximation are analyzed. It is shown that the origin of this phenomenon is in the gradient catastrophe for the dispersionless Da Rios system which describes the motion of a filament with slow varying curvature and torsion. Geometrically, this catastrophe manifests as a rapid oscillation of a filament curve in a point that resembles the flutter of airfoils. Analytically, it is the elliptic umbilic singularity in the terminology of the catastrophe theory. It is demonstrated that its double scaling regularization is governed by the Painleve-I equation. (fast track communication)
Baker, Camille; Sicchio, Kate; Mooney, Tara Baoth; Stewart, Rebecca
Flutter/Stutter is an improvisational dance piece, part of the Hacking the Body 2.0 project, that uses networked soft circuit sensors to trigger sound and haptic actuators in the form of a small motor that tickles the performers. Dancers embody the flutter of the motor and respond with their own movement that reflects this feeling. This research explores using the concept of hacking data to repurpose and re-imagine biofeedback from the body. It investigates understandings of states of the bo...
Baker, Camille; Sicchio, Kate; Mooney, Tara Baoth; Stewart, Rebecca
Flutter/Stutter is an improvisational dance piece, part of the Hacking the Body 2.0 project, that uses networked soft circuit sensors to trigger sound and haptic actuators in the form of a small motor that tickles the performers. Dancers embody the flutter of the motor and respond with their own movement that reflects this feeling. This research explores using the concept of hacking data to repurpose and re-imagine biofeedback from the body. It investigates understandings of states of the bod...
Edwards, J. W.
Flight flutter test results of the first aeroelastic research wing of NASA's Drones for Aerodynamic and Structural Testing (DAST) program are presented. The implementation of the flutter suppression system and the flight test operation are described. The conduct of the flutter testing and the near-real time damping estimation algorithm are also described in detail. Flight data was obtained at Mach numbers up to 0.91 and was of high quality. Response to fast frequency sweep excitation provided reliable damping estimates and the open-loop flutter boundary was well defined. Evidence of angle-of-attack effects upon damping at high transonic Mach numbers is also presented. While the flutter suppression system provided augmented damping at speeds below the flutter boundary, an error in the implementation of the system gain caused the system to be less stable than predicted and the vehicle encountered system-on flutter on the third flight.
Roberto A.Franken; Ronaldo F.Rosa; Silvio CM Santos
This review discusses atrial fibrillation according to the guidelines of Brazilian Society of Cardiac Arrhythmias and the Brazilian Cardiogeriatrics Guidelines. We stress the thromboembolic burden of atrial fibrillation and discuss how to prevent it as well as the best way to conduct cases of atrial fibrillatios in the elderly, reverting the arrhythmia to sinus rhythm, or the option of heart rate control. The new methods to treat atrial fibrillation, such as radiofrequency ablation, new oral direct thrombin inhibitors and Xa factor inhibitors, as well as new antiarrhythmic drugs, are depicted.
ens Rokkedal Nielsen, MD; Kristian Wachtel, MD PhD; Jawdat Abdulla, MD, PhD
Aim: 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
Vergara, Pasquale; Della Bella, Paolo
Atrial fibrillation (AF) is associated with increases in the risk of mortality, congestive heart failure, and stroke. Medical treatment is aimed at preventing thrombo-embolic complications and reducing symptoms and consequences related to the arrhythmia. In the first section of this review, we discuss the principles of mainstream oral anticoagulant therapy and the possible advantages of the new oral anticoagulants. In the second section, we review the catheter ablation approaches to paroxysma...
Pêgo-Fernandes Paulo M.
Full Text Available Benign cardiac tumors are rare, and lipomas are among those less frequently found. We report the case of a 48-year-old male complaining of high blood pressure and epistaxis in the last 2 months, with a diagnosis of right atrial lipoma established on echocardiography, magnetic resonance imaging, and anatomicopathological examination. The tumor was successfully removed, and up to 42 months after surgical excision, no evidence of tumor relapse was observed.
Ahmad, Yousif; YH Lip, Gregory
Patients with atrial fibrillation (AF) are at increased thromboembolic risk, and they suffer more severe strokes with worse outcomes. Most thromboembolic complications of AF are eminently preventable with oral anticoagulation, and the increasing numbers of AF patients mean antithrombotic therapy is the most crucial management aspect of this common arrhythmia. Despite the proven efficacy of warfarin, a string of limitations have meant that it is underused by physicians and patients alike. This...
Giorgi MA; Miguel LS
Mariano A Giorgi,1,2 Lucas San Miguel31Cardiology Service, Centro de Educación Médica e Investigaciones Clínicas “Norberto Quirno”, 2Department of Pharmacology, School of Medicine, Universidad Austral, 3Department of Cardiology and Cardiovascular Surgery, FLENI, Buenos Aires, ArgentinaAbstract: Warfarin is the traditional therapeutic option available to manage thromboembolic risk in atrial fibrillation. The hemorrhagic risk with warfarin de...
Francis E. Marchlinski
Full Text Available Atrial fibrillation (AF is a supraventricular tachyarrhythmia characterized by uncoordinated atrial activation. On the ECG fibrillatory (f waves (rapid oscillations with variable amplitude, shape and timing replace normal P waves. Ventricular response becomes irregular and rapid depending of the intrinsic electrophysiological properties of the AV node1 and the balance between vagal and sympathetic tone1. The presence of an irregularly pulse is a clinical sign that can be quickly and reliably identified in any healthcare situation and, indicates AF with a high sensitivity and specificity (95% and 75%, respectively. If the irregularity last for more than 20 seconds the specificity reaches 98% 2-4. Identification of AF can be done by using manual pulse palpation in those presenting with a variety of symptoms. It is desirable to check the blood pressure and pulse in all patients who present with breathlessness, dyspnea, palpitations, syncope, dizziness or chest discomfort. Furthermore, many patients presenting with an acute stroke are found to be in AF albeit asymptomatic with respect to non-neurologic complaints. The finding of a sustained irregular wide QRS complex tachycardia may be suspicious of AF conducted with bundle brunch aberrancy or over an accessory pathway, and in patients with A-V sequential pacemakers can reflect an inadequate configuration with ventricular tracking of sensed atrial activity.
Maharani, Nani; Kuwabara, Masanari; Hisatome, Ichiro
The importance of atrial fibrillation (AF) as a cause of mortality and morbidity has prompted research on its pathogenesis and treatment. Recognition of AF risk factors is essential to prevent it and reduce the risk of death. Hyperuricemia has been widely accepted to be associated with the incidence of paroxysmal or persistent AF, as well as to the risk of AF in post cardiovascular surgery patients. The possible explanations for this association have been based on their relation with either oxidative stress or inflammation. To investigate the link between hyperuricemia and AF, it is necessary to refer to hyperuricemia-induced atrial remodeling. So far, both ionic channel and structural remodeling caused by hyperuricemia might be plausible explanations for the occurrence of AF. Inhibition of xanthine oxidase and nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase, or the use of antioxidants, along with serum uric acid (SUA) level reduction to prevent inflammation, might be useful. Uric acid transporters (UATs) play a key role in the regulation of intracellular uric acid concentration. Intracellular rather than serum uric acid level is considered more important for the pathogenesis of AF. Identification of UATs expressed in cells is thus important, and targeting UATs might become a potential strategy to reduce the risk of hyperuricemia-induced atrial fibrillation. PMID:27396561
Spronk, Henri M H; De Jong, Anne Margreet; Verheule, Sander; De Boer, Hetty C; Maass, Alexander H; Lau, Dennis H; Rienstra, Michiel; van Hunnik, Arne; Kuiper, Marion; Lumeij, Stijn; Zeemering, Stef; Linz, Dominik; Kamphuisen, Pieter Willem; Ten Cate, Hugo; Crijns, Harry J; Van Gelder, Isabelle C; van Zonneveld, Anton Jan; Schotten, Ulrich
AIMS: Atrial fibrillation (AF) produces a hypercoagulable state. Stimulation of protease-activated receptors by coagulation factors provokes pro-fibrotic, pro-hypertrophic, and pro-inflammatory responses in a variety of tissues. We studied the effects of thrombin on atrial fibroblasts and tested the
Tzikas, Apostolos; Shakir, Samera; Gafoor, Sameer;
Aims: To investigate the safety, feasibility, and efficacy of left atrial appendage occlusion (LAAO) with the AMPLATZER Cardiac Plug (ACP) for stroke prevention in patients with atrial fibrillation (AF). Methods and results: Data from consecutive patients treated in 22 centres were collected. A...
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
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. PMID:25247474
The effect of shape memory alloys (SMA) on the linear and nonlinear flutter behaviors of buckled cross-ply and angle-ply laminates was investigated in the frequency and time domains using the finite element method. In particular, this study takes the first move toward examining the effect of varying the SMA fiber spacing. Von Karman large deformation assumptions and quasi-steady aerodynamic theory were employed. The flutter boundary, stability boundary, time history response, and phase plane plots of SMA reinforced cross-ply and angle-ply laminates are presented. The numerical results show that increase in the SMA fiber volume fraction and prestrain may generate more recovery stress, and increase the stiffness of the SMA reinforced laminates. Therefore, the flutter boundary and critical load of the plate may be increased significantly. All five types of panel behavior, namely flat, buckled, limit-cycle, periodic, and chaotic motion, are clearly displayed and successively identified. This study sheds light on improving the flutter boundary efficiently by increasing the SMA fiber volume fraction to reinforce the center of the plate. (paper)
The hypothesis that stochastic magnetic fields disrupt zonal flows associated with ion temperature gradient turbulence saturation is investigated analytically with a residual flow calculation in the presence of magnetic flutter. The calculation starts from the time-asymptotic zero-beta residual flow of Rosenbluth and Hinton [Phys. Rev. Lett. 80, 724 (1998)] with the sudden application of an externally imposed, fixed magnetic field perturbation. The short-time electron response from radial charge loss due to magnetic flutter is calculated from the appropriate gyrokinetic equation. The potential evolution has quadratic behavior, with a zero crossing at finite time. The crossing time and its parametric dependencies are compared with numerical results from a gyrokinetic simulation of residual flow in the presence of magnetic flutter. The numerical and analytical results are in good agreement and support the hypothesis that the high-beta runaway of numerical simulations is a result of the disabling of zonal flows by finite-beta charge losses associated with magnetic flutter
Terry, P. W.; Pueschel, M. J.; Carmody, D. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Nevins, W. M. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)
The hypothesis that stochastic magnetic fields disrupt zonal flows associated with ion temperature gradient turbulence saturation is investigated analytically with a residual flow calculation in the presence of magnetic flutter. The calculation starts from the time-asymptotic zero-beta residual flow of Rosenbluth and Hinton [Phys. Rev. Lett. 80, 724 (1998)] with the sudden application of an externally imposed, fixed magnetic field perturbation. The short-time electron response from radial charge loss due to magnetic flutter is calculated from the appropriate gyrokinetic equation. The potential evolution has quadratic behavior, with a zero crossing at finite time. The crossing time and its parametric dependencies are compared with numerical results from a gyrokinetic simulation of residual flow in the presence of magnetic flutter. The numerical and analytical results are in good agreement and support the hypothesis that the high-beta runaway of numerical simulations is a result of the disabling of zonal flows by finite-beta charge losses associated with magnetic flutter.
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 includi...
Cazier, F. W., Jr.; Kehoe, M. W.
Flight tests were performed on an F-16 airplane carrying on each wing an AIM-9J wingtip missile, a GBU-8 bomb near midspan, and an external fuel tank. Baseline flights with the GBU-8 mounted on a standard pylon established that this configuration is characterized by an antisymmetric limited amplitude flutter oscillation within the operational envelope. The airplane was then flown with GBU-8 mounted on the decoupler pylon. The decoupler pylon is a NASA concept of passive wing-store flutter suppression achieved by providing a low store-pylon pitch frequency. The decoupler pylon successfully suppressed wing-store flutter throughout the flight envelope. A 37 percent increase in flutter velocity over the standard pylon was demonstrated. Maneuvers with load factors to 4g were performed. Although the static store displacements during maneuvers were not sufficiently large to be of concern, a store pitch alignment system was tested and performed successfully. One GBU-8 was ejected demonstrating that weapon separation from the decoupler pylon is normal.
Cooper, P. A.; Stroud, W. J.
The results of an analytical study are presented on the use of boron polyimide filamentary composite material for the purpose of increasing the flutter speed of a simple titanium full depth sandwich wing structure designed for strength. The results clearly demonstrate that selective reinforcement of wing surfaces, using judiciously placed filamentary composites, promises sizable mass savings in the design of advanced aircraft structures.
Remes, J.; Brakel, T.J. van; Bolotin, G.; Garber, C.; Jong, MM de; Veen, FH van der; Maessen, J.G.
OBJECTIVES: Atrial dilatation predisposes to atrial fibrillation. Although several animal models focus on the initiating mechanisms of atrial fibrillation in dilated atria, a model of left atrial overload resulting in persistent atrial fibrillation in nonanesthetized animals has not been presented t
HAN Wei; LI Wei-min; ZHOU Hong-yan; HUO Hong; WEI Na; DONG Guo; CAO Yong; ZHOU Guo; YANG Shu-sen
@@ Atrial fibrillation (AF) is one of the most common arrhythmias in clinical practice. AF results in electrophysiological alterations which involve increased atrial effective refractory period and atrial effective refractory period dispersion, reduced rate adaptation of atrial effective refractory period, and slowed atrial conduction.
John, Roy M; Kumar, Saurabh
Although sinus node dysfunction (SND) and atrial arrhythmias frequently coexist and interact, the putative mechanism linking the 2 remain unclear. Although SND is accompanied by atrial myocardial structural changes in the right atrium, atrial fibrillation (AF) is a disease of variable interactions between left atrial triggers and substrate most commonly of left atrial origin. Significant advances have been made in our understanding of the genetic and pathophysiologic mechanism underlying the development and progression of SND and AF. Although some patients manifest SND as a result of electric remodeling induced by periods of AF, others develop progressive atrial structural remodeling that gives rise to both conditions together. The treatment strategy will thus vary according to the predominant disease phenotype. Although catheter ablation will benefit patients with predominantly AF and secondary SND, cardiac pacing may be the mainstay of therapy for patients with predominant fibrotic atrial cardiomyopathy. This contemporary review summarizes current knowledge on sinus node pathophysiology with the broader goal of yielding insights into the complex relationship between sinus node disease and atrial arrhythmias. PMID:27166347
Page, Richard L; Connolly, Stuart J; Crijns, Harry J G M;
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...... 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....
Michelle M Jennings; J Kevin Donahue
Atrial fibrillation significantly contributes to mortality and morbidity through increased risk of stroke, heart failure and myocardial infarcts. Investigations of mechanisms responsible for the development and maintenance of atrial fibrillation have highlighted the importance of gap junctional remodeling. Connexins 40 and 43, the major atrial gap junctional proteins, undergo considerable alterations in expression and localization in atrial fibrillation, creating an environment conducive to s...
Berglund, H; Boukter, S; Theodorsson, E; Vallin, H; Edhag, O
The aim of the present study was to determine whether left atrial size--a likely indicator of atrial stretching--correlates with the plasma concentration of atrial natriuretic peptide and whether this relation is different in patients in sinus rhythm and in those with atrial fibrillation. Arterial plasma concentrations of immunoreactive atrial natriuretic peptide (ir-ANP), adrenaline, noradrenaline, aldosterone, and vasopressin were measured in 13 patients in sinus rhythm without apparent hea...
Levy, T; Walker, S; Rex, S; Rochelle, J; Paul, V.
OBJECTIVE—To evaluate the incremental antifibrillatory effect of multisite atrial pacing compared with right atrial pacing in patients with drug refractory paroxysmal atrial fibrillation paced for arrhythmia prevention alone. METHODS—In 20 of these patients (mean (SD) age 64 (8) years; 14 female, six male), a single blinded randomised crossover study was performed to investigate the incremental benefit of one month of multisite atrial pacing compared with one month of right atrial pacing. Out...
Kamel, Hooman; Okin, Peter M.; Longstreth, W. T.; Elkind, Mitchell S.V.; Soliman, Elsayed Z.
Atrial fibrillation (AF) has long been associated with a heightened risk of ischemic stroke and systemic thromboembolism, but recent data require a re-evaluation of our understanding of the nature of this relationship. New findings about the temporal connection between AF and stroke, alongside evidence linking markers of left atrial abnormalities with stroke in the absence of apparent AF, suggest that left atrial thromboembolism may occur even without AF. These observations undermine the hypothesis that the dysrhythmia that defines AF is necessary and sufficient to cause thromboembolism. In this commentary, we instead suggest that the substrate for thromboembolism may often be the anatomic and physiological atrial derangements associated with AF. Therefore, our understanding of cardioembolic stroke may be more complete if we shift our representation of its origin from AF to the concept of atrial cardiopathy. PMID:26021638
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.
Nailu Li; Balas, Mark J.; Pourya Nikoueeyan; Hua Yang; Naughton, Jonathan W.
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...
John D. Gill; Capece, Vincent R.; Ronald B. Fost
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 freque...