Electrophysiologic Study and Radiofrequency Catheter Ablation of Isthmus-Independent Atrial Flutter

INTRODUCTION: We report the electrophysiologic study and radiofrequency catheter ablation of isthmus-independent atrial flutter in 2 patients. The isthmus-independent atrial flutter in these 2 patients had similar ECG and electrophysiologic findings. Both were reproducibly induced by rapid atrial pacing. The atrial activation sequence and entrainment study proved that these atrial flutters were not isthmus-dependent. A high-right atrial site was identified as the critical site of the slow conduction zone of the tachycardia in both. This site showed double potentials and mid-diastolic potentials. Radiofrequency catheter ablation at this site successfully eliminated the isthmus-independent atrial flutter in both patients.     

Electrocardiographic Patterns and Results of Radiofrequency Catheter Ablation of Clockwise Type I Atrial Flutter

Clockwise Rotation of Atrial Flutter. Introduction: Counterclockwise right atrial propagation is usually observed in common atrial flutter, but little is known regarding flutter with clockwise right atrial rotation. The aim of this study is to describe the ECG characteristics and results of catheter ablation of atrial flutter with clockwise right atrial rotation.
Methods and Results: Among the 38 patients with type I atrial flutter in this study population, right atrial impulse propagation was counterclockwise in 20 and clockwise in 8. In the remaining 10 patients, both clockwise and counterclockwise patterns were seen. Clinical and ECG parameters associated with clockwise flutter were compared to those of 28 cases of counterclockwise atrial flutter. Ablation was performed in 11 of 18 cases using a technique identical to that used for counterclockwise flutter. A classical "sawtooth" pattern of the flutter wave was observed in 28 of 28 counterclockwise and 14 of 18 clockwise flutter. A shorter plateau phase, a widening of the negative component of the F wave in the inferior leads, and a negative F wave in V₁ were the most consistent findings in clockwise flutter. Coronary sinus recording always showed septal to lateral left atrial impulse propagation. Ablation was successful in 11 of 11 cases of clockwise flutter in whom this procedure was performed, with 9.5 ± 11.6 radiofrequency pulses delivered between the tricuspid valve and the coronary sinus ostium (n = 5) or the inferior vena cava (n = 5), and in the proximal coronary sinus (n = 1). After a follow-up of 46.6 weeks, two recurrences of clockwise flutter were encountered, which were successfully treated with a second session.
Conclusion: Contrary to commonly accepted concepts, clockwise rotation of atrial flutter Ls not an infrequent phenomenon and can mimic counterclockwise rotation. It can also be successfully ablated by radiofrequency pulses.     

Effects of High-Frequency Atrial Pacing in Atypical Atrial Flutter and Atrial Fibrillation

Atypical atrial flutter has, hitherto, been relatively refractory totermination by rapid atrial pacing. High-frequency pacing (HFP) in theatrium, for termination of atrial flutter or atrial fibrillation (AF), andthe electrophysiologic effects related to it have not been examined. Weexamined the clinical efficacy, safety, and electrophysiologic mechanisms ofHFP using 50-Hz bursts at 10 mA applied at the high right atrium in patientswith atypical atrial flutter (group 1) or AF (group 2), using a prospectiverandomized study protocol. Four burst durations (500, 1000, 2000, and 4000ms) were applied at the high right atrium repetitively in random sequence in22 patients with spontaneous atrial flutter or AF. Local and distant rightand left atrial electrogram recordings were analyzed during and after HFP.HFP resulted in local and distant right and left atrial electrogramacceleration in 8 of 10 patients (80%) in group 1 but caused lessfrequent local atrial electrogram acceleration (6 of 12 patients) and nodistant atrial electrogram effects in group 2 (p < .05 versus group 1).The HFP protocol was effective in arrhythmia termination in 6 of 10patients in group 1 but in no patient in group 2 (p < .05 versus group1). Standard HFP protocol applied at the high right atrium can frequentlyalter atrial activation in both atria and can terminate atypical atrialflutter. Efficacy in AF is limited, probably due to limitedelectrophysiologic actions beyond the local pacing site.     

Response of narrow QRS tachycardia in a patient with surgical closure of atrial septal defect to atrial overdrive pacing: What is the mechanism?

A 57‐year old woman who had pericardial patch closure of ostium secundum atrial septal defect (ASD) at the age of 23 years presented with shortness of breath. Her echocardiogram showed no residual ASD, good biventricular function and normal pulmonary artery pressures.     

Ablation of atypical atrial flutter guided by the use of concealed entrainment in patients without prior cardiac surgery

INTRODUCTION: Mapping techniques have not been systematically evaluated with respect to atypical atrial flutter (AF) not involving the inferior vena cava isthmus. The purpose of this study was to assess prospectively the use of concealed entrainment (CE) in mapping of AF and to assess the clinical benefit of ablation of clinically relevant atypical AF. METHODS AND RESULTS: In seven consecutive patients without prior cardiac surgery presenting with atypical AF, mapping was performed in the right and, if necessary, left atrium. At sites with CE, radiofrequency energy was delivered. In a posthoc analysis, the endocardial activation time, stimulus-flutter wave (F) interval, presence of split potentials and diastolic potentials, and postpacing interval were assessed, and effective sites were compared to ineffective sites. A total of 22 forms of atypical AF either could be induced or were present at the time of the study. Eleven of the 13 targeted atypical AFs (85%) were successfully ablated. The positive predictive value of CE increased from 45% to 75% in the presence of matching electrogram-F and stimulus-F intervals or if flutter terminated during entrainment pacing, and to 88% in the presence of split atrial electrograms or diastolic potentials. During short-term clinical follow-up, none of the patients had recurrence of the ablated AF. However, the majority of patients required either medication for atrial fibrillation or repeated interventions for new forms of AF. CONCLUSION: Mapping and ablation of atypical AF is feasible if sites with CE can be identified. However, the clinical benefit of successful ablations in patients with atypical flutter appears to be limited.     

不纯心房扑动发生机制的心内电生理探讨

目的：心内电生理检查研究体表心电图不纯心房扑动的可能发生机制。方法6例患者经体表心电图证实有不纯心房扑动,射频消融时进行了心内电生理检查,并进行峡部阻断法消融心房扑动。结果：体表心电图与心心内电图同步记录证实,6例不纯心房扑动发作时均为右心房扑动、左心房颤动的心房脱节,心房扑动射频消融均获成功。随访期中2例复发,再次消融成功。结论：不纯心房扑动的发生可能是在右心房扑动的同时,左心房发生一过性颤动的结果。     

Electrophysiologic characteristics and ablation of an atypical atrial flutter in the right atrium

Subeustachian isthmus-dependent typical atrial flutter has been well studied. We demonstrate a case with atypical atrial flutter involving only the base of the right atrium around the inferior vena cava. Entrainment pacing and mapping studies documented a distinct circuit traversing the subeustachian isthmus, propagating through the posterobasal right atrium, and skirting the inferior vena cava. Successful radiofrequency ablation of the arrhythmia was accomplished by creating a linear lesion at the subeustachian isthmus. Mapping of the inferior vena cava region and the demonstration of concealed entrainment are essential steps in establishing the mechanism of the atypical atrial flutter.     

Predictors of failure of transoesophageal cardioversion of common atrial flutter.

BACKGROUND: Common atrial flutter is due to a re-entry circuit in the right atrium. It is possible to entrain and interrupt this arrhythmia with transoesophageal pacing (TEAP) in a substantial percentage of patients. The aim of this study is to evaluate factors associated with failure of transoesophageal cardioversion of common atrial flutter. METHODS: One hundred consecutive patients underwent an attempted transoesophageal cardioversion of their common atrial flutter. In order to detect factors associated with failure of this procedure, the following were considered: (a) age and gender; (b) underlying heart disease; (c) time of onset of the arrhythmia; (d) antiarrhythmic treatment at the time of cardioversion; (e) flutter cycle length, (f) A/V deflection ratio at the site of transoesophageal pacing; and (g) longitudinal and transverse diameters of right and left atrium on the echocardiogram. RESULTS: In 84 of 100 patients, TEAP modified the atrial flutter circuit: in 23 of these, sinus rhythm was restored; in 31 patients, flutter was converted into atrial fibrillation which spontaneously reverted to sinus rhythm; and in remaining 30 patients, persistent atrial fibrillation was obtained. In 16 cases, no modification in atrial flutter circuit was obtained by TEAP (Group 2). Using univariate analysis, this group of patients showed no significant difference in flutter cycle length, a smaller A/V ratio at the site of TEAP, a longer transverse diameter of left atrium and a shorter transverse diameter of right atrium. Analysis of the therapy at cardioversion shows that no Group 2 patients was on intravenous amiodarone, while a greater percentage of patients of the former group was on chronic amiodarone treatment. A logistic regression model applied to the data showed that flutter cycle length, transverse diameter of left atrium and A/V deflection ratio at the site of TEAP were independent variables with influence on the failure rate. CONCLUSION: Transoesophageal pacing is able to modify the circuit of common atrial flutter in a large percentage of patients, and can convert this arrhythmia to sinus rhythm in more than 50% of cases. Failure of this procedure is associated with electrophysiological parameters (flutter cycle length, A/V ratio at the site of TEAP), anatomical factors (left and right atrial diameters) and treatment in use at the time of TEAP.     

Radiofrequency ablation for cure of atrial flutter

Abstract Background: Atrial flutter is a common arrhythmia which frequently recurs after cardioversion and is relatively difficult to control with antiarrhythmic agents.
Aims: To evaluate the success rate, recurrence rate and safety of radiofrequency (RF) ablation for atrial flutter in a consecutive series of patients with drug refractory chronic or paroxysmal forms of the arrhythmia.
Methods: Electrophysiologic evaluation of atrial flutter included activation mapping with a 20 electrode halo cadieter placed around the tricuspid annulus and entrainment mapping from within the low right atrial isthmus. After confirmation of the arrhythmia mechanism with these techniques, an anatomic approach was used to create a linear lesion between the inferior tricuspid annulus and the eustachian ridge at the anterior margin of the inferior vena cava. In order to demonstrate successful ablation, mapping techniques were employed to show that bi-directional conduction block was present in the low right atrial isthmus.
Results: Successful ablation was achieved in 26/27 patients (96%). In one patient with a grossly enlarged right atrium, isthmus block could not be achieved. Of the 26 patients with successful ablation, mere has been one recurrence of typical flutter (4%) during a mean follow-up period of 5.5±2.7 months. This patient underwent a successful repeat ablation procedure. Of eight patients with documented clinical atrial fibrillation (in addition to atrial flutter) prior to the procedure, five continued to have atrial fibrillation following the ablation. There were no procedural complications and all patients had normal AV conduction at the completion of the ablation.
Conclusions: RF ablation is a highly effective and safe procedure for cure of atrial flutter. In patients with chronic or recurrent forms of atrial flutter RF ablation should be considered as a first line therapeutic option.     

Catheter Ablation of Atrial Tachycardia Following Atrial Fibrillation Ablation

Atrial tachycardias represent the second front of atrial fibrillation (AF) ablation. They are frequently encountered during the index ablation for patients with persistent AF and are common following ablation of persistent AF, occurring in half of all patients who have had AF successfully terminated. An atrial tachycardia is rightly seen as a failure of AF ablation, as these tachycardias are poorly tolerated by patients. This article describes a simple, practical approach to diagnosis and ablation of these atrial tachycardias.     

心房扑动与左、右心房扩大的关系

目的 探讨心房扑动与双心房扩大的关系.方法 对2006年1月～2010年3月在我院住院的1159例心房扑动者,通过彩色超声心动图(UCG)测量心脏左右心房内径,研究与相应疾病的关系.结果 1159例心房扑动者男性多于女性.冠心病者538例(占46.4%).UCG测量左心房内径值为28～79(平均57.87±10.11)mm.右房内径值为32～68(平均46.32±9.53)mm.其中850例左心房内径≥38mm及或右心房内径≥40mm,与内径正常者比,有统计学意义.结论 提示心房扑动与左、右心房扩大相关.左心房扩大例数与右心房扩大例数比,有统计学意义,提示左房扩大比右房扩大明显.     

Atrial Appendage Thrombosis Risk Is Lower for Atrial Flutter Compared with Atrial Fibrillation

Background

The risk of stroke and thromboembolism in atrial fibrillation is established. However, the evidence surrounding the risk of thromboembolism in patients with atrial flutter is not as clear. We hypothesized that atrial flutter would have indicators of less risk for thromboembolism compared with atrial fibrillation on transesophageal echocardiography, thereby possibly leading to a lower stroke risk.

心房颤动左心房内线性消融后的非典型性心房扑动

目的　左心房线性消融治疗心房颤动 (AF)后的非典型性心房扑动 (AAF)值得引起重视。方法　 2 4例患者 (男性 2 0例 ,女性 4例 ) ,年龄平均 5 1 2± 10 9(2 2～ 6 7)岁 ,左心房内径 33 9± 5 5(2 2～ 4 2 )mm。其中阵发性AF(PAF) 19例 ,持续性AF 5例。均在非接触式标测的指导下在左、右肺静脉口外进行环行消融 ,并在顶部肺静脉口间及二尖瓣环峡部行线性消融。在AF终止后经冠状静脉窦进行程序刺激以检验效果并观察是否存在AAF。结果　全部 19例PAF患者中 ,18例的左心房内线性消融获即时成功 ,1例经体外电转复 ;5例持续性AF者有 4例在消融后电转复成功 ,1例未能转复。共有 5例诱发出左心房AAF ,1例被超速抑制 ,2例在左心房顶部左、右肺静脉口之间 ,2例在二尖瓣峡部消融终止了AAF。在随访 7 5± 7(1～ 30 )月 ,除在肺静脉口间消融成功的 2例之外 ,其余 3例AAF均复发 ,2例服抗心律失常药物控制可维持窦性心律为主 ,1例因为 4∶1AV传导无症状而不愿接受治疗。结论　在左心房内进行线性消融治疗房颤存在引发非典型性房扑的可能 ,所采用的消融导管类型可能对其也存在一定影响 ,值得重视     

Incidence and clinical significance of transformation of atrial fibrillation to atrial flutter in patients undergoing long-term antiarrhythmic drug treatment.

AIMS: To investigate the rate of transformation of atrial fibrillation to atrial flutter in patients taking antiarrhythmic drugs for the prophylaxis of atrial fibrillation, we retrospectively analysed data from 305 consecutive patients with paroxysmal atrial fibrillation (155 male; mean age 63 +/- 11 years) treated with ventricular rate controlling drugs, antiarrhythmic drugs, or without drugs. METHODS AND RESULTS: At a mean follow-up of 9 months (range 1-24) all patients experienced recurrence of arrhythmia: 48 (14.6%, Group A) suffered Type 1 atrial flutter, and 257 (85.4%, Group B) atrial fibrillation. The relative rate of recurrence of atrial flutter vs atrial fibrillation was similar in patients without treatment or with ventricular rate controlling drugs (from 6.8% to 14.6%, P=ns). However, recurrence was higher (25%) in patients administered antiarrhythmic drug therapy. The relative risk in these patients was 3.02 times greater, compared with patients without treatment, or treated with rate controlling drugs (P<0.001). There were no differences between groups concerning the baseline clinical characteristics and the clinical consequences of the recurrence; patients with atrial flutter had a lower rate of conversion to sinus rhythm (42% vs 64%) and a higher rate of hospital admission (69% vs 36%) compared with those with atrial fibrillation. Six patients (8.5%) experienced 1:1 atrioventricular conduction during atrial flutter with a ventricular rate of 240-280 beats x min(-1). CONCLUSION: Our data suggest that the use of antiarrhythmic drugs for the prophylaxis of atrial fibrillation is associated with a threefold increase in the probability of Type 1 atrial flutter recurrence, as opposed to atrial fibrillation, which may have important clinical consequences, but which did not in our study.