Catheter ablation of long-lasting persistent atrial fibrillation: clinical outcome and mechanisms of subsequent arrhythmias

BACKGROUND: Catheter ablation of atrial fibrillation (AF) is challenging in patients with long-standing persistent AF. The clinical outcome and subsequent arrhythmia recurrence after using an ablation method targeting multiple left atrial sites with the aim of achieving acute AF termination has not been characterized. METHODS: Sixty patients (mean age: 53 +/- 9 years) with persistent AF (mean duration: 17 +/- 27 months) were prospectively followed after catheter ablation. Catheter ablation targeting the following sites was performed in a random sequence: (i) electrical isolation of all pulmonary veins (PV); (ii) disconnection of other thoracic veins; (iii) atrial ablation at sites possessing complex electrical activity, activation gradients, or short cycle lengths. Finally, linear ablation of the LA roof and mitral isthmus was performed if sinus rhythm was not restored following energy delivery to the above sites. At 1, 3, 6, and 12 months after ablation, patients underwent clinical review and 24-hour ambulatory ECG monitoring to identify asymptomatic arrhythmia. Repeat mapping and catheter ablation was performed in any patient experiencing recurrent atrial tachycardia (AT). Clinical success was defined as the absence of any sustained atrial arrhythmia. RESULTS: AF terminated during ablation in 52 patients (87%). The fluoroscopy and procedural durations were 84 +/- 30 minutes and 264 +/- 77 minutes, respectively. Three months after ablation, sustained ATs were documented in 24 patients (associated with AF in 2). Mapping in 23 patients showed a single AT in 7 while multiple ATs were observed in 16. Macroreentry was confirmed to be due to gaps in the ablation lines, while focal ATs originated from discrete sites or isthmuses near the left atrial appendage, coronary sinus, pulmonary veins, or fossa ovalis; these sites were similar to those at which the greatest impact was observed on the fibrillatory process during the initial ablation procedure. After repeat ablation, at 11 +/- 6 months of follow-up, 57 patients (95%) were in sinus rhythm and 3 developed recurrent AF or AT. All patients in sinus rhythm demonstrated improved exercise capacity and all but 2 had evidence of atrial transport as assessed by Doppler echocardiography (mitral A wave velocity 34 +/- 17 cm/sec) by 6 months. CONCLUSION: Catheter ablation of long-lasting persistent AF associated with acute AF termination achieves medium to long-term restoration and maintenance of sinus rhythm in 95% of patients. Arrhythmia recurrence in the majority of patients is AT.     

Catheter ablation is preferred over surgery for persistent atrial fibrillation

There are important limitations that can hinder outcomes of surgical ablation in nonparoxysmal patients with atrial fibrillation (AF), which is the typical AF population undergoing concomitant cardiac surgery for valve or ischemic heart disease. Incomplete lesions with recovered conduction or gaps as well as arrhythmias originating from areas not targeted by surgical ablation are commonly seen at the time of recurrence. Therefore, while it might be reasonable to perform AF surgery in this cohort, it is important to know these limitations and establish adequate postoperative rhythm monitoring to detect recurrences, which can be effectively addressed by catheter ablation.     

Tachycardia transition during ablation of persistent atrial fibrillation

Tachycardia Transition . Background: The “sequential ablation” strategy for persistent AF is aimed at progressive organization of AF until the rhythm converts to sinus rhythm or atrial tachycardia (AT). During ablation of an AT, apparently seamless transitions from one organized AT to another occur. The purpose of our study was to quantify the occurrence and the mechanism of this transition. Methods and Results: Twenty‐nine of 90 patients undergoing ablation for persistent AF had multiple AT during the procedure and constitute the study group. Thirty‐nine direct transitions from one AT to another during ablation were observed classified in four types: type I (79.4%), i.e., a direct transition of a faster to a slower tachycardia without significant intervening pause; type II (7.69%)—transition after intervening ectopy or longer pause; type III (10.26%)—A slower AT accelerated; type IV (2.56%)—alteration of activation sequence but with no change on CL. Conclusions: Transition to a second AT occurs frequently in the midst of ablation of AT in persistent AF patients. This transition occurs most commonly abruptly within the range of a single cycle length of the original AT. This is best explained by a continuation of AT that was “present” simultaneously with the pretransition tachycardia, being “entrained” (for a reentrant tachycardia) or “overdriven” for an automatic focal tachycardia. The presence of multiple tachycardia mechanisms active simultaneously would be consistent with the eclectic pathophysiology of persistent AF. (J Cardiovasc Electrophysiol, Vol. 22, pp. 506‐512 May 2011)     

经导管射频消融治疗老年阵发性心房颤动临床分析

目的评价射频消融治疗老年阵发性房颤患者的有效性和安全性。方法连续入选接受首次房颤射频消融术治疗的药物难治性阵发性房颤患者85例,按年龄大小分为老年人房颤组（≥60岁,45例）和非老年人房颤组（〈60岁,40例）,所有患者接受环肺静脉隔离术治疗。观察患者房颤的复发情况。结果通过（37.2±3.2）月的随访,85例患者中,共23例（27.1%）出现房颤复发,其中≥60岁与〈60岁年龄组在复发率上无显著性差异（12/45 vs 11/40,P=0.931）。85例患者中无1例出现消融相关严重并发症。结论经导管射频消融是治疗老年阵发性房颤的有效手段,其有效性及安全性与非老年人群并无临床差异。     

Catheter ablation of atrial fibrillation

Following the advent of the surgical maze procedure, several catheter techniques have been developed to provide permanent prophylaxis against atrial fibrillation. These noninvasive techniques work by compartmentalizing the atria, by ablating the arrhythmogenic foci, or by isolating the atria from these foci. Although still at an early stage of development, preliminary results using focal ablation and circumferential ablation show extreme promise.     

Dual independent atrial tachycardias after ablation of chronic atrial fibrillation

We report the case of a 71-year-old man with two atrial tachycardias evolving simultaneously and independently in two dissociated regions after extensive ablation for chronic atrial fibrillation. One tachycardia was a focal tachycardia originating from the right inferior pulmonary vein and activating the posterior left atrium with a 2:1 conduction block, while the other tachycardia was an atrial flutter circulating around the tricuspid annulus, activating the right atrium and the anterior wall of the left atrium. These two atrial tachycardias were successfully ablated prior to restoration of sinus rhythm.     

Catheter ablation of regular atrial arrhythmia following surgical treatment of permanent atrial fibrillation

Ablation of Atrial Tachycardia after Antiatrial Fibrillation Surgery. INTRODUCTION: Surgical treatment of atrial fibrillation (AF) is gaining widespread acceptance. However, therapeutic modalities for secondary regular atrial tachycardia are still empiric. METHODS AND RESULTS: After linear atrial cooled-tip radiofrequency ablation (SICTRA) during cardio-surgical procedures to cure permanent AF, patients with regular atrial tachycardia were identified. Invasive electrophysiology including electroanatomic mapping was performed. Catheter ablation was directed to suppress atrial arrhythmia depending on activation mapping findings. Follow-up was performed after 3 months and then after every 6 months. Of 238 patients, 12 (5.0%) were identified with regular secondary arrhythmias (12 +/- 7 months after surgery) including 9 (3.8%) with persistent forms originating from the right atrium (RA) in six (66%) (isthmus-dependent macroreentry in 4, incisional macroreentry in 1, and RA ectopy in 1). All patients with RA origin of the tachycardia were successfully ablated. Two patients had left atrial (LA)-macroreentry circling around the mitral valve indicating insufficiency of the intraoperative ablation procedure: one patient was successfully ablated within the LA isthmus, in the other patient no complete conduction block could be induced. One patient had LA-macroreentry degenerating into AF, and ablation was not performed. During follow-up (9 +/- 4 months), no recurrences of atrial tachycardias were documented after successful ablation. CONCLUSIONS: Persistent regular "secondary" arrhythmia occurred in 3.8% (9/238) of patients after SICTRA to treat permanent AF. Predominantly (67%; 6/9), the arrhythmia was located in the RA mostly incorporating the RA-isthmus. Catheter ablation was highly effective for RA tachycardia (100%). In three cases (33%), LA-macroreentry was documented and catheter ablation was successful in only one patient (overall success 78%).     

持续性心房纤颤的辅助消融策略

心房纤颤（简称房颤）是一种临床上最常见的持续性心律失常,发病率高,危害大。近年来,房颤的非药物治疗取得了较快发展,其中肺静脉隔离（PVI）就是一种有效的治疗方法。这种方法对于阵发性房颤患者治愈率较高,而在持续性房颤和长时程房颤患者中疗效一般。本综述主要探讨针对持续性房颤患者的最新辅助消融策略及其机制,包括线性消融、复杂碎裂心房电位（CFAE）消融、神经节（丛）消融、主频率消融、转子消融和与房颤触发相关的其他解剖位点消融。     

Catheter ablation of atrial flutter due to amiodarone therapy for paroxysmal atrial fibrillation.

AIMS: Antiarrhythmic drug treatment for atrial fibrillation can cause atrial flutter-like arrhythmias. The aim of this study was to clarify the effect of catheter ablation of the tricuspid annulus-vena cava inferior isthmus on amiodarone-induced atrial flutter and to determine the incidence of atrial fibrillation after catheter ablation of amiodarone-induced atrial flutter in comparison to regular typical flutter. METHODS AND RESULTS: Among 92 consecutive patients with typical atrial flutter who underwent isthmus ablation 28 patients had atrial flutter without a history of previous atrial fibrillation (group I), 10 patients had atrial flutter following the initiation of amiodarone therapy for paroxysmal atrial fibrillation (group II) and 54 patients had atrial flutter and atrial fibrillation (group III). Atrial cycle length during atrial flutter in amiodarone-treated patients (group II) (277+/-24 ms) was significantly longer as compared to the cycle length of atrial flutter in group I (247+/-33 ms) and group III patients (235+/-28 ms). The rate of successful transient entrainment and overdrive stimulation to sinus rhythm was not different between patients with (60%) or without amiodarone therapy (group I: 71%, group III: 53%). Successful isthmus ablation with bidirectional conduction block eliminating right atrial flutter was achieved in 90% of amiodarone-treated patients and 93% of patients without amiodarone therapy. In the amiodarone-treated patient group atrial conduction times during pacing in sinus rhythm were significantly prolonged by 20-30% before and after ablation in all regions of the reentrant circuit. During a mean follow-up of 8+/-3 months post-ablation, atrial fibrillation recurred in two of 10 patients on continued amiodarone therapy after successful isthmus ablation. Thus, successful catheter ablation of atrial flutter due to amiodarone therapy was associated with a markedly lower recurrence rate of paroxysmal atrial fibrillation (20%) as compared to patients with atrial flutter plus preexisting paroxysmal atrial fibrillation (76%) and was similar to the outcome of patients with successful atrial flutter ablation without preexisting atrial fibrillation (25%). CONCLUSION: These data suggest that isthmus ablation with bidirectional block and continuation of amiodarone therapy is an effective therapy for the treatment of atrial flutter due to amiodarone therapy for paroxysmal atrial fibrillation.     

Early recurrences after atrial fibrillation ablation: prognostic value and effect of early reablation

Introduction: Early arrhythmia recurrences are common within the first month after atrial fibrillation (AF) ablation. The long-term consequences of these early recurrences (ER) are controversial. We investigated whether ER were predictive of late recurrences and the impact of early reablation on clinical outcome.
Methods: Three hundred two consecutive patients with paroxysmal or persistent AF were studied. Arrhythmia recurrence was defined as documented episode of AF or atrial tachycardia. Of 151 patients with ER, a subset of 61 patients had reablation within the first month following the index ablation (early reablation). In the remaining 90 patients, a repeat procedure was only performed for later arrhythmia recurrences occurring beyond 1 month. Patients were followed with clinical interview and ambulatory 24 hours monitoring.
Results: Patients with and without early reablation had similar baseline characteristics including echocardiographic parameters and type of AF. During a mean follow-up of 11 ± 11 months, 82 patients (91%) without early reablation experienced late clinical recurrences. In contrast, patients with early reablation had lower rate of clinical recurrences (51% vs 91%, P < 0.0001) and fewer additional procedures (36% vs 91%, P < 0.0001). However, the total number of procedures over the entire follow-up was greater in those patients with early reablation (2.5 ± 0.7 vs 2.2 ± 0.6, P = 0.02).
Conclusion: An overwhelming majority of patients with recurrences within the first month after ablation have late recurrences. An early reablation reduces the incidence of further recurrences. However, the overall number of procedures is higher in the medium-term follow-up. The optimal timing for the second procedure remains to be defined.     

Catheter ablation of chronic atrial fibrillation targeting the reinitiating triggers

Trigger Ablation in Chronic AF. Introduction : We assessed the mode of reinitiation of atrial fibrillation (AF) after cardioversion and the efficacy of ablating these foci of reinitiation in patients with chronic AF.
Methods and Results : Fifteen patients, 7 with structural heart disease, underwent mapping and catheter ablation of drug-resistant AF documented to he persistent for 5 ± 4 months. In all patients, cardioversion was followed by documentation of P on T atrial ectopy and early recurrence, which allowed mapping of the reinitiating trigger or the source of ectopy. Radiofrequency (RF) ablation was performed at pulmonary vein (PV) ostia using a target temperature of 50°C and a power limit of 30 to 40 W, with the endpoint being interruption of all local muscle conduction. A total of 32 arrhythmogenic PVs and 2 atrial foci (left septum and left appendage) were identified: 1, 2, and 3 or 4 PVs in 5, 3, and 6 patients. RF applications at the ostial perimeter resulted in progressively increasing delay, followed by abolition of PV potentials in 8, but potentials persisted in 6. A single ablation session was performed in 7 patients and 8 underwent two or three sessions because of recurrence of AF; ablation was directed at the same source due to recovery of local PV potential or at a different PV. No PV stenosis was noted either acutely or at repeated follow-up angiograms. Nine patients (60%) were in stable sinus rhythm without antiarrhythmic drugs at follow-up of 11 ± 8 months. Anticoagulants were interrupted in 7 patients.
Conclusion : PVs are the dominant triggers reinitiating chronic AF in this patient population. Elimination of PV potentials by ostial RF applications results in stable sinus rhythm in 60%. A larger group and longer follow-up are needed to investigate further the role of trigger ablation in curative therapy for chronic AF.     

三维标测系统指导下消融治疗阵发性房颤

目的探讨左心房消融治疗阵发性心房颤动(房颤)的可行性和临床疗效.方法对4例阵发性房颤患者采用非接触心内膜激动标测系统(EnSite3000-NavX)建立左心房、肺静脉的三维等时电势图和电解剖图,并在距离肺静脉口1～2 cm处于左房后壁描记两环(一环包括左上、下肺静脉,另一环包括右上、下肺静脉)、两线(一线为左房后顶部两环之间,另一线为左环至二尖瓣峡部连线)作为消融隔离线,于非X线下分别沿各线依次消融.结果4例患者房颤全部终止,术后6个月内均未复发房颤,无一例患者出现并发症,平均手术时间(151.3±23.2)min,平均X线曝光时间(22.0±6.8)min.结论非接触心内膜标测系统指导下的左房消融是治疗阵发性房颤的有效而安全的方法.     

Hybrid epicardial and endocardial ablation of persistent or permanent atrial fibrillation: a new approach for difficult cases

Background : Although percutaneous epicardial catheter ablation (PECA) has been used for the management of epicardial ventricular tachycardia, the use of PECA for atrial fibrillation (AF) has not yet been reported.
Objective: To evaluate the efficacy and feasibility of a hybrid PECA and endocardial ablation for AF.
Methods: We performed PECA for AF in five patients (48.6 ± 8.1 years old, all male, four redo ablation procedures of persistent AF with a risk of pulmonary vein (PV) stenosis, one de novo ablation of permanent [AF]) after an endocardial AF ablation guided by PV potentials and 3D mapping (NavX). Utilizing an open irrigation tip catheter, a left atrial (LA) linear ablation from the roof to the perimitral isthmus or localized ablation at the junction between the LA appendage and left-sided PVs or ligament of Marshall (LOM) was performed.
Results: PECA of AF was successful in all patients with an ablation time of <15 minutes. The left-sided PV potentials were eliminated by PECA in all patients. Bidirectional block of the perimitral line was achieved in two of two patients and a left inferior PV tachycardia with conduction block to the LA was observed during the ablation in the area of the LOM in one patient. A hemopericardium developed in one patient, but was controlled successfully. During 8.0 ± 6.3 months of follow-up, all patients have remained in sinus rhythm (four patients without antiarrhythmic drugs).
Conclusion: A hybrid PECA of AF is feasible and effective in patients with redo-AF ablation procedures and at risk for left-sided PV stenosis or who are resistant to endocardial linear ablation.     

Bi-focal atrial tachycardia mimicking atrial fibrillation: fusion and interference between two distinct tachycardias

Irregular tachycardias mimicking atrial fibrillation (AF) have previously been described. We report a case of a 60-year-old man with an antiarrhythmic drug-resistant atrial tachycardia (AT) mimicking AF. The tachycardia consisted of two distinct ATs with interference of one repetitive AT with another sustained AT. Radiofrequency (RF) ablation of two distinct right atrial foci eliminated the irregular tachycardia. Although catheter-based pulmonary vein isolation has become a popular therapeutic approach for patients with symptomatic AF, careful evaluation of the intracardiac recordings in the patients undergoing RF ablation for AF is important.     

A strategy of rapid cardioversion minimizes the significance of early recurrent atrial tachyarrhythmias after ablation for atrial fibrillation

A Strategy of Rapid Cardioversion. Background: The significance of early recurrent atrial tachyarrhythmias after atrial fibrillation (AF) ablation is unclear. Atrial remodeling driven by these tachyarrhythmias can result in electrical, contractile, and structural changes that may impair long‐term therapy success. Aggressive attempts to restore sinus rhythm in the temporal period of healing after ablation might improve outcomes. Methods: A total of 1,759 AF ablations were performed at Intermountain Medical Center or LDS Hospital. A total of 455 of those were among patients requiring repeat ablations. Patients were instructed to take their pulse daily and, if greater than 100 bpm or irregular, present the following business day fasting to the clinic for evaluation and cardioversion if AF or atrial flutter (AFL) were present. Results: Of the ablations performed, a total of 515 (29%, age: 65.6 ± 11.2 years, male: 57.9%) developed AF/AFL that required cardioverison. The majority of these arrhythmias first occurred in the initial 90 days (63.7%) postablation. During this period, 62.8% were on an antiarrhythmic drug (AAD). Only 25.1% were using an AAD at 3 months. The majority of ablations (75.6%) who experienced AF/AFL within the first 90 days after ablation were in sinus rhythm with no AAD at 1 year. Further, 48% of those with the first recurrence from 90 to 180 days were in sinus rhythm with no AAD at 1 year. Conclusions: The time at which the first recurrence of AF/AFL occurs impacts long‐term outcomes. An aggressive strategy of rapid cardioversion postablation reduces the significance of recurrent AF/AFL during the first 6 months . (J Cardiovasc Electrophysiol, Vol. 22, pp. 761‐766, July 2011)