Right Atrial Compartmentalization Using Radiofrequency Catheter Ablation for Management of Patients with Refractory Atrial Fibrillation

INTRODUCTION: Atrial fibrillation (AF) is often refractory to antiarrhythmic drugs, and patients who are intolerant of AF may require the maze operation for cure. As a less invasive alternative, a catheter-based, right atrial compartmentalization procedure was evaluated. METHODS AND RESULTS: Twelve patients with AF refractory to Class I and III antiarrhythmic drugs were studied. Four linear right atrial radiofrequency ablations were performed, from superior to inferior vena cava in the posterior wall and interatrial septum, anteriorly from the superior vena cava to the tricuspid annulus through the appendage, and across the tricuspid valve-inferior vena cava isthmus. The radiofrequency catheter was dragged along each line three to four times, until the atrial electrogram amplitude decreased by 75% and there was bidirectional conduction block in the tricuspid valve-inferior vena cava isthmus. One complication occurred: sinus node dysfunction requiring a pacemaker. Eight patients were discharged from the hospital on no antiarrhythmic drugs, and four were discharged on previously ineffective antiarrhythmic drugs. Total duration of follow-up was 21.3 +/- 11.2 months. Four patients discharged on previously ineffective antiarrhythmic drugs had no recurrence of AF. One patient discharged off antiarrhythmic drugs had no recurrence of AF. Seven patients discharged off antiarrhythmic drugs had recurrent AF by 12.6 +/- 13.0 months (median 6, range 1 to 39); 3 of these 7 responded to previously ineffective antiarrhythmic drugs without further AF and 4 did not. Thus, 8 of 12 patients (67%) had suppression of AF after ablation on previously ineffective medication or no medication. CONCLUSION: Right atrial compartmentalization may alter the substrate for AF, thus improving the efficacy of previously ineffective antiarrhythmic drugs. Because it is relatively safe, it may be a reasonable adjunctive intervention to maintain sinus rhythm in patients with drug-refractory AF.     

Radiofrequency Modification of the Atrioventricular Node in Patients with Chronic Atrial Fibrillation:

RF Modification of AVN in AF. Introduction : We compared, in a prospective and randomized fashion with a cross-over design, the anterior and posterior approaches to radiofrequency (RF) modification of the AV node in patients with chronic atrial fibrillation.
Methods and Results : Thirty-three patients were randomized to receive first an anterior (group I) or posterior (group II) approach for RF modification of AV nodal conduction. Patients who did not fill the endpoint ventricular rate (< 90 beats/min) were crossed over to the alternative approach. After the anterior approach in group I patients, mean ventricular rate was significantly lower than in group II patients after the posterior approach (79.6 ± 18.8 beats/min vs 110.8 ± 16.2 beats/min, P < 0.001). In group I, 14 (82%) of 17 patients fulfilled the endpoint, 1 (6%) had complete AV block, and 2 (12%) were crossed over to the posterior approach fulfilling the endpoint. In group II, 4 (25%) of 16 patients fulfilled the endpoint. No transient or permanent high-degree AV block was observed. Among the 12 patients who were crossed over to the anterior approach, 8 fulfilled the endpoint, whereas 4 had permanent high-degree AV block. RF ablation carried out only in the anterior region was safer than a stepwise approach (6% vs 33% incidence of AV block), even though the difference did not reach statistical significance (P = 0.09).
Conclusion : Posterior AV nodal modification is less effective but safer than anterior AV nodal modification. However, to reduce the incidence of AV block, the anterior approach is preferable to a stepwise approach from the posterior to the anterior zone.     

Right Atrial Mapping and Linear Ablation for Paroxysmal Atrial Fibrillation

Objective: Catheter ablation techniques to cure atrial fibrillation (AF) are under investigation. This study evaluates a mapping-based, individualized approach to right atrial (RA) linear ablation in patients with paroxysmal AF. Methods: In this prospective observational study, 29 patients with recurrent symptomatic AF refractory to medical therapy, underwent linear ablation between May 1998 and December 1999. Inclusion criteria were symptomatic paroxysmal AF, failure of at least 2 antiarrhythmic medications, and informed consent. Radiofrequency ablation was performed in the RA using a 3.3 French multielectrode catheter, ablating through sequential electrodes to establish linear lesions. Lesions were delivered during sustained AF, guided by an empiric mapping scheme, targeting arrhythmogenic areas noted during electrophysiologic testing in sinus rhythm and areas of most disorganization during AF. Reinduction of AF was attempted at the end of successful ablation. Results: The mean age was 58 years. There were 15 male and 14 female patients. Sustained AF was inducible in all patients at electrophysiology study. Acute success was achieved in 24 patients (83%). Long term success (maintaining sinus rhythm off antiarrhythmic medications) was seen in 23 (79%) over a mean follow-up of 19.7 months. Ablation lines varied from patient to patient. There were no complications. Conclusions: Individualized linear ablation in the RA using a multielectrode catheter system can produce effective suppression of paroxysmal AF. Ablation during AF, and testing to reinduce AF at the end of the procedure, make this study unique.     

Stiff Left Atrial Syndrome: A Complication Undergoing Radiofrequency Catheter Ablation for Atrial Fibrillation

Radiofrequency catheter ablation for atrial fibrillation is an effective approach for treating atrial fibrillation. Its complications have attracted much attention, of which the stiff left atrial syndrome is a recently discovered complication that has not been completely understood. This study aims to investigate the concept, pathologic basis, clinical characteristics, predictors, and treatment protocols of the stiff left atrial syndrome after radiofrequency ablation for atrial fibrillation.     

Feasibility of a Left Atrial Electrical Disconnection Procedure for Atrial Fibrillation Using Transcatheter Radiofrequency Ablation

INTRODUCTION: An effective, catheter-based treatment for persistent atrial fibrillation (AF) remains elusive. This study assessed the feasibility of transcatheter left atrial (LA) electrical disconnection and its effect on AF inducibility. METHOD AND RESULTS: Thirteen anesthetized swine underwent noncontact mapping of the right atrium (RA) during coronary sinus (CS) pacing. Sites of earliest RA activation were identified using isopotential maps. An ablation catheter was navigated to these sites and a cluster of radiofrequency (RF) lesions applied until earliest activation shifted to a new site. The procedure was repeated until the atria were electrically disconnected. AF induction was attempted before and after ablation. Earliest RA activation was the CS os during proximal CS pacing and Bachmann's bundle during distal CS pacing. These two sites were successfully ablated in all 13 animals. Earliest activation then shifted to the fossa ovalis. RF energy was applied at a median of 2.5 sites (range 1 to 5) around the fossa, then at sites in the triangle of Koch, septum, cavotricuspid isthmus, and posterior wall. Atrial electrical disconnection was achieved in 10 of 13 animals (5 LA electrical disconnection, 3 RA electrical disconnection, 2 biatrial electrical disconnection with complete heart block). After atrial electrical disconnection, the LA became electrically silent. Before ablation, AF was inducible in every animal. After atrial electrical disconnection, AF was inducible in 3 of 10 animals. CONCLUSION: Atrial electrical disconnection is feasible using noncontact mapping and RF ablation. Successful electrical disconnection of the atria reduces AF inducibility. This approach is worthy of further evaluation as a management strategy for persistent AF, combined with device therapies.     

心腔内超声在心房颤动射频消融中的应用

心房颤动的射频消融是心血管领域热门课题,传统的X线影像下的心房颤动射频消融尽管取得很大进展,但仍然有许多亟待解决的问题。心腔内超声技术的诞生和发展极大克服了放射影像下心房颤动射频消融的不足,拓展了心房颤动射频消融的空间。     

Critical Atrial Site for Ablation of Pacing-Induced Atrial Fibrillation in the Normal Dog Heart

Site for Ablation of AF in Dogs. Introduction: Radiofrequency catheter ablation (RFA) has been used recently to treat atrial fibrillation (AF). The purpose of this study was to investigate a new approach to preventing AF by RFA.
Methods and Results: In open chest, anesthetized dogs, AF (lasting > 30 sec) was induced after burst stimulation, and electrophysiologic parameters were recorded before and after RFA. In group 1 (9 dogs) we performed selective and combined slow and fast pathway RFA, whereas in group 2(11 dogs) RFA was applied as a linear lesion at the mid-atrial septum between the inferior vena cava and the fossa ovalis. After ablation, the Wenckebach cycle length was significantly prolonged only in group 1 (194 ± 23 vs 282 ± 35 msec, P = 0.002). whereas the interval between the stimulus (S) artifact applied at the high right atrium to the His hundle (H) (SH interval) prolonged to the same extent in both groups (162 ± 14 vs 146 ± 45 msec. P = NS); group 1 due to an A-H prolongation whereas in group 2 it was due to an intra-atrial conduction delay. In group 1 AF still remained inducible, although with a longer mean R-R interval (215 ± 16 vs 433 ± 88 msec, P < 0.05). No instance of complete AV block developed. In group 2, sustained AF was noninducible in 10 dogs and its duration was markedly shorter in the remaining one (8 sec). Gross anatomy and histology did not reveal any damage inside of Koch's triangle, and particularly to the compact AV node.
Conclusion: These findings suggest that RFA at the mid-atrial septum prevents AF in the normal dog heart. This approach might also be successful in those clinical settings in which the atrial septum plays a critical role in the maintenance of sustained AF.     

Advances in Catheter Ablation: Atrial Fibrillation Ablation in Patients With Mitral Mechanical Prosthetic Valve

Atrial fibrillation (AF) is common in patients with mitral valve replacement (MVR). Treatment of AF in these subjects is challenging, as the arrhythmia is often refractory to antiarrhythmic drug therapy. Radiofrequency catheter ablation (RFCA) is usually avoided or delayed in patients with MVR due to the higher perceived risks and difficulty of left atrial catheter manipulation in the presence of a mechanical valve. Over the last few years, several investigators have reported the feasibility and safety of RFCA of AF in patients with MVR. Five case-control studies have evaluated the feasibility and safety of RFCA of AF or perimitral flutter (PMFL) in patients with MVR. Overall, a total of 178 patients with MVR have been included (21 undergoing ablation of only PMFL), and have been compared with a matched control group of 285 patients. Total procedural duration (weigthed mean difference [WMD] = +24.5 min, 95% confidence interval [CI] +10.2 min to +38.8 min, P = 0.001), and fluoroscopy time (WMD = +13.5 min, 95% CI +3.7 min to +23.4 min, P = 0.007) were longer in the MVR group. After a mean follow-up of 11.5 ± 8.6 months, 64 (36%) patients in the MVR group experienced recurrence of AF/PMFL, as compared to 73 (26%) patients in the control group, accounting for a trend toward an increased rate of recurrences in patients with MVR (odds ratio [OR] = 1.66, 95% CI 0.99 to 2.78, P = 0.053). Periprocedural complications occurred in 10 (5.6%) patients in the MVR group, and in 8 (2.8%) patients in the control group (OR = 2.01, 95% CI 0.56 to 7.15, P = 0.28). In conclusion, a quantitative analysis of the available evidence supports a trend toward a worse arrhythmia-free survival and a higher absolute rate of periprocedural complications in patients with MVR undergoing RFCA of AF or PMFL, as compared to a matched control group without mitral valve disease. These data would encourage the adoption of RFCA of AF in MVR patients mostly by more experienced Institutions.     

心腔内三维超声辅助下经导管射频消融治疗心房颤动伴造影剂不相容患者的临床分析

目的:探讨心腔内三维超声辅助下经导管射频消融治疗心房颤动伴造影剂不相容患者的安全性及临床疗效。方法:选择2015年1月至2017年1月期间中国医学科学院阜外医院收治的16例心房颤动伴造影剂不相容的患者。患者均未行左心房、肺静脉CT和造影,在心腔内三维超声辅助下建立左心房及肺静脉三维模型,并指导穿刺房间隔和消融导管在心脏内的操作。结果:15例患者顺利完成心房颤动射频消融,平均手术时间(96.0±14.3)min,透视时间(6.1±1.2)min,X线透视剂量(115.8±49.3)mGy,未发生心脏压塞、脑栓塞、左心房-食道瘘、肺静脉狭窄及动脉瘤等并发症及死亡。1年随访结果显示,9例患者维持窦性心律,其中阵发性心房颤动7例,持续性心房颤动2例。结论:对于心房颤动伴造影剂不相容的患者,心腔内三维超声可以替代经食道超声心动图,避免左心房造影及增强CT检查;心腔内三维超声不延长手术时间,显著减少X线曝光时间及剂量,可避免穿刺房间隔的并发症,提高穿刺准确性。     

微创外科消融治疗心房颤动的进展

心房颤动是临床中最常见的心律失常之一,外科治疗心房颤动已有近30年的历史。近10年来,微创外科消融手术作为一种创伤小的、治愈率高的治疗手段在治疗心房颤动方面取得了长足的进展。心房线性消融和自主神经节消融的具体手术策略因尚无统一的标准术式而倍受关注;微创外科用于治疗心房颤动,在应用中也暴露了其自身的缺点和不足,也正因如此,近年来一些新的技术方法和创新理念被融入微创外科消融手术中来,并日渐加以改进和完善。相信伴随着手术方式的改良、手术设备的改进以及理念的创新,微创消融手术治疗心房颤动会不断拓展其手术适应证并会被更多的人接受。     

Surgical Ablation of Atrial Fibrillation

The Cox-maze procedure for the restoration of normal sinus rhythm, initially developed by Dr. James Cox, underwent several iterations over the years. The main concept consists of creating a series of transmural lesions in the right and left atria that disrupt re-entrant circuits responsible for propagating the abnormal atrial fibrillation rhythm. The left atrial appendage is excluded as a component of the Maze procedure. For the first three iterations of the Cox- maze procedure, these lesions were performed using a surgical cut-and-sew approach that ensured transmurality. The Cox-Maze IV is the most currently accepted iteration. It achieves the same lesion set of the Cox- maze III but uses alternative energy sources to create the transmural lesions, potentially in a minimally invasive approach on the beating heart. High-frequency ultrasound, microwave, and laser energy have all been used with varying success in the past.Today, bipolar radiofrequency heat or cryotherapy cooling are the most accepted sources for creating linear lesions with consistent safety and transmurality. The robust and reliable nature of these energy delivery methods has yielded a success rate reaching 90% freedom from atrial fibrillation at 12 months. Such approaches offer a significant long-term advantage over catheter-based ablation, especially in patients having longstanding, persistent atrial fibrillation with characteristics such as dilated left atrial dimensions, poor ejection fraction, and failed catheter ablation. Based on these improved results, there currently is significant interest in developing a hybrid ablation strategy that incorporates the superior transmural robust lesions of surgical ablation, the reliable stroke prevention potential of epicardial left atrial appendage exclusion, and sophisticated mapping and confirmatory catheter-based ablation technology. Such a minimally invasive hybrid strategy for ablation may lead to the development of multidisciplinary “Afib teams” to obtain optimal long-term sinus rhythm control. This article provides an overview of current surgical strategies for patients with atrial fibrillation and addresses the two main goals in its management.     

点消融治疗起源于肺静脉的局灶性心房颤动(附一例报告)

报道 1例成功消融的局灶性心房颤动 (简称房颤 )。男性、5 3岁 ,有阵发性心悸病史 3年。诊断为特发性房颤。多次 2 4 h心电图发现有频发房性早搏 (简称房早 )及反复发作的短暂房颤 ,房颤由房早发动 ,自动终止。放置 6F多极导管电极于右室、His束及冠状静脉窦 (CS) ,Halo电极置于右房。普通温控 4 mm可操纵大头消融电极经房间隔穿刺鞘管送入左房。在左上肺静脉入口 10 mm内标测到最提前的电位 ,比体表心电图房早的 P 波明显提前 60 ms。采用温控法 (5 5～ 60℃ )放电 2次 ,消融成功。随诊 3个月 ,无并发症 ;未服用抗心律失常药物 ,无房颤发作。结论 :点消融是治疗起源于肺静脉房颤的安全有效方法。     

Inducibility of Atrial Fibrillation Before and After Radiofrequency Catheter Ablation of Accessory Atrioventricular Connections

Inducibility of Atrial Fibrillation. Introduction: The purpose of this study was to evaluate the inducihility of atrial fibrillation in patients with an accessory atriovcentricular connection (AAVC) and to determine if the inducibility of atrial fibrillation is altered after successfulradiofrequency catheter ablation of the AAVC.
Methods and Results: Thirty-seven patients with an AAVC and 36 control patients wereprospectively evaluated using a standardized atrial pacing protocol. The high right atrium waspaced using a 25-beat drive train, 1.5-second intertrain pause, 10-mA pulse amplitude, and 2-msec pulse duration at cycle lengths of 250 to 100 msec, in 10-msec decrements. Pacing wasperformed twice at each cycle length. Thirty patients with an AAVC underwent repeat atrialoverdrive pacing after successful radiofrequency ablation of the AAVC. Atrial fibrillation wasinduced in 26 (70%) patients with an AAVC and 22 (61 %) controls (P = NS). Atrial flutter wasinduced in 26 (70%) patients with an AAVC and 22 (61%) controls (P = NS). The cumulativepercentage of patients with atrial fibrillation/flutter induced at each pacing cycle length was thesame in each group. There was no difference in the duration of atrial fibrillation/flutterbetween control patients and patients with an AAVC. Among the 30 patients who underwentrepeat atrial overdrive pacing after radiofrequency ablation of an AAVC, there was no difference in the inducibility or duration of atrial fibrillation/atrial flutter after ablation compared tobaseline.
Conclusion: These findings indicate that the vulnerability of the atrium to fibrillate inresponse to atrial pacing is independent of the presence of an AAVC.     

应用心腔内超声指导局灶性心房颤动的射频消融

探讨在心腔内超声 (ICE)导引下对局灶性心房颤动 (简称房颤 )行射频消融治疗的可行性和安全性。选择 4例阵发性房颤而无器质性心脏病的患者 ,在 ICE指导下根据电生理检查的定位结果分别在左房的左上肺静脉、右上肺静脉及右房终末嵴上部进行射频消融。消融能量为 3 0 W,消融温度为 60℃ ,放电时间 87～ 12 0 s。结果 :右房内超声均可在单幅影像下动态显示卵圆窝、主动脉、左房 ,穿刺房间隔时可避免误穿主动脉或穿刺针过深穿破左房。左房内超声可显示肺静脉及其分支的内部结构以及导管与内壁的贴靠紧密与稳定程度。 1例术中房颤终止 ,术后 1天复发 ;2例消融后房早消失 ,随访一周无房颤复发 ;1例术中消融后可诱发房颤但随访半年无房颤发作。结论 :在ICE导引下对局灶性房颤进行射频消融 ,能增加安全性和可靠性 ,是一种较有前途的方法。     

Comparison of Radiofrequency and Cryoballoon Pulmonary Vein Ablation for the Early and Late Recurrence of Atrial Fibrillation

Objective Early recurrence (ER) after pulmonary vein isolation (PVI) for atrial fibrillation (AF) is expected to resolve within the recommended 3-month blanking period, irrespective of the ablation device used. To compare the occurrence and relationship of AF within the blanking period and subsequent late recurrence (LR) with radiofrequency (RF) and cryoballoon (CB) ablation. Methods A retrospective analysis of 294 patients (mean age=62±9, 70.0% male) undergoing PVI for drug-refractory paroxysmal AF was done. After categorizing the patients into the RF group (n=152) and the CB group (n=142), a group-wise comparison was done to investigate the impact of ER on LR throughout a 2-year follow-up. Results The groups were similar regarding the occurrence of ER (RF=22.4%, CB=24.6%, p=0.62), while LR was significantly higher in the RF group (p=0.003). ER was associated with LR in the RF group (p<0.01) but not in the CB group (p=0.08), while a significant independent association with an increased LR risk was observed [hazard ratio (HR) 6.12; 95% confidence interval (CI) 3.56-10.51, p<0.01]. RF ablation also significantly increased the risk of LR (HR=2.93; 95% CI=1.64-5.23, p<0.01). Conclusion A recurrence of atrial arrhythmia is more frequent with RF-PVI than with CB-PVI for patients with paroxysmal AF. ER and RF-ablation are strong predictors for LR after the 3-month blanking period.     

Comparison of Cryoballoon and Radiofrequency Ablation of Pulmonary Veins in 40 Patients with Paroxysmal Atrial Fibrillation: A Case‐Control Study

Introduction: Ablation of pulmonary veins (PV) is an established therapeutic option for patients with symptomatic drug‐refractory paroxysmal atrial fibrillation (AF). Radiofrequency (RF) is currently the most widespread energy source for PV ablation. Cryothermal energy applied with a cryoballoon technique as an alternative has recently evolved. Methods and Results: In a case‐control setting, we compared 20 patients with paroxysmal AF who underwent their first PV ablation with the cryoballoon technique to 20 matched patients with conventional RF ablation. In the case of persistent electrical potentials after cryoballoon ablation, it was combined with ablation with a conventional cryocatheter. All patients performed daily event recording for 3 months after ablation procedure. Ablation parameters and success rate after 3 and 6 months were compared. In the cryoballoon group, the overall success rate was 55% (50% in the cryoballoon only group [14 patients] and 66% in the combination group [6 patients]), as opposed to the RF group with 45%. AF episode burden was lower after cryoballoon ablation. There was no significant difference between cryoballoon and RF ablation regarding procedure parameters. In the cryoballoon group, 3 phrenic nerve palsies occurred using the 23 mm balloon that resolved spontaneously. Conclusion: PV ablation with the cryoballoon technique is feasible and seems to have a similar success rate in comparison to RF ablation. Procedure‐ and fluoroscopy duration are not longer than in conventional RF ablation.     

Radiofrequency Catheter Ablation in Unusual Mechanisms of Atrial Fibrillation:

RF Catheter Ablation in AF. Introduction: The purpose of this study was to test the feasibility of radiofrequency (RF) catheter ablation of localized mechanisms of atrial fibrillation (AF).
Methods and Results: Three patients underwent RF catheter ablation for drug-resistant atrial arrhythmias. The first two patients had either incessant atrial tachycardia or AF. In the first patient, the KCG pattern of AF was mimicked by a very rapid atrial focus, whereas in the second patient, AF was due to true degeneration of the atrial activity triggered by atrial tachycardia. In both patients, the ablation of atrial focus led to the clinical disappearance of AF. The third patient had frequent episodes of AF, which lasted several days or weeks, and two documented episodes of atrial flutter. Mapping during AF showed an irregular atrial rhythm in the atrial septum, particularly in the region surrounding the coronary sinus, whereas the entire lateral right atrial free wall exhibited a constantly organized rhythm. RF energy was applied between the tricuspid ring and both the inferior vena cava and the coronary sinus, resulting in inability to reinduceatrial flutter or sustained AF. A 6-month follow-up in this patient showed the disappearance of prolonged episodes of AF.
Conclusion: The observations indicate that AF may be linked to "focal" mechanisms that can be treated by RF catheter ablation.