阵发性心房颤动的射频导管消融大静脉电隔离治疗

目的报道阵发性心房颤动(房颤)的射频导管消融电隔离肺静脉和腔静脉的疗效。方法阵发性房颤患者36例,年龄(42.5±13.2)岁。经1次房间隔穿刺放置环状标测电极导管(Lasso导管)和冷盐水灌注消融导管,在Lasso导管的指导下,采用全肺静脉或上腔静脉与靶静脉节段性电隔离相结合的方法对肺静脉和腔静脉行标测和电隔离治疗。窦性心律时最早激动的肺静脉和腔静脉电位处和/或心房起搏时最短的心房和静脉电位间期处为靶点行消融。结果36例阵发性房颤患者均接受一次电隔离治疗,共电隔离大静脉115根,其中左上肺静脉34根,左下肺静脉22根,右上肺静脉30根,右下肺静脉17根,上腔静脉12根,即刻电隔离成功率为95.6%,术中并发症发生率2.78%。随访3~22个月,成功率(无房颤发作或房颤发作明显减少)为75.0%。结论射频导管消融电隔离肺静脉或腔静脉与心房间的电活动连接,可有效预防房颤的复发。治疗的关键是消融靶点的标测和确定。     

环状电极标测指导射频消融治疗肺静脉起源的阵发性房颤

背景　常规方法标测射频消融治疗局灶性房颤常导致较长的手术时间及较低的成功率。环状电极标测指导射频消融能够克服这些缺点。目的　评价在 10极环状电极标测指导下射频消融电隔离肺静脉治疗阵发性房颤的可行性和有效性。方法　本组研究包括 16例抗心律失常药物治疗无效的阵发性房颤患者 [男性 11例 ,女性 5例 ,平均年龄 (5 1± 14 5 )岁 ]。 10极的环状标测电极在窦性心律或者冠状窦远端 (CSd)起搏的情况下标测肺静脉 ,确定房性早搏发生的起源 ;一旦确定靶肺静脉 ,肺静脉电位的分布及其激动顺序进行评价 ,射频消融在肺静脉口最早激动处进行。消融终点设定为 :①肺静脉电位消失 ;②肺静脉电位与心房电位无关 ;③房早消失。结果　本组研究总共消融了 36条肺静脉 ,包括 16条左上肺静脉 ,12条右上肺静脉 ,7条左下肺静脉 ,1条右下肺静脉。有 2例消融了 1条肺静脉 ;8例消融了 2条肺静脉 ;5例消融了 3条肺静脉 ;消融 4条肺静脉者 1例。手术时间以及X线曝光时间分别为 (186 7± 6 3 8)min及 (5 1 5± 15 0 )min。在随访的 1～ 12月 ,11例 (6 8 7% )在未服抗心律失常药没有房颤发作 ,其中 2例为再次手术 ,有效者 3例 (18 7% ) ,2例未成功 (12 6 % )。初次术后有 2例发作房早 ,其中 1例服用胺碘酮 ,另外 1     

电生理标测指导下肺静脉电隔离术治疗慢性心房颤动

目的探讨电生理标测指导下的肺静脉电隔离术治疗慢性心房颤动(房颤)的可行性.方法 20例慢性房颤患者,男14例,女6例,年龄56～72岁(平均68±7岁);房颤病史1～9年(平均3±7年),经过至少一次的体外同步心脏电复律,房颤均在30 min内复发.电生理标测指导下的肺静脉隔离方法为(1)最早激动点指导下消融.肺静脉内的Basket导管记录的心房电活动显示节律较规整,激动顺序一致.(2)房颤长间歇(连续记录的最长心房电活动间期>300 ms)指导下消融.肺静脉内电位节律紊乱,激动顺序不一致,房颤长间歇后的第一次心脏搏动的最早激动部位为消融靶点.(3)3型房颤波指导下的消融.房颤频率快,肺静脉内Basket导管记录的电活动激动顺序紊乱,部分电极记录的心内电图等电位线消失而不能确定孤立的心房电活动(3型房颤),此部位作为消融靶点.在房颤过程中完成4支肺静脉电隔离后,房颤不能自发终止者应用体外同步电复律.重新将Basket 导管放入肺静脉,仍记录到肺静脉电位者将在窦性心律下完成电隔离.结果 (1)临床结果所有患者在肺静脉隔离后成功转复为窦性心律,其中1例患者自行转复为窦性心律,2例患者转为心房扑动,经右心房峡部消融后转为窦性心律,余患者经体外同步电复律转为窦性心律.随访3～19个月(平均8±9个月),维持窦性心律者9例(45%),11例(55%)患者复发,无有症状性的肺静脉狭窄.(2)消融结果20例患者的76 支肺静脉电隔离被完成.68支(89.5%)肺静脉电隔离在房颤中完成,其中的23支肺静脉在窦性心律时记录到肺静脉电位,继续在窦性心律下消融,均完成电隔离;8支(10.5%)在房颤时未能完成电隔离的肺静脉,在窦性心律下成功隔离.手术时间4.2～7.6 h(平均5.3±3.7 h),平均X线曝光时间2.7 h,无栓塞、心包填塞及肺静脉狭窄等严重并发症.结论 (1)电生理指导下的肺静脉隔离治疗慢性房颤仍能达到较高的临床成功率.(2)电生理指导下的肺静脉隔离是安全可行的.(3)房颤过程中隔离的肺静脉仍需要在窦性心律下被重新证实.(4)在房颤过程中较难隔离的肺静脉可在转复窦性心律后进行隔离.     

射频消融肺静脉电隔离术治疗阵发性房颤20例

目的观察电生理标测指导下肺静脉电隔离术治疗阵发性房颤的临床疗效.方法阵发性房颤患者20例,环状电极指示下对肺静脉行射频消融电隔离术.结果20例患者共接受心脏大静脉电隔离治疗28次(6例进行了第2次,1例进行了第3次),隔离静脉68根,肺静脉62根,上腔静脉6根,在房颤心律下消融58根,62根肺静脉中54根达到消触终点.平均操作时间和X线透视时间分别为(120±18)min和(32±9)min.平均随访(5.0±2.3)个月,示13例无房颤发作、2例房颤发作明显减少,总有效率达75%.结论肺静脉电隔离术治疗阵发性房颤具有较好临床疗效.     

肺静脉电隔离治疗持续性心房颤动方法学及效果评价

目的对肺静脉电隔离治疗持续性心房颤动(房颤)的方法学及效果进行评价。方法14例持续性房颤患者,房颤病史6个月～20年,房颤持续时间1周～4个月,左心房直径37～47 mm平均(40．8±26．0)mm,左心室射血分数0．26-0．68平均0．55±0．11。术前抗凝治疗2～3周。术中常规放置冠状静脉窦导管及右心室起搏导管。房间隔穿刺成功后送入肺静脉环状标测电极导管(Lasso电极导管)及盐水灌注消融导管,预设功率30 W,温度50℃,于肺静脉口依次对4根肺静脉进行隔离。电复律恢复窦性心律后,再将Lasso电极导管依次送入各肺静脉口部标测,在残存肺静脉电位(PVP)的部位继续消融至心房与肺静脉完全电隔离。结果共对54根肺静脉进行电隔离,左上肺静脉14根,左下肺静脉13根,右上肺静脉14根,右下肺静脉13根,电隔离成功后PVP均完全消失,即刻成功率100％,平均放电时间(2 972±843)s。1例出现心脏压塞。随访12-18个月,无房颤复发5例(36％);症状明显减轻、房颤发作频率及持续时间明显减少4例(28％);症状无改善,房颤仍持续发作5例(36％),总有效率64％。结论肺静脉电隔离对持续性房颤治疗有效,其方法学可行但存在一定局限性。     

阵发性心房颤动患者肺静脉与心房电连接特征的临床研究

目的 总结阵发性心房颤动(房颤)患者肺静脉的电生理标测和导管射频消融电隔离的结果，评估中国人肺静脉与心房的电连接类型和特点。方法 顽固性阵发性房颤患者43例，在环状标测电极指导下行肺静脉电位(PVP)记录和分析，并对能标测到PVP的肺静脉进行开口部的点或段的消融电隔离治疗。根据窦性心律和心房起搏下的肺静脉内环形标测电报导管标测到的PVP的激动顺序，以及有效放电对PVP的影响，分析和总结肺静脉与心房之间的电连接特点。结果 共标调和域电隔离肺静脉100根，其中呈单束状电连接35根(35％)，双束状电连接48根(48％)，多束状电连接11根(11％)，环状电连接3根，无电连接3根。结论 根据环状电报标测到的PVP激动顺序和对放电的反应，提示肺静脉与心房之间电连接的类型多为单束状和双束状(83％)，说明对于大多数肺静脉不必进行环状消融，而只需在肺静脉与心房连接处进行点状或节段性消融即可达到完全电隔离的效果。     

射频消融双上肺静脉口治疗心房颤动一例

采用射频消融电学隔离双上肺静脉口成功治疗心房颤动 (简称房颤 ) 1例。电学隔离法有如下几个优点 :①以环型肺静脉 (PV)标测电极导管精确地显示整个环型管壁的电活动及靶点位置 ,引导靶肺静脉的电学隔离。②消融终点不仅要求自发或诱发的房性早搏 /房颤消失 ,而且要求消除靶肺静脉口所有的PV电位 ,它在窦性心律下或起搏冠状窦远端下即可消融和判断终点 (靶肺静脉电学隔离 ) ,不仅节省了大量的时间 ,而且提高了手术的成功率。③在肺静脉开口部 (或近端 )消融 ,较少出现PV狭窄     

经球囊超声消融肺静脉治疗阵发性心房颤动的初步结果

报道采用经球囊超声消融系统进行肺静脉电学隔离治疗 4例阵发性心房颤动 (简称房颤 )的初步结果。消融部位为双上肺静脉和左下肺静脉。总计对 11根肺静脉进行了超声消融 ,其中 9根达到消融终点———肺静脉电位消失。电学隔离一根肺静脉需平均进行 3.3(1～ 6 )次超声消融。消融后的肺静脉造影未见急性肺静脉狭窄。X线透视时间平均 32 (19～ 40 )min ,操作时间平均 2 .4(1.9～ 3.0 )h。术后平均随访 2 2 (19～ 2 5 )天 ,仅 1例 (2 5 % )患者房颤未再发作。结论 :采用经球囊超声系统进行多肺静脉的电学隔离方法简便 ,但效果仍有待进一步评价     

在心房颤动发作时行肺静脉隔离治疗

目的　探讨在心房颤动 (房颤 )发作时 (包括部分持续性房颤 )进行肺静脉节段性电隔离的方法 ,评价其安全性及有效性。方法　选择 5例持续半年以内的房颤病例及 4例发作频繁的房颤病例 ,在房颤发作时行肺静脉电隔离。通过一次性房间隔穿刺送入标测及消融导管 ,行左房或肺静脉选择性造影 ,显示肺静脉后 ,标测肺静脉电位活动 ,并行节段性隔离。结果　 9例患者共 2 9条肺静脉 ,肺静脉电位特征明确 ,在肺静脉环状电极标测到较左房电位振幅高尖 ,频率更快的肺静脉电位。选择最高尖处或频率最快处电位开始节段性消融。肺静脉电位 10 0 %消失 ,无并发症发生。 7例手术中或术后转为窦性心律。 2例电复律恢复窦性心律。结论　房颤发作时行肺静脉节段性电隔离方法安全、有效     

射频导管消融进行心房-肺和/或上腔静脉电隔离治疗阵发性心房颤动

目的　总结射频导管消融行心房 肺和 /或上腔静脉 (大静脉 )电隔离治疗阵发性心房颤动 (房颤 )的疗效。方法　选择发作频繁、症状明显 ,药物治疗无效的 10 0例阵发性房颤患者 ,男性 72例、女性 2 8例 ,年龄 2 7～ 75(54± 10 )岁 ,均无瓣膜病等器质性心脏病依据。在环状标测电极导管 (Lasso导管 )指导下行心内电生理标测和心房 靶大静脉 (指术中标测证实为房颤相关的肺静脉或上腔静脉 )电隔离和 /或经验性大静脉电隔离 (指术中无心律失常发作而不能明确房颤相关大静脉 ,主要对双上肺静脉和左下肺静脉进行电隔离 )。结果　 10 0例患者共接受电隔离治疗 12 0次。行单纯心房 靶大静脉电隔离 2 2例 ,经验性大静脉电隔离 78例 ,共电隔离大静脉 2 68根 ,其中肺静脉 2 44根 ,上腔静脉 2 4根。即刻电隔离成功 2 57根 (96% )。平均随访 (2 2 9± 177)d ,随访期内停用所有抗心律失常药物 (部分患者服小剂量β受体阻滞剂 ) ,无房颤发作 65例 (65% ) ,房颤发作明显减少 12例 (2例服用胺碘酮后 ,12 % ) ,总有效率 77%。并发症包括脑卒中 2例 ;肺静脉狭窄 9例 ,其中单支轻度狭窄 7例 ,2支重度狭窄 1例(均为 2次消融 ) ,左上肺静脉完全闭塞 1例 ;术后心包积液 2例。并发症的总发生率为 13 %。结论　(1)使用Lasso导管     

Usefulness of a new radiofrequency thermal balloon catheter for pulmonary vein isolation: a new device for treatment of atrial fibrillation

INTRODUCTION: A rapidly firing or triggered ectopic focus located within a pulmonary vein (PV) or close to the PV ostium could induce atrial fibrillation (AF). The aim of this study was to evaluate the efficacy and safety of a radiofrequency thermal balloon catheter for isolation of the PV from the left atrium (LA). METHODS AND RESULTS: Twenty patients with drug-resistant paroxysmal AF were treated by isolating the superior PVs using an RF thermal balloon catheter. Using a transseptal approach, the balloon, which had an inflated diameter 5 to 10 mm larger than that of the PV ostium, was wedged at the LA-PV junction. It was heated by a very-high-frequency current (13.56 MHZ) applied to the coil electrode inside the balloon for 2 to 3 minutes, and the procedure was repeated up to four times. The balloon center temperature was maintained at 60 degrees to 75 degrees C by regulating generator output. Successful PV isolation was achieved in 19 of the 20 left superior PVs and in all 20 of the right superior PVs and was associated with a decrease in amplitude of the ostial potentials. Total procedure time was 1.8 +/- 0.5 hours, which included 22 +/- 7 minutes of fluoroscopy time. After a follow-up period of 8.1 +/- 0.8 months, 17 patients were free from AF, with 10 not taking any antiarrhythmic drugs and 7 taking the same antiarrhythmic agent as before ablation. Electron beam computed tomography revealed no complications, such as PV stenosis at ablation sites. CONCLUSION: The PV and its ostial region can be safely and quickly isolated from the LA by circumferential ablation around the PV ostia using a radiofrequency thermal balloon catheter for treatment of AF.     

Results of Short‐Term and Long‐Term Pulmonary Vein Isolation for Paroxysmal Atrial Fibrillation Using Duty‐Cycled Bipolar and Unipolar Radiofrequency Energy

PV Isolation Using Bipolar/Unipolar RF Energy . Background: Electrical disconnection of the pulmonary veins (PV) plays an important role in the ablation of paroxysmal atrial fibrillation (AF). Antral ablation using a conventional steerable ablation catheter often is technically challenging and time consuming. Methods: Eighty‐eight patients (mean age 58 ± 11 years) with symptomatic paroxysmal AF underwent ablation with a circular mapping/ablation decapolar catheter (PVAC). Ablation was performed in the antral region of the PVs with a power‐modulated bipolar/unipolar radiofrequency (RF) generator using 8–10 W delivered simultaneously through 2–10 electrodes, as selected by the operator. Seven‐day Holter monitor recordings were performed off antiarrhythmic drugs at 3‐, 6‐, and 12‐month follow‐up, and patients were requested to visit the hospital in the event of ongoing palpitations. All follow‐up patients were divided into 2 groups: Group 1 with a follow‐up of less than 1 year and group 2 patients completing a 1‐year follow‐up. Results: Overall, 338 of 339 targeted PVs (99%) were isolated with the PVAC with a mean of 24 ± 9 RF applications per patient, a mean total procedure time of 125 ± 28 minutes, and a mean fluoroscopy time of 21 ± 13 minutes. Freedom from AF off antiarrhythmic drugs was found in 82 and 79% of group 1 and group 2 patients, respectively. No procedure‐related complications were observed. Conclusion: PV isolation by duty‐cycled unipolar/bipolar RF ablation can be effectively and safely performed with a circular, decapolar catheter. Twelve‐month follow‐up data compare favorably with early postablation results, indicating stable effects over time. (J Cardiovasc Electrophysiol, Vol. 21, pp. 399–405, April 2010)     

Pulmonary Vein Contraction Before and After Radiofrequency Ablation for Atrial Fibrillation

Pulmonary Vein Contraction After Ablation. Introduction: Cardiovascular magnetic resonance imaging (cMRI) may provide a noninvasive method to test for pulmonary vein (PV) isolation after ablation for atrial fibrillation (AF) by detecting changes in PV contraction. Methods: PV contraction (the maximal percentage change in PV cross‐sectional area [CSA] during the cardiac cycle) measured 1 month before and 2 months after PV isolation was compared in 63 PVs from 16 patients with medically refractory AF. Repeat cMRI imaging and invasive catheter mapping was performed prior to repeat PV ablation in 50 PVs from 14 additional patients with recurrent AF. Contraction in PVs with sustained isolation after the initial ablation was compared to contraction in PVs with electrical reconnection to adjacent atrium. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cutoff PV contraction value for prediction of PV‐atrial reconnection after ablation. The cutoff value was then prospectively tested in 40 PVs from 12 additional patients. Results: PV contraction decreased after AF ablation (22.4 ± 10% variation in CSA before ablation vs 10.1 ± 8% variation in CSA after ablation, P < 0.00001). PVs with sustained isolation on invasive mapping contracted less than PVs with electrical reconnection to adjacent atrium (13.7 ± 10.6% vs 21.4 ± 9.3%, P = 0.021). PV contraction produced a c‐index of 0.74 for prediction of PV‐atrial reconnection after ablation and >17% variation in PV CSA predicted reconnection with a sensitivity of 84.6% and specificity of 66.7%. Conclusion: PV contraction is reduced by ablation. PV contraction measurement may provide a noninvasive method to test for PV isolation after ablation procedures. (J Cardiovasc Electrophysiol, Vol. 22, pp. 169‐174, February 2011)     

三维标测系统指导下环肺静脉消融治疗心房颤动

目的 探讨三维标测系统指导下环肺静脉消融治疗心房颤动的安全性和有效性.方法 阵发性心房颤动92例和持续性或永久性心房颤动36例,接受环肺静脉消融术.采用Carto电解剖标测系统,进行环肺静脉左心房线性消融,消融终点为肺静脉电隔离.手术结束时对心律仍为心房颤动者行同步直流电心脏复律.结果 完成"解剖学"环形消融线256条,其中58.6%达到电隔离肺静脉的终点,经寻找缝隙补充消融后最终248条(96.9%)消融线达到终点.手术时间(231±45)min、X线曝光时间(42±13)min和放电时间(66±17)min.术后随访平均10个月,无复发101例(78.9%).接受了再次手术15例,心内电生理检查证实14例有左心房-肺静脉传导,射频消融成功并随访30～270 d,两次射频消融术后总成功率为87.5%,其中阵发性心房颤动成功率为93.0%,持续性或永久性心房颤动为76.7%.并发症发生率为6.2%,包括心包填塞2例、小脑梗死2例、股静脉穿刺部位血肿1例和左侧大量血胸1例,经治疗后均痊愈.结论 以肺静脉电隔离为目标的环肺静脉消融术治疗心房颤动有效和安全.     

Utility of exit block for identifying electrical isolation of the pulmonary veins

INTRODUCTION: Electrical isolation of the pulmonary veins (PVs) to treat paroxysmal atrial fibrillation (AF) has been described using "entry block" as an endpoint for PV isolation. We describe a new technique for guiding PV isolation, using "exit block" out of the PV after ablation as a criterion for successful isolation. METHODS AND RESULTS: A circular mapping catheter was positioned at the os of arrhythmogenic PVs and ablation was performed proximal to the mapping catheter until entry block into the vein was achieved. Pacing was performed from the mapping catheter and from the ablator inside the PV to document exit block out of the PV. In patients in whom cardioversion did not restore sinus rhythm, PV isolation was performed in AF. Entry and exit block were reassessed in ablated veins after a 20-minute waiting period. Ninety-five PVs were ablated in 41 patients. A total of 66 PVs in 34 patients were ablated in sinus rhythm. After entry block was achieved, exit block was present in only 38 (58%) of 66 PVs. A total of 29 PVs in 21 patients were ablated in AF. After cardioversion to sinus rhythm, there was evidence of entry block into the PV in 20 (69%) of 29 PVs and exit block in only 14 (48%) of 29 PVs. There was no significant difference between the total number of lesions applied per vein in sinus rhythm compared with AF (11.6 +/- 8.6 vs 10.3 +/- 6.2; P = NS). There was recovery of conduction after a 20-minute waiting period in 9 (11%) of 84 PVs. CONCLUSION: Identification of exit block after ostial PV ablation provides a clear endpoint for electrical isolation of the PVs. Isolation of the PVs can be performed during sustained AF without the need to apply excess RF lesions. Applying a 20-minute waiting period after electrical isolation will identify reconnection in approximately 10% of PVs.     

Remote magnetic navigation for circumferential pulmonary vein ablation: single-catheter technique or additional use of a circular mapping catheter?

Purpose

Remote magnetic navigation (RMN) is utilized for catheter guidance during pulmonary vein ablation (PVA). We aimed to determine whether the additional use of a circular mapping catheter (CMC) influences efficacy and outcome of RMN-guided PVA.

Methods

A total of 80 consecutive subjects (65 % male, age 62?±?9 years) underwent circumferential PVA with a 3D mapping system and an RMN-guided irrigated catheter. Procedural endpoint was complete PV isolation (PVI), total radiofrequency (RF) time >60 min, or procedure duration >5 h. PVI was defined as an entrance and/or exit block, diagnosed with a CMC within the PV ostium or by pacing via the roving RMN-guided catheter (single-catheter technique). Prolonged Holter monitoring after 3 and 6 months was used to detect atrial tachyarrhythmia (AT/AF) recurrences.

Results

Complete PVI was achieved in 56 % (45/80) of all subjects (isolated PVs per patient, 3.1?±?1.2; RF time, 56.3?±?17.2 min; procedure duration, 3.8?±?0.8 h). Prospective validation of the single-catheter technique for diagnosing PVI demonstrated high concordance (94 %) with blinded CMC results. CMC use in first-time PVA was associated with similar total RF and procedure times but higher PV isolation rate. Upon multivariate analysis, CMC use, female gender, left PV, smaller PV ostium and repeat PVA predicted PVI during RMN-guided ablation. Persistent AF and mitral regurgitation at baseline and the number of non-isolated PVs predicted AT/AF recurrence during follow-up.

Conclusions

Concomitant CMC use for first-time, RMN-guided PVA is associated with similar procedure duration but higher PV isolation rates as compared to a single-catheter approach. Since the number of isolated PVs predicts freedom from AT/AF, CMC utilization appears advisable for first-time, RMN-guided PVA.     

Pressure‐Guided Cryoballoon Isolation of the Pulmonary Veins for the Treatment of Paroxysmal Atrial Fibrillation

Pressure‐Guided Cryoballoon Pulmonary Vein Isolation. Background: Pulmonary vein (PV) isolation using a balloon‐mounted cryoablation system is a new technology for the percutaneous treatment of atrial fibrillation (AF). Complete PV occlusion during balloon ablation has been shown to predict successful electrical isolation. The aim of this study was to correlate mechanical PV occlusion with changes in a pressure curve recorded at the distal tip of the cryoballoon catheter. Methods and Results: We analyzed 51 PVs in 12 patients (61 ± 6 years old) with paroxysmal AF. At first, PV occlusion via the cryoballoon was documented by changes in the pressure curve. Once the PV is occluded, the pressure curve registered in the vein converts from a left atrial pressure curve to a pulmonary artery pressure curve: the PV wedge curve. Occlusion was then confirmed by transesophageal echocardiography (TEE). Following 2 cryoablation applications, electrical PV isolation was assessed with a circumferential mapping catheter. Under the exclusive guidance of changes in the pressure curve at the tip of the cryoballoon, mechanical occlusion confirmed by TEE was achieved in 47 of 51 PVs (92%). Three PVs required further TEE guidance to achieve occlusion. All 50 occluded veins were electrically isolated after cryoablation. One right inferior vein, which could not be occluded with the balloon, displayed conduction post cryoablation and was isolated by focal ablation. Conclusions: Occlusion and electrical isolation of PVs during cryoballoon ablation can be predicted by the appearance of a PV wedge curve at the tip of the catheter. This new straightforward parameter may facilitate the procedure. (J Cardiovasc Electrophysiol, Vol. 21, pp. 120‐125, February 2010)     

Mechanism of recurrence after radiofrequency catheter ablation of atrial fibrillation guided by complex fractionated atrial electrograms

Background A better understanding of the mechanisms of recurrent atrial fibrillation (AF) after radiofrequency ablation of complex, fractionated atrial electrograms (CFAEs) may be helpful for refining AF ablation strategies. Methods and results Electrogram-guided ablation (EGA) was repeated in 30 consecutive patients (mean age = 59 ± 8 years) for recurrent paroxysmal AF, 10 ± 4 months after the first ablation. During the first procedure, CFAEs were targeted without isolating all pulmonary veins (PVs). During repeat ablation, all PVs and the superior vena cava (SVC) were mapped with a circular catheter and the left atrium was mapped for CFAEs. EGA was performed until AF was rendered noninducible or all identified CFAEs were eliminated. During repeat ablation, ≥1 PV tachycardia was found in 83 PVs in 29 of the 30 patients (97%). Among these 83 PVs, 63 (76%) had not been completely isolated previously. During repeat ablation, drivers originating in a PV or PV antrum were identified only after infusion of isoproterenol (20 μg/min) in 12 patients (40%). At 9 ± 4 months of follow-up after the repeat ablation procedure, 21 of the 30 patients (70%) were free from recurrent AF and flutter without antiarrhythmic drugs. Conclusions Recurrence of AF after EGA is usually due to PV tachycardias. Therefore, it may be preferable to systematically map and isolate all PVs during the first procedure. High-dose isoproterenol may be helpful to identify AF drivers.     

Electrophysiologically guided pulmonary vein isolation during sustained atrial fibrillation

INTRODUCTION: Sustained atrial fibrillation (AF) is frequently encountered during pulmonary vein (PV) isolation. The aim of this study was to evaluate the feasibility and safety of PV isolation during sustained AF. METHODS AND RESULTS: Thirty-seven patients (30 men, age 54 +/- 10 years) underwent Lasso-guided isolation of 87 PVs during sustained AF. Baseline PV electrogram patterns were classified into one of two types: organized, with consistent PV activation sequence; or disorganized, with constant variation of PV activation sequence. In disorganized activity, radiofrequency ablation was performed circumferentially around the Lasso while the earliest PV potential was targeted during organized activity. Complete left atrial (LA) to PV block during AF was identified by abolition or dissociation of all sharp potentials recorded within the vein. PV isolation then was verified during sinus rhythm. Baseline activation patterns of PV potential were organized in 32 PVs (37%) [more frequently in inferior veins than superior veins (53% vs 26%, P = 0.01)] and disorganized in 55 PVs (63%). In 59 of 87 PVs, isolation was begun and completed during AF. Radiofrequency ablation organized PV activation sequence in 75% prior to isolation. LA-PV block was confirmed during sinus rhythm in 54 (92%) of 59 PVs. In 28 of 87 PVs, sinus rhythm was restored before complete LA-PV block. Complete isolation was achieved in all 87 PVs without complications. CONCLUSION: PV isolation can be effectively and safely performed during sustained AF, preceded in most cases by organization of PV electrogram activity. This strategy may be the preferred alternative to multiple intraprocedural cardioversions.     

Initial experience using a forward directed, high-intensity focused ultrasound balloon catheter for pulmonary vein antrum isolation in patients with atrial fibrillation

Background: A high-intensity-focused ultrasound balloon catheter (HIFU-BC) is designed to isolate pulmonary veins (PV) outside the ostia (PV antrum). This catheter uses a parabolic CO₂ balloon (behind water balloon) to focus a 20-, 25-, or 30-mm diameter ring of ultrasound forward of the balloon (parallel to catheter shaft). The purpose of this study is to test the safety and efficacy of the HIFU-BC for PV antrum isolation in patients with atrial fibrillation (AF).
Methods and Results: Twenty-seven patients with paroxysmal (19 patients) or persistent (8 patients) AF were studied. Double transseptal puncture was performed for left atrial deployment of a Lasso catheter (for PV mapping) and the 14 Fr HIFU-BC. The HIFU-BC was positioned outside the PV orifice over a guidewire. HIFU energy (acoustic power 45 watts) was applied for 40 seconds with a 20-mm sonicating ring and 40 or 60 seconds with a 25-mm or 30-mm sonicating ring. No other ablation system was utilized. PV antrum isolation was attempted using HIFU-BC in 78 of 104 PVs (25/27 RSPVs, all 23 LSPVs, all 23 LIPVs, all four left common trunks and 3/27 RIPVs). HIFU-BC successfully isolated 68 (87%) of the 78PV antra with 1–26 (median 3) HIFU applications. The complications include transient bleeding from a distal branch of the left superior PV resulting from guidewire manipulation in one patient and right phrenic nerve injury in another patient. No PV stenosis (>50% narrowing) and no LA-esophageal fistula occurred. At the 12-month follow-up, 16 (59%) of the 27 patients were free of symptomatic episodes of AF (only 3 of the 16 patients were receiving antiarrhythmic medications).
Conclusions: Forward-focused HIFU applications isolated PVs outside the PV ostium with elimination of AF in 16 (59%) of the 27 patients at 12 months following the single ablation procedure.