对比观察射频消融右房后位峡部和间隔峡部治疗典型心房扑动的疗效

对比观察射频消融右房后位峡部和间隔峡部治疗心房扑动 (简称房扑 )两种方法的疗效。 41例房扑患者随机分为后位峡部组 ( 18例 )和间隔峡部组 ( 2 3例 ) ,消融线径分别为三尖瓣环—下腔静脉和三尖瓣环—欧氏嵴。成功消融终点为房扑不能诱发和峡部呈完全性双向阻滞。结果 :40例消融成功 ( 97.6 % ) ,无并发症。后位峡部组 3例和间隔峡部组 2例在首选消融方法失败后 ,改用另一种消融方法获得成功。两组患者的放电次数和手术时间均无显著性差异。平均随访 12 .4± 6 .8个月 ,在后位峡部消融成功者中 ,有 2例房扑复发。结论 :射频消融右房后位峡部和间隔峡部治疗房扑均安全有效 ,两种方法互补可以提高消融的成功率     

峡部依赖性心房扑动对心房颤动发作的影响

目的观察导管射频消融治疗峡部依赖性心房扑动(房扑)对心房颤动(房颤)发作的影响,进一步探讨房扑和房颤的关系。方法86例房扑患者,其体表心电图均提示典型房扑,男性54例、女性32例,年龄50.0±15.6(11～74)岁,病程5.6±6.4(0.1～30)年。将所有患者分成A、B两组,A组为房扑合并房颤患者,共25例;B组为不合并房颤患者,共61例;其中A组同时合并房室结折返性心动过速(AVNRT)3例,房室折返性心动过速(AVRT)4例,阵发性房性心动过速(PAT)10例;B组合并房室结折返性心动过速5例,房室折返性心动过速7例。对峡部依赖性房扑者,线性消融下腔静脉—三尖瓣环峡部致双向传导阻滞;房室折返性心动过速者行旁道消融术;房室结折返性心动过速者行慢径改良术,阵发性房速术中持续或可诱发,予以射频消融。平均随访27.1±14.1(6～63)月。结果A组25例患者中,术后68%(17/25)患者不再发作房颤;其余8例仍有房颤发作,其中1例为术前同时合并房室折返性心动过速,5例为合并阵发性房速。61例术前不合并房颤者,术后随访中有16.4%(10/61)新发房颤。86例患者中,6例因病态窦房结综合征行起搏器植入术,随访未诉心悸、胸闷,心电图为窦性心律与起搏心律交替出现。结论房扑可能与房颤具有共同的发生基质,也可以是房颤的触发因素,成功消融房扑后可以阻止房颤的发生。但房颤发生机制多样,消融峡部依赖性房扑,仍会发生房颤,术前合并房颤或房速者是最强的预测因子。     

典型心房扑动对心房颤动导管消融复发的影响

目的 评价典型心房扑动(房扑)对心房颤动(房颤)导管消融复发的影响.方法 120例药物治疗无效的阵发性房颤患者在三维电解剖标测系统和肺静脉环状标测电极导管联合指导下行环肺静脉电隔离.其中17例(14.2%)合并典型房扑(房扑组,其余作为对照组),行三尖瓣环峡部消融,三尖瓣环峡部消融终点为三尖瓣环峡部双向阻滞.房颤复发定义为导管消融3个月后发生房性快速心律失常.结果 房扑组房颤病程(9.8±10.7)年,长于对照组(5.9±6.3)年,差异有统计学意义(P=0.036).房扑组与对照组相比,年龄、性别、合并器质性心脏病、左心房直径、左心室射血分数差异无统计学意义.随访91～401(237±79)d,房扑组房颤复发率为47.1%,对照组房颤复发率为12.6%,两组间差异有统计学意义(P=0.001).经校正年龄、房颤病程、合并器质性心脏病、左心房直径等因素,Cox多因素分析发现消融术前合并房扑是房颤复发的独立危险因素(危险比3.52,95%可信区间1.32～9.34,P=0.012).结论 典型房扑可能增加房颤导管消融术后房颤的复发,房颤导管消融前应对患者是否合并典型房扑进行认真评价.     

典型心房扑动的经导管射频消融治疗

回顾分析 35例典型心房扑动 (简称房扑 )患者电生理检查和射频消融治疗的临床结果。心内激动标测显示沿三尖瓣环 (TA)逆钟向折返性房扑 2 7例 ,顺钟向折返 2例 ,同时存在二种折返 6例。 8例行TA峡部拖带起搏者均呈隐匿性拖带 ,起搏后间期与房扑周长差值为 1± 4(- 3～ 5 )ms。采用TA峡部双线性消融、后峡部或 /和间隔峡部消融的方法治疗所有患者均成功。 15例以房扑不能再诱发为手术终点 ,随访 10例 ,3例复发 ,复发率 30 % ;2 0例达到TA峡部双向阻滞 ,随访 19例 ,1例复发 ,复发率 5 % ,两组比较P <0 .0 5。随访的 2 9例中 ,7例发生心房颤动 (简称房颤 ) ,发生率 2 4%。与无房颤发作者相比 ,合并器质性心脏病、心房扩大和有房颤病史者的比例明显增加 (6 / 7比 9/ 2 2 ,6 / 7比 4/ 2 2和 7/ 7比 2 / 2 2 ,均P <0 .0 5 )。结果表明 ,心内激动标测结合拖带起搏技术可确定典型房扑的诊断 ,后峡部或间隔峡部消融是治疗房扑的有效方法 ,以TA峡部双向阻滞为手术终点较房扑不能被再诱发为终点可明显降低复发率。房扑消融术后发生房颤与合并器质性心脏病、心房扩大和术前存在房颤有关     

三尖瓣峡部线性消融在心房颤动治疗中的效果

三尖瓣峡部是典型房扑折返环中的缓慢传导区域,对这一解剖结构进行线性消融以达到双向传导阻滞是典型房扑的一线治疗方法。房颤与典型房扑内在关系密切,一方面房颤与典型房扑往往共存于同一患者,另一方面房颤患者在电生理检查中常可见到典型房扑的诱发。因此在房颤射频消融术中常常补充三尖瓣峡部线性消融,以期病人获得更好的远期预后。但最近的研究对这一术式的疗效提出了质疑。本文以两种心律失常的内在联系为切入点,就三尖瓣峡部消融在房颤射频消融术中的疗效进行综述。     

单纯三维电解剖标测系统指导与图像融合技术辅助下环肺静脉线性消融治疗心房颤动的临床对比分析

目的 评价三维电解剖(Carto)标测系统合并图像融合(Merge)技术指导下行环肺静脉线性消融术治疗心房颤动(房颤)的临床疗效,并与单纯用Carto系统治疗组比较.方法 回顾性分析2005年3月至2007年1月间接受导管射频消融术的连续68例房颤患者,其中单纯 Carto标测系统指导下手术患者11例(A组), Carto-Merge技术指导下手术患者57例.消融策略先行左房肺静脉电隔离,必要时加行左房碎裂电位消融 左房顶部、底部、峡部 右房三尖瓣峡部、上腔静脉、冠状静脉窦口部消融.结果 A组平均X线透视时间56.24±13.92 min,平均随访15.08±1.82个月,7例(57.14%)术后3个月生活质量明显改善,无房颤发作;其中阵发性房颤手术成功率为60%,2例接受第二次消融后治愈.B组平均X线透视时间33.32±13.84 min,平均随访8.97±6.28个月,51例(89.47%)术后3个月生活质量明显改善,无房颤发作;其中阵发性房颤手术成功率达95.12%;其X线透视时间,总体及阵发性房颤手术成功率均与A组有明显差异;B组中3例扩张型心肌病和1例肥厚型心肌病房颤消融成功,术后心功能明显改善.结论 在Carto-Merge技术指导下行环肺静脉线性消融术治疗房颤能提高手术效率及成功率,进一步减少X线曝光时间.左房肺静脉电隔离 左房碎裂电位消融 左房顶部、底部、峡部 右房三尖瓣峡部、上腔静脉、冠状窦口的消融可能通过改良心房基质而提高房颤手术成功率.     

术中峡部传导间期百分比对典型心房扑动导管消融终点判定的有效性评估

目的 通过术中测量三尖瓣-下腔静脉峡部（CTI）依赖心房扑动（房扑）消融前后峡部传导间期百分比,探讨峡部传导间期百分比在CTI线性阻滞消融终点评估的临床价值。方法 本研究入组2021年2月至2023年2月诊断CTI依赖房扑并行射频消融治疗患者共37例（首都医科大学附属北京安贞医院35例,河北省儿童医院2例）,术中均诱发CTI依赖房扑,并采用解剖消融方法沿三尖瓣环至下腔静脉行线性消融,术后经右心房激动标测验证CTI呈线性阻滞。分别统计入组患者心动过速周长（TCL）、冠状窦起搏下消融前局部传导间期（P-ABL1）、冠状窦起搏下消融后局部传导间期（P-ABL2）,计算局部传导期间百分比（P-ABL2/TCL）。评估P-ABL2/TCL对诊断CTI双向传导阻滞的价值,并通过消融后激动顺序验证其有效性。结果 所有入组患者均采用解剖方法行射频消融,并行激动标测验证CTI呈线性阻滞。术中诱发TCL为（310.00±46.32）ms。术前测定P-ABL1为（92.16±27.65）ms,术后测量P-ABL2为（173.65±16.35）ms,两组数据差异有统计学意义（P <0.001）。术后P-...     

环肺静脉射频消融联合不同消融径线与心房颤动射频消融术后复发的关系

目的探讨不同消融径线对心房颤动射频消融治疗后复发的影响。方法通过随访2001年至2010年10月在我院行心房颤动射频消融治疗的120例患者,统计有无房性心律失常复发,并回顾分析所有患者的射频消融手术径线,根据手术记录将所有病例分为环肺静脉+单一径线消融组和环肺静脉+联合径线消融组,环肺静脉+单一径线消融组内再分为左房顶线组、二尖瓣峡部组、三尖瓣峡部组和CFAE组,探讨不同径线消融与复发的关系。结果 120例患者成功完成心房颤动射频消融治疗,其中有8例患者复发后再次手术,手术即刻成功率100%。在随访中共有27例患者复发,房颤22例,房扑8例,房速1例。1.在回归分析中,左房顶线组(P=0.136)和二尖瓣峡部组(P=0.08)与复发无关,三尖瓣峡部组(P=0.007)和CFAE组(P=0.044)与复发相关。2.在无复发生存分析中,环肺静脉+单一径线消融组内,左房顶线组(P=0.176)、二尖瓣峡部线组(P=0.06)不能降低心房颤动的复发,三尖瓣峡部线组(P=0.006)、CFAE消融组(P=0.035)则可以降低心房颤动的复发;而在环肺静脉+联合径线消融组(P=0.035)亦不能降低心房颤动的复发。结论环肺静脉联合三尖瓣峡部或CFAE消融治疗心房颤动能有效减少房颤和房扑的复发。     

欧氏瓣对老年人Ⅰ型心房扑动射频消融的影响

目的探讨欧氏瓣对Ⅰ型心房扑动(简称房扑)导管射频消融即刻效果的影响。方法28例老年Ⅰ型房扑患者(呈逆钟向折返18例,顺钟向折返10例)在透视解剖标志和Halo电极三尖瓣环标测电图指引下,在房扑发作或冠状窦口起搏时以温控方式消融位于三尖瓣口和下腔静脉口之间的后峡部,消融方向从三尖瓣叶右室侧到下腔静脉开口。预设温度70℃,每点消融30s,每次移动消融电极3～5mm。观察下列指标:①房扑终止和后峡部阻滞时消融电极在消融线上所处的位置;②房扑终止后峡部残存传导间隙在消融线上所处的位置;③房扑终止后继续消融致后峡部完全阻滞的最终消融部位。结果根据右前斜位30°透视影像测得后峡部平均弧长(即消融线)为38.6±9.7mm。28例全部达到后峡部完全阻滞的消融终点,无并发症。与欧氏瓣有关的房扑终止率为100%(17/17),与欧氏瓣有关的后峡部完全阻滞发生率为92.9%(26/28)。结论欧氏瓣是Ⅰ型房扑后峡部消融线终点的重要标志,线性消融时欧氏瓣心室侧易残存传导间隙,消融该部位的残存传导间隙是Ⅰ型房扑后峡部消融的重要环节。     

冷冻消融治疗阵发性心房颤动合并典型心房扑动一例

患者男性,78岁,因阵发性心房颤动(简称房颤)在接受冷冻球囊进行肺静脉电隔离术中转为典型心房扑动(简称房扑),遂将冷冻球囊放置三尖瓣峡部进行冷冻消融并成功终止房扑,起搏证实峡部双向传导阻滞.临床随访无房颤、房扑复发.     

Evaluation of an individualized strategy of cavotricuspid isthmus ablation as an adjunct to atrial fibrillation ablation

Objectives: To evaluate supplementary cavotricuspid isthmus (CTI) ablation as an adjunct to atrial fibrillation (AF) ablation in selected patients.
Background: It is unclear whether routine CTI ablation is beneficial in all patients undergoing AF ablation.
Methods and Results: In patients undergoing AF ablation, additional CTI block was created only for those with typical atrial flutter (Afl) before or during the ablation. Out of 188 consecutive patients (108 male, 56 ± 9 years), 75 underwent CTI ablation (Group CTI+) and left atrial (LA) ablation (circular mapping-guided extensive pulmonary vein isolation in all and linear LA ablation when required), while 113 underwent LA ablation alone (Group CTI−). Group CTI+ patients had smaller LA and less frequently persistent/permanent AF and linear LA ablation. Over a follow-up of 30 ± 10 months, complications (4% vs 5%, P = NS), typical Afl occurrence (1.3% and 2.6%, P = NS) and AF recurrence (25% and 28%, P = NS) were similar. Atypical Afl was more common in Group CTI− (4 vs 14%, P = 0.026). Eighty-two percent and 79% of patients in Groups CTI+ and CTI−, respectively, remained arrhythmia free in stable sinus rhythm without antiarrhythmic drug treatment (P = NS).
Conclusions: Avoiding supplementary CTI ablation in AF ablation patients without evidence of typical flutter does not result in a higher incidence of typical Afl. Despite more persistent/permanent AF and larger LA in patients without evidence of typical flutter, a strategy of selective supplementary ablation resulted in similar and low AF recurrence rates in the group without CTI ablation compared with the group with CTI ablation.     

Incidence of atrial fibrillation post-cavotricuspid isthmus ablation in patients with typical atrial flutter: left-atrial size as an independent predictor of atrial fibrillation recurrence

Introduction: Atrial fibrillation and atrial flutter often coexist. The long-term occurrence of atrial fibrillation in patients presenting with atrial flutter alone is unknown. We report the long-term follow-up in patients who underwent cavotricuspid isthmus ablation for treatment of lone atrial flutter.
Methods and Results: Between January 1997 and June 2002, 632 patients underwent cavotricuspid isthmus ablation for the treatment of typical atrial flutter at the Cleveland Clinic Foundation. Three hundred sixty-three patients were included in this study and followed for a mean duration of 39 ± 11 months. The mean duration of atrial flutter symptoms was 12 ± 5 months. Mean left-atrial size and left-ventricular ejection fraction were 4.2 ± 0.8 cm and 47 ± 13%, respectively. After a mean follow-up time of 39 ± 11 months, 13% (48 of 363) of the patients remained in sinus rhythm. Five percent (18 of 363) of patients experienced recurrence of atrial flutter only. Sixty-eight percent (246 of 363) experienced the onset of atrial fibrillation and 14% (51 of 363) experienced recurrence of atrial flutter and the new onset of atrial fibrillation. Overall, 82% (297 of 363) of the patients experienced new onset of drug refractory atrial fibrillation. Left-atrial size was a predictor of atrial fibrillation recurrence post-atrial flutter ablation.
Conclusion: At long-term follow-up, approximately 82% of patients post-cavotricuspid isthmus ablation for atrial flutter developed drug refractory atrial fibrillation. This finding suggests that elimination of atrial flutter might delay, but does not prevent, atrial fibrillation. Evidence suggests both arrhythmias may share common triggers and such patients may derive a better long-term benefit from anatomical ablative treatment of atrial fibrillation as well.     

单导管标测在心房扑动射频消融中的意义

目的:探讨单导管标测法在心房扑动(房扑)射频消融中的应用方法和效果。方法:阵发性心房颤动并发房扑患者行肺静脉电隔离术时采用单导管标测法消融房扑30例。所有患者行肺静脉电隔离术后,将10极冠状静脉窦(CS)导管远端2对电极放置于CS内,余位于CS外,并使之有一定的张力,使导管贴靠于三尖瓣环和低右房。用冷盐水灌注消融导管线性消融三尖瓣峡部,房扑发作患者在房扑下消融,窦律患者在CS远端电极起搏下消融,可在术中随时把大头消融导管置于希氏束部位,用于评价是否已完全达双向阻滞,即:起搏CS远端电极,刺激信号至CS近端电极A波的距离大于至希氏束A波的距离,则CS口至低右房单向阻滞;CS近端电极起搏,刺激信号至CS远端电极A波的距离大于至希氏束A波的距离,则低右房至CS口单向阻滞,从而达双向阻滞,CS近端电极起搏所需电压较高,有的患者可达24mA。结果:所用阵发性心房颤动并发房扑患者均成功行三尖瓣峡部线性射频消融,达到双向阻滞,无手术相关并发症,随访4个月～2年,无房扑复发。结论:单导管标测法对房扑患者行三尖瓣峡部线性射频消融操作简单、快速,可完全用于评价消融结果,成功率高,并且节省手术费用。     

Preliminary results with percutaneous transcatheter microwave ablation of typical atrial flutter

Background: Linear microwave ablation has been shown to be effective for treatment of atrial fibrillation during open-heart surgery by producing transmural lesions in the atrium to isolate the pulmonary veins. However, the safety and efficacy of percutaneous, transcatheter, linear microwave ablation for atrial arrhythmias, while demonstrated in animal models, is unknown in humans. Therefore, we studied the safety and efficacy of linear microwave ablation of the cavotricuspid isthmus (CTI) in humans with typical atrial flutter, utilizing a 2-cm long microwave antenna mounted on a steerable 9-French catheter.
Methods and Results: In seven consecutive patients, multielectrode catheters were positioned at the His bundle (quadripolar) and around the TV annulus (duo-decapolar) for pacing and recording atrial activation sequence before and after ablation. The microwave antenna was withdrawn gradually from tricuspid annulus towards inferior vena cava to ablate the CTI. Intracardiac ultrasound was used to ensure adequate endocardial contact of the microwave ablation catheter with the CTI. Microwave energy was applied at a power of 18 to 21 W at each ablation point for 120 seconds. Ablation was repeated until bidirectional CTI block was confirmed by demonstrating a descending activation wavefront in the contralateral atrial wall during pacing from the coronary sinus ostium or low lateral right atrium, respectively. Bidirectional isthmus block was achieved in all patients, after a mean number of 27.4 ± 14.7 energy applications per patients. There were no acute procedural complications.
Conclusions: Percutaneous, transcatheter microwave ablation of CTI dependent atrial flutter was demonstrated to be safe and effective in this preliminary feasibility study.     

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.     

Incidence and predictive factors of atrial fibrillation after ablation of typical atrial flutter

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 fibrillation. Treatment with antiarrhythmic and antithrombotic agents should also be adapted to these factors.     

Concealed Automaticity From an Island of Atrial Myocardium Post Cavotricuspid Ablation

Island of Atrial Myocardium Post Cavotricuspid Ablation. We report the case of a patient with paroxysmal atrial fibrillation in whom 2 previous cavotricuspid isthmus (CTI) ablations were performed for recurrent type I counterclockwise atrial flutter. One year after the last CTI ablation, the patient underwent pulmonary vein isolation for AF and reassessment of conduction block in the CTI was performed during the procedure. While mapping the CTI, activations were documented within the CTI that were dissociated from both right atrial and ventricular activity during sinus rhythm and pacing maneuvers. This dissociated activity was confined to a region delimited by the 2 previous ablation lines, the tricuspid annulus and the inferior vena cava. These findings suggest that an island of atrial myocardium with automatic activity was created within the CTI by previous ablation lines. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1408‐1409, December 2010)     

Characteristics of the Cavotricuspid Isthmus in Predicting Recurrent Conduction in the Long-Term Follow-Up

Background: The characteristics of cavotricuspid isthmus (CTI) in patients with atrial fibrillation (AF) and flutter that may predict recurrence of flutter is not known. We aimed to investigate the CTI characteristics in patients who underwent a second ablation procedure for recurrent AF after previous combined pulmonary vein (PV) and CTI ablation.
Methods: Among 196 consecutive patients with drug-refractory symptomatic AF who underwent PV isolation and CTI ablation with bidirectional isthmus block, 49 patients (age 50 ± 12 years, 43 males) had recurrent AF and received a second procedure 291 ± 241 days after the first procedure. Right atrial angiography for the evaluation of the CTI morphology, and the biatrial contact bipolar electrograms were obtained before both procedures.
Results: In the second procedure, 11 (group 1) of the 49 patients demonstrated recovered CTI conduction. Compared with the patients without CTI conduction (group 2, n = 38), group 1 patients had a higher frequency of a pouch-type anatomy (82% vs 13%, P < 0.001), longer CTI (34.0 ± 8.6 vs 25.5 ± 7.5 mm, P = 0.01), longer ablation time, and larger number of radiofrequency applications; furthermore, the preablation bipolar voltage decreased along both the CTI and ablation line in group 2, whereas it remained similar in group 1 in the second procedure.
Conclusions: A high (22%) percentage of CTIs exhibited recurrent conduction in the long-term follow-up. The CTIs with recurrent conduction had a higher incidence of a pouch and longer length compared with those without recurrent conduction.     

Reduction in Atrial Flutter Ablation Time by Targeting Maximum Voltage: Results of a Prospective Randomized Clinical Trial

Background: Radiofrequency ablation (RFA) of the cavotricuspid isthmus (CTI) is an established therapy for typical atrial flutter. Previous studies have demonstrated that the CTI is often composed of discrete muscle bundles, and evidence has suggested that these bundles correlate with high-voltage local electrograms in the tricuspid isthmus. This randomized, multicenter clinical trial was designed to prospectively compare the hypothesis that a maximum voltage-guided (MVG) technique targets critical conducting bundles in the isthmus, as reflected by a reduction in ablation requirements compared to the anatomical approach to atrial flutter ablation.
Methods: Bidirectional block was achieved in patients undergoing ablation for typical atrial flutter using 1 of 2 randomly assigned methods. The anatomical approach produced a contiguous line of ablation lesions from the inferior aspect of the tricuspid annulus to the inferior vena cava using a standard method. The MVG technique sequentially targeted the maximum voltage local electrograms in the CTI along a similar line.
Results: Sixty-nine patients were randomized, with mean age 63 ± 10 and 58 (84%) male. Among patients in the anatomic group (n = 34), mean ablation time was 11.2 ± 7.5 minutes compared to 5.9 ± 3.3 in the MVG group (n = 35) (P = 0.0026). A mean of 14.2 ± 9.7 ablation lesions were created in the anatomic group, and 7.9 ± 4.8 in the MVG group (P = 0.0042).
Conclusions: Ablation for atrial flutter using an MVG technique results in significantly less ablation requirements than the traditional approach, potentially by concentrating ablation lesions on the muscle bundles responsible for transisthmus conduction.