大折返房性心动过速的电解剖标测和导管射频消融

目的应用电解剖标测系统分析3例大折返房性心动过速(房速)的电生理机制并导航消融。方法3例房速患者(男1例,女2例),平均年龄51±12岁,心动过速病史19±11年。常规电生理检查初步确定房速所在心腔,使用电解剖标测系统构建心房三维模型,完成电压和激动标测,分析心动过速的机制并确定缓慢传导区(即关键峡部),使用冷生理盐水灌注导管消融。结果3例患者临床常规检查初步排除结构性心脏病,电压标测均显示被标测心房存在疤痕区。病例1为围绕三尖瓣环顺钟向的大折返房速,关键峡部位于三尖瓣环与后侧壁的疤痕之间。病例2为围绕上腔静脉逆钟向的大折返房速,关键峡部位于右房侧壁疤痕与上腔静脉之间。病例3为左房8字形折返,关键峡部位于左房顶部的两片疤痕之间。3例患者均在关键峡部消融成功,随访9～10个月未见复发。结论电解剖标测可以揭示大折返房速的基质,阐明折返机制,并有效指导消融。     

CARTO标测指导射频消融治疗非峡部依赖性心房扑动的初步研究

初步探讨非峡部依赖性心房扑动 (简称房扑 )———非典型房扑CARTO标测的方法学和射频消融效果。 4例经电生理标测证实的非典型房扑患者 ,男、女各 2例 ,年龄 2 4～ 5 7岁。 1例为先天性心脏病 (简称先心病 )三房心外科术后 ,1例为慢 快综合征。房扑发作时在右房或左房CARTO标测 ,三维重建右房或左房 ,寻找房扑折返径路的关键峡部区域行线性消融。结果 :3例为右房非峡部依赖性房扑 ,1例消融径线为 2条 ,即三尖瓣环至下腔静脉(IVC)口和右房后外侧至IVC ,1例消融径线为右房前中外侧 ,1例为右房下外侧。 1例左房房扑 ,消融径线位于右上肺静脉口下方至卵园窝。 4例均即时消融成功。随访 8～ 2 4个月 ,有 1例先心病术后房扑复发 ,再次行CARTO标测发现房扑折返环位于左房 ,划线消融未成功。结论 :CARTO标测非峡部依赖性房扑有一定的优势 ,能显示房扑折返环和关键峡部 ,并能指导线性消融     

非接触心内膜激动标测系统指导房间隔缺损修补术后Ⅱ型心房扑动的射频消融(附一例报道)

评价非接触球囊导管标测系统 (EnSite 30 0 0 )在指导房间隔缺损 (ASD)修补术后心房扑动 (简称房扑 )的射频消融中的临床应用。 1例女性患者 ,41岁 ,ASD修补术后 2 2年开始频繁发作心动过速 ,体表心电图示Ⅱ型房扑。应用EnSite 30 0 0构建右房三维几何模型 ,标测心动过速的折返激动顺序 ,发现手术疤痕与三尖瓣环之间、下腔静脉与三尖瓣环之间为折返环路的关键峡部 ,应用导航系统指导峡部消融 ,成功阻断心动过速 ;消融后通过起搏标测判定峡部已达完全双向阻滞。随访 2 0个月 ,无心动过速复发。结论 :在ASD修补术后房扑的标测和消融中应用EnSite30 0 0系统是安全有效的 ,不仅能确定折返环路的关键峡部 ,而且能准确判断线性损伤的连续性。     

非接触心内膜激动标测系统指导房间隔缺损修补术后H型心房扑动的射频消融（附一例报道）

评价非接触球囊导管标测系统(EnSite 3000)在指导房间隔缺损(ASD)修补术后心房扑动(简称房扑)的射频消融中的临床应用。1例女性患者，41岁，ASD修补术后22年开始频繁发作心动过速，体表心电图示H型房扑。应用EnSite 3000构建右房三维几何模型，标测心动过速的折返激动顺序，发现手术疤痕与三尖瓣环之间、下腔静脉与三尖瓣环之间为折返环路的关键峡部，应用导航系统指导峡部消融，成功阻断心动过速；消融后通过起搏标测判定峡部已达完全双向阻滞。随访20个月，无心动过速复发。结论：在ASD修补术后房扑的标测和消融中应用EnSite 3000系统是安全有效的，不仅能确定折返环路的关键峡部，而且能准确判断线性损伤的连续性。     

儿童室间隔修补术后远期心房内折返性心动过速的消融

目的报道儿童先天性心脏病室间隔缺损（VSD）术后远期出现的心房内折返性心动过速（IART）的电生理标测及导管消融疗效。方法8例患儿（男、女各4例）,平均年龄（7．1±4．1）岁,VSD术后1～5年发生持续性IART,8例均有左心室扩大,其中5例合并慢性心力衰竭。行心房电生理标测,部分应用三维标测（EnSiteNavX）技术,标测折返环的关键峡部并行导管消融。结果8例均自发IART,折返环关键部位分布：6例位于三尖瓣环峡部,1例于右心房界嵴至下腔静脉间,1例于三尖瓣环9点位置至界嵴问。所有（100％）患儿手术即刻成功,无并发症。平均随访（25．2±16．5）个月,2例复发,其中1例再次消融成功,总成功率7／8（87．5％）。左心室人小及射血分数均明显好转。结论儿童VSD术后IART机制多为三尖瓣环一下腔静脉峡部依赖型心房扑动,可经导管消融治愈或明显改善。三维标测技术能准确快速定位折返环的电生理峡部并指导消融,显著减少曝光时间。     

先天性心脏病外科手术后切口性房性心动过速三维电磁导管标测及射频消融

目的；探讨天先性心脏病外科手术后切口性房性心动过速（房速）三维电磁导管（即Carto)标测特点及射频消融价值。方法：5例切口性房速患者，应用Carto系统标则右心房，实时重建心腔三维电解剖图，标识瘢痕区，观察电热图，传导图，于折返所经过的关键峡部位线性消融，结果：4例房速呈持续性，1例（三房心）术中不能诱发，电势图示低电压区主要分布于右房游离壁，在右房中侧壁下侧壁分别标测到瘢痕区1（S1）和瘢痕区2（S2）。4例持续性房速发生机理与折返有关，折返环位于低电压区，中心解剖障碍区均为中侧壁瘢痕区1，3例折返经过S1－S2，1例经过S1－三尖瓣环之间的关键峡部，于上述关键峡部消融，均获成功，三房心患者（未诱导心动过速）于S1－S及三尖瓣环－下腔静脉之间行线性消融，无并发症，随访2－24个月，其中1例（三房心）于术后1个月出现不典型心房扑动，结论：提示先天性心脏病术后房速的发生机理与折返有关，应用Carto系统标测可清楚地显示折返途径，消融折返所经过的关键峡部可望达到根治目的。     

非接触标测对于典型心房扑动的标测、消融和电生理机制的新认识

目的介绍非接触标测对于典型心房扑动(简称房扑,AFL)的标测、消融和电生理机制的新认识.方法 9例典型AFL,男性7例,女性2例.使用非接触标测对窦律时峡部的双向传导、AFL时的折返激动序列进行详细标测,在导航系统指导下完成后位峡部线性消融,然后验证峡部双向传导阻滞.结果 (1)1例为顺钟向AFL,7均为逆钟向AFL,1例未能诱发AFL,所有AFL平均心房心动周期(215±36)ms;(2)非接触标测三维显示AFL在右房内的整个折返环及其与解剖结构的三维关系;(3)激动可以穿过界嵴上部并且传导相对缓慢,提示右心房平滑部是折返环的一部分;(4)非接触标测可直观显示复发病例的消融线缺口,并直接导航消融;(5)1例术中出现心房颤动,1例因不能耐受消融所致胸痛放弃手术,其余7例即刻均达到峡部双向阻滞,随访12～36月未见复发.结论非接触标测系统可直观再现典型AFL的完整折返环及其与右房解剖结构的关系,确认折返机制,对复发病例可发现消融线裂隙并导航消融.同时发现激动可横向穿过界嵴并且速度缓慢.     

Carto三维标测系统指导房性心动过速射频导管消融的临床分析

目的 探讨Carto三维标测系统指导房性心动过速射频导管消融的方法及疗效.方法 对10例房性心动过速患者应用Carto三维标测系统标测右和/或左心房,实时构建三维电解剖图.判断房性心动过速起源部位及类型.局灶性或大折返性房性心动过速,并于心房最早激动点或折返环的关键峡部消融.结果 10例患者均为局灶性房性心动过速,右心房性8例,其中6例起源于右心房底部(冠状静脉窦口附近2例、间隔部1例、侧壁3例),2例起源于右心房上部(间隔部1例、后壁1例);左心房性2例均起源于左心房右上肺静脉口.所有病例在Carto三维标测系统指导下射频导管消融均获得成功,无并发症,随访5～24个月均无复发.结论 应用Carto三维标测系统标测房性心动过速,对判断房性心动过速起源及类型准确快速,能安全、有效指导射频导管消融,减少X线曝光时间,进一步提高成功率.     

导管消融心脏病术后心房内大折返性心动过速

目的:报道应用常规和三维电生理标测方法经导管消融心脏病术后心房内折返性心动过速(IART)的疗效和安全性。方法:选择2002年1月～2006年2月在我院因心脏病术后心房内折返性心动过速行射频消融的44例患者,早期采用常规电生理标测方法,之后随机采用Carto和Ensite三维标测方法指导导管消融。结果:44例患者共诱发出54种心房内折返性心动过速,其中37种(37/54,68.5%)心房内折返性心动过速心电图表现为典型心房扑动(AFL)锯齿形F波,31种心房扑动(31/54,57.4%;31/37,83.8%)成功靶点在下腔静脉和三尖瓣环(IVC-TA)峡部,4种心房扑动成功靶点在疤痕和下腔静脉峡部,2种心房内折返性心动过速成功靶点在疤痕和三尖环之间。另外17种(17/54,31.5%)心房内折返性心动过速临床心电图表现与典型房扑不同,表现为P’波,其中15种(15/ 54,27.8%)成功靶点在右心房游离壁疤痕—下腔静脉或疤痕—上腔静脉或疤痕与疤痕之间;房间隔补片和上腔静脉之间、房间隔补片和三尖瓣环之间各消融成功1种。随访1例复发,行2次消融成功。1例出现持续性心房颤动伴RR长间歇,植入永久性起搏器。结论:导管消融心脏病术后心房内折返性心动过速具有较高的疗效和安全性,应当作为首选的治疗方法。     

普通型心房扑动的新现象

普通型心房扑动 (AFL)的完整折返环路以及界嵴 (CT)和AFL的关系仍不太清楚 ,笔者应用电解剖 (CARTO)标测系统执行两项研究。Ⅰ :对 12例持续AFL的病人实施右房CARTO标测及多部位拖带。于三尖瓣环 (TA)周围测量传导速度。双电位 (DP)位于右房后下壁 ,相当于解剖上的界嵴 ,从下腔静脉 (IVC)与心房肌的连接处向上、稍前延伸 ,其长度为 40 .9± 7.9mm。所有病人的DP间期从上至下逐渐增加。在 9例逆向AFL病人中 ,右心耳后基底部的后方一狭长心肌位于折返环内 ,结果来自右心耳基底前、后方的两个心房激动波融合于右房下游离壁。在另 3例病人中 (1例顺钟向、2例逆钟向 )右心耳基底部后方未发现位于折返环内 ,迫使折返环仅绕三尖瓣与右心耳基底部前方之间的心肌兴奋右房下游离壁。在AFL的折返环中 ,没有固定的缓慢传导区 ,大部分病人的缓慢传导区位于间隔部和侧壁。Ⅱ :对 7例普通型AFL及 6例非AFL病人 ,在冠状窦起搏下 ,标测右房后壁。通过在右房重建中出现DP确认CT。以 6 0 0 ,30 0ms周长以及静脉注射氟卡胺 (1mg/kg)后以 6 0 0ms周长起搏冠状窦 ,分别测量CT上、中、下部位的刺激信号至双电位中第一及第二个心房激动波的传导时间 (SD1及SD2 )和此部位的电位间期 (DPI)。在AFL病例中 ,与以 6 0 0ms周长起搏冠状     

非接触标测系统用于典型心房扑动的右房标测和导航消融

应用非接触标测系统实施典型心房扑动 (AFL)的右房 (RA)全心腔标测和导航射频消融。 6例典型AFL ,男 5例、女 1例 ,年龄 5 6 .2± 15 .3(35～ 76 )岁。常规放置冠状静脉窦和His束电极 ,将标测球囊置于RA中下部 ,构建RA心内膜模型 ,分别于低位RA和冠状窦口 (CSO)S1S16 0 0ms起搏观察峡部传导 ,诱发并标测AFL的激动顺序和折返路径。 1例为顺钟向AFL ,4例为逆钟向AFL ,1例未能诱发AFL。AFL周期 2 0 7± 34ms,非接触标测可显示整个折返环路、激动顺序和缓慢传导区。AFL的激动可以穿过界嵴上部并且传导相对缓慢 ,提示RA平滑部是折返环的一部分。后位峡部线性消融在导航系统指导下进行 ,无需X线透视。消融完成后重复上述起搏验证峡部双向传导阻滞。除 1例术中出现心房颤动 (AF)外 ,其余病例即刻均达到峡部双向阻滞 ,未出现其他并发症 ,随访 8.1± 6 .7(3～15 )个月未见复发。非接触标测系统可安全、有效和直观地实现典型AFL的右房全心腔标测并导航消融 ,验证峡部双向阻滞 ,减少X线曝光时间和无效放电次数。界嵴在典型AFL时具备传导功能 ,RA平滑部和粗糙部共同参与折返环的组成。     

房性心动过速导管消融进展

Atrial tachycardias (ATs) may be divided into focal and reentrant forms. In recent years, great prngress achieved in catheter ablation of ATs and the success rate of catheter ablatiou has improved dramatically in both focal ATs and reentrant ATs.Focal ATs tend to originate in characteristic locations associated with anatomic structures, such as the erista terminalis,the interatrial septum,the atrioventricular annulus,the coronary sinus,the atrial appendages,the ostial portion of the pulmonary veins. In recent years, successful catheter ablation of focal AT from the nou-coronary aortic sinus, from the mitral annulus-aorta junction, or from the atrial ap-pendages has been reported. Catheter mapping and ablation in the non-coronary aortic sinus should be attempted in patients with narrow P waves on surface ECG and the earliest atrial activation located at the His bundle region. For the cases who had a failed ablation or recur-rence after ablation in the non-coronary aortic sinus,mapping and ablation in the mitral annulus-aorta junction should be considered.Catheter ablation of typical atrial flutter (AFL) has a very high success rate,approximately 100% in some centers. For few difficult cases,several measures can be employed to increase the likelihood of success. Firstly and most importantly,the mechanism of typical AFL other than other ATs should be revaluated and reconfirmed. Other measures include using three-dimensional cardiac electroanatomical mapping system to map the cavotricuspid isthmus (CTI) carefully, using large-curve catheters and/or long guiding sheaths to ensure cath-eter contact across the entire CTI,and employing a large-tip or cooled-tip catheter instead of standard 4 mm-tip ablation catheter.Reentrant ATs usually occur in patients with dilated, severely scarred right or left atria, including previous right or left atriotomy, any form of structural heart disease, or following catheter or surgical ablation of atrial fibrillation. Some reentrant ATs patients present with a large scarred right or left atrium without any other form of structural heart disease, were classified it as "idiopathic arrhythmogen-ic atrial myopathy" by some experts. The earlier experience in mapping and ablation of reentrant ATs came mainly from mapping and ablation of ATs in patients with sugical treatment of congenital heart disease,so the ATs were called "incisional reentrant ATs". In the past decade, the success rate for catheter ablation of reentrant ATs after surgery has improved significantly by combination of electroana-tomical scarred substrate mapping and entrainment mapping. It is noted that the "incisional reentrant ATs" often have multiple reentrant circuits and multiple ATs or coexist with typical AFL, and more than one linear lesions from scar to scar, or scar to anatomical obstacle, or between reentrant isthmuses are needed in most cases.The reentrant ATs after catheter ablation of atrial fibrillation have increased dramatically in recent years, which belong to "iatro-genic reentrant ATs". Different atrial fibrillation ablation approaches have different incidence of reentrant ATs, a few in patients with segmental isolation of the pulmonary vein ostia, more often in patients with circumferential pulmonary vein ablation and most often in pa-tients with stepped ablation of chronic atrial fibrillation (combination of pulmonary vein isolation, linear ablation and ablation of the complex fractionated atrial electrograms). In some cases, mapping and ablation of these reentrant ATs are very difficult.     

右房射频消融术治疗心房扑动

对５例阵发性心房扑动（简称房扑）患者行右房射频消融术。３例单型房扑消融成功，２例复合型房扑／房颤失败。３例成功者随访６个月无复发。房扑与右房内大折返运动有密切关系。射频消融结果与右房结构、房扑的类型及折返运动有关。右房射频消融的远期效果仍有待研究     

Catheter ablation of tachycardias after undergoing a surgical atriotomy using a multipolar electrode catheter: conventional mapping method without an electroanatomical mapping system.

BACKGROUND: A variety of supraventricular tachyarrhythmias may occur in patients after undergoing a surgical atriotomy. The purpose of this study was to characterize them and determine the role of conventional mapping. METHODS AND RESULTS: In 45 patients after a surgical atriotomy, 68 atrial tachyarrhythmias were observed. A conventional mapping system with a 20-pole electrode catheter used in the electrophysiological study detected 39 atrial tachycardias (ATs). Type 1 atrial flutter (AFL) was observed in 23 and reverse type 1 AFL in 4. AT was classified into 3 subgroups, namely, incisional macroreentrant AT (n=31), incisional focal AT (n=1) and non-incisional AT (n=7). In the patients with incisional macroreentrant AT after the standard right atriotomy, the 20-pole electrode catheter placed on the incision could easily record the entire sequence of the atrial activation. Successful catheter ablation was achieved in all patients with incisional reentrant AT. The ablation site of incisional reentrant AT was the isthmus between the incision and the superior vena cava cannulation scar in 4, between the incision and the inferior vena cava cannulation scar in 22, and the area at the septal incision in 3. The remaining 2 incisional ATs were left atrial AT and right atrial transincisional AT. CONCLUSIONS: The conventional mapping system is still very useful for making an electrophysiological diagnosis in patients after a standard right atriotomy.     

Radio-frequency ablation of arrhythmias following congenital heart surgery

BACKGROUND: Cardiac arrhythmias as a late complication following congenital heart surgery are encountered more and more frequently in clinical practice. The use of new electrophysiological methods of visualisation and mapping improves the efficacy of radio-frequency (RF) ablation of these arrhythmias. AIM: To assess patterns of atrial arrhythmias following congenital heart surgery and to examine the efficacy of RF ablation using the electro-anatomical CARTO system. METHODS: Electrophysiological diagnostic study and RF ablation were performed in 24 consecutive patients (mean age 36+/-18 years) who had atrial arrhythmias following congenital heart surgery. The mechanism of arrhythmia (ectopic or reentrant) and strategy of RF ablation procedure were based on the results of the right atrial map performed during index arrhythmia. RESULTS: The patients were divided into five groups according to the type of congenital heart surgery. The ASD group consisted of 17 patients who had undergone in the past surgery due to atrial septal defect, four patients had a history of surgery due to ventricular septal defect (VSD group), and one patient each had undergone surgery due to corrected transposition of the great arteries (ccTGA), tetralogy of Fallot (TF) or dual-outflow right ventricle (DORV). During diagnostic electrophysiological study typical atrial flutter (AFL) was diagnosed in nine patients from the ASD group, atypical AFL in three ASD patients, and ectopic atrial tachycardia (EAT) in six ASD patients. In one patient EAT was induced after ablation of typical AFL. Of the VSD patients, three had atypical AFL, and one had typical AFL. The patient following surgery for ccTGA had atypical AFL and EAT, whereas in the two remaining patients (DORV and TF) atypical AFL was demonstrated. The efficacy of the first session of RF ablation was 83% and no complications were observed. The efficacy of RF ablation of typical AFL was 90%, atypical AFL 78%, and EAT 86% (NS). During the long-term follow-up (24+/-17 months) arrhythmia recurrences were noted in 2 (10%) out of 20 patients who were effectively treated during the first RF ablation session. CONCLUSIONS: Reentry is the most common electrophysiological mechanism of incisional tachycardias, followed by ectopic atrial tachycardia. RF ablation using the electro-anatomical CARTO system is effective and safe in this group of patients.     

Radiofrequency ablation of left atrial flutter mediated with double potentials in a seemingly normally structured heart

Background

Left atrial flutter (left AFL) is common in patients who undergo atrial fibrillation ablation and cardiac surgery; however, few reports describe left AFL in detail in a seemingly normally structured heart, and the mechanisms of the occurrence of such arrhythmia are still not clear. We describe left AFL in patients without prior cardiac surgery or catheter ablation and discuss the electrophysiological characteristics that may explain the preferential generation and perpetuation of such tachycardia.

Methods and results

Eleven patients with left AFL, who had no history of cardiac surgery or interventions, underwent electrophysiological studies and 3-dimensional electroanatomic mapping studies. Echocardiography revealed a relatively mild dilation of the left atrium, mild to moderate mitral regurgitation, and a normal left ventricular ejection fraction. The electroanatomic mapping during tachycardia showed a “reentrant” activation pattern in all patients. The mean tachycardia cycle length was 266 ± 17 ms. A single-loop reentrant circuit was identified in 7 patients. A counterclockwise left atrial flutter evolved around the mitral valve annulus in 6 patients. The tachycardia rotated around the left atrial anterior wall in 1 patient. Four patients exhibited a double-loop reentrant circuit with a “figure of 8” pattern reentry. Double potentials as the critical isthmus of the circuit were identified in the left atrial anterior wall near the mitral annulus which displayed a low-voltage area matched with the left atrium–aorta contiguity. The conduction velocity was significantly slower in the double-potential recording area than in the lateral mitral annulus (0.36 ± 0.03 m/s vs 0.74 ± 0.12 m/s; P < 0.05). Successful ablation around the double-potential recording site caused an interruption of the tachycardia, and remained free of recurrence during a 12-month follow-up in all patients.

Conclusion

Left AFL in patients without a history of surgery or ablation is rarely observed in clinical practice. The successful site of ablation was within the anterior wall near the mitral annulus showing the double potentials as the critical part of the reentrant circuit. This suggests that perhaps a double potential-targeted ablation may be effective for these patients.     

Mechanisms of atrial tachyarrhythmias following surgical atrial fibrillation ablation

INTRODUCTION: Typical and atypical atrial flutters (AFLs) and atrial tachycardias (ATs) have been reported in patients with prior surgical atrial fibrillation ablation. The underlying mechanisms for this group of atrial tachyarrhythmias have not been well characterized and the efficacy of catheter ablation in their treatment is unknown. METHODS AND RESULTS: Twenty patients (6 females) with a surface ECG diagnosis of AFL or AT following surgical atrial fibrillation ablation underwent 26 electrophysiology studies. Patients manifesting sustained, organized, and beat-by-beat reproducible atrial electrical activity underwent complete right and left atrial catheter mapping and catheter ablation. One patient had no inducible tachyarrhythmia, while 5 patients had nonmappable arrhythmias. Nineteen of the 31 potentially mappable atrial tachyarrhythmias were completely characterized in 14 patients. The underlying mechanisms were macro-reentrant left AFL (n = 9), focal left AT (n = 3), typical right AFL (n = 6), and atypical right AFL (n = 1). Of the 19 completely characterized atrial arrhythmias, catheter ablation was performed for 18, and the procedure was successful for 13 of these. After a mean follow-up of 15 +/- 10 months, 15 of 20 patients (75%) were in sinus rhythm including 10 of 13 patients (77%) with AT/flutter ablation. Ten patients, including 6 following ablation, were maintaining sinus rhythm without antiarrhythmic medications. CONCLUSIONS: Patients with an ECG diagnosis of AFL or AT following surgical atrial fibrillation ablation may have multiple tachycardia mechanisms with the right or left atrium as the site of origin. Many of these rhythms may resolve with further maturation of surgical atrial fibrillation ablation (SAFA) lesions or be treatable with antiarrhythmic medication. However, persistent tachyarrhythmias can often be treated successfully with catheter mapping and ablation.     

Non-contact mapping to guide radiofrequency ablation of atypical right atrial flutter.

OBJECTIVES: This study was aimed at evaluating the efficacy of non-contact mapping and ablation of non-incisional atypical right atrial (RA) flutters. BACKGROUND: The majority of atypical RA flutters were reported in patients after surgical incision of the RA. METHODS: The study group consisted of 15 patients (61 +/- 13 years, 8 males) with atypical atrial flutter (AFL). The RA activation during AFL was delineated using a non-contact mapping system (EnSite 3000 with Precision Software, Endocardial Solutions, St. Paul, Minnesota). The narrowest part of each reentrant circuit was targeted using radiofrequency energy. RESULTS: In all 15 patients, non-contact mapping showed AFLs confined to the RA with RA activation time accounting for 100% of the cycle length (210 +/- 19 ms). During single-loop re-entry in seven patients, the activation wave front circulated around the central obstacle (CO) in the anterolateral wall with conduction through the channel between the CO and the crista terminalis (CT). During figure-of-eight re-entry in eight patients, simultaneous upper and lower loop re-entry through the conduction gap in the CT was found in four patients, and simultaneous upper loop and free-wall single-loop re-entry was observed in four patients. Radiofrequency ablation of the free-wall channel and/or CT gap was effective in eliminating these AFLs in 13 patients. During a follow-up of 16.8 +/- 3.8 months, two patients had recurrence of left AFL, and one had recurrence of atrial fibrillation. CONCLUSIONS: Atypical RA flutters could arise from single-loop or double-loop figure-of-eight re-entry. Radiofrequency ablation of the free-wall channel and/or the CT gap was effective in eliminating these arrhythmias.     

Reentry mechanisms and ablation of ECG-typical atrial flutters involving the cavo-tricuspid isthmus and the proximal coronary sinus

Aim

Reentry circuits of a rare typical atrial flutter (AFL) involving the cavo-tricuspid isthmus (CTI) and proximal coronary sinus (CS) are described based on electrophysiological data and effects of radiofrequency (RF).

Methods and results

Twelve patients with ECG-typical AFL in whom entrainment demonstrated that CTI and proximal CS were both part of the circuit were included. Initial RF target was CTI in 8 patients and proximal CS in 4. Success was defined as AFL termination/noninducibility. After CTI ablation, AFL cycle length (CL) increased in all: AFL persisted in 3, while in the other 5 AFL was interrupted but subsequently induced with the same morphology; before induction CTI bi-directional block was validated; success was obtained at the CS, targeting fragmented atrial potentials (APs). In those with first ablation at CS, AFL was interrupted in 3 with no AFL inducibility; in 1 AFL persisted with CL prolongation and was terminated at CTI. Two reentry patterns were identified: in 5 patients the inter-atrial septum as well as the mid-distal CS were outside of the circuit, while the CTI, proximal CS and Bachmann's bundle zone were inside, suggesting a left atrial component; in 1 patient electrophysiological mapping suggested an intra-CS circuit component. RF was successful in all without recurrence.

Conclusion

Electrophysiological mapping and RF effects suggest a continuum between the CTI and proximal CS in rare cases with ECG-typical AFL. RF inside the proximal CS, targeting fragmented APs, should be considered in any patient in whom CTI ablation failed to interrupt a typical AFL.