心电图P波形态变化在典型心房扑动射频消融中意义的再评价

目的以峡部消融线上标测到稳定的宽间期双电位作为典型心房扑动(AFL)射频消融(RFCA)终点标准,对消融前后低侧位右房与冠状窦口刺激心电图P波形态变化进行比较,进而评价其临床应用意义。方法24例典型AFL患者,进行三尖瓣环至下腔静脉之间的线性消融。消融后于消融线标测双电位。消融前后,以及消融过程中分别进行低侧位右房与冠状窦口刺激,比较心电图P波形态的变化。结果RFCA成功后行低侧位右房及冠状窦口起搏,所有患者体表心电图Ⅱ,Ⅲ,aVF导联的P波在负向成分之后出现一正向波成分(100%),且P波时限延长,但是6例患者出现特征性心房激动顺序变化时(即低侧位右房刺激时呈顺钟向传导,逆钟向阻滞。冠状静脉窦刺激时呈逆钟向传导,顺钟向阻滞),消融线局部双电位为71.0±11.2ms,此时低侧位右房与冠状静脉窦口刺激也出现相同的P波变化,继续消融可见双电位延长至118.20±10.2ms,而再予刺激,并不出现P波形态的进一步变化(25%)。结论:对于典型AFL的射频消融治疗,峡部消融后进行峡部两侧刺激可以产生心电图P波形态的特征性变化。但是由于峡部为缓慢传导或者残存传导裂隙时也可以出现此种变化,加之影响P波形态的因素较多,所以这种判断方法临床实践应用的意义不大。     

导管射频消融Ⅰ型心房扑动的方法学评价

比较在心房扑动 (AFL)时、冠状静脉窦口 (CSO)或低外侧右房 (LRA)起搏下和窦性心律 (简称窦律 )下消融Ⅰ型AFL的优缺点。 48例阵发性AFL随机分为AFL消融组、起搏消融组和窦律消融组 ,对下腔静脉口和三尖瓣环之间的后峡部作线性消融 ,终点为后峡部双向传导阻滞。比较三组患者的电生理参数、急性成功率和远期效果。结果 :三组均达到后峡部双向阻滞 ,随访 2 1.8± 5 .6个月无AFL复发。AFL消融组在AFL终止后均不能达到后峡部双向阻滞 ,需继续在起搏下消融。起搏消融组的操作和曝光时间、放电能量和次数小于其他两组 (P <0 .0 5 )。三组在后峡部双向阻滞后记录局部心房双电位的阳性率为 37.5 %。结论 :①对Ⅰ型AFL采用窦律消融法、起搏消融法和AFL消融法都能取得满意的近远期疗效。②后峡部双向传导阻滞是保证近远期疗效的重要消融终点。③在消融部位标测到双电位可作为消融有效的指标 ,但不能代替后峡部双向阻滞作为消融终点。④起搏消融法的操作和曝光时间、放电能量和次数明显少于在AFL和窦律下消融 ,可作为常规方法使用     

导管射频消融1型心房扑动的方法学评价

比较在心房扑动 (AFL)时、冠状静脉窦口 (CSO)或低外侧右房 (LRA)起搏下和窦性心律 (简称窦律 )下消融Ⅰ型AFL的优缺点。 48例阵发性AFL随机分为AFL消融组、起搏消融组和窦律消融组 ,对下腔静脉口和三尖瓣环之间的后峡部作线性消融 ,终点为后峡部双向传导阻滞。比较三组患者的电生理参数、急性成功率和远期效果。结果 :三组均达到后峡部双向阻滞 ,随访 2 1.8± 5 .6个月无AFL复发。AFL消融组在AFL终止后均不能达到后峡部双向阻滞 ,需继续在起搏下消融。起搏消融组的操作和曝光时间、放电能量和次数小于其他两组 (P <0 .0 5 )。三组在后峡部双向阻滞后记录局部心房双电位的阳性率为 37.5 %。结论 :①对Ⅰ型AFL采用窦律消融法、起搏消融法和AFL消融法都能取得满意的近远期疗效。②后峡部双向传导阻滞是保证近远期疗效的重要消融终点。③在消融部位标测到双电位可作为消融有效的指标 ,但不能代替后峡部双向阻滞作为消融终点。④起搏消融法的操作和曝光时间、放电能量和次数明显少于在AFL和窦律下消融 ,可作为常规方法使用     

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     

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。     

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.     

射频消融心房扑动拖带刺激的电生理特征

探讨射频消融心房扑动 (简称房扑 )拖带刺激的电生理特征 ,更好的理解房扑机制 ,以期提高消融成功率、减少复发率。 5例阵发性典型房扑患者 ,诱发房扑后 ,在高位、低位右房 ,冠状窦口 (CSO)及右房下部的峡部分别进行拖带刺激 ,分析心房激动顺序 ,然后进行三尖瓣环至下腔静脉之间的线性消融。 5例房扑折返环均为逆钟向旋转 ,峡部 ,高位、低位右房及CSO呈现隐匿拖带 ,左房和卵圆窝呈现显性拖带 ,平均放电 9± 6次 ,均达到右房峡部双向阻滞。CSO起搏时体表心电图Ⅱ、Ⅲ、aVF导联P波形态发生改变。结论 :隐匿、显性拖带对判断峡部依赖性逆钟向房扑有较高价值 ,CSO起搏时心内电图激动顺序和体表心电图P波改变可做为判断峡部消融达到双向阻滞的标志     

消融线径同侧心房近-远端起搏检测右心房峡部完全性阻滞的意义

射频消融阻断下腔静脉至三尖瓣环间的右心房峡部是治疗典型心房扑动（房扑）的有效方法。目前，多采用消融后分别起搏峡部两侧，观察心房激动顺序的变化或消融线径上的宽间期双电位来检测峡部完全阻滞的存在。本文提出另一种可靠而快捷的方法，对判断峡部完全性阻滞有较大价值。     

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     

P波形态改变和消融部位双电位与下腔静脉-三尖瓣环峡部完全性阻滞

目的 探讨下腔静脉一三尖瓣环峡部(简称峡部)完全性双向阻滞的心电图和电生理表现。方法对18倒心房扑动患者的峡部进行线性射频消融，峡部发生完全性阻滞后．起搏刺激冠状静脉窦口和右房下侧壁，观察分析I导联P波形态和消融部位双电位。结果18倒患者均消融成功并发生蛱部完全性双向阻滞，并且I导联P波呈负正双向；对12例患者标测消融部位，均记录有特征性双电位，其敏感性为100％。结论心电图I导联P波形态改变和消融部位特征性双电位是判定蛱部完全性阻滞的可靠标志。     

DP+1: another simple endpoint for atrial flutter ablation

Background:  When double potentials (DP) on the line of block are difficult to see, we propose another simple method to verify complete bidirectional block (CBDB) at the end of an atrial flutter ablation. We measured the interval between the electrograms immediately on either side of the line of block on a multipole catheter spanning the isthmus. We called this interval "DP+1" because it is one pair of electrodes away from the DP on the line of block.
Methods:  Fifty consecutive patients (age 62 ± 13 years, LVEF 54 ± 11%, mean cycle length 241 ± 34 ms) underwent an atrial flutter ablation using a duodecapolar catheter with 2–10 mm spacing with the distal tip inserted into the mid-coronary sinus and the rest of the poles spanning the isthmus and the low lateral right atrium. Radiofrequency ablation was performed using a 10-mm tip electrode (EP Technologies). The ablation endpoint was the creation of a craniocaudal activation pattern of the opposite wall to the pacing site (septal and lateral of the line of block).
Results:  The ablation endpoint was achieved in 48 of 50 (96%) patients with 8 ± 2 RF applications. Adequate DP were found in only 22 of 50 patients (44%), but the DP+1 interval was measurable in all patients. When no block was present, the DP+1 interval was 81 ± 10 ms, and 160 ± 18 ms when complete bidirectional block was present (P < 0.001). A DP+1 interval of >140 ms had 100% specificity, 96% sensitivity, 100% positive predictive value for verifying complete bidirectional block. After a follow-up of 528 ± 253 days, there were no recurrences of AFL, but there were four recurrences of AF (8%).
Conclusion:  When DP cannot be seen, another simple method for verifying CBDB in ablation of typical atrial flutter is a DP+1 interval > 140 ms.     

Recording of double atrial potentials as a marker for isthmus block during ablation of atrial flutter

Radiofrequency ablation is an established method for treatment of type I atrial flutter. The assessment of creation of complete bidirectional isthmus block following linear ablation of the isthmus is an integral part of ablation procedure. Conventionally, bidirectional isthmus block is tested by pacing on either side of ablation line and looking for reversal of activation sequence in the right atrium. We looked at the feasibility of recording double potentials, separated by an isoelectric interval along the ablation line as an alternative method to demonstrate bidirectional isthmus block. An attempt was made to record the double potentials following linear ablation of the cavotricuspid isthmus. Following ablation, bidirectional isthmus block was also tested by pacing from the coronary sinus os and the low-lateral right atrium. We could demonstrate double potentials in 9 of the 11 patients in whom we attempted to record them following linear ablation of flutter. The presence of bidirectional block by pacing from coronary sinus os and low lateral right atrium could be demonstrated in 10 (91%) patients. Thus, double atrial potentials, separated by an isoelectric interval can be demonstrated following ablation of atrial flutter. Double potentials, if demonstrable on coronary sinus os and low lateral right atrium pacing, could serve as an alternative marker of isthmus block.     

Incremental Pacing for the Diagnosis of Complete Cavotricuspid Isthmus Block During Radiofrequency Ablation of Atrial Flutter

Incremental Pacing for the Diagnosis of Cavotricuspid Isthmus Block.   Background: Complete conduction block of the cavotricuspid isthmus (CTI) reduces atrial flutter recurrences after ablation. Incremental rapid pacing may distinguish slow conduction from complete CTI conduction block.
Methods and Results: Fifty-two patients (67 ± 9 years) undergoing 55 CTI ablation procedures were included. With ablation, double potentials (DPs) separated by an isoelectric line of ≥30 ms were obtained. Incremental atrial pacing (600–250 ms) was performed from coronary sinus (CS) and low lateral right atrium (LLRA). A <20 ms increase in the DPs distance during incremental pacing was indexed as complete CTI block. In 8 patients, an initial <20 ms DPs distance increase was noted; direct complete isthmus block was suggested and no additional ablation performed. In the remaining, the CTI line was remapped for conduction gaps and additional radiofrequency energy pulses applied. Complete block, as indexed by incremental pacing, occurred in 46 of 55 procedures, with one flutter recurrence (follow-up 8 ± 2 months): DPs interval variation of 116 ± 20 to 123 ± 20 ms (CS), P = 0.21; and 122 ± 25 to 135 ± 35 ms (LLRA), P = 0.17. The remaining 9 patients (persistent rate-dependent DPs increase) presented 3 flutter recurrences, P = 0.01: DP distance from 127 ± 15 to 161 ± 18 ms (CS), P < 0.001; and 114 ± 24 to 142 ± 10 ms (LLRA), P = 0.007.
Conclusion: Incremental pacing distinguishes complete CTI block from persistent conduction. Such identification, accompanied by additional ablation to achieve block, should minimize flutter recurrences after ablative therapy. (J Cardiovasc Electrophysiol, Vol. 21, pp. 33–39, January 2010)     

Differential Pacing for Distinguishing Slow Conduction from Complete Conduction Block of the Tricuspid-Inferior Vena Cava Isthmus after Radiofrequency Ablation for Atrial Flutter—Role of Transverse Conduction through the Crista Terminalis

Background: Partial conduction block has been suggested a predictor of recurrence of atrial flutter (AFL).Aim: The aim of this study was to assess transverse conduction by the crista terminalis (CT) as a problem in evaluating isthmus block and the usefulness of differential pacing for distinguishing slow conduction (SC) and complete conduction block (CB) across the ablation line.Methods: We assessed 14 patients who underwent radiofrequency catheter ablation of the eustachian valve/ridge–tricuspid valve isthmus for typical AFL. Activation patterns along the tricuspid annulus (TA) suggested incomplete CB across the isthmus. In these patients, atrial pacing was performed from the low posteroseptal (PS) and anteroseptal (AS) right atrium (RA) while the ablation catheter was placed at the ablation line where double potentials (DPs) could be recorded. The pattern of activation of the RA free wall was assessed by a 20-pole catheter positioned along the CT during pacing from the coronary sinus (CS) ostium (CSos) and low lateral RA (LLRA).Results: Faster transverse conduction across the CT resulted in simultaneous or earlier activation of the distal halo electrodes than of the more proximal electrodes, suggesting incomplete conduction block across the isthmus. CB (13) and SC (1) were detected as changes in the activation times of the first and second components of DPs (DP1, DP2) during PS RA pacing and AS RA. Similar changes in the activation times DP1 and DP2 during AS RA pacing as compared to PS RA reflected SC through the isthmus, whereas increased DP1 activation time and decreased of DP2 activation time reflected complete conduction block across the isthmus.Conclusions: Transverse conduction across the CT influences the sequence of activation along the TA after isthmus ablation. Differential pacing can distinguish SC from complete conduction block across the ablation line in the isthmus.     

Characterization of double potentials in human atrial flutter: studies during transient entrainment

Double potentials, defined as atrial electrograms with two discrete deflections per beat separated by an isoelectric interval or a low amplitude baseline, have been observed during right atrial endocardial mapping of human atrial flutter. In this study, bipolar atrial electrograms were recorded during atrial flutter (mean cycle length 235 +/- 27 ms [+/- SEM]) from the high right atrium, the His bundle region, the coronary sinus and at least 30 right atrial endocardial mapping sites in 10 patients. Double potentials were recorded from the right atrium in all patients during atrial flutter. Double potentials were evaluated during transient entrainment of atrial flutter by rapid high right atrial pacing in 5 of the 10 patients. In four of these five patients during such transient entrainment 1) one deflection of the double potential was captured with a relatively short activation time (mean interval 89 +/- 45 ms) and the other deflection was captured with a relatively long activation time (mean interval 233 +/- 24 ms), producing a paradoxical decrease in the short interdeflection interval from a mean of 75 +/- 20 ms to a mean of 59 +/- 24 ms; and 2) the configuration of the double potential remained similar to that observed during spontaneous atrial flutter. On pacing termination 1) the two double potential deflections were found to be associated with two different atrial flutter complexes in the electrocardiogram (ECG); 2) the previous double potential deflection relation resumed; and 3) when sinus rhythm was present, the double potentials were replaced by a broad, low amplitude electrogram recording at the same site.(ABSTRACT TRUNCATED AT 250 WORDS)     

Atrial flutter ablation: correlation between isthmic activation times and flutter cycle.

BACKGROUND: Ablation of typical atrial flutter relies on the suppression of electrical conduction along the cavo-tricuspid isthmus. Bidirectional isthmus block is a criterion of successful ablation and is associated with the presence of different activation times on each side of the ablation line. OBJECTIVE: The aim of this study was to determine whether the difference in isthmic activation times correlates with the length of the atrial flutter cycle. POPULATION AND METHODS: We studied 31 patients with typical atrial flutter (93.6% male, mean age 66 +/- 9 years) who underwent successful ablation during tachycardia. CARTO electroanatomic mapping was used to confirm diagnosis of isthmus-dependent atrial flutter, guide the ablation line creation and assess its efficacy. At the end of the procedure, a three-dimensional activation map of the right atrium was constructed, under pacing from the coronary sinus ostium (with a 500 ms cycle). Activation times on the lateral (right) and septal (left) sides of the ablation line were measured. The difference between these two activation times was termed the difference in isthmic activation times (delta IAT), and was compared to the flutter cycle length. RESULTS: Mean activation times were 173.7 +/- 34.3 ms on the lateral border of the ablation line and 19.1 +/- 12.5 ms on the septal border. Mean delta IAT was 154.6 +/- 27.8 ms and mean atrial flutter cycle length was 257.5 +/- 30.6 ms. delta IAT and flutter cycle length were significantly correlated (r = 0.503, p = 0.0039). The linear regression equation that best described this result was: delta IAT = 37 + (0.46 x flutter cycle). CONCLUSION: After atrial flutter ablation, a difference in isthmic activation times of more than half the flutter cycle length was associated with isthmus conduction block.     

Linear Ablation of Right Atrial Free Wall Flutter: Demonstration of Bidirectional Conduction Block as an Endpoint Associated With Long‐Term Success

Ablation of Right Atrial Free Wall Flutter. Introduction: Ablation for atypical atrial flutter (AFL) is often performed during tachycardia, with termination or noninducibility of AFL as the endpoint. Termination alone is, however, an inadequate endpoint for typical AFL ablation, where incomplete isthmus block leads to high recurrence rates. We assessed conduction block across a low lateral right atrial (RA) ablation line (LRA) from free wall scar to the inferior vena cava (IVC) or tricuspid annulus in 11 consecutive patients with atypical RA free wall flutter. Method and results: LRA block was assessed following termination of AFL, by pacing from the ablation catheter in the low lateral RA posterior to the ablation line and recording the sequence and timing of activation anterior to the line with a duodecapole catheter, and vice versa for bidirectional block. LRA block resulted in a high to low activation pattern on the halo and a mean conduction time of 201 ± 48 ms to distal halo. LRA conduction block was present in only 2 out of 6 patients after termination of AFL by ablation. Ablation was performed during sinus rhythm (SR) in 9 patients to achieve LRA conduction block. No recurrence of AFL was observed at long‐term follow‐up (22 ± 12 months); 3 patients developed AF. Conclusion: Termination of right free wall flutter is often associated with persistent LRA conduction and additional radiofrequency ablation (RFA) in SR is usually required. Low RA pacing may be used to assess LRA conduction block and offers a robust endpoint for atypical RA free wall flutter ablation, which results in a high long‐term cure rate. (J Cardiovasc Electrophysiol, Vol. 21, pp. 526‐531, May 2010)     

Validation of double-spike electrograms as markers of conduction delay or block in atrial flutter

Recent mapping studies of atrial flutter have shown that fragmented electrograms can be found in most cases from the posterior, posteroseptal and posterolateral walls of the right atrium. The fragmentation pattern most often consists of a double spike. To further assess double-spike electrograms as a possible marker of conduction delay, bipolar electrograms were continuously recorded during atrial overdrive pacing of common flutter from the right atrium (7 patients) and from the proximal coronary sinus (5). Baseline double-spike separation of 50 to 130 ms was unchanged in 1 patient and slightly increased (5 to 25 ms) in 4 by coronary sinus pacing. The electrogram sequence was unchanged and the surface morphology was similar to that of basal flutter. Right atrial pacing decreased double-spike separation by 25 to 85 ms from basal values of 45 to 175 ms (23 to 83%), suggesting fusion in the area of fragmented electrograms. These findings suggest that double-spike electrograms represent activation on both sides of a conduction delay zone. The changes induced in these electrograms by pacing from the anterior right atrium and the coronary sinus are consistent with flutter circuits rotating counterclockwise (frontal plane) in the posterior right atrial wall in common atrial flutter.