预激综合征患者多旁路的射频消融

１７４例预激综合征患者中１３例（７．５％）具有多旁路（２９条）。２９条旁路中２１条由基础电生理检查证实，８条在阻断其它旁路后显现。４例在双侧，９例在单侧消融。平均放电３２±１４次后将２７条（９３．１％）旁路阻断。多旁路与单旁路消融成功率相似（９３．１％ＶＳ９４．０％，Ｐ＞０．０５）；但放电次数多（３２±１４ＶＳ１４±１１，Ｐ＜０．０５），消融时程长（３．６±０．８ｈＶＳ２．１±０．９ｈ，Ｐ＜０．０１）；多旁路组复发率高（７．６％ＶＳ１．９％，Ｐ＜０．０１）．本研究证实射频消融是根治多旁路患者的有效方法。     

异丙肾上腺素对射频消融房室结折返性心动过速疗效评价的意义

对消融房室结慢径的７２例房室结折返性心动过速（ＡＶＮＲＴ）病人进行观察分析，以了解异丙肾上腺素在ＡＶＮＲＴ射频消融中的临床价值。消融前电生理检查时有２７．８％（２０／７２）的病人未能诱发ＡＶＮＲＴ，静脉滴注异丙肾上腺素后，８５．０％（１７／２０）则能诱发；消融后４７．９％（３４／７２）用异丙肾上腺素评价，其中８例既有房室结跳跃现象又有心房回波的病人５０．０％（４／８）诱发出ＡＶＮＲＴ而重新消融。随访８．５±４．３个月，成功消融的７１例中，３４例经异丙肾上腺素评价者无一例复发，３７例未用异丙肾上腺素评价者２例复发。提示静脉滴注异丙肾上腺素可提高ＡＶＮＲＴ的诱发率；消融后房室结慢径前传功能存在时，无论有无心房回波均应用异丙肾上腺素评价，以确定消融终点和降低复发率。     

Radiofrequency Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia after Orthotopic Heart Transplantation

Patients with orthotopic heart transplantation may develop a variety of arrhythmias. Successful radiofrequency catheter ablation for tachyarrhythmias from manifest and concealed accessory bypass tracts in transplant patients has been previously reported. We present a patient with orthotopic heart transplantation who developed typical atrioventricular nodal tachycardia, which was successfully treated by radiofrequency catheter ablation.     

Radiofrequency Catheter Ablation of AtypicalAtrioventricular Nodal Reentrant Tachycardia

Ablation of Atypical Atrioventricular Nodal Reentrant Tachycardia, Introduction: Published reports of radiofrequency ablation of atypical atrioventricular nodal reentranttacbycardia (AVNRT) have been limited. We present our experience in 10 consecutive patientswith atypical AVNRT wbo underwent radiofrequency ablation of the "slow" AV nodal pathway.
Methods and Resttlts: there were 9 females and 1 male; their mean age was 44 ± 19 years (± SD), the mean AVNRT cycle length and ventriculoatrial (VA) interval at the His positionduring AVNRT were 340 ± 50 msec and 200 ± 70 msec, respectively. the slow pathway wassuccessfully ablated in all patients with a mean of 10 ± 7 radiofrequency energy applications inthe posteroseptal right atritim near the coronary sinus os. The mean procedure duration was 100 ± 35 minutes. There were no complications. In 4 patients, target sites were identified during sinus rhythm by mapping for possible slow pathway potentials, In the other 6 patients, target sites were identified by mapping retrograde atrial activation during AVNRT or ventricularpacing, The VA times at successful target sites were a mean of 45 ± 30 msec less tban the VAtime at the His cathetcr during AVNRT, There were no differences in success rate, number ofradiofrequency energy applications, or procedure duration between patients in whom mappingwas guided by possible slow pathway potentials or by retrograde atrial activation, During 6 ± 3 months of followup, 1 patient bad a recurrence of atypical AVNRT and underwent a secondablation procedure, which was successful.
Conclusion: Radiofrequency ablation of atypical AVNRT can be safely and effectivelyaccomplisbed when target sites are identified based either on possible slow pathway potentialsduring sinus rbytbm or retrograde atrial activation times during tachycardia.     

快-慢型房室结折返性心动过速的电生理特征和射频消融治疗

报道８例快－慢型房室结折返性心动过速（ＡＶＮＲＴ）的电生理特征及射频消融治疗。其中３例为慢－快型ＡＶＮ－ＲＴ射频消融改良慢径后出现的快－慢型ＡＶＮＲＴ。８例均经消融慢径而成功终止心动过速。平均放电次数３±１．１次、平均放电时间１２０±３０．４ｓ、平均放电功率３０±１１Ｗ。随访６～２４个月，无复发。快－慢型ＡＶＮＲＴ具有以下临床电生理特征：①快径不应期短、慢径不应期长。②心内电刺激无房室结双径路现象。③心动过速能由心房刺激诱发。④心动过速时ＡＨ间期＜ＨＡ间期，冠状窦近端Ａ波最提前。熟悉快－慢型ＡＶＮＲＴ的电生理特征，对于鉴别房性心动过速及右后间隔旁道参与的房室折返性心动过速十分重要，也是指导快－慢型ＡＶＮＲＴ射频消融成功的关键。     

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.     

射频能量测试交界性心律消融房室结折返性心动过速

探讨能量测试法在房室结折返性心动过速 (AVNRT)慢径标测与消融中的作用。将 90例AVNRT患者分成三组 (每组 30例 ) ,分别采用能量测试法、下位法和后位法进行慢径标测与射频消融。能量测试法是在Koch三角区逐步以小剂量多次试验放电标测 ,以出现加速性交界性心律为慢径传导部位 ;从 2 0W开始消融并增至 30W ,持续 12 0s ,以出现加速性交界性心律且逐渐转变为窦性心律为消融有效。能量测试法所需手术标测时间、X线曝光时间和消融能量明显少于后位法 (12 1± 43vs 183± 6 7min ,5 8± 2 1vs 93± 34min ,70 0 0± 470vs 12 0 0 0± 75 0J,P≤ 0 .0 5 ) ,而发生短暂性房室阻滞和交界性心动过速则均较下位法明显减少。慢径消融有效时几乎 10 0 %出现加速性交界性心律 ;慢径传导呈多部位分布。结论 :能量测试法运用于AVNRT慢径标测及消融中 ,能较敏感地揭示慢径传导部位和消融有效的靶点 ,为AVNRT慢径标测消融的有效方法。     

Intracardiac Echocardiography Guided Radiofrequency Catheter Ablation of the Slow Pathway in Atrioventricular Nodal Reentrant Tachycardia

Background: ICE has demonstrated its utility in imaging right atrial structures but its utility in slow pathway (SP) ablation has not been documented in a randomized trial. Methods: The feasibility of using ICE as a imaging modality to identify the effective site of SP ablation was done in part one of the study comprising 10 patients of typical AVNRT. Subsequently, a prospective randomized study was done comparing the conventional (group A) and ICE guided (group B) ablation of the SP. Each group had 20 patients of typical AVNRT. Ablation in the conventional arm was guided by intracardiac electrograms and fluoroscopy. Group B patients underwent SP ablation guided primarily by ICE imaging; fluoroscopy was used mainly for initial placement of catheters. Results: Reliable & stable ICE images were obtained in all patients. Part I of the study showed that RF pulses given when the ablation catheter was seen to cross the atrioventricular muscular septum (AVMS), always resulted in junctional rhythm. In Group B, RF pulse was delivered only when the ablation catheter was at the AVMS making an obtuse angle with the image of the His-bundle catheter. Consistent junctional rhythm and abolition of SP resulted at this site. Compared to group A, patients in group B required fewer pulses (mean 1.4±0.6 vs. 4.4±3.0; p < 0.05, median 1 vs. 5; p < 0.01), achieved a higher temperature (56±4 °C vs. 50±6 °C) and had more frequent junctional rhythm (100% vs. 70%) during RF pulse. Conclusions: A critical portion of SP exists adjacent to Tricuspid valve overlying the AVMS. ICE imaging consistently and reliably localizes this site and RF applications here result in interruption of antegrade SP conduction.     

Radiofrequency Catheter Ablation of Three Accessory Pathways in a Single Session

Radiofrequency Ablation of Multiple Accessory Pathways. A 19-year-old patient is described having three accessory atrioventricular pathways. All three pathways were ablated using radiofrequency current in a single electrophysiologic investigation. (J Cardiovasc Electrophysiol, Vol. 3, pp. 141–149, April 1992)     

Case Report: Radiofrequency Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia in a Patient with Heart Transplantation

Ten years after orthotopic cardiac transplantation, a 56-year-old man developed recurrent presyncope and syncope. A 24-hour ambulatory electrocardiographic recording did not document significant arrhythmic events. A head-up tilt table test was negative. An electrophysiologic study revealed dual atrioventricular (AV) nodal physiology and inducible typical atrioventricular nodal reentrant tachycardia (AVNRT). The patient became hypotensive and presyncopal during AVNRT. Radiofrequency (RF) catheter ablation successfully eliminated AVNRT without complications. The patient remained free of symptoms at nine months follow-up.     

特殊类型房室结折返性心动过速的电生理机制及其射频消融

报道２例特殊类型的房室结折返性心动过速（ＡＶＮＲＴ），１例为慢－慢型ＡＶＮＲＴ伴起始部多径路逆传；１例为两种不同电生理特性的慢径交替前传、快径逆传构成的ＡＶＮＲＴ。电生理检查均提示房室结三径路。２例病人均于冠状静脉窦口上方消融慢径改良房室结成功，心动过速不再被诱发。随访２个月心动过速均无复发。提示房室结多径路形成的特殊类型ＡＶＮＲＴ，需详细的电生理检查并仔细鉴别方能予以诊断。射频导管消融方法同典型ＡＶＮ－ＲＴ，且安全、有效。     

Successful Cryoablation of Atrioventricular Nodal Reentrant Tachycardia and Coexisting Accessory Pathways without Fluoroscopy

We report the case of a 14‐year‐old boy patient admitted to our outpatient clinic with palpitations and documented supraventricular tachycardia. Electrophysiological study and ablation were planned. In the electrophysiological study, two tachycardias with different cycle lengths and morphologies were induced. After elimination of the slow pathway, left posterior accessory pathway was detected and successfully ablated. Another pathway was detected following that ablation. Due to the slow retrograde conduction of this pathway, diltiazem infusion was started to uncover the accessory pathway. The second accessory pathway was at the left posteroseptal region and was successfully ablated. After a 30‐minute waiting period, no tachycardia was induced. In addition, no fluoroscopy was used during the procedure.     

射频消融治疗房室结折返性心动过速对心率变异性的影响

对１０例房室结折返性心动过速患者采用频域、时域法分析射频消融前后心率变异，旨在了解射频消融后自主神经系统对窦房结的支配有否改变。结果显示心率变异的高频段（ＨＦＰ）、低频段（ＬＦＰ）成分较射频前有所减低，ＬＦＰ／ＨＦＰ之比（２．２０±１．３１ＶＳ５．１０±３．３２）明显增高（Ｐ＜０．０１）．提示射频消融后迷走神经功能相对减低，对窦房结的支配减弱。提出消融快径不但易并发ＩＩＩ度房室传导阻滞，而且易并发窦性心动过速。消融慢径则可防止窦性心动过速的发生。     

单导管射频消蚀预激综合征患者的左侧旁路

以单导管法对3例体表心电图有delta波的预激综合征患者行射频消蚀。据心电图定位旁路后,将一根消蚀导管经右股动脉插入左室,在二尖瓣环左室侧标测到旁路电位后以该导管放电,全部成功。平均放电5次,平均操作时程1.3小时。本观察提示,单导管是消蚀部分显性预激患者房室旁路的简便、安全和有效的方法。     

房室结改良时发生完全性房室阻滞的特征性心电改变

探讨经导管射频消融 (RFCA)治疗房室结折返性心动过速 (AVNRT)时发生完全性房室阻滞 (Ⅲ度AVB)前的特征性心电改变。回顾分析自 1996年 1月至 1999年 12月RFCA治疗AVNRT放电过程有完整心内电图记录者 486例。放电过程中有室房 (VA)阻滞、快速交界心律 (≥ 16 0bpm)和 /或房室 (AV)阻滞称为特征性心电改变。Ⅰ组 387例 ,任何一次放电过程中无特征性心电改变 ;Ⅱ组 99例 ,有一次或一次以上放电过程中有特征性心电改变。Ⅱ组中有特征性心电改变的放电共 316次 ,即刻停止放电组 (Ⅱa组 ) 2 19次 ,指发现特征性心电改变后 2s以内停止放电 ;延迟停止放电组 (Ⅱb组 ) 97次 ,指发现特征性心电改变 2s后停止放电。结果 :①AVNRT消融总成功率 97.9%(4 76 /4 86 ) ,永久性Ⅲ度AVB 0 .41% (2 /4 86 )。②特征性心电改变中VA阻滞占 72 .5 % (2 2 9/316 )、快交界心律占2 0 .6 % (6 5 /316 )、AV阻滞占 7.0 % (2 2 /316 )。③Ⅲ度AVB(包括一过性和永久性 )发生率为 2 .3% (11/4 86 ) ,其中Ⅰ组为 0 (0 /387)、Ⅱ组为 11.1% (11/99) ,P <0 .0 0 0 1。④Ⅱa组Ⅲ度AVB发生率为 0 .9% (2 /2 19)、Ⅱb组Ⅲ度AVB发生率为 9.3% (11/97) ,P <0 .0 0 1。RFCA改良房室结治疗AVNRT时Ⅲ度AVB均发生在特征性心电改变之后 ,发现特征?     

Electrophysiologic Characteristics and Radiofrequency Catheter Ablation in Atrioventricular Node Reentrant Tachycardia with Second-Degree Atrioventricular Block

Second-Degree AV Block During AVNRT. Introduction : Detailed electrophysiologic study of AV nodal reentrant tachycardia (AVNRT) with 2:1 AV block has been limited.
Methods and Results : Six hundred nine consecutive patients with AVNRT underwent electrophysiologic study and radiofrequency catheter ablation of the slow pathway. Twenty-six patients with 2:1 AV block during AVNRT were designated as group I, und those without this particular finding were designated as group II. The major findings of the present study were: (1) group I patients had better anterograde and retrograde AV nodal function, shorter tachycardia cycle length (during tachycardia with 1:1 conduction) (307 ± 30 vs 360 ± 58 msec, P < 0.001), and higher incidence of transient bundle branch block during tachycardia (18/26 vs 43/609, P < 0.001) than group II patients: (2) 21 (80.8%) group I patients had alternans of AA intervals during AVNRT with 2:1 AV block. Longer AH intervals (264 ± 26 vs 253 ± 27 msec, P = 0.031) were associated with the blocked beats. However, similar HA intervals (51 ± 12 vs 50 ± 12 msec, P = 0.363) and similar HV intervals (53 ± 11 vs 52 ± 12, P = 0.834) were found in the blocked and conducted beats; (3) ventricular extrastimulation before or during the His-bundle refractory period bundle could convert 2:1 AV block to 1:1 AV conduction.
Conclusions : Fast reentrant circuit, rather than underlying impaired conduction of the distal AV node or infranodal area, might account for second-degree AV block during AVNRT. Slow pathway ablation is safe and effective in patients who have AVNRT with 2:1 AV block.     

Radiofrequency Catheter Ablation of Accessory Pathways:

RF Catheter Ablation of APs. Catheter ablation techniques are now advocated as the first line of therapy for arrhythmias caused by accessory pathways (APs). The most common energy source is radiofrequency current, but technical characteristics vary. Several parameters can be used to determine the optimal target site: AP potential, AV time, atrial or ventricular insertion site, or unipolar morphology. Specific considerations are needed depending on AP location. Despite the different approaches described, there is no significant difference in the reported success rate, which is over 90%. However, the number of radiofrequency applications needed to achieve ablation appears to differ significantly, with median values from 3 to 8 reported. A combination of criteria related to both timing and direction of the activation wave-front or use of subthreshold stimulation could improve the accuracy of mapping. In patients with "resistant" APs, different changes in ablation technique must be considered during the procedure to achieve elimination of AP conduction. The incidence of complications in multi-center reports is close to 4%, with a recurrence rate of 8%. The long-term safety of catheter ablation requires further study.     

冷冻消融与射频消融治疗房室结折返性心动过速的比较

目的:比较经导管冷冻消融与射频消融治疗房室结折返性心动过速(AVNRT)的临床效果及安全性.方法:根据治疗方法将83例经电生理检查确诊为AVNRT的患者分为冷冻消融组(冷冻组,n=41)和射频消融组(射频组,n=42).比较两组的临床特征、成功率、手术时间及复发率等.结果:两组一般临床特点无明显差异.冷冻组的手术时间明显比射频组长[(119.14±40.16)min vs (85.86±28.24)min,P=0.001],差异有统计学意义.冷冻组和射频组消融即刻成功率相似(97.6% vs 100.0%,P=0.309),差异无统计学意义.冷冻组较射频组一过性房室传导阻滞(AVB)的发生率稍高(15.0% vs 11.9%,P=0.681),但差异无统计学意义,且两组均无完全AVB发生.两组患者在平均(11.6±5.5)个月的随访期内均无AVNRT复发.结论:冷冻消融治疗AVNRT与射频消融一样有效且安全.冷冻消融可作为AVNRT的常规消融方式之一.     

房室结折返性心动过速射频消融术中特殊病例分析

在２６０例房室结折返性心动过速（ＡＶＮＲＴ）射频消融中出现１１例特殊病例。其中男３例、女８例。５例属电生理现象复杂，其中１例快－慢型者Ｓ１Ｓ１５００ｍｓ心室刺激时，连续３个刺激便出现室房文氏现象，随之出现心动过速，ＡＶＮＲＴ时心室率１８２ｂｐｍ，Ｈｉｓ束电极Ａ波最先激动，呈Ａ－Ｈ－Ｖ传导，ＶＡ间期２２０ｍｓ，ＶＡ＞ＡＶ；另１例快－慢型者心内电生理诱发出典型ＡＶＮＲＴ，其频率１６２ｂｐｍ，对其慢径改良后，诱发出另一种频率的快－慢型ＡＶＮＲＴ。３例慢－慢型者心动过速较易诱发，ＡＶＮＲＴ时均以冠状静脉窦口（ＣＳＯ）Ａ波最提前，Ｈｉｓ束电极示Ｈ－Ｖ－Ａ传导。３例永存左上腔静脉，ＣＳＯ异常扩张，窦口上缘几乎接近Ｈｉｓ束水平。３例放电过程特殊者，其中１例在较大范围内消融，均出现慢交界区心律，另１例在消融中出现一个交界区心律后，便诱发ＡＶＮＲＴ，再有１例为消融时难以出现慢交界律。所有病例均消融成功（１００％）。结果提示对特殊病例除应进行详细电生理检查之外，应采取不同的消融策略     

Cryothermal Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia in a Pediatric Patient after Atrioventricular Canal Repair

Anatomic displacement of the atrioventricular node and associated conduction tissue in atrioventricular septal defects has been previously described. In spite of the increasing use of cryothermal catheter ablation in the pediatric population, there remains very little literature regarding its use in congenital heart disease. We describe successful cryothermal modification of the slow atrioventricular nodal pathway in a 12-year-old patient with a previously repaired partial atrioventricular septal defect and inducible atrioventricular nodal reentrant tachycardia. The use of a steerable catheter to locate the displaced His signal combined with the use of cryothermal energy allowed for the safe and effective treatment of this patient's tachycardia.