房室旁道间歇性逆传阻滞的探讨

为探讨房室旁道间歇性逆传阻滞的发生机制及临床意义,对房室旁道患者射频导管消融术中作腔内电生理检查,观察房室顺传和室房逆传功能及途径。结果显示２６１例中有７例（４例为隐匿性预激综合征）为旁道逆向（或双向）传导阻滞（２．７％）。尽管旁道间歇性逆传阻滞是一种少见现象,但由于旁道传导阻滞,无法对旁道进行定位及射频导管消融,因此了解旁道有无间歇性逆传阻滞,对射频导管消融治疗有临床意义。     

快频率依赖性室房逆传左侧隐匿性房室旁道参与的心动过速及射频导管消融

目的探讨快频率依赖性室房逆传特性左侧隐匿性房室旁道的电生理特点及射频消融。方法对8例心电图显示窄QRS波群心动过速的患者行电生理检查,分析房室、室房传导情况、心动过速特点、旁道定位,并行射频消融。结果8例患者均证实存在快频率依赖性室房逆传特性左侧隐匿性旁道,在较慢频率起搏右心室时旁道逆传发生阻滞,而以中等频率起搏时表现为间断旁道逆传,较快频率起搏时才表现为旁道1：1传导且均诱发了房室折返性心动过速,于快频率心室刺激下标测消融靶点,消融均获成功。结论左侧隐匿性房室旁道有时可发生快频率依赖性室房逆传现象,并伴发房室折返性心动过速,在射频消融中需注意分辨,以免漏诊。     

间隙性逆传阻滞房室旁道参与的心动过速及射频消融

目的研究间隙性逆传阻滞房室旁道参与的心动过速特点及射频消融术。方法6例患者,男性3例,女性3例,年龄24~58岁,其中A型预激1例,B型预激1例,采用右室心尖部和左室S1S1及S1S2起搏分析室房传导情况、心动过速特点、旁道位置确定及射频消融。结果左前游离壁2例,左侧壁1例(A型预激),左后壁旁道2例,右侧三尖瓣环10点处1例(B型预激)。所有旁道具有1:1室房传导功能,6例患者均有间隙性旁道逆传阻滞,均呈2:1室房逆传阻滞。在右室起搏下或窦性心律下标测靶点,所有病例均消融成功。结论不论隐匿性或显性房室旁道均可发生间隙性室房逆传阻滞,电生理检查及射频消融过程中应注意分辨偶发室房逆传阻滞现象,以免漏诊。     

隐匿性房室旁道体表心电图定位

近年来采用射频导管消融（下称消融）阻断房室旁道的传导后可根治其引起的快速性心律失常,故术前对房室旁道定位具有重要的临床意义。体表心电图是临床诊断心室预激最简单、常用的方法,根据各导联预激波极性不同及胸导联移行区的判断,能对显性房室旁道作出定位。隐匿性房室旁道因无顺传功能,无法根据预激波进行旁道定位。但此类旁道具有较强的逆传功能,     

依赖异丙肾上腺素逆传的房室折返性心动过速

目的：探讨4例依赖异丙肾上腺素逆传的房室折返性心动过速的发作情况及电生理特点。方法：对4例射频导管消融前常规电生理检查未能诱发出阵发性定性心动过速及A－H间期跳跃，亦未见旁道逆传者，静脉滴注异丙肾上腺素、右心室刺激时发现左侧旁道逆传，并均诱发出正向型房室折返性心运过速；停止注射后，左侧旁道逆传功能消失，亦不能诱发出房室折返性心动过速。结果：静脉滴注异丙肾上腺素，右心室起搏下用逆行法于二尖瓣环心室侧消融，4例均获成功；术后静脉滴注异丙肾上腺素下再行右心室起搏，未见旁道逆传现象。结论：部分隐匿性旁道构成的房室折返性心动过速发作依赖异丙肾上腺素，射频导管消融在静脉滴注异丙肾上腺素及右心室起搏下进行。     

射频消融术后出现延迟性房室阻滞五例

报道5例射频消融后出现的房室阻滞及其临床转归和电生理特点。1219例房室结折返性心动过速行下位法消融慢径,208例右后间隔旁道参与的心动过速行右后间隔消融,共有5例出现延迟后(>24h)的房室阻滞。慢径消融组的患者3例分别于术后第2,3,5天出现Ⅱ度Ⅰ型房室阻滞,并于术后第4,9和14天消失。后间隔旁道消融的2例患者于第2天出现Ⅱ度Ⅰ型房室阻滞,并分别于第11,13天消失。射频消融放电20.6±8.7(11～31)次,能量30±17.2(20～50)W。放电过程中无快速的交界区心动过速或者>1个无逆传的连续交界区心律。5例在射频消融前后房室结前向和逆向传导功能均正常。结论:慢径和后间隔旁道消融均可出现延迟性房室阻滞,通常能在1～2周内恢复。     

慢径消融时出现交界区心律伴室房逆传阻滞意义的再探讨

目的探讨慢径消融过程中出现交界区心律伴室房逆传阻滞的意义。方法房室结折返性心动过速经射频消融治疗患者,共91例。采用由低至高的逐点递进的方法进行消融,放电中注意观察交界区心律伴逆传阻滞现象的出现。结果所有病例均获得手术成功,其中3例首次消融后复发。91例手术中有47例曾出现交界区心律伴逆传阻滞,与无逆传阻滞组相比较,手术时间及曝光时间无明显差异,但放电次数多于后者;在共计309次有效放电中,95次有室房逆传阻滞,与214次无逆传阻滞者相比较,其靶点与His束电极间垂直距离明显小于后者,伴发一过性房室传导阻滞(AVB)的比例亦明显大于后者(12.63%vs 2.39%),多元Logistic回归分析发现靶点到HBE电极间垂直距离≤1.5 cm是房室前传阻滞的独立相关因素(OR=12.50,P=0.018),而交界区心律伴逆传阻滞与AVB间相关性不明确(P>0.05)。结论在消融慢径的过程中,出现交界区心律伴逆传阻滞与房室前向传导阻滞之间并无明确的相关性,而消融靶点过高则是出现AVB的独立危险因素。     

射频消融治疗具有快频率依赖性室房逆传特性的旁道

目的报道具有快频率依赖性室房逆传特性的房室旁道电生理检查及射频消融结果。方法4例患者,均有阵发性心悸史,且发作时心电图均显示为窄QRS波心动过速,按常规方法接受心脏电生理检查及射频消融治疗。结果4例均证实存在旁道的快频率依赖性室房逆传,且均诱发了房室折返性心动过速,室房逆传最早激动部位均为左房。于快频率心室刺激下标测消融靶点,消融均获成功。结论旁道的快频率依赖性传导为一种少见电生理现象,可伴发房室折返性心动过速。     

频率依赖性隐匿性房室旁道伴发的心动过速及射频消融

目的　研究频率依赖性隐匿性房室旁道伴发的心动过速特点及射频消融治疗。方法　6例患者 ,男性 2例 ,女性 4例 ,年龄 14～ 6 8岁。电生理检查包括采用右室心尖部和左室S1S1及S1S2起搏分析室房传导情况、心动过速特点、旁道位置确定及射频消融治疗。结果　左侧游离壁 5例 ,右侧三尖瓣环 11点处 1例。具有旁道 1∶1室房传导功能 5例 ,传导窗口 80～ 10 0ms,有偶发旁道逆传现象 4例 ,诱发心动过速 5例。在右室起搏下标测靶点 ,所有病例均消融成功。结论　隐匿性房室旁道发生 3位相或 4位相阻滞时表现为频率依赖性室房传导。电生理检查过程中应注意分辨偶发室房逆传现象 ,以免漏诊。     

心房颤动时显性房室旁道的射频消融治疗

对 2 6例预激综合征患者于心房颤动 (简称房颤 )时射频消融显性房室旁道。其中左侧旁道 9例、右侧旁道17例 ,2 2例有阵发性房颤史。房颤发作伴旁道前传时的心室率为 171± 32 ( 132～ 2 37)bpm。采用经主动脉逆行法或穿间隔法消融左侧旁道、经股静脉途径消融右侧旁道 ,以最早心室前向激动点且有小A波处为消融靶点。房颤时成功消融靶点的V波较体表心电图预激波的起点提前 37.2± 8.1( 2 6～ 5 3)ms。放电 6± 3( 1～ 16 )次后 ,2 6例中有2 5例 ( 96 % )旁道前传被阻断 ,1例失败。阻断旁道前传后 30min ,3例自行恢复窦性心律 ,2 2例经直流电复律后恢复窦性心律 ,心室起搏示 2 5例中有 2 3例旁道逆传已被阻断 ,2例仍存在 ,经继续消融获得成功。随访 19.2± 11.7( 1～ 38)个月 ,除 1例复发正向前传型房室折返性心动过速 (O AVRT) ,经再次消融旁道逆传成功外 ,其他患者无O AVRT发作及旁道前传恢复的证据。结论 :心房颤动时射频消融显性房室旁道方法可行、成功率高     

Retrograde Supernormal Conduction in Concealed Accessory Atrioventricular Pathway Following Catheter Ablation

Supernormal Conduction in Concealed Kent Following Ablation. A case is presented of a 63-year-old woman with a concealed accessory pathway that exhibited retrograde supernormal conduction after radiofrequency catheter ablation. Although ventricular pacing at a slow rate revealed no retrograde conduction over the accessory pathway following ablation, the tachycardia recurred 15 months later. During ventricular pacing there was retrograde 1:1 conduction over the accessory pathway at a fast rate while there was intermittent VA dissociation with rare retrograde conduction at the slower rate. Ventricular extrastimulus testing demonstrated a supernormal conduction zone of the coupling interval. Thus, accessory pathways may exhibit supernormal conduction after catheter ablation. Pacing should be performed at both slow and fast rates to confirm the presence of conduction block following ablation.     

Catheter ablation of septal accessory conduction pathways with high frequency electric current]

In 58 symptomatic patients with septal accessory atrioventricular pathways, attempts at catheter ablation of the pathway were made using 500-kHz radiofrequency current. The methodological approach (introduction and final positioning of the ablation catheter) was dependent on the anatomical site of the accessory pathway. Right anteroseptal pathways were accessed via a jugular venous route, whereas a femoral venous route was used for right mid- and posteroseptal pathways. In these pathways, ablation was attempted from an atrial catheter position. Left posteroseptal pathways were located via mapping of the coronary sinus and were ablated either from the left ventricle or (in 3 cases) from the vena cordis media. Utilizing a deflectable catheter with a 4-mm tip electrode, ablation attempts were successful in 54 patients (93%) with a median of 12 radiofrequency current pulses of an average 24.9 W of power and 23.2 s length. The mean duration of the sessions was 4.6 h. Impairment of physiological conduction (first-degree AV block) was observed in 1 patient; complete heart block was never induced. Recurrences after initially successful ablation necessitated a repeat session in 2 patients. One patient died 3 days after successful ablation of a posteroseptal accessory pathway. Septal accessory pathways may be ablated using radiofrequency current with an efficacy and safety comparable to free-wall accessory pathways and with good preservation of physiological AV node-His bundle conduction.     

Radiofrequency catheter ablation of septal accessory atrioventricular pathways.

OBJECTIVE--Septal accessory atrioventricular pathways are recognised as being more difficult to ablate than pathways in other locations. This paper describes an experience of 48 consecutive patients with septal accessory pathways who had catheter ablation with radiofrequency current. PATIENTS AND METHODS--There were 28 male and 20 female patients, mean (SD) age 35 (17). 43 patients had a single accessory pathway and 5 patients had multiple accessory pathways. Pre-excitation was present in 37 patients, and 11 patients had concealed accessory pathways. 21 patients had had a previous electrophysiological study. Catheter ablation was undertaken with radiofrequency current delivered by a standard unipolar technique or by delivery of current across the septum (the bipolar technique). RESULTS--The median total procedure time was 167 (83) minutes including a 30-40 minute observation period after the abolition of conduction by the accessory pathway. The median total fluoroscopic time was 56 (30) minutes. 42 (88%) out of 48 patients had successful ablation of the pathway during the first session. In the six patients in whom the procedure failed, five had a midseptal pathway and one had a right anteroseptal pathway. A second attempt at ablation was made in two patients and succeeded in both. In total, 49 accessory pathways were successfully ablated in 44 (92%) out of 48 patients. The bipolar technique was used in 11 patients and succeeded in 10 patients. Standard unipolar current delivery had previously failed in seven of the 11 patients. Complications developed in two patients with a mid septal pathway (one with complete atrioventricular block and the other with a small pericardial effusion). CONCLUSION--Radiofrequency catheter ablation of septal accessory pathways is efficacious and safe. The procedure time can be shortened and success rate can be increased after improvement of the technique--that is, consideration of a bipolar approach for energy delivery in difficult cases.     

Electrophysiologic characteristics,electropharmacologic responses and radiofrequency ablation in patients with decremental accessory pathway

Objectives. This study sought to characterize the functional properties of decremental accessory atrioventricular (AV) pathways and to investigate their pharmacologic responses.Background. Although decremental AV pathways associated with incessant reciprocating tachycardia have been studied extensively, information about the electrophysiologic characteristics and pharmacologic responses of anterograde and retrograde decremental AV pathways is limited.Methods. Of 759 consecutive patients with accessory pathway-mediated tachyarrhythmia, 74 with decremental AV pathways were investigated (mean age 43 ± 18 years). After baseline electrophysiologic study, the serial drugs adenosine, verapamil and procainamide were tested during atrial and ventricular pacing. Finally, radiofrequency catheter ablation was performed.Results. Five patients had anterograde decremental conduction over the accessory pathway but had no retrograde conduction. Of the 64 patients with retrograde decremental conduction over the accessory pathway, anterograde conduction over the pathway was absent in 41 (64%), intermittent in 5 (8%) and nondecremental in 18 (28%). In the remaining five patients, anterograde and retrograde decremental conduction over the same pathway was found. The anterograde and retrograde conduction properties and extent of decrement did not differ between anterograde and retrograde decremental pathways. Posteroseptal pathways had the highest incidences of anterograde and retrograde decremental conduction. Intravenous adenosine, procainamide and verapamil caused conduction delay or block, or both, in 10 of 10, 10 of 10 and 4 of 10 of the anterograde and 20 of 20, 20 of 20 and 8 of 20 of the retrograde decremental pathways, respectively. All patients had successful ablation of the decremental pathways without complications. During the follow-up period of 31 ± 19 months, only one patient experienced recurrence.Conclusions. Decremental accessory pathways usually had functionally distinct conduction characteristics in the anterograde and retrograde directions. Their pharmacologic responses suggested the heterogeneous mechanisms of decremental conduction.     

The catheter ablation of accessory atrioventricular pathways using a radiofrequency]

Sixteen consecutive patients (5 males and 11 females) aged 40 +/- 22 years suffering for spontaneous symptomatic arrhythmias underwent attempted transcatheter ablation of an atrioventricular accessory pathway using radiofrequency current. Five patients had the WPW syndrome. The Kent bundle was located in the left free wall in 14 patients, in the right anteroseptal region in one patient and in the posteroseptal zone in one patient. A 7F catheter (Polaris, Mansfield) with a 4 mm2 distal electrode, was used for ablation positioned on the left atrioventricular annulus in the 13 patients with left free wall accessory pathways or at the right atrium in the two patients with right accessory pathways. Without general anesthesia, a mean of 12 +/- 9 applications of radiofrequency current were delivered between the large tip electrode and a large skin patch positioned on the left posterior chest. By using radiofrequency current, a successful clinical outcome was achieved in 14 of 16 patients (87%). In patients with concealed accessory pathways, accessory conduction was abolished in 10 of 11 patients, in 8 patients in the first radiofrequency session and in two other patients in a successful second procedure. In the 5 patients with the WPW syndrome, the anterograde conduction disappeared after the procedure but the retrograde conduction remained, although deteriorated, in 2 patients. One patient developed uncomplicated tibioperoneal thrombophlebitis and in 2 cases an elevated concentration of creatine kinase value was found. In one female patient with a concealed accessory pathway, the Kent bundle conduction reappeared 3 months after the procedure and was ablated in a second session.(ABSTRACT TRUNCATED AT 250 WORDS)     

下位法射频消融慢径路改良房室结治疗室上性心动过速23例

用下位法射频消融慢径路改良房室结治疗房室结折返性心动过速(AVNRT)18例,房室折返性心动过速(AVRT)5例.AVNRT中16例为慢—快型,1例快—慢型,1例慢—快型与快—慢型并存,18例慢径路全部阻断成功.AVRT中1例显性预激,4例隐性预激,有5例慢径路和3例房室旁路消融成功.射频放电时21例出现结性心律.无严重并发症出现.AVNRT病人中随仿1—15个月有1例复发,第二次射频成功.认为下位法射频消融阻断慢径路成功率高,并发症少.     

A permanent junctional reciprocating tachycardia with an atypically located accessory pathway successfully ablated from within the middle cardiac vein

Permanent form of junctional reciprocating tachycardia (PJRT) is an uncommon form of atrioventricular re-entrant tachycardia due to an accessory pathway characterized by slow and decremental retrograde conduction. The majority of accessory pathways in PJRT are localized in the posteroseptal zone. Despite the high success rate, failure may occur during endocardial radiofrequency catheter ablation due to epicardial insertion of the accessory pathway. We report a case of PJRT in a 25-year-old man in whom the accessory pathway was located epicardially in the posteroinferior region and ablated from within the middle cardiac vein by radiofrequency catheter ablation.     

Use of adenosine-sensitive nondecremental accessory pathways in assessing the results of radiofrequency catheter ablation

Adenosine can cause conduction block in about 20% of nondecremental accessory pathways. Along with atrial activation mapping, adenosine may help differentiate retrograde AV node conduction versus residual accessory pathway conduction after radiofrequency catheter ablation; however, it is important to test the accessory pathway response to adenosine before ablation, particularly with a concealed accessory pathway.     

Successful sequential radiofrequency catheter ablation of anatomically discrete antegrade and retrograde accessory pathway conduction in the Wolff-Parkinson-White syndrome.

Histopathologically, accessory atrioventricular (AV) pathways comprise tiny strands of working myocardium that traverse the AV groove and link between the atrial and ventricular myocardium. Antegrade and retrograde conduction in bidirectional accessory pathways have generally been considered to occur along the same fibers. This report details the successful catheter ablation of a left free wall accessory pathway with radiofrequency energy. Antegrade and retrograde conduction of the pathway were abolished sequentially by separate episodes of energy delivered at anatomically discrete though closely adjacent sites along the mitral annulus. This finding raises the interesting possibility of anatomic "compartmentalization" of antegrade and retrograde conduction along an accessory pathway.     

Site of Accessory Pathway Block After Radiofrequency Catheter Ablation in Patients with the Wolff-Parkinson-White Syndrome

Site of Accessory Pathway Block. Introduction: Recent studies have demonstrated that the most common site of accessory pathway conduction block following the introduction of a premature atrial stimulus during atrial pacing is between the accessory pathway potential and the ventricular electrogram. consistent with block at the ventricular insertion of the accessory pathway. However, no prior study has evaluated the site of conduction block during radiofrequency catheter ablation procedures. Therefore, the objective of this study was to determine the site of conduction block after catheter ablation of accessory pathways by analyzing and comparing the local electrograms recorded before and after radiofrequency energy delivery at successful ablation sites. Methods and Results: The electrograms evaluated in this study were obtained from 85 consecutive patients who underwent successful radiofrequency catheter ablation of a manifest accessory pathway. The 50 left free-wall accessory pathways were ablated using a ventricular approach and the 35 right free-wall or posteroseptal accessory pathways were ablated using an atrial approach. The characteristics of local electrograms recorded immediately before and immediately after successful ablation of the accessory pathway were determined in each patient. The site of accessory pathway block was determined by comparing the amplitude, timing, and morphology of the local eleclrograms at successful sites of radiofrequency catheter ablation before and after delivery of radiofrequency energy. A putative accessory pathway potential was present at the successful target site in 74 of the 85 patients (87%). Conduction block occurred between the atrial electrogram and the accessory pathway potential in 66 patients (78%) and between the accessory pathway potential and the ventricular electrogram in eight patients (9%). The site of block could not be determined in 11 patients (13%) in whom an accessory pathway potential was absent. Conduction block occurred most frequently between the atrial electrogram and the accessory pathway potential regardless of accessory pathway location. No electrogram parameter or accessory pathway characteristic was predictive of the site of conduction block. Conclusion: The results of this study demonstrate that conduction block occurs most frequently between the local atrial electrogram and the accessory pathway potential during radiofrequency catheter ablation of accessory pathways. This is true regardless of whether the accessory pathway is ablated from the atrial or ventricular aspect of the mitral or tricuspid annulus.