房室结双径路消融中特殊电生理现象分析与处理

目的：分析房室结折返性心动过速（AVNRT）慢径路消融中特殊电生理现象及处理体会。方法：慢径路消融前常规行心内电生理检查。结果：有特殊电生理现象者8例，其中3例患者AVNRT开始时表现为房室2：1传导，阻滞点在希氏束以上部位；3例患者房室结功能曲线呈连续性；1例为慢-慢型AVNRT；1例心内电生理检查未能诱发出AVNRT。所有患者慢径消融均成功，结论：术前应行详细的心内电生理检查和仔细鉴别，其消融方法与典型AVNRT相同。     

射频消融治疗房室结双径路的迟发效应1例

报道1例房室结双径路合并室上性心动过速 (SVT)患者射频消融手术失败后发生迟发效应而成功的病例. 患者,女性,42岁,反复发作SVT 10年.食管电生理检查诊断为房室结折返性心动过速(AVNRT),行心内电生理检查及射频消融术.心内电生理检查过程中,导管操作、分级递增刺激及程序刺激均可诱发SVT .并可见A-H跳跃、His递减传导等房室结传导特征,确诊为AVNRT.后位法行慢径消融,以时间滴定法共放电11次,其间有多次交界区心律出现,后因仪器故障中断手术,术毕时,程序刺激仍可诱发SVT.3天后再次手术时,电生理检查:170次/min心房刺激房室呈文氏传导,心室刺激、异丙肾上腺素刺激后再次行心房、心室刺激均未诱发室上速,无A-H跳跃.     

RFCA AVN双径路慢径改良对AVN前传动的影响

临床电生理学认为,房室结折返性心动过速(AVNRT)的电生理基础是房室结(AVN)双径路,但目前有关AVN前传特性及其传导曲线发生不连续性的机制了解还很有限。本文拟从射频消融术(RFCA)消融慢径前后AVN前传功能的变化探讨AVN双径路的电生理特性及双径路之间可能的相互作用。 1 资料与方法 1.1 病例选择 选择单纯房室结双径路(AVNDP)并AVNRT而成功行慢径射频消融的患者共54例,其中男17例,女37例;年龄13～73岁,平均45.3±13.2岁;心动过速发生时间为9.53±11.3年,均不合并其他器质性心脏病。     

房室结三径路食管心房调搏诱发房室结折近性心动过速

房室结三径路伴房室结折返性心动过速(AVNRT)的临床报道不多见。如果每条经路都能双向传导,理论上三径路者可有6种类型的AV-—RT,而实际发生的大多为慢快型。本文分析15例房室结三径路,食管心房调搏诱发AVNRT的机制及电生理特点。 1 资料和方法 对象为10余年来因心悸及快速心律失常而行食管电生理检查诊断为房室结三径路者,检查前停用各种抗心律失常药5个半衰期以上。按常规食管电生理检查方法进行,如果S_1S_2或S_1S_2S_3法不能显示三径路或诱发AVNRT,则给阿托品2mg静注后再重复以上检查。     

几种特殊慢-快型房室结折返性心动过速的射频消融

房室结折返性心动过速 (AVNRT)是常见的室上性心动过速 (SVT)约占 PSVT40 %～ 5 0 % ,其解剖和生理基础是心房肌与房室结之间移行细胞区各向异性传导 ,形成房室结双径路 (DAVNP) ,消除 DAVNP中任何一条均可阻断房室结内折返环 ,达到根治目的 [1 ]。目前用导管射频电消融 (RFCA)阻断慢径传导治疗典型 AVNRT的方法已经成熟 ,但是对一些特殊情况下的 AVNRT进行 RFCA尚缺乏经验 ,本文对几种特殊慢 -快型 AVNRT的慢径消融作一概述。1　几种特殊类型慢 -快型 AVNRT的特点及消融方法1.1　长 PR的 AVNRT　 DAVNP中少部分患…     

特殊类型房室结折返性心动过速的射频消融策略

目的：探讨特殊类型的房室结折返性心动过速（AVNRT）治疗方案。方法：我院1998年1月至2006年6月经射频消融治疗的AVNRT患者326例，回顾性分析其电生理特点及射频消融策略。结果：326例中323例消融成功，有9例复发，其中7例复发者均为保留慢径前传以不再诱发AVNRT为消融终点；3例失败者，1例发生Ⅲ度房室传导阻滞，2例为快-慢型AVNRT。结论：AVNRT的消融终点以阻断慢径传导为最佳，特殊病例需特殊处理。     

慢径消融治疗不能诱发的房室结折返性心动过速的远期疗效

目的:探讨有阵发性室上性心动过速(paroxysmal supravrentricular tachycardia,PSVT)病史和房室结双径路,但程序刺激不能诱发房室结折返性心动过速(atrioventricular nodal reentrant tachycardia,AVNRT)患者,进行慢径射频消融治疗的远期疗效。方法:在436例PSVT行慢径路消融治疗的患者中,49例程序刺激不能诱发AVNRT(A组),选择年龄、性别相匹配的、且程序刺激可诱发AVNRT的患者49例作为对照(B组)。比较两组患者快、慢径路的电生理特性及慢径路消融后的远期疗效。结果:①两组患者快、慢径路的电生理特性无明显差异;②所有患者均成功消除慢径路;③平均随访38．5±5个月,无一例PSVT复发。结论:对存在房室结双径路和典型PSVT病史,但程序刺激不能诱发AVNRT发作的患者,慢经路消融具有肯定的远期疗效。     

房室折返性心动过速合并房室结双径路的射频消融治疗

目的:探讨房室折返性心动过速(AVRT)合并房室结双径路(AVNDP)的电生理特征和射频消融术式的选择。方法:对640例阵发性室上性心动过速(PSVT)进行电生理检查,观察PSVT发作时传导的顺序,然后进行消融治疗。结果:640例PSVT中检出AVRT AVNDP 68例,检出率为10.6%;有8例诱发房室结折返性心动过速,对此类患者进行慢径消融治疗。随访所有经治患者均无复发。结论:AVRT合并AVNDP者阻断房室旁道是消融成功的关键;房室旁道作为"旁观者"时也应作房室旁道消融;如仅有(AH)跳跃但无心动过速者无需接受房室结改良。     

冠状窦口射频消融治疗房室结折返性心动过速15例分析

房室结、心房和移行细胞共同构成的大折返是临床上房室结折返性心动过速(AVNRT)的主要原因。而冠状窦口区的移行细胞也构成了房室结慢径路的一部分。近年来我们在冠状窦口周围进行射频消融,阻断从冠状窦区进入房室结慢径路的平行纤维,从而根治AVNRT,15例均取得成功。消融靶点10例在冠状窦口上方,2例在冠状窦口,2例在冠状窦口下方,1例在冠状窦口后方。平均放电次数3±1(1～5)次/min,放电功率18±5(10～28)W,平均每次放电时间36±15(40～60)s。消融后,A-H跳跃现象均消失,心房回波消失,不能再引出AVNRT。     

阵发性房室结折返性心动过速患者慢径路消融治疗的临床分析

目的探讨射频消融慢径路治疗阵发性房室结折返性心动过速（AVNRT）的临床效果。方法回顾性分析425例采用射频消融治疗的AVNRT患者的临床资料。结果417例手术成功，成功率98．12％。4例（0．94％）出现高度房宣传导阻滞，2例（0．47％）因心室率较慢而安装永久性起搏器。随访6个月内有8例复发，复发率1．9％。结论选择性慢径路消融是成功治愈AVNRT安全有效的方法。     

Acute and long-term results of slow pathway ablation in patients with atrioventricular nodal reentrant tachycardia--an analysis of the predictive factors for arrhythmia recurrence

BACKGROUND: Predictors of atrioventricular nodal reentrant tachycardia (AVNRT) recurrence after radiofrequency ablation including the importance of residual slow pathway conduction are not known. The aim of this study was to report the acute and long-term results of slow pathway ablation in a large series of consecutive patients with AVNRT and to analyze the potential predictors of arrhythmia recurrence with a particular emphasis on the residual slow pathway conduction after ablation. METHODS: The study included 506 consecutive patients with AVNRT (mean age 52.6 +/- 16 years, 315 women) who underwent slow pathway ablation using a combined electrophysiological and anatomical approach. The end point of ablation procedure was noninducibility of the arrhythmia. The primary end point of the study was the recurrence of AVNRT. RESULTS: Acute success was achieved in 500 patients (98.8%). After ablation, 471 patients (93%) were followed up for a mean of 903 +/- 692 days. Of the 465 patients with successful ablation, 24 patients (5.2%) developed AVNRT recurrences during the follow-up. No significant differences in the cumulative rates of AVNRT recurrence were observed in groups with or without electrophysiological evidence of residual slow pathway conduction (P = 0.25, log-rank test). Multivariate analysis identified only age as an independent predictor of AVNRT recurrence (hazard ratio 0.96, 95% confidence interval 0.94-0.99, P = 0.004) with younger patients being at an increased risk for arrhythmia recurrence. CONCLUSIONS: Our study demonstrated that only younger age, but not other clinical or electrophysiological parameters including residual slow pathway conduction predicted an increased risk for AVNRT recurrence after slow pathway radiofrequency ablation.     

The different ablation effects on atrioventricular nodal reentrant tachycardia in children with and without dual nodal pathways

BACKGROUND: Previous studies in adults have shown a significant shortening of the fast pathway effective refractory period (ERP) after successful slow pathway ablation. However, information on atrioventricular nodal reentrant tachycardia (AVNRT) in children is limited. The purpose of this retrospective study was to investigate the different effects of radiofrequency (RF) catheter ablation in pediatric AVNRT patients between those with and without dual atrioventricular (AV) nodal pathways. METHODS: From January 1992 to August 2004, a total 67 pediatric patients with AVNRT underwent an electrophysiologic study and RF catheter ablation at our institution. We compared the electrophysiologic characteristics between those obtained before and after ablation in the children with AVNRT with and without dual AV nodal pathways. RESULTS: Dual AV nodal pathways were found in 37 (55%) of 67 children, including 36 (54%) with antegrade and 10 (15%) with retrograde dual AV nodal pathways. The antegrade and retrograde fast pathway ERPs in children with dual AV nodal pathways were both longer than the antegrade and retrograde ERPs in children without dual AV nodal pathways (300 +/- 68 vs 264 +/- 58 ms, P = 0.004; 415 +/- 70 vs 250 +/- 45 ms, P < 0.001) before ablation. In children with antegrade dual AV nodal pathways, the antegrade fast pathway ERP decreased from 300 +/- 68 ms to 258 +/- 62 ms (P = 0.008). The retrograde fast pathway ERP also decreased after successful ablation in the children with retrograde dual AV nodal pathways (415 +/- 70 vs. 358 +/- 72 ms, P = 0.026). CONCLUSION: The dual AV nodal physiology could not be commonly demonstrated in pediatric patients with inducible AVNRT. After a successful slow pathway ablation, the fast pathway ERP shortened significantly in the children with dual AV nodal pathways.     

Radiofrequency catheter ablation therapy of swallowing-induced atrioventricular nodal reentrant tachycardia: report of two cases

We describe two patients who presented with a history of recurrent palpitations on swallowing of solid food. The event-recorder and Holter monitoring documented episodic supraventricular tachycardia (SVT) initiated by atrial premature contractions (APCs). During electrophysiological study (EPS), swallowing of solid food consistently induced APCs and their activation sequence, morphology of P wave were suggestive of their right atrial origin in them. Drug challenge did not affect the APC onset during the swallowing. During EPS, slow-fast variety of atrioventricular nodal reentrant tachycardia (AVNRT) was induced and successful radiofrequency (RF) catheter ablation of slow pathway resulted in total relief of their symptoms.     

Radiofrequency ablation of probable atrioventricular nodal reentrant tachycardia in children with documented supraventricular tachycardia without inducible tachycardia

The reproducible induction of supraventricular tachycardia (SVT) during electrophysiological study is critical for the diagnosis of atrioventricular nodal reentry tachycardia (AVNRT), and for determining a therapeutic endpoint for catheter ablation. In the sedated state, there are patients with reentry SVT due to AVNRT who are not inducible at electrophysiological study. This article reports on the empiric slow pathway modification for AVNRT in six pediatric patients (age 6-17, mean 13.3 years) with documented, recurrent, paroxysmal SVT in the setting of a structurally normal heart who were not inducible at electrophysiological study. Atrial and ventricular burst and extrastimulus pacing at multiple drive cycle lengths were performed in the baseline state, during an isuprel infusion, and during isuprel elimination. Single AV nodal (AVN) echo beats were present in all patients, while classic dual AVN physiology was present in three of six patients. Radiofrequency energy was administered in the right posteroseptal AV groove resulting in accelerated junctional rhythm in five of six patients. Postablation testing demonstrated the elimination of echo beats in four patients, while dual AVN physiology and echo beats persisted in two patients. At follow-up (22-49 months, mean 29.5 months), all patients are asymptomatic without recurrence of SVT and are not taking any antiarrhythmic medication. In selected patients, empiric slow pathway modification may be offered as a potential cure in children with recurrent paroxysmal SVT who are not inducible at electrophysiological study. Elimination of slow pathway conduction may serve as a surrogate endpoint, though is not necessary for long-term success.     

Meta-analysis to assess the appropriate endpoint for slow pathway ablation of atrioventricular nodal reentrant tachycardia

Background: There are little data on the appropriate endpoint for slow pathway ablation that balances acceptable procedural times, recurrence rates, and complication rates. This study compared recurrence rates of three commonly utilized endpoints of slow pathway ablation for atrioventricular nodal reentrant tachycardia (AVNRT). Methods: We performed a meta‐analysis of AVNRT slow pathway ablation cohorts by searching electronic databases, the Internet, and conference proceedings. Inclusion criteria were age >18 years, >20 human subjects per study, primary AVNRT ablation, English language publication, and >1 month of follow‐up. Data were analyzed with a fixed‐effects model using Comprehensive Meta‐Analysis software version 2.2.046 (Biostat, Englewood, NJ, USA). Results: We included 10 studies encompassing 1,204 patients with a mean age of 41–53 years. Endpoints were complete slow pathway ablation, residual jump only, and single remaining echo beat. Pooled estimates revealed 28 of 641 patients (4.4%) with complete slow pathway ablation, 13 of 192 patients (6.8%) with a residual jump only, and 24 of 371 patients (6.5%) with one echo had recurrences. With uniform isoproterenol use after ablation, there was no significant difference in recurrence rates among the endpoints. However, when isoproterenol was utilized after ablation only if needed to induce AVNRT before ablation, a significantly higher recurrence rate occurred in patients with a residual jump (P = 0.002), a single echo (P = 0.003), or the combined group of a residual jump and/or one echo (P = 0.001). Conclusions: Isoproterenol should be used routinely after slow pathway modification, when a residual jump and/or single echo remain. (PACE 2011; 34:269–277)     

Atrioventricular nodal reentry tachycardia: slow pathway ablation using the transseptal approach

Four hundred twenty consecutive patients with symptomatic slow/fast atrioventricular nodal reentry tachycardia had attempted slow pathway radiofrequency ablation. All patients had successful slow pathway ablation and no inducible tachycardia after ablation using the standard right-sided approach except for three patients. The three unsuccessful patients had inducible slow/fast atrioventricular nodal tachycardia after attempted right-sided posterior and inferoposterior anatomic ablative techniques and with slow pathway potential electrogram guidance. Lesions were also delivered linearly in the triangle of Koch and within the coronary sinus ostium. A transseptal puncture was performed and slow pathway ablation was obtained in each of these patients. Ablation was performed from the septal mitral valve annulus, anterior to the os of the coronary sinus and inferior to the His-bundle catheter with elimination of slow pathway conduction. Prior to the ablation, two of the three patients exhibited initiation of tachycardia with a double fast/slow antegrade response, and all three patients had long AH intervals (mean 378 ms) during slow pathway conduction. These electrophysiological findings may be consistent with a large area of slow pathway conduction that may include the left atrial septum not approachable by conventional right-sided ablative techniques. Slow pathway ablation to eliminate atrioventricular nodal reentry tachycardia at times may require a left atrial/transseptal approach when conventional right-sided techniques are ineffective.     

Sustained Slow Pathway Conduction: Superior to Dual Atrioventricular Node Physiology in Young Patients with Atrioventricular Nodal Reentry Tachycardia?

BACKGROUND: Young patients with atrioventricular nodal reentry tachycardia (AVNRT) frequently do not display discrete dual AV node physiology (DAVNP) as classically defined. The purpose of the study was to investigate the prevalence of sustained slow pathway conduction (SSPC; PR > RR during atrial pacing) in young patients with AVNRT and compare it to dual atrioventricular node physiology. METHODS: The presence of SSPC and DAVNP was prospectively assessed before and after radiofrequency catheter ablation in 61 young patients (age 4-23 years) with typical AVNRT. RESULTS: Prior to ablation, 32 (52%) displayed DAVNP, while 46 (75%) displayed SSPC; 7 patients (11%) had neither marker. Patients with DAVNP were older than those without (15 +/- 3 vs 13 +/- 4, P = 0.027) and the prevalence increased with age (38% <13 years, 50% 13-15, 70% >15, P = 0.041), while SSPC showed no age predilection. Patients under 13 years displayed SSPC more commonly than DAVNP (81% vs 38%, P = 0.004). DAVNP persisted after ablation in 10/32 (31%) patients, compared to 6/46 (13%) with persistent SSPC after ablation. The ability to use loss of the marker (present before, absent after ablation) as a surrogate for successful ablation was greater for SSPC than for DAVNP (66% vs 36%, P = 0.001). CONCLUSION: SSPC is more common than DAVNP in young patients with AVNRT. SSPC is eliminated more frequently than DAVNP after acutely successful ablation, and appears to be a better indicator of the substrate for AVNRT. Elimination of SSPC may serve as a useful surrogate endpoint for slow pathway ablation.     

Determination of Repetitive Slow Pathway Conduction for Evaluation of the Efficacy of Radiofrequency Ablation in AVNRT

LUKAC, P., et al.: Determination of Repetitive Slow Pathway Conduction for Evaluation of the Efficacy of Radiofrequency Ablation in AVNRT. Aims: To determine whether the loss of repetitive slow pathway conduction identifies a successful radiofrequency ablation of atrioventricular nodal reentry tachycardia (AVNRT). Methods and results: Thirty nine consecutive patients undergoing ablation of AVNRT using the slow pathway approach were included. At baseline and after each radiofrequency application with an episode of junctional rhythm, repetitive slow pathway conduction was assessed as follows: Effective refractory period of the fast pathway was determined. The coupling interval of the first atrial extrastimulus (A2) was set at 30 ms below the effective refractory period of the fast pathway to ensure its conduction via the slow pathway. The second atrial extrastimulus (A3) was introduced at progressively longer coupling intervals starting from 200 ms until: (1) it propagated to the His bundle or (2) an anterogradely blocked AV nodal echo of A2 appeared before a conducted A3 depolarized the atrium in the His bundle electrogram. The response was termed repetitive slow pathway conduction if A3 was conducted with an   AH > 200 ms   . Application was considered successful if no AVNRT could be induced. Repetitive slow pathway conduction was present after 1 of 39 successful and after 34 of 40 ineffective applications   (P < 0.0001)   . Repetitive slow pathway conduction identified a successful application with 97% sensitivity, 86% specificity, 86% positive predictive value, and 97% negative predictive value. Conclusion: The presence of repetitive slow pathway conduction identifies an unsuccessful application with a clinically meaningful negative predictive value. (PACE 2003; 26[Pt. I]:827–835)     

Electrophysiology of inducible atrial flutter in patients with atrioventricular nodal reentrant tachycardia

An association between atrial flutter and atrioventricular nodal reentrant tachycardia (AVNRT) has been observed, but the underlying mechanisms are poorly defined. This issue was therefore investigated by comparing the electrophysiological properties of AVNRT patients with and without inducible atrial flutter and those of patients with a history of flutter. Twenty-nine patients with clinically documented atrial flutter and 104 with AVNRT were studied. Atrial flutter was induced in 38 (37%) AVNRT patients during standardized electrophysiological testing before radiofrequency ablation. The atrial relative refractory periods in AVNRT patients with inducible flutter (260 +/- 30 ms) were significantly shorter than those of either patients with a history of flutter (282 +/- 30 ms; P = 0.02) or AVNRT patients without inducible flutter (284 +/- 38 ms; P = 0.006). The atrial effective refractory periods in AVNRT patients with inducible flutter (205 +/- 31 ms) were shorter than in AVNRT patients without inducible flutter (227 +/- 40 ms; P = 0.01). The maximum AH interval during premature atrial stimulation in patients with clinical flutter (239 +/- 94 ms) was shorter than in AVNRT patients either with (290 +/- 91 ms; P = 0.04) or without inducible flutter (313 +/- 101 ms; P = 0.002). However, no significant differences were found in the maximum AH interval achieved during incremental atrial pacing among different groups. Our data show that a non-clinical flutter could more often be induced in those who had short atrial refractoriness. Despite their anatomical proximity, the slow pathway conduction of AVNRT and the isthmus slow conduction of flutter may be related to different mechanisms.