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)     

房室结折返性心动过速慢径路消融过程中交界心律的电生理特征

目的:分析房室结折返性心动过速行慢径路消融过程中,出现交界心律时心房激动特征以及希氏束波到高位右心房的传导时间.方法:行慢径路消融的房室结折返性心动过速患者100例,分别测量心动过速时希氏束波到高位右心房的传导时问(HAT),以及交界心律出现时希氏束波到高位右心房的传导时间(HAJ).结果:在慢快型和慢中型折返性心动过速慢径路消融过程中,交界心律出现时逆传心房激动顺序与心动过速相比仅有微小的变化.交界性心律时逆传HA间期短于心动过速时的HA间期(P<0.05),在快慢型折返性心动过速慢径路消融过程中,交界心律出现时没有逆传心房激动.结论:在慢快型和慢中型折返性心动过速慢径路消融过程中,交界心律通过快径路和中间径路逆传;在快慢型折返性心动过速慢径路消融过程中,交界心律逆传阻滞.     

Tachycardiomyopathy secondary to nonreentrant atrioventricular nodal tachycardia: recovery after slow pathway ablation

Nonreentrant atrioventricular (AV) nodal tachycardia is a rare form of arrhythmia due to simultaneous anterograde conduction in dual AV pathways, one atrial impulse triggering two ventricular complexes. We report the case of a 74-year-old man referred for incessant palpitations resistant to antiarrhythmic medication, and effort dyspnea. A nonreentrant AV nodal tachycardia is diagnosed with electrophysiological study. A dilated cardiomyopathy with left ventricular dysfunction is found with gated blood pool single-photon emission computed tomography. A radiofrequency catheter ablation of the slow pathway is successfully performed. The patient is reassessed 11 months after ablation. He is asymptomatic and left ventricular function has fully recovered.     

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。     

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.     

不同亚型房室结折返性心动过速电生理学特点与射频消融

目的 从不同亚型房室结折返性心动过速电生理学特性及射频消融前后房室结快径前传不应期差异.探讨其电生理学机制.方法 178例慢快型房室结折返性心动过速患者中按消融完成顺序取连续30例,与慢慢型11例和快慢型8例,比较AH跳跃、心动过速时HA、△VA等电生理参数差异,以及射频消融术前后房室结快径前传不应期改变.结果 慢慢型患者AH跳跃明显小于慢快型及快慢型,HA、△VA介于后两型之间;慢快型及快慢型消融术后快径前传不应期显著缩短,慢慢型则有轻度延长趋势.结论 慢慢型房室结折返性心动过速电生理特性明显不同于慢快型及快慢型,消融前传慢径后房室结快径前传不应期未相应缩短,支持其折返环中尚存在逆传慢径.     

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.     

Electrophysiological markers predicting impeding AV‐block during ablation of atrioventricular nodal reentry tachycardia

1 Background

Radiofrequency (RF) ablation of the slow pathway (SP) in atrioventricular nodal reentry tachycardia (AVNRT) is occasionally complicated with atrioventricular block (AVB) often predicted by junctional beats (JB) with loss of ventriculo‐atrial (VA) conduction.

2 Methods

We analyzed retrospectively 153 patients undergoing ablation of SP for typical AVNRT. Patients were divided into two age groups: 127 ≤ 70 years and 26 > 70 years. We analyzed the interval between the atrial electrogram in the His‐bundle position and the distal ablation catheter [A(H)‐A(RFd)] and between the distal ablation catheter and the proximal coronary sinus catheter [A(RFd)‐A(CS)] before RF applications with and without JB. We evaluated if these intervals can be used as predictors of JB incidence and also of JB with loss of VA conduction. We also assessed if age influences the risk of loss of VA conduction.

3 Results

The A(H)‐A(RFd) and A(RFd)‐A(CS) intervals were significantly shorter in RF applications causing JB than those without JB (33 ± 11 ms vs 39 ± 9 ms, P < 0.001, 14 ± 9 ms vs 20 ± 7 ms, P < 0.001, respectively). The A(H)‐A(RFd) and A(RFd)‐A(CS) intervals were also significantly shorter in RFs causing JB with VA block than those with VA conduction (29 ± 11 ms vs 35 ± 11 ms, P < 0.001, 8 ± 8 ms vs 17 ± 8 ms, P < 0.001, respectively). Patients > 70 years had shorter intervals (36 ± 11 ms vs 29 ± 8 ms, P  =  0.012, 17 ± 8 ms vs 13 ± 7 ms, P  =  0.027, respectively), while VA block was more common in this age group.

4 Conclusions

The A(H)‐A(RFd) and A(RFd)‐A(CS) intervals can be used as markers for predicting JB occurrence as well as impending AVB. JB with loss of VA conduction occur more often in older patients possibly due to a higher position of SP.     

Successful radiofrequency ablation of a slow atrioventricular nodal pathway on the left posterior atrial septum

RF catheter ablation is highly effective in eliminating atrioventricular nodal reentrant tachycardia by targeting the slow pathway in the posteroinferior part of Koch's triangle in the right atrium. We report here a patient in whom "slow-fast" atrioventricular nodal reentrant tachycardia was eliminated only by ablation of the slow pathway in the left atrial posteroseptal region at the level of the mitral annulus after unsuccessful attempts at the traditional site on the right side.     

A specific sign for differential diagnosis of atypical atrioventricular nodal reentrant tachycardia from atrial tachycardia

Narrow QRS tachycardia with atrial activation occurring before ventricular activation was induced in a 34-year-old woman with dilated cardiomyopathy. During tachycardia late ventricular extrastimulus delivered when His bundle was refractory failed to reset the tachycardia while early ventricular extrastimulus caused paradoxical delay of the subsequent atrial response and terminated the tachycardia with a QRS not being followed by an atrial response. This is a rare but specific sign for excluding atrial reentry as the mechanism of tachycardia when P wave or atrial activation is registered before QRS response.     

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.     

Differential diagnosis of slow/slow atrioventricular nodal reentrant tachycardia from atrioventricular reentrant tachycardia using concealed posteroseptal accessory pathway by 12-lead electrocardiography

Slow pathways are used as both antegrade and retrograde conduction pathway in slow/slow atrioventricular nodal reentrant tachycardia (SS-AVNRT), and patients with SS-AVNRT have tachycardia ECGs mimicking atrioventricular reentrant tachycardia using concealed posteroseptal accessory pathway (PS-AVRT). Therefore, SS-AVNRT can be misdiagnosed as PS-AVRT, and the differential diagnosis is clinically important. Standard 12-lead ECGs during tachycardia were analyzed in patients with SS-AVNRT (n = 10) and PS-AVRT (n = 10). All these patients were diagnosed by electrophysiological study and underwent successful catheter ablation. Differences of the RP' intervals (dRP') between V1 and the inferior leads were evaluated. SS-AVNRT had significantly longer RP' intervals measured in V1 (167 +/- 25.2 vs 137 +/- 26.8 ms, SS-AVNRT vs PS-AVRT, respectively, P = 0.02), longer dRP' between V1 and II (dRP'[V1-II], 37 +/- 14 vs 17 +/- 6.7 ms, P = 0.0007), longer dRP'[V1-III] (39 +/- 14 vs 17 +/- 9.9 ms, P = 0.0011), and longer dRP'[V1-aVF] (39 +/- 13 vs 20 +/- 9.5 ms, P = 0.0008). The following criteria were suggested for differential diagnosis of SS-AVNRT from PS-AVRT: dRP'[V1-II] >25 ms (sensitivity and specificity: 80% and 100%, respectively), dRP'[V1-III] >23 ms (90% and 90%), dRP'[V1-aVF] >30 ms (90% and 90%). Differences of the RP' intervals between V1 and the inferior leads in the tachycardia ECGs were useful for differential diagnosis of SS-AVNRT from PS-AVRT.     

Slow junctional rhythm during catheter ablation of right posteroseptal accessory pathway causing transient atrioventricular block

A male patient with palpitations and syncope during an episode of atrial fibrillation was evaluated. After DC cardioversion, the ECG showed a pattern of pre-excitation compatible with right posteroseptal bypass tract. The patient was submitted to RF. During energy application a slow junctional rhythm without AV block was noted. Twenty-four hours after the procedure AV block was observed. The AV conduction was resumed spontaneously 48 hours later with unremarkable outcome up to 1 year. We postulated that the edema caused by RF application damaged the compact AV node, causing transient AV block. The AV node lesion has been manifested by a fast junctional rhythm, but in this case we observed that even a slow junctional rhythm could do it.     

Superior type of atypical AV nodal reentrant tachycardia: incidence, characteristics, and effect of slow pathway ablation

Background: Atypical atrioventricular (AV) nodal reentrant tachycardias (AVNRT) usually exhibit the earliest retrograde atrial activation (ERAA) at the right inferoseptum (Rt-IS) or proximal coronary sinus (PCS). The purpose of this study was to characterize atypical AVNRT with the ERAA at the right superoseptum (Rt-SS).
Methods: Seventy-three atypical AVNRTs induced in 63 cases were classified into the superior type with the ERAA at the Rt-SS and inferior type with the ERAA at the Rt-IS or PCS.
Results: There were nine superior (12%) and 64 inferior types of atypical AVNRT (88%) in seven and 56 cases, respectively. The superior type exhibited a short atrial-His interval during the tachycardia (166 ± 41 ms), long His-atrial interval during the tachycardia (H-At:156 ± 38 ms), and ventricular pacing at the tachycardia cycle length (TCL) (H-Ap:201 ± 36 ms), and evidence for a lower common pathway, including second-degree AV block (four tachycardias) and an H-Ap being longer than the H-At (nine tachycardias). The TCL was shorter in the superior type than in the inferior type (322 ± 35 vs 404 ± 110 ms; P < 0.02). In the inferior type, all tachycardias were eliminated after the ablation at the Rt-IS (44 tachycardias) or PCS (20 tachycardias) where an ERAA was recorded. In the superior type, ablation at the Rt-IS was ineffective; however, ablation at the right midseptum eliminated seven (78%) of the nine tachycardias.
Conclusions: The tachycardia circuit of the superior type might have deviated to a more superior part of Koch's triangle than that of the inferior type.     

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.     

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.     

Modification of antegrade slow pathway is not crucial for successful catheter ablation of common atrioventricular nodal reentrant tachycardia

We tested the hypothesis that in some patients affected by typical AVNRT, successful catheter ablation treatment may be achieved independently of specific measurable electrophysiological modifications of antegrade AV node conducting properties. Standard electrophysiological parameters and comparable antegrade AV node function curves were obtained, before and after successful ablation, in 104 patients (mean age 52 +/- 16 years; 69 women and 35 men) affected by the common form of AVNRT. The end point of the ablation procedure was noninducibility of AVNRT and of no more than one echo beat. For the purpose of this study, AV node duality was defined as an increase of > or = 50 ms in the A2H2 interval in response to a 10 ms decrease of the A1A2 coupling interval. Before ablation, AV node duality was present in 65 patients (62%) and absent in 39 patients (37%). Ablation caused measurable modifications of electrophysiological properties of the AV node in most patients with elicited AV node duality, but not in most patients without demonstrable AV node duality. After ablation, AV node duality persisted in 20 patients who had it before, whereas a new duality that could not be elicited before appeared in 5 patients. During 19 +/- 6 months of follow-up, clinical AVNRT recurred in 1 of 45 patients who had disappearance of AV node duality after ablation, in 1 of 34 patients who did not show AV node duality before and after ablation, and in 1 of 20 patients who had persistence of AV node duality after ablation. In conclusion, modifications of antegrade conduction properties of the AV node are not crucial for the cure of AVNRT in many patients.     

Relation between the AH interval and the ablation site in patients with atrioventricular nodal reentrant tachycardia

The determinants of slow pathway conduction in patients with AV nodal reentrant tachycardia (AVNRT) are still unknown, and great differences in the AH interval during slow pathway conduction are observed between patients. In 35 patients with typical AVNRT who underwent successful slow pathway ablation (defined as complete elimination of dual pathway physiology), the A2H2 interval at the "jump" during programmed atrial stimulation and the AH interval during AVNRT (as a reflection of slow pathway conduction time) and the fluoroscopic distance between the successful ablation site and the His-bundle recording site and between the coronary sinus ostium (CSO) and the His-bundle recording site were determined. The mean (+/- SEM) AH interval during slow pathway conduction was 323 +/- 12 ms with programmed stimulation and 310 +/- 10 ms during AVNRT. The mean number of energy applications was 8 +/- 1 (range 1-21). The mean distances between (1) the successful ablation site and the His bundle recording site and (2) between the CSO and the His-bundle recording site were 24 +/- 1 and 28 +/- 1 mm in the RAO and 23 +/- 1 and 28 +/- 1 mm in the LAO projections, respectively. The AH interval during slow pathway conduction correlated significantly with the distance between the successful ablation site and the His-bundle (P < 0.001) but not with the distance between CSO and His-bundle recording site. There is a significant correlation between the AH interval during slow pathway conduction and the distance of the successful ablation site from the His bundle. This relationship (1) suggests that, in addition to functional factors, anatomic factors influence slow pathway conduction and (2) may be helpful in determining the initial energy application site during slow pathway ablation.