Successful elimination of concealed accessory pathway-mediated tachycardia by ablation of AV nodal slow pathway

We report a case of atrioventricular reentrant tachycardia (AVRT) using a concealed para-Hisian accessory pathway for retrograde conduction, which also required anterograde conduction over the AV nodal slow pathway to maintain the tachycardia. The shortest VA interval during AVRT (70 ms) was noted at a site with His bundle electrogram amplitude of 0.25 mV. The AVRT was cured by radiofrequency ablation of the AV nodal slow pathway without affecting accessory pathway conduction. The patient has not reported any sustained palpitations at 2 years after ablation while receiving no medications. The case presented in this report illustrates a para-Hisian AVRT that was successfully eliminated by an unconventional approach of ablation of the atrial inputs to the AV nodal slow pathway.     

Radiofrequency ablation in two patients with typical and atypical atrioventricular nodal reentrant tachycardias, associated with atrioventricular reentrant tachycardias.

The incidence of dual atrioventricular nodal physiology in patients with Wolff-Parkinson-White syndrome is quite frequent, but arrhythmia related to an accessory pathway and atrioventricular nodal reentrant tachycardia (AVNRT) in a single patient is less common. Two of our cases (patients aged 24 and 19 yrs) presented the rare evidence of both typical and atypical AVNRTs, associated in the first case with two other atrioventricular reentrant tachycardias (AVRTs), and in the second case with a single AVRT. Both underwent radiofrequency catheter ablation of the slow nodal pathway and of the accessory pathways in a single session, without any complications. After a 3-month follow-up, they were free from symptoms suggestive of tachycardia, without any antiarrhythmic treatment.     

心房起搏时PR与RR间期比值对阵发性室上性心动过速鉴别诊断的意义

为探讨快速心房起搏最短１∶１房室传导时最大ＰＲ间期（ＰＲｍａｘ）与ＲＲ间期比值（ＰＲｍａｘ／ＲＲ）在鉴别阵发性室上性心动过速中的意义，分析比较了２０例房室结折返性心动过速（ＡＶＮＲＴ，有房室结前传跳跃现象者１２例、无跳跃现象者８例）和２０例房室折返性心动过速（ＡＶＲＴ）患者消融前、后快速心房起搏时最短１∶１房室传导的ＰＲｍａｘ／ＲＲ。ＡＶＮＲＴ组消融前、后心房快速起搏时最短１∶１房室传导的ＰＲｍａｘ／ＲＲ为１．１２±０．１２和０．４２±０．０７，两者比较差异有高度显著性，Ｐ＜０．０１；ＡＶＲＴ组为０．５２±０．１６和０．５１±０．１８，两者比较差异无显著性，Ｐ＞０．０５。消融前，ＡＶＮＲＴ组ＰＲｍａｘ／ＲＲ与ＡＶＲＴ组相比有显著性差异（１．１２±０．１２ｖｓ０．５２±０．１６，Ｐ＜０．０１）。ＰＲｍａｘ／ＲＲ＞１诊断ＡＶＮＲＴ的敏感性为９０％、特异性９１％。提示ＰＲｍａｘ／ＲＲ＞１在消融前可用来鉴别ＡＶＮＲＴ与ＡＶＲＴ；对无房室结前传跳跃的ＡＶＮＲＴ，消融后ＰＲｍａｘ／ＲＲ＜１可作为慢径消融成功的指标     

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.     

Interventionelle Therapie tachykarder Herzrhythmusstörungen bei Kindern

Over the past decades, interventional therapy of tachyarrhythmias in children without structural heart disease has evolved as an alternative to chronic pharmacological treatment. Catheter ablation in children over 5 years with symptomatic tachycardia using radiofrequency- or cryoenergy is nowadays performed with high success and low complication rates at experienced centers. The use of modern technologies such as non-fluoroscopic 3-dimensional mapping has further increased efficacy and safety of catheter ablation, and has led to a significant reduction of fluoroscopy time and dose. Arrhythmia substrates treated most frequently by catheter ablation in children include accessory pathways (WPW syndrome) leading to atrioventricular reentrant tachycardia (AVRT) and dual AV nodal pathways causing atrioventricular nodal reentrant tachycardia (AVNRT). Success rates of catheter ablation for these substrates during long-term follow up are over 90?%. Less common forms of tachycardias in children, such as focal atrial tachycardia, ventricular outflow tachycardias or idiopathic left ventricular tachycardia, are also amenable to catheter ablation with good long-term results. In asymptomatic children with preexcitation on the surface ECG (accessory pathway with the risk of rapid antegrade conduction during atrial fibrillation) the indication for catheter ablation of the accessory pathway for the prevention of sudden cardiac death should already be evaluated during childhood.     

His束逆传不应期心室早搏刺激鉴别间隔隐匿性旁道与房室结折返性心动过速

探讨His束逆传不应期心室早搏刺激法临床应用时的注意事项。 37例慢 快型房室结折返性心动过速(AVNRT)和 2 0例间隔部隐匿性快旁道引起的房室折返性心动过速 (AVRT)患者 ,成功消融前在常规行腔内电生理检查的同时均行His束逆传不应期心室早搏刺激法。结果 :心动过速时His束逆传不应期内心室早搏刺激 ,37例AVNRT患者心房激动无明显提前 ,2 0例AVRT心房被提前激动超过 2 0 (30～ 5 0 )ms ,其中 9例终止心动过速 ,此方法鉴别AVRT和AVNRT特异度、灵敏度较高。结论 :心动过速时His束逆传不应期行心室早搏刺激法鉴别诊断AVRT和AVNRT操作简单、准确性高。但行此法检查时要求有持续发作的心动过速 ;能够标测出清晰的His束电位 ;心室早搏刺激最好与His束电位同步发放 ;反复多次重复检测以进一步提高诊断的正确性     

食管心房调搏诊断室上性心动过速的临床研究

为探讨食管心房调搏揭示室上性心动过速发生机制的价值和局限性,回顾性分析成功射频导管消融的１３８例隐匿性单房室旁道参与的顺向型房室折返性心动过速和１００例单一类型房室结折返性心动过速的食管心房调搏结果。结果显示：前１３８例中,３例前间隔旁道引起者食管心房调搏均诊断为房室结折返性心动过速余为左右侧其它部位的旁道,诊断正确。后１００例中,５例为慢－慢型,２例为快－慢型,食管心房调搏均诊断为房室折返性心动     

Electrophysiological mechanisms of conversion of typical to atypical atrioventricular nodal reentrant tachycardia occurring after radiofrequency catheter ablation of the slow pathway

This report presents an adult patient with conversion of typical to atypical atrioventricular nodal reentrant tachycardia (AVNRT) after slow pathway ablation. Application of radiofrequency energy (3 times) in the posteroseptal region changed the pattern of the atrioventricular (AV) node conduction curve from discontinuous to continuous, but did not change the continuous retrograde conduction curve. After ablation of the slow pathway, atrial extrastimulation induced atypical AVNRT. During tachycardia, the earliest atrial activation site changed from the His bundle region to the coronary sinus ostium. One additional radiofrequency current applied 5 mm upward from the initial ablation site made atypical AVNRT noninducible. These findings suggest that the mechanism of atypical AVNRT after slow pathway ablation is antegrade fast pathway conduction along with retrograde conduction through another slow pathway connected with the ablated antegrade slow pathway at a distal site. The loss of concealed conduction over the antegrade slow pathway may play an important role in the initiation of atypical AVNRT after slow pathway ablation.     

Suppressive effect of SUN1165 on supraventricular tachycardia

The electrophysiologic properties of SUN1165 and its suppressive effect on supraventricular tachycardia were assessed in 14 patients, nine with atrioventricular reentrant tachycardia (AVRT) and five with atrioventricular nodal reentrant tachycardia (AVNRT). This new agent prolonged the PR interval and QRS duration but did not alter the QT interval or the corrected QT interval. It did not alter the sinus cycle length or sinus node recovery time. The drug prolonged the AH interval, HV interval, and intraatrial conduction time but did not change the effective refractory periods of the right atrium or right ventricle. SUN1165 prevented the induction of tachycardia in six of nine patients with AVRT by a complete retrograde block of the accessory pathway and prevented AVNRT in four of five patients by a complete retrograde block of the fast atrioventricular nodal pathway as well. We conclude that SUN1165 is very effective in preventing AVRT or AVNRT. Larger studies with more patients are warranted.     

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。     

U Wave during Supraventricular Tachycardia: Simulation of a Long RP Tachycardia and Hiding the Common Type AVNRT

The main tool for the differentiation of supraventricular tachycardia is the 12‐lead electrocardiogram (ECG). Especially differentiating the atrioventricular nodal reentrant tachycardia (AVNRT) from the atrioventricular reentrant tachycardia (AVRT) due to concealed accessory pathway or from an atrial tachycardia (AT) is very important for catheter setting and ablation approach in an electrophysiological study. In our case we saw the occurrence of a U wave during tachycardia—simulating a pseudo P wave. This mimicked a long RP‐tachycardia, although it was a common type AVNRT.     

室性心动过速合并室上性心动过速的射频消融

目的报道7例室性心动过速（VT）合并室上性心动过速（sVT）的射频消融。方法7例患者男6例,女1例,平均年龄（21±9）岁。阵发性心动过速病史（3．7±2．0）年。术中心房和心室刺激诱发VT和SVT,并进行消融。结果7例患者心房或心室刺激能反复诱发和终止VT合并SVT。法洛四联症矫治术后右心室VT合并三尖瓣环峡部依赖性心房扑动（AFL）1例,其余6例均为维拉帕米敏感性左心室特发性室速（ILVT）,分别合并AFL1例,左后间隔旁路参与的顺向型房室折返性心动过速（AVRT）1例,冠状静脉窦口慢旁路参与的顺向型AVRT1例,慢慢型房室结折返性心动过速（AVNRT）1例,左侧游离壁旁路参与的顺向型AVRT2例。7例患者的两种心动过速均成功消融,所有患者消融术后随访2年,无一例VT或SVT复发。结论VT合并SVT并不少见,消融术中应放置必需的心腔内电极导管,完成详细电生理检查,避免漏诊。一次消融应根除两种疾病。     

Simultaneous antegrade dual AV node conduction initiates AV nodal re-entrant tachycardia (a rare initiation mechanism)

Typical atrioventricular nodal reentrant tachycardia (AVNRT) is the most common paroxysmal supraventricular tachycardia among adults. The concept of dual pathway physiology remains widely accepted, although this physiology likely results from the functional properties of anisotropic tissue within the triangle of Koch, rather than anatomically distinct tracts of conduction. AVNRT is typically induced with anterograde block over the fast pathway and conduction over the slow pathway, with subsequent retrograde conduction over the fast pathway. On rare occasions, anterograde AV node conduction occurs simultaneously through fast and slow pathways resulting in two ventricular beats in response to one atrial beat. We report a case of AVNRT where the tachycardia is always induced by the same mechanism described above. Successful ablation was achieved by slow pathway modification.     

Multiple reentry tachycardia in patients with ventricular preexcitation: report of three cases

The electrophysiologic studies of three patients with accessory pathways and multiple reentrant circuits are reported. The first patient had two atrioventricular accessory pathways: a left posterior capable of bidirectional conduction and a right paraseptal with retrograde conduction only. Four atrioventricular reentry circuits were documented: left and right orthodromic circuits and a left antidromic circuit with retrograde conduction over the right paraseptal accessory pathway. The second patient had a left lateral atrioventricular accessory pathway with type A preexcitation. Two reentrant tachycardias were noted: an atrial tachycardia where the accessory pathway remained concealed and an orthodromic atrioventricular tachycardia. The third patient had dual atrioventricular nodal pathways and a right nodofascicular accessory pathway. The accessory pathway became manifest only when a critical atrioventricular delay was reached, indicating its association with the slow atrioventricular nodal pathway. Wide QRS tachycardia with left bundle branch block contour was documented, by means of the slow atrioventricular nodal pathway and nodofascicular fiber antegradely, and the proximal right bundle branch, the His bundle, and the fast atrioventricular nodal pathway retrogradely.     

快速心房起搏时SV间期与SS间期的比值在房室结折返性心动过速慢径消融中的应用

评价快速心房起搏时最快 1∶1房室传导的SV间期 (SV间期 )与 1∶1房室传导的最短S1S1间期 (SS间期 )的比值 (SV/SS)在房室结折返性心动过速 (AVNRT)慢径消融中的应用 ,将AVNRT分为房室结功能曲线连续组 (Ⅰ组 ,10例 )及房室结功能曲线不连续组 (Ⅱ组 ,17例 )测量心房分级递增刺激时的SS间期与SV间期及SV/SS ,并进行消融前、后和组间比较。结果显示 ,两组消融后SV间期较消融前明显缩短 (Ⅰ组 :2 2 1.0± 2 2 .3vs 35 7.0± 43.7ms;Ⅱ组 :2 0 2 .1± 30 .6vs 379.4± 44 .2ms,P均 <0 .0 5 ) ;消融前后SS间期无明显变化 (Ⅰ组 :310 .0± 40 .6vs 30 8.0± 36 .8ms;Ⅱ组 :332 .9± 48.1vs 336 .5± 6 2 .3ms) ;两组中所有患者消融前SV/SS比值均 >1,而消融后SV/SS比值均 <1。结论 :SV/SS可作为慢径消融成功终点的辅助观察指标之一 ,尤其对于房室结传导曲线呈连续性者 ,使用此方法可简便地观察消融终点 ,增加消融的目的性。     

Subthreshold stimulation in three types of reentrant supraventricular tachycardia: correlation with the results of catheter ablation.

The effects of subthreshold stimulation (STS) by direct current were investigated in 20 patients with atrioventricular nodal reentrant tachycardia (AVNRT), 27 with atrioventricular reentrant tachycardia (AVRT) and 3 with idiopathic atrial reentrant tachycardia (IART) STS was delivered to each eligible site for ablation prior to radiofrequency application. STS was defined as 'positive' if it could terminate the tachycardia or disrupt the conduction of accessory pathways without myocardial capture and defined as 'negative' if it could not. Radiofrequency ablation was performed irrespective of a positive or negative result from STS and was successful in all 50 patients. Among the 50 successful ablation sites, STS was positive at 26 sites (11 sites in AVNRT, 12 in AVRT and 3 in IART). STS was positive at 4 sites where ablation failed in 3 patients with AVRT and was negative at 8 sites where ablation was successful in 4 patients with AVNRT and 4 with AVRT. The positive and negative predictive value of STS for the detection of the optimal ablation site were, respectively, 100% and 74% in AVNRT, 73% and 72% in AVRT, and both 100% in IART STS-guided mapping is a specific method to predict the successful catheter ablation of reentrant supraventricular tachycardia.     

腺苷终止房室结和房室旁道折返性心动过速的心内电生理评价

探讨腺苷对阵发性室上性心动过速 (PSVT)的终止效果 ,观察PSVT终止后出现的心律失常。 2 5例患者 ,其中房室结折返性心动过速 (AVNRT) 11例、房室折返性心动过速 (AVRT) 14例 ,于心内电生理检查时 ,由前臂静脉注射(简称静注 )腺苷 6～ 12mg ,观察其终止心动过速的疗效和作用部位。结果 :11例AVNRT患者静注腺苷后 ,10例恢复窦性心律 ,其中 9例终止AVNRT于慢径前传 ,1例于快径逆传 ;14例AVRT患者静注腺苷后 ,14例均恢复窦性心律 ,终止AVRT 12例于房室结前传 ,2例于旁道逆传。心动过速终止后最常出现的心律失常是房性早搏和一过性Ⅰ和Ⅱ度房室阻滞 ;此外 ,室性早搏也很常见 ,部分患者可出现短阵室性心动过速 ,1例患者出现预激综合征伴心房颤动。结论 :腺苷终止PSVT有较高的成功率 ,但有潜在的促心律失常作用。     

希氏束旁起搏鉴别间隔部隐匿性AVRT与AVNRT的临床价值

目的：探讨希氏束旁起搏鉴别间隔部隐匿性房室旁道与慢一快型房室结折返性心动过速（AVNRT）的临床价值。方法：采用希氏束逆传不应期心室早搏刺激法将61例患者分别诊断为37例慢一快AVNRT和24例间隔部房室折返性心动过速（AVRT）；再对61例患者采用希氏束旁起搏方法进一步检测。结果：采用希氏束旁起搏法检测37例AVNRT患者中有6例未检测成功，其余31例均为逆传房室结图形；24例AVRT患者中4例未检测成功，15例呈逆传旁道／旁道图形，5例呈非逆传旁道／旁道图形。如以逆传旁道／旁道图形为标准，鉴别间隔快旁路引起的AVRT与慢一快型房室结折返性心动过速，敏感性75％，特异性可达1009／6。结论：希氏束旁刺激法对鉴别诊断AVRT与AVNRT有较高的特异性。     

心动过速RR间期交替的发生机制及导管射频消融治疗

目的　分析QRS心动过速伴RR间期长短交替的发生机制及导管射频消融情况。方法　对 6例心动过速伴RR间期长短交替患者 ,常规行动态心电图及食管电生理检查。心内电生理检查提示存在房室旁路或房性心动过速伴房室结双径路 ,先进行旁路或房性心动过速的消融 ,消融成功后再进行心内电生理检查 (包括应用异丙肾上腺素进行心动过速诱发 ) ,如不能诱发心动过速则终止手术。若提示存在房室结多径路 ,则进行慢路径改良术。结果　食管电生理检查提示 :4例患者存在房室旁路伴房室结双径路 ;2例患者存在房室结三径路。心内电生理检查及消融结果显示 :3例患者为房室旁路伴房室折返性心动过速 ,成功消融后不能诱发房室结折返性心动过速 ;1例患者同时存在房室及房室结折返性心动过速 ,成功消融房室旁路后再改良慢路径 ;2例患者为房室结三径路 ,经慢径路改良后房室结传导曲线连续 ,未诱发心动过速。 6例患者无并发症发生 ,随访期间无心动过速发作。结论　室上性心动过速伴RR间期交替发生率较低 ,且均与房室结传导不连续有关。心动过速伴RR间期交替发生机制较为复杂 ,除了与房室结纵向传导的不连续有关外 ,还与其不应期密切相关。食管电生理检查与心内电生理检查相比对揭示RR间期交替的发生机制具有较高的诊断价值。     

Detection of concealed left sided accessory atrioventricular pathway by P wave signal averaged electrocardiogram

Objectives. The purpose of this study was to examine whether P wave signal-averaged electrocardiogram (P-SAECG), which detects subtle changes in P wave, detects the concealed accessory atrioventricular pathway (AP).Background. It is difficult to differentiate atrioventricular reciprocating tachycardia (AVRT) due to the AP from atrioventricular nodal reentrant tachycardia (AVNRT) when the ventricular preexcitation is absent on 12-lead electrocardiograms. By electrophysiological studies, the anterograde conduction in the concealed AP is shown to be blocked near the AP-ventricular interface during sinus rhythm.Methods. P-SAECG during sinus rhythm was performed in 20 normal volunteers (control), 21 patients with AVRT due to the concealed AP, 19 with AVNRT, 22 with paroxysmal atrial fibrillation (PAF), and 7 with automatic atrial tachycardia (AT). The filtered P wave duration (FPD) and AR20 (power spectrum area ratio of 0–20 to 20–100 Hz) were measured and repeated in AVRT, AVNRT and AT groups at one week after catheter ablation.Results. The anterograde conduction in the concealed left-sided AP was confirmed in all cases by an electrophysiological study. The FPD in AVRT group was more prolonged than that in controls or AVNRT group. Although the FPD was similar between AVRT and PAF groups, AR20 differentiated between the two groups. Ablation of the concealed AP shortened FPD in AVRT group but that of the slow pathway or the atrial focus did not shorten in the AVNRT or AT groups, respectively. The changes in FPD after ablation were correlated with those in the duration of atrial activity by an electrophysiological study (r = 0.67).Conclusions. Our findings suggest that P-SAECG detects the concealed left-sided AP, providing a clinical tool in noninvasively assessing atrial activation patterns.