Differentiating atrioventricular nodal reentrant tachycardia from tachycardia via concealed accessory pathway

Studies analyzing the diagnostic value of 12-lead electrocardiographic criteria differentiating slow-fast atrioventricular nodal reentrant tachycardia (AVNRT) from atrioventricular reentrant tachycardia (AVRT) due to concealed accessory pathway have shown inconsistent results. In 97 patients (50 with AVNRT, 47 with AVRT) 12-lead electrocardiograms (ECGs) were recorded during sinus rhythm and tachycardia (QRS <120 ms). The ECGs were blinded for diagnosis and patient and analyzed independently by 2 electrophysiologists. The studied criteria differentiating AVNRT from AVRT included pseudo-r'/S, the presence of a retrograde P wave, RP interval, ST-segment depression >/=2 mm with the number and location of the affected leads, QRS amplitude, and cycle length alternans.     

Para-Hisian entrainment: a novel pacing maneuver to differentiate orthodromic atrioventricular reentrant tachycardia from atrioventricular nodal reentrant tachycardia

INTRODUCTION: Para-Hisian pacing during sinus rhythm can help to identify the presence of an accessory pathway (AP). In this maneuver, the retrograde activation time and pattern are compared during capture and loss-of-capture of the His bundle while pacing from a para-Hisian position. However, identification of a retrograde AP does not necessitate that it is operative during the tachycardia of interest; conversely, slowly conducting or "distant" bypass tracts may not be identified. We evaluated the utility of entrainment or resetting of tachycardias from the para-Hisian position to help distinguish atrioventricular nodal reentrant tachycardia (AVNRT) from orthodromic atrioventricular tachycardia (AVRT). METHODS AND RESULTS: Para-Hisian entrainment/resetting was evaluated in 50 patients: 33 with AVNRT and 17 with AVRT. The maneuvers were performed using a standard quadripolar catheter placed at the His position: low output for right ventricular (RV) capture and high output for both RV and His capture. The retrograde atrial activation sequence, SA interval (interval from stimulus to earliest retrograde atrial activation), and "local" VA interval (interval between the ventricular and atrial electrograms at the site of earliest retrograde atrial activation) were compared between His and His/RV capture. The DeltaSA was > 40 ms in patients with AVNRT and was < 40 ms in all but one patient with AVRT. In concert with the DeltaSA interval, the DeltaVA interval was able to fully define the mechanism of the tachycardia in all patients studied. CONCLUSION: Para-Hisian entrainment/resetting can determine the course of retrograde conduction operative during narrow complex tachycardias. It is a useful diagnostic maneuver in differentiating AVNRT and orthodromic AVRT.     

Differentiating atrioventricular nodal reentrant tachycardia from junctional tachycardia: novel application of the delta H-A interval

Introduction: Junctional tachycardia (JT) and atrioventricular nodal reentrant tachycardia (AVNRT) can be difficult to differentiate. Yet, the two arrhythmias require distinct diagnostic and therapeutic approaches. We explored the utility of the delta H-A interval as a novel technique to differentiate these two tachycardias.
Methods: We included 35 patients undergoing electrophysiology study who had typical AVNRT, 31 of whom also had JT during slow pathway ablation, and four of whom had spontaneous JT during isoproterenol administration. We measured the H-A interval during tachycardia (H-A_T) and during ventricular pacing (H-A_P) from the basal right ventricle. Interobserver and intraobserver reliability of measurements was assessed. Ventricular pacing was performed at approximately the same rate as tachycardia. The delta H-A interval was calculated as the H-A_P minus the H-A_T.
Results: There was excellent interobserver and intraobserver agreement for measurement of the H-A interval. The average delta H-A interval was −10 ms during AVNRT and 9 ms during JT (P < 0.00001). For the diagnosis of JT, a delta H-A interval ≥ 0 ms had the sensitivity of 89%, specificity of 83%, positive predictive value of 84%, and negative predictive value of 88%. The delta H-A interval was longer in men than in women with JT, but no gender-based differences were seen with AVNRT. There was no difference in the H-A interval based on age ≤ 60 years.
Conclusion: The delta H-A interval is a novel and reproducibly measurable interval that aids the differentiation of JT and AVNRT during electrophysiology studies.     

Development of multiform ventricular tachycardia during atrioventricular nodal reentrant tachycardia

A woman of 18 presented with a supraventricular tachycardia, subsequently shown to be caused by atrioventricular nodal reentry, which abruptly deteriorated to a multiform ventricular tachycardia. She had not received any antiarrhythmic drugs nor did she have any of the disorders that are usually associated with this atypical ventricular tachycardia.     

房室折返和房室结折返性心动过速患者的个性分析

目的探讨房室折返性心动过速(AVRT)和房室结折返性心动过速(AVNRT)患者的个性特征。方法采用龚耀先修订的艾森克个性问卷量表,对83例AVRT、105例AVNRT患者射频消融前后和50例对照组正常人的精神质(P)、内外向(E)、情绪稳定性(N)和掩饰倾向(L)值进行测量。结果射频消融前后,各组之间的P、E、N和L值相比较差异无显著性(P>0.05);射频消融前后AVNRT组内女性患者的N分值较男性高(分别为12.93±2.83vs9.88±2.61;12.84±2.87vs9.87±2.64;P均<0.05)。结论AVNRT女性患者具有神经质倾向,这可能是在AVNRT中女性占多数的原因之一。     

Development of multiform ventricular tachycardia during atrioventricular nodal reentrant tachycardia.

A woman of 18 presented with a supraventricular tachycardia, subsequently shown to be caused by atrioventricular nodal reentry, which abruptly deteriorated to a multiform ventricular tachycardia. She had not received any antiarrhythmic drugs nor did she have any of the disorders that are usually associated with this atypical ventricular tachycardia.     

界嵴心动过速与房室结折返性心动过速并存时心房激动的竞争夺获现象

目的　阐明右心房内界嵴心动过速 (CT AT)与房室结折返性心动过速 (AVNRT)并存时心房激动的竞争夺获现象 ,分析其可能的电生理机制及导管消融策略。方法　 3例患者中 ,女性 2例 ,男性 1例 ,年龄 4 9～ 5 7岁 ,心动过速病史 10～ 2 0年。 3例患者均无器质性心脏病。经左股静脉置入 9F球囊电极至右心房中部并展开 ,球囊中心位于希氏束水平。构建右心房构型后 ,经高位右心房程序刺激诱发心动过速 ,建立心动过速的心内膜等电势图 ,然后分析心动过速的起源、传导方向 ,由此确定消融的部位和方法。经导航系统引导消融导管至拟订靶点处 ,每点予以 6 0W、6 0s、6 0℃温控消融 ,直至心动过速不能诱发。结果　 3例患者均可诱发出CT AT和AVNRT。例 1CT AT和AVNRT同时被诱发 ,两种心动周期比较接近 ,分别为 2 83ms和 2 6 2ms ;心内膜电生理提示心动过速由CT AT逐渐移行成AVNRT。例 2首先诱发出CT AT ,随之又诱发出AVNRT ,且两者并存 ,两种心动周期基本相同 ,分别为 35 0ms和 35 9ms;心内膜电生理示右心房上部随CT激动 ,下部及间隔部随AVNRT激动。例 3AVNRT比CT更易诱发 ,两者不在同一时间段出现 ,前者心动过速周期为 2 73ms ,后者为 36 5ms。3例患者均先行常规方法消融慢径 ,使AVNRT不再诱发。CT AT经非接触球囊导管     

Retrograde block during dual pathway atrioventricular nodal reentrant paroxysmal tachycardia

There are limited reported data regarding the occurrence of retrograde block during dual pathway atrioventricular (A-V) nodal reentrant paroxysmal tachycardia. This study describes two patients with this phenomenon. The first patient had 2:1 and type 1 retrograde ventriculoatrial block during the common variety of A-V nodal reentrance (slow pathway for anterograde and fast pathway for retrograde conduction). Fractionated atrial electrograms suggested that the site of block was within the atria. The second patient had type 1 retrograde block (between the A-V node and the low septal right atrium) during the unusual variety of A-V nodal reentrance (stow pathway for retrograde and fast pathway for anterograde conduction). The abolition of retrograde block by atropine suggested that the site of block was within A-V nodal tissue. Both cases demonstrate that intact retrograde conduction is not necessary for the continuation of A-V nodal reentrant paroxysymal tachycardia. Case 2 supports the hypothesis that the atria are not a requisite part of the A-V nodal reentrant pathway.     

Double ventricular responses during extrastimulation of atrioventricular nodal reentrant tachycardia

In patients with dual atrioventricular (AV) nodal pathways,double ventricular responses to a single atrial depolarizationhave been shown to occur, but virtually only during a trialpacing in sinus rhythm. We report on a patient with a slow-fastform of AV nodal reentrant tachycardia who exhibited doubleventricular responses following extrastimulation during AV nodalreentrant tachycardia. The phenomenon of double ventricularresponses during the tachycardia was demonstrated by ex trastimulationfrom the proximal coronary sinus. Retrograde unidirectionalblock in the slow pathway, and an anterograde effective refractoryperiod that was shorter in the fast pathway than that in theslow pathway, are suggested.     

Significance of bundle branch block during atrioventricular nodal reentrant tachycardia

There are very limited data on the effects of bundle branch block (BBB) in patients with atrioventricular nodal reentrant tachycardia (AVNRT). Studies in a total of 155 patients with 162 episodes of AVNRT were retrospectively analyzed. A total of 38 patients (25%) developed spontaneous right BBB, whereas 5 (3%) developed left BBB during tachycardia. Five of the 38 (13%) with right BBB showed near identical prolongation of both the ventriculoatrial (VA) (15 +/- 5 ms; 10 to 23) and His to atrial intervals (HA) (14 +/- 4 ms; 10 to 20) with an identical atrial activation sequence for both right BBB or normal QRS tachycardia complexes. In contrast, all 5 patients with left BBB showed a decrease in the VA (-18 +/- 11 ms; 10 to 36) with unchanged HA comparing left BBB to normal QRS patterns during AVNRT. The magnitude of prolongation of the His to ventricular interval (HV) during left BBB (19 +/- 12 ms; 10 to 40) was nearly identical to the decrease in the VA. In conclusion, prolongation of VA and HA with unchanged HV in patients with AVNRT and right BBB suggests that right BBB is due to a block in the fibers in close proximity to the His recording site. The data suggest that fibers in the His bundle are predestined to activate the right bundle branch, and in AVNRT the lower turnaround point may be within the His bundle.     

Double loop reentrant atrial tachycardia following ablation for atrioventricular nodal reentrant tachycardia

We report a patient with a history of multiple ablations for recurrent atrioventricular nodal reentrant tachycardia who developed an atrial tachycardia four years after his last procedure. Subsequent electroanatomical mapping demonstrated double loop macro-reentrant atrial tachycardia consistent with a roof dependent flutter and a perimitral flutter. We successfully terminated the tachycardia by targeting isthmuses at sites of prior ablation.     

Mechanisms underlying atrioventricular nodal conduction and the reentrant circuit of atrioventricular nodal reentrant tachycardia using optical mapping

The findings of multiple nondiscrete AV nodal pathways and asymmetric transitional zone provide a biophysical basis for understanding normal and abnormal AV node electrophysiology. Unidirectional block occurring at the transitional zone transforms the nondiscrete pathways model into a classic dual pathways physiology for AVNRT.     

Implications of 2:1 atrioventricular block during typical atrioventricular nodal reentrant tachycardia

Objective The effects of 2:1 AV block (AVB) on AV nodal reentrant tachycardia (AVNRT) remain to be elucidated. This study was performed to localize the site of 2:1 AVB and elucidate the effects of 2:1 AVB on typical AVNRT. Methods The His bundle (HB) electrograms during typical AVNRT with 2:1 AV block were reviewed in 24 patients. It was hypothesized that if 2:1 AVB at the HB or below changed tachycardia cycle length (TCL), the lower turnaround point of the reentrant circuit (RC) might be located within the HB and parts of the HB might be involved in the RC. Results A HB potential was absent in blocked beats during 2:1 AVB in four patients (supra-Hisian block), and the maximal amplitude of the HB potential in blocked beats was the same as that in conducted beats in four patients (infra-Hisian block), and was significantly smaller than that in conducted beats (0.1 ± 0.1 versus 0.5 ± 0.2 mV, P < 0.05) in 16 patients (intra-Hisian block). Eight patients (33%) with intra-Hisian block had a nearly identical prolongation of the H–A and A–A intervals in blocked beats (12 ± 3 and 13 ± 2 ms, respectively) with unchanged A–H intervals, while the remaining 16 patients (67%) exhibited invariable A–A and/or H–A intervals. Conclusion The site of 2:1 AVB during typical AVNRT was estimated to be at the HB or below in 83% of the cases. Two-to-one intra-Hisian block transiently prolonged TCL, possibly indicating involvement of the proximal HB in the RC in one-third of typical the AVNRT cases with 2:1 AVB.     

Unusual variant of atrioventricular nodal reentrant tachycardia.

Electrophysiologic study in a patient with supraventricular tachycardia revealed an unusual activation pattern in the coronary sinus (CS) electrodes. Pacing maneuvers confirmed the tachycardia was a slow-slow AV nodal reentrant tachycardia with double potentials in the distal CS electrodes due to an earlier left atrial signal (50 ms) and later CS musculature activation. The left-sided AV nodal inputs were successfully ablated from within the CS.     

快慢型房室结折返性心动过速的电生理特点

目的分析快慢型房室结折返性心动过速（AVNRT）患者的临床特征、心电网和电生理检查特点、射频消融治疗特点,旨在为临床长RP。心动过速鉴别提供帮助。方法11例经心内电生理检查证实为慢快型房室结折返性心动过速的患者,回顾性分析其临床特征、心电图特点及电生理检查特点及射频消融治疗。结果心动过速表现为窄QRs波心动过速,RP’〉P’R,P。在Ⅱ、Ⅲ、aVF导联倒置,RP’间期为350±25ms,心率为1664-30bpm。11例患者中有3例出现室房逆传跳跃现象。心房程序刺激无明显跳跃现象,11例均可由心房StS：刺激诱发心动过速发作,且容易诱发,容易终止。心动过速发作时,5例CS9．10A波最早,6例HiS的A波最早,其中1例静推ATP心动过速终止。11例患者中9例经房室结改良消融传统慢径获得成功,2例在冠状静脉窦内消融成功,术后随访3个月以上均未再发作心动过速。结论长RP’心动过速的诊断和鉴别诊断有一定困难,如能排除慢旁道和房速,应考虑快慢型房室结折返性心动过速。     

Coincident atrioventricular nodal reentrant and idiopathic ventricular tachycardia

Double tachycardia appears to be relatively rare. Our single-center experience of coincident typical atrioventricular nodal reentrant and idiopathic ventricular tachycardia was reviewed. Between September 2003 and February 2005, 40 patients with idiopathic ventricular tachycardia underwent catheter ablation for right ventricular outflow tract tachycardia in 20, left ventricular outflow tract tachycardia in 2, and left ventricular septal tachycardia in 18. In 5 patients (2 men and 3 women, aged 27-49 years) there was a combination of typical atrioventricular nodal reentrant tachycardia and idiopathic ventricular tachycardia. They had no structural heart disease. The presenting arrhythmia was supraventricular in one and ventricular in 4. There was no case of inducibility of one arrhythmia by the other (tachycardia-induced tachycardia), but an interaction was observed in one tachycardia in which inducibility was seen only after ablation of the other arrhythmia. Radiofrequency ablation of either arrhythmia did not prevent induction of the other.