Radiofrequency Ablation of a Concealed Nodoventricular Mahaim Fiber Guided by a Discrete Potential

INTRODUCTION: We present the case of a 17-year-old woman who underwent an electrophysiological study and radiofrequency (RF) ablation of supraventricular tachycardia refractory to medical treatment. Two right-sided, concealed, nondecremental atrioventricular accessory pathways (AV-APs) involved in orthodromic circus movement tachycardias were identified. After RF ablation of both AV-APs, evidence of bidirectional dual AV nodal conduction was demonstrated and regular narrow complex tachycardia was induced. METHODS AND RESULTS: During the tachycardia, retrograde slow and fast AV nodal pathway conduction with second-degree ventriculoatrial (VA) block and VA dissociation were observed. During the tachycardia with second-degree VA block, ventricular extrastimuli elicited during His-bundle refractoriness advanced the next His potential or terminated the tachycardia. Mapping the right atrial mid-septal region, a distinct high-frequency activation P potential was recorded in a discrete area, two thirds of the way from the His bundle toward the os of the coronary sinus. Detailed electrophysiologic testing with the recordable P potential demonstrated that the tachycardia utilized a concealed nodoventricular AP arising from the proximal slow AV nodal pathway. CONCLUSION: The tachycardia with slow 1:1 VA conduction could be reset by ventricular extrastimuli elicited during His-bundle refractoriness advancing the subsequent activation P potential and atrial activation. RF ablation guided by recording of the activation P potential resulted in elimination of both the slow AV nodal pathway and the nodoventricular connection with preservation of the normal AV conduction system.     

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.     

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.     

Catheter ablation for cardiac arrhythmias

With the introduction of radiofrequency energy, catheter ablation has become an established technique for managing many cardiac rhythm disturbances. High efficacy and safety have been reported for accessory pathway ablation, selective fast and slow atrioventricular nodal pathway ablation to eliminate atrioventricular nodal reentrant tachycardia (while preserving atrioventricular conduction), atrioventricular junctional ablation to control the ventricular response to atrial tachyarrhythmias, ablation of the right bundle branch to eliminate bundle branch reentrant ventricular tachycardia, and ablation of the site of tachycardia origin in patients with ventricular tachycardia unassociated with structural heart disease. In addition, there has been active investigation into ablation techniques for more complex arrhythmias such as atrial tachycardia, atrial flutter, and ventricular tachycardia associated with structural heart disease.     

心室融合波伴心房激动提前对间隔旁路逆传的房室折返性心动过速的诊断作用

目的 观察心室融合波伴心房激动提前对间隔旁路逆传的顺向型房室折返性心动过速(OAVRT)的诊断作用。方法 按心内电生理检查标准和射频消融结果，将47例符合人选条件的患者分为两组：房室结折返性心动过速(AVNRT)组和间隔旁路逆传的0AVRT组，分别为24例和23例。心动过速时行心室期前程序刺激(RS2刺激)和心室快速刺激，测量体表心电图上心室融合波之后的心房激动时间是否提前。结果 RS2刺激和心室快速刺激均能形成多个心室融合波。AVNRT组无l例伴有心房激动提前(特异性100％)，而OAVRT组在心室刺激成分明显的心室融合波时，心房激动均被提前(敏感性100％)。两组间的差异十分显著(P＜0．001)。结论 心室融合波伴心房激动时间提前是诊断间隔旁路逆传OAVRT的可靠指标，具有敏感性和特异性高的特点，而且也可用于未能记录到希氏束电图的患者。     

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.     

Unusual induction of slow-fast atrioventricular nodal reentrant tachycardia. Report of two cases

INTRODUCTION: Generally, the induction of typical atrioventricular nodal reentrant tachycardia (AVNRT) occurs with a premature atrial stimulus that blocks in the fast pathway and proceeds down the slow pathway slowly enough to allow the refractory fast pathway time to recover. We describe two cases in which a typical AVNRT was induced in an unusual fashion. RESULTS: The first case is a 41-year-old man with paroxysmal supraventricular tachycardia. During the electrophysiology study, the atrial extrastimulus inducing the typical AVNRT was conducted simultaneously over the fast (AH) and the slow pathway (AH'). A successful ablation of the slow pathway was performed. During the follow-up no recurrence was noted. The second case is a 52-year-old woman with a Wolff-Parkinson-White syndrome due to a left posterior accessory pathway. After 5 minutes of atrioventricular reentrant tachycardia (AVRT) induced by a ventricular extrastimulus, a variability of the antegrade conduction was noted in presence of the same VA conduction. In fact, a short AH interval (fast pathway) alternated with a more prolonged AH intervals (slow pathway) that progressively lengthened until a typical AVNRT was induced. The ablation of the accessory pathway eliminated both tachycardias. DISCUSSION: A rare manifestation of dual atrioventricular nodal pathways is a double ventricular response to an atrial impulse that may cause a tachycardia with an atrioventricular conduction of 1:2. In our first case, an atrial extrastimulus was simultaneously conducted over the fast and the slow pathway inducing an AVNRT. This nodal reentry implies two different mechanisms: 1) a retrograde block on the slow pathway impeding the activation of the slow pathway from the impulse coming down the fast pathway, and 2) a critical slowing of conduction in the slow pathway to allow the recovery of excitability of the fast pathway. Interestingly, in the second case, during an AVRT the atrial impulse suddenly proceeded alternately over the fast and the slow pathway. The progressive slowing of conduction over the slow pathway until a certain point which allows the recovery of excitability of the fast pathway determines the AVNRT. This is a case of "tachycardia-induced tachycardia" as confirmed by the fact that the ablation of the accessory pathway eliminated both tachycardias.     

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。     

Paroxysmal supraventricular tachycardia initiated by a swallowing-induced premature atrial beat

We report a unique patient in whom electrophysiologic studies elucidated the mechanism of a rare form of swallowing-induced atrioventricular reentrant tachycardia, and for whom successful surgical ablation of an accessory pathway abolished intractable episodes of palpitation. A 64-year-old man was incapacitated by frequent attacks of palpitation following swallowing. Electrocardiograms documented paroxysmal supraventricular tachycardias initiated by a premature atrial beat or beats following swallowing. During electrophysiologic studies swallowing consistently induced premature atrial beats which in turn initiated a sustained atrioventricular reentrant tachycardia incorporating a retrogradely conducting left-sided concealed accessory pathway. The atrial activation sequence related to the premature atrial beats and the morphology of the premature P waves suggested that premature atrial beats originated in the right atrium. The mechanism of induction of premature atrial beats following swallowing remains obscure in our patient. Antiarrythmic drugs failed to prevent induction of sustained tachycardias during sequential electrophysiologic studies. The patient underwent successful surgical ablation of the accessory pathway and is free from palpitation 15 months after the surgery.     

Case Report: Clinical AV Nodal Reentrant Tachycardia in a Patient with Left Sided Accessory Pathway and Immediate Occurrence of Antidromic AV Reentrant Tachycardia after Slow Pathway Ablation

The only inducible arrhythmia in a patient with exclusive antegrade conducting left anterolateral accessory pathway, consists of slow/fast atrioventricular nodal reentrant tachycardia. After radiofrequency catheter ablation of the slow pathway, true antidromic AV reentrant tachycardia was easily induced by atrial pacing. Following ablation of the accessory pathway no arrhythmia could be induced.     

A technique for the rapid diagnosis of atrial tachycardia in the electrophysiology laboratory

OBJECTIVE: The purpose of this study was to determine if the atrial response upon cessation of ventricular pacing associated with 1:1 ventriculoatrial conduction during paroxysmal supraventricular tachycardia is a useful diagnostic maneuver in the electrophysiology laboratory. BACKGROUND: Despite various maneuvers, it can be difficult to differentiate atrial tachycardia from other forms of paroxysmal supraventricular tachycardia. METHODS: The response upon cessation of ventricular pacing associated with 1:1 ventriculoatrial conduction was studied during four types of tachycardia: 1) atrioventricular nodal reentry (n = 102), 2) orthodromic reciprocating tachycardia (n = 43), 3) atrial tachycardia (n = 19) and 4) atrial tachycardia simulated by demand atrial pacing in patients with inducible atrioventricular nodal reentry or orthodromic reciprocating tachycardia (n = 32). The electrogram sequence upon cessation of ventricular pacing was, categorized as "atrial-ventricular" (A-V) or "atrial-atrial-ventricular" (A-A-V). RESULTS: The A-V response was observed in all cases of atrioventricular nodal reentrant and orthodromic reciprocating tachycardia. In contrast, the A-A-V response was observed in all cases of atrial tachycardia and simulated atrial tachycardia, even in the presence of dual atrioventricular nodal pathways or a concealed accessory atrioventricular pathway. CONCLUSIONS: In conclusion, an A-A-V response upon cessation of ventricular pacing associated with 1:1 ventriculoatrial conduction is highly sensitive and specific for the identification of atrial tachycardia in the electrophysiology laboratory.     

Experience in 1,500 patients undergoing radiofrequency ablation in the treatment of tachycardias

Several reports have demonstrated that radiofrequency catheter ablation provides effective control of a variety of supraventricular and ventricular tachycardias. This report details the results of radiofrequency catheter ablation in 1500 consecutive patients with a wide variety of supraventricular and ventricular tachycardias treated in the Instituto Nacional de Cardiología "Ignacio Chavez", between April 22, 1992 until December of 1999. Tachycardias were associated with the presence of an accessory pathway in 987 patients (65.8%). Dual accessory pathways were present in 24 patients giving a total of 1,012 accessory pathways. The mechanism of the arrhythmia was atrioventricular nodal reentrant tachycardia in 321 patients (21.4%). Ablation of the reentrant circuit of atrial flutter within the right atrium was attempted in 109 (7.2%) patients and a primary atrial tachycardia in 13 patients (0.8%). Atrioventricular node ablation and permanent pacemaker implantation were performed in 26 patients (1.7%). Finally we performed radiofrequency catheter ablation in 37 (2.4%) patients with ventricular tachycardia. Radiofrequency catheter ablation was successful in 908 of 1012 (89.7%) patients with accessory pathways with a complication rate of 10 (0.98%) and a recurrence rate of 92 (9%). AV nodal reentry was successfully abolished in 319 of 321 patients by selective ablation of the slow pathway in 297/321 (92.5%) patients and the fast pathway in 22/24 (92%) patients. The complication rate of this group was 8/321 (2.4%) with a recurrence rate of 34 patients (10.5%). The reentrant circuit of atrial flutter was ablated successfully in 86 of 109 (76.8%) patients with a recurrence flutter in 14 (12.8%) patients. Five of 13 (38.4%) cases of primary atrial tachycardia were successfully ablated. Complete AV block was achieved in 26 of 26 (100%) patients with atrial fibrillation or flutter treated by AV nodal ablation. The procedure was successful in 28 of 37 (75.6%) patients with fascicular ventricular tachycardia. The results of this series of patients demonstrates the safety and efficacy of radiofrequency ablation for the treatment of a wide variety of taquicardias with high rate of success 1375 of 1500 patients (91.6%), with 142 recurrences (9.4%), 15 complications (1%), and no mortality.     

Concomitant reentrant tachycardias from concealed accessory atrioventricular bypass tract and atrioventricular nodal reentry in a patient with Williams syndrome.

Williams syndrome is characterized by a constellation of features including mental retardation and supravalvular aortic stenosis. Other cardiovascular abnormalities including arrhythmias contributing to sudden death have been described in these patients. In this report we describe a case of a 49-year-old female with Williams syndrome who presented with severe symptomatic supraventricular tachycardia. Cardiac electrophysiology study identified a left posteroseptal concealed accessory bypass tract responsible for atrioventricular reentrant tachycardia and a concomitant typical atrioventricular nodal tachycardia. Such unusual association of combination of two different types of supraventricular tachycardia and Williams syndrome has not been previously reported. Radiofrequency ablation was successfully performed to cure these arrhythmias.     

食管心房调搏对室上性心动过速诊断的准确性评价

评价食管电生理检查对室上性心动过速诊断的准确性。方法 比较102例室上性心动过速经心内和食管电生理检查的结果。结果 102例室上性心动过速101例分型诊断一致：房室折返性心运过速（AVRT）58例,房室结折返性心运过速（AVNRT）37例,房内折返性心动过速（IART）5例,窦房结折返性心动过速（SART）1例,房性自律性心动过速（AAT）1例。6例房性心动过速（IART5例,AAT1例）起源于右房还是左房和57例房室折返性心动过速的旁路位于右侧还是左侧,两种检查结果完全一致。结论 食管心房调搏对室上性心动过速的分型诊断和初步定位诊断具有很高的准确性,这对选择射频消融术病例和简化消融术程序具有重要意义。     

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。     

Typical atrioventricular nodal reentrant tachycardia in a patient with fasciculoventricular pathway

We report a 34-year-old female patient with preexcitation electrocardiogram and recurrent paroxysmal palpitations. Standard 12-lead electrocardiogram showed minimal preexcitation with normal PR interval and normal frontal QRS axis. The electrophysiologic study showed normal AH intervals, short HV intervals, and no change in the degree of preexcitation by rapid atrial pacing. These findings were compatible with the fasciculoventricular pathway. Typical atrioventricular nodal reentrant tachycardia with narrow QRS complex and normal HV interval was induced reproducibly by programmed electrical stimulation. Slow pathway was ablated successfully with radiofrequency catheter ablation, and then the patient remained asymptomatic during a follow-up of 12 months. Although the fasciculoventricular pathway is rare and supraventricular tachycardia in a patient with fasciculoventricular pathway may mimic Wolff-Parkinson-White syndrome, possibility of typical atrioventricular nodal reentrant tachycardia with fasciculoventricular pathway should be considered as a mechanism of supraventricular tachycardia in a patient showing preexcitation electrocardiogram.     

Atrioventricular nodal reentrant tachycardia treatment using novel potential

Radiofrequency ablation of atrioventricular nodal reentrant tachycardia is commonly guided by slow and sharp bipolar potentials of the atrioventricular slow nodal pathway. We optimized the morphology of the guiding potential by unipolar mapping of the slow nodal pathway. We identified a novel unipolar dual-component atrial electrogram at the anterior limb of the coronary sinus ostium. The first component was a positive delta-wave type that corresponded to the isoelectric phase on a bipolar electrogram. The second component had fast biphasic morphology and corresponded to the R wave on a bipolar atrial electrogram. Of 104 consecutive patients with typical atrioventricular nodal reentrant tachycardia, 51 were treated with ablation guided by the novel potential, and 53 underwent ablation using the conventional technique. There was no recurrence of tachycardia in any of these patients. In those treated by the novel potential, there was significantly less radiofrequency power applied and a shorter duration of application than in patients treated by the traditional approach. The novel approach to mapping and ablation of the slow nodal pathway in atrioventricular nodal reentrant tachycardia guided by unipolar recording was safe and effective, and comparable to the traditional technique.     

Two cases of polymorphic ventricular tachycardia induced by the administration of verapamil against paroxysmal supraventricular tachycardia

Verapamil is widely used for the termination of paroxysmal supraventricular tachycardia (PSVT) with little proarrhythmic effect. We describe two cases of PSVT that changed to non-sustained polymorphic ventricular tachycardia after administration of verapamil. Electrophysiological study revealed atrioventricular nodal reentrant tachycardia in the first case, and atrioventricular reentrant tachycardia due to a concealed left lateral accessory pathway in the second case. Catecholamine-induced automaticity was one of the possible mechanisms of VT in the first case, but the mechanism is unknown in the second case.     

射频导管消融360例儿童心律失常的疗效和安全性

目的 评价射频导管消融360例儿童心律失常的疗效和安全性。方法 回顾性分析2000年1月2013年12月360例因心律失常在我院接受射频导管消融的儿童患者360(男213例、女147)例,年龄15个月14(10±3)岁,平均体质量34 kg。结果 急性期消融成功率98.9%(356/360例),4例消融失败。360例患者中,阵发性室上性心动过速308例,占85.6%,307例(99.7%)患者消融成功,其中隐匿性房室旁路伴房室折返性心动过速121例、显性旁路(预激综合征)82例、房室结折返性心动过速105例;室性心律失常42例,其中室性早搏15例(均消融成功),27例室性心动过速(其中4例并发结构性心脏病,25例消融成功);房性心律失常10例(9例消融成功,其中典型心房扑动3例,不典型心房扑动1例,局灶性房性心动过速6例)。所有患儿围术期均未出现明重要并发症。术后随访至少12个月,随访期复发率为2.2%(8/356例),其中6例经再次消融成功。结论 射频导管消融术治疗有适应证的心律失常儿童安全有效。     

Unmasking of a concealed slow pathway by atrioventricular simultaneous basic pacing

A 71-year-old woman with narrow QRS tachycardia was referred for catheter ablation. The clinical tachycardia was diagnosed as slow/fast form of atrioventricular (AV) nodal reentrant tachycardia (AVNRT) with the upper common pathway. Although neither conventional nor double atrial programmed extrastimulation (APS) showed any evidence of a dual AV nodal pathway, AV simultaneous pacing during basic stimulation preceding APS (AVSP-APS) reproducibly revealed a dual AV nodal pathway as a double ventricular response. The AVSP-APS pacing method may be helpful to unmask a “concealed slow pathway” in patients with AVNRT.