Pacing Maneuver in the Diagnosis of the Mechanism of Supraventricular Tachycardia

Pacing and entrainment maneuvers are essential for establishing the mechanism of supraventricular tachycardia (SVT), but may fail to do so if the SVT terminates or if pacing results in atrioventricular (AV) dissociation as opposed to entrainment of the arrhythmia. We present an unusual case of typical AV nodal reentrant tachycardia (AVNRT) with high degree AV block in which the diagnosis was confirmed using a novel maneuver consisting of simultaneous atrial and ventricular (A + V) pacing. The reproducible response to A + V pacing at varying cycle lengths established the diagnosis of AVNRT in this case. (PACE 2011; 34:e90–e93)     

Fast pathway ablation in a patient with PR prolongation

The classical form of typical atrioventricular node reentrant tachycardia (AVNRT) is a “slow-fast” pathways tachycardia, and the usual therapy is an ablation of the slow pathway since it carries a low risk of atrioventricular (AV) block. In patients with long PR interval and/or living on the anterograde slow pathway, an alternative technique is required. We report a case of a 42-year-old lady with idiopathic restrictive cardiomyopathy, persistent atrial fibrillation status post pulmonary vein isolation, and premature ventricular complex ablation with a systolic dysfunction, who presented with incessant slow narrow complex tachycardia of 110 bpm that appeared to be an AVNRT. Her baseline EKG revealed a first-degree AV block with a PR of 320 ms. EP study showed no evidence of anterograde fast pathway conduction. Given this fact, the decision was to attempt an ablation of the retrograde fast pathway. The fast pathway was mapped during tachycardia to its usual location into the anteroseptal region, then radiofrequency ablation in this location terminated tachycardia. After ablation, she continued to have her usual anterograde conduction through slow pathway and the tachycardia became uninducible. In special populations with prolonged PR interval or poor anterograde fast pathway conduction, fast pathway ablation is the required ablation for typical AVNRT.     

The Control of Atrial Contraction by Ventriculo-Atrial Pacing in the Dog With AV Block

Atrial contraction in dogs with atrioventricular (AV) block was controlled by multiple atrial stimuli delivered during ventricular diastole. Acute hemodynamic changes were assessed. At a ventricular rate of 60 bpm, the spontaneous atrial rate averaged 83, and atrial cannon waves were frequent. When the atria were given two stimuli at an interval of 500 ms during ventricular diastole, the cannon waves were eliminated completely, and a fall in mean central venous pressure and a rise in systemic blood pressure were found. At a pacing rate of 90 bpm, similar changes in the cannon waves, mean central venous pressure, and systemic blood pressure were found when two atrial stimuli followed ventricular stimulation. Ventriculo-atrial multiple pacing may be useful in both clinical and experimental AV block.     

Double Ventricular Responses to a Single Atrial Depolarization in a Patient with Dual AV Nodal Pathways

Electrophysiological study was performed in a patient with atrioventricular nodal reentrant tachycardia (AVNRT). Double ventricular responses through dual AV nodal pathways were observed by atrial extrastimulus technique followed by initiation of AVNRT. The difference in conduction time between the slow and fast AV nodal pathways was longer than 320 msec. A ventricular extrastimulus delivered during sinus rhythm, which was not followed by ventriculoatrial conduction, also induced AVNRT. These findings indicated the presence of an antegrade critical delay and retrograde block in the slow AV nodal pathway, criteria necessary for the occurrence of a double ventricular response.     

"V-H-A Pattern" as a criterion for the differential diagnosis of atypical AV nodal reentrant tachycardia from AV reciprocating tachycardia

BACKGROUND: During ventricular extrastimulation, His bundle potential (H) following ventricular (V) and followed by atrial potentials (A), i.e., V-H-A, is observed in the His bundle electrogram when ventriculo-atrial (VA) conduction occurs via the normal conduction system. We examined the diagnostic value of V-H-A for atypical form of atrioventricular nodal reentrant tachycardia (AVNRT), which showed the earliest atrial activation site at the posterior paraseptal region during the tachycardia. METHODS: We prospectively examined the response of VA conduction to ventricular extrastimulation during basic drive pacing performed during sinus rhythm in 16 patients with atypical AVNRT masquerading atrioventricular reciprocating tachycardia (AVRT) utilizing a posterior paraseptal accessory pathway and 21 with AVRT utilizing a posterior paraseptal accessory pathway. Long RP' tachycardia with RP'/RR > 0.5 was excluded. The incidences of V-H-A and dual AV nodal physiology (DP) were compared between atypical AVNRT and AVRT. RESULTS: V-H-A was demonstrated in all the 16 patients (100%) in atypical AVNRT and in only 1 of the 21 (5%) in AVRT (P < 0.001). DP was demonstrated in 10 patients (63%) in atypical AVNRT and in 4 (19%) in AVRT (P < 0.05). The sensitivity of V-H-A for atypical AVNRT was higher than that of DP (P < 0.05). Positive and negative predictive values were 94% and 100%, respectively, for V-H-A and 71% and 74%, respectively, for DP. CONCLUSIONS: The appearance of V-H-A during ventricular extrastimulation is a simple criterion for differentiating atypical AVNRT masquerading AVRT from AVRT utilizing a posterior paraseptal accessory pathway.     

Use of Double Ventricular Extrastimulation to Determine the Preexcitation Index in Atrioventricular Nodal Reentrant Tachycardia

The ability of single paced ventricular beats during tachycardia to penetrate the tachycardia circuit and reset the subsequent atrial depolarization (atrial preexcitation), enabling calculation of the "preexcitation index," can be helpful in analyzing supraventricular tachycardias, However, the ventricular refractory period often prevents ventricular capture of beats with the necessary prematurity to demonstrate atrial preexcitation, particularly in atrioventricular nodal reentrant tachycardia (AVNRT). We hypothesized that the use of double premature stimuli could overcome this limitation. In 25 consecutive patients with either AVNRT or atrioventricular reciprocating tachycardia (AVRT) we attempted to demonstrate atrial preexcitation with single and double ventricular extrastimuli. Whereas atrial preexcitation with a single extrastimulus could only be achieved in 3 of 11 patients with AVNRT, all but 1 patient demonstrated atrial preexcitation with the use of double ventricular extrastimuli. On the other hand, in all but 1 patient with AVRT, atrial preexcitation could be achieved with single and double extrastimuli. A formula was derived for obtaining a preexcitation index with double extrastimuli and shown to correspond closely with the preexcitation index obtained with a single extrastimulus in the 16 patients in whom atrial preexcitation could be achieved with single and double extrastimuli. Thus, this technique significantly enhances the ability to achieve atrial preexcitation and to calculate the preexcitation index in patients with AVNRT, and thus may be useful in deciphering tachycardia mechanism in some patients, as well as being a useful technique in studying the electrophysiological properties of the antegrade and retrograde limbs of AVNRT.     

“Pseudo PJRT”—Fast‐Slow AV Nodal Reentrant Tachycardia Presenting with Tachycardia‐Induced Cardiomyopathy

A 52‐year‐old woman presented with left ventricular (LV) dysfunction and incessant narrow complex tachycardia. Electrocardiogram and clinical picture were suggestive of a permanent form of junctional reciprocating tachycardia, but electrophysiology study showed the tachycardia to be a fast‐slow form of atrioventricular nodal reentrant tachycardia (AVNRT). Slow pathway ablation terminated the tachycardia and the LV dysfunction resolved completely at follow‐up. Fast‐slow AVNRT has not been reported to present in incessant form, and the mechanism in this patient was absent retrograde fast pathway conduction resulting in easy initiation and maintenance of tachycardia. (PACE 2013; 36:e4–e6)     

Inducible atrioventricular nodal reentrant echo behind organic 2:1 infra-hisian block during sinus rhythm

A 77-year-old male patient with an intermittent 2:1 infra-Hisian block during sinus rhythm was presented with dizziness and near-syncope. During electrophysiological (EP) study, dual atrioventricular (AV) nodal pathways and retrograde fast pathway were easily induced by atrial and ventricular programmed stimulation, respectively. A typical slow-fast AV nodal reentrant echo beat also could be demonstrated by single atrial extrastimulation. Atrioventricular nodal reentrant tachycardia (AVNRT) can occasionally exhibit 2:1 AV block. Conversely, AV nodal reentry property had been rarely reported behind 2:1 infra-Hisian block. The EP presentation from this case may support the notion that tissues below the His are not part of the reentrant circuit of AVNRT.     

Diagnostic Value of Comparison of Ventriculoatrial Interval During Junctional Tachycardia and Right Ventricular Apical Pacing

We postulated that comparison of ventriculoatrial intervals during junctional tachycardia and during right ventricular apical pacing may provide similar diagnostic information to that obtained from the insertion of ventricular extrasystoles during tachycardia. We studied 39 patients with either atrioventricular reentrant tachycardia (AVRT) (23 patients) using a single atrioventricular accessory pathway or atrioventricular nodal reentrant tachycardia (AVNRT) (16 patients). Ventriculoatrial [VA] intervals were measured during tachycardia, during right ventricular apical pacing at the same rate as that of the tachycardia and following a ventricular extrasystole delivered at the minimum reset interval (minimum prematurity of a ventricular extrasystole required to advance the subsequent atrial complex by more than 10 msec). The difference between the minimum VA interval during tachycardia and during ventricular pacing was closely related to both the minimum reset interval (r = 0.92, P less than 0.001) and the difference between the minimum VA interval during tachycardia and following a ventricular extrasystole delivered at the minimum reset interval (r = 0.97, P less than 0.001) in the 23 patients in whom the minimum reset interval could be determined. The ratio between the minimum ventriculoatrial interval during tachycardia and ventricular pacing could be determined in all cases and was between 1.53 and 1.68 in AVRT with right free wall (two patients), 0.94 and 1.29 with anteroseptal (three patients), 0.91 and 1.08 with posteroseptal (five patients) and 0.48 and 0.71 with left free wall (13 patients) pathways, while it was between 0.32 and 0.27 in AVNRT (16 patients). The ratio was more discriminative when corrected for ventricular latency and was also useful when calculated from the high right atrial electrogram. We concluded that comparison of ventriculoatrial intervals during junctional tachycardia and during right ventricular apical pacing can discriminate between the mechanisms of tachycardia and the site of pathway. It provides similar information to that obtained from ventricular extrasystoles during tachycardia with the advantage that it can be determined in all cases.(ABSTRACT TRUNCATED AT 400 WORDS)     

Upper and Lower Common Pathways in Atrioventricular Nodal Reentrant Tachycardia:

The concepts of upper and lower common pathways represent long-standing controversies of atrioventricular nodal reentrant tachycardia (AVNRT). Over the last years there has been considerable evidence against the presence of a lower and, especially, an upper common pathway as distinct entities that can be identified in most patients with atrioventricular reentrant tachycardia. The mechanism and relevance of these concepts remain speculative.     

Pseudotermination of atrioventricular nodal reentrant tachycardia related to isorhythmic atrioventricular dissociation

Unusual manifestations of the mode of termination were observed in a patient with atrioventricular nodal reentrant tachycardia (AVNRT). After administration of verapamil during AVNRT, isorhythmic atrioventricular dissociation occurred without termination of the tachycardia. The sinus rate was slightly faster than that of the AVNRT, leading to the P wave preceding the QRS complex with a normal PR interval (e.g., pseudotermination). This phenomenon emphasizes the importance of continuous monitoring during an attempt to terminate AVNRT.     

aVR导联在阵发性室上性心动过速中的鉴别诊断价值

目的分析心电图aVR导联形态在阵发性室上性心动过速中的鉴别诊断价值。方法选取泰达国际心血管病医院行射频消融的室上性心动过速患者157例,男69例,女88例,年龄13~74岁,平均（41.9±19.2）岁,以心内电生理检查结果为金标准,分为慢快型房室结折返性心动过速组（SF-AVNRT组,n=89）和左侧房室旁路参与的房室折返性心动过速组（AVRT组,n=68）,入选者在窦性心律和室上性心动过速时无束支传导阻滞。结果与窦性心律时相比,SF-AVNRT组aVR导联QRS波终末部形态改变（假性r波或粗顿）的发生率73.0%,AVRT组aVR导联QRS波终末部形态改变（假性r波或粗顿）的发生率为1.5%,差异有统计学意义（P〈0.01）;与窦性心律时相比,SF-AVNRT组aVR导联ST段抬高、水平型移行或T波降支切迹的发生率为2.2%,AVRT组aVR导联ST段抬高、水平型移行或T波降支切迹的发生率为89.7%,差异有统计学意义（P〈0.05）。结论与窦性心律时相比,SF-AVNRT和AVRT在aVR导联具有不同的心电图特点,aVR导联QRS波终末部形态和ST段形态对判断室上性心动过速的类型具有重要意义,需高度重视aVR导联在室上性心动过速中的鉴别诊断价值。     

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。     

体表心电图V1和aVL/aVR导联对房室结折返性心动过速的诊断价值

目的探讨体表心电图V1联合aVL或aVR导联对房室结折返性心动过速(AVNRT)的诊断价值。方法143例窄QRS心动过速患者的体表心电图,含窦性心律和心动过速心电图。由两位未知心动过速类型的心电生理医师进行诊断,记录包括V1导联假r′波、aVL导联末端切迹、心动过速RP′间期≥100 ms等指标,心动过速类型由心内电生理检查确定。结果AVNRT患者年龄较大(P<0.01),女性较多(72.4% vs 50.0%,P<0.01)。aVL导联末端切迹对于诊断AVNRT具有较高敏感度（60.9%）和特异度（89.3%）,高于传统V1导联假r′和下壁导联假s波（P均小于0.05）;联合V1导联假r′和aVL导联末端切迹或aVR导联假r′波明显提高AVNRT诊断敏感度至78.2%和74.7%,而阳性预测值无明显降低。RP′间期≥100 ms诊断顺向型房室折返性心动过速(AVRT)具有较高敏感度和特异度(敏感度69.6%, 特异度87.4%),联合aVR导联ST段J点后80 ms下斜型抬高超过1.5 mV指标,明显提高AVRT诊断敏感度（89.2%）。结论体表心电图V1和aVL或aVR导联可提高AVNRT诊断价值。     

Uncommon etiology of syncope in a patient with isolated ventricular noncompaction

Isolated noncompaction of left ventricular myocardium (IVNC) is categorized as an unclassified cardiomyopathy by the World Health Organization.We describe the case of a 29-year-old woman who was diagnosed with IVNC after suffering two syncopes caused by an atrioventricular nodal reentrant tachycardia (AVNRT) that was successfully ablated. We report successful radiofrequency ablation in an adult with this cardiomyopathy. Although the presence of syncope in these patients obliged us to rule out a ventricular tachycardia as the most probable etiology, our case shows how an exhaustive study is needed to look for other possible and curable causes.     

射频消融治疗快速心律失常200例回顾分析

目的：本文报告我院自１９９３年４月～１９９７年１２月用射频消融方法治疗快速心律失常２００例。方法：快速心律失常类别包括：房室结折返性心动过速,房室折返性心动过速,特发性室性心动过速,阵发性心房扑动。结果：本组第一次消融总成功率为９３．５％,第二次消融总成功率为９８．５％;总复发率为２．５％;并发症发生率为２％。与国内射频消融治疗快速心律失常注册登记结果类似。结论：射频消融已成为治疗快速心律失常简捷而有效的方法。但作为术者,应努力提高电生理知识水平,熟悉心脏Ｘ线影像学,提高射频消融的成功率,减少并发症。     

Coincident Idiopathic Left Ventricular Tachycardia and Atrioventricular Nodal Reentrant Tachycardia: Control by Radiofrequency Catheter Ablation of the Slow Atrioventricular Nodal Pathway

A healthy 37-year-old male presented with a history of frequent palpitations and sustained wide QRS complex tachycardia with a right bundle branch block and left axis morphology. Serial electrophysiological studies revealed two inducible tachycardias, which were shown to represent atrioventricular nodal reentrant tachycardia and idiopathic left ventricular tachycardia. Transformation from one tachycardia to the other occurred spontaneously as well as following atrial or ventricular pacing. Radiofrequency catheter ablation of the slow atrioventricular nodal pathway resulted in cure of atrioventricular nodal reentrant tachycardia and the prevention of spontaneous recurrence of ventricular tachycardia, suggesting a role of atrioventricular nodal reentrant tachycardia in triggering the clinical episodes of ventricular tachycardia. The patient has remained asymptomatic without antiarrhythmic therapy for 8 months.     

宽QRS波心动过速患者食管电生理检查误漏诊分析

目的 分析宽QRS波心动过速患者食管电生理检查误漏诊的原因.方法 回顾性分析宽QRS波心动过速食管电生理误漏诊2例的临床资料.结果 本文2例均以心悸就诊,行食管调搏检查,例1诊断为隐匿性房室旁道并房室折返性心动过速伴室内差异性传导,例2诊断为左室阵发性室上性心动过速合并左侧隐匿旁管并房室折返性心动过速.后经心内电生理检查,例1确诊为右侧马海姆（Mahaim）纤维参与的逆向性房室折返性心动过速;例2漏诊室性心动过速.均经射频消融术治疗痊愈.结论 食管电生理是临床诊断快速心律失常的常用方法,对复杂少见的宽QRS波心动过速应尽量将食管心房调搏资料收集齐全,使心动过速的机制明朗化,避免临床误漏诊的发生.     

Acute effects of simvastatin to terminate fast reentrant tachycardia through increasing wavelength of atrioventricular nodal reentrant tachycardia circuit

Simvastatin (SV) leads to reduction of ventricular rhythm during atrial fibrillation on rabbit atrioventricular (AV) nodes. The aim of our study was (i) to determine the frequency‐dependent effects of SV in a functional model, and (ii) to assess the effects of SV to suppress experimental AV nodal reentrant tachycardia (AVNRT). Selective stimulation protocols were used with two different pacing protocols, His to atrial, and atrial to atrial (AA). An experimental AVNRT model with various cycle lengths was created in three groups of perfused rabbit AV nodal preparations (n = 24) including: SV 3 μm , SV 7 μm , and verapamil 0.1 μm . SV increased nodal conduction time and refractoriness by AA pacing. Different simulated models of slow/fast and fast/slow reentry were induced. SV caused inhibitory effects on the slow anterograde conduction (origin of refractoriness) more than on the fast anterograde conduction time, leading to an increase of tachycardia cycle length, tachycardia wavelength and termination of slow/fast reentrant tachyarrhythmia. Verapamil significantly suppressed the basic and frequency‐dependent intrinsic nodal properties. In addition, SV decreased the incidence of gap and echo beats. The present study showed that SV in a concentration and rate‐dependent manner increased the AV effective refractory period and reentrant tachycardia wavelength that lead to slowing or termination of experimental fast AVNRT. The direction‐dependent inhibitory effect of SV on the anterograde and retrograde dual pathways explains its specific antireentrant actions.     

射频消融的延迟效应对手术效果及并发症的影响

目的 :探讨射频消融延迟效应对手术效果及并发症的影响。方法 :回顾分析 1998～ 2 0 0 2年住院的室上速 4例 ,年龄 15～ 4 5岁 ,男女各 2例 ,其中房室结折返性心动过速 (AVNRT) 2例 ,右侧显性预激 (B- WPW) 2例 ,射频消融均未成功 ,在消融过程中 2例 B- WPW出现短暂旁路前传消失 ,2例 AVNRT出现短暂快速交界性心律及一过性 度房室传导阻滞。结果 :2例 B- WPW术后 1个月复查心电图预激消失 ,2例 AVNRT分别于术后 3d和 1周出现持续 度房室传导阻滞和 度 型房室传导阻滞 ,经激素治疗后房室传导均恢复正常。所有患者术后均未再发作室上速。结论 :射频消融术后组织及电学损伤范围可进一步加大从而产生延迟现象 ,它可对患者有益也可产生不利影响 ,因此射频消融时要密切注意可能产生延迟反应的电生理现象。