窄QRS波群心动过速时ST-T改变的价值探讨

目的探讨窄QRS波群心动过速（NQRST）时ST-T改变对鉴别房室结折返性心动过速（AVNRT）与房室折返性心动过速（AVRT）的价值以及旁道位置的定位。方法观察100例NQRST者心电图ST段压低的部位、程度以及T波倒置等情况。结果AVRT的ST段压低〉2mm且持续≥100ms,ST段压低幅度均显著大于AVNRT,左侧游离壁旁道ST段压低的导联多见于V1～6导联。结论ST-T改变有助于AVNRT和AVRT的鉴别和旁道位置的初步定位。     

顺向型房室折返性心动过速与慢快型房室结折返性心动过速的分析与鉴别（1）

阵发性室上性心动过速以顺向型房室折返性心动过速（AVRT）和慢快型房室结折返性心动过速（AVNRT）最常见,通常阵发性室上性心动过速即指这两种类型的心动过速。由于两者在QRS形态和频率方面相似,R—P-间期均〈P-R间期,有时鉴别较为困难。但详细分析各自的电生理特征和心电图改变仍可明确诊断,通过对顺向型AVRT的P波形态分析,甚至可对房室旁道作出初步定位诊断。     

窄QRS波群室上性心动过速时ST-T改变的临床意义

目的观察ST-T改变对窄QRS波群房室折返性心动过速(AVRT)与房室结折返性心动过速(AVNRT)的鉴别诊断及旁道初步定位的作用。方法分析150例窄QRS波群心动过速患者发作时ST段压低程度及持续时间、T波倒置等情况。结果诊断为AVNRT55例,AVRT95例。ST段压低≥2mm且持续≥100ms者AVRT组(51例,53.68%)多于AVNRT组(15例,27.27%),ST段压低幅度AVRT组(1.58±1.35mm)大于AVNRT组(0.71±0.67mm),心房间传导时间AVRT组(81.02±32.47ms)长于AVNRT组(33.30±13.56ms),差异均有显著性意义(P均<0.05)。ST段压低导联分布左侧游离壁旁道者多见于V3～V6,左后间隔和右后间隔者多见于Ⅱ、Ⅲ、aVF,右侧游离壁旁道者无特异性。结论窄QRS波群室上性心动过速时ST段改变可作为区分AVRT与AVNRT的指标,且有初步旁道定位价值。     

房室折返性心动过速的特殊心电现象分析

房室折返性心动过速的特殊心电现象分析施冰唐艳红王跃岭陈芳王晋明许家唐其柱左进周纪宁房室旁道（ＡＰ）参与的房室折返性心动过速（ＡＶＲＴ）是最常见的阵发性室上性心动过速（ＰＳＶＴ），其心电图和食管电生理特征典型者，诊断较容易。但若合并有房室结双径（ＤＡ...     

房室旁道合并房室结双径路形成的窄QRS波群心动过速

阵发性室上性心动过速中最常见的类型为房室旁道参与折返形成的顺向性房室折返性心动过速（AVRT）和房室结双径路折返引起的慢快型房室结折返性心动过速（AVNRT）,两者均为窄QRS波群,心动过速频率又比较接近,有时较难鉴别。尤其隐匿性房室旁道合并存在房室结双径路者,因窦性心律时无心室预激表现,     

经食管心脏电生理检查误诊房室折返性心动过速的不典型房室结折返性心动过速的特点及分析

目的探讨食管电生理检查中被误诊为房室折返性心动过速的不典型的慢快型房室结折返性心动过速的特点。方法回顾性分析5例误诊为房室折返性心动过速患者的食管电生理及心内电生理资料。结果 5例患者在食管电生理检查S1S2程控期前刺激中,均未观察到S2-R间期有跳跃性延长,心动过速的R-P-EB间期70ms;逆行P-波在V1导联直立,下壁导联倒置;食管电生理诊断为左后间隔隐匿性旁道参与的房室折返性心动过速。心内电生理诊断为慢快型房室结折返性心动过速,并成功消融慢径路。结论部分R-P-EB间期70ms的不典型慢快型房室结折返性心动过速食管电生理特点与后间隔隐匿性旁道参与的房室折返性心动过速类似,必要时需心内电生理检查加以明确。     

经食管心房调搏诱发及终止预激综合征房室折返性心动过速的研究

目的探讨经食管心房调搏诱发和终止预激综合征阵发性房室折返性心动过速的价值.方法对30例预激综合征患者行食管心房调搏程控刺激.结果经食管心房调搏对房室折返性心动过速的诱发率,典型预激综合征A型与B型差异无显著意义(P＞0.05),典型预激综合征与詹姆斯型预激综合征差异则有非常显著意义(P＜0.05).心房刺激诱发顺向型房室折返性心动过速的关键因素是旁道有效不应期大于房室交接区有效不应期.结论典型预激综合征的类型对诱发房室折返性心动过速无明显影响;诱发的关键因素是旁道有效不应期大于房室交接区有效不应期;猝发法是终止发作的最有效方法之一,转复成功率接近100%.     

以阵发性发作为特征的房室慢旁路参与的房室折返性心动过速

目的研究以阵发性发作为特征的房室慢旁路参与的房室折返性心动过速。方法21例病例资料来自1999年7月至2005年1月间在北京大学人民医院接受射频消融治疗的患者,均符合房室慢旁路的诊断标准,根据其心动过速发作的频繁程度分为阵发组和持续组两组,对比分析其电生理资料。结果与持续组相比,阵发组房室慢旁路逆传不应期较长[(359±46)ms对(318±31)ms,P<0.01]、文氏点较低[(133±18)/min对(165±22)/min,P<0.05],这种差别与慢旁路所在部位无关。结论房室慢旁路逆传不应期延长、文氏点降低是其参与的房室折返性心动过速呈阵发性发作的原因。     

体表心电图对房室结折返性与房室折返性心动过速的鉴别诊断

为探讨体表心电图对房室结折返性和房室折返性心动过速的鉴别诊断价值,对以射频导管消融、心脏电生理检查、心外膜标测的方法确诊房室结折返性心动过速(AVNRT)和房室折返性心动过速(AVRT)的88例患者的室上性心动过速发作时心电图作对照研究。结果显示:(1)P'波出现率在AVNRT占33％,在AVRT占100％(P<0.01)。(2)R-P'间期<80ms时常见于AVNRT,而≥80ms多见于AVRT(P<0.01)。(3)AVNRT在下壁导联(Ⅱ、Ⅲ、aVF)常见假性S波,而V_1导联常合并假性r波。(4)AVRT无文氏现象,但常出现束支传导阻滞改变且符合Coumel-Slama定律。认为以上特点对两者鉴别诊断有重要价值。     

房室结折返性心动过速的发作方式及射频消融终点研究

房室结折返性心动过速（AVNRT）是阵发性室上性心动过速（简称室上速）最常见的类型，约占阵发性室上速的50％。而房室结双径路（DAVNP）被认为是发生房室结折返性心动过速的基础。典型房室结折返性心动过速患者的房室结传导曲线（AVNFC）呈“跳跃”状态，然而，近年发现在AVNFC呈非跳跃性的患者也可发生AVNRT。可见房室结结构及其电生理特性极其复杂，本文对房室结折返性心动过速不同的发作方式及房室结传导曲线本质特点、射频消融治疗终点进行综述。     

AV Nodal-His-Purkinje Reentry: A Novel Form of Tachycardia

AV Nodal-His-Purkinje Reentry. Introduction: Bundle branch reentry (BBR) typically occurs in patients with dilated cardiomyopathy and infra-Hisian conduction system disease. The macroreentrant circuit of BBR is confined to the His-Purkinje system (HPS) and ventricular myocardium. As such, the atrioventricular (AV) node plays no role in the tachycardia circuit. Methods and Results: In the present study, we identified a novel form of wide complex tachycardia in a patient with coronary disease and severe aortic regurgitation. The tachycardia morphology was right bundle branch block with a left superior axis. Ventriculoatrial block was present during tachycardia. An unusual feature of this rhythm was two sequential His-bundle deflections (H and H′) for each ventricular beat of tachycardia. The H′V interval was identical to the HV interval during supraventricular rhythm. Changes in the ventricular cycle length (VV) preceded changes in the HH interval, consistent with retrograde activation of the first His-bundle deflection. Changes in the H ‘H’interval preceded changes in the VV interval, consistent with anterograde activation of the second His-bundle deflection. Tachycardia could be terminated with ventricular extrastimuli that did not capture the proximal HPS as well as with ventricular extrastimuli that advanced the His deflection, consistent with block in the HPS and in the AV node, respectively. Reproducible termination of the tachycardia following the first His deflection was demonstrated with adenosine, consistent with an upper pivot in the AV node. Conclusions: We have identified a new form of reentrant tachycardia in which the AV node, HPS, and ventricular myocardium each obligatorily participates in the tachycardia circuit, with the left posterior fascicle and right bundle functioning as the anterograde and retrograde limbs, respectively. Unlike BBR, however, the His bundle is activated twice as the wavefront pivots in the AV node. This model requires longitudinal dissociation at the levels of the AV node and His bundle.     

Atrioventricular nodal reentry tachycardia: Electrophysiologic comparisons in patients with and without 2:1 infra-his block

Patients with atrioventricular nodal reentry tachycardia (AVNRT) occasionally may demonstrate a 2:1 infra-His block during tachycardia. However, the electrophysiologic background of this phenomenon has not been established so far. In the present study we compared the electrophysiologic parameters of 10 consecutive patients with a transient 2:1 infra-His block during AVNRT of the common type (Group A) with those of 17 consecutive patients without this phenomenon during tachycardia (Group B). Transient 2:1 infra-His block occurred without termination of the tachycardia in all 10 patients of Group A. The tachycardia sustained despite intermittent or permanent conduction disturbance of the infrahisian tissue in 8 of these 10 patients. In comparison, the electrophysiologic parameters of 17 patients without 2:1 block during AVNRT of the common type (Group B) were analyzed. A significantly longer antegrade (318±58 ms vs. 259±50 ms) and retrograde (308±59 ms vs. 239±20 ms) AV conduction capacity could be demonstrated in these patients. The tachycardia cycle length did not differ significantly between the two groups, although the mean tachycardia cycle length was 48 ms longer in patients of Group B. These observations demonstrate an advanced conduction capacity in patients with a transient infra-His block during AVRNT of the common type. This study underlines that the reentry circuit in AVNRT is not necessarily dependent on infrahisian tissue.     

Late occurrence of heart block after radiofrequency catheter ablation of the septal region: clinical follow-up and outcome

INTRODUCTION: There are few data regarding the occurrence of delayed heart block at least 24 hours after radiofrequency catheter ablation (RFCA) of AV nodal reentry or posteroseptal accessory pathways (APs). We investigated the late occurrence of heart block in this population, the clinical outcome, and whether findings at electrophysiologic study could have predicted its development. METHODS AND RESULTS: Two of 418 patients with AV nodal reentry undergoing RFCA using a posterior approach and 1 of 54 patients with RFCA of a posteroseptal AP developed late heart block. Anterograde and retrograde AV nodal conduction before and after RFCA were normal. Patients received 12, 15, and 32 RFCA lesions, respectively, using a mean maximum power of 44 W. The RFCA sites were the posterior septum for posteroseptal AP and the posterior and mid-septum for patients with AV nodal reentry, with no His electrogram ever recorded at the ablation site. During RFCA, junctional tachycardia occurred with 1:1 VA conduction in the patient with a posteroseptal AP, but occasional intermittent single retrograde blocked complexes were present in both patients with AV nodal reentry. No rapid junctional tachycardia or >1 consecutive retrograde blocked complex was ever observed during RFCA. Persistent high-degree AV block with junctional escape developed 2 days after RFCA in the posteroseptal AP patient. A permanent pacemaker was implanted, and normal conduction was noted 16 days after RFCA. Both patients with AV nodal reentry complained of fatigue, mainly on exertion, 3 to 4 days after RFCA, and ECG-documented exercise-induced variable AV block was obtained. Because heart block resolved in our initial patient, a prolonged monitoring period was allowed. Symptoms disappeared at 13 and 8 days, and a follow-up treadmill test showed normal PR interval and no heart block. No recurrence of heart block has been seen in any of these three patients. CONCLUSION: Late unexpected heart block after RFCA of AV nodal reentry and posteroseptal AP is rare, often resolves uneventfully in 1 to 2 weeks, and no specific electrophysiologic findings predicted its occurrence. Prolonged clinical observation is preferable to immediate pacemaker implantation in such patients.     

"AV Nodal" Reentry:

"AV Nodal" Reentry. This review is the first of a two-part series of articles on "atrioven-tricular [AV] nodal reentry," The early clinical literature as well as the experimental studiesare reviewed, and more recent morphologic data are presented, with the aim of clarifyingwhether the reentrant circuit is contined to the AV node, or consists in part of extranodal components. Most of the evidence supports the concept that atrial tissue is an essential link in thereentrant pathway. Arguments will be presented to indicate that within the AV node, the separation between antegrade and retrograde pathways is functional, not anatomical, and that bothpathways are in electrotonic contact.     

Right septal macroreentrant tachycardia late after mitral valve repair: Importance of surgical access approach

BACKGROUND: Reentrant atrial tachycardias may occur after mitral valve surgery. These usually involve the left atrium or the lateral wall of the right atrium around the atriotomy scar. OBJECTIVE: The purpose of this study was to test whether ablation could eliminate atrial tachycardia after mitral valve repair. METHODS: Three patients (two men, one woman; mean age 57 +/- 12 years) were studied 48 +/- 38 months after mitral valve repair. In all cases, the surgical approach involved a transseptal incision. Tachycardia mapping was performed using multipolar catheters and the three-dimensional electroanatomic mapping system. The mean flutter cycle length was 313 +/- 21 ms. All patients had dual-loop reentry with one circuit around a septal scar and the other circuit around the tricuspid annulus. RESULTS: Successful radiofrequency ablation of the septal circuit was performed between the scar and the superior tricuspid annulus in all three cases. CONCLUSION: After mitral valve repair using a transseptal incision, dual-loop reentry may occur around the septal scar and the tricuspid annulus. Successful ablation may be achieved with an ablation line between the scar and the tricuspid annulus.     

Helical representation of atrial reentry: a teaching aid for electrophysiology

Cardiac clinical electrophysiology is difficult to teach because it requires mental integration of complex information on cardiac activation, which includes tridimensional spatial orientation of the cardiac structures involved and variables such as refractory period, conduction velocity, and cycle length. Commonly used representations of cardiac arrhythmias include snapshot sequences or ladder diagrams. The former lack time dimension, and the latter lack spatial dimension. We propose a schematic tridimensional representation of reentry as a helicoidal shape that is the result of adding a time dimension to a circular representation. This presentation, which also can be called a "loop diagram," allows better integration of spatial phenomena with recorded electrogram sequences and can help the teaching of basic clinical electrophysiology.     

Cure of Interfascicular Reentrant Ventricular Tachycardia by Ablation of the Anterior Fascicle of the Left Bundle Branch

Ablation of Interfascicular Reentrant Tachycardia. Introduction: Fascicular reentrant ventricular tachycardia (VT) using the anterior fascicle of the left bundle anterogradely is rare and may produce identical QRS morphology during sinus rhythm and VT. Catheter ablation of this type of VT has not been described in detail.
Methods and Results: In a postinfarct patient with dilated left ventricle and recurrent VT (showing a QRS configuration of right bundle branch, left posterior fascicular block), endocardial recordings from the His-Purkinje system showed that VT was due to interfascicular reentry. Induction of VT occurred after progressive retrograde conduction delay on increasing the prematurity of the extrastimulus. Anterograde conduction occurred exclusively over the left anterior fascicle, which caused identical QRS morphology during sinus rhythm and VT. During VT, the left posterior fascicle was used retrogradely. The usual target for bundle branch reentry ablation, the right bundle, did not participate in the reentrant circuit. While performing left ventricular endocardial mapping, VT was interrupted when positioning the catheter on the left anterior fascicle, and "reversed" nonsustained bundle branch reentry occurred with anterograde conduction over the posterior fascicle and retrograde conduction over the anterior fascicle. Ablation of conduction in the anterior fascicle led to cure of the VT.
Conclusion: Interfascicular reentrant VT with right bundle branch block, right-axis QRS configuration can be cured by catheter ablation of anterior fascicle conduction.