动态心电图显示房室结双径路心电现象分析

目的 探讨动态心电图揭示房室结双径路传导的心电图改变.方法 回顾性分析11例动态心电图诊断房室结双径路患者的心电图特征和特殊心电现象.结果 患者共11例,动态心电图均出现PR间期跳跃式延长,其中有4例表现为两种揭示房室结双径路存在的特征性心电现象:①房性早搏揭示房室结双径路7例.其中房性早搏的PR间期跳跃式延长诱发慢-...     

消融房室结慢径路导致窦性心律时的长PR间期恢复正常

房室结折返性心动过速(AVNRT)是以房室结双径路为基础的折返性室上性心动过速。大多数患者窦性心律时体表心电图的PR间期在正常范围。本文报道1例消融术前窦性心律时伴长PR间期的AVNRT患者，消融房室结慢径路后PR间期恢复正常。     

心电图PR间期延长精读

PR间期延长是一度房室阻滞的主要心电图表现。但PR间期延长不都是一度房室阻滞;PR间期延长不一定都能直接显现;过长的PR间期又易被误判为无房室传导关系;明确PR间期延长如何分析阻滞部位等,这些困惑的问题常影响一度房室阻滞的诊断,现结合临床病例分析讨论如下。     

心电图PR间期延长面面观

1概述心电图PR间期代表心脏的房室传导,通常是在0.12～0.20s之间,在心率缓慢的状态下,PR间期也不应超过0.21s。PR间期延长说明房室传导迟缓,它可以是房室传导阻滞,也可见于其他问题,PR间期延长可以揭示多种心电现象。     

房室结双径路特殊表现一例

患者常规体表心电图PP间期基本规则,PR间期不典型逐搏延长,随后突然出现一长RR间期,酷似二度Ⅰ型房室阻滞.通过24 h动态心电图可观察到长RR间期前的QRS波终末部出现一个逆行P-波,PR间期跳跃性延长达到0.15 s,提示存在房室结双径路.考虑为快径路一度房室阻滞,房室结双径路伴慢径路文氏阻滞和慢-快径路蝉联现象.     

房室结快、慢径路的正、反文氏现象伴慢-快径路蝉联现象

患者男,50岁,因反复发作性心前区堵塞感、气喘1年,近2 d再发就诊。动态心电图夜间记录可见规律出现P波,经历了3次房室传导跳跃现象和3次正文氏现象,2次反文氏现象,符合房室结快、慢径路的正、反文氏现象及慢-快径路蝉联现象。本例以多个心动周期PR间期〉0.35 s变化为主,周而复始,其中PR间期最长达0。64 s,长久出现将会影响到患者心脏功能;我们在动态心电图报告中应突出PR间期明显延长描述,以引起临床重视。     

RP／PR间期的对应性

心电图RP间期与PR间期的对应性表现了房室结生理性及病理性递减传导的特征。【定义】心电图中，随着RP间期的缩短，其后相应的PR间期将延长，这种随RP间期逐渐缩短，其后PR间期对应性延长的心电现象称RP，PR间期的对应性（RP，PR reciprocity）。     

传导速度与不应期

心脏特殊传导系统中传导速度快的组织不应期长，这一规律有时令人难以理解。 例如房室结常存在快慢两条径路，快径路的传导速度快，传导时PR间期短，相反，经慢径路传导时PR间期长。而快径路不应期长的几率为90％，房室结双径路引发的折返性心动过速中，90％为慢快型（慢径路前传，快径路逆传），     

房室结双径路动态心电图分析

房室结双径路传导(DAVNP)是一种易伴发假性一度房室阻滞及不典型文氏型房室阻滞、反复搏动、房室结折返心动过速等多种心律失常的心脏电生理现象(1).动态心电图监测时间较长,较常规的体表心电图采集的信息更为系统与完整.较易显示此现象,本文通过分析与房室结双径路有关的几种心电图表现,其目的是加深对其理解,并对阵发性P-R间期延长做出鉴别诊断.     

动态心电图对体表心电图P-R间期延长的诊断价值

目的 探讨动态心电图对体表心电图P．R间期延长的诊断价值,分析P—R间期延长的临床意义和预后。方法选择2008年1月至2011年8月在昆明医学院第二附属医院住院和门诊心电图有P-R间期延长的患者90例为研究对象．监测其动态心电图。分析P．R间期的变化及阵发性心房颤动、房室结双径路传导、第二度I型房室阻滞、间歇性左右束支阻滞4类心律失常。并且根据P—R间期延长程度分为3组,对比其与上述4类心律失常的关系。结果动态心动图结果中伴发第二度I型房室阻滞2l例（23．33％）、房室结双径路传导17例（18．89％）、间歇性左右束支阻滞9例（10％）、阵发性心房颤动7例（7．78％）。在所有的患者中,P．R间期延长伴发上述4类心律失常发生率为60％。心电图结果中,P-R间期延长50例,显著延长29例,过度延长11例。动态心动图结果中。P。R间期延长32例,显著延长38例,过度延长20例。结论P—R间期延长不应均视为良性和无须干预的心律失常,相反,需要进行进一步动态心动图监测及电生理检查和追踪观察,争取早期发现病变、消除病变,为临床早期诊断、早期治疗提供辅助手段。     

动态心电图显示房室结双径路及有关特殊心电现象

为探讨房室结双径路(DAVNP)在动态心电图直接显示的条件、主要诊断线索及与之有关的特殊心电现象,对 7例在动态心电图直接显示DAVNP的心电图特征和有关特殊心电现象进行了回顾性分析。结果: 7例患者的动态心电图均出现PR间期跳跃性的改变,并有蝉联现象及不典型文氏现象发生,呈DAVNP特征。结论:动态心电图中PR间期的跳跃性改变提示DAVNP的存在,为临床诊治提供更多的依据。     

Risk of development of delayed atrioventricular block after slow pathway modification in patients with atrioventricular nodal reentrant tachycardia and a pre-existing prolonged PR interval.

AIMS: The objective of this prospective study was to assess risk factors for the development of atrioventricular block following slow pathway modification in patients with atrioventricular nodal reentrant tachycardia and a pre-existing prolonged PR interval. METHODS AND RESULTS: Of 346 consecutive patients with atrioventricular nodal reentrant tachycardia undergoing slow pathway modification, 18 patients (62 +/- 7 years; five females) were found to have a prolonged PR interval prior to ablation. Total elimination of the functional slow pathway was assumed if the antegrade effective refractory period following slow pathway modification was longer than the cycle length of atrioventricular nodal reentrant tachycardia. To detect atrioventricular node conduction disturbances, 24-h Holter recordings were performed 1 day prior to slow pathway modification, and 1 day, 1 week, 1, 3 and 6 months after the procedure. Six patients developed late atrioventricular block. The incidence of delayed atrioventricular block following successful slow pathway modification was higher in patients with, compared to patients without, prolonged PR interval at baseline (6/18 vs 0/328, P < .001). In the former group, the antegrade effective refractory period was longer in patients with, compared to those without, a delayed atrioventricular block (492 +/- 150 ms vs 332 +/- 101 ms, P < 0.05). The incidence of delayed atrioventricular block was higher in patients with total elimination of the slow pathway compared to patients without (5/7 vs 1/11, P < 0.01). CONCLUSIONS: Slow pathway modification in patients with atrioventricular nodal reentrant tachycardia and a prolonged PR interval is highly effective. However, there is a significant risk of development of delayed atrioventricular block, particularly when the procedure results in total elimination of the slow pathway.     

短P—R综合征合并室上性心动过速的电生理观察

为探讨短Ｐ－Ｒ综合征合并室上性心动过速的电生理机制,对７例短Ｐ－Ｒ综合征合并室上性心动过速的患者进行心内电生理检查。结果发现：随着心房负扫描程序刺激,６例Ａ－Ｈ间期逐渐延长,１例间歇性延长,６例有Ａ－Ｈ间期跳跃现象;室上性心动过速时６例最早心房激动部位在希氏束,Ｖ－Ａ间期〈７０ｍｓ,１例在左后游离壁,Ｖ－Ａ间期〉７０ｍｓ。提示短Ｐ－Ｒ综合征合并室上性心劝过速的电生理机制是房室结加速传导合并房室结双     

Linking phenomenon in dual atrioventricular nodal pathways.

The linking phenomenon is an electrophysiological phenomenon of conduction between 2 different pathways, such as bundle branches, atrioventricular node (AVN) and accessory pathways. The present study used electrophysiological studies to investigate this phenomenon in 14 patients with dual AVN pathways. Decremental ramp pacing at intervals of 10 ms was carried out in high right atrium until the atrio-His (A-H) interval was abruptly prolonged (onset), then subsequent incremental ramp pacing at intervals of 10 ms proceeded until the A-H interval abruptly shortened (offset). The linking window (LW) was defined as the difference between the paced cycle lengths of the offset and the onset. The linking phenomenon occurred in 9 patients (64%). The onset depended on the functional refractory period of the fast pathway and once the linking was established in the dual pathways, the LW was related to the difference between the A-H interval immediately before and after the restoration of anterograde fast pathway conduction. These findings suggest that the linking phenomenon in dual AVN pathways occurs because of anterograde conduction block in the fast pathway and the subsequent concealed retrograde conduction of impulses propagated from the slow pathway.     

长PR房室结双径路的电生理特点和射频消融慢径的安全性

目的　探讨窦律时PR已延长 ( >2 0 0ms)的房室结双径路的电生理特点和慢径消融的安全性。方法　观察 11例长PR组患者的电生理特点和射频消融慢径对PR和AH等心内参数的影响 ,并与 3 3例正常PR组对照。结果　长PR组患者无房室结双径路 ,即AH跳跃现象较正常PR组更常见 ,心室刺激较正常PR组更易诱发心动过速。射频消融对两组患者PR和AH无影响。长PR组射频消融后 1:1房室和室房传导的最大频率减慢 ,房室结有效不应期延长。结论　结果提示 ,长PR房室结双径路具有不同于正常PR者的电生理和射频消融特点 ,射频消融慢径对这些患者是安全、有效的。     

Dual atrioventricular nodal pathways associated with a gap phenomenon in atrioventricular nodal conduction

A 67 year old man underwent electrophysiologic study for evaluation of syncope. During atrial pacing at a basic cycle length of 600 ms, atrial premature stimuli were introduced at progressively shorter coupling intervals. The graph of atrial coupling intervals versus corresponding His bundle responses revealed an abrupt increase in atrioventricular (AV) nodal conduction time with coupling intervals from 320 to 340 ms. In an atrial coupling interval of less than 320 ms, conduction was again rapid until the effective refractory period of the atrium was reached. These unique findings are compatible with dual pathways and a gap phenomenon within the AV node.     

Conduction system abnormalities in symptomatic mitral valve prolapse: An electrophysiologic analysis of 60 patients

This study examined the site of atrioventricular (AV) block in mitral valve prolapse (MVP). Sixty symptomatic patients with MVP underwent electrophysiologic study; 49 had documented arrhythmias and 28 had syncope. Eight patients had spontaneous second- or third-degree AV block and 10 had chronic bundle branch block. Electrophysiologic study revealed abnormal sinus node function in 8 patients, prolonged HV interval in 10, intra-Hisian delay in 9, and functional bundle branch block in 15. Dual AV nodal pathways were demonstrated in 24 patients. Comparison with 101 similarly symptomatic patients without MVP revealed a greater prevalence of dual AV nodal pathways in the MVP patients. Infranodal conduction abnormalities and dual AV nodal pathways are frequently revealed by electrophysiologic testing in symptomatic patients with MVP.     

ECG of the "newborn" mouse (Mus domesticus) with specific reference to comparative AV transmission

INTRODUCTION: The objective of this study was to record the ECG of the smallest living mammal to extend the domain of data for comparative AV nodal electrophysiologic purposes. These data are needed to establish the relationship between the PR interval and heart size in mammalian species of all sizes. METHODS AND RESULTS: In recently born mice (age 1.5 to 8 weeks) weighing between 2.5 and 10 g and with estimated heart weights between 15 and 60 mg, ECGs, using bipolar limb leads, were recorded during general anesthesia. The PR interval, representing AV transmission time was about 40 msec, which is quite long for hearts of this size. On the basis of detailed analysis of the data, we postulate the presence of a fixed delay or discontinuous propagation in the AV node not only in newborn mice, but in mammals of all sizes. CONCLUSION: AV transmission times obtained in mammals (including humans) cannot be explained on the basis of generally accepted, classic AV conduction theories. The acceptance of the presence of a fixed delay in the AV node may ultimately be of value to better understand AV node function during sinus rhythm and supraventricular arrhythmias.     

PR间期与二尖瓣返流和左心室充盈的关系

目的 探讨异常PR间期对舒张期和收缩期二尖瓣返流的影响及对左心室充盈的影响。方法 选择心房心室分离患者为模型，采用数字化超声心动图技术观察PR间期与二尖瓣返流及左心室舒张期前向血流充盈时间的关系。结果 PR延长达一定程度将引起二尖瓣舒张期返流，本例患者PR间期临界宽度为0．27S；在一定范围内PR越长则二尖瓣舒张期返流持续时间越长；PR越长，舒张期前向血流充盈时间越短。结论 PR延长是形成二尖瓣舒张期返流的重要条件；同时，PR延长使左心室充盈时间显著缩短。