Repetitive supernormal conduction in the right bundle branch in high degree bilateral bundle branch block

Electrocardiograms were taken from a 67-year-old woman with high-degree atrioventricular block in which ventricular escape beats of right bundle branch block pattern occurred, accompanying occasional ventricular capture beats. Only when a sinus P wave occurred 0.60 s after the preceding escape beat, it was followed by a capture beat of left bundle branch block pattern with the RP interval of 0.60 s and the PR interval of 0.19 s. Similar left bundle branch block with left axis deviation pattern had been shown in the electrocardiogram taken 2 years before. Such RP and PR intervals in capture beats were invariable. These suggest that capture beats occurred as a result of supernormal conduction in the right bundle branch, which denies the possibility of ventricular extrasystoles. Such capture beats with the above RP and PR intervals were observed repeatedly.     

Mechanisms influencing conduction in a case of intermittent bundle branch block

A case study of the phenomenon of intermittent left bundle branch block has been presented. We tested a variety of physiologic maneuvers and pharmacologic agents for their effects on intraventricular conduction. The data indicated that heart rate could not have been the primary determinant of the type of intraventricular conduction, but may have had a secondary or modifying influence. Carotid sinus pressure was shown to both terminate and induce bundle branch block. The form of the ventricular complex during carotid sinus pressure was related to the degree of prolongation of the R-R interval. It could not be determined from our data whether the response to increased vagal tone was due to direct inhibitory effect of the vagus or to other factors, such as the marked fall in mean arterial blood pressure. The effects of the various physiologic maneuvers suggest that hemodynamic factors may play a major role in determining the form of the ventricular complex. The responses to the various pharmacologic agents tested seemed to indicate that the diseased bundle was extremely sensitive to influences primarily altering intraventricular conductivity.In conclusion, after a careful analysis of studies performed on a patient with intermittent left bundle branch block, we still do not know which factor(s) was (were) most important in governing the mode of intraventricular conduction. It appears that heart rate can be eliminated as a primary factor in this patient. Perhaps the final answer to this problem lies in a better understanding of the interaction of hemodynamic, neural, and nutritional factors on intraventricular conduction.     

Site of conduction delay in children with catheter-induced right bundle branch block

Eight cases of catheter-induced right bundle branch block (RBBB) in children during electrophysiologic studies are presented. Recording of right ventricular apical activation time (V-RVA) before and during the conduction delay allowed localization of the block along the course of the right bundle branch system. In the majority of patients, a significant lengthening of V-RVA was observed, indicating that proximal right bundle branch block is the most commonly induced type of conduction delay. Block was transient in all patients and terminated several minutes to 24 hours after its induction.     

Left-sided intraventricular conduction delay concealed by right bundle branch block

The electrocardiograms of a 69-year-old woman with severe heart failure showed a left-sided nonspecific intraventricular conduction delay (QRS duration, 0.13 seconds) characterized by notches and slurrings in the descending part of the R waves in the left precordial leads and in the ascending parts of the S waves in the right precordial leads. Subsequently, a complete right bundle branch block with wider QRS complexes (0.17 seconds) appeared. It is possible to consider that the left-sided nonspecific intraventricular conduction delay was concealed by the greater conduction delay occurring when the complete right bundle branch block was present. This would be in keeping with a previous study using Doppler tissue imaging in which this was postulated but where the corresponding electrocardiograms were not shown.     

Left bundle branch block with intermittent right axis deviation Evidence for left posterior hemiblock accompanying predivisional left bundle branch block

A case of complete left bundle branch block with several episodes of intermittent marked right axis deviation is presented. All possible causes of the intermittent development of additional right axis deviation, such as electrolyte imbalances, lateral wall infarct, intermittent Wolff-Parkinson-White conduction, right bundle branch block, right ventricular hypertrophy and pulmonary embolism, were excluded. We conclude that the explanation for left bundle branch block with intermittent right axis deviation in our patient was the coexistence of left posterior hemiblock and predivisional left bundle branch block.     

左束支起搏对合并右束支传导阻滞患者的心电学影响

目的探讨左束支起搏对症状性心动过缓合并右束支传导阻滞患者的心电学影响。 方法连续纳入2019年1月1日至2021年12月31日因症状性心动过缓合并完全性右束支传导阻滞并在厦门大学附属心血管病医院心内科拟行左束支起搏的患者,记录标准12导联体表心电图。比较左束支起搏术前与术后V₁导联QRS波形态、QRS时限、右心室延迟激动时间（dRVAT）、左心室达峰时间（LVAT）及心室间延迟时间（IVD）的差异。 结果共入选53例患者,年龄（72.15±9.39）岁,男34例。其中46例（86.79%,46/53）成功完成左束支起搏。术前V₁导联以rsR’型为主38例（38/46,83%）,术后QRS形态以Qr型为主29例（29/46,63%）。左束支起搏可以显著缩短QRS时限［（149.09±12.81）ms对（112.46±9.64）ms,P<0.001）］,其中35例（76.08%,35/46）患者的QRS时限完全纠正,10例（21.73%,10/46）部分纠正,1例（2.17%,1/46）未纠正;IVD显著缩短［（58.28±12.54）ms对（34.34±8.87）ms,P<0.001］;但在dRVAT方面左束支起搏术前与术后差异无统计学意义［（100.47±12.40）ms对（100.86±10.57）ms,P=0.955］。与术前相比,左束支起搏延长LVAT［（42.46±6.95）ms对（66.53±10.83）ms,P<0.001］。 结论左束支起搏可显著缩短完全性右束支传导阻滞患者的QRS时限,并改善其心室间电学同步性,产生以Qr型为主的起搏后QRS波形态。     

Intermittent tachycardia-dependent combined right bundle branch and left anterior conduction block

A patient is described who had intermittent tachycardia-dependent combined right bundle branch and left anterior conduction block (left axis deviation) with simultaneous onset and disappearance during observations extending over 15 months. Although the site of conduction block could not be definitely determined the pathologic and electrophysiologic data suggest that there was a lesion in the distal part of the His bundle, presumably in fibers already arranged and predestined to supply the right bundle branch and left anterior areas. A single lesion at the so-called pseudobifurcation or two separate lesions with similar electrophysiologic consequences could also account for the observations.     

间歇性完全性左束支阻滞13例分析

目的分析间歇性完全左束支阻滞(CLBBB)病例的临床特点。方法回顾分析13例12导联动态心电图检出间歇性完全左束支阻滞患者的病因、动态心电图、超声心动图、冠状动脉造影结果。结果 60岁以上患者12例,占92%。病因以冠心病、高血压、扩张型心肌病多见。本组冠脉造影及冠状动脉螺旋CT血管成像的7例间歇性完全性左束支阻滞患者中确诊为冠心病者3例。超声心动图结果:53.8%患者心房增大或心房心室同时增大。动态心电图检查可见间歇完全左束支阻滞常合并各种类型心律失常。结论间歇完全性左束支阻滞常发生在老年患者,常见于器质性心脏病,尤其是冠心病、高血压、扩张型心肌病。     

Auriculo-Hisian conduction of patients with bundle branch block. Clinical significance

The clinical and electrophysiological data in 52 consecutive patients with bundle branch block and followed-up for an average period of 20.8 +/- 10.4 months was reviewed. The patients were divided into two groups: Group A with normal AH intervals (36 patients) and Group B with prolonged AH intervals (16 patients). These two groups differed in age, the average being higher in Group B (p < 0.05), in history of syncope (more common in Group A: p < 0.01) and in the duration of PR interval (p < 0.05). On electrophysiological investigation the Wenckebach point was lower in Group B (118 +/- 29 ms) than in Group A (160 +/- 33) (p < 0.001). The effective right atrial refractory period was significantly longer in Group B (321 +/- 111 ms) than in Group A (246 +/- 59 ms) (p < 0.05). The effective refractory period of the atrioventricular node was also significantly longer in Group B (492 +/- 190 ms) than in Group A (333 +/- 125 ms (p < 0.05). On the other hand, there was no significant difference in the HV interval or in the number of patients managed by permanent pacing.     

完全性左束支阻滞和右束支阻滞心电图结果分析

目的 了解完全性左束支阻滞和右束支阻滞不同性别、不同年龄的发生率情况.方法 分析108 610例常规心电图检测结果,分别统计完全性左束支阻滞和右束支阻滞不同性别、不同年龄的发生率情况.结果 108 610例门诊及住院患者资料,完全性左束支阻滞19例,占0.18％;右束支阻滞3 794例,占3.49％;完全性左束支阻滞发生率在不同性别之间差异无统计学意义（Х^2=1.707,P=0.191）,不同年龄之间比较差异有统计学意义（Х^2=209.874,P＜0.05）;右束支阻滞发生率在不同性别之间、不同年龄之间比较,差异均有统计学意义（Х^2=986.046,P＜0.05;Х^2=1 483.286,P＜0.05）.结论 60岁以上老年人的完全性左束支阻滞和右束支阻滞发生率较高,应定期进行常规心电图检查,及时发现异常情况并进行相应的处理.     

Transient unifascicular, bifasicular and trifascicular block: electrophysiologic correlations in a patient with rate-dependent left bundle branch block and transient right bundle branch block.

Correlations of the His to ventricular (H-V) conduction time were made with the surface electrocardiogram during normal intraventricular conduction, unifascicular block (right bundle branch block), bifascicular block (left bundle branch block) and trifascicular block (right and left bundle branch block) in a patient with rate-dependent left bundle branch block who had transient right bundle branch block during recording of the His bundle electrogram. The results provide a functional confirmation of the theory that a prolonged H-V time is a manifestation of trifascicular disease.