Pulsus Alternans Caused by 2:1 Left Bundle Branch Block

Pulsus alternans was caused by 2:1 left bundle branch block in a patient with a left ventricular ejection fraction of 50% and normal coronary arteries. The observations documented the profound depressant hemodynamic effect of complete left bundle branch block in the setting of minimal systolic left ventricular function.     

Total Masquerading Bundle Branch Block

We report a case of 82‐year‐old female with total masquerading bundle branch block. We discuss the problems with ECG analysis.     

The Surface Electrocardiogram Predicts Risk of Heart Block During Right Heart Catheterization in Patients With Preexisting Left Bundle Branch Block: Implications for the Definition of Complete Left Bundle Branch Block

LBBB and Heart Block . Background: Patients with left bundle branch block (LBBB) undergoing right heart catheterization can develop complete heart block (CHB) or right bundle branch block (RBBB) in response to right bundle branch (RBB) trauma. We hypothesized that LBBB patients with an initial r wave (≥1 mm) in lead V1 have intact left to right ventricular septal (VS) activation suggesting persistent conduction over the left bundle branch. Trauma to the RBB should result in RBBB pattern rather than CHB in such patients. Methods: Between January 2002 and February 2007, we prospectively evaluated 27 consecutive patients with LBBB developing either CHB or RBBB during right heart catheterization. The prevalence of an r wave ≥1 mm in lead V1 was determined using 118 serial LBBB electrocardiographs (ECGs) from our hospital database. Results: Catheter trauma to the RBB resulted in CHB in 18 patients and RBBB in 9 patients. All 6 patients with ≥1 mm r wave in V1 developed RBBB. Among these 6 patients q wave in lead I, V5, or V6 were present in 3. Four patients (3 in CHB group and 1 in RBBB group) developed spontaneous CHB during a median follow‐up of 61 months. V1 q wave ≥1 mm was present in 28% of hospitalized complete LBBB patients. Conclusions: An initial r wave of ≥1 mm in lead V1 suggests intact left to right VS activation and identifies LBBB patients at low risk of CHB during right heart catheterization. These preliminary findings indicate that an initial r wave of ≥1 mm in lead V1, present in approximately 28% of ECGs with classically defined LBBB, may constitute a new exclusion criterion when defining complete LBBB. (J Cardiovasc Electrophysiol, Vol. pp. 781‐785, July 2010)     

左束支区域起搏可改善右束支阻滞的心电图表现

目的:旨在观察左束支区域起搏(LBBAP)纠正右束支阻滞(RBBB)的临床效果及心电图特点.方法:本研究为单中心、前瞻性观察性研究,纳入2018年4月至2019年12月间入院有心室起搏指征,存在基线RBBB图形且QRS波群时限≥120 ms、左心室射血分数>50％并接受LBBAP的患者,分析LBBAP纠正RBBB的临床...     

急性心肌梗死合并完全性左束支传导阻滞的心电图诊断

当心肌梗死合并左束支阻滞时,心电图诊断变得困难.近半个世纪以来出现了一些针对这类患者的心电图诊断标准,现就此作一综述.     

Intermittent Left Bundle Branch Block and Myocardial Ischemia in Patient Without Coronary Artery Stenosis:A Case Report

Left bundle branch block （ LBBB ）, traditionally viewed as an electrophysiologic abnormality, is increasingly recognized for its effects on hemodynamics and patient＇s prognosis^[1]. Exercise nuclear studies frequently show reversible perfusion defects in the absence of obstructive coronary artery disease^[2] and some patients with intermittent LBBB develop angina coincident with the onset of LBBB^[3]. We report a case of intermittent LBBB with abnormal stress technetium 99m TC single-photon emission computed tomography （SPECT） study and normal coronary artery angiography.     

Cardiac Resynchronization Therapy Relieves Intractable Angina Due to Exercise‐Induced Left Bundle Branch Block Without Left Ventricular Systolic Dysfunction: A Detailed Case Study

Exercise‐induced left bundle branch block is rare and can be demonstrated with exercise testing. When the heart rate reaches a certain threshold, the QRS widens into left bundle branch block. This paper describes a patient with exercise‐induced left bundle branch block related angina and dyspnea, who responded to cardiac resynchronization therapy. We documented the potential benefits of cardiac resynchronization therapy with a left ventricular rapid pacing study prior to its implantation. Although exercise‐induced left bundle branch block is not a current indication for cardiac resynchronization therapy in patients such as ours, it could be considered when conventional drug therapy fails.     

Underuse of Thrombolytic Therapy in Acute Myocardial Infarction and Left Bundle Branch Block

Thrombolytic therapy reduces mortality in patients with acute myocardial infarction (AMI) and left bundle branch block (LBBB). The difficulty in accurately diagnosing AMI in patients with LBBB, however, might result in their undertreatment. Among 3,890 patients hospitalized with chest pain, 241 (6.2%) had LBBB at presentation. The only variable independently associated with AMI among patients with LBBB was in‐hospital left ventricular failure (odds ratio [OR]: 4.32, 95% confidence interval [CI]: 1.95–9.57, p < 0.0005). Only 16 (29%) of the LBBB patients with AMI received thrombolytic therapy compared with 583 (78%) of the 747 patients with ST‐elevation AMI (p < 0.0005). A further 19 (10%) LBBB patients without AMI also received thrombolysis. Difficulty in making an accurate early diagnosis in patients with LBBB ensures that the majority of those with AMI fail to receive thrombolytic therapy while others without AMI are treated inappropriately. Improved diagnostic and therapeutic strategies are needed for patients with acute coronary syndromes and LBBB. Copyright © 2010 Wiley Periodicals, Inc.     

Loss of Left Bundle Branch Block following Biventricular Pacing Therapy for Heart Failure: Evidence for Electrical Remodeling?

Cardiac resynchronization therapy has been proven to improve symptoms and indices of left ventricular function in patients with heart failure and intraventricular conduction delays. We present a case of a patient with New York Association Class III heart failure and left bundle branch block, who received a biventricular pacemaker in order to achieve cardiac resynchronization. Her symptoms improved markedly, as did left ventricular ejection fraction and dimensions. In addition, her intrinsic QRS duration normalized. This may represent a salutory effect of biventricular pacing on electrical remodeling.     

Catheter Ablation of the Left Bundle Branch for the Treatment of Sustained Bundle Branch Reentrant Ventricular Tachycardia

Sustained Bundle Branch Reentrant VT. Radiofrequency catheter ablation of the left bundle branch (LBB) was attempted in a patient with sustained bundle branch reentry. During sinus rhythm, the QRS had a complete LBB block pattern, and the LBB was activated retrogradely (transseptal). Ablation of the LBB eliminated inducibility of the tachycardia, while the QRS complex and the duration of the HV interval (70 msec) remained unchanged. Successful ablation of the LBB eliminated bundle branch reentry and yet maintained the anterograde conduction properties of the His-Purkinje system, obviating implantation of a permanent pacemaker.     

Bundle Branch Reentry Ventricular Tachycardia with Two Distinct Left Bundle Branch Block Morphologies

Bundle Branch Reentry VT with Two Morphologies. Introduction: Bundle branch reentry ventricular tachycardia (VT) is usually amenable to treatment with radiofrequency ablation. Different QRS morphologies during VT are possible when anterograde ventricular activation is over the left bundle branch. Manifestations of tbis reentrant tachycardia with more than one QRS morphology with anterograde activation via the right bundle have not been reported and would be unusual due to the more discrete anatomy of the right bundle branch. Methods and Results: An electropbysiologic study was conducted in a patient with dilated ventricle and diminished ventricular function with VT, Typical characteristics of bundle branch reentry were noted when VT was induced. The study was notable for the presence of a right bundle recording only during macroreentrant beats or VT and the distal location of the recording. Radiofrequency ablation was performed. Postablation stimulation again induced VT, proven to be of the same bundle branch reentry mechanism but of a different QRS morphology. A second ablation was required for complete ablation of this patient's bundle branch reentry VT. Conclusion: In bundle branch reentry utilizing the left bundle as the retrograde limb and the right bundle branch as the anterograde limb of the circuit, VT of more than one distinct morphology can be seen. Careful evaluation to assess for the persistence of VT of the same mechanism is necessary to ensure complete ablation of the reentrant circuit. Preexisting right bundle disease and a dilated heart with more dispersed distal right bundle branches may predispose to such a phenomenon.     

Typical ECG Changes Unmasked by Ajmaline in a Patient with Brugada Syndrome and Left Bundle Branch Block

Brugada syndrome is a channelopathy associated with right bundle branch block and ST segment elevation in the right precordial leads. These electrocardiographic signs may not be apparent most of the time but can be unmasked by certain antiarrhythmic agents. Until now, all of the reports on this syndrome have focused on patients with no significant intraventricular conduction delay at baseline electrograms. In this report, we describe a patient with Brugada syndrome with left bundle branch block at baseline ECG. After intravenous ajmaline, the patient developed right bundle branch block and ST segment elevations in the right precordial leads.     

Correlation between Electrocardiographic Features and Mechanical Dyssynchrony in Heart Failure Patients with Left Bundle Branch Block

Background: Few electrocardiographic parameters beyond the QRS duration were studied with regard to the correlation with mechanical dyssynchrony. This study aims to analyze the correlation between electrocardiographic parameters and mechanical dyssynchrony in patients with symptomatic heart failure (HF) and left bundle branch block (LBBB). Methods: Patients with HF, ejection fraction ≤ 35%, and QRS interval ≥ 120 ms with a LBBB were prospectively studied. We analyzed the correlation between electrocardiographic parameters (QRS duration, R voltage in limb leads, S voltage in precordial leads, Sokolow and Cornell indexes, QRS axis deviation, and QRS notches in lateral and inferior leads) and mechanical dyssynchrony measured by tissue Doppler imaging (TDI). Results: A group of 50 patients were studied, 60% male, 78% with nonischemic cardiomyopathy, NYHA Class III–IV (86%), and ejection fraction of 0.22 ± 0.6. Intra‐ and interventricular dyssynchrony occurred in 68% and 74% of patients, respectively. The S amplitude in precordial leads and the Sokolow and Cornel indexes show a weak correlation with the degree of dyssynchrony. In the patients with QRS notching in the lateral and inferior leads, we observed significantly greater prevalence of intraventricular dyssynchrony, with sensitivity and specificity of 85% and 56%, respectively, for notches in lateral leads. The QRS duration presents moderate correlation with the degree of both intraventricular (r = 0.48) and interventricular dyssynchrony (r = 0.46). Conclusion: The following electrocardiographic parameters were related to the degree of mechanical dyssynchrony: QRS duration and notches in QRS. In addition, the patients tend to have highest S amplitude in precordial leads. Ann Noninvasive Electrocardiol 2011;16(1):41–48