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Current Cardiology Reviews 2021RBBB, a pattern seen on the 12-lead ECG, results when normal electrical activity in the His-Purkinje system is interrupted for some reason. The normal sequence of... (Review)
Review
RBBB, a pattern seen on the 12-lead ECG, results when normal electrical activity in the His-Purkinje system is interrupted for some reason. The normal sequence of activation is altered in RBBB, with a resultant characteristic appearance on the ECG manifest by a widened QRS complex and changes in the directional vectors of the R and S waves. This ECG pattern is often seen in clinical practice and generally regarded as benign. The anatomy, epidemiology, causes, symptoms, ECG findings and diagnosis, differential diagnosis in ECG, treatment, complications, prognosis, with respect to RBBB are outlined here, demonstrating some typical ECGs of RBBB.
Topics: Bundle-Branch Block; Electrocardiography; Female; Humans; Male
PubMed: 32640959
DOI: 10.2174/1573403X16666200708111553 -
Annals of Noninvasive Electrocardiology... Mar 2019In left bundle branch block (LBBB), the ventricles are activated in a sequential manner with alterations in left ventricular mechanics, perfusion, and workload resulting... (Review)
Review
In left bundle branch block (LBBB), the ventricles are activated in a sequential manner with alterations in left ventricular mechanics, perfusion, and workload resulting in cardiac remodeling. Underlying molecular, cellular, and interstitial changes manifest clinically as changes in size, mass, geometry, and function of the heart. Cardiac remodeling is associated with progressive ventricular dysfunction, arrhythmias, and impaired prognosis. Clinical and diagnostic notions about LBBB have evolved from a simple electrocardiographic alteration to a critically important finding affecting diagnostic and clinical management of many patients. Advances in cardiac magnetic resonance imaging have significantly improved the assessment of patients with LBBB and provided additional insights into pathophysiological mechanisms of left ventricular remodeling. In this review, we will discuss the epidemiology, etiologies, and electrovectorcardiographic features of LBBB and propose a classification of the conduction disturbance.
Topics: Aged; Bundle-Branch Block; Cardiac Resynchronization Therapy; Electrocardiography; Female; Humans; Magnetic Resonance Imaging, Cine; Male; Middle Aged; Prognosis; Risk Assessment; Severity of Illness Index; Treatment Outcome; Vectorcardiography
PubMed: 29932265
DOI: 10.1111/anec.12572 -
Europace : European Pacing,... May 2022The purpose of our study was to evaluate the feasibility and efficacy of cardiac resynchronization therapy (CRT) via left bundle branch pacing (LBBP-CRT) compared with... (Observational Study)
Observational Study
Cardiac resynchronization therapy via left bundle branch pacing vs. optimized biventricular pacing with adaptive algorithm in heart failure with left bundle branch block: a prospective, multi-centre, observational study.
AIMS
The purpose of our study was to evaluate the feasibility and efficacy of cardiac resynchronization therapy (CRT) via left bundle branch pacing (LBBP-CRT) compared with optimized biventricular pacing (BVP) with adaptive algorithm (BVP-aCRT) in heart failure with reduced left ventricular ejection fraction ≤35% (HFrEF) and left bundle branch block (LBBB).
METHODS AND RESULTS
One hundred patients with HFrEF and LBBB undergoing CRT were prospectively enrolled in a non-randomized fashion and divided into two groups (LBBP-CRT, n = 49; BVP-aCRT, n = 51) in four centres. Implant characteristics and echocardiographic parameters were accessed at baseline and during 6-month and 1-year follow-up. The success rate for LBBP-CRT and BVP-aCRT was 98.00% and 91.07%. Fused LBBP had the greatest reduced QRS duration compared to BVP-aCRT (126.54 ± 11.67 vs. 102.61 ± 9.66 ms, P < 0.001). Higher absolute left ventricular ejection fraction (LVEF) and △LVEF was also achieved in LBBP-CRT than BVP-aCRT at 6-month (47.58 ± 12.02% vs. 41.24 ± 10.56%, P = 0.008; 18.52 ± 13.19% vs. 12.89 ± 9.73%, P = 0.020) and 1-year follow-up (49.10 ± 10.43% vs. 43.62 ± 11.33%, P = 0.021; 20.90 ± 11.80% vs. 15.20 ± 9.98%, P = 0.015, P = 0.015). There was no significant difference in response rate between two groups while higher super-response rate was observed in LBBP-CRT as compared to BVP-aCRT at 6 months (53.06% vs. 36.59%, P = 0.016) and 12 months (61.22% vs. 39.22%, P = 0.028) during follow-up. The pacing threshold was lower in LBBP-CRT at implant and during 1-year follow-up (both P < 0.001). Procedure-related complications and adverse clinical outcomes including heart failure hospitalization and mortality were not significantly different in two groups.
CONCLUSIONS
The feasibility and efficacy of LBBP-CRT demonstrated better electromechanical resynchronization and higher clinical and echocardiographic response, especially higher super-response than BVP-aCRT in HFrEF with LBBB.
Topics: Algorithms; Bundle of His; Bundle-Branch Block; Cardiac Resynchronization Therapy; Electrocardiography; Heart Failure; Humans; Prospective Studies; Stroke Volume; Treatment Outcome; Ventricular Function, Left
PubMed: 34718539
DOI: 10.1093/europace/euab249 -
Journal of the American College of... Aug 2018Traditional right ventricular (RV) pacing for the management of bradyarrhythmias has been pursued successfully for decades, although there remains debate regarding... (Review)
Review
Traditional right ventricular (RV) pacing for the management of bradyarrhythmias has been pursued successfully for decades, although there remains debate regarding optimal pacing site with respect to both hemodynamic and clinical outcomes. The deleterious effects of long-term RV apical pacing have been well recognized. This has generated interest in approaches providing more physiological stimulation, namely, His bundle pacing (HBP). This paper reviews the anatomy of the His bundle, early clinical observations, and current approaches to permanent HBP. By stimulating the His-Purkinje network, HBP engages electrical activation of both ventricles and may avoid marked dyssynchrony. Recent studies have also demonstrated the potential of HBP in patients with underlying left bundle branch block and cardiomyopathy. HBP holds promise as an attractive mode to achieve physiological pacing. Widespread adaptation of this technique is dependent on enhancements in technology, as well as further validation of efficacy in large randomized clinical trials.
Topics: Arrhythmias, Cardiac; Bundle of His; Bundle-Branch Block; Cardiac Pacing, Artificial; Cardiac Resynchronization Therapy; Cardiac Resynchronization Therapy Devices; Electrocardiography; Humans
PubMed: 30115232
DOI: 10.1016/j.jacc.2018.06.017 -
Turk Kardiyoloji Dernegi Arsivi : Turk... Jun 2023Left bundle branch block-induced cardiomyopathy is an increasingly recognized type of dilated cardiomyopathy identified in a minority but not negligible proportion of... (Review)
Review
Left bundle branch block-induced cardiomyopathy is an increasingly recognized type of dilated cardiomyopathy identified in a minority but not negligible proportion of patients with newly diagnosed heart failure. However, it has not yet been included among the possible etiologies of dilated cardiomyopathies or among the unclassified cardiomyopathies. Although a few sets of diagnostic criteria have been proposed, currently there is a lack of universal consensus regarding diagnostic criteria. Some specific clinical features and electrocardiography, echocardiography, and cardiac magnetic resonance imaging findings are recommended to help physicians in the diagnosis of left bundle branch block-induced cardiomyopathy. In this review, prevalence, pathophysiological mechanisms, diagnostic criteria, diagnostic modalities, and specific features of left bundle branch block-induced cardiomyopathy have been addressed with attention to the differential diagnosis of other dilated cardiomyopathies.
Topics: Humans; Bundle-Branch Block; Cardiomyopathy, Dilated; Cardiomyopathies; Electrocardiography; Echocardiography; Arrhythmias, Cardiac
PubMed: 37272151
DOI: 10.5543/tkda.2023.06737 -
Annals of Noninvasive Electrocardiology... Jul 2022Complete right bundle branch block (CRBBB) is an important predictor of atrial fibrillation (AF) recurrence after pulmonary vein isolation. However, the association...
BACKGROUND
Complete right bundle branch block (CRBBB) is an important predictor of atrial fibrillation (AF) recurrence after pulmonary vein isolation. However, the association between CRBBB and AF development remains unclear.
METHODS
We performed a retrospective study of 2639 patients (male, n = 1549; female, n = 1090; mean age, 58 ± 13 years). CRBBB was defined as a late R (R') wave in lead V or V with a slurred S wave in lead I and/or lead V with a prolonged QRS duration (≥120 ms).
RESULTS
Among the 2639 patients, CRBBB was detected in 40 patients (1.5%), and the prevalence of AF was 7.4% (196/2639). The proportion of patients with AF and CRBBB was higher than the proportion of patients with AF without CRBBB (22.5% vs. 7.2%; p = 0.001). In the forward multivariate logistic analysis, CRBBB (odds ratio [OR], 3.329; 95% confidence interval [CI], 1.350-8.211; p = 0.009), complete left bundle branch block (OR, 2.209; 95% CI, 1.238-3.940; p = 0.007), age (OR, 1.020; 95% CI, 1.005-1.035; p = 0.009), valvular heart disease (OR, 2.332; 95% CI, 1.531-3.552; p < 0.001), left atrial diameter (OR, 1.133; 95% CI, 1.104-1.163; p < 0.001), left ventricular ejection fraction (OR, 1.023; 95% CI, 1.006-1.041; p = 0.007), and class I or III anti-arrhythmic drug use (OR, 10.534; 95% CI, 7.090-15.651; p < 0.001) were associated with AF.
CONCLUSION
Complete right bundle branch block was significantly associated with AF development in hospitalized patients with cardiovascular diseases.
Topics: Aged; Atrial Fibrillation; Bundle-Branch Block; Electrocardiography; Female; Humans; Male; Middle Aged; Retrospective Studies; Stroke Volume; Ventricular Function, Left
PubMed: 35567783
DOI: 10.1111/anec.12966 -
JACC. Clinical Electrophysiology Sep 2021This study sought to assess the predictive value of the proposed electrocardiogram and intracardiac electrogram characteristics for confirmation of left bundle branch...
OBJECTIVES
This study sought to assess the predictive value of the proposed electrocardiogram and intracardiac electrogram characteristics for confirmation of left bundle branch (LBB) capture.
BACKGROUND
Previously proposed criteria to distinguish left bundle branch pacing (LBBP) and left ventricular septum (LVS) pacing (LVSP) have not been fully validated.
METHODS
A His bundle pacing lead, an LBBP lead, and a multielectrode catheter at the LVS were placed. Direct LBB capture was defined as demonstration of retrograde His potential on the His bundle pacing lead and/or anterograde left conduction system potentials on the multielectrode catheter during LBBP. The routinely used parameters-His, LBB potential, time from stimulus to peak ventricular activation (Stim-LVAT), and paced QRS morphology during LVSP and LBBP at various depths and outputs were analyzed.
RESULTS
Thirty patients (21 non-left bundle branch block [LBBB], 9 LBBB) who demonstrated direct LBB capture using the defined criteria were included. The proportion of paced right bundle branch block was 100% during LBB capture in all patients compared to 23.4% in non-LBBB and 44.4% in LBBB during LVSP. LBB potential was recorded in all patients during intrinsic rhythm (non-LBBB group) or His corrective pacing in LBBB. Paced QRS duration was longer during selective LBBP compared to nonselective LBBP or LVSP only. All patients with characteristics of selective LBBP or abrupt decrease in Stim-LVAT of ≥10 ms demonstrated LBB capture.
CONCLUSIONS
Direct LBB capture can be confirmed by recording retrograde His potential and anterograde left conduction system potentials. Abrupt decrease in Stim-LVAT of ≥10 ms and demonstration of selective LBBP could be used as simple criteria to confirm LBB capture.
Topics: Bundle of His; Bundle-Branch Block; Cardiac Pacing, Artificial; Heart Rate; Humans; Ventricular Septum
PubMed: 33933414
DOI: 10.1016/j.jacep.2021.02.018 -
Clinical Cardiology Mar 2007Given its broad use as a screening tool, the electrocardiogram (ECG) has largely become one of the most common diagnostic tests performed in routine clinical practice.... (Review)
Review
Given its broad use as a screening tool, the electrocardiogram (ECG) has largely become one of the most common diagnostic tests performed in routine clinical practice. As a result, the finding of left bundle-branch block (LBBB) in the absence of a well-defined clinical setting has become relatively frequent and raises questions and often concerns. While in the absence of clinically detectable heart disease LBBB does not necessarily imply poor outcomes, physicians should be aware of the role of LBBB in stratifying risk of cardiovascular events and death in subjects with both ischemic and nonischemic heart disease. This paper reviews historical landmarks, pathophysiologic features, prognostic implications, and clinical management of LBBB in apparently healthy subjects and those with heart disease.
Topics: Bundle-Branch Block; Clinical Trials as Topic; Electrocardiography; Humans; Prevalence; Prognosis; Risk Factors
PubMed: 17385703
DOI: 10.1002/clc.20034 -
Current Cardiology Reviews 2021Many advances in the knowledge of medical science are due to the observation of an unknown phenomenon that remains an open question. A plausible hypothesis must be... (Review)
Review
Many advances in the knowledge of medical science are due to the observation of an unknown phenomenon that remains an open question. A plausible hypothesis must be demonstrated and proved through a scientific method in order to be accepted by the scientific community and the same results must be reached by following either the same or different techniques. The original case described by Rosenbaum MB et al., in this review triggered a series of anatomic and physiologic investigations with clinical and experimental observations that supported the trifascicular nature of the intraventricular conduction system of the heart and the concept of hemiblocks. The recognition and description of the left fascicular blocks made by the Argentinian School of Electrocardiology bridged an important gap in electrocardiography and many electrocardiograms that could not be explained until that moment could finally be understood. This review intends to redefine reliable criteria for the electrocardiographic and vectorcardiographic diagnosis of left fascicular blocks [hemiblocks]. The anatomy of the left bundle branch is also discussed to better understand the incidence, prevalence, clinical significance and main causes of left anterior and left posterior hemiblock either isolated or associated with right bundle branch block. This review offers the reader a reappraisal of the trifascicular nature of the intraventricular conduction system regarding the anatomy of the left bundle branch system and its pathophysiological and clinical significance.
Topics: Bundle-Branch Block; Electrocardiography; Heart Conduction System; Humans
PubMed: 32640960
DOI: 10.2174/1573403X16666200708111928 -
Trends in Cardiovascular Medicine Aug 2019The impact of left bundle branch block (LBBB) on cardiac mechanical function ranges from minimal effect in some patients to marked reduction in left ventricular (LV)... (Review)
Review
The impact of left bundle branch block (LBBB) on cardiac mechanical function ranges from minimal effect in some patients to marked reduction in left ventricular (LV) systolic function in others. It appears that this variability in part reflects differences in anatomical location of the bundle block. In most patients with LBBB and congestive heart failure, however, there is associated cardiac disease such as cardiomyopathies or coronary artery disease which contributes to LV dysfunction. The mechanism of harmful effect of LBBB on cardiac function is in-coordinated ventricular contractions which result in LV contractile inefficiency. Septal contribution to LV systolic function is lost or attenuated and an excessive workload is placed on the LV free wall which responds with remodeling and in some cases it decompensates. The magnitude of the contractile inefficiency depends on the extent of electrical conduction delay and degree of associated heart disease. Another mechanism, which in many patients contributes to cardiac dysfunction in LBBB, is mitral regurgitation due to in-coordinated contractions of the papillary muscles and altered mitral valve function due to LV remodeling. Potentially, reduced LV filling time due to prolonged LV systole may contribute to cardiac dysfunction, but there is limited knowledge about the clinical importance of this mechanism. In LBBB there is typically reduced septal perfusion, probably not as a sign of ischemia, but reflecting physiologic autoregulation of coronary flow in response to reduced septal work that reduces metabolic demand. Future studies should explore how current insights into mechanisms of cardiac mechanical effects of LBBB can be incorporated into decision algorithms for selection of patients for cardiac resynchronization therapy, as well as how to manage patients with LBBB and preserved LV function.
Topics: Action Potentials; Aged; Aged, 80 and over; Animals; Bundle of His; Bundle-Branch Block; Cardiac Resynchronization Therapy; Clinical Decision-Making; Disease Progression; Female; Heart Failure; Heart Rate; Humans; Male; Middle Aged; Mitral Valve; Mitral Valve Insufficiency; Patient Selection; Prognosis; Risk Assessment; Risk Factors; Ventricular Dysfunction, Left; Ventricular Function, Left; Ventricular Remodeling
PubMed: 30401603
DOI: 10.1016/j.tcm.2018.10.012