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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 -
Circulation. Arrhythmia and... Apr 2020Left bundle branch block may be due to conduction system degeneration or a reflection of myocardial pathology. Left bundle branch block may also develop following aortic... (Review)
Review
Left bundle branch block may be due to conduction system degeneration or a reflection of myocardial pathology. Left bundle branch block may also develop following aortic valve disease or cardiac procedures. Patients with heart failure with reduced ejection fraction and left bundle branch block may respond positively to cardiac resynchronization therapy. Lead placement via the coronary sinus is the mainstay approach of cardiac resynchronization therapy. However, other options, including physiological pacing, are being explored. In this review, we summarize the salient pathophysiologic and clinical aspects of left bundle branch block, as well as current and future strategies for management.
Topics: Action Potentials; Bundle of His; Bundle-Branch Block; Cardiac Resynchronization Therapy; Heart Rate; Humans; Recovery of Function; Risk Factors; Treatment Outcome
PubMed: 32186936
DOI: 10.1161/CIRCEP.119.008239 -
Cardiac Electrophysiology Clinics Dec 2021Left bundle branch block (LBBB) is not just a simple electrocardiogram alteration. The intricacies of this general terminology go beyond simple conduction block. This... (Review)
Review
Left bundle branch block (LBBB) is not just a simple electrocardiogram alteration. The intricacies of this general terminology go beyond simple conduction block. This review puts together current knowledge on the historical concept of LBBB, clinical significance, and recent insights into the pathophysiology of human LBBB. LBBB is an entity that affects patient diagnosis (primary conduction disease, secondary to underlying pathology or iatrogenic), treatment (cardiac resynchronization therapy or conduction system pacing for heart failure), and prognosis. Recruiting the left bundle branch with conduction system pacing depends on the complex interaction between anatomy, site of pathophysiology, and delivery tools.
Topics: Bundle-Branch Block; Cardiac Resynchronization Therapy; Electrocardiography; Heart Conduction System; Heart Failure; Humans
PubMed: 34689894
DOI: 10.1016/j.ccep.2021.07.005 -
Journal of Cardiovascular... Sep 2020Cardiac pacing is the only effective therapy for patients with symptomatic bradyarrhythmia. Traditional right ventricular apical pacing causes electrical and mechanical... (Review)
Review
Cardiac pacing is the only effective therapy for patients with symptomatic bradyarrhythmia. Traditional right ventricular apical pacing causes electrical and mechanical dyssynchrony resulting in left ventricular dysfunction, recurrent heart failure, and atrial arrhythmias. Physiological pacing activates the normal cardiac conduction, thereby providing synchronized contraction of ventricles. Though His bundle pacing (HBP) acts as an ideal physiological pacing modality, it is technically challenging and associated with troubleshooting issues during follow-up. Left bundle branch pacing (LBBP) has been suggested as an effective alternative to overcome the limitations of HBP as it provides low and stable pacing threshold, lead stability, and correction of distal conduction system disease. This paper will focus on the implantation technique, troubleshooting, clinical implications, and a review of published literature of LBBP.
Topics: Bundle of His; Bundle-Branch Block; Cardiac Pacing, Artificial; Electrocardiography; Heart Conduction System; Humans
PubMed: 32681681
DOI: 10.1111/jce.14681 -
Cardiac Electrophysiology Clinics Dec 2021Left bundle branch block (LBBB) and right bundle branch block (RBBB) are classic manifestations of bundle branch conduction disorders. However, a third form that is... (Review)
Review
Left bundle branch block (LBBB) and right bundle branch block (RBBB) are classic manifestations of bundle branch conduction disorders. However, a third form that is uncommon and underrecognized may exist that has features and pathophysiology of both: bilateral bundle branch block (BBBB). This unusual form of bundle branch block exhibits an RBBB pattern in lead V1 (terminal R wave) and an LBBB pattern in leads I and aVL (absence of S wave). This unique conduction disorder may confer an increased risk of adverse cardiovascular events. BBBB patients may be a subset of patients that respond well to cardiac resynchronization therapy.
Topics: Bundle-Branch Block; Cardiac Conduction System Disease; Cardiac Resynchronization Therapy; Electrocardiography; Heart Conduction System; Humans
PubMed: 34689895
DOI: 10.1016/j.ccep.2021.06.008 -
Heart Rhythm Aug 2022Cardiac resynchronization therapy (CRT) with biventricular pacing (BVP) is well-established therapy in patients with reduced left ventricular ejection fraction (LVEF)... (Observational Study)
Observational Study
BACKGROUND
Cardiac resynchronization therapy (CRT) with biventricular pacing (BVP) is well-established therapy in patients with reduced left ventricular ejection fraction (LVEF) and bundle branch block or indication for pacing. Conduction system pacing (CSP) using His-bundle pacing (HBP) or left bundle branch area pacing (LBBAP) has been shown to be a safe and more physiological alternative to BVP.
OBJECTIVE
The purpose of this study was to compare the clinical outcomes between CSP and BVP among patients undergoing CRT.
METHODS
This observational study included consecutive patients with LVEF ≤35% and class I or II indications for CRT who underwent successful BVP or CSP at 2 major health care systems. The primary outcome was the composite endpoint of time to death or heart failure hospitalization (HFH). Secondary outcomes included subgroup analysis in left bundle branch block as well as individual endpoints of death and HFH.
RESULTS
A total of 477 patients (32% female) met inclusion criteria (BVP 219; CSP 258 [HBP 87, LBBAP 171]). Mean age was 72 ± 12 years, and mean LVEF was 26% ± 6%. Comorbidities included hypertension 70%, diabetes mellitus 45%, and coronary artery disease 52%. Paced QRS duration in CSP was significantly narrower than BVP (133 ± 21 ms vs 153 ± 24 ms; P <.001). LVEF improved in both groups during mean follow-up of 27 ± 12 months and was greater after CSP compared to BVP (39.7% ± 13% vs 33.1% ± 12%; P <.001). Primary outcome of death or HFH was significantly lower with CSP vs BVP (28.3% vs 38.4%; hazard ratio 1.52; 95% confidence interval 1.082-2.087; P = .013).
CONCLUSION
CSP improved clinical outcomes compared to BVP in this large cohort of patients with indications for CRT.
Topics: Aged; Aged, 80 and over; Bundle of His; Bundle-Branch Block; Cardiac Resynchronization Therapy; Electrocardiography; Female; Heart Failure; Humans; Male; Middle Aged; Stroke Volume; Treatment Outcome; Ventricular Function, Left
PubMed: 35500791
DOI: 10.1016/j.hrthm.2022.04.023 -
Cardiology Clinics Aug 2023Left bundle branch block (LBBB) and right bundle branch block (RBBB) are classic manifestations of bundle branch conduction disorders. However, a third form that is... (Review)
Review
Left bundle branch block (LBBB) and right bundle branch block (RBBB) are classic manifestations of bundle branch conduction disorders. However, a third form that is uncommon and underrecognized may exist that has features and pathophysiology of both: bilateral bundle branch block (BBBB). This unusual form of bundle branch block exhibits an RBBB pattern in lead V1 (terminal R wave) and an LBBB pattern in leads I and aVL (absence of S wave). This unique conduction disorder may confer an increased risk of adverse cardiovascular events. BBBB patients may be a subset of patients that respond well to cardiac resynchronization therapy.
Topics: Humans; Bundle-Branch Block; Electrocardiography; Cardiac Conduction System Disease; Heart Conduction System; Cardiac Resynchronization Therapy
PubMed: 37321689
DOI: 10.1016/j.ccl.2023.03.011 -
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 -
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 -
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