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ESC Heart Failure Dec 2021Although increasingly recognized as a distinct pathological entity, left bundle branch block-induced cardiomyopathy (LBBB-ICMP) is not included among the possible...
AIMS
Although increasingly recognized as a distinct pathological entity, left bundle branch block-induced cardiomyopathy (LBBB-ICMP) is not included among the possible aetiologies of acquired dilated cardiomyopathies (DCM). While diagnostic criteria have been proposed, its recognition remains principally retrospective, in the presence of clinical and instrumental red flags. We aimed to assess the prevalence and clinical and instrumental features of LBBB-ICMP in a large cohort of patients with DCM.
METHODS AND RESULTS
We analysed a cohort of 242 DCM patients from a two-centre registry. Inclusion criteria were age > 18, non-ischaemic or non-valvular DCM, and LBBB on electrocardiogram. LBBB-ICMP was defined according to previously proposed diagnostic criteria: (i) neither family history nor clinically identifiable potential causes for DCM; (ii) negative genetic testing; (iii) echocardiographic features including non-severe chamber dilation, normal absolute and relative wall thickness, marked dyssynchrony, and normal right ventricular function; and (iv) absence of late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR). From the entire cohort, we identified 30 subjects (similar in terms of New York Heart Association class I or II in 80% vs. 75%, P = 0.56; QRS width of 150 ± 22 vs. 151 ± 24 ms, P = 0.82; and cardiac remodelling of baseline end-diastolic diameter 66 ± 8 vs. 65 ± 10 mm, P = 0.53) with a comprehensive dataset including CMR and genetic testing, required to verify the presence of the diagnostic criteria proposed for LBBB-ICMP. The main characteristics of this subgroup were 73% males, age 45 ± 13 years, left ventricular ejection fraction (LVEF) 30 ± 10%, LGE in 38% of patients, and QRS complex of 150 ± 22 ms. Patients were under guideline-directed medical therapy, and 57% of them were treated with cardiac resynchronization therapy (CRT). Two patients (6.67%, 50% males, age 53 ± 13 years) fulfilled the diagnostic criteria proposed for LBBB-ICMP. After a follow-up of 44 (12-76) months, LVEF was normal and QRS width significantly reduced (from 154 ± 25 to 116 ± 52 ms) in patients with LBBB-ICMP. Both patients were under optimal medical treatment, and one was implanted with CRT-D. Neither of the two patients experienced death, malignant ventricular arrhythmia, or heart failure hospitalization at follow-up.
CONCLUSIONS
Left bundle branch block-induced cardiomyopathy emerges as a distinct pathological entity, promptly identifiable in a minority but not negligible proportion of patients with newly diagnosed DCM and LBBB, using a series of diagnostic criteria including CMR and genetic testing. Further studies are needed to better elucidate the clinical course of LBBB-ICMP.
Topics: Adult; Aged; Bundle-Branch Block; Cardiomyopathies; Contrast Media; Female; Gadolinium; Humans; Male; Middle Aged; Prevalence; Registries; Retrospective Studies; Stroke Volume; Ventricular Function, Left
PubMed: 34510787
DOI: 10.1002/ehf2.13568 -
British Medical Journal Feb 1979
Topics: Bundle of His; Bundle-Branch Block; Electrocardiography; Humans; Prognosis
PubMed: 427397
DOI: No ID Found -
Annals of Noninvasive Electrocardiology... Jan 2022Right bundle-branch block (RBBB) and left bundle-branch block (LBBB) play a role in the pathogenesis and progression of coronary artery disease (CAD). However, the...
BACKGROUND
Right bundle-branch block (RBBB) and left bundle-branch block (LBBB) play a role in the pathogenesis and progression of coronary artery disease (CAD). However, the clinical features and the severity of coronary artery disease associated with different subtypes of bundle-branch block, according to time of new appearance, is not well characterized in patients with no known CAD.
METHODS
We retrospectively analyzed data pertaining to consecutive patients with RBBB or LBBB who underwent coronary angiography. The severity of coronary lesions was evaluated using the SYNTAX score. The differential effect of new-onset RBBB, old RBBB, new-onset LBBB, and old LBBB on the severity of CAD and its association with clinical characteristics was quantified. Multivariate logistic regression analysis was performed to evaluate the effect of RBBB and LBBB on the degree of coronary atherosclerosis in patients without known CAD.
RESULTS
Out of the 243 patients, 72 patients had old LBBB, 37 had new-onset LBBB, 93 patients had old RBBB, and 41 patients had new-onset RBBB. On univariate analysis, age, systolic blood pressure, diastolic blood pressure, creatinine, serum glucose, and glycosylated hemoglobin level were associated with high SYNTAX score (p < .05 for all). Patients in the new-onset RBBB, old RBBB, new-onset LBBB, and old LBBB groups showed significant differences in baseline characteristics and coronary atherosclerosis (p < .05 for all). However, there were no significant between-group differences with respect to the degree of coronary atherosclerosis as assessed by SYNTAX score.
CONCLUSIONS
New-onset RBBB, old RBBB, new-onset LBBB, and old LBBB were not associated with the severity of coronary lesions as assessed by SYNTAX score in patients without known CAD.
Topics: Arrhythmias, Cardiac; Bundle-Branch Block; Coronary Artery Disease; Electrocardiography; Humans; Retrospective Studies
PubMed: 34258804
DOI: 10.1111/anec.12883 -
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 -
BMC Cardiovascular Disorders Aug 2022To evaluate ventricular synchronization and function in patients with right bundle-branch block after left bundle-branch-area pacing (LBBAP) by echocardiography.
AIM
To evaluate ventricular synchronization and function in patients with right bundle-branch block after left bundle-branch-area pacing (LBBAP) by echocardiography.
METHODS
Forty patients who successfully received LBBAP were selected and divided into the right bundle-branch block group (RBBB group) and the non-RBBB group by pre-operation ECG. Echocardiography and follow-up were performed 1 month after operation. Interventricular synchronization was evaluated by tissue Doppler (TDI), tissue mitral annular displacement (TMAD), and interventricular mechanical delay. The tricuspid annular plane systolic excursion (TAPSE), right ventricular fractional area change (RVFAC), tricuspid annulus sidewall systolic velocity (TV-s'), left ventricular global ventricular longitudinal strain (GLS), right ventricular free wall longitudinal strain (LS-RV), standard deviation of left ventricular 18 segments peak time difference (SDt-L) and standard deviation of right ventricular free wall 3 segments peak time difference (SDt-R) were applied to evaluate intraventricular synchronization and ventricular function.
RESULTS
The difference of displacement peak time of the tricuspid and mitral valves, namely ΔPT measured by TMAD, the difference of systolic time to peak of the tricuspid and mitral valves, namely ΔTs measured by TDI, were statistically different between the two groups (P < 0.05). Compared with the non-RBBB group, there were no statistically significant differences in the GLS, RVFAC, LS-RV, TAPSE, TV-s', SDt-L, SDt-R (P > 0.05).
CONCLUSION
Echocardiography technology including two-dimensional speckle tracking imaging (2D-STI), TDI, and TMAD can effectively analyze interventricular synchronization, intraventricular synchronization, and ventricular function. Although the movement of the right ventricular myocardium in the RBBB group was slightly later than that of the left ventricular myocardium after LBBAP, LBBAP could still be applied in RBBB patients with pacing indication.
Topics: Bundle-Branch Block; Echocardiography; Heart Conduction System; Heart Ventricles; Humans; Ventricular Function, Left; Ventricular Function, Right
PubMed: 35989329
DOI: 10.1186/s12872-022-02818-z -
Reviews in Cardiovascular Medicine Mar 2022Transcatheter aortic valve replacement possesses a high validity for patients with aortic stenosis who are considered high risk for aortic valve replacement surgery,... (Review)
Review
Transcatheter aortic valve replacement possesses a high validity for patients with aortic stenosis who are considered high risk for aortic valve replacement surgery, nowadays it is also considered for patients with intermediate risk or even lower risk in certain situations. The incidence of new conduction abnormalities remains to be a tough problem, in particular, left bundle branch block. New-onset left bundle branch block is a major concern despite improvements in valve technology, and it may affect postoperative prognosis. Understanding the anatomical relationship between the conduction system and the aortic root, clarify factors related to the procedure, devices, and patients, might help to reduce the conduction abnormalities. Physiological pacing has emerged as a reasonable pacing strategy for patients with cardiac insufficiency post-valve replacement, especially combined with left bundle branch block. The purpose of this review is to summarize the current opinion on the incidence of new-onset left bundle branch block associated with transcatheter aortic valve replacement, to offer insights into its anatomical and procedural causes, clinical consequences, and more importantly, the prospect of applying physiological pacing as a therapeutic method for these patients.
Topics: Aortic Valve; Aortic Valve Stenosis; Arrhythmias, Cardiac; Bundle-Branch Block; Electrocardiography; Humans; Risk Factors; Transcatheter Aortic Valve Replacement; Treatment Outcome
PubMed: 35345257
DOI: 10.31083/j.rcm2303090 -
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 -
Annals of Noninvasive Electrocardiology... Jul 2020Complete left bundle branch block (cLBBB) is associated with increased cardiovascular mortality and heart failure. On the contrary, the clinical relevance of incomplete...
BACKGROUND
Complete left bundle branch block (cLBBB) is associated with increased cardiovascular mortality and heart failure. On the contrary, the clinical relevance of incomplete left bundle branch block (iLBBB) is less known. This study investigated the profile and outcome of iLBBB patients and assessed the risk of progression to cLBBB.
METHODS
Patients diagnosed with iLBBB between July 2013 and April 2018 were retrospectively included. Subsequently, echo- and electrocardiographic examinations at time of iLBBB diagnosis and during follow-up, as well as progression to non-strict cLBBB and strict cLBBB, were evaluated.
RESULTS
The study enrolled 321 patients (33% female, age 74 ± 11 years). During the follow-up of 21 (8;34) months, 33% of iLBBB patients evolved to non-strict cLBBB and 27% to strict cLBBB. iLBBB patients who evolved to non-strict or strict cLBBB were older, had more frequently reduced left ventricular ejection fraction, and had more often QRS notching/slurring in the lateral leads and inferior leads, compared to patients without progression to cLBBB. In multivariate analysis, only QRS notching/slurring in the lateral leads was independently associated with progression to non-strict cLBBB (odds ratio 4.64, p < .001) and strict cLBBB (odds ratio 9.6, p < .001). iLBBB patients with QRS notching/slurring had a progression rate to non-strict cLBBB of 52% and 49% to strict cLBBB.
CONCLUSION
Among patients with iLBBB, up to one third of the patients progress to cLBBB within a period of 2 years. The presence of QRS notching/slurring in the lateral leads during iLBBB was the strongest predictor for progression toward cLBBB.
Topics: Aged; Belgium; Bundle-Branch Block; Disease Progression; Electrocardiography; Female; Follow-Up Studies; Heart Ventricles; Humans; Male; Risk Assessment
PubMed: 31823461
DOI: 10.1111/anec.12732 -
JACC. Clinical Electrophysiology Sep 2021The aim of the study was to report the efficacy of left bundle branch pacing (LBBP) in the management of left bundle branch block (LBBB)-induced cardiomyopathy (LIC).
OBJECTIVES
The aim of the study was to report the efficacy of left bundle branch pacing (LBBP) in the management of left bundle branch block (LBBB)-induced cardiomyopathy (LIC).
BACKGROUND
Chronic LBBB is known to cause mechanical dyssynchrony and cardiomyopathy. Hyperresponse to cardiac resynchronization therapy (CRT) with biventricular pacing (BVP) is a hallmark of LIC. LBBP has recently shown promise as an alternative to BVP.
METHODS
Patients undergoing CRT between 2018 and 2020 were retrospectively screened, and those who met the criteria for LIC were included in the study. Duration of LBBB, CRT type, and response were documented. Pacing parameters, and electrocardiographic and echocardiographic data were collected.
RESULTS
Possible LIC was identified in 17 of 159 patients undergoing CRT and LBBP was successfully performed in 13 patients. Duration of LBBB before left ventricular dysfunction was 4.2 ± 3.9 years. Temporary His bundle pacing corrected underlying LBBB in all patients. During LBBP, there was significant reduction in QRS duration (167.8 ± 11.6 ms to 110.4 ± 13.1 ms; p < 0.0001) and repolarization parameters of QTc, Tpeak-Tend, and Tpeak-Tend/QTc ratio. LBBP threshold and R waves at implant were 0.53 ± 0.21 V/0.5 ms and 11.7 ± 7.1 mV and remained stable. Cardiac magnetic resonance imaging showed no evidence of scar (n = 8). During follow-up, left ventricular ejection fraction improved from 30.4 ± 6.6% to 57.4 ± 4.7% (p < 0.0001) and New York Heart Association functional class improved from 3.1 ± 0.3 to 1.2 ± 0.4 (p < 0.0001) compared with baseline.
CONCLUSIONS
LBBP is a reasonable option for CRT in patients with LIC, as it provides low and stable capture threshold with complete correction of underlying electrical and mechanical abnormalities associated with LBBB.
Topics: Bundle of His; Bundle-Branch Block; Cardiomyopathies; Humans; Retrospective Studies; Stroke Volume; Treatment Outcome; Ventricular Function, Left
PubMed: 33812829
DOI: 10.1016/j.jacep.2021.02.004 -
Journal of Cardiovascular Translational... Apr 2012Cardiac resynchronization therapy (CRT) aims to treat selected heart failure patients suffering from conduction abnormalities with left bundle branch block (LBBB) as the... (Review)
Review
Cardiac resynchronization therapy (CRT) aims to treat selected heart failure patients suffering from conduction abnormalities with left bundle branch block (LBBB) as the culprit disease. LBBB remained largely underinvestigated until it became apparent that the amount of response to CRT was heterogeneous and that the therapy and underlying pathology were thus incompletely understood. In this review, current knowledge concerning activation in LBBB and during biventricular pacing will be explored and applied to current CRT practice, highlighting novel ways to better measure and treat the electrical substrate.
Topics: Bundle-Branch Block; Cardiac Resynchronization Therapy; Electrocardiography; Humans; Treatment Outcome; Ventricular Function, Left
PubMed: 22311563
DOI: 10.1007/s12265-012-9351-1