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Left Bundle Branch Block, an Old–New Entity
Left bundle branch block (LBBB) is generally associated with a poorer prognosis in comparison to normal intraventricular conduction, but also in comparison to right bundle branch block which is generally considered to be benign in the absence of an underlying cardiac disorder like congenital heart d...
Autores principales: | , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Springer US
2012
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3294212/ https://www.ncbi.nlm.nih.gov/pubmed/22258866 http://dx.doi.org/10.1007/s12265-011-9344-5 |
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author | Breithardt, Günter Breithardt, Ole-Alexander |
author_facet | Breithardt, Günter Breithardt, Ole-Alexander |
author_sort | Breithardt, Günter |
collection | PubMed |
description | Left bundle branch block (LBBB) is generally associated with a poorer prognosis in comparison to normal intraventricular conduction, but also in comparison to right bundle branch block which is generally considered to be benign in the absence of an underlying cardiac disorder like congenital heart disease. LBBB may be the first manifestation of a more diffuse myocardial disease. The typical surface ECG feature of LBBB is a prolongation of QRS above 0.11 s in combination with a delay of the intrinsic deflection in leads V5 and V6 of more than 60 ms and no septal q waves in leads I, V5, and V6 due to the abnormal septal activation from right to left. LBBB may induce abnormalities in left ventricular performance due to abnormal asynchronous contraction patterns which can be compensated by biventricular pacing (resynchronization therapy). Asynchronous electrical activation of the ventricles causes regional differences in workload which may lead to asymmetric hypertrophy and left ventricular dilatation, especially due to increased wall mass in late-activated regions, which may aggravate preexisting left ventricular pumping performance or even induce it. Of special interest are patients with LBBB and normal left ventricular dimensions and normal ejection fraction at rest but who may present with an abnormal increase in pulmonary artery pressure during exercise, production of lactate during high-rate pacing, signs of ischemia on myocardial scintigrams (but no coronary artery narrowing), and abnormal ultrastructural findings on myocardial biopsy. For this entity, the term latent cardiomyopathy had been suggested previously. |
format | Online Article Text |
id | pubmed-3294212 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2012 |
publisher | Springer US |
record_format | MEDLINE/PubMed |
spelling | pubmed-32942122012-03-21 Left Bundle Branch Block, an Old–New Entity Breithardt, Günter Breithardt, Ole-Alexander J Cardiovasc Transl Res Article Left bundle branch block (LBBB) is generally associated with a poorer prognosis in comparison to normal intraventricular conduction, but also in comparison to right bundle branch block which is generally considered to be benign in the absence of an underlying cardiac disorder like congenital heart disease. LBBB may be the first manifestation of a more diffuse myocardial disease. The typical surface ECG feature of LBBB is a prolongation of QRS above 0.11 s in combination with a delay of the intrinsic deflection in leads V5 and V6 of more than 60 ms and no septal q waves in leads I, V5, and V6 due to the abnormal septal activation from right to left. LBBB may induce abnormalities in left ventricular performance due to abnormal asynchronous contraction patterns which can be compensated by biventricular pacing (resynchronization therapy). Asynchronous electrical activation of the ventricles causes regional differences in workload which may lead to asymmetric hypertrophy and left ventricular dilatation, especially due to increased wall mass in late-activated regions, which may aggravate preexisting left ventricular pumping performance or even induce it. Of special interest are patients with LBBB and normal left ventricular dimensions and normal ejection fraction at rest but who may present with an abnormal increase in pulmonary artery pressure during exercise, production of lactate during high-rate pacing, signs of ischemia on myocardial scintigrams (but no coronary artery narrowing), and abnormal ultrastructural findings on myocardial biopsy. For this entity, the term latent cardiomyopathy had been suggested previously. Springer US 2012-01-19 2012 /pmc/articles/PMC3294212/ /pubmed/22258866 http://dx.doi.org/10.1007/s12265-011-9344-5 Text en © The Author(s) 2012 https://creativecommons.org/licenses/by-nc/4.0/ This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. |
spellingShingle | Article Breithardt, Günter Breithardt, Ole-Alexander Left Bundle Branch Block, an Old–New Entity |
title | Left Bundle Branch Block, an Old–New Entity |
title_full | Left Bundle Branch Block, an Old–New Entity |
title_fullStr | Left Bundle Branch Block, an Old–New Entity |
title_full_unstemmed | Left Bundle Branch Block, an Old–New Entity |
title_short | Left Bundle Branch Block, an Old–New Entity |
title_sort | left bundle branch block, an old–new entity |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3294212/ https://www.ncbi.nlm.nih.gov/pubmed/22258866 http://dx.doi.org/10.1007/s12265-011-9344-5 |
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