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Evolving Considerations in the Management of Patients With Left Bundle Branch Block and Suspected Myocardial Infarction

https://doi.org/10.1016/j.jacc.2012.02.054Get rights and content
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Patients with a suspected acute coronary syndrome and left bundle branch block (LBBB) present a unique diagnostic and therapeutic challenge to the clinician. Although current guidelines recommend that patients with new or presumed new LBBB undergo early reperfusion therapy, data suggest that only a minority of patients with LBBB are ultimately diagnosed with acute myocardial infarction, regardless of LBBB chronicity, and that a significant proportion of patients will not have an occluded culprit artery at cardiac catheterization. The current treatment approach exposes a significant proportion of patients to the risks of fibrinolytic therapy without the likelihood of significant benefit and leads to increased rates of false-positive cardiac catheterization laboratory activation, unnecessary risks, and costs. Therefore, alternative strategies to those for patients with ST-segment elevation myocardial infarction are needed to guide selection of appropriate patients with a suspected acute coronary syndrome and LBBB for urgent reperfusion therapy. In this article, we describe the evolving epidemiology of LBBB in acute coronary syndromes and discuss controversies related to current clinical practice. We propose a more judicious diagnostic approach among clinically stable patients with LBBB who do not have electrocardiographic findings highly specific for ST-segment elevation myocardial infarction.

Key Words

acute myocardial infarction
fibrinolysis
left bundle branch block

Abbreviations and Acronyms

ACS
acute coronary syndrome(s)
AMI
acute myocardial infarction
BBB
bundle branch block
CI
confidence interval
ECG
electrocardiography
LBBB
left bundle branch block
NSTEMI
non–ST-segment elevation myocardial infarction
PCI
percutaneous coronary intervention
STEMI
ST-segment elevation myocardial infarction

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This work was supported by Grant T32HL007360 from the National Heart, Lung, and Blood Institute to Dr. Neeland. Dr. Kontos has received lecture honoraria and consulting income from Sanofi-Aventis, Astellas, and AstraZeneca. Dr. de Lemos has received grant support from Roche Diagnostics and Abbott Diagnostics; lecture honoraria from BMS/Sanofi-Aventis; and consulting income from AstraZeneca.