There are lots of questions raised recently regarding activation of cath. lab in the setting of new LBBB or presumed new LBBB. It is really challenging when you have a patient with chest pain and there is no old EKG to compare findings of LBBB.
The following articles review the utility of PCI in the setting of LBBB.The main conclusions are majority of patients who went to cath lab with these criteria did not have AMI, and they proposed for reconsideration of activation of cath lab in LBBB.
Jain etal, “Utility of left bundle branch block as a diagnostic criterion for acute myocardial infarction” 2011, American Journal of Cardiology