Abstract Background The diagnostic utility of new or presumed new left bundle branch block (LBBB) for acute myocardial infarction (AMI) in the setting of acute coronary syndrome (ACS) remains controversial. Objective To evaluate whether the timing of LBBB predicts AMI and to compare its diagnostic accuracy with ischemic electrocardiography (ECG) criteria, particularly the Modified Sgarbossa Criteria (MSC). Methods We searched PubMed and Scopus for studies involving patients with ACS with LBBB through December 2023. Sensitivity, specificity, positive (LR+) and negative […]