Left bundle branch block, chest pain and catheterization laboratory activation: an unavoidable cascade reaction?

Abstract Identification of acute myocardial infarction (AMI) in the presence of left bundle branch block (LBBB) remains challenging. European guidelines recommend prompt reperfusion therapy in patients with suspected ongoing myocardial ischemia and new or presumably new LBBB, whereas AHA/ACC guidelines state that LBBB should not be considered diagnostic of AMI in isolation. Sgarbossa criteria and their recent modified version with the introduction of ST/S ratio can be helpful in this setting. A clinical–instrumental algorithm to manage suspected AMI in the presence of LBBB has been recently proposed. We present five paradigmatic clinical cases.