Electrocardiographic Case: Diagnosis of Acute Myocardial Infarction in the Presence of Left Bundle Branch Block

LF Hsu, RML Kam, WS Teo
Correspondence: Dr WS Teo

ABSTRACT
The electrocardiographic features associated with acute myocardial infarction (AMI) are often easily recognised. However, interpretation is made more difficult in the presence of confounding patterns such as a left bundle branch block (LBBB). This may result in missed cases which may otherwise have benefited from acute revascularisation therapy. Though not straightforward, the diagnosis of AMI in the presence of LBBB can be made with a reasonable amount of accuracy. We report a case of acute myocardial infarction with LBBB that was appropriately diagnosed and underwent acute revascularisation by angioplasty. A detailed knowledge of the typical electrocardiographic features associated with LBBB, especially the ST segment morphologies, is very important. This will greatly aid recognition of an evolving AMI and help us decide on the most appropriate therapy.

Keywords: acute myocardial infarction, diagnosis, electrocardiogram, left bundle branch block
Singapore Med J 2000; 41(3): 139-141