Available online 21 September 2022

We describe two patient cases with acute coronary syndrome (ACS) and broad QRS in the acute phase electrocardiogram (ECG). The patients' ECG findings resembled left bundle branch block (LBBB), but with atypical features. Broad QRS not fulfilling the criteria for LBBB or right bundle branch block (RBBB) is diagnosed as non-specific intraventricular conduction delay (NSIVCD). The case report deals with the challenges of predicting acute coronary occlusion in patients with NSIVCD in their acute phase ECG. In one of the cases, the ECG changed from typical LBBB to NSIVCD or atypical LBBB with the development of systolic dysfunction and clinical heart failure.

Non-specific intra-ventricular conduction delay

Bundle branch block

Broad QRS

Acute coronary syndrome

Myocardial infarction

© 2022 The Authors. Published by Elsevier Inc.