Right Bundle Branch and Bifascicular Blocks: Insensitive Prognostic Indicators for Acute Myocardial Infarction.

Area of Science:

• Cardiology
• Emergency Medicine

Background:

• The clinical significance of right bundle branch block (RBBB) and bifascicular block (BFB) in acute myocardial infarction (AMI) remains uncertain.
• These ECG findings are relatively uncommon in patients presenting with chest pain.

Purpose of the Study:

• To evaluate the clinical utility of RBBB or BFB in diagnosing AMI.
• To determine if these blocks influence the incidence of acute coronary syndrome (ACS).

Main Methods:

• Retrospective analysis of patients presenting to the emergency department with chest pain.
• Identification of patients with RBBB or BFB and assessment for ACS.
• Comparison of ACS incidence between new/presumed new and prior known blocks.

Main Results:

• RBBB was identified in 2.8% of patients with chest pain; 8.5% of these had ACS.
• No significant difference in ACS incidence was observed between new/presumed new and prior known RBBB or BFB.
• ST-segment depression in V1-3 can mask anterior ST-elevation in some cases.

Conclusions:

• RBBB and BFB, in isolation, appear to have limited clinical utility in suspected AMI diagnosis, contrary to some guidelines.
• Patients with suspected AMI, RBBB, and ST-elevation in leads V1-3 should be prioritized for emergent coronary angiography.