Anterior ST elevation in a patient with RBBB.

Area of Science:

• Cardiology
• Electrocardiography
• Emergency Medicine

Background:

• Coronary artery disease (CAD) poses a significant risk for acute coronary syndromes (ACS).
• Right Bundle Branch Block (RBBB) on electrocardiogram (ECG) can complicate the diagnosis of ACS.
• Anterior ST-segment elevation and T-wave positivity in the context of RBBB may mimic ischemia.

Observation:

• A 79-year-old male with known CAD presented with chest pain.
• The presenting ECG revealed RBBB with mild anterior ST elevation and positive T waves.
• This ECG pattern was compared to a similar tracing from five years prior.

Findings:

• Despite ECG findings potentially suggestive of left anterior descending (LAD) coronary artery occlusion, the patient did not have ACS.
• The presenting ECG was notably similar to a baseline ECG from five years earlier.
• The absence of dynamic ECG changes and clinical signs of ACS was crucial.

Implications:

• ECG interpretation in patients with RBBB requires careful consideration of baseline tracings and clinical context.
• RBBB can mask or mimic ischemic changes, necessitating a comprehensive diagnostic approach.
• Prior ECGs are invaluable for evaluating acute changes in patients with pre-existing conduction abnormalities like RBBB.