Ajmaline-induced Brugada Phenocopy, Right Bundle Branch Block, or Both?

Area of Science:

• Cardiology
• Clinical Electrophysiology
• Diagnostic Testing

Background:

• Brugada syndrome (BrS) is a potentially life-threatening inherited cardiac arrhythmia.
• Ajmaline, a sodium channel blocker, is a key provocative agent in diagnosing BrS.
• The ajmaline test aims to unmask the characteristic Type 1 Brugada electrocardiogram (ECG) pattern.

Observation:

• The administration of ajmaline can induce not only the diagnostic Type 1 Brugada pattern but also other ECG abnormalities.
• Right bundle branch block (RBBB) is a potential confounding finding during ajmaline testing.
• In this case, RBBB emerged during ajmaline administration, complicating the interpretation.

Findings:

• The induced RBBB masked the typical coved ST-segment elevation diagnostic of BrS.
• This ECG manifestation presented a significant challenge in confirming or excluding BrS.
• The case highlights the potential for RBBB to interfere with ajmaline test interpretation.

Implications:

• Accurate interpretation of ajmaline test results is crucial for BrS diagnosis.
• Clinicians must be aware of confounding ECG findings like RBBB during provocative testing.
• Further research may be needed to refine diagnostic strategies for BrS in the presence of RBBB.