A 35-year-old man presents with syncope. Baseline ECG shows coved ST elevation ≥2 mm in leads V1-V2 with T wave inversion, without ischemia or structural heart disease. His brother died suddenly at age 28. Which drug challenge is used to unmask this diagnosis in patients with suspected but non-diagnostic baseline ECG?

• A IV adenosine
• B IV procainamide
• C IV isoproterenol
• D IV ajmaline or flecainide (sodium channel blocker challenge) ✓

Explanation

Brugada syndrome diagnosis can be unmasked with sodium channel blockers (ajmaline, flecainide, procainamide) in patients with suspected disease but non-diagnostic baseline ECG. These drugs block INa, exaggerating the epicardial action potential notch in RV outflow tract and producing the diagnostic type 1 coved ST elevation. Ajmaline is preferred in Europe; flecainide is used in India and the US.

Reference: 2013 HRS/EHRA/APHRS Expert Consensus on Inherited Arrhythmia Syndromes

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.