Quinidine in Brugada Syndrome — EECC MCQ

Correct answer: A — Quinidine (a class IA antiarrhythmic that blocks Ito current) is used for: (1) VF storm in Brugada; (2) recurrent ICD shocks; (3) patients who decline or cannot have ICD; (4) asymptomatic high-risk patients in regions where ICD access is limited

Quinidine is the only pharmacological therapy with consistent evidence for suppressing VF in Brugada syndrome. Mechanism: quinidine blocks the transient outward potassium current (Ito), which is the dominant current in the Brugada pathophysiology (Ito-mediated loss of the action potential dome in the RV epicardium creates the transmural voltage gradient). By blocking Ito, quinidine normalises the epicardial action potential and reduces arrhythmic risk. The 2022 ESC VA/SCD Guidelines recommend quinidine (Class IIa) for: electrical storm, frequent appropriate ICD shocks, patients who decline/cannot have ICD, and as adjunctive therapy to ICD. Limitations: GI side effects, QT prolongation risk, limited global availability (supply issues in many countries). Dose: 600-900 mg daily with QTc monitoring.

Reference: ESC (2022): VA/SCD Guidelines