The Effects of Flecainide on QT Interval and Dispersion in Brugada Syndrome: Insights from a Retrospective Analysis

Background: Brugada syndrome (BrS) is a genetic cardiac disorder characterized by specific electrocardiogram (ECG) abnormalities and a heightened risk of sudden cardiac death. The role of antiarrhythmic drugs, particularly flecainide, in modifying ECG parameters in BrS patients’ remains underexplored. Objectives: This study aims to evaluate the effects of flecainide on the QT interval and QT dispersion in patients diagnosed with or suspected of having BrS. Methods: A retrospective analysis was conducted involving 20 patients, divided into two groups: Ten diagnosed with BrS and 10 without. Each participant received a 300 mg oral dose of flecainide, followed by continuous ECG monitoring for 24 hours. Key ECG parameters, including the QT interval, QTc interval, and QT dispersion, were analyzed pre-and-post-administration. Results: Post-flecainide administration, a significant increase in the right QT interval was observed in the overall cohort (P = 0.04). Notably, while BrS patients exhibited changes, none were statistically significant. In contrast, non-BrS patients showed significant increases in left QTD, right QT, and right QTc intervals (P = 0.02, P = 0.03, P = 0.02, respectively). Conclusions: Flecainide significantly alters ECG parameters, particularly in non-Brugada patients, emphasizing its diagnostic utility in confirming BrS. These findings highlight the need for refined diagnostic strategies and tailored management approaches for patients at risk of arrhythmogenic events.