Impact of hypokalemia on Brugada syndrome: case report unveiling mechanisms beyond QT interval prolongation

Brugada syndrome (BrS) is associated with an increased risk of sudden death caused by ventricular arrhythmias. The characteristic electrocardiographic appearance of ST-segment elevation of more than 2 mm with coved-type morphology in more than 1 right precordial lead is seen. Hypokalemia is known to unmask the Brugada type-1 pattern, but its exact role and mechanisms in this context are not well understood.

We report a case of first-time diagnosis of BrS in a 51-year-old man with hypokalemia 2.8 mmol/L. Despite the normalization of potassium levels with potassium chloride (KCL), the Brugada type-1 pattern persisted on ECG. Interestingly, the corrected QT interval was shorter during hypokalemia (QTc 390 ms) compared to when potassium levels were normal (QTc 432 ms).

This case highlights that hypokalemia can unmask the Brugada type-1 electrocardiographic pattern, but does not alter it once unmasked. The observed shorter QT interval during hypokalemia challenges the assumption that QT prolongation is the sole mechanism by which hypokalemia influences Brugada syndrome. This underscores the need for further research into additional mechanisms by which hypokalemia might trigger ventricular arrhythmias in Brugada syndrome.