A 41-year-old man developed sustained monomorphic ventricular tachycardia (VT) with a left bundle branch block and inferior axis pattern during treadmill exercise concomitantly with unmasking of the typical Brugada electrocardiography (ECG) pattern. The typical ECG phenotype was provoked by a class IC drug. VT was not inducible with programmed electrical stimulation, but premature ventricular beat and non-sustained VT with the same morphology increased in frequency with isoproterenol treatment. Additionally, atrioventricular nodal reentrant tachycardia (AVNRT) was induced by electrical stimulation and VT and AVNRT were treated by radiofrequency catheter ablation.