[Concealed Brugada syndrome that became apparent incidentally during atrial fibrillation therapy].

A 31-year-old male patient was admitted to the emergency department with acute atrial fibrillation. After diltiazem infusion, a single oral dose of 600 mg propafenone was given to the patient for medical cardioversion. Approximately four hours later, sinus rhythym was restored. Re-evaluation of the admission ECG revealed right bundle branch block and saddleback-type ST-segment elevation of about 2 mm in V1-2 leads. Following propafenone, this type 2 Brugada ECG pattern turned to the coved type 1 Brugada pattern with ST elevation of more than 2 mm. After disappearance of propafenone effect, the ECG pattern turned to the type 2 Brugada pattern. Considering that the patient also had a family history of sudden cardiac death, electrophysiological study was conducted. During ventricular tachycardia stimulation, no ventricular arrhythmia was observed, thus the patient was scheduled to a close follow-up program.