Typical ECG changes unmasked by ajmaline in a patient with Brugada syndrome and left bundle branch block.

Brugada syndrome is a channelopathy associated with right bundle branch block and ST segment elevation in the right precordial leads. These electrocardiographic signs may not be apparent most of the time but can be unmasked by certain antiarrhythmic agents. Until now, all of the reports on this syndrome have focused on patients with no significant intraventricular conduction delay at baseline electrograms. In this report, we describe a patient with Brugada syndrome with left bundle branch block at baseline ECG. After intravenous ajmaline, the patient developed right bundle branch block and ST segment elevations in the right precordial leads.