Intravenous administration of class I antiarrhythmic drugs induced T wave alternans in a patient with Brugada syndrome

A 71-year-old man who experienced aborted sudden death was referred to our hospital, Coronary artery disease and cerebral accident were ruled out by conventional tests. The 12-lead ECG obtained at rest showed a right bundle branch block pattern and ST segment elevation in leads V-1 to V-3, Double ventricular extrastimuli at coupling intervals >180 msec induced ventricular fibrillation (VF) twice during electrophysiologic study. Intravenous administration of procainamide accentuated ST segment elevation in leads V-1 to V-3, and visible T wave alternans was induced in leads V-2 and V-3 at a dose of 450 mg, Initiation of T wave alternans was not associated with changes of the cardiac cycle or development of premature beats. When procainamide infusion was discontinued, T wave alternans disappeared before the elevated ST segment returned to the control level. Pilsicainide also accentuated ST segment elevation and induced similar T wave alternans in leads V-2 and V-3, Class I antiarrhythmic drug-related T wave alternans has been reported rarely in Brugada syndrome, but it may represent enhanced arrhythmogenicity of VF, We need to monitor closely and study the clinical implications of T wave alternans in Brugada syndrome.