Paradoxic abbreviation of repolarization in epicardium of the right ventricular outflow tract during augmentation of Brugada-type ST segment elevation.

We report the case of a 53-year-old Japanese man with a typical Brugada-like ECG in whom epicardial and endocardial activation-recovery intervals (ARI) in the right ventricular outflow tract (RVOT) were simultaneously measured by recording unipolar electrograms from the Pathfinder catheter introduced in the great cardiac vein as well as from the multielectrode basket catheter deployed in the RVOT. Epicardial ARI in the RVOT was abbreviated paradoxically at the beat of augmented ST segment elevation in lead V2 after a long pause or after pilsicainide injection. Endocardial ARI in the RVOT and epicardial ARI in the left ventricle were prolonged or were not changed. Our data support the hypothesis that heterogenous response of repolarization across the ventricular wall in the RVOT is responsible for accentuation of ST segment elevation in the right precordial leads.