QRS&T wave alternans and beat-to-beat ventricular repolarization variability assessed from 12-lead holters in patients with suspected Brugada syndrome

Microvolt 2:1 T wave alternans (TWA) and increased beat-to-beat repolarization variability have been reported in Brugada syndrome (BS) and could be related to increased arrhythmic risk. We hypothesized that among patients (pts) with suspected BS, those with positive diagnostic ajmaline test (i.e. likely carriers of BS mutations) have greater TWA or beat-to-beat repolarization variability on 24-hour Holter recordings that those with negative tests. Six 5-minutes night-time ECGs in 14 pts with suspected BS and positive (n = 7, 4 male) and negative (n = 7, 3 male) ajmaline tests were analyzed for a) 2:1 alternans of the QRS and T using Principal Component Analysis (PCA) of QRS and T waves b) PCA variability measured as standard deviation of PCA of all QRS and T waves. Beat-to beat repolarization variability, but not 2:1 TWA is increased in pts with positive ajmaline tests. Regular QRS alternans is increased in pts with positive ajmaline tests.