Repolarization Alternans and XXXX in a Repaired Tetralogy of Fallot Animal Model.

@entity1 @entity1165 @entity235 @entity338 @entity52742 @entity460 @entity943 @entity204
BACKGROUND: @entity943 is an important cause of late @entity204 in @entity1 with repaired tetralogy of Fallot (rTOF). By using an rTOF @entity235 model, we investigated the role of repolarization alternans and its electrophysiological mechanisms. METHODS AND RESULTS: Six @entity235 received right ventricular outflow tract (RVOT) transannular patch, @entity338 , and right bundle branch ablation to simulate rTOF. After 1 year, we performed high-resolution dual-voltage and @entity460 optical mapping to record action potentials and @entity460 transients on the excised right ventricular outflow tract wedges. Another 6 @entity235 without operation served as control. The rTOF group was more susceptible to action potential duration alternans (APD-ALT) and spatially discordant APD-ALT than control (threshold for APD-ALT: 516  36 vs 343  36 ms; P=0.017; threshold for discordant APD-ALT: 387  30 vs 310  14 ms; P=0.046). We detected 2 episodes of @entity1165 in the rTOF group, but none in the control. Expressions of Kv4.3 and @entity52742 decreased in the rTOF group. Expression of connexin 43 also decreased in the rTOF group with a corresponding decrease of conduction velocity and might contribute to spatially discordant APD-ALT. We also found distinct electrophysiological features of the RVOT, including biphasic relationship between magnitude of APD-ALT and pacing cycle length, uncoupling of APD-ALT, and @entity460 transients alternans, and shortened APD, but unchanged, APD restitution in rTOF. CONCLUSIONS: We demonstrated novel electrophysiological properties of the RVOT. In an rTOF model, the RVOT exhibits increased susceptibility to temporal and spatially discordant APD-ALT, which was not totally dependent on @entity460 transient alternans.
