Cavotricuspid Isthmus Anatomy in Flutter Ablation of Right Anevrismal Atrium Using Non Contact Mapping

tients with stmchmlly normal hearts following noncontact mapping guided ablation of idiopathic left or right ventricular tachycardia. A signiiicant inverse correlation was found between activation times and ARIs during sinus (I= -0.68&0.23), paced (I= -0.82&0.12), and ventricular ectopic (I= -0.66&0.43) rhythms using the alternative NCM method. However, no significant relationship between activation times and ARIs was found for sinus (I= 0.04&0.23), paced (I= 0.51&0.03), and ventricular ectopic (I= 0.22&0.17) rhythms using the Wyatt method at the same sites. In addition, the Wyatt method appeared to underestimate ARIs at endocardial sites with positive T waves resulting in signiiicantly larger global dispersion of repolatiation than the alternative method in these normal hearts (98&28 ms vs. 42&13 ms, P <O.OOl). Conclusions: The Wyatt method underestimates endocardial ARIs in areas with positive T waves and may be inaccurate in demonstrat ing global dispersion of repolarization or activation-repolarization relationship in the normal endocardium. The alternative NCM method may be a better determinant of endocardial repolarization patterns.