Abstract 13980: Anatomical Configuration of the Inferior Vena Cava-Tricuspid Annulus Isthmus: Relevance to difficulty of Catheter Ablation of Typical Atrial Flutter
Background: Linear ablation between the inferior vena cava and tricuspid annulus isthmus (CTI) is a common strategy to treat typical atrial flutter. However, sometimes it is difficult to complete CTI ablation. We investigated whether the evaluation of the CTI morphology by preprocedure multidetecter computed tomography (MDCT) could rationalize the ablation approach.
Methods: We enrolled 160 patients [130 men and 30 women; mean age, 61 years ± 10 (standard deviation)] with typical atrial flutter successfully ablated using an 8-mm tip ablation catheter. The anatomical region of the CTI was evaluated by preprocedure contrast-enhanced MDCT examination. We measured the CTI length, thickness, and angle. We classified the CTI into 3 types according to the central isthmus depth: straight (3 mm), concave (3 to 5 mm), or pouch-like (>5 mm). All measurements were performed on the atrial end-diastole phase.
Results: The CTI mean length was 30 ± 8 mm, the mean wall thickness was 1.7 ± 0.4 mm, and the mean angle was 101 ± 24°. Straight type CTI was observed in 55% of the subjects, concave type in 25%, and pouch-like type in 20%. An Eustachian valve was observed in 18% of the subjects. The procedure required a significantly longer time in the presence of an Eustachian valve or a concave isthmus (p < 0.05) than in their absence. Moreover, the procedure required longer time in case of a steep angle (<80°) than in case of a wide angle (≥80°) (51 ± 29 minutes vs 14 ± 13 minutes, p < 0.0001). There was a significant negative correlation between the CTI angle and the procedure time (r = −0.661, p < 0.0001).
Conclusions: Cardiac MDCT reveals a highly variable isthmus anatomy, including particular configurations that can make ablation more laborious. Understanding isthmus anatomy by preprocedural MDCT and rational adaptation of the ablation strategy based on the anatomical findings may contribute to shorten time needed completing ablation.
- © 2010 by American Heart Association, Inc.