Abstract 13091: The Prefereble Anatomical Location of the Functional Conduction Block Line Preceded by the Onset of Random Meandering Reentrant Wave Propagation in Patients with Atrial Fibrillation: Analysis by the Non-Contact Mapping
Background: It has been shown that the random reentrant wave propagation is induced following the formation of the functional line of block in the left atrium (LA). However precise anatomical location of this block line and its length has not been clarified.
Objective: The purpose of this study was to elucidate the preferable location and the length of the functional block line which is formed at the onset of random reentry in AF.
Methods: Twenty-four patients with AF in whom the spontaneous AF onset was detected during the endocardial mapping (EnSite 3000) of LA were included. The prevalence of the functional conduction block and its lengths were examined in 8 divided areas of the LA (right pulmonary vein (PV), left PV, left atrial appendage and roof, anterior, posterior, septal and lateral LA).
Results: There were 37 spontaneous AF onset episodes induced by the focal discharge derived from PV (n=13) and non-PV (n=24). Random wave propagation was initiated following a formation of the functional conduction block. The mean length of the functional conduction block was 47.1 ± 24.2mm. The length of functional conduction block at right PV, left PV, left atrial appendage and roof, anterior, posterior, septal and lateral LA were 12.4±8.1, 16.0±2.8, 13.3±6.3, 39.5±19.8, 8.5±5.7, 14.0±0 and 23.0±0 mm. There were single functional conduction block line in 35 episodes and double conduction block lines in 2 episodes. The functional conduction block was observed in a single LA area in 14 episodes and encompassed >2 LA areas in the remaining 23 episodes, thus it distributed over 62 LA areas. The roof LA showed the highest prevalence of conduction block (38 of 62 LA areas, 61.3%, p<0.001) and the longest length of conduction block line (39.5 ± 19.8 mm, p<0.02) compared with the other areas. There was no difference in the prevalence and length of functional conduction block between AF onset episodes induced by PV and non-PV.
Conclusion: Meandering reentrant wave propagation was initiated following the functional conduction block which was frequently formed at the roof of the LA. The anatomical characteristics of the roof with thickened wall and overlapping of three or more myocardial layers may provide the substrate of functional conduction block.
- © 2012 by American Heart Association, Inc.