Abstract 13006: Electrophysiologic Characteristics of the Focal Discharges Critical for the Initiation of Atrial Fibrillation and its Relation to the Complex Fractionated Electrogram Region: Three-dimensional Analysis Using Non-contact Mapping
Background: It has not been well clarified how the atrial fibrillation (AF) was initiated by the focal discharge. Also, it is not clear what characteristics of focal discharge are prerequisite for the initiation of AF.
Objectives: The purpose of this study was to define the electrophysiologic characteristics of focal discharges which initiate the random wave propagation at AF onset and clarify the mechanism of AF initiation, especially in relation to the complex fractionated atrial electrograms (CFAE) region.
Methods: Nineteen patients with paroxysmal AF (17 men, mean age 57 years) in whom the spontaneous AF onset was observed during non-contact mapping (EnSite 3000) of the left atrium were included. To define the electrophysiologic characteristics of focal discharge critical for the initiation of random wave propagation, we analyzed the left atrial activation following focal discharges at AF onset. The coupling interval, left atrial activation time and atrial activation sequence were compared between focal discharges which initiated random wave propagation (AF-D) and those did not (non-AF-D).
Results: There were 32 spontaneous AF onset episodes. All of these AF were initiated by the focal repetitive discharges (8.6±8.6 beats), derived from pulmonary vein (PV) (n=17) and from non-PV CFAE region (n=15). The mean coupling interval of AF-D was significantly shorter than that of non-AF-D (179.3±33.2 vs. 216.6±44.8 msec, p=0.0005). The left atrial activation time of AF-D was significantly longer than that of non-AF-D (151.3±35.1 vs. 82.6±16.5 msec, p<0.0001). Prolonged left atrial activation time following AF-D was caused by the heterogeneous activation over the left atrium associated with localized conduction block in the CFAE region. This prolonged left atrial activation time following AF-D enabled the wave to reenter the CFAE region through the previously localized block region from the opposite direction and random reentrant wave propagation was initiated subsequently.
Conclusions: A critically short coupling interval of focal discharge and subsequent prolonged left atrial activation time, associated with localized conduction block in the CFAE region, were the crucial factors for the initiation of random wave propagation at the onset of AF.
- © 2010 by American Heart Association, Inc.