Signal Anlysis Of Epicardium Mapping Electrograms In Canine ACh-AF Models

Background-Atrial fibrillation (AF) is known to be complex in its initiation and maintenance and results in life threatening cardiac arrhythmia. The method of evaluating probability of re-fibrillation after ablation by sinus electrogram (EG) is lacking in current literature. In our study, we predict duration of induced AF by analyzing the sinus EG of AF models under the influence of acetylcholine concentrations.Methods&Results-Using acute canine AF models (n=4), surface of the anterior and posterior left atrium and right atrium, as well as the pulmonary veins were attached to a intra-cardiac electrograms recording system with128electrical leads to form an electrocardiological mapping system. Acetylcholine (ACh) was injected at varying ladder-type concentrations. With Captured CT images of one canine model, we reconstructed the3D digital model using GVF-Snake algorithm and3D recontruction technology based on ROI contours. A parametric display method was devoloped on the3D/2D models using the classic Shepard algorithm and a Delaunay triangulation algorithm. A burst pacing stimulus was transmitted to the stimulating electrodes placed on the right atrium. Induced AF duration and times were recorded. We use induced AF duration to represent the maintaining ability of fibrillation pertaining to specific ACh concentration. According to the conception of phase synchronization, we assume that the sinus EG is periodically controlled by the sinus node. The Shannon entropy (SE) of the phase difference matrix extracted from the sinus EG was calculated and the results showed very much alike between the SE-ACh curves and induced AF duration-ACh curves. Further more, we also studied the influence of cut-off frequency and electrodes’number to the SE results.Conclusion-An increasement in randomness of atrial activation process in sinus EG precedes the increasement in AF duration which can represent the ability of AF maintenance. With further studies, the probability of long-time re-fibrillation after ablation can be evaluated using sinus EG.