Feasibility of visualizing higher regions of Shannon entropy in atrial fibrillation patients.

Catheter ablation is associated with limited success rates in patients with persistent atrial fibrillation (AF), which is mostly maintained by rotors that are located outside of pulmonary veins (PV) region. None of the currently available commercial mapping systems can accurately predict the rotor location outside of PV in patients with persistent AF. Experimental verification of the feasibility of using Shannon entropy (SE) based mapping technique based on symbolic dynamics approach to identify pivotal points of rotors in isolated rabbit hearts was performed. This mapping approach was applied to clinical intracardiac electrograms from a patient with persistent AF to construct a 3-dimensional (3D) SE map. Our results demonstrate that SE can correctly predict the pivot point of the rotor in animal model. We also demonstrated the feasibility of generating 3D SE maps using current catheter mapping methods to identify active rotor sites that may maintain AF. Higher SE areas are noted at the base of right atrial appendage. Further clinical studies are needed to validate ablation of areas with high SE with outcomes.