The Hunt for Rotors and Focal Sources as a New Approach to Improving the Outcome of Catheter Ablation of Persistent and Longstanding Persistent Atrial Fibrillation and an Efficient Heterogeneous Structure Weathering the Computation(2/2)

Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice. Due to its beingminimally invasive, safe, and relatively easy to perform with few complications, the procedure of catheterablation has become a prominent choice to terminate AF in addition to medication. The proceduretraditionally involves in isolation of the pulmonary veins (PVs) and is the mainstream non-pharmacologictherapy for AF. While PV isolation commonly performed in clinical practice around the world, the successrate of this procedure decreases significantly for patients with persistent AF (AF consistently occurs for morethan 7 days) and yet, no satisfactory improvement has been made by the physicians and researchers. Aplausible reason is as the atrial fibrillation persists, wide-distributed rapid discharging areas in combinationof multiple new evolving mechanisms might all contribute to maintain the presence of atrial fibrillation. Inthis case, the atrial electrogram will exhibit quite complicated and irregular patterns, termed complexfractionated atrial electrogram (CFAE). The CFAE eletrograms features non-stationary and nonlinearbehaviors diminishing frequency gradient (no distinct dominant frequency) and make frequency domainanalysis significantly more difficult to localize the ablation site. The multiple lead catheters cansimultaneously record data from different locations, and thus can provide both spatial and temporalinformation that help to reveal the electrical properties of the atrial matrix. Recent study documented theimportance of rotors in maintaining persistent AF. Identifying the pivot of rotor was well accepted to presentthe phase singularity (PS). However as the atrial fibrillation progressed from paroxysmal to persistent, theareas with CFAE electrograms occupied by high density of irregular wavebreaks can randomly cause the PS.Those issues will highly compromise the capability of phase mapping to identify rotors. In this project, weaim to combine the theory of complex systems and statistical physics with a non-contact 3 dimensionalguiding system to demonstrate the existence of “rotors” as one of the main causes of AF and to developanalytic tools such as the similarity index and recurrence plot to identify the AF sources. We use physicalconcepts such as the divergence and the curl (rotating force) of a vector field to describe the characteristics ofthe average wave propagation and also the gradient field of an entropy function to establish the existence andeffects of the rotor sources. In addition, through a heterogeneous computing structure we can incorporate theadvantages of various platforms and processors to achieve optimal computing efficiency. It is expected thatour procedures can be translated into an essential algorithm for AF ablation in the latest 3 dimensional guiding system.