Role of Heterogeneous Ionic Profiles in Atrial Fibrillation Propagation. A Population of Models Study.

Atrial fibrillation (AF) is characterized by irregular and discontinuous propagation in the atrial muscle. Experimental data show heterogeneity regarding ionic profiles throughout different regions of the atrium. In this study, the effect of the interaction of tissue with different ionic profiles is evaluated in terms of wave propagation. An experimentally calibrated population of AF profiles was generated. Ionic profiles fitting physiological biomarkers on 1Hz pacing protocols and capable of self-sustaining reentrant activity were evaluated. A bilayer rectangular mesh was simulated including the basal model and one of the population models $(N=144)$ . A functional reentry was started on the basal region and the wave propagation to the altered region was classified as Continuous Propagation (CP) or Wave Break (WB). Results showed 65 CP and 64 WB patterns. Regarding ionic variations, lower $I_{K}1,\ I_{Na}$ and higher $I_{Kur}$ were associated with WB. Considering biomarkers at 1 Hz, higher Resting Membrane Potentials, longer AP Duration and larger AP Amplitude are associated with WB. Differences in ionic profiles and AP biomarkers along the tissue result in irregular wavefront propagations. Characterization of ionic profiles can help to better reproduce those conditions observed in clinical and experimental practice.