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TITLE Potassium Heterogeneity Between Ventricles as Substrate of Mother Rotor AUTHORS Hermenegild Arevalo and Natalia Trayanova ABSTRACT The mechanism underlying ventricular fibrillation (VF) is a wildly debated topic in cardiac research. One theory suggests that VF is the result of completely random, meandering waves. Several studies, though, have found that intrinsic regional differences in the ventricles can result in the formation of complex spatiotemporal organization that can drive VF. In an experimental study by Samie et al., a high frequency domain in the guinea pig left ventricle (LV) that drives the fibrillatory activity in the rest of the ventricle was found. Patch clamp studies showed that there is a difference in the expression of potassium channels between LV and RV. The authors hypothesized that this difference underlies the susceptability of the LV to the induction of a stable spiral wave. The goal of this project is to transplant Samie's characterization of the difference between LV and RV into our realistic 3D model of the rabbit ventricle. Based on the 2D studies performed by Samie et al., we expect to see the formation of a stable spiral wave in the LV and random, meandering waves in the RV. Data from this study will shed insight into the mechanisms that underlie VF.