INA and atrial fibrillation: Our simulation results are in agreement with previous studies showing decreased stability of rotors in the human atria due to IK1 and INa inhibition (Kneller et al., 2005; Ehrlich and Nattel, 2009; Pandit and Jalife, 2013) as well as variable efficacy of these pharmacological interventions in the conversion of AF, likely due to differences in underlying electrophysiological substrates.