Fig. 8.
AP waveform of the human atrial myocyte during late repolarization. A: late repolarization occurred more rapidly in the hAMr model compared with the model of Nygren et al. (40), as shown by the arrow. B: note that IK1 during late repolarization in the hAMr model was increased compared with the model of Nygren et al. (40). C: IKur during the late repolarization phase of the AP. The magnitude and time courses of IKur in the hAMr and Nygren et al. (40) models were very similar. D: modulation of the time course of late repolarization as a function of the relative conductance of gK1 and gKur. E: percent change in APD90 with changes in gK1 or gKur compared with nominal values (those used in the hAMr model). The relative size and time course of the two additional K+ currents active during late repolarization in the human atrial myocyte (IKr and IKs) are shown in F and G, respectively. Note the small density of these currents compared with IK1 and IKur in B and C.