Figure 1. IKH current characteristics.
Recordings from a PV cardiomyocyte with IK1 and no time-dependent increasing inward component (A) and from a different PV cell (B) with clear time dependence (voltage protocol in inset). C, mean ± s.e.m. time-dependent current (IKH) density–voltage relations in LA and PV cardiomyocytes measured at the end of a 4 s pulse. IKH was significantly larger in PV (n = 26 and 27 cells for LA and PV, respectively). Inset: enlargement of outward-current component that cannot be appreciated on same scale as inward currents. D, activation time constants (τ, obtained by fitting current activation with mono-exponential functions, n = 10 cells each) of IKH were similar in both tissues and faster at more negative potentials. *P < 0.05; TP, test potential; ○, PV; •, LA cardiomyocytes.