Biophysical properties of INa at close-to-physiological conditions determined in the VC and VC/CC configurations in HEK cells and in rabbit ventricular myocytes.

Mean±SEM, ‘n’ indicates number of cells measured. V1/2, membrane potential for half-maximal (in)activation; k, slope factor of steady-state (in)activation curve; τf and τs, fast and slow time constant of recovery from inactivation, respectively; Af and As, fractions of fast and slow recovery from inactivation, respectively; 1-Peak INa (P2/P1), fraction of channels that entered into slow inactivation with a P1 of 1 s;*Pt-test.