Table 1

Parameters for Fitting UDB for 5-Hz Pulse Trains by Flecainide

	Concentration μM	n	τ_f(pulses⁻¹)	τ_s (pulses⁻¹)	A_s(×10⁻²)	base (×10⁻²)
	μm
WT	3	4	54.5 ± 4.6			87.4 ± 1.9
	10	4	16.6 ± 6.8 (n = 4)	87.7 ± 20 (n = 3)	82.7 ± 1.6	74.0 ± 1.1
	30	4	8.5 ± 0.9	54.7 ± 7.7	60.4 ± 1.7	42.6 ± 2.7
	100	4	4.1 ± 0.4	69.0 ± 24	42.0 ± 3.6	27.9 ± 2.7
	300	4	2.0 ± 0.11	49.5 ± 12	26.8 ± 1.7	19.5 ± 1.2
ΔKPQ	1	3	121 ± 31			82.5 ± 3.5
	3	5	88.3 ± 14			74.8 ± 0.9^*
	10	5	66.7 ± 4.7^*			47.8 ± 4.0^*
	30	5	49.9 ± 1.2^*			28.9 ± 1.4^*
	100	4	10.6 ± 0.5^*	31.9 ± 1.3	39.0 ± 1.8^†	14.9 ± 0.8^*
	300	4	4.8 ± 0.4^*	18.8 ± 2.6^†	26.8 ± 7.3^†	5.6 ± 0.6^*

The relative amplitude of peak I_Na was fit with a single-component (A_f × exp-t/τ_f + base), or two-component (A_f × exp-t/τ_f + A_s × exp-t/τ_s + base) decay: t, pulse number; τ_f and τ_s, time constants of fast and slow components; A_fand A_s, fractional amplitudes of fast and slow components. Single component fits are reported where the F -ratio did not support fitting with two components (see Materials and Methods), and the τ's for the single component fits were arbitrarily assigned to the τ_f column. n represents the number of experiments. Data = mean ± S.E. Significant difference compared with WT at P < .01 (*) and P < .05 (†).