Table 4.

Tonic and use-dependent block with 10 μM ranolazine obtained at different holding potentials in ventricular and atrial myocytes

	Tonic block, %		Use-Dependent Block, %
	Ventricular myocytes	Atrial myocytes	Ventricular myocytes	Atrial myocytes
Holding potential
−120 mV	0.9 ± 3.3*	4.1 ± 2.7†	21 ± 5	32 ± 2‡
−110 mV	0.6 ± 5.0*	5.3 ± 2.1†	31 ± 5	43 ± 5‡
−100 mV	3.1 ± 6.4*	6.8 ± 2.3†	47 ± 6	56 ± 5‡

Values are means ± SD; n = 10 ventricular myocytes and 5 atrial myocytes. Trains of 50-ms pulses to −30 mV with 250 ms at holding potentials between pulses were used.

^*Not significantly different from zero (P > 0.3).

^†Significantly different from zero (P < 0.05). In both cell types, tonic block was not significantly dependent on holding potential (P > 0.3 by ANOVA).

^‡Significantly different from the use-dependent block in ventricular cells at all holding potentials (P < 0.05). In both cell types, use-dependent steady-state block was significantly dependent on holding potential (P < 0.01 by single-factor ANOVA).