Fig. 1 (A) Average current voltage relations of peak I_Na in Con (n=10), nAF (n=7) and cAF (n=9) cells using protocol shown on left. (B) Average current density relations of peak I_Na in Con, nAF and cAF cells. *P<0.05 nAF, cAF versus Con. (C,D) Capacitance-subtracted peak I_Na in a typical Con and cAF cell. Holding potential, −100 mV. From: Density and function of inward currents in right atrial cells from chronically fibrillating canine atria Cardiovasc Res. 2002;54(2):405-415. doi:10.1016/S0008-6363(02)00279-1 Cardiovasc Res | Copyright © 2002, European Society of Cardiology

Fig. 3 (A) Currents tracings in Con (a), nAF (b), and cAF (c) cell under conditions of these experiments: Ca²⁺ 3 mM–EGTAi 10 mM; ryanodine 2 μM; holding voltage, −70 mV to various test voltages. Arrow indicates zero current level. (B) Average peak I_CaL density in Con (n=25), nAF (n=11) and cAF (n=6) cells. *P<0.05 versus Con. All data collected at same time after establishing whole cell configuration (Con, 15.0±0.5 min; nAF, 16.5±0.7 min; and cAF, 17.5±0.8 min P>0.05). (C) Average first and second time constants (τ₁ and τ₂) of decay of peak I_CaL in all cells of the three groups. A₁/A_total were 0.75±0.02, 0.79±0.03, 0.76±0.04 in Con, nAF and cAF cells, respectively (P>0.05). Inset shows first 150 ms of tracings from Con, nAF and cAF cells, each normalized to peak and superimposed to illustrate time course of peak current decay. From: Density and function of inward currents in right atrial cells from chronically fibrillating canine atria Cardiovasc Res. 2002;54(2):405-415. doi:10.1016/S0008-6363(02)00279-1 Cardiovasc Res | Copyright © 2002, European Society of Cardiology

Fig. 6 (A) The fraction of current remaining at the end of the clamp step (I₂₅₀) normalized to the peak current (I_max) for peak Ba²⁺ currents in the three different groups. Height of bar denotes average I₂₅₀ normalized to I_max. I₂₅₀/I_max is significantly less in cAF group when compared to either Con or nAF values suggesting that Ba²⁺ current decay is accelerated in cAF cells (see Fig. 5C). (B) The average I₂₅₀/I_max for several test voltages (V_t) under these same recording conditions for cells in each group. P<0.05 cAF versus Con curve. From: Density and function of inward currents in right atrial cells from chronically fibrillating canine atria Cardiovasc Res. 2002;54(2):405-415. doi:10.1016/S0008-6363(02)00279-1 Cardiovasc Res | Copyright © 2002, European Society of Cardiology

Fig. 5 (A) Currents tracings in Con (a), nAF (b), and cAF (c) cell under conditions of these experiments; Ba²⁺ 3 mM/BAPTAi 10 mM; ryanodine, holding voltage, −70 mV to various test voltages. Arrow indicates zero current. (B) Average peak I_BaL density voltage relations in Con (n=16), nAF (n=5) and cAF (n=12) cells. Data were all obtained at same time after establishing whole cell configuration (Con, 18.53±0.58 min, nAF, 19.8±1.2 min and cAF 17.9±0.5 min). Note that Con and nAF have comparable peak I_BaL densities under Ba²⁺/BAPTA conditions while cAF density remains different from Con and nAF. *P<0.05 cAF versus Con, nAF. (C) Typical Con, nAF and cAF peak I_BaL tracings under Ba²⁺/BAPTA conditions. Each has been normalized and superimposed to emphasize the differences in current decay between cells from the different groups. Note that the small Ba²⁺ currents of cAF cells decay more completely during the step depolarization. In (D) the bar graph illustrates the average time for peak current decay to T_0.8max, T_0.7max, T_0.6max, for cells in each group. *P<0.05 Con versus cAF, **P<0.05 nAF versus cAF. Note one Con cell never decayed to 0.6 max during the step depolarization and therefore its value was not included in average at T_0.6max. From: Density and function of inward currents in right atrial cells from chronically fibrillating canine atria Cardiovasc Res. 2002;54(2):405-415. doi:10.1016/S0008-6363(02)00279-1 Cardiovasc Res | Copyright © 2002, European Society of Cardiology

Fig. 2 Time course of recovery from inactivation of I_Na using the protocol shown in inset (B). (A) Recovery for cells in Con, nAF and cAF. I_Na at a certain interpulse interval (IPI) is normalized to I_max (at IPI=3000 ms) and plotted against IPI. (B) Average recovery curves for all groups for short IPIs. Note the slow recovery at short IPIs in both nAF and cAF cells. *P<0.05 Con versus nAF or Con versus cAF. From: Density and function of inward currents in right atrial cells from chronically fibrillating canine atria Cardiovasc Res. 2002;54(2):405-415. doi:10.1016/S0008-6363(02)00279-1 Cardiovasc Res | Copyright © 2002, European Society of Cardiology

Fig. 4 (A) Currents tracings in Con (a), nAF (b), and cAF (c) cell under conditions of these experiments; Ba²⁺ 3 mM–EGTAi 10 mM, ryanodine 2 μM; holding voltage, −70 mV to various test voltages. Arrow indicates zero current. (B) Inset shows peak I_BaL tracings during step depolarization in a Con, nAF and cAF cell each normalized to peak and superimposed to illustrate differences in current decay in cells of each group. Bar graph illustrates the average time for current decay to 80, 70, 60 and 50% maximum (T_0.8max, T_0.7max, T_0.6max, T_0.5max, respectively) for Con (n=6), nAF (n=5), cAF(n=7). There were no significant differences among groups. (C) Fraction of Ba²⁺ current remaining at I₂₅₀ normalized to I_max current for cells of the three groups. Height of bar denotes average value for each of three groups. There was no significant difference in I₂₅₀/I_max of peak currents under these recording conditions even though peak current densities differed. From: Density and function of inward currents in right atrial cells from chronically fibrillating canine atria Cardiovasc Res. 2002;54(2):405-415. doi:10.1016/S0008-6363(02)00279-1 Cardiovasc Res | Copyright © 2002, European Society of Cardiology