651627.fig.004a
(a)
651627.fig.004b
(b)
Figure 4: Percentage increases in ±dP/dtmax and TR75 under combined effect of the pacing and ISO. (a) The percentage increases in ±dP/dtmax between the pacing of 420 beats/min and intrinsic heart rate without and with ISO treatment. (b) The percentage shortenings in TR75 between the pacing of 420 beats/min and intrinsic heart rate without and with ISO treatment. Data are mean ± SEM, hearts for each ISO concentration in each group. * or **   versus baseline.