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Figure 1 Effect of sotalol on action potential duration and left ventricular pressure transients during steady state pacing. In the baseline state, an increase in the pacing cycle length (from 400 to 1,000 ms) produced a 40% increase in the action potential duration and a reduction in peak (+)dP/dt. After sotalol, an increase in the pacing cycle length produced a greater (48%) increase in the action potential duration and the decline in (+)dP/dt was markedly attenuated. dP/dt = time derivative of pressure; PCL = pacing cycle length.