Click on image to view larger version.

Figure 2 Effect of isoproterenol in the LQT2 model. d-Sotalol (d-Sot, 100 µmol/L) produced a preferential prolongation of the M cell APD and an increase in TDR. Isoproterenol (Iso, 100 nmol/L) in the continued presence of d-Sot initially prolonged (2 min) and then abbreviated the APD of the M cell to the control level (10 min), whereas the APD of epicardial cell was always abbreviated, resulting in a transient increase in TDR. APD = action potential duration; LQT2 = long QT syndrome 2; TDR = transmural dispersion of repolarization.