Fig. 5

Optical mapping in CD44^−/− mice. A Representative examples (left panel) and mean ± SE analysis (right panel) of optical action potential duration (APD) and calcium transient duration (CaTD) maps of wild-type (WT) and CD44^−/− mice at different pacing cycle length (PCLs). B Representative examples (left panel) and mean ± SE analysis (right panel) of ventricular tachyarrhythmia (VT) and delayed after depolarizations (DADs) in WT and CD44^−/− mice. In A and B, both were before and after isoproterenol (10 nmol/L) infusion. N = 13–14 mice for each group. In B, *P < 0.05 between groups by Fisher’s exact test. CD44^−/− = CD44 knock-out mice, ISO = isoproterenol, WT = wild-type mice, APD₉₀ = APD at 80% repolarization, CaTD₈₀ = CaTD at 80 repolarization, COV = coefficient of variance, PCL = pacing cycle length, VT = ventricular tachyarrhythmia, DAD = delayed afterdepolarization, n = number of mice for each group