CAV3 and heart failure: Although Cav-3-dependent regulation of t-tubular ICa by PKA was lost in CAL myocytes, they showed an increased ratio of basal t-tubular ICa density to t-tubule ICa density in the presence of H-89 compared with sham myocytes (CAL: basal −5.9 ± 1.6 pA/pF and H-89 −1.7 ± 0.8 pA/pF; sham: basal −12.9 ± 3.0 pA/pF and H-89 −7.4 ± 1.6 pA/pF), indicating that the contribution of PKA to the maintenance of t-tubular ICa was augmented in heart failure.