After 3 min, while the drug diffused into the tissue layers, Ca2+ transient amplitude increased (Figure 2C) and, in line with the action of PKA on phospholamban (PLN) phosphorylation and enhanced SERCA-2 activity, the decay kinetics was accelerated, to a similar degree, in control and CPVT hearts. Here, PLN is linked to catecholaminergic polymorphic ventricular tachycardia.