Calcium dynamics and ventricular fibrillation.

To the Editor: Warren et al1 recently performed an optical mapping study in blood-perfused pig hearts. They concluded that their results did not support the presence of nonvoltage-gated intracellular calcium (Cai) transients during ventricular fibrillation (VF) and suggested that action potential (AP)/Cai transient dissociation is a consequence rather than a cause of wave fragmentation. A major piece of evidence in support of this conclusion is the failure of BAPTA-AM, a calcium chelator, in preventing VF in these pig hearts. These latter experiments were performed by …