Single and multiple early afterdepolarization caused by nickel in rat atrial muscle.

We examined the possible role of the Na-Ca exchange (NCX) in the arrhythmogenesis in rat atrial preparations applying microelectrode technique. In control Tyrode solution preparations isolated from the sinoatrial area contracted with frequency of 48+/-4 min(-1) (group I) or 84+/-7 min(-1) (group II). In preparation beating with low frequency partial inhibition of NCX by administration of Ni2+ (0.