Oita International Electrocardiology Symposium 2000 “Electrophysiology and Management of Lethal Arrhythmias in the New Millennium: From Genes to Bedside”

The ionic mechanisms underlying the slow diastolic depolarization have been studied by the voltage clamp experiments using myocytes dissociated from the sinoatrial node of various species. Recently, a new voltage-dependent inward current has been recorded at both the whole cell and the single channel levels. Since this inward current is activated by depolarization to a potential range of the slow diastolic depolarization, and is increased by the β-adrenergic stimulation, the current may take a pivotal role in the pacemaker depolarization. We briefly review the ionic mechanisms underlying the pacemaker depolarization of mammalian SA node cells.