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Figure 1 Regional Difference in Ionic Current Contribution to APs
Differences in key ion currents between atrial (blue) and ventricular (red) action potentials (APs). Atrial APs have smaller AP amplitude and less negative resting membrane potential. Currents (green) identified above the line illustrating the APs are present in both regions; atrially expressed ionic currents are illustrated below the AP schematic (blue). IKACh = acetylcholine-regulated potassium current; IKur = ultrarapid delayed-rectifier potassium current; INa = sodium current.