By using the rat model of early CKD, we discovered an EPI-predominant lengthening of the APD via a reduction of Ito currents in EPI cardiomyocytes secondary to downregulation of KChIP2 without alteration of Kv4.2, Kv4.3, and Kv1.4 protein expression. This evidence concerns the gene KCNIP2 and chronic kidney disease.