A, APD prolongation and alternans in STZ-treated WT murine ventricular myocytes (n=16 cells from 7 animals). B, Arrhythmogenic AP remodeling in STZ was abolished by AIP (n=11 cells from 4 animals). C, APD prolongation was prevented in STZ-treated CaMKIIδ-S280A (n=22 cells from 6 animals). D, APD prolongation and alternans in STZ-treated CaMKIIδ-MMVV (n=17 cells from 6 animals). Nested t-test. E-F, AP remodeling was CaMKII-dependent and involved both hyperglycemia-dependent S280 O-GlcNAcylation (predominant mechanism) and Ang-II-dependent 281/2MM oxidation (n=total number of cells/animals is reported in the figure). Nested one-way ANOVA, followed by Dunnett’s multiple comparisons test.