Among the many differentially regulated genes in AF+HF LA were subunits encoding ion channels or their interacting proteins, such as potassium voltage-gated channel interacting protein 2 (KCNIP2), potassium calcium-activated channel subfamily N member 2, and calcium voltage-gated channel subunit alpha1 D (Supplemental Tables 4, 5, 8, and 9), which were expected based on previous studies associating these ion channels with AF (20, 47, 48). This evidence concerns the gene CACNA1D and atrial fibrillation.