ATF4 and atrial fibrillation: In a cellular AF model constructed by treating the mouse atrial myocyte HL-1 cells with rapid field stimulation, ATF4 was significantly induced accompanied with the decrease of cell viability, and overexpression of ATF4 further reduced the viability of HL-1 cells through inducing the expression of numerous genes related with amino acid biosynthesis, ER stress and cell death (Freundt et al., 2018).