PDK4 and atrial fibrillation: In addition, the expression levels of ERS axes, including caspase-12, CHOP, ATF4 (Figure 1B), p-elF2α and p-PERK (Figures 1C,D), and the Warburg effect markers, including LDHA, PDK-4 (Figure 1B) and lactic acid (Figure 1E), were increased in the LAA from AF patients compared with SR patients.