Cardiac hypertrophy is a compensatory mechanism, allowing the heart to maintain sufficient cardiac output in the context of elevated afterload. However, sustained pressure overload such as caused by hypertension or aortic stenosis eventually leads to maladaptive cardiac remodelling and ultimately to heart failure. Our lab has shown that activation of the AMP-activated protein kinase (AMPK) prevents cardiac hypertrophy development by decreasing O-GlcNAcylation, a post-translational modification which is shown to rapidly increase in cardiac hypertrophy and heart failure. The AMPK-mediated inhibition of protein O-GlcNAcylation is due to the direct phosphorylation and inhibition of Glutamine:fructose-6-phosphate amidotransferase (GFAT), the rate limiting step of the hexosamine biosynthesis pathway, the metabolic pathway responsible for the formation of the O-GlcNAc moiety. By using different types of AMPK activators and genetic model of AMPK-deficient mice, we recently investigated wheter AMPK activation could reverse the development of cardiac hypertrophy when already installed and could prevent heart failure evolution. By using mass spectrometry-based O-GlcNacylomic technologies, we also identified the putative O-GlcNAcylated candidate(s) responsible for the development of the disease and targeted by AMPK activation.