Energetics in the Hypertrophied and Failing Heart

The link between energy production and energy utilization is predominantly met by the creatine kinase (CK) phosphagen system. CK catalyses the transfer of a high-energy phosphoryl group from ATP to creatine to form phosphocreatine (PCr). This reversible reaction facilitates energy transfer by obviating the need for ATP diffusion, while high PCr levels provide an energy buffer when demand outstrips supply. Compartmentalization of CK isoenzymes to the mitochondria and cytosol maintain favorable levels of local metabolites to maximize the energy available from ATP hydrolysis. This chapter illustrates how all major components of the CK system are down-regulated in human and experimental heart failure and critically evaluates the contribution to disease pathophysiology. Regardless, there is growing evidence from experimental models that augmentation of the CK system may be beneficial in the ischaemic and failing heart.