Heart failure (HF) is a complex pathophysiologic state in which delivery of blood and nutrients is inadequate for tissue requirements. HF almost always arises in patients with previous cardiovascular disease such as acute myocardial infarction, atherosclerosis, cardiomyopathy, myocarditis, congenital malformations, or valvular disease. Recently, substantial progress has been made to understand the etiology, pathogenesis, and mechanisms of HF. Several inter-related mechanisms such as oxidative stress, signal transduction, abnormalities in intracellular calcium handling, mitochondrial dysfunction and inherited mutations have been proposed as the triggers of HF.