The mitochondrial death pathway is a process of programmed cell death, also known as apoptosis, that is initiated by mitochondrial signaling events. In this pathway, mitochondrial outer membrane permeabilization (MOMP) leads to the release of pro-apoptotic factors, such as cytochrome c, from the mitochondrial intermembrane space into the cytosol, ultimately leading to activation of caspases and apoptosis. Cardiac myocyte apoptosis refers to the programmed cell death of heart muscle cells, or cardiomyocytes, through the mitochondrial death pathway. It is an important mechanism of cardiac injury in a variety of pathological conditions, including heart failure, ischemia-reperfusion injury, and cardiotoxicity from chemotherapy.