**3. Mitochondria in heart diseases**

Although the pathophysiology of heart diseases is divergent, mitochondrial dysfunction appears to be a common mechanism that determines cardiac survival and function. Cardiac mitochondrial abnormalities include shifted metabolic substrate utilization, impaired mitochondrial ETC activity, increased formation of ROS, altered calcium homeostasis, and increased mPTP opening. Defects in mitochondrial structure and function have been found in association with cardiovascular diseases such as dilated and hypertrophic cardiomyopathy (DCM and HCM, respectively), cardiac conduction defects and sudden death, ischemic and alcoholic cardiomyopathy, and myocarditis. This section focuses on the changes of mitochondrial bioenergetics that are associated with cardiac survival and growth in heart diseases, including heart failure (HF), ischemia/reperfusion (I/R), pressure overload–induced cardiac hypertrophy and the cardiomyopathies in diabetes, and genetic mitochondrial diseases (MD).
