**5. Future direction**

Because diagnosing MD can be challenging for clinicians, research is needed to better understand the complex bioenergetic arrangements and redox networks of the mitochondrion in cardiac cell. Improved understanding of mitochondrial mechanism in the pathophysiology in the heart will help the discovery of novel biomarkers and clinical diagnostic standards for the heart disease. In addition, current pharmacologic strategies are incompletely effective, and large randomized controlled trials are warranted to direct future therapy. Since HF is recognized as a state of myocyte energy starvation, greater evidence, in the form of large randomized, controlled trials, is required to confirm the role of metabolic-modulating drugs in the treatment of HF, which will be expected to be an area of great advances in the future. Additionally, more preclinical and clinical studies are necessary to evaluate the effectiveness and toxicity of mitochondrial-targeted antioxidants. Furthermore, the identification of the mechanisms by which alterations in substrate utilization cause cardiomyopathy is also a necessary area of intense research.
