The heart contracts about 100,000 times a day and pumps about 7000 liters of blood into the aorta per day or about 2.6 million liters per year for a person weighing about 60 kg. Therefore, a large amount of energy (ATP) is consumed, which amounts to about 6 kg. If one assumes that a lifetime is 80 years, the heart contracts about 3 billion times, and its total output is equivalent to that of 1000 of 200,000-ton class tankers. The energy metabolism of myocardium, which produces ATP, is 60–90% dependent on fatty acid oxidation and 10–40% on glucose oxidation [1, 2]. The efficiency of utilization of these substrates, such as fatty acids and glucose, and the supply of oxygen used for oxidation of these substrates are important factors regulating myocardial energy metabolism. Factors that influence metabolic pathways directly related to ATP production, such as the TCA cycle and the electron transfer system, are also very important.