Metabolism of the myocardium

2021-05-17 05:19 PM

This ATP in turn acts as the energy conveyors for heart muscle contraction and other cellular functions. In severe coronary ischemia, ATP lowers ADP, AMP, and adenosine first.

Under normal conditions, the myocardium uses fatty acids as the main source of energy (70%). However, when ischemia reaches the heart, the anaerobic hydrolysis of glucose to produce energy to maintain the heart's activity. Consuming a large amount of sugar and simultaneously producing lactic acid is one of the causes of myocardial ischemia and heart attack.

It is noteworthy that in other tissues, more than 95% of the metabolic energy released from foods is used to form ATP in the mitochondria. This ATP in turn acts as the energy conveyor for heart muscle contraction and other cellular functions. In severe coronary ischemia, ATP lowers ADP, AMP, and adenosine first. The myocardium is permeable to adenosine, so it diffuses from the myocardium into circulation.

The adenosine produced is one of the substances that cause dilation of the coronary arterioles in hypoxia. However, loss of adenosine also has serious cellular consequences. In severe coronary ischemia within as little as 30 minutes, as occurs after myocardial infarction, about half of the adenine base may be lost from the affected myocardium. Furthermore, this loss can be replaced by a new synthesis of adenine at a rate of only 2% per hour. Therefore, when a severe coronary ischemic attack persists for 30 minutes or more, ischemia may be too late to prevent injury and cell necrosis. This occurrence is almost certainly one of the main causes of myocardial cell necrosis during myocardial ischemia.