Angina is chest pain going to happen?

The normal cycle of symptoms have great reserves forces in fierce physical activity, quiet coronary flow ratio increased 6 to 7 times, from quiet when 300 ml / min to 2000 ml / min, and activities to meet the needs of myocardial metabolism. When coronary atherosclerotic lesions occurred, luminal narrowing, the coronary blood flow for the rest or only minor activities of myocardial metabolism. So in a quiet state, not normally arise myocardial ischemia and hypoxia state, and an increase in cardiac load, such as fatigue, agitation, such as a meal or cold, increased myocardial oxygen demand, but it can not be like normal coronary case of compensatory expansion, or even react in case of spastic disorders, a result, a transient myocardial ischemia, triggered angina. Then angina chest pain symptoms is going to happen? Some people think that, myocardial ischemia in the circumstances, the local lactic acid, phosphoric acid and other acidic metabolites and histamine accumulation. These chemicals can stimulate local and imported nerve endings, the adoption of 1 ~ 4 thoracic sympathetic ganglion transmitted to the corresponding section of the spinal cord, the afferent spread to the cerebral cortex and produce pain. Visceral pain due to the spinal cord often reflected in the corresponding segments of the spinal nerve by the skin of regional distribution, reflected in the angina, chest pain is often, mainly located in the heart before or after the sternum area to the left shoulder and left forearm radiotherapy.