explain the pathophysiology of Angina

Short answer: Decrease oxyhemoglobin circulation in the blood vessels that supply blood to the heart muscle.

PATHOPHYSIOLOGY OF ANGINA:

Increase in heart rate results in increased oxygen demand by the heart. The heart has a limited ability to increase its oxygen intake during episodes of increased demand. Therefore, an increase in oxygen demand by the heart (eg, during exercise) has to be met by a proportional increase in blood flow to the heart.

Myocardial ischemia can result from:

1. a reduction of blood flow to the heart that can be caused by stenosis, spasm, or acute occlusion (by an embolus) of the heart is arteries
2. resistance of the blood vessels
3. reduced oxygen-carrying capacity of the blood.

Atherosclerosis is the most common cause of stenosis (narrowing of the blood vessels) of the heart is arteries and, hence, angina pectoris. Some people with chest pain have normal or minimal narrowing of heart arteries; in these patients, vasospasm is a more likely cause for the pain, sometimes in the context of Prinzmetal is angina & syndrome X.

Myocardial ischemia also can be the result of factors affecting blood composition, such as reduced oxygen-carrying capacity of blood, as seen with seven anemia (low number of red blood cells), or long-term smoking.