Angina

Angina pectoris is chest pain due to ischemia (a lack of blood and hence oxygen supply) to the heart muscle, generally due to obstruction or spasm of the coronary arteries (the heart's blood vessels). Coronary artery disease, the main cause of angina, is due to atherosclerosis of the cardiac arteries. The term derives from the Greek ankhon ("strangling") and the Latin pectus ("chest"), and can therefore be translated as "a strangling feeling in the chest".

Pathophysiology

Increases in heart rate result 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 (e.g., during exercise) has to be met by a proportional increase in blood flow to the heart.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Myocardial ischemia can result from:

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• a reduction of blood flow to the heart caused by the stenosis or spasm of the heart's arteries,
• resistance of the blood vessels, or
• reduced oxygen-carrying capacity of the blood.

Atherosclerosis (narrowing of the blood vessels) is the most common cause of stenosis of the heart's arteries and, hence, angina pectoris.

Related Topics:
Atherosclerosis - Stenosis

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Many people with chest pain have normal or minimal narrowing of heart arteries. This has shown that resistance of the blood vessels (abnormal constriction or deficient relaxation of heart vessels) can be responsible for as much as 95% of coronary artery resistance.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

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

Related Topics:
Blood - Anemia - Smoking

~ ~ ~ ~ ~ ~ ~ ~ ~ ~