Angina or angina pectoris, meaning squeezing of the chest, is a chest pain and discomfort that usually occurs when a part of your heart muscle receives decreasing blood oxygen supply. It is often described as pressure, squeezing, burning or thightness in the chest. It usually starts behind the breastbone. Different parts of the body like arms, shoulders, jaw, throat, or back can occur pain. Angina is not a disease, but rather a symptom of coronary artery disease. The lack of oxygen rich blood to the heart is usually a result of narrower coronary arteries due to atherosclerosis. There are four classifications of angina- stable, unstable, variant, and microvascular.
Stable angina is the most common. It is brought on when the heart is working harder than usual. It can be predicted to happen over months or even years. It is usually relieved by rest and medication.
Variant angina (prinzmetal's) and microvascular are very rare. These can occur without any underlying coronary artery disease. This is due to abnormal narrowing of the blood vessels, reducing blood flow to the heart. They are usually relieved by medicine.
It is increasingly difficult for oxygen rich blood to reach the heart muscle as these arteries become too narrow.