What are the different types of angina?
Angina due to a decrease or lack of coronary artery blood flow
Angina is most often caused by narrowing of the coronary arteries because of atherosclerotic heart disease. There may be one or more arteries that are blocked and the amount of pain or other symptom severity is not necessarily related to the number of blood vessels blocked. Usually, there has to be at least a 50% narrowing of a coronary artery to cause symptoms.
Prinzmetal angina describes pain that is caused when a coronary artery goes into spasm temporarily decreasing blood supply to a section of heart muscle.
Microvascular angina describes narrowing of small arteries to cause areas of the heart to have decreased blood flow. The large coronary arteries may be normal.
Syndrome X cardiac disease describes decreased blood flow to the heart muscle with normal coronary arteries not caused by the vasospasm that is seen in Prinzmetal angina. This may be a variant of microvascular angina.
Rare causes may also include abnormalities that occur with the coronary arteries that are not due to ASHD including scarring that can occur from chest radiation, inflammation of the arteries because of underlying illness like systemic lupus erythematosus, scleroderma, and Kawasaki's disease, as well as congenital abnormalities affecting coronary artery anatomy.
Other causes of angina
- Poorly controlled high blood pressure (hypertension) can place significant strain on the heart muscle as it continues to pump blood, causing pain.
- Aortic stenosis describes the narrowed valve that controls blood flow from the left ventricle, the chamber of the heart that pumps blood to the body, into the aorta. If the valve narrows enough, decreased blood flow into the coronary arteries may be the cause of angina.
- Cardiomyopathy describes a variety of conditions where the heart muscle is unable to adequately pump blood to meet the body and the heart's oxygen needs. Ischemic cardiomyopathy, heart muscle that has been damaged by atherosclerotic heart disease, is the most common type of cardiomyopathy.
- Situations exist that can cause the body not to be able to meet the heart's demand for oxygen. These include anemia and poisonings.
- Other circumstances may occur where the heart's oxygen demand is increased and angina occurs. Oxygen demand increases when the heart is asked to pump harder and faster. Examples include tachycardias like atrial fibrillation or atrial flutter that are out of control, fevers, hyperthyroidism, and the stress of major illness, infection, and trauma.
Some causes for angina are multifactorial. For example, a patient with atherosclerotic heart disease may become acutely ill or injured, where a fever or anemia may compound the inability of narrowed blood vessels to deliver oxygen to heart muscle cells. Or a patient who abuses cocaine can increase heart rate plus cause coronary arteries to constrict, leading to angina.