Although atherosclerosis is far and away the leading cause of angina, other conditions can impair the delivery of oxygen to the heart muscle and cause pain. Many conditions may cause chest pains unrelated to heart or blood vessel abnormalities. Stable angina responds well to medical treatment. Any event that increases oxygen demand can cause angina, including exercise, cold weather, emotional tension, and even large meals. Unstable angina is a much more serious situation and is often an intermediate stage between stable angina and a heart attack.
Medications are less effective in relieving pain of unstable angina.
A third type of angina, called variant or Prinzmetal's angina, is caused by a spasm of a coronary artery. It almost always occurs when the patient is at rest. Irregular heartbeats are common, but the pain is generally relieved immediately with treatment. Some people with severe coronary artery disease do not experience angina pain, a condition known as silent ischemia, which some experts attribute to abnormal processing of heart pain by the brain. Coronary artery disease is the leading killer in America of both men and women, responsible for over 475,000 deaths in 1996.