Types of Angina

There are two main kinds of angina—common or stable angina and unstable angina. Both kinds of angina mean an increased risk of heart attack, but unstable angina is often a major warning sign that a heart attack can happen soon.

People with common or stable angina have episodes of chest discomfort that usually occur in an expected pattern. Common angina occurs when you are exerting more than usual activity (such as running to catch a bus) or are under mental and emotional stress. The level of activity or stress that causes the angina is somewhat predictable, and the pattern changes only slowly. Resting or relaxing usually eases the discomfort.

Unstable angina, instead of appearing gradually, may first appear as a very severe episode or as frequently recurring bouts of angina. The chest pain of unstable angina is unexpected and usually occurs at rest, or may wake a person in the night. Sometimes an established stable pattern of angina may change sharply. For example, it may be provoked by far less exercise than in the past. Unstable angina should be treated as an emergency because it can lead quickly to a heart attack, dangerous heart rhythms, or even sudden death.

There are two other forms of angina. One, Prinzmetal's or variant angina, is quite rare, but causes discomfort almost always when a person is at rest. It is caused by a spasm that narrows the coronary artery and lessens the flow of blood to the heart. The other is called microvascular angina. This type of angina occurs in people who have chest pain but have no apparent coronary artery blockage. The pain from microvascular angina results from poorly functioning blood vessels. Microvascular angina can be treated with the same medicines as common angina.