Angina also can be a symptom of coronary microvascular disease (MVD). This is heart disease that affects the heart’s smallest coronary arteries. In coronary MVD, plaque doesn't create blockages in the arteries like it does in CHD.

Studies have shown that coronary MVD is more likely to affect women than men. Coronary MVD also is called cardiac syndrome X and nonobstructive CHD.

Types of Angina

The major types of angina are stable, unstable, variant (Prinzmetal's), and microvascular. Knowing how the types differ is important. This is because they have different symptoms and require different treatments.

Stable Angina
Stable angina is the most common type of angina. It occurs when the heart is working harder than usual. Stable angina has a regular pattern. (“Pattern” refers to how often the angina occurs, how severe it is, and what factors trigger it.)

If you have stable angina, you can learn its pattern and predict when the pain will occur. The pain usually goes away a few minutes after you rest or take your angina medicine.

Stable angina isn't a heart attack, but it suggests that a heart attack is more likely to happen in the future.

Unstable Angina
Unstable angina doesn't follow a pattern. It may occur more often and be more severe than stable angina. Unstable angina also can occur with or without physical exertion, and rest or medicine may not relieve the pain.

Unstable angina is very dangerous and requires emergency treatment. This type of angina is a sign that a heart attack may happen soon.

Variant (Prinzmetal's) Angina
A spasm in a coronary artery causes this type of angina. Variant angina usually occurs while you're at rest, and the pain can be severe. Very little is known about this type of angina because it can be diagnosed as something else so easily.