Merck Manuals, an online medical library, reports that angina occurs when the heart's workload and oxygen needs are not being met. The Mayo Clinic reports that angina causes chest pain, and pressure, squeezing, or heaviness in the chest. Angina is a symptom of coronary artery disease, and there are several types of this condition.
Stable Angina
According to the National Heart Lung and Blood Institute, stable angina is the most common form of angina. The pain of stable angina is due to the heart working harder than normal, such as during times of strenuous exercise or stress. Additionally, the pain of stable angina occurs according to a regular pattern, such as when running or climbing stairs. The pain usually lessens during rest or after taking prescribed medication.
Unstable Angina
Unstable angina is more serious than stable angina, according to Merck Manuals. In this form of angina, the types of activities that cause angina pain are not very predictable. For example, if climbing stairs caused a man's angina pain one day, but walking caused it the next day, he would have unstable angina. Other changes that are indicative of unstable angina are changes in the severity of pain, or frequency of the attacks. Merck Manuals notes that unstable angina is an acute coronary syndrome, and the risk of heart attack with this type of angina is high. The National Heart Lung and Blood Institute reports that this type of angina requires emergency medical treatment.
Variant Angina
According to the Mayo Clinic, another type of angina is variant angina, also called Prinzmetal's angina. This type of angina is quite rare, and is due to a spasm of the coronary artery. The National Heart Lung and Blood Institute adds that the pain of variant angina usually occurs between midnight and early morning, and can be quite severe. Fortunately, this type of angina pain usually responds quite well to medication.
Microvascular Angina
The National Heart Lung and Blood Institute reports that microvascular angina can last longer and be more severe than other types of angina. Microvascular angina may not respond well to medication. Furthermore, it may be a symptom of coronary microvascular disease, in which the very small vessels of the cardiovascular system are damaged.
