Angina is classified as one of the following two types:
Stable angina
Unstable angina
Stable angina is the most common angina and the type most people mean when they say angina.
People with stable angina usually have angina symptoms on a regular basis. The episodes occur in a pattern and are predictable.
For most people, this involves angina symptoms after exertion such as climbing the stairs or running to catch an elevator.
Stable angina symptoms last less than 5 minutes.
They are usually relieved by rest or medication, such as nitroglycerin under the tongue.
Unstable angina is a less common type. Angina symptoms are unpredictable and often occur at rest.
This may indicate a worsening of stable angina, but sometimes the first time a person has angina it is already unstable.
The symptoms are worse in unstable angina, meaning the pains are more frequent, more severe, last longer, occur at rest, and not relieved by nitroglycerin under the tongue.
Unstable angina is not the same as a heart attack, but it warrants an immediate visit to your health care provider or a hospital emergency department. You may need to be hospitalized to prevent a heart attack.
If you have stable angina, any of the following may indicate worsening of your condition:
An angina episode that is different from your regular pattern
Being awakened at night by angina symptoms
More severe symptoms than usual
Having angina symptoms more often than usual
Angina symptoms last longer than usual
The most common cause for the heart not getting enough blood is coronary heart disease, also called coronary artery disease.
In this disease, the coronary arteries become blocked, narrowed, or otherwise damaged.
They can no longer supply the heart with all of the blood it needs.
Most cases of coronary heart disease are caused by atherosclerosis, also called "hardening of the arteries."
Atherosclerosis is a condition in which a fatty substance/cholesterol builds up inside the blood vessels.
These buildups are called plaques, and they can block blood flow through the vessel partly or completely. Multiple risk factors, especially diabetes, high blood pressure, smoking, and high cholesterol, accelerate this build up.
Another cause of unstable angina is coronary artery spasm.
Spasm of the muscles surrounding the coronary arteries causes them to narrow or close off temporarily. This blocks the flow of blood to the heart muscle for a brief time, causing angina symptoms.
This is called variant angina or Prinzmetal angina.
This is not the same as atherosclerosis, although some people have both conditions.
The symptoms often come on at rest (or during sleep) and without apparent cause.
Other causes of angina symptoms include the following:
Blockage of a coronary artery by a blood clot or by compression from something outside the artery
Inflammation or infection of the coronary arteries
Injury to one or more coronary arteries
Poor functioning of the tiny blood vessels of the heart (microvascular angina)
When a person has underlying atherosclerosis, spasm, or damage to the coronary arteries, angina symptoms usually are set off by one of the following "triggers":
Physical exertion or exercise
Emotional stress
Exposure to cold
Decreased oxygen content in the air you breathe, as when flying in an airplane or being at high altitude)
Using a stimulant, such as caffeine, or smoking a cigarette (which lowers the amount of oxygen in the blood)
Risk factors for atherosclerosis and angina include the following. Some of these are reversible.
High blood pressure (hypertension)
High levels of cholesterol and other fats in the blood
Diabetes
Smoking
Male sex
Inactive (sedentary) lifestyle
Family history of coronary heart disease
Aging
Regular use of stimulants, especially nicotine, cocaine, or amphetamines: Other stimulants include theophyllines, inhaled beta-agonists, caffeine, diet pills, and decongestants.
Circulatory System
Circulatory System, or cardiovascular system, in humans, the combined function of the heart, blood, and blood vessels to transport oxygen and nutrients to organs and tissues throughout the body and carry away waste products. Among its vital functions, the circulatory system increases the flow of blood to meet increased energy demands during exercise and regulates body temperature.
