Chest pain that occurs due to lack of blood flow to the heart is known as angina; when the pain's level, frequency, and duration increase and become more unpredictable, this is known as unstable angina. The key difference between stable and unstable angina is that the stable variety is typically set off by a known trigger, such as stress or exercise, whereas the unstable type may happen at any time for no particular reason. People whose angina changes from stable to unstable should be concerned, and it can often be a sign of an impending heart attack.
When a person develops unstable angina, he or she will often notice chest pain occurring at times when it previously did not; for example, pain may come on while resting, even waking the person from sleep at night. Usually the attacks will happen more often than in the past, and the pain may be more intense. The duration of each attack will also usually increase, with periods of pain that may last over 20 minutes at a time. Medication such as nitroglycerin, which may have helped alleviate the pain previously, often become less effective.
Stable angina usually occurs due to a partial blockage of a coronary artery by deposits on the walls known as plaques. Many times it is the rupture of one of these plaques which leads to unstable angina. Often the rupture is accompanied by a blood clot which may further obstruct the blood vessel, decreasing blood flow to the heart even more. The risk that the clot may cause a complete obstruction, leading to a heart attack, is very great in these cases.
To diagnose unstable angina, a doctor will typically want to know the patient's history and if his or her symptoms have changed. A physical examination will also be done, to check blood pressure and heartbeat for any abnormalities. Blood may be analyzed to see if certain enzyme levels indicate the issue. Tests including electrocardiogram (ECG), a computed tomography (CT) scan, or an echocardiogram may be used to provide detailed analysis of the state of the heart and arteries.
The first line of treatment for unstable angina is usually a variety of drugs aimed at stabilizing the situation and preventing future problems. Blood thinners are commonly prescribed to avoid heart attack and treat the clot. Other drugs for blood pressure control, lowering cholesterol, or stabilizing heart rhythm may also be necessary. Surgery such as angioplasty or stenting may also be recommended to open up blocked arteries.