Unstable angina is a condition in which your heart doesn't get enough blood flow and oxygen. It may lead to a heart attack.
Angina is a type of chest discomfort caused by poor blood flow through the blood vessels (coronary vessels) of the heart muscle (myocardium).
Coronary artery disease due to atherosclerosis is the most common cause of unstable angina. Atherosclerosis is the buildup of fatty material, called plaque, along the walls of the arteries. This causes arteries to become narrowed and less flexible. The narrowing interrupts blood flow to the heart, causing chest pain.
People with unstable angina are at higher risk of having a heart attack.
Rare causes of angina are:
Risk factors for coronary artery disease include:
Symptoms of angina may include:
With stable angina, the chest pain or other symptoms only occur with a certain amount of activity or stress. The pain does not occur more often or get worse over time.
Unstable angina is chest pain that is sudden and often gets worse over a short period of time. You may be developing unstable angina if the chest pain:
Unstable angina is a warning sign that a heart attack may happen soon and needs to be treated right away. See your doctor if you have any type of chest pain.
Tests for angina include:
Your doctor may want you to check into the hospital to get some rest, have more tests, and prevent complications.
Blood thinners (antiplatelet drugs) are used to treat and prevent unstable angina. You will receive these drugs as soon as possible if you can take them safely. Medicines include aspirin and the prescription drug clopidogrel or something similar. These medicines may be able to reduce the chance of a heart attack or the severity of a heart attack that occurs.
During an unstable angina event:
A procedure called angioplasty and stenting can often be done to open a blocked or narrowed artery
Heart bypass surgery may be done for some people. The decision to have this surgery depends on:
Unstable angina is a sign of more severe heart disease.
How well you do depends on many different things, including:
Abnormal heart rhythms and heart attacks can cause sudden death.
Unstable angina may lead to:
Seek medical attention if you have new, unexplained chest pain or pressure. If you have had angina before, call your doctor.
Call 911 if your angina pain:
Call your doctor if:
If you think you are having a heart attack, get medical treatment right away.
Some studies have shown that making a few lifestyle changes can prevent blockages from getting worse and may actually improve them. Lifestyle changes can also help prevent some angina attacks. Your doctor may tell you to:
Your doctor will also recommend that you keep other health conditions such as high blood pressure, diabetes, and high cholesterol levels under control.
If you have one or more risk factors for heart disease, talk to your doctor about taking aspirin or other medicines to help prevent a heart attack. Aspirin therapy (75 - 325 mg a day) or drugs such as clopidogrel, ticagrelor or prasugrel may help prevent heart attacks in some people. Aspirin therapy is recommended if the benefit is likely to outweigh the risk of side effects.
Accelerating angina; New-onset angina; Angina - unstable; Progressive angina
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Lange RA, Hillis LD. Acute coronary syndrome: unstable angina and non-ST elevation myocardial infarction. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 72.
Montalescot G, Cayla G, Collet JP, Elhadad S, Beyqui F, Le Breton H, et al. Immediate vs. delayed intervention for acute coronary syndromes: a randomized clinical trial. JAMA. 2009;302:947-954.
Anderson JL, Adams CD, Antman EM, et al. 2012 ACCF/AHA focused update incorporated into the ACCF/AHA 2007 guidelines for the management of patients with unstable angina/non-ST-elevation myocardial infarction. J Am Coll Cardiol. 2013;61(23):e179-347.
Updated by: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
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