Health Library

Acute Coronary Syndrome

(ACS; Unstable Angina)

Definition

Acute coronary syndrome (ACS) is a term that describes symptoms related to poor blood flow to the heart muscle that lead to a heart attack. This results in chest pain or angina pectoris. This is a very serious condition. ACS is a life-threatening condition. If you think you have ACS seek immediate medical treatment.

Causes

ACS is caused by a sudden blockage of the coronary arteries. These blood vessels carry blood to the heart muscle. The blood flow to the heart muscle is either greatly reduced or completely blocked. This leads to heart muscle damage or death from a heart attack.

Blood clots are often the cause of the narrowing arteries. The narrowing most often happens from years of plaque build-up in an artery. This is called atherosclerosis.

Coronary Artery

Risk Factors

Risk factors that increase your chances of developing acute coronary syndrome include:

A family history of heart disease

You are a man over 45 years old or a woman over 55 years old

Being overweight or obese
Smoking
High cholesterol, especially high LDL ("bad") cholesterol, high triglycerides, and low HDL (“good”) cholesterol
High blood pressure
Diabetes
Being sedentary
Having angina, a previous heart attack, or other types of coronary artery disease

Symptoms

ACS is very serious. It requires immediate medical treatment. Contact your doctor if you experience any of these symptoms:

Angina—chest pain, pressure, tightness, burning, or other discomfort that may last a few minutes, go away, and then come back; often occurs after physical exertion, emotional stress, or eating a large meal
Unstable angina—often occurs at rest, while sleeping, or with very little exertion; can last 30 minutes or longer
Pain or discomfort in one or both arms, shoulders, the back, the neck, jaw, or stomach
Shortness of breath that accompanies chest pain occurs before it
Feeling light-headed or dizzy
Nausea and vomiting
Sweating

Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will be done. If you suspect ACS, call an ambulance. At the hospital, tests may include the following:

Electrocardiogram (ECG or EKG)
Nuclear heart scan—radioactive tracers outline heart chambers and major blood vessels leading to and from the heart
Cardiac catheterization —can determine pressure and blood flow in the heart's chambers, collect blood samples from the heart, and examine the arteries of the heart by x-ray
Blood tests to measure different enzymes that are released when cells in the heart muscle die, including:
- Troponin test—considered the most accurate test; can determine if a heart attack has occurred and how much new damage was done to the heart
- CK or CK-MB test—measures creatine kinase (CK) in the blood
- Myoglobin test—checks for the presence of myoglobin in the blood
Your doctor may need detailed pictures of your heart. These can be made with:
- Coronary angiography —produces images of blood flow through the heart; will show where there are blockages are
- Echocardiogram —a test that uses sound waves to create a moving picture of your heart
- Chest x-ray —images of the inside of the chest to assess heart size and show lung congestion and the presence of pneumonia

Treatment

If you are having a heart attack, doctors will:

Work quickly to restore blood flow to the heart
Closely monitor vital signs to detect and treat complications

To restore blood flow, the main treatments are:

Aspirin are given to all patients suspected of having acute coronary syndrome.

Anti-ischemic drugs, such as nitroglycerin are used to help relieve chest pain.

Beta blockers are given to slow the heart rate so it does not use too much energy.

Thrombolytic drugs are used to dissolve blood clots. When given soon after a heart attack begins, these drugs can limit or prevent permanent damage to the heart. To be most effective, they need to be given within one hour after the start of heart attack symptoms. Some thrombolytic drugs are:

Streptomycin
TPA

Platelet inhibitors keep the blockage from getting worse:

Eptifibatide
Tirofiban
Glycoprotein IIb/IIIa receptor antagonist

Angioplasty —a catheter is inserted into a blocked artery. A balloon is inflated and deflated. This will allow blood to flow again. A stent may be placed.
Coronary artery bypass surgery —arteries or veins are taken from other areas in your body. They are used to bypass the blocked arteries in your heart.
Oxygen is given to all patients.

Treating ACS with angiography and revascularization (restoring blood flow to the heart) may reduce the rate of being hospitalized again. But, the surgery may not reduce the rate of death or heart attack.

Prevention

To help reduce your chances of getting ACS, take the same heart-healthy lifestyle steps used to prevent other forms of coronary artery disease such as:

Eating a well-balanced diet that is low in saturated fats. The diet should also be rich in fruits, vegetables, and whole grains.

Exercising regularly.

If you smoke, quit.
Manage your diabetes, blood pressure, and cholesterol. This can include lifestyle changes and medication.

American College of Cardiology

http://www.acc.org/

American Heart Association

http://www.heart.org/

Canadian Cardiovascular Society

http://www.ccs.ca/

Heart and Stroke Foundation of Canada

http://www.heartandstroke.com/

Acute coronary syndrome. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php. Updated October 2, 2012. Accessed October 30, 2012.

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Anderson JL, Adams CD, et. al. ACC/AHA 2007 Guidelines for the Management of Patients With Unstable Angina/Non-ST-Elevation Myocardial Infarction. J Am Coll Cardiol. 2007;50;e1-e157.

Cohen M, Diez JE< Levine GN et al: Pharmacoiinvasive management of acute coronary syndrome: incorporating the 2007 ACC/AHA guidelines: the cATH(cardiac catherization and antithrombotic therapy in the hospital) Clinical Consensus Panel Report-III. J Invasive Cardiol. 2007:18:525-40.

Heart attack: Tips for recovering and staying well. Familydoctor.org website. Available at: http://familydoctor.org/online/famdocen/home/common/heartdisease/recovery/002.html. Updated January 2011. Accessed October 30, 2012.

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Walker CW, Dewley CA, Fletcher SF:Aspirin combined with clopidogrel (Plavix) decreases cardiovascular events in patients with acute coronary syndrome. Am Fam Physician. 2007;7:1643-5.

What is angina? National Heart, Lung, and Blood Institute website. Available at: http://www.nhlbi.nih.gov/health/dci/Diseases/Angina/Angina_Treatments.html. Updated July 1, 2011. Accessed October 30, 2012.

7/7/2007 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php: O'Donoghue M, Boden WE, Braunwald E, et al. Early invasive vs conservative treatment strategies in women and men with unstable angina and non-ST-segment elevation myocardial infarction: a meta-analysis. JAMA. 2008;300:71-80.

Last reviewed October 2012 by Michael J. Fucci, DO

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.