Acute coronary syndrome is a term used to describe a range of conditions associated with sudden, reduced blood flow to the heart.
One condition under the umbrella of acute coronary syndrome is myocardial infarction (heart attack) — when cell death results in damaged or destroyed heart tissue. Even when acute coronary syndrome causes no cell death, the reduced blood flow alters heart function and indicates a high risk of heart attack.
Acute coronary syndrome often causes severe chest pain or discomfort. It is a medical emergency that requires prompt diagnosis and care. Treatment goals include improving blood flow, treating complications and preventing future problems.
The signs and symptoms of acute coronary syndrome, which usually begin abruptly, include the following:
- Chest pain (angina) or discomfort, often described as aching, pressure, tightness or burning
- Pain radiating from the chest to the shoulders, arms, upper abdomen, back, neck or jaw
- Nausea or vomiting
- Shortness of breath (dyspnea)
- Sudden, heavy sweating (diaphoresis)
- Lightheadedness, dizziness or fainting
- Unusual or unexplained fatigue
- Feeling restless or apprehensive
While chest pain or discomfort is the most common symptom associated with acute coronary syndrome, signs and symptoms may vary significantly depending on your age, sex and other medical conditions. People who are more likely to have signs and symptoms without chest pain or discomfort are women, older adults and people with diabetes.
When to see a doctor
Acute coronary syndrome is a medical emergency, and chest pain or discomfort can indicate any number of serious, life-threatening conditions. Call 911 or get immediate emergency services to get a prompt diagnosis and appropriate care. Do not drive yourself to an emergency department.
Acute coronary syndrome usually results from the buildup of fatty deposits (plaques) in and on the walls of coronary arteries, the blood vessels delivering oxygen and nutrients to heart muscles.
When a plaque deposit ruptures or splits, a blood clot forms. This clot obstructs the flow of blood to heart muscles.
When the supply of oxygen to cells is too low, cells of the heart muscles can die. The death of cells — resulting in damage to muscle tissues — is a heart attack (myocardial infarction).
Even when there is no cell death, an inadequate supply of oxygen still results in heart muscles that don't work correctly or efficiently. This dysfunction may be temporary or permanent. When acute coronary syndrome doesn't result in cell death, it is called unstable angina.
The risk factors for acute coronary syndrome are the same as those for other types of heart disease. Acute coronary syndrome risk factors include:
- Older age (older than 45 for men and older than 55 for women)
- High blood pressure
- High blood cholesterol
- Cigarette smoking
- Lack of physical activity
- Unhealthy diet
- Obesity or overweight
- Family history of chest pain, heart disease or stroke
- For women, a history of high blood pressure, preeclampsia or diabetes during pregnancy
If you have signs or symptoms associated with acute coronary syndrome, an emergency room doctor will likely order several tests. Some tests may be performed while your doctor is asking you questions about your symptoms or medical history. Tests include:
- Electrocardiogram (ECG). This test measures electrical activity in your heart via electrodes attached to your skin. Abnormal or irregular impulses can indicate poor heart function due to a lack of oxygen to the heart. Certain patterns in electrical signals may indicate the general location of a blockage. The test may be repeated several times.
- Blood tests. Certain enzymes may be detected in the blood if cell death has resulted in damage to heart tissue. A positive result indicates a heart attack.
The information from these two tests — as well as signs and symptoms — may provide the primary basis for a diagnosis of acute coronary syndrome and may determine whether the condition can be classified as a heart attack or unstable angina.
Other tests may be ordered to characterize the condition more thoroughly, rule out other causes of symptoms, or combine diagnostic and treatment interventions.
- Coronary angiogram. This procedure uses X-ray imaging to see your heart's blood vessels. A long, tiny tube (catheter) is threaded through an artery, usually in your arm or groin, to the arteries in your heart. A liquid dye, which can be detected by X-rays, is sent through the tube to your arteries. Multiple X-ray images of your heart can reveal blockage or narrowing of the arteries. The catheter may also be used for treatments.
- Echocardiogram. An echocardiogram uses sound waves, directed at your heart from a wand-like device, to produce a live image of your heart. An echocardiogram can help determine whether the heart is pumping correctly.
- Myocardial perfusion imaging (MPI). This test shows how well blood flows through your heart muscle. A tiny, safe amount of radioactive substance is injected into your blood. A specialized camera detects the blood as it moves through your heart to reveal whether enough blood is flowing through heart muscles and where blood flow is reduced.
- Computerized tomography (CT) angiogram. A CT angiogram uses a specialized X-ray technology that can produce multiple images — cross-sectional 2-D slices — of your heart. These images can detect narrowed or blocked coronary arteries.
- Stress test. A stress test assesses how well your heart functions when you exercise — when your heart needs to work harder. In some cases, you may receive a medication to increase your heart rate rather than exercising. This test is only done when there is no evidence of acute coronary syndrome or another life-threatening heart condition when you are at rest. During the stress test, heart function may be assessed by an ECG, echocardiogram or myocardial perfusion imaging.
Immediate treatment goals are to relieve pain and distress, improve blood flow, and restore heart function as quickly and as best as possible. Long-term treatment goals are to improve overall heart function, manage risk factors and lower the risk of a heart attack. A combination of drugs and surgical procedures may be used to meet these goals.
Depending on your diagnosis, medications for emergency care or ongoing management — and in some cases both — may include the following:
- Thrombolytics, also called clot busters, help dissolve a blood clot that's blocking an artery.
- Nitroglycerin improves blood circulation by temporarily widening blood vessels.
- Antiplatelet drugs, which help prevent blood clots from forming, include aspirin, clopidogrel (Plavix), prasugrel (Effient) and others.
- Beta blockers help relax your heart muscle and slow your heart rate, thereby decreasing the demand on your heart and lowering your blood pressure. These include metoprolol (Lopressor), nadolol (Corgard) and several others.
- Angiotensin-converting enzyme (ACE) inhibitors expand blood vessels and improve blood flow, allowing the heart to work more easily and efficiently. They include lisinopril (Prinivil, Zestril), benazepril (Lotensin) and several others.
- Angiotensin receptor blockers (ARBs), which help control blood pressure, include irbesartan (Avapro), losartan (Cozaar) and several others.
- Statins lower the amount of cholesterol circulating in the blood and may stabilize plaque deposits, making them less likely to rupture. Statins include atorvastatin (Lipitor), simvastatin (Zocor) and several others.
Surgery and other procedures
If medications aren't enough to restore blood flow to your heart muscles, your doctor may recommend one of these procedures:
- Angioplasty and stenting. In this procedure, your doctor inserts a long, tiny tube (catheter) into the blocked or narrowed part of your artery. A wire with a deflated balloon is passed through the catheter to the narrowed area. The balloon is then inflated, opening the artery by compressing the plaque deposits against your artery walls. A mesh tube (stent) is usually left in the artery to help keep the artery open.
- Coronary bypass surgery. With this procedure, a surgeon takes a piece of blood vessel (graft) from another part of your body and creates a new route for blood that goes around, or bypasses, a blocked coronary artery.
If you experience the sudden onset of chest pain or other symptoms of acute coronary syndrome, get emergency care immediately or call 911.
Your description of symptoms provides important information to help an emergency medical team make a diagnosis. Be prepared to answer the following questions.
- When did signs or symptoms appear?
- How long did they last?
- What symptoms are you currently experiencing?
- How would you describe the pain?
- Where is the pain located?
- How would you rate the severity of pain?
- Does anything worsen or lessen the symptoms?
An important step to prevent a heart attack is to make changes in your lifestyle that promote heart health and lower your risk of heart disease. These interventions include the following:
- Don't smoke. If you smoke, quit. Talk to your doctor if you need help quitting. Also, avoid second-hand smoke.
- Eat a heart-healthy diet. Eat a diet with lots of fruits and vegetables, whole grains, and moderate amounts of low-fat dairy and lean meats.
- Be active. Get regular exercise and stay physically active. If you have not been exercising regularly, talk to your doctor about the best exercise to begin a healthy and safe routine.
- Check your cholesterol. Have your blood cholesterol levels checked regularly at your doctor's office. Avoid high-fat, high-cholesterol meat and dairy. If your doctor has prescribed a statin or other cholesterol-lowering medication, take it daily as directed by your doctor.
- Control your blood pressure. Have your blood pressure checked regularly as recommended by your doctor. Take blood pressure medicine daily as recommended.
- Maintain a healthy weight. Excess weight strains your heart and can contribute to high cholesterol, high blood pressure, diabetes, heart disease and other conditions.
- Manage stress. To reduce your risk of a heart attack, reduce stress in your day-to-day activities. Rethink work habits and find healthy ways to minimize or deal with stressful events in your life. Talk to your doctor or a mental health care professional if you need help managing stress.
- Drink alcohol in moderation. If you drink alcohol, do so in moderation. Drinking more than one to two alcoholic drinks a day can raise blood pressure.