Circulatory system

What is angina?

A symptom of coronary artery disease, angina is characterized by chest pain that occurs when the heart muscle does not get enough blood. Angina pain feels like pressure or a squeezing in the chest. Pain may also occur in the shoulders, arms, neck, jaw, or back. Some patients report a pain that feels like indigestion or heartburn.¹

The most common type of heart disease, coronary artery disease occurs when plaque builds up in the coronary arteries, leading to artherosclerosis. As plaque accumulates, coronary arteries become narrow and stiff and blood flow to the heart is reduced. As a result, oxygen supply to the heart muscle decreases.²

Types of angina

It is vitally important to know the differences between the three types of angina:³

Stable angina
The most common type of angina, stable angina occurs when the heart is working harder than normal. Features of stable angina include:

• A regular pattern—after repeated bouts of angina, patients can usually recognize the pattern and predict when the next episode will occur.
• Pain usually subsides after a few minutes following rest and/or the use of angina medications.
• Although stable angina is not a heart attack, those suffering from stable angina are more likely to suffer a heart attack in the future.

Unstable angina
An indication that a heart attack could occur very soon, unstable angina is serious medical condition that requires immediate medical attention. Unlike stable angina, unstable angina is not characterized by a regular pattern and can occur without physical exertion. Pain is not relieved by rest or medication.

Variant angina
A rare condition, variant angina usually occurs when the patient is at rest. Pain can be severe, occurring between midnight and early morning. This pain is often relieved by medication.

It's important to remember that not all chest pain or discomfort is caused by angina. Chest pain may also be caused by heart attack, lung or respiratory problems (such as asthma or blood clot, for example), heartburn or a panic attack. Nevertheless, anyone experiencing chest pain should seek prompt medical attention.

What causes angina?

As mentioned earlier, angina is the result of reduced blood flow to the heart. It is most often due to coronary artery disease, although other types of heart disease or uncontrolled high blood pressure may also contribute to the development of angina.

In coronary artery disease, the coronary arteries that carry oxygen-rich blood to the heart muscle are narrowed due to the accumulation of fatty deposits known as plaque. This buildup of plaque is known as artherosclerosis. Plaque may be hard and stable, leading to narrow and hardened arteries, or it may be soft and likley to break open, causing blood clots. Whether hard or soft, plaque can cause angina by narrowing the artery, severely impeding blood flow, and by causing clots that can partially or completely obstruct the artery.⁴

Stable angina
The pain and discomfort of stable angina are most commonly the result of physical exertion. Severely narrowed arteries may allow enough blood to reach the heart when demand for oxygen is low, but with exertion (i.e. walking up a hill or climbing stairs), the heart works harder and the demand for oxygen increases. Other causes of stable angina include emotional stress, exposure to extreme hot or cold, heavy meals, and smoking.⁵

Unstable angina
Unstable angina is the result of clots that either partially or completely obstruct an artery. Blood clots can form if plaque in an artery ruptures or breaks open. Clots can create a larger blockage, with clots becoming large enough to completely block the artery and cause a heart attack. Clots can form, partially dissolve and form again. Pain occurs whenever there are clots block an artery.⁶

Variant angina
Spasms in a coronary artery cause the artery to tighten, thereby leading to variant angina. Spasms narrow the coronary artery, slowing or stopping blood flow to the heart. Variant angina can affect people with or without coronary artery disease. Spasms of the coronary artery may also be caused by emotional stress, exposure to cold, vasoconstricting medications (medications that narrow or constrict blood vessels), smoking, and cocaine use.⁷

Who's at risk?

People with coronary artery disease and those who have suffered a previous heart attack are more likely to develop angina. Unstable angina occurs most commonly in older adults. Variant angina is rare, occuring in only 2 percent of angina patients. Those affected by variant angina are often younger than those affected by other forms of angina.⁸

Signs and symptoms of angina

The pain and discomfort of angina are often described as pressure, squeezing, burning or tightness in the chest. Pain usually begins behind the breastbone and may also occur in the arms, shoulders, neck, jaw, throat or back. Pain may feel like heartburn or indigestion. Some patients claim the discomfort of angina is difficult to describe because it's hard to pinpoint the source of the pain. Symptoms such as nausea, fatigue, shortness of breath, light-headedness or weakness may also occur.⁹

Symptoms vary depending on the type of angina.

Stable angina
In stable angina, pain or discomfort:

• occurs when the heart must work harder, usually during physical exertion;
• is expected, and episodes of pain tend to be alike;
• usually lasts a short time (5 minutes or less);
• is relieved by rest or angina medicine;
• may feel like gas or indigestion; and
• may feel like chest pain that spreads to the arms, back, or other areas.

Unstable angina
In unstable angina, pain or discomfort:

• often occurs at rest, while sleeping at night, or with little physical exertion;
• is unexpected;
• is more severe and lasts longer (as long as 30 minutes) than episodes of stable angina;
• is usually not relieved with rest or angina medicine;
• may get continuously worse; and
• may signal the onset of a heart attack.

Variant angina
In variant angina, pain or discomfort:

• usually occurs at rest and during the night or early morning hours;
• tends to be severe; and
• is relieved by angina medicine.

Diagnosis

To determine whether you have angina, your doctor will do a physical examination and ask you about your symptoms. In order to determine your risk factors, he or she will also ask whether you have a family history of coronary artery disease or other heart disease. In some cases, a doctor can diagnose angina by noting patients' symptoms and how these symptoms occur. More commonly, however, doctors require additional tests in order to diagnose angina:

Electrocardiogram (ECG or EKG)
An electrocardiogram measures the rate and regularity of a patient's heartbeat.

Exercise stress test
An exercise stress tests shows how effectively the heart pumps at higher levels of exertion when the demand for oxygen is high. Readings from blood pressure tests and electrocardiograms are taken before, during, and after exercise to determine how the heart responds to execise. The first blood pressure reading and electrocardiogram are done to get a baseline. Readings are then taken as patients walk on a treadmill, pedal a stationary bicycle, or receive medication that increases heartbeat. The test continues until you reach a predetermined heart rate as set by your doctor. If you experience chest pain or a very sharp rise in blood pressure during the test, the test will end. Monitoring will continue for 10 to 15 minutes after completion of the test or until your heart rate returns to baseline.¹⁰

Chest x-ray
A chest x-ray is a picture of the heart, lungs, blood vessels and other organs and structures inside the chest. An x-ray will reveal abnormalities in your heart's shape and will also show whether it is enlarged. Either of these can be an indication of heart disease.

Nuclear heart scan
A nuclear heart scan shows blood flow to the heart and also reveals any damage to the heart muscle. Radioactive dye such as technetium or thallium is injected into the bloodstream. A specialized camera can see the dye and identify areas of low blood flow. Nuclear heart scans are usually conducted while you are at rest and again after exercise. Patients unable to exercise receive medications that increase heart rate. The two nuclear heart scans — before and after—are then compared.¹¹

Echocardiogram
An echocardiogram uses sound waves to create a picture of the heart. More detailed than an x-ray, the echocardiogram shows how well the heart chambers fill with blood and pump it to the rest of the body. An echocardiogram can also help identify areas of poor blood flow to the heart, areas of the heart muscle that are not contracting normally, and any prior injury to the heart caused by poor blood flow.¹²

Cardiac catheterization
In cardiac catheterization, a thin flexible catheter is passed through an artery in the groin or arm to reach the coronary arteries. This allows the doctor to determine pressure and blood flow to the chambers of the heart. It also allows the doctor to collect blood samples from the heart and to examine the arteries of the heart by x-ray.¹³

Coronary angiography
Conducted in conjuction with cardiac catheterization, coronary angiography involves the injection of dye into the catheter. Dye in the coronary arteries allows the doctor to see flow of blood through the heart and to determine where there are blockages.¹⁴

Your doctor may also request blood tests to check your blood cholesterol levels, blood sugar levels, levels of C-reactive protein and hemoglobin levels.

Treatment of angina

Treatment of angina includes medication, surgery, rehabilitation and changes to lifestyle. Treatment aims to reduce the frequency and severity of symptoms while striving to prevent or lower the risk of heart attack and death.

If symptoms are mild and not progressing, angina medication and changes in lifestyle may be all that's needed. However, unstable angina is a serious, emergency medical condition that requires hospitalization.

Lifestyle changes
To avoid future episodes of angina, it is necessary to change lifestyle habits. Making the following lifestyle changes now can help you prevent or lower your risk for heart disease and angina.

• If angina is the result of exertion, pace yourself and take breaks as needed. Exercise as directed by your doctor and try to lose weight if you are overweight.
• Because angina is often brought on by heavy meals, avoid large meals and rich foods.
• Eat a healthy diet designed to prevent or reduce high blood pressure, high blood cholestrol and obesity.
• If you've been prescribed medications to lower your cholesterol, be sure to take them as directed.
• If you have high blood pressure, consult with your doctor to learn how to bring it under control. Take your blood pressure medications as directed.
• If you have diabetes, follow your doctor's advice to keep blood sugar levels under control. Take medications as directed.
• If you smoke, ask your doctor to help you quit.
• If angina is the result of stress or emotional factors, try to avoid stressful situations and learn coping mechanisms to handle stress.

It's very likely your doctor will prescribe medication to help you manage your angina.

Nitrates are the most commonly used medications to treat angina and are taken when angina occurs or is expected to occur. Nitrates work by relaxing and widening blood vessels, allowing more blood to flow to the heart. Nitrates may be taken when angina pain begins in order to reduce a current episode. By taking nitrates just before pain is expected to occur, patients can prevent angina episodes from occurring. By using nitrate medications on a regular, long-term basis, patients can reduce the number of angina episodes that occur.¹⁵

Other angina medications include:¹⁶

• Beta blockers which can delay or prevent the onset of angina by slowing heart rate and lowering blood pressure;
• Calcium channel blockers which relax blood vessels so more blood flows to the heart, reducing pain from angina;
• ACE inhibitors which lower blood pressure and reduce the strain on the heart;
• Glycoprotein IIb-IIIa inhibitors and oral antiplatelet medications such as aspirin and clopidigrel which stop platelets (small blood cell fragments) from clumping together to form blood clots; and
• Anticoagulants which prevent clots from forming in your arteries and blocking blood flow.

When treatments and medications are ineffective in controlling angina, special surgical procedures such as angioplasty or coronary artery bypass surgery may be necessary.

Angioplasty
Angioplasty is a procedure to open blocked or narrow coronary arteries, improving blood flow to the heart and relieving chest pain. Angioplasty can also prevent a heart attack. In some cases, a stent is placed inside the artery to keep it open after the procedure.¹⁶

Coronary artery bypass surgery
Coronary artery bypass surgery uses arteries or veins from other parts of the body to bypass blocked coronary arteries. Bypass surgery improves blood flow to the heart, relieves chest pain, and like angioplasty, it can help prevent a heart attack.¹⁷

Following surgery, your doctor may recommend cardiac rehabilitation. Exercise training will help you learn to exercise safely while strengthening muscles and improving daily stamina. Education, counseling and training will help you understand your condition and learn ways to reduce your risk of future heart problems. Working with doctors, nurses, exercise specialists, physical and occupational therapists, dietitians and a psychologist, you will learn not only to cope with the stress of adjusting to a new lifestyle, but also to deal with fears about the future.¹⁸

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1. What is Angina? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
2. What is Angina? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
3. What is Angina? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
4. What Causes Angina? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
5. What Causes Angina? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
6. What Causes Angina? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
7. What Causes Angina? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
8. Who Gets Angina? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
9. Who Are the Common Signs and Symptoms of Angina? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
10. How is Angina Diagnosed? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
11. How is Angina Diagnosed? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
12. How is Angina Diagnosed? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
13. How is Angina Diagnosed? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
14. How is Angina Diagnosed? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
15. How is Angina Treated? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
16. How is Angina Treated? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
17. How is Angina Treated? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.
18. How is Angina Treated? Diseases and Conditions Index. National Heart, Lung, and Blood Institute. US Department of Health & Human Services.