Angina (angina pectoris) is a type of temporary chest pain, pressure or discomfort. It is often described as a crushing, burning, heavy sensation, and it frequently radiates from the chest into other parts of the body, such as the neck, back, arms, jaw and abdomen. In women, angina may be experienced as abdominal pain. Typical episodes of angina can last anywhere from two to 15 minutes.
About 9.1 million Americans suffer from angina, according to the American Heart Association. In the United States, angina afflicts an estimated 3.9 percent of white women, 4.3 percent of black women, 3.3 percent of Mexican-American women, 4.8 percent of white men, 3.4 percent of black men and 2.3 percent of Mexican-American men.
Angina occurs when the heart is temporarily deprived of oxygen, a condition called cardiac ischemia. The most common cause of cardiac ischemia is coronary artery disease, a condition in which oxygen-rich blood cannot travel freely through coronary arteries that are severely hardened and narrowed (atherosclerotic) from plaque buildup and calcification.
If the angina occurs at predictable times, usually after exercise or exertion, it is called stable angina. If the angina occurs at unpredictable times, including at rest, and lasts longer than typical angina episodes, it is known as unstable angina. Unstable angina may signal an impending heart attack. People experiencing unstable angina should seek medical attention immediately.
Besides coronary artery disease, other causes of cardiac ischemia and angina include problems with:
- The heart’s aortic valve, such as regurgitation (leaking) or stenosis (narrowing).
- The heart muscle, as in hypertrophic subaortic stenosis (also known as hypertrophic cardiomyopathy).
- The capillaries, which could lead to a diagnosis of microvascular angina or cardiac syndrome X.
- Coronary artery spasms, which could lead to a diagnosis of variant or Prinzmetal angina. This type of angina is rare, and may be considered a form of unstable angina. It almost always occurs when patients are at rest, typically between midnight and early morning. It is common for these patients to have “active” periods of variant angina, with frequent anginal episodes over a period of months. Two-thirds of people with variant angina have severe blockage in at least one major vessel. There is also a greater risk of developing abnormal heart rhythms (arrhythmias), such as ventricular tachycardia and ventricular fibrillation.
Cardiac ischemia can also lead to dangerous problems if underlying conditions are left untreated:
- Arrhythmias, which can lead to either syncope (fainting) or sudden cardiac death.
- Heart disease patients whose episodes are triggered by stress (e.g., frustration, hostility) are more likely to die from their heart condition.
- Severe or lengthy episodes can trigger a heart attack.
- The small effects of minor episodes can eventually lead to permanent weakening of the heart muscle (cardiomyopathy).
There are two main types of angina pectoris. Stable (classical) angina is much more common. About 500,000 new cases of stable angina are reported annually in the United States, according to the American Heart Association.
Stable angina occurs while (or just after) the heart has a need for extra oxygen. The heart needs extra oxygen during a variety of situations that put extra stress on the heart, which include:
- Cigarette smoking
- Eating and digesting a heavy meal
- Physical exertion, especially after eating
- Strong emotions, such as anger or frustration – even during a dream
- Sudden changes in temperature or altitude
Stable angina attacks typically last anywhere from one to 15 minutes, with relief brought on by rest and/or medication. The pain or discomfort associated with episodes of stable angina typically reflects a temporary reduction in blood flow to the heart muscle, rather than permanent damage to the heart muscle.
Chest pain or discomfort that occurs at unpredictable times, including at rest, and does not resolve within 15 minutes (with or without medication) may be a sign of unstable angina. Another indication of unstable angina is an increase in frequency and/or severity of stable angina. Unstable angina is a dangerous medical condition that may signal the progression of underlying coronary artery disease. In some cases, unstable angina will be provoked after a plaque ruptures within the coronary arteries. This causes the artery to narrow, further restricting blood flow to the heart. Unstable angina may also be caused by blood clots that form on damaged plaque.
Episodes of unstable angina can occur at low levels of exertion, even when a person is at rest, and in individuals having no prior history of angina. Indeed, sudden and unrelieved chest pain may cause people to suspect they are having heart attack. Physicians therefore use caution and approach the situation as an emergency. This is because unstable angina can quickly develop to a heart attack, and cardiac enzyme levels may not indicate any heart muscle damage -- or healing -- until days after a heart attack. There is also an increased risk for life-threatening arrhythmias (e.g., ventricular tachycardia and ventricular fibrillation).
It should be noted that some people have episodes of cardiac ischemia that produce no type of angina at all. These episodes are called silent ischemia. This type of cardiac ischemia is usually diagnosed from an exercise stress test. Studies have demonstrated that silent ischemia can be more common among certain ethnic or racial groups. For example, recent reports find that Asian Americans, in comparison to white Americans, experience significantly fewer episodes of ischemic chest pain. Other symptoms, however, occur more frequently, such as shortness of breath, fatigue and palpitations.
The most common symptom that people report when they have angina is chest pain, pressure or a vague chest discomfort. In fact, the term angina pectoris means "a choking sensation of the chest."
An angina attack may feel like a squeezing vise or crushing pressure deep in the chest behind the breastbone (sternum), and may radiate into the back, neck, jaw, shoulders, arms and even fingers or abdomen. People experiencing angina may also feel light-headed and have an abnormally fast or abnormal heartbeat (arrhythmia). Some people, especially women and individuals with diabetes, may have atypical, nonspecific or vague symptoms.
The pain is not necessarily severe. People experiencing angina often assume it is due to noncardiac causes such as indigestion, heartburn or costochondritis (an inflammation of cartilage in the ribcage).
From the patient’s description of symptoms, a physician can usually determine whether angina is present during a physical examination. Words used to describe angina include tightness, squeezing, crushing, burning, choking or aching. Because angina is not specific in location, patients may not be able to tell exactly where it comes from. Instead, they may make a fist in the middle of their chest to demonstrate chest pain. This is called a Levine sign and may cause the physician to suspect angina.
During an angina attack, a physician will assess a patient’s heartbeat, heart rate and blood pressure, which can be elevated. Various blood tests and/or a urine test may be ordered. From there, additional tests may be performed to determine the underlying cause of the angina, as well as the extent of any heart damage and coronary artery disease. These include:
An electrocardiogram (EKG) is performed while the patient exercises in a controlled manner on a treadmill or stationary bicycle at varied speeds and elevations. The reaction of the heart under exertion can be measured and evaluated. However, the EKG reading may be normal, even for a patient with extensive damage to the heart.
A nuclear imaging test is a test in which the patient is injected with a radionuclide substance, such as thallium, to produce contrasts (pictures) of the heart. Nuclear tests allow physicians to measure the uptake of blood or nutrients into the heart muscle, which provides a good picture of healthy versus unhealthy heart tissue. Nuclear imagng can be performed in conjunction with exercise as a nuclear stress test.
A common type of stress test that combines EKG and echocardiogram to evaluate cardiac ischemia. While the patient is either exercising or has been given a medication that causes the heart to react as if the person were exercising the reaction of the heart under stress can be measured.
During this test, a special dye is delivered through a thin tube to the coronary arteries. This dye appears on an x-ray (radiopaque) and helps physicians pinpoint the location and severity of blockages in the coronary arteries.
This uses multiple x-ray sensors, or an electron beam, to provide very detailed, three-dimensional images of the heart. This technique allows physicians to obtain very detailed images of the heart while it works. Both multi-sensor computed tomography, which can yield up to 64 angles during a single scan, and rapid electron beam computed tomography, which takes a scan during a single heartbeat, are also used to measure the degree of calcification in the coronary arteries. These tests are useful for people with established heart disease because the degree of calcification is related to heart-attack risk. However, people who have a very low risk of heart attack are not advised to undergo calcium scoring using computed tomography, and people who are at high risk should already be under intensive treatment and therefore are not advised to undergo calcium scoring.
The course of treatment for angina will depend on the physician's determination of its severity and the extent of underlying cardiovascular damage. The patient's family medical history, particularly for heart disease, will also play a role in planning treatment.
For most patients with mild, stable angina, a combination of medications and risk-reducing lifestyle changes is usually recommended.
- Eating a heart-healthy diet
- Improving cholesterol ratio
- Exercising regularly
- Controlling diabetes
- Controlling high blood pressure (hypertension)
- Achieving and maintaining a healthy weight
- Managing stress
- Quitting smoking (or not starting to smoke)
- Controlling depression and emotional factors
Medications used to treat angina either increase the supply of oxygen to the heart muscle or reduce the heart's need for oxygen.
- Nitrates (e.g., nitroglycerin) widen, or dilate, the walls of the blood vessels. These drugs allow more blood, and therefore oxygen, to reach the heart, thus lessening the pain associated with angina attacks. Nitrates can be taken during an angina attack and may rapidly provide relief of symptoms, or they can be administered as daily medications for long-term control. In cases of persistent anginal episodes, nitroglycerin can be added to other medications, such as beta blockers or calcium channel blockers.
- Beta blockers slow the heart's resting rate and reduce the force of the accompanying heart muscle contraction, thus lessening the heart’s workload.
- Calcium channel blockers (calcium antagonists) block the entry of calcium into the cells, thus reducing the amount of calcium. This widens (dilates) the coronary arteries and increases the heart's blood flow. This class of drugs can also be used to treat coronary artery spasms associated with variant or Prinzmetal angina.
- Antiplatelet medications inhibit the formation of blood clots by decreasing the ability of platelets (the body's natural blood-clotters) to bind together and form blood clots. These drugs are typically not prescribed to reduce angina, but to reduce the risk of heart attack associated with coronary artery disease, of which angina is a major symptom. Aspirin is the most common antiplatelet. A second novel therapy is the combination of aspirin and another antiplatelet, clopidogrel (Plavix). Recent data suggest that these two drugs produce an enhanced, additive effect in reducing the risk of embolism and other adverse events after an episode of unstable angina. Positive results are also being seen with combined aspirin and clopidogrel in coronary stenting.
- Anticoagulant medications inhibit the formation of blood clots by inhibiting any of a number of coagulation factors. These drugs are typically administered to people who are at high risk of blood clots causing a heart attack or stroke. Anticoagulants, commonly called "blood thinners," must be closely monitored to make sure there is not increased risk of bleeding.
Individuals are encouraged to discuss with their physician any other medications or supplements they may be taking. For example, if a patient takes medication for erectile dysfunction in combination with nitrates it can provoke a dangerous drop in blood pressure.
In 2006 the U.S. Food and Drug Administration approved ranolazine (Ranexa), a treatment for chronic angina. Studies have shown that ranolazine is effective among patients with stable angina, but because it alters the heart rhythm, as a treatment for angina it is generally recommended only for patients who have failed other therapies.
For most patients with more serious or worsening angina, especially those in whom significant damage has already been found, further procedures may be performed, including:
Angioplasty is a procedure in which a balloon–tipped catheter is inserted into a partially blocked coronary artery and rapidly inflated. The balloon compresses the plaque, pushing it against the artery wall, to allow for freer blood flow. Angioplasty is often followed by the insertion of a stent.
Stenting is a procedure in which a small wire mesh tube called a stent is placed into a damaged artery via a catheter, usually at the same time an angioplasty is performed, to support and stretch the artery walls and provide for unrestricted blood flow. The development of drug-coated (drug-eluting) stents has helped to reduce the rates of re-narrowing (restenosis) after stenting and angioplasty. However, some recent data have implicated drug-eluting stents with increased long-term risk of blood clots, and researchers are studying the best application of stents.
Atherectomy is a procedure in which a special catheter equipped with a grinding burr or blade is used to cut away plaque in the arteries. The plaque is then removed when the catheter is withdrawn from the artery, or the tiny pieces are absorbed into the bloodstream. This procedure is generally reserved for a small subset of patients because of the higher risks associated with the techniques.
Coronary artery bypass grafting (CABG) is major surgery that relies on grafts created from the patient's own veins and arteries from elsewhere in the body (such as the internal mammary artery in the chest) to reroute the flow of blood around a blocked area of a coronary artery. Coronary artery bypass surgery may be performed with or without the heart-lung machine. If it is performed without the heart-lung machine, it is known as off-pump coronary artery bypass (OPCAB).
Minimally invasive direct coronary artery bypass (e.g., MIDCAB) is a newer, less invasive form of coronary artery bypass surgery. In this procedure, the physician operates through smaller, keyhole incisions in the patient's side. It may be performed with or without use of the heart–lung machine. Because of the limited operating field, it is usually reserved for patients with more limited coronary artery disease and is often performed in conjunction with angioplasty.
Transmyocardial revascularization (TMR), also known as transmyocardial laser revascularization (TMLR), is a newer surgical procedure in which a laser beam is used to make small holes in the heart to improve oxygenation to the heart muscle. This results in less chest pain.
TMR may be an option for patients with severe angina that does not respond to medication. Earlier recommendations also reserved TMR for those not candidates for CABG or angioplasty. However, recent studies have shown benefit with CABG plus TMR, and even TMR with off-pump coronary artery bypass. When performed with bypass surgery, TMR may speed postoperative recovery and improve survival. TMR is not recommended for those with a low ejection fraction or heart failure.
A variation of TMR is called percutaneous myocardial revascularization (PMR), in which the laser is delivered through an artery via a catheter until it is arrives at the heart. Also known as percutaneous transmyocardial laser revascularization (PTMR), this procedure has shown to improve exercise tolerance and relief from angina pain. However, the medical community has only limited experience with this method.
External counterpulsation (ECP or EECP) is a newer, noninvasive technique that may be considered for individuals having stable angina but not eligible for conventional revascularization techniques. EECP uses blood pressure cuffs wrapped around the legs. As they are inflated and deflated, blood is pushed into the heart, improving circulation and reducing the heart's workload. Though this technique does appear to give some patients clinical improvement, it has a limited application and has not been generally accepted
After surgery, medications such as anti-clotting agents and/or antioxidants (both vitamins and drugs) may help to prevent re-blockage of the arteries (restenosis).
Physicians continue to debate whether medication or surgery is preferred for stable angina. In 2007 a major trial called the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) showed that drug therapy lowered patients' risk of heart attack and death. However, some physicians found that the data supported angioplasty as a first-line treatment. Angina may be treated case by case rather than according to one specific protocol because of the wide range of factors such as the patient's overall health, lifestyle and degree of atherosclerosis.
In addition to making healthy lifestyle changes, receiving regular medical care and taking all medication as prescribed, patients are encouraged to become familiar with their family's health histories. Although genetic factors such as disease history, ethnicity and gender cannot be changed, knowing them can help in measuring risk and creating an appropriate plan for making lifestyle changes.
Finally, any marked changes in symptoms, such as having more attacks or having more painful attacks, may be a sign of worsening health and increased risk of heart attack. These changes should be brought to the attention of a physician as soon as possible.
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to angina:
- How do I know if my chest pain is related to a serious condition?
- What type of tests can help determine the cause of my chest pain?
- What do you suspect is the cause of my angina?
- What lifestyle changes can reduce my angina?
- What are my treatment options?
- What are the benefits and risks of these treatments?
- Once I start treatment, when can I expect to see improvement?
- If I have stable angina, am I at greater risk for unstable angina?
- When does angina indicate a medical emergency?
- How does my family medical history affect my risk with angina?
- What can I do to prevent angina?
- If I have angina, are my children at greater risk for the condition?
- You have symptoms of angina pectoris.
- The following occur after diagnosis:
- An attack of chest pain continues longer than 10 to 15 minutes, despite rest and treatment with nitroglycerin.
- You wake from sleep with chest pain that does not go away with 1 nitroglycerin tablet. If these attacks continue, report them, even if nitroglycerin relieves them.
- An attack occurs and the pain is different or more severe than usual.