Chest Pain, Angina Causes

Common symptom which can be caused by many different conditions. Some causes of chest pain require prompt medical attention, such as angina, heart attack, or tearing of the aorta.



Other causes of chest pain can be evaluated electively, such as spasm of the esophagus, gallbladder attack, or inflammation of the chest wall. Therefore, an accurate diagnosis is important in providing proper treatment to patients with chest pain. The diagnosis and treatment of angina is discussed below, as well as the diagnosis of other causes of chest pain that can mimic angina.

Angina


Is the chest discomfort that occurs when the blood oxygen supply to an area of the heart muscle does not meet the demand. In most cases, the lack of blood supply is due to a narrowing of the coronary arteries as a result of arteriosclerosis (see below). Angina is usually felt as a squeezing, pressure, heaviness, tightening, or aching across the chest, particularly behind the breastbone. This pain often radiates to the neck, jaw, arms, back, or even the teeth. Patients may also complain of indigestion, heartburn, weakness, sweating, nausea, cramping, and shortness of breath. Angina usually occurs during exertion, severe emotional stress, or after a heavy meal. During these periods, the heart muscle demands more blood oxygen than the narrowed coronary arteries can deliver. Angina typically lasts from 1 to 15 minutes and is relieved by rest or by placing a nitroglycerin tablet under the tongue. Nitroglycerin relaxes the blood vessels and lowers blood pressure. Both resting and nitroglycerin decrease the heart muscles demand for oxygen, thus relieving angina.

Angina Causes


The most common cause of angina is coronary artery disease. A less common cause of angina is spasm of the coronary arteries. Coronary arteries supply oxygenated blood to the heart muscle.

Coronary artery disease develops as cholesterol is deposited in the artery wall, causing the formation of a hard, thick substance called cholesterol plaque. The accumulation of cholesterol plaque over time causes narrowing of the coronary arteries, a process called arteriosclerosis. Arteriosclerosis can be accelerated by smoking, high blood pressure, elevated cholesterol, and diabetes. When coronary arteries become narrowed by more than 50% to 70%, they can no longer meet the increased blood oxygen demand by the heart muscle during exercise or stress. Lack of oxygen to the heart muscle causes chest pain (angina). For further information on cholesterol, please read the Cholesterol article.

The walls of the arteries are surrounded by muscle fibers. Rapid contraction of these muscle fibers causes a sudden narrowing (spasm) of the arteries. A spasm of the coronary arteries reduces blood to the heart muscle and causes angina. Angina as a result of a coronary artery spasm is called "variant" angina or Prinzmetal angina. Prinzmetal angina typically occurs at rest, usually in the early morning hours. Spasms can occur in normal coronary arteries as well as in those already narrowed by arteriosclerosis.

Why is it important to establish the diagnosis of angina?
Angina is usually a warning sign of the presence of significant coronary artery disease. Patients with angina are at risk of developing a heart attack (myocardial infarction). A heart attack is the death of heart muscle precipitated by the complete blockage of a diseased coronary artery by a blood clot. For further information, please read the Heart Attack article.

During angina, the lack of oxygen (ischemia) to the heart muscle is temporary and reversible. The lack of oxygen to the heart muscle resolves and the chest pain disappears when the patient rests. The muscle damage in a heart attack is permanent. The dead muscle turns into scar tissue with healing. A scarred heart cannot pump blood as efficiently as a normal heart, and can lead to heart failure.

Up to 25% of patients with significant coronary artery disease have no symptoms at all, even though they clearly lack adequate blood and oxygen supply to the heart muscle. These patients have "silent" angina. They have the same risk of heart attack as those with symptoms of angina.

Angina Diagnostic


The resting electrocardiogram (EKG) is a recording of the electrical activity of the heart muscle, and can detect heart muscle which is in need of oxygen. The resting EKG is useful in showing the changes which are caused by a heart attack. It is less useful in patients with angina, since the chest pain and lack of oxygen supply to the heart only become evident during exertion or excitement.

In patients with a normal resting EKG, exercise treadmill or bicycle testing can be useful screening tools for coronary artery disease. During an exercise treadmill test, EKG recordings of the heart are performed continuously as the patient undergoes increasing levels of exercise. The occurrence of chest pain during exercise can be correlated with changes on the EKG which demonstrate the lack of oxygen to the heart muscle. When the patient rests, the angina and the changes on the EKG which indicate lack of oxygen to the heart can both disappear. The accuracy of exercise treadmill tests in the diagnosis of significant coronary artery disease is 60% to 70%.

If the exercise treadmill test does not show signs of coronary artery disease, a nuclear agent (thallium) can be given intravenously during exercise treadmill tests. The addition of thallium allows nuclear imaging of blood flow to different regions of the heart, using an external camera. A reduced blood flow in an area of the heart during exercise, with normal blood flow to the area at rest, signifies significant artery narrowing in that region of the heart.

Stress echocardiography combines echocardiography (ultrasound imaging of the heart muscle) with exercise treadmill testing. Like the exercise thallium test, stress echocardiography is more accurate than an exercise treadmill test in detecting coronary artery disease. When a coronary artery is significantly narrowed, the heart muscle supplied by this artery does not contract as well as the rest of the heart muscle during exercise. Abnormalities in muscle contraction can be detected by echocardiography. Stress echocardiography and thallium stress tests are both about 80% to 85% accurate in detecting significant coronary artery disease.

When a patient cannot undergo exercise stress test because of neurological or arthritic difficulties, medications can be injected intravenously to simulate the stress on the heart normally brought on by exercise. Heart imaging can be performed with a nuclear camera or echocardiography.

Cardiac catheterization with angiography (coronary arteriography) is a technique that allows x-ray pictures to be taken of the coronary arteries. It is the most accurate test to detect coronary artery narrowing. Small hollow plastic tubes (catheters) are advanced under x-ray guidance to the openings of the coronary arteries. Iodine contrast "dye," is then injected into the arteries while an x-ray video is recorded. Coronary arteriography gives the doctor a picture of the location and severity of coronary artery disease. This information can be important in helping doctors select treatment options.

What are other causes of chest pain?
In caring for patients with chest pain, the doctor distinguishes whether the pain is related to a lack of oxygen to the heart muscle (as in angina or heart attack), or is due to another process. Many conditions are considered that can cause chest pain which is similar to that of a heart attack or angina. Examples include the following:
  • Pleuritis - inflammation of the lining of the lung.
  • Pericarditis - inflammation of the lining of the heart.
  • Pulmonary embolism - a blood clot in the lung.
  • Pneumothorax - bursting of the tiny air sacs in the lung tissue.
  • Mitral valve prolapse - a valve abnormality occurring in the heart.
  • Aortic dissection - a tear up the wall of the aorta.
  • Costochondritis - inflammation of the cartilage at the end of the ribs next to the breastbone.
  • Rib fractures.
  • Nerve compression - external pressure on the nerves.
  • Shingles - nerve infection due to the herpes zoster virus.
  • Esophageal spasm and reflux - spasm of the esophagus and regurgitation of the stomach contents and acid into the esophagus.
  • Gallbladder attack (gallstones).
  • Anxiety and panic attack.
Inflammation of the lining of the lungs (pleuritis) causes sharp chest pain, which is aggravated by deep breathing and coughing. This condition is called pleurisy. Patients often notice a shortness of breath, in part due to their shallow breathing to minimize chest pain. Viral infections are the most common causes of pleurisy. Other systemic inflammatory conditions, such as systemic lupus, can also cause pleurisy.

Inflammation of the lining around the heart is called pericarditis. Symptoms of pericarditis are similar to that of pleuritis. Please read the Pericarditis article.

A bacterial infection of the lung (pneumonia) causes fever and chest pain. Bacterial pneumonia is due to an irritation or infection of the lining of the lung (pleura). Please read the Pneumonia article.

When blood clots travel from the veins of the pelvis or the lower extremities to the lung, the condition is called pulmonary embolism. Pulmonary embolism can cause death of lung tissue (pulmonary infarction). Pulmonary infarction can lead to irritation of the pleura, causing chest pain similar to pleurisy. Some common causes of blood clots in these veins include prolonged immobility, recent surgery, trauma to the legs, or pelvic infection.

The small sacs in the lung tissue can spontaneously burst, causing pneumothorax. Symptoms of pneumothorax include sudden, severe, sharp chest pain and shortness of breath. One common cause of pneumothorax is severe emphysema.

Mitral valve prolapse (MVP) can cause chest pain. Mitral valve prolapse is a common heart valve abnormality, affecting 5- 10% of the population. MVP is especially common among women between 20 to 40 years of age. Chest pain with MVP is usually sharp and can be prolonged. Unlike angina, chest pain with MVP rarely occurs during or after exercise, and may not respond to nitroglycerin. For further reading, please read the Mitral Valve Prolapse (MVP) article.

The aorta is the major vessel delivering blood from the left ventricle to the rest of the body. Tearing of the aorta wall (aortic dissection) is a life-threatening emergency. Aortic dissection causes severe, unrelenting chest and back pain. Young adults with aortic dissection usually have Marfan's syndrome. Marfan's syndrome is an inherited disease in which an abnormal form of the structural protein called collagen causes weakness of the aortic wall. Older patients develop aortic dissection typically as a result of chronic, high blood pressure, in addition to generalized hardening of the arteries (arteriosclerosis).

Pain originating from the chest wall may be due to muscle strain or spasm, costochondritis, or rib fractures. Chest wall pain is usually sharp and constant. It is usually worsened by movement, coughing, deep breathing, and direct pressure on the area. Muscle spasm and strain can result from vigorous, unusual twisting and bending. The joints between the ribs and cartilage next to the breastbone can become inflamed, a condition called costochondritis. Fractured ribs resulting from trauma or cancer involvement can cause significant chest pain. Common cancers that spread (metastasize) to the ribs include breast and prostate cancer.

Compression of the nerve roots by bone spurs as they exit the spinal cord can cause pain. Nerve compression can also cause weakness and numbness in the upper arm and chest. Nerve irritation also occurs with shingles (herpes zoster infection of the nerves), which can cause chest pain days before any typical rash appears.

The esophagus is the long muscular tube connecting the mouth to the stomach. Reflux, or regurgitation of stomach contents and acid into the esophagus can cause heart burn and chest pain. For further information, please read the Gastroesophageal Reflux Disease (GERD) article. Spasm of the muscle of the esophagus can also cause chest pain which can be indistinguishable from chest pain caused by angina or a heart attack. The cause of esophageal muscle spasm is not known. Pain of esophageal spasm can respond to nitroglycerin in a similar manner as angina.

Gallstones can cause severe pain of the upper abdomen, back and chest. Gallbladder attacks can mimic the pain of angina and heart attack. For further information, please read the Gallstones article.

Anxiety, depression, and panic attacks are frequently associated with chest pain lasting from minutes to days. The pain can be sharp or dull. It is usually accompanied by shortness of breath, or the inability to take a deep breath. Emotional stress can aggravate chest pain, but the pain is generally not related to exertion, and is not relieved by nitroglycerin. These patients often breath too fast (hyperventilate), causing light-headedness and numbness and tingling in the lips and fingers. Coronary artery disease risk factors are typically absent in these patients. Since there is no test for panic attacks, patients with chest pain usually undergo tests to exclude coronary artery disease and other causes of chest pain.

Patients with chest pain - Diagnostic


The first step in the diagnosis of chest pain is the doctor's physical examination of the patient. In patients with costochondritis and rib fracture, the affected areas are tender to external pressure. In patients with herpes zoster, the characteristic rash of shingles usually appears 1 to 3 days after the onset of the sharp, burning chest pain.

The doctor listening to the lungs with a stethoscope can detect a scratchy, rubbing sound during breathing, suggesting pleurisy. A similar rubbing sound heard over the heart during heart beating can indicate pericarditis. The heart might have an extra clicking sound during heart contraction in patients with mitral valve prolapse. Decreased and abnormal sounds heard over the chest suggest pneumonia. The lack of breathing sounds or severe shortness of breath in a patient with a rib fracture can be a sign of a puncture of the lung, leading to pneumothorax. The finding of a swollen thigh or calf after surgery in a patient with shortness of breath and chest pain suggests blood clots in the leg and pulmonary embolism.

Many radiological techniques are available to the doctor in evaluating patients with chest pain. Chest x-rays are useful in detecting pneumonia, pneumothorax, rib fractures, and sometimes fluid along the lung lining due to pleurisy. Echocardiography uses ultrasound waves to make pictures of the heart and can help detect inflammation of the heart lining. It is also useful in detecting mitral valve prolapse. Ultrasound examination of the gallbladder is highly accurate for gallstones. X-ray motion pictures can be obtained of the esophagus after swallowing a chalky substance (barium) to detect spasm and other abnormalities of the esophagus.

In patients suspected of having a pulmonary embolism, an ultrasound study and other x-rays can be obtained to detect clots in the veins of the lower extremities. To identify blood clots in the lungs, nuclear isotopes are administered intravenously as well as by inhalation. Nuclear cameras are then used to detect uneven distribution of these nuclear isotopes in the lungs, indicating the presence of blood clots. Pulmonary angiography is sometimes needed to confirm the diagnosis of pulmonary emboli. During pulmonary angiography, contrast dye is injected through a small hollow plastic tube (catheter) into the pulmonary arteries while x- rays are taken.

The electrocardiogram (EKG) is a recording of the electrical activity of the heart. It is useful in showing the typical changes of pericarditis in up to 90% of patients.

Tearing (dissection) of the aorta usually is seen as a large aortic shadow on the chest x-ray. This diagnosis can be confirmed by a computed tomographic (CT) x-ray or magnetic resonance imaging (MRI). Angiography, a procedure which involves using contrast dye injected into the aorta, has been considered the most accurate test for aortic dissection. A newer technique called transesophageal echocardiography (TEE) appears to be as accurate as angiography in detecting aortic dissection. A small ultrasound probe is advanced into the mouth and down the esophagus while pictures are taken of the adjacent aorta.

Treatment options for Angina


Treatment options include rest, medications (nitroglycerin, beta-blockers, calcium channel blockers), percutaneous transluminal coronary angioplasty (PTCA), or coronary artery bypass graft surgery (CABG).

Resting, sublingual (placed under the tongue) nitroglycerin tablets, and nitroglycerin sprays all relieve angina by reducing the heart muscle's demand for oxygen. Nitroglycerin also relieves spasm of the coronary arteries and can redistribute coronary artery blood flow to areas that need it most. Short- acting nitroglycerin can be repeated at 5 minute intervals. When 3 doses of nitroglycerin fail to relieve the angina, further medical attention is recommended. Short-acting nitroglycerin can also be used prior to exertion to prevent angina.

Longer-acting nitroglycerin preparations, such as Isordil tablets, Nitro-Dur transdermal systems (patch form), and Nitrol ointment are useful in preventing and reducing the frequency and intensity of episodes in patients with chronic angina. The use of nitroglycerin preparations can be limited by headaches and light-headedness due to an excess lowering of blood pressure.

Beta blockers relieve angina by inhibiting the effect of adrenaline on the heart. Inhibiting adrenaline decreases the heart rate, lowers the blood pressure, and reduces the pumping force of the heart muscle, all of which reduce the heart muscle's demand for oxygen. Examples of beta blockers include propranolol (Inderal), metoprolol (Lopressor), and atenolol (Tenormin). Side effects include worsening of asthma, excess lowering of the heart rate and blood pressure, depression, fatigue, impotence, increased cholesterol levels, and shortness of breath due to diminished heart muscle function (congestive heart failure).

Calcium channel blockers relieve angina by lowering blood pressure, and reducing the pumping force of the heart muscle, thereby reducing muscle oxygen demand. Calcium channel blockers also relieve coronary artery spasm. Examples of calcium channel blockers include nifedipine (Procardia), verapamil (Calan), and diltiazem (Cardizem). Verapamil and diltiazem also lower the heart rate. Side effects include swelling of the legs, excess lowering of the heart rate and blood pressure, and depressing heart muscle function, thereby causing an increased shortness of breath.

A recent study found that patients with high blood pressure taking short-acting calcium blockers (Procardia, Cardizem, and Calan) had a higher rate of heart attacks. This has not been shown for the longer acting preparations (Procardia-XL, Cardizem-CD, and Calan-SR) and has not been confirmed by other long-term studies. Until other studies are available, no conclusive statements can be made about the safety of these agents. Patients are urged to consult with their doctors before changing any of their angina medications.

When patients continue to have angina despite maximally tolerated combinations of nitroglycerin medications, beta-blockers and calcium-blockers, cardiac catheterization with coronary arteriography is indicated. Depending on the location and severity of the disease in the coronary arteries, patients can be referred for balloon angioplasty (percutaneous transluminal coronary angioplasty or PTCA) or coronary artery bypass graft surgery (CABG) to increase coronary artery blood flow. Please read the Balloon Angioplasty and Coronary Artery Bypass Graft (CABG) articles.

What's new in the evaluation of angina?
A newly developed computerized x-ray scan (ultrafast CT scan) is highly accurate in detecting small amounts of calcium in the plaque of coronary arteries. If an ultrafast CT scan shows no calcium in the arteries, atherosclerotic coronary artery disease is unlikely. Therefore, ultrafast CT scanning is useful in evaluating chest pain in younger patients (men under 40 and women under 50 years old). Since young people do not normally have significant coronary artery plaque, a negative ultrafast CT scan makes the diagnosis of coronary artery disease unlikely. However, finding calcium by this method is less meaningful in older patients who are likely to have mild plaquing simply from the aging process.

Even though an ultrafast CT scan is useful in detecting calcium in plaque, it cannot determine whether the calcium-laden plaque actually causes artery narrowing and reduces blood flow. For example, a patient with a densely calcified plaque causing minimal or no artery narrowing will have a strongly positive ultrafast CT scan but a normal exercise treadmill test. In most patients who are suspected of having angina due to coronary artery disease, an exercise treadmill study is usually the first step in determining whether any plaque is clinically significant.

Magnetic resonance imaging (MRI), using magnetism and radio waves, can be used to image (produce a likeness of) the blood vessels. Currently, the larger vessels, such as the carotid arteries in the neck, can be imaged using this technique. Over the next 5 to 10 years, software and hardware improvements may allow screening of the heart's arteries with magnetic resonance testing.

What's new in the treatment of angina and heart attacks?
Coronary arteries can close after angioplasty, causing recurrent angina or even heart attacks. One way to decrease the risk of coroany artery closure is by deploying stents to keep the arteries open. Newer drug coated stents are being developed to significantly reduce the rate of artery closure.

Angina At A Glance
  • Angina is one of many causes of chest pain.
  • Angina is chest pain that is a result of inadequate oxygen supply to the heart muscle.
  • Angina can be caused by coronary artery disease or spasm of the coronary arteries.
  • EKG, exercise treadmill, stress echocardiography, stress thallium, and cardiac catheterization are important in the diagnosis of angina.
  • Treatment of angina includes rest, medications, angioplasty, and/or coronary artery bypass surgery.