Chest Pain: When is Stress Testing Necessary?

What causes chest pain?

Chest pain can be a symptom of many conditions, some harmless, some life threatening. Doctors often refer to chest pain as being the result of a cardiac or non-cardiac condition. Cardiac chest pain can be further divided into ischemic and non-ischemic pain.

Ischemic chest pain, or angina, is typically the result of impaired blood flow to an area of heart muscle resulting from a blockage in a coronary artery. This is known as coronary artery disease (CAD). When this happens, the area of heart muscle downstream from the blockage does not receive adequate oxygen and nutrients to function normally, causing nerve endings in the area to signal the brain of the problem. A person perceives this signal as chest pain or discomfort, often described as tightness, squeezing, burning, aching, pressure, heaviness, heartburn or indigestion, and stabbing sensations. Angina is typically located in the chest, but its affects can be felt in the arms, back, neck, or throat. Other symptoms that might accompany angina include shortness of breath, sweating, nausea, vomiting, palpitations, dizziness, and weakness. This sensation typically gets worse with exertion or emotional stress, and improves with rest or prescribed nitroglycerin.

Sources of non-ischemic, cardiac chest pain include pericarditis, aortic aneurysm, mitral valve prolapse, or arrhythmias.

Pericarditis refers to inflammation of the thin sac that surrounds the heart. This is most commonly the result of an infectious or autoimmune process. The sensation is typically a very severe, sharp, localized chest pain that is made worse by laying back, deep breathing, or coughing. Sitting up and leaning forward often relieve the pain.

The presence of an aortic aneurysm is usually not a source of any discomfort for a patient. The aneurysm is an abnormally dilated (widened) section of the aorta where the wall of the aorta can be weakened. This area can rupture suddenly, leak slowly, or the innermost layer of the aorta can tear, allowing blood to enter between the layers of the wall of the aorta (aortic dissection).

Pressure associated with the pulse-like flow of blood causes the layers to separate further causing the aneurysm to rupture. A ruptured aneurysm is rare but is catastrophic when it occurs. It results in a sudden drop in blood pressure and frequently sudden death unless the rupture results only in a slow leak of blood from the aorta. A leaking aneurysm or aortic dissection often results in a sudden, severe, tearing chest pain that is usually felt between the shoulder blades, abdomen, or flank (side).

Mitral valve prolapse, caused by a drooping or bulging of the heart's mitral valve, does not usually cause any symptoms. However, it can be associated with chest pain syndromes that are not typical of ischemic cardiac chest pain. The pain can be sharp and stabbing, and persist for long periods of time. It usually does not become worse with activity. No definite cause of the pain has been identified.

Abnormal rapid heart rhythms, called arrhythmias, can also result in a chest discomfort that is usually described as a pressure, heaviness, or pounding. This can occur in the absence of blockages in the coronary arteries and is usually caused by the sensation of the heart beating very rapidly at rest.

Non-cardiac chest pain can result from many conditions, including pneumonia, pleurisy (an inflammation of the membrane that surrounds the lungs), muscle strains in the chest wall, inflammation of the cartilage that attaches the ribs to the breastbone or from the gastrointestinal tract. Gastrointestinal sources of chest discomfort include ulcers of the stomach or esophagus, reflux of acid from the stomach to the esophagus - called gastroesophageal reflux disease (GERD) - or a spasm of the esophagus. Occasionally, pain from the gallbladder can be perceived as chest pain. Finally, anxiety and panic attacks can produce chest pain that resembles ischemic cardiac chest pain.

How do doctors determine if chest pain is from your heart?

A careful medical history and physical examination by your doctor are the first and most important parts of an evaluation. Your doctor might ask you questions about your symptoms including:

• What does it feel like?
• Where is it located?
• Does it stay in one spot or does it radiate to another spot?
• When do you notice it? What brings it on?
• Is it associated with exertion, meals, or certain body positions?
• How long does it last?
• How severe is it?
• When was the last episode?
• Have you found anything that makes it feel better?
• Have you found anything that makes it feel worse?
• Can you reproduce it by pushing on your chest wall?

An EKG and chest X-ray are very important diagnostic tests that your doctor might perform, although normal results do not rule out coronary artery disease.

Based on your history, examination, ECG, and chest X-ray, your doctor will be able to determine the likelihood that your chest pain is related to your heart. If your doctor decides that it is necessary, a stress test might be scheduled to help more definitively determine if coronary artery disease is present. Occasionally, your doctor might recommend a cardiac catheterization to visualize the coronary arteries if the likelihood of CAD seems very high.

What is a stress test?

A stress test is usually ordered to help determine your likelihood of having coronary artery disease (CAD). Stress tests can also be used to determine the effectiveness of your cardiac treatment plan. All stress tests involve either exercising on a treadmill or bike, or using a medicine to produce an effect similar to exercise. You are closely monitored during any type of stress test with continuous EKG monitoring and frequent blood pressure checks. A doctor is always present or immediately available during a stress test.

What are the different types of exercise stress tests?

The most common type of stress test is a simple exercise EKG where you exercise on a treadmill with continuous EKG monitoring and frequent blood pressure monitoring. This is good for patients with a normal resting EKG. Your doctor might order a stress test that utilizes imaging methods to increase the accuracy of the regular exercise EKG. The two imaging methods used include echocardiography and nuclear imaging.

Echocardiography allows visualization of the walls of your heart while nuclear imaging shows the relative blood flow to the different walls of your heart. With both types of stress test, a set of images is obtained at rest and another set after exercise. With stress echocardiography, if you have a significant blockage in a coronary artery, the wall that is supplied by that artery will not be contracting on the ultrasound images obtained immediately after exercise. With a stress test using nuclear imaging, an abnormality is detected when an area of heart muscle appears to have less blood flow compared to the rest of the heart at exercise and compared to the same area of heart muscle at rest.

An exercise stress test provides your doctor with much more information about your likelihood of having CAD than a non-exercise stress test. For this reason, it is always best to exercise if you can. For those who cannot exercise, however, there are medicines used to mimic exercise. The most common ones are dobutamine, persantine, and adenosine.

Dobutamine is most commonly combined with echocardiography while persantine and adenosine are usually combined with nuclear imaging. Dobutamine mimics exercise by increasing your heart rate and blood pressure, thereby increasing the amount of work your heart is doing. Persantine and adenosine both cause your coronary arteries to dilate and increase the blood flow to your heart muscle. If you have a severe blockage in an artery, that artery will not dilate and therefore receive less blood flow compared to an unblocked artery.

Do's and Don'ts about stress tests.

• Don't eat for about six hours before a stress test.
• Don't drink caffeine in the 24-hour period before a persantine or adenosine stress test.
• Do talk to your doctor about which medicines you should take before the test, particularly if you have high blood pressure or diabetes. (In general, you should not take any beta-blocker medicines in the 24-hour period before an exercise stress test and not take any long-acting nitroglycerin or theophylline preparations in the 24-hour period before a persantine or adenosine stress test.)
• Don't stop any medicines without speaking to your doctor first.
• Do wear comfortable clothes and shoes if you are having an exercise stress test.
• Do bring your inhalers if you use them for your breathing.

Notes:

[Watch page ]

EditText of this page (last edited December 19, 2009)