A computed tomography (CT) scan can help diagnose the cause of chest pain faster than standard tests, a new study suggests. The study included 749 people who came to emergency rooms with chest pain. They were given standard tests, including an electrocardiogram and blood tests. But these tests did not show clear signs of a heart attack. Half of the people also were given CT scans. The others were observed in the emergency room and got repeat tests a few hours later. This was followed by an exercise stress test. Stress tests and CT scans both are used to detect artery blockages that can lead to a heart attack. Finding out who had impending heart attacks took an average of three hours using CT scans. It took an average of six hours for the other group. The Associated Press wrote about the study. It was released November 18 at a conference.

By Howard LeWine, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

Emergency department doctors find chest pain one of the more challenging symptoms. Ideally, an electrocardiogram (EKG) is done within minutes of arrival at the hospital. If the EKG shows changes that suggest a heart attack has occurred or is likely to occur soon, then the next actions are well defined.

It would be great if an EKG was a perfect diagnostic test. But some people with a heart attack have a normal EKG. This is where the challenge lies. Only a small percentage of people with chest pain and a normal EKG are at immediate risk of a heart attack. The great majority have some other cause that is not a danger sign.

It would be impractical to keep every adult with chest pain in the hospital to be 100% sure that no heart attacks were missed. To help determine the best course of action, doctors next consider whether the person has any factors that increase the risk of coronary heart disease. Heart disease is unlikely in a man younger than 30 or a woman younger than 40 who is otherwise healthy and has no risk factors.

The important risk factors include:

• A history of chest pain (angina) or prior heart attack
• Diabetes
• Smoking
• A high LDL cholesterol
• A low HDL cholesterol
• High blood pressure
• Family history of heart attack at an early age

A person with chest pain who has a normal EKG and no more than one other risk factor is considered to be at low risk for an impending heart attack.

The next step traditionally is to do a blood test. The laboratory looks for an enzyme called troponin in the blood that detects even a small amount of heart damage. If this test is normal, the person is observed in the emergency department. The EKG and blood troponin tests are repeated about eight hours later. If these tests are again normal, the person then goes for an exercise stress test. This whole process often takes 24 hours.

This week, researchers reported on a faster way to reach a conclusion about who can go home with chest pain. Computed tomography (CT) scans of the heart can detect calcium deposits in the coronary arteries. These deposits indicate a buildup of fatty plaque in the arteries. The presence of fatty plaque means that the person has coronary artery disease.

The researchers divided people at low risk who had chest pain into two groups. One received the traditional evaluation of chest pain with an exercise stress test. The other group received a heart CT scan. Both groups had normal initial EKGs and blood troponin tests.

Both tests were equal in their ability to determine who can go home vs. who needs to stay for more tests. These other tests included specialized dye tests or coronary angiograms. Both tests increase the amount of time spent in the hospital.

Using CT heart scans cut in half the amount of time needed to decide whether or not to send someone home. Costs also were significantly reduced. The CT heart scan strategy saved almost 40% of the usual costs.

What Changes Can I Make Now?

If you have new chest pain, it is always best to have it evaluated right away, or at least call your doctor for advice.

You should always seek emergency care if the chest pain is crushing or squeezing or if you also have any of these symptoms:

• Shortness of breath
• Discomfort or tingling in the arms, especially the left arm
• Pain in the back
• Tightness or pain in the lower jaw
• Profuse sweating
• Lightheadedness or loss of consciousness

But if you don't have any of those symptoms, it does not mean that the chest pain is not a serious symptom. Other causes of chest pain also are potentially life-threatening. A blood clot in the lung (pulmonary embolism) is one example.

Also, not everyone has these "classic" symptoms of coronary heart disease. Women often have less typical symptoms. These may include shortness of breath or feeling extremely weak during physical exertion or emotional stress, even when there is no chest pain.

What Can I Expect Looking to the Future?

Experts have debated the usefulness of heart CT scans as a way to screen for the presence of coronary heart disease. So far, there is no consensus. Repeating CT scans over many years exposes you to a lot of radiation. And there are equally effective methods to determine heart attack risk that are safer.

However, a one-time CT heart scan to help diagnose the cause of chest pain is a very promising advance. More studies are needed to confirm the results found by these researchers.