If you’re simply feeling stressed, that’s not a reason for a stress test.

But if you’re having chest pain or tightness, shortness of breath or other potential warning signs of a heart attack or angina, talk to your doctor. These could be signs that an exercise stress test, stress echocardiography, known as a stress echo, or a stress perfusion study can help your doctor uncover a potential health condition.

The three stress tests

• Exercise test: Measures the effect of exercise on your heart.
• Stress echocardiography: Ultrasound imaging that shows how well your heart muscle is working to pump blood through your body.
• Stress perfusion study: A nuclear tracer element is used to evaluate blood flow into the heart.

Stress test limitations

These tests are the workhorses of heart screening, but they have their limitations.

“A stress test cannot find any blockages in the arteries smaller than 70 percent,” said Dr. Ravi Mareedu, a Marshfield Clinic interventional cardiologist. “Any plaque buildup in the arteries can rupture, even if the narrowing is less than 70 percent, but these tests cannot predict which of the plaques are most vulnerable.”

Stress tests go back decades and are very helpful in finding out if a patient’s symptoms are coming from coronary arteries with severe blockages, greater than 70 percent. While generally accurate, stress tests can sometimes be misleading.

They can give a result that ends up being a false positive, needlessly worrying a patient about coronary artery disease. On the other hand, they can deliver a false negative, giving the patient a false sense of security.

Next step: Angiography

After a stress test indicates an abnormality, heart specialists turn to a more invasive but also much more informative test, a heart catheterization with angiography.

A long, thin tube called a catheter is threaded through blood vessels to the heart. Using a special dye, doctors can see the blockages precisely. People who are in the midst of having a heart attack will often have one or more arteries with major or even complete blockages.

“The take-away message is that doing the right thing for the right patient at the right time is very important,” Mareedu said. “If we err, it’s usually on the side of ordering tests that might be inconclusive. The last thing we want to do is overlook a result just because we think it is a false positive and then have the patient have a heart attack two months later.”

Many people can make lifestyle changes to reduce the need for most, if not all, of these tests.

“There’s no substitute for healthy living. That’s the single most important thing,” Mareedu emphasized. “Eat a well-balanced diet, exercise regularly, quit smoking and drink alcohol in moderation.”