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It’s designed to help doctors evaluate the strength and structure of the heart muscle. But patients may be surprised when they go in for a cardiac stress test and expect to step on a treadmill but instead, doctors sit them down for an injection.

Knowing which test is best for you is critical.

Northshore University HealthSystem cardiologist Dr David Najman explained the process of a typical exercise stress test.

“Every patient that gets a stress test gets hooked up to an EKG machine,” he said.

Step one is to get electrodes on the chest.

“The main reason is to look for blockages to see if people are at risk for heart attack,” Najman said.

Step two is to step on the treadmill.

But there’s an alternative to this type of test with what’s called a chemical or pharmacological stress test.

Doctors have two drug options. Both are delivered through an IV. One medication makes the heart beat faster and stronger to simulate exercise. The other is called a vasodilator – it expands normal arteries. When there’s a blockage, doctors can see the narrowing on imaging, all while the patient is at rest in the lab.

“Some institutions probably do more chemical or pharmaceutical stresses than they should because it is easier and you get patients quicker in and out of the lab,” Najman said.

But ot so fast, says Najman. Make sure you get the right test for you.

“For the most part, if someone can exercise, we want people to exercise and get on a treadmill,” he said.

Even if you have symptoms during exertion, the test can be used. 

“If those patients are exercising on their own — not in a healthcare facility, not hooked up to an EKG machine, not with a cardiologist and a nurse standing next to them and not with a defib just next to the treadmill — their exercise in an outside environment is giving the patient a higher risk than the risk would be here on the treadmill,” he said. “If that patient had a drug test — didn’t get on a treadmill, didn’t have symptoms and the pictures are normal — that doesn’t exclude the fact that patient may be pushing himself harder than what the drug was able to do.”

When is a chemical stress test best?

  • Patients with orthopedic conditions, like knee or hip problems
  • Patients with an enlarged aorta
  • Patients who wheeze

The patients may not be able to physically boost their heart rate – a critical factor for proper evaluation. 

“Patients who can’t exercise or we would make them worse from an orthopedic standpoint by doing an exercise test, and pushing them too hard, those patients we may put on a treadmill slowly but do a chemical test while they walk slowly for five or six minutes,” Najman said.

Advocate for yourself and ask questions to make sure you get the right test for you.

“We’ll often change what was ordered so it’s better for the patient,” Najman said.

High-risk patients typically receive supplemental imaging, like an ultrasound of the heart, which increases accuracy of the stress test. EKGs alone are about 70 percent accurate, meaning that 3 out of 10 people that have normal EKGs actually have heart problems.