Diagnostic Services

The first step in starting the right treatment for a cardiovascular condition is reaching the correct diagnosis. At the Montana Heart Center, our cardiologists use these diagnostic tests:

Echocardiography – The use of high frequency sound waves to make moving images of the heart.

Transesophageal echocardiography (TEE) – Echocardiograph tests done via the esophagus to get clearer images of the heart.

Stress echo – Echocardiography tests that examine the heart during exercise.

Treadmill stress testing – Electrocardiogram (ECG) tests of the heart during exercise.

Dobutamine stress echo – Echocardiogram tests that use a medication to increase heart rate and simulate exercise.

Nuclear cardiology – The use of radioactive tracers to examine blood flow in the heart.

Cardiac catheterization – The use of thin, flexible tubes called catheters to diagnose problems with the coronary arteries.


These tests use high frequency sound waves, also called ultrasound, to examine the structure and function of your heart. To do the test, a trained technician moves a device called a transducer over your chest. Sound waves from the transducer bounce off your heart, and the ultrasound machine uses them to create images. These images move in real time, which gives your doctor information to help diagnose your heart condition.

To learn more about echocardiography, visit the American Heart Association at


Transesophageal echocardiography (TEE)

This procedure uses high frequency sound waves to produce exceptionally clear pictures of your heart. Your doctor inserts a probe down your throat and into your esophagus. At the end of the probe is a device called a transducer, which sends out ultrasonic sound waves that bounce off your heart. The reflected waves are sent to the ultrasound machine, which creates moving images of your heart as it beats.

To learn more about transesophageal echocardiography, visit the National Library of Medicine at


Stress echocardiography

If your doctor needs to see how well your heart muscle is pumping blood, he or she may use a test called stress echocardiography, or stress echo. You’ll have a standard echocardiogram first, to show how your heart pumps at rest. Then you’ll walk on a treadmill or pedal a stationary bike until your heart reaches a target rate or you are too tired to continue. The technician may also stop you if you have chest pain or other signs of trouble. While your heart rate is increasing, and when it reaches its peak, echocardiogram pictures show whether any parts your heart muscle are not working well. This can mean that blocked or narrowed arteries are reducing the blood flow at those places.

To learn more about stress echocardiography, visit the National Library of Medicine at


Treadmill stress test

This test measures how well your heart functions during exercise. To take this test, you will first have a number of adhesive patches with electrodes placed on your chest. Then you will walk on a treadmill or pedal a stationary bike. As you walk or pedal, the work will get increasingly harder from more resistance on the bike or a faster pace and steeper angle on the treadmill. This will continue until you great a target heart rate or become too tired to continue. The technician will also stop the test if you have chest pain, your heart rhythm changes, or you have other signs of trouble. As you exercise, an electrocardiogram machine will measure the electrical activity of your heart. A treadmill test can reveal abnormal heart rhythms or reduced blood flow in your heart.

To learn more about treadmill stress tests, visit the National Library of Medicine at


Dobutamine stress echocardiography

Stress echocardiography can show how well your heart pumps during exercise. In most cases it involves walking on a treadmill or pedaling a stationary bike until your heart reaches a target rate or you are too tired to continue. People who are not able to exercise can still take this test, by using a medication such a dobutamine. This medicine makes your heart beat faster and harder, the way it would if you were exercising. As the medicine is given through an intravenous line, echocardiogram images will show if any parts of your heart muscle don’t function properly during this increased heart rate. That could mean your heart is not getting enough blood due to blocked or narrowed arteries.

To learn more about stress echocardiography, visit the American Heart Association at


Nuclear cardiology

Your cardiologist may use a nuclear cardiology test to determine how well blood is pumping through the parts of your heart. This test uses radioactive materials called tracers to reveal possible blockages in the coronary arteries, problems with the heart’s valves and other disorders that weaken the heart. It can also tell if you’ve had a previous heart attack. During a nuclear cardiology test, a technician will inject the tracer into your vein. The tracer attaches to your red blood cells and travels through your heart, where if forms an image picked up by a special camera. This camera is timed with an electrocardiogram, and a computer combines this information to create images that show the movement of your heart.

Nuclear medicine tests are very safe. The amount of radiation in the tracer is the lowest possible to achieve accurate imaging. According to the Society of Nuclear Medicine, these tests do not pose a demonstrable health risk.

To learn more about nuclear cardiology, visit the National Library of Medicine at


Cardiac catheterization

This procedure is used to diagnose and treat narrowed or blocked arteries in your heart. It provides access to these vessels so your doctor can perform tests such as angiography (taking X-ray images of heart vessels using a special contrast dye), and treatments such as angioplasty (opening narrowed or blocked areas with a balloon-tipped catheter).

To perform a cardiac catheterization, your doctor will make a very small cut in your skin to access an artery in your wrist or leg. He or she will then insert a thin, flexible tube called a catheter into the artery and maneuver it to your heart. For angiography, a contrast material, or dye, will be injected into your coronary arteries to illuminate the site of the blockage on an X-ray.

Besides measuring blood flow in the heart, cardiac catheterization is used to evaluate how well heart valves are working and to take samples of heart muscle to biopsy. It can also reveal heart defects and the overall size and shape of your heart.

To learn more about stress cardiac catheterization, visit the National Library of Medicine at