Explained: Stress Tests, Echocardiograms, and Radiology

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Stress Tests: What are they?

Stress tests are simple procedures that determine the heart's ability during physical activity. The tests are non-invasive and require the patient to perform activities like running on a treadmill or riding a stationary bike to gauge their ability during increasing speed or rigor. These tests can reveal problems with blood flow as well as the strength of the patient's heart.

If a patient is unable to perform physical activity, they may partake in a nuclear stress test. Essentially, a drug is given to mimic the effects of exercise. The drug is used to increase heart rate which allows for nuclear testing. Then, an antidote is given to take away symptoms and conditions. Two doses of radioactive material are used to influx the heart rate. The patient needs to squeeze the ball and release it in hand and tap their feet up and down. Sometimes, the heart rate started dropping rather than rising. In that case, the antidotes are given earlier. Antidotes will also be given in the case of an emergency and the test will be compromised for patient safety.

Process and Function of Stress Tests

The typical process of a stress test simply revolves around a guided exercise activity where the nurse will increase the intensity of the activity over time. Usually, the patient is set a goal heart rate based on their age, heart conditions, regular exercise, and other factors. The patient can stop whenever they feel uncomfortable or tired. EKGs are taken continuously throughout the stress test as electrodes are linked to the patient while performing the test.

Stress tests are used for a variety of functions including but not limited to diagnosing coronary artery disease (when arteries become blocked or damaged), diagnosing arrhythmias (heart rhythm problems), guiding heart treatment, or checking heart condition before surgery.

Echocardiograms: What are they?

Before and after stress tests, doctors will often ask to perform an "echo" or the short form for an echocardiogram. Echos are painless, non-invasive tests without radiation that gives crucial information about heart processes and function.

Different types of Echo

1. Transthoracic Echocardiogram: Most common type that utilizes an ultrasound beam against the skin aiming through your chest to your heart. Ultrasound is essentially sound waves that create images and is pretty much the same as the procedure for a pregnant woman observing the fetus.

2. Transesophageal Echocardiogram: After giving medications, a flexible tube will be guided down the throat into the stomach. A transductor positioned inside will send sound waves to the heart creating an ultrasound image of the heart and its movement.

3. Stress echocardiogram: Essentially, a transthoracic echocardiogram is taken before and after a stress test is performed. This is because some heart problems related to blood flow can only be seen after physical exercise is performed.

Radiology Imaging: What is it?

Also known as myocardial perfusion imaging, this is a continuation of the nuclear stress test explained above. Along with the heart rate boosting drug, another radioactive substance called a tracer is introduced into the bloodstream. They will use a special camera known as a Cardiac PET (positron emission tomography) to capture images of the blood flow throughout your body. This process exposes the patient to radioactive material and should be done with caution and only in necessity.

Additional Sources: The Mayo Clinic and Cleveland Clinic