Maximizing the Diagnostic Value of Stress ECG Testing

How does a stress test work?

Usually, cardiac stress tests imply making the heart beat harder and faster by walking on a treadmill or riding a stationary cycle. Doctors assess your response to increased workload by measuring:

•    Blood pressure.
•    Heart rate.
•    Oxygen level.
•    Electrical activity in your heart.
•    How hard your heart is working compared to other people of your age and gender.

 

ECG with exercise tolerance testing- the most popular stress test

For today, the main stress test is an electrocardiogram (ECG) with exercise tolerance testing. These can be quite different examinations in type and duration. The major types are:

•        Cycle ergometry 

A person exercises on a stationary cycle (a special cycle ergometer connected to a computer), with the load varying and increasing differently, depending on the diagnostic tasks. ECG is taken at rest before the test, during its conduction, and after the cessation of physical exercise.

•       Treadmill test.

Differs from the cycle test in that it’s conducted on a treadmill. The treadmill allows for more precise load changes – increasing speed, as well as the incline of the treadmill belt. If a child is being examined, the treadmill is preferable as it has no height or weight restrictions.

 

Is cardiac stress testing safe?

In the absence of contraindications, stress tests are safe. Very few people experience complications. Trained medical professionals, typically a physiologist and a cardiologist, are present during your test in the rare case you experience complications. They assess your performance, data, and symptoms during the tests and provide immediate emergency care if necessary. 

 

What about the diagnostic value? 

Traditionally, exercise ECG remains the first-line non-invasive method for diagnosing coronary heart disease (CHD). It is characterized by accessibility, low cost, and ease of mastery. However, limiting factors include moderate diagnostic accuracy and the requirement for the patient to be able to perform the necessary physical exercise. Additionally, the choice of research method depends on the technical capabilities of the laboratory, preferences, and to a lesser extent, the patient’s physical condition. Some patients find it easier to perform an exercise on a cycle ergometer, while others prefer using a treadmill. People with excess body weight (over 100-110 kg) are offered a treadmill, as are patients with concomitant lower limb pathologies (joint diseases, vascular pathology) who may find it difficult to perform exercises on a bicycle ergometer. For women, it is preferable to assign a treadmill; under otherwise equal conditions, they perform a higher power load on the treadmill, thus achieving a higher heart rate. When performing a test on a bicycle ergometer, women and older patients often stop the exercise before reaching the submaximal heart rate due to extracardiac reasons (fatigue, leg pain, etc.), consequently, the test turns out to be incomplete and diagnostically insignificant. The intake of beta-blockers, coronary vasodilators, and vasodilating drugs is discontinued 1-2 days before the study. If it is impossible to discontinue these medications for clinical reasons (chest pain upon medication withdrawal), the interpretation of the study results will be extremely difficult, and the test itself will be devoid of diagnostic meaning. 

We continue to acquaint you with ECG devices and new technologies, which is a priority for Norav Medical. Today, we focused on the diagnostic value of ECG stress tests. Stay with us, and we’ll be happy to keep you informed about all existing innovations in the field of ECG diagnostics.

 

References:

Bennett, M. T., Gula, L. J., Klein, G. J., Skanes, A. C., Yee, R., Leong-Sit, P., … & Krahn, A. D. (2014). Effect of beta-blockers on QT dynamics in the long QT syndrome: measuring the benefit. Europace, 16(12), 1847-1851.

Hernando, D., Hernando, A., Casajus, J. A., Laguna, P., Garatachea, N., & Bailón, R. (2018). Methodological framework for heart rate variability analysis during exercise: application to running and cycling stress testing. Medical & biological engineering & computing, 56, 781-794.

Sharif, S., & Alway, S. E. (2016). The diagnostic value of exercise stress testing for cardiovascular disease is more than just st segment changes: A review. J Integr Cardiol, 2(4), 341-355.