What is stress echocardiogram or stress echo?
A stress echocardiogram is a functional test in which, a stress test is combined with an echocardiogram to increase the accuracy of the stress test. After walking or running on a treadmill, as one does at the gym, a sonographer takes some images by an ultrasound machine called an echocardiogram. Some of the reasons this test is performed (indications) are listed below.
What are some of the indications for stress echocardiogram?
- One of the main indications for stress echocardiogram is identifying and monitoring reduced blood flow to the heart muscle (ischemia). Ischemia is usually due to a significant narrowing in the heart’s major arteries. Usually, at the early stages, ischemia may not cause any symptoms at rest and the only way to diagnose it is by putting extra pressure on the heart muscle in the form of exercise. When we exercise, our body requires more energy and oxygen. Subsequently, the heart has to work harder and faster to meet the requirements. In turn, the heart muscle needs more oxygen and energy (more blood supply via coronary arteries) to work harder. Now, if there is a narrowing of the coronary arteries, the heart muscle will be deprived of oxygen, and the person develops chest pain (exertional angina) accompanied by ECG and echocardiogram changes during the stress test.
- To assess the severity of some types of heart valve disease to guide further management, like surgery. One of the primary heart valve diseases that need this type of assessment is Aortic Valve Stenosis (AS). AS is a type of disease that progresses very slowly over many decades. As such, the patient usually becomes accustomed to the symptoms, and they reduce their physical activities according to the severity of the disease. The only way to assess their physical ability is to “stress” them in a controlled fashion.
- Another complaint which is frequently assessed by stress echocardiogram is dyspnea (shortness of breath). On many occasions, patients report dyspnea only when they perform physical activity and not at rest. A stress echocardiogram is a perfect test to create such an environment to reproduce patient’s symptoms in a controlled manner and assess cardiac parameters.
- A stress test or stress echocardiogram is an excellent opportunity to witness patients complaints first-hand and assess their exercise capacity. Seeing a complaint in person is far superior to listening to the description. One can assess patients fitness, and on many occasions, respiratory (Lung-related) diseases can be identified and differentiated as the leading cause of the patient’s complaint.
A normal stress echocardiogram sample shows excellent and vigorous heart contraction after 10 minutes of exercise. Such excellent stress echo rules out the presence of significant blockages in the heart’s arteries with high certainty.
How is a stress echocardiogram performed?
An echocardiogram at rest is performed before you start exercising on the treadmill machine. These are called the “baseline echocardiogram images”. You will exercise for a specific amount of time while being monitored by an ECG machine. (Exercise Electrocardiogram).
According to a specific protocol, the treadmill machine speed and gradient will increase every 3 minutes. You need to achieve at least 85% of the predicted maximum heart rate for your age for the test to be conclusive and accurate. You will then immediately lie on the bed, and another echocardiogram will be done. You will sometimes be asked to hold very still, breathe in and out very slowly, hold your breath, or lie on your left side.
These images will be compared with the baseline images, side by side, to make a diagnosis. Specific measurements are made at rest and after the stress for particular valvular pathologies like aortic stenosis.
A stress Echocardiogram takes about 30 to 45 minutes. At Heartcare Sydney, we use state-of-the-art equipment, including the latest Echocardiogram machine and stress system for the most accurate results. You need to dress as if you were going to the gym on the day. Comfortable clothes and shoes to walk (and potentially run) on the treadmill.
CT Coronary Angiogram and Coronary Calcium Score Vs Stress Echocardiogram:
A common question that is usually asked is whether you could have a CT coronary Angiogram or Check your coronary calcium score instead of doing a stress echocardiogram. Suffice to say that, these are very different tests and each is designed to answer a specific question. Although CTCA and stress echocardiogram at times could be used interchangeably, they should never be considered at the same level. I will shortly explain more about this question in a coming blog post.