What is it?
Stress testing, also known as ergometry, is a common study used to diagnose coronary artery disease and to assess a person’s exercise capacity.
It allows the heart’s response during exercise to be assessed. During the stress test, an echocardiogram may also be performed (called a “stress echocardiogram”) or radioisotopes may be injected into the bloodstream (called an “isotope stress test”). These studies can provide more information about the structure and blood flow of the heart.
The Magnasalud Clinic has a treadmill for performing stress tests. Compared to the cycle ergometer (bicycle), it is the method that most frequently allows the heart rate and physical capacity objectives sought to be achieved. This is because it is more physiological, since most individuals are better trained to walk than to ride a bicycle. For this reason, it is the most commonly used method for performing it.
How is it performed?
Before performing a stress test, a physical examination, a medical history and an electrocardiogram are performed.
Initially, 10 electrodes are placed on the chest to monitor the electrocardiogram (ECG). The so-called BRUCE protocol is mainly used. It consists of a succession of 3-minute stages that progressively increase the slope and speed. The continuous ECG is monitored and ECGs are acquired at rest, during each stage and at the end of the effort.
Blood pressure measurements are taken at the beginning, during each stage and several times during recovery. The aim is to reach the maximum heart rate for age (220-age) and the test is then stopped or due to limiting symptoms (pain, fatigue, dizziness). The workload performed is assessed in patients with suspected ischemic heart disease if it exceeds 5 minutes of exercise and reaches 85% of the maximum heart rate for age.
The report will reflect the protocol carried out, when it is interrupted, the metabolic equivalents reached (physical capacity) called METs, and if there is data on the ECG of coronary disease (ischemia, lack of blood flow to the heart), its extent, onset and duration. If there has been angina pectoris, when it started and when it has subsided. If there have been arrhythmias, the response of blood pressure and frequency to exercise and functional capacity (physical capacity for age).
What is it for?
A stress test is capable, in many cases, of detecting lesions in the coronary arteries before the patient has noticed any symptoms. In this way, these lesions can be treated before they completely obstruct the artery and cause the much-feared acute myocardial infarction.
Most common indications:
- Diagnostic and prognostic assessment of ischemic heart disease (myocardial infarction, angina, etc.)
- Assessment of physical capacity in other diseases: valvular, heart failure.
- Assessment of the need for a pacemaker in patients with symptoms of fatigue when walking and slow heart rate.
- Assessment of exercise-induced arrhythmias.
- Assessment of functional capacity and training programs in athletes (use of oxygen consumption obtaining parameters of maximum oxygen consumption and anaerobic threshold).
- Assessment prior to starting sports in people over 35-40 years of age.
How to go to the test:
- Comfortable sports clothing and shoes.
- Do not eat, drink coffee, alcohol or tobacco 3 hours before.
- Do not do intense physical activity or exercise 12 hours before.
- Consult your doctor if any of the medications you are taking should be withdrawn two days before the test.
Complications of the stress test:
It is a procedure considered safe, although one death has been described for every 10,000 tests performed. The greatest danger is mainly in patients with recent myocardial infarction, previous arrhythmias and in general in patients with advanced heart disease.
Also described, although also rare, during the test are: myocardial infarction, heart failure, loss of consciousness due to drops in blood pressure and rhythm disorders. The latter are the most frequent, although usually transient.
The patient must sign an informed consent form prior to the test. It will state what the test consists of.