L’electrocardiogram (ECG) is an exam that records theelectrical activity of the heart. As the name suggests, the stress EKG is obtained when the person exerts a physical effort, for example on a stationary bicycle.

The exercise electrocardiogram therefore makes it possible to observe the variations inheart activity, heart rate and blood pressure during muscle exercise, according to a standardized procedure.

The aim is to study the activity of the heart when it is under strain, which can detect abnormalities that are not seen when the ECG is performed at rest.

Indeed, many modifications occur during an effort, to allow the organism to adapt: ​​a greater quantity of oxygen is necessary, which is done thanks to an increase in blood flow, to a more ventilation. important and redistribution of blood to active muscles. The heart has to put in extra effort, increasing the frequency of the beats.

The exercise electrocardiogram is a very useful test in the diagnosis and evaluation of heart disease.

It is mainly used for the diagnosis and evaluation of coronary heart disease (insufficient blood supply to the heart), in particular to determine the risk of heart attack (risk stratification).

Other situations may justify doing an exercise ECG:

• valve pathology
• a heart rhythm disorder
• congenital heart disease.

It’s a fairly easy exam to implement, completed in less than an hour. It consists in making the patient practice a muscular exercise, while recording his electrocardiogram and various clinical parameters, such as the arterial pressure.

If possible, it is recommended to have an empty stomach 2 hours before the exam.

As with a traditional ECG, the medical staff first place electrodes on the chest, after having “scraped” the skin with a very fine sandpaper, in order to remove the dead cells and obtain a better signal.

Two types of effort can be made:

• un “isometric” effort, characterized by a permanent muscle contraction without displacement (which allows to study more precisely the activity of the left ventricle)
• un “dynamic” effort, which further increases cardiac output and oxygen uptake. It is mainly this type of effort, performed on a stationary bike or on a treadmill, that is used in practice.

During the examination, the doctor will note any symptoms that the patient may experience at different levels of exercise, such as chest pain, shortness of breath, palpitations or dizziness. Blood pressure and heart rate are measured.

Note: some situations do not indicate performing an exercise ECG, in particular the risk of a heart attack that is too high. You should know that the risk of serious accident (myocardial infarction and cardio-circulatory arrest) is less than 1 in 2 examinations.

The stress ECG will allow the doctor to see how the heart reacts when it comes to extra effort. In case of’coronary insufficiency, that is, plaques “blocking” the coronary arteries and limiting the blood supply to the heart, the lack of oxygen compared to the needs during muscular exercise can lead to changes in the electrical activity recorded.

Depending on the results, it will be possible to establish a prognosis (risk of aggravation of the disease).

If necessary, other examinations may be ordered to complete the assessment, such as an echocardiogram, a cardiac doppler measurement of exhaled gases, etc.