ECG with physical activity: how to do, normal parameters, interpretation

In the study of the electrical activity of muscle heart cells - ECG with exercise - the ability of the myocardium to respond to exercise in a controlled clinical environment is assessed. Thanks to this ECG cardiologists are able to obtain the most important parameters of the heart in conditions close to natural, as the patient's body is in motion.

ECG stress test with physical activity compares the coronary circulation of the same patient at rest and under physical stress, showing the frequency, regularity and duration of heartbeats and the ability of the cardiovascular system to endure stresses and provide blood flow to the myocardium.

And the results of this study can reflect both the general physical state of a person and indicate cardiovascular pathologies, primarily coronary heart disease.

[1], [2], [3], [4], [5]

Indications for the procedure

Healthy people with exercise ECG spend during periodic surveys of professional athletes, flight crews of civil and military aviation. Such  electrocardiograms  are candidates for contract service in the army, special forces of law enforcement agencies and rescue services.

ECG with physical exertion for children is required either to assess the possibility to engage in a particular sport, or to clarify the causes of complaints of a child or adolescent for heart palpitations and pain in the heart.

Indications for an ECG with a load for diagnostic purposes include:

• ischemic heart disease, and in its presence - monitoring the state of the myocardium;
• control of cardiac activity in patients who underwent a heart attack or aortocoronary bypass surgery;
• heart valve flaws (chronic aortic regurgitation );
• sinus arrhythmia;
• stenosis of the coronary arteries;
• violations of atrioventricular conduction (atrioventricular blockade of the heart), etc.

Corresponding ECG parameters with load - taking into account the results of other examinations - serve either as a confirmation of the diagnosis, or can be an objective reason for its exclusion.

In addition, this study of cardiac muscle helps to evaluate the effectiveness of a specific program for the treatment of cardiovascular diseases, and also to establish the limits of acceptable, safe for the heart loads before the beginning of rehabilitation after myocardial infarction or cardiac operations (bypass, angioplasty).

If necessary, the doctor to whom you applied will give a referral for the examination and tell you where to do the ECG with physical exertion (in the same medical institution or any other).

[6], [7], [8], [9], [10]

Preparation

The preparation for this study is that the patient should not drink drinks with caffeine, alcohol and chocolate, and also smoke within a day before the test. And the last meal should be three to four hours before the procedure. Also, for a minimum of two days, physical exertion should be avoided.

In addition, appointing an electrocardiogram stress test with physical exertion, the doctor warns male patients about stopping for three days taking any medications to improve erection (Viagra, Cialis, Levitra, etc.).

Also, patients should inform the doctor of all medications they take, in particular cardiotonic and antiarrhythmic drugs - to avoid a distorted ECG result.

[11], [12], [13]

Technique ECG with physical activity: how to do, normal parameters, interpretation

The technique of carrying out the stress electrocardiologic test depends on the method of physical activity:

• usual squats (not less than 20 in 45-60 seconds),
• step-platform (descent and lifting with both feet with the same intensity),
• on the treadmill (running at a moderate pace for 20-25 seconds),
• on a veloergometer (a computerized exercise bike, the pedal of which should be turned with a certain number of revolutions within three minutes). In addition to indications of the heart, when loaded with a veloergometer, changes in blood pressure are simultaneously recorded (for which the arm cuff for measurement of blood pressure is put on hand).

How does the ECG work with the load? Regardless of the technical component of the study, the procedure begins with the installation of 6-9 electrodes on the chest (in clearly defined places - at the left and right edges of the sternum, in the left armpit, etc.). Through these electrodes, the electrocardiograph will take readings (the potential difference in the leads) and fix them on an electrocardiogram. Indications are taken twice - ECG at rest and with exercise: the usual ECG (in prone position) is needed to obtain neutral indices with which the parameters of electrical activity of myocardium cells under physical stress will be compared.

The paramedic supervises the patient's condition both during testing and after it - while the heart rate does not return to normal.

Contraindications to the procedure

Among the contraindications for carrying out electrocardiography with physical exertion, experts note:

• recent acute myocardial infarction;
• severe heart defects;
• decompensated or inadequately controlled congestive heart failure;
• acute coronary syndrome;
• unstable angina in severe form;
• severe cardiac arrhythmia, for example, ventricular tachycardia;
• violation of the operation of one or more heart valves;
• severe aortic stenosis, cardiac aneurysm with aortic dissection;
• acute thromboembolism of the pulmonary artery;
• cardiomyopathy of a hypertrophic nature;
• any inflammatory diseases of the heart ( pericarditis, myocarditis, endocarditis );
• acute violation of cerebral circulation;
• hypertension of the third degree;
• inflammation of the venous walls with the formation of thrombi;
• presence of a pacemaker.

[14], [15], [16], [17]

Normal performance

If after 20-30 sit-ups (their specific number depends on the age of the patients) performed for one minute, the heart rate (resting rate of 60-90 beats / min) increases within 20%, then this is the ECG norm with the load. After all, the increase in heart rate and the increase in blood pressure is a healthy response of the cardiovascular system to physical activity and means that the heart can cope with the pumping of blood. Norm means also the definition of rhythm as sinus.

An increase in heart rate of 30-50% indicates a reduced heart rate, and, therefore, the presence of problems with his work. Specialists note that when interpreting the results of electrocardiography, the conclusion about the presence of coronary heart disease (in particular, subendocardial) determines such indicators of ECG with a load as horizontal depression of the ST segment (in leads V4, V5 and V6); coronary insufficiency gives ventricular arrhythmias against the background of the same depression of the ST segment, and unstable angina - changes in T-waves and the position of the T wave on the isoelectric ECG line.

Patients should understand that the description of the ECG conclusion with the load (as well as the usual ECG) is information for cardiologists, which gives grounds for conclusions about the state of the heart and the diagnosis. Its decoding is carried out only by specialists in the field of  electrocardiography, which are not obliged to explain to patients what the terms in the conclusion of ECG mean (the teeth P and T, the intervals RR, ST, PQ, etc.). Or that the thoracic leads are curves of electrocardiograms recorded from the electrodes fixed on the chest, and the QRS complex refers to the period of excitation of the blood-pumping heart ventricles ...

However, the doctor should explain the patient the basic parameters of the ECG with the load. Changes in the ST segment, ventricular arrhythmia and T-wave anomalies do not necessarily represent a positive outcome. Moreover, if at an ECG with exercise, 85% of the maximum heart rate is not reached, then a negative result of diagnostic value does not. But with a positive result, the probability of myocardial ischemia is almost 98%.

[18], [19]

Complications after the procedure

During the ECG stress test with physical exertion, the patient may experience fatigue, dizziness, malfunction of breathing, frequent heartbeat, chest discomfort, pain in the legs. It is necessary to inform the doctor about this in order to prevent possible complications after the procedure, when the vegetative symptoms grow (violation of coordination of movements, intentional tremor, leg cramps); there are signs of violation of pulmonary ventilation and perfusion ( dyspnea, wheezing, pallor of the skin, cyanosis); sustained ventricular tachycardia; pain in the chest increases.

In the presence of myocardial ischemia, the hypertensive response develops with an increase in systolic blood pressure above 250 mm Hg to increase physical activity.

Problems with the cardiovascular system cause consequences after the procedure in the form of atrial fibrillation, ventricular tachycardia and ventricular fibrillation, conduction disorders, acute heart failure and myocardial infarction; bronchospasm (with bronchial asthma physical effort); fainting or a stroke.

[20], [21], [22], [23]