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How is an ECG performed and how to prepare for a patient

Как проводится ЭКГ и как подготовиться пациенту

Electrocardiography - a technique for recording and studying the electric fields generated by the heart. Electrocardiography is a relatively inexpensive but valuable method of electrophysiological instrumental diagnostics in cardiology. The direct result of electrocardiography is to obtain an electrocardiogram (ECG).

Electrocardiography is the basis of many diagnostic studies - Holter monitoring, bicycle ergometry, transesophageal ECG recording, ECG using drugs, remote ECG, monitor observation in intensive care units or during operations. A cardiogram is a record of the electrical activity of the heart, which is produced from the surface of the patient’s body - from the upper and lower extremities and chest. To record an ECG (depending on the type of apparatus), electrodes, special suction cups and cuffs are used. Removing the ECG takes 5-10 minutes. ECG recorded at different speeds. Typically, the paper speed is 25 mm / sec. In this case, the 1 mm curve is 0.04 sec. Sometimes, for a more detailed recording, a speed of 50 or even 100 mm / s is used. With prolonged registration of the ECG, a slower speed is used to save paper - from 2.5 to 10 mm / s.

In the new series of articles we will tell you about the specifics of the ECG procedure, as well as how to properly prepare for it and be able to independently decipher the results by comparing your own indicators with the norm.

Электрокардиография (ЭКГ)

Electrocardiography (ECG) - is a non-invasive test, the conduct of which allows you to obtain valuable information about the state of the heart. The essence of this method is to register the electrical potentials that arise during the work of the heart and in their graphical display on the display or paper.

A bit of history. Interest in the electrical activity of the heart arose in the 19th century. German scientists R. Kelliker and I. Muller in 1856 discovered electrical phenomena in a contracting heart muscle. The English physiologist R. Waller in 1873 made the first record of the electrical activity of the human heart. At the beginning of the twentieth century, the Dutch physiologist Willem Einthoven introduced an ECG into clinical practice. In fairness, it is worth saying that Einthoven recorded only three standard leads - I, II and III (the “Einthoven Triangle”). Goldberger suggested three more leads (reinforced leads from the extremities - aVR, aVL, aVF). A little later, Wilson suggested recording chest leads (V1-V6). This formed the current classic ECG of 12 leads. In order to understand what revolution electrocardiography has made in medicine, it is enough to say that in 1924 the ancestor of the ECG Willem Einthoven received the Nobel Prize.

ECG how to prepare

Contrary to the opinion of cardiologists, it is generally accepted that an ECG does not require special preparation. A study of the heart muscle involves avoiding stress, fatigue, and requires complete rest. On the day of the procedure, you need to sleep well, and ignore the morning exercises. If the procedure is scheduled for the morning, then you should avoid a hearty breakfast, but it is better to completely abandon it. With the upcoming daily procedure, you should limit yourself to a light snack 2 hours before the session.

Do not forget to reduce the amount of fluid that affects muscle function. Refuse coffee, tea and other energy drinks. They will help stimulate cardiac activity, and the results will be distorted.

It is advisable to take a shower. You do not need to apply care products on the body, because the components of creams and lotions will contribute to the formation of a greasy film on the surface, which will negatively affect the contact of the electrodes with the skin.

Just before you conduct an ECG, try to relax as much as possible. Sit with your eyes closed, restore breathing - this will provide an even pulse and objective readings of the device.

Is ECG harmful?

The logical question of whether an ECG is harmful can be answered based on the advantages of this diagnostic method:

  • accuracy of information
  • safety and comfort of the session
  • efficiency (10min)
  • lack of health or pregnancy restrictions

As you already understood, it is impossible to harm the health of the ECG, since this method is based on taking heart rate indicators and does not produce any radiation or effects on the body. Moreover, people whose work is associated with constant physical activity, electrocardiography is done almost daily, which once again confirms its absolute harmlessness.


How is an ECG performed if the appointed time is right?

You will be asked to take off your outer clothing so that nothing interferes with access to the chest and free your lower legs. The places where the electrodes will be attached will be treated with alcohol, on which a special gel will be applied.

The next step is to mount the cuffs and suction cups. They are fixed on the hands, in the ankles and chest. Ten electrodes will track the heart rhythm and give an encrypted result.

The heart plays the role of an electric generator. Body tissues have a high degree of electrical conductivity, which allows you to note the electrical impulses of the heart, applying electrodes to parts of the body. Indications of biopotentials are processed by an electrocardiograph, and gives out data in the form of a total picture - the propagation of excitation signals through the muscle in a graphic image. More specifically, the difference in electrical voltage.

The propagation of an impulse to the heart contributes to the depolarization of myocardial cells, during which some of the cells acquire a positive charge, the other part - a negative one. So there is a potential difference. In the case of complete depolarization (reduction) or repolarization (relaxation) of the cell, the voltage difference is not marked. The device records EMF - the electromotive force of the heart.

After an ECG is performed, the doctor gets an idea of ​​the work of the body and the existing abnormalities.

An electrocardiogram is able to detect:

  • arrhythmia
  • ischemia
  • myocardial infarction

ECG how often to do

As we have already found out, this method is absolutely harmless to the body. So you can forget about the risk of getting any complications from frequent monitoring of the heart muscle. On the contrary, the portal “All About Hypertension” recommends electrocardiography when the first alarming symptoms and discomfort occur.

The reason for the ECG are:

  • chest discomfort
  • shortness of breath
  • excess weight
  • chronic stress
  • tachycardia
  • rapid rhythm
  • suspected hypertension

Of course, you should not check every day - it is simply pointless. However, the decision on the frequency of the ECG should be made by the attending physician, based on the anamnesis.

Doctors recommend that people after 40 years of age examine the heart every year, and representatives of more mature age - 1 time per quarter.

The resulting cardiogram will be interpreted, and if necessary, treatment is prescribed. Remember that the disease is better to prevent in advance.

In the following articles, we will consider, using the example of a finished cardiogram, methods for decoding it and complying with the standards.