The electrocardiogram is the main way to check the status and functioning of the cardiovascular system. This procedure is recommended to be carried out annually as part of a routine health check, even to persons without pathologies. Most often, the result is given to the patient’s hands, which, having misinterpreted the “strange” comments of a specialist, can immediately attribute to himself many non-existent diseases. How correctly to decipher an electrocardiogram what to expect from it?

Principles of the procedure

decipher the ECG, what to expect from it

Perhaps, the cardiogram is one of the most simple and painless examinations you can imagine, and one of the most affordable, since it is done in almost all district municipal polyclinics at the expense of the state budget. And, in contrast, for example, from X-rays, there is no need to take a queue for several weeks: the direction is issued almost immediately.

  • The patient must enter the office, being at rest. Before the examination active physical exercises are forbidden, and even if you walked very quickly, you must first catch your breath (3-5 minutes) and only then pay a visit to the doctor. Otherwise, the results may be distorted. In addition, alcohol and coffee as well as medications are prohibited on the day of the procedure.
  • In order for a specialist to take readings, the patient must expose the upper part of the body, lie on his back, after which electrodes on suction cups are attached to him. Their main mass is located on the left side, the line is perpendicular to the body. Fixation points must be treated with a special solution that contributes to the conduction of current.
  • In some cases, “tucks” are added to the wrists and ankles: in this case, the doctor asks you to remove or roll up the pants.

The duration of the procedure is usually no more than 15 minutes, and most often shortened to 5-7 minutes. However, it depends on what type of cardiogram you need to get: sometimes you need to do a test with a load that will show how the heart works in hyperactive mode when the pulse rises. Most often, it is necessary for athletes and in all situations in which a person’s susceptibility to increased physical activity is monitored. In this case, the patient, holding the electrodes on him, for 1-2 minutes. doing exercises under the supervision of a doctor: these are mainly fast deep squats. Measurement is performed both during their execution, and after, to find out how quickly the pulse recovers.

What parameters are displayed on the cardiogram?

What parameters are displayed on the cardiogram

The obtained measurements are graphically displayed in the form of intervals and teeth, which have letter designations in Latin. For the uninitiated person, they look like a real “Chinese letter”, but, in fact, it’s not difficult to deal with them. However, before you begin to study all the key points, you should take a look at the picture as a whole and evaluate the overall picture of the rhythm regularity: the alternation of high and low teeth. Ideally, between intervals (a high tooth and a low segment) there should be an absolutely equal distance throughout the contour. The tolerance is 10%.

  • Latin designations play the greatest value: Р - speaks of atrial depolarization, QRS, which is usually a high prong, explains ventricular depolarization. The wide wave T - their repolarization, and U, which often looks almost a straight line, refers to the depolarization of their distal portions.

These moments are taken into account not only separately, but also in the form of segments - for example, RR, by which the pulse is calculated, since these are peak (shock) points in it; or QT, whose lengthening speaks of hypoxia, leading to cardiac arrhythmias.

  • When reading the finished result, the focus is on QT, QRS, ST, as well as EOS. These nuances, combined with heart rate and heart rate, are enough to make a primary diagnosis. In children, it is also necessary to consider PQ and QT; in addition, R.'s tooth is taken separately.

Special attention should be paid to the phrase "myocardial hypertrophy", which is often present in the field of doctor's marks. It speaks of a certain stretching of the chambers and thickening of the heart muscle, which does not always indicate pathology (most often ischemia), but may be due to obesity, heavy physical exertion, obstructive lung diseases, cardiomyopathy, chest deformities.

Regulatory values ​​for different categories of persons

Regulatory values ​​for different categories of persons

It should immediately be said that with serious pathologies (if they are identified), the specialist will not let you go, handing the results of the ECG. And therefore, if the doctor did not send for additional examinations (holter, ultrasound, etc.), you can hardly find something really scary when deciphering yourself. However, to compare the result with the established norm never hurts. In ECG decoding in adults, it is usually worth paying attention to the pulse (HR), which should be in the range of 60-90 beats / min., As well as some factors that are derived from the graph data.

Teeth and spacing

Amplitude (mm)








P-Q (R)





up to 1/4 R




I-a VF to 20

V1-V6 up to 25



up to 20





less than 0.12

less than 6


I-a VF to 6

V1-V6 to 17



To make the decoding of the norm in the table, you need to take into account the tape recording speed. To date, there are 2 options: 25 mm / s, where 1 cell of electrical tape equals 0.04 s, or 50 mm / s, where, therefore, 1 cell is 0.02 s. Thus, it is precisely by the number of cells between those or other intervals (height and width) that conformity or non-compliance with standard indicators is determined. The above values ​​are for people over 12 years old, so ECG decoding is the same for students and adults. In addition to the points already mentioned, it should be remembered that RR is characterized by parameters 0.62-0.66-0.6, QT should not exceed 0.4 s, and ST is asymmetric and looks up.

  • The situation looks somewhat different when it comes to children's examination, since even the pulse here increases greatly: in newborns, it can normally be 160 beats / min, in a one-year-old baby - 135 beats / min, and with time (up to 12 years) decrease until it is in the range of 70-75 beats / min.
  • The data of normal ECG indices for teeth and intervals also change: values ​​of 0.6-0.1 s are typical for QRS, 0.2 s for PQ, and less than 0.4 s for QT. Directly P wave should not exceed 0.1 s.

Also, doctors pay attention to EOS, which is formed by an isoline: normally, the R-wave on an ECG is higher than S, and during inversion there is a likelihood of ventricular disease.

We should also say that the appearance of the cardiogram changes during pregnancy due to the displacement of the heart itself, as a result of which the electrical axis on the paper will shift.

When do deviations appear?

Sinus arrhythmia is characteristic of student outcomes.

The bulk of the nuances causing questions arise even at the moment of reading the marks of a specialist on rhythm. As already mentioned, ideally it should be sinus, but what if the phrase sounds different?

  • Sinus arrhythmia is characteristic of the results of students and children, where it is taken as the norm, but in other cases it often becomes the reason for a visit to a cardiologist, since it can be not only a consequence of rheumatic fever, infections, heart disease or heredity.
  • Sinus bradycardia is characterized by a low heart rate (up to 50 beats / min), which is the norm for the body at rest (sleep), as well as for athletes. If this is recognized as a pathology, the cause may be a weak sinus node. The danger is to increase the likelihood of frequent syncope, hypoxia.
  • Sinus tachycardia, on the contrary, indicates an excess of heart rate, which is natural for physical activity, but at rest is a pathology inherent in fevers, high pressure, thyrotoxicosis, severe blood loss, anemia, dehydration.
  • Extrasystole is easy to see with the naked eye, because it looks like a schedule with no systematic effect. In an even pulse, extraordinary contractions appear, followed by a long pause to compensate for them. Patients with extrasystole often complain of sudden tremors in the chest, panic attacks.
  • Atrial fibrillation is manifested in the form of a strong shock, followed by a stray pulse, dizziness, fear, sweating, loss of consciousness, after which it is often necessary to empty the bladder. The cause is often the intoxication, thyrotoxicosis, heart disease, diabetes.
  • Atrial flutter is monitored after heart surgery, for obstructive pulmonary diseases, as well as heart failure. It is not characteristic of a healthy person, since it speaks of an acute form of pathology.

This, of course, not all moments that may be present in the cardiogram, but it is the rhythm of heart contractions that requires special attention to itself. And, in most cases, it is more than enough to decide whether a new visit to the doctor is necessary. However, if the specialist who received the result did not recommend drawing up a course of therapy and did not suggest additional checks, you may not be afraid of strange notes and graphs.