How to decipher the cardiogram of the heart?

Formation of the conclusion on the electrocardiogram (ECG) is carried out by a doctor of functional diagnostics or a cardiologist. This is a difficult diagnostic process that requires special training and practice. A doctor describing an ECG should know the basics of cardiac electrophysiology, variants of a normal cardiogram, and be able to identify functional and morphological changes in the heart. He should be able to analyze the violation of the functions of automatism, conduction, excitability of the heart, evaluate the effect of medications and other external factors on the formation of ECG waves and intervals.

The description of the electrocardiogram includes several successive stages. First, the gender and age of the patient are evaluated, since different age groups may have their own ECG features, and the cardiogram is different for men and women. Then the duration and amplitude of the waves and intervals of the cardiogram are determined. After that, the rhythm is assessed, the features of the position of the heart in the chest, conduction disturbances, signs of focal changes in the myocardium and hypertrophy of the heart departments are analyzed. Then the final conclusion is formed. If possible, the ECG is compared with previously recorded films of the same patient (analysis in dynamics).

Analysis of the P wave involves measuring its amplitude, duration, determining polarity and shape. Determine the duration of the P-Q interval.

Analysis of the ventricular QRS complex is an assessment of the ratio of the teeth in all leads, measuring the amplitude and duration of these teeth.

To analyze the ST segment, it is necessary to determine its displacement up or down relative to the isoelectric line and evaluate the shape of this displacement.

When evaluating the T wave, you need to pay attention to its polarity, shape, amplitude.
Then the Q-T interval is measured and compared with the proper value, determined by a special table.

Normal ECG

Normally, the rhythm of the heart is regular, correct, its source is the sinus node. Sinus rhythm at rest has a rate of 60 to 100 beats per minute. The heart rate is determined by measuring the distance between adjacent R waves on the ECG (R-R interval).

The direction of the so-called electrical axis of the heart is determined, showing the position of the resulting electromotive force vector (angle alpha). It is indicated in degrees. The normal axis corresponds to an alpha value between 40 and 70 degrees.

The presence of turns of the heart around its axis is determined.

Heart rhythm disorder

A heart rhythm disorder, or arrhythmia, is diagnosed if the following ECG abnormalities are detected:

• an increase in the heart rate of more than 100 per minute or a decrease of less than 60 per minute;
• wrong rhythm;
• non-sinus rhythm;
• violation of the conduction of an electrical signal through the conduction system of the heart.

Arrhythmias are divided into the following main groups.

On the basis of a violation of the formation of an impulse:

1. violations of automatism of the sinus node (sinus tachycardia, bradycardia, arrhythmia);
2. ectopic (non-sinus) rhythms caused by the predominance of automatism of non-sinus centers (slip-out, accelerated ectopic rhythms, pacemaker migration);
3. ectopic rhythms due to the re-entry mechanism (paroxysmal tachycardia, atrial and ventricular fibrillation and flutter).

On the basis of conduction disturbance.