# How To Read A Cardiogram

## Video: How To Read A Cardiogram

Among the instrumental examination methods that a practicing physician should be fluent in, the leading place is taken by the electrocardiogram. This simple, inexpensive and indispensable method allows diagnosing such serious disasters in the human body as arrhythmias and myocardial infarction. The method is based on the study of the bioelectric activity of the heart. The ECG consists of several waves, segments and intervals, reflecting the process of propagation of the excitation wave through the heart.

## Instructions

### Step 1

Check the registration technique is correct. When recording an ECG, there should be no interference and guidance currents. The reference millivolt should be 10mm.

### Step 2

Analyze the heart rate for regularity and heart rate, determine the source of excitation and conductance. Determine the regularity of heart contractions by comparing the duration of the R-R intervals. At the correct rhythm, the heart rate is calculated by dividing 60 by the R-R interval, expressed in seconds.

### Step 3

Determine the electrical axis of the heart by calculating the algebraic sum of the amplitudes of the teeth of the QRS complexes in any two leads from the extremities, for example, I and III standard leads.

### Step 4

View and analyze the atrial P wave. Measure the amplitude of the wave from the baseline to the apex of the wave, it should not exceed 25 mm. Determine the duration of the wave from its beginning to the end, in a healthy person it is 0.1 s.

### Step 5

Measure the PQ interval, which is the rate of impulse transmission from the atria to the ventricles. It should fall within the range of 0.12 to 0.1 second. Analyze the ventricular QRS complex by measuring the amplitude and duration of each wave in the complex. The width of the entire gastric complex should not exceed 0.1 s.

### Step 6

When analyzing the T wave, reflecting the phase of refractoriness or relaxation of the heart muscle, determine its polarity (direction), evaluate its shape and measure the amplitude. Normally, this tooth should be positive, have the same direction as the main tooth of the ventricular complex, have a gently sloping ascending and slightly more steeply descending knee.