ECG indicators and decoding of the heart
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).
To interpret an electrocardiogram means to evaluate the activity of the biopotential of the heart muscle. This allows the doctor to detect a violation of the rhythm frequency, ischemia, hypertrophy of the ventricles, atria, and a number of other abnormalities.
The process of decoding the ECG (data from a cardiographic picture) consists of measuring the length, magnitude of the segments and the amplitude of the oscillation of the teeth.
Studying the results of a healthy person will help to compare the data, and identify existing heart problems with pathological changes.
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.
Decoding ECG of the heart
First, consider the decryption plan, for this you should establish:
- the nature of the heart rhythm and the determination of the exact value of the contractions in the time interval
- cardiac biopotential cycle
- recognition of excitation sources
- conductivity assessment
- P wave and ventricular QRST
- designation of the axis of signal propagation and the position of the heart relative to its
The work of the heart is determined by emerging biopotentials.
ECG decoding is a graphical display of the intensity of a given discharge, which helps to identify malfunctions in the work of the heart departments.
The rhythm of contractions of the heart muscle is determined by the duration of the measurement of RR intervals. If their duration is the same or marked by fluctuations of 10% - this is considered the norm, in other cases we can talk about rhythm disturbance.
ECG indicators and their interpretation
Heart rate (heart rate)
We list the main ECG indicators that interest us on the cardiogram:
- Teeth - characterize the stages of the heart cycle
- 6 assignments - departments of the heart displayed in numbers and letters
- 6 thoracic - record changes in cardiac potentials in a horizontal plane
Interval PQ QRS QT Displays Pulse Conductivity
After familiarizing yourself with the terminology, you can independently try to decipher the results. However, we recall that only the attending physician can make a 100% objective diagnosis.
We begin to measure the height of the teeth from the isoline — the horizontal line with the help of a ruler, taking into account the location of the positive teeth above the straight line and the negative ones below the axis.
Their shape and size depend on the passage of the electric wave and differ in all leads. According to the automatically specified formula, we calculate the duration of the intervals and segments - divide the distance between the segments by the speed of the tape.
The values of the teeth on the cardiogram
P wave - is responsible for the distribution of the electrical signal through the atria. Norm: positive value with a height of up to 2.5 mm.
The Q wave is characterized by the placement of an impulse along the interventricular septum. Norm: always negative, and often is not recorded by the device due to its small size. Its severity is cause for concern.
R tooth - is considered the largest. Reflects the activity of an electrical impulse along the myocardium of the ventricles. His incorrect behavior indicates myocardial hypertrophy. The interval norm is –0.03 s.
S wave - shows the completeness of the process of excitation in the ventricles. Norm: negative and does not exceed 20 mm.
Interval PR - indicates the rate of distribution of excitation in the atria to the ventricles. Norm: fluctuation of 0.12-0.2 s. This interval determines the heartbeat.
T wave - reflects the repolarization (restoration) of the biopotential in the heart muscle. Norm: positive, duration 0.16-0.24 s. Indications are informative for the diagnosis of ischemic abnormalities.
TP interval - shows a pause between contractions. Duration - 0.4 s.
ST segment - characterized by maximum excitation of the ventricles. Norm: a deviation of 0.5 -1mm down or up is permissible.
QRST interval - displays the time period of ventricular excitation: from the beginning of the passage of the electrical signal to their final reduction.
Decoding ECG in children
The norms of children's indications differ markedly from the values of adults. For ECG decoding in children, you should track the curve and compare the digital parameters of the teeth and intervals.
The following are considered the norm:
- deep Q-wave position
- sinus arrhythmia
- QRST ventricular interval is susceptible to alternation (a change in the polarity of T waves)
- atrial movement of the rhythm source is noted
- as a child grows up, the number of chest leads with a negative T wave decreases
- large atria determine the height of the P wave
- the child's age affects the ECG intervals - they become longer. In young children, the right ventricle predominates.
Sometimes the intensive growth of the baby provokes disturbances in the heart muscle, which can be shown by a cardiogram.
What does the sinus rhythm on the cardiogram mean?
Does ECG decoding show sinus rhythm? This indicates the absence of pathologies, and is considered the norm with a characteristic frequency of strokes from 60 to 80 per minute. with an interval of 0.22 s. The presence of a doctor's record about irregular sinus rhythm implies pressure fluctuations, dizziness, chest pain.
A rhythm indicated by 110 beats indicates the presence of sinus tachycardia. The cause of its occurrence may be physical exertion or nervous excitability. This condition may be temporary, and does not involve a long treatment.
With anemia, myocardium or fever, persistent manifestation of tachycardia with a rapid heartbeat was noted. The decoding of the ECG in this case determines an unstable sinus rhythm, and indicates arrhythmia - an increased frequency of contractions of the heart.
For children, a similar symptom is also characteristic, but the sources of origin are different. These are cardiomyopathy, endocarditis and psychophysical overloads.
The rhythm can be broken from birth, have no symptoms, and come to light during electrocardiography.