What ECG indicators are considered normal: interpretation of the examination results. Intervals and waves of the ECG are normal. Main characteristics and changes of the ECG

The electrocardiogram reflectselectrical processes onlyin the myocardium: depolarization (excitation) and repolarization (restoration) of myocardial cells.

Ratio ECG intervals With phases of the cardiac cycle(ventricular systole and diastole).

Normally, depolarization leads to contraction of the muscle cell, and repolarization leads to relaxation.

To simplify further, instead of “depolarization-repolarization” I will sometimes use “contraction-relaxation”, although this is not entirely accurate: there is a concept “ electromechanical dissociation“, in which depolarization and repolarization of the myocardium do not lead to its visible contraction and relaxation.

Elements of a normal ECG

Before moving on to deciphering the ECG, you need to understand what elements it consists of.

Waves and intervals on the ECG.

It is curious that abroad the P-Q interval is usually calledP-R.

Any ECG consists of waves, segments and intervals.

TEETH- these are convexities and concavities on the electrocardiogram.
The following waves are distinguished on the ECG:

• P(atrial contraction)
• Q, R, S(all 3 teeth characterize contraction of the ventricles),
• T(ventricle relaxation)
• U(non-permanent tooth, rarely recorded).

SEGMENTS
A segment on an ECG is called straight line segment(isolines) between two adjacent teeth. The most important segments are P-Q and S-T. For example, the P-Q segment is formed due to a delay in the conduction of excitation in the atrioventricular (AV-) node.

INTERVALS
The interval consists of tooth (complex of teeth) and segment. Thus, interval = tooth + segment. The most important are the P-Q and Q-T intervals.

Waves, segments and intervals on the ECG.
Pay attention to large and small cells (more about them below).

QRS complex waves

Since the ventricular myocardium is more massive than the atrial myocardium and has not only walls, but also a massive interventricular septum, the spread of excitation in it is characterized by the appearance of a complex complex QRS on the ECG.

How to do it right highlight the teeth in it?

First of all they evaluate amplitude (sizes) of individual teeth QRS complex. If the amplitude exceeds 5 mm, the tooth indicates capital letter Q, R or S; if the amplitude is less than 5 mm, then lowercase (small): q, r or s.

The R wave (r) is called any positive(upward) wave that is part of the QRS complex. If there are several teeth, subsequent teeth indicate strokes: R, R’, R”, etc.

Negative (downward) wave of the QRS complex, located before the R wave, is denoted as Q(q), and after - like S(s). If there are no positive waves at all in the QRS complex, then the ventricular complex is designated as QS.

Variants of the QRS complex.

Fine:

Q wave reflects depolarization of the interventricular septum (the interventricular is excitedforged partition)

R wave - depolarizationbulk of the ventricular myocardium ( the apex of the heart and adjacent areas are excited)

S wave - depolarization basal (i.e. near the atria) sections of the interventricular septum ( the base of the heart is excited)

R wave V1, V2 reflects excitation of the interventricular septum,

A R V4, V5, V6 - stimulation of the muscles of the left and right ventricles.

Necrosis of areas of the myocardium (for example, withmyocardial infarction ) causes the Q wave to widen and deepen, so close attention is always paid to this wave.

ECG analysis

General scheme of ECG decoding

1. Checking the correctness of ECG registration.
2. Heart rate and conduction analysis:
   • assessment of heart rate regularity,
   • heart rate (HR) counting,
   • determination of the source of excitation,
   • conductivity assessment.
3. Determination of the electrical axis of the heart.
4. Analysis of the atrial P wave and P-Q interval.
5. Analysis of the ventricular QRST complex:
   • QRS complex analysis,
   • analysis of the RS - T segment,
   • T wave analysis,
   • Q-T interval analysis.
6. Electrocardiographic report.

Normal electrocardiogram.

1) Checking the correctness of ECG registration

At the beginning of each ECG tape there must be calibration signal- so-called reference millivolt. To do this, at the beginning of the recording, a standard voltage of 1 millivolt is applied, which should display a deviation of 10 mm. Without a calibration signal, the ECG recording is considered incorrect.

Normally, in at least one of the standard or enhanced limb leads, the amplitude should exceed 5 mm, and in the chest leads - 8 mm. If the amplitude is lower, it is called reduced ECG voltage, which occurs in some pathological conditions.

2) Heart rate and conduction analysis:

1. assessment of heart rate regularity

   Rhythm regularity is assessed by R-R intervals. If the teeth are at an equal distance from each other, the rhythm is called regular, or correct. The variation in the duration of individual R-R intervals is allowed no more than ± 10% from their average duration. If the rhythm is sinus, it is usually regular.

2. heart rate (HR) counting

   The ECG film has large squares printed on it, each of which contains 25 small squares (5 vertical x 5 horizontal).

   To quickly calculate heart rate with the correct rhythm, count the number of large squares between two adjacent teeth R - R.

   At belt speed 50 mm/s: HR = 600 / (number of large squares).
   At belt speed 25 mm/s: HR = 300 / (number of large squares).

   At a speed of 25 mm/s, each small cell is equal to 0.04 s,

   and at a speed of 50 mm/s - 0.02 s.

   This is used to determine the duration of the teeth and intervals.

   If the rhythm is wrong usually considered maximum and minimum heart rate according to the duration of the smallest and largest R-R interval, respectively.

3. determination of the excitation source

   In other words, they are looking for where pacemaker, which causes contractions of the atria and ventricles.

   Sometimes this is one of the most difficult stages, because various disorders of excitability and conduction can be very confusingly combined, which can lead to incorrect diagnosis and incorrect treatment.

Sinus rhythm (this is a normal rhythm, and all other rhythms are pathological).
The source of excitation is in sinoatrial node.

Signs on the ECG:

• in standard lead II, the P waves are always positive and are located before each QRS complex,
• P waves in the same lead have the same shape at all times.

P wave in sinus rhythm.

ATRIAL rhythm. If the source of excitation is located in the lower parts of the atria, then the excitation wave propagates to the atria from bottom to top (retrograde), therefore:

• in leads II and III the P waves are negative,
• There are P waves before each QRS complex.

P wave during atrial rhythm.

Rhythms from the AV connection. If the pacemaker is in the atrioventricular ( atrioventricular node) node, then the ventricles are excited as usual (from top to bottom), and the atria - retrograde (i.e. from bottom to top).

At the same time, on the ECG:

• P waves may be absent because they are superimposed on normal QRS complexes,
• P waves can be negative, located after the QRS complex.

Rhythm from the AV junction, superimposition of the P wave on the QRS complex.

Rhythm from the AV junction, the P wave is located after the QRS complex.

Heart rate with a rhythm from the AV junction is less than sinus rhythm and is approximately 40-60 beats per minute.

Ventricular, or IDIOVENTRICULAR, rhythm

In this case, the source of rhythm is the ventricular conduction system.

Excitation spreads through the ventricles in the wrong way and is therefore slower. Features of idioventricular rhythm:

• QRS complexes are widened and deformed (they look “scary”). Normally, the duration of the QRS complex is 0.06-0.10 s, therefore, with this rhythm, the QRS exceeds 0.12 s.
• There is no pattern between QRS complexes and P waves because the AV junction does not release impulses from the ventricles, and the atria can be excited from the sinus node, as normal.
• Heart rate less than 40 beats per minute.

Idioventricular rhythm. The P wave is not associated with the QRS complex.

d. conductivity assessment.
To properly account for conductivity, the recording speed is taken into account.

To assess conductivity, measure:

• P wave duration (reflects the speed of impulse transmission through the atria),normal up to 0.1 s.
• duration of the P - Q interval (reflects the speed of impulse conduction from the atria to the ventricular myocardium); interval P - Q = (wave P) + (segment P - Q). Fine 0.12-0.2 s .
• duration of the QRS complex (reflects the spread of excitation through the ventricles). Normally 0.06-0.1 s.
• interval of internal deviation in leads V1 and V6. This is the time between the onset of the QRS complex and the R wave. Normally in V1 up to 0.03 s and in V6 up to 0.05 s. Used mainly to recognize bundle branch blocks and to determine the source of excitation in the ventricles in the case of ventricular extrasystole(extraordinary contraction of the heart).

Measuring the internal deviation interval.

3) Determination of the electrical axis of the heart.

4) Analysis of the atrial P wave.

• Normally, in leads I, II, aVF, V2 - V6, the P wavealways positive.
• In leads III, aVL, V1, the P wave can be positive or biphasic (part of the wave is positive, part is negative).
• In lead aVR, the P wave is always negative.
• Normally, the duration of the P wave does not exceed0.1 s, and its amplitude is 1.5 - 2.5 mm.

Pathological deviations of the P wave:

• Pointed high P waves of normal duration in leads II, III, aVF are characteristic of right atrial hypertrophy, for example, with “pulmonary heart”.
• Split with 2 apexes, widened P wave in leads I, aVL, V5, V6 is characteristic ofleft atrial hypertrophy, for example, with mitral valve defects.

Formation of the P wave (P-pulmonale) with hypertrophy of the right atrium.

Formation of the P wave (P-mitrale) with left atrial hypertrophy.

4) P-Q interval analysis:

fine 0.12-0.20 s.

An increase in this interval occurs when the conduction of impulses through the atrioventricular node is impaired ( atrioventricular block, AV block).

There are 3 degrees of AV block:

• I degree - the P-Q interval is increased, but each P wave has its own QRS complex ( no loss of complexes).
• II degree - QRS complexes partially fall out, i.e. Not all P waves have their own QRS complex.
• III degree - complete blockade of conduction in the AV node. The atria and ventricles contract at their own rhythm, independently of each other. Those. idioventricular rhythm occurs.

5) Analysis of the ventricular QRST complex:

1. QRS complex analysis.

   The maximum duration of the ventricular complex is 0.07-0.09 s(up to 0.10 s).

   The duration increases with any bundle branch block.

   Normally, the Q wave can be recorded in all standard and enhanced limb leads, as well as in V4-V6.

   The amplitude of the Q wave normally does not exceed 1/4 R wave height, and the duration is 0.03 s.

   In lead aVR, there is normally a deep and wide Q wave and even a QS complex.

   The R wave, like the Q wave, can be recorded in all standard and enhanced limb leads.

   From V1 to V4, the amplitude increases (in this case, the r wave of V1 may be absent), and then decreases in V5 and V6.

   The S wave can have very different amplitudes, but usually no more than 20 mm.

   The S wave decreases from V1 to V4, and may even be absent in V5-V6.

   In lead V3 (or between V2 - V4) “ transition zone” (equality of R and S waves).

2. RS - T segment analysis

   The S-T segment (RS-T) is a segment from the end of the QRS complex to the beginning of the T wave. - - The S-T segment is especially carefully analyzed in case of coronary artery disease, since it reflects the lack of oxygen (ischemia) in the myocardium.

   Normally, the S-T segment is located in the limb leads on the isoline ( ± 0.5 mm).

   In leads V1-V3, the S-T segment may shift upward (no more than 2 mm), and in leads V4-V6 - downward (no more than 0.5 mm).

   The point at which the QRS complex transitions to the S-T segment is called the point j(from the word junction - connection).

   The degree of deviation of point j from the isoline is used, for example, to diagnose myocardial ischemia.

3. T wave analysis.

   The T wave reflects the process of repolarization of the ventricular myocardium.

   In most leads where a high R is recorded, the T wave is also positive.

   Normally, the T wave is always positive in I, II, aVF, V2-V6, with T I > T III, and T V6 > T V1.

   In aVR the T wave is always negative.

4. Q-T interval analysis.

   The Q-T interval is called electrical ventricular systole, because at this time all parts of the ventricles of the heart are excited.

   Sometimes after the T wave there is a small U wave, which is formed due to short-term increased excitability of the ventricular myocardium after their repolarization.

6) Electrocardiographic report.
Should include:

1. Source of rhythm (sinus or not).
2. Regularity of rhythm (correct or not). Usually sinus rhythm is normal, although respiratory arrhythmia is possible.
3. Position of the electrical axis of the heart.
4. Presence of 4 syndromes:
   • rhythm disturbance
   • conduction disturbance
   • hypertrophy and/or overload of the ventricles and atria
   • myocardial damage (ischemia, dystrophy, necrosis, scars)

ECG interference

Due to frequent questions in the comments about the type of ECG, I’ll tell you about interference which may appear on the electrocardiogram:

Three types of ECG interference(explained below).

Interference on an ECG in the lexicon of health workers is called tip-off:
a) inrush currents: network pickup in the form of regular oscillations with a frequency of 50 Hz, corresponding to the frequency of alternating electric current in the outlet.
b) " swimming"(drift) of the isoline due to poor contact of the electrode with the skin;
c) interference caused by muscle tremors(irregular frequent vibrations are visible).

ECG analysis algorithm: determination method and basic standards

Considering that there are a lot of violations, we will focus only on the most basic ones, but first you need to learn to distinguish sinus rhythm from non-sinus rhythm. To do this you need to remember, write down (who needs it) signs of sinus rhythm.

• Presence in leads II (and usually aVF) positive, identical according to the shape of the P waves, located at the same distance from the QRS complex in all complexes (heartbeats).
• Heart rate (I’ll tell you how to determine it later) from 60 to 100 per minute (less is already bradycardia, more - tachycardia.).
• The difference between the largest and smallest RR intervals (more on intervals later) should not exceed 10%. (however, this rule only applies if the heart rate is more than 60 per minute, that is, if there is no sinus bradycardia)

As you may have guessed, to understand rhythm you need to talk about how to determine the frequency of the rhythm and intervals.

ECG INTERVALS (now we are only interested in R.R.)

This diagram more than clearly demonstrates how to measure the RR interval.

Note: Intervals are measured in milliseconds, for example: 750 ms or 0.75 s, but we will use a simpler method.

Knowing how to measure the RR interval, we can determine the heart rate (HR)

DETERMINATION OF HEART RATE

Regardless of the type of ECG device, the recording always contains small cells 1 × 1 mm and large 5 × 5 mm, the speed of the tape is also indicated (this is important!), usually 50 mm/s. or 25 mm/s.

At belt speed 50 mm/s:

Heart rate = 600 / (number of large squares between two RRs (interval RR); or heart rate = 3000/ (number of small squares).

At belt speed 25 mm/s:

Heart rate = 300 / (number of large squares between two RRs (interval RR); or 1500/ (number of small squares).

Here it would be appropriate to give a little additional information about the ECG waves.

Each wave on an ECG has two characteristics: amplitude and duration.

Amplitude expressed in mV (millivolts), usually one mV corresponds to ten mm or 10 small cells.

Duration expressed in seconds (less often milliseconds), so one cell in a standard ECG recording (tape speed 50 mm/s) is equal to 0.02 s. When recording at a speed of 25 mm/s, one small cell is equal to 0.04 s.

Let's try to use this formula together (by the way, it was not taken from our heads, but is derived mathematically, but let's not talk about that)

EXAMPLE ECG No. 1

CALCULATION: the speed of the tape is 50 mm/s, choose any lead where there are high R waves, let it be II.

We take the first RR - it is equal to almost 9 large cells, which means: heart rate = 600/9 = 66 beats. per minute

Or, RR is equal to 45 small cells, then: heart rate = 3000/45 = 66 beats. per minute That's all.

As you can see, the numbers almost coincided with those calculated by the computer; this technique is used to determine heart rate “by eye.” In practice, it is convenient to use special cardiac rulers.

But let's make it more difficult.

Example ECG No. 2

As you can see, the rhythm frequency varies from 63 to 84, what should you do in this case?

The easiest way is to take 3-4 intervals and find the arithmetic mean, that is: (59+64+80+84)/4 = 72 beats. per minute

How to determine sinus rhythm?

We digressed a little from the plan, if you remember, one of the signs of sinus rhythm is:

The presence in leads II and aVF of predominantly positive, identically shaped P waves, located at the same distance from the QRS in all complexes (heartbeats).

Let's look at an example:

Example ECG No. 3

As you can see, in leads II, AVF, identical in shape, positive P waves are quite clearly defined.
They are also at the same distance from the ventricular QRS complex (in this case there is no S wave, therefore qR) are marked with black markers. The first condition is met.

Second condition: Heart rate = 60-100 per minute. As you can see, the frequency here is about 68-70 rpm. Done

Third condition the difference between the two RRs does not exceed 10%. What does it mean? , on it the rhythm frequency varied from 59 to 84, that is, the difference between two numbers (84-59) = 25. In order to understand what this difference looks like in percentage, you need to create a proportion: (100 × 25/84) = 29% (direct proportion, school program), which means the third condition is not met and the rhythm on ECG No. 2 is not sinus. When all conditions are met, but the difference in RR exceeds 10%, this is called

On our ECG No. 3, the difference is only 70-65 = 5, which corresponds to 8% (although this is visible without calculations or ... will be visible to you over time). The third condition is met. In any case, you can't really go wrong if you ignore this difference. This is not the biggest mistake.

Thus, ECG 3 shows sinus rhythm.

In general, we have covered enough here for you to start trying to determine the rhythm yourself, at the “sinus - not sinus” level.
Let's move on to training.

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Almost every person who has undergone an electrocardiogram is interested in the meaning of different teeth and the terms written by the diagnostician. Although only a cardiologist can give a full interpretation of an ECG, everyone can easily figure out whether their heart cardiogram is good or if there are some abnormalities.

Indications for an ECG

A non-invasive study - an electrocardiogram - is performed in the following cases:

• The patient complains of high blood pressure, chest pain and other symptoms indicating cardiac pathology;
• Deterioration in the well-being of a patient with a previously diagnosed cardiovascular disease;
• Abnormalities in laboratory blood tests - increased cholesterol, prothrombin;
• In preparation for surgery;
• Detection of endocrine pathology, diseases of the nervous system;
• After severe infections with a high risk of heart complications;
• For prophylactic purposes in pregnant women;
• Examination of the health status of drivers, pilots, etc.

Decoding ECG - numbers and Latin letters

A full-scale interpretation of the cardiac cardiogram includes an assessment of the heart rhythm, the functioning of the conduction system and the condition of the myocardium. For this, the following leads are used (electrodes are installed in a certain order on the chest and limbs):

• Standard: I - left/right wrist on the hands, II - right wrist and ankle area on the left leg, III - left ankle and wrist.
• Strengthened: aVR - right wrist and combined left upper/lower limbs, aVL - left wrist and combined left ankle and right wrist, aVF - left ankle area and combined potential of both wrists.
• Thoracic (potential difference between the electrode with a suction cup located on the chest and the combined potentials of all extremities): V1 - electrode in the IV intercostal space along the right border of the sternum, V2 - in the IV intercostal space to the left of the sternum, V3 - on the IV rib along the left-sided parasternal line, V4 - V intercostal space along the left midclavicular line, V5 - V intercostal space along the anterior axillary line on the left, V6 - V intercostal space along the mid-axillary line on the left.

Additional pectorals - located symmetrically to the left pectoralis with additional V7-9.

One cardiac cycle on the ECG is represented by the PQRST graph, which records electrical impulses in the heart:

• P wave - displays atrial excitation;
• QRS complex: Q wave - the initial phase of depolarization (excitation) of the ventricles, R wave - the actual process of ventricular excitation, S wave - the end of the depolarization process;
• T wave - characterizes the extinction of electrical impulses in the ventricles;
• ST segment - describes the complete restoration of the original state of the myocardium.

When deciphering ECG indicators, the height of the teeth and their location relative to the isoline, as well as the width of the intervals between them, are important.

Sometimes a U pulse is recorded behind the T wave, indicating the parameters of the electrical charge carried away with the blood.

Interpretation of ECG indicators - the norm in adults

On the electrocardiogram, the width (horizontal distance) of the teeth - the duration of the period of excitation of relaxation - is measured in seconds, the height in leads I-III - the amplitude of the electrical impulse - in mm. A normal cardiogram in an adult looks like this:

• Heart rate - normal heart rate is within 60-100/min. The distance from the tops of adjacent R waves is measured.
• EOS - the electrical axis of the heart is considered to be the direction of the total angle of the electrical force vector. The normal value is 40-70º. Deviations indicate rotation of the heart around its own axis.
• The P wave is positive (directed upward), negative only in lead aVR. Width (duration of excitation) - 0.7 - 0.11 s, vertical size - 0.5 - 2.0 mm.
• PQ interval - horizontal distance 0.12 - 0.20 s.
• The Q wave is negative (below the isoline). Duration 0.03 s, negative height value 0.36 - 0.61 mm (equal to ¼ of the vertical size of the R wave).
• The R wave is positive. What matters is its height - 5.5 -11.5 mm.
• S wave - negative height 1.5-1.7 mm.
• QRS complex - horizontal distance 0.6 - 0.12 s, total amplitude 0 - 3 mm.
• The T wave is asymmetrical. Positive height 1.2 - 3.0 mm (equal to 1/8 - 2/3 of the R wave, negative in the aVR lead), duration 0.12 - 0.18 s (longer than the duration of the QRS complex).
• ST segment - passes at the level of the isoline, length 0.5 -1.0 s.
• U wave - height indicator 2.5 mm, duration 0.25 s.

Abbreviated results of ECG interpretation in adults and the norm in the table:

During normal research (recording speed - 50 mm/sec), ECG decoding in adults is carried out according to the following calculations: 1 mm on paper when calculating the duration of intervals corresponds to 0.02 sec.

A positive P wave (standard leads) followed by a normal QRS complex means normal sinus rhythm.

Normal ECG in children, interpretation

Cardiogram parameters in children are somewhat different from those in adults and vary depending on age. Interpretation of the ECG of the heart in children, normal:

• Heart rate: newborns - 140 - 160, by 1 year - 120 - 125, by 3 years - 105 -110, by 10 years - 80 - 85, after 12 years - 70 - 75 per minute;
• EOS - corresponds to adult indicators;
• sinus rhythm;
• tooth P - does not exceed 0.1 mm in height;
• length of the QRS complex (often not particularly informative in diagnosis) - 0.6 - 0.1 s;
• PQ interval - less than or equal to 0.2 s;
• Q wave - unstable parameters, negative values ​​in lead III are acceptable;
• P wave - always above the isoline (positive), the height in one lead may fluctuate;
• S wave - negative indicators of variable value;
• QT - no more than 0.4 s;
• The duration of the QRS and the T wave are equal, 0.35 - 0.40.

Example of an ECG with rhythm disturbance

Based on deviations in the cardiogram, a qualified cardiologist can not only diagnose the nature of the heart disease, but also record the location of the pathological focus.

Arrhythmias

The following cardiac rhythm disorders are distinguished:

1. Sinus arrhythmia - the length of the RR intervals fluctuates with a difference of up to 10%. It is not considered a pathology in children and young people.
2. Sinus bradycardia is a pathological decrease in the frequency of contractions to 60 per minute or less. The P wave is normal, PQ from 12 s.
3. Tachycardia - heart rate 100 - 180 per minute. In teenagers - up to 200 per minute. The rhythm is correct. With sinus tachycardia, the P wave is slightly higher than normal, with ventricular tachycardia, the QRS length indicator is above 0.12 s.
4. Extrasystoles are extraordinary contractions of the heart. Single ones on a regular ECG (on a 24-hour Holter - no more than 200 per day) are considered functional and do not require treatment.
5. Paroxysmal tachycardia is a paroxysmal (several minutes or days) increase in heart rate up to 150-220 per minute. It is characteristic (only during an attack) that the P wave merges with the QRS. The distance from the R wave to the P height of the next contraction is less than 0.09 s.
6. Atrial fibrillation is an irregular contraction of the atria with a frequency of 350-700 per minute, and of the ventricles - 100-180 per minute. There is no P wave, there are small-to-large undulating oscillations along the entire isoline.
7. Atrial flutter - up to 250-350 atrial contractions per minute and regular slow ventricular contractions. The rhythm may be correct; the ECG shows sawtooth atrial waves, especially pronounced in standard leads II - III and thoracic leads V1.

Deviation of EOS position

A change in the total EOS vector to the right (more than 90º), a higher value of the height of the S wave compared to the R wave indicate pathology of the right ventricle and His bundle block.

When the EOS is shifted to the left (30-90º) and there is a pathological ratio of the heights of the S and R waves, left ventricular hypertrophy and blockade of the bundle branch of His are diagnosed. Deviation of EOS indicates a heart attack, pulmonary edema, COPD, but it can also be normal.

Violation of the conduction system

The following pathologies are most often recorded:

• 1st degree of atrioventricular (AV) block - PQ distance more than 0.20 s. After each P, QRS naturally follows;
• Atrioventricular block, stage 2. - a gradually lengthening PQ throughout the ECG sometimes displaces the QRS complex (Mobitz 1 type deviation) or a complete loss of QRS is recorded against the background of a PQ of equal length (Mobitz 2);
• Complete block of the AV node - the atrial heart rate is higher than the ventricular heart rate. PP and RR are the same, PQ are different lengths.

Selected heart diseases

The results of ECG interpretation can provide information not only about the heart disease that has occurred, but also about the pathology of other organs:

1. Cardiomyopathy - atrial hypertrophy (usually the left one), low-amplitude waves, partial blockade of the His, atrial fibrillation or extrasystoles.
2. Mitral stenosis - the left atrium and right ventricle are enlarged, the EOS is deviated to the right, often atrial fibrillation.
3. Mitral valve prolapse - flattened/negative T wave, some QT prolongation, depressed ST segment. Various rhythm disturbances are possible.
4. Chronic pulmonary obstruction - EOS is to the right of normal, low-amplitude waves, AV block.
5. Damage to the central nervous system (including subarachnoid hemorrhage) - pathological Q, wide and high-amplitude (negative or positive) T wave, pronounced U, long duration of QT rhythm disturbance.
6. Hypothyroidism - long PQ, low QRS, flat T wave, bradycardia.

Quite often, an ECG is performed to diagnose myocardial infarction. At the same time, each of its stages corresponds to characteristic changes in the cardiogram:

• ischemic stage - a pointed T with a sharp apex is recorded 30 minutes before the onset of necrosis of the heart muscle;
• stage of damage (changes are recorded in the first hours to 3 days) - ST in the form of a dome above the isoline merges with the T wave, shallow Q and high R;
• acute stage (1-3 weeks) - the worst cardiogram of the heart during a heart attack - preservation of the dome-shaped ST and the transition of the T wave to negative values, decreased height of R, pathological Q;
• subacute stage (up to 3 months) - comparison of ST with the isoline, preservation of pathological Q and T;
• stage of scarring (several years) - pathological Q, negative R, smoothed T wave gradually comes to normal values.

There is no need to sound the alarm if you find pathological changes in the ECG issued to you. It should be remembered that some deviations from the norm occur in healthy people.

If an electrocardiogram reveals any pathological processes in the heart, you will definitely be scheduled for a consultation with a qualified cardiologist.

Pathology of the cardiovascular system is one of the most common problems that affects people of all ages. Timely treatment and diagnosis of the circulatory system can significantly reduce the risk of developing dangerous diseases.

Today, the most effective and easily accessible method for studying heart function is an electrocardiogram.

When studying the results of a patient's examination, Doctors pay attention to such components of the ECG as:

• Teeth;
• Intervals;
• Segments.

Not only their presence or absence is assessed, but also their height, duration, location, direction and sequence.

There are strict normal parameters for each line on the ECG tape, the slightest deviation from which may indicate violations in the work of the heart.

Cardiogram analysis

The entire set of ECG lines is examined and measured mathematically, after which the doctor can determine some parameters of the work of the heart muscle and its conduction system: heart rhythm, heart rate, pacemaker, conductivity, electrical axis of the heart.

Today, all these indicators are studied by high-precision electrocardiographs.

Sinus rhythm of the heart

This is a parameter that reflects the rhythm of heart contractions that occur under the influence of the sinus node (normal). It shows the coherence of the work of all parts of the heart, the sequence of processes of tension and relaxation of the heart muscle.

The rhythm is very easily identified by the tallest R waves: if the distance between them is the same throughout the entire recording or deviates by no more than 10%, then the patient does not suffer from arrhythmia.

Heart rate

The number of beats per minute can be determined not only by counting the pulse, but also by ECG. To do this, you need to know the speed at which the ECG was recorded (usually 25, 50 or 100 mm/s), as well as the distance between the highest teeth (from one vertex to another).

Multiplying the recording duration of one mm by length of segment R-R, you can get the heart rate. Normally, its indicators range from 60 to 80 beats per minute.

Excitation source

The autonomic nervous system of the heart is designed in such a way that the contraction process depends on the accumulation of nerve cells in one of the zones of the heart. Normally, this is the sinus node, impulses from which disperse throughout the nervous system of the heart.

In some cases, the role of pacemaker can be taken over by other nodes (atrial, ventricular, atrioventricular). This can be determined by examining the P wave is inconspicuous, located just above the isoline.

You can read detailed and comprehensive information about the symptoms of cardiac cardiosclerosis.

Conductivity

This is a criterion showing the process of impulse transmission. Normally, impulses are transmitted sequentially from one pacemaker to another, without changing the order.

Electric axis

An indicator based on the process of ventricular excitation. Mathematical analysis of Q, R, S waves in leads I and III allows one to calculate a certain resulting vector of their excitation. This is necessary to establish the functioning of the branches of the His bundle.

The resulting angle of inclination of the heart axis is estimated by its value: 50-70° normal, 70-90° deviation to the right, 50-0° deviation to the left.

In cases where there is a tilt of more than 90° or more than -30°, there is a serious disruption of the His bundle.

Teeth, segments and intervals

Waves are sections of the ECG lying above the isoline, their meaning is as follows:

• P– reflects the processes of contraction and relaxation of the atria.
• Q, S– reflect the processes of excitation of the interventricular septum.
• R– the process of excitation of the ventricles.
• T- the process of relaxation of the ventricles.

Intervals are ECG sections lying on the isoline.

• PQ– reflects the time of impulse propagation from the atria to the ventricles.

Segments are sections of an ECG, including an interval and a wave.

• QRST– duration of ventricular contraction.
• ST– time of complete excitation of the ventricles.
• TP– time of electrical diastole of the heart.

Normal for men and women

Interpretation of the ECG of the heart and normal indicators in adults are presented in this table:

Healthy Childhood Outcomes

Interpretation of the results of ECG measurements in children and their norm in this table:

Dangerous diagnoses

What dangerous conditions can be determined by ECG readings during interpretation?

Extrasystole

This phenomenon characterized by abnormal heart rhythm. The person feels a temporary increase in contraction frequency followed by a pause. It is associated with the activation of other pacemakers, which, along with the sinus node, send an additional volley of impulses, which leads to an extraordinary contraction.

If extrasystoles appear no more than 5 times per hour, then they cannot cause significant harm to health.

Arrhythmia

Characterized by change in sinus rhythm periodicity when pulses arrive at different frequencies. Only 30% of such arrhythmias require treatment, because can provoke more serious diseases.

In other cases, this may be a manifestation of physical activity, changes in hormonal levels, the result of a previous fever and does not threaten health.

Bradycardia

Occurs when the sinus node is weakened, unable to generate impulses with the proper frequency, as a result of which the heart rate slows down, up to 30-45 beats per minute.

Tachycardia

The opposite phenomenon, characterized by an increase in heart rate more than 90 beats per minute. In some cases, temporary tachycardia occurs under the influence of severe physical exertion and emotional stress, as well as during illnesses associated with increased temperature.

Conduction disturbance

In addition to the sinus node, there are other underlying pacemakers of the second and third orders. Normally, they conduct impulses from the first-order pacemaker. But if their functions weaken, a person may feel weakness, dizziness caused by depression of the heart.

It is also possible to lower blood pressure, because... the ventricles will contract less frequently or arrhythmically.

Many factors can lead to disruptions in the functioning of the heart muscle itself. Tumors develop, muscle nutrition is disrupted, and depolarization processes are disrupted. Most of these pathologies require serious treatment.

Why there might be differences in performance

In some cases, when re-analyzing the ECG, deviations from previously obtained results are revealed. With what it can be connected?

• Different times of day. Typically, an ECG is recommended to be done in the morning or afternoon, when the body has not yet been exposed to stress factors.
• Loads. It is very important that the patient is calm when recording an ECG. The release of hormones can increase heart rate and distort indicators. In addition, it is also not recommended to engage in heavy physical labor before the examination.
• Eating. Digestive processes affect blood circulation, and alcohol, tobacco and caffeine can affect heart rate and blood pressure.
• Electrodes. Incorrect application or accidental displacement can seriously change the indicators. Therefore, it is important not to move during recording and to degrease the skin in the area where the electrodes are applied (the use of creams and other skin products before the examination is highly undesirable).
• Background. Sometimes extraneous devices can affect the operation of the electrocardiograph.

Additional examination techniques

Holter

Method long-term study of heart function, possible thanks to a portable compact tape recorder that is capable of recording results on magnetic film. The method is especially good when it is necessary to study periodically occurring pathologies, their frequency and time of occurrence.

Treadmill

Unlike a conventional ECG, which is recorded at rest, this method is based on the analysis of the results after physical activity. Most often, this is used to assess the risk of possible pathologies not detected on a standard ECG, as well as when prescribing a course of rehabilitation for patients who have suffered a heart attack.

Phonocardiography

Allows analyze heart sounds and murmurs. Their duration, frequency and time of occurrence correlate with the phases of cardiac activity, which makes it possible to assess the functioning of the valves and the risks of developing endo- and rheumatic carditis.

A standard ECG is a graphical representation of the work of all parts of the heart. Many factors can affect its accuracy, so the doctor's recommendations should be followed.

The examination reveals most pathologies of the cardiovascular system, but additional tests may be required for an accurate diagnosis.

Finally, we suggest watching a video course on decoding “An ECG can be done by everyone”:

Decoding an ECG is the job of a knowledgeable doctor. This method of functional diagnostics evaluates:

• heart rate - the state of the generators of electrical impulses and the state of the heart system conducting these impulses
• condition of the heart muscle itself (myocardium), the presence or absence of inflammation, damage, thickening, oxygen starvation, electrolyte imbalance

However, modern patients often have access to their medical documents, in particular, to electrocardiography films on which medical reports are written. With their diversity, these records can reach even the most balanced but ignorant person. After all, the patient often does not know for certain how dangerous to life and health is what is written on the back of the ECG film by the hand of a functional diagnostician, and there are still several days before an appointment with a therapist or cardiologist.

To reduce the intensity of passions, we immediately warn readers that with not a single serious diagnosis (myocardial infarction, acute rhythm disturbances), a functional diagnostician will not let a patient leave the office, but, at a minimum, will send him for a consultation with a fellow specialist right there. About the rest of the “open secrets” in this article. In all unclear cases of pathological changes in the ECG, ECG monitoring, 24-hour monitoring (Holter), ECHO cardioscopy (ultrasound of the heart) and stress tests (treadmill, bicycle ergometry) are prescribed.

Numbers and Latin letters in ECG interpretation

PQ- (0.12-0.2 s) – atrioventricular conduction time. Most often it lengthens against the background of AV blockade. Shortened in CLC and WPW syndromes.

P – (0.1s) height 0.25-2.5 mm describes atrial contractions. May indicate their hypertrophy.

QRS – (0.06-0.1s) -ventricular complex

QT – (no more than 0.45 s) lengthens with oxygen starvation (myocardial ischemia, infarction) and the threat of rhythm disturbances.

RR - the distance between the apices of the ventricular complexes reflects the regularity of heart contractions and makes it possible to calculate heart rate.

The interpretation of the ECG in children is presented in Fig. 3

Heart Rate Description Options

Sinus rhythm

This is the most common inscription found on an ECG. And, if nothing else is added and the frequency (HR) is indicated from 60 to 90 beats per minute (for example, HR 68`) - this is the best option, indicating that the heart works like a clock. This is the rhythm set by the sinus node (the main pacemaker that generates electrical impulses that cause the heart to contract). At the same time, sinus rhythm implies well-being, both in the state of this node and the health of the conduction system of the heart. The absence of other records denies pathological changes in the heart muscle and means that the ECG is normal. In addition to sinus rhythm, there may be atrial, atrioventricular or ventricular, indicating that the rhythm is set by cells in these parts of the heart and is considered pathological.

Sinus arrhythmia

This is a normal variant in young people and children. This is a rhythm in which impulses leave the sinus node, but the intervals between heart contractions are different. This may be due to physiological changes (respiratory arrhythmia, when heart contractions slow down during exhalation). Approximately 30% of sinus arrhythmias require observation by a cardiologist, as they are at risk of developing more serious rhythm disturbances. These are arrhythmias after rheumatic fever. Against the background of myocarditis or after it, against the background of infectious diseases, heart defects and in persons with a family history of arrhythmias.

Sinus bradycardia

These are rhythmic contractions of the heart with a frequency of less than 50 per minute. In healthy people, bradycardia occurs, for example, during sleep. Bradycardia also often occurs in professional athletes. Pathological bradycardia may indicate sick sinus syndrome. In this case, bradycardia is more pronounced (heart rate from 45 to 35 beats per minute on average) and is observed at any time of the day. When bradycardia causes pauses in heart contractions of up to 3 seconds during the day and about 5 seconds at night, leads to disturbances in the supply of oxygen to tissues and is manifested, for example, by fainting, an operation is indicated to install a cardiac pacemaker, which replaces the sinus node, imposing a normal rhythm of contractions on the heart.

Sinus tachycardia

Heart rate more than 90 per minute is divided into physiological and pathological. In healthy people, sinus tachycardia is accompanied by physical and emotional stress, drinking coffee, sometimes strong tea or alcohol (especially energy drinks). It is short-lived and after an episode of tachycardia, the heart rate returns to normal within a short period of time after stopping the load. With pathological tachycardia, heartbeats bother the patient at rest. Its causes include fever, infections, blood loss, dehydration, anemia,. The underlying disease is treated. Sinus tachycardia is stopped only in case of a heart attack or acute coronary syndrome.

Extarsystole

These are rhythm disturbances in which foci outside the sinus rhythm give extraordinary cardiac contractions, after which there is a pause of twice the length, called compensatory. In general, the patient perceives heartbeats as uneven, rapid or slow, and sometimes chaotic. The most worrying thing is the dips in heart rate. May occur in the form of tremors, tingling, feelings of fear and emptiness in the stomach.

Not all extrasystoles are dangerous to health. Most of them do not lead to significant circulatory disorders and do not threaten either life or health. They can be functional (against the background of panic attacks, cardioneurosis, hormonal imbalances), organic (with ischemic heart disease, heart defects, myocardial dystrophy or cardiopathy, myocarditis). Intoxication and heart surgery can also lead to them. Depending on the place of occurrence, extrasystoles are divided into atrial, ventricular and anthrioventricular (arising in the node at the border between the atria and ventricles).

• Single extrasystoles most often rare (less than 5 per hour). They are usually functional and do not interfere with normal blood supply.
• Paired extrasystoles two each accompany a certain number of normal contractions. Such rhythm disturbances often indicate pathology and require further examination (Holter monitoring).
• Allorhythmias are more complex types of extrasystoles. If every second contraction is an extrasystole, this is bigymenia, if every third contraction is trigymenia, every fourth is quadrigymenia.

It is customary to divide ventricular extrasystoles into five classes (according to Lown). They are assessed during daily ECG monitoring, since the readings of a regular ECG in a few minutes may not show anything.

• Class 1 - single rare extrasystoles with a frequency of up to 60 per hour, emanating from one focus (monotopic)
• 2 – frequent monotopic more than 5 per minute
• 3 – frequent polymorphic (of different shapes) polytopic (from different foci)
• 4a – paired, 4b – group (trigymenia), episodes of paroxysmal tachycardia
• 5 – early extrasystoles

The higher the class, the more serious the violations, although today even classes 3 and 4 do not always require drug treatment. In general, if there are less than 200 ventricular extrasystoles per day, they should be classified as functional and not worry about them. For more frequent cases, ECHO CS is indicated, and sometimes cardiac MRI is indicated. It is not the extrasystole that is treated, but the disease that leads to it.

Paroxysmal tachycardia

In general, a paroxysm is an attack. A paroxysmal increase in rhythm can last from several minutes to several days. In this case, the intervals between heart contractions will be the same, and the rhythm will increase over 100 per minute (on average from 120 to 250). There are supraventricular and ventricular forms of tachycardia. This pathology is based on abnormal circulation of electrical impulses in the conduction system of the heart. This pathology can be treated. Home remedies to relieve an attack:

• holding your breath
• increased forced cough
• immersing face in cold water

WPW syndrome

Wolff-Parkinson-White syndrome is a type of paroxysmal supraventricular tachycardia. Named after the authors who described it. The appearance of tachycardia is based on the presence of an additional nerve bundle between the atria and ventricles, through which a faster impulse passes than from the main pacemaker.

As a result, an extraordinary contraction of the heart muscle occurs. The syndrome requires conservative or surgical treatment (in case of ineffectiveness or intolerance of antiarrhythmic tablets, during episodes of atrial fibrillation, and with concomitant heart defects).

CLC – syndrome (Clerk-Levi-Christesco)

is similar in mechanism to WPW and is characterized by earlier excitation of the ventricles than normal due to an additional bundle along which the nerve impulse travels. The congenital syndrome is manifested by attacks of rapid heartbeat.

Atrial fibrillation

It can be in the form of an attack or a permanent form. It manifests itself in the form of atrial flutter or fibrillation.

Atrial fibrillation

Atrial fibrillation

When flickering, the heart contracts completely irregularly (the intervals between contractions of very different durations). This is explained by the fact that the rhythm is not set by the sinus node, but by other cells of the atria.

The resulting frequency is from 350 to 700 beats per minute. There is simply no full contraction of the atria; contracting muscle fibers do not effectively fill the ventricles with blood.

As a result, the heart’s output of blood deteriorates and organs and tissues suffer from oxygen starvation. Another name for atrial fibrillation is atrial fibrillation. Not all atrial contractions reach the ventricles of the heart, so the heart rate (and pulse) will be either below normal (bradysystole with a frequency of less than 60), or normal (normosystole from 60 to 90), or above normal (tachysystole more than 90 beats per minute ).

An attack of atrial fibrillation is difficult to miss.

• It usually starts with a strong beat of the heart.
• It develops as a series of absolutely irregular heartbeats with a high or normal frequency.
• The condition is accompanied by weakness, sweating, dizziness.
• The fear of death is very pronounced.
• There may be shortness of breath, general agitation.
• Sometimes observed.
• The attack ends with normalization of the rhythm and the urge to urinate, during which a large amount of urine is released.

To stop an attack, they use reflex methods, drugs in the form of tablets or injections, or resort to cardioversion (stimulating the heart with an electric defibrillator). If an attack of atrial fibrillation is not eliminated within two days, the risks of thrombotic complications (pulmonary embolism, stroke) increase.

With a constant form of heartbeat flicker (when the rhythm is not restored either against the background of drugs or against the background of electrical stimulation of the heart), they become a more familiar companion to patients and are felt only during tachysystole (rapid, irregular heartbeats). The main task when detecting signs of tachysystole of a permanent form of atrial fibrillation on the ECG is to slow down the rhythm to normosystole without trying to make it rhythmic.

Examples of recordings on ECG films:

• atrial fibrillation, tachysystolic variant, heart rate 160 b'.
• Atrial fibrillation, normosystolic variant, heart rate 64 b'.

Atrial fibrillation can develop in the course of coronary heart disease, against the background of thyrotoxicosis, organic heart defects, diabetes mellitus, sick sinus syndrome, and intoxication (most often with alcohol).

Atrial flutter

These are frequent (more than 200 per minute) regular contractions of the atria and equally regular, but less frequent contractions of the ventricles. In general, flutter is more common in the acute form and is better tolerated than flicker, since circulatory disorders are less pronounced. Fluttering develops when:

• organic heart diseases (cardiomyopathies, heart failure)
• after heart surgery
• against the background of obstructive pulmonary diseases
• in healthy people it almost never occurs

Clinically, flutter is manifested by rapid rhythmic heartbeat and pulse, swelling of the neck veins, shortness of breath, sweating and weakness.

Conduction disorders

Normally, having formed in the sinus node, electrical excitation travels through the conduction system, experiencing a physiological delay of a split second in the atrioventricular node. On its way, the impulse stimulates the atria and ventricles, which pump blood, to contract. If in any part of the conduction system the impulse is delayed longer than the prescribed time, then excitation to the underlying sections will come later, and, therefore, the normal pumping work of the heart muscle will be disrupted. Conduction disturbances are called blockades. They can occur as functional disorders, but more often they are the result of drug or alcohol intoxication and organic heart disease. Depending on the level at which they arise, several types are distinguished.

Sinoatrial blockade

When the exit of an impulse from the sinus node is difficult. In essence, this leads to sick sinus syndrome, slowing of contractions to severe bradycardia, impaired blood supply to the periphery, shortness of breath, weakness, dizziness and loss of consciousness. The second degree of this blockade is called Samoilov-Wenckebach syndrome.

Atrioventricular block (AV block)

This is a delay of excitation in the atrioventricular node longer than the prescribed 0.09 seconds. There are three degrees of this type of blockade. The higher the degree, the less often the ventricles contract, the more severe the circulatory disorders.

• In the first, the delay allows each atrial contraction to maintain an adequate number of ventricular contractions.
• The second degree leaves some of the atrial contractions without ventricular contractions. It is described, depending on the prolongation of the PQ interval and the loss of ventricular complexes, as Mobitz 1, 2 or 3.
• The third degree is also called complete transverse blockade. The atria and ventricles begin to contract without interconnection.

In this case, the ventricles do not stop because they obey the pacemakers from the underlying parts of the heart. If the first degree of blockade may not manifest itself in any way and can be detected only with an ECG, then the second is already characterized by sensations of periodic cardiac arrest, weakness, and fatigue. With complete blockades, brain symptoms are added to the manifestations (dizziness, spots in the eyes). Morgagni-Adams-Stokes attacks may develop (when the ventricles escape from all pacemakers) with loss of consciousness and even convulsions.

Impaired conduction within the ventricles

In the ventricles, the electrical signal propagates to the muscle cells through such elements of the conduction system as the trunk of the His bundle, its legs (left and right) and branches of the legs. Blockades can occur at any of these levels, which is also reflected in the ECG. In this case, instead of being simultaneously covered by excitation, one of the ventricles is delayed, since the signal to it bypasses the blocked area.

In addition to the place of origin, a distinction is made between complete or incomplete blockade, as well as permanent and non-permanent blockade. The causes of intraventricular blocks are similar to other conduction disorders (ischemic heart disease, myocarditis and endocarditis, cardiomyopathies, heart defects, arterial hypertension, fibrosis, heart tumors). Also affected are the use of antiarthmic drugs, an increase in potassium in the blood plasma, acidosis, and oxygen starvation.

• The most common is blockade of the anterosuperior branch of the left bundle branch (ALBBB).
• In second place is right leg block (RBBB). This blockade is usually not accompanied by heart disease.
• Left bundle branch block more typical for myocardial lesions. In this case, complete blockade (PBBB) is worse than incomplete blockade (LBBB). It sometimes has to be distinguished from WPW syndrome.
• Block of the posteroinferior branch of the left bundle branch may occur in persons with a narrow and elongated or deformed chest. Among pathological conditions, it is more typical for overload of the right ventricle (with pulmonary embolism or heart defects).

The clinical picture of blockades at the levels of the His bundle is not expressed. The picture of the underlying cardiac pathology comes first.

• Bailey's syndrome is a two-bundle block (of the right bundle branch and the posterior branch of the left bundle branch).

Myocardial hypertrophy

With chronic overload (pressure, volume), the heart muscle in certain areas begins to thicken, and the chambers of the heart begin to stretch. On the ECG, such changes are usually described as hypertrophy.

• (LVH) – typical for arterial hypertension, cardiomyopathy, and a number of heart defects. But even normally, athletes, obese patients and people engaged in heavy physical labor may experience signs of LVH.
• Right ventricular hypertrophy- an undoubted sign of increased pressure in the pulmonary blood flow system. Chronic cor pulmonale, obstructive pulmonary diseases, cardiac defects (pulmonary stenosis, tetralogy of Fallot, ventricular septal defect) lead to RVH.
• Left atrial hypertrophy (LAH)) – with mitral and aortic stenosis or insufficiency, hypertension, cardiomyopathy, after.
• Right atrial hypertrophy (RAH)– with cor pulmonale, tricuspid valve defects, chest deformities, pulmonary pathologies and pulmonary embolism.
• Indirect signs of ventricular hypertrophy- this is a deviation of the electrical axis of the heart (EOC) to the right or left. The left type of EOS is its deviation to the left, that is, LVH, the right type is RVH.
• Systolic overload- This is also evidence of hypertrophy of the heart. Less commonly, this is evidence of ischemia (in the presence of angina pain).

Changes in myocardial contractility and nutrition

Early ventricular repolarization syndrome

Most often, this is a variant of the norm, especially for athletes and people with congenital high body weight. Sometimes associated with myocardial hypertrophy. Refers to the peculiarities of the passage of electrolytes (potassium) through the membranes of cardiocytes and the characteristics of the proteins from which the membranes are built. It is considered a risk factor for sudden cardiac arrest, but does not provide clinical results and most often remains without consequences.

Moderate or severe diffuse changes in the myocardium

This is evidence of a malnutrition of the myocardium as a result of dystrophy, inflammation () or. Also, reversible diffuse changes accompany disturbances in water and electrolyte balance (with vomiting or diarrhea), taking medications (diuretics), and heavy physical activity.

Nonspecific ST changes

This is a sign of deterioration in myocardial nutrition without severe oxygen starvation, for example, in case of disturbances in the balance of electrolytes or against the background of dyshormonal conditions.

Acute ischemia, ischemic changes, T wave changes, ST depression, low T

This describes reversible changes associated with oxygen starvation of the myocardium (ischemia). This can be either stable angina or unstable, acute coronary syndrome. In addition to the presence of the changes themselves, their location is also described (for example, subendocardial ischemia). A distinctive feature of such changes is their reversibility. In any case, such changes require comparison of this ECG with old films, and if a heart attack is suspected, troponin rapid tests for myocardial damage or coronary angiography. Depending on the type of coronary heart disease, anti-ischemic treatment is selected.

Advanced heart attack

It is usually described:

• by stages: acute (up to 3 days), acute (up to 3 weeks), subacute (up to 3 months), cicatricial (all life after a heart attack)
• by volume: transmural (large focal), subendocardial (small focal)
• by location of heart attacks: there are anterior and anterior septal, basal, lateral, inferior (posterior diaphragmatic), circular apical, posterobasal and right ventricular.

In any case, a heart attack is a reason for immediate hospitalization.

The whole variety of syndromes and specific changes on the ECG, the difference in indicators for adults and children, the abundance of reasons leading to the same type of ECG changes do not allow a non-specialist to interpret even the finished conclusion of a functional diagnostician. It is much wiser, having the ECG result in hand, to visit a cardiologist in a timely manner and receive competent recommendations for further diagnosis or treatment of your problem, significantly reducing the risks of emergency cardiac conditions.