This article presents modern views on ECG diagnostics in pediatrics. The team of authors reviewed some of the most characteristic changes, distinguishing ECG in childhood.
Normal ECG in children it differs from the ECG of adults and has a number of specific features in each age period. The most pronounced differences are observed in children early age, and after 12 years, the child’s ECG approaches the adult’s cardiogram.
Peculiarities heart rate in children
Typical for childhood high frequency heart rate (HR), newborns have the highest heart rate; as the child grows, it decreases. Children exhibit pronounced lability of heart rate; permissible fluctuations are 15–20% of the average age value. Sinus respiratory arrhythmia is often observed, the degree sinus arrhythmia can be determined using Table 1.
The main pacemaker is the sinus node, however, acceptable variants of the age norm include the mid-atrial rhythm, as well as migration of the pacemaker through the atria.
Duration Features ECG intervals in childhood
Considering that children have a higher heart rate than adults, the duration of ECG intervals, waves and complexes decreases.
Changing the voltage of the teeth QRS complex
Amplitude ECG waves depends on individual characteristics child: electrical conductivity of tissues, thickness of the chest, heart size, etc. In the first 5–10 days of life, a low voltage of the teeth of the QRS complex is noted, which indicates reduced electrical activity of the myocardium. Subsequently, the amplitude of these waves increases. From infancy to 8 years, a higher amplitude of the waves is detected, especially in the chest leads, this is due to the smaller thickness of the chest, large sizes heart relative to the chest and rotations of the heart around its axes, as well as to a greater extent connection of the heart to the chest.
Features of the position electrical axis hearts
In newborns and children in the first months of life, there is a significant deviation of the electrical axis of the heart (EOS) to the right (from 90 to 180°, on average 150°). From the age of 3 months. By the age of 1 year, in most children, EOS turns into vertical position(75–90°), but significant fluctuations in the angle are still allowed (from 30 to 120°). By 2 years, 2/3 of children still maintain the vertical position of the EOS, and 1/3 have a normal position (30–70°). In preschoolers and schoolchildren, as well as in adults, the normal position of the EOS predominates, but variants in the form of a vertical (more often) and horizontal (less often) position may be noted.
Such features of the position of the EOS in children are associated with changes in the ratio of masses and electrical activity of the right and left ventricles of the heart, as well as with changes in the position of the heart in the chest (rotations around its axes). In children in the first months of life, anatomical and electrophysiological predominance of the right ventricle is noted. With age, as the mass of the left ventricle increases rapidly and the heart rotates with a decrease in the degree of adhesion of the right ventricle to the surface of the chest, the position of the EOS moves from the right to the normogram. The changes that are occurring can be judged by the changing ratio of the amplitude of the R and S waves in the standard and chest leads on the ECG, as well as by the displacement of the transition zone. Thus, as children grow in standard leads, the amplitude of the R wave in lead I increases, and in lead III it decreases; the amplitude of the S wave, on the contrary, decreases in lead I and increases in lead III. In the chest leads, with age, the amplitude of the R waves in the left chest leads (V4-V6) increases and decreases in leads V1, V2; the depth of the S waves increases in the right chest leads and decreases in the left ones; The transition zone gradually shifts from V5 in newborns to V3, V2 after the 1st year. All this, plus an increase in interval internal deviation in lead V6 reflects the electrical activity of the left ventricle increasing with age and the rotation of the heart around its axes.
In newborn children, large differences are revealed: the electrical axes of the P and T vectors are located practically in the same sector as in adults, but with a slight shift to the right: the direction of the P vector is on average 55°, the T vector is on average 70°, while the QRS vector is sharply deviated to the right (on average 150°). The value of the adjacent angle between the electrical axes P and QRS, T and QRS reaches a maximum of 80–100°. This partly explains the differences in the size and direction of the P waves, and especially the T waves, as well as the QRS complex in newborns.
With age, the value of the adjacent angle between the electrical axes of the P and QRS, T and QRS vectors decreases significantly: in the first 3 months. life on average up to 40–50°, in young children – up to 30°, and in preschool age reaches figures of 10–30°, as in schoolchildren and adults (Fig. 1).
In adults and children school age the position of the electrical axes of the total vectors of the atria (vector P) and ventricular repolarization (vector T) relative to the ventricular vector (vector QRS) is in the same sector from 0 to 90°, and the direction of the electrical axis of the vectors P (on average 45–50°) and T (on average 30–40°) does not differ sharply from the orientation of the EOS (QRS vector on average 60–70°). Between the electrical axes of the P and QRS, T and QRS vectors, a adjacent angle measuring only 10–30°. This position of the listed vectors explains the same (positive) direction of the P and T waves with the R wave in most leads on the ECG.
Features of teeth intervals and complexes of children's ECG
Atrial complex (P wave). In children, as in adults, the P wave is small (0.5–2.5 mm), with maximum amplitude in standard leads I and II. In most leads it is positive (I, II, aVF, V2-V6), in lead aVR it is always negative, in leads III, aVL, V1 it can be smoothed, biphasic or negative. In children, a slightly negative P wave in lead V2 is also allowed.
Greatest Features P waves are observed in newborns, which is explained by increased electrical activity of the atria due to the conditions of intrauterine circulation and its postnatal restructuring. In newborns, the P wave in standard leads, compared to the size of the R wave, is relatively high (but in amplitude no more than 2.5 mm), pointed, and sometimes may have a small notch at the apex as a result of non-simultaneous coverage of the right and left atria by excitation (but not more than 0 .02–0.03 s). As the child grows, the amplitude of the P wave decreases slightly. With age, the ratio of the size of the P and R waves in standard leads also changes. In newborns it is 1: 3, 1: 4; as the amplitude of the R wave increases and the amplitude of the P wave decreases, this ratio by 1–2 years decreases to 1: 6, and after 2 years it becomes the same as in adults: 1: 8; 1:10. Than smaller child, those shorter duration wave P. It increases on average from 0.05 s in newborns to 0.09 s in older children and adults.
Features of the PQ interval in children. The duration of the PQ interval depends on heart rate and age. As children grow, there is a noticeable increase in the duration of the PQ interval: on average from 0.10 s (no more than 0.13 s) in newborns to 0.14 s (no more than 0.18 s) in adolescents and 0.16 s in adults (no more than 0.20 s).
Features of the QRS complex in children. In children, the time of ventricular excitation coverage (QRS interval) increases with age: on average from 0.045 s in newborns to 0.07–0.08 s in older children and adults.
In children, as in adults, the Q wave is recorded inconsistently, more often in II, III, aVF, left chest leads (V4-V6), less often in I and aVL leads. In lead aVR, a deep and wide Q wave of the Qr type or QS complex is detected. In the right chest leads, Q waves, as a rule, are not recorded. In young children, the Q wave in standard leads I and II is often absent or weakly expressed, and in children of the first 3 months. – also in V5, V6. Thus, the frequency of registration of the Q wave in various leads increases with the age of the child.
In standard lead III in all age groups The Q wave is also small on average (2 mm), but can be deep and reach up to 5 mm in newborns and infants; in early and preschool age - up to 7–9 mm and only in schoolchildren it begins to decrease, reaching a maximum of 5 mm. Sometimes, in healthy adults, a deep Q wave is recorded in standard lead III (up to 4–7 mm). In all age groups of children, the size of the Q wave in this lead can exceed 1/4 of the size of the R wave.
In lead aVR, the Q wave has a maximum depth, which increases with the age of the child: from 1.5–2 mm in newborns to 5 mm on average (with a maximum of 7–8 mm) in infants and at an early age, up to 7 mm on average (with a maximum of 11 mm) in preschool children and up to 8 mm on average (with a maximum of 14 mm) in schoolchildren. The duration of the Q wave should not exceed 0.02–0.03 s.
In children, as well as in adults, R waves are usually recorded in all leads, only in aVR they can be small or absent (sometimes in lead V1). There are significant fluctuations in the amplitude of the R waves in different leads from 1–2 to 15 mm, but the maximum value of the R waves in standard leads is up to 20 mm, and in the chest leads up to 25 mm. The smallest magnitude of R waves is observed in newborns, especially in the strengthened unipolar and chest leads. However, even in newborns, the amplitude of the R wave in standard lead III is quite large, since the electrical axis of the heart is deviated to the right. After 1 month the amplitude of the RIII wave decreases, the size of the R waves in the remaining leads gradually increases, especially noticeably in the II and I standard and in the left (V4-V6) chest leads, reaching a maximum at school age.
In the normal position of the EOS, high R waves with a maximum of RII are recorded in all limb leads (except aVR). In the chest leads, the amplitude of the R waves increases from left to right from V1 (r wave) to V4 with a maximum of RV4, then decreases slightly, but the R waves in the left chest leads are higher than in the right ones. Normally, in lead V1, the R wave may be absent, and then a QS-type complex is recorded. In children, the QS type complex is also rarely allowed in leads V2, V3.
In newborns, electrical alternans is allowed - fluctuations in the height of the R waves in the same lead. Variants of the age norm also include respiratory alternation of ECG waves.
In children, deformation of the QRS complex in the form of the letters “M” or “W” in the III standard and V1 leads is often found in all age groups, starting from the neonatal period. In this case, the duration of the QRS complex does not exceed age norm. Splitting of the QRS complex in healthy children in V1 is referred to as “delayed excitation syndrome of the right supraventricular crest” or “incomplete blockade.” right leg bundle of His." The origin of this phenomenon is associated with the excitation of the hypertrophied right “supraventricular scallop” located in the region of the conus pulmonary of the right ventricle, which is the last to be excited. The position of the heart in the chest and the electrical activity of the right and left ventricles changing with age are also important.
The internal deviation interval (time of activation of the right and left ventricles) in children changes as follows. The activation time of the left ventricle (V6) increases from 0.025 s in newborns to 0.045 s in schoolchildren, reflecting an accelerated increase in the mass of the left ventricle. The activation time of the right ventricle (V1) remains virtually unchanged with the child’s age, amounting to 0.02–0.03 s.
In young children, a change in the localization of the transition zone occurs due to a change in the position of the heart in the chest and a change in the electrical activity of the right and left ventricles. In newborns, the transition zone is located in lead V5, which characterizes the dominance of the electrical activity of the right ventricle. At the age of 1 month. the transition zone shifts to leads V3, V4, and after 1 year it is localized in the same place as in older children and adults - in V3 with fluctuations V2-V4. Together with an increase in the amplitude of the R waves and deepening of the S waves in the corresponding leads and an increase in the activation time of the left ventricle, this reflects an increase in the electrical activity of the left ventricle.
Both in adults and in children, the amplitude of the S waves in different leads varies widely: from absence in a few leads to a maximum of 15–16 mm, depending on the position of the EOS. The amplitude of the S waves changes with the age of the child. Newborn children have the smallest depth of S waves in all leads (from 0 to 3 mm), except standard I, where the S wave is quite deep (on average 7 mm, maximum up to 13 mm).
In children older than 1 month. the depth of the S wave in the first standard lead decreases and subsequently in all leads from the limbs (except aVR) S waves of small amplitude (from 0 to 4 mm) are recorded, just like in adults. In healthy children, in leads I, II, III, aVL and aVF, the R waves are usually larger than the S waves. As the child grows, there is a deepening of the S waves in the chest leads V1-V4 and in lead aVR, reaching a maximum value at high school age. In the left chest leads V5-V6, on the contrary, the amplitude of the S waves decreases, often they are not recorded at all. In the chest leads, the depth of the S waves decreases from left to right from V1 to V4, having the greatest depth in leads V1 and V2.
Sometimes in healthy children with an asthenic physique, with the so-called. “hanging heart”, S-type ECG is recorded. In this case, the S waves in all standard (SI, SII, SIII) and chest leads are equal to or exceed the R waves with reduced amplitude. It is believed that this is due to the rotation of the heart around the transverse axis with the apex posteriorly and around the longitudinal axis with the right ventricle forward. In this case, it is almost impossible to determine the angle α, so it is not determined. If the S waves are shallow and there is no shift of the transition zone to the left, then we can assume that this is a normal variant; more often, the S-type ECG is determined by pathology.
The ST segment in children, as well as in adults, should be on the isoline. The ST segment may shift up and down up to 1 mm in the limb leads and up to 1.5–2 mm in the chest leads, especially in the right ones. These shifts do not mean pathology if there are no other changes on the ECG. In newborns, the ST segment is often not expressed and the S wave, when reaching the isoline, immediately turns into a gently rising T wave.
In older children, as in adults, the T waves are positive in most leads (standard I, II, aVF, V4-V6). In standard III and aVL leads, T waves can be smoothed, biphasic or negative; in the right chest leads (V1-V3) are often negative or smoothed; in lead aVR – always negative.
The greatest differences in T waves are observed in newborns. In their standard leads, the T waves are low-amplitude (from 0.5 to 1.5–2 mm) or smoothed. In a number of leads, where T waves in children of other age groups and adults are normally positive, in newborns they are negative, and vice versa. Thus, in newborns there may be negative T waves in standard I, II, in strengthened unipolar and in the left chest leads; may be positive in standard III and right chest leads. By 2–4 weeks. life, an inversion of T waves occurs, i.e. in the I, II standard, aVF and left chest leads (except V4) they become positive, in the right chest and V4 - negative, in the III standard and aVL they can be smoothed, biphasic or negative.
In subsequent years, negative T waves persist in lead V4 until 5–11 years, in lead V3 – up to 10–15 years, in lead V2 – up to 12–16 years, although in leads V1 and V2 negative T waves are allowed in some cases and in healthy adults.
After 1 month During life, the amplitude of T waves gradually increases, amounting in young children from 1 to 5 mm in standard leads and from 1 to 8 mm in chest leads. In schoolchildren, the size of T waves reaches the level of adults and ranges from 1 to 7 mm in standard leads and from 1 to 12–15 mm in chest leads. The T wave is largest in lead V4, sometimes in V3, and in leads V5, V6 its amplitude decreases.
The QT interval (ventricular electrical systole) makes it possible to assess the functional state of the myocardium. The following features of electrical systole in children can be identified, reflecting the electrophysiological properties of the myocardium changing with age.
The duration of the QT interval increases as the child grows from 0.24–0.27 s in newborns to 0.33–0.4 s in older children and adults. With age, the relationship between the duration of electrical systole and the duration of the cardiac cycle changes, which is reflected by the systolic index (SP). In newborn children, the duration of electrical systole occupies more than half (SP = 55–60%) of the duration of the cardiac cycle, and in older children and adults – 1/3 or slightly more (37–44%), i.e., with age, SP decreases.
With age, the ratio of the duration of the electrical systole phases changes: the excitation phase (from the beginning of the Q wave to the beginning of the T wave) and the recovery phase, i.e., rapid repolarization (duration of the T wave). In newborns recovery processes in the myocardium, more time is spent than on the excitation phase. In young children, these phases take approximately same time. In 2/3 of preschoolers and most schoolchildren, as well as in adults, more time is spent on the arousal phase.
Features of ECG in various age periods childhood
Newborn period (Fig. 2).
1. In the first 7–10 days of life, there is a tendency towards tachycardia (heart rate 100–120 beats/min), followed by an increase in heart rate to 120–160 beats/min. Pronounced heart rate lability with large individual fluctuations.
2. A decrease in the voltage of the QRS complex waves in the first 5–10 days of life with a subsequent increase in their amplitude.
3. Deviation of the electrical axis of the heart to the right (angle α 90–170°).
4. The P wave is relatively larger (2.5–3 mm) in comparison with the teeth of the QRS complex (P/R ratio 1: 3, 1: 4), often pointed.
5. PQ interval does not exceed 0.13 s.
6. The Q wave is unstable, as a rule, absent in standard I and in the right chest leads (V1-V3), it can be deep up to 5 mm in standard III and aVF leads.
7. The R wave in standard lead I is low, and in standard lead III it is high, with RIII > RII > RI, high R waves in aVF and right precordial leads. The S wave is deep in standard I, II, aVL and in the left precordial leads. The above reflects the deviation of the EOS to the right.
8. Low amplitude or smoothness of T waves in the limb leads is noted. In the first 7–14 days, the T waves are positive in the right chest leads, and in the I and left chest leads they are negative. By 2–4 weeks. life, an inversion of the T waves occurs, i.e. in the I standard and left pectorals they become positive, and in the right pectorals and V4 they become negative, remaining so in the future until school age.
Infancy: 1 month – 1 year (Fig. 3).
1. Heart rate decreases slightly (on average 120–130 beats/min) while maintaining rhythm lability.
2. The voltage of the QRS complex teeth increases, often higher than in older children and adults, due to the smaller thickness of the chest.
3. In most infants, the EOS goes into a vertical position, some children have a normogram, but significant fluctuations in the α angle are still allowed (from 30 to 120°).
4. The P wave is clearly expressed in standard leads I and II, and the ratio of the amplitude of the P and R waves decreases to 1: 6 due to an increase in the height of the R wave.
5. The duration of the PQ interval does not exceed 0.13 s.
6. The Q wave is recorded inconsistently and is often absent in the right precordial leads. Its depth increases in standard III and aVF leads (up to 7 mm).
7. The amplitude of the R waves in standard I, II and in the left thoracic (V4-V6) leads increases, and in standard III it decreases. The depth of the S waves decreases in standard I and in the left chest leads and increases in the right chest leads (V1-V3). However, in VI, the amplitude of the R wave, as a rule, still prevails over the magnitude of the S wave. The listed changes reflect the shift of the EOS from the correct position to the vertical position.
8. The amplitude of the T waves increases, and by the end of the 1st year the ratio of the T and R waves is 1: 3, 1: 4.
ECG in young children: 1–3 years (Fig. 4).
1. Heart rate decreases to an average of 110–120 beats/min, and in some children sinus arrhythmia appears.
3. EOS position: 2/3 of children maintain a vertical position, and 1/3 have a normogram.
4. The ratio of the amplitude of the P and R waves in standard leads I, II decreases to 1: 6, 1: 8 due to the increase in the R wave, and after 2 years it becomes the same as in adults (1: 8, 1: 10) .
5. The duration of the PQ interval does not exceed 0.14 s.
6. Q waves are often shallow, but in some leads, especially in standard III, their depth becomes even greater (up to 9 mm) than in children of the 1st year of life.
7. The same changes in the amplitude and ratio of the R and S waves that were noted in infants continue, but they are more pronounced.
8. There is a further increase in the amplitude of the T waves, and their ratio with the R wave in leads I and II reaches 1: 3 or 1: 4, as in older children and adults.
9. Negative T waves remain (options: biphasic, smooth) in standard III and right chest leads up to V4, which is often accompanied by a downward shift of the ST segment (up to 2 mm).
ECG in preschool children: 3–6 years (Fig. 5).
1. Heart rate decreases to an average of 100 beats/min, and moderate or severe sinus arrhythmia is often recorded.
2. Saved high voltage teeth of the QRS complex.
3. EOS is normal or vertical, and very rarely there is a deviation to the right and a horizontal position.
4. PQ duration does not exceed 0.15 s.
5. Q waves in various leads are recorded more often than in previous age groups. The depth of the Q waves in standard III and aVF leads remains relatively large (up to 7–9 mm) compared to that in older children and adults.
6. The ratio of the size of the R and S waves in standard leads changes towards an even greater increase in the R wave in standard leads I and II and a decrease in the depth of the S wave.
7. The height of the R waves in the right chest leads decreases, and in the left chest leads it increases. The depth of the S waves decreases from left to right from V1 to V5 (V6).
ECG in schoolchildren: 7–15 years (Fig. 6).
The ECG of schoolchildren is close to the ECG of adults, but there are still some differences:
1. Heart rate decreases on average junior schoolchildren up to 85–90 beats/min, in older schoolchildren – up to 70–80 beats/min, but there are wide fluctuations in heart rate. Moderate and severe sinus arrhythmia is often recorded.
2. The voltage of the QRS complex teeth decreases somewhat, approaching that of adults.
3. Position of the EOS: more often (50%) – normal, less often (30%) – vertical, rarely (10%) – horizontal.
4. The duration of ECG intervals approaches that of adults. The PQ duration does not exceed 0.17–0.18 s.
5. The characteristics of the P and T waves are the same as in adults. Negative T waves persist in lead V4 up to 5–11 years, in V3 – up to 10–15 years, in V2 – up to 12–16 years, although negative T waves in leads V1 and V2 are also allowed in healthy adults.
6. The Q wave is recorded inconsistently, but more often than in young children. Its value becomes smaller than in preschool children, but in lead III it can be deep (up to 5–7 mm).
7. The amplitude and ratio of the R and S waves in various leads approach those in adults.
Conclusion
To summarize, we can highlight the following features of the pediatric electrocardiogram:
1. Sinus tachycardia, from 120–160 beats/min during the newborn period to 70–90 beats/min by high school age.
2. Greater variability of heart rate, often sinus (respiratory) arrhythmia, respiratory electrical alteration of QRS complexes.
3. The norm is considered to be average, inferior atrial rhythm and migration of the pacemaker through the atria.
4. Low QRS voltage in the first 5–10 days of life (low electrical activity of the myocardium), then an increase in the amplitude of the waves, especially in the chest leads (due to thin chest wall and the large volume occupied by the heart in the chest).
5. Deviation of the EOS to the right up to 90–170º during the newborn period, by the age of 1–3 years – transition of the EOS to a vertical position, by adolescence in about 50% of cases – normal EOS.
6. Short duration of intervals and waves of the PQRST complex with a gradual increase with age to normal limits.
7. “Syndrome of delayed excitation of the right supraventricular crest” – splitting and deformation of the ventricular complex in the form of the letter “M” without increasing its duration in leads III, V1.
8. Pointed high (up to 3 mm) P wave in children in the first months of life (due to the high functional activity of the right side of the heart in the prenatal period).
9. Often – deep (amplitude up to 7–9 mm, more than 1/4 of the R wave) Q wave in leads III, aVF in children up to adolescence.
10. Low amplitude of T waves in newborns, increasing by the 2nd–3rd year of life.
11. Negative, biphasic or smoothed T waves in leads V1-V4, persisting until the age of 10–15 years.
12. Shift of the transition zone of the chest leads to the right (in newborns - in V5, in children after the 1st year of life - in V3-V4) (Fig. 2–6).
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3. Isakov I.I., Kushakovsky M.S., Zhuravleva N.B. Clinical electrocardiography. L.: Medicine, 1984.
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The heart muscle is the main mechanism human body. Horizontal position- What is this? To confirm heart disease, various indicators of heart function are considered. Horizontal position and other axis displacements indicate heart disease and vascular problems.
Incorrect position of the electrical axis of the heart may indicate the development of cardiac pathology
Electrical axis of the heart - numbers characterizing the condition electrical processes in heart. The concept is used by cardiologists when diagnostic study condition and functioning of the heart muscle. The axis reflects the electrodynamic capabilities of the heart.
The conduction system of the heart vessels consists of atypical fibers and determines the functioning of the EOS. The system is a source that supplies electrical discharges. Electrical changes occur in it, causing the heart to contract. If the conductive system operates incorrectly, the electrical axis changes direction.
Considered sinus. An impulse is generated at the location of the sinus node, and the myocardium contracts. The impulse then moves along the precardioventricular canal and enters the mass of muscle fibers - the bundle of His. Consists of several directions and branches. When the heart contracts, they receive a nerve impulse.
In people with good health The left heart ventricle weighs slightly more than the right. They explain that it does a lot of work to release plasma and blood into the arteries. Therefore, the muscles and blood vessels of the left ventricle are stronger and more powerful. Hence the impulses in it are stronger, which explains the location of the heart on the left.
EOS is described using a vector line formed from the sum of two vectors. The axis angle ranges from 0 to 90 degrees, sometimes it varies slightly. The numbers show normal work cardiac and vascular systems.
To correctly diagnose the direction of the axis, doctors take into account the patient’s body composition, which affects its correct placement. From the normal position it changes to horizontal and vertical.
Vertical is inherent in thin people with an asthenic physique. In thin patients, the correct direction of the electrical axis is vertical. If it is displaced and horizontal, or deviated to the side, this means a complex pathology.
There are four axis positions:
In children, the position of the EOS changes as they grow and develop
In infants under 12 months of age, the direction of the b axis is noted on the electrocardiogram. right side. During the course of a year, children's EOS changes and becomes vertically positioned. This is explained by growth processes: the right parts of the heart exceed the left ones in strength, activity and mass. Changes in the location of the heart muscle are noticeable.
By the age of 2-3 years, the axis in 60% of children is vertical, in the rest it changes to normal. This occurs due to growth, enlargement of the left ventricle and reversal of the heart. In preschoolers and older children, the normal position of the EOS dominates.
The correct location of the axis in children is considered:
The position of the EOS can be changed during heart block
In the absence of signs of disease, deviations of the axis in different directions are not considered pathology. If they appear cardiovascular problems, then incorrect placement of the EOS indicates disorders and diseases:
In addition to the reasons listed, changes in the direction of the EES indicate diseases of the heart muscle and. Axis deviations are often noted in athletes and people performing heavy physical work.
A shift of the EOS to the left may indicate the development of left-sided myocardial infarction
The deviation of the axis to the left is considered to be in the range from 0 to -90 degrees. Diseases accompanied by an axis tilt to the left have been identified:
These diseases increase the weight and size of the left ventricle. The vector impulse travels longer on the left side, the axis moves to the left.
The axis is directed to the right and is located in the range +90 - +180 degrees for diseases:
To determine the causes of axis displacement, diagnostics are prescribed and concomitant inflammatory processes are studied.
The resulting vector of all bioelectrical oscillations of the heart muscle is called electric axle. Most often it coincides with the anatomical one. This indicator is used when analyzing ECG data to assess the dominance of one part of the heart, which may be indirect sign myocardial hypertrophy.
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The direction of the heart axis is calculated in degrees. To do this, they use such a concept as the alpha angle. It is formed by a horizontal line that is drawn through the electrical center of the heart. To determine it, the axis of the first ECG leads moves towards the center of Einthoven. This is a triangle, its vertices are the hands spread out to the side and the left foot.
In a healthy person, the electrical axis fluctuates between 30 and 70 degrees. This is due to the fact that the left ventricle is more developed than the right, therefore, more impulses come from it. This position of the heart occurs with a normosthenic physique, and the ECG is called a normogram.
A change in the direction of the heart axis on an electrocardiogram is not always a sign of pathology. Therefore, for making a diagnosis, its deviations are of auxiliary importance and are used for the preliminary formulation of the conclusion.
Pravogramma (alpha 90 - 180) on the ECG occurs with an increase in the mass of the myocardium of the right ventricle. The following diseases lead to this condition:
Cardiomyopathy is one of the causes of deviation of the heart axis to the right A left-side shift of the electrical axis (alpha from 0 to minus 90) occurs quite often. Leads to him. This may be due to the following conditions:
In order to identify the position of the axis, it is necessary to examine two leads aVL and aVF. You need to measure the tooth in them R. Normally, its amplitude is equal. If it is high in aVL and absent in aVF, then the position is horizontal; in vertical it will be the other way around.
There will be an axis deviation to the left if R in the first standard lead is greater than S in the third. Pravogram - S1 exceeds R3, and if R2, R1, R3 are arranged in descending order, then this is a sign of a normogram. For a more detailed study, special tables are used.
If the ECG reveals an axis shift to the right or left, then the following are used to clarify the diagnosis: additional methods examinations:
If there is only a pathological alpha angle, and no other manifestations are detected on the ECG, the patient does not experience difficulty breathing, pulse and blood pressure are normal, then no further actions such a condition does not require. This may be due to an anatomical feature.
A more unfavorable sign is pravogramma with lung diseases, as well as levogramma combined with hypertension. In these cases, the displacement of the heart axis can be used to judge the degree of progression of the underlying pathology. If the diagnosis is unknown, and there is a significant axis deviation with cardiac symptoms, then the patient should be fully examined to identify the cause of this phenomenon.
The displacement of the electrical axis can be to the left or to the right, depending on which of the heart ventricles the activity predominates. Such changes in the ECG are an indirect sign of myocardial hypertrophy and are considered in conjunction with other indicators. If there are complaints about heart function, it is required additional examination. In children younger age pravogramma is a physiological condition that does not require intervention.
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During a routine examination, a person over 40 years of age should have a cardiogram done to identify heart pathologies. The location of the teeth allows us to determine the state of the organ during excitation.
Deviation of the electrical axis of the heart to the left indicates certain diseases and requires clarification of the diagnosis.
The electrical activity of the body’s “motor” is recorded using an ECG. To imagine what the heart axis is, it is necessary to construct a coordinate scale and mark the directions in increments of 300. The semi-vertical position of the organ in the chest when superimposed on the coordinate system sets the electrical axis.
Vectors make an angle, so the direction of the EOS is measured in degrees from -180 to +1800. In a normal location, it should be in the range +30 - +69.
If, under the influence of any factors, a change in the position of the organ and the vector of signal transmission occurs, then they speak of its change in the coordinate system.
Normally the heart has sinus rhythm, the electrical impulse begins from the atrium and then moves to the ventricles. On an electrocardiogram, the normal position of the organ can be determined if the P wave is detected, indicating atrial contraction, the QRS complex, contraction of the ventricles and T, their repolarization.
The location of the terminals when taking an ECG is the direction of the electrical impulse of the heart. When removing the leads, 3 main and 3 auxiliary lines are determined, as well as chest indicators.
Talk about normal value axis is possible if the R tooth has highest value in the 2nd main lead, and the value is R1>R3.
If there is a shift in the electrical axis to the left, what does this mean? There are factors that cause the organ to preponderate to the left. A leftogram is observed if the axis position is from 0 to -900.
The EOS is deviated to the left not only in cardiac pathologies. The reasons for the deviation are left ventricular hypertrophy, provoked by the following disorders:
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During the cardiac cycle, during the first contraction, blood is pushed into the atrium, the valve closes, then it is transferred to the ventricle, and with the next contraction all the blood must go into the vessels.
If the pumping function is impaired, when the organ is not able to contract with such force to push out all the fluid, part of it constantly remains inside the cavity. It gradually stretches.
This phenomenon is provoked by cardiomyopathy due to ischemic heart disease due to heart attack, myocarditis.
The second reason for residual fluid accumulation: the valve does not close completely, or there is stenosis, a narrowing of the lumen of the vessel. Then some of the blood returns back or cannot exit into the aorta in one cycle.
Heart disease can be congenital or acquired. In the first case, it is detected during examination of a newborn child, in the second, in an adult.
If the conduction of the left bundle branch is disrupted, the functioning of the left ventricle is disrupted, which is why it does not contract as it should. In this case, sinus rhythm is maintained, but the axis deviates.
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At arterial hypertension Blood pressure on the vessels increases, which affects their condition. The more often blood pressure rises, the more likely decreased elasticity of blood vessels and expansion of the ventricle, which bears a large load.
At atrial fibrillation, in addition to changes in the electrical axis of the heart, there is a lack of atrial contraction, and ventricular complexes are formed at different intervals.
The deviation itself does not manifest symptoms, but since the disorder is caused by certain reasons, signs appear when the process spreads significantly.
Hemodynamic disturbances occur, and there are accompanying symptoms.
If the patient has heart failure or a heart defect, this is manifested by the appearance of shortness of breath when walking or climbing stairs, blueness of the limbs and nasolabial triangle, shortness of breath and dizziness.
Atrial fibrillation is manifested by attacks during which there is not enough breathing, a feeling of palpitations, pain in the chest, and irregular pulses.
Arterial hypertension is manifested by headache, mainly in the back of the head, heaviness in the chest, with high values- flashing of flies before the eyes.
Bringing together the symptoms of the disorder helps to identify the disorder. functional diagnostics, other methods:
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Thanks to these studies, it is possible to visually assess the organ and its parts, determine the size of the enlarged cavity, and establish the cause of the insufficiency.
Using electrocardiography with a load in the form of a bicycle track or an exercise bike, it is possible to determine at what point myocardial ischemia appears.
The doctor prescribes a daily test if he suspects that the patient has a rhythm disorder. To “catch” periods of arrhythmia, a person is fitted with a device for a day that records the contraction of the heart.
Angiocoronary angiography is a study of blood vessels that allows you to see their condition and circulatory disorders. The image allows you to determine the expansion of the shadow of the organ, which indicates hypertrophy.
Standard EOS indicators are approximately the same for everyone, but in a tall person the size of the heart and its position may be slightly different, although he will not be sick. Therefore, when initial examination If a violation is established, additional research methods are required.
A change in the parameter normally also occurs in athletes.
Because they endure significant stress during constant training, their heart pumps large volumes of fluid, causing the cavities to stretch. They may exhibit a horizontal type of deviation, when the organ occupies a position from -15 to +30.
If during the study a person did deep breath or changed the position of the body, then even if normal, a deviation will be detected healthy heart to the left.
During the examination, an electrocardiogram can be used to determine the presence of a deviation to the left side. In the diagram, the R wave is largest in lead 1.
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An additional sign is the location of the QRS complex below the isoline in column 3, that is, S predominates. If you pay attention to the leads from the arms and legs, then in AVF the ventricular complex will be the same as III.
Since the angle of deviation from the norm can be different, the degrees of the process also differ. Changing degrees is a gradual process. The larger the cavity size grows, the more the indicator deviates from the norm. If the deviation is from -450 to -900 degrees relative to the norm, then they say that the organ is sharply shifted to the left.
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A displacement of the axis of the heart in the chest may indicate a violation conducting an ECG, if the person is in good health and no other health problems have been identified.
Normally, it is observed in people who regularly engage in physical activity and in athletes.
The pronounced deviation is not accidental; it is a sign of pathology in adults. Stagnation may occur and accumulate over several years.
During the neonatal period, a child experiences a sharp deviation of the axis to the right; this is the norm. If an adult has such a disorder, then he has signs of right ventricular hypertrophy.
In a child, this is due to the fact that the right parts of the heart have a large mass, predominant over the left. By the age of one year, the condition is normalized, and the organ should assume a vertical position in the chest. During this period, it can rotate around its axis in different directions.
Then the left ventricle gains mass and ceases to adhere to the chest. By the age of 6-7 years, the organ acquires a correct, semi-vertical position.
The heart axis is a criterion by which a health disorder can be determined, therefore, in case of deviation, therapy is aimed at combating the cause identified during diagnosis. If you eliminate it, you will be able to restore normal functioning hearts.
These may be the following procedures:
The set of measures depends on the degree of health impairment present.
If the arrhythmia is periodic and can be eliminated with the help of drugs, then suitable remedy. If a threat to life appears, the issue of installing a pacemaker is decided.
Coronary bypass surgery is the cleaning of blood vessels from plaques and lipid plaque, which expands their lumen and eliminates ischemia.
In the case of congenital and acquired heart disease or CHF, it helps to establish normal cardiac cycle. If the pumping function of the heart is affected, then weak contractility myocardium.
It is not the deviation of the heart position that is dangerous, but the reasons why it occurs. Complications of left ventricular hypertrophy:
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All causes of organ dysfunction are interconnected. If a heart defect leads to dilatation of the left ventricle, then with the development pathological process Rhythm disturbances are to be expected. If the myocardium becomes so weak that contraction of the fibers does not lead to the release of blood further, then circulatory failure and cardiac arrest occur.
If the electrical axis of the heart (EOS) is deviated to the left or right, this may indicate problems with the functioning of this organ. Let's look at why this can happen, when it is dangerous and when it is not, and how this condition is treated.
The position of this axis is determined by electrocardiography, after analyzing an electrocardiogram from several leads.
To detect change normal location axes 2 methods can be used.
This technique is most often used by diagnosticians. Normally, the EOS completely coincides with the anatomical axis (the heart is located semi-vertically, and the lower end deviates down and slightly to the left). Its location is determined by the alpha angle formed from 2 straight lines (1 abduction axis and the EOS vector line).
To identify the angle, the sum of the S, R and Q waves in 3 and 1 standard leads is calculated. The positive and negative value of each tooth must be taken into account.
Diede's table is then used. Having entered the result, the doctor determines the criteria for the alpha angle.
Here's what it looks like:
Click on the picture to enlarge
Normally, this angle should be from – 29° to +89°. Significant left-sided displacement of the axis is a sign pathological disorders. When it changes to -30°, we are talking about a left-sided deviation, and with values from +90° to +180° - a right-sided deviation.
Left-sided deviation of the angle from – 30° to – 44° is insignificant, at – 45° to – 90° it is considered significant and in most cases accompanies cardiac pathologies.
This technique for determining the displacement of the heart axis is most often used by therapists and cardiologists. After an ECG, the doctor compares the magnitude of the S and R waves in leads 1 and 3. If within one of them the value of R is greater than S, we are talking about a ventricular complex (R-type). Otherwise, the complex belongs to the S-type.
When the axis deviates to the left, tooth RI - SIII. This means that the ventricular complex is R-type in lead 1, and S-type in lead 3.
Standard lead of QRS waves in different positions of the EOS (a, b – right-sided displacement; c – normal position of the axis; d, e – left-sided displacement) The main tool for determining deviations of the EOS to the left is electrocardiography, however, a number of auxiliary studies are necessary to confirm the result.
After an ECG is performed, its results are carefully studied to identify the cause. pathological condition. In most cases, a repeat cardiogram is prescribed, which is necessary to eliminate technical errors (incorrect application of electrodes, device malfunction, etc.).
It must be taken into account that deviation of the EOS to the left is just an ECG sign indicating diffuse changes at various pathologies Therefore, a comprehensive diagnosis must be prescribed.
Changes in heart activity on the electrocardiogram are provoked by many factors.
Let's consider each case in more detail.
The main reason for the shift to the left of the heart axis is left ventricular hypertrophy. Changes can be provoked by: ischemia (including heart attacks and), aortic and mitral valve, cardiomyopathy, myocardial dystrophy and other diseases.
Changes in the cardiogram are possible with atrial fibrillation, heart defects (acquired and congenital), .
A slight deviation of the EOS on electrocardiography is often found in quite healthy people, for example, athletes, thin and tall patients.
The electrical axis can shift to the left during deep exhalation, a high-standing diaphragm, and when the body position changes (from vertical to horizontal), which is caused by compression of the diaphragm internal organs. Such shifts are considered quite normal.
In children, EOS can change according to age. For example, newborns are characterized by a right-sided deviation and this is not a pathology. IN adolescence the EOS angle has stable indicators.
Most often in children, left-sided axis deviation (up to –90°) is caused by birth defects, which can be complicated by concomitant cardiovascular anomalies. This is possible with an open ductus arteriosus, in case high loads on the left ventricle, which happens with mitral heart defects or coarctation of the aorta. Such a picture in a child is possible with a defect interventricular septa or when the diaphragmatic dome is high.
A shift of the axis to the left (from 0 to –20°) is also possible due to a change in the position of the ventricles. Congenital heart disease with incomplete atrioventricular communication, as well as defects interatrial septum, are also accompanied by a change in the axis from –20° to –60°.
EOS displacement is not a disease, therefore it is not characterized by certain Clinical signs. In addition, the pathologies that cause it can also occur with mild symptoms. In this case, deviations of the electrical axis of the heart to the left are often detected only when deciphering the electrocardiogram.
There are certain symptoms associated with individual diseases. For example, with hypoxia of the left ventricle, they are expressed by paroxysmal pain in the chest and surges in blood pressure. Tachycardia and severe headache. With left bundle branch block, fainting and bradycardia are possible.
Deviation of the heart axis to the left does not require the use of specific therapy. All measures are aimed at neutralizing the underlying disease, accompanied by displacement of the EOS and disruption. For arterial hypertension, prescribed antihypertensive drugs, ischemia requires the use of ACE inhibitors, statins, and beta-blockers.
Deviation of the EOS does not pose a threat to the patient’s life, but if the position of the axis changes very sharply, there is a possibility of blockade of the legs of His. If such changes are detected, a mandatory consultation with a cardiologist is required to clarify the diagnosis. This approach makes it possible to timely identify a borderline state in the heart.
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