Teeth and ECG intervals decryption. What ECG indicators are considered normal: decoding survey results

31.10.2020

Electrocardiography or ECG Hearts is a survey, during which the device perceives electrical cardiac activity. The ECG results are a graph, as a rule, recorded on millimeter paper in the form of a curve showing changes in voltage between two points over time.

Electrocardiography is a quick, cheap and easy-to-person survey reporting important information about the heart function. Therefore, it refers to major medical examinations.

Many know what a doctor does the ECG. The electrocardiogram makes a cardiologist, he also conducts decipher. Today, cardiologist services are available online, where it is also possible to estimate the results of the examination - that is, you can easily go to the page - and decipher your heart activities!

Operating principle

The stimulus to reduce any muscle cells is the change in the voltage between the inner and outer medium of the cell. The same applies to the heart muscle, the cells of which should work very stable.

The initial electrical impulse is produced in specialized cells in the atrium cluster (sinus node), from where the quick paths are distributed throughout the heart so that the heart muscle is coordinated to complicate and effectively pushed blood from the heart cavities.

When weakening the cardiac muscle, the voltage returns to its original state. These electrical changes during cardiac work apply to the body surface (we are talking about malelvolts), where they are scanned through the electrodes - this is a brief ECG description.

When and why is it held?

ECG is the necessary examination with suspected heart disease. Electrocardiography is used in the diagnosis of ischemic changes of the heart muscle, i.e., changes from the lack of oxygen, the most serious manifestation of which is the death of cardiac cells due to lack of oxygen - myocardial infarction.

In addition, an ECG analysis can show arrhythmia - a violation of heart rhythm.

ECG conclusion reveals and expanding the heart in its insufficiency or pulmonary artery embolism. The cardiogram is usually carried out within the framework of a preoperative survey before the planned procedure under general anesthesia, or during a general survey.

Before expertise, there is no need to comply with any special regime. It is only calm.

Examination

In adults and children, the ecg is the same. The examination patient must undress to the belt, if necessary, remove socks or stockings - the pectoral, ankle and wrist should be available.

The survey is carried out in the lying position. A nurse or a doctor who performs an examination makes a patient, an adult or a child, a slightly conductive gel that improves the transmission of electrical signals to the electrodes. Then the electrodes themselves are attached using rubber suckers. There are electrodes in the form of stickers (disposable), already impregnated with gel.

In total, there are 10 electrodes: 6 - on the chest and 1 on each limb. When all electrodes are placed, an electrocardiograph is turned on, and within a few seconds, paper from an electrocardiographic curve is derived from the device - electrocardiography is completed.

Modification ECG

There are several ways to measure the main performance of the heart:

daily monitoring of the ECG on the holder;
intermittent daily monitoring;
load monitoring;
esophageal monitoring.

Daily monitoring of ECG on Holter

This survey is carried out mainly in adults; The surveyed person is attached to the device within 24-48 hours. Electrodes are located on the chest, and the device is fastened around the waist, the patient can work normally with it and perform any other ordinary activities.

This study is very important in the diagnosis of heart rhythm disorders that occur periodically to confirm or eliminate certain problems related to heart disease. The patient during the survey leads a diary, and in case of manifestation of symptoms of the disease, independently writes time. The doctor subsequently can decipher ECG in this time period.

This study is also practiced, mainly in an adult in case of symptoms that arise less often. Man wears a device longer than a day or two, activating it when difficulties occur.

Load monitoring

Usually called bicycle ergometry; Explore the work of the heart at an increased load. The survey can be carried out in both adults and children. The patient gets a load on the treadmill, at this time the device reflects its cardiac activity.

Esophageal monitoring

This is a less common examination conducted by an empty stomach. The patient is introduced the electrode in the esophagus through the mouth or nose. The electrode is thus located very close to the left atrium, which provides a better curve than a regular entry, read ECG easier. Used in cases where, with classical ECG, the decryption was undefined, or as a therapeutic method, when electrical stimulation provides physiological healthy rhythm.

Decoding curve

Cardiogram decoding consists of 10 points:

heartbeat;
sinus rhythm;
heart rate;
prong p;
pQ interval;
QRS complex;
sT segment;
teeth T;
qt interval;
heart axis.

Normal performance provides the following table:

The norm in the table is specified for adults. In children, the ECG is another, varies depending on age-related changes.

The most important parameter in the question how to decipher the cardiogram is QRS complex, its shape and ECG teeth. The basis of vibrations and deviations are changes in the electric field of the heart. Sine arrhythmia on ECG is characteristic of irregular intervals R-R, i.e., repetition of QRS.

The duration of the QRS complex is measured from the beginning of the wave q to the end of the wave S, and indicates the duration of the reduction in the cardiac chamber. Normal ECG in this plan is 0.08-0.12 seconds. The form of QRS in a healthy patient should be regular and constant.

In principle, the perfect cardiogram is constantly repeating QRS complexes at regular intervals, and QRS has the same form.

To decipher the cardiogram of the heart, in addition to manual reading, specialized software is used today. It not only decrypts the data, but also analyzes the signal. Modern methods are capable of much more accurate to detect even the smallest pathological changes in cardiac rhythm.

Teeth R.

The physiological teeth of P precedes each QRS complex, from which the PQ interval is separated. The frequency of occurrence is thus coincided with the frequency of systole.

The positiveness and negativity, amplitude and duration of the teeth p are estimated.

Positacity and negativity. Physiologically, the teeth P in I and II taps are positive, in the III of the tap - positive or negative. Negative P in I or II tap - pathological.
Amplitude. In normal mode, the amplitude of the teeth P does not exceed 0.25 mV. Higher values \u200b\u200bindicate hypertrophy.
The duration of the teeth P does not exceed 0.11 seconds. The elongation indicates the dilatation of the atrium, the prong is called P Mitrale, and is typical for the mitral stenosis of the valve.

Interval PQ.

The PQ interval corresponds to an atrium systole and air delay in AV node. It is measured from the beginning of the priest R before the beginning of the ventricular complex. Normal values \u200b\u200b- from 0.12 to 0.20 seconds.

Pathology:

the prolonged PQ interval occurs in the AV unit blocks;
the abbreviated PQ interval indicates the pre-excitation syndrome (air bypasses AV node via parallel connections).

If the PI does not contain a heart cardiogram, the decryption of the PQ interval is not conducted (the same applies to the case if the PC is not dependent on the QRS complex).

QRS complex

QRS complex represents a reduction in the ventricular heart muscle:

Q - the first negative oscillation may be absent;
R - Each positive oscillation. Usually only one is present. If there are more than 1 oscillations in the complex, it is indicated by an asterisk (for example, R *);
S - Each negative oscillation after at least one R. More oscillations is similar to R.

3 factors are estimated at QRS complex:

duration;
the presence and duration q;
sokolov indexes.

If, after a general estimate of the ECG, BLNPG is detected, Sokolov indexes are not measured.

QRS indicators:

QRS duration. The physiological duration of the QRS complex is up to 0.11 s. Pathological extension to 0.12 p. It may indicate an incomplete blockade, myocardial infarction and ventricular hypertrophy. Extension over 0.13 s. Specifies to BLNPG.
Q oscillations. In all conclusions q oscillations are determined. They are usually present. However, their duration does not exceed 0.03 p. The only exception is the oscillation of AVR, in which q is not pathological.

Q longer than 0.04 p. Clearly shows the scar after myocardial infarction. According to their individual oscillations, you can determine the location of the heart attack (front wall, septal, diaphragmal).

Sokolov indexes (Criteria Sokolov-Lyon Golders Hypertrophy)

From the size of the amplitude of oscillations of QRS, you can approximately determine the thickness of the chamber wall. This uses Sokolov indices, 1 - for right and 2 for left ventricle.

Right ventricular indicators:

the sum of the amplitude of the teeth P in the taps V1, S and in the V6 is usually no exceeds 1.05 mV;
normal indicators: R (v1) s + (v6)<1,05 мВ;
hypertrophy of the right ventricle to ECG: ≥ 1.05 mV.

To determine the left ventricle hypertrophy there are 2 Sokolov index (LK1, LK2). In this case, amplitudes are also summed up, but in oscillations s in the V1 rally and in the oscillation R in the discharges V5 or V6.

LK1: S (V1) + R (V5)<3,5 мВ (норма);
LK2: S (V1) + R (V6)<4 мВ (норма).

If the measured values \u200b\u200bexceed the norm, they are noted as pathological. The following indicators indicate on the left ventricular hypertrophy:

LK1: S (V1) + R (V5)\u003e 3.5 mV;
LK2: S (V1) + R (V6)\u003e 4 mV.

Teeth T.

Tusk T per ECG represents the repolarization of the myocardium of ventricles and is physiologically concordable. Otherwise, it is described as discponder, which is pathological. Teeth of T is described in I, II and IIIans, in AVR and in breast taps V3-V6.

I and II - positive concordant;
III - concordant (polarity does not matter);
aVR - negative Tusk T per ECG;
V3-V6 is positive.

Any deviation from the norm is pathological. Sometimes the Tuscom T is bipolar, in which case it is described as preterminally negative (- / +) or terminally negative (+/-).

Deviations of the Tusque tons occur during myocardial hypoxia.

High Teeth T (i.e. Gothic) is typical for an acute heart attack.

Qt interval

The distance from the beginning of the ventricular QRS complex is measured to the end of the teeth of T. normal values \u200b\u200bare 0.25-0.50 s. Other values \u200b\u200bindicate an error in the conduct of the examination or in the ECG estimate.

Results of research

The result of the study is available immediately, then its estimate (decoding ECG) depends on the doctor. It can determine the fact that the heart does not suffer from the lack of oxygen, does it work in the right rhythm, whether the number of shots per minute and so on.

Some heart diseases, however, an ECG may not determine. These include, for example, arrhythmia, which manifests periodically, or violation of cardiac activity in any physical activity. If such a cardiology disorder is suspected, the doctor must perform some additional tests.

Currently in clinical practice is widely used electrocardiography method (ECG). ECG reflects the excitation processes in the heart muscle - the occurrence and distribution of excitation.

There are various ways to disrupt the electrical activity of the heart, which differ from each other by the location of the electrodes on the surface of the body.

Heart cells, coming to the excitation state, become the source of the current and cause the field occurrence in the environment.

In veterinary practice, the electrocardiography use different systems of alliances: the imposition of metal electrodes on the skin in the chest, heart, limbs and tail.

Electrocardiogram (ECG) - a periodically repeated curve of heart biopotentials, reflecting the flow of the process of excitation of the heart, which arose in a sine (sine-atrial) node and spreading throughout the heart, recorded with an electrocardiograph (Fig. 1).

Fig. 1. Electrocardiogram

Separate elements - Teeth and intervals - Received special names: Teeth R,Q., R., S., T.intervals R,PQ., QRS., Qt, RR; Segments PQ., ST, TP., Characterizing the occurrence and distribution of excitation by atria (P), interventricular partition (Q), gradual excitation of ventricles (R), maximum excitation of ventricles (S), ventilation repolarization (S) of the heart. Teeth P reflects the process of depolarization of both atria, complex QRS.- Depolarization of both ventricles, and its duration is the total duration of this process. Segment St. And the tooth g corresponds to the phase of ventricular repolarization. Duration of interval PQ. Determined by the time for which the initiation passes the atrium. The duration of the QR-ST is the duration of the "electric systole" of the heart; It may not correspond to the duration of mechanical systole.

The indicators of good heart training and large potential functionality of lactation development in highly productive cows are a small or average heart rate and high voltage of the ECG teeth. High heart rate with high voltage ECG - sign of high load on the heart and reduce its potential opportunities. Reducing the voltage of teeth R. and t, increase intervals P.- Q. and Q-associated to reduce the excitability and conductivity of the heart system and the low functional activity of the heart.

ECG elements and principles of its overall analysis

- The method of registration of the potential difference of the electric dipole of the heart in certain parts of the human body. When the heart is excited, an electrical field occurs, which can be registered on the body surface.

Vector Vector - The method of studying the magnitude and direction of the integral electric heap vector during the cardiac cycle, the value of which is continuously changing.

Teleelectrocardiography (electro-electro-electronicardiography Electrotelekardiography) - The method of registration of an ECG, in which the recording device is significantly removed (from several meters to hundreds of thousands of kilometers) from the person being examined. This method is based on the use of special sensors and receiving and transmitting radio facilities and is used when it is impossible or undesirable to carry out conventional electrocardiography, for example, in sports, aviation and space medicine.

Halter monitoring - Daily monitoring of ECG, followed by rhythm analysis and other electrocardiographic data. Daily monitoring of the ECG along with a large volume of clinical data allows you to identify the variability of the rhythm of the heart, which in turn is an important criterion for the functional state of the cardiovascular system.

Balleriography - The method of registration of human body microcolebans caused by throwing blood from the heart during systole and blood movement along large veins.

Dynamocardiography - The method of registration of the bias of the center of gravity of the chest, due to the movement of the heart and moving the mass of blood from the cavities of the heart into the vessels.

Echocardiography (ultrasound cardiography) - The method of studying the heart, based on the recording of ultrasound oscillations, reflected from the surfaces of the walls of the ventricles and the atria at the border of them with blood.

Auscultation - The method of assessing sound phenomena in the heart on the surface of the chest.

Phonocardiography - The method of graphic registration of the heart tones from the surface of the chest.

Angiocardiography - X-ray method for studying the cavities of the heart and mainstream vessels after their catheterization and administration to the blood of radiocontrase substances. A variety of this method is Coronaryography -x-ray-contrast study directly from heart vessels. This method is the "gold standard" in the diagnosis of ischemic heart disease.

Reward - Method for studying the blood supply to various organs and tissues based on registration of changes in the complete electrical resistance of tissues when the electric current of high frequency and low force passes through them.

ECG is represented by teeth, segments and intervals (Fig. 2).

Teeth R. In normal conditions, characterizes the initial events of the heart cycle and is located on the ECG to the teeth of the ventricular complex QRS.. It reflects the dynamics of atrial myocardium. Teeth R Symmetrical, has a flattened vertex, its amplitude is maximum in the second allocation and is 0.15-0.25 mV, the duration is 0.10 s. The ascending part of the teeth reflects the depolarization of predominantly myocardium of the right atrium, descending - left. In the norm of the proven R Positive in most devices, negative in the assignment aVR., in III I. V1. He may be two-phase leads. Changing the usual location of the prison Ron ECG (in front of the complex QRS.) observed with heart arrhythms.

The processes of repolarization of the myocardium atrial on the ECG are not visible, as they are superimposed on higher-permpludes of the QRS complex.

IntervalPQ. Measured from the beginning of the teeth R before the start of the priest Q.. It reflects the time passing from the beginning of the initiation of the atria prior to the start of the excitation of ventricles or other in words, time spent on carrying out excitation on the conductive system to the myocardium of ventricles. Its normal duration is 0.12-0.20 ° C and includes the time of the atro-ventricular delay. Increase the duration of the interval PQ.more than 0.2 C may indicate a violation of the excitation in the field of an atrioventricular node, a beam of the His or its legs and is interpreted as evidence of the presence of a person's signs of the blockade of the 1st degree. If an adult has an interval PQ. Less than 0.12 s, then this may indicate the existence of additional ways to excite between atrial and ventricles. Such people have the danger of developing arrhythmias.

Fig. 2. Normal values \u200b\u200bof ECG parameters in II Decommission

Teeth complex QRS. Reflects the time (normally 0.06-0.10 c) during which the structure of the myocardial structure of ventricles is consistently involved in the excitation process. At the same time, the papillary muscles and the outer surface of the interventricular partition are first excited (the tooth occurs Q. The duration of up to 0.03 c), then the bulk of the myocardial of the ventricles (the tooth duration is 0.03-0.09 (c) and the recently of the myocardium base and the outer surface of the ventricles (Teeth 5, duration up to 0.03 s). Since the mass of myocardium left ventricle is significantly more than the mass of the right, then changes in electrical activity, it is in the left ventricle, dominated in the ventricular complex of the ECG teeth. Since the complex QRS. reflects the process of depolarization of the powerful mass of the myocardial of ventricles, then the amplitude of the teeth QRS.usually higher than the amplitude of the teeth R, reflecting the process of depolarization relative to a small mass of the myocardium atrial. Tota amplitude R. fluctuates in different leads and can reach up to 2 mV in I, II, III and in AVF. leads; 1.1 mV B. aVL.and up to 2.6 mV in left chest leads. Teeth Q.and S.in some leads may not appear (Table 1).

Table 1. Borders of normal values \u200b\u200bof the amplitude of the ECG teeth in the second standard assignment

ECG Teeth	Minimum standards, mV	Maximum norm, mV

SegmentSt.registered after the complex ORS.. It is measured from the end of the teeth S.before the start of the priest T.At this time, all myocardial and left ventricles are in a state of excitation and the potential difference between them virtually disappears. Therefore, the entry on the ECG becomes almost horizontal and isoelectric (the deviation of the segment is allowed St.from an isoelectric line no more than 1 mm). Bias St.a large amount may be observed in myocardial hypertrophy, with severe physical exertion and indicates insufficiency of blood flow in the ventricles. Significant deviation St.from the isoline, registered in several ECG leads, may be a precursor or evidence of the help of myocardial infarction. Duration St.in practice, it is not estimated, since it significantly depends on the frequency of heart cuts.

Teeth T.reflects the process of ventricular repolarization (duration - 0.12-0.16 c). The amplitude of the tissue T is very variable and should not exceed 1/2 amplitude of the teeth R.. Teeth g is positive in those responsibilities in which a significant amplitude of the prong is written R.. In leads in which the teeth R.low amplitude or not detected, negative prong can be registered T. (Head AVR.and vi).

IntervalQt.reflects the duration of the "electric stomach electrical systole" (time from the beginning of their depolarization until the end of the repolarization). This interval is measured from the beginning of the teeth. Q.to the end of the teeth T.Normally, it has a duration of 0.30-0.40 s. Duration of interval FROM Depends on the heart rate, the tone of the autonomous nervous system centers, hormonal background, the actions of some medicinal substances. Therefore, the change in the duration of this interval is monitored to prevent overdose of some hearty drugs.

TeethU. It is not a permanent ECG element. It reflects the trace electrical processes observed in myocardium of some people. Diagnostic value did not receive.

An ECG analysis is based on an assessment of the presence of teeth, their sequences, directions, shapes, amplitudes, measuring the duration of teeth and intervals, position relative to the insulance and calculation of other indicators. According to the results of this assessment, make a conclusion about the frequency of heart abbreviations, the source and correctness of the rhythm, the presence or absence of signs of myocardial ischemia, presence or absence of signs of myocardial hypertrophy, the direction of the electrical axis of the heart and other heart function indicators.

For the correct measurement and interpretation of ECG indicators, it is important that it be qualitatively recorded under standard conditions. Qualitative is such an ECG record on which no noise and offset of the recording level from horizontal and comply with the standardization requirements. The electrocardiograph is an amplifier of biopotentials and to install a standard gain coefficient on it, when the supply of a calibration signal of a calibration signal in 1 mV leads to a deviation of the recording from a zero or isoelectric line by 10 mm. Compliance with the gain allows you to compare ECG recorded on any types of instruments, and express the amplitude of the ECG teeth in millimeters or malelvolts. To correctly measure the duration of the teeth and the ECG intervals, the record must be made at a standard speed of the diagram paper, a writing device or a sweep speed on the monitor screen. Most modern electrocardiographs will provide an opportunity to register the ECG at three standard speeds: 25, 50 and 100 mm / s.

After checking visually the quality and compliance with the requirements of the standardization of ECG recording, proceed to the evaluation of its indicators.

The amplitude of the teeth is measured by taking the reference point isoelectric, or zero, line. The first is registered in the case of the same potential difference between the electrodes (PQ - from the end of the PC to the beginning Q, the second - in the absence of the potential difference between the discharge electrodes (TP interval)). Teeth, directed up from isoelectric line, are called positive downwards - negative. The segment is called the ECG site between the two teeth, the interval is a plot that includes a segment and one or several teeth adjacent to it.

According to the electrocardiogram, it can be judged by the location of the excitation in the heart, the sequence of coverage of the heart departments by excitation, the rate of excitation. Therefore, one can judge the excitability and conductivity of the heart, but not about the contractility. In some diseases of the heart, a disunity between the excitation and reduction of the heart muscle may occur. In this case, the pumping function of the heart may be absent in the presence of the registered biopotentials of myocardium.

RR interval

The duration of the cardiac cycle is determined by the interval RR, which corresponds to the distance between the vertices of the neighboring teeth R.. Due magnitude (normal) interval Qt.calculate using the Basiett formula:

where To -a coefficient equal to 0.37 for men and 0.40 for women; RR - The duration of the heart cycle.

Knowing the duration of the heart cycle, it is easy to calculate the heart rate frequency. To do this, it is enough to divide the time interval 60 s on the average size of the interval duration RR.

Comparing the duration of the range of intervals RRyou can make a conclusion about the correctness of the rhythm or the presence of arrhythmias in the work of the heart.

A comprehensive analysis of standard ECG assignments makes it also to identify signs of insufficiency of blood flow, exchange disorders in the heart muscle and diagnose a number of heart disease.

Tones of the heart- Sounds arising during systole and diastoles are a sign of the presence of heart abbreviations. Sounds generated by a working heart can be investigated by auscultation method and register the method of phonor cardiography.

An auscccuity (listening) can be carried out directly by the ear attached to the chest, and with the help of tools (stethoscope, phonenadoscope), reinforcing or filtering sound. With auscultation, two tones are well heard: I tone (systolic), which occurs at the beginning of the ventricular systole, II tone (diastolic) arising at the beginning of the diastole of the ventricles. The first tone with auscultation is perceived lower and extended (represented by frequencies of 30-80 Hz), the second - higher and short (represented by frequencies of 150-200 Hz).

The formation of the I tone is due to sound oscillations caused by slamming the waves of the AV valve, the shake of the linked tendral threads during their tension and the reduction of the myocardium of ventricles. Some contribution to the origin of the last part of the I tone can be discovered by semi-lunged valves. The most clearly, the tone is heard in the region of the top of the heart (usually in the 5th inter estreon on the left, by 1-1.5 cm left the midcularity line). Listening to his sound at this point is particularly informative to estimate the state of the mitral valve. To estimate the state of the three-risk valve (overlapping the right AV-hole) more informatively listening to 1 tone at the base of the sword-shaped process.

The second tone is better listened to the 2nd inter estreon on the left and to the right of the sternum. The first part of this tone is due to the slam of the aortic valve, the second - valve of the pulmonary barrel. Left is better listening to the sound of the pulp of the pulp, and the right is the aortic valve.

In the pathology of the valve apparatus, an aperiodic sound oscillations arise during the heart, which create noises. Depending on which valve is damaged, they are superimposed on a certain tone of the heart.

A more detailed analysis of sound phenomena in the heart is possible but recorded phonocardiogram (Fig. 3). To register phonocardiograms, an electrocardiograph is used complete with a microphone and an amplifier of sound oscillations (phonocardiographic prefix). The microphone is installed in the same points of the body surface, in which AU-Socialization is conducted. For a more reliable analysis of the tones and sound noise, the phocardiogram is always recorded simultaneously with the electrocardiogram.

Fig. 3. Synchronously recorded ECGs (top) and phonocardogram (bottom).

On the phonocardiogram, in addition to I and II tones, III and IV tons can be registered, usually not listened to the ear. The third tone appears as a result of vibrations of the wall of the ventricles during their rapid filling during the diastole phase of the same name. The fourth tone is registered during the atrium systole (presets). The diagnostic value of these tones is not defined.

The occurrence of Tone I in a healthy person is always recorded at the beginning of the ventricular systole (voltage period, the end of the asynchronous reduction phase), and its full registration coincides with the recording of the ECG of the ventricular complex QRS.. The initial small-scale low-frequency fluctuations in the amplitude (Fig. 1.8, a) are sounds arising when cutting the myocardium of ventricles. They are recorded almost simultaneously with Q tooth q to the ECG. The main part of the Tone I, or the main segment (Fig. 1.8, b), is represented by high-frequency sound fluctuations in large amplitudes arising from the closure of the AV valve. The beginning of the registration of the main part of the I Tone is late for 0.04-0.06 from the start of the teeth Q. on ECG (Q.- I tone in fig. 1.8). The final part of the Tone I (Fig. 1.8, c) is the amplitude of the amplitude sound oscillations arising from the opening of the aortic valves and the pulmonary artery and sound vibrations of the aortic walls and the pulmonary artery. Duration I Tone - 0.07-0.13 s.

The beginning of the second tone under normal conditions coincides in time with the beginning of the ventricular diastole, late at 0.02-0.04 seconds to the end of the teeth. The tone is represented by two groups of sound oscillations: the first (Fig. 1.8, a) is caused by the closure of the aortic valve, the second (P in Fig. 3) is the closure of the pulmonary artery valve. Duration of Tone II - 0.06-0.10 s.

If the ECG elements are judged by the dynamics of electrical processes in myocardium, then on elements of phonocardiograms - about mechanical phenomena in the heart. The phocardiogram represents information about the status of the heart valves, the beginning of the phase of isometric reduction and relaxation of ventricles. By the distance between I and II tone determine the duration of "mechanical systole" of ventricles. An increase in the amplitude of the second tone may indicate increased pressure in the aorta or pulmonary trunk. However, at present, more detailed information on the status of valves, the dynamics of their opening and closing and other mechanical phenomena in the heart is obtained with ultrasound examination of the heart.

Ultrasound of the heart

Ultrasound examination (ultrasound) of the heart, or echocardiography, It is an invasive method of studying the dynamics of changes in the linear dimensions of the morphological structures of the heart and blood vessels, allowing to calculate the speed of these changes, as well as changes in the volume of heart and blood cavities in the process of making a heart cycle.

The method is based on the physical property of the sounds of high frequency in the range of 2-15 MHz (ultrasound) passing through liquid media, body tissues and hearts, while reflected from the boundaries of any changes in their density or from the borders of the separation of organs and tissues.

Modern ultrasonic (UZ) Echocardiograph includes blocks such as an ultrasound generator, a Uz-emitter, a receiver of reflected ultrasonic waves, visualization and computer analysis. The emitter and receiver of the Ultra are constructively combined in a single device, called a Uz-sensor.

Echocardiographical study is carried out by sending from the sensor inside the body at certain directions of short series of ultrasound-waves generated by the instrument. Part of the ultrasonic waves, passing through the body tissues, absorbs, and reflected waves (for example, from the surfaces of the myocardium and blood section; valves and blood; walls of blood vessels and blood), spread in the opposite direction to the body surface, are collected by the sensor receiver and are converted to Electrical signals. After computer analysis of these signals, a Uz-image of the dynamics of mechanical processes occurring in the heart during the heart cycle is formed on the display screen.

According to the results of the calculation of the distances between the working surface of the sensor and the surfaces of the sections of various tissues or changes in their density, many visual and digital echocardiographic performance indicators can be obtained. Among these indicators, the dynamics of changes in the size of the cavities of the heart, the size of the walls and partitions, the positions of valve sfing, the size of the internal diameter of the aorta and large vessels; identifying the presence of seals in the tissues of the heart and vessels; The calculation of the finite-diastolic, finite systolic, shock volumes, the ejection fraction, the speed of the blood and the blood of the heart cavities, etc. Ultrasound of the heart and blood vessels is currently one of the most common, objective methods for assessing the state of the morphological properties and the pump function of the heart.

Electrocardiogram (ECG) - recording the electrical activity of the cells of the heart muscle at rest. Professional ECG analysis allows you to estimate the functional condition of the heart and identify most of the heart pathologies. But some of them do not show this study. In such cases, additional research is appointed. So, hidden pathology can be detected when removing the cardiogram on the background of the load test. Even more informative Holter monitoring - removal of the 24-hour cardiogram, as well as echocardiography.

In what cases is appointed ECG

Cardiologist issues a direction if the patient has the following primary complaints:

pain in the heart, back, chest, belly, neck;
swelling on the legs;
dyspnea;
fainting;
interruptions in the heart of the heart.

With the sudden appearance of sharp pain in the heart area, you should immediately remove the ECG!

Regular removal of the cardiogram is considered mandatory with such diagnosed diseases:

transferred heart attack or stroke;
hypertension;
diabetes;
rheumatism.

In mandatory, the ECG is carried out in preparation for operations, monitoring pregnancy, with a medical examination of pilots, chauffeurs, sailors. The result of the cardiogram is often required when making a ticket to sanatorium treatment and issuing permits for active sports activities. In preventive purposes, even in the absence of complaints, it is recommended to remove ECG every year, especially people over 40 years old. Often it helps to diagnose asymptomatic diseases.

Heart without tired worries all his life. Take care of this amazing organ without waiting for his complaints!

What Shows ECG

Visually, the cardiogram shows a combination of teeth and recession. The teeth are consistently denoted by letters P, Q, R, S, T. Analyzing the height, width, the depth of these teeth and the duration of the intervals between them, the cardiologist is an idea of \u200b\u200bthe state of different parts of the heart muscle. So, the first prong P contains information about the work of the atrium. The following 3 teeth reflect the process of excitation of ventricles. After the Tusk T comes a period of relaxation of the heart.

Example ECG fragment with normal sinus rhythm

The cardiogram allows you to determine:

heart rate (heart rate);
cardiac rhythm;
various types of arrhythmias;
various types of conduction blockade;
myocardial infarction;
ischemic and cardiodistrophic changes;
wolf Parkinson-White (WPW) syndrome;
hypertrophy of ventricles;
position of the electrical axis of the heart (EOS).

Diagnostic value of ECG parameters

Heart rate

The heart of the adult is normal reduced from 60 to 90 times in min. With a smaller value, bradycardia is determined, and with larger - tachycardia, which is not necessarily pathology. Thus, significant bradycardia is characterized by trained athletes, especially runners and skiers, and transient tachycardia is quite normal in spiritual experiences.

In healthy adults, the pulse frequency corresponds to the heart rate and is equal to 60 -90 per 1 minute

Heartbeat

Normal heart rhythm is called regular sinus, i.e., the heart-generated in the sinus node. Nonsenus generation of pathological, and irregularity indicates one of the types of arrhythmia.

During the removal of the patient's ECG, they ask to delay their breath in order to reveal the possible pathological characteristic arrhythmia. A serious problem is flickering arrhythmia (atrial flicker). With it, the generation of heart pulses occurs not in the sinus node, but in atrial cells. As a result, atrium and ventricles are reduced chaotic. This contributes to thrombosis and creates a real threat to a heart attack and stroke. To prevent them, life antiarrhythmic and antithrombotic therapy is prescribed.

Cleaning arrhythmia is a rather frequent disease in old age. It may be asymptomatic, but to create a real threat to health and life. Watch your heart!

The arrhythmia includes the extrasystole. The extrasystole is an abnormal reduction in the heart muscle under the influence of an excess electrical pulse that does not emanate from the sinus node. Distinguished atrial, ventricular and atrioventricular extrasystole. What types of extrasystole require interference? Single functional extrasystoles (usually atrial) often occur at a healthy heart against the background of stress or excessive physical exertion. Potentially dangerous include group and frequent ventricular extrasystoles.

Blocada

Atrioventricular (A-V) blockade is called a violation of the conductivity of electrical pulses from the atria to the ventricles. As a result, they are reduced incomprehensible. With a-V blockade, as a rule, treatment is required, and in difficult cases - installation of the pacemaker.

Violation of the conduction inside myocardium is called the blockade of the Gis beam legs. It can be localized on the left or right leg or on both together and be partial or complete. With this pathology, conservative treatment is shown.

The synoyatrial blockade is a conduction defect from the sinus node to myocardium. This type of blockade arises with other heart diseases or in the overdose of drugs. Requires conservative treatment.

Myocardial infarction

Sometimes ECG reveals myocardial infarction - necrosis of the heart muscle site due to the cessation of its blood circulation. The cause can be large atherosclerotic plaques or a sharp spasm of vessels. The type of heart attack is distinguished by the degree of lesion - small-scale (non-Q-infarction) and extensive (transmural, q-infarction) species, as well as localization. Detection of signs of heart attack involves urgent hospitalization of the patient.

ECG with myocardial infarction

The detection on the cardiogram of the scars testifies to the myocardial infarction suffered once, possibly a non-barreling and unnoticed patient.

Ischemic and dystrophic changes

Heart ischemya is called oxygen starvation of its various sections due to insufficient blood supply. The detection of such pathology requires the appointment of anti-chemical drugs.

Dystrophic is called metabolic disorders in myocardium, not related to circulatory disorders.

Wolf Parkinson-White Syndrome

This innate disease is in existence in myocardium anomalous conductivity paths. If this pathology causes arrhythmic attacks, then treatment is necessary, and in severe cases, surgical intervention.

Hypertrophy of ventricles is an increase in the size or thickening of the wall. Most often hypertrophy - a consequence of heart defects, hypertension, pulmonary diseases. Does not have an independent diagnostic value and the position of the EOS. In particular, the hypertension determines the horizontal position or deviation to the left. Masives and complex. Thrust people are usually the position of the EOS - vertical.

ECG features in children

For children under the age of year, it is considered normal tachycardia to 140 strokes in min., HCH fluctuations when removing an ECG, incomplete blockade of the right leg of a beam of Gis, vertical EOS. At the age of 6 years, the heart rate is allowed to 128 shots in min. Respiratory arrhythmia is characteristic of age from 6 to 15 years.

Registration of an electrocardiogram is a method for studying electrical signals formed during muscle activity. To fix the data of the electrocardiogram, 10 electrodes are used: 1 zero on the right leg, 3 standard from the limbs and 6 in the heart area.

The consequence of the removal of electrical indicators, the works of various parts of the organ, the creation of an electrocardiogram becomes.

Its parameters are written on a special roll paper. The speed of the paper movement is presented in 3 versions:

25 mm.
50 mm second;
100 mm;

There are electronic sensors that can record the ECG parameters on the hard disk of the system unit and, if necessary, output this data on the monitor or print on the required paper formats.

Decoding recorded electrocardiogram.

It gives the result of the analysis of the parameters of the electrocardiogram specialist cardiologist. The registration of the recording is conducted by the doctor by establishing the duration of the intervals between different elements of fixed indicators. The explanation of the features of the electrocardiogram contains many points:

Normal ECG indicators.

Consideration of the standard heart cardiogram is represented by the following indicators:

Electrocardiogram in the event of heart attack cardiac muscle.

Myocardial infarction arises due to the exacerbation of ischemic illness, when the inner cavity of the coronary artery of the heart muscle is significantly narrowed. If for 15 to 20 minutes, it does not fix the specified violation, the death of muscle cells of the hearts resulting from oxygen and nutrients from this artery occurs. This circumstance creates significant violations in the functioning of the heart and turns out to be a severe and serious threat to life. If the heart rate occurs, the electrocardiogram will help reveal the place of necrosis. The specified cardiogram contains noticeably manifested deviations of electrical signals of the heart muscle:

Heart rhythm disorder.

The rhythm disorder reduction of heart muscles is detected when shifts on the electrocardiogram appear:

Hypertrophy of the heart departments.

The increase in the volume of heart muscles is the adaptation of the body to new conditions of operation. The changes appearing on the electrocardiogram are determined by the high bioelectric force, the characteristic portion of the muscles, the delay in the movement of bioelectric pulses in its thicker, the appearance of signs of oxygen starvation.

Conclusion.

Electrocardiographic indicators of heart pathology are diverse. Their reading complex activities in which special training and improvement of practical skills are needed. A specialist characterizing the ECG, it is necessary to know the main positions of heart physiology, various versions of the cardiogram. He needs to have skills in the ability to identify the abnormalities of the heart. To calculate the effects of drugs and other factors, on the emergence of differences, in the structure of the teeth and the ECG gaps. Therefore, the decoding of the electrocardiogram should be entrusted to a specialist who came across his practice with various deficiencies in the work of the heart.

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Electrocardiography is a method of graphic registration of the potential difference of the electric field of the heart arising from its activities. Registration is made with the help of an electrocardiograph. It consists of an amplifier that allows you to catch the currents of very low voltage; a galvanometer measuring the amount of voltage; power systems; recording device; Electrodes and wires connecting the patient with the device. The recorded curve is called an electrocardiogram (ECG). Registration of the difference in the potentials of the electric field of the heart from two points of the body surface is called the assignment. As a rule, the ECG is recorded in twelve leads: three - two-pole (three standard leads) and nine - single-pole (three single-pole reinforced leads from the limbs and 6 single-pole infants). With bipolar leads, two electrodes are connected to the electrocardiograph, with single-pole leads, one electrode (indifferent) is combined, and the second (differential, active) is placed in the selected point of the body. If the active electrode is placed on the limb, the lead is called single-pole, reinforced from the limb; If this electrode is placed on the chest - a single-pole inference.

To register an ECG in standard leads (I, II and III), climbing napkins, moistened with saline, are imposed on the limbs, which are placed metal plates of electrodes. One electrode with a red wire and one embossed ring is placed on the right, the second - with a yellow wire and two embossed rings - on the left forearm and the third - with a green wire and three embossed rings - on the left shin. To record allocations to the electrocardiograph, two electrodes are connected to the electrocardiograph. For recording I, the leads are connected to the electrodes of right and left hands, the II of the lead - the electrodes of the right hand and the left leg, the III of the lead - the electrodes of the left hand and the left leg. Switching assignments is made by turning the handle. In addition to the standard, single-pole reinforced leads are removed from the limbs. If the active electrode is located on the right hand, the lead is indicated as AVR or UE, if on the left hand - AVL or UL, and if on the left foot - AVF or UN.

Fig. 1. The location of the electrodes when registering the front breasts (indicated by the numbers corresponding to their sequence 1 numbers). Vertical stripes crossing numbers correspond to the anatomical lines: 1 - right sneaker; 2 - left sternum; 3 - left okolaudine; 4-left media removal; 5-leaved front axillary; 6 - left medium axillary.

When registering single-pole infants, the active electrode is placed on the chest. ECG is registered in the following six positions of the electrode: 1) at the right edge of the sternum in the IV intercostal; 2) at the left edge of the sternum in the IV intercostal; 3) on the left side of the line between IV and V intercostalines; 4) in the middle-heartful line in the V inter estreon; 5) on the anterior axillary line in the V inter estreon and 6) for the middle axillary line in the V inter estreon (Fig. 1). Single-pole breasts are denoted by the Latin letter V or Russians. Less frequently register bipolar breasts, at which one electrode was located on the chest, and the other on his right hand or left leg. If the second electrode was located on the right hand, the breasts were denoted by Latin CR letters or Russians - GP; At the location of the second electrode on the left leg, the breasts were denoted by Latin CF letters or Russians - GG.

ECG of healthy people is distinguished by variability. It depends on age, physique, etc. However, in the normal normal, certain teeth and intervals can always be distinguished on it, reflecting the sequence of excitation of the heart muscle (Fig. 2). According to the available time stamp (on the photo paper, the distance between two vertical stripes is 0.05 seconds, on millimeter paper with a period of 100 mm / s 1 mm equal to 0.02 seconds, at a speed of 25 mm / s - 0.04 sec. ) You can calculate the duration of the teeth and intervals (segments) of the ECG. The height of the teeth is compared with the standard marker (when the pulse is applied to the pulse, the recorded line must deviate from the initial position by 1 cm). The arousal of myocardia begins with atrium, and the ECG appears at the SERVICE R. Normally, it is small: a height is 1-2 mm and a duration of 0.08-0.1 seconds. The distance from the start of the P to the tooth q (interval P-Q) corresponds to the time of propagation of excitation from the atria to the ventricles and is 0.12-0.2 sec. During the excitation of ventricles, the QRS complex is recorded, and the magnitude of its teeth in different leads is expressed differently: the duration of the QRS complex is 0.06- 0.1 s. The distance from the teeth s to the start of the T - segment S-T, is normal in normal levels with the interval of R-Q and the displacement should not exceed 1 mm. When the excitation of the excitation in the ventricles, T. Interval is recorded from the start of the q tooth to the end of the teeth of T reflects the process of excitation of ventricles (electrical systole). Its duration depends on the cardiac rhythm frequency: when the rhythm is increased, it is shortened, when slowing it - it is lengthened (on average it is equal to 0.24-0.55 seconds.). The heart rate frequency is easy to calculate the ECG, knowing how much time one cardiac cycle continues (the distance between two teeth R) and how many such cycles are contained per minute. The interval of T-P corresponds to the diastole of the heart, the device at this time records the direct (so-called isoelectric) line. Sometimes, after the teeth, the teeth u is registered, the origin of which is not quite clear.

Fig. 2. Electrocardiogram of a healthy person.

In pathology, the magnitude of the teeth, their duration and direction, as well as the duration and location of the intervals (segments) of the ECG, can change significantly, which gives the basis to use electrocardiography in the diagnosis of many diseases of the heart. With the help of electrocardiography, various heart rate disorders are diagnosed (see), inflammatory and dystrophic myocardial lesions are reflected on the ECG. Electrocardiography in the diagnosis of coronary insufficiency and myocardial infarction plays a particularly important role.

On ECG, it is possible to determine not only the presence of a heart attack, but also to find out which wall of the heart is amazed. In recent years, the method of teleelectrocardiography (electolectrocardiography), based on the principle of wireless transmission of the electric field of the heart, is used to study the potential difference of the electric field of the heart. This method allows you to register an ECG during exercise, in motion (among athletes, pilots, astronauts).

Electrocardiography (Greek. Kardia - Heart, Grapho - I write, write down) - The method of registration of electrical phenomena arising in the heart during its reduction.

The history of electrophysiology, and consequently, electrocardiography begins with the experience of Galvani (L. Galvani), who found electrical phenomena in the muscles of animals in 1791. Matteucci (S. Matteucci, 1843) set the presence of electrical phenomena in the cut-off heart. Dubois Reymond (E. Dubois-Reymond, 1848) proved that both nerves and muscles excited part of electronegative in relation to being alone. Kellikher and Muller (A. Kolliker, N. Muller, 1855), imposing a neuro-muscle drug frog on the cutting heart, consisting of a sedlicate nerve connected to the calf muscle, received a double abbreviation when cutting a heart: one at the beginning of systole and other (non-permanent ) At the beginning of the diastole. Thus, the electromotive force (EMF) of the nude heart was recorded for the first time. To register the EMF of the heart from the surface of the human body for the first time, Waller was managed (A. D. Waller, 1887) by means of a capillary electrometer. Waller believed that the human body is a conductor surrounding the source of EDS - heart; Different points of the human body have potentials of various values \u200b\u200b(Fig. 1). However, the recording of the heart EMF inaccurately reproduced its oscillations obtained by the capillary electrometer.

Fig. 1. The distribution scheme of isopotential lines on the surface of the human body caused by the electromotive power of the heart. The figures indicate the values \u200b\u200bof potentials.

The accurate entry of the heart of the heart from the surface of the human body is an electrocardiogram (ECG) - was produced by Einthoven (W. Einthoven, 1903) by means of a string galvanometer, built on the principle of apparatuses for receiving transatlantic telegrams.

According to modern ideas of cells of excitable tissues, in particular, myocardial cells are coated with a semi-permeable shell (membrane), permeable for potassium ions and impenetrable for anions. Positively charged potassium ions in excess in cells compared with the environment surrounding them are held on the outer surface of the membrane with negatively charged anions located on its inner surface, impenetrable for them.

Thus, on the shell of a living cell, a double electric layer occurs - the shell is polarized, and its outer surface is charged positively with respect to the internal content, charged negatively.

This transverse potential difference is resting potential. If the outer and inner sides of the polarized membrane attach microelectrodes, then the outdoor circuit occurs. The recording of the resulting potential difference gives a monophasic curve. In the occurrence of excitation of the membrane of the excited site, the semi-perception is lost, the depolarizes and the surface becomes electronegative. Register with two microelectrodes of the potentials of the outer and inner shell of the depolarized membrane also gives a monophasic curve.

Due to the potential difference between the surface of the excited depolarized portion and the surface of the polarized, which is at rest, the action current occurs - the action potential. When the excitement covers all muscle fiber, its surface becomes electronegative. The cessation of excitation causes a wave of repolarization, and the potential of the rest of the muscular fiber is restored (Fig. 2).

Fig. 2. Schematic representation of polarization, depolarization and cell repolarization.

If the cell is in a state of rest (1), then electrostatic equilibrium is noted on both sides of the cell membrane, which consists in the fact that the cell surface is electropositive (+) relative to its inner side (-).

The excitation wave (2) instantly disrupts this equilibrium, and the cell surface becomes electronegative with respect to its inner side; Such a phenomenon is called depolarization or, more correctly, inversion polarization. After the excitation passed throughout the muscular fiber, it becomes completely depolarized (3); The whole surface has the same negative potential. Such a new equilibrium does not continue long, since after the excitation wave, a repolarization wave (4) follows, which restores the polarization of the state of rest (5).

The process of excitation in the normal human heart - depolarization - is as follows. An arising in the sinus node located in the right atrium, the excitation wave is spread at a speed of 800-1000 mm in 1 sec. Lucky on the muscular beams first right, and then the left atrium. The duration of coverage by the excitation of both atrium 0.08-0.11 seconds.

The first 0.02 - 0.03 seconds. Only the right atrium was initiated, then 0.04 - 0.06 seconds - both at the sortia and the last 0.02 - 0.03 sec. - Only the left atrium.

Upon reaching an atri-ventricular node, the excitation spread slows down. Then, with a large and gradually increasing speed (from 1400 to 4000 mm in 1 sec.) It is directed along the Gisa beam, its legs, their branches and branching and reaches the end endings of the conductor system. Reaching contractile myocardium, excitation with a significantly reduced speed (300-400 mm in 1 sec.) Approaches both ventricles. Since the peripheral branches of the conductor system is scattered mainly under the endocardium, the inner surface of the heart muscle is excited earlier. The further progress of the excitation of the ventricles is not associated with the anatomical arrangement of muscle fibers, and is directed from the inner surface of the heart to the outer. The occurrence of excitation in muscle beams located on the surface of the heart (subepicarordial) is determined by two factors: the excitation time is the most closely located to these beams of branches of the conductor system and the thickness of the muscular layer separating subpicardial muscle bundles from the peripheral branches of the conductor system.

Previously, the interventricular partition and the right puffy muscle are excited. In the right ventricle, excitation first covers the surface of its central part, since the muscle wall in this place is thin and its muscle layers closely come into contact with the peripheral branches of the right leg of the conductor system. In the left ventricle, it first comes to the excitation of the top, as the wall separating it from the peripheral branches of the left leg, thin. For different points of the surface of the right and left ventricles of normal heart, the excitation period occurs in a strictly defined time, and most of the fibers on the surface of the thin-walled right ventricle and only a small amount of fibers on the surface of the left ventricle due to their proximity to the peripheral branchings of the conductor system (rice . 3).

Fig. 3. A schematic representation of the normal excitation of the interventricular septum and the outer walls of the ventricles (according to Sodi-Palyarez from Sot.). The excitation of ventricles begins on the left side of the partition in the middle part of it (0.00- 0.01 seconds) and then can reach the base of the right nobility muscle (0.02 sec.). After that, subendocardial muscular layers of the outer wall of the left (0.03 seconds) and the right (0.04 seconds) of the ventricles are excited. The latter are excited by the basal parts of the external walls of the ventricles (0.05-0.09 seconds).

The process of stopping the excitation of muscle fibers of the heart - repolarization - can not be considered fully studied. The process of repolarization of the atrium coincides mostly with the process of depolarization of ventricles and partly with the process of their repolarization.

The process of repolarization of ventricles is much slower and in a slightly different sequence than the depolarization process. It is explained by the fact that the duration of the excitation of muscular beams of surface layers of myocardium is less than the duration of the excitation of subendocardial fibers and puffy muscles. The recording of the process of depolarization and repolarization of the atrial and ventricles from the surface of the human body and gives a characteristic curve - an ECG reflective electrical systole.

Heart EMF recording is currently produced by several other methods than Enthoven was registered. Enthovens registered the current obtained by connecting two points of the surface of the human body. Modern devices - electrocardiographs - register directly the voltage due to the electromotive power of the heart.

A stress caused by a heart equal to 1-2 mV is amplified by radiolmes, semiconductors or an electronolic tube up to 3-6 V, depending on the amplifier and the recording apparatus.

The sensitivity of the measuring system is set in such a way that the potential difference in 1 mV gives a deviation to 1 cm. The entry is made on the photo paper or a film or directly on paper (ink mills, with a thermal record, with a jet recording). The most accurate results are recorded on the photo paper or a film and the inkjet record.

To explain the peculiar ECG form, various theories of its origin were proposed.

A. F. Samoilov considered the ECG as a result of the interaction of two monophasic curves.

Considering that when registering with two microelectrodes of the outer and inner surface of the membrane, a monophase curve, M. T. Speaker, believes that the monophasic curve reflects the basic form of myocardial bioelectric activity. The algebraic sum of two monophasic curves gives ECG.

Pathological changes in ECG are due to the shifts of monophasic curves. This theory of ECG genes is called differential.

The outer surface of the cell membrane in the excitation period can be represented schematically as consisting of two poles: negative and positive.

Immediately before the excitation wave, anywhere in its propagation, the cell surface is the electropositive (polarization state at rest), and directly behind the excitation state of the cell surface is electronegative (depolarization state; Fig. 4). Data Electrical charges of opposite characters, grouping on the pairs from one and the other side of each place, covered by excitation wave, form electric dipoles (a). Repolarization also creates an innumerable amount of dipoles, but, unlike the above dipoles, the negative pole is located in front, and the positive pole is rear in relation to the direction of the wave propagation (b). If depolarization or repolarization is completed, the surface of all cells has the same potential (negative or positive); Diples are completely absent (see Fig. 2, 3 and 5).

Fig. 4. A schematic representation of electric dipoles during depolarization (A) and repolarization (b) arising from both sides of the excitation wave and waves of repolarization as a result of changes in the electrical potential on the surface of the myocardial fibers.

Fig. 5. Scheme of the equilateral triangle in Einthovenu, Faro and Warta.

Muscular fiber is a small bipolar generator producing a small (elementary) EDC - an elementary dipole.

At each moment, the systole of the heart takes depolarization and repolarization of a huge number of myocardial fibers located in different parts of the heart. The sum of the formed elementary dipoles creates an appropriate value of the heart of the heart at every moment of systole. Thus, the heart represents a single summary dipole, which changes its magnitude and direction during the heart cycle, but does not change the location of his center. The potential at various points of the surface of the human body has a different amount depending on the location of the total dipole. The potential sign depends on which direction from the line perpendicular to the axis of the dipole and spent through its center, this point is located on the side of the positive pole, the potential has a sign +, and on the opposite side - a sign.

Most of the time excitement of the heart, the surface of the right half of the body, the right hand, head and neck has a negative potential, and the surface of the left half of the body, both legs and the left hand is positive (Fig. 1). This is a schematic explanation of the ECG genesis according to the theory of dipole.

EMF of the heart during electrical systole varies not only its value, but also the direction; Consequently, it is a vector magnitude. The vector is represented by a segment of a straight line of a certain length, the size of which with certain data of the recording apparatus indicates the absolute value of the vector.

Arrow at the end of the vector indicates the direction of the heart of the heart.

Eating modes that arose simultaneously with separate heart fibers are summed up by the rule of the formation of vectors.

The total (integral) vector of two vectors located in parallel and directed in one direction is equal in the absolute amount of the amount of the components of its vectors and is directed to the same side.

The total vector of two vectors of the same magnitude, located in parallel and directed to the opposite sides, is 0. The total vector of two vectors aimed at each other at an angle equals the diagonal of the parallelogram constructed from the components of its vectors. If both vectors form a sharp angle, their total vector is directed towards the components of its vectors and more than any of them. If both vector form a stupid angle and, therefore, directed in the opposite sides, their total vector is directed towards the greatest vector and in short. An ECG vector analysis is to determine the spatial direction and the magnitude of the total EMF of the heart at any time of its excitation.