Protocol direct line to ECG. Signs of a normal ECG

An electrocardiogram (ECG) is a recording of the electrical activity of heart muscle cells at rest. Professional ECG analysis allows you to assess the functional state of the heart and identify most cardiac pathologies. But this study does not show some of them. In such cases, it is prescribed additional research. Thus, hidden pathology can be detected when taking a cardiogram against the background of a stress test. Holter monitoring is even more informative - taking a 24-hour cardiogram, as well as echocardiography.

In what cases is an ECG prescribed?

The cardiologist issues a referral if the patient has the following primary complaints:

• pain in the heart, back, chest, abdomen, neck;
• swelling in the legs;
• dyspnea;
• fainting;
• interruptions in heart function.

Upon sudden appearance sharp pain in the region of the heart, an ECG should be taken immediately!

Regular ECG recording is considered mandatory for the following diagnosed diseases:

• previous heart attack or stroke;
• hypertension;
• diabetes;
• rheumatism.

An ECG is mandatory when preparing for operations, monitoring pregnancy, and during a medical examination of pilots, drivers, and sailors. The result of the cardiogram is often required when applying for a ticket to sanatorium treatment and the issuance of permits for active sports activities. For preventive purposes, even in the absence of complaints, it is recommended to take an ECG annually for everyone, especially people over 40 years of age. Often this helps to diagnose asymptomatic heart disease.

The heart works tirelessly throughout life. Take care of this amazing organ without waiting for its complaints!

What does an ECG show?

Visually, the cardiogram shows a combination of peaks and troughs. The waves are sequentially designated by the letters P, Q, R, S, T. By analyzing the height, width, depth of these waves and the duration of the intervals between them, the cardiologist gets an idea of ​​the state of different parts of the heart muscle. Thus, the first P wave contains information about the functioning of the atria. The next 3 teeth reflect the process of excitation of the ventricles. After the T wave, a period of relaxation of the heart begins.

Example of an ECG fragment with normal sinus rhythm

A cardiogram allows you to determine:

• heart rate (HR);
• heart rate;
• various types of arrhythmias;
• various types of conduction blockades;
• myocardial infarction;
• ischemic and cardiodystrophic changes;
• Wolff–Parkinson–White (WPW) syndrome;
• ventricular hypertrophy;
• position of the electrical axis of the heart (EOS).

Diagnostic value of ECG parameters

Heart rate

The heart of an adult normally contracts from 60 to 90 times per minute. A lower value indicates bradycardia, and a higher value indicates tachycardia, which is not necessarily a pathology. Thus, significant bradycardia is characteristic of trained athletes, especially runners and skiers, and transient tachycardia is quite normal during emotional distress.

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

Heartbeat

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

During the ECG, the patient is asked to hold his breath in order to identify possible pathological non-respiratory arrhythmia. A serious problem is atrial fibrillation (atrial fibrillation). With it, the generation of cardiac impulses occurs not in the sinus node, but in the cells of the atria. As a result, the atria and ventricles contract chaotically. This promotes blood clots and creates a real threat of heart attack and stroke. To prevent them, lifelong antiarrhythmic and antithrombotic therapy is prescribed.

Atrial fibrillation is a fairly common disease in old age. It may be asymptomatic, but pose a real threat to health and life. Follow your heart!

Arrhythmia also includes extrasystole. An extrasystole is an abnormal contraction of the heart muscle under the influence of an extra electrical impulse that does not come from the sinus node. There are atrial, ventricular and atrioventricular extrasystole. What types of extrasystoles require intervention? Single functional extrasystoles (usually atrial) often occur in a healthy heart due to stress or excessive physical exertion. Potentially dangerous include group and frequent ventricular extrasystoles.

Blockades

Atrioventricular (A-V) block is a disorder in the conduction of electrical impulses from the atria to the ventricles. As a result, they contract asynchronously. A-V block usually requires treatment, and in severe cases, the installation of a pacemaker.

A conduction disorder within the myocardium is called bundle branch block. It can be localized on the left or right leg or on both together and be partial or complete. For this pathology, conservative treatment is indicated.

Sinoatrial block is a conduction defect from the sinus node to the myocardium. This type of blockage occurs with other heart diseases or with an overdose medicines. Requires conservative treatment.

Myocardial infarction

Sometimes an ECG reveals myocardial infarction - necrosis of a section of the heart muscle due to cessation of its blood circulation. The cause may be large atherosclerotic plaques or a sharp spasm of blood vessels. The type of infarction is distinguished by the degree of damage - small-focal (non-Q-infarction) and extensive (transmural, Q-infarction) types, as well as by localization. Detection of signs of a heart attack requires urgent hospitalization of the patient.

ECG for myocardial infarction

The detection of scars on the cardiogram indicates a myocardial infarction that was once suffered, possibly painless and unnoticed by the patient.

Ischemic and dystrophic changes

Cardiac ischemia is oxygen starvation of its various parts due to insufficient blood supply. Detection of such a pathology requires the prescription of anti-ischemic drugs.

Dystrophic disorders are metabolic disorders in the myocardium that are not associated with circulatory disorders.

Wolff–Parkinson–White syndrome

This is a congenital disease consisting of the existence of abnormal conduction pathways in the myocardium. If this pathology causes arrhythmic attacks, then treatment is necessary, and in severe cases - surgical intervention.

Ventricular hypertrophy is an increase in size or thickening of the wall. Most often, hypertrophy is a consequence of heart defects, hypertension, and pulmonary diseases. The position of the EOS has no independent diagnostic value. In particular, with hypertension, a horizontal position or deviation to the left is determined. Build also matters. In thin people, as a rule, the position of the EOS is vertical.

Features of ECG in children

For children under the age of one year, tachycardia up to 140 beats per minute, fluctuations in heart rate when taking an ECG, incomplete blockade of the right bundle branch, and vertical EOS are considered normal. At the age of 6 years, a heart rate of up to 128 beats per minute is acceptable. Respiratory arrhythmia is typical for ages from 6 to 15 years.

MINISTRY OF HEALTH OF THE RF

NIZHNY NOVGOROD STATE

MEDICAL INSTITUTE

A.V. SUVOROV

Publishing house NGMI NIZHNY NOVGOROD, 1993

Kyiv – 1999

UDC 616.12–008.3–073.96

Suvorov A.V. Clinical electrocardiography. – Nizhny Novgorod

genus. Publishing House of NMI, 1993. 124 p. Ill.

Suvorov A. V.'s book is a good, complete textbook for cardiologists, therapists and senior students of medical institutes in all sections of electrocardiography. The features of ECG recording, normal ECG in standard and unipolar leads, all types of atrioventricular blockades, blockade of the legs of the His bundle, ECG features in hypertrophies, conduction disorders, arrhythmias, myocardial infarction, coronary artery disease, thromboembolism, cerebrovascular accidents, etc. are described in detail.

Published by decision of the editorial and publishing council of NMI

Scientific editor Professor S. S. BELOUSOV

Reviewer Professor A. A. OBUKHOVA

ISBN 5-7032-0029-6

© Suvorov A.V., 1993

PREFACE

Electrocardiography is one of the informative and most common methods of examining patients with heart disease. ECG also makes it possible to diagnose diseases and syndromes that require emergency cardiac care, and above all myocardial infarction, paroxysmal tachyarrhythmias, conduction disorders with Morgagni–Edams–Stokes syndrome, etc. The need for their diagnosis arises at any time of the day, but, unfortunately, the interpretation of the ECG presents significant difficulties for many doctors, and the reason for this is poor study method at the institute, the lack of courses on ECG diagnostics at the faculties of advanced training for doctors. It is very difficult to acquire literature on clinical electrocardiography. The author sought to fill this gap.

The manual on electrocardiography is structured traditionally: first, the electrophysiological foundations of electrocardiography are briefly outlined, the section on normal ECG in standard, unipolar and chest leads is presented in detail, electrical position hearts. The section “ECG for myocardial hypertrophy” describes general signs and criteria for atrial and ventricular hypertrophy.

When describing rhythm and conduction disorders, the pathogenetic mechanisms of the development of syndromes are presented, clinical manifestations and medical tactics.

The sections on ECG diagnosis of coronary artery disease, especially myocardial infarction, as well as infarction-like diseases, which are of great importance for practice, are covered in detail.

For complex ECG syndromes, a diagnostic search algorithm has been developed to facilitate the diagnosis of pathology.

The book is intended for doctors who want to study the theory and practice of this important area of ​​cardiology on their own or with the help of a teacher in a short time.

1. TECHNIQUE FOR REMOVING ELECTROCARDIOGRAM

The electrocardiogram is recorded using electrocardiographs. They can be single-channel and multi-channel. All electrocardiographs (Fig. 1) consist of an input device (1), an amplifier of cardiac biopotentials (2) and a recording device (3).

The input device is a lead switch with cables of different colors extending from it.

The amplifiers have a complex electronic circuit that allows them to enhance the biopotentials of the heart several hundred times. The power source for the amplifier can be batteries or AC power. For safety reasons when working with an electrocardiograph and to prevent interference, the device must be grounded using a wire, one end of which is attached to a special terminal of the electrocardiograph, and the other to a special circuit. If this is not available, in emergency cases, central heating water pipes can be used for grounding (as an exception).

The recording device converts electrical vibrations into mechanical ones. Mechanical pen recording is carried out using ink or carbon paper. Recently, thermal recording has become widespread.

The point is that a feather heated by electric current melts the fusible layer of the tape, exposing the black base.

To record an ECG, the patient is placed on a couch. To obtain good contact, gauze pads moistened with saline are placed under the electrodes. Electrodes are applied to the inner surfaces of the lower third of the upper and lower extremities, a red cable is connected to the right hand, a black cable (patient grounding) is connected to right leg, yellow - to the left hand and green cable - to the left lower limb. A pear-shaped chest electrode with a suction cup is connected to a white cable and installed in certain positions on the chest.

ECG recording begins with a reference millivolt, which should be equal to 10 mm.

IN 12 leads are mandatory recorded - three standard, three unipolar and six chest leads, III, avF leads, it is desirable to remove in the inspiratory phase. Additional leads are recorded according to indications.

IN each lead should record at least 5 QRS complexes, with arrhythmias one of the leads (II) is recorded on a long tape. The standard writing speed is 50 mm/s, with arrhythmias, a speed of 25 mm/s is used to reduce paper consumption. The voltage of the QRS complexes can be increased and decreased by 2 times, depending on the task of the study.

An application for an ECG study is written on a special form or in a journal, which indicates the full name, gender, blood pressure, age of the patient, diagnosis. It is imperative to report any medications you are taking.

therapy with cardiac glycosides, β-blockers. diuretics, electrolytes, antiarrhythmic drugs of the quinidine series, rauwolfia, etc.

2. ELECTROPHYSIOLOGICAL BASICS OF ELECTROCARDIOGRAPHY

The heart is a hollow muscular organ divided by a longitudinal septum into two halves: the left arterial and the right venous. The transverse septum divides each half of the heart into two sections: the atrium and the ventricle. The heart performs certain functions: automaticity, excitability, conductivity and contractility.

Automaticity is the ability of the conduction system of the heart to independently produce impulses. To the greatest extent the function

The sinus node (the center of first-order automaticity) has automaticity. At rest, it produces 60–80 impulses per minute. In case of pathology, the source of rhythm can be the atrioventricular node (the center of second-order automaticity); it produces 40–60 impulses per minute.

The conduction system of the ventricles (idioventricular rhythm) also has an automatic function. However, only 20–50 impulses are generated per minute (third-order center of automaticity).

Excitability is the ability of the heart to respond by contraction to internal and external stimuli. Normally, excitation and contraction of the heart occur under the influence of impulses from the sinus node.

Impulses can be not only nomotopic (from the sinus node), but also heterotopic (from other parts of the conduction system of the heart). If the heart muscle is in a state of excitation, it does not respond to other impulses (absolute or relative refractory phase). Therefore, the heart muscle cannot be in a state of tetanic contraction. When the myocardium is excited, an electromotive force appears in it in the form of vector quantities, which is recorded in the form of an electrocardiogram.

Conductivity. Having originated in the sinus node, the impulse spreads orthograde through the atrial myocardium, then through the atrioventricular node, the His bundle, and the ventricular conduction system. The intraventricular conduction system includes the right branch of the His bundle, the main trunk of the left branch of the His bundle and its two branches, anterior and posterior, and ends with the Purkinje fibers, which transmit impulses to the cells of the contractile myocardium (Fig. 2).

The speed of propagation of the excitation wave in the atria is 1 m/sec, in the conducting system of the ventricles 4 m/sec, atrioventricular node 0.15 m/sec. The retrograde conduction of the impulse is sharply slowed down, the atrioventricular delay makes it possible for the atria to contract before the ventricles. The most vulnerable parts of the conduction system are: atrioventricular node with AV delay, right bundle branch of His, left anterior branch,

As a result of the impulse, the process of excitation (depolarization) of the myocardium begins at the beginning of the interventricular septum, the right and left ventricles. Excitation of the right ventricle may begin earlier (0.02"") than the left. Subsequently, depolarization captures the myocardium of both ventricles, and the electromotive force (total vector) of the left ventricle is greater than the right one.

th. The process of depolarization proceeds from the apex to the base of the heart, from the endocardium to the epicardium.

The process of recovery (repolarization) of the myocardium begins at the epicardium and spreads to the endocardium. During repolarization, a significantly lower electromotive force (EMF) occurs than during depolarization.

The process of depolarization and repolarization of the myocardium is accompanied by bioelectric phenomena. It is known that the protein-lipid membrane of the cell has the properties of a semi-permeable membrane. K+ ions easily penetrate through the membrane and phosphates, sulfates, and proteins do not penetrate. Since these ions are negatively charged,

they attract positively charged K+ ions. The concentration of K+ ions inside the cell is 30 times higher than in the extracellular fluid. Nevertheless, negative charges predominate on the inner surface of the membrane. Na+ ions are located predominantly on outer surface membranes, because the cell membrane at rest is poorly permeable to Na+. The Na+ concentration in the extracellular fluid is 20 times higher than inside the cell. The cell potential at rest is approximately

but 70–90 mV.

When the myocardium is depolarized, the permeability of cell membranes changes, sodium ions easily penetrate the cell and change the charge of the inner surface of the membrane. Due to the fact that Na+ enters the cell, the electrical charge on the outer surface of the membrane changes. Depolarization changes the charge on the outer and inner surfaces of cell membranes. The potential difference that occurs during excitation is called the action potential, it is about 120 mV. During the process of repolarization, K+ ions leave the cell and restore the resting potential. Upon completion of repolarization, Na+ is removed from the cell into the extracellular space using sodium pumps, and K+ ions actively penetrate into the cell through the semi-permeable cell membrane (Fig. 3).

The repolarization process proceeds more slowly than depolarization and causes less emf than the excitation process.

Repolarization begins in the subepicardial layers and ends in the subendocardial layers.

The process of depolarization in a muscle fiber is more complex than in an individual cell. The excited area is charged negatively in relation to the area at rest, and dipole charges are formed, equal in magnitude and opposite in direction. If a dipole with a positive charge moves towards the electrode, a positively directed tooth is formed, if from the electric

troda – negatively directed.

The human heart contains many muscle fibers. Each excited fiber represents a dipole. Dipoles move in different directions. The sum of the muscle fiber vectors of the right and left ventricles is written as a scalar value

– electrocardiograms.

IN In each lead, the ECG curve represents the sum of the vectors of the right and left ventricles and atria (biocardiogram theory).

3. NORMAL ECG IN STANDARD LEADS

IN At the beginning of the 20th century, Einthoven proposed standard leads. Einthoven presented the human body in the form of an equilateral triangle. The first standard lead registers the difference in potentials of the right and left hands, the second – the difference in potentials of the right hand and left leg, the third – the difference in potentials of the left hand and left leg. According to Kirchhoff's law, the second lead represents the algebraic sum of the first and third leads. All elements of the electrocardiogram obey this rule. The first lead reflects the potentials of the subepicardial surface of the left ventricle, the third – the potentials of the posterior wall of the left ventricle and the subepicardial surface of the right ventricle.

A normal ECG in standard leads is represented by a series of waves and intervals, designated by Latin letters (Fig. 4). If the amplitude of the tooth is more than 5 mm, it is indicated by a capital letter, if less than 5 mm, then by a small letter.

Wave P - this atrial complex consists of a hollow ascending limb and a symmetrically located descending limb, which are connected by a rounded apex. The duration (width) of the tooth does not exceed 0.08-0.1 seconds (1 mm - 0.02 ""), the height P is 0.5-2.5 mm. The largest amplitude P in

second standard lead. Normal PII>PI>PIII. PI>0,l"" indicates hypertrophy of the left atrium, with PIII>2.5 mm we can talk about hypertrophy of the right atrium. The duration of the P wave is measured from the beginning of the ascending to the end of the descending knee, the amplitude

P - from the base of the tooth to its top.

Interval PQ (R) - from the beginning of P to the beginning of g or R. It corresponds to the time of passage of the impulse through the atria, through the atrioventricular node, along the bundle of His, the legs of the bundle of His, Purkinje fibers.

The duration of the PQ interval normally fluctuates 0.12""÷ 0.20"" and depends on the pulse rate. Prolongation of the PQ interval is observed when atrioventricular conduction is impaired; shortening of PQ is associated with a sympatheticoadrenal reaction, premature ventricular excitation syndrome, atrial or nodal pacemaker, etc.

Segment PQ – located from the end of P to the beginning of Q (R). The ratio of P to the PQ segment is called the Makruz index, its norm is 1.1–1.6. An increase in the Macruse index indicates hypertrophy of the left atrium.

The QRS complex reflects the process of ventricular depolarization, measured in the second standard lead from the beginning of Q to the end of S, the normal duration is 0.05–0.1 "". QRS prolongation is associated with myocardial hypertrophy or intraventricular conduction disturbances.

The Q wave is associated with the excitation of the interventricular septum (optional, with a negative amplitude). The duration of Q in the first and second standard leads is up to 0.03"", in the third standard lead - up to 0.04". The amplitude of Q is normally no more than 2 mm or no more than 25% R. Widening of Q and its increase indicate the presence of focal changes in the myocardium.

The R wave is caused by ventricular depolarization, has an ascending limb, an apex, and a descending limb. The time from Q (R) to the perpendicular from the apex of R indicates an increase in the rate of depolarization of the ventricles and is called the time of internal deviation, for the left ventricle no more than 0.04"", for the right - 0.035"". Jagged R

Back in the 19th century, scientists, studying the anatomical and physiological characteristics of the heart of animals and humans, came to the conclusion that this organ is a muscle capable of generating and conducting electrical impulses. The human heart consists of two atria and two ventricles. Correct conduction of electrical signals through them ensures good contractility of the myocardium (heart muscle) and ensures the correct rhythm of contractions.

Initially, the impulse occurs in the cells of the sinoatrial (atrial) node, located on the border of the right atrium and the superior vena cava. It then spreads through the atria, reaching the atrioventricular node (located between the right atrium and the ventricle), here there is a slight delay in the impulse, then passes through the His bundle in the thickness of the interventricular septum and spreads along the Purkinje fibers in the walls of both ventricles. It is this path of conducting an electrical signal through the conduction system of the heart that is correct and ensures full cardiac contraction, since under the influence of the impulse the muscle cell contracts.

conduction system of the heart

A little later, scientists were able to create a device that allows them to record and read the processes of electrical activity in the heart by placing electrodes on the chest. A huge role here belongs to Willem Uythoven, a Dutch scientist who designed the first apparatus for electrocardiography and proved that in people with various heart diseases, the indicators of cardiac electrophysiology change during the recording of an ECG (1903). So, what is electrocardiography?

is an instrumental method for studying the electrophysiological activity of the heart, based on recording and graphically depicting the potential difference that occurs during the contraction of the heart muscle for the purpose of diagnosing heart diseases.

An ECG is performed by placing electrodes on the anterior wall of the chest in the projection of the heart and limbs, then using the ECG device itself, the electrical potentials of the heart are recorded and displayed as a graphic curve on a computer monitor or thermal paper (using an ink recorder). Electrical impulses generated by the heart propagate throughout the body, so for ease of reading, leads were developed - circuits that make it possible to record potential differences in different parts of the heart. There are three standard leads - 1, 11, 111; three enhanced leads – aVL, aVR, aVF; and six chest leads - from V1 to V6. All twelve leads are displayed on the ECG film and allow you to see the work of a particular part of the heart in each specific lead.

In modern times, the electrocardiography method is very widespread due to its availability, ease of use, low cost and lack of invasiveness (violation of the integrity of body tissues). ECG allows timely diagnosis of many diseases - acute coronary pathology(myocardial infarction), hypertension, rhythm and conduction disorders, etc., and also allows you to evaluate the effectiveness of the medication or surgical treatment heart diseases.

The following ECG methods are distinguished:

- Holter (24-hour) ECG monitoring– the patient is fitted with a portable small device on the chest, which records the slightest deviations in the activity of the heart during the day. The good thing about this method is that it allows you to monitor the work of the heart during the patient’s normal everyday activities and for a longer period of time than when taking a simple ECG. Helps in recording cardiac arrhythmias and myocardial ischemia that were not detected with a single ECG.
- ECG with stress– medication (with the use of pharmacological drugs) or physical activity (treadmill test, bicycle ergometry) is used; as well as electrical stimulation of the heart when a sensor is inserted through the esophagus (TEPS - transesophageal electrophysiological study). Allows you to diagnose initial stages IHD, when the patient complains of heart pain during physical activity, and the ECG at rest does not reveal any changes.
- transesophageal ECG– as a rule, it is performed before TEE, as well as in cases where an ECG through the anterior chest wall turns out to be uninformative and does not help the doctor establish the true nature of heart rhythm disturbances.

Indications for ECG

Why is an ECG necessary? Electrocardiography allows you to diagnose many cardiac diseases. Indications for ECG are:

1. Routine examination of children, adolescents, pregnant women, military personnel, drivers, athletes, people over 40 years of age, patients before surgery, patients with other diseases (diabetes mellitus, diseases thyroid gland, lung diseases, diseases digestive system and etc);

2. Diagnosis of diseases:
- arterial hypertension;
- coronary heart disease (CHD), including acute, subacute myocardial infarction, post-infarction cardiosclerosis;
- endocrine, dysmetabolic, alcohol-toxic cardiomyopathies;
- chronic heart failure;
- heart defects;
- rhythm and conduction disorders - SVC syndrome, atrial fibrillation, extrasystole, tachycardia - and bradycardia, sinoatrial and atrioventricular blockade, bundle branch block, etc.
- pericarditis

3. Control after treatment of the listed diseases (drug or cardiac surgery)

Contraindications for ECG

There are no contraindications for standard electrocardiography. However, the procedure itself can be difficult in persons with complex chest injuries, with a high degree of obesity, with severe chest hair (the electrodes simply will not be able to fit tightly to the skin). The presence of a pacemaker in the patient’s heart can also significantly distort ECG data.

There are contraindications for performing an ECG with stress: acute period of myocardial infarction, acute infectious diseases, deterioration of the course arterial hypertension, coronary disease heart disease, chronic heart failure, complex rhythm disturbances, suspicion of dissection of an aortic aneurysm, decompensation (worsening of the course) of diseases of other organs and systems - digestive, respiratory, urinary. Contraindications for transesophageal ECG are diseases of the esophagus - tumors, strictures, diverticula, etc.

Preparing for the study

An ECG does not require special preparation for the patient. There are no restrictions on normal household activities, eating or drinking. It is not recommended to consume coffee, alcohol or large amounts of cigarettes before the procedure, as this will affect the functioning of the heart at the time of the study, and the results may be misinterpreted.

How is electrocardiography performed?

An ECG can be performed in a hospital or clinic. In the hospital, a study is carried out on patients delivered by ambulance medical care with cardiac symptoms, or patients already hospitalized in a hospital of any profile (therapeutic, surgical, neurological, etc.). In the clinic, an ECG is performed as a routine examination, as well as for patients whose health condition does not require urgent hospitalization.

Carrying out an ECG

The patient comes at the appointed time to the ECG diagnostic room, lies down on the couch on his back; the nurse wipes the chest, wrists and ankles with a sponge moistened with water (for better conductivity) and places electrodes - one “clothespin” on the wrists and feet and six “suction cups” on the chest in the projection of the heart. Next, the device is turned on, the electrical activity of the heart is read, and the result is recorded in the form of a graphic curve on thermal film using an ink recorder or immediately saved in the doctor’s computer. The entire study lasts about 5 - 10 minutes, without causing any discomfort in the patient.

Next, the ECG is analyzed by a doctor functional diagnostics, after which the conclusion is given to the patient or transferred directly to the attending physician’s office. If the ECG does not reveal any serious changes requiring further observation in the hospital, the patient can go home.

ECG interpretation

Now let's take a closer look at the analysis of the electrocardiogram. Each complex normal electrocardiogram consists of teeth P, Q, R, S, T and segments – PQ and ST. The teeth can be positive (directed upward) or negative (directed downward), and the segments are above and below the isoline.

The patient will see the following indicators in the ECG protocol:

1. Source of excitation. During normal heart function, the source is located in the sinus node, that is, the rhythm is sinus. Its signs are the presence of positive P waves in the 11th lead in front of each ventricular complex of the same shape. Non-sinus rhythm is characterized by negative P waves and appears with sinoatrial block, extrasystole, atrial fibrillation, atrial flutter, ventricular fibrillation and flutter.

2. Correctness (regularity) of the rhythm. It is determined when the distance between the R waves of several complexes differs by no more than 10%. If the rhythm is abnormal, the presence of arrhythmias is also indicated. A sinus but irregular rhythm occurs with sinus (respiratory) arrhythmia, and a sinus regular rhythm occurs with sinus brady and tachycardia.

3. HR - heart rate. Normally 60 – 80 beats per minute. A condition with a heart rate below this value is called bradycardia (slow heartbeat), and above it is called tachycardia (rapid heartbeat).

4. Determination of EOS (rotation of the electrical axis of the heart). EOS is the summing vector of the electrical activity of the heart, coinciding with the direction of its anatomical axis. Normally, the EOS varies from semi-vertical to semi-horizontal position. In obese people, the heart is located horizontally, while in thin people it is more vertical. EOS deviations may indicate myocardial hypertrophy (proliferation of the heart muscle, for example, with arterial hypertension, heart defects, cardiomyopathies) or conduction disorders (blockade of the legs and branches of the His bundle).

5. Analysis of the P wave. The P wave reflects the occurrence of an impulse in the sinoatrial node and its conduction through the atria. Normally, the P wave is positive (the exception is lead aVR), its width is up to 0.1 sec, and its height is from 1.5 to 2.5 mm. Deformation of the P wave is characteristic of pathology mitral valve(P mitrale) or diseases of the bronchopulmonary system with the development of circulatory failure (P pulmonale).

6. PQ segment analysis. Reflects the conduction and physiological delay of the impulse through the atrioventricular node and is 0.02 - 0.09 sec. A change in duration is characteristic of conduction disorders - shortened PQ syndrome, atrioventricular block.

7. Analysis of the QRS complex. Reflects the conduction of an impulse along the interventricular septum and ventricular myocardium. Normally, its duration is up to 0.1 seconds. A change in its duration, as well as deformation of the complex, is characteristic of myocardial infarction, bundle branch block, ventricular extrasystole, and paroxysmal ventricular tachycardia.

8. ST segment analysis. Reflects the process of complete coverage of the ventricles by excitation. Normally it is located on the isoline; a shift up or down by 0.5 mm is allowed. Depression (decrease) or elevation of ST indicates the presence of myocardial ischemia or the development of myocardial infarction.

9. Analysis of the T wave. Reflects the process of attenuation of ventricular excitation. Normally positive. A negative T also indicates the presence of ischemia or small focal myocardial infarction.

The patient must remember that independent analysis of the ECG protocol is not acceptable. Interpretation of electrocardiogram indicators should only be carried out by a functional diagnostics doctor, cardiologist, therapist or emergency physician, since only a doctor, during an in-person examination, can compare the data obtained with clinical symptoms and the risk of conditions requiring treatment, including in a hospital. Otherwise, underestimating the ECG conclusion can harm a person’s health and life.

ECG complications

Are there possible complications during electrocardiography? The ECG procedure is quite harmless and safe, so there are no complications. When performing an ECG with stress, an increase in blood pressure, rhythm and conduction disturbances in the heart may occur, but this, rather, can be attributed not to complications, but to diseases, for the clarification of which provocative tests were prescribed.

General practitioner Sazykina O.Yu.

ECG is the most common method for diagnosing the heart organ. Using this technique, you can obtain sufficient information about various pathologies in the heart, as well as carry out monitoring during therapy.

What is electrocardiography?

Electrocardiography is a method for studying the physiological state of the heart muscle, as well as its performance.

For the study, a device is used that registers all changes in the physiological processes in the organ and, after processing the information, displays it in a graphical image.

The graph shows:

• Conduction of electrical impulses by the myocardium;
• Heart muscle contraction frequency (HR - );
• Hypertrophic pathologies of the cardiac organ;
• Scars on the myocardium;
• Changes in myocardial functionality.

All these changes in the physiology of the organ, and in its functionality, can be recognized on the ECG. Cardiograph electrodes record bioelectric potentials that appear during contraction of the heart muscle.

Electrical impulses are recorded in different parts of the heart organ, so there is a potential difference between the excited areas and the non-excited areas.

It is this data that is captured by the device’s electrodes, which are attached to different parts of the body.

Who is prescribed an ECG study?

This technique is used for the diagnostic study of certain cardiac disorders and abnormalities.

Indications for the use of ECG:

What is the verification for?

Using this method of checking the heart, it is possible to determine abnormalities in cardiac activity at an early stage of the development of pathology.

An electrocardiogram can detect the most minor changes occurring in an organ that exhibits electrical activity:

• Thickening and expansion of the walls of the chambers;
• Deviations from the standard size of the heart:
• The focus of necrosis in myocardial infarction;
• The size of ischemic myocardial damage and many other deviations.

It is recommended to conduct a diagnostic study of the heart after the age of 45, since during this period the human body undergoes changes at the hormonal level, which affects the functioning of many organs, including the functioning of the heart.

It is enough to undergo an ECG for preventive purposes once a year.

Types of diagnostics

There are several methods diagnostic study ekg:

• Resting technique. This is a standard technique that is used in any clinic. If the ECG readings at rest do not give a reliable result, then it is necessary to use other methods of ECG examination;
• Load verification method. This method includes a load on the body (an exercise bike, a treadmill test). In this method, a sensor for measuring cardiac stimulation during exercise is inserted through the esophagus. This type of ECG is capable of identifying pathologies in the heart organ that cannot be recognized in a person at rest. Also, the cardiogram is done at rest after the load;
• Monitoring within 24 hours (Holter study). According to this method, a sensor is installed in the patient’s chest area, which records the functioning of the heart organ for 24 hours. With this method of research, a person is not freed from his daily household responsibilities, and this is a positive fact in this monitoring;
• ECG through the esophagus. This testing is performed when it is not possible to obtain the necessary information through the chest.

If the symptoms of these diseases are pronounced, you should visit a therapist or cardiologist and undergo an ECG.

• Pain in the chest around the heart;
• High arterial pressure- hypertonic disease;
• Heart pain due to temperature changes in the body;
• Age over 40 calendar years;
• Inflammation of the pericardium - pericarditis;
• Rapid heartbeat - tachycardia;
• Irregular contraction of the heart muscle - arrhythmia;
• Inflammation of the endocardium - endocarditis;
• Pneumonia - pneumonia;
• Bronchitis;
• Bronchial asthma;
• Angina pectoris - coronary heart disease;
• Atherosclerosis, cardiosclerosis.

And also with the development of such symptoms in the body:

• Dyspnea;
• Dizziness;
• Headache;
• Fainting;
• Heartbeat.

Contraindications for using ECG

There are no contraindications for performing an ECG.

There are contraindications for stress testing (stress ECG method):

• Cardiac ischemia;
• Exacerbation of existing cardiac pathologies;
• Acute myocardial infarction;
• Arrhythmia in severe stage;
• Severe form of hypertension;
• Infectious diseases in acute form;
• Severe heart failure.

If an ECG is needed through the esophagus, then a disease of the digestive system is a contraindication.

An electrocardiogram is safe and can be performed this analysis pregnant. ECG does not affect the intrauterine formation of the fetus.

Preparing for the study

This test does not require any necessary preparation before studying.

But there are some rules for this:

• You can eat before the procedure;
• You can take water without limiting your quantity;
• Do not take drinks containing caffeine before the cardiogram;
• Stop taking it before the procedure alcoholic drinks;
• Do not smoke before the ECG.

Execution technique

An electrocardiogram is performed in every clinic. If there is an emergency hospitalization, then an ECG can be done within the walls of the emergency room, and an ECG can also be brought by an emergency doctor upon arrival to the call.

Technique for performing a standard ECG at a doctor’s appointment:

• The patient needs to lie in a horizontal position;
• The girl needs to take off her bra;
• Areas of the skin on the chest, hands and ankles are wiped with a damp cloth (for better conduction of electrical impulses);
• Electrodes are attached to clothespins on the ankles of the legs and on the hands, and 6 electrodes with suction cups are placed on the chest;
• After this, the cardiograph is turned on and the recording of the functioning of the cardiac organ on thermal film begins. The cardiogram graph is written in the form of a curve;
• The procedure takes no more than 10 minutes. The patient does not feel discomfort; there are no unpleasant feelings during the ECG;
• The cardiogram is deciphered by the doctor who performed the procedure and the decoding is transferred to the patient’s attending doctor, which allows the doctor to find out about pathologies in the organ.

Correct application of electrodes by color is necessary:

• On the right wrist - a red electrode;
• On the left wrist there is a yellow electrode;
• Right ankle - black electrode;
• The left ankle is a green electrode.

Correct placement of electrodes

Reading results

After the result of studying the cardiac organ is obtained, it is deciphered.

The result of an electrocardiographic study includes several components:

• Segments - ST, as well as QRST and TP- this is the distance that is marked between the teeth located nearby;
• Teeth - R, QS, T, P- these are the angles that have acute form, and also have a downward direction;
• PQ interval is a gap that includes teeth and segments. The intervals include the time period of passage of the impulse from the ventricles to the atrium chamber.

The waves on the electrocardiogram recording are designated by the letters: P, Q, R, S, T, U.

Each letter of the teeth is a position in the parts of the heart organ:

• R— depolarity of the atria of the myocardium;
• QRS- ventricular depolarity;
• T- ventricular repolarization;
• U wave, which is mild, indicates the process of repolarization of areas of the ventricular conduction system.

The paths along which the discharges move are indicated on the 12-lead cardiogram. When deciphering, you need to know which leads are responsible for what.

Standard leads:

• 1 - first lead;
• 2 - second:
• 3 - third;
• AVL is analogous to lead No. 1;
• AVF is analogous to lead No. 3;
• AVR - display in mirror format of all three leads.

Thoracic leads (these are points that are located on the left side of the sternum in the area of ​​the heart organ):

• V No. 1;
• V No. 2;
• V No. 3;
• V No. 4;
• V No. 5;
• V No. 6.

The value of each lead records the course of an electrical impulse through a specific location in the cardiac organ.

Thanks to each lead, the following information can be recorded:

• The cardiac axis is designated - this is when the electrical axis of the organ is combined with the anatomical cardiac axis (clear boundaries of the location of the heart in the sternum are indicated);
• The structure of the walls of the atrium and ventricular chambers, as well as their thickness;
• The nature and strength of blood flow in the myocardium;
• The sinus rhythm is determined and whether there are any interruptions in the sinus node;
• Is there any deviation in the parameters of the passage of impulses along the wire paths of the organ.

Based on the results of the analysis, the cardiologist can see the strength of excitation of the myocardium and determine the time period during which systole passes.

Photo Gallery: Segment and Scar Measurements

Heart organ norms

All main values ​​are included in this table and mean normal indicators healthy person. If minor deviations from the norm occur, then this does not indicate pathology. The reasons for small changes in the heart do not always depend on the functionality of the organ.

index of cardiac teeth and segments	normative level in adults	norm children
HR (frequency of contraction of the heart muscle)	60 beats per minute to 80 beats	110.0 strokes/minute (up to 3 calendar years);
		100.0 beats/minute (up to 5th birthday);
		90.0 -100.0 beats / minute (up to 8 calendar years);
		70.0 - 85.0 beats / minute (up to 12 years of age).
T	0.120 - 0.280 s	-
QRS	0.060 - 0.10 s	0.060 - 0.10 s
Q	0.030 s	-
PQ	0.120 s - 0.2 s	0.20 s
R	0.070 s - 0.110 s	no more than 0.10 s
QT	-	no more than 0.40 s

How to decipher a cardiogram yourself

Everyone wants to decipher a cardiogram before even reaching the attending doctor’s office.

The main task of the organ is performed by the ventricles. The chambers of the heart have partitions between them that are relatively thin.

The left side of the organ and its right side also differ from each other and have their own functional responsibilities.

The load on the right side of the heart and on its left side is also different.

The right ventricle performs the function of providing biological fluid - pulmonary blood flow, and this is a less energy-consuming load than the function of the left ventricle to push blood flow into the large blood flow system.

The left-sided ventricle is more developed than its right neighbor, but it also suffers much more often. But regardless of the degree of load, the left side of the organ and the right side must work harmoniously and rhythmically.

The structure of the heart does not have a uniform structure. It contains elements that are capable of contracting - this is the myocardium, and elements that are irreducible.

The irreducible elements of the heart include:

• Nerve fibers;
• Arteries;
• valves;
• Fatty fiber.

All these elements differ in the electrical conductivity of the impulse and the response to it.

Functionality of the heart organ

The cardiac organ has the following functional responsibilities:

• Automatism is an independent mechanism for releasing impulses that subsequently cause cardiac excitation;
• Myocardial excitability is the process of activation of the heart muscle under the influence of sinus impulses;
• Conduction of impulses through the myocardium - the ability to conduct impulses from the sinus node to the contractile function of the heart;
• The crushing of the myocardium under the influence of impulses - this function allows the chambers of the organ to relax;
• Myocardial tonicity is a condition during diastole when the heart muscle does not lose its shape and provides continuous cardiac cycle;
• in statistical polarization (diastole state) - electrically neutral. Under the influence of impulses, biocurrents are formed in it.

ECG analysis

A more accurate interpretation of electrocardiography is made by calculating the waves by area, using special leads - this is called vector theory. Quite often in practice, only the direction indicator of the electrical axis is used.

This indicator includes the QRS vector. When deciphering this analysis, the direction of the vector, both horizontal and vertical, is indicated.

The results are analyzed in a strict sequence, which helps to determine the norm, as well as deviations in the functioning of the cardiac organ:

• The first is an assessment of heart rhythm and heart rate;
• Intervals are being calculated (QT at a rate of 390.0 - 450.0 ms);
• The duration of systole qrst is calculated (using the Bazett formula);

If the interval becomes longer, then the doctor may make a diagnosis:

• Pathology atherosclerosis;
• Ischemia of the cardiac organ;
• Inflammation of the myocardium - myocarditis;
• Cardiac rheumatism.

If the result shows a shortened time interval, then pathology can be suspected - hypercalcemia.

If the conductivity of the pulses is calculated by a special computer program, then the result is more reliable.

• EOS position. The calculation is carried out from the isoline based on the height of the teeth of the cardiogram, where the R wave is higher than the S wave. If it is the other way around, and the axis is deviated to the right, then there is a violation in the performance of the right-sided ventricle. If the axis is deviated to the left side, and the height of the S wave is higher than the R wave in the second and third leads, then there is an increase in the electrical activity of the left ventricle, and a diagnosis of left ventricular hypertrophy is made;
• Next, the QRS complex of cardiac impulses is studied, which develop during the passage of electrical waves to the ventricular myocardium, and determines their functionality - according to the norm, the width of this complex is no more than 120 ms and the complete absence of a pathological Q wave. If this interval shifts, then there is a suspicion of blocking the bundle branches, as well as for disturbances in conductivity. Cardiological data on the right-sided bundle branch block are data on hypertrophy of the right-sided ventricle, and blockade of the left branch is on the hypertrophy of the left-sided ventricle;
• After studying the legs of His, a description of the study of ST segments occurs. This segment displays the recovery time of the myocardium after its depolarization, which is normally present on the isoline. The T wave is an indicator of the process of repolarization of the left and right ventricles. The T wave is asymmetrical and has an upward direction. Change of T wave longer than the QRS complex.

This is what the heart of a healthy person looks like in all respects. In pregnant women, the heart is located in a slightly different place in the chest, and therefore its electrical axis is also shifted.

Depending on the intrauterine development of the fetus, additional stress occurs on the heart muscle, and an electrocardiogram during the period of intrauterine development of the child reveals these signs.

Cardiogram indicators in childhood change as the child grows. ECGs in children also detect abnormalities in the cardiac organ and are interpreted in accordance with the standard scheme. After the age of 12, a child's heart corresponds to an adult's organ.

Is it possible to fool an ECG?

Many people try to fool electrocardiography. The most common place is the military registration and enlistment office.

In order for the cardiogram readings to be abnormal, many take medications that increase or decrease blood pressure, drink a lot of coffee, or take heart medications.

Accordingly, the diagram shows the state of increased heart rate in a person.

Many people do not understand that by trying to deceive the ECG machine, one can develop complications in the heart organ and in the vascular system. The rhythm of the heart muscle may be disrupted and ventricular repolarization syndrome may develop, and this is fraught with acquired heart disease and heart failure.

The following pathologies in the body are most often simulated:

• Tachycardia- increased contraction of the heart muscle. Occurs from high loads to ECG analysis, drinking large amounts of drinks containing caffeine, taking medications to increase blood pressure;
• Early ventricular repolarization (ERV)- this pathology is provoked by taking heart medications, as well as drinking drinks that contain caffeine (energy drinks);
• Arrhythmia- incorrect heart rhythm. This pathology can be caused by taking beta blockers. Limitless consumption of coffee drinks and large amounts of nicotine also disrupt the correct rhythm of the myocardium;
• Hypertension- also provoked by drinking too much coffee and overloading the body.

The danger in wanting to deceive an ECG is that it the easy way You can actually develop heart pathology, because taking heart medications by a healthy body causes additional stress on the heart organ and can lead to its failure.

Then it will be necessary to conduct a comprehensive instrumental examination to identify pathology in the cardiac organ and in the bloodstream system, and to determine how complicated the pathology has become.

ECG diagnosis: heart attack

One of the most serious cardiac diagnoses, which is detected by the ECG technique, is a bad cardiogram - a heart attack. In case of myocardial infarction, the decoding indicates the area of ​​myocardial damage by necrosis.

This is the main task of the ECG method for myocardium, because the cardiogram is the first instrumental study of pathology during a heart attack.

The ECG determines not only the location of myocardial necrosis, but also the depth to which the necrotic destruction has penetrated.

The ability of electrocardiography is that the device can distinguish the acute form of a heart attack from the pathology of an aneurysm, as well as from old infarction scars.

In the cardiogram, during myocardial infarction, an elevated ST segment is written, as well as the R wave reflects deformation, and provokes the appearance of a sharp T wave. The characteristics of this segment are similar to a cat’s back during a heart attack.

The ECG shows myocardial infarction with the Q wave type, or without this wave.

How to calculate your heart rate at home

There are several methods for counting the number of heart impulses in one minute:

• A standard ECG records at a rate of 50.0 mm per second. In this situation, the contraction frequency of the heart muscle is calculated using the formula - heart rate is equal to 60 divided by R-R (in millimeters) and multiplied by 0.02. There is a formula, with a cardiograph speed of 25 millimeters per second - heart rate is equal to 60 divided by R-R (in millimeters) and multiplied by 0.04;
• You can also calculate the frequency of heart impulses using a cardiogram using the following formulas: at a device speed of 50 millimeters per second, the heart rate is 600, divided by the average coefficient of the totality of cells (large) between the types of R waves on the graph. At a device speed of 25 millimeters per second, the heart rate is equal to the index 300, divided by the average index of the number of cells (large) between the type of R wave on the graph.

ECG of a healthy heart organ and with cardiac pathology

electrocardiography parameters	standard indicator	deciphering deviations and their characteristics
tooth distance R–R	the segments between all R teeth are the same in distance	different distance indicates:
		· about cardiac arrhythmia;
		· pathology of extrasystole;
		· weak sinus node;
		· blockade of cardiac conduction.
Heart rate	up to 90.0 beats per minute	· tachycardia - heart rate higher than 60 pulses per minute;
		· bradycardia - heart rate less than 60.0 beats per minute.
P wave (atrial contractility)	ascends in an arcing pattern, approximately 2 mm high, anterior to each R wave, and may also be absent from leads 3, V1, and AVL	· with thickening of the walls of the atria myocardium - a tooth up to 3 mm high and up to 5 mm wide. Consists of 2 halves (double-humped);
		· if the rhythm of the sinus node is disturbed (the node does not send an impulse) - complete absence in leads 1, 2, as well as FVF, from V2 to V6;
		· in atrial fibrillation - small waves that are present in the spaces of the R-type waves.
interval between teeth of types P–Q	line between teeth type P - Q horizontal 0.10 seconds - 0.20 seconds	· atrioventricular block of the heart muscle - in case of an increase in the interval by 10 millimeters at an electrocardiograph recording speed of 50 millimeters per second;
		· WPW syndrome - when the interval between these teeth is shortened by 3 millimeters.
QRS complex	the duration of the complex on the graph is 0.10 seconds (5.0 mm), after the complex there is a T wave, and there is also a straight line that is located horizontally	· blocking of the bundle branches - an enlarged ventricular complex means hypertrophy of the myocardial tissue of these ventricles;
		· paroxysmal type of tachycardia - if the complexes go up and have no gaps. This may also indicate the disease ventricular fibrillation;
		· infarction of the cardiac organ - a complex in the form of a flag.
type Q	the wave is directed downward with a depth of at least one-fourth of the R wave; also, this wave may not be present on the cardiogram	deep down and wide along the Q-type tooth standard types leads or chest leads are signs of a heart attack in the acute stage of the pathology.
R wave	a tall tooth, which is directed upward, 10.0 - 15.0 millimeters high with sharp ends. Present in all types of leads.	· hypertrophy of the left ventricle - different in height in different leads and more than 15.0 - 20.0 millimeters in leads No. 1, AVL, as well as V5 and V6;
		· blocking of the bundle branches - notching and bifurcation at the top of the R wave.
S tooth type	present in all types of leads, the tooth is directed downward, has a sharp end, its depth is from 2.0 to 5.0 millimeters in leads of the standard type.	· according to the standard in chest forms in leads, this wave appears to have a depth equal to the height of the R wave, but it should be higher than 20.0 millimeters, and in leads V2 and V4, the depth of the S wave is equal to the height of the R wave. Low depth or jagged S in leads 3, AVF , V1, and V2 are hypertrophy of the left ventricle.
cardiac segment S–T	in accordance with a straight line that lies horizontally between the types of teeth S - T	· ischemia of the cardiac organ, heart attack and angina pectoris are marked by a segment line up or down by more than 2.0 millimeters.
T-prong	directed upward along an arc type with a height less than 50% of the height from the R wave, and in lead V1 it has an equal height to it, but not more than it.	· cardiac ischemia or overload of the cardiac organ - a high double-humped tooth with a sharp end in the chest leads, as well as standard ones;
		· myocardial infarction in the acute stage of the disease - this T wave is combined with an S–T type interval, as well as with an R wave, and a flag appears on the graph.

Description and characteristics of electrocardiography, which are normal or pathological, are given in a simplified version of the decrypted information.

A complete decoding, as well as a conclusion about the functionality of the cardiac organ, can only be given by a specialized doctor - a cardiologist who has a complete and expanded professional circuit for reading an electrocardiogram.

In case of disorders in children, a professional opinion and evaluation of the cardiogram is issued only by a pediatric cardiologist.

Video: Daily monitoring.

Conclusion

ECG readings are the basis for making an initial diagnosis during emergency hospitalization, as well as for establishing a final cardiac diagnosis, together with other instrumental diagnostic methods.

Importance ECG diagnostics was assessed back in the 20th century and to this day electrocardiography remains the most common research technique in cardiology. Using the ECG method, diagnostics is made not only of the heart organ, but also of the vascular system of the human body.

The advantage of electrocardiography is its simplicity of execution, low cost for diagnosis and accuracy of indications.

To use the results of an ECG to make an accurate diagnosis, it is necessary only by comparing its results with the results of other diagnostic studies.

ECG interpretation of an electrocardiogram is considered a complex process that only a diagnostician or cardiologist can do. They carry out decoding, identifying various defects and disruptions in the functioning of the human heart muscle. This diagnostic method is widely used today in all medical institutions. The procedure can be done either in a clinic or in an ambulance.

Electrocardiography is a science that studies the rules of the procedure, ways to interpret the results obtained, and explains unclear points and situations. With the development of the Internet, you can even decipher an ECG yourself, using special knowledge.

The electrocardiogram is deciphered by a special diagnostician who uses an established procedure that determines normal indicators and their deviations.

Heart rate and heart rate are assessed. In a normal state, the rhythm should be sinus, and the frequency should be from 60 to 80 beats per minute.

Intervals are calculated that characterize the duration of the moment of contraction. Special formulas are used here.

The normal QT interval is 390 - 450 ms. If the interval is violated, if it lengthens, the diagnostician may suspect atherosclerosis, rheumatism or myocarditis, as well as coronary heart disease in the patient. Also, the interval may shorten, and this indicates the presence of hypercalcemia. These parameters are calculated using a specialized automatic program that provides reliable results.

The location of the EOS is calculated from the isoline along the height of the teeth. If the indicators are significantly higher than each other, an axis deviation is noticed, defects in the functioning of the right or left ventricle are suspected.

An indicator showing the activity of the ventricles, the QRS complex, is formed during the passage of electrical impulses to the heart. It is considered normal when there is no defective Q wave and the distance does not exceed 120 ms. When this interval shifts, it is customary to talk about a conduction defect, or it is also called bundle branch block. In case of incomplete blockade, RV or LV hypertrophy can be suspected depending on the location of the line on the ECG. The transcript describes ST particles, which reflect the time of restoration of the initial position of the muscle relative to its complete depolarization. Under normal conditions, the segments should fall on the isoline, and the T wave, which characterizes the work of both ventricles, should be asymmetrical and directed upward. It should be longer than the QRS complex.

Only doctors specially involved in this can correctly decipher ECG indicators, but often an ambulance paramedic with extensive experience can easily recognize common heart defects. And this is extremely important in emergency situations.

When describing and decoding diagnostic procedure describe various characteristics of the work of the heart muscle, which are indicated by numbers and Latin letters:

• PQ is an indicator of atrioventricular conduction time. In a healthy person it is 0.12 - 0.2 s.
• P - description of the work of the atria. It may well indicate atrial hypertrophy. In a healthy person, the norm is 0.1 s.
• QRS - ventricular complex. In normal condition, the indicators are 0.06 - 0.1 s.
• QT is an indicator that can indicate cardiac ischemia, oxygen starvation, heart attack and rhythm disorders. Normal indicator should be no more than 0.45 s.
• RR - the gap between the upper points of the ventricles. Shows the constancy of heart contractions and allows you to count their frequency.

Cardiogram of the heart: interpretation and main diagnosed diseases

Decoding a cardiogram is a long process that depends on many indicators. Before deciphering the cardiogram, it is necessary to understand all the deviations in the functioning of the heart muscle.

Atrial fibrillation is characterized by irregular contractions of the muscle, which can be completely different. This violation is dictated by the fact that the clock is set not by the sinus node, as it should happen in a healthy person, but by other cells. The heart rate in this case ranges from 350 to 700. In this condition, the ventricles are not fully filled with incoming blood, which causes oxygen starvation, which affects all organs in the human body.

An analogue of this condition is atrial fibrillation. The pulse in this state will be either below normal (less than 60 beats per minute), or close to normal (60 to 90 beats per minute), or above the specified norm.

On the electrocardiogram, you can see frequent and constant contractions of the atria and, less often, the ventricles (usually 200 per minute). This is atrial flutter, which often occurs already in the acute phase. But at the same time, the patient tolerates it more easily than flickering. Blood circulation defects in this case are less pronounced. Trembling can develop as a result of surgical interventions, with various diseases, such as heart failure or cardiomyopathy. When a person is examined, fluttering can be detected due to rapid rhythmic heartbeats and pulse, swollen veins in the neck, increased sweating, general impotence and shortness of breath.

Conduction disorder - this type of heart disorder is called blockade. The occurrence is often associated with functional disorders, but can also be the result of various types of intoxication (due to alcohol or taking medications), as well as various diseases.

There are several types of disorders that a heart cardiogram shows. Deciphering these violations is possible based on the results of the procedure.

Sinoatrial - with this type of blockade, there is difficulty in the exit of the impulse from the sinus node. As a result, there is a syndrome of weakness of the sinus node, a decrease in the number of contractions, defects in the circulatory system, and as a result, shortness of breath and general weakness of the body.

Atrioventricular (AV block) - characterized by a delay in excitation in the atrioventricular node longer than the set time (0.09 seconds). There are several degrees of this type of blocking.

The number of contractions depends on the degree, which means the blood flow defect is more difficult:

• I degree - any compression of the atria is accompanied by an adequate amount of compression of the ventricles;
• II degree - a certain amount of compression of the atria remains without compression of the ventricles;
• III degree (absolute transverse block) - the atria and ventricles are compressed independently of each other, which is clearly shown by deciphering the cardiogram.

Conduction defect through the ventricles. The electromagnetic impulse from the ventricles to the muscles of the heart spreads through the trunks of the His bundle, its legs and branches of the legs. A blockage can occur at every level, and this will immediately affect the electrocardiogram of the heart. In this situation, it is observed that the excitation of one of the ventricles is delayed, because the electrical impulse goes around the blockage. Doctors divide blockages into complete and incomplete, as well as permanent or non-permanent blockages.

Myocardial hypertrophy is clearly shown by a cardiac cardiogram. Interpretation on the electrocardiogram - this condition shows the thickening of individual areas of the heart muscle and stretching of the chambers of the heart. This happens with regular chronic overload of the body.

• Syndrome of early ventricular repolarization. Often, this is the norm for professional athletes and people with congenitally large body weight. Clinical picture does not give and often goes away without any changes, so the interpretation of the ECG becomes more complicated.
• Various diffuse disorders in the myocardium. They indicate a myocardial nutritional disorder, as a result of dystrophy, inflammation or cardiosclerosis. The disorders are quite susceptible to treatment, and are often associated with a disorder of the body’s water-electrolyte balance, taking medical supplies, heavy physical activity.
• Non-individual changes in ST. A clear symptom of a disorder in myocardial supply, without severe oxygen starvation. Occurs during hormone imbalance and electrolyte imbalance.
• Distortion along the T wave, ST depression, low T. The cat's back on the ECG shows the state of ischemia (oxygen starvation of the myocardium).

In addition to the disorder itself, their position in the heart muscle is also described. The main feature of such disorders is their reversibility. Indicators, as a rule, are given for comparison with old studies in order to understand the patient’s condition, since it is almost impossible to read the ECG yourself in this case. If a heart attack is suspected, additional studies are performed.

There are three criteria by which a heart attack is characterized:

• Stage: acute, acute, subacute and cicatricial. Duration from 3 days to lifelong condition.
• Volume: large-focal and small-focal.
• Location.

Whatever the heart attack, this is always a reason to place a person under strict medical supervision, without any delay.

ECG results and heart rate description options

ECG results provide an opportunity to look at the state of a person’s heart. Exist different ways rhythm decoding.

sinus- This is the most common signature on the electrocardiogram. If no other indicators are indicated besides heart rate, this is the most successful forecast, which means the heart is working well. This type of rhythm suggests a healthy state of the sinus node, as well as the conduction system. The presence of other records proves existing defects and deviations from the norm. There is also atrial, ventricular or atrioventricular rhythm, which show which cells of specific parts of the heart set the rhythm.

Sinus arrhythmia- often normal in young adults and children. This rhythm is characterized by exit from the sinus node. However, the intervals between heart compressions are different. This is often associated with physiological disorders. Sinus arrhythmia should be carefully monitored by a cardiologist to avoid the development of serious diseases. This is especially true for persons with a predisposition to heart disease, as well as if the arrhythmia is caused by infectious diseases and heart defects.

Sinus bradycardia- characterized by rhythmic compression of the heart muscle with a frequency of about 50 beats. In a healthy person, this condition can often be observed in a state of sleep. This rhythm can manifest itself in people who are professionally involved in sports. Their ECG waves are different from those of an ordinary person.

Persistent bradycardia can characterize weakness of the sinus node, manifested in such cases by more rare contractions at any time of the day and under any condition. If a person experiences pauses during contractions, then surgery is prescribed to install a stimulator.

Extarsystole. This is a rhythm defect, which is characterized by extraordinary compressions outside the sinus node, after which the ECG results show a pause of increased length, called compensatory. The patient feels the heartbeat as uneven, chaotic, too fast or too slow. Sometimes patients are bothered by pauses in heart rhythm. Often there is a feeling of tingling or unpleasant tremors behind the breastbone, as well as a feeling of fear and emptiness in the stomach. Often such conditions do not lead to complications and do not pose a threat to humans.

Sinus tachycardia- with this disorder, the frequency exceeds the normal 90 beats. There is a division into physiological and pathological. Physiological is understood as the onset of such a state in a healthy person under certain physical or emotional stress.

May occur after drinking alcoholic beverages, coffee, or energy drinks. In this case, the condition is temporary and goes away quite quickly. The pathological appearance of this condition is characterized by periodic heartbeats that bother a person at rest.

The causes of the pathological appearance may be elevated temperature body, various infectious diseases, blood loss, long periods without water, anemia, etc. Doctors treat the underlying disease, and tachycardia is stopped only when the patient has a heart attack or acute coronary syndrome.

Paroxysmal tachycardia- in this condition, a person experiences a rapid heartbeat, expressed in an attack that lasts from several minutes to several days. The pulse may increase to 250 beats per minute. There are ventricular and supraventricular forms of such tachycardia. The main reason This condition is a defect in the passage of an electric pulse in a conducting system. This pathology is quite treatable.

You can stop an attack at home with the help of:

• Holding your breath.
• Forced cough.
• Dive into cold water faces.

WPW syndrome is a subtype of supraventricular tachycardia. The main provocateur of an attack is an additional nerve bundle, which is located between the atria and ventricles. To eliminate this defect, surgery or drug treatment is required.

CLC- extremely similar to the previous type of pathology. The presence of an additional nerve bundle here contributes to early excitation of the ventricles. The syndrome, as a rule, is congenital and manifests itself in a person with attacks of rapid rhythm, which is very clearly shown by ECG waves.

Atrial fibrillation May be episodic or permanent. A person feels pronounced atrial flutter.

ECG of a healthy person and signs of changes

The ECG of a healthy person includes many indicators by which a person’s health is judged. The ECG of the heart plays a very important role in the process of identifying abnormalities in the functioning of the heart, the most terrible of which is considered to be myocardial infarction. Necrotic zones of infarction can be diagnosed exclusively using electrocardiogram data. Electrocardiography also determines the depth of damage to the heart muscle.

ECG norms of a healthy person: men and women

ECG standards for children

The ECG of the heart is of great importance in the diagnosis of pathologies. The most dangerous heart disease is myocardial infarction. Only an electrocardiogram will be able to recognize the necrotic areas of the infarction.

Signs of myocardial infarction on an ECG include:

• the necrosis zone is accompanied by changes Q-R-S complex, resulting in a deep Q wave;
• the damage zone is characterized by a displacement (elevation) of the S-T segment, smoothing the R wave;
• the ischemic zone changes the amplitude and makes the T wave negative.

Electrocardiography also determines the depth of damage to the heart muscle.

How to decipher a heart cardiogram yourself

Not everyone knows how to decipher a heart cardiogram on their own. However, with a good understanding of the indicators, you can independently decipher the ECG and detect changes in the normal functioning of the heart.

First of all, it is worth determining the heart rate indicators. Normally, the heart rhythm should be sinus; the rest indicate the possible development of arrhythmia. Changes in sinus rhythm, or heart rate, suggest the development of tachycardia (faster rhythm) or bradycardia (slower rhythm).

Abnormal data of waves and intervals are also important, since you can read the cardiogram of the heart yourself using their indicators:

1. Prolongation of the QT interval indicates the development of coronary heart disease, rheumatic disease, and sclerotic disorders. A shortening of the interval indicates hypercalcemia.
2. An altered Q wave is a signal of myocardial dysfunction.
3. Sharpening and increased height of the R wave indicates right ventricular hypertrophy.
4. A split and widened P wave indicates left atrial hypertrophy.
5. An increase in the PQ interval and disruption of impulse conduction occurs with atrioventricular block.
6. The degree of deviation from the isoline in segment R-ST diagnoses myocardial ischemia.
7. Elevation of the ST segment above the isoline is a threat of acute infarction; a decrease in the segment registers ischemia.

The cardiac ruler consists of divisions (scales) defining:

• heart rate (HR);
• QT interval;
• millivolts;
• isoelectric lines;
• duration of intervals and segments.

This simple and easy-to-use device is useful for everyone to have for independently deciphering the ECG.