How and why is an ECG done? Heart lines. Why do you need an electrocardiogram?

Few people thought that preparation for an ECG even existed. This is not strange, because few doctors reported the necessary preliminary procedures. Usually the patient comes, lies down on the couch, a device is connected to him and a diagnosis is performed. And often the results of such a cardiogram are unpredictable. An ECG is needed to obtain information about the functioning of the heart. Already for a long time With this research method, doctors prevent possible complications in the functioning of this body. Carrying out electrocardiography is quite simple, but following basic rules contributes to the accurate outcome of the examination.

Preparatory stages

The attending physician must describe in detail to the patient everything necessary actions before taking an ECG. For men with abundant body hair, it is better to shave it off - this will allow for closer contact between the electrodes and the body. The day before the scheduled procedure, you need to take a warm shower. The same should be done the morning before. Clean skin is better suited for attaching electrodes. If the contact is close enough, the likelihood of interference will decrease dramatically. Be sure to carry out a water procedure after the session. This is due to the application of a special gel to the attachment points for better current conductivity. For people who are sensitive to cleanliness, it is better to bring a towel and a sheet. It's just worth remembering how many patients are on the couch in a day.

The main requirement for the human condition is calm. If before a cardiac examination a person has been subjected to intense physical activity, anxiety or stress, it is necessary to come to a state of rest. It's better to relax while sitting in comfortable position. In this case it is useful to carry out breathing exercises. You can allocate time for this while waiting in line.

It is advisable to choose loose-fitting, easy-to-remove clothing for visiting a cardiologist. This will speed up the event process.

When the examination period occurs during cold weather, the ECG room should be warm and comfortable. If a person gets cold, this can negatively affect the electrocardiogram.

Women should not use cream so as not to leave a greasy mark on the skin. This prevents the device from being tightly attached to the body.

What should you not take before the test?

A person should give up all tonic drinks. The list includes tea, coffee, energy cocktails, and especially those containing alcohol. This should be done no later than 4-6 hours before the start of the procedure. This does not apply to alcohol. You should not drink it for at least several days before the procedure. Energy drinks, which contain a considerable dose of caffeine, not only distort cardiograph readings, but also negatively affect the functioning of many organs.

It is not recommended to consume heavy or heavy food within an hour before the procedure. fatty foods. Eating spicy and salty foods is also not advisable. Large meals may cause shortness of breath and interfere with monitoring results. If skipping breakfast for some reason is not recommended or you simply don’t feel like it, you can have a light snack in small quantities.

Vasoconstrictor drugs are also contraindicated before the start of the session. Eye drops and nasal sprays are not used before the cardiogram procedure.

Just like stimulants, strong sedatives are also contraindicated. If a patient takes these medications, the doctor may misdiagnose bradycardia (or tachycardia in the case of stimulants).

Holter monitoring

Holter monitoring is a modern electrocardiogram method that allows it to be carried out 24 hours a day. The method is more effective than a one-time short-term procedure, the result of which can be influenced by many factors. Preparing a patient for a Holter ECG involves performing a number of simple measures. A person must understand that the study involves observing the functioning of the heart during a normal lifestyle. You need to carry on with your daily affairs, go to work and not try to influence the monitoring.

The Holter device is a small block with electrodes that are attached to the chest.

Clothing should not have metal parts. Metal jewelry will also have to be removed. Before using the device, you must water treatments, since this cannot be done during the study.

During monitoring you should avoid:

caffeine (coffee, strong tea, energy);
alcohol;
excessive physical activity;
swimming and bathing;
taking medications that affect cardiac function.

Application of ointments, creams and various cosmetics undesirable. As with a regular ECG, precautions must be taken. These include taking heart-stimulating drugs, stimulants nervous system, vasoconstrictors.

The abbreviation ECG stands for electrocardiogram. This functional method research, the essence of which is to determine the condition of the heart by changes in its electrical activity. This research method is by far the most common and is carried out in almost all medical institutions. All emergency teams are also equipped with an ECG machine. medical care.

Principle of the method

The human heart has a certain electrical activity. It has a generator of electrical nerve impulses (the sinus node in the right atrium), a conduction system (consists of nerve fibers and nodes through which the impulse spreads throughout the heart) and muscles (react to the nerve impulse by contracting). IN sinus node the impulse is generated at a certain frequency, conducted through the conduction system to the myocardium (heart muscle), which contracts at the appropriate frequency. Various pathological processes in the heart lead to a change in the generation or conduction of a nerve electrical impulse. The essence of electrocardiography is to record electrical impulses arising and passing into the heart from the surface of the body using special electrodes. The received pulses are amplified in the device and displayed on paper tape in the form of a curved line. Based on the changes on it, the doctor makes a conclusion about the presence or absence of changes in the heart and their nature. Actually, an electrocardiogram is graphic image electrical processes of the heart.

The ECG was first introduced into clinical medical practice by the Dutch scientist physiologist Willem Einthoven. He created the first cardiograph, which weighed more than 200 kg. For this he was awarded the Nobel Prize in 1924.

ECG of the heart refers to non-invasive research methods. This means that when it is carried out there is no damage to the skin or mucous membranes. To conduct the study, the patient undresses to the waist, electrodes are placed on his arms and chest, which record the electrical potential of the skin surface that occurs during heart activity. The examination itself lasts about 5-7 minutes. Thanks to high security and absence negative influence on the human body, ECG is widely used in children, pregnant and breastfeeding women.

Types of ECG

An electrocardiogram of the heart is most often performed at rest. To expand the diagnostic capabilities of this method functional research, a number of additional tests are currently being carried out:

calm state

Drug test - before performing an electrocardiogram, a person takes (or is administered intramuscularly, intravenously) a certain medicine, changing the activity of the heart.
Holter monitoring - the essence of this type of study is long-term recording (usually during the day) of the electrical activity of the heart. This makes it possible not to miss short-term changes in its work.

These additional types are carried out if using a regular ECG it is not possible to detect changes in the functioning of the heart.

Indications

There are 2 main groups of indications. ECG diagnostics various pathologies and preventive screening study. For diagnostic purposes, this study is carried out for the following diseases:

Preventive screening ECG is performed in the following cases:

An expert study of the heart capabilities of people in certain professions who have occupational hazard increased load on the heart, connected with necessity high concentration attention and speed of psychomotor reactions - drivers, sailors, pilots.
Age over 40 - in people older than this age high risk development of pathology, is carried out at least once a year.
On the eve of the surgical intervention or invasive therapeutic and diagnostic procedures.
Pregnant women for prevention and prevention possible problems during childbirth (this is physiological state provides heavy load on the heart).

Preventive screening tests help identify possible changes even before the stage of their clinical manifestations.

ECG results are displayed graphically in the form of a curve. During decoding, the doctor evaluates the height of the teeth, their width and intervals between them (each indicator is expressed numerically and has its own norm). He also evaluates complexes of several teeth that characterize the conduction of impulses in the atria or ventricles. Based on the results obtained, he identifies several summative indicators, which include:

Rhythm and heart rate.
Position of the electrical axis of the heart (spatial direction of the summing vector of electrical potentials).
Complexes of atrial and ventricular waves and intervals.

Based on the obtained indicators and changes in them, only a conclusion is made on the ECG (for example, signs on the ECG during myocardial infarction). The diagnosis of the disease is made only by the attending physician.

ECG has been used in medicine for more than 100 years. It is a very important research method used to diagnose many diseases. Due to its safety and information content, it can be performed on children and pregnant women.

Electrocardiography is the recording of bioelectric potentials that occur during contraction of the heart muscle. This method is accessible, does not require special preparation, and is safe for the patient. At the same time, the information received by the doctor can help in making a diagnosis of coronary artery disease, arrhythmia, and conduction disorders.

Read in this article

Operating principle of an electrocardiograph

An ECG recording device consists of electrodes that are attached to the patient's body, a galvanometer, an amplifier, a recorder and a lead switch. The impulses that are formed in the heart muscle must first be amplified, then they are perceived by the galvanometer. It converts electrical waves into mechanical vibrations.

The recorder records, using thermal paper recorders, a typical graphical curve called an electrocardiogram.

Using an ECG study, you can judge the condition of the heart muscle by the following indicators:

impulse conductivity;
rhythm of heart contractions;
enlargement of one or more parts of the heart;
blood supply to the myocardium;
areas of necrosis (infarction) their size, depth and duration of occurrence.

Clothing is selected in such a way that it is easy to attach electrodes to the skin of the ankles, wrists and chest.

On the day of the study, it is strictly prohibited to take alcoholic drinks, smoking, you need to give up sports and a hearty breakfast. The best drink is regular drinking water, weak tea or fruit juice.

In order to take an electrocardiogram, the patient is placed on a couch, medical worker places electrodes on the shins, wrists and chest. If there is difficulty breathing in a horizontal position, the procedure is performed while sitting.

Rules for the procedure

To ensure good contact between the skin and the electrode, the attachment site is degreased with ethyl alcohol and a special conductive gel is applied. After this, readings are taken using an ECG diagnostic device.

The whole procedure takes about 10 - 15 minutes.

In order to receive reliable result, you need to be in a calm, relaxed state, do not hold your breath. Muscle tremors from excitement or cold can lead to data distortion.

The generally accepted leads are 3 standard, 3 reinforced and 6 chest. Each lead will record at least 4 cardiac cycles. After this, the device is turned off, the electrodes are removed, and the functional diagnostics doctor is given a signed tape, which he must decipher.

For information on the ECG recording method, watch this video:

Are there any special features during pregnancy?

In the body of a pregnant woman, the load on the heart muscle changes, as it must provide blood supply to the fetus in the uterus. The electrocardiogram may show abnormalities that are not an indication of heart disease.

Therefore, starting from 3 - 4 months, when deciphering the testimony, an amendment is made for the presence of the gestation process.

When preparing and conducting the procedure itself, standard research techniques are used.

How to do an ECG for women

For women, the rules for installing electrodes are the same as for men. They should be located in the heart area, directly on the skin, so before performing an ECG, you must completely remove all clothing from the chest, including your bra. Please note that tights or stockings will interfere with attaching the sensors to the lower leg.

Interpretation of ECG indicators

On the tape, the curve obtained after taking the cardiogram has 5 teeth. They occur with sequential contraction of the atria and ventricles. The following designations are accepted:

The P wave is an indicator of the work of the right (first half) and left atrium.
P Q – interval of impulse passage to the ventricle along the Hiss bundle.
QRST - complex occurs during contraction of the ventricles, while the highest R wave reflects the excitation of the ventricular myocardium, and Q and S are the partitions between them, T - occurs during the period of myocardial recovery after systole.

Teeth and intervals

Normal in adults

A doctor can fully evaluate the electrocardiogram, since making a diagnosis requires knowing the symptoms of the disease and data from other research methods (blood tests, ultrasound, echocardiography). General characteristics assessed by a specialist healthy person the following:

The rhythm of contractions is from 60 to 80 per minute.
The size of the intervals should not exceed normal values, or be shorter than average values.
– normally R exceeds S in all leads except aVR, V1 - V2, sometimes V3.
The ventricular complex is no more than 120 ms.
T is positive and longer than the QRS complex.

ECG (normal)

During pregnancy

As the uterus grows, it raises the dome of the diaphragmatic septum and after 24 - 24 weeks the apex of the heart moves to the left. This is reflected in the electrocardiogram by an increase in the amplitude of R in the first, and S and Q in the third lead, the ventricular complex decreases along with the ST segment. Changes in conduction through the heart muscle are also associated with the influence of hormones produced by the placenta.

Characteristic features:

Shift of the heart axis to the left.
T biphasic and negative in the right chest leads.
The ventricular complex is wider than normal.
Rapid rhythm, single extraordinary contractions.

Respiratory arrhythmia in pregnant women

Deviations that the device can detect

By taking and interpreting an electrocardiogram, you can identify signs of the following diseases:

angina pectoris and heart attack;
type of arrhythmia, location of the pacemaker;
blockade due to decreased conductivity;
myocardial hypertrophy and its localization;
signs of myocarditis and pericarditis;
pulmonary embolism;
symptoms of pulmonary hypertension;
disorders of the electrolyte composition of the blood.

3rd degree AV block

Disadvantages of ECG examinations

Despite its high diagnostic value, a regular ECG cannot detect changes in heart function outside the time of its taking. Therefore, along with the traditional technique, the patient may be prescribed additional tests with physical activity.

Using this method, it is impossible to recognize heart murmurs, therefore, if structural defects of the valves or septa are suspected, phonocardiography or ultrasound of the heart should be performed.

If you plan to install a stent or shunt for myocardial ischemia, then it is required to determine the localization of the narrowing of the coronary arteries. Tumor processes are diagnosed by X-ray or MRI examination.

Current patient questions

The ECG method is traditional and is used long time in medical practice. But patients often have concerns about its use. The most common questions:

Thus, the ECG is a time-tested accessible view diagnostics, which is used both for preventive examination during clinical examination and for making a diagnosis in the presence of complaints of cardiac dysfunction. Such research is safe and informative.

The essence of the method

Electrocardiography (ECG) - method medical research heart, which is based on recording electrical potentials arising during cardiac activity. Special sensors are placed on the patient’s body, and the signals read with their help are displayed on paper or film using a recorder. The result is a graph called an electrocardiogram. ECG readings play important role in the diagnosis of heart diseases.

Modern ECG devices - electrocardiographs - are portable and stationary. Portable electrocardiographs are used by ambulance crews, employees of small medical offices and clinics. A stationary electrocardiograph is less susceptible to interference and gives more accurate readings. Such devices are used in larger medical institutions. Stationary and portable electrocardiographs may differ in functionality and ease of use. Latest models electrocardiographs can store hundreds of ECGs in memory and issue a preliminary diagnosis automatically.

When is electrocardiography necessary?

For prevention and early detection cardiovascular diseases It is recommended to do an ECG at least once a year. Indications for an ECG are also:

chest pain;
dyspnea;
arrhythmia;
deterioration in general well-being after physical or emotional stress;
transferred somatic or infectious diseases threatening complications;
upcoming surgery;
first and third trimesters of pregnancy;
monitoring the condition of seriously ill patients.

An ECG examination is safe because it does not affect the human body, but only registers electrical impulses created by the heart. There are no contraindications for performing an ECG.

Carrying out an ECG: features of the procedure

It is recommended to carry out ECG measurements in warm rooms, away from possible sources of electrical interference. The patient should be undressed to the waist, the lower legs should be freed from clothing. Sensors (leads) in general case are installed on the chest and limbs. To ensure better skin contact with the sensors, special electrically conductive gels and solutions are used. Muscle tremors in a cold room or insufficient contact of the sensors with the skin can distort the readings. The study is carried out with the patient lying down, less often - standing. At least 6-10 cardiac cycles are recorded. Although special training an ECG is not required; the most correct results can be obtained two or more hours after eating (on an empty stomach).

The ECG technique has the following varieties:

universal ECG with 12 leads (3 standard, 3 unipolar and 6 chest);
ECG with additional chest leads for detailed diagnosis of cardiac rhythm and conduction disorders;
ECG with leads from internal organs– for example, intraesophageal;
Holter monitoring using special device, which is installed on the patient for a day for continuous readings;
ECG with physical or drug stress - to assess the heart's response to possible medical prescriptions.

Research results

The cardiogram is a periodically repeating complex of teeth directed up and down. The waves on the ECG indicate in Latin letters, each of which is assigned to a specific area of the heart. The same teeth in the readings of different sensors may have different sizes.

Excitation of the heart muscle begins from the atria. On the ECG this is displayed as a P wave. Normally, it has a height of 1-2 mm and a duration of 0.08-0.1 s.
The distance from the beginning of the P wave to the Q wave (PQ interval) demonstrates the time it takes for excitation to propagate from the atria to the ventricles. Normally this is 0.12-0.2 s.
Ventricular excitation is reflected by the QRS wave complex. Its normal duration is 0.06-0.1 s.
When the excitation of the ventricles decreases, the T wave is recorded. The ST and PQ intervals normally look similar and differ in amplitude by no more than 1 mm.
In one cardiac cycle the distance between the two nearest R waves is taken. By counting the number of these cycles in one minute, you can get the heart rate.
The TR interval corresponds to the relaxed state of the heart muscle (diastole), at which time a straight line is recorded. During cardiac arrest, the ECG is a solid straight line without any teeth.
Based on the amplitudes of the teeth, the position of the so-called electrical axis of the heart is calculated, which, as a rule, coincides with the geometric axis of the heart. The direction of the electrical axis shows the correct location of the heart.

As a result of the analysis of the cardiogram, it is possible to determine the condition of the heart as a whole, functional state myocardium and heart rate. A superficial analysis of ECG data can be performed by a doctor of any specialty. To do this, it is enough to imagine a normal ECG of the heart, as well as typical deviations - for example, during a heart attack.

The latest models of electrocardiographs perform part of the decoding automatically. However, a full analysis ECG results Only a qualified doctor can determine the electrical axis of the heart and describe the identified pathologies.

Interpretation of the ECG should be carried out taking into account the medical history. For example, in pregnant women, the electrical axis of the heart may be horizontal due to the fact that the growing fetus puts pressure on the heart and displaces it. The horizontal electrical axis of the heart is normal during pregnancy, but may indicate the presence of pathology in other cases.

Examples of ECG conclusions:

The heart rhythm is sinus, regular, heart rate 84 beats. in 1 min. Normal position of the electrical axis of the heart.
The heart rhythm is sinus, regular. Heart rate 76 beats. in 1 min. Horizontal electrical axis of the heart. Signs of left ventricular hypertrophy.

Cost of electrocardiography

For such a simple and short-term procedure as electrocardiography, the price is usually affordable. Average cost An ECG with interpretation in Moscow costs 1,200 rubles.

Where can I get an ECG?

When choosing where to sign up for an ECG, give preference to modern medical centers that have the latest equipment and provide comfortable conditions for all procedures. All types of ECG, including 24-hour Holter monitoring, are available in the ABC Medicine network of clinics. Clients especially note professional skills specialists of these medical institutions in working with children, for whom taking an electrocardiogram becomes one of the interesting moments of communication in game form. ABC Medicine clinics are conveniently located in the center and southwest of Moscow.

How is an ECG of the heart done?

If a person begins to worry about his heart, the first thing the doctor recommends is to undergo an ECG. Thanks to the data obtained using an electrocardiogram, you can see the overall picture of the heart and prescribe the correct treatment.

Why does the cardiologist send the patient for an ECG every time before prescribing treatment? Regardless of the patient’s age and the nature of the complaints about the heart function, the first thing the specialist does is to prescribe the patient to undergo an electrocardiogram procedure. Indeed, with the help of the data obtained after this test, it is possible to determine abnormalities in the functioning of the heart and make the most correct diagnosis.

History of the ECG.

In 1856, German scientists R. Kölliker and I. Müller, through research, discovered that the heart of an animal during its work is capable of producing a small amount of electricity. Based on this discovery, scientists made a device with which they began to record and study in detail the obtained indicators. At first, scientists worked with animals that were previously cut to have direct access to the work of the heart, and by 1873 the device was so improved that it could take measurements of heart function from the surface of the body.

After the death of the discoverers, the baton passed over the work this drug The Eindhoven scientist took it into his hands, and it was thanks to his developments that the ECG device acquired the form in which it is used before today, virtually unchanged.

Working principle of ECG.

The electrocardiograph consists of such main parts as: a galvanometer, an amplification system, a lead switch and a recording device. Those small electrical impulses that arise in the patient's heart are sensed by electrodes and then amplified, thereby activating the galvanometer. Thus, changes occur in the magnetic field, this data is transmitted to a recording device, and with the help of a special tape that moves at a certain speed, a diagram of the heart’s functioning can be obtained. The circuit consists of teeth that differ in size; the recording itself depends on the impulses that the heart sends during its work.

Exists the whole system correct reading of the received record. Through research, standards for height and duration have been developed for each tooth; any deviation from the established standards indicates the presence of problems of a certain nature; based on this knowledge, a specialist can make the most accurate diagnosis.

How is an ECG performed?

If the patient is scheduled for an electrocardiogram, then there are no special preparations before undergoing this survey no need to do it. A person lies down on a couch, a specialist attaches special electrodes with wires to the patient’s ankles, hands and chest; these wires go to a small device that directly takes measurements of heart impulses. The device produces a tape with a diagram and, based on the results obtained after this diagnosis, the specialist prescribes further treatment. The places where the electrodes are attached to the body are pre-lubricated with a small amount of special gel. The recording procedure itself lasts from 4 to 7 minutes. Heart impulses are measured while the patient is at rest and breathing evenly.

In order to get the most correct ECG indicators, the following recommendations should be observed: indicators are taken from a patient who is in in perfect condition rest, preferably before recording, first lie down on the couch for at least five minutes; - the examination is carried out no earlier than 2 hours after eating;

The patient should not be cold in the room where the electrocardiogram is taken, otherwise physiological tremors may affect the heart's pattern and cause an incorrect recording of the cardiogram.

What does an ECG determine?

Using an electrocardiogram, you can determine: how often and regularly the heart contractions occur; - acute or chronic damage to the myocardium. Are there any disturbances in the metabolism of potassium, calcium or magnesium in the body; - the cause of pain in the heart area (does this relate directly to the work of the heart or is it simply a pinched nerve). General condition of the heart muscle and its walls (enlarged or normal) ;- working condition a pacemaker implanted in the heart.

Disadvantages of ECG taken at rest.

It is impossible to detect diseases such as heart rhythm disturbances or coronary heart disease; this will require an ECG of the heart recorded during exercise or 24-hour ECG monitoring. - small deviations shown in the recording of heart function on an ECG tape may not be pronounced and may be interpreted by a specialist as normal.

Bicycle ergometry.

The process of recording an ECG during dosed physical activity is called bicycle ergometry. It is performed either using a special exercise bike or using a special treadmill. Using developed tests that the patient performs during an electrocardiogram measurement, it is possible to determine: - reaction cardiovascular system for moderate physical activity; - degree of endurance. To most accurately determine the time for recovery of cardiac activity and blood pressure after cessation of physical activity. Myocardial ischemia, even without pain symptoms. Are there any heart rhythm disturbances associated with physical activity. Reason pain in the region of the heart, whether they are related to coronary blood flow or due to non-cardiac causes.

The advantage of this examination is that the specialist has the opportunity to most adequately assess the dynamics of the disease and the effectiveness of the prescribed treatment.

Method ECG diagnostics absolutely harmless to human health at any age (can even be prescribed to infants). it does not expose the patient to radiation, is painless and does not require special preparation.

The article “How is an ECG of the heart done? "and other medical articles on the topic "Diseases of the heart and blood vessels" on the IOD website.

ECG guarding the heart

Day and night, our “fiery engine”—the heart—works tirelessly. We can learn about its secrets and complex activities with the help of an informative and accessible test - an ECG.

When we go to a doctor with a complaint of heart pain, the first thing he suggests is to do an electrocardiogram. The ECG procedure is simple at first glance. No pain, no radiation.

The patient sits comfortably on a couch and electrodes with wires leading to a small machine are attached to his wrists, ankles and chest. It hums quietly, clicks and throws out meters of paper tape covered in fancy squiggles. And on that tape are written all the secrets of the heart. What can an ECG do?

— Determine the frequency and regularity of heart contractions.

— Identify acute or chronic myocardial damage.

— Report metabolic disorders of potassium, calcium, magnesium.

— Detect intracardiac conduction disturbances.

- Provide information about non-cardiac diseases, such as pulmonary embolism.

Excursion into history

When did this diagnostic method appear? In 1856, two German scientists - R. Kölliker and I. Müller - discovered that the heart produces a certain amount of electricity during its work. And they created a device that could record these indicators.

It must be said that at that time scientists were conducting research on animals, working on an open heart. And only in 1873, after the device was improved, it became possible to record heart signals from the surface of the body.

But the apparatus for taking an ECG the way we are used to seeing it was created only at the beginning of the 20th century.

The Eindhoven scientist received the Nobel Prize for his invention. And all cardiologists in the world still use his developments without adding anything new.

ABC of ECG

The main parts of an electrocardiograph are a galvanometer, an amplification system, a lead switch and a recording device.

Electrical potentials arising in the heart are sensed by electrodes, amplified, and driven by a galvanometer. Changes magnetic field are transmitted to a recording device and reflected on a special tape moving at a certain speed.

All heart impulses are recorded in the form of waves of varying sizes and durations.

For each tooth and segment, normal duration and height limits have been developed. And based on the totality of the deviations found, a specialist doctor can make an accurate diagnosis.

Running for health

What information can be obtained after bicycle ergometry?

Dyatinyuk D.

Recording an ECG against the background of dosed physical activity is called bicycle ergometry. For testing, a bicycle ergometer is used - a special bicycle, and sometimes a treadmill, i.e. treadmill. Load tests allow you to:

— determine the response of the cardiovascular system to physical activity;

- find out the degree of endurance of the body;

— track the recovery time of cardiac activity and blood pressure after cessation of exercise;

— identify myocardial ischemia, including painless;

— detect heart rhythm disturbances associated with physical activity;

- identify the connection between chest pain and the state of coronary blood flow or the absence of such a relationship (after all, pain can also be caused by non-cardiac causes).

The advantage of bicycle ergometry is that such an examination makes it possible to objectively assess the dynamics of the development of the disease and the adequacy of the treatment.

How to do an ECG correctly

In order for the resting ECG to be accurate, the following rules must be followed.

1. The examination should be carried out with quiet breathing - for this you need to rest for at least 10 minutes before the procedure.

2. An ECG is performed no earlier than 2 hours after meals and physiotherapeutic procedures.

3. The room should not be cold. If you get hit muscle tremors, then vibration can distort the results of the study.

"Chronicle" of the heart

What is a Holter ECG?

Shorkina N.

The ECG is without a doubt a very powerful diagnostic tool. However, it is worth remembering that this method also has weaknesses. One of them is the short duration of the recording - about 20 seconds. And if a person suffers from arrhythmia, then at the time of recording it may be absent. In addition, recordings are usually made at rest and not during normal activities. Therefore, sometimes, in order to expand the diagnostic capabilities of the ECG, they resort to long-term recording - the so-called Holter ECG monitoring.

The essence of the procedure is this. A person does his usual things during the day. And a small recorder is attached to his body, which records an electrocardiogram around the clock. Subsequent data processing allows you to accurately diagnose and select the necessary course of treatment.

Electrocardiography is an accessible and informative procedure for diagnosing cardiac pathologies. The essence of the method is to record electrical impulses, the occurrence of which is due to the rhythmic alternation of contractions and relaxations of the heart muscle over a certain time range.

An electrocardiograph (a special medical device) records impulses coming from sensors mounted on the body and converts them into a graph. Such a graphic image is called an electrocardiogram, and is subject to further decoding by a cardiologist. Since ECGs are performed in hospitals and at home, there are stationary and portable cardiographs.

The main components of the device are:

electrodes placed on a person’s arms, legs and torso;
switch-regulator;
signal amplifier;
filter against network interference.

Modern cardiographs have high sensitivity to the bioelectrical activity of the heart muscle, and the accuracy of the transmission of impulse oscillations.

Purpose and objectives of the ECG

An electrocardiogram is taken to correct diagnosis heart diseases. Using this procedure, the following parameters are assessed:

rhythm of heart contractions;
possible damage and completeness of blood supply to the muscular middle layer of the heart (myocardium);
disturbances of magnesium and potassium balance;
hypertrophy (thickening) of the heart walls;
areas of infarction (necrosis).

Reasons to get tested

An ECG is done in the following cases:

chronically high blood pressure;
making a diagnosis for chest pain;
obesity;
jumping heart rate.

Symbols on the graph

Graphic recording of an ECG is a broken line, the sharp corners (teeth) of which are located above and below the horizontal line on which time cycles are recorded. The teeth show the depth and frequency of rhythmic changes. The recovery phase between contractions of the heart muscle is designated by the Latin T. Excitation or depolarization of the atria - R.

Correct location electrocardiograph sensors - the basis for taking an ECG

The recovery cycle of distant ventricles of the heart is U. The state of excitation of the ventricles is reflected by the Q, R, S waves. The intermediate distances from one tooth to another are called segments on the ECG (ST, QRST, TP). The fragment of the graph, the capturing segment and the adjacent tooth is called the pulse interval.

Leads or circuits that record the difference in potential indicators transmitted by the electrodes are divided into three groups:

standard. I – the difference in data on the left and right hand, II – the difference in potential on the right hand and left leg, III – on the left hand and leg;
reinforced. AVR – from right hand, AVL – from the left hand, AVF – from the left leg;
chest Six leads are located between the ribs (V1, V2, V3, V4, V5, V6).

The entries on the graph reflect the work of the heart in each lead, which allows for a more detailed analysis of the work of all parts of the organ.

Basic principles of electrocardiographic diagnostics

Algorithm of actions medical specialists during the procedure:

preliminary preparation of the patient for examination;
correct installation of electrodes on the body;
control of the cardiograph;
removing sensors;
decoding the results.

The preparatory stage consists of conveniently positioning the patient horizontally on his back, on a medical couch. In case of difficulty breathing, the instructions for the procedure allow for a sitting position. Next, the areas of the skin where the electrodes are attached are treated with alcohol or another antiseptic, and a medical gel with conductive properties is applied to them. The technique of taking an ECG largely depends on the correct placement of the electrodes on the body of the subject.

According to the electrode application pattern, the patient's wrists, ankles and torso are involved in the process. For single-channel recording, one chest electrode is used, for multi-channel recording - six.

The ECG manual determines the exact location of the sensors on the human body. The electrodes are installed on the legs and arms in a clockwise direction, starting from the right upper limb. For convenience, the sensors are marked by color. Red is for the right hand, yellow is for the left hand, green is for the left leg, black is for the right leg.

Electrodes that record the chest leads are located between the ribs and in the line of the armpits as follows:

right edge of the chest, fourth intercostal space – electrode V1. Symmetrically to it, V2 - electrode is installed on the left side;
left parasternal (parasternal) arch, near the fifth rib, in the interval between V2 and V4 - electrode V3;
the intersection of the left vertical line, conventionally drawn on the anterior surface of the chest through the projection of the middle of the clavicle (midclavicular line) and the fifth intercostal space - electrode V4;
left axillary anterior line – electrode V5;
left middle axillary line – electrode V6.

Experts rely on these identification lines

During ECG, electrodes V4, V5 and V6 are applied at the same horizontal level. It is unacceptable to apply electrodes in a different order. The accuracy of the diagnosis depends on this. If a deep analysis of cardiac activity is necessary, it is customary to use the Slopak ECG technique. In this case, additional V7, V8, V9 leads are installed.

Patient Responsibilities

Before planned ECG patient must exclude active physical activity, don't be nervous. It is necessary to give up alcohol and eat food no later than two hours before the examination. Do not take medications that tonic or depress the functioning of the central nervous system (central nervous system), cardiac stimulants and sedatives. During electrocardiography, breathing should be monitored.

A smooth and calm breathing rhythm helps obtain accurate data. Otherwise, the cardiogram readings may be biased. If there is a need for emergency medical care, a cardiac cardiogram is done without preparation, and in the patient’s health condition of any severity. People aged 40+ are recommended to have an ECG annually. In the presence of chronic heart disease, the frequency of the procedure is determined by the attending physician.

Brief standard indicators of the cardiogram

Graphic reflection on the cardiograph tape reflects the work of the heart. Sharp angles or teeth pointing upward from the main horizontal line are positive, pointing downward is negative. Electrocardiogram data is decoded according to standards. For the adult population, they take as a basis the following indicators:

P wave – positive;
Q wave – negative;
S wave – negative, below the R wave;
T-wave – positive;
the frequency or rhythm of heart contractions varies between 60–80 units;
QT interval – no more than 450 milliseconds;
QRS interval width is about 120 milliseconds;
EOS (electrical axis of the heart) – not deviated.

The basis of cardiac dysfunction on a millimeter chart is determined by counting cells from one R wave to another. Different distances between the R-waves indicate arrhythmia (changes in the frequency, regularity and sequence of heart contractions). The heart rate is below normal due to the presence of bradycardia. A rapid heart rate diagnoses tachycardia. The correct heart rhythm is called sinus.

Cardiogram graph indicating the main parameters

Only a qualified specialist - a therapist or cardiologist - can decode a graphic image on a tape or its photo. Don't self-diagnose cardiac diseases.

Possible shortcomings of the examination

The ability to correctly take an ECG is reduced by the following reasons:

interference in electrical network;
excitement of the subject;
poor sensor contact;
human factor(careless attitude nurse, which made incorrect application of electrodes or awkward filling of the device with tape).

Some disadvantages of ECG:

lack of diagnosis for one-time cardiac disorders. The procedure produces indicators based on the “here and now” principle. This is only good for stable heart failure;
inability to identify defects, murmurs and tumors. For a full examination, it is necessary not only to take an ECG, but also to do.

Electrocardiography is an accessible and fast diagnostic method. You should not ignore discomfort in the chest area and heart pain. You can undergo the procedure at any age in every district hospital.