Deciphering ekg vertical. Deciphering the indicators of ecg. Prongs and intervals

The heart is the most important human organ. With its dysfunction, the whole body suffers. Electrocardiography is used to detect various cardiovascular pathologies. It uses a device that captures the electrical impulses of the heart - an electrocardiograph. ECG interpretation allows you to see the main deviations in the work of the organ on the graphic curve, which in most cases helps to make a diagnosis without additional studies, prescribe the necessary treatment.

What concepts are used in deciphering

Deciphering an ECG is a rather complicated process that requires deep knowledge from a specialist. During the assessment of the state of the heart, cardiogram indicators are measured mathematically. In this case, concepts such as sinus rhythm, heart rate, electrical conductivity and electrical axis, pacemakers and some others are used. By evaluating these indicators, the doctor can clearly determine some parameters of the functioning of the heart.

Heart rate

Heart rate is the specific number of heartbeats in a given period of time. Usually an interval of 60 seconds is taken. On the cardiogram, heart rate is determined by measuring the distance between the highest teeth (R - R). The recording speed of the graphic curve is typically 100 mm/s. By multiplying the recording length of one mm by the duration of the segment R - R, the heart rate is calculated. In a healthy person, the number of heartbeats should be 60 - 80 beats per minute.

Sinus rhythm

Another concept included in the decoding of the ECG is the sinus rhythm of the heart. During the normal functioning of the heart muscle, electrical impulses arise in a special node, then propagate to the region of the ventricle and atrium. The presence of sinus rhythm indicates the normal functioning of the heart.

The cardiogram of a healthy person should show the same distance between the R waves throughout the recording. A deviation of 10% is allowed. Such indicators indicate the absence of arrhythmia in humans.

Conduction paths

This concept defines such a process as the propagation of electrical impulses through the tissues of the heart muscle. Normally, impulses are transmitted in a certain sequence. Violation of the order of their transfer from one pacemaker to another indicates organ dysfunction, the development of various blockades. These include sinoatrial, intraatrial, atrioventricular, intraventricular blockade, as well as Wolff-Parkinson-White syndrome.

On an ECG, a specialist can see a violation of cardiac conduction

Electrical axis of the heart

When deciphering the cardiogram of the heart, the concept is taken into account - the electrical axis of the heart. This term is widely used in cardiology practice. When deciphering an ECG, this concept allows a specialist to see what is happening in the heart. In other words, the electrical axis is the totality of all biological and electrical changes within an organ.

An electrocardiogram allows you to visualize what is happening in a specific area of ​​\u200b\u200bthe heart muscle using a graphic image obtained by transmitting impulses from electrodes to a special device.

The position of the electrical axis is determined by the doctor using special diagrams and tables or by comparing QRS complexes that are responsible for the process of excitation and contraction of the heart ventricles.

If the ECG indicators indicate that in lead III the R wave has a lower amplitude than in lead I, we are talking about a deviation of the cardiac axis to the left. In the event that in the III lead the R wave has a greater amplitude than in the I lead, it is customary to speak of a deviation of the axis to the right. Normal values ​​in the cardiogram table - the R wave is the highest in lead II.

Prongs and intervals

On the cardiogram itself, obtained during the study, the teeth and intervals are not indicated. They are needed only for a specialist doing decryption.

Teeth:

• P - determines the beginning of the contraction of the atrial region;
• Q, R, S - belong to the same species, coincide with the contraction of the ventricles;
• T - the time of inactivity of the ventricles of the heart, that is, their relaxation;
• U - rarely noted on the cardiogram, there is no consensus about its origin.

For ease of interpretation, the cardiogram is divided into intervals. On the tape, you can see straight lines that run clearly in the middle of the tooth. They are called isolines or segments. When making a diagnosis, the indicators of the P-Q and S-T segments are usually taken into account.

In turn, one interval consists of segments and teeth. The length of the interval also helps to assess the overall picture of the functioning of the heart. Intervals - P - Q and Q - T have diagnostic significance.

Reading a cardiogram

How to decipher the cardiogram of the heart? This question is asked by many patients who had to deal with the procedure of electrocardiography. It is very difficult to do it yourself, because decrypting data has a lot of nuances. And if in your cardiogram you read certain violations of the activity of the heart, this does not at all mean the presence of a particular disease.

A cardiologist is reading a cardiogram

teeth

In addition to taking into account intervals and segments, it is important to monitor the height and duration of all teeth. If their fluctuation does not deviate from the norm, this indicates a healthy functioning of the heart. If the amplitude is rejected, we are talking about pathological conditions.

The norm of the teeth on the ECG:

• R - should have a duration of no more than 0.11 s., height within 2 mm. If these indicators are violated, the doctor can make a conclusion about the deviation from the norm;
• Q - should not be higher than a quarter of the R wave, wider than 0.04 s. Special attention should be paid to this tooth, its deepening often indicates the development of a myocardial infarction in a person. In some cases, tooth distortion occurs in people with severe obesity;
• R - when deciphered, it can be traced in leads V5 and V6, its height should not exceed 2.6 mV;
• S is a special tooth for which there are no clear requirements. Its depth depends on many factors, for example, weight, sex, age, position of the patient's body, but when the tooth is too deep, we can talk about ventricular hypertrophy;
• T - must be at least a seventh of the R wave.

In some patients, after the T wave, a U wave appears on the cardiogram. This indicator is rarely taken into account when making a diagnosis; it does not have any clear norms.

Intervals and segments also have their normal rates. If these values ​​are violated, a specialist usually gives a referral to a person for further research.

Normal indicators:

• the ST segment should normally be located directly on the isoline;
• the QRS complex should not have a duration of more than 0.07 - 0.11 s. If these indicators are violated, various pathologies of the heart are usually diagnosed;
• the PQ interval should last from 0.12 milliseconds to 0.21 seconds;
• The QT interval is calculated taking into account the heart rate of a particular patient.

Important! The ST segment in leads V1 and V2 sometimes runs slightly above the isoline. The specialist must take into account this feature when deciphering the ECG.

Decryption Features

To record a cardiogram, a person is attached to the body with special sensors that transmit electrical impulses to an electrocardiograph. In medical practice, these impulses and their paths are called leads. Basically, during the study, 6 main leads are used. They are denoted by the letters V from 1 to 6.

We can distinguish the following rules for decoding a cardiogram:

• In lead I, II, or III, you need to determine the location of the highest region of the R wave, and then measure the gap between the next two teeth. This number should be divided by two. This will help determine the regularity of the heart rate. If the gap between the R waves is the same, this indicates a normal contraction of the heart.
• After that, you need to make a measurement of each tooth and interval. Their rules are described in the article above.

Most modern devices automatically measure heart rate. With older models, this has to be done manually. It is important to consider that the ECG recording speed is usually 25-50 mm/s.

Heart rate is calculated using a special formula. At a cardiogram recording speed of 25 mm per second, the interval distance R - R should be multiplied by 0.04. In this case, the interval is indicated in millimeters.

At a speed of 50 mm per second, the interval R - R must be multiplied by 0.02.

For ECG analysis, 6 out of 12 leads are usually used, since the next 6 duplicate the previous ones.

Normal values ​​in children and adults

In medical practice, there is the concept of the norm of the electrocardiogram, which is characteristic of each age group. Due to the anatomical features of the body in newborns, children and adults, the study indicators are somewhat different. Let's consider them in more detail.

ECG norms in adults can be seen in the figure.

A child's body is different from an adult's. Due to the fact that the organs and systems of the newborn are not fully formed, electrocardiography data may differ.

In children, the mass of the right ventricle of the heart prevails over the left ventricle. Newborns often have a high R wave in lead III and a deep S wave in lead I.

The ratio of the P wave to the R wave in adults is normally 1:8, in children the P wave is high, often more pointed, in relation to R is 1:3.

Due to the fact that the height of the R wave is directly related to the volume of the ventricles of the heart, its height is lower than in adults.

In newborns, the T wave is sometimes negative, it may be lower.

The PQ interval appears to be shortened, as in children the speed of impulse conduction along the conduction system of the heart is higher. This also explains the shorter QRS complex.

At preschool age, electrocardiogram parameters change. During this period, there is still a deviation of the electrical axis of the heart to the left. The mass of the ventricles increases, respectively, the ratio of the P wave to the R wave decreases. The contraction force of the ventricles increases, the R wave becomes higher, the rate of impulse transmission through the conduction system decreases, which leads to an increase in the QRS complex and the PQ interval.

In children, the following indicators should normally be observed:

Important! Only after 6 - 7 years, complexes, teeth and intervals acquire a value that is inherent in an adult.

What affects the accuracy of indicators

Sometimes the results of the cardiogram may be erroneous, differ from previous studies. Errors in results are often associated with many factors. These include:

• improperly attached electrodes. If the transducers are loose or move during an ECG, this can seriously affect the results of the exam. That is why the patient is recommended to lie still for the duration of the entire period of taking the electrocardiogram;
• foreign background. The accuracy of the results is often affected by extraneous devices in the room, especially when ECG is performed at home using mobile equipment;
• smoking, drinking alcohol. These factors affect blood circulation, thereby changing the parameters of the cardiogram;
• food intake. Another reason that affects blood circulation, respectively, on the correctness of the indicators;
• emotional experiences. If during the study the patient is worried, this may affect the heart rate and other indicators;
• Times of Day. When conducting a study at different times of the day, the indicators may also differ.

The specialist must necessarily take into account the above nuances when deciphering the ECG, if possible, they should be excluded.

Dangerous diagnoses

Diagnosis using electrical cardiography helps to identify many heart pathologies in a patient. Among them are arrhythmia, bradycardia, tachycardia and others.

Cardiac conduction disorder

Normally, the electrical impulse of the heart passes through the sinus node, but sometimes other pacemakers are also noted in a person. In this case, symptoms may be completely absent. Sometimes conduction disturbance is accompanied by fatigue, dizziness, weakness, jumps in blood pressure and other signs.

With an asymptomatic course, special therapy is often not required, but the patient should undergo regular examinations. Many factors can negatively affect the work of the heart, which entails a violation of depolarization processes, a decrease in myocardial nutrition, the development of tumors and other complications.

Bradycardia

A common type of arrhythmia is bradycardia. The condition is accompanied by a decrease in heart rate below normal (less than 60 beats per minute). Sometimes such a rhythm is considered the norm, which depends on the individual characteristics of the organism, but more often bradycardia indicates the development of one or another pathology of the heart.

Features of the ECG in a patient with bradycardia can be seen in the figure.

There are several types of disease. With a latent course of bradycardia without obvious clinical signs, therapy is usually not required. In patients with pronounced symptoms, the underlying pathology that causes heart rhythm disturbance is treated.

Extrasystole

Extrasystole is a condition accompanied by an untimely contraction of the cardiac departments. In a patient, extrasystole causes a feeling of a strong cardiac impulse, a feeling of cardiac arrest. In this case, the patient experiences fear, anxiety, panic. The prolonged course of this condition often leads to impaired blood flow, entails angina pectoris, fainting, paresis and other dangerous symptoms.

It is believed that with extrasystole no more than 5 times per hour there is no health hazard, but if attacks occur more often, appropriate treatment should be carried out.

sinus arrhythmia

The peculiarity of this violation lies in the fact that when the heart rate changes, the work of the organ remains coordinated, the sequence of contraction of the heart departments is normal. Sometimes in a healthy person on the ECG, sinus arrhythmia can be observed under the influence of factors such as food intake, excitement, physical activity. In this case, the patient does not have any symptoms. Arrhythmia is considered physiological.

In other situations, this violation may indicate pathologies such as coronary heart disease, myocardial infarction, myocarditis, cardiomyopathy, heart failure.

Patients may experience symptoms in the form of headaches, dizziness, nausea, heart rhythm disturbances, shortness of breath, chronic fatigue. Treatment of sinus arrhythmia involves getting rid of the underlying pathology.

The norm and signs of arrhythmia on the cardiogram

Important! In children, sinus arrhythmia often occurs during adolescence, may be associated with hormonal disorders.

Tachycardia

With tachycardia, the patient has an increase in heart rate, that is, more than 90 beats per minute. Normally, tachycardia develops in people after strong physical exertion, sometimes stress can become the cause of a heartbeat. In a normal state, the rhythm returns to normal without health consequences.

It is important to note that tachycardia is not an independent disease and does not occur on its own. This violation always acts as a secondary symptom of some pathology. This means that treatment should be directed at the disease that caused the increase in heart rate.

One of the forms of coronary disease that occurs in the acute stage is myocardial infarction. The condition is accompanied by the death of myocardial tissue, often leading to irreversible consequences.

The course of a heart attack usually takes place in several stages, each of which is characterized by a change in ECG parameters:

• the early stage lasts 6-7 days. In the first few hours, the cardiogram shows a high T wave. Over the next three days, the ST interval increases, the T wave descends. With timely treatment at this stage, it is possible to completely restore myocardial function;
• appearance of dead areas. The cardiogram shows an increase and expansion of the Q wave. Medical therapy here involves the restoration of areas with tissue necrosis;
• subacute period. This stage lasts from 10 to 30 days. Here the cardiogram begins to return to normal. In place of the affected areas of the myocardium, scars appear;
• scarring stage. Its duration takes from 30 days or more, accompanied by complete scarring of tissues. Sometimes patients have cardiosclerosis and other changes.

In the picture you can see the change in ECG parameters during the disease.

Cardiogram indicators in myocardial infarction at different stages

Electrocardiography is a complex, but at the same time very informative diagnostic method that has been used in medical practice for decades. It is quite difficult to independently decipher the graphic image obtained during the study. The interpretation of the data should be handled by a qualified physician. This will help to accurately diagnose, prescribe the appropriate treatment.

An electrocardiographic study is a fairly simple and effective diagnostic method used by cardiologists around the world to study the activity of the heart muscle. The results of the procedure in the form of graphs and digital symbols, as a rule, are transferred to specialists for further data analysis. However, in the case of, for example, the absence of the right doctor, the patient has a desire to independently decipher the indicators of his heart.

Preliminary interpretation of the ECG requires knowledge of special basic data, which, due to their specificity, are not subject to everyone. In order to make correct calculations of the ECG of the heart for a person who is not related to medicine, it is necessary to familiarize yourself with the basic principles of processing, which are combined for convenience into the appropriate blocks.

Familiarization with the basic elements of a cardiogram

You should know that the interpretation of the ECG is carried out thanks to elementary, logical rules that can be understood even by an ordinary layman. For a more pleasant and calm perception of them, it is recommended to start familiarizing yourself first with the simplest principles of decoding, gradually moving to a more complex level of knowledge.

Ribbon layout

The paper, which reflects data on the functioning of the heart muscle, is a wide ribbon of a soft pink hue with a clear “square” marking. The larger quadrilaterals are formed from 25 small cells, and each of them, in turn, equates to 1 mm. If a large cell is filled with only 16 dots, for convenience, you can draw parallel lines along them and follow similar instructions.

The horizontals of the cells indicate the duration of the heartbeat (sec), and the verticals indicate the voltage of individual ECG segments (mV). 1 mm is 1 second of time (in width) and 1 mV of voltage (in height)! This axiom must be kept in mind throughout the entire period of data analysis, later its importance will become obvious to everyone.

The paper used allows you to correctly analyze the time intervals

teeth and segments

Before moving on to the names of specific departments of the gear graph, it is worth familiarizing yourself with the activity of the heart itself. The muscular organ consists of 4 compartments: the 2 upper ones are called the atria, the 2 lower ones are called the ventricles. Between the ventricle and the atrium in each half of the heart there is a valve - a leaflet responsible for accompanying blood flow in one direction: from top to bottom.

This activity is achieved due to electrical impulses that move through the heart according to the "biological timetable". They are sent to specific segments of the hollow organ using a system of bundles and nodes, which are miniature muscle fibers.

The birth of the impulse occurs in the upper part of the right ventricle - the sinus node. Further, the signal passes into the left ventricle and excitation of the upper parts of the heart is observed, which is recorded by the P wave on the ECG: it looks like a gentle inverted cup.

After the electric charge reaches the atrioventricular node (or AV node), which is located almost at the junction of all 4 pockets of the heart muscle, a small “point” appears on the cardiogram, pointing down - this is the Q wave. Just below the AV node there is the following item the purpose of the impulse is the bundle of His, which is fixed by the highest tooth R among others, which can be represented as a peak or mountain.

Having overcome half of the way, an important signal rushes to the lower part of the heart, through the so-called legs of the bundle of His, outwardly resembling the long tentacles of an octopus that hug the ventricles. The conduction of the impulse along the branched processes of the bundle is reflected in the S wave - a shallow groove at the right foot of R. When the impulse spreads to the ventricles along the legs of the bundle of His, they contract. The last bumpy T wave marks the recovery (rest) of the heart before the next cycle.

Not only cardiologists, but also other specialists can decipher diagnostic indicators.

In front of the 5 main teeth on the ECG, you can see a rectangular ledge, you should not be afraid of it, since it is a calibration or control signal. Between the teeth there are horizontally directed sections - segments, for example, S-T (from S to T) or P-Q (from P to Q). To independently make an indicative diagnosis, you will need to remember such a concept as the QRS complex - the combination of the Q, R and S teeth, which registers the work of the ventricles.

The teeth that rise above the isometric line are called positive, and those that are located below them are called negative. Therefore, all 5 teeth alternate one after the other: P (positive), Q (negative), R (positive), S (negative) and T (positive).

Leads

Often you can hear the question from people: why are all the ECG graphs different from each other? The answer is relatively simple. Each of the curved lines on the tape reflects the heart readings obtained from 10-12 colored electrodes, which are installed on the limbs and in the chest area. They read data on the heart impulse, located at different distances from the muscle pump, because the graphics on the thermal tape are often different from each other.

Only an experienced specialist can competently write an ECG conclusion, while the patient has the opportunity to consider general information about his health.

Normal indicators of the cardiogram

Now that it has become clear how to decipher the cardiogram of the heart, one should proceed to the direct diagnosis of normal readings. But before getting acquainted with them, it is necessary to evaluate the ECG recording speed (50 mm / s or 25 mm / s), which, as a rule, is automatically printed on paper tape. Then, starting from the result, you can view the norms for the duration of the teeth and segments that are listed in the table (calculations can be carried out using a ruler or checkered markings on the tape):

Among the most significant provisions of the interpretation of the ECG, the following can be mentioned:

• The S-T and P-Q segments should "merge" with the isometric line without going beyond it.
• The depth of the Q wave cannot exceed ¼ of the height of the most slender tooth - R.
• The exact measurements of the S wave have not been confirmed, but it is known that it sometimes reaches a depth of 18–20 mm.
• The T wave should not be higher than R: its maximum value is ½ of the height of R.

Heart rate control is also important. It is necessary to pick up a ruler and measure the length of the segments enclosed between the vertices of R: the results obtained must coincide with each other. To calculate the heart rate (or heart rate), it is worth counting the total number of small cells between the 3 vertices of R and dividing the digital value by 2. Next, you need to apply one of the 2 formulas:

• 60/X*0.02 (at 50mm/s write speed).
• 60/X*0.04 (at 25mm/s write speed).

If the figure is in the range from 59-60 to 90 beats / min, then the heart rate is normal. An increase in this index implies tachycardia, and a clear decrease implies bradycardia. If for a formed person, a heart rate of more than 95–100 beats / min is a rather dubious sign, then for children under 5–6 years old this is one of the varieties of the norm.

Each of the teeth and intervals indicates a certain period of time for the work of the heart muscle.

What pathologies can be identified when deciphering the data?

Although the ECG is one of the extremely simple studies in terms of structure, there are still no analogues of such a diagnosis of cardiac abnormalities. The most "popular" diseases recognized by ECG can be found by examining both the description of their characteristic indicators and detailed graphic examples.

This ailment is often recorded in adults during the implementation of the ECG, but in children it is extremely rare. Among the most common "catalysts" of the disease are the use of drugs and alcohol, chronic stress, hyperthyroidism, etc. PT is distinguished, first of all, by a frequent heartbeat, the indicators of which range from 138-140 to 240-250 beats / min.

Due to the manifestation of such attacks (or paroxysm), both ventricles of the heart do not have the opportunity to fill with blood in time, which weakens the overall blood flow and slows down the delivery of the next portion of oxygen to all parts of the body, including the brain. Tachycardia is characterized by the presence of a modified QRS complex, a mild T wave, and, most importantly, the absence of a distance between T and P. In other words, the groups of teeth on the electrocardiogram are "glued" to each other.

The disease is one of the "invisible killers" and requires immediate contact with a number of specialists, since if it is extremely neglected, it can lead to the death of a person.

Bradycardia

If the previous anomaly implied the absence of the T-P segment, then bradycardia is its antagonist. This ailment produces precisely a significant lengthening of T-P, indicating a weak conduction of the impulse or its incorrect accompaniment through the heart muscle. In patients with bradycardia, an extremely low heart rate index is observed - less than 40-60 bpm. If in people who prefer regular physical activity, a mild manifestation of the disease is the norm, then in the vast majority of other cases, we can talk about the emergence of an extremely serious disease.

If obvious signs of bradycardia are found, a comprehensive examination should be carried out in the near future.

Ischemia

Ischemia is called a harbinger of myocardial infarction, for this reason, early detection of an anomaly contributes to the relief of a fatal ailment and, as a result, a favorable outcome. It was previously mentioned that the S-T interval should “comfortably lie” on the isoline, however, its omission in the 1st and AVL leads (up to 2.5 mm) signals precisely about IHD. Sometimes coronary heart disease gives out only the T wave. Normally, it should not exceed ½ of the R height, however, in this case it can either “grow” to the older element or fall below the midline. The remaining teeth are not subject to significant changes.

Flutter and atrial fibrillation

Atrial fibrillation is an abnormal condition of the heart, expressed in a disorderly, chaotic manifestation of electrical impulses in the upper pockets of the heart. It is sometimes not possible to make a qualitative surface analysis in such a case. But knowing what you should pay attention to first of all, you can safely decipher the ECG indicators. QRS complexes are not of fundamental importance, since they are often stable, but the gaps between them are key indicators: when they flicker, they look like a series of notches on a hand saw.

Pathologies are clearly distinguishable on the cardiogram

Not so chaotic, large-sized waves between the QRS already indicate atrial flutter, which, unlike flicker, is characterized by a slightly more pronounced heartbeat (up to 400 beats / min). Contractions and excitations of the atria are subject to control to a small extent.

Thickening of the atrial myocardium

Suspicious thickening and stretching of the muscle layer of the myocardium is accompanied by a significant problem with the internal blood flow. At the same time, the atria perform their main function with constant interruptions: the thickened left chamber “pushes” blood into the ventricle with greater force. When trying to read an ECG graph at home, you should focus on the P wave, which reflects the state of the upper heart.

If it is a kind of dome with two bulges, most likely the patient is suffering from the disease in question. Since thickening of the myocardium in the absence of qualified medical intervention for a long time provokes a stroke or heart attack, it is necessary to make an appointment with a cardiologist as soon as possible, providing a detailed description of uncomfortable symptoms, if any.

Extrasystole

It is possible to decipher the ECG with the "first signs" of extrasystole if there is knowledge about the special indicators of a special manifestation of arrhythmia. By carefully examining such a graph, the patient can detect unusual abnormal jumps that vaguely resemble QRS complexes - extrasystoles. They occur in any area of ​​the ECG, they are often followed by a compensatory pause, allowing the heart muscle to “rest” before starting a new cycle of excitations and contractions.

Extrasystole in medical practice is often diagnosed in healthy people. In the vast majority of cases, it does not affect the usual course of life and is not associated with serious illnesses. However, when establishing an arrhythmia, you should play it safe by contacting specialists.

With atrioventricular heart block, an expansion of the gap between the P waves of the same name is observed, in addition, they can occur at the time of analyzing the ECG conclusion much more often than QRS complexes. The registration of such a pattern indicates a low conductivity of the impulse from the upper chambers of the heart to the ventricles.

If the disease progresses, the electrocardiogram changes: now the QRS “drops out” from the general row of P waves in some intervals

Blockade of the legs of the bundle of His

The failure of such an element of the conduction system as the bundle of His should in no case be ignored, since it is located in close proximity to the Myocardium. The pathological focus in advanced cases tends to "transfer" to one of the most important parts of the heart. It is quite possible to decipher the ECG yourself in the presence of an extremely unpleasant disease, you just have to carefully examine the highest tooth on the thermal tape. If it forms not a “slender” letter L, but a deformed M, this means that the bundle of His has been attacked.

The defeat of its left leg, which passes the impulse into the left ventricle, entails the complete disappearance of the S wave. And the place of contact of the two peaks of the split R will be located above the isoline. The cardiographic image of the weakening of the right bundle crus is similar to the previous one, only the junction point of the already marked peaks of the R wave is under the midline. T is negative in both cases.

myocardial infarction

The myocardium is a fragment of the densest and thickest layer of the heart muscle, which in recent years has been subjected to various ailments. The most dangerous among them is necrosis or myocardial infarction. When deciphering electrocardiography, it is quite distinguishable from other types of diseases. If the P wave, which registers the good condition of the 2 atria, is not deformed, then the remaining segments of the ECG have undergone significant changes. So, a pointed Q wave can “pierce” the isoline plane, and T can be transformed into a negative tooth.

The most telling sign of a heart attack is an unnatural R-T elevation. There is a mnemonic rule that allows you to remember its exact appearance. If, when examining this area, one can imagine the left, ascending side of R in the form of a rack tilted to the right, on which a flag flies, then we are really talking about myocardial necrosis.

The disease is diagnosed both in the acute phase and after the attack subsides.

ventricular fibrillation

Otherwise, an extremely serious illness is called atrial fibrillation. A distinctive feature of this pathological phenomenon is considered to be the destructive activity of the conductive bundles and nodes, indicating an uncontrolled contraction of all 4 chambers of the muscle pump. Reading the results of an ECG and recognizing ventricular fibrillation is not at all difficult: on a checkered tape, it appears as a series of chaotic waves and hollows, the parameters of which cannot be correlated with classical indicators. In none of the segments can you see at least one familiar complex.

If a patient with atrial fibrillation is not provided with premature medical care, he will soon die.

WPW syndrome

When, in the complex of classical pathways for conducting an electrical impulse, an abnormal Kent bundle is unexpectedly formed, located in the “comfortable cradle” of the left or right atrium, we can confidently speak of such a pathology as WPW syndrome. As soon as the impulses begin to move along the unnatural cardiac highway, the rhythm of the muscle goes astray. The "correct" conducting fibers cannot fully supply the atria with blood, because the impulses preferred a shorter path to complete the functional cycle.

The ECG in SVC syndrome is distinguished by the appearance of a microwave at the left foot of the R wave, a slight widening of the QRS complex, and, of course, a significant reduction in the P-Q interval. Since the decoding of the cardiogram of a heart that has undergone WPW is not always effective, HM comes to the aid of medical personnel - the Holter method for diagnosing an ailment. It involves wearing around the clock on the body of a compact device with sensors attached to the skin.

Long-term monitoring provides a better result with a reliable diagnosis. In order to “catch” the anomaly localized in the heart in a timely manner, it is recommended to visit the ECG room at least once a year. If regular medical monitoring of the treatment of cardiovascular disease is necessary, more frequent measurements of cardiac activity may be required.

Any electrocardiogram displays the work of the heart (its electrical potential during contractions and relaxations) in 12 curves recorded in 12 leads. These curves differ from each other, as they show the passage of an electrical impulse through different parts of the heart, for example, the first is the anterior surface of the heart, the third is the back. To record an ECG in 12 leads, special electrodes are attached to the patient's body in specific places and in a certain sequence.

How to decipher the cardiogram of the heart: general principles

The main elements of the electrocardiographic curve are:

ECG analysis

Having received an electrocardiogram in his hands, the doctor begins to evaluate it in the following sequence:

1. It determines whether the heart beats rhythmically, that is, whether the rhythm is correct. To do this, he measures the intervals between the R waves, they should be the same everywhere, if not, this is already the wrong rhythm.
2. Calculates the rate at which the heart beats (HR). This is easy to do, knowing the ECG recording speed and counting the number of millimeter cells between adjacent R waves. Normally, the heart rate should not go beyond 60-90 beats. in a minute.
3. According to specific features (mainly by the P wave), it determines the source of excitation in the heart. Normally, this is the sinus node, that is, in a healthy person, sinus rhythm is considered normal. Atrial, atrioventricular and ventricular rhythms indicate pathology.
4. Assesses the conduction of the heart by the duration of the teeth and segments. For each of them there are indicators of the norm.
5. Determines the electrical axis of the heart (EOS). For very thin people, a more vertical position of the EOS is characteristic, for full people it is more horizontal. With pathology, the axis shifts sharply to the right or left.
6. Analyzes teeth, segments and intervals in detail. The doctor writes down their duration on the cardiogram by hand in seconds (this is an incomprehensible set of Latin letters and numbers on the ECG). Modern electrocardiographs automatically analyze these indicators and immediately provide measurement results, which simplifies the work of the doctor.
7. Gives a conclusion. It necessarily indicates the correctness of the rhythm, the source of excitation, heart rate, characterizes the EOS, and also highlights specific pathological syndromes (rhythm disturbance, conduction disturbance, the presence of overload of individual parts of the heart and myocardial damage), if any.

Examples of electrocardiographic findings

In a healthy person, the ECG conclusion may look like this: sinus rhythm with a heart rate of 70 beats. in min. EOS in the normal position, no pathological changes were detected.

Also, for some people, sinus tachycardia (acceleration of heart rate) or bradycardia (slow heart rate) can be considered a normal option. In elderly people, quite often, the conclusion may indicate the presence of moderate diffuse or metabolic changes in the myocardium. These conditions are not critical and after receiving appropriate treatment and correction of the patient's nutrition, they mostly always disappear.

In addition, in conclusion, we can talk about a non-specific change in the ST-T interval. This means that the changes are not indicative and it is impossible to determine their cause only by the ECG. Another fairly common condition that can be diagnosed by a cardiogram is a violation of repolarization processes, that is, a violation of the recovery of the ventricular myocardium after excitation. This change can be caused by both severe heart disease and chronic infections, hormonal imbalances and other causes that the doctor will subsequently look for.

Prognostically unfavorable conclusions are considered, in which there is data on the presence of myocardial ischemia, hypertrophy of the heart, rhythm and conduction disturbances.

Deciphering the ECG in children

The whole principle of deciphering cardiograms is the same as in adults, but due to the physiological and anatomical features of the child's heart, there are differences in the interpretation of normal indicators. This applies primarily to heart rate, since up to 5 years in children it can exceed 100 beats. in a minute.

Also, sinus or respiratory arrhythmia (increased heart rate on inspiration and decrease on expiration) can be recorded in babies without any pathology. In addition, the characteristics of some teeth and intervals differ from those of adults. For example, a child may have an incomplete blockade of part of the conduction system of the heart - the right leg of the bundle of His. All these features are taken into account by pediatric cardiologists when they make a conclusion on the ECG.

Features of the ECG during pregnancy

The body of a pregnant woman goes through various processes of adaptation to a new situation. Certain changes also occur with the cardiovascular system, so the ECG of future mothers may differ slightly from the results of a study of the heart of a healthy adult. First of all, in the later stages there is a slight horizontal deviation of the EOS, caused by a change in the relative placement of the internal organs and the growing uterus.

In addition, expectant mothers may have a slight sinus tachycardia and signs of overload of individual parts of the heart. These changes are associated with an increase in blood volume in the body and usually disappear after childbirth. However, their discovery cannot be left without detailed consideration and a more in-depth examination of the woman.

Deciphering the ECG, the norm of indicators

Deciphering the ECG is the business of a knowledgeable doctor. With this method of functional diagnostics, the following is evaluated:

• heart rhythm - the state of the generators of electrical impulses and the state of the heart system that conducts these impulses
• the state of the heart muscle itself (myocardium). the presence or absence of its inflammation, damage, thickening, oxygen starvation, electrolyte imbalance

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

To reduce the intensity of passions, we immediately warn readers that with no serious diagnosis (myocardial infarction, acute rhythm disturbances), the functional diagnostician of the patient will not let the patient out of the office, but at least send him for a consultation with a specialist colleague right there. About the rest of the "secrets of the Open" in this article. In all unclear cases of pathological changes on the ECG, ECG control, daily monitoring (Holter), ECHO cardioscopy (ultrasound of the heart) and stress tests (treadmill, bicycle ergometry) are prescribed.

Numbers and Latin letters in ECG decoding

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

P - (0.1s) height 0.25-2.5 mm describes atrial contractions. Can talk about their hypertrophy.

QRS - (0.06-0.1s) - ventricular complex

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

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

The decoding of the ECG in children is shown in Fig. 3

Options for describing the heart rate

Sinus rhythm

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

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

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

Sinus tachycardia

Heart rate more than 90 per minute - is divided into physiological and pathological. In healthy people, sinus tachycardia is accompanied by physical and emotional stress, drinking coffee, sometimes strong tea or alcohol (especially energy drinks). It is short-lived and after an episode of tachycardia, the heart rate returns to normal in a short period of time after the cessation of the load. With pathological tachycardia, palpitations disturb the patient at rest. Its causes are temperature rises, infections, blood loss, dehydration, thyrotoxicosis, anemia, cardiomyopathy. Treat the underlying disease. Sinus tachycardia is stopped only with a heart attack or acute coronary syndrome.

Extrasystole

These are rhythm disturbances, in which foci outside the sinus rhythm give extraordinary heart contractions, after which there is a pause doubled in length, called a compensatory one. In general, heartbeats are perceived by the patient as uneven, rapid or slow, sometimes chaotic. Most of all, failures in the heart rhythm are disturbing. There may be discomfort in the chest in the form of jolts, tingling, feelings of fear and emptiness in the abdomen.

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

• Single extrasystoles are most often rare (less than 5 per hour). They are usually functional and do not interfere with the normal blood supply.
• Paired extrasystoles of two accompany a certain number of normal contractions. Such a rhythm disturbance often indicates pathology and requires additional examination (Holter monitoring).
• Allorhythmias are more complex types of extrasystoles. If every second contraction is an extrasystole, it is bigymenia, if every third is trigynemia, and every fourth is quadrihymenia.

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

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

The higher the class, the more serious the violations, although today even grades 3 and 4 do not always require medical treatment. In general, if there are less than 200 ventricular extrasystoles per day, they should be classified as functional and not worry about them. With more frequent, ECHO of the COP is indicated, sometimes - MRI of the heart. They do not treat extrasystole, but the disease that leads to it.

Paroxysmal tachycardia

In general, paroxysm is an attack. Paroxysmal acceleration of the rhythm can last from several minutes to several days. In this case, the intervals between heartbeats will be the same, and the rhythm will increase over 100 per minute (on average from 120 to 250). There are supraventricular and ventricular forms of tachycardia. The basis of this pathology is the abnormal circulation of an electrical impulse in the conduction system of the heart. Such a pathology is subject to treatment. From home remedies to eliminate an attack:

• breath holding
• increased forced cough
• face immersion in cold water

WPW syndrome

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

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

CLC - Syndrome (Clerk-Levy-Christesco)

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

Atrial fibrillation

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

Atrial fibrillation

Atrial fibrillation

When the heart flickers, it contracts completely irregularly (intervals between contractions of very different durations). This is due to the fact that the rhythm is not set by the sinus node, but by other atrial cells.

It turns out a frequency of 350 to 700 beats per minute. There is simply no full-fledged atrial contraction; the contracting muscle fibers do not provide effective filling of the ventricles with blood.

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

An attack of atrial fibrillation is difficult to miss.

• It usually starts with a strong heartbeat.
• It develops as a series of absolutely non-rhythmic heartbeats with a high or normal frequency.
• The condition is accompanied by weakness, sweating, dizziness.
• The fear of death is very pronounced.
• There may be shortness of breath, general arousal.
• Sometimes there is a loss of consciousness.
• The attack ends with the normalization of the rhythm and the urge to urinate, in which a large amount of urine leaves.

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

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

Examples of recordings on ECG films:

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

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

atrial flutter

These are frequent (more than 200 per minute) regular atrial contractions and the same regular, but more rare ventricular contractions. In general, flutter is more common in the acute form and is better tolerated than flicker, since circulatory disorders are less pronounced. Trembling develops when:

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

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

Conduction disorders

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

Sinoatrial blockade

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

Atrioventricular block (AV block)

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

• At the first delay allows each atrial contraction to maintain an adequate number of ventricular contractions.
• The second degree leaves part of the atrial contractions without ventricular contractions. It is described in terms of PQ prolongation and ventricular beat prolapse as Mobitz 1, 2, or 3.
• The third degree is also called a complete transverse block. The atria and ventricles begin to contract without interrelation.

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

Conduction disturbance within the ventricles

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

In addition to the place of origin, a complete or incomplete blockade is distinguished, as well as permanent and non-permanent. The causes of intraventricular blockades are similar to other conduction disorders (IHD, myo- and endocarditis, cardiomyopathies, heart defects, arterial hypertension, fibrosis, heart tumors). Also, the intake of antiarthmic drugs, an increase in potassium in the blood plasma, acidosis, and oxygen starvation also affect.

• The most common is the blockade of the anteroposterior branch of the left leg of the bundle of His (BPVLNPG).
• In second place is the blockade of the right leg (RBNB). This blockade is usually not accompanied by heart disease.
• Blockade of the left leg of the His bundle is more typical for myocardial lesions. At the same time, complete blockade (PBBBB) is worse than incomplete blockade (NBLBBB). It sometimes has to be distinguished from the WPW syndrome.
• The blockade of the posterior inferior branch of the left leg of the bundle of His can be in persons with a narrow and elongated or deformed chest. Of the pathological conditions, it is more characteristic of right ventricular overload (with pulmonary embolism or heart defects).

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

• Bailey's syndrome - two-beam blockade (of the right leg and posterior branch of the left leg of the bundle of His).

Myocardial hypertrophy

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

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

Changes in myocardial contractility and nutrition

Syndrome of early repolarization of the ventricles

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

Moderate or severe diffuse changes in the myocardium

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

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

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

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

Developed heart attack

It is usually described as:

• by stages. acute (up to 3 days), acute (up to 3 weeks), subacute (up to 3 months), cicatricial (lifelong after a heart attack)
• by volume. transmural (large focal), subendocardial (small focal)
• according to the location of the infarction. are anterior and anterior-septal, basal, lateral, inferior (posterior diaphragmatic), circular apical, posterior basal and right ventricular.

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

How to decipher the ECG of the heart?

An electrocardiographic study is the simplest, but very informative method for studying the work of a patient's heart. The result of this procedure is an ECG. Incomprehensible lines on a piece of paper contain a lot of information about the state and functioning of the main organ in the human body. Deciphering ECG indicators is quite simple. The main thing is to know some of the secrets and features of this procedure, as well as the norms of all indicators.

Exactly 12 curves are recorded on the ECG. Each of them tells about the work of each specific part of the heart. So, the first curve is the anterior surface of the heart muscle, and the third line is its posterior surface. To record the cardiogram of all 12 leads, electrodes are attached to the patient's body. The specialist does this sequentially, installing them in specific places.

Decryption principles

Each curve on the cardiogram graph has its own elements:

• Teeth, which are bulges directed down or up. All of them are denoted by Latin capital letters. "P" shows the work of the heart atria. "T" is the restorative capacity of the myocardium.
• Segments are the distance between several ascending or descending teeth in the neighborhood. Doctors are especially interested in indicators of such segments as ST, as well as PQ.
• An interval is a gap that includes both a segment and a tooth.

Each specific ECG element shows a certain process that occurs directly in the heart. According to their width, height and other parameters, the doctor has the ability to correctly decipher the data received.

How are the results analyzed?

As soon as the specialist receives the electrocardiogram in his hands, its decoding begins. This is done in a certain strict sequence:

1. The correct rhythm is determined by the intervals between the "R"-teeth. They must be equal. Otherwise, it can be concluded that the heart rhythm is incorrect.
2. With the help of an ECG, you can determine the heart rate. To do this, you need to know the speed at which the indicators were recorded. Additionally, you will also need to count the number of cells between the two R waves. The norm is from 60 to 90 beats per minute.
3. The source of excitation in the heart muscle is determined by a number of specific features. This will be told, among other things, by the evaluation of the parameters of the “P” wave. The norm implies that the source is the sinus node. Therefore, a healthy person always has a sinus rhythm. If there is a ventricular, atrial or any other rhythm, then this indicates the presence of pathology.
4. The specialist evaluates the conduction of the heart. This happens according to the duration of each segment and tooth.
5. The electrical axis of the heart, if it shifts to the left or right sharply enough, may also indicate problems with the cardiovascular system.
6. Each tooth, interval and segment is analyzed individually and in detail. Modern ECG devices immediately automatically issue indicators of all measurements. This greatly simplifies the work of the doctor.
7. Finally, the specialist makes a conclusion. It indicates the decoding of the cardiogram. If any pathological syndromes were found, they must be indicated there.

Normal indicators of adults

The norm of all indicators of the cardiogram is determined by analyzing the position of the teeth. But the rhythm of the heart is always measured by the distance between the highest teeth "R" - "R". Normally they should be equal. The maximum difference can be no more than 10%. Otherwise, it will no longer be the norm, which should be within 60-80 pulsations per minute. If sinus rhythm is more frequent, then the patient has tachycardia. On the contrary, a slow sinus rhythm indicates a disease called bradycardia.

The P-QRS-T intervals will tell you about the passage of the impulse directly through all the cardiac departments. The norm is an indicator from 120 to 200 ms. On the graph, it looks like 3-5 squares.

By measuring the width from the Q wave to the S wave, one can get an idea of ​​the excitation of the ventricles of the heart. If this is the norm, then the width will be 60-100 ms.

The duration of ventricular contraction can be determined by measuring the Q-T interval. The norm is 390-450 ms. If it is somewhat longer, a diagnosis can be made: rheumatism, ischemia, atherosclerosis. If the interval is shortened, we can talk about hypercalcemia.

What do teeth mean?

Without fail, when deciphering the ECG, it is necessary to monitor the height of all teeth. It can indicate the presence of serious pathologies of the heart:

• The Q wave is an indicator of excitation of the left cardiac septum. The norm is a quarter of the length of the R wave. If it is exceeded, there is a possibility of necrotic pathology of the myocardium;
• The S wave is an indicator of the excitation of those partitions that are in the basal layers of the ventricles. The norm in this case is 20 mm in height. If there are deviations, then this indicates coronary disease.
• The R wave in the ECG tells about the activity of the walls of all the ventricles of the heart. It is fixed in all ECG curves. If there is no activity somewhere, then it makes sense to suspect ventricular hypertrophy.
• The T wave appears in the I and II lines, as directed upwards. But in the VR curve it is always negative. When the T wave is too high and sharp on the ECG, the doctor suspects hyperkalemia. If it is long and flat, then there is a possibility of developing hypokalemia.

Normal pediatric electrocardiogram readings

In childhood, the norm of ECG indicators may differ slightly from the characteristics of an adult:

1. The heart rate of babies under 3 years old is about 110 pulsations per minute, and at the age of 3-5 years - 100 beats. This indicator in adolescents is already lower - 60-90 pulsations.
2. The norm of QRS readings is 0.6-0.1 s.
3. The P wave should normally not be higher than 0.1 s.
4. The electrical axis of the heart in children should remain unchanged.
5. The rhythm is only sinus.
6. On the ECG, the Q-T interval e can exceed 0.4 s, and P-Q should be 0.2 s.

Sinus heart rate in the decoding of the cardiogram is expressed as a function of heart rate on respiration. This means that the heart muscle is contracting normally. In this case, the pulsation is 60-80 beats per minute.

Why are the scores different?

Often, patients are faced with a situation where their ECG readings are different. What is it connected with? To get the most accurate results, there are many factors to consider:

1. Distortions in recording an ECG may be due to technical problems. For example, with incorrect gluing of results. And many Roman numerals look the same both upside down and upside down. It happens that the graph is cut incorrectly or the first or last tooth is lost.
2. Preliminary preparation for the procedure is important. On the day of the ECG, you should not have a hearty breakfast, it is even advisable to completely refuse it. You will have to stop drinking liquids, including coffee and tea. After all, they stimulate the heart rate. As a result, the results are skewed. It is best to take a shower beforehand, but you do not need to apply any body products. Finally, during the procedure you need to relax as much as possible.
3. The incorrect position of the electrodes cannot be ruled out.

It is best to check your heart on an electrocardiograph. He will help to carry out the procedure as accurately and accurately as possible. And in order to confirm the diagnosis indicated by the results of the ECG, the doctor will always prescribe additional studies.

Cardiovascular disease is the most common cause of death in post-industrial societies. Timely diagnosis and therapy of the organs of the cardiovascular system helps to reduce the risk of developing heart pathologies among the population.

An electrocardiogram (ECG) is one of the simplest and most informative methods for studying cardiac activity. The ECG records the electrical activity of the heart muscle and displays the information in the form of waves on a paper tape.

ECG results are used in cardiology to diagnose various diseases. Self-heart is not recommended, it is better to consult a specialist. However, to get a general idea, it is worth knowing what the cardiogram shows.

Indications for an ECG

• severe chest pain;
• constant fainting;
• dyspnea;
• intolerance to physical activity;
• dizziness;
• murmurs in the heart.

With a planned examination, the ECG is a mandatory diagnostic method. There may be other indications, which are determined by the attending physician. If you have any other alarming symptoms, consult a doctor immediately to identify their cause.

How to decipher the cardiogram of the heart?

A strict ECG decoding plan consists of analyzing the resulting graph. In practice, only the total vector of the QRS complex is used. The work of the heart muscle is presented as a continuous line with marks and alphanumeric designations. Any person can decipher the ECG with some preparation, but only a doctor can make the correct diagnosis. ECG analysis requires knowledge of algebra, geometry and understanding of letter symbols.

ECG indicators to which you need to pay attention when deciphering the results:

• intervals;
• segments;
• teeth.

There are strict indicators of the norm on the ECG, and any deviation is already a sign of abnormalities in the functioning of the heart muscle. Pathology can be excluded only by a qualified specialist - a cardiologist.

ECG interpretation in adults - the norm in the table

ECG analysis

ECG records cardiac activity in twelve leads: 6 limb leads (aVR, aVL, aVF, I, II, III) and six chest leads (V1-V6). The P wave represents the process of atrial excitation and relaxation. The Q,S waves show the phase of depolarization of the interventricular septum. R is a wave indicating depolarization of the lower chambers of the heart, and a T wave is relaxation of the myocardium.

Electrocardiogram analysis

The QRS complex shows the time of depolarization of the ventricles. The time it takes for an electrical impulse to travel from the SA node to the AV node is measured by the PR interval.

Computers built into most ECG devices are capable of measuring the time it takes for an electrical impulse to travel from the SA node to the ventricles. These measurements can help your doctor evaluate your heart rate and j,yfhe;bnm some types of heart block.

Computer programs can also interpret ECG results. And as artificial intelligence and programming improves, they are often more accurate. However, the interpretation of the ECG has a lot of subtleties, so the human factor is still an important part of the assessment.

In the electrocardiogram, there may be deviations from the norm that do not affect the quality of life of the patient. However, there are standards for normal cardiac performance that are accepted by the international cardiology community.

Based on these standards, a normal electrocardiogram in a healthy person is as follows:

• RR interval - 0.6-1.2 seconds;
• P-wave - 80 milliseconds;
• PR interval - 120-200 milliseconds;
• segment PR - 50-120 milliseconds;
• QRS complex - 80-100 milliseconds;
• J-prong: absent;
• ST segment - 80-120 milliseconds;
• T-prong - 160 milliseconds;
• ST interval - 320 milliseconds;
• the QT interval is 420 milliseconds or less if the heart rate is sixty beats per minute.
• ind. juice – 17.3.

Normal ECG

Pathological ECG parameters

The ECG in normal and pathological conditions is significantly different. Therefore, it is necessary to carefully approach the decoding of the cardiogram of the heart.

QRS complex

Any abnormality in the electrical system of the heart causes a lengthening of the QRS complex. The ventricles have more muscle mass than the atria, so the QRS complex is significantly longer than the P wave. The duration, amplitude, and morphology of the QRS complex are useful in detecting cardiac arrhythmias, conduction abnormalities, ventricular hypertrophy, myocardial infarction, electrolyte abnormalities, and other disease states.

Q, R, T, P, U teeth

Pathological Q waves occur when an electrical signal travels through damaged heart muscle. They are considered markers of a previous myocardial infarction.

R-wave depression is usually also associated with myocardial infarction, but it can also be caused by left bundle branch block, WPW syndrome, or hypertrophy of the lower chambers of the heart muscle.

Table of ECG indicators is normal

T-wave inversion is always considered abnormal on the ECG tape. Such a wave may be a sign of coronary ischemia, Wellens' syndrome, hypertrophy of the lower cardiac chambers, or a CNS disorder.

An enlarged P wave may indicate hypokalemia and right atrial hypertrophy. Conversely, a reduced P wave may indicate hyperkalemia.

U-waves are most commonly seen with hypokalemia but may also be present with hypercalcemia, thyrotoxicosis, or epinephrine, class 1A and class 3 antiarrhythmic drugs. They are not uncommon in congenital long QT syndrome and intracranial hemorrhage.

An inverted U-wave may indicate pathological changes in the myocardium. Another U-wave can sometimes be seen on the ECG in athletes.

QT, ST, PR intervals

QTc prolongation causes premature action potentials during the late phases of depolarization. This increases the risk of developing ventricular arrhythmias or fatal ventricular fibrillation. Higher rates of QTc elongation are observed in women, older patients, hypertensive patients and in people of small stature.

The most common causes of QT prolongation are hypertension and certain medications. The calculation of the duration of the interval is carried out according to the Bazett formula. With this sign, the interpretation of the electrocardiogram should be performed taking into account the history of the disease. Such a measure is necessary to exclude hereditary influence.

ST interval depression may indicate coronary artery ischemia, transmural myocardial infarction, or hypokalemia.

Characteristics of all indicators of an electrocardiographic study

A prolonged PR interval (greater than 200 ms) may indicate first-degree heart block. Lengthening may be associated with hypokalemia, acute rheumatic fever, or Lyme disease. A short PR interval (less than 120 ms) may be associated with Wolff-Parkinson-White syndrome or Lown-Ganong-Levine syndrome. PR segment depression may indicate atrial injury or pericarditis.

Examples of heart rhythm description and ECG interpretation

Normal sinus rhythm

Sinus rhythm is any heart rhythm in which the excitation of the heart muscle starts from the sinus node. It is characterized by correctly oriented P waves on the ECG. By convention, the term "normal sinus rhythm" includes not only normal P waves, but all other ECG measurements.

ECG norm and interpretation of all indicators

ECG norm in adults:

1. heart rate from 55 to 90 beats per minute;
2. regular rhythm;
3. normal PR interval, QT and QRS complex;
4. The QRS complex is positive in almost all leads (I, II, AVF and V3-V6) and negative in aVR.

Sinus bradycardia

A heart rate less than 55 in sinus rhythm is called bradycardia. ECG decoding in adults should take into account all parameters: sports, smoking, medical history. Because in some cases, bradycardia is a variant of the norm, especially in athletes.

Pathological bradycardia occurs with weak sinus node syndrome and is recorded on the ECG at any time of the day. This condition is accompanied by constant fainting, pallor and hyperhidrosis. In extreme cases, with malignant bradycardia, pacemakers are prescribed.

Sinus bradycardia

Signs of pathological bradycardia:

1. heart rate less than 55 beats per minute;
2. sinus rhythm;
3. P waves are vertical, consistent, and normal in morphology and duration;
4. PR interval from 0.12 to 0.20 seconds;

Sinus tachycardia

The correct rhythm with a high heart rate (above 100 beats per minute) is called sinus tachycardia. Please note that the normal heart rate varies with age, for example, in infants, the heart rate can reach 150 beats per minute, which is considered normal.

Advice! At home, with severe tachycardia, a strong cough or pressure on the eyeballs can help. These actions stimulate the vagus nerve, which activates the parasympathetic nervous system, causing the heart to beat more slowly.

Sinus tachycardia

Signs of pathological tachycardia:

1. Heart rate above 100 beats per minute
2. sinus rhythm;
3. P waves are vertical, consistent and normal in morphology;
4. the PR interval fluctuates between 0.12-0.20 seconds and decreases with increasing heart rate;
5. QRS complex less than 0.12 seconds.

Atrial fibrillation

Atrial fibrillation is an abnormal heart rhythm characterized by rapid and irregular atrial contraction. Most episodes are asymptomatic. Sometimes an attack is accompanied by the following symptoms: tachycardia, fainting, dizziness, shortness of breath, or chest pain. The disease is associated with an increased risk of heart failure, dementia, and stroke.

Atrial fibrillation

Signs of atrial fibrillation:

1. Heart rate unchanged or accelerated;
2. P waves absent;
3. electrical activity is chaotic;
4. RR intervals are irregular;
5. QRS complex less than 0.12 seconds (in rare cases, the QRS complex is lengthened).

Important! Despite the above explanations with the interpretation of the data, the conclusion on the ECG should be made only by a qualified specialist - a cardiologist or a general practitioner. Deciphering the electrocardiogram and differential diagnosis requires higher medical education.

How to "read" myocardial infarction on an ECG?

For students beginning the study of cardiology, the question often arises, how to learn how to read a cardiogram correctly and identify myocardial infarction (MI)? You can “read” a heart attack on a paper tape by several signs:

• elevation of the ST segment;
• peaked T wave;
• deep Q wave or its absence.

In the analysis of the results of electrocardiography, these indicators are first of all identified, and then dealt with others. Sometimes the earliest sign of an acute myocardial infarction is only a peaked T-wave. In practice, this is quite rare, because it appears only 3-28 minutes after the onset of a heart attack.

Electrocardiography is considered the simplest method for determining the quality of the heart, both in normal and pathological conditions. The essence of this method is to capture and fix the electrical impulses of the heart that occur during its work.

But in order to determine the degree of violation, it is necessary to decipher the ECG of the heart, since the fixation of these impulses is performed using a specific graphic image for a certain time.

Indications for an ECG:

1. For preventive purposes;
2. Directed determination of the frequency of contractions of the heart muscle and the rhythm of the work of the organ;
3. Definition of acute and chronic heart failure;
4. Identification of various conduction disorders inside the heart;
5. In order to determine the physical condition of the heart;
6. Diagnostics ;
7. Obtaining information about pathologies that occur outside the heart (for example, complete or partial).

Principles of ECG decoding

Three main indicators are schematically shown on the electrocardiogram:

1. Teeth - bulges with an acute angle, directed up or down and are designated P, Q, R, S, T;
2. Segments - are the distance between adjacent teeth;
3. An interval is a gap that includes both a tooth and a segment.

Thanks to the above indicators, the cardiologist determines the level of contraction and recovery of the heart muscle. In addition to these indicators, during the electrocardiogram, the electrical axis of the heart can also be determined, which indicates the approximate location of the organ in the chest cavity. The latter depends on the constitution of the human body and chronic pathology. The electrical axis of the heart can be: normal, vertical and horizontal.

Key indicators of ECG decoding

When deciphered, the indicators of the norm will be as follows:

1. The distance between the R and R waves should be even throughout the cardiogram;
2. The intervals between PQRST should be between 120 and 200 m/s, graphically this is determined by 2-3 squares. This is an indicator of the passage of the impulse through all cardiac departments from the atria to the ventricles;
3. The interval between Q and S indicates the passage of the impulse through the ventricles (60-100 m/s);
4. The duration of ventricular contractility is determined using Q and T, normally 400-450 m/s;

At the slightest shift from these parameters, one can judge the beginning or development of a pathological process in the heart muscle. Such parameters are especially pronounced in rheumatism.

It should also be noted that in some cases, the ECG decoding norms may vary slightly due to the presence of some disorders that are considered normal, since their presence does not affect the development of heart failure (for example, respiratory arrhythmia). It is important to note that for ECG decoding in adults, the norm can be presented in different tables describing the speed of passage between the elements of the cardiogram.

Ecg decoding in adults is the norm in the table

Ecg decoding norm table

Such tables are an official document for determining possible pathological changes in the heart muscle.

Video: ECG interpretation