Surely many times in your life you have encountered a situation where you need to decipher the “film”: on an exam on the propaedeutics of internal diseases, studying a medical history (and not necessarily at the department of therapy or cardiology) or even advising your mother’s friend who came to you with the words "you're a doctor." If in all these situations you thought: “It seems to have taught electrocardiography at the 2-3 courses of a medical university, but when I take an electrocardiogram in my hands, I understand very little. You need to do something with this, ”then this article is for you. If you are already well versed in electrocardiography, then in any case, the links to various sources mentioned in this article may be useful to you.
Where to start studying ECG?
To understand the ECG, first of all, basic knowledge of physiology is needed. If you are a 1-2 year student at a medical university (or just want to repeat physiology), ECG physiology is best and most understandable in the books “Fundamentals of Medical Physiology” by N. N. Alipov and “Medical Physiology” by Arthur Guyton and John Hall. If you are a student of 3 or more senior courses and are already familiar with the basics of ECG physiology, then most likely it doesn’t make much sense to return to an in-depth study of physiology and for you an abstract of electrophysiology in the initial chapters of books on ECG will suffice, which will be given below .
The main thing that needs to be understood from physiology is what leads are, and most importantly, how the graphical image of the ECG is formed, because, in fact, the ECG is a projection of the integral vector of electrical excitation on the lead. Knowing this, it will already be much easier to understand how the teeth and intervals are formed on the electrocardiogram.
ECG analysis and interpretation
The main thing that is required from the clinician is the ability to analyze any changes in the electrocardiogram and give a clinical interpretation of these changes.
In fact, the most common difficulty that physicians encounter when decoding an ECG is the lack of at least some kind of circuit in the head (even the basic one, without any subtleties), and this creates fear and uncertainty when looking at the ECG. After all, how can one be sure of a conclusion if you don’t know what you needed to analyze at all? So, the first key to your success in decoding the ECG is the presence of a well-developed circuit in your head. Even if the simplest, perhaps, some points you will periodically change places, but the scheme should be.
What scheme specifically to choose? There is no exact answer. All schemes were invented for one purpose - so that you do not forget to analyze all the main points on the electrocardiogram. In fact, they are similar to each other, so for starters, remember at least one, and with practice, if necessary, you can adjust this scheme for yourself. One of the simple but useful schemes that we can recommend to you is an ECG analysis scheme from the book of V.V. Murashko, A.V. Strutinsky:
ECG analysis chart
I. Heart rate and conduction analysis:
1. Assessment of the regularity of heart contractions,
2. Heart rate assessment,
3. Determination of the source of rhythm,
4. Conductivity assessment (duration P, PQ, QRS, QT),
II. Definition of EOS,
III. Analysis of the atrial P wave,
IV. QRS ventricular complex analysis,
V. ST segment,
VI. T wave,
VII. Prongs U.
Despite the fact that the circuit is simple, there is almost everything that needs to be analyzed on an ECG: rhythm and conductivity, the electrical axis of the heart, and then an analysis of the main teeth, segments and intervals in order.
After analyzing the changes on the ECG, it is necessary to produce their clinical interpretation, which, of course, can be even more difficult than the analysis itself, however, for the most frequent and important situations in medicine, basic knowledge is enough to make a conclusion. For interpretation, not only knowledge is important, but also the experience of decoding the ECG. The more ECG you see, the better you will be guided by the clinical significance of the changes you have identified.
What books to start with ECG?
There is no exact answer. Rather, it is a matter of taste. In our opinion, for beginners in the ECG, the best option would be a series of books on ECG by John Hampton. The series consists of three books:
The first is “Fundamentals of ECG.” A very simple, small but useful book. You can read it literally in a few evenings. Why do we consider this manual the most successful for a beginner? It's all about its simplicity. As mentioned above, the most common problem for a beginner is the lack of even the simplest scheme in his head, as well as insecurity when analyzing an ECG. This book will allow you to overcome this "threshold of uncertainty", look at the ECG and know what to look for on it. And this is a very important step, laying the foundation for further study of ECG.
The second is “Atlas of ECG. 150 clinical situations ”is a logical continuation of the first book. After you learn the basics of ECG analysis, you need practice, practice, and practice again. Of course, this atlas is only one of countless other atlases on the ECG (where to look for others, it will be said below), and for practice you can use any other atlas, website, blog or public.
The third - "ECG in the practice of a doctor." Here, individual questions of the clinical interpretation of ECG are already considered in more depth. It is also worth noting that all books are interconnected by text and one part refers to another, which is quite useful.
Another good option to start studying ECG is the well-known book by V. V. Murashko, A. V. Strutinsky “ECG”, which remains a bible for many students of medical universities. Nevertheless, we put this book in second place for beginners, as some of the domestic approaches described in it are already outdated. But, of course, to date, this manual remains one of the best options for beginners to study ECG.
Each needs its own approach, and therefore, of course, you can choose other books for both the beginning and further study of the ECG. The purpose of this article is not to describe absolutely all books and sources on ECG, we offer, in our opinion, the most optimal options for beginners. Links to articles discussing many other ECG books will be provided below.
Further study of ECG
After you have learned the basics of the ECG and learned to look confidently at the electrocardiogram, knowing that you should analyze it and how to interpret the main changes you found, you need 2 things - first of all practice, as well as an in-depth study of individual topics on the ECG.
The main thing that you need to understand about ECG practice is that it should be regular. ECG analysis and interpretation is a skill that needs to be trained. At first it can be difficult, many small questions will arise about various details. This is normal, the main thing is to try to understand incomprehensible questions, often look in books and ECG guides.
After some time viewing the ECG shek you will feel something like a “point of no return”, when you can look at the ECG in a comprehensive manner, confidently excluding or confirming the main pathologies. However, there will still be complex, controversial cases that will force you to read more in-depth ECG books and articles and ask colleagues for advice.
Where to find an ECG for regular practice?
There are various sources: atlases, publics, sites, videos, programs on smartphones.
Subscribe to public VKontakte:
- MEDIC: ECG. In this group, an ECG is laid out every day in the morning with answer options in the form of a test, and in the evening an answer is given with an analysis of the main changes in the ECG. You can also find various sources and articles on ECG.
- ECG tests. Another great public with ECG tests every day. His admin also translated many different ECG books from English, created several ECG reference programs for computers and phones, all of which can be found in the group.
1. https://lifeinthefastlane.com/ecg-library/ - on this site you can find many different ECG examples. It is also one of the best sites that can be used as a reference when you do not understand something, and even to some extent as a study guide.
4. https://www.skillstat.com/tools/ecg-simulator - online ECG simulator (see picture) Try your hand at determining the rhythm on the monitor for speed! You can also download the ECG simulator on your computer: https://cloud.mail.ru/public/6aLN/9xaABKDea
More useful ECG public sites and sites can be found in this article on MEDIC: ECG - https://vk.com/@medic_ecg-ssylki-na-resursy-po-ekg
ECG atlases, applications and videos
1. Clinical electrocardiography - Franklin Zimmerman. 200 electrocardiograms with excellent analysis and explanations.
2. Podrids Real-World ECGs. One of the most famous atlases on the interpretation of ECG (6 volumes).
Books for a more in-depth study of ECG:
1. Practical electrocardiography by Marriott - one of the most comprehensive ECG guides,
2. Guide to electrocardiography - Orlov V.N.
You will find even more literature (books, atlases on ECG) in an article on the publication “MEDIC: ECG” https://vk.com/@medic_ecg-literatura-po-ekg
There are also various ECG applications on a smartphone (reference books, atlases, tests, or all together in one program):
- Of the Russian-language programs, in our opinion, the best (and this is not advertising) are the programs from the public "ECG tests." True, they are paid (link to public - see above),
- ECG: Decoding and Tests (Ecg). The application has a small reference, it may seem useful to someone. Is free.
- ECG 100 Clinical Cases. Free app
- ECG Master. A good application with ECGs, answer them as a test. Of the minuses - if you want to open explanations for the ECG, then you need to pay 140 rubles.
Other ECG applications on smartphones in an article on the publication “MEDIC: ECG” https://vk.com/@medic_ecg-obzor-prilozhenii-po-ekg-na-smartfon
Many different useful ECG presentations at: https://vk.com/topic-150727887_41585478
Find for yourself and use various "life hacks" when analyzing the ECG. What do we mean?
We give an example. An important part of ECG analysis is the assessment of heart rate. The books usually give the formula HR = 60 / RR (sec), but it takes a relatively long time to calculate from it, and in cases where you need a quick estimate of heart rate (for example, at the patient’s bedside, at a morning conference, etc.), This is an important factor. In order to quickly understand what the patient’s heart rate is, you can use the so-called “lazy cardiologist’s formula”:
Heart rate = 300 / KBK (at an ECG recording speed of 25 mm / s), or
Heart rate = 600 / KBK (at a recording speed of 50 mm / s), where KBK is the number of large cells (5 mm) between adjacent R-R teeth.
These life hacks can be found in various presentations, articles, books and on websites, so by reading various sources you can find something new, interesting and useful.
The mathematical component
At first glance, the ECG tape is a set of mathematical concepts built by the sinusoid apparatus has a large number of parameters, each of which noted a microsecond interval in the work of the heart muscle, the totality of values gives a complete picture of the work of the heart.
As a rule, all doctors, not only cardiologists, can read a cardio tape, this is a prerequisite for emergency doctors, because according to the latest examination, it is possible to more accurately diagnose a patient with any pain in the heart. How to decrypt a cardiogram of the heart yourself?
What the cardiogram shows
The medical device records the electrical impulses that the heart muscle sends during the period of contraction and relaxation. The excitation and passive phase of myocardial cells are recorded on tape, periods of micro-stops, and contractions are clearly traced according to the received schedule.
The first thing to learn is knowledge of segments of a cardiogram (medical terms that will help in self-decoding). The curve consists of:
- A tooth is a part of the graph that has a bend (tooth) relative to the horizontal up and down.
- A segment is a straight line between the teeth.
- Interval - part of the graph, which includes a tooth and a segment.
The work of the heart muscle is fixed for some time, for the correct reading of the curve, decoding of both a single interval and a set of intervals in the time period is required.
Cardiogram of the heart: decoding and the main diagnosed diseases
Decoding a cardiogram is a long process, which depends on many indicators. Before decoding a cardiogram, it is necessary to understand all the deviations of the heart muscle.
Atrial fibrillation is characterized by irregular muscle contractions, which can be completely different. This violation is dictated by the fact that the cycle sets not the sinus node, as it should happen in a healthy person, but other cells. The heart rate in this case is from 350 to 700. In this condition, the ventricles do not completely fill with incoming blood, which causes oxygen starvation, from which all organs in the human body suffer.
An analogue of this condition is atrial fibrillation. The pulse in this state will be either below the norm (less than 60 beats per minute), or close to the normal value (from 60 to 90 beats per minute), or above the indicated norm.
On the electrocardiogram, you can see frequent and constant contractions of the atria and less often the ventricles (usually 200 per minute). This is an atrial flutter, which often occurs already in the acute phase. But at the same time, the patient tolerates it more easily than flicker. Circulatory defects in this case are less pronounced. Anxiety can develop as a result of surgical interventions, with various diseases, such as heart failure or cardiomyopathy. At the time of the examination of the person, flutter can be detected due to rapid rhythmic palpitations and pulse, swollen veins in the neck, increased sweating, general weakness and shortness of breath.
Conduction Disorder - This type of heart disorder is called blockade. The occurrence is often associated with functional disorders, but there are also the result of intoxications of a different nature (against the background of alcohol or taking medications), as well as various diseases.
There are several types of disorders that the cardiogram of the heart shows. Decryption of these violations is possible according to the results of the procedure.
Sinoatrial - with this kind of blockade, there is difficulty in exiting the impulse from the sinus node. As a result, there is a syndrome of weakness of the sinus node, a decrease in the number of contractions, defects in the circulatory system, and as a result, shortness of breath, general weakness of the body.
Atrioventricular (AV block) - characterized by a delay in excitation in the atrioventricular node for longer than a specified time (0.09 seconds). Here, several degrees of this type of blocking are distinguished.
The number of contractions depends on the magnitude of the degree, which means that a defect in the blood flow is more difficult:
- I degree - any compression of the atria is accompanied by an adequate number of contractions of the ventricles,
- II degree - a certain amount of atrial contractions remains without compression of the ventricles,
- III degree (absolute transverse block) - the atria and ventricles are compressed independently of each other, which is clearly shown by the decoding of the cardiogram.
Ventricular conduction defect. An electromagnetic pulse propagates from the ventricles to the heart muscles through the trunks of the bundle of His, its legs and branches of the legs. Blocking can occur at every level, and this will immediately affect the electrocardiogram of the heart. In this situation, it is observed that the excitation of one of the ventricles is delayed, because the electric pulse goes around the block. Doctors divide the blockage into full and incomplete, as well as permanent or intermittent blockade.
Myocardial hypertrophy is well shown by a cardiogram of the heart. Decoding on an electrocardiogram - this condition shows a thickening of individual sections of the heart muscle and stretching of the heart chambers. This happens with regular chronic overload of the body.
Next, we’ll talk about how to decipher a cardiogram by transforming the contractile function of the myocardium, there are several changes:
- Syndrome of early repolarization of the ventricles. Often, it is the norm for professional athletes and people with an inherently large body weight. It does not give a clinical picture and often passes without any changes, so the interpretation of the ECG is complicated.
- Various diffuse disorders in the myocardium. They indicate an eating disorder of the myocardium, as a result of dystrophy, inflammation or cardiosclerosis. Disorders are quite susceptible to treatment, often associated with a disorder of the water-electrolyte balance of the body, taking medications, heavy physical exertion.
- Non-individual changes ST. Явный симптом расстройства снабжения миокарда, без яркого кислородного голодания. Происходит во время дисбаланса гормонов и расстройства баланса электролитов.
- Искажение по зубцу Т, депрессия ST, низкие Т. The cat's back on the ECG shows the state of ischemia (oxygen starvation of the myocardium).
In addition to the disorders themselves, their position in the heart muscle is also described. The main feature of such disorders is their reversibility. As a rule, indicators are given for comparison with old studies in order to understand the patient's condition, since it is almost impossible to read the ECG yourself in this case. If a heart attack is suspected, additional studies are being conducted.
There are three criteria by which a heart attack is characterized:
- Stage: acute, acute, subacute and cicatricial. Duration from 3 days to a lifelong condition.
- Volume: large-focal and small-focal.
Whatever the heart attack, this is always the reason for putting a person under strict medical supervision, without any delay.
ECG results and heart rate description options
ECG results provide an opportunity to look at the state of the human heart. There are different ways to decipher the rhythm.
Sinus - This is the most common signature on an electrocardiogram. If, apart from heart rate, no other indicators are indicated, this is the most successful prognosis, then the heart is working well. This type of rhythm suggests a healthy state of the sinus node, as well as a conductive system. The presence of other records proves the defects and deviations from the norm. There is also an atrial, ventricular, or atrioventricular rhythm, which shows which cells of a particular heart section are given a rhythm.
Sinus arrhythmia - often normal in young people and children. This rhythm is characterized by the exit from the sinus node. However, the gaps between the contractions of the heart are different. This is often associated with physiological disorders. Sinus arrhythmia should be carefully monitored by a cardiologist, in order to avoid the development of serious diseases. This is especially true for people with a predisposition to heart disease, and also if arrhythmia is caused by infectious diseases and heart defects.
Sinus bradycardia - characterized by rhythmic compression of the heart muscle with a frequency of about 50 beats. In a healthy person, this condition can often be observed in a state of sleep. Such a rhythm can occur in people who are professionally involved in sports. Their ECG teeth are different from the teeth of an ordinary person.
Permanent bradycardia can characterize the weakness of the sinus node, manifested in such cases by more rare contractions at any time of the day and in any condition. If a person has pauses during contractions, then surgical intervention is prescribed to install a stimulant.
Extarsystole. This is a rhythm defect, which is characterized by extraordinary contractions outside the sinus node, beyond which ECG results show a pause of increased length, called compensatory. The patient feels a heartbeat as uneven, chaotic, too frequent, or too slow. Sometimes patients are disturbed by pauses in the heart rhythm. Often there is a sensation of tingling or unpleasant tremors behind the sternum, as well as a feeling of fear and emptiness in the stomach. Often, such conditions do not lead to complications and do not pose a threat to humans.
Sinus tachycardia - with this disorder, the frequency exceeds normal 90 strokes. There is a division into physiological and pathological. Under physiological understand the onset of such a condition in a healthy person with certain physical or emotional stress.
It can be observed after taking alcoholic beverages, coffee, energy drinks. In this case, the condition is temporary and passes quickly enough. The pathological appearance of this condition is characterized by periodic heartbeats that disturb a person at rest.
The causes of the pathological type can be fever, various infectious diseases, blood loss, long periods without water, anemia, etc. Doctors treat the underlying disease, and tachycardia is stopped only with a patient with a heart attack or acute coronary syndrome.
Paroxysmal tachycardia - in this condition, a person has a rapid heartbeat, expressed in an attack lasting from several minutes to several days. Pulse can increase to 250 beats per minute. There is a ventricular and supraventricular form of such tachycardia. The main reason for this condition is a defect in the passage of an electric pulse in a conducting system. This pathology is quite susceptible to treatment.
You can stop the attack at home with:
- Breath holding.
- Forced cough.
- Immersion in cold water of the face.
WPW syndrome - This is a subspecies of supraventricular tachycardia. The main provocateur of the attack is the additional nerve bundle, which is located between the atria and ventricles. To eliminate this defect, surgical intervention or medical treatment is required.
CLC - extremely similar to the previous type of pathology. The presence of an additional nerve bundle here contributes to the early excitation of the ventricles. The syndrome, as a rule, is congenital and manifests itself in a person with bouts of rapid rhythm, which is shown very well by the ECG teeth.
Atrial fibrillation - may be characterized by seizures or be permanent. A person feels pronounced atrial flutter.
ECG of a healthy person and signs of change
The ECG of a healthy person includes many indicators that measure human health. ECG of the heart plays a very important role in the process of detecting abnormalities in the work of the heart, the most terrible of which is myocardial infarction. Exclusively with the help of electrocardiogram data, it is possible to diagnose necrotic zones of heart attack. Electrocardiography also determines the depth of damage to the heart muscle.
ECG norms of a healthy person: men and women
ECG norms for children
ECG of the heart is of great importance in the diagnosis of pathologies. The most dangerous heart disease is myocardial infarction. Only an electrocardiogram can recognize necrotic zones of a heart attack.
Signs of myocardial infarction on an ECG include:
- the necrosis zone is accompanied by changes in the Q-R-S complex, as a result a deep Q wave appears,
- the damage zone is characterized by a displacement (elevation) of the S-T segment smoothing the R wave,
- the ischemic zone changes the amplitude and makes the T wave negative.
Electrocardiography also determines the depth of damage to the heart muscle.
How to decipher the cardiogram of the heart yourself
Not everyone knows how to decode a cardiogram of the heart. However, well versed in indicators, you can independently decipher the ECG and detect changes in the normal functioning of the heart.
First of all, it is worth determining heart rate indicators. Normally, the heart rhythm should be sinus, the rest indicate a possible development of arrhythmia. Changes in sinus rhythm, or the frequency of heart contractions, suggest the development of tachycardia (acceleration of the rhythm) or bradycardia (slowdown).
Abnormal data of the teeth and intervals are also important, since you can read the cardiogram of the heart yourself according to their indicators:
- Lengthening the QT interval indicates the development of coronary heart disease, rheumatic disease, sclerotic disorders. Shortening the interval indicates hypercalcemia.
- An altered Q wave is a signal of myocardial dysfunction.
- The sharpening and increased height of the R wave indicates hypertrophy of the right ventricle.
- Split and expanded P wave indicates hypertrophy of the left atrium.
- An increase in the PQ interval and impaired conduction of pulses occurs with atrioventricular block.
- The degree of deviation from the isoline in the R-ST segment diagnoses myocardial ischemia.
- Elevation of the ST segment over the contour is a threat of acute heart attack, a decrease in the segment registers ischemia.
There is another method for reading a cardiogram of the heart yourself. To do this, you need an electrocardiographic ruler. It helps to decipher the ECG at a speed of 25 mm / s or 50 mm / s.
Cardiolina consists of divisions (scales) that determine:
- heart rate (heart rate),
- QT interval
- isoelectric lines,
- duration of intervals and segments.
This simple and easy-to-use device is useful for everyone to independently decipher the ECG.
On the cardiogram, in addition to the line of work of the heart, the letters of the tooth are clearly visible, which show the passage of the pulse through a specific heart zone.
- P - this letter is assigned to the graphic tooth of the curve during the period of the atria during the passage of the pulse. In a healthy person, the sinusoid has a rounding tooth, looking up, up to 2.5 mm high., Lasting one tenth of a second. If the cardiogram shows sharp teeth, this is an occasion to pay attention to the work of the atria, because such a sinusoid determines pathological hypertrophy.
- Q - draws an impulse in the interventricular septum. This should be a weakly expressed segment, with the top down, up to 0.3 mm long. At the age of 5 years, the value of this tooth may be greater, this is normal for a developing heart.
- R - designation of a tooth which records an impulse at the moment of its passage on a myocardium. Its time frame during normal heart function should not exceed the value of the Q-wave, with the largest amplitude.
- S - tooth, completing the process of excitation of the ventricles. Has a directivity down to a length of 2 mm. in optimal terms.
- T is the letter designation of the tone of the muscle tissue of the heart. The longest time period of a cardiogram. During normal work, the heart has a smooth perimeter, the amplitude is 30% more than the R indicator. With a concave graph of this section of the curve, a threat of a heart attack is diagnosed, acute angles, concave inward - this is a cardiogram of a heart attack. A high amplitude of the tooth is observed in patients with autonomic disorders.
Correct decryption of segments
As well as accurate reading of tooth elements, it is necessary to read segments correctly. We will not give a breakdown of all segments, we will dwell on the examination and study of the main segment in the cardiac sinusoid.
The P-Q and S-T segments are of primary importance in self-study of their cardiogram. The rise of segments above the horizontal should not exceed 1 mm. Is an indicator of a healthy heart. The time frame depends on the heart rate, which is individual for each person. But with a primary violation of the heart rhythm, the time frame on the gap of the graphic line changes, and this is clearly visible.
The duration of the interval and its meaning.
The time intervals on the graph record the work of the heart muscle in individual phases of the heart rhythm.
The interval shows the speed with which the electrical impulse passes through the heart and the response of a particular part of the heart muscle. The most significant is the Q-T interval, during normal heart function, the pulse propagation rate does not exceed 0.45 seconds. With an increase in the interval, ischemic disease or vascular atherosclerosis is diagnosed.
ECG parameters correctness
In order to get a graphic tape with accurate indicators of the heart, the correct configuration of the device is required. Before the test, a control signal is always given, a voltage of 1 ml is turned on. volt. On a sinusoid, this is always visible as a curve deviation of 10 mm.
Also an important role in the correct understanding of the cardiogram is the knowledge of the physiological characteristics of your body. You should take into account your normal working pressure, weight, age, etc. In some cases, a cardiogram showing heart pathology may indicate normal functioning.. People who are overweight and excessively thin, with normal functioning of the heart muscle, will have opposite values of the sinusoid.
You can learn to read the cardiogram of the heart yourself, but if there is no additional medical education, or related practice, you should not independently diagnose any cardiac abnormalities, and even more so, prescribe yourself therapy. It is important to remember, depending on the saturation of the working day, cardiograms can vary significantly. After stress and scandal, it is quite possible that a sinusoid will show pathology, and after a vacation, an absolutely healthy heart. Take care of it.
The whole set of ECG lines is studied and measured mathematically, after which the doctor can determine some parameters of the heart muscle and its conducting system: heart rate, heart rate, pacemaker, conduction, electrical axis of the heart.
Today, all these indicators are investigated by high-precision electrocardiographs.
Sinus heart rhythm
This is a parameter that reflects the rhythm of the heartbeats that occur under the influence of the sinus node (normal). It shows the coordination of the work of all parts of the heart, the sequence of processes of tension and relaxation of the heart muscle.
The rhythm is very easy to identify by the highest prongs R: if the distance between them is the same throughout the recording or deviates by no more than 10%, then the patient does not suffer from arrhythmia.
The number of beats per minute can be determined not only by counting the pulse, but also by ECG. To do this, you need to know the speed with which the ECG was recorded (usually 25, 50 or 100mm / s), as well as the distance between the highest teeth (from one vertex to another).
Multiplying the recording time of one mm by cut length R-R, you can get heart rate. Normally, its performance ranges from 60 to 80 beats per minute.
The autonomic nervous system of the heart is designed in such a way that the contraction process depends on the accumulation of nerve cells in one of the zones of the heart. Normally, this is a sinus node, the impulses from which diverge throughout the nervous system of the heart.
In some cases, other nodes (atrial, ventricular, atrioventricular) can take on the role of a pacemaker. You can determine this by examining P wave - subtle, located just above the contour.
What is post-myocardial cardiosclerosis and why is it dangerous? Is it possible to cure it quickly and effectively? Are you at risk? Find out everything!
The reasons for the development of cardiosclerosis of the heart and the main risk factors are discussed in detail in our next article.
Detailed and comprehensive information on the symptoms of cardiosclerosis of the heart can be found here.
An indicator based on the process of ventricular excitation. Mathematical analysis of Q, R, S teeth in I and III leads allows you to calculate a certain resulting vector of their excitation. This is necessary to establish the functioning of the branches of the bundle of His.
The resulting angle of the axis of the heart is estimated by the value: 50-70 ° normal, 70-90 ° deviation to the right, 50-0 ° deviation to the left.
Cogs, segments and intervals
Prongs - ECG sections lying above the contour, their meaning is as follows:
- P - reflects the processes of contraction and relaxation of the atria.
- Q, S - reflect the processes of excitation of the interventricular septum.
- R - The process of excitation of the ventricles.
- T - The process of ventricular relaxation.
Intervals - ECG sections lying on the isoline.
- Pq - reflects the propagation time of the impulse from the atria to the ventricles.
Segments - ECG sections, including the interval and the tooth.
- QRST - the duration of ventricular contraction.
- ST - time of complete excitation of the ventricles.
- TP - time of electric diastole of the heart.
This phenomenon characterized by a heart failure. A person feels a temporary increase in the frequency of contractions, followed by a pause. It is associated with the activation of other pacemakers, sending along with the sinus node an additional volley of pulses, which leads to an extraordinary reduction.
Characterized by a change in the periodicity of the sinus rhythmwhen the pulses arrive at different frequencies. Only 30% of such arrhythmias require treatment, because able to provoke more serious diseases.
In other cases, this can be a manifestation of physical activity, a change in hormonal levels, the result of a fever and does not threaten health.
The opposite phenomenon, characterized by an increase in heart rate more than 90 beats per minute. In some cases, temporary tachycardia occurs under the influence of strong physical exertion and emotional stress, as well as during illness associated with fever.
In addition to the sinus node, there are other underlying pacemakers of the second and third orders. Normally, they conduct impulses from a first-order pacemaker. But if their functions are weakened, a person can feel weakness, dizzinesscaused by inhibition of the heart.
It is also possible to lower blood pressure, because ventricles will contract less frequently or irregularly.
Why there may be differences in performance
In some cases, when re-analyzing the ECG, deviations from previously obtained results are detected. With what it can be connected?
- Different time of day. Обычно ЭКГ рекомендуется делать утром или днём, когда организм ещё не успел подвергнуться влиянию стрессовых факторов.
- Нагрузки. Очень важно, что бы при записи ЭКГ пациент был спокоен. Выброс гормонов может увеличить ЧСС и исказить показатели. Кроме того, перед обследованием также не рекомендуется заниматься тяжёлым физическим трудом.
- Eating. Digestion processes affect blood circulation, and alcohol, tobacco and caffeine can affect heart rate and pressure.
- Electrodes. Incorrect overlapping or accidental bias can seriously affect performance. Therefore, it is important not to move during recording and degrease the skin in the area of application of electrodes (the use of creams and other skin products before examination is highly undesirable).
- Background. Sometimes, extraneous devices can affect the operation of the electrocardiograph.
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Additional examination methods
Method long-term study of the heart, possible thanks to a portable compact tape recorder, which is able to record the results on a magnetic film. The method is especially good when it is necessary to study periodically occurring pathologies, their frequency and time of occurrence.
Unlike a normal ECG recorded at rest, this method is based on an analysis of the results after exercise. Most often, this is used to assess the risk of possible pathologies that were not detected on a standard ECG, as well as when prescribing a rehabilitation course for patients after a heart attack.
Allows analyze heart sounds and sounds. Their duration, frequency and time of occurrence are correlated with the phases of cardiac activity, which makes it possible to evaluate the valve function, the risks of developing endo- and rheumatic heart disease.
A standard ECG is a graphic representation of the work of all parts of the heart. Its accuracy can be affected by many factors, therefore follow doctor's recommendations.
The examination reveals most of the pathologies of the cardiovascular system, however, additional tests may be required for an accurate diagnosis.
Finally, we suggest watching a video course on decoding "ECG is within the power of everyone":