Algorithms for ECG analysis in outpatient practice

Surely many times in your life you have encountered a situation when you need to decipher a “tape”: during an exam in propaedeutics of internal diseases, when studying a medical history (and not necessarily in the department of therapy or cardiology), or even when consulting a friend of your mother who turned to you with the words “you’re a doctor.” If in all these situations you thought: “I think I studied electrocardiography in the 2nd or 3rd year of medical school, but when I pick up an electrocardiogram in my hands, I understand little. We need to do something about this,” then this article is definitely for you. If you are already well versed in electrocardiography, then in any case, the links to various sources provided in this article may be useful to you.

Application area

Due to its accessibility, harmlessness, and lack of discomfort, ECG is suitable for examining all categories of the population: pregnant, lactating women, children, elderly people, and seriously ill patients. Using the procedure you can:

• determine the frequency and regularity of heart contractions;
• detect acute or chronic myocardial damage (ischemia, infarction);
• identify disturbances in electrolyte metabolism and intracardiac conduction;
• assess the physical condition of the organ;
• detect signs of non-cardiac diseases (for example, pulmonary embolism).

The ECG diagnostic method has no analogues. In combination with other necessary tests, it makes it possible to quickly and objectively make a diagnosis and select appropriate treatment, including surgical intervention.

Further study of the ECG

Once you have mastered the basics of the ECG and have learned to confidently look at the electrocardiogram, knowing what you should analyze on it and how to interpret the main changes you find, you need 2 things - first of all, practice, as well as in-depth study of individual ECG topics.

ECG practice

The main thing you need to understand about ECG practice is that it must be regular. ECG analysis and interpretation is a skill that needs to be practiced. It may be difficult at first and there will be many small questions about various details. This is normal, the main thing is to try to sort out unclear questions and look into books and reference books on ECG more often.

After some time of viewing ECGs, you will feel something like a “point of no return”, when you will be able to look at the ECG comprehensively, confidently excluding or confirming the main pathologies. However, there will still be complex, controversial cases that will force you to read more in-depth books and articles on ECG and ask your colleagues for advice.

Where can I find an ECG for regular practice?

There are various sources: atlases, public pages, websites, videos, programs for smartphones.

Subscribe to VKontakte public pages:

1. MEDIC: ECG. In this group, every day in the morning an ECG is posted with possible answers 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 here. Link: https://vk.com/medic_ecg
2. ECG tests. Another great public page with ECG tests every day. Its admin also translated many different books on ECG from English, created several reference programs on ECG for computers and phones, all of this can be found in the group. Link: https://vk.com/club122935445

Websites:

1. https://lifeinthefastlane.com/ecg-library/ - This site has many different ECG examples. It is also one of the best sites that can be used as a reference when you don't understand something, and even to some extent as a study guide.

2. Wikipedia on ECG: https://en.ecgpedia.org/index.php?title=Main_Page

3. https://www.ecg-quiz.com/

4. https://www.skillstat.com/tools/ecg-simulator - online ECG simulator (see picture) Try your hand at determining the rhythm on the monitor at speed! You can also download the ECG simulator to your computer: https://cloud.mail.ru/public/6aLN/9xaABKDea

Even more useful public pages and websites on ECG can be found in this article on “MEDIC: ECG” - https://vk.com/@medic_ecg-ssylki-na-resursy-po-ekg

Types of ECG of the heart

There are several types of ECG of the heart, thanks to which you can evaluate the work of the heart muscle in various conditions and conditions.

Classical electrocardiography

It takes 5-10 minutes and allows you to study the condition of the heart at the time of the procedure. It is used to determine the size of the chambers, heart rate, conductivity of the heart muscle, and evaluate the blood supply to the myocardium at rest. However, many cardiac pathologies appear only during sleep or physical activity, so it is extremely difficult to identify them during a short visit to a cardiologist.

Holter monitoring (Holter ECG)

A complex, in-depth study that provides continuous recording of cardiac muscle parameters for 24-72 hours or up to 10 days (if necessary). Recording is carried out with a special device that is carried with you on a belt or belt. Electrodes are attached to the surface of the skin in certain places. After which the person leads a normal life (works, walks). At the same time, he notes in a notebook when he experiences pain in the heart area, takes medications, and begins active physical activity. The data obtained is reviewed and corrected by the doctor, after which he draws conclusions and prescribes treatment.

Interesting! There are portable devices that are implanted under the skin near the heart to record information throughout the year.

Algorithms for ECG analysis in outpatient practice

Electrocardiography (ECG), despite more than 100 years of history of use in clinical practice, still remains a popular method for diagnosing cardiovascular pathology. At the beginning of the 20th century, Vladimir Filippovich Zelenin first began to conduct systematic electrocardiographic studies of patients in the clinic [1]. The method is of particular importance in outpatient general medical practice due to its information content and accessibility. The presence of portable devices allows for repeated use, including at home.

It is important that every doctor using this method can quickly and correctly interpret the data obtained. Today, a doctor has a large amount of available literature on clinical electrocardiography, which, as a rule, is addressed to functional diagnostic doctors [2–6].

The ECG analysis algorithms we have developed summarize and make data from specialized literature more accessible to primary care physicians. The practical application of these algorithms in practice, over many years of teaching experience to general practitioners, indicates the rationality and effectiveness of the presented methods for analyzing electrocardiograms for mastering the basics of electrocardiography and their use in clinical practice [7].

The main purpose of using these algorithms is to facilitate the development of techniques for interpreting electrocardiograms using simplified, but at the same time, academic methods of ECG analysis. The proposed algorithms make it possible to quickly answer the first important question facing an outpatient doctor: “norm - pathology”, and then, based on the clinical principle of diagnosis “symptom - syndrome - nosology”, which is close and understandable to a practicing physician, formulate an electrocardiographic conclusion.

The electrocardiogram reveals signs of deviation from the norm (ECG symptoms), grouped by one mechanism of development into ECG syndromes, and when compared with the age, gender, constitution of the patient, and clinical picture of the disease, an electrocardiographic conclusion (ECG diagnosis) is formulated.

The basis of the clinical diagnosis is the features of the clinical picture of the disease (onset, risk factors, clinical symptoms and syndromes, rate of progression), and electrocardiography plays an important but auxiliary role.

For an internist who does not have special knowledge of functional diagnostics, a strict procedure for ECG analysis is necessary. The use of the algorithm requires a strict sequence of analysis of the main elements of the electrocardiogram, which should include the following parameters:

• reference millivolt evaluation (standard millivolt = 10 mm);
• assessment of ECG registration speed (50 mm/sec or 25 mm/sec);
• determination of the main rhythm (sinus, ectopic);
• determining the correctness of the rhythm (equality of RR intervals; maximum and minimum RR distances differ from each other by less than 0.15 sec);
• counting heart rate (HR = 60: RR (sec) or using a ruler);
• characteristics of teeth, intervals, segments (table);
• determination of voltage (sufficient - if in at least one standard or unipolar lead the amplitude of the QRS complex is > 5 mm and in at least one of the chest leads > 8 mm);
• determination of the electrical axis of the heart;
• electrocardiographic report;
• comparison of ECG data with: the age and constitution of the patient;
• physiological characteristics (pregnancy, etc.);
• clinical picture and duration of the disease;
• ongoing therapy.

For each element of the ECG, it is necessary to analyze certain parameters, compare them with the norm, highlight deviations from the norm and make a conclusion.

In table The parameters that require analysis and their normal characteristics are listed, which makes it possible to identify the main deviations from the norm.

Rice. 1–3 directly reflect ECG diagnostic algorithms based on the “syndrome - nosology” principle. Following the algorithm requires the doctor to consistently and thoroughly analyze the ECG and most likely excludes the possibility of missing a significant pathology.

ECG examples

Thus, the proposed analysis of the parameters of ECG elements according to a specific plan, being the first step, gives direction to deciphering the electrocardiogram using literature sources on clinical medicine and functional diagnostics.

Literature

1. Zelenin V.F. Electrocardiogram, its significance for physiology, general pathology, pharmacology and clinics // Military Med. zhurn., 1910. T. 228. P. 677.
2. Orlov V.N. Guide to electrocardiography. M.: Medicine, 1983. 528 p., ill.
3. Syrkin A. L. ECG for a general practitioner. M.: OJSC “Publishing House “Medicine”, 2006. 176 p., ill.
4. Ebert G. Simple ECG analysis: interpretation, differential diagnosis. M.: “Logosphere”, 2010. 279 p.
5. Proceedings of the 13th Congress “Clinical Electrocardiography”, April 25–26, 2012, Kaliningrad.
6. Zimmerman F. Clinical electrocardiography. Second edition. 2016. 424 p. ISBN 978–5-9518–0164–7, 0–07–14302–8
7. Chegaeva T.V. Algorithms for ECG diagnostics in general medical practice / Edited by Academician of the Russian Academy of Sciences I.N. Denisov. Moscow, 2011.

T. V. Chegaeva, Candidate of Medical Sciences E. O. Samokhina, Candidate of Medical Sciences T. E. Morozova1, Doctor of Medical Sciences, Professor

Federal State Autonomous Educational Institution of Higher Education First Moscow State Medical University named after. I. M. Sechenova Ministry of Health of the Russian Federation, Moscow

1 Contact information

Algorithms for ECG analysis in outpatient practice / T. V. Chegaeva, E. O. Samokhina, T. E. Morozova

For citation: Attending physician No. 2/2018; Page numbers in the issue: 20-23 Tags: heart, electrocardiographic report, diagnosis

In what cases is an ECG prescribed?

A routine examination is indicated for all patients admitted to the hospital department. Unscheduled and emergency electrocardiography is carried out in case of development or suspicion of myocardial damage of any nature (toxic, inflammatory, ischemic).

Direct indications for an ECG are:

• metabolic syndrome;
• heartbeat instability;
• chronic diseases of the cardiovascular system;
• circulatory disorders;
• changes in myocardial structure;
• endocrine diseases;
• rheumatism;
• monitoring the operation of the pacemaker;
• chronic respiratory pathologies;
• preparation for surgery.

Medical indications for an ECG are:

• periodic pain in the chest, back, neck;
• shortness of breath and difficulty breathing both at rest and after physical exertion;
• high blood pressure;
• swelling of the lower extremities, constant weakness, fainting;
• previous stroke/myocardial infarction;
• age over 40 years (annually).

Pregnant women undergo electrocardiography upon registration, as well as in the presence of alarming symptoms (fainting, dizziness, changes in blood pressure).

An ECG is sometimes recommended in the following situations:

• medical examination (admission to kindergarten, school, secondary and higher educational institutions);
• preventive examination;
• before the driver's license test;
• issuing a certificate for visiting the pool and practicing active sports;
• registration for sanatorium treatment.

The procedure has no contraindications, except for patients with chest deformation, purulent wounds and inflammatory diseases of the skin in the thoracic area.

How to prepare for the procedure, how it is carried out, who does the decoding

Electrocardiography does not require special preparation. The patient can undergo examination at any time. Before visiting the functional diagnostics office, you need to take care of your appearance, since you will have to expose your chest, forearms and shins, to which the electrodes are attached.

Important! Before the examination, it is not recommended to overeat, smoke, worry, go to the gym or run, drink alcohol, coffee, or energy drinks.

Taking an ECG looks like this: the patient removes the necessary areas of the body from clothing and lies down on the couch. The doctor or nurse degreases the skin with a special product (or water) so that the “suction cups” have better contact with the body, applies electrodes, turns on the device and makes a recording. With the results obtained and a preliminary transcript, the patient is sent to the attending physician.