How does an electrocardiogram work. What can ECG reveal about heart health. Why are ECGs important for diagnosing cardiac conditions. What do the different waves on an ECG represent. How is an ECG administered. What are the components of a 12-lead ECG.

Understanding the Basics of Electrocardiograms (ECGs)

An electrocardiogram, commonly known as an ECG or EKG, is a non-invasive diagnostic tool that measures the heart’s electrical activity during the cardiac cycle. This powerful medical instrument provides valuable insights into heart function, helping clinicians assess heart rate, rhythm abnormalities, and potential cardiac issues.

The term “EKG” originates from the Dutch word “elektrokardiogram,” coined by Wilhelm Einthoven, who received the Nobel Prize for his pioneering work in 1924. Today, both ECG and EKG are used interchangeably in medical settings.

How is an ECG Administered?

ECGs are performed using electrodes placed on the skin’s surface to detect internal electrical activity. These electrodes are connected to a machine that plots the recorded voltage over time. Modern ECGs typically use a 12-lead system, which involves placing 10 electrodes on specific areas of the body:

• Six electrodes on the chest
• One electrode on each limb

This configuration provides 12 different electrical “views” of the heart, offering a comprehensive assessment of cardiac function.

Decoding the ECG Waveform: Key Components

An ECG waveform consists of several distinct components, each representing a specific phase of the cardiac cycle. Understanding these components is crucial for interpreting ECG results accurately.

P Wave: The Beginning of the Heartbeat

The P wave is the first deflection on an ECG tracing. It represents the electrical activity that originates in the sinoatrial (SA) node, the heart’s natural pacemaker, and spreads through the atria. This electrical signal stimulates atrial contraction, pushing blood into the ventricles.

PR Interval: Atrial to Ventricular Conduction

The PR interval measures the time between the start of the P wave and the beginning of the QRS complex. It reflects the conduction time from the atria to the ventricles through the atrioventricular (AV) node.

QRS Complex: Ventricular Depolarization

The QRS complex is the most prominent feature of an ECG tracing. It represents ventricular depolarization, which leads to the contraction of the ventricles. The QRS complex consists of three waves:

1. Q wave: The initial downward deflection
2. R wave: The subsequent upward deflection
3. S wave: The final downward deflection

As the electrical signal travels through the bundle of His and Purkinje fibers, it triggers ventricular contraction, pumping blood out of the heart through the pulmonary artery and aorta.

ST Segment: Ventricular Depolarization to Repolarization

The ST segment represents the period between ventricular depolarization and repolarization. It appears as a flat, isoelectric line on the ECG tracing. Changes in the ST segment can indicate various cardiac conditions, such as myocardial ischemia or infarction.

T Wave: Ventricular Repolarization

The T wave represents ventricular repolarization, during which the heart’s electrical activity returns to baseline. After this phase, the ventricular muscles relax, preparing for the next cardiac cycle.

Clinical Applications of ECGs in Cardiac Diagnostics

ECGs play a crucial role in diagnosing and monitoring various heart conditions. Healthcare professionals rely on ECG data to assess cardiac function and make informed treatment decisions.

Identifying Arrhythmias

Arrhythmias are abnormal heart rhythms that can be detected through ECG analysis. Common types of arrhythmias include:

• Atrial fibrillation
• Ventricular tachycardia
• Bradycardia
• Heart block

By examining the regularity and morphology of ECG waves, clinicians can identify and classify these rhythm disturbances.

Diagnosing Myocardial Infarction

ECGs are invaluable in diagnosing myocardial infarction (heart attack). Characteristic changes in the ST segment and T wave can indicate ongoing or recent myocardial damage. Early detection of these changes is crucial for timely intervention and improved patient outcomes.

Assessing Structural Heart Disease

While not as definitive as imaging studies, ECGs can provide clues about structural heart abnormalities. For example:

• Left ventricular hypertrophy may be indicated by increased QRS amplitude
• Right ventricular hypertrophy can manifest as right axis deviation
• Atrial enlargement may be suggested by changes in P wave morphology

Advanced ECG Techniques and Technologies

As medical technology advances, new ECG-based techniques are emerging to enhance cardiac diagnostics and monitoring.

Holter Monitoring

Holter monitors are portable ECG devices that record heart activity continuously for 24 to 48 hours or longer. They are particularly useful for detecting intermittent arrhythmias or evaluating symptoms that occur outside of clinical settings.

Exercise Stress Testing

Exercise stress tests combine ECG monitoring with physical exertion to assess the heart’s response to increased demand. This technique can help diagnose coronary artery disease and evaluate exercise capacity in patients with known heart conditions.

Signal-Averaged ECG

Signal-averaged ECG is a specialized technique that enhances the detection of subtle electrical abnormalities in the heart. It is particularly useful for identifying patients at risk for ventricular arrhythmias.

Interpreting ECG Results: Challenges and Considerations

While ECGs provide valuable information about cardiac function, interpreting the results requires skill and experience. Several factors can influence ECG readings and their interpretation:

• Patient positioning and movement
• Electrode placement accuracy
• Presence of electrolyte imbalances
• Effects of medications
• Coexisting medical conditions

Healthcare professionals must consider these factors when analyzing ECG tracings to avoid misinterpretation and ensure accurate diagnosis.

The Future of ECG Technology: Innovations and Trends

The field of ECG technology is continuously evolving, with new innovations promising to enhance cardiac diagnostics and patient care.

Wearable ECG Devices

Wearable ECG devices, such as smartwatches and patches, are gaining popularity for continuous cardiac monitoring. These devices allow for long-term data collection in real-world settings, potentially improving the detection of intermittent arrhythmias and other cardiac events.

Artificial Intelligence in ECG Interpretation

Artificial intelligence (AI) algorithms are being developed to assist in ECG interpretation. These AI-powered tools have the potential to:

• Improve diagnostic accuracy
• Reduce interpretation time
• Identify subtle patterns that may be missed by human readers
• Predict future cardiac events based on ECG data

While AI shows promise in ECG analysis, it is important to note that these tools are intended to supplement, not replace, the expertise of trained healthcare professionals.

Remote ECG Monitoring

Advancements in telemedicine and remote monitoring technologies are enabling healthcare providers to assess ECG data from patients in remote locations. This capability can improve access to cardiac care, particularly for patients in rural or underserved areas.

ECG Education and Training: Ensuring Accurate Interpretation

Given the importance of ECGs in cardiac diagnostics, proper education and training for healthcare professionals are essential. Key aspects of ECG education include:

• Understanding the underlying physiology of the cardiac conduction system
• Recognizing normal and abnormal ECG patterns
• Identifying common artifacts and technical issues
• Correlating ECG findings with clinical presentation
• Staying updated on new ECG technologies and interpretation guidelines

Continuing education programs and simulation-based training can help healthcare providers maintain and improve their ECG interpretation skills.

ECG in Conjunction with Other Cardiac Diagnostic Tools

While ECGs provide valuable information about cardiac electrical activity, they are often used in combination with other diagnostic tools to provide a comprehensive assessment of heart health. Complementary cardiac diagnostic techniques include:

Echocardiography

Echocardiography uses ultrasound waves to create real-time images of the heart’s structure and function. When combined with ECG data, echocardiography can provide a more complete picture of cardiac health, allowing clinicians to assess both electrical and mechanical aspects of heart function.

Cardiac CT and MRI

Advanced imaging techniques such as cardiac computed tomography (CT) and magnetic resonance imaging (MRI) offer detailed views of cardiac anatomy and function. These modalities can help confirm or further investigate abnormalities detected on ECG, particularly in cases of suspected structural heart disease or coronary artery disease.

Cardiac Biomarkers

Blood tests measuring cardiac biomarkers, such as troponin and B-type natriuretic peptide (BNP), can provide additional information about heart health. When interpreted alongside ECG findings, these biomarkers can help diagnose conditions like myocardial infarction and heart failure more accurately.

By combining ECG data with information from these complementary diagnostic tools, healthcare providers can develop a more comprehensive understanding of a patient’s cardiac status and tailor treatment plans accordingly.

Decoding the Heart: What Is an ECG?

Posted on 2/13/20 by Laura Snider

If you’ve explored our newest app, Physiology & Pathology, you might have noticed that one of the tools you can use alongside the beating heart is a follow-along ECG. It looks a little something like this:

So, what can a bunch of squiggles tell doctors about the way someone’s heart is functioning? Quite a lot, actually. Today we’re going to talk about what an ECG is, the basics of how it works, and what exactly it shows clinicians about a person’s heart. 

What is an ECG? 

Let’s start off with the most basic question: what is an ECG? The simplest answer is that it’s a noninvasive method of measuring the heart’s electrical activity during the cardiac cycle. Doctors can see how long an electrical signal takes to pass through the heart, and how big the changes in voltage are as it does so. This can help them figure out whether a patient’s heart rate is normal or abnormal, and whether certain parts of the heart are getting overworked. 

Best of all, the ECG doesn’t cause the patient any pain (although removing the electrodes after the procedure feels like removing a bandaid). 

Fun fact: You might have heard an ECG referred to as an EKG. This is because Wilhelm Einthoven, the person who pioneered the name for the method and received the Nobel Prize for its discovery in 1924, did his work in the Netherlands, so he used the Dutch term “elektrokardiogram”—thus the EKG abbreviation.

How is an ECG administered? 

How do you measure what’s going on in the heart without poking around inside a person’s body? You use electrodes that can pick up internal electrical activity from the surface of the skin. These electrodes are connected via wires to a machine that plots the recorded voltage over time. 

Image from Physiology & Pathology.

The ECGs given today are referred to as “12-lead” ECGs, because they use 10 electrodes to show 12 different electrical “views” of the heart. (Note: A “lead” can either refer to an electrode/wire itself or a view of the heart obtained using a combination of electrodes.) Six electrodes are placed on the patient’s chest, and one electrode is placed on each of their limbs.

What does an ECG measure?

A single round of the cardiac cycle shows up in 3 main “waves” on an ECG—the P wave, the QRS complex, and the T wave. These waves reflect the activities of the heart’s electrical conduction system, which is composed of specialized muscle fibers.

P wave
A heartbeat starts with the generation of an electrical signal at the sinoatrial node (SA node)—the heart’s natural pacemaker—and that signal subsequently passes to the atrioventricular node (AV node). On an ECG, this is what the P wave, that first little blip, represents. 

Footage from Physiology & Pathology.

The electrical signal that begins at the SA node and travels to the AV node stimulates the atria of the heart to contract, pushing blood into the ventricles. Remember—the electrical signal occurs ever so slightly before the actual muscle movements! 

PR Interval
The PR interval is the time between the start of the P wave and the start (the first deflection) of the QRS complex. 

QRS wave complex
The big spike in the middle of the ECG is the QRS complex, which reflects the electrical signals leading to ventricular contraction. It’s made up of multiple waves, but they’re usually grouped together for analysis. 

Once the electrical signal reaches the AV node, it passes on to the atrioventricular bundle (bundle of His), and then it travels down the bundle fibers to the Purkinje fibers. This stimulates the contraction of the ventricles, pushing blood out of the heart through the pulmonary artery and aorta.

Footage from Physiology & Pathology.

ST Interval
The ST interval, or ST segment, is the time between the end of the QRS complex and the start of the T wave. This means it represents “the period of zero potential between ventricular depolarization and repolarization”—in other words, the pause between contraction and recovery.

T wave
The T wave represents the heart’s electrical activity returning to baseline—ventricular repolarization. (Atrial repolarization occurs during the QRS complex, so it isn’t clearly visible on the ECG readout.) After ventricular repolarization, the muscles of the ventricles relax. 

Footage from Physiology & Pathology. 

How do ECGs help diagnose heart conditions?

ECGs can help medical professionals identify and/or monitor multiple types of heart conditions, including arrhythmias, blocked arteries, heart failure, heart attacks, and damage to the heart. Usually, an ECG is used when someone shows symptoms of a heart problem, such as chest pain, dizziness, fatigue, or shortness of breath.

ECGs also help doctors to measure the effectiveness of treatments like pacemakers and medications. Recent technology could soon allow for ECG to detect episodes of hypoglycemia (low blood sugar) in a noninvasive way, which would be great news for people with diabetes. 

ECG readouts for particular heart conditions often have specific identifiable characteristics with respect to the different waves and intervals. Here are a few examples.

Atrial fibrillation is an arrhythmia in which the atria of the heart are not pumping normally—chaotic electrical signals cause them to quiver instead of contracting in a regular rhythm. Untreated AFib can result in a person being twice as likely to die of a heart-related cause and five times as likely to suffer from a stroke. 

On an ECG, AFib can be identified by the absence of a normal P wave. The QRS wave is still there but occurs at irregular intervals.

A “sawtooth” P wave is characteristic of atrial flutter, which is not the same as atrial fibrillation but is closely related.  

Abnormalities of the ST segment can mean several things, depending on their nature and what leads/electrodes they’re visible on. Depression of the ST segment on certain leads can indicate ischemia, which means that impaired blood flow to the heart tissue is depriving that tissue of oxygen. Elevation of the ST on certain leads can be a sign of myocardial infarction (MI), aka a heart attack. MI happens when tissue death occurs as the result a blockage in the coronary arteries preventing adequate blood from reaching the heart muscles. 

Essentially, ECG is an important tool in cardiology because medical professionals must be able to assess the performance of the heart’s conduction system in order to diagnose and keep track of heart conditions such as arrhythmias and myocardial injury. 

If you want to learn more about the cardiac cycle and cardiovascular pathologies, open up Physiology & Pathology and watch the beating heart in action! 

For an in-depth look at the structures that make up the heart, check out our Build a Heart eBook! 

Be sure to subscribe to the Visible Body Blog for more anatomy awesomeness! 

Are you an instructor? We have award-winning 3D products and resources for your anatomy and physiology course! Learn more here.

Additional Sources: 

• American Heart Association: Electrocardiogram (ECG or EKG)
• Conquering the ECG – Cardiology Explained
• Harvard Health Letter: Understanding the ECG: Reading the waves
• Medlineplus.gov: Electrocardiogram
• Understanding the 12-lead ECG part I : Nursing2020

Topics

• Anatomy & Physiology,
• Pathology

Tests for diagnosing heart conditions – Heart tests

To identify common heart conditions you’ll need to have some tests. These could include:

• blood pressure tests
• checking your pulse
• X-rays
• stress tests

Checking your pulse

Taking a pulse is a very important part of heart health checks. It measures the number of heart beats per minute, assesses if the pulse is regular or not, and identifies the strength of the pulse. Your nurse or doctor may check your pulse, or you can check it yourself.

More about atrial fibrillation

How to check your pulse
(https://www.youtube.com/watch?v=OXFKDfoOYmE)

Watch NHS Fife’s video on how to check your own pulse, and how important it is to go and talk to your doctor or nurse if you notice that your pulse isn’t regular.

Blood pressure

Blood pressure is an important measurement that can be taken by your doctor, nurse or healthcare assistant. It’s recorded as two readings:

• systolic pressure (higher reading) – this records the pressure within the blood vessels as the heart contracts and forces blood out into the arteries
• diastolic pressure (lower reading) – this records the pressure when the heart fills up with blood again

Your blood pressure fluctuates throughout the day, depending on what you’re doing. The “white coat effect” is when your blood pressure rises at the thought of having your blood pressure taken. To prevent this when you get your BP taken, try to relax. You might be asked to sit quietly for at least five minutes beforehand. Tell the person taking your blood pressure about any prescribed medicines you’re taking.

Sometimes your doctor may want you to monitor your blood pressure at home over a period of time. This can be either by 24-hour ambulatory monitoring or by home monitoring.

Read more from the British Hyperternsion Society on home blood pressure testing

British Heart Foundation have information on measuring your blood pressure at home

Echocardiogram

An echocardiogram – or “echo” – is an ultrasound scan of the heart. It uses high frequency sound waves to create an image of your heart.

This is a painless procedure that is usually performed in hospital or in an outpatient clinic. You’ll have jelly applied to your bare chest, and an experienced operator will move the probe around your chest to get good views of your heart.

It can check:

• the size of the heart
• how well the heart muscle is contracting and relaxing
• how well the valves are working

More about having an echocardiogram

Electrocardiogram

An electrocardiogram (ECG) is a test that records the electrical activity of the heart. The ECG reflects what’s happening in different areas of the heart and helps identify any problems with the rhythm or rate of your heart. The ECG is painless and takes around 5-10 minutes to perform.

More about having an electrocardiogram

24-hour or ambulatory electrocardiogram

In this test, electrodes are connected to a small box and attached to a belt. You wear this belt for 24 hours, as you go about your normal daily activities. The ECG will be monitoring and will be able to record any abnormalities over the day. You’ll also be asked to record any symptoms. Then this can be assessed by the electrophysiologist or cardiologist.

Stress test

This stress test – or exercise tolerance test (ETT) or treadmill test – is similar to an ECG but records the activity of the heart as it works harder, for example while you’re walking on a treadmill. This “exercise” ECG records how the heart responds to exercise.

Having an exercise ECG (stress test)
(https://www.youtube.com/watch?v=24UfNoTUzfw)

Watch this video by British Heart Foundation of someone being prepared for, and undertaking, an ETT.

Tilt test

A tilt test allows the doctor to monitor your blood pressure and heart rate when you’re lying down and standing up.

This test is designed to assess symptoms you may have been experiencing, like light-headedness or dizziness, and to see if your symptoms are related to your blood pressure or heart rate.

The test will normally be done as an outpatient appointment in an electrophysiology department.

Having a tilt test
(https://www.youtube.com/watch?v=0zYwKl-YBtQ)

Watch this British Heart Foundation video of a tilt test being performed.

Magnetic resonance imaging (MRI)

This painless scan uses a magnetic field inside a scanning machine to produce images of the heart and blood vessels.

It’s useful for checking problems with structure of heart and blood supply.

It’s very helpful in getting images from people whose vessels and heart anatomy are difficult to see using angiography.

Cardiac computed tomography (Cardiac CT)

Cardiac CT uses a special X-ray machine, which moves around your body and takes detailed 3-D images of your heart.

Thallium scan (myocardial perfusion scintigraphy)

This scan shows how well blood is reaching the heart muscle through your coronary arteries. A small amount of thallium (radioactive substance) is injected into a vein, and a special camera moves around your heart. The camera picks up traces of thallium and produces pictures.

As thallium doesn’t travel well to areas where there’s a poor blood supply, the pictures can be used to see how well blood is reaching your heart. It’s a useful alternative to an exercise test if this can’t be done or when specific information on your heart muscle is needed which a treadmill exercise test can’t provide.

This is done at rest and during exercise.

The very low levels of radiation used are considered to be safe.

Coronary angiogram

A coronary angiogram is a type of X-ray used to examine the coronary arteries supplying blood to your heart muscle. It’s considered to be the best method of diagnosing coronary artery disease – conditions that affect the arteries surrounding the heart.

During the test, a long, flexible tube called a catheter will be inserted into a blood vessel in either your groin or arm. The tip of the catheter will then be fed up to your heart and coronary arteries.

Special dye will then be injected through the fine catheter into your coronary arteries, and X-ray images will be taken. These images created during angiography are called angiograms.

These images will be used to identify narrowing or blockage of the arteries that may be responsible for your symptoms. This test is also sometimes required to reach a diagnosis for patients with heart valve and muscle disease.

More about cardiac catheterisation and coronary angiography

Having a coronary angiogram
(https://www.youtube.com/watch?v=nnQ059DTBbQ)

Watch a short video where Dr Peter Henriksen, Consultant Cardiologist for NHS Scotland, provides an outline and explanation of the coronary angiogram procedure.

Blood tests

There are a number of blood tests that can be done to rule out other causes of heart symptoms, and to measure different levels within the body that can affect the heart. You may also get blood tests done if you begin a new heart medicine. 

The most common are:

• Full Blood count (FBC) – this test measures the levels of red blood cells, white blood cells and platelets. It also measures the haemoglobin (oxygen carrying component of red blood cells).
• Urea and Electrolytes (Us and Es) – urea levels help to monitor how the kidneys are working. Electrolytes help to stabilise the heart rhythm.
• Glucose – this test measures the level of sugar in the blood.
• Liver and thyroid function – these tests measure liver function and the thyroid function.
• Troponin blood test – troponin is a protein which is released into the blood stream when the heart muscle is damaged. The troponin level provides a quick and accurate measure of any heart muscle damage. It’s used to help in the assessment following suspected heart attack. It may be taken on admission to hospital and/or 12 hours from the onset of symptoms.
• Cholesterol level and lipid profile.
• Natriuretic peptides – an indicator of heart failure.

More about having a blood test

Chest X-ray

A chest X-ray is useful for showing the size and shape of the heart and detecting chest disorders. This can provide doctors additional information about your symptoms (which can often relate to both chest and heart conditions) and can also show any fluid in the lungs, which may be caused by heart disease.

More about having an X-ray

Source:
Chest Heart & Stroke Scotland – Opens in new browser window

Last updated:


19 January 2023

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Electrocardiogram (ECG): interpretation of results – Loritome Clinic

Electrocardiogram (ECG): interpretation of results

By: Administrator | Tags: interpretation of ECG results, interpretation of ECG, ECG, ECG norm, Electrocardiogram, electrocardiogram interpretation of results | Comments:
0 | June 24, 2021

Electrocardiography is a simple and informative study that determines heart rate indicators. The cardiograph records the activity of the heart and records its parameters on paper. To evaluate them and draw conclusions about the patient’s condition, it is necessary to decipher the cardiogram. ECG interpretation is performed manually by comparing the characteristics of the graph with special tables or using computer programs to interpret the ECG results.

When and who needs to undergo a heart test

The doctor prescribes this diagnostic test in the following cases:

• high blood pressure;
• chest pain, shortness of breath;
• dizziness or fainting;
• heart murmurs;
• disturbed heart rhythm;
• rheumatism;
• diabetes.

An electrocardiogram is also prescribed for overdose of certain medications. ECG is part of the examination during the medical examination, prof. examination, pregnancy, preparation for operations.

This is not an exhaustive list of cases where an ECG is needed. In addition, it is performed t without a doctor’s referral.

ECG norm: interpretation of indicators

The diagram of the heart is a continuous line with symbols and marks. Deciphering the cardiogram involves the analysis of this graph, the accuracy of which depends on the accuracy of the diagnosis, and sometimes the life of the patient. Correctly read the ECG can cardiologists, therapists, paramedics. It is technically possible to decode the ECG online.

When analyzing the ECG, the location and size are assessed:

• segments;
• intervals;
• teeth.

For each of them there are strict norms, deviation from which indicates a violation of the functioning of the heart muscle. The doctor should draw conclusions about the pathology, taking into account data from other examinations, as well as the current state of the patient and the conditions under which the ECG was performed. You can not just compare individual parameters in different cardiograms. The evaluation of all indicators is carried out comprehensively.

For an adult, the ECG norm indicators are as follows:

• Heart rate 60-80 beats per minute.
• The heart rhythm is sinus, the norm is characterized by equal PR intervals.
• RR (0.6-1.2 sec) – the interval between the upper points of the ventricles, characterizes the constancy of heart contractions, makes it possible to calculate their frequency.
• PR interval norm 120-200 ms.
• PQ interval norm 120-200 ms.
• ST interval – 320 milliseconds.
• QT interval is normal no more than 420 ms.
• QRS complex norm from 60 to 100-120 ms.
• P-tooth – 80 milliseconds.
• T-tooth – 160 milliseconds.
• J-prong: none.

For patients, an electrocardiogram with a transcript is issued in the form of a conclusion.

ECG abnormalities

ECG is normal if all parameters are within a certain range. Otherwise, they speak of a deviation from the norm, but the doctor must ascertain the presence of pathology. Cardiogram of the heart decoding makes it possible to identify the following pathologies:

• Sinus arrhythmia suggests a physiological disorder, but is normal in children and adolescents.
• Atrial fibrillation may occur intermittently or continuously, accompanied by a feeling in the patient of heart flutter, anxiety, panic
• Sinus bradycardia, when the heart rate is about 50 beats per minute, occurs in healthy people during sleep and in athletes.
• Sinus tachycardia is manifested in excess of the normative heart rate (90 bpm). In healthy people, it is temporarily observed with physical, emotional stress, taking strong coffee, alcohol, energy drinks. The pathology is indicated by a rapid heartbeat at rest.
• Extrasystole is characterized by a chaotic heartbeat, too frequent or too rare. Patients feel thumping behind the sternum, tingling, feeling empty in the stomach or sudden fear.
• Paroxysmal tachycardia manifests itself with periodic palpitations, while the pulse can reach 200-250 beats per minute. The duration of an attack can be from several minutes to several days.
• WPW-syndrome is accompanied by a lack of air, a feeling of cardiac arrest for a moment, a strong heartbeat.

Self-decoding of ECG: algorithm of actions

ECG analysis algorithms summarize practical experience and data taken from special literature. It is especially important to show how ECG decoding is performed for students, interns, paramedics who begin their activities.

Sequence of actions for self-analysis of ECG results:

• Assess the rhythm, its regularity.
• The intensity of contractions of the heart muscle.
• Determine the electrical axis of the heart or the frontal projection of the vector of excitation of the ventricles, the direction of the electric wave through the ventricles during contraction. The electrical axis of the heart is normal from 30° to 70°, the direction is down-right.
• Define P-wave parameters.
• Analyze the QRS complex.
• Define ST segment parameters.
• Analyze T-wave characteristics.
• Analyze the characteristics of the remaining intervals and segments.

How to make an appointment with a cardiologist? Regular customers note the following service benefits:

Patients are advised and accompanied by specialists with a scientific degree, doctors of the highest category with many years of practice.

To make an appointment with a cardiologist, just use the feedback button on the website of the clinic Lorit.

How ECG is deciphered, what indicators matter

Electrocardiography is a minimally invasive and popular way to study cardiac activity. The technique is classified as a screening one, it is prescribed first for any suspicion of heart failure. The patient is urgently sent to do a cardiogram.

This information is obtained by recording and analyzing the electrical potentials produced by the cells of the heart muscle. For professionals, decoding a cardiogram helps to get maximum information about the work of the organ. It is carried out by doctors of functional diagnostics, emergency doctors, cardiologists or therapists.

What are the elements of a cardiogram and what do they mean

The graphic display of heart beats is a broken line. Each of its elements shows the state of the organ, gives a description of the activity of certain parts of the heart. Now in medical institutions, the cardiogram of the heart is made on high-precision cardiographs.

An electrical impulse, propagating along the fibers of the conducting system, forms an excitation wave. It spreads at various intervals in a certain direction, forming Q, R, S waves.

Indicators of the electrical activity of the heart – peaks, teeth, intervals are above, below or on the isoline itself. These parameters are evaluated by the following graphic elements:

1. Prong R. Demonstrates the degree of contraction and relaxation of the atria (left and right).
2. T wave. Reflects myocardial repolarization, shows relaxation of the ventricular myocardium.
3. Wave R. Demonstrates the distribution of impulses through the myocardium of the right and left ventricles. Responsible for their excitement.
4. S wave. Allows you to determine the end of the path that distributes excitations along the interventricular septum.
5. Q wave. Demonstrates the beginning of the distribution of excitation along the septum between the ventricles.
6. Segment (R) ST. Shows the passage of the impulse from the point of the S (R) wave to the beginning of the T wave.
7. P-Q interval (R) – expressed by the distance between the QRS complex and the R wave. It determines the duration of the spread of excitation through the ventricles, the bundle of His, the atrioventricular node, and again to the ventricles.
8. QRST complex – demonstrates the moment of contraction of the muscular layer of the ventricles, which is equal to systole.

When the patient’s ECG is normal, all impulses follow at certain intervals, following a strictly defined sequence.

What data about the work of the heart does the specialist receive when deciphering the ECG

The doctor evaluates the work of the conduction complex of the heart and myocardium on the basis of mathematical and graphical data. Careful ECG decoding reliably reveals the performance of the myocardium, the conduction system of the heart. The main values ​​​​of the cardiogram are normal:

1. Heart rate. Normally, it should be sinus. Rhythm reports from the rhythm of heart contractions, as well as the synchronism of the work of all parts of the heart. It is determined by the teeth R, the distance between them should be the same.
2. Heart rate. The indicator measures the number of heart beats per minute. To do this, the distance between the R waves is multiplied by the speed at which the ECG was recorded. Normally, it is 60-80 beats / minute.
3. Conductivity. Displays impulse transmission. Normally, they are distributed sequentially to each pacemaker, following a certain order.
4. Pacemaker localization. Normally, the sinus node is the pacemaker. From it, impulses diverge through the conduction system of the heart. If it is damaged, the remaining nodes take over this role. This is determined by measuring the P wave.