An ECG (electrocardiogram) is a painless diagnostic test completed in a short time that records the electrical activity of the heart via electrodes placed on the skin. An electrocardiogram provides information about heart rate, heart rhythm, and electrical conduction. It is one of the essential tests used particularly in the evaluation of rhythm disorders and suspected heart attacks.
During an ECG procedure, electrodes are placed on the chest, arms, and legs. The recording is usually completed within a few minutes. ECG results are evaluated by the physician along with the individual's symptoms and other tests. A normal ECG result does not rule out all heart diseases.
What is an ECG Used For?
An ECG provides information about the regularity and rate of heartbeats and the electrical conduction system by recording the electrical activity of the heart. The obtained records help evaluate the functioning pattern of the heart and determine findings related to certain heart diseases.
The main information that can be evaluated with an ECG includes:
- Heart rate: Determines how many times the heart beats in one minute.
- Heart rhythm: Examines whether the heartbeats are regular or irregular.
- Electrical conduction: Evaluates the conduction process of electrical impulses within the heart.
- Changes related to the heart muscle: Findings that may be associated with problems in the oxygenation of the heart muscle or previous cardiac damage can be examined.
An ECG shows the electrical activities of the heart. It does not directly image the anatomical structure of the heart or the interior of the vessels.
Why is an ECG Performed?
An ECG may be performed to evaluate complaints related to heart rhythm, to suspect heart diseases, or to monitor an existing cardiac condition. In some cases, it may also be requested as part of pre-operative evaluations.
The main conditions that may require an ECG include:
- Palpitations: The sensation that the heart is beating rapidly, irregularly, or differently than normal.
- Chest pain: Evaluation of chest pain and a feeling of pressure that may be of cardiac origin.
- Shortness of breath: Investigation of causes that may be related to the heart.
- Dizziness and fainting: Examination of changes that may be associated with heart rhythm.
- Heart disease monitoring: Evaluation of known heart diseases or the effects of certain medications on the electrical activity of the heart.
The necessity of performing an ECG is determined by the physician based on the individual's complaints and the results of the clinical evaluation.
How is an ECG Performed?
During an ECG procedure, the patient generally lies on their back. The electrical signals of the heart are recorded via electrodes placed on their chest, arms, and legs. These signals are displayed as waveforms on the device screen or on paper.
The main stages of an ECG procedure are as follows:
|
Stage |
Application |
|
Preparation |
The patient lies down in the proper position and the areas where the electrodes will be placed are prepared. |
|
Placement of Electrodes |
Electrodes are placed on the chest, arms, and legs. |
|
Recording |
The electrical activity of the heart is recorded while the patient remains still. |
|
Evaluation |
The ECG recording is examined by the physician. |
It is important for the patient to remain still and not speak during the procedure to ensure the recording is taken accurately.
What Should Be Considered Before an ECG?
No special preparation is generally required for a resting ECG. However, certain points that may affect the recording quality should be taken into consideration.
- It is recommended not to apply creams, lotions, or oily products to the chest area.
- Clothing that is easily removable or facilitates access to the chest area can be preferred.
- Regularly used medications and existing health problems should be reported to the healthcare personnel.
- One should remain as still and in a comfortable position as possible during the procedure.
Medications being used should not be discontinued without a physician's recommendation.
How Many Minutes Does an ECG Take?
In a standard resting ECG, the recording of electrical activity usually takes a few seconds. Together with the placement of electrodes and the preparation stages, the procedure is mostly completed within a few minutes.
The duration may be extended if a repeat recording or additional evaluation is required.
Which Diseases Are Revealed on an ECG?
An ECG is a diagnostic test that helps determine electrical changes related to certain heart diseases. It is particularly used in the evaluation of rhythm and conduction disorders. However, not every heart disease may manifest symptoms on an ECG.
The main conditions that can be detected or suspected on an ECG include:
- Heart rhythm disorders (arrhythmias): Conditions where the heart beats faster, slower, or irregularly than normal, such as atrial fibrillation and certain types of tachycardia and bradycardia.
- Heart attack (myocardial infarction): ST-segment and other ECG changes that can be observed in certain heart attacks.
- Oxygenation problems in the heart muscle (ischemia): Electrical changes that may be associated with insufficient blood reaching the heart muscle.
- Electrical conduction disorders of the heart: Conditions affecting the transmission of electrical impulses, such as atrioventricular block and bundle branch block.
- Enlargement of the heart chambers or thickening of the heart muscle: ECG findings that may suggest these changes in certain cases.
- Electrolyte imbalances: ECG findings that may be associated with certain changes, particularly in potassium and calcium levels.
- Inflammation of the heart lining (pericarditis): Characteristic electrical changes that can be observed in some patients.
Not all of these findings alone mean a definitive diagnosis. For example, observing a finding suggesting thickening of the heart muscle on an ECG does not definitively indicate that this condition is present.
In the evaluation of heart diseases, ECG findings are interpreted in conjunction with physical examination, blood tests, echocardiography, and other examinations deemed necessary.
How Are ECG Results Interpreted?
ECG results are interpreted by examining the waves showing the electrical activity of the heart and the intervals between these waves. The physician evaluates the heart rate, the regularity of the rhythm, electrical conduction times, and changes that may be related to the heart muscle.
The main sections examined in an ECG recording are:
- P wave: Shows the electrical activation of the atria, which are the upper chambers of the heart.
- QRS complex: Shows the electrical activation of the ventricles, which are the lower chambers of the heart.
- T wave: Reflects the electrical recovery process of the ventricles.
- PR, QRS, and QT intervals: Provide information about the transmission of electrical impulses and the timing of the electrical activity of the heart muscle.
- ST segment: A section that may change in certain heart diseases and is evaluated particularly regarding the oxygenation of the heart muscle.
Automatic interpretation may be available on ECG devices. However, the preliminary evaluation generated by the device does not replace the physician's interpretation.
What Are Normal ECG Values?
A normal ECG contains findings indicating that the heart rhythm and electrical conduction are appropriate for the individual's age and clinical characteristics. In healthy adults at rest, the heart rhythm is generally regular, and the heart rate is mostly between 60–100 beats per minute.
Some of the baseline values used in ECG evaluation are as follows:
|
ECG Parameter |
General Reference in Adults |
|
Heart rate |
Generally 60–100 beats/minute at rest |
|
Heart rhythm |
Regular sinus rhythm |
|
PR interval |
Generally 120–200 milliseconds |
|
QRS duration |
Generally under 120 milliseconds |
|
QT/QTc interval |
Evaluated along with heart rate, age, gender, and other clinical characteristics |
These values are for general informational purposes. Expected values may vary, particularly in children, athletes, individuals using certain medications, and specific health conditions.
For example, a resting heart rate below 60 beats per minute in individuals who exercise regularly does not always mean a disease.
A normal ECG result may indicate that no significant electrical abnormality was observed during the recording. However, having a normal ECG result does not mean that all heart diseases have been ruled out.
What Does an Abnormal ECG Result Mean?
An abnormal ECG result means that a finding outside the expected pattern has been detected in the electrical activity of the heart. This condition may be related to changes in heart rate, rhythm, conduction times, or the shape of the ECG waves.
Possible causes of abnormal ECG findings include:
- The heart rhythm being faster or slower than normal
- Irregularity of heartbeats
- Presence of a delay or disorder in the electrical conduction of the heart
- Changes related to the oxygenation of the heart muscle
- Differences in electrolyte levels
- Certain medications affecting the electrical activity of the heart
However, not every abnormal ECG result indicates a serious heart disease. Some findings may be related to personal differences, temporary physiological changes, or technical effects occurring during the recording.
When an abnormal result is obtained, the physician may request the ECG to be repeated or additional tests to be performed by evaluating the individual's complaints and medical history.
What Are the Types of ECG?
An ECG can be applied using various methods to evaluate the electrical activity of the heart under different conditions. The method to be used is determined based on the patient's complaints and the health problem being investigated.
Resting ECG
A resting ECG is the recording of the heart's electrical activity while the individual is in a resting state. A short-term recording is usually taken.
It is the primary ECG method used in evaluations regarding heart rhythm, heart rate, and electrical conduction.
Exercise ECG (Stress Test)
An exercise ECG is a test in which the electrical activity of the heart is monitored during physical exertion. The patient typically walks on a treadmill or uses a stationary bicycle.
During the test, heart rhythm, heart rate, blood pressure, and the patient's complaints are monitored. It can be used to evaluate the heart's response to exercise.
An exercise ECG may not be suitable for every patient. The necessity and applicability of the test are evaluated by the physician.
Holter ECG
A Holter ECG is a method that allows the electrical activity of the heart to be monitored during daily life using a portable recording device.
The recording duration may vary depending on the device used and clinical need. Recordings of 24–48 hours or longer can generally be made.
It can be used particularly in evaluating occasionally occurring palpitations, irregular heartbeats, and certain fainting complaints.
What is the Difference Between ECG and ECHO?
ECG and ECHO (echocardiography) are two separate diagnostic methods used to evaluate different characteristics of the heart.
While an ECG records the electrical activity of the heart, an ECHO provides imaging of the heart's structure and movements using ultrasound waves.
|
Feature |
ECG |
ECHO |
|
Primary method |
Recording of electrical activity |
Imaging with ultrasound |
|
What is evaluated? |
Heart rhythm, rate, and electrical conduction |
Heart chambers, valves, and heart muscle movements |
|
How is it applied? |
Electrodes are placed on the skin |
Imaging is performed with an ultrasound probe |
|
Primary purpose of use |
Examination of findings related to electrical activity |
Evaluation of anatomical and functional features of the heart |
ECG and ECHO are not interchangeable tests. Both examinations can be utilized together when deemed necessary.
Is an ECG Procedure Risky?
A standard resting ECG is a non-invasive examination generally considered safe. No electricity is delivered to the body during the procedure; only the electrical signals naturally generated by the heart are recorded.
Mild skin irritation in the areas where the electrodes are placed or a brief discomfort when removing the electrodes may be observed.
An exercise ECG, on the other hand, may carry different risks compared to a resting ECG because it involves physical exercise. Therefore, the patient's suitability is evaluated, and the test is performed under the supervision of healthcare personnel.
Which Department Should Be Visited for an ECG?
An ECG is a frequently used test in evaluating complaints related to the heart. It may be requested by the Cardiology Department for evaluations regarding suspected heart rhythm disorders, palpitations, and other heart diseases.
An ECG can also be applied in emergency departments and different clinical units when deemed necessary.
If there are symptoms that may be associated with a heart attack, such as pressure or pain in the chest, significant shortness of breath, cold sweating, or fainting, emergency assistance should be sought through the 112 Emergency Call Center rather than waiting for a routine outpatient clinic evaluation.
