What is electrocardiography?
Electrocardiography (EKG) is a quick, simple, and painless procedure in which the heart’s electrical impulses are amplified and recorded. This record provides information about the electrocardiogram (also known as ECG).
- Part of the heart that activates each beat (the pacemaker, called the sinoatrial or sinus node)
- Nerve conduction pathways of the heart
- Heart rate and rhythm
Sometimes the electrocardiogram (ECG or EKG) can show that the heart is enlarged (usually due to high blood pressure) or that the heart is not getting enough oxygen due to a blockage in one of the blood vessels supplying the heart (the coronary arteries).
An ECG is usually obtained if a heart disorder is suspected. It is also sometimes obtained as part of a routine physical exam for middle-aged and older people, even if they have no evidence of a heart disorder. It can be used as a basis for comparison with subsequent ECGs if a heart disorder develops.
Abnormal heart rhythms and inadequate blood flow to the heart muscle can occur only briefly or unpredictably. To detect such problems, doctors can use a continuous ambulatory electrocardiogram, in which the ECG is recorded while the person goes about normal daily activities.
How the electrocardiogram is performed
To obtain an ECG, an examiner spaced electrodes (small round sensors that stick to the skin) on the person’s arms, legs, and chest. These electrodes do not contain needles and are painless. If there is thick hair, the areas to which the electrodes are applied can be shaved first. These electrodes measure the magnitude and direction of electrical currents in the heart during each beat. The electrodes are connected by wires to a machine, which produces a record (trace) for each electrode. Each trace shows the electrical activity of the heart from different angles. The traces make up the ECG. The ECG takes about 3 minutes and is safe.
Types of ECGs
- Holter monitor
- Implantable loop recorder
Why electrocardiogram is for?
An ECG is a painless, non-invasive way to help diagnose many mutual heart problems in people of all ages. Your doctor may use an ECG to determine or detect:
- Abnormal heart rhythm (arrhythmias)
- If blocked or tapering arteries in your heart (coronary artery disease) are causing chest pain or a heart attack
- If you have had a previous heart attack
- How well certain heart disease treatments are working, such as a pacemaker
You may need an ECG if you have any of the following signs and symptoms:
- Chest pain
- Dizziness, lightheadedness, or confusion
- Heart palpitations
- Rapid pulse
- Difficulty breathing
- Weakness, fatigue, or decreased ability to exercise.
The American Heart Association does not recommend the use of ECGs to evaluate low-risk adults who do not have symptoms. But if you have a family history of heart disease, your doctor may suggest an ECG as a screening test, even if you don’t have symptoms.
If your symptoms incline to come and go, they may not be captured during a standard ECG recording. In this case, your physician may recommend remote or continuous ECG monitoring. There are several different types.
Holter monitor: A Holter monitor is a small, portable device that records a continuous ECG, usually for 24 to 48 hours.
Event monitor: This portable device is similar to a Holter monitor but records only at certain times for a few minutes at a time. You can wear it for longer than a Holter monitor, usually 30 days. You usually press a button when you feel symptoms. Some devices are automatically best when an abnormal rhythm is detected.
Did the electrocardiogram hurt?
No. There is no pain or risk associated with having an ECG. When the ECG stickers are removed, there may be a little discomfort.
Is the electrocardiogram painful?
No. The machine only records the ECG. It does not send electricity to the body.
The ECG is indicated if there is suspicion of:
- Heat illness: Myocardial infarction, arrhythmias, conduction disturbances, and myocardial ischemia
- Metabolic disease: Hypocalcemia and hypokalemia
- Endocrine disease: Illnesses of the thyroid gland (hypothyroidism and hyperthyroidism).
How should I prepare for an electrocardiogram?
Some things you can do to prepare:
- Avoid oily skin creams and lotions on the day of the test because they can prevent the electrodes from coming into contact with your skin.
- Avoid long stockings, because the electrodes must be placed directly on the legs.
- Wear a shirt that can be easily removed to place the wires on your chest.
What happens during an electrocardiogram?
A technician will place 10 electrodes with sticky pads on the skin of your chest, arms, and legs. If you are a man, you may need to shave your chest hair to allow for a better connection. During the test, you will lie depressed while a computer creates a picture, on graph paper, of the electrical impulses moving through your heart. This is called a “resting” EKG, although the same test can be used to monitor your heart while you exercise.
It takes approximately 10 minutes to place the electrodes and complete the test, but the actual recording only takes a few seconds. Your doctor will keep your ECG patterns on file so that they can be compared with future tests.
Why might I need an electrocardiogram?
Some reasons for your doctor to order an electrocardiogram (ECG) include:
- To find the cause of chest pain
- To evaluate problems that may be related to the heart, such as severe tiredness, shortness of breath, dizziness, or fainting.
- To identify an irregular heartbeat
- To help determine your overall heart health before procedures such as surgery; or after treatment for conditions such as a heart attack (myocardial infarction or MI), endocarditis (inflammation or infection of one or extra of the heart valves); or after heart surgery or cardiac catheterization.
- To see how an implanted pacemaker is working
- To find out how well certain heart medications are working
- To get a baseline follow-up of heart function during a physical exam. This can be used as a comparison with future ECGs, to determine if there have been any changes.
There may be other details for your doctor to recommend an ECG
What are the risks of an EKG?
An electrocardiogram (ECG) is a quick and easy way to assess heart function. The risks associated with the ECG are minimal and rare. You won’t feel whatever during the ECG, but it may feel uncomfortable when the sticky electrodes are removed. If the electrode patches are left on too long, they can cause tissue breakage or skin irritation.
There may be other risks contingent on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the test. Certain factors or conditions can interfere with or affect the ECG results. These include, but are not limited to:
- The pregnancy
- Accumulation of fluid in the abdomen (ascites)
- Anatomical considerations, such as the size of the chest and the location of the heart within the chest
- Movement during the test
- Exercising or smoking before the test
- Certain medications
- Electrolyte imbalances, such as too ample or too little potassium, magnesium, or calcium in the blood