An electrocardiogram or ECG is a simple type of test that can check the rhythm and electric activity of your heart. ECG uses skin sensors to find electric signals that your heart produces. The test can be done by a healthcare professional that specializes in ECG at a hospital or a clinic, but what exactly does an ECG show? In this article, we’ll be discussing further what the purpose of an ECG is.
What is an electrocardiogram(ECG)?
An ECG(or electrocardiogram) is usually used together with other tests to help diagnose and observe the conditions affecting the heart. It can be used to figure out signs and symptoms of possible heart issues like chest pain, increasing heartbeat, dizziness, and shortness of breath.
A series of ECG tests can also be taken constantly to monitor a patient that has already been diagnosed with a heart condition or taking medication that is known to potentially affect the heart.
What does an ECG show?
An electrocardiogram can detect heart disease and arrhythmias. How they look and develop can help us pinpoint the root cause. If the heart is beating steadily, it produces a typical ECG pattern: the first peak (P wave) shows how an electrical impulse (excitation) travels to the heart’s two atria. The atria contracts, pump blood into the ventricles and then relax immediately. The electrical impulse then reaches the ventricle. This can be seen in the Q, R, and S waves of an ECG called a “QRS complex”. Then the T wave then shows that the electrical impulse stops propagating and the ventricle relaxes again.
What you need to know about an ECG test
An ECG can help detect your heart rate or heart rhythm problems. It can help doctors tell if you have a serious heart condition, or if you’ve experienced having a condition in the past. An ECG is usually one of the first heart tests you will have.
There is no need for special preparation for an ECG test, regular intake of food and drinks is allowed. You will usually need to remove your shirt or any clothing covering your arms and chest, and they might need to get your chest shaved before they attach the electrodes to get more accurate results. Once the skin sensors are in place, you will be offered a hospital gown to cover yourself.
Patches called electrodes will be put on your arms, chest, and legs. These electrodes are connected by wires to an ECG device that can pick up electrical signals that make our hearts beat. It does have some limitations, so you’ll usually have one or more other tests as well. An abnormal ECG reading doesn’t always mean something is wrong with your heart. The test usually only lasts for a few minutes to complete, it is also a harmless, non-invasive test where you will need to lie down still so that the machine can get accurate and stable results.
How do I know if I need an ECG test?
There are many factors that might lead you to think that you may need to take an ECG test. Some of the main signs and symptoms are:
- Dizziness or confusion
- Increasing palpitations
- Shortness of breath
- Fatigue, feeling weak
- Inability to do exercises
- Feeling light-headed or fainting
Types of ECG tests
The type of ECG test you have will be depending on what your signs, symptoms, and possible heart problems are. Let’s say, an exercise ECG might be needed if your symptoms are triggered by any type of physical activity, and you might need to go through an ambulatory ECG if your symptoms happen randomly and unexpectedly. Here are the different types of ECG tests that can be used to measure your heart rate and check for possible causes and underlying conditions.
Resting ECG test
Usually performed while the patient is lying down in a position that’s comfortable for him/her.
Stress or exercise ECG test
This type of ECG is conducted when the patient is using a piece of exercise equipment such as treadmills or an exercise bike.
Cardiac event recorder
If your symptoms are uncommon or unusual, your doctor may recommend a cardiac event recorder or implantable loop recorder(ILR). In a minor surgery under local anaesthesia, an implantable loop recorder will be implanted under the skin of your chest. This is especially useful for people whose symptoms are not or can not be detected by a standard ECG or Holter monitor. The ILR can continuously monitor your heartbeat for up to three years and help determine what may be causing your symptoms such as dizziness or fainting.
Ambulatory ECG test or 24-hour ECG recording
Also called a Holter monitor, this type of ECG has electrodes linked to a portable machine that’s usually placed on the patient’s waist to constantly monitor his/her heart rate at home for more than a day.
When undergoing a 24-hour ECG recording test, you will experience the following scenarios:
- There will be three electrodes placed on the chest, and the wires that connect to these electrodes will be taped to prevent unnecessary movements.
- You’ll be wearing a small portable recorder on a belt, where the wires are connected to.
- When you wear an ECG during the recording, you can do everything you would normally do(working, going outside, etc.) except taking a bath or shower.
- It is safe, completely painless, and harmless for everyone.
- After the test is complete, you will be returning the ECG recorder to the hospital so the results can be observed and analyzed.
An ECG is a safe procedure. Since the electrodes being used do not generate electricity, there is no risk of any type of electric shock during the test. The electrodes keep track of the electrical activities and movements of the heart. An ECG test does have some limitations, so you’ll usually have one or more other tests as well. An abnormal EKG reading doesn’t always mean something is wrong with your heart. If symptoms happen only from time to time, they might be difficult to detect during standard ECG recordings and it might be a more serious condition than you think. Always seek advice and consult with your doctor if you need an ECG test.