What is an EKG (Electrocardiogram) and How Is It Used?

What is an EKG?

An EKG or electrocardiogram is a test that checks your heartbeat and your heart’s electrical activity. It uses electrodes (sticky pads) with wires attached to your chest, arms, and legs to record your heart's electrical signals. These signals are plotted on graph paper and look like wavy lines. A doctor can read the EKG tracings to look for abnormal heart activity and problems with electrical conduction.

An EKG test is a quick, painless, and noninvasive test that gives healthcare providers important information about the health of your heart, including:

Blood and oxygen supply to your heart muscle.
Strength and timing of electrical signals passing through each part of your heart.

EKG test results can help in the diagnosis of heart conditions. They can also help your doctors choose the appropriate heart disease treatments for your condition.

Purpose of an EKG in Cardiac Diagnosis

An electrocardiogram (ECG or EKG) can help to diagnose:

Arrhythmias (abnormal heart rhythms such as atrial fibrillation).
Coronary artery disease (blocked or narrowed arteries affecting the blood supply to the heart).
A previous heart attack or silent heart attack.
Enlargement of the heart’s chambers.

EKG vs ECG

There is no difference between ECG vs EKG. Both are the abbreviations for the same test: electrocardiogram. EKG uses German spelling, elektrokardiogramm, while ECG is the English spelling, electrocardiogram. The test is done using several electrodes with adhesive pads attached to the skin of the chest, arms, and legs to measure the heart’s electrical activity.

Electrocardiograph and electrocardiography are terms pertaining to electrocardiogram (ECG/EKG). Electrocardiography is the process of measuring the heart's electrical activity. An electrocardiograph is a device/machine that performs the electrocardiogram to measure heart electrical activity.

An echocardiogram (ECHO) is another similar-sounding diagnostic test; however, this is different from an electrocardiogram (EKG/ECG). It uses high-frequency sound waves to create moving images of the heart. An echocardiogram is done using an ultrasound probe placed on the chest.

A test called the electroencephalogram (EEG) measures brain waves with electrodes placed on the scalp.

Importance of EKG Tests In Heart Health

Common Uses: Why Would Someone Need an EKG Done?

Your healthcare provider may order an EKG if you have symptoms such as:

Chest pain
Dizziness or lightheadedness
Fast or pounding heartbeat
Palpitations
Fluttering or skipping of heartbeats
Shortness of breath
Breathlessness with exercise
Weakness
Fatigue
Confusion

How An EKG Can Assist In Diagnosing Heart Conditions

By measuring the heart’s electrical signal, an electrocardiogram (ECG or EKG) gives your cardiologist (heart specialist or cardiovascular medicine specialist) two pieces of key information:

Heart rate (how fast your heart is beating)
Heart rhythm (whether your heartbeat is regular or irregular)

Family physicians or cardiologists may order an electrocardiogram if they feel your symptoms may be related to heart disease. If you have a diagnosis of heart disease, they may do an EKG to monitor your condition and response to treatment.

An EKG is also done to screen for heart disease in high-risk individuals. For example, a person who does not have any symptoms but has risk factors such as a family history of heart disease.

The American Heart Association and American College of Cardiology also recommend ECG screening in low-risk individuals who don’t have symptoms or risk factors for heart disease. EKG is considered a basic diagnostic tool that is quick, painless, and simple to perform. Talk to your healthcare provider about whether you need to get an EKG as part of routine health exams.

Types of EKG Devices

An electrocardiogram (ECG or EKG) is usually done in an outpatient clinic or hospital emergency room. Outside of healthcare settings, ambulatory electrocardiography can be done using a portable device.

There are several types of EKG testing:

Resting EKG: This is the most common type of ECG test. You lay on your back on a table in a doctor’s office. Electrodes are attached to your chest, arms, and legs. It takes less than 15 minutes to complete this heart test.
Exercise ECG: This is also called a stress test. It measures your heart's activity while you exercise on a treadmill or stationary bike. Your heart rate and blood pressure are also monitored.

In addition, the following EKG devices allow your provider to monitor your heart activity outside of healthcare facilities or doctor's offices:

Holter monitor: This is a portable device that records your heart's activity for 24 to 48 hours while you go about your daily activities. It is also called continuous EKG monitoring.
Event monitor: This device is similar to a Holter monitor, but you wear it for a few weeks or years. You push a button when you feel symptoms and the event monitor records your heart’s activity for a few minutes. Some devices automatically record an irregular heart rhythm. Event monitors are useful if your symptoms are related to irregular heartbeats and tend to come and go. There are different types of event monitors. Below are the two main types:
- Symptoms event monitor: this type of event monitor is available as a hand-held device or worn on the wrist.
- Implantable loop recorder (ILR): This is a type of event monitor where a small device is implanted under the skin of your chest. It monitors your heart's electrical activity for three or more years.
Personal devices: Some smartwatches have an electrocardiogram app that can measure the heart’s electrical activity.

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Preparing For An EKG

Steps To Take Before The Test

There is no special preparation required before an EKG test. You can eat and drink normally. However, if you are having a stress test (exercise EKG test), avoid a heavy meal before the test.

What Should You Avoid Before An EKG?

When getting dressed on the day of your EKG testing, keep the following in mind:

Avoid greasy or oily skin care products (creams and lotions). They can prevent the electrodes from making good contact with your skin.
Wear a top or shirt that can be easily removed. You will need to change into a hospital gown, and some electrodes will be placed on your chest.
Avoid full-length hosiery. Some of the electrodes need to be placed on your legs.

The Procedure of an EKG Test

What Happens During An EKG?

Your healthcare team may ask you to change into a hospital gown before the test. They may shave the areas of the skin where the electrodes will be placed to allow better contact with your skin.

During the EKG test, you will lie flat on your back on an examination table or bed.

If you’re having a standard 12-lead ECG, 12 electrodes (sticky patches with wires attached to them) will be placed at different points on your chest, arms, and legs. The electrodes are connected to an EKG machine and computer that reads your heart beats and your heart’s electrical activity. The results are displayed on a monitor or printed out on graph paper.

EKG is a painless test. You can breathe normally during EKG testing, but you need to remain quiet and still. Movement and talking can interfere with the EKG test results.

How Long Does An EKG Take?

Preparation for an EKG test (getting into a hospital gown and having the electrodes placed) can take 10-15 minutes. The EKG test itself takes only a few seconds.

Interpreting EKG Results

Understanding Normal Versus Abnormal Results

The results of an EKG test are shown as waves on a graph. They represent the electrical signals traveling through different parts of your heart with each heartbeat. There are five waves that are measured - P, Q, R, S, and T.

In an EKG tracing, there are three positive waves above the baseline (P, R, and T) and two negative waves below the baseline (Q and S). Doctors look at various parts of an ECG tracing, such as the P wave, PR interval, QRS complex, QT interval, ST segment, and T wave.

When the heart is healthy and functioning well, it is said to be in sinus rhythm. The amplitude and interval between the ECG waves are constant, indicating a regular heart rate and heart rhythm.

Changes in the EKG waves can give your healthcare professional information about your heart, such as an irregular rhythm, problems with electrical conditions in specific parts of the heart, or poor blood flow in a part of the heart muscle.

What Do EKG Results Tell You?

EKG results tell you about the heart’s electrical impulses and ability to pump blood. They can help your healthcare professional diagnose a heart condition. For example:

Abnormal P waves might indicate atrial enlargement (enlargement of the heart’s upper chambers).
A wide QRS complex may indicate ventricular fibrillation (a type of irregular heartbeat), Wolff-Parkinson-White syndrome (a congenital abnormality with abnormal electrical circuits in the heart), or electrolyte abnormalities such as hyperkalemia (high potassium).
Absent P waves might indicate atrial fibrillation (a type of irregular heart rhythm).
A long QT interval can be a sign of myocardial infarction (heart attack) and other heart problems or a side effect of certain medications.
ST segment depression may indicate ischemia (reduced blood flow to the heart muscle).

Are There Any Risks To The Test?

There are no risks to the EKG test. ECG machines and electrodes do not carry electric current and cannot give you an electric shock. You may have mild skin irritation from the adhesive on the electrode patches.