A Guide to Electrocardiogram (EKG) Testing: What to Expect

If you’re scheduled to have an electrocardiogram (EKG), you may wonder what to expect. Here, we break down what you need to know about an EKG test, including:

• What is an EKG?

• What does an EKG show? 

• How is an EKG performed?

• The different types of EKGs

• Do you need to prep for an EKG test?

• What do the test results mean?

• What are the limitations of an EKG?

An electrocardiogram, commonly known as an EKG or ECG, is a test that measures the electrical activity of your heart. It’s a quick, painless, noninvasive test used to check for various heart conditions. By tracking the electrical signals of your heart, an EKG provides valuable information about how your heart is functioning.

An EKG can reveal a lot about your heart's health, such as the following.

• Heart rate: It shows how fast or slow your heart is beating.

• Heart rhythm: It helps identify irregular heartbeats, known as arrhythmias.

• Heart attack: It can indicate if you’ve had a heart attack in the past or if you're currently experiencing one.

• Heart structure: It can show if parts of your heart are overworked or enlarged.

• Blood flow: It can suggest if there's reduced blood flow to parts of the heart muscle.

The test is quick and simple and usually takes less than 10 minutes. Here’s what happens during the procedure.

• Electrode placement: Small sticky patches called electrodes are placed on your chest, arms and legs. These electrodes are connected to wires that lead to the EKG machine.

• Recording: You’ll lie still while the machine records the electrical signals from your heart. You don’t feel anything during this process.

• Completion: Once the recording is done, the electrodes are removed, and you can get dressed.

The whole process is painless, and you can resume your normal activities right after the test.

EKGs come in various forms to cater to different diagnostic needs and patient situations. Here’s a breakdown of the different types of EKGs.

• Resting EKG: This is the most common type of EKG, and the type described above. 

• Stress EKG (exercise EKG): This EKG is performed while the patient exercises on a treadmill or stationary bike. It measures the heart's activity under physical stress.

• Holter monitor: A Holter monitor is a portable device that records the heart's activity continuously, essentially wearing a portable EKG over 24 to 48 hours or longer. 

• Extended event monitor: Similar to a Holter monitor, this is an event monitor that can be worn for weeks or even months and is often smaller and more compact. 

• Telemetry monitor: Telemetry monitoring involves continuous EKG monitoring in a hospital setting, typically for patients who need constant surveillance due to acute heart conditions.

• Implantable loop recorder (ILR): An ILR is a small device implanted under the skin of the chest to monitor heart activity for up to three years.

There is almost no preparation needed for an EKG test. However, there are a few simple reminders to note.

• Dress comfortably: Wear a loose shirt that can be easily removed or rolled up. You will need to undress from the waist up for the test.

• Avoid lotions and oils: On the day of the test, skip lotions, oils or powders on your chest, as they can prevent the electrode stickers from sticking properly.

• Inform your doctor: Let your doctor know about any medications or supplements you are taking, as some may affect heart activity.

The results of your EKG will show the pattern of your heart's electrical activity. 

• Normal results, also known as “normal sinus rhythm:” Your heart is functioning normally with a steady rhythm and appropriate rate.

• Abnormal results: These may indicate various issues like arrhythmias, heart attacks (current or past), enlarged heart chambers or insufficient blood flow. 

The EKG machine has a built-in algorithm that can recognize basic patterns on an EKG. However, EKG interpretation can be difficult at times, and your doctor will need to interpret these results and may recommend further tests if needed. If you are ever unsure of the automatic readings on an EKG, please consult your doctor. 

As a cardiology fellow at Montefiore Medical Center, I know that while an EKG is a valuable tool, it has several limitations.

• Temporary issues: An EKG captures your heart activity at one moment in time. If your symptoms are intermittent, they might not show up on the test.

• Non-specific results: Sometimes, abnormal results might not point to a specific condition and could require additional tests to pinpoint the problem.

• False alarms: Occasionally, an EKG might indicate an issue that isn't actually there, leading to unnecessary worry or further testing.

• Limited scope: An EKG can’t provide detailed images of the heart, so it may miss structural issues that other tests like echocardiogram or magnetic resonance imaging (MRI) can detect.

An EKG is a simple, quick and noninvasive test that provides important information about your heart’s electrical activity. While it’s a powerful diagnostic tool, it’s important to understand its limitations and that sometimes further tests may be needed to get a complete picture of your heart health. Always discuss your results and any concerns with your doctor to ensure you get the most accurate diagnosis and appropriate care.

For more information on cardiovascular diseases, check out these additional resources:

Pulmonary Embolism: What It Is, Risk Factors, Symptoms, Types & Treatment

What Is a Heart Attack and What Are the Symptoms?

What to Know About the Different Types of Bradycardia

The Bradycardia Symptoms Everyone Should Know