Electrocardiogram (ECG) Test

ByJanis Updated

Overview

An electrocardiogram (ECG or EKG) records the heart’s electrical activity. This simple test can help detect heart conditions like arrhythmias or heart attacks. Many places have ECG machines, including:

  • Hospitals
  • Medical offices
  • Operating rooms
  • Ambulances

Some smartwatches and personal devices also offer basic ECG features. People interested in these options should talk with a healthcare professional.

Main Types of Heart Electrical Tests

  • Holter monitor checks heartbeats for 24–48 hours.
  • Implantable loop recorder tracks rhythms over months.
  • 12-lead EKG records heart’s signals from many angles.
  • Computerized EKG technologies help with faster analysis.
  • Stress tests measure how the heart works during exercise.
  • Echocardiograms create real-time images of the heart.
  • Thallium scans use a small amount of radioactive material to view blood flow.

Reasons for Using an Electrocardiogram

Doctors use an electrocardiogram (ECG or EKG) to check how the heart is functioning. This simple test shows the rate and rhythm of the heartbeat and provides important details about the heart’s health to help guide care decisions.

Doctors often order ECGs when someone reports chest pain, feels dizzy, notices a pounding or irregular heartbeat, has a rapid pulse, or feels tired more easily than usual. Sometimes, a person with no clear symptoms but a family history of heart problems also needs this test for screening.

Extra Details and How to Learn More

When Doctors May Suggest an ECG

Doctors may order an ECG in the following cases:

  • Symptoms Pointing to Heart Problems:
    • Chest pain
    • Fainting, dizziness, or confusion
    • Feeling like the heart is skipping beats or beating too fast
    • Trouble catching breath
    • Weakness or trouble exercising
  • To Check for Certain Health Problems:
    • Irregular heart rhythm (arrhythmias)
    • Past heart attack
    • Signs of blocked heart arteries
    • Problems with heart valves
    • Issues with an implanted device, such as a pacemaker
  • For People with Higher Risk:
    • Family history of heart disease
    • Other risk factors, like high blood pressure or diabetes

How ECGs Help With Diagnosis

The ECG shows electric activity in the heart. By looking at the results, a doctor can:

  • Find if the heart beats too slow, too fast, or in an unusual way.
  • See any signs that may point to a past heart attack or one happening now.
  • Check if the heart’s chambers look bigger than normal.
  • Pick up changes that might signal blocked or tight arteries.
Common Heart Problems Found With ECGs
Problem What It Means
Arrhythmia Irregular or extra heartbeats
Heart attack Heart muscle damage from blocked arteries
Coronary artery disease Arteries supplying the heart are narrowed
Cardiomyopathy Heart muscle is weak or thickened
Heart valve disorders Problems with valves opening or closing

Different Types of Heart Rhythm Tests

Sometimes, regular ECGs do not catch every issue, especially if symptoms come and go. In these cases, healthcare providers use portable monitors:

  • Holter Monitor: Patients wear this for 24 hours or longer, and it records the heartbeat all day during daily activities.

  • Event Monitor: Patients use this for up to a month, and it records only during certain times, usually when symptoms appear.

  • Personal Devices: Some smartwatches can check heart rhythm. Ask a healthcare provider if these are right for you.

Health Problems Checked by ECG

ECGs can help spot many different conditions, such as:

  • Atrial fibrillation (irregular, fast heartbeat)
  • Myocardial ischemia (blood flow blockage in the heart)
  • Heart valve issues (like stenosis or regurgitation)
  • Congenital heart defects
  • Pericarditis (inflammation of the heart’s lining)
  • Ventricular tachycardia (dangerously fast heart rhythm)
  • Heart enlargement
  • Bradycardia (slow heartbeat)
  • Sudden cardiac arrest risk

Potential Issues

The electrocardiogram (ECG) is a very safe test with no danger of electric shock, since the electrodes only collect signals and do not give off electricity. Mild side effects include a small risk of skin irritation, redness, or discomfort where the patches are placed and removed, much like taking off a sticky bandage.

These effects are not related to any heart disease, chest pain, cardiomyopathies, or arrhythmias, and the test does not cause heart damage or trigger heart attack symptoms.

How You Get Ready

In most cases, no special preparation is required before an electrocardiogram (ECG). However, to ensure accurate results, consider the following steps:

  • Remove any jewelry that might interfere with the electrode placement.
  • Inform your healthcare provider about all medications you’re taking, including prescription drugs, over-the-counter medicines, and dietary supplements.

Some medications can affect your ECG results, so providing a complete list is important. Your medical team may ask about your medications before the test.

What You Can Expect

Healthcare staff often ask patients to change into a gown first. Sometimes, the team may trim hair where the electrode patches will go, such as on the chest, to help the electrodes stick to the skin properly. Patients usually lie down on a medical table for the test.

While the Test is Happening

  • Healthcare providers attach up to 12 small, sticky electrodes to the skin on the chest, and sometimes the arms or legs.
  • Wires from the electrodes connect to a computer, which displays the heart’s electrical signals as wavy lines.
  • Patients should lie still, breathe normally, and avoid talking because movement can impact the results.
  • Healthcare staff may take blood pressure along with the test, depending on the reason for the visit.
  • The test is painless and takes only a few minutes. Sometimes, a doctor reviews the results instantly.

Once the Test is Finished

Most people can get dressed and return to their usual activities right away since this is usually an outpatient procedure. If there is no urgent heart issue, patients do not need special care after the test.

Results

An EKG tracing displays the heart’s electrical activity using a series of waves and intervals. Healthcare professionals use these results to analyze both the function and structure of the heart. The key elements they examine include heart rate, rhythm, and specific features of the waveforms:

EKG Feature What It Shows Possible Medical Condition
P Wave Atrial activity Atrial rhythm disturbances
QRS Complex Ventricular contraction Ventricular hypertrophy, block
ST Segment Early ventricular recovery Ischemia, injury
T Wave Ventricular repolarization Ischemia, electrolyte issues
Rhythm Regularity between beats Arrhythmias like AFib
Rate Number of beats per minute Tachycardia, bradycardia
  • P Wave: This part of the EKG shows the electrical activity as the atria contract.
  • QRS Complex: This represents electrical signals moving through the ventricles and shows if the ventricles are contracting correctly.
  • ST Segment and T Wave: These sections provide details about the recovery phase of the heart muscle and can help identify ischemia or previous heart injury.
  • Heart Rate: The EKG helps determine if the heart is beating too fast (tachycardia) or too slow (bradycardia).
  • Heart Rhythm: Results can show whether the heartbeat pattern is regular or if there are rhythm disturbances like atrial fibrillation or other arrhythmias.
  • Additional Signs: Changes in the size or pattern of waves may point to ventricular hypertrophy, congenital issues, or effects from drugs.

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Health Writer

Janis's areas of expertise include nutrition, exercise, stress management, and mental health. She is passionate about educating and empowering people to take control of their health and make positive changes that can last a lifetime. Janis believes that small, sustainable changes are the key to long-term success, and she works with her clients to develop personalized plans that fit their individual needs and lifestyles.