What is an EKG (electrocardiogram)?

An EKG (electrocardiogram, or ECG) is a painless test that records the electrical activity of your heart. An EKG helps your doctor diagnose and monitor many heart problems. These commonly include a heart attack, cardiac arrhythmias (abnormal heartbeats), and coronary artery disease (narrowing of the coronary arteries). 

An EKG is a safe, routine procedure. It is only one method to monitor and diagnose heart conditions. Discuss all of your testing options with your doctor or healthcare provider to understand which options are right for you.  

Types of EKG 

The types of EKG include:

  • Standard (resting) EKG involves measuring your heart’s electrical activity as you relax in a reclining or semi-reclining position. This is the most common type of EKG. 
  • Stress test (exercise EKG or treadmill test) involves performing an EKG while you exercise, usually on a treadmill. It shows how exercise affects your heart. It helps to diagnose and assess coronary artery disease and other types of heart disease. Sometimes medication is given instead to mimic exercise’s effect on the heart.
  • Holter monitor (24-hour EKG or ambulatory EKG) involves wearing an electronic EKG recorder for 24 hours. It records the electrical activity of your heart over 24 hours. It helps diagnose arrhythmias (irregular or abnormal heartbeats).
  • Cardiac event recorders record an EKG over a longer period of time, up to a year or longer. Portable cardiac event recorders record the heart’s electrical activity when you get symptoms. Implantable loop recorders are implanted under the skin in your chest. They record your heart’s electrical activity continuously. 

Why is an EKG (electrocardiogram) performed? 

Your doctor may recommend an EKG to help evaluate your heart health. It is a routine part of checkups, especially for people over the age of 40. 

An EKG by itself cannot diagnose all types of heart conditions or predict future heart problems. It provides important information about your heart health in relation to your age, physical exam, medical history, and other tests. 

Doctors use EKGs to help diagnose, determine the severity of, or monitor treatment of the following conditions:

  • Cardiac arrhythmias including heartbeats that are too fast, too slow, or irregular. Doctors also use EKGs to check how a pacemaker is functioning. 
  • Cardiomyopathy, thickened or enlarged heart muscle 
  • Congenital heart defects, birth defects of the heart 
  • Coronary artery disease (CAD), a buildup of plaque on the walls of the coronary arteries. These arteries supply blood to the heart.
  • Heart attack, death of a portion of the heart muscle. A heart attack is usually due to coronary artery disease and a blood clot that blocks blood flow to the heart.
  • Heart failure, a weakened heart that cannot pump enough blood to the body
  • Heart murmurs, unusual or abnormal heart sounds heard with a stethoscope
  • Heart valve disease including narrowed valves and leaky valves 
  • Pericarditis, inflammation of the sac that surrounds the heart 

Your doctor may also perform an EKG to check your heart’s health before surgery. An EKG can also help your doctor determine if some symptoms are related to a heart problem. Symptoms include chest pain, dizziness, shortness of breath, fatigue, weakness, palpitations, passing out, or feeling a pounding, racing or irregular heartbeat.

Who performs an EKG (electrocardiogram)?

A doctor, nurse or technician performs an EKG. Your doctor may look at the test right away, but a cardiologist will provide the final results to your doctor. Doctors who order EKGs include:

  • Cardiac surgeons specialize in the surgical treatment of conditions of the heart and its blood vessels. Cardiac surgeons may also be known as cardiothoracic surgeons. 
  • Cardiologists and pediatric cardiologists are internists or pediatricians who specialize in diagnosing and treating diseases or conditions of the heart and its blood vessels.
  • Emergency medicine doctors specialize in the diagnosis and treatment of sudden illness or injury and complications of chronic diseases.
  • Interventional cardiologists are cardiologists who specialize in diagnosing and treating conditions and diseases of the heart and its blood vessels. They use nonsurgical, catheter-based procedures and imaging techniques.
  • Primary care providers including internists, family practitioners (family medicine doctors), pediatricians, geriatricians, physician assistants (PAs), and nurse practitioners (NPs). Primary care providers offer comprehensive healthcare services and treat a wide range of illnesses and conditions. 
  • Thoracic surgeons specialize in the surgical treatment of diseases of the chest, including the blood vessels, heart, lungs and esophagus. Thoracic surgeons may also be known as cardiothoracic surgeons.