What is an electrocardiogram?

An electrocardiogram (ECG or EKG) records the electrical signals in the heart. It's a common and painless test used to quickly detect heart problems and monitor the heart's condition.

An electrocardiogram is one of the simplest and fastest tests used to evaluate the heart. Electrodes (small, plastic patches that stick to the skin) are placed at certain spots on the chest, arms, and legs. The electrodes are connected to an ECG machine by lead wires. The electrical activity of the heart is then measured, interpreted, and printed out. No electricity is sent into the body.

Natural electrical impulses coordinate contractions of the different parts of the heart to keep blood flowing the way it should. An ECG records these impulses to show how fast the heart is beating, the rhythm of the heart beats (steady or irregular), and the timing of the electrical impulses as they move through the different parts of the heart. Changes in an ECG can be a sign of many heart-related conditions.


Some reasons a provider may request an ECG include:

  1. To look for the cause of chest pain
  2. To evaluate problems that may be heart-related, such as severe tiredness (fatigue), shortness of breath, dizziness, or fainting
  3. To identify irregular heartbeats
  4. To help assess the overall health of the heart before procedures, such as surgery; after treatment for a heart attack (myocardial infarction), endocarditis (inflammation or infection of one or more of the heart valves), or other condition; or after heart surgery or cardiac catheterization
  5. To see how an implanted pacemaker is working
  6. To find out how well certain heart medicines are working
  7. To get a baseline tracing of the heart's function during a physical exam, which can be compared with future ECGs

Diagnostic Testing