What’s an EKG?

EKG (or ECG) stands for electrocardiogram: a picture of the electrical signal of your heart. It’s a fast and painless test that gives an expert information about the activity of your heart. The machine used for an EKG is an EKG machine or ECG machine. It doesn’t send electricity into your body or create any risk for you.

10 or 12 electrodes will be attached to your chest, arms, and legs. The EKG machine prints out a graph showing the activity of your heart. It might also store the information electronically. 

What does an EKG measure?

During each heartbeat, your heart shows some predictable activity. The electrical changes create a typical pattern that may be familiar to you:


Different patterns show atypical behavior on the part of the heart. 

Some of the things an EKG can show:

  • the rate (speed) of heartbeats
  • the rhythm of heartbeats
  • the size and position of the heart’s chambers
  • damage to the heart
  • evidence of a heart attack
  • blood flow to the heart
  • a heart murmur or other abnormality

 How to prepare for the exam

You might need an EKG if there is some question about how well your heart is functioning. This type of test can be used to determine whether you are having a heart attack, or to identify problems with your heart.

You do not need to make any preparations for this exam, but you will need to have electrodes taped to your skin, so you should wear clothes that provide access to your chest and your limbs, or you may have to undress. You might need to have your chest hair shaved in order to get a good connection. 

Some types of heart monitors provide electrical measurements over time. You would still have electrodes applied, but you will wear them home and go about your usual activities (except showers) while they measure your heart activity. Again, this does not require any special preparation.