An electrocardiogram, also called EKG or ECG, gives physicians specific information about the electrical activity of the heart by recording its rhythms and patterns. An electrocardiogram helps to diagnose heart conditions. During an emergency situation, this test can determine if you are having a heart attack. 

When your heart beats, electrical waves move through it. These impulses help to coordinate muscle contraction to cause your heart to pump blood. Electrocardiograms record how long it takes for electrical waves to move through your heart, if the waves are too slow or irregular and if areas of your heart aren’t working properly. Electrocardiograms are usually performed in a clinical setting, although sometimes physicians prescribe a portable cardiac event monitor that patients wear at home. 

What to expect during an electrocardiogram

Preparing for your procedure 

You should wear comfortable clothing to your test, including an easily removable shirt. Be sure to avoid any greasy or oily skin products, such as lotion, as well as hosiery. Electrocardiograms are noninvasive, so no other preparations are required. If you are a male, it is possible your chest will be shaved before the test begins. 

During your procedure

During an electrocardiogram, a technician will apply electrode patches to your chest, arms and legs. You’ll lie flat on a table while a computer creates a picture on graph paper of your heart’s electrical activity. No electricity gets sent through your body during this test, which takes about 15 minutes. Electrocardiograms are not painful. 

After your procedure

Most patients have no instructions to follow after an electrocardiogram, although this depends on your specific medical condition. The results of this type of electrocardiogram are referred to as a ‘resting’ EKG/ECG. Since this test sometimes accompanies an exercise stress test, your results might be compared to the EKG/ECG of your heart during physical activity. 

Depending on the results, your doctor may order additional tests or refer you to a cardiovascular specialist.