Electrocardiogram (ECG) and Holter Monitoring

Electrocardiograms, also called ECGs or EKGs, detect the electrical activity of the heart and are used to:

• Diagnose heart rhythm problems
• Monitor your heart's health after a heart attack
• Gauge your heart's reaction to new medication

An ECG, which can be performed in your doctor’s office, provides information about your heart’s current rhythm. Or, when your doctor wants to record your heart’s rhythm over time, you can wear a portable device called a Holter monitor for 24 to 48 hours to capture a continuous ECG. Your doctor will prescribe the Holter monitor when he or she wants to learn more about how your heart responds to normal activity during a typical day.

How an ECG Is Performed

A technician will attach about 10 to 12 sensors to your chest, and sometimes your limbs. These sensors measure the activity of your heart for a few minutes.

The information collected from the ECG helps your doctor understand if your current heart rhythm is regular or irregular.

How a Holter Monitor Works

A technician will attach small sticky patches (electrodes) to your chest and connect them to wires from a small monitor. This monitor is placed in a pocket or a small pouch during the entire recording period.

Your doctor will ask you to keep a diary of your activity during the monitoring period so your heartbeat patterns can be matched with different activities. After 24 to 48 hours, you will return the monitor to your doctor's office, where the recordings will be analyzed for any irregularities.

What Your Holter Monitoring Results Mean

Your doctor will consider your results normal if your heart rate falls within the normal range for each of the recorded activities. Abnormal results could indicate an arrhythmia (irregular heartbeat), an epileptic event or that your heart is not getting enough oxygen. The monitor may also detect a conduction block, a condition in which the electrical impulses from the atria are either delayed or do not continue into the ventricles.