What is a Holter monitor?

A Holter monitor is a painless test that records your heart’s electrical activity continuously for one to two days. A Holter monitor is a longer version of an EKG (electrocardiogram). It helps your doctor diagnose and monitor abnormal heartbeats (cardiac arrhythmias) and decreased blood supply to the heart muscle (myocardial ischemia). 

A Holter monitor can detect abnormal heartbeats and other abnormal EKG changes that a standard EKG can miss. Standard EKGs only record the heart’s electrical activity for a short period of time. A continuous Holter monitor is more likely to detect abnormalities that occur periodically. 

A Holter monitor is only one method used to monitor and diagnose heart conditions. Discuss all of the options for evaluating heart health with your doctor to understand which options are right for you. 

Why is a Holter monitor performed? 

Your doctor may recommend a Holter monitor to evaluate your heart health. It provides important information about your heart health in relation to your age, physical exam, medical history, and other tests. A Holter monitor by itself cannot diagnose all types of heart conditions or predict future heart problems.

Your doctor may recommend a Holter monitor to diagnose, determine the severity of, and guide treatment of these conditions:

  • Cardiac arrhythmias including heartbeats that are too fast, too slow, or irregular, especially arrhythmias that do not occur all the time 
  • Coronary artery disease (CAD), a buildup of plaque on the walls of the coronary arteries that supply blood to the heart. CAD can cause poor blood flow to the heart muscle, called ischemia, and chest pain, called angina. A Holter monitor is useful in detecting ischemia when there is no chest pain or other symptoms.

A Holter monitor can also help determine if certain 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 a Holter monitor?

A nurse or technician will set up your Holter monitor. The following doctors order and interpret Holter monitor testing: 

  • Cardiologists specialize in diagnosing and treating diseases and conditions of the heart and its blood vessels. 
  • 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.
  • Electrophysiologists are cardiologists who specialize in treating heart rhythm disturbances (arrhythmias).
  • Interventional cardiologists are cardiologists who specialize in diagnosing and treating heart disease using catheter procedures and radiological imaging
  • Pediatric cardiologists specialize in diagnosing and treating diseases and conditions of the heart and its blood vessels in children.

How is a Holter monitor performed?

Your Holter monitor will be applied in a medical setting. Testing generally includes these steps:

  1. Your provider will attach three or four sticky, painless patches, or electrodes, to your chest. Your provider will shave small areas of your chest if needed. The electrodes are attached to a Holter monitor device by wires. The monitor is about the size of a Smartphone. You wear it clipped to a belt or carry it in a pouch slung over the neck or shoulder.
  2. You will likely go about your normal activities during your Holter monitor test. Doctors sometimes limit activities or provide specific instructions for activity level.
  3. You may need to press a button on the Holter monitor if you have symptoms, such as chest pain, dizziness, or a racing or pounding heart. This will help your doctor evaluate your results by marking the exact time of symptoms.
  4. You may keep a log of all your activities and any symptoms.
  5. At the end of your Holter monitor test period, you will remove the electrodes and return the device and your activity log to your doctor. The test period is usually 24 to 48 hours long. 
  6. Your doctor will evaluate the Holter monitor results and discuss them with you.