Holter Monitor in Cats

By Ryan Llera, BSc, DVM; Ernest Ward, DVM

What is a Holter monitor?

A Holter monitor is a portable device used to monitor the electrical activity of the heart continuously. Its extended recording period is useful for observing occasional or intermittent cardiac arrhythmias that may be difficult to identify during a routine clinical examination.

What does a Holter monitor do?

The monitor is usually worn for twenty-four hours during normal activity. You should keep a diary of what activities your cat does while wearing the monitor such as playing, eating, or sleeping. There is a button on the monitor for you to press allowing you to mark an observed event such as a fainting episode. After twenty-four hours, you will return the monitor and diary to your veterinarian's office. Your veterinarian will analyze the recorded ECG looking for abnormalities.


Why does my cat need to wear a Holter monitor?

A Holter monitor is typically used for patients with a history of syncope (fainting) or if your veterinarian detected abnormal or irregular heartbeats during a clinical examination of your cat. Some of the uses include:

  • determine heart rate variability during normal activity, exercise, and rest or sleep
  • diagnose the type of arrhythmia (abnormal or irregular heartbeats or rhythm) in order to determine the correct treatment
  • analyze the effectiveness of prescribed cardiac drugs
  • evaluate pacemaker function

How does my cat wear a Holter monitor?

The Holter monitor used for cats consists of a special vest containing the monitor attached to several ECG lead wires. It is very unobtrusive, and most cats ignore its presence very quickly. Your cat will most likely have several areas of fur shaved to attach the ECG leads to the skin.

If your cat requires the use of a Holter monitor, your veterinarian will give you specific instructions on its use. This relatively simple but highly effective device has saved countless human and animal lives since first introduced almost seventy years ago.

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