Skip to content

What is a Holter monitor and why does my pet need one?

By:  Risa Roland, DVM, DACVIM (Cardiology)

A Holter monitor is a 24-hour electrocardiogram (ECG or EKG).  An ECG is a tracing of the electrical activity of the heart that appears as lines on paper.

If you place a Holter monitor on a patient, you are able to see the ECG trace for a whole day.  This is helpful to see if there are any abnormalities in the electrical activity of the heart (abnormal heart beats) over the course of a day.

In addition, a Holter monitor is helpful to determine if an abnormal heart beat occurs with a certain activity (like sleep or exercise or excitement).  The owner of the patient with the Holter monitor keeps a Holter diary and records the activity of the patient.  Then, the ECG can be evaluated at the time of the activity to determine if there is an abnormal heart beat.