Veterinary Teaching Hospital

How To Apply a Holter Monitor a Dog

1. Cut or tear 10 pieces of white tape approximately 2 inches long.

Horse: Step 1

2. Shave 5 spots (2 inches x 1.5 inches) to form a circle around your dog’s chest. Start by shaving a spot directly in between the shoulder blades. Next, on your dog’s right side, shave a second spot halfway between the spine and the sternum, and a third spot on the chest behind the elbow. Do the same of the left side of the chest for spots 4 and 5.

Each spot should be an inch to two inches away from each other with the last spot being directly caudal (towards the tail) to the elbow of the dog. Make sure that each spot is well shaved by shaving against the fur. Try to keep the spots symmetrical on either side of the dog.

Shaved Dog

3. Attach electrode patches to the end of each of the 5 patient lead cables. Apply a small (pea-sized) amount of electrode gel to the center of each patch before attaching to the skin.

4. Remove the backing, add the electrode gel and stick the white electrode patch to the shaved area between the shoulder blades. Take two pieces of the prepared white tape and place over the sides of the electrode. Do not cover the colored part, just the back of the sticky electrode.

Attach Electrode

5. Proceed to the next shaved patch down the left side of the dog. Attach the red colored electrode to this spot and place two pieces of white tape to either side of the electrode.

6. Continue down the left side of the dog. Place the brown electrode in the same manner as the red electrode.

Attach Red Electrode

7. Go to the right side of the dog. Place the green patch on the middle shaved area and the black patch on the lowest area, behind the elbow.

It is very important for the electrode patches to have excellent contact with the dog’s skin to avoid artifact, which interferes with the recording of the holter.

Right Side

8. The lead wires and cable should then lay forward on the dog so they are sticking out towards the neck while the Elastikon is taped on. Place a strip of Elastikon over all the electrodes and the white tape. Start on the right side of the dog and attach it approximately an inch below the black electrode. Hold the end against the dog’s body while unrolling the Elastikon and continue to stick it to the dog while unrolling it over the dog’s back. Wrap the Elastikon all the way around the dog by going under the dog’s chest. Once the Elastikon has been placed, firmly press down on it over the areas with the electrode to help keep the patches and electrodes in place.

Note: Do not pull too tightly! Elastikon stretches and you could make it too tight around the dog. Lay the tape loosely onto the dog, do not pull or tug it.

Wrap Dog
Wrapped Dog

9. Apply the holter vest. The holter vest has a pocket on the top for the monitor and a hole on the underside to feed the patient cable through. Insert the end of the patient cable through the hole and up through the pocket. A note about our vests: They are always machine-washed between patients, but the fur does not always come off the fleece and Velcro.

A note about our vests: They are always machine-washed between patients, but the fur does not always come off the fleece and Velcro.

Vest 1
Vest 2

10. Adjust the Velcro straps under the neck and belly to ensure a snug but comfortable fit.

Holter is on

11. Attach the monitor:

  1. With the monitor face down, the cable connection port towards you and the words Trillium 5000 at the top, the left side of the monitor is where the memory card has been inserted for you. You will not need to access this compartment.
  2. The right side door is for the battery. Open the battery compartment and insert an AA battery, observing the polarity diagram in the compartment. Securely close the battery compartment.
  3. Attach the cable to the monitor. With the monitor facing up and the Forest Medical logo towards the right, attach the head of the patient cable to the cable port. The cable leads should go to the right. Pinch the long sides of the cable head and snap it into place on the monitor.
Monitor 1
Monitor 2

12. Start the monitor and adjust the settings.

  1. Turn on the monitor by pushing any keypad button. The first screen will ask you to input a patient ID number. Ignore this screen and scroll to the right using the button. You should be able to see the ECG tracing on CH1. Push the button repeatedly to scroll through CH2, CH3 and the SETTINGS menu until you get to the DATE/TIME menu.
  2. If the date and time are correct, press the button. Or use the up and down arrow buttons to move to the item that needs to be corrected. Use the left and right arrow key to change the time or date. Press the button again to accept the changes.
  3. Start the holter recording by using the right arrow key to move over to the START menu, then press the key to start the recording.
Adjust Settings
Start Monitor

13. Place the monitor into its protective pouch and then put it into the pocket on the back of the vest. Coil the rest of the patient cable and push it into the pocket as well to protect it from chewing and scratching.

Note: Patient cables are expensive to replace! If your dog damages the cable you will be billed for a replacement!

14. Record the start time on the patient diary. It is important to make a note of your dog’s activity level on the diary, even if significant episodes are not observed.

Monitor into Pouch

The monitor needs to remain running for 24 hours, at which time it will shut itself off and the screen will be blank. While the monitor is recording, we encourage you to let your dog participate in normal daily activity—the only thing to avoid is getting the monitor wet (baths, swimming, snow/rain).

To Remove The Monitor: Leave the monitor in the vest pocket with the patient cable attached to the port. Remove the vest and carefully remove the Elastikon. (This can be somewhat painful — use adhesive remover for sensitive dogs.) It is best to remove the Elastikon from the front to the back, instead of up and around, so that it peels off with the grain of the fur.


Please discard the battery, Elastikon, white tape and electrode patches.

Return any unused supplies —- THANK YOU!!

Washington State University