A Holter monitor is a portable device that records the electrical activity of the heart (ECG) over a period of time typically up to 24 hours. The electrodes are attached via pads to the chest of the dog and the leads run to the recording device which is no bigger than a pack of cards.
If an ECG is done in the clinic, although an excellent screening test, it is typically only done over 2 minutes recording approximately 200 beats. An average dog’s heart will beat 150,000 times per day. Therefore, the in clinic recording will only be detecting 1/10 of 1 percent of the daily electrical activity and the chance of detecting an intermittent problem is less than 5%.
Holter monitors are used to record episodes of fainting, weakness and occasionally seizures that may occur away from the clinic at random times during the day or night.
They are also used to assess the severity of a cardiac rhythm disturbance, again at the comfort of home when they are acting normally and relaxed. In addition, if treatment is then started, the reduction in frequency of arrythmias can then be assessed to see if it has been successful or if a dose adjustment required.
Boxers and Doberman Pinchers will sometimes have heart disease that can only be detected by one of these Holter monitors. This may be an important screening test especially if a dog is being considered for breeding.
If you feel that your dog has signs of weakness or if you feel that a cardiac assessment may be appropriate for your pet, please contact the clinic for more information.