This page covers the process of using a holter monitor. The links at left give you other information.
WHEN & HOW OFTEN TO HOLTER?: This depends on the breed of dog and the reason for holtering. In boxers, for general screening, annual holters after the dog has reached maturity (2 years) are recommended. A one-off holter test on a boxer is close to meaningless – it has to be a regular check.
Here's my summary of the process in 10 easy steps!
CHOOSE DAY/TIME: Plan for a day when your dog can be active but supervised. Your dog should be able to do all normal activities, but you may want to separate them from other dogs when unsupervised. It's best to attach early in day so you have time to see how the dog reacts before you go to bed.
SHAVE AREAS OF DOG: For best results clip or shave hair where electrodes go– see below. I often visit a vet clinic and get them to shave my dog - have never been charged for this.
PREPARE YOUR DOG: Attaching the monitor can take about 30 minutes especially if you're new to the process. For a ‘hyper dog’ let them run off excess energy ahead of time. You will also need to clean the areas where electrodes go. Use medicinal alcohol/meths to thoroughly remove natural oils (don't use soaps). The skin must be 100% dry.
ATTACH ELECTRODES: Sticky disposable electrodes (from your holter company) will be attached to the shaved patches – see below. You usually have 5 or 7 in total. Some come with ultrasound gel, for others you should add gel to optimise the quality of your recording.
PREPARE RECORDER: Get the recorder ready. What you do varies depending on type. You are likely to need to insert a fresh battery, a tape / SD card, and make a note of start time.
CONNECT LEADS: Leads that are connected to the recorder will now be clicked onto the electrodes in order based the colour of the lead – each recorder comes with instructions.
SECURE LEADS/RECORDER: You need to secure the leads & recorder. Medical or sports tape is put over the electrodes, and a harness, vest or bandages are used for the recorder – see below.
DURING THE READING: Keep a diary of your dog’s day so that if something unusual shows up you can refer back. To make the investment in the test worthwhile it’s best to exercise your dog – if there is anything wrong you want to catch it, not get a false clear test. Keep your dog under adequate supervision - think of your dog having stitches on their back and bandages over the top - that gives you an idea of the kind of supervision while they're wearing the holter. The monitor and electrodes must not get wet. Also avoid them being places where the bandages could get snagged, and avoid other dogs jumping on them or chewing at the bandages.
AFTER 24 HOURS: Work backwards through instructions 7-4 above to remove the device. The electrodes can be hard to remove – you can buy medical products like 'Uni-solve' or orange oil based cleaning products for removing them and the sticky residue.
ARRANGE ANALYSIS: Depending on who you use for analysis (see below) and the type of recorder, you will either be posting off a tape or SD card, or arranging to send data over the internet. You will probably need to complete a form with your dog’s details & payment. You then wait for the PDF report to arrive in your email. (Sample report on separate page).
HOW TO SECURE THE HOLTER
How you should attach a holter monitor depends on the particular monitor you have (the number of leads varies) and your own preferences.
The electrodes and leads are usually secured using adhesive medical or sports tape (available from supermarkets/pharmacies cheaper than from your vet). I recommend using a stretchy tape and one that allows the skin to breath. If your dog has very sensitive skin, you can buy special hypoallergenic tapes in pharmacies. Sometimes bandages are put over the top of the electrodes and leads also. I recommend the self-adhering bandages used by horse people - far cheaper than buying from a vet or pharmacy (check EBay for cheap supplies).
For the recorder itself, I'm aware of three main approaches to securing it:
Special vest, with or without bandages to secure the leads
Harness, with or without bandages on top.
My first holters were done with just bandages but once they came free so I started using a harness which worked well. Now I use a vest, which is simpler and more comfortable for the dog as less bandages/tape. The photos of vests on this page (including the snazzy polka-dot one) are made by my friend Claire Perry (she makes these to sell - contact me for details).
You have the choice of putting the electrodes on the sides of the dog, or under the chest. Details below. With either position, you can also choose whether or not to shave the dog.
HOW DO YOU DECIDE WHICH POSITION? Under the chest means shaving and/or any sticky residue on the skin is less obvious - ideal for show dogs. Putting electrodes under the chest can be awkward & the skin on the chest can be a bit more sensitive when the bandages/electrodes are being removed. Under the chest also means it's much more important to avoid the dog getting wet as wet grass or splashes from wet ground can reach the chest more easily than the sides.
Regardless of where you attach the electrodes, on this page from Alba Medical you’ll find great information on what the different colours do and whether you can still get a useful recording if one detaches.
TO SHAVE OR NOT TO SHAVE?: Shaving seems to increase the chance of getting a good reading. However, of course, shaving is more visible.
Whether you shave your dog for the holter will depend on your needs and also on your dog and how thick and long their hair is, but for many dogs I would recommend at least clippering the hair back a bit to ensure the electrode has a close contact with the skin. After all, the investment of time and money in the test means it's better to do all you can to enhance the chance of a useful reading.
THE SIDE APPROACH: This is the traditional approach to holtering. If you choose to use this position and to clipper/shave your dog, the notes below show the areas where the electrodes will go for a 7 lead monitor - make sure you follow the directions given by your own monitor supplier.
Left side:The first photo shows roughly where the 4 electrodes on the dog's left side will be positioned for 7 leads.
The bottom electrode will be positioned just far enough behind the elbow that the movement of the front leg doesn't affect it - this is more or less in a line down from the withers.
When shaving this side allow for about 18-20cm from the bottom upwards,and about 6cm wide.
Right side: The second photo shows roughly where the 3 electrodes on the dog's right side will be positioned.
When clipping/shaving this side allow for about 15cm from the bottom upwards,and about 6cm wide.
THE UNDER THE CHEST APPROACH: This is the 'new' approach to holtering. The picture on the right shows a bitch sitting after the holter has been taken off. She was not shaved but has a short thin coat.
If you want to use this approach and clipper/shave your dog, use the photo and the notes below as a guide to what areas of the chest to remove hair from. There is also a hook-up diagram for humans which gives an idea of the ideal position for the chest approach using the 7 lead monitor. If hair is removed, a 6cm area should be done for each electrode.
The top pair of (brown and blue) electrodes are right at the top/front of the rib cage (in a human these would be in line with the collar bone). Avoid them being under the elbow as that would be difficult for the dog when they move.
The middle (white) electrode sits right in the centre of the ribcage on the breastbone (sternum) just below the top pair.
The Orange and Red electrodes (second pair up from bottom) go one on either side on the line of the rib cage a little below the bottom of the sternum. In the photo the rib cage wasn't long enough to allow as much of a gap between this pair and the bottom pair as would have been ideal.
The bottom pair of electrodes (green and black) are right at the bottom of the rib cage (or as close as you can get while avoiding nipples!). These two should be further apart than in the photo ideally.
No matter where you live in the world you can easily have holter recordings analysed. I am based in Australasia yet get all my recordings analysed in the USA.Your nearest canine cardiologist or vet school may offer holter tape reading services but they are sometimes expensive. You also need to be careful that the person is knowledgeable about your breed.
NOTE: Different brands of digital monitors use different software so you are limited to where you can get analysis done. This is one of the disadvantages of the digital versus analog monitors but the old analog technology may not be available in the future.
The ideal way to have tapes analysed is when the recording is reviewed by a cardiologist who specialises in the disease you are screening for. For Boxers, Dr Meurs is the expert on Boxer cardiomyopathy and she offers an analysis service where your recording is reviewed by a cardiologist for about US$80 (NCSU Holter service).
If you want a more basic analysis option, Alba Medical (Alba Medical Canine Health Services) offers a basic service without cardiologist and charge about US$30 per report (created with a technician overseeing the process). (See the sample report on separate page.) I have found Alba fantastic to deal with over many years now - in my experience, much more professional than competitors (eg I certainly don't recommend Petcardiology). Whichever organisation you use for analysis, the tape and report remain 100% confidential between you and the company – no one else has access to either unless you give it to them. (For other breeds, contact a breed club for advice – often the USA club website will have useful information on health testing).
If you get a cardiologist assisted service, your report should include their expert opinion on the meaning of the recording. If you use a basic technician service, all you get are numbers which you then need to interpret. I have taken my (home recorded) holter reports to my local cardiologist for advice. They don’t mind, and it is cheaper and easier for me.
WEARING THE HOLTER
The photos on this page are of various of my boxers with the holter. The red bitch with blue bandages is Rosie wearing the holter. She's not a large bitch (21.5") so the holter looks particularly large against her. As you can see she is relaxed and happy with the holter. Some dogs get a bit miserable wearing it - I think it's a personality thing. Those dogs still play quite happily wearing the holter when given a chance, but may sulk a little.
Videos and slideshows showing process of attaching holter with vest