In 2021, we will be embarking on the next phase of our DCM research: we will be doing a Holter study on 100 Deerhounds to see what role arrhythmias play in Deerhound DCM.
As you may remember, we had hired Dr. Kate Meurs to do an initial study on the genetics of DCM in Deerhounds, and she did not find any obvious disease-causing mutations common to all the affected dogs’ DNA she studied. In our discussions with her about next steps, she said it would be very helpful if we knew more about what DCM looked like—its clinical presentation—in Deerhounds, so that is the direction we decided to take.
Arrhythmias and Deerhound DCM
For many years, we have known that some cases of Deerhound DCM include heart arrhythmias and some don’t. The arrhythmias found were usually ventricular premature contractions (VPCs) or atrial fibrillation (A fib).
VPCs are not just found in Deerhounds—they are found in other dogs as well, and in some other breeds, such as Doberman Pinschers, VPCs are associated with DCM. We know that Deerhounds do not have the mutation that causes this type of DCM in Dobies. But could they still have a DCM that is similar?
A fib is another arrhythmia that is found in Deerhounds. Some dogs seem to have “lone” A fib that doesn’t appear to be related to DCM, but there are documented cases where it does seem to be related, so we will see if we can tease out more information about this arrhythmia.
Partnership with the U.K. Deerhound Club
Meanwhile, the U.K. Deerhound Club has for several years had an extensive cardiac ultrasound program where they have ultrasounded dozens of Deerhounds, both to publish normal parameters and to see what they could learn about what DCM looks like in Deerhounds. And they, too, found that some Deerhounds with DCM had VPCs or A fib.
When a dog—or person, for that matter—is diagnosed with an arrhythmia, the best way to learn more about it is to monitor the heartbeat over time. So a monitor was developed—a Holter monitor—that could be worn safely and comfortably for an extended period of time. In dogs, it’s typically 24 hours. While several breeds, such as Dobies and Boxers, include Holter monitoring as part of routine health screenings, very few Deerhounds have been Holtered (usually after a problem has been found), so we know very little about arrhythmias in Deerhounds.
We have been keeping in close touch with the UK club’s cardiac team, and, while they have done cardiac ultrasounds on many dogs, they have only been able to Holter monitor a few affected dogs. So this begs the question of what comes first: the arrhythmias or the signs of DCM on the cardiac ultrasound? Can Holter monitoring be an effective way to detect some cases of DCM early in the disease process?
The Holter Monitoring Project
We are embarking on this phase of our DCM Project to start to answer these questions. Our plan is to Holter monitor up to 100 Deerhounds in the next year or so to see whether we pick up any dogs with arrhythmias, and then to monitor those dogs to follow the progression, if any, of DCM in those dogs via cardiac ultrasound and follow-up Holter monitoring. We also would like to get tissue samples from these dogs’ hearts when they die, no matter what they die of, as well as any other dogs diagnosed with DCM and some healthy controls, to see if that gives us any clues to the cause(s) of this disease in Deerhounds.
Here is the full proposal, but, in a nutshell, we have purchased two Holter monitors to send to owners to put on their dogs for 24 hours. The data will then be sent to Dr. Jo Harris, one of the cardiologists working on the UK Deerhound DCM project, to prepare the report from the data. The report will be reviewed by Dr. Harris or Dr. Meg Sleeper, a cardiologist at the University of Florida Vet School who helped us design this project.
If any dogs have an arrhythmia as per the Holter monitor, we will pay up to $500 towards the cost of a cardiac ultrasound with a board-certified veterinary cardiologist.
As you can see in the proposal, buying Holter equipment and running Holter sessions are expensive. So we can only commit to monitoring up to 100 dogs for one year’s worth of testing. That will use up all of the more than $15,000 we raised for DCM research last year and will also cause us to dip into the Bunnie Austin general fund for approximately another $9,000 (which it can well afford). Depending on how it goes—the number of dogs we Holter and the number of dogs with arrhythmias—we will decide whether, and, if so, how to move forward with the program.
As you can imagine, it will not be a lot of dogs that will be diagnosed with arrhythmias—we are estimating if we do the full 100 dogs for which we have budgeted, there will be approximately five. Therefore, it is crucial we monitor as close to 100 dogs as possible. We would like to do more but do not have money in the budget to do them. However, if the response is great and we get sign-ups for more than 100 dogs, we will do additional fundraising and/or start charging after the 100th session in order to cover the approximately (because exchange rates are involved) $163/dog it costs to do one Holter session. We’ll just have to see how it goes, but we encourage you to sign up early to ensure that you will not be charged for the Holter session beyond paying postage to send the data card in and forward the equipment to the next person on the list. As soon as we have a start date, we will start the sign-up process. To keep up to date about this project, we recommend that you subscribe to our blog (found on the lower right of any page of this web site.
Genetic Study Next Phase
Additionally, the UK Deerhound Club is moving forward with a genetic study (building on Dr. Meurs’s work), and we want to support them in any way we can. So we still want blood samples from dogs affected with any type of DCM. If you have a dog diagnosed with DCM, please consider providing blood and your dog’s test results for this study. Samples go to our CHIC DNA Bank (if your dog’s DNA is already in CHIC, then just send test results and a health update to CHIC). If you are providing a sample, then we are asking that you provide 7-10ccs, a bit more than usual, so we can send the British project as much as they need and also keep some here for future projects.
We are putting together the instructions for the necropsy study right now and will post them shortly.
Finally, we are all set for funding for now, but if we get more than 100 dogs signed up for Holter sessions or decide it is worthwhile to continue this project for more than one year, we will need more money to do either of these things. If you want to support this project, donations are always welcome.
This project has been a long time coming, but we hope it will give us significant insight in DCM in our breed that will not only help us get closer to a genetic test but could also help us with treatments that improve both the quantity and quality of life for our DCM-affected dogs.