– Broken Hearts, Broken Dreams –

July 1, 2002 – Last week we met Phlash, a 5-year-old fawn Great Dane who lost his battle with dilated cardiomyopathy (DCM). This week you'll be meeting Karen Quatman's Harley, who succumbed to DCM two years ago. He was 7 years old. Before we get to Harley's cardio story, which appears below, I'd like to discuss certain aspects of the disease. Later I will tell you about some efforts underway to better understand DCM. Please keep in mind that what you read here is just a layman's interpretation (my own). If you have questions and concerns about your own dog, you should contact your veterinarian or a canine cardiologist for more information.

What is dilated cardiomyopathy (DCM)?

Dilated cardiomyopathy (DCM) is a primary heart muscle disease. It is progressive in nature and there is no cure. Dogs with undiagnosed dilated cardiomyopathy can suddenly drop dead for no apparent reason. Other DCM dogs may suffer from congestive heart failure and die within months of their initial diagnosis. Many breeds of dogs are stricken with DCM and the disease is somewhat different for each breed. (Breed specific variations include age of onset, rate of progression, type of arrhythmia, sudden death versus congestive heart failure, etc.) Unfortunately, the Great Dane is reported to be the second most common breed of dog afflicted with DCM, second only to the Doberman.

Last year at the GDCA National Specialty I attended a lecture titled, "Dilated Cardiomyopathy in the Great Dane." The lecture was presented by Dr. Kathryn M. Meurs, a professor of cardiovascular medicine at Ohio State's College of Veterinary Medicine. Dr. Meurs is researching the inheritance of cardiomyopathy and the use of molecular genetic techniques to study both inherited and acquired cardiovascular disease.

Observable Symptoms: - Coughing - Shortness of breath - Exercise intolerance - Abnormal breathing rate - Weight loss Clinical Symptoms: - Heart murmur - Abnormal heart beats - Gallop rhythm - Electrical abnormalities - Dilation of the left ventricle

According to Meurs, dilated cardiomyopathy in the Great Dane is usually characterized by enlargement of the left ventricle, decreased pumping ability and electrical abnormalities. Clinical presentation in the early stages of DCM often goes undiagnosed. A heart murmur may be heard on the left side and abnormal heart beats may be observed during a routine electrocardiogram. An echocardiogram may reveal mild leaking of the mitral valve and/or mild dilation of the ventricle. As the condition advances, the dog may exhibit coughing and shortness of breath, exercise intolerance, increased or decreased rate of breathing and weight loss. An examining veterinarian will often detect a heart murmur (very common), "gallop" heart rhythm, and/or a rapid, irregular heart rate.

Advanced dilated cardiomyopathy is considered a fatal disease. Certain medications can be used to help the dog remain comfortable. Digoxin may be given to help the heart pump. Lasix may be given to reduce fluid in the lungs. Enalapril, Lisinopril and/or Vasitec help with heart failure and dilate blood vessels. But medicating and maintaining a DCM patient the size of a Great Dane can be an expensive (and emotionally draining) proposition; many pet owners can't afford to do so for very long.

Living (and dying) with DCM
Obviously, the "DCM experience" is not the same for every dog and every family. Harley (pictured throughout this article) was not the first Great Dane that Karen Quatman lost to DCM. He was her third. I asked Karen to tell us about Harley's case:

Harley's Story By Karen Quatman Harley was born on October 18, 1992. He came into our lives as a 17-week-old puppy when Harley’s breeder – my good friend – asked us to babysit Harley while she was caring for her sick child. We agreed. Shortly thereafter I called my friend and told her we were in love with Harley and he was staying forever. She readily agreed and we believe that was her plan all along! One day when Harley was approximately 2 years old his breeder called me, clearly upset. Harley’s father (age 5 1/2) was extremely sick and the vet wanted her to get him to a cardiologist as soon as possible. Could I recommend someone? We made an appointment with a cardiologist who, from past experience, I knew to be very good.The appointment was the next day. I offered to tag along for moral support. I arrived at the clinic to find Harley’s father lying on the floor on his right side. His breathing was very labored. He was weak and made no attempt to rise when I arrived. With every breath he took, you could hear fluid moving around his lungs. Pneumonia. I knew it was bad. He was shocky. An echocardiogram was given. Dilated cardiomyopathy was confirmed. He was in congestive heart failure and the prognosis was poor. He died months later. Screening for DCM Because Harley's father had DCM, I decided to take Harley in for a screening. I had already lost my first two Danes to dilated cardiomyopathy (fawn half-brothers, obviously not related to Harley), so I was all too familiar with the disease. Harley was examined. An innocent murmur was heard. DCM was ruled out by an echocardiogram. We ran another echo three years later when Harley was 5. The same results were found. Innocent murmur, DCM ruled out by echocardiogram. In December of 1998, when Harley was 6 years old, I started to notice some changes in his breathing pattern. Sometimes while he slept, I would hear a loud "snore" which would be followed by a pause. I described it to my vet as something similar to a sleep apnea. My vet performed a thorough exam and found nothing. She told me I could take Harley back to the cardiologist for a another screening if it was concerning me. Since everything else appeared normal, I decided to wait and see. A month later, in January of 1999, I received a call from a woman who owned Harley’s 3-year-old nephew. He was out of Harley’s full sister. Harley's nephew had just been diagnosed with dilated cardiomypathy, atrial fibrillation and secondary valvular regurgitations. He was in bad shape. After hearing this, I became hypersensitive to any change in Harley’s health. The warning signs By March I knew Harley had it. For the life of me, I cannot remember how I knew, or why I knew, but I knew. It may have been the subtle changes. Those loud snore sounds became more frequent. The pauses in his breathing more frequent. Harley's heart rate remained normal but he was slowing down. The black circles around his eyes grayed almost overnight. His energy level dropped. He started missing meals, although he was still a good weight. I already had an appointment to take Harley in for a re-screeening in April. Unfortunately, that same month, I lost my 3-year-old male suddenly and tragically to complications from a neuter. I was devastated by the loss and I just couldn’t bring myself to hear what I already knew, so I postponed Harley's appointment for a month. Diagnosis and treatment I took Harley back to the cardiologist in June. I wasn't surprised when he was diagnosed with dilated cardiomyopathy. (Moderate DCM, 14% fractional shortening.) I made the decision to wait three weeks before starting Harley's medication. Why? We were going on vacation. A previous cardio dog of mine had a toxic reaction to Digoxin and I didn’t want to take the chance that Harley might have one, too. So we waited until we came home to start the Digoxin and Zestril. In the interim, Harley was on 2 grams of carnitine twice a day. He was also getting 1000 IU of vitamin E, 220 mg of CoQ-10, probiotics, digestive enzymes and milk thistle. Harley started a downhill spiral shortly after we returned from vacation. In that short amount of time he developed hind-leg edema. His thighs were double their normal size. He was completely exercise intolerant. His tongue was blue. His groin was puffy with fluid. He was over-consuming water due to the Lasix and would often cough and gag. For the next 11 months Harley had his ups and downs. There were times when we didn’t think he would make it through the night. Then he would rally. Then he would crash. Then he would rally. It was a constant roller coaster ride for all of us. Saying goodbye Our decision to say goodbye was not an easy one. I kept thinking that he had a history of rallying before and maybe he could rally again. Deep down in my heart, I knew he couldn’t – and frankly, I don’t think Harley wanted to rally anymore. It was painful to watch him breath while he slept. His breathing was so labored. He was tired. He had fought a good fight. As much as I didn’t want to accept it, Harley let me know it was time to let go. He didn’t deserve to suffer needlessly. He deserved a dignified end. Harley was euthanised in his own home, on his bed, surrounded by the people who loved him. We miss him so. – Karen Quatman

What causes DCM in the Great Dane?

As we've seen, DCM hurts everyone it touches. So which dogs get it, and why? There are no definitive answers to that question. A number of causes have been suggested ranging from parvovirus to specific nutritional deficiencies. According to Dr. Meurs, there is no evidence that parvo is implicated in the development of the disease in Great Danes; molecular analysis has been performed to look for it and no relationship has been found. She also states that "there is no evidence that Taurine deficiency or L-Carnitine deficiency is implicated in the development of dilated cardiomyopathy" in the Great Dane. Dr. Meurs has found, however, persuasive evidence that suggests DCM in Great Danes might be an inherited trait, more specifically an X-linked recessive trait. If her preliminary research proves true, the implications for both breeders and puppy buyers could be enormous.

More to come...
Next week we'll look a little more closely at Dr. Meurs's research. In the meantime, if you would like more information on the clinical and practical aspects of DCM, the following links might be helpful:
VetCentric Pharmacy - article on DCM

Canine Inherited Disorders Database - article on DCM

Petplace - article on DCM

For the record, some might disagree with Dr. Meurs's comments on Taurine and L-Carnitine:

University of Parma (Italy): Dilated Cardiomyopathy
in a Family of Great Danes, Efficacy of Oral L-Carnitine

UC Davis: Dietary Taurine Deficiency and Dilated
Cardiomyopathy in Dogs

However, it pays to dig a little deeper – as most dogs will tell you! Dr. Mark Kittleson (UC Davis) ran a well-known study, the Multicenter Spaniel Trial (Taurine- and carnitine-responsive dilated cardiomyopathy in American cocker spaniels with decreased plasma taurine concentration). He was later quoted as saying, "Taurine deficiency and taurine and carnitine responsiveness are not totally limited to American cockers since we do see it on occasion in other dogs, but we never see it in the 'common' breeds that get DCM like Great Danes." (For more information about the MUST (Multi Spaniel Trial) study and the origin of Dr. Kittleson's comment about Great Danes, click here.)

— ©2002 by Ginnie Saunders

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