Dilated cardiomyopathy (DCM) is a disease of the heart muscle that affects some adult Great Danes, and knowing the early signs helps.
The heart muscle weakens and stretches, so the heart pumps less well. Over time that can lead to heart failure or dangerous rhythm problems.
In adulthood. In one screening study (Tarducci et al.), the affected dogs were 13 months to 6.5 years old.
A dog can have it for months or years with no outward sign. Knowing the early signs helps you catch it sooner.
If you are bringing home a puppy, there is nothing for you to do about DCM yet. This page is here so you know what to watch for later.
Written from the cardiology presentation at the 2026 Great Dane Club of America National Specialty and checked against published sources. Where we could not find one, we say so. It is not veterinary advice; your dog’s veterinarian or cardiologist makes the clinical decisions.
Breeding dogs: the presenters recommended a yearly echocardiogram plus a 24-hour Holter monitor from a veterinary cardiologist, starting around age 2 to 3.
Pet owners: this is the standard for breeding dogs. If you want screening for a pet, ask your vet for a referral to a veterinary cardiologist. A physical exam alone does not catch hidden-stage disease.
Count at home. Breaths per minute while your dog sleeps, staying above about 30 to 35, is an early sign of fluid in the lungs. Call your vet.
How Is DCM Screened in Great Danes?
A cardiologist screens with an echocardiogram and a 24-hour Holter monitor. Blood tests help but do not replace them. Chest X-rays confirm heart failure, and they do not screen for DCM, because an early-stage heart can look normal.
What Are the Stages of DCM?
The heart is structurally and electrically normal. Every Dane starts here, and no medication is indicated.
Echo changes, arrhythmias, or both, with no outward signs. This stage can last months to years.
Fluid in the lungs or belly, weakness, or fainting.
What Can I Watch for at Home?
A smartphone ECG such as KardiaMobile records a 30-second rhythm strip. In a 2019 study (Vezzosi et al.), 89% of owner-made tracings were readable, though most of the dogs already had heart disease. It does not replace a Holter.
What We Do at 7 Sisters
At 7Sisters Farm in the Champaign-Urbana area of Illinois, we have a veterinary cardiologist examine our breeding dogs for the OFA advanced cardiac database, which requires an echocardiogram, and we post the results. Each dog’s OFA record lets you look up its relatives, so you can see the whole family and not only one dog. Our litter pages link to the parents’ OFA results, for example Ezra × Mia.
How to Help
Report any later heart diagnosis back to your dog’s breeder, so the breeder can see what happens in a litter over time. You can also contribute to the Great Dane DCM genetics study at NC State (Dr. Kate Meurs, Veterinary Cardiac Genetics Laboratory).
How to contribute
- Which dogs: The lab wants samples from adult Danes both with and without DCM. Healthy dogs serve as controls.
- The sample: Your vet draws 1 to 2 ml of blood into an EDTA tube. It needs no ice or overnight shipping. Mail it within a few days, and refrigerate it until then.
- What to include: The lab’s submission form, your dog’s cardiologist report (required), and a copy of the pedigree (strongly preferred, though Danes without pedigrees, such as rescues, are accepted).
- The form and address: Both are on the study page.
For Breeders and the Curious
The sections below go deeper into the numbers and the genetics. You do not need them to care for your dog.
How Common Is DCM in Danes?
Published prevalence numbers range from about 1.5% to 47%. The spread mostly reflects how each number was measured, not real differences in how common the disease is.
The 1.53% figure comes from one-time exams, mostly of young show dogs, so it sits at the bottom of the range. DCM shows up with age, so a clear exam at 2 says little about the dog at 7.
If lifetime risk is anywhere near the upper range, we think removing every carrier from breeding is not realistic. Selecting for later onset and for longer-lived families looks like the better goal.
Sources and details for each bar
| Source | Prevalence | Why it differs |
|---|---|---|
| GDCA National Specialty OFA cardiac exams, 2008–2025 (2026 seminar) | 1.53% (19 of 1,238) | Mostly young show dogs, one exam on the day, mostly without a Holter. A snapshot, not lifetime risk. |
| Hospital population (2026 seminar; Sisson & Thomas, 1995) | 3.9% | Only dogs sick enough to be seen, so it misses hidden-stage cases. |
| Tarducci et al., 2003 | About 11.9% (7 of 59) | Dogs that owners reported as healthy, checked with an exam, ECG, and echo, so it catches hidden-stage disease. A small sample. |
| Stephenson et al., 2012 (UK) | 35.6% | Echo and ECG screening of 107 client-owned dogs, with a Holter in only 20 of them. Closer to cumulative risk. |
| Same UK dogs (Stephenson et al.), amended echo reference intervals | 47% | Same dogs, different definition of “affected.” |
The jump from 35.6% to 47% in the same dogs shows how much depends on where the echo cutoffs are set.
The seminar also showed the Nationals results year by year. Rates mostly sit between about 0 and 2%, with one spike near 6% in 2017. The 1,238 dogs over 18 years average about 70 a year, so that spike is about 4 or 5 dogs and is likely noise. There is no meaningful trend. The chart leaves out equivocal findings, which are the borderline dogs breeders most need to know about.
Screening details
The presenters wanted heart volumes measured by Simpson’s method of discs.
- Echo method matters. M-mode (Teichholz) volumes are unreliable in a dilated heart, so numbers from different methods cannot be compared directly.
- Holter counts. The presenters described fewer than 50 ventricular premature complexes (VPCs) in 24 hours as normal and more than 300 as diagnostic, with 50 to 300 on two recordings within a year also diagnostic. Davis et al. give these as the accepted criteria for Dobermans, so treat them as borrowed from that breed. Published studies often use a 100 VPC cutoff instead (for example, Stephenson et al.), so check which cutoff your cardiologist uses.
- Blood tests. NT-proBNP and troponin I are supporting tests. They can miss different forms of the disease.
Treatment and outlook
In PROTECT, pimobendan in the occult stage delayed heart failure or sudden death by a median of 277 days (441 days on placebo, 718 on pimobendan). The proportion of dogs reaching the primary endpoint did not differ significantly between the groups, so the benefit is best described as more time, not a proven prevention. The trial was in Dobermans.
The presenters estimated survival at about 6 to 12 months after heart failure develops. We have not found a published source for that range. Atrial fibrillation (an irregular, often fast rhythm in the upper chambers), fluid in the belly, and a very weak heart contraction all worsen the outlook, and a typical Dane presentation can have more than one.
What Is Different in Danes
- The presenters said that up to 70% of Danes are in atrial fibrillation when heart failure is diagnosed, and up to 50% have ventricular arrhythmias. We have not found a published source for those percentages.
- A Dane’s Holter should be read for atrial rhythm as well as VPC counts. Davis et al. show an ECG and a Holter recording from Great Danes with no symptoms and atrial fibrillation (Figures 1 and 2).
- Many screening and treatment numbers came from Dobermans. The main pimobendan trial (PROTECT, Summerfield et al., Journal of Veterinary Internal Medicine, 2012) enrolled 76 Dobermans, and its body-size table stops at about 50 kg. Many adult Danes weigh more.
- An in-office ECG tends to overestimate heart rate, so the target for rate control is usually judged on a monitored average.
Not Every Case Is Genetic
These can look like genetic DCM on an echocardiogram:
- Infections, including Chagas disease, tick-borne diseases, and viral illness.
- Low thyroid, which can reduce heart contraction but is rarely the sole cause of heart failure.
- A sustained fast heart rate. Atrial fibrillation can itself drive the heart to dilate.
- Doxorubicin, a chemotherapy drug that can damage the heart. A 2026 review lists higher cumulative dose, breeds prone to DCM, and higher body weight as risk factors in dogs, so it matters for giant breeds treated for lymphoma or sarcoma.
- Diet. In its 2019 update the FDA reported that 93% of the reported products contained peas and/or lentils, and it said no causal link had been identified. See our feeding guide for how we apply this.
An affected dog should be screened for these before anyone counts the case as genetic. An infection-damaged heart can look identical to genetic DCM on an echo, and counting those dogs as affected dilutes the signal in pedigree studies and genome scans.
Ask your veterinarian about tick-borne disease (Ehrlichia, Bartonella, Lyme, Rocky Mountain spotted fever), especially for rural Midwest dogs, with a tick panel such as 4Dx plus Bartonella testing. Ask about Chagas disease (spread by kissing bugs, mainly a southern U.S. concern) if the dog has lived or traveled there. Parvovirus in puppyhood can also leave lasting heart damage.
Genetics: What Has Been Tried
| Year | Study | Finding |
|---|---|---|
| 2001 | Meurs et al., JAVMA 218(5):729–732, 17 Danes | Pedigree analysis suggested X-linked recessive inheritance. Not definitive. |
| 2010–11 | Meurs, candidate X-linked genes (AKC Canine Health Foundation grant record) | No causal mutations found in two X-chromosome genes linked to human DCM. |
| 2012 | Kolicheski, master’s thesis, Swedish University of Agricultural Sciences (Uppsala), genome-wide association study of 62 cases and 65 controls | Two regions on chromosome 19. The study was small, and it is a thesis, not a published paper. |
| 2014–15 | Meurs, whole-genome sequencing (AKC Canine Health Foundation grant record) | A long list of candidate variants was filtered down. No Dane variant has been published. |
Testing the X-linked idea against pedigrees
X-linked recessive inheritance predicts that an affected sire cannot pass it to his sons, that affected males get it from a dam (usually an unaffected carrier), that every daughter of an affected male is a carrier, and that affected females are rare.
One documented affected sire with affected sons would argue against pure X-linkage. The UK study found that. In its pedigree analysis of 22 dogs from two extended families, both pedigrees showed male-to-male transmission, which excludes X-linked inheritance. The authors judged an autosomal dominant trait most likely, though they did not completely exclude polygenic inheritance. The chromosome 19 signal from the Swedish study is autosomal, which points the same way.
A caution from other breeds
The juvenile DCM test for Portuguese Water Dogs detects a linked marker, not the causal mutation, and the lab notes that a small share of results can be wrong in either direction. In a 2013 study, 3 of 33 Boxers with DCM did not carry the striatin deletion, so at least one other cause exists. Breeds with simpler inheritance have run into gaps like these. Danes, with adult onset and incomplete penetrance, may be harder still, so we would not rely on one DNA test.
What Is Still Open
- Dane-specific reference values and atrial-rhythm criteria for screening.
- How early DCM can appear in a Dane. The studies we read screened adults, the UK study only dogs aged 4 and up, and the youngest affected dog was 13 months old.
- How often occult Danes die suddenly.
- Whether DCM risk follows the X-linked predictions in larger pedigrees, or is autosomal or polygenic.
- How many equivocal Nationals findings later became DCM, and whether age at onset is inherited.
Sources
16 sources
- Summerfield NJ, et al. Efficacy of pimobendan in the prevention of congestive heart failure or sudden death in Doberman Pinschers with preclinical dilated cardiomyopathy (the PROTECT study). J Vet Intern Med 2012;26(6):1337–1349. PMC
- Meurs KM, Miller MW, Wright NA. Clinical features of dilated cardiomyopathy in Great Danes and results of a pedigree analysis: 17 cases (1990–2000). JAVMA 2001;218(5):729–732. AKC Canine Health Foundation summary
- Vezzosi T, et al. Home monitoring of heart rate and heart rhythm with a smartphone-based ECG in dogs. Veterinary Record 2019;184(3):96. PubMed
- U.S. Food and Drug Administration. Update on its investigation of diets and canine dilated cardiomyopathy, February 2019. Summary at dvm360
- NC State College of Veterinary Medicine, Veterinary Cardiac Genetics Laboratory. Great Dane dilated cardiomyopathy study, sample collection and submission. Study page
- Stephenson HM, Fonfara S, López-Alvarez J, Cripps P, Dukes-McEwan J. Screening for dilated cardiomyopathy in Great Danes in the United Kingdom. J Vet Intern Med 2012;26(5):1140–1147. PubMed
- Sisson DD, Thomas WP. Myocardial disease. In: Ettinger SJ, Feldman EC, eds. Textbook of Veterinary Internal Medicine, 4th ed. WB Saunders; 1995:995–1032. (Source of the 3.9% hospital-population figure as cited in Stephenson et al. 2012. We did not read the chapter.)
- Tarducci A, Borgarelli M, Zanatta R, Cagnasso A. Asymptomatic dilated cardiomyopathy in Great Danes: clinical, electrocardiographic, echocardiographic and echo-Doppler features. Vet Res Commun 2003;27(Suppl 1):799–802. PubMed
- AKC Canine Health Foundation grant records for Dr. Kate Meurs: candidate genes for X-linked DCM in the Great Dane and whole-genome sequencing for Great Dane DCM. These are grant summaries, not peer-reviewed papers.
- Kolicheski AL. Detection and characterization of genomic regions associated to dilated cardiomyopathy in Great Danes. Master’s thesis, Swedish University of Agricultural Sciences, Uppsala, 2012. SLU repository
- Meurs KM, Stern JA, Sisson DD, et al. Association of dilated cardiomyopathy with the striatin mutation genotype in boxer dogs. J Vet Intern Med 2013;27(6):1437–1440. PubMed
- University of Pennsylvania PennGen. Juvenile dilated cardiomyopathy test for Portuguese Water Dogs (linked marker). Test listing
- Davis W, Crosland A, Dukes-McEwan J. Canine dilated cardiomyopathy. Part 1: screening, diagnosis and management of preclinical DCM. In Practice 2024;46(9):473–484. Open-access manuscript (CC BY 4.0), publisher. Figure 5 is reproduced from this article.
- Orthopedic Foundation for Animals. Cardiac disease and the Advanced Cardiac Database (procedures and the echocardiogram requirement). ofa.org
- Sunpongsri S, Roos T, Gerhing R, Zandvliet M, Santarelli G. Doxorubicin-induced cardiotoxicity in dogs: a narrative review. Vet Comp Oncol 2026. PubMed
- Great Dane Club of America National Specialty health clinic, cardiology presentation, October 20, 2026. The 1.53% (19 of 1,238) and 3.9% prevalence figures, the year-by-year Nationals results, and the survival estimate come from this seminar.