Most Common Canine Heart Diseases
| Breed | Common Heart Condition | Age at Onset | Screening |
|---|---|---|---|
| Cavalier King Charles Spaniel | MVD (mitral valve disease) | 5+ years | Annual cardiac auscultation |
| Doberman Pinscher | DCM (dilated cardiomyopathy) | 6+ years | Echocardiogram + Holter |
| Boxer | ARVC (arrhythmogenic RV cardiomyopathy) | 6+ years | Holter monitor |
| Great Dane | DCM | 4+ years | Echocardiogram annually |
| Cocker Spaniel | MVD | 7+ years | Annual auscultation |
| Golden Retriever | Subvalvular aortic stenosis | Puppy | Breeding screen |
Chronic Valvular Disease Progression
Heart Health Checklist for Dogs
| Do | Annual veterinary auscultation (listen to heart) |
| Do | Echocardiogram for predisposed breeds by age 5 |
| Do | Monitor for cough, especially at night or after exercise |
| Do | Track exercise tolerance — decreased stamina is a red flag |
| Do | Weigh monthly — sudden weight loss or gain signals fluid shifts |
| Do | Watch for fainting or collapsing episodes (syncope) |
| Do | Start pimobendan early for Stage B2 MVD (extends life by 15 months) |
| Avoid | Wait until coughing starts before taking heart disease seriously |
| Avoid | Skip echocardiograms if no murmur is heard |
| Avoid | Assume labored breathing means the dog is 'just hot' |
Heart Disease in Dogs: DCM, Valve Disease, and What to Watch For
Canine heart disease is more common than most owners realize — an estimated 10% of dogs have some form of cardiac condition, rising steeply in dogs over age 8. The encouraging reality is that modern cardiology can extend quality life significantly when disease is caught early.
This article is educational. Only your veterinarian can diagnose heart disease; symptoms described here should prompt a vet visit, not home treatment.
| Type | What Happens | Breeds Most Affected |
|---|---|---|
| Myxomatous Mitral Valve Disease (MMVD) | Mitral valve degenerates, blood leaks back; most common form (~80% of canine heart disease) | Cavalier King Charles Spaniels, Dachshunds, small breeds |
| Dilated Cardiomyopathy (DCM) | Heart muscle weakens, chambers dilate, pumping efficiency drops | Dobermans, Great Danes, Boxers, Cocker Spaniels |
Warning Signs to Know
Early heart disease is often silent — detected only through a murmur on a routine exam. As the condition progresses, watch for: coughing (especially at night or first thing in the morning), labored breathing, rapid breathing at rest (resting respiratory rate above 30 breaths per minute is a warning sign owners can track at home), exercise intolerance, and fainting or collapse. Call your vet immediately if you observe breathing difficulty or collapse.
Diagnosis and Staging
Your vet will listen for a murmur, then may recommend chest X-rays (to evaluate heart size and check for fluid in the lungs), an echocardiogram (ultrasound of the heart to assess chamber size and function), and an ECG for arrhythmia detection. The ACVIM staging system (A through D) guides treatment decisions based on heart size and symptom status.
Treatment
The landmark EPIC trial (2016) demonstrated that pimobendan started before symptoms in MMVD dogs with enlarged hearts significantly delayed the onset of heart failure. ACE inhibitors and diuretics are added as disease progresses. DCM management depends on whether arrhythmias are present and the degree of dysfunction. All treatment decisions should be made with a veterinary cardiologist where possible.
Frequently Asked Questions
What are early signs of heart disease in dogs?
Early signs include exercise intolerance (tiring more quickly), occasional coughing (especially at night or after lying down), increased respiratory rate at rest, and reduced stamina. A heart murmur detected during a routine exam is often the first finding.
What is DCM in dogs?
Dilated cardiomyopathy (DCM) is a disease where the heart muscle weakens and the chambers enlarge, reducing pumping efficiency. It is most common in large and giant breeds including Dobermans, Great Danes, Boxers, and Cocker Spaniels.
Can dogs live a long time with heart disease?
Yes. Many dogs with early-stage heart disease live years with appropriate monitoring and, when indicated, medication. The EPIC trial showed that starting medication before symptoms develop in dogs with advanced valve disease significantly delayed the onset of heart failure.