Dog Health
Heart Disease in Dogs UK — Symptoms, Breeds & When to See a Vet
Published Last updated 3 min read
Quick answer
Heart disease is common in older UK dogs — especially small breeds like Cavalier King Charles Spaniels. Warning signs include coughing, tiring on walks, and breathlessness at rest. Early vet diagnosis and medication can significantly improve quality of life.
What is heart disease in dogs?
Heart disease means the heart cannot pump blood efficiently. In UK dogs, the most common forms include:
- Mitral valve disease (MVD) — leaky heart valve; very common in small breeds
- Dilated cardiomyopathy (DCM) — weakened heart muscle; seen in Dobermanns, Boxers, and some large breeds
- Congenital defects — present from birth in some puppies
Heart disease is different from heartworm — a parasite spread by mosquitoes, rare in native UK dogs. See Heartworm vs lungworm.
Symptoms to watch for
According to the PDSA and Blue Cross, signs often develop gradually:
| Symptom | What it may mean |
|---|---|
| Coughing | Especially at night or after lying down — see Why is my dog coughing? |
| Exercise intolerance | Stopping on walks that used to be easy |
| Resting breathlessness | Fast breathing when asleep — see Why is my dog panting heavily? |
| Reduced appetite & weight loss | See Unexplained weight loss |
| Fainting or collapse | Reduced blood flow to brain |
| Swollen belly | Fluid accumulation (ascites) from heart failure |
| Pale or blue gums | Emergency — insufficient oxygen |
Dogs may hide early illness — subtle slowing on walks is often the first sign owners notice.
Breeds at higher risk
| Breed / type | Common concern |
|---|---|
| Cavalier King Charles Spaniel | Mitral valve disease — very prevalent |
| Dobermann, Boxer | Dilated cardiomyopathy |
| Older small breeds | MVD with age |
| Giant breeds | Some cardiomyopathies |
Screening programmes exist for some breeds — ask your vet if your breed is at risk.
How heart disease is diagnosed
Your vet may use:
- Stethoscope — heart murmurs and rhythm abnormalities
- Chest X-rays — heart size and lung fluid
- Echocardiogram (heart scan) — gold standard for valve and muscle function
- ECG and blood tests — including cardiac biomarkers (NT-proBNP)
- Blood pressure — in some cases
Many murmurs are detected at routine annual checks before dogs show symptoms — early monitoring helps.
Treatment and management
Treatment depends on the type and stage:
- Daily medication — diuretics, ACE inhibitors, pimobendan, and others as prescribed
- Low-salt diet — sometimes recommended
- Controlled exercise — maintain fitness without overexertion
- Regular rechecks — medication doses adjusted over time
Heart disease is usually managed rather than cured — but many dogs live good-quality lives for years with treatment.
When to seek emergency care
Go to an emergency vet immediately for:
- Collapse or fainting
- Severe breathing difficulty or open-mouth distress in a dog that does not normally pant like this
- Blue or grey gums
- Sudden abdominal swelling with weakness
Prevention and monitoring
- Annual health checks — stethoscope exam catches murmurs early
- Dental care — dental disease links to heart health via bacteria
- Healthy weight — obesity strains the heart
- Breed screening where recommended
Related guides
Sources & further reading
Facts in this guide are rewritten in plain English from publicly available UK advice. We name the organisation where a specific point comes from their guidance. Links below go to the original pages — use them to read the source material directly.
PETHEALTH+ is independent. These organisations do not sponsor, approve, or partner with this website. Guidance checked against sources listed below (last updated 2026-06-25).
Related guides
- Heartworm vs Lungworm in Dogs UK — How to Tell Them Apart
- Why Is My Dog Coughing? Common Causes & When to Worry
- Why Is My Dog Panting Heavily? UK Heat, Pain & Emergency Signs
- Unexplained Weight Loss in Dogs: UK Causes & When to Worry
- Dog Dental Care UK — Brushing, Gum Disease & Vet Checks
- Dog Obesity UK — Body Condition, Diet & Safe Weight Loss
Frequently Asked Questions
- What are signs of heart disease in dogs?
- Coughing (especially at night or after rest), tiring easily on walks, resting breathlessness, reduced appetite, weight loss, and fainting. A swollen belly may indicate fluid accumulation.
- Which dog breeds get heart disease?
- Cavalier King Charles Spaniels are prone to mitral valve disease. Dobermanns and Boxers can develop dilated cardiomyopathy. Any breed can develop heart problems — especially with age.
- Is heart disease in dogs treatable?
- Many forms can be managed with lifelong medication, diet, and exercise modification — improving quality of life. Early diagnosis before severe symptoms helps most.
- When is heart disease an emergency?
- Collapse, blue or grey gums, severe breathing difficulty, or sudden abdominal swelling need emergency veterinary care.