By Dial A Vet Veterinary Team
Heart failure means the heart can no longer keep up with the body's needs without help. For dogs it is usually the late stage of a longer story, most often mitral valve disease or dilated cardiomyopathy. A diagnosis is serious, but many dogs live good-quality months, and sometimes years, once treatment is tuned to them. The most useful thing an owner can do is learn what to watch at home. For background on the underlying conditions, see common types of heart disease in dogs. For how fluid builds up and why breathing changes, see what congestive heart failure is.
Key takeaways
- Heart failure is a stage, not a single disease. It follows conditions such as mitral valve disease and DCM.
- Vets often use the ACVIM staging system (A to D) to describe where a dog is and to time treatment.
- Counting your dog's breathing rate while asleep is one of the best early warning tools at home.
- Medication plans are adjusted over time. Do not change or stop doses without talking to your vet.
- Laboured breathing, blue or grey gums, or collapse need emergency care immediately.
The stages of heart disease and failure
The American College of Veterinary Internal Medicine (ACVIM) staging system, first written for mitral valve disease, is widely used to explain progress:
- Stage A: dogs at higher risk (for example, Cavaliers) with no heart changes yet.
- Stage B1: a murmur or valve change but no meaningful heart enlargement.
- Stage B2: heart enlargement without signs of failure. Some dogs benefit from starting medication here.
- Stage C: current or past signs of heart failure, such as fluid on the lungs.
- Stage D: heart failure that is becoming hard to control with standard treatment.
Knowing the stage helps you understand why your vet is suggesting a particular test or timing, and what changes to expect.
Signs of heart failure
- Faster breathing at rest or during sleep
- Coughing, restlessness at night, or sleeping sitting up
- Exercise intolerance, tiring after a short walk
- Reduced appetite and weight or muscle loss
- A swollen, fluid-filled belly (more often with right-sided failure)
- Fainting, weakness, or pale gums
The sleeping breathing rate check
Many cardiologists ask owners to count breaths when the dog is soundly asleep in a cool, calm room. Count each rise of the chest for 30 seconds and double it. Write the number down with the date. Your vet will tell you what range is normal for your dog and the number at which you should call. A steady upward trend over several days is often the first sign that fluid is building, sometimes before coughing or tiredness. Free phone apps can make the count easier, but a watch works fine.
When it is an emergency
Go to an emergency veterinary hospital straight away if your dog:
- Is breathing hard, fast, or with an open mouth while resting
- Has blue, grey, or very pale gums
- Cannot lie down comfortably and keeps standing with elbows out and neck stretched
- Collapses, faints, or is suddenly very weak
- Coughs up frothy or pink-tinged fluid
Keep your dog calm and cool during transport. Avoid pressure on the chest.
How vets diagnose and treat heart failure
Chest X-rays show the heart size and whether fluid is in or around the lungs. An echocardiogram shows the structure and pumping of the heart, and an ECG checks rhythm. Blood tests look at kidney function and electrolytes, which matter because heart medications affect them.
In hospital, a dog in active failure may need oxygen, medication to clear fluid, and rest. At home, long-term plans commonly combine medications that remove excess fluid, support how strongly the heart pumps, and reduce strain on the heart. The specific choices, doses, and timing are set and adjusted by your vet or a cardiologist, often after repeat blood tests. Draining fluid from the belly or chest is sometimes needed.
Living well with heart failure
- Give medications exactly as prescribed and keep a written schedule. Missed doses can tip a stable dog into crisis.
- Keep up the sleeping breathing rate record and bring it to check-ups.
- Offer gentle, regular exercise your dog enjoys, and stop when they want to stop.
- Avoid salty treats and table scraps. Ask your vet whether a diet change is useful.
- Watch appetite and weight. Muscle loss is common and worth raising early.
- Keep your dog cool in Australian summers. Heat and humidity make breathing harder.
- Plan ahead with your vet for quality of life decisions so you are not making them in a crisis.
FAQ
How long can a dog live with heart failure?
It varies a lot with the cause, how quickly treatment starts, and how the dog responds. Some dogs do well for a year or more. Your vet can give a more personal outlook after tests.
Is heart failure painful for dogs?
Heart failure itself is not usually described as painful, but breathlessness is distressing. Good control of fluid and breathing is the main comfort goal.
Can my dog still go for walks?
Most dogs with stable heart failure benefit from short, gentle walks. Avoid hard exercise and hot weather, and follow your vet's advice.
Talk with a vet
If your dog's sleeping breathing rate is creeping up, or you want help understanding a new diagnosis, our vets can talk it through by video. Book a consult at dialavet.com. If your dog is struggling to breathe or has collapsed, go to your nearest emergency vet hospital now.
References
- Keene BW, et al. ACVIM consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs. Journal of Veterinary Internal Medicine, 2019.
- Merck Veterinary Manual. Heart Failure in Dogs and Cats.
- VCA Animal Hospitals. Congestive Heart Failure in Dogs.
Disclaimer: Educational only. This page does not replace an examination or advice from your own veterinarian. If your pet is having trouble breathing or has collapsed, contact a veterinary hospital immediately.