Congestive Heart Failure in Dogs
Congestive heart failure (CHF) happens when a diseased heart can no longer pump well enough, so blood backs up and fluid leaks out – most often into the lungs, which makes breathing hard. It is serious and it is progressive, but with the right treatment many dogs still have meaningful, comfortable time and feel like themselves again.
Quick answer
For owners, the most useful home warning sign is your dog’s resting or sleeping breathing rate. If it keeps climbing above about 30 breaths per minute, or your dog is coughing more, tiring easily, or breathing harder at rest, call your veterinarian. Labored breathing, collapse, or pale, grey, or bluish gums should be treated as an emergency.
Symptoms of heart failure in dogs
- Coughing and faster or harder breathing, especially at rest or when lying down
- A resting breathing rate over ~30 breaths per minute (a key early warning)
- Tiring easily, reluctance to exercise, sudden weakness, wobbliness, fainting, or collapse
- A swollen belly (fluid), restlessness at night, or pale/bluish gums (urgent)
The ACVIM stages of heart disease (used mainly for mitral valve disease)
Cardiologists use a staging system, developed for the common mitral valve disease, so treatment can be matched to where the dog is:
| Stage | What it means |
|---|---|
| A | At risk for heart disease, but no known structural heart disease yet. |
| B1 | Structural heart disease is present, often first noticed as a murmur in dogs with valve disease, but there are no symptoms and no meaningful enlargement. |
| B2 | Heart disease with measurable enlargement, still no symptoms. In dogs with mitral valve disease that meet B2 criteria, pimobendan is commonly started to delay the onset of heart failure. |
| C | Heart failure – the dog has, or has had, symptoms (coughing, fluid, breathing trouble). Treated with several medications. |
| D | End-stage heart failure that no longer responds well to standard treatment. |
Life expectancy by stage
Every dog is different, and your veterinarian or cardiologist can give your dog’s outlook – but as general guidance: dogs in Stage B2 often have a year or more before heart failure begins, and starting medication at this stage can extend that time. Once a dog reaches Stage C (active heart failure), survival varies widely. Many references put it broadly in the range of about 6 to 14 months, and some dogs live longer with a good response to treatment. Stage D is measured in weeks to months. These are averages, not predictions – response to treatment, the underlying cause, and overall health all shift the picture.
How heart failure is treated
Treatment is directed by your vet and usually combines several medications:
- Pimobendan (Vetmedin) – helps the heart pump more effectively and eases its workload.
- Furosemide (a diuretic) – clears the fluid backing up in the lungs.
- An ACE inhibitor (such as enalapril or benazepril) and often spironolactone – protect and unload the heart.
Alongside medication, a lower-sodium diet, a healthy weight, sensible rest, and daily breathing-rate monitoring all help. Heart-support nutrients (such as taurine, L-carnitine, CoQ10, and omega-3s) may support normal heart function as part of the plan – see our heart supplements guide – but they support, and never replace, your vet’s treatment.
Coughing, weakness, and collapse
Coughing in CHF usually comes from fluid in the lungs or an enlarged heart pressing on the airway, so a worsening cough means call your vet. Sudden weakness, fainting, or collapse can happen when the heart cannot deliver enough blood, though these signs have other causes too, so any of them warrants prompt veterinary attention.
Monitoring at home
Count your dog’s resting or sleeping breathing rate a few times a week. Staying under about 30 breaths per minute is reassuring; a steady climb above 30-40 is often the first sign of fluid returning – call your vet early, before it becomes a crisis.
Comfort, quality of life, and knowing when it’s time
Most dogs with CHF have many good days ahead with treatment. For guidance on keeping a dog comfortable in advanced heart failure – and on the hardest decision of all – see our compassionate guide to heart failure and end-of-life care.
When it’s an emergency
Go to a veterinarian or emergency clinic immediately for labored or open-mouth breathing, a resting breathing rate that won’t come down, collapse, or blue/grey gums. These signs can mean fluid is returning to the lungs or that another serious breathing problem is present.
When management stops being enough, our end-of-life guide covers the hardest decisions, and heart medications explains the drugs your vet may use.
References and further reading
- American College of Veterinary Internal Medicine (ACVIM). 2019 consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs. Journal of Veterinary Internal Medicine.
- Merck Veterinary Manual (MSD Manual). Heart disease and heart failure in dogs.
- U.S. Food and Drug Administration. Questions and answers: FDA’s work on potential causes of non-hereditary DCM in dogs (fda.gov).
Frequently asked questions
What are the ACVIM stages of heart disease in dogs?
ACVIM stages A-D describe the progression of heart disease. Stages A, B1, and B2 come before congestive heart failure; Stage C means the dog has, or has had, heart failure; and Stage D is advanced heart failure that no longer responds well to standard treatment.
How long can a dog live with congestive heart failure?
It varies. Survival after heart failure begins varies widely, with many references citing roughly 6 to 14 months and some dogs living longer; earlier stages can be years. Your vet can give your dog’s outlook.
Is congestive heart failure in dogs painful?
CHF itself isn’t thought to be painful, but the breathlessness can be distressing – which is exactly what the medications relieve. Most treated dogs are comfortable.
What is the best treatment for CHF in dogs?
A combination set by your vet – typically pimobendan plus a diuretic, often with an ACE inhibitor and spironolactone, alongside a low-sodium diet and home monitoring.
How do I know if my dog’s heart failure is getting worse?
A rising resting breathing rate, a new or worse cough, less energy, fainting, or a swollen belly. Monitoring the resting breathing rate catches many flare-ups early.
What is the difference between left-sided and right-sided heart failure?
Left-sided failure backs fluid up into the lungs, causing coughing and breathing trouble. Right-sided failure backs fluid up into the body, causing a swollen belly or limb swelling. Many dogs have mainly left-sided failure, and some have both.
What should I monitor at home with heart failure?
The resting breathing rate is the most useful number. Also watch appetite, energy, coughing, and how much your dog drinks, and tell your vet about any clear change, especially a rising breathing rate.
Can I adjust my dog’s furosemide dose myself?
No. Diuretic doses are balanced carefully against the kidneys and hydration. Do not change furosemide or any heart medication without your vet, even if signs change. Call them instead.
This guide is educational and is not a substitute for veterinary diagnosis or care. Heart failure needs veterinary treatment – if your dog is struggling to breathe, seek emergency care.
This guide is educational and is not a substitute for veterinary diagnosis or care. If your dog has signs of heart trouble, talk to your veterinarian.