Updated September 25, 2026. Fact-checked against veterinary sources; review by a licensed veterinarian is in progress. See our editorial policy.
Quick answer: Life expectancy for dogs with heart disease varies widely. Many small dogs with a leaky mitral valve live for years before any symptoms, and early treatment with pimobendan can delay heart failure. Once heart failure develops, survival is often measured in months to a year or more with treatment. Large-breed dogs with dilated cardiomyopathy (DCM) often have a shorter outlook. Stage, breed, response to medication, and how early problems are caught all matter.
Mitral valve disease (common in small breeds)
- Murmur only, heart not enlarged (stage B1): many dogs never develop heart failure.
- Murmur with an enlarged heart (stage B2): starting pimobendan delayed heart failure by about 15 months on average in the EPIC trial.
- Heart failure (stage C): with treatment, median survival in a large trial was about 9 months, and many dogs live well beyond a year.
- Hard-to-control heart failure (stage D): the outlook is often months.
Dilated cardiomyopathy (common in large breeds)
- Dogs diagnosed before signs appear may have months to years before heart failure.
- After heart failure develops, survival is often months, though some dogs do better on treatment.
- Dangerous heart rhythms can cause sudden death, so rhythm monitoring matters.
- Some dogs with diet-associated DCM improve after a diet change, based on FDA-investigated cases. Ask your vet.
What improves the outlook
- Early diagnosis: regular checkups, and an echocardiogram when a murmur is found
- Starting medications at the right stage
- Giving medications consistently
- Home monitoring of sleeping breathing rate, which catches worsening early. Many vets advise calling if it’s consistently above about 30–35 breaths per minute.
- Keeping a healthy weight and muscle mass
- Treating other conditions, such as high blood pressure or kidney disease
- Regular rechecks of kidney values and electrolytes on diuretics
Quality of life
As heart disease progresses, focus on comfort: breathing at rest, appetite, energy, and enjoyment of daily life. Your vet can help you track quality of life and discuss options when medications no longer control signs.
Emergency signs
Go to an emergency vet for labored breathing, blue or gray gums, collapse, or a sleeping breathing rate that keeps rising.
What to avoid
- Stopping or changing medications without your vet.
- Salty treats and table scraps.
- Supplements in place of proven treatment.
Frequently asked questions
How long can a dog live with a heart murmur?
Often many years, especially if the heart isn’t enlarged.
How long can a dog live with congestive heart failure?
It varies widely. In a large clinical trial, median survival on pimobendan-based treatment was about 9 months, and many dogs live longer than a year.
Is heart failure painful for dogs?
It causes breathing discomfort and tiredness rather than sharp pain. Treatment aims to keep breathing easy.
Sources
- Keene BW, et al. ACVIM consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs. J Vet Intern Med. 2019
- Boswood A, et al. Effect of pimobendan in dogs with preclinical myxomatous mitral valve disease and cardiomegaly: the EPIC study. J Vet Intern Med. 2016
- Häggström J, et al. Effect of pimobendan or benazepril on survival in dogs with congestive heart failure caused by myxomatous mitral valve disease: the QUEST study. J Vet Intern Med. 2008
- US FDA: Investigation into potential link between certain diets and canine dilated cardiomyopathy
This article is for general education and is not a substitute for care from your own veterinarian. Learn about The Pet Vet and our editorial policy.