By Dial A Vet Veterinary Team
The single most useful thing an owner of a dog with heart disease can learn is how to count breaths while their dog sleeps. A rising sleeping breathing rate is often the earliest sign that fluid is building up in the lungs, days before the cough, restlessness, and breathlessness that make congestive heart failure obvious. In Australia, most cases come from mitral valve disease in small breeds such as Cavalier King Charles spaniels and from dilated cardiomyopathy in large breeds such as Dobermans. Heart failure cannot be cured, but with medicine and careful monitoring many dogs enjoy good quality time. This guide explains the signs, triage, and how vets manage it.
Key takeaways
- Congestive heart failure (CHF) means the heart cannot keep up, so fluid builds up in the lungs or abdomen.
- Count your dog's sleeping breathing rate. Most healthy dogs breathe fewer than 30 times a minute while asleep. A rate that is consistently above that, or rising, needs a call to your vet.
- Laboured breathing at rest, blue or grey gums, or collapse are emergencies.
- Diagnosis uses a physical exam, chest X-rays, and heart ultrasound.
- Never change or stop heart medicines without your vet.
Common causes
- Myxomatous mitral valve disease (MMVD): a leaky heart valve, very common in older small-breed dogs. It usually starts as a murmur long before failure.
- Dilated cardiomyopathy (DCM): weak, enlarged heart muscle, seen in Dobermans, Great Danes, Boxers, and others. Some cases have been linked to certain diets, which is still being studied.
- Congenital heart defects in young dogs.
- Heartworm disease in unprotected dogs.
- Heart rhythm problems that reduce pumping efficiency.
Signs of heart failure
- Faster breathing at rest or during sleep
- Coughing, often at night or after lying down
- Restlessness at night, reluctance to lie flat
- Tiring quickly on walks
- Fainting or collapse during excitement or exercise
- Swollen belly from fluid (more common with right-sided failure)
- Weight loss and muscle wasting over time
- Reduced appetite
How to count sleeping breaths
- Wait until your dog is deeply asleep in a cool room, not dreaming.
- Count each rise and fall of the chest as one breath for 30 seconds, then double it.
- Record it daily in a notebook or app.
- Tell your vet if the rate climbs above the target they set for your dog, or rises steadily over several days.
When to see a vet
Emergency, go now: struggling to breathe, breathing with the mouth open while resting, extending the neck to breathe, blue, grey, or pale gums, collapse, coughing up pink froth, or a sleeping breathing rate far above normal.
Same day: a sleeping breathing rate consistently above your vet's target, a new or worse cough, fainting that has recovered, or a swelling belly.
Book a visit: a newly detected murmur, gradual tiredness, or weight changes in a dog with known heart disease.
How vets typically diagnose and treat
Diagnosis usually involves listening to the heart and lungs, chest X-rays to look for fluid and heart size, and an echocardiogram (heart ultrasound). Blood tests, blood pressure, an ECG, and a blood marker of heart strain help complete the picture.
Emergency treatment focuses on oxygen and medicines that remove fluid from the lungs. Long-term management usually includes a combination of medicines that remove fluid, support the heart's pumping, and reduce strain on the heart. Your vet decides which medicines your dog needs, and the plan is adjusted over time based on breathing rates, rechecks, and kidney blood tests. For some dogs with mitral valve disease and an enlarged heart, starting treatment before signs of failure can delay their onset.
Living with a dog with heart failure
- Give medicines exactly as directed and keep a supply on hand.
- Keep up sleeping breathing rate records.
- Let your dog set the pace on walks and avoid exercise in hot weather.
- Ask your vet about diet, including salt intake and whether a heart diet suits your dog.
- Keep your dog at a healthy weight, while watching for muscle loss.
- Prevent heartworm with a year-round product.
FAQ
How long can a dog live with congestive heart failure?
It varies widely with the cause, how early it is caught, and response to treatment. Many dogs live months to a year or more with good quality of life. Your vet can give a more personal outlook.
Does a heart murmur mean my dog has heart failure?
No. A murmur is a sound caused by turbulent blood flow. Many dogs with murmurs never develop failure, but they should be monitored. Read more in heart disease in dogs.
Can I give my dog extra medicine if breathing gets worse?
Only if your vet has given you a specific written plan for this. Otherwise, call your vet or go to an emergency clinic.
Is coughing always due to the heart?
No. Airway problems such as tracheal collapse are common in the same small breeds. Your vet can tell them apart.
Talk with a vet
Between rechecks, a vet at Dial A Vet can review breathing rate records and help you decide whether a change needs attention. If your dog is struggling to breathe, go straight to an emergency clinic. More on end-stage signs is in heart failure in dogs.
References
- American College of Veterinary Internal Medicine (ACVIM). Consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs.
- Merck Veterinary Manual. Heart failure in dogs and cats.
- Cardiac Education Group. Resting respiratory rate resources for owners.
- U.S. Food and Drug Administration. Investigation into diet and canine dilated cardiomyopathy.
- American Heartworm Society. Heartworm prevention.
Disclaimer: Educational only. This page does not replace an examination by a veterinarian. Breathing difficulty at rest is an emergency. Never adjust heart medicines without veterinary advice.