Health
A murmur picked up at the booster, a faint in the park, a cough that comes at night. Heart disease is common from middle age on, and you track it with one simple number.
Caution. Laboured breathing at rest, grey or bluish gums, fainting, coughing up pink froth or a belly that has suddenly swollen: ring straight away or go to an out-of-hours clinic. If the sleeping breathing rate stays above 30 a minute, ring today.
Do not look for the answer in a Facebook group, on TikTok or on a forum. Look for someone trained for this: your dog's own veterinarian, the only person who can examine, investigate and treat them.
Use this page to know what to observe, what to note and what to ask at the appointment, not to treat at home. If you still have doubts after a consultation, ask another vet or a specialist (dermatologist, internist) for a second opinion, not a group. And if you do not have a regular vet yet, find one now, while your dog is healthy: how to choose a veterinary clinic.
At the annual booster the vet put the stethoscope on your dog's chest, paused, listened again and said: "He's got a murmur." He is an eleven-year-old poodle who still takes the stairs on his own, and you had not noticed a thing. Someone else has a six-year-old Dobermann who went down in the park, got up a few seconds later and carried on as if nothing had happened. Someone else lies awake listening to their old dog coughing at night and pacing the house, unable to settle.
Heart disease is common in dogs, especially from middle age on. A lot of it can be kept under control for years if it is caught in time, and much of the monitoring is down to you, at home, with one number written down each evening.
Two conditions account for most cases. In small and medium dogs (Cavalier King Charles spaniels, Chihuahuas, poodles, dachshunds, Yorkies and their crosses), the valve between the two chambers on the left side of the heart thickens with age and stops closing properly. Some blood leaks backwards, and that noise is the murmur your vet hears. In big breeds (Dobermanns, Great Danes, Boxers, Irish Wolfhounds, some shepherd types) it is more often the heart muscle itself: the heart enlarges and pumps weakly, sometimes with rhythm problems that cause fainting or even sudden death. Heart failure is the point where the heart can no longer keep up and fluid starts building in the lungs or the belly.
Ring straight away or head for an out-of-hours clinic if he:
Ring the same day or the next for a new cough that is not going away, tiredness on walks that has crept in over a few weeks, restless nights or weight loss for no reason. Ring then as well if the vet has mentioned a murmur and no tests have been done yet.
This is the most useful number you can collect yourself. Wait until he is deeply asleep, not dreaming and not just back from exercise. Count how many times his chest rises in 30 seconds and double it. Most healthy dogs, and most dogs whose heart disease is well controlled, breathe fewer than 30 times a minute in their sleep, often a lot fewer.
When the number climbs and stays above 30, it can be the first sign of fluid building up in the lungs, often days before any cough. This is exactly what veterinary cardiologists ask owners of dogs with murmurs to do: one number a day, at the same time, written down.
Describe the cough as precisely as you can. When does it come: at night, when he gets excited, after a drink, after exercise? Dry or wet? Some dogs with valve disease cough because the enlarged heart presses on the windpipe, and a cough from fluid on the lungs sounds different. Film it.
On walks, note how many minutes he manages before he stops, whether he sits down mid-walk, whether he refuses the stairs. Comparing with three months ago tells you a lot.
At night, see whether he can lie on his side. A dog who sits or stands with his neck stretched out and keeps moving from spot to spot is showing you that breathing is hard work.
Weigh him once a month. If the muscle over his back and thighs is melting away while his belly gets bigger, write it down and tell the vet.
If he faints, note what he was doing just before, how long it lasted and how he came round. Film it if you can. The vet has to tell a cardiac faint from an epileptic fit, and footage helps a lot.
| Condition | Most often seen in | What you usually notice |
|---|---|---|
| Mitral valve disease (the valve thickens) | Small dogs, middle-aged and older; very common in Cavaliers | Years of just a murmur, then faster breathing, coughing, tiring |
| Heart muscle disease (enlarged, weak heart) | Big breeds: Dobermann, Great Dane, Irish Wolfhound | Tiring, weight loss, fainting, sometimes sudden death with no warning |
| Rhythm problems in Boxers | Boxers, sometimes Bulldogs | Fainting with exercise or excitement |
| Defects present from birth | Puppies and young dogs | A murmur at the first vaccination, slower growth, tiring during play |
| Heartworm | Dogs from mosquito areas | Coughing, tiring on exercise |
Bring your breathing notes to the appointment, any videos of coughing or fainting, and a list of everything he eats, the treats on walks included.
Plenty of dogs with a murmur live for years without a single sign, with a check-up once a year or every six months. Others need daily treatment and more frequent visits and still keep their walks, their games, sometimes even a nose sport at a gentle pace. Following a trail at walking speed is one of the things a dog with a tired heart can keep doing for a long time, with the vet's blessing and no rushing.
Your part is small and it matters a lot. The number written down every evening. Tablets at fixed times. And the phone call to the practice when the number goes up, even if you feel you are bothering them.
What dog owners search for most often on the internet about this problem, with the short answer. The answers are a guide only: the decision belongs to your dog's own vet, after an examination.
That the vet can hear an extra sound made by blood flowing turbulently through the heart. In small, older dogs it usually comes from a thickened valve. A murmur does not automatically mean heart failure: lots of dogs live for years with one and show no signs. A heart scan shows how far the disease has gone and whether treatment is needed.
It depends a great deal on the condition, the stage and how he responds to treatment. Some dogs live for years with a murmur and no signs; once heart failure sets in, the time is usually shorter, from months to a few years. Your own vet can give you an estimate based on the scan and on how his breathing changes.
When he is deeply asleep, count how many times his chest rises in 30 seconds and double it. Write it down every day at the same time. Under 30 a minute is usually fine. If the number climbs and stays above 30, ring the vet: it is often the first sign of fluid building up in the lungs.
Two reasons. An enlarged heart can press on the windpipe and cause a dry cough, especially when he is excited. Fluid on the lungs causes coughing, fast breathing and restless nights. Only the vet can tell them apart, usually with an X-ray, so a new cough in a dog with a murmur needs reporting.
The information on this page is educational and does not replace an examination. For full details and a diagnosis, consult your dog's own veterinarian.
They often come together: the same causes, plans that complement each other.
A goose-honk cough a week after kennels, a night-time cough in an old dog, bursts of sneezing after a field walk. Three sounds, three directions, one first step: film it.
A positive test in a dog who seems perfectly well, a cough after walks, a lump under the skin. Heartworm arrives with mosquitoes and stays hidden for years.
He slept all evening, the room is cool, and now he is panting by the bed. One minute spent counting his sleeping breaths tells you more than any search.
A grey muzzle, longer sleeps, stiff getting up in the morning. An older dog needs closer watching, more frequent check-ups and a home that suits the body he has now.
We work with your dog's behaviour, not its health. For any sign described here, book an appointment with your own vet; the related services page explains how to choose a clinic.