Heart disease is one of the health conditions that dogs owners should know about, because it affects quality of life, and it is easier to manage when it is caught early. This guide explains what heart disease is, the signs to watch for, what causes it, how it is diagnosed, how it is treated, whether it can be prevented, and how to live with a dog that has it. Every suggestion here is general guidance, not a prescription for an individual dog.
Senior dogs are the focus of this guide. A dog is usually considered a senior from toy and small breeds from about 10 years, medium breeds from about 8 to 10 years, large breeds from about 7 to 8 years, and giant breeds from about 6 to 7 years, and from that age vet checks should move to twice a year, with weight, teeth, and kidneys checked each time. heart disease is more common in older dogs than in young ones, and it is often harder to spot in a senior, because its signs — stiffness, slowing down, weight loss, confusion — are easily mistaken for normal ageing. The rest of this guide covers the condition itself, with the senior years in mind throughout.
What is heart disease in dogs?
Heart disease is a condition where the heart cannot pump blood around the body as well as it should, so the body does not get the oxygen and nutrients it needs, and fluid can build up in the lungs or the belly. There are many kinds of heart disease: in dogs, the most common is a leaky heart valve, and in cats, the most common is a thickened heart muscle. Heart disease often develops slowly, and a dog can have it for months or years before it shows any signs — which is why a vet listening to the heart at a routine check is so important.
The rest of this guide covers the signs, the causes, how heart disease is diagnosed, how it is treated, whether it can be prevented, and how to live with a dog that has it. A dog with heart disease should be checked by a vet, because the right treatment depends on the individual dog, its age, and how advanced the condition is — and because some of the signs of heart disease can also be signs of other conditions, which need a vet to tell apart. The dog ideal weight calculator works out a target weight range, and the when is a dog considered a senior guide gives the senior thresholds by size.
Signs of heart disease in dogs
The signs of heart disease in dogs are listed below. Not every dog with heart disease will show every sign, and some dogs will show only one or two — but any one of these signs, especially if it lasts more than a few days or gets worse, is worth mentioning to a vet. A dog that is bright, eating, drinking, and otherwise well between episodes is less likely to be seriously ill than a dog that is lethargic, off its food, or losing weight — but the only way to know is to check.
- Coughing, especially at night or after exercise, in dogs.
- Tiring easily, and a dog that stops on walks or in play.
- Breathing faster than usual, or struggling to breathe.
- Fainting or collapsing, especially during excitement or exercise.
- A swollen belly, where fluid has built up.
- Lethargy, weakness, and a dog that seems generally unwell.
- A loss of appetite, and weight loss in advanced disease.
If two or more of those signs apply, or if one sign is severe — a dog that cannot urinate, cannot breathe, cannot stand, or has had a seizure lasting more than five minutes — see a vet the same day. Those are signs that need a vet, not waiting. Bring a note of when the signs started, how often they happen, and what the dog eats and drinks — that information helps the vet far more than a guess about the cause. The how to tell if your dog is overweight guide gives the hands-on check for weight, which matters for many of these conditions.
Causes and risk factors for heart disease
Heart disease has many causes, and they differ between dogs and cats. In dogs, the most common cause is a leaky heart valve, which wears with age and is most common in small and medium breeds. In cats, the most common cause is a thickened heart muscle, which is often inherited — Maine Coon and Ragdoll cats, for example, are prone to it. Some heart disease is present from birth, some is caused by infection or by another condition, and some has no clear cause. Age is the biggest risk factor in dogs, and genes are the biggest in cats.
Some dogs are more prone to heart disease than others, because of their genes, their breed, their size, or their age — but breed and age are not destiny, and a dog of any breed can develop heart disease. What an owner can control is weight, food, exercise, and vet checks: a dog at a healthy weight, with measured food and daily exercise, is less likely to develop heart disease and will cope better with it if it does. A dog that is overweight, that eats a poor diet, or that never sees a vet is more likely to develop heart disease and to have it found late, when it is harder to treat.
How heart disease is diagnosed
A vet diagnoses heart disease by listening to the heart with a stethoscope — a murmur, an irregular rhythm, or a fast rate are the first clues — and then with further tests: an X-ray to see the size of the heart and whether there is fluid in the lungs, and an ultrasound of the heart, which shows how well it is pumping and whether the valves and muscle are normal. A blood test can also help, and the vet may check blood pressure. A dog that is coughing, tiring easily, or breathing fast should be checked promptly.
If you are worried about your dog, see a vet and mention heart disease by name, with the signs you have seen and when they started. Bring a note of what the dog eats, how much, and any medicines it takes, and whether it has had heart disease or a related condition before. A video of the signs, if it is safe to take one, helps the vet far more than a description — especially for seizures, limping, or breathing problems. Do not try to diagnose heart disease yourself, and do not buy medicines or special diets for it without veterinary advice, because the wrong treatment can make it worse.
Treatment and management of heart disease
Treatment depends on the kind and the stage of the disease, but it is usually medicines prescribed by the vet: medicines that help the heart pump better, medicines that remove excess fluid, and medicines that control blood pressure and heart rate. The dog will need regular checks, with the dose adjusted as the disease changes. Diet matters too: a dog with heart disease should be kept at a healthy weight, and the vet may recommend a diet with controlled salt. Exercise should be gentle and regular, not hard or sudden. There is no cure for most heart disease, but treatment can keep the dog comfortable for months or years.
Treatment is a decision made with the vet, weighing the dog's age, health, and quality of life against the treatment and its side effects. Some owners choose not to treat, and to keep the dog comfortable instead — and that is a valid choice, made with the vet, not on the basis of a web page. Whatever is decided, the treatment must be followed every day, at the same times, and the dog must be checked regularly, because heart disease changes over time, and the treatment needs to change with it. Do not stop a medicine suddenly, and do not change the dose without veterinary advice.
Living with a dog with heart disease
A dog with heart disease can live a comfortable life for months or years with the right care, but it needs a routine: medicines at the same times every day, a healthy weight, gentle regular exercise, and regular vet checks. The owner must watch breathing, coughing, and energy, and mention any change to the vet promptly — a dog with heart disease that is breathing fast, coughing a lot, or fainting needs a vet the same day. Keep the dog calm and cool in hot weather, because heat and excitement strain the heart, and know where the nearest emergency vet is.
Keep a routine: the same times for food, medicines, walks, and play, the same places for furniture, food, and water, and a calm, predictable home. Keep a note of appetite, drinking, weight, and behaviour, and mention any change to the vet promptly — a change that lasts more than a few days, or that gets worse, is worth a vet visit. Keep the dog at a healthy weight, with measured food and daily exercise at a level that suits its body, and keep vet checks regular: once a year as an adult, and twice a year as a senior. The senior dog diet guide covers feeding older dogs, and the dog calorie calculator works out daily calories for any weight.
Senior care for a dog with heart disease
A senior dog with heart disease needs more care than a young one: twice-yearly vet checks, a diet review, and attention to weight, teeth, and kidneys. Keep the dog moving every day, at a level that suits its body — shorter, more frequent walks or play sessions, and play that does not strain stiff joints. Give it a warm, supportive bed, ramps or steps instead of jumping, and a predictable routine, with furniture, food, and water in the same places. Mention any change to your vet promptly, because a senior dog that suddenly gets worse may have a new problem, not just a bad day.
Can heart disease be prevented?
Heart disease cannot always be prevented, because much of it is about age and genes — but the risk can be reduced. Keep the dog at a healthy weight, because extra weight makes the heart work harder, and keep its teeth clean, because dental disease is linked to heart disease. If you are buying a puppy of a breed that is prone to heart disease, ask what heart screening the parents had. Have the dog checked regularly, so a murmur is found early, when treatment works best — a murmur found at a routine check is far better than heart disease found when the dog is already struggling to breathe.
Early checks matter most: have the dog checked regularly, so heart disease is found early, when treatment works best. Keep the dog at a healthy weight, with measured food and daily exercise, and mention any change in drinking, eating, weight, or behaviour to your vet early, because a change caught early is easier to treat than one left for weeks.
For related reading, see the dog ideal weight calculator, the dog body condition score chart, the how to tell if your dog is overweight guide, the senior dog diet guide, the dog calorie calculator, the when is a dog considered a senior guide.
Frequently asked questions
What is heart disease in dogs?
Heart disease is a condition where the heart cannot pump blood around the body as well as it should, so the body does not get the oxygen and nutrients it needs, and fluid can build up in the lungs or the belly. There are many kinds of heart disease: in dogs, the most common is a leaky heart valve, and in cats, the most common is a thickened heart muscle. Heart disease often develops slowly, and a dog can have it for months or years before it shows any signs — which is why a vet listening to the heart at a routine check is so important.
What are the signs of heart disease in dogs?
The most common signs are: Coughing, especially at night or after exercise, in dogs. Tiring easily, and a dog that stops on walks or in play. Breathing faster than usual, or struggling to breathe. See the full list above for every sign to watch for, and see a vet promptly if two or more apply, or if one sign is severe.
What causes heart disease in dogs?
Heart disease has many causes, and they differ between dogs and cats. In dogs, the most common cause is a leaky heart valve, which wears with age and is most common in small and medium breeds. In cats, the most common cause is a thickened heart muscle, which is often inherited — Maine Coon and Ragdoll cats, for example, are prone to it. Some heart disease is present from birth, some is caused by infection or by another condition, and some has no clear cause. Age is the biggest risk factor in dogs, and genes are the biggest in cats.
How is heart disease diagnosed?
A vet diagnoses heart disease by listening to the heart with a stethoscope — a murmur, an irregular rhythm, or a fast rate are the first clues — and then with further tests: an X-ray to see the size of the heart and whether there is fluid in the lungs, and an ultrasound of the heart, which shows how well it is pumping and whether the valves and muscle are normal. A blood test can also help, and the vet may check blood pressure. A dog that is coughing, tiring easily, or breathing fast should be checked promptly.
How is heart disease treated?
Treatment depends on the kind and the stage of the disease, but it is usually medicines prescribed by the vet: medicines that help the heart pump better, medicines that remove excess fluid, and medicines that control blood pressure and heart rate. The dog will need regular checks, with the dose adjusted as the disease changes. Diet matters too: a dog with heart disease should be kept at a healthy weight, and the vet may recommend a diet with controlled salt. Exercise should be gentle and regular, not hard or sudden. There is no cure for most heart disease, but treatment can keep the dog comfortable for months or years.
When should a dog with heart disease see a vet?
See a vet promptly if the dog shows any of the signs above, especially if they last more than a few days or get worse — and the same day if the dog cannot urinate, cannot breathe, cannot stand, has had a seizure lasting more than five minutes, or is lethargic or off its food. Bring a note of when the signs started and what the dog eats and drinks. A dog with heart disease should be checked by a vet, because the right treatment depends on the individual dog, its age, and how advanced the condition is.
Results on this page are estimates for general information only and are not veterinary advice. If your pet is ill, underweight, overweight, pregnant, or has a health condition, consult your veterinarian before changing diet or care.