Heart problems in dogs

Heart problems are most common in older dogs, but sometimes puppies are born with heart defects. Nowadays many effective treatments are available to improve the lives of dogs with heart disease. Outlook is best when treatment starts before serious symptoms develop.

Dogs can have different types of heart disease, and the best treatment will depend on the type and the stage of the condition. Common symptoms of heart disease include coughing, breathing problems and poor energy. These symptoms aren’t usually painful, but as they develop they become increasingly distressing for your dog and for you. Taking your dog for regular health checks means that early signs of disease can be promptly identified and treated. This will help to ensure the best long-term outlook.



What does heart disease in dogs mean?

Heart disease means that your dog’s heart has a problem that affects the way it functions and pumps blood around the body. There are several types of heart problems in dogs.

Degenerative valve disease

Most commonly affecting the mitral valve. Valves are the structures inside the heart that control where and when blood flows. Think of valves like a one-way system for blood flow, In many older dogs, these valves can become misshapen over time and stop working properly. This means blood stops flowing through the heart properly.

Congenital valve diseases

Pulmonic Stenosis or Subaortic Stenosis are examples of congenital valve disease. This is when the valves do not form properly while the puppy is growing in the womb, making it difficult for blood to flow through the heart. This means the heart has to work much harder from birth, leading to heart failure at a very young age.

Other birth defects of the heart

Examples are Patent Ductus Arteriosus and Ventricular Septal Defects. These cause blood to leak between parts of the heart and stop flowing properly.

Dilated cardiomyopathy

The heart gets bigger and the muscle gets weaker, like an overstretched elastic band. The flow of blood gets worse over time. This can sometimes be difficult to spot and even cause sudden death.


The rhythm and sequence of the heartbeat are crucial for proper functioning. Any changes can cause serious problems.

Pericardial disease

Problems in the membrane that involve the heart.

Infections and parasites

Some infections and parasites can affect the heart and blood vessels, but these do not exist in the UK. However, Lungworm is becoming more common, and the damage it causes to the lungs can indirectly lead to heart disease.


Other illnesses such as Pulmonary Hypertension and Chronic Kidney Disease may lead to heart problems.


Symptoms of heart problems in dogs

Early signs of heart disease may be difficult to spot and may only be noticed when a vet listens to your dog’s chest with a stethoscope. This could be a heart murmur, irregular heartbeat or arrhythmia or the heart sounds may be muffled. If the disease is more advanced, you may notice:

  • Getting tired quickly or no longer wanting to run or play
  • Coughing: it can be dry and happen mostly when lying down, or softer or productive in the mornings. It may be more present in the mornings or at night and tends to get worse over time
  • Panting more
  • Fast or laboured breathing
  • Blue or grey gums
  • Fainting, weakness or wobbliness
  • A swollen tummy in some types of heart disease

If your dog’s breathing is laboured, or they appear to be gasping for air, see an emergency vet straight away. Speak to a vet as soon as possible if your dog collapses or faints.



Which dogs are prone to having heart disease?

Heart disease can affect dogs of all types and ages, but some problems are typical of some age groups and are more frequent in some breeds.

  • Mitral valve disease is more common in Cavalier King Charles Spaniels of any age, as well as middle age to older Poodles, Dachshunds, Schnauzers, Chihuahua and most Terrier breeds.
  • Dilated cardiomyopathy is more common in Boxer, Doberman, Great Dane and other large and giant breeds. It usually shows symptoms in middle age.
  • Arrhythmias are more common in breeds like the Boxer, Schnauzer and English Bulldog
  • Birth defects of the heart are more common in the Boxer, German Shepherd, French and English Bulldog, Rottweiler, Golden Retriever, Poodle and Labrador Retriever. Some types can be present from a very young age, others develop later in life.

Dogs rescued from some areas of Southern Europe may be carriers of Heartworm, especially if they spent time as strays. This can be checked with a blood test.


How vets diagnose heart disease in dogs

Heart disease in dogs will lead to death if left untreated, so it is important to take your dog for regular health checks with a vet and discuss any changes to their routine.

During the physical examination, your vet may find heart murmurs, muffled sounds or an abnormal rhythm. In order to determine the cause and severity of the problem, they may suggest:

  • Blood tests
  • Heart scan
  • X-rays
  • ECG
  • Measuring the blood pressure


Vet treatment

Treatments for heart disease in dogs

Choosing the best treatment for a heart problem depends on having an accurate diagnosis and as much information as possible about the problem. If your dog has no symptoms other than a heart murmur, your vet may recommend regular monitoring with heart scans and checkups. Treatment may not be needed until the disease shows signs of progression or new symptoms. At that point, your vet may recommend one or more of the following treatments:

  • Medicine to improve blood supply to the heart itself as well as heart muscle function, called inodilator
  • Medicine to help avoid congestion and lower blood pressure, called ACE inhibitors
  • Diuretics, or water tablets, help remove fluid that is accumulating in the lungs and chest or abdomen
  • Antiarrhythmic medicine, such as calcium channel blockers and beta-blockers, for some types of problems with the heart rhythm
  • Surgery to insert a Pacemaker, for other rhythm problems
  • Congenital heart defects may need advanced surgery to correct the problem. When this is possible, the puppy may make a full recovery.

 Emergency treatment for severe heart disease congestive heart failure)

If your dog is very poorly and struggling to breathe, they might have to stay at a vet clinic for treatment such as:

  • Oxygen: to help vital organs cope with poor blood supply
  • Injectable medications to treat the symptoms
  • Sedation to keep your dog calm and reduce the workload on the struggling heart
  • Chest drainage: to remove fluid around the heart and make breathing easier


Home treatment

How to look after a dog with heart disease at home

If your dog has heart disease, they need ongoing care with a vet. However, there are plenty of things you can do at home to support and monitor your dog with heart disease.

Monitor the resting respiratory rate: count how many breaths your dog takes in one minute when they are sleeping. The normal resting breathing rate in dogs is between 15 and 30 breaths per minute. Do this once daily if your dog has been diagnosed with heart disease, or several times a day if you are worried.

Support your dog’s heart and general health:

  • Give medicines at the doses and times prescribed
  • Prioritise regular check-ups
  • Feed a healthy diet that is appropriate for their condition
  • Maintain healthy body weight
  • Manage exercise: this can be a tricky balance between not letting them overdo it and letting them run as they want.



Tips on how to prevent heart disease in dogs

Much like with people, there are a few things you can do to decrease the risk of your dog developing heart problems:

  • Provide good quality and balanced food throughout their life, appropriate to age and life stage
  • Maintain healthy weight
  • Exercise
  • Attend regular health checks with your vet
  • Avoid breeding dogs if their close relatives have heart problems.
  • Maintain good dental care. Chronic dental disease has been associated with heart problems.
  • Speak to our nurses or vets if you are worried


When to worry

When you should worry about your dog with heart disease

Seek help from a vet in practice straight away if your dog is:

  • Struggling to breathe, open-mouth breathing or gasping for air
  • Developing blue or grey gums or tongue
  • Very tired and you’re struggling to wake them up
  • Collapsed or fainted

Call a vet if:

  • Your dog’s resting respiratory (breathing) rate is consistently above 30 breaths per minute
  • Your dog’s cough is getting worse
  • Your dog’s suddenly less willing or able to play or go for walks

Joii can help with:

  • Looking after your dog with heart disease in a stress-free manner
  • Guidance on how to measure your dog’s resting respiratory rate
  • Checking your dog’s BCS
  • Advice on feeding your dog with heart disease
  • Successfully giving medication to your dog
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