Heart Failure in Dogs (Heart Disease)

Just like humans, dogs can also suffer from heart problems, especially as they get older. In fact, heart failure is a very common condition in dogs, and catching it early is essential.

The causes and symptoms of heart disease vary widely. Let's take a detailed look at everything you need to know about its origins, symptoms, diagnosis, and treatment.

What is heart disease?

Heart conditions come in many forms — let's give a brief overview so you can better understand how your pet's heart beats and when you should see a specialist.

The heart is a hollow, muscular organ. It's divided into 4 chambers (two atria and 2 ventricles). The atria connect to the ventricles through valves.

This gives us the following causes of heart disease:

• Disorders in the production and conduction of electrical impulses. Arrhythmias.
• Valve disorders, which can be of two types: when a valve lets blood leak back through, it's called insufficiency (or regurgitation); when it blocks blood flow, it's known as stenosis.

Heart failure refers to an organ's inability — in this case the heart's — to carry out the functions needed for the body to work normally. So, a heart in failure isn't able to pump enough blood to the whole body.

Dogs can suffer from various heart diseases, which fall into either congenital or age-acquired categories. As time passes, the heart condition usually gets worse, leading to greater complications that put the dog's life at risk.

Risk factors

Dogs that meet one or more of the following characteristics are more likely to develop heart disease:

• Dogs with a genetic history of heart problems.
• Certain breeds, such as: Mastiff, Boxer, Doberman, Cocker Spaniel, Bull Terrier, Dalmatian, Great Dane, Saint Bernard, and Giant Schnauzer.
• Older dogs. If your dog is already over 7 years old, they're quite likely to have some heart problems. Generally speaking, all senior dogs have some degree of heart disease. Likewise, larger dogs, since they age at a faster rate, tend to develop these conditions earlier.
• Small dogs. Toy-sized dogs aren't exempt either, as they're more prone to heart valve degeneration and endocardiosis.

Symptoms of heart disease in dogs

It's important to recognize the signs below and see the vet as soon as we notice any of them in our dog. In most cases, the earlier a condition is diagnosed, the better the prognosis.

Arrhythmias

One of the main symptoms is arrhythmia. A dog with arrhythmia has irregular heartbeats, which can be caused by many factors. Assessment by a specialist is essential to determine the state of the organ.

Weakness, excessive tiredness, and even reluctance to exercise

This symptom is especially noticeable after physical exertion or simply after their daily walks. A healthy dog used to a routine shouldn't show this symptom. If you notice your dog is exhausted after their usual routine, it's best to visit the vet.

Frequent or chronic coughing

If your dog coughs often, especially at night or after resting, ask your vet about it — it could be a cardiac cough.

• Other conditions related to coughing in dogs

Elevated heart rate and blood pressure

To catch these symptoms, it's important to have our furry friend get regular veterinary check-ups.

Breathing difficulties

This is one of the most common and noticeable symptoms. A dog with cardiovascular problems will show breathing issues, such as difficulty breathing, panting, and frequent wheezing, along with rapid breathing.

Grayish or bluish coloring of the gums and tongue

These parts of the mouth can warn us of many problems a dog may be experiencing, such as poisoning, anemia, and, in this case, heart disease.

Weight and/or appetite loss

If our dog is keeping to their usual diet and isn't affected by other factors like a rise in temperature or stressful moments, weight and/or appetite loss is a clear warning sign of illness that should alarm us.

Abdominal swelling

Another sign we might notice is swelling in our dog's belly area, from fluid buildup in the abdomen (edema).

Fainting

Since the heart can't pump blood effectively to every part of the body, blood flow can't reach all areas properly, including the brain. This causes not only weakness but also frequent fainting spells.

Vomiting

Although this symptom is also very common in other diseases, a dog that regularly regurgitates bile may have a heart problem, from circulatory congestion around the liver and gallbladder.

Other symptoms associated with heart failure

• Heart murmurs
• Slow heart rate
• Collapse
• Weight gain
• Heatstroke
• Apathy
• Lethargy
• Marked restlessness, especially at night
• Mood changes

Any of these symptoms appearing suddenly should be reason enough to visit the vet. That said, we shouldn't panic prematurely, since they can also be signs of aging or other conditions.

Cardiovascular diseases in dogs

Heart attacks, infections, or heart tumors are quite rare. However, there are some other heart conditions that are very common among dogs.

Canine heartworm disease

Heartworm disease is a very serious condition caused by a mosquito bite. When bitten, worm larvae enter the dog's body and reproduce in the dog's heart and lungs, causing an obstructive effect — the symptoms depend on where they settle, whether respiratory or affecting general circulation.

Pericarditis

The pericardium is the double membrane that covers the heart. Pericarditis is the name for inflammation of the pericardium. With this disease, this membrane sometimes stores more fluid than normal, causing pressure, swelling, and inflammation, which produces sudden, sharp pain in the area.

Dilated cardiomyopathy

When a dog is diagnosed with dilated cardiomyopathy, the walls of the heart muscle are unable to contract forcefully. This leads to a buildup of pressure and blood volume, and the subsequent dilation of the muscle.

• Symptoms of dilated cardiomyopathy in dogs

Endocarditis

The valves are what's affected in this disease. After becoming infected by a microorganism, bacteria form growths inside the dog's blood vessels.

Cardiac hypertrophy can also occur as a result of heart disease. In this case, the muscular walls thicken in response to increased cardiac workload.

Valvular endocardiosis

This age-related condition causes the progressive deterioration of the heart valves.

How to prevent heart disease

Here are some tips for preventing heart problems. Even in congenital heart conditions, where the dysfunction is already present, these tips will still help you look after your dog and improve their quality of life.

• Being overweight raises the risk of heart problems — follow a balanced, quality diet, especially for older dogs.
• Regular, moderate physical activity, around 30 minutes per walk. In summer, remember to walk during the coolest hours of the day.
• Avoid treats/snacks.
• Use a harness on walks and avoid collars.
• If your dog is diagnosed with heart failure, the leash should be kept as short as possible (to avoid breathing difficulty from running).

Besides following the tips above, it's essential to visit the vet as soon as we notice symptoms of heart disease. The professional will run the appropriate tests, such as an electrocardiogram, and prescribe the most suitable treatment.

If it turns out your friend does have heart disease, the treatment will likely be lifelong. They'll also need regular check-ups to monitor how the disease progresses.

Bibliography Carlson and Giffin (2002): Manual práctico de veterinaria canina. Madrid: Editorial el Drac. Aspinall, V. Manual completo de la enfermería veterinaria. UK: Editorial Paidotribo. http://www.paidotribo.com/pdfs/1105/1105.0.pdf