The heart is one of the most vital organs in a dog’s body. It’s responsible for ensuring that blood, rich with oxygen and nutrients, is pumped to every cell. The organ plays a crucial role in regulating a dog’s bodily functions by circulating blood to deliver oxygen to muscles, organs, and tissues while removing waste products like carbon dioxide.

What is Heart Disease in Dogs?

Heart disease in dogs is a condition that can affect dogs of all kinds. Just like humans, a dog’s heart is essential for pumping blood and delivering oxygen throughout their body, so when the heart isn’t working properly, it leads to a lot of problems that affect their well-being. The tricky part is that heart disease often develops slowly, and the signs can be easy to miss at first.

Signs of Heart Disease in Dogs

Most heart diseases progress slowly, which makes them difficult to notice in the earliest stages. However, there are symptoms that can be linked to the condition. Here are some of the common signs of heart disease in dogs.

Persistent Coughing

Persistent and prolonged coughing can be an early sign of heart disease in dogs. This can happen for multiple reasons. One common reason is that the heart becomes enlarged, affecting other organs with its new size. Another could be that the heart loses its efficiency in pumping, which also disrupts the processes of other surrounding organs that rely on the heart.

Difficulty Breathing

Dogs with heart disease may experience shortness of breath and difficulty breathing even though they have not moved a lot. When your dog’s heart is having trouble, it may be unable to pump efficiently, leading to a buildup of fluids in the lungs. You’ll notice this when your dog starts to pant more frequently, even though it hasn’t done a lot of work.

Lethargy

Your dog may start to show signs of tiredness or lethargy as heart disease progresses. This is often due to reduced blood flow and oxygen supply to the muscles, causing your dog to tire quickly during walks, playtime, or even normal daily activities. If your dog is suddenly less interested in exercise or more reluctant to engage in physical activities, it could be a warning sign.

Weight Loss

Heart disease can affect a dog’s appetite. If your dog is eating less than usual or has become uninterested in food, it could be a sign of heart disease. Additionally, some dogs with heart conditions may begin to lose weight despite eating normally, as the body works harder to function, leading to muscle loss.

Swollen Abdomen

If your dog has a heart problem, it will be unable to pump efficiently. The abdomen becomes swollen, a condition referred to as ascites. This occurs when the heart struggles to pump blood effectively, causing fluid to build up into the abdominal cavity.

Blue or Pale Gums

A dog’s gums should be pinkish in a normal sense. However, if they start turning pale or blue, this usually means that they are not getting enough oxygen. This poor circulation of oxygen can be attributed to a heart problem, as the heart may have difficulty pumping efficiently.

Fainting

Fainting can occur when the heart is unable to pump enough blood to the brain. This can happen during periods of excitement, physical exertion, or even when your dog stands up too quickly. If you notice your dog collapsing or fainting, a vet visit should be a top priority.

Common Types of Heart Disease in Dogs

For heart diseases in dogs, there are two common types. These are congenital and acquired heart diseases. Each has its own set of characteristics and challenges.

Congenital Heart Diseases in Dogs

Congenital heart diseases are conditions that dogs are born with, often due to genetic factors. These conditions can affect the heart’s structure or function from a young age.

• Patent Ductus Arteriosus

PDA is a heart disease in dogs where the blood vessel ductus arteriosus does not close after birth. This vessel normally allows blood to bypass the lungs in a fetus. However, it should close after birth so the blood can circulate through the lungs. If it remains open, blood will flow abnormally between the heart and lungs, putting strain on the heart.

Signs of Patent Ductus Arteriosus

Dogs with PDA may exhibit signs like coughing, difficulty breathing, lethargy, and poor growth. In most cases, PDA will be diagnosed when a continuous heart murmur is observed during checkups at the clinic.

Treatment for Patent Ductus Arteriosus

PDA can cause irreversible damage to a dog’s heart, meaning that urgent treatment is essential. In most cases, our veterinary surgeons will manage the condition, as surgery is typically required.

• Pulmonic Stenosis

Pulmonic stenosis refers to a heart condition in dogs wherein their valves are narrowed, typically the ones between the right ventricle and pulmonary artery. Because of this narrowing, issues such as heart failure and death become a greater risk. Labrador Retrievers and Beagles are common victims of this disease.

Signs of Pulmonic Stenosis

Some common signs of pulmonic stenosis include difficulty breathing, fainting, exercise intolerance, and the buildup of fluid in the abdomen. In most cases, these symptoms can appear at any time during a dog’s life.

Treatment for Pulmonic Stenosis

Balloon valvuloplasty is usually the preferred treatment for pulmonic stenosis as it is minimally invasive. The goal of this treatment option is to widen the valve and create proper blood flow.

• Subaortic Stenosis

Subaortic stenosis in dogs when there is a constriction below the aortic valve. This makes it super hard for the heart to continue pumping blood. SAS is usually common in larger dog breeds.

Signs of Subaortic Stenosis

Dogs with heart disease can be observed to be weaker and more exhausted, having more difficulty breathing. The signs can range from mild symptoms, such as fainting, to dire ones, such as death.

Treatment for Subaortic Stenosis

The treatment procedure will depend on the situation of your dog’s SAS. Usually, no treatment is needed for mild cases. In the event that the SAS condition becomes more severe as your dog grows, medications in the form of beta-blockers are needed to help reduce the workload of the heart and control abnormal heart rhythms.

Acquired Heart Diseases in Dogs

Acquired heart diseases develop later in life, often due to age, infections, or other health problems. These conditions are more common in older dogs or certain breeds.

• Mitral Valve Disease

Mitral valve disease is a common type of heart disease in dogs, one of the most common forms of heart disease in dogs, especially in smaller breeds like Chihuahuas and Dachshunds. In this disease, the mitral valve doesn’t function as it’s supposed to, which causes some blood to leak in the wrong direction.

Signs of Mitral Valve Disease

The earliest signs of mitral valve disease don’t show up until in the later stages of a dog’s life. These symptoms are usually a persistent cough, rapid breathing, exercise intolerance, and a decreased appetite.

Treatment for Mitral Valve Disease

MVD is managed with medications such as diuretics. These medicines help remove the buildup of excess fluid and reduce the strain on the heart. Other medicines work to improve the function of the heart and protect the kidneys. As part of the treatment process, sufficient rest and lots of water should be given.

• Dilated Cardiomyopathy

DCM is a heart condition wherein the heart muscle of a dog becomes weaker. When this happens, the heart will be less effective in pumping blood. The blood will stay congested, leading to an increase in pressure and causing the walls of the heart to stretch. Breeds such as Newfoundlands and Boxers are at a higher risk.

Signs of Dilated Cardiomyopathy

Dogs with DCM may show signs of lethargy, decreased appetite, intolerance to exercise, and difficulty breathing. As the heart disease worsens, dogs might faint or collapse, especially during playtimes and exercise.

Treatment for Dilated Cardiomyopathy

DCM is usually managed rather than cured. To help manage this disease, ACE inhibitors work to make it easier for the heart to pump out blood. Diuretics are also a common medication used to help remove fluid from the lungs and make it easier for dogs to breathe.

• Heartworm Disease

Heartworm disease is another common heart condition in dogs caused by Dirofilaria immitis. These heartworms are super long and can live in a dog for several years. They are usually transmitted with the help of mosquitos that have taken in blood from infected animals. The infected blood can contain young heartworms, which can develop in the mosquito. When the mosquito bites a dog, these heartworms are transmitted into the dog and develop further. 

Signs of Heartworm Disease

Some of the earliest signs of heartworm disease include lethargy, coughing, and exercise intolerance. However, if the infection worsens, collapse and sudden death due to heart failure can be possible.

Treatment for Heartworm Disease

Heartworm disease can be cured with injectable drugs that kill the heartworms. To help keep your dog free from these parasites, heartworm preventives will be administered. These medications prevents younger heartworms from developing. Supplementary medications such as steroids help reduce the inflammation present.

Conclusion

Heart disease in dogs can be super concerning, which is why it’s important to understand the signs so we can provide immediate vet care. While some of the signs consist of common symptoms of various diseases, such as lethargy, weight loss, and coughing, it’s important to take note of these for your next visit with our vets.