It may be hard to imagine that every dog, even the most rough-and-tumble of them all, has a sensitive ticker that’s at the source of that wagging tail and slobbery tongue. But just like humans, dogs aren’t invincible. A dog’s heart can grow ill as well, and even the bravest dog can be stopped in his tracks when struck with heart failure.

Heart disease affects 11 percent of all dogs, says YourDogsHealth.com. Among those, 15 percent struggling with heart disease are young dogs, and a striking 60 percent of dogs afflicted with heart disease are in their senior years, combating the disease daily. So whether or not your dog is young and vibrant or old and forgetful, it’s important to monitor her for symptoms of heart disease and then seek the proper treatment.

What is Heart Disease?

A vital muscular organ in your dog’s chest cavity, the heart consists of four chambers, two on either side of the heart, that pump blood through the body. As PetWellBeing.com explains, both sides of the heart also hold a set of valves. All parts of the heart work together to keep blood and oxygen reaching the biological systems in your dog’s body.

When heart disease is present, certain parts of the heart cease to function properly. The rest of the organ then tries to compensate for this improper function.

Heart disease leads to congestive heart failure (CHF) versus a heart attack, because symptoms appear and progress slowly, not suddenly as with a heart attack where the blood supply is abruptly cut off. Heart failure occurs when the heart can no longer pump enough blood to meet the dog’s bodily needs.

Heart disease comes in two forms: acquired and congenital. Acquired heart disease is a result of normal wear and tear on a dog’s heart over time. It can also be caused by an injury or infection. Dogs that have acquired heart disease usually are middle-aged or are senior dogs who’ve come into the age where heart disease starts to rear its ugly head.
According to YourDogsHeart.com, acquired heart disease accounts for 95 percent of all heart conditions in dogs. Congenital heart disease, on the other hand, affects only a small percentage of dogs with heart-related issues.

Congenital heart disease, unfortunately, is a result of genetics. Dogs with this type of heart disease are born with heart defects that later cause heart failure. This type of heart disease, says YourDogsHeart.com, is usually diagnosed as early as puppyhood.
Worrying about your dog’s heart health can be a very trying thing. But keeping an eye on your pooch and having him diagnosed as early as possible can help you extend his life.

What are the Symptoms of Heart Disease in Dogs?

Determining whether or not a dog is suffering with heart disease requires that a pet parent keep a close eye on the dog to watch for potential symptoms.

Because in the early stages of heart disease a dog’s body may adjust to the disease, pet parents may not see any significant signs of heart problems. But as the disease progresses there are symptoms that can point towards heart failure. Though there are various forms of heart disease with varying symptoms, there are certain ones common to all forms.

The following is a list of symptoms to look for in your dog:

  • Coughing
  • Changes in breathing (difficulty breathing; shortness of breath; labored breathing; rapid/fast breathing)
  • Changes in behavior (tiring easily; reluctance to exercise/not wanting to go for walks; less playful; slowing down/lack of energy; depressed/withdrawn)
  • Poor appetite
  • Weight loss
  • Fainting/collapsing
  • Weakness
  • Restlessness, especially at night
  • Swollen abdomen

Many of these symptoms can be easily mistaken with symptoms of other conditions. Still, make sure to keep a close eye on your dog and if something feels out of the ordinary, make sure to seek the advice of a veterinarian.

What Causes Heart Disease in Dogs?

As previously mentioned, heart disease comes in two forms: acquired and congenital. The causes associated with each are different.

Particularly with acquired heart disease, which makes up a small percentage of dogs with heart problems, the possible causes include infections, hormonal changes and nutritional deficiencies.

The following is a list outlining causes of acquired heart disease:

Bacterial Infections: Bacteria from the mouth (due to diseased teeth and gums) can enter the blood stream and attach to the heart valves, cause inflammation in the lining of the heart or in the valves, resulting in initial mechanical obstruction and possibly damage to the valves themselves. It is therefore important to regularly brush your dog’s teeth to prevent dental problems that may eventually lead to heart disease.

Heartworms: Heartworms can mechanically block the valves, and if a dog is heavily infested, the heartworms can clog an entire heart chamber.

Canine Parvovirus: Canine parvovirus often infects the heart muscles, and the resulting death of the heart muscle cells can sometimes cause acute heart failure in dogs.

Hormones: Hormones, especially of the thyroid, also affect heart function and performance. For example, a dog with hypothyroidism usually has a slower than normal heart rate.

Nutritional Deficiencies: A lack of Vitamin E or selenium is known to cause damage to the heart muscles.

The above causes can lead to dogs to develop either atrioventricular valvular insufficiency (AVVI) or dilated cardiomyopathy (DCM) in the heart.

“AVVI affects one or more of the heart valves,” says YourDogsHeart.com. “Heart valves normally form a perfect seal when closed; however, in AVVI one or more of these valves ‘leak,’ allowing blood to be pumped backwards.”

The backward flow caused by AVVI results in a sound that can be heard with a stethoscope, called a “murmur.”

Below is a list of breeds susceptible to AVVI:

  • Boston Terrier
  • Cavalier King Charles Spaniel
  • Chihuahua
  • Fox Terrier
  • Miniature Pinscher
  • Miniature and Toy Poodles
  • Miniature Schnauzer
  • Pekingese
  • Pomeranian
  • Whippet

DCM, on the other hand, is what occurs when the heart muscle fails, says Shaw Messonier, DVM, in Animal Wellness magazine. The heart’s contractions are weaker and so blood has more difficulty moving through the cardiovascular system. With repeated strain, the heart tends to stretch and enlarge, causing further problems with blood flow. Larger breeds of dogs tend to suffer from this heart condition.

DCM is the second most common form of heart disease in a dog. Below is a list of breeds susceptible to DCM:

  • Afghan Hound
  • American Cocker Spaniel
  • Boxer
  • Dalmatian
  • Doberman Pinscher
  • English Bulldog
  • English Cocker Spaniel
  • Great Dane
  • Irish Wolfhound
  • Newfoundland
  • Saint Bernard
  • Scottish Deerhound

The second cause of heart disease in dogs is congenital defect. As previously noted, a small percentage of dogs are born with heart defects that will develop into heart disease; these are congenital causes of heart disease.

Some of the most prevalent forms of congenital heart disease include: dilated cardiomyopathy (which was already explained), atrial septal defect (a hole in the dog’s heart), and mitral dysplasia (a leaky mitral valve).

How is Heart Disease Diagnosed in Dogs?

Though heart disease feels overwhelming and possibly a difficult condition to diagnose, it is actually fairly easy to diagnose.

Your veterinarian will listen to your dog’s heart with a stethoscope, and if he hears a heart murmur or irregular heartbeat, then the animal has heart disease.

At this point, many veterinarians might make the mistake of either waiting to see what happens, or automatically prescribing medication. But a murmur most times certainly means heart disease, so to “wait and watch” makes very little sense. In terms of prescribing medication, a murmur alone isn’t enough information to make a sound decision about what medication a pet parent should give to a dog. With further testing, the severity of the disease is more easily determined.

Once a heart murmur is detected, radiographs (X-rays), an EKG and echocardiogram of the heart will be necessary. These tests allow us to determine the stage of heart disease and will guide the treatment.

Chest X-rays in particular can help a veterinarian better analyze the heart’s shape and size for signs of heart disease, according to PetsWellBeing.com. X-rays can also give a veterinarian a glimpse into your dog’s lungs to see if there’s any build-up of fluid. It helps determine what type of heart disease and how severe it is.

Most asymptomatic dogs are at an early stage of heart disease and don’t require medication. With follow-up testing, close monitoring and care, a veterinarian can advise a pet parent when is the best time to put the dog on medication, which usually occurs when the disease has progressed or when heart failure occurs.

How is Heart Disease Treated?

There are several treatments available for dogs with heart disease. Though medications are available, such as diuretics and ACE inhibitors, Messonnier suggests that for asymptomatic dogs, natural remedies are a better approach.

The following are a few natural therapies that Messonnier recommends for dogs. Though most most recommendations are based on proven cardiac benefits for humans, Messonnier believes these remedies are just as helpful to dogs.

Coenzyme Q10: An antioxidant found in highest concentration in the heart, kidneys, liver and pancreas. It protects cell membranes and DNA from oxidative damage. Studies show that it can reduce systolic blood pressure and increase cardiac output in humans by improving heart contraction and dilating blood vessels to regulate bloodflow. Speak to your veterinarian about the proper dosage.

Hawthorn: An herb with flavonoids and oligomeric proanthocyanidins that greatly benefit dogs with heart disease. It has anti-arrhythmic properties, increases coronary bloodflow, decreases energy utilization by the damaged heart, and decreases cardiac excitability.

Omega-3 fatty acids: These are derived from cold water fish rich in EPA and DHA – such as salmon, mackerel, sardines and herring. Fish oil lowers mortality in human patients with cardiovascular disease. It may decrease blood clotting and can reduce atherosclerosis, coronary heart disease, arrhythmia, heart failure, sudden cardiac death and stroke.

Homeopathic remedies: Messonnier recommends using homotoxicology remedies, which are combination remedies that contain different homeopathics. In particular, he says that cactus compositum is a remedy good for dogs with circulatory disorders and heart weakness. Cralonin is another commonly used toxicology remedy for patients with heart disease.

Other supplements, such as Reishi, can also support heart health.

In more advanced cases of heart disease, a dog will be placed on heart medication.
Three different types of medication can be used for the animal with heart disease. With rare exceptions, these are only necessary with severe heart disease or failure. They have no place in the treatment of dogs with mild heart disease.

The usual medications recommended are as follows:

Diuretics: Work by removing excess water from a dog. This class of medication is only needed when fluid accumulation, most often in the lungs (pulmonary edema), is present. Because edema is not present until advanced heart failure occurs, diuretics should not be used for most dogs with heart disease.

ACE Inhibitors: Used to help the heart pump more efficiently and reduce resistance to blood flow by dilating blood vessels. ACE inhibitors may reduce coughing in animals with an enlargement of the left atrium. Animals taking ACE inhibitors should have frequent examinations and blood and urine testing because of potential side effects in the kidneys.

Pimobendan (Vetmedin): A new medication that opens the blood vessels, reducing the amount of work the heart has to do to circulate blood through the dog’s body. It also helps the heart pump more efficiently.

Unfortunately, there is no cure for heart disease/failure, but pet parents can empower themselves to use as many resources as possible to improve and extend their dogs’ lives with care and treatment.

How is Heart Disease in Dogs Prevented?

Heart disease doesn’t have a cure and unfortunately can’t be prevented, but there are ways to give your dog a fuller and longer life.

Along with the remedies already recommended, your dog’s veterinarian will most likely recommend a change in diet that supports heart health. Specifically, he or she may recommend restricting your dog’s sodium (salt) intake depending on the severity of your dog’s heart disease. This will most likely mean being aware of the treats you give your dog, whether they’re dog-specific treats or scraps from the table, writes YourDogsHeart.com.

As with most health issues, exercise is always important, but because a dog suffering from heart disease is more sensitive to overexertion, it’s important to consult with your veterinarian about the type, level, and frequency of exercise for your dog. Your dog could collapse or grow weak, so make sure to take the proper precautions.

Frequent visits to the veterinarian are extremely important and will help you monitor your dog’s health. It’s also important monitoring your dog’s appetite, behavior and level of movement at home as well. You might note changes in your dog’s weight or an increased thirst. These are important changes to talk to your veterinarian about.

Whether your dog has congenital or acquired heart disease, having the tools to get him diagnosed and treated will make all the difference in ensuring his longevity.

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This article has been written with the help of Dr. Carol Hamilton, who has 10 years experience as a veterinarian in Los Angeles, California, and kindly donated her time to answer my questions through e-mail.

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