Written by Dr Sarah-Jane Molier BVM&S MRCVS BSc (United Kingdom)
Heart disease is common in dogs, with around 10% of dogs who attend a vet practice suffering from some form of heart disease. Sadly, heart disease is also one of the top ten causes of death in cats. As with humans, there are risk factors for heart disease in pets. While many of these are unavoidable, there are some measures you can take to support their health. This article explores heart disease in dogs and cats, and the important role nutrition can play in supporting heart health.
What heart conditions can dogs and cats suffer from?
Mitral valve disease (also known as MVD, myxomatous mitral valve disease or myxomatous valve degeneration) is the most common form of heart disease in dogs. The mitral valve is a valve that separates the two chambers on the left side of the heart. It’s job is to ensure that blood only travels in one direction through the heart. The left side of the heart receives oxygen rich blood from the lungs and pumps it back around the body. In MVD, the valve leaks, allowing blood to leak back through the valve, in the wrong direction (known as mitral regurgitation). MVD is more common in older, small breed dogs.
Dilated cardiomyopathy (DCM) is another common heart disease in dogs, especially large and giant breeds. It leads to progressive enlargement of one of the left chambers of the heart, causing the heart difficulty pumping blood around the body. DCM can happen as a primary condition, or it can occur secondary to other causes, such as diet or infection.
Cats most commonly suffer from hypertrophic cardiomyopathy (HCM). HCM is more common in certain breeds, such as the Maine Coon, Sphynx and Persians. In HCM, the walls of the heart become very thick, reducing the space inside the chambers of the heart. This makes it very hard for the heart to effectively pump blood.
What are the signs of heart disease in dogs and cats?
The symptoms of heart disease are similar for both dogs and cats. Often, the first sign of heart disease is a heart murmur or abnormal rhythm detected by your vet at a routine check-up, before you have noticed any symptoms.
Signs of heart disease in dogs include:
- Coughing
- Fast breathing or increased panting
- Lethargy (low energy)
- Reluctance to exercise
- Collapse
- Poor appetite
- Weight loss
- Abdominal distension (swollen tummy)
Signs of heart disease in cats include:
- Fast breathing
- Shallow breathing
- Noisy breathing
- Open mouth breathing (like a dog panting)
- Lethargy
- Collapse
- Poor appetite
- Weight loss
- Abdominal distension
If you notice any of these signs in your dog or cat, you should contact your vet straight away.
Treatment for heart disease
Unfortunately, heart disease is progressive. While dogs and cats may need no treatment at all when an issue is first detected, the disease will progress and treatment will be tailored to your pet’s stage of disease and symptoms.
Treatment can involve:
- Medication to remove retained fluid from the body
- Medication to improve the strength of the heart’s contractions (heartbeat)
- Drugs to control the rate or rhythm of the heartbeat
- Drugs to control blood pressure
- Medicine to help prevent blood clots
- Sometimes (rarely) surgery
Your veterinarian will monitor your pet regularly, and may advise changes to the medications and / or doses, depending on how the disease is progressing.
How to prevent heart disease
As with many diseases, heart conditions cannot be prevented in most cases. There is often an underlying genetic predisposition and / or an age related change. However, there are a few things you can do to help keep your pet’s heart healthy:
- Weight management
Keeping your pet at a healthy weight has many health benefits, so it’s not only important for a healthy heart! Obesity is a serious welfare issue in pets. Being overweight can reduce life expectancy and increase the risk of various medical conditions, such as arthritis, heart disease, diabetes and some forms of cancer.
- Regular check ups
Many heart conditions are ‘silent’ until the later stages of the disease, meaning your pet won’t show any clinical signs initially. This highlights the importance of regular vet checks, giving them the opportunity to detect a heart murmur or abnormal rhythm before your pet is showing any signs, allowing earlier intervention.
- Dental hygiene
A lesser known fact: keeping your pet’s mouth healthy can also help to protect their heart! In severe dental or gum disease, bacteria from the mouth can enter the bloodstream and damage the heart.
- Nutrition
We all know that good quality, balanced nutrition is important for overall health. Hence the saying “you are what you eat”. Well, this is just as true for pets as it is in humans.
In 2018 the FDA (US Food and Drug Administration) started
investigating reports of cases of DCM in dogs eating certain pet foods, which contained a high proportion of non-soy legumes and pulses. The exact link or cause has
not yet been determined, but the number of diet-related cases of DCM has decreased since then.
Cats and dogs with heart disease also have specific nutritional requirements.
Nutrition for dogs and cats with heart disease
Some of the key nutritional factors for supporting heart health include:
- Palatability, protein content and calories
Heart disease can cause weight loss, especially loss of muscle mass. In advanced heart disease, this loss of weight and muscle is known as ‘cardiac cachexia’ (which is medically defined in dogs as unintentional weight loss of more than 7.5% of a patient’s usual body weight). Once cardiac cachexia sets in, it has a negative effect on prognosis (i.e. it is associated with a poorer outcome for the pet). Importantly, cardiac cachexia is easier to prevent than it is to reverse.
The
ACVIM (American College of Veterinary Internal Medicine) therefore recommends feeding a highly palatable (very tasty!) diet, which contains enough protein and calories to maintain an optimal body condition, from early on in heart disease.
This means low protein diets are not recommended in heart disease, unless your pet is also suffering from advanced kidney disease, since it is important to maintain muscle mass.
- Sodium
Once congestive heart failure sets in, it leads to retention of sodium, chloride and water in the body. This means we have to be careful about the salt content of diets for dogs with heart disease.
Early on in heart disease, the ACVIM consensus is to ‘modestly’ restrict sodium intake for dogs. This needs to take into account all treats too, and would include avoiding human food, which is often high in salt!
Later on, when the dog is starting to show signs of heart failure, the recommendation is to restrict the sodium further (to below 0.30 % on a dry matter basis).
For cats, the ACVIM advice is to prioritise calorie intake over salt restriction, since very low sodium diets can be less palatable.
- Amino acids
A deficiency in the amino acid taurine can cause DCM, especially in cats. Cats cannot synthesise their own taurine, so they rely on their diet to provide this essential nutrient. Luckily, good quality, nutritionally complete, cat foods will contain enough taurine. Be wary of home-made diets (not formulated by a veterinary nutritionist) or vegetarian cat foods. While dogs can make their own taurine, some breeds are more prone to deficiency.
- Omega-3 fatty acids
Omega-3 fatty acids (found in fish oil) have anti-inflammatory properties and can help to maintain muscle mass, so diets containing omega-3 fatty acids may be beneficial.
There are some other nutrients that are important in heart disease, such as potassium and magnesium. Heart disease can alter the levels of these nutrients, as can certain medicines used to treat heart disease. If your veterinarian is worried about an excess or deficiency of these nutrients, they may suggest a blood test to measure the levels in your pet’s blood.
Conclusion
Dogs with heart disease need a highly palatable diet, which contains enough calories and good quality protein. Depending on the stage of disease, they also need some degree of salt restriction.
Your veterinarian will be able to advise you on the best diet for your pet’s unique needs, and stage of heart disease.
There are ‘prescription diets’ for pets with heart disease, which are carefully formulated to contain an optimum nutrient profile for heart health. However, every pet is different! Since many cats and dogs with heart disease are elderly, they may also have concurrent ‘old age’ illnesses, such as chronic kidney disease.
Speak with your veterinarian about the best diet for your pet.
