Diagnosing and Treating Heart Disease in Dogs and Cats

Many breeds of dogs and cats are prone to heart disease. While there are no proven methods to decrease the risk of heart disease in a breed genetically prone to its development, a pet owner has many nutritional, herbal, and therapeutic options to support healthy heart function. 

What types of heart disease are prevalent in cats?
Heart disease is a silent killer with cats causing 62% of sudden death cases in cats. Radiographs rarely show heart enlargement, even when significant heart disease is present. Cats often do not have murmurs even with advanced heart disease. The types of heart disease, diagnosis and treatment for cats are detailed in the following blog: https://drjudymorgan.com/blogs/blog/heart-disease-in-cats?_pos=1&_sid=1446aca23&_ss=r

What types of heart disease are prevalent in dogs?

Mitral Valve Disease: This is the cause of 75% of heart disease in dogs. Small breed dogs are more prone to mitral valve disease (MVD). Breeds affected include Cavalier King Charles Spaniels, English Toy Spaniels, Dachshunds, Pekingese, Pugs, Chihuahuas, Maltese, Yorkies, Papillons, Bichons, and small poodles and terriers. Most breeds susceptible to MVD have an adult body weight of less than 9 kg (20 pounds).  MVD, a degenerative valve disease, is an inflammatory condition, as evidenced by studies showing increased circulating inflammatory markers in dogs suffering with this disease. The risk of MVD increases with age. A heart murmur is a leak, or “turbulence” in the blood flow. Murmurs are graded according to severity from low (1) to high (6). The grade has nothing to do with the strength of the heart - the heart muscle may be working normally. But over time with MVD, the heart will enlarge and the condition will eventually lead to heart failure. Symptoms of MVD include:

  • Rapid shallow breathing at rest 
  • Depressed attitude
  • Restlessness (due to fluid build-up in the chest)
  • Syncope (fainting)
  • Coughing/gagging sounds

Dilated Cardiomyopathy (DCM): DCM is mostly a large-breed disease. Breeds affected include Dobermans, Boxers, Great Danes, Greyhounds, Irish Wolfhounds, Afghan Hounds, and Saint Bernard’s. Boxers may have a carnitine responsive cardiomyopathy while Cocker Spaniels and Golden Retrievers may have taurine-responsive disease. DCM is a primary disease of the heart muscle. Over time, the muscle becomes thin, stretched, and weak, losing its ability to pump blood through the system. Symptoms of DCM include:

  • Sudden death
  • Respiratory distress
  • Syncope (fainting) 
  • Weakness
  • Ataxia (wobbly gait)

Risk factors associated with worsening heart disease:

  • Breed predisposition
  • Age
  • High blood pressure
  • Dental disease
  • Bacterial, rickettsial, and viral infections
  • Heartworms

 How is heart disease diagnosed in dogs?

Any pet suffering from degenerative heart disease of any type should be under the care of a veterinary cardiologist. An ultrasound, called an echocardiogram, is the best method to determine stage of heart disease and heart function. Medications are available that will increase longevity and help keep pets comfortable. A diagnosis of heart disease is not an immediate death sentence. Many pets will live for years after diagnosis when given a high quality diet and supplements. If you have a breed that is predisposed for heart disease, it is best to place your dog under the care of a cardiologist.

Clinical signs vary among different breeds in dogs. This may result in a delay in proper diagnosis or a misdiagnosis. Veterinarians need to know the different signs and symptoms between the breeds. Research your breed, and be sure your veterinarian is familiar with your breed.

When diagnosing heart disease, your veterinarian should listen for a murmur, which is detected by a stethoscope. Heart enlargement can be seen on a chest x-ray. Blood pressure should be measured.  A human blood pressure wrist cuff can be used on larger dogs. Work with your veterinarian to determine the best placement of the cuff on your dog’s leg.

Tests to be performed include urinalysis, CBC (complete blood count), and a complete chemistry panel. These tests will detect other organ damage caused by heart disease. Special blood tests, such as the NT-proNP test evaluates the pressure of the heart based on the stretching of the heart muscle. This test involves a very special blood draw and procedure. A  cTnl blood test checks for elevated serum concentration of cardiac troponin and is a highly sensitive and specific marker of heart damage.

Heart Disease is graded in stages:

  • Stage A - No symptoms, but breed prone to MVD
  • Stage B1 - Murmur, no need for meds, no symptoms
  • Stage B2 - Murmur, weakness in heart muscle, a few symptoms. The decision to start medication will depend on the individual patient. It is up to the cardiologist to suggest a treatment plan.
  • Stage C - Clinical signs with heart enlargement. Medication will be prescribed. Medication can place the disease in a “holding pattern”, often for long periods of time.
  • Stage D - heart enlargement with heart failure that is refractory to traditional medications. Medications may be changed out, such as a more powerful diuretic (torsemide). Cardiologist will often give a prognosis of 2-3 months of remaining life, although many pets will outlive that prognosis by months to years. Animals in Stage D failure may benefit from supplemental oxygen which can be delivered at home with an oxygen concentrator and home ICU cage. Be sure to place a cooling mat inside the cage when in use.

Complications that can be associated with heart disease:

  • Tumors in the heart
  • Hypertension (high blood pressure)
  • Pulmonary hypertension (high pressure in the lungs)
  • PLE - protein losing enteropathy
  • Ascites - fluid leaking into the abdomen
  • Arrhythmias (abnormal heart rhythms)
  • Syncopy (fainting)

How can you proactively treat heart disease?

Support younger dogs and cats that are prone to heart disease, even though a murmur may not yet be detected. No good studies have been performed to prove this, however I recommend proactive care early in life which may delay the onset of heart disease. Typical supplements I recommend for my dogs and cat patients include:

  • CoQ10 - Studies have shown CoQ10 causes a reduction of cardiac troponin levels in dogs with heart disease. Systolic function increased significantly because CoQ10 is a factor required during energy production in muscle cells. Thus, CoQ10 supplementation may improve energy availability for cardiac muscle contraction. CoQ10 may protect heart muscle cells from injury through its antioxidant action. Thirdly, CoQ10 was found to decrease vascular resistance, therefore allowing blood flow from the heart to move forward more easily. Recommended doses of 1 mg per pound of body weight are not high enough to produce these beneficial effects. I dose my dogs and patients much higher, at around 5 mg per pound twice daily.
  • Five Leaf Botanicals - Canine Heart Health Program has strongest heart herbs and therapies that you can use to nourish your dog’s heart health.
  • L-carnitine - 500 mg for small dogs up to 2,000 mg for large dogs twice daily. Nutritional sources with high levels of carnitine include red meat (beef) and heart muscle meat of any source.
  • Taurine (found in Rx Vitamins Feline Essentials and Rx Vitamins Formula HL) - 250 to 750 mg twice daily (some dogs with DCM may require up to 5,000 mg daily). Nutritional sources with high levels of taurine include shellfish such as mussels, scallops, and clams, dark meat poultry, and goat milk.
  • Hawthorn - increases cardiac muscle contraction strength, found in many herbal formulations of differing strengths. Combination formulas often contain this herb, however these formulas often do not have high enough doses of all ingredients I want to include; I use single ingredient products and layer them in. This may be more of an inconvenience but it allows me to tailor the protocol based on my pet’s condition. 
  • Omega 3 fatty acids decrease cardiac inflammation, decrease triglycerides, and decrease muscle wasting. If the pet cannot tolerate fish oil, use phytoplankton such as algae oil or phytoplankton. Fish oils should not be stored in a plastic bottle or exposed to air, as this can result in oxidation and rancidity. Give 30 mg of EPA and DHA per pound of body weight daily, along with 1 to 2 IU of vitamin E per pound of body weight.
  • Calcium - the diet needs to have adequate calcium, particularly when formulating home prepared diets.
  • Pets with heart disease often have low vitamin D levels. Vitamin D levels should be tested before beginning vitamin D supplementation. Toxicity from high levels of vitamin D can be a problem
  • Vitamin E, important for heart muscle function, acts as an antioxidant to protect heart cells from oxidative damage.
  • Selenium - trace mineral that supports cardiac function - found in fish, chicken, beef, and pork.
  • Chromium - trace mineral that supports cardiac function - found in broccoli and mushrooms.
  • D-Ribose - D-Ribose is a natural sugar. It has been shown in several human studies to increase cardiac contractility and prolong survival from heart failure in people. It is very inexpensive, and no side effects have been reported.
  • PEA - natural anti-inflammatory that works on the endocannabinoid system.
  • CBD oil - anti-inflammatory and anti-anxiety effects; generally recommended dose is 1 mg per 10 pounds body weight 2 to 3 times daily.

Nutritional additions for my pets and patients include:

  • Fermented raw goat milk - high in taurine, medium chain triglycerides, and vitamins essential for cardiac function; Yin tonic to decrease inflammation. Goat milk also contains GABA (ƴ-aminobutyric acid), a neurotransmitter, with diverse physiologic effects, such as modulation of blood pressure, immune function, insulin sensitivity and stress.
  • Species-appropriate meat-based diet, preferably raw or gently cooked, that includes heart muscle meat. From a Traditional Chinese Medicine perspective, heart failure and heart enlargement are related to Heart Qi Deficiency and Blood Stagnation. When designing a diet to support optimum heart function, I include Qi tonics and ingredients to resolve stagnation that keep the blood moving. 
  • Qi (energy) tonic foods - beef, dark meat poultry, rabbit, tripe, pumpkin, squash, sweet potato, Golden Paste, and Shiitake mushrooms. An herbal formulation for Heart Qi deficiency is Stasis in the Mansion of the Blood.
  • Foods to resolve stagnation and help eliminate fluid build-up - celery, watermelon, dandelion greens and roots, barley, mushrooms, garlic, and parsley.
  • Blood tonic foods - egg yolks, sardines, dark leafy greens, liver, beef. Heart Blood deficiency can be treated with the herbal formulation Si Wu Tang (Four Substances) for anemia or Heart Blood deficiency with Shen disturbance (behavior changes, vocalizing at night, fear of loud noises) with the herbal formulation Tian Wang Bu Xin Wan (Emperor's Teapills).
  • Recipes for heart support diets can be found here:



I am NOT a fan of the prescription heart diet foods. Most are made with inferior ingredients that have been highly processed, with synthetic chemical additives. Omega 3’s are added but become rancid in the heating process of making kibble. Additional synthetic vitamins and minerals that support heart health are being added; however, some animals see the synthetic vitamins as “foreign” to the system resulting in gastrointestinal problems and allergies.

Dogs and cats have no need for carbohydrates in the form of grains. Our pets have zero requirements for grains in food. Feed a meat-based diet. Dry kibble does not supply the amount of meat needed to support the heart.

The best way to support your pet’s heart is to feed real, whole foods, free of synthetic ingredients. Supplements should also be derived from real food rather than synthetic ingredients. My patients have performed much better when fed real foods that contain the necessary ingredients for optimum heart health.

Treats to support heart health include freeze-dried hearts, freeze-dried lung, and fish-based treats high in omega 3 fatty acids. You can also make your own dehydrated treats at home.

For more information on heart disease, see my books From Needles to Natural, Learning Holistic Pet Healing,  and Yin & Yang Nutrition for Dogs, Maximizing Health Using Whole Foods, Not Drugs.

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