Introduction to Cardiac Disease in Companion Animals

Facts

• Cardiovascular disease affects 11% of dogs and up to 20% of cats

• Chronic valvular disease is most common in dogs (about 40% of cases), and can be mitral or tricuspid

• Multiple types of cardiac conditions exist in companion animals

Prevalence and Types of Cardiac Conditions

• Chronic mitral valvular disorder is the most common valve disorder and typically affects patients over the age of 10 years

  • 30% of valvular cases are tricuspid but these are generally less severe

• Valvular disorders are common in small breed dogs and rarely seen in cats

• Dilated cardiomyopathy (DCM) more common in large breed dogs, Doberman pinschers are particularly predisposed

• Cats experience different cardiac conditions like hypertrophic cardiomyopathy and DCM related to taurine deficiency

Disorders Where Nutritional Modification is Needed

• Congestive heart failure

  • Causes fluid retention

• Primary or secondary hypertension

  • Increased BP

• Obesity

• Cachexia

  • "Wasting" syndrome (wt loss, of musc. and fat)

  • Often driven by a chronic disease such as CHF

• Disorders related to dietary deficiencies

• Electrolyte imbalance disorders

Heart Failure

• Characterized by inadequate cardiac output and insufficient delivery of nutrients

• Results from a variety of structural and functional disorders of the heart of great vessels

• Patients often develop obesity and bronchitis because of heart failure, which worsens the condition

• Some clinical signs could include:

  • Weakness

  • Exercise intolerance

  • Dyspnea

  • Coughing

  • Ascites

  • Pleural effusion

Key Nutritional Considerations

Nutrients to think about:

• Sodium and chloride management critical

• Taurine supplementation important

• L-carnitine supports cardiac muscle function

• Phosphorus levels must be carefully controlled

• Potassium and magnesium balance crucial

Goals:

• Supply age appropriate nutrition

• Manage hypertension

• Decrease fluid retention

• Control signs associated with ascites

• Slow the progression of kidney disease

• Supply nutrients that may be lost when diuretics are prescribed

Sodium and Chloride Management

• Sodium, chloride, and water retention are commonly linked to CHF

  • Pets with heart disease lose ability to excrete excess sodium

    • Heart failure = less blood propulsion = decrease in BP and blood volume to organs = kidneys assume they are dehydrated and activate hormones such as aldosterone = more fluids cause more work for failing heart

  • More challenging to restrict in feline diets because of higher protein content

Taurine's Role in Cardiac Health

• Essential amino acid for cats but also important for dogs with myocardial failure

• Supports heart muscle function

• Important for dogs with specific breed predispositions (ie: Labs, Newfoundlands, Dalmations, etc.)

• Helps prevent dilated cardiomyopathy

• Can be supplemented in dogs with cardiovascular disease at a rate of at least 0.1% DM

L-Carnitine and Cardiac Function

• Deficiencies in dogs have been linked to DCM

  • Supports fatty acid transportation and helps detoxify mitochondrial processes

  • Critical for mitochondrial membrane enzyme function (energy)

  • SUMMARY: the heart can't generate enough energy to maintain contraction strength = dilation

• Beneficial even if deficiency is not directly causing cardiomyopathy

Phosphorus

• Important to evaluate other disease processes the patient may be experiencing such as kidney disease

• Patients with kidney disease are very sensitive to phosphorus and kidney disease is also commonly linked to heart disease

• Avoid excess phosphorus in cardiac patients

  • Due to its binding with calcium we risk deposition in tissues such as the heart (more rigid tissues = higher resistance and effort)

Electrolyte Balance

• Potassium and magnesium crucial for cardiac health

• Common problems: hyperkalemia, hypokalemia, hypomagnesemia

• Abnormalities can cause:

  • Cardiac dysrhythmias

  • Decreased myocardial contractility

  • Profound muscle weakness

  • Potentiate adverse effects from cardiac drugs

Protein and Cardiac Cachexia

• Cardiac cachexia is a major concern!

• Requires high-quality, digestible protein

  • Often not enough aminos being created to keep up with demand

  • Encourages adequate calorie intake = goal is to preserve lean muscle

• Addresses metabolic changes associated with heart disease

• *Not much research has been done in this area yet

Omega-3 Fatty Acids

• Positive effects:

• Electrically stabilizes heart cells by making them more resistant to dysrhythmias

• Reduced ventricular arrhythmia study in Boxers confirmed this

  • Anti-inflammatory effects

  • Cachexia prevention

  • Improved appetite

  • Antiarrhythmic effects

Omega-3 Fatty Acids

Negative effects:

• Can alter immune function

• Can reduce platelet aggregation → this may be beneficial in cats with cardiac disease

Water Considerations

• Provide clean, fresh water

• Be aware of local water mineral content

  • What minerals require monitoring!?

• Recommended: Distilled water or water with less than 150 ppm sodium

• Critical for patients with advanced heart disease

Emerging Research: Diet-Associated DCM

• FDA investigating potential diet-related heart disease

• Relationship to heart disease with grain-free and boutique diets (exotic ingredient diets)

• Diets with pulses and potatoes under scrutiny

• Over 1,390 dogs reported with diet-associated DCM

Misperceptions About Pet Nutrition

• Grains are not mere fillers → provide vitamins, minerals, essential fatty acids, and protein

• Grain-free does not mean carbohydrate-free → grains are replaced with ingredients like potatoes, beans, peas, or lentils

  • These can be more carbohydrate dense, deliver fewer nutrients, and are therefore less economical

• Food allergies to grains are extremely rare → <10% of all allergies are caused by grains

• Gluten intolerance is uncommon in pets → extremely rare in dogs and nonexistent in cats. Only one family of Irish Setters is known to have developed GI signs from consuming gluten

Nutrition Related Dilated Cardiomyopathy

• Characterized by heart enlargement which leads to impaired function

• Often abnormal heart rhythms, congestive heart failure, and even sudden death have been observed

• Some genetic related concerns for large and giant breed dogs

• Nutrition related DCM will be observed in atypical breeds like in small breed dogs

• DCM that is nutrition related will improve once the diet is changed

• Could also be a link between taurine deficiency and DCM. This should improve when taurine is supplemented

New Research:

• Concerns are now more with pulses in the diet (peas, lentils, chickpeas, and dry beans) vs. the absence of the grains

• Peas are of particular interest

• This was noted in dogs consuming grain inclusive diets with pulses that were still developing DCM