In dogs and cats, the most common types of heart disease include cardiomyopathy and valvular heart disease. Congestive heart failure occurs late in the course of any type of heart disease as the heart muscle fails to adequately pump blood throughout the body.
Valvular heart disease is the most common heart disease in dogs, occurring most commonly in older small breed dogs (the prevalence is estimated at 75 percent of dogs over 16 years of age). This condition occurs as the heart valves (most commonly the mitral valves that separate the left atrium from the left ventricle) degenerate as a result of acquired chronic structural changes in the valves. Small nodules of myxomatous degeneration occur in the valves, causing them to thicken, become irregular, and retract from each other. This retraction allows blood to flow in a “backward” direction as well as a forward direction. This abnormal blood flow cause “regurgitation” of blood, which is heard through the stethoscope as a result of turbulence caused by the regurgitation. With time, coughing and exercise intolerance may occur as regurgitation worsens and the heart can no longer adapt, leading to early congestive heart failure.
Dogs may also be afflicted with cardiomyopathy, where the heart muscle itself is actually diseased. Larger breeds of dogs (especially Boxers and Doberman Pinschers) may be afflicted with dilated cardiomyopathy, although increasing incidence is reported in Cocker Spaniels. The average age of affected dogs is four to eight years. The cause is unknown, although the higher incidence in purebred dogs when compared to mixed breed dogs suggests a genetic cause. Additionally, L-carnitine or taurine deficiency has been shown in some dogs.
In dilated cardiomyopathy, the heart enlarges as the heart muscle progressively becomes thinner. The thinner muscle does not pump blood adequately, and with time congestive heart failure occurs.
Cats with heart disease are most commonly affected with hypertrophic cardiomyopathy. In the past, dilated cardiomyopathy was also common. Recent evidence that taurine deficiency contributed to most cases of feline dilated cardiomyopathy has resulted in manufacturers increasing the amounts of taurine in commercial cat foods. As a result, dilated cardiomyopathy is rare in cats today; unless owners prepare food at home and do not adequately supplement with taurine. This is especially problematic if owners insist on feeding cats vegetarian diets, as vegetables do not contain taurine.
Hypertrophic cardiomyopathy appears to be genetic in origin in cats. Hypertrophic cardiomyopathy most commonly occurs in younger (four to eight-year-old) male cats. In this condition, the heart muscle thickens, often to the point where the chambers of the heart diminish in size to the point where little blood is able to be pumped around the body. This lack of forward movement of blood results in heart failure in severe, chronic cases of hypertrophic cardiomyopathy. In some cases of cardiomyopathy in cats, emboli (a collection of clotted platelets) forms in the heart and travels to another area of the body, most commonly the lower aorta. This embolus then causes lack of blood to the body part served by the blocked aorta, usually one or both hind limbs, causing paralysis. Often this secondary effect of cardiomyopathy prompts the client to bring in the cat for a veterinary visit, allowing the diagnosis of the underlying heart disease.
Natural Diet for Treatment of Heart Disease in Pets
Dietary therapy is designed to regulate sodium levels. In heart failure, sodium is retained rather than being excreted by the kidneys. Sodium retains fluid in the body, which causes fluid to leak from the blood vessels into the lungs, liver, and other organs causing the signs (coughing, abdominal fluid, and such) seen in pets with congestive heart failure.
To reduce sodium retention, salt is reduced in diets designed for pets with heart disease. Since commercial pet foods have excessive amounts of sodium to increase palatability and act as a preservative, these diets are not recommended for pets with heart disease. There are several medicated diets prepared for pets with heart disease. However, they may contain by-products and chemical preservatives that are not always consistent with a holistic nutritional program, although they may have a place in the management of heart disease if the owner cannot prepare a homemade diet or if the pet will not eat the homemade diet. Homemade diets can fit the need for holistic, low-sodium diets.
Pets with heart failure may have low potassium levels resulting from decreased food intake (common in pets with heart failure) and the use of diuretics such as furosemide (Lazix). Even with normal blood levels, cellular levels of potassium may be decreased. Extra potassium can be supplied using supplements or potassium chloride (salt substitute). Discuss this with your veterinarian before beginning potassium supplementation.
Magnesium may also be decreased in pets with heart failure, once again due to reduced food intake and use of diuretics. Magnesium depletion is difficult to prove based on blood levels as, similar to potassium, blood levels do not coincide with cellular levels. Magnesium supplementation under veterinary supervision may be warranted.
Supplementation with Coenzyme Q10, taurine, and carnitine may be helpful in pets with heart disease and heart failure. Taurine deficiency can cause dilated cardiomyopathy in cats. This disease is quite rare today, as pet food manufacturers have increased the levels of taurine in commercial pet foods. Cats are true carnivores. Unlike dogs, they cannot make enough taurine to meet their daily needs and must receive taurine from their diets. Homemade diets for cats containing animal proteins such as meat or fish contain adequate taurine levels. However, processing results in loss of taurine if the meat juices are removed. Pouring the juices over the diet, or feeding raw meats if the owner is comfortable with this, can replace this taurine. Eggs and cottage cheese contain little or no taurine and must be supplemented with taurine. Vegetarian diets (including tofu-based diets) do not supply taurine, as plants do not make taurine; these diets must also be supplemented with taurine to meet the cat’s needs.
Shawn Messonnier, DVM
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Shawn Messonnier DVM Past Supporting Member, Oncology Association of Naturopathic Physicians Author, the award-winning The Natural Health Bible for Dogs & Cats, The Natural Vet’s Guide to Preventing and Treating Cancer in Dogs, and Breast Choices for the Best Chances: Your Breasts, Your Life, and How YOU Can Win The Battle!
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