Heart Disease in a Dog

Congenital Types

• Dilated cardiomyopathy is simply an enlargement or dilation of the heart chambers. It is the most common reason for congestive heart failure in dogs. It is thought to be genetic in some breeds. Mitral valve disease is a defect in the mitral valve of the heart. Blood flow backs up into the left chamber of the heart, causing it to flow ineffectively to other areas of the body. According to Cavalier Health.org, mitral valve disease is the most common heart disease in older dogs, affecting more than one-third of dogs over ten years of age.

Preventable Type

• Heartworm infestation is a preventable disease of the heart caused by the bite of an infected mosquito. The mosquito deposits a parasite into the dog's bloodstream which eventually makes its way to the dog's heart. According to Web MD, it takes approximately seven months for the larvae to become heart worms. When mature, the heartworms begin to multiply. Dogs can be infected with as many as 250 adult heartworms. In time, the worms make their way to other organs. Heartworm disease occurs in most areas of the U.S. and is particularly prevalent in warm, damp climates.

Breeds Affected

• Some breeds seem to have a predisposition for certain heart diseases. Dilated cardiomyopathy is thought to be genetic in Newfoundlands, boxers, Irish wolfhounds, Doberman pinschers and Portuguese water dogs. The disease usually strikes male dogs under 7 years of age. Mitral valve disease tends to show up early in the life of Cavalier King Charles spaniels, toy and miniature poodles, bull terriers and Cairn terriers. Mitral valve disease seems most likely to occur in small breeds, but it also affects the German shepherd and great Dane. Males are affected more frequently than females by mitral valve disease.

Symptoms

• Heart diseases in dogs share many similar symptoms, such as lethargy, lack of appetite, weight loss, shortness of breath, abdominal distension and coughing. The affected dog often exhibits a marked lack of enthusiasm for play and food. He tires easily and appears depressed. Heart murmurs are often detectable upon veterinary examination. Heartworm disease will eventually cause additional symptoms depending upon which other organs are affected. Heart failure is a common outcome.

Treatment and Prevention

• Treatment for congenital heart disease in dogs usually involves the use of diuretics to reduce the fluid build-up around the heart and lungs. Sodium and fat restricted diets may be recommended by your vet. Medications are often prescribed to help support the heart and improve function and circulation. Depending on your dog's condition and severity of disease, your vet may decide to either increase or reduce his activity. According to America's Animal Society, dogs affected by mitral valve disease or their parents should not be bred. However, symptoms associated with mitral valve disease often do not show up until after the dog is of breeding age. Upon diagnosis of heartworm disease, your veterinarian will administer a series of injections meant to eliminate the worms from your dog's bloodstream. The medication is not always successful, depending on the severity of the disease. Heartworms are preventable by placing your dog on a heart worm prevention program. It is given in the form of a monthly pill or a yearly injection.