Cardiovascular System
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NJ Veterinary Medical Association
390 Amwell Road, Suite 402
Hillsborough, NJ 08844
Phone:  908-281-0918
Fax:  908-450-1286

Health Concerns: Cardiovascular System

Dear Veterinarian:
My cat has been coughing and gagging and occasionally vomits. My veterinarian would like to do x-rays and blood work including a heartworm blood test. I though only dogs get heartworm. Can cat get it too?

Dear Pet Owner:
Yes! Heartworm disease is caused by an infection with a parasite called Dirofilaria immitis, a blood parasite transmitted by mosquitoes. The parasite, which may be 12-14 inches long, matures in the heart, replicates, and produces microfilaria ( immature heartworms) which are released into the bloodstream. A mosquito feeds from the infected pet and brings the microfilaria to the next victim it bites to start the cycle again.

Although the dog is the traditional host for heartworm disease, sometimes the cat can be innocently infected. Cats are generally more resistant to infection but are at risk if they live in a geographic area where dogs are known to harbor infection. Indoor cats are also at risk as mosquitoes can enter the home and feed.

However, in the cat, the heartworm cycle may be interrupted. Since the cat is not the traditional host, the parasite may reach the heart and its vessels or it may get "lost" and travel to other parts of the body such as the lungs or nervous system. This is called "aberrant migration." The cat may also have only one or two mature worms in its system compared to the dog that may have many. This aberrant migration and low worm burden account for the symptoms we see in cats as well as the difficulty in detecting and diagnosing the disease. Also, heartworms do not live as long in cats (2-3 years) compared to dogs (5 years).

Some cats with heartworm disease cough or have problems breathing or have signs suggestive of asthma. Lack of appetite, vomiting and weight loss may also occur. Others may have neurologic symptoms such as a wobbly gait, collapse, or seizures. Unfortunately, some cats may have sudden death resulting from a thromboembolism (a clot in a blood vessel).

Testing for heartworm disease is trickier in cats than in dogs, but feline heartworm antibody and antigen tests may be performed. The antibody test detects if your cat has ever been exposed to heartworm while the antigen test confirms infection. X-Rays of the heart and lungs as well as an ultrasound of the heart and vessels may also need to be performed to assess any changes consistent with the disease. Your veterinarian will take all of the results of these tests into account before a diagnosis of feline heartworm disease is made.

Treatment for heartworm disease depends on how critical the infection is affecting the cat. Mild symptoms may be controlled with prednisolone, a cortisone oral medication, with follow-up on diagnostic tests. In cats with extreme respiratory compromise, emergency therapy including hospitalization, oxygen, and intravenous steroids may be needed. The medication customarily used in dogs to rid heartworms is not normally used in cats because they are too sensitive to the drug. That is why prevention in cats at risk is important.

Currently, there are three available medications for cats. If your cat is already infected, it is still recommended to be on a preventative product to prevent new infections from further compromising your cat.

Although heartworm disease is not as common in cats as it is in dogs, it can lead to serious consequences. It is important to discuss your cat's potential risk with your veterinarian so that you can make an educated decision on what is best for your pet.


Dear Veterinarian:
Whenever I go to the doctor, the nurse checks my blood pressure. For years, I have taken my dog and cat to the veterinarian and their blood pressure has never been checked. They are both 9 years old. Now, my veterinarian wants to do blood tests on them and also check their blood pressure. Why hasn't his been done all along?

Dear Pet Owner:
Dogs and cats usually don't suffer from high or low blood pressure when they are young and healthy. As they get older, body systems that affect the blood pressure can change. Just as in people, high blood pressure is a silent danger.

Older cats are prone to a problem called hyperthyroidism, where their thyroid gland makes too much hormone. This increases their metabolism, and one of the effects can be elevated blood pressure. Dogs and cats whose kidneys are degenerating or diseased can also have high blood pressure. That's because the kidneys secrete a hormone that regulates blood pressure, and an abnormal kidney can lose its ability to regulate this properly.

Some animals with heart disease need their blood pressure regulated to ease the work the heart has to do in efficiently pumping blood. And sometimes, the aging process or other hormone imbalances will cause elevated pressure.

High blood pressure can cause severe problems. It can result in heart failure, fainting, seizures, and chronic nosebleeds. It can lead to blindness, because fluid can accumulate in the back of the eye and the retina can detach. There can also be bleeding into the eye itself.

If your veterinarian diagnoses high blood pressure, she will also try to find out what is causing it. If a primary problem can be identified, that will be treated. Also, your pet will be placed on medicine to regulate his blood pressure, and he will have to be monitored regularly.

Take your veterinarian's advice about this. It's one of the ways you can ensure your pets have a long and healthy lives.

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