While we don't have alot of heartworm cats at work (seems it's more rare in cats) I do know a few things about them.

The tests aren't accurate and are difficult to rely on, and a negative test result does not rule out heartworms. Testing is not as reliable as in dogs.

In cats it's more of a lung disease although it does affect the heart also.

The best diagnosis tools for heartworms in cats is an xray, and ultrasounds with an experienced vet to interpret them, and blood work particularly a CBC (blood cell count).

To my knowledge there is no treatment for cats with heartworm. Sometimes their bodies can reject the worms on their own (cats tend to have far fewer worms than dogs) however there will always be lasting damage to the lungs and other respiratory system from the infection.

Here is more detailed information about Heartworm disease in cats for further reading.

http://www.heartwormsociety.org/article.asp?id=1142

http://www.knowheartworms.org/mythone.asp


You might want to take a print out from that first site to your vet and just discuss the possibilities. I hope your kitty recovers from his problem and starts feeling better soon.


FYI for cat owners.

Preventative is usually the best and only thing a cat owner can do given the limited options available to cats at this point and time. Since reliable testing and treatement are not available for cats preventing the infection is really the best way to fight it.

We frequently use Revolution at work for cats for the heartworm preventative, as well as many other things it can take care of (fleas, earmites, roundworms).