Cats diagnosed with heartworm disease that lack any clinical signs should not receive any form of adulticidal heartworm treatment, which kills adult worms, and can have fatal side effects in cats. Rather, the treatment of heartworm disease with adulticide medications should be reserved for those cats with persistent, serious clinical signs in which worm removal either is not an option, or it has failed to improve the signs of disease.
Some veterinary cardiologists have performed the surgical removal of adult worms from the infected cat's heart. This is not a common feline procedure, though, and it requires referral to an experienced surgeon with access to the proper equipment. Also, this surgery is usually attempted only in those animals in which an ultrasound has revealed a large number of worms.
Severely ill cats can be treated symptomatically to alleviate signs. Cage confinement, oxygen supplementation, anti-inflammatory drugs, and fluid therapy are commonly instituted. Once the cat is stable, heartworm treatment options can be considered.
