Heartworm is a serious and potentially fatal disease in cats. It is caused by foot-long worms (heartworms) that live in the heart, lungs and associated blood vessels of affected cats, causing severe lung disease, heart failure and damage to other organs in the body.
Disease Information Sites
The American Heartworm Society has great information about heartworm disease in cats.
Today’s Veterinary Practice has an excellent page covering the misconceptions about heart disease in cats and does a great job covering the differences in how cats are affected by heartworms compared to dogs.
The only support groups I was able to find for heartworm are groups for dog owners. Heartworm presents very differently in cats and cats do not currently have any treatment options available other than prevention. You could search for and join a group for this, but it’s unlikely to provide any real support for a cat owner.
Special Hearts: Cats with Heart Defects or Diseases is a great group for support but heartworm doesn’t come up very often as a topic since it’s so rarely diagnosed in cats.
Cats with Multiple Medical Conditions is an excellent Facebook group that can possibly help with heartworm in cats.
Cat Health and Behavior is an email-based support group for general issues. There may be members of that group who have experience with heartworm.