Yes, they can! They didn't used to think cats got them, but studies in the last few years have shown that although it's more common in dogs, cats can indeed get heart worms, too, and unfortunately, they're often more deadly and more difficult to treat according to one article I just pulled up. My doctor warned me about them in my inside kitty a couple years ago and I had absolutely no idea it was even possible, so I read up on them at the time. Here a couple pages I pulled up with info about it (there's some great info about heart worms, in general, too, so they're worth looking at):
http://www.sniksnak.com/cathealth/heartworms.html http://www.purdue.edu/UNS/html4ever/...on.feline.html http://www.dr-dan.com/heartwor1.htm