Cara
When I worked with a holistic vet (Dr. Russell Swift), we treated 4 dogs for HW. We used homeopathy, raw diet, and different herbals (based on Hulga Clarke's protocol for parasites). Three went negative, and the fourth (which was a stray I rescued) did not, but he had no symptoms and there's a big difference between being heart worm positive and having heart worm disease. Heart worms don't reproduce in the animal, so if you just prevent reinfection by keeping the immune system strong (giving the dog a raw diet, avoiding vaccinations,for example), the worms there will eventually die and the animal will be free and clear.