My dog has heart worm. Please answer—10 points.?

My dog has heart worm and she is going to the vet tomorrow. In order to kill the heart worm, they are going to have to inject her with arsenic (Main Ingredient in rat poison). The vet said that this process is risky. So my question is has anyone had there dog treated for heart worm and how were the results.. Please answer, i am worried sick! And i already payed 600 dollars, so there is no turning back..