How advanced is heartworm on a year old dog?

We just adopted a dog from the Humane Society. She is a year old and has heart worm. How advanced would the heart worm be in her and is the slow kill method logical?The "slow kill" method is placing her on heart worm preventative to prevent new worms from growing. The ones that are already alive will eventually die off and her body will get rid of them naturally.

I would have a vet evaluate the maturity of the worms she is carrying.While it is unlikely that a dog just a year old would have a heavy and mature heartworm load, it can happen. If the dog was infected as a young pup, it could be a year in duration for the infestation. Also, Humane societies are notoriously bad at knowing age. I your pup really a year? Likely, but not for sure.A vet evaluation is your best bet, but 80% chance slow kill method is ok.

Seek vet help.