Can anyone explain the significance of the yetzer hara having left Itzchok avinu? Rashi says that the parsha says "I am the G-d of Yitzchok" even though he was still living because he was blind and house bound and his yetzer hara was gone. What are the implications of this I should appreciate? And if he was basically dead already why was he still physically living?

It makes me nervous because my own path has been to whittle away at the yetzer, different than most people, so I'm wondering what the implications are.

Maybe it means that once the yetzer is gone Hashem can pretty much count on the person staying on a derech so reputationally it's okay to associate His name with the person?