The trivia item below may give away important plot points.
When Meredith talks to Denny about Izzie, Denny says "You know Izzie pretty well, right? You think if I went to her and I said 'hey this is going to be bad for your career. '... You think that'll have any effect at all?" Two episodes later (ep 25: 17 Seconds) Denny warns Izzie that her plan for his LVAD will be the end of her career and she says she does not care.