Heart deteriorating, should we do CPR if it fails?

Denise's cardiac status is deteriorating. The doctor called to say that if her heart arrests, it may not benefit her to try CPR, as the heart is so weak it may not be able to get enough oxygen to the vital organs, brain included. This is the same conversation we had last Sunday. He didn't know that we should get her out of the Morphine haze (no Ativan drip, that was a mistake in my last post) in order to ask her what her preference is. She's not a good candidate for any type of surgery that may be needed. But she probably can't handle another hit like she had a little over a week ago, cardiac status being what it is. In the mean time, they're trying to do everything they can, and being aggressive about it. But if the heart stops, we have to decide whether or not to try CPR. They might try using a drug called Dobutimine, but I haven't had time to figure it out. I just wanted to get this simple post out to you. I'm sick and do is Jacob, so I took the day off work. This is turning out to be one very stressful morning.
Pray that the heart doesn't stop, and that Denise can heal.