chest pain or anxiety

What would you have done, we have a resident in my facility who had a major MI a week and a half ago. They did a cardiac cath and put in a stint. She came back to the facility about a week ago. Last Friday when I came into work at 6am the night nurse told me the res. had c/o chest pain, but the nurse thought it was just anxiety so she gave her an ativan and maalox for indegestion. Well I called the cardiologist to give him an update and possibly get an order for nitro. since she had not come back with an order for any nitro. Well the cardiologist said due to the size of the stint he really did not want to give any nitro at this time but if the chest pain continued he may. He said for now just to monitor her. Well she was fine the rest of the day. I was off this weekend and when I came in on Monday, I guess she had continued to c/o chest pain so they had gotten a nitro order, but they had not given her any over the weekend, they had only given her ativan. As soon as I got there Monday morning she said she couldn't catch her breath and had chest pain she rated as an eight. I checked her vitals asked her if it was radiating anywhere, it wasn't and gave her a nitro. The order read give 1 every 15 min up to 4 times if no relief send to ER. Well she had 4 over an hour and her chest pain had not allieviated. I called the doctor and told him I was sending her to the ER. When the paramedics came she was in and out of A-fib and was admitted to the hospital. The nurse that had given her the ativan was there when I gave her the first dose of nitro and she said I would just give her and ativan. When I gave her the nitro anyway she went to the other nurse and said "Well if she doesn't want to benefit from 26 years of nursing experience, that's just ridiculous." But I don't feel you should disguise potential heart problems with ativan. What do you all think/