As a healer, you run with a heroic dungeon group (tank + rogue, mage and hunter). Adds continuously appear immediately after the last (based on timer) and you have little to zero time to regenerate mana. Your goal is to keep everyone alive. WoWhead has a decent write up about the healer scenarios.
Things I noticed.
- Vuhdo does not recognize the scenario tank as a tank. Not bad, but annoying because I like to use this different window to throw the Prayer of Mending frisbee at.
- Bronze is rather easy. Did it in my first pass as Discipline. Silver included a couple AOE options that require mitigation. I found myself throwing Pain Suppression on the tank when he got really bad.
- Mana was always an issue. I had to make sure my pet was ready for the mana regen.
Gold has been impossible to complete so far. Reading WoWhead, it appears that an interrupt is necessary to avoid the Sonic Blast damage.