Are Resto Druids Up To Heroics?

Recently, I spent a while arguing with a friend on the guild mailing list about whether resto druids could really hold their own in Heroics, and other instances. I've never had a problem healing standard 5-mans as Leafy, and Kara has been pretty straight forward as well. A couple of Heroic Setthek Halls runs I've done of late made me feel pretty confident, too. Now I'm beginning to wonder if he was right.

Last night in the Slave Pens was a complete Grindhouse. I was below 20% durability before we reached the second boss, over two hours into the run. Now, two of those deaths were my own fault, through not knowing the instance and the pull pattern (I haven't run it since I last did it on non-Heroic mode). But most of them were to do with loose mobs, Hunters feigning and a lack of any form of realistic aggro dump. Eventually we had to call it just prior to the last boss when one of the hunters just had enough.

And I came away seriously worried about my own ability to heal heroics. I just die too easily, and keep everyone waiting while I run back. The lack of an out of combat res wasn't actually the issue - there was only one situation where a party member died and I didn't. And there were times when I just couldn't keep up with the damage to the tank.

So here's the thing - in your experience, can deep resto druids really cut it as heroic healers, or do they need an off-healer to make it work?