When the hero has a little life> 20hp, the screen turns red and start flashing, how to do it in full screen?
and how to add the sound of the heartbeat
Seeing that you posted in the scaleform topic, I guess you want to use flash for that.
You can make your effect in the flash video and call an actionscript function to trigger it.
The sound of a heartbeat can be played via the playsound flowgraph node.