DukeCry is a nice little Addon that will inform others about your health dropping below a certain threshold .
Configure with /dukecry , also accessible vie the Interface/Addons settings panel.
You can configure the message used, the health threshold ( % value of total health ), the cooldown ( specifies how long the Addon will wait to re-broadcast your message when you are still under the threshold), and who you want to alert.
The options for reporting are : /say, /yell, /guild, /party, /raid, your default chatframe, and /whisper (you have to set the whispertarget, the person you want to whisper).
TODO: Add DataLibBroker compatability, add same alert functions for Mana ( nice for healers ) , etc
Nicely fills a gap left by the latest patch!