[Dridzt]

local eventframe = CreateFrame("Frame")

eventframe:SetScript("OnEvent", 
	function(self,event,...)
		return self.event and self.event(...)
	end)
	
eventframe:RegisterUnitEvent("UNIT_HEALTH_FREQUENT","pet")

function eventframe.UNIT_HEALTH_FREQUENT(...)
	local hpRatio = UnitHealth("pet")/UnitHealthMax("pet") < 0.8 and print("Pet Health Low!")
end