Blood Bath, before it was "merged" with Bloodrage, had a unique sound which played whenever it healed you. This sound is now unused since the rework.

I suggest using that sound again, for the same purpose as before, trigger whenever getting healed, this time with Bloodrage. It would be audible only to the hero who gets healed by it, similar to how Blood Bath was only audible to Bloodseeker.

Here is a small demonstration how it would be, just like with the old passive Blood Bath.