Caber can only be bad for the heart when taken at Parkinson's treatment levels (10-100x what we take). These ergot derived Dopamine agonists cause back flow problems in the heart valves (valves don't close properly). But not at BB doses.
And nope, I don't guess we need any prolactin. It's not like estrogen in that way, that we need a little.
On the question about if it's good to take when not on 19-nors like Deca or Tren, yes. All androgens affect Dopamine receptors over time and can leave you feeling flat and burnt out. So a little Prami works wonders. But too much over too long makes you feel like shit too, at least IME.