Preflop, I tend to just dump it once he min re-raises. Difficult though because you're getting 5:1 on the call - but if he has Ax or a pocket pair you aren't getting the right price to see the flop.

On the flop, I would call. Top pair + flush draw + gutshot is a very strong hand, even more so heads up. I would say he has a flush draw, Ax with no draw or a pocket pair - this sort of AI overbet on the flop is very often a draw thata doesn't want a call. The only hand you're really fearing is Ax with a better heart kicker but with this kind of draw I call every time.