2♥ showed 5-5 or better in hearts and a minor, weak.
I have realised now that I was half asleep on this hand, and forgot partner held a minor as well as hearts. If I'd had been awake, I would have punted slam, which makes on a very fortunate layout. In the event, after opps bid to 4♠, I had to decide whether to go for a penalty or bid 5♥. After a bit of thought, I decided that getting +800 out of this was against the odds, but 5♥ was very likely to be there, so bid it.
It turns out that +800 is there, it requires accurate defence. I have to underlead my heart honors to partner's king, then she has to switch to a diamond. We take one heart, two diamonds, a diamond ruff, and two clubs. Whether we would find that defence is another matter. Put club Qxx in one hand instead, and we only get +500, with 5♥ still cold.