Some more detail about the agreements of EW that may help put things in focus.
They don't have a CC, but agreed to play a well known 4-card major system which is habitual for W and occasional for E (who usually plays a strong club system but has much the same agreements once past game level). Few and antiquated conventions.
sanst, on 2019-February-07, 03:57, said:
It has nothing to do with directing, but I’m quite surprised by the auction. Why didn’t W call 2NT, which would have given E the opportunity to show his hearts?
Cyberyeti, on 2019-February-06, 13:50, said:
What did 3N show ? was kokish being played etc ?
The 2
♣ opening here is the Crodo convention, not mentioned by name but correctly described in the explanations. The 2
♦ reply is a weak negative (denies any of 7/8 HCP, an Ace, 2 Kings), 2NT is a stronger negative (one or more of previous) and suit shows an Ace. After a negative reply, the asker is expected to either signoff in game/slam, or ask kings (no use here) or show a suit (not necessarily the longest) in which she requests help in honours. So her options were 3NT to play or 3
♦ looking for the Q (but maybe she forgot that detail of the convention or thought her partner would have done).
The convention ends when she places game or slam, so partner's 4
♥ is a natural free bid and somewhat unexpected.
Cyberyeti, on 2019-February-06, 13:50, said:
There is no way in this world I'm passing 4♥, I don't even consider it, but it is possible to stop short of a slam.
With their agreements it's not easy to see any middle ground between pass and slam. 4NT would be plain Blackwood, 5
♥ would invite to bid slam with 2 top honours, 5NT probably a grand slam try - all inapplicable here, at least if taken literally.
So I suspect that if a poll had been held among peers (without mentioning the BIT) the bids that emerge as logical would be just Pass, 6
♥ and 6NT. Although I too would never pass 4
♥ and nor do I think West would.