As an opening Edit
A 3♥ opening is preemptive in every system.
As a response Edit
1♣/1♦ - 3♥ is a double jump shift, which is either a weak jump shift, showing less than 6 HCPs and 7 ♥s, or a splinter showing support and void or singleton in ♥s.
To a 1♥ opening Edit
1♥-3♥ is a double raise, usually a limit raise.
To a 1♠ opening Edit
1♠-3♥ is a jump shift, which may be played as weak, showing less than 6 HCPs and 7 ♥s, or strong, showing a ♥ single-suiter with slam interest.
The 3-level responses of a 1NT opening have many possible meanings, which depend on agreements.
To a strong 2♣ opening Edit
A jump response to a strong 2♣ opening shows a very strong single-suiter and slam interest.
To a weak 2♥ opening Edit
A single raise of a weak two bid is preemptive and to play.
This shows a strong hand and a self-sufficient suit, and is forcing.
As an overcall Edit
A jump overcall of 3♥ is usually equivalent to a 3♥ opening, which is preemptive.