With the opening style as given, partner is much more likely to have 5 hearts than 4, he will only have 4 if 3433 or 44(32) outside the 1N range. I think this is pretty close, it may matter whether you play weak or strong no trump here. If partner can't have a flat minimumk opener I prob bid 2♥, if he can I'm more inclined to bid 1N.