An Opening Lead Problem

Last Saturday, I held:

A984
KQ76
T732
4

RHO opened 1 Spade. LHO bid 2 Clubs (game force). RHO raised to 3 Clubs. LHO bid 3 Hearts, and RHO closed out the bidding with 3 No Trump. What do you lead?

LHO's 3 Heart bid sounded like a Heart stopper, although it might be a 4-card suit. RHO's 3NT bid indicated a Diamond stopper. So should I have led a heart or a diamond, and if so, what card?

I reasoned that the club suit was probably running, so we need to make an aggressive lead. Since RHO bid spades, supported clubs and bid no-trump, he probably would be short in hearts. So I led the king of hearts, hoping he had no more than two hearts, and that either partner had the heart jack, or that if the opponents held it, declarer would have it singleton or doubleton, and partner would have the ten and possibly a long suit. This worked out perfecly, since the opponents' hands were:

T2
A42
64
AQJ765

KQJ63
J
AJ8
KT93

The king smothered the jack, and the defense had 4 heart tricks set up. Since the declarer only had 8 quick tricks, he just gave up the ace of spades and went down.