[JayKon]

Call and here is why.

The pot is $1,225 and it costs you $300 to call. Thats 4-1 pot odds.

So, what could he have bet with? A flush, set, two pair, top pair, other pair?

For just the turn:

Assume a flush (40%) 7 remaining hearts out of 45 unseen cards ~1 in 6.5
Assume a set, or two pair, no heart (20%) 9 remaining hearts, plus the 3 non-heart K's out of 47 unseen cards ~1 in 4
Assume AQ (15%)the hearts and K's are outs. (same for 35%)
Assume KQ, QJ, or Qx (10%) add 3 more A's to the outs for 15 out of 47 unseen cards ~1 in 3.
Assume a stone cold bluff that only wins if he pairs and you don't ~10%.

7 outs 15% (1 in 6.5) 40% of the time = 2.8
12 outs 25% (1 in 4) 35% of the time = 4.2
15 outs 33% (1 in 3) 15% of the time = 2.25
41 outs 87% (41 in 47) 10% of the time = 4.1 = 13.35 outs

13/47 ~= 1 in 3.5 and the pot is offering ~1 in 4

Your opponent didn't bet enough to make taking a card off incorrect.