It looks very much like West has led from a doubleton spade and East has ♠A K Q 8 x. In other words, you can’t let them in with the ♣A. It seems easy enough to take five heart tricks unless East has an unexpected J–x–x–x in that suit.
After winning the first spade, you have four tricks on top — the spade from the first trick and three diamonds. So you need five heart tricks.
The proper play for five heart tricks with this combination, given one return entry to the closed hand (the ♦ Q), is to start with the ♥ Q. If East shows out, you have the wherewithal to take two heart finesses. If you start by leading low to the king and then low to the queen, you can pick up J–x–x–x with West, but not J–x–x–x–x.
No sweat if you were familiar with the combination. Assuming you were, of course, think of it as a good lesson for your partner!
The full deal: