So you are dealt another card from a 51 card deck due to the first card being already picked? I am going to answer for if you drew neither a king or heart and then king or heart, then finally if you drew a King which is also a heart.
P(K or H) [Where the initially drawn card isn't K or H) = 13/51 + 4/51 - 1/51 = 16/51
P(K or H) [Where the initially drawn card is only K) = 12/51 + 4/51 - 1/51 = 15/51
P(K or H) [Where the initially drawn card is only H) = 13/51 + 3/51 - 1/51 = 15/51
P(K or H) [Where the initially drawn card is both K and H) = 12/51 + 3/51 - 0 = 15/51
If I may have misunderstood your question, and you are asking the initial card from a 52 card deck, then your answer is absolutely correct.