I asked several people about this, and all of them said, `No’. But according to the Oxford Collocations Dictionary, it is all right to say, `heartfelt congratulations’. You should remember, however, the word `heartfelt’ meaning `sincere’ is used when we are deeply stirred or moved by something. It is usually associated with emotions linked with sadness. One can talk about `heartfelt sympathies’, `heartfelt condolences’, etc. But it is also possible to say, `heartfelt thanks’ and `heartfelt joy’. `Hearty’, on the other hand, suggests high spiritedness, vigour and energy. You can talk about `hearty laughter’, `hearty appetite’, etc. You cannot say `hearty condolences’.