It varies by carrier. Medicare requires us to use 33999. Most of the healthplans accept that code.
Payable ICD-9 codes are (but not limited to):
Cardiogenic shock 785.51
Heart failure, systolic, acute 428.21
Heart failure, systolic, acute on chronic 428.23
Heart failure, combined, acute 428.41
Heart failure, combined, acute on chronic 428.43
Functional disturbances following cardiac surgery 429.4
(cardiac insufficiency/heart failure following cardiac surgery or due to prosthesis)
Cardiac complications 997.1
(cardiac arrest, cardiorespiratory failure, heart failure, during or resulting from a procedure)