Question: When coding heart failure and the provider states that the patient has systolic heart failure with exacerbation, would the correct code be I50.21 (Acute systolic (congestive) heart failure)? Does exacerbation mean acute? Louisiana Subscriber Answer: Not necessarily. Exacerbation just means a flare-up—that something is making the heart failure worse. Acute systolic heart failure would mean “This patient’s heart was fine yesterday, but now it isn’t.” If that’s what’s happening here, then yes I50.21 would be appropriate. However, if the patient has chronic heart failure, then it should probably be I50.20 (Unspecified systolic (congestive) heart failure). Don’t miss: Acute heart failure develops suddenly, and the symptoms are initially severe. On the other hand, chronic heart failure usually develops slowly, over time. Those who have chronic heart failure usually have a previous history of heart failure and are on long-term management such as medications to control the heart failure.