An elderly patient comes into the emergency department (ED) with shortness of breath.

Impending myocardial infarction is reported with I21.3 for a myocardial infarction (acute). The shortness of breath, which is a symptom, is coded separately as R06.02. According to ICD-10-CM guidelines, when a definitive diagnosis is established, the diagnosis code is sequenced first followed by symptom codes.References: ICD-10-CM (current year), Chapter 9: Diseases of the Circulatory System (I00-I99), ICD-10-CM Official Guidelines for Coding and Reporting, Section I.C.9.e.4.