Question: If the cardiologist documented that the patient has a diagnosis of cardiac arrest due to an underlying cardiac condition, which ICD-10 code should we report? Ohio Subscriber Answer: If the patient has cardiac arrest due to an underlying cardiac condition, then you would report I46.2 (Cardiac arrest due to underlying cardiac condition). On the other hand, if the patient has cardiac arrest due to “other” underlying condition, then you would report I46.8 (Cardiac arrest due to other underlying condition). Don’t miss: If the cause of the cardiac arrest is unspecified, then you would report I46.9 (Cardiac arrest, cause unspecified). Tip: You should work with your cardiologist to ensure you have easy access to documentation of the underlying cause of the cardiac arrest so you may code more accurately. Not only will you need to know whether the underlying cause is “cardiac” or “other” to choose between I46.2 and I46.8, but you’ll also need to know the specific underlying condition so you may report it separately. Cardiac arrest defined: Cardiac arrest refers to a sudden loss of heart function caused by the heart’s electrical system (that is, arrhythmia). Cardiac arrest differs from a heart attack, which results from a blockage that prevents blood from flowing to the heart.