Definition, classification, and pathophysiology of acute coronary ischemic syndromes.

The acute coronary syndrome (ACS) is now used to describe a spectrum of clinical presentations that share an underlying pathophysiology, replacing the previous nomenclature of ischemic chest pain. The accurate diagnosis and proper management of patients with these entities require the emergency medicine physician to consider the entire spectrum of ACS, with emphasis placed on early diagnosis and rapid treatment. Each of these syndromes has its own prognosis, pathophysiology, and specific management strategy.