Approximately 70% of these will have NSTE-ACS.9 Patients with NSTE-ACS typically have more comorbidities, both cardiac and noncardiac, than patients with STEMI. *Estimate includes secondary discharge diagnoses. The hallmark of ACS is the sudden imbalance between myo- cardial oxygen consumption (MVO2 ) and demand, which is usuallytheresultofcoronaryarteryobstruction.Theimbalance may also be caused by other conditions, including excessive myocardial oxygen demand in the setting of a stable flow-lim- iting lesion; acute coronary insufficiency due to other causes (eg, vasospastic [Prinzmetal] angina [Section 7.11], coronary embolism, coronary arteritis); noncoronary causes of myo- cardial oxygen supply-demand mismatch (eg, hypotension, severe anemia, hypertension, tachycardia, hypertrophic car- diomyopathy, severe aortic stenosis); nonischemic myocardial injury (eg, myocarditis, cardiac contusion, cardiotoxic drugs); and multifactorial causes that are not mutually exclusive (eg, stress [Takotsubo] cardiomyopathy [Section 7.13], pulmonary embolism, severe heart failure [HF], sepsis).41 3. Initial Evaluation and Management 3.1. Clinical Assessment and Initial Evaluation: Recommendation Class I 1. Patients with suspected ACS should be risk strati- fied based on the likelihood of ACS and adverse Table 2. 