Real World Assessment of Effects of Beta-blockers on Patients With Acute Coronary Syndrome

Inclusion Criteria: * Age ≥ 18 years * Patients diagnosed as acute coronary syndromes including acute ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevated acute coronary syndrome (NSTE-ACS) * Patients or whose legal representatives signed written informed consent form Exclusion Criteria: Patients should been excluded if they meet any of the following exclusion criteria: * Patients with contraindications to the application of beta blockers, including: 1) cardiogenic shock or heart failure (Killip grade \> II level);2) sick sinus syndrome; 3) II degree atrioventricular block;4) unstable decompensation of cardiac failure (pulmonary edema, hypotension or low perfusion); 5) symptomatic hypotension or bradycardia (heart rate\<50 beats/min, blood pressure\<90/60mmHg); 6) contraindications to beta blockers or allergy to any ingredient of beta blocker; 7) active asthma should be treated by inhalation preparation treatment * Pregnant or lactating women * Patients without signed written informed consent * Patients who was considered by the researcher inappropriate to participate in this study (for example, patients with a higher risk of cardiogenic shock, etc.)