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 elevationmyocardial 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 orbradycardia (heart rate<50 beats/min, blood pressure<90/60mmHg); 6) contraindicationsto beta blockers or allergy to any ingredient of beta blocker; 7) active asthma shouldbe 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 thisstudy (for example, patients with a higher risk of cardiogenic shock, etc.)