This study is to test the feasibility and tolerability of the metoprolol optimal dosing pathway by observing the percentage of patients achieving target dose followed the pathway on ACS patients during hospitalization.

Acute coronary syndrome(ACS) is one of the main manifestations of cardiovascular disease and one of the main causes for hospitalization in adults.

Previous studies showed that β-receptor blockers can reduce ACS patients' cardiovascular risk in both acute phase and secondary prevention. We summarized the metoprolol optimal dosing pathway based on Chinese and foreign guidelines as well as Chinese clinical practice.

Primary endpoint is the percentage of patients achieving target dose at time of discharge.

Secondary endpoints are the mean HR & BP at discharge and during the follow up period of the Patients who have achieved target dose at discharge.

Inclusion Criteria:

• Aged 18 years or above;
• Hospitalized due to acute coronary syndrome;
• Able and willing to provide written informed consent and to comply with the study.

Exclusion Criteria:

• Cardiac shock;
• Unstable heart failure;
• Beta-agonist therapy on a continuous or intermittent basis;
• Hypotension (BP<90/60 mmHg) or bradycardia (HR<50 bpm) with symptoms;
• Sick sinus syndrome;
• Ⅱ~Ⅲ atrioventricular block;
• Killip >Ⅱ;
• Suspected acute myocardial infarction with heart rate<45 beats/min, P- R interval>0.24 sec or systolic blood pressure <100 mmHg;
• Existing contraindication for metoprolol or allergic to metoprolol or any excipients;
• Participation in another clinical study with an investigational product during the last 3 months;
• Previous enrolment in the present study;
• Subjects the investigator thinks not suitable for this study. E.g. cancer etc.;
• Inability to sign the informed consent form;
• Pregnancy or lactation.