Here is the design of a clinical trial:

Official Title: A Multi-Center Study on the Metoprolol Optimal Dosing Pathway of Metoprolol Application in Chinese Patients With Acute Coronary Syndrome

Included conditions:
- ACS - Acute Coronary Syndrome

Study Armgroups:
- {'label': 'Metoprolol interventional group', 'type': 'EXPERIMENTAL', 'description': 'This is a multi-center, prospective, open label, single-arm interventional study.\n\nPatients hospitalized for ACS, fulfilling all of the inclusion criteria and none of the exclusion criteria can be enrolled in this study.', 'interventionNames': ['Drug: Metoprolol']}

Interventions:
- {'type': 'DRUG', 'name': 'Metoprolol', 'description': 'Patients with acute coronary syndrome take metoprolol during hospital and after discharge in the optimal dosing pathway.', 'armGroupLabels': ['Metoprolol interventional group']}

Primary Outcomes:
- {'measure': 'percentage of patients achieving target dose', 'description': 'The percentage of patients achieving target dose of 95mg/d at the time of discharge', 'timeFrame': '1 month'}

Please estimate the sample size based on the assumption: 
The significance level is set at 95% confidence interval (Z=1.96), and the precision (half-length of 95% CI) is between 2.5% to 1.9%.
âSample size justification
          This is a study to investigate the percentage of patients achieving target dose during hospitalisation. Assuming the percentage of patients achieving target dose during hospitalisation to be around 80%â90%, 1000 patients will allow it to be estimated with a precision (ie, half-length of 95% CI) of 2.5% to 1.9%. A simple formula14 can be used for sample size calculation for the study estimating population prevalence as follows:
          
n=Z2P(1-P)d2

          where n=sampleâsize, Z=Z statistic for a level of confidence (Z=1.96 for 95% CI), P-=expected prevalence or proportion, d=precision.