In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: The patient was admitted to the hospital , anticoagulated with unfractionated heparin , and given intravenous diltiazem for rate control and intravenous amiodarone for rate and rhythm control .
### Output Text:
The patient was admitted to the hospital , anticoagulated with unfractionated <span class="chemical">heparin</span> , and given intravenous <span class="chemical">diltiazem</span> for rate control and intravenous <span class="chemical">amiodarone</span> for rate and rhythm control . 