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: Angiotensin - converting enzyme inhibitors and angiotensin II receptor - blocking drugs hold promise in atrial fibrillation through cardiac remodelling .
### Output Text:
<span class="chemical">Angiotensin</span> - converting enzyme inhibitors and <span class="chemical">angiotensin II</span> receptor - blocking drugs hold promise in atrial fibrillation through cardiac remodelling . 