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: Resting values of LVEF , FS , + LVdP / dt , and MBP remained unchanged whatever the drug and the dosing regimen , whereas resting HR was significantly and dose - dependently lowered after dronedarone and to a lesser extent after amiodarone .
### Output Text:
Resting values of LVEF , FS , + LVdP / dt , and MBP remained unchanged whatever the drug and the dosing regimen , whereas resting HR was significantly and dose - dependently lowered after <span class="chemical">dronedarone</span> and to a lesser extent after <span class="chemical">amiodarone</span> . 