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: Takotsubo syndrome ( TS ) , also known as broken heart syndrome , is characterized by left ventricle apical ballooning with elevated cardiac biomarkers and electrocardiographic changes suggestive of an acute coronary syndrome ( ie , ST - segment elevation , T wave inversions , and pathologic Q waves ) .
### Output Text:
Takotsubo syndrome ( TS ) , also known as broken heart syndrome , is characterized by left ventricle apical ballooning with elevated cardiac biomarkers and electrocardiographic changes suggestive of an acute coronary syndrome ( ie , ST - segment elevation , T wave inversions , and pathologic Q waves ) . 