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 apical ballooning syndrome ( ABS ) is a recently described stress - mediated acute cardiac syndrome characterized by transient wall - motion abnormalities involving the apex and midventricle with hyperkinesis of the basal left ventricular ( LV ) segments without obstructive epicardial coronary disease .
### Output Text:
The apical ballooning syndrome ( ABS ) is a recently described stress - mediated acute cardiac syndrome characterized by transient wall - motion abnormalities involving the apex and midventricle with hyperkinesis of the basal left ventricular ( LV ) segments without obstructive epicardial coronary disease . 