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: We conclude that cardiac pacing during resuscitative efforts in pediatric patients suffering from acute myocardial dysfunction may not have long - term value in and of itself ; however , if temporary hemodynamic stability is achieved by this procedure , it may provide additional time needed to institute other therapeutic modalities .
### Output Text:
We conclude that cardiac pacing during resuscitative efforts in pediatric patients suffering from acute myocardial dysfunction may not have long - term value in and of itself ; however , if temporary hemodynamic stability is achieved by this procedure , it may provide additional time needed to institute other therapeutic modalities . 