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: Decreased left ventricular systolic function was demonstrated in 5 ( 14 % ) patients , but in none of the controls ( p = 0 . 055 ) .
### Output Text:
Decreased left ventricular systolic function was demonstrated in 5 ( 14 % ) patients , but in none of the controls ( p = 0 . 055 ) . 