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: Patients with New York Heart Association classes II to IV CHF and left ventricular ejection fractions of no greater than 0 . 30 ( n = 3164 ) were randomized and followed up for a median of 46 months .
### Output Text:
Patients with New York Heart Association classes II to IV CHF and left ventricular ejection fractions of no greater than 0 . 30 ( n = 3164 ) were randomized and followed up for a median of 46 months . 