2626
The duration of the examination and the mean ejection fraction ( EF ) were 16 . 4 + / - 6 . 1 minutes and 60 + / - 9 % , respectively .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 None