9791
According to pilot experiments which considered various durations of global no - flow ischemia ranging from 10 to 20 minutes , two durations were chosen for the present study : 20 minutes ( group 20 ) in which ventricular fibrillation ( VF ) was the predominant form of arrhythmias , and 18 minutes ( group 18 ) in which the prevalence of VF was markedly lower despite the small difference in the duration of ischemia .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
 Entities:  
Answer:
 None