Binding Lost Focus on ListView in purely mvvm based application.

I have a ListView (having GridView and two columns to display data) bound to an observable collection.

Observable collection has KeyValuePair of Int,Bool. This bool Value is shown as a Checkbox in the ListView.   I tried attaching 'EventTrigger' based on 'LostFocus' command binding to the ListView , BUT it is not firing. Instead the command fires when i check/uncheck items inside the ListView (which is not required).  

Is there any way I can bind LostFocus command binding ,  as soon as i click out of the ListView (for a purely mvvm based application) 

Thanks.