I'm certainly no expert, but I do think this may work...
Assuming you auto generate defects on test failure, the "History" tab in a test case will contain the text "...Defect xx: This test case failed so defect..." and so on..
So, you could create a custom chart with drilldowns etc and use an SQL query to select these test cases for you. I've checked this SQL and it seems to work for me, but I'm yet to create the custom chart - I guess this is something the SmartBear guys can help with..
Select * FROM dbo.View_TestCases WHERE ProjId = xxxxx AND NotesDescription LIKE '%This Test case failed%' AND StatusCode='Passed'
Including StatusCode='Passed' in the query will only return records with a current status of passed but they would have failed at some point in the past.
Hope this helps..
