Public Function GetSelectedSlicerItems(SlicerName As String) As String
Dim SL As SlicerCacheLevel
Dim sI As SlicerItem

Set SL = ActiveWorkbook.SlicerCaches(SlicerName).SlicerCacheLevels(1)
For Each sI In SL.SlicerItems
If sI.Selected = True Then
GetSelectedSlicerItems = (sI.Value)
End If
Next
End Function

Dim sValue As String
sValue = GetSelectedSlicerItems("Slicer_HeaderTitle")