Tables without Primary keys SQL Server 2008

SELECT SCHEMA_NAME(o.schema_id) AS [Schema]

,object_name(i.object_id ) AS [Tables]
,p.rows AS ROWS
,user_seeks
,user_scans
,user_lookups
,user_updates
,last_user_seek
,last_user_scan
,last_user_lookup
, i.type_desc
FROM sys.indexes i

INNER JOIN sys.objects o ON i.object_id = o.object_id

INNER JOIN sys.partitions p ON i.object_id = p.object_id AND i.index_id = p.index_id

LEFT OUTER JOIN sys.dm_db_index_usage_stats ius ON i.object_id = ius.object_id AND i.index_id = ius.index_id
WHERE i.type_desc = 'HEAP'
ORDER BY user_updates Desc