Mysql takes up to 50% cpu after aborting DELETE query
Since sv is a MyISAM table, I would expect a backlog of DB Connections attempting to write to the table in a high-traffic environment.

In fact, any DML (INSERT, UPDATE, DELETE) against the sv table will result in a full table lock on sv.

You should still run a CHECK TABLE sv; as a precaution.

Please keep in mind that data for MyISAM tables are never cached. It is possible that the OS is just swapping used memory as a result of the heavy activity against the MyISAM.

All you can really  do in that instance is reboot the OS