called and left no message

Called at around 1pm ET on 7-22-10; Caller ID said "Unavailable" so I didn't pick up.  When I played back msg, all I could hear was what sounded like someone out of breath from running/walking around.  Heard 4 heavy breaths and then he hung up.  Pretty sure it wasn't your usual obscene call but I still hate these annoying, intrusive calls.