State controller John Chiang checked himself into the hospital in Forth Worth, Texas the day after Christmas.  The 46-year old was there visiting family and had experienced chest pains.  Jacob Roper is with the Controller's office.  He says tests showed evidence of a mild heart attack - and that Chiang responded well to treatment.   He was discharged on New Year's Day.  Roper says the Controller looks forward to returning to the office next week….and that he was in daily contact with staff members while he was in the hospital.  During that time, he also sent a letter to state agencies, warning them the state may have to send I-O-U's instead of checks as early as February first. Due to California's cash crunch.