instruction: what is the maximum hospital cost for a procedure that involves cardiac mapping during this year?
response: SELECT MAX(t1.c1) FROM (SELECT SUM(cost.cost) AS c1 FROM cost WHERE cost.hadm_id IN (SELECT procedures_icd.hadm_id FROM procedures_icd WHERE procedures_icd.icd9_code = (SELECT d_icd_procedures.icd9_code FROM d_icd_procedures WHERE d_icd_procedures.short_title = 'cardiac mapping')) AND DATETIME(cost.chargetime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-0 year') GROUP BY cost.hadm_id) AS t1