instruction: what is the average value of heartrate of patient 002-44624?
response: SELECT AVG(vitalperiodic.heartrate) FROM vitalperiodic WHERE vitalperiodic.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '002-44624')) AND NOT vitalperiodic.heartrate IS NULL