In simple words: During a heart catheterization procedure for a congenital heart defect, the doctor measures the amount of blood pumped by the heart using a special technique involving injecting a substance and measuring its temperature or concentration.

Cardiac output measurement(s), thermodilution or other indicator dilution method, performed during cardiac catheterization for the evaluation of congenital heart defects (List separately in addition to code for primary procedure). Notes: (Use 93598 in conjunction with 93593, 93594, 93595, 93596, 93597) (Do not report 93598 in conjunction with 93451-93461) (For pharmacologic agent administration during cardiac catheterization for congenital heart defect[s], use 93463) (For physiological exercise study with cardiac catheterization for congenital heart defect[s], use 93464) (For indicator dilution studies such as thermodilution for cardiac output measurement during cardiac catheterization for congenital heart defect[s], use 93598) (For contrast injections during cardiac catheterization for congenital heart defect[s], see 75825, 75827, 93563, 93564, 93565, 93566, 93567, 93568, 93569, 93573, 93574, 93575, 93584, 93585, 93586, 93587, 93588) (For angiography or venography not described in the 90000 series code section, see appropriate codes from the Radiology section and the Vascular Injection Procedures subsection in the Surgery/Cardiovascular System section) (For transseptal or transapical access of the left atrium during cardiac catheterization for congenital heart defect[s], use 93462 in conjunction with 93595, 93596, 93597, as appropriate).

Example 1: A pediatric patient with Tetralogy of Fallot undergoes cardiac catheterization, and code 93598 is used alongside the primary procedure code to report the cardiac output measurement using thermodilution., During catheterization for an atrial septal defect, the physician measures cardiac output using an indicator dilution method, reported with 93598 in addition to the primary catheterization code., A newborn with transposition of the great arteries undergoes cardiac catheterization, including cardiac output measurement via thermodilution, coded with 93598 and the appropriate primary procedure code.

Documentation should include details of the cardiac catheterization procedure, the method used for cardiac output measurement (e.g., thermodilution), the results of the measurement, and any associated diagnoses or procedures.

** Ensure documentation clearly indicates the method used for cardiac output measurement.