title: Pediatric cardioplegia strategy results in enhanced calcium metabolism and lower serum troponin T.
abstract: BACKGROUND
  Pediatric myocardium is unique from mature myocardium; thus, the use of adult cardioplegia for pediatric cardiac operations may provide suboptimal myocardial protection. We evaluated our standard adult cardioplegia (AC; modified Buckberg) and a pediatric cardioplegia (PC) solution (del Nido solution, Baxter) in vitro in rat cardiomyocytes and compared short-term outcomes in pediatric cardiac surgical patients.
  
  
  METHODS
  Contractions, intracellular calcium, and action potentials were recorded from isolated rat cardiomyocytes exposed to PC or AC, followed by reperfusion. Pediatric patients (n = 118) undergoing cardiac operations using PC (group PC, n = 59) or AC (group AC, n = 59) were matched 1:1 for age, diagnosis, and duration of cardiopulmonary bypass.
  
  
  RESULTS
  PC-perfused rat ventricular cardiomyocytes had lower diastolic calcium during cardioplegia and early reperfusion than AC-perfused cardiomyocytes. Cardiomyocytes remained excitable despite introduction of AC but not PC. The mean age in each pediatric group was 3.7 years (range, 3 days to 17 years; p = 0.95). Median serum troponin T levels at intensive care admission were significantly lower in group PC (0.83 +/- 0.25 microg/L) than in group AC (13.8 +/- 12.7 microg/L, p = 0.0001), which persisted at 24 hours postoperatively. There were no significant differences in duration of intubation or length of stay in intensive care or the hospital.
  
  
  CONCLUSIONS
  Pediatric cardioplegia is associated with reduced intracellular diastolic calcium during arrest and reperfusion and more complete arrest during exposure in rat cardiomyocytes. Pediatric patients receiving pediatric cardioplegia had reduced troponin T release compared with those receiving adult cardioplegia.
authors.affiliation: Department of Pharmacology, Izaak Walton Killam Health Centre, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: J Darcy
authors.initials: JD
authors.lastname: O'Brien
authors.forename: Susan E
authors.initials: SE
authors.lastname: Howlett
authors.forename: Hayley J
authors.initials: HJ
authors.lastname: Burton
authors.forename: Stacey B
authors.initials: SB
authors.lastname: O'Blenes
authors.forename: D Sharon
authors.initials: DS
authors.lastname: Litz
authors.forename: Camille L Hancock
authors.initials: CL
authors.lastname: Friesen
mesh_terms: D000200:Action Potentials; D000328:Adult; D000818:Animals; D001283:Atrioventricular Node / Q000601:surgery; D002118:Calcium / Q000378:metabolism*; D006348:Cardiac Surgical Procedures; D002648:Child; D006324:Heart Arrest, Induced / Q000379:methods*; D006343:Heart Septal Defects / Q000601:surgery; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D008297:Male; D032383:Myocytes, Cardiac / Q000166:cytology / Q000473:pathology / Q000502:physiology; D051381:Rats; D011916:Rats, Inbred F344; D020107:Troponin T / Q000097:blood*
chemical_list: D020107:Troponin T; D002118:Calcium