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.

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.

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 μg/L) than in group AC (13.8 ± 12.7 μg/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.

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.