Single-dose versus multidose cardioplegia in neonatal hearts.
We designed an experiment to compare single-dose versus multidose cardioplegia (calcium 0.3 mmol/L) in neonatal rabbit hearts 1, 4 and 6 weeks of age at 25 degrees C and 32 degrees C. Isolated hearts had a stabilization period of retrograde perfusion, a working period, a period of ischemia with single or multidose cardioplegia, reperfusion, and a final working period. We measured hemodynamic recovery, creatine kinase during reperfusion, and coronary vascular resistance during administration of the cardioplegic solution. One-week and 4-week-old hearts exhibited better recovery with single-dose than with multidose cardioplegia. Six-week-old hearts, on the other hand, showed better recovery with multidose cardioplegia. Four-week-old hearts at 25 degrees C showed increased creatine kinase release with multidose cardioplegia. The 6-week-old hearts tended toward lower creatine kinase release with multidose cardioplegia. Coronary vascular resistance rose with subsequent administrations in 1-week and 4-week-old hearts at 25 degrees C but did not rise in 1- and 4-week-old hearts at 32 degrees C or in 6-week-old hearts at either temperature. On the basis of hemodynamic recovery, single-dose cardioplegia appears to provide better protection than multidose cardioplegia to 1- and 4-week-old isolated rabbit hearts. Once the rabbit has reached 6 weeks of age, multidose cardioplegia has some advantage over single-dose cardioplegia, similar to the findings in adult hearts. Creatine kinase release and coronary vascular resistance data corroborate the hemodynamic findings.
Kohman
L J
LJ
Department of Surgery, State University of New York Health Science Center, Syracuse 13210.
Veit
L J
LJ
D000818:Animals; D000831:Animals, Newborn; D002314:Cardioplegic Solutions / Q000008:administration & dosage*; D003331:Coronary Vessels / Q000502:physiology; D003402:Creatine Kinase / Q000032:analysis; D006321:Heart / Q000502:physiology; D006324:Heart Arrest, Induced / Q000379:methods*; D006439:Hemodynamics; D066298:In Vitro Techniques; D009206:Myocardium / Q000201:enzymology; D011817:Rabbits; D011897:Random Allocation; D014655:Vascular Resistance
D002314:Cardioplegic Solutions; D003402:Creatine Kinase