title: Cardiac dysfunction and inefficiency after substrate-enriched warm blood cardioplegia.
abstract: OBJECTIVE
  The study assessed the outcome after prolonged warm continuous antegrade blood cardioplegia (WCBC) with substrate enrichment, in terms of mechanical performance and mechanoenergetic efficiency.
  
  
  METHODS
  WCBC was given for 3 h to three groups of pigs on cardiopulmonary bypass; WCBC alone (n=7), WCBC+glucose and insulin (+GIK, n=7) and WCBC+L-glutamine (+GLN, n=7). Cardiac systolic and diastolic function, pressure-volume area (PVA) and myocardial oxygen consumption (MVO(2)) were assessed before, and twice after WCBC using pressure-conductance catheter, coronary flow-probes and O(2)-content difference.
  
  
  RESULTS
  In the WCBC, +GIK and +GLN groups respectively, the following parameters decreased after WCBC compared to baseline: left ventricular developed pressure by 26, 19 and 25% (P<0.001); dP/dt(max) by 36, 37 and 34% (P<0.001); preload recruitable stroke work by 35, 41 and 28% (P<0.001); mechanoenergetic efficiency (PVA/MVO(2)) by 44, 41 and 22% (P<0.001). End-diastolic stiffness increased early after WCBC in the WCBC and +GLN groups, while it was unchanged in the +GIK group (P=0.032).
  
  
  CONCLUSIONS
  Despite continuous aerobic conditions and additional substrates, post-WCBC cardiac contractile function and mechanoenergetic efficiency was severely depressed. The results demonstrate the hazards of sustained normothermic hyperkalemic perfusion.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, University Hospital in Tromsø, Tromsø, Norway. christian.korvald@rito.no
authors.forename: C
authors.initials: C
authors.lastname: Korvald
authors.forename: O P
authors.initials: OP
authors.lastname: Elvenes
authors.forename: T
authors.initials: T
authors.lastname: Myrmel
authors.forename: D G
authors.initials: DG
authors.lastname: Sørlie
mesh_terms: D000818:Animals; D001769:Blood; D002314:Cardioplegic Solutions; D002315:Cardiopulmonary Bypass; D004734:Energy Metabolism; D005947:Glucose / Q000008:administration & dosage; D005973:Glutamine / Q000008:administration & dosage; D006324:Heart Arrest, Induced / Q000009:adverse effects / Q000379:methods; D006439:Hemodynamics; D007328:Insulin / Q000008:administration & dosage; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption; D011188:Potassium / Q000008:administration & dosage; D013552:Swine; D013696:Temperature; D016277:Ventricular Function, Left
chemical_list: D002314:Cardioplegic Solutions; D007328:Insulin; D005973:Glutamine; D005947:Glucose; D011188:Potassium