title: Myocardial metabolism and efficiency after warm continuous blood cardioplegia.
abstract: BACKGROUND
  Warm continuous blood cardioplegia (WCBCP) has been recommended during prolonged cardiac arrest to minimize functional deterioration. Myocardial metabolism and efficiency after this cardioplegic modality are not well described.
  
  
  METHODS
  Substrate oxidation, blood flow, and myocardial function were measured before, during, and after 3 hours of WCBCP in 7 pigs.
  
  
  RESULTS
  Free fatty acid and glucose oxidation decreased by 60% +/- 3.8% and 94% +/- 1.2%, respectively, during cardioplegia (both p < 0.05) and increased to 62% +/- 28% and 122% +/- 62% of baseline during the early recovery phase (p < 0.05 for glucose). One hour after WCBCP oxidation rates were similar to baseline. The transient postcardioplegic increase in substrate oxidation was associated with a 43% +/- 23% elevation of oxygen consumption (MVO2) compared with baseline and a 62% +/- 18% increase in myocardial blood flow. Cardiac output and mean arterial pressure did not change significantly after WCBCP, although myocardial function (stroke work, left ventricular end-systolic pressure, end-diastolic pressure, contractility, and efficiency) was depressed (p < 0.05). End-diastolic pressure and contractility improved from early to late phase of recovery, whereas the other indicators of ventricular function remained depressed.
  
  
  CONCLUSIONS
  Myocardial substrate oxidation was preserved after 3 hours of WCBCP, although ventricular function was moderately impaired. Thus, WCBCP with a seemingly normal substrate and oxygen supply was associated with a reduced cardiac efficiency.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Medical School, University of Tromsø, Norway. oddpe@fagmed.uit.no
authors.forename: O P
authors.initials: OP
authors.lastname: Elvenes
authors.forename: C
authors.initials: C
authors.lastname: Korvald
authors.forename: L M
authors.initials: LM
authors.lastname: Ytrebø
authors.forename: O
authors.initials: O
authors.lastname: Irtun
authors.forename: T
authors.initials: T
authors.lastname: Myrmel
authors.forename: T S
authors.initials: TS
authors.lastname: Larsen
authors.forename: D
authors.initials: D
authors.lastname: Sørlie
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001833:Body Temperature Regulation / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005260:Female; D006324:Heart Arrest, Induced; D006439:Hemodynamics / Q000502:physiology; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D010477:Perfusion; D013552:Swine; D016277:Ventricular Function, Left / Q000502:physiology
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified