title: Esmolol before 80 min of cardiac arrest with oxygenated cold blood cardioplegia alleviates systolic dysfunction. An experimental study in pigs.
abstract: OBJECTIVE
  Myocardial dysfunction after reperfusion can be a clinical problem in the early postoperative phase after on-pump cardiac surgery. The aim was, in an experimental setting, to investigate if administration of the beta-adrenergic receptor blocker esmolol prior to cross-clamping for 80 min with cold oxygenated blood cardioplegia would improve myocardial protection and early postoperative function.
  
  
  METHODS
  Twenty-four anaesthetised pigs were randomly allocated into one of two equally sized groups and put on mild hypothermic cardiopulmonary bypass. Esmolol 1 mg kg(-1) or saline was administered into the arterial line 4 min prior to aortic cross-clamp. Cardiac arrest during 80 min of cross-clamp was obtained with repeated antegrade cold oxygenated blood cardioplegia; the pigs were weaned from bypass following a standardised protocol. Left ventricular global and regional myocardial function and tissue blood flow were evaluated with conductance catheter, echocardiography and coloured microspheres at baseline and at 1, 2 and 3 h after declamping. Four animals did not fulfil the protocol and were excluded.
  
  
  RESULTS
  No significant differences between groups could be demonstrated for left ventricular global and local function and tissue blood flow at baseline. At 1h after declamping the slope of preload recruitable stroke work (PRSW(slope)) averaged 73.7+/-12.7 mm Hg (SD) in controls and 72.7+/-11.1 mm Hg in esmolol-treated animals. In controls PRSW(slope) decreased to 62.1+/-11.0 and 58.4+/-12.7 mm Hg after 2 and 3h, respectively (p<0.005 vs 1h for both). In the esmolol-treated animals PRSW(slope) remained unchanged at 72.0+/-11.4 and 73.7+/-12.9 mm Hg at 2 and 3 h after declamp and were significantly higher (p<0.025 and <0.001) than the corresponding values in the control group. The slope of the end systolic pressure volume relationship did not differ between groups at 1 and 2 h after declamp, but were 1.85+/-0.86 and 2.51+/-0.96 mm Hg ml(-1) in controls and in esmolol-treated animals, respectively, after 3h (p<0.025).
  
  
  CONCLUSIONS
  Esmolol administered prior to cold oxygenated cardioplegic arrest alleviates left ventricular dysfunction in the early hours after cardiopulmonary bypass.
authors.affiliation: Department of Surgical Sciences, University of Bergen, Haukeland University Hospital, N-5021 Bergen, Norway. tfan@online.no
authors.forename: Tord
authors.initials: T
authors.lastname: Fannelop
authors.forename: Geir Olav
authors.initials: GO
authors.lastname: Dahle
authors.forename: Knut
authors.initials: K
authors.lastname: Matre
authors.forename: Christian Arvei
authors.initials: CA
authors.lastname: Moen
authors.forename: Arve
authors.initials: A
authors.lastname: Mongstad
authors.forename: Finn
authors.initials: F
authors.lastname: Eliassen
authors.forename: Leidulf
authors.initials: L
authors.lastname: Segadal
authors.forename: Ketil
authors.initials: K
authors.lastname: Grong
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage* / Q000494:pharmacology; D000818:Animals; D002315:Cardiopulmonary Bypass / Q000379:methods; D005260:Female; D006324:Heart Arrest, Induced / Q000379:methods*; D008297:Male; D023421:Models, Animal; D011412:Propanolamines / Q000008:administration & dosage* / Q000494:pharmacology; D011897:Random Allocation; D013552:Swine; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000188:drug therapy*
chemical_list: D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; C036604:esmolol