Short-acting beta-adrenergic antagonist esmolol given at reperfusion improves survival after prolonged ventricular fibrillation.
BACKGROUND
High catecholamine concentrations are cytotoxic to cardiac myocytes. We hypothesized that myocardial interstitial catecholamine levels are greatly elevated immediately after long-duration ventricular fibrillation (VF), defibrillation, and reperfusion and that the short-acting beta-antagonist esmolol administered at reperfusion would protect against this catecholamine surge and improve survival.


RESULTS
In part 1 of this study, catecholamines from myocardial interstitial fluid (ISF) and aortic and coronary sinus plasma were quantified by use of 3H-labeled radioenzymatic assay in 8 open-chest, anesthetized pigs. Eight minutes of electrically induced VF was followed by internal defibrillation and reperfusion. By 4 minutes of VF, ISF norepinephrine increased significantly, from 1.3+/-0.3 to 7.4+/-2.4 ng/mL. Epinephrine increased significantly, from 0.4+/-0.2 to 1.5+/-0.7 ng/mL. ISF norepinephrine and epinephrine peaked at 219.2+/-92.1 and 63.7+/-25.1 ng/mL after defibrillation and reperfusion and decreased significantly to 12.2+/-3.5 and 6.7+/-3.1 ng/mL 23 minutes after defibrillation. Transcardiac catecholamine changes were similar. In part 2, 8 minutes of VF was followed by external defibrillation in anesthetized, closed-chest pigs. Animals received 1.0 mg/kg esmolol (n=8) or saline (n=8) intravenously at the start of cardiopulmonary resuscitation (CPR). Advanced cardiac life support, including CPR and epinephrine, was delivered to both groups. Esmolol before reperfusion improved return of spontaneous circulation and 4-hour survival (7/8 versus 3/8 survivors, chi2 P<0.05).


CONCLUSIONS
Transcardiac and ISF norepinephrine and epinephrine levels are briefly massively elevated after 8 minutes of VF, defibrillation, and reperfusion. A short-acting beta-antagonist administered immediately after defibrillation improves return of spontaneous circulation and 4-hour survival after this prolonged VF.
Killingsworth
Cheryl R
CR
Cardiac Rhythm Management Laboratory, Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, AL 35294-0019, USA. crk@crml.uab.edu
Wei
Chih-Chang
CC
Dell'Italia
Louis J
LJ
Ardell
Jeffrey L
JL
Kingsley
Melody A
MA
Smith
William M
WM
Ideker
Raymond E
RE
Walcott
Gregory P
GP
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000818:Animals; D003131:Combined Modality Therapy; D004554:Electric Countershock; D004837:Epinephrine / Q000097:blood / Q000378:metabolism; D045604:Extracellular Fluid / Q000378:metabolism; D006352:Heart Ventricles / Q000378:metabolism; D007700:Kinetics; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000378:metabolism; D009638:Norepinephrine / Q000097:blood / Q000378:metabolism; D011412:Propanolamines / Q000627:therapeutic use*; D016019:Survival Analysis; D013552:Swine; D014693:Ventricular Fibrillation / Q000188:drug therapy / Q000378:metabolism / Q000628:therapy*; D016277:Ventricular Function, Left
D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; C036604:esmolol; D009638:Norepinephrine; D004837:Epinephrine