CHANGES IN HUMAN CORONARY SINUS BLOOD-FLOW AND MYOCARDIAL-METABOLISM INDUCED BY VENTRICULAR-FIBRILLATION AND DEFIBRILLATION

Background: During implantation of cardioverter-defibrillators,repeate d inductions of ventricular fibrillation and defibrillation are perfor med. Little is known about the myocardial metabolism associated with v entricular fibrillation and defibrillation in humans. Methods:Sixteen patients scheduled for transvenous cardioverter-defibrillator implanta tion were included in the study. In 10 of the patients, blood samples were taken simultaneously in the coronary sinus and radial artery and analyzed for PO2, PCO2, standard bicarbonate, pH, lactate, alanine, gl ucose, and glycerol. Oxygen saturation, base excess, and oxygen conten t were calculated. The patients were studied before, shortly after, an d 2 and 5 minutes after successful defibrillation. In six of the patie nts, coronary sinus blood flow was registered continuously. Results: T he coronary sinus blood flow declined from a basal value of 93 +/- 16 mL/min to 35 +/- 6 mL/min 14 +/- 2 seconds after induction of ventricu lar fibrillation. Following termination of ventricular fibrillation, c oronary sinus blood flow increased to a peak value of 227 +/- 75 mL/mi n. Oxygen saturation, PO2, and oxygen content in the coronary sinus in creased by approximately 25% shortly after each episode of ventricular fibrillation and defibrillation. The coronary sinus lactate increased and the arterio-coronary sinus lactate difference decreased shortly a fter each of the four episodes, but was normalized within 2 minutes. C onclusions: Repeated threshold tests during defibrillator implantation did not cause any long-lasting or cumulative metabolic effects, indic ating that the described technique, with a 5-minute recovery period in between episodes, is safe as regards myocardial metabolism. Copyright (C) 1998 by W.B. Saunders Company.