Electrophysiological effects of propofol on the normal cardiac conduction system.
To determine the electrophysiological effects of propofol and to explain the potential mechanism(s) whereby it causes bradyarrhythmias, 10 closed-chest pigs weighing 20-25 kg were studied. Each animal was premedicated by intramuscular administration of ketamine hydrochloride, intubated, and mechanically ventilated. Femoral arterial and venous catheters were placed, and a comprehensive electrophysiologic evaluation was performed at baseline and after two doses (1 mg/kg i.v. bolus and 0.1 mg/kg/min infusion and an extra 1- mg/kg i.v. bolus and 0.2 mg/kg/min infusion) of propofol. The electrophysiological effects obtained on low-and high-dose propofol were compared to baseline values. Propofol caused a dose-related decrease in sinus cycle length (baseline 565 +/- 36 ms, low-dose propofol 541 +/- 28, high-dose propofol 527 +/- 26 ms; p < 0.05), a prolongation of the corrected sinus node recovery time (baseline 119 +/- 35 ms, low-dose propofol 126 +/- 32, high-dose propofol 130 +/- 30 ms; p < 0.01), and an increase in the His-ventricular interval (baseline 33 +/- 4 ms, low-dose propofol 36 +/- 4, high-dose propofol 40 +/- 3 ms; p < 0.005). All other electrophysiological parameters remained unchanged, and there were no cases of spontaneous atrioventricular block or sinus pauses. We conclude that propofol causes dose-related depression of sinus node and His-Purkinje system functions, but has no effect on the atrioventricular node function and on the conduction properties of atrial and ventricular tissues in normal pig hearts.
Pires
L A
LA
Department of Medicine, University of Massachusetts Medical Center, Worcester 01655, USA.
Huang
S K
SK
Wagshal
A B
AB
Kulkarni
R S
RS
D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001919:Bradycardia / Q000139:chemically induced / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D004567:Electrodes, Implanted; D004594:Electrophysiology; D006329:Heart Conduction System / Q000187:drug effects* / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D015742:Propofol / Q000494:pharmacology*; D013552:Swine
D018686:Anesthetics, Intravenous; D015742:Propofol