Chanege of significant first degree atroventricular block to normal PR interval during propofol anesthesia

초록

Propofol has known to have a direct concentration dependent inhibitory effect on the cardiac conduction systems (1). There are a few case reports describing conversion to normal sinus rhythm (NSR) after propofol injection in tachyarrhythmic patients (2). However, we found a case in which a patient's asymptomatic first degree atrioventricular (AV) block was changed to NSR While infusion of propofol. Whether the conversion was the result of a direct effect of propofol on AV nodal conduction cannot be determined. Nevertheless, we submit that non-fast HR and PR prolongation would be prone to depress negative dromotropic effect or enhance AV nodal conduction by frequency-dependent behavior of propofol resulting normalization of PR interval. In addition propofol anesthesia would reduce parasympathetic tone greater than sympathetic tone (3). In conclusion, this case suggested that propofol may have an effect on autonomic tone or AV nodal conduction.