High-dose remifentanil suppresses sinoatrial conduction and sinus node automaticity in pediatric patients under...

We sought to determine the effect of remifentanil on sinus node function and the atrial-His (AH) interval in pediatric patients undergoing radiofrequency catheter ablation.

Sixty pediatric patients with Wolff-Parkinson-White syndrome were prospectively enrolled in this study. General anesthesia was induced and maintained with a continuous infusion of propofol. We recorded the calculated sinoatrial conduction time (CSACT), corrected sinus node recovery time (CSNRT), and AH interval when the patients were in a stable anesthetic state and compared the values before and during remifentanil administration at a moderate dose (0.2 μg · kg(-1) · min(-1)) or a high dose (0.4 μg · kg(-1) · min(-1)). Data are expressed as mean (95% confidence interval).

At the moderate dose, remifentanil prolonged CSNRT (from 177 [117-237] milliseconds to 245 [167-322] milliseconds after administration; P=0.016), but had no effect on either CSACT (P=0.59) or AH interval (P=0.11). However, high-dose remifentanil prolonged both CSNRT (from 201 [144-260] milliseconds to 307 [232-382] milliseconds after administration; P=0.019) and CSACT (from 48 [31-65] milliseconds to 78 [59-96] milliseconds after administration; P=0.038), but had no effect on the AH interval (P=0.058). The interaction in CSNRT between remifentanil administration and its dose was not different (P=0.44).

Remifentanil may inhibit both intraatrial conduction and sinus node automaticity, but it has no effect on conduction through the atrioventricular node. Dose dependency was not observed within the range of 0.2 to 0.4 μg · kg(-1) · min(-1) of remifentanil.