Effect of anaesthesia on the cardiac response to intravenous adenosine.

Abstract

The cardiac response to intravenous adenosine 112 micrograms kg-1 was studied in 16 patients scheduled for coronary artery bypass surgery before and during anaesthesia with 1% end-tidal isoflurane and fentanyl 10 micrograms kg-1. Mean time from injection to onset of adenosine-induced PR prolongation was significantly greater during anaesthesia (12.8 (SD 5) vs 9.9 (3) s, P = 0.032). Atrioventricular block (assessed by the total number of non-conducted P waves) was significantly less during anaesthesia (12 vs 27, P = 0.016). We conclude that anaesthesia including 1% isoflurane and fentanyl 10 micrograms kg-1 delays the onset and reduces the magnitude of adenosine-induced atrioventricular block.