A. Ylihankala et al., ATROPINE ABOLISHES ELECTROENCEPHALOGRAM-ASSOCIATED HEART-RATE CHANGESWITHOUT AN EFFECT ON RESPIRATORY SINUS ARRHYTHMIA DURING ANESTHESIA IN HUMANS, Acta Physiologica Scandinavica, 149(4), 1993, pp. 435-440
Heart rate fluctuates with the electroencephalogram burst suppression
pattern during anaesthesia: increasing at burst onset and decreasing a
t suppression. Heart rate also oscillates with positive pressure venti
lation. The effects of atropine on these heart rate changes were studi
ed in 12 patients during isoflurane anaesthesia and positive pressure
ventilation at a frequency of 6 cycles min(-1). Four additional patien
ts served as controls. A bolus dose of atropine (20 mu g kg(-1) intrav
enously) abolished the electroencephalogram-correlated heart rate chan
ges; however, the amplitude of respiratory sinus arrhythmia was not ch
anged after atropine. The control mechanism of the burst suppression p
attern in electroencephalogram also affects parasympathetic heart rate
control. The control mechanisms of respiratory sinus arrhythmia durin
g anaesthesia with positive pressure ventilation differ from those dur
ing spontaneous breathing awake.