Atrioventricular conduction during adenosine-induced hypotension in dogs anaesthetized with sevoflurane.
We have studied the effects of adenosine-induced hypotension on A-H interval (atrioventricular (AV) nodal conduction time during sinus rhythm), St-H interval (intra-atrial plus AV nodal conduction time during atrial pacing), H-V interval (His-Purkinje conduction time) and H-S interval (total ventricular conduction time) by His-bundle electrocardiography in addition to surface electrocardiogram during both sinus rhythm and atrial pacing in nine dogs anaesthetized with 1 MAC of sevoflurane. Stepwise increases in infusion rates of adenosine to 0.1, 0.3, 0.5 and 1.0 mg kg-1 min-1 produced a dose-related decrease in mean arterial pressure from 91 (6) to 38 (2) mm Hg. Adenosine significantly increased the A-H interval at infusion rates of 0.5 mg kg-1 min-1 and above, and the St-H interval at 1.0 mg kg-1 min-1. The H-V and H-S intervals remained unchanged. Heart rate decreased significantly only at 1.0 mg kg-1 min-1 with a significant increase in the PR interval. Adenosine-induced hypotension did not have deleterious effects on AV conduction times and the surface electrocardiogram in dogs anaesthetized with 1 MAC of sevoflurane. This may indicate that the effects of adenosine on AV conduction were small and therefore are unlikely to be a contraindication to the use of adenosine for inducing hypotension in patients with initially normal conduction during sevoflurane anaesthesia.
Ishii
R
R
Department of Anaesthesiology, Ohmiya Red Cross Hospital, Tochigi, Japan.
Akazawa
S
S
Shimizu
R
R
Nakaigawa
Y
Y
Ikeno
S
S
Yamato
R
R
D000241:Adenosine / Q000494:pharmacology*; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D001283:Atrioventricular Node / Q000187:drug effects*; D004285:Dogs; D004347:Drug Interactions; D004562:Electrocardiography / Q000187:drug effects; D004594:Electrophysiology; D004987:Ethers / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects; D007023:Hypotension, Controlled / Q000379:methods*; D008738:Methyl Ethers; D000077149:Sevoflurane; D014665:Vasodilator Agents / Q000494:pharmacology*
D018685:Anesthetics, Inhalation; D004987:Ethers; D008738:Methyl Ethers; D014665:Vasodilator Agents; D000077149:Sevoflurane; D000241:Adenosine