Prevention by dexamethasone of the marked antiarrhythmic effects of preconditioning induced 20 h after rapid cardiac pacing.
Dogs were paced, via a pacing electrode in the right ventricle, for four 5 min periods at a rate of 220 beats min-1. On the following day they were reanaesthetized, thoracotomized and the left anterior descending coronary artery occluded for 25 min. Pacing markedly reduced the severity of ischaemia-induced arrhythmias (e.g. reduction in VF from 45% in unpaced dogs to 10% in paced dogs; P < 0.05), an effect reversed by dexamethasone (4 mg kg-1 i.v., 45 min prior to pacing). This protection may be due to the induction of nitric oxide synthase or cyclo-oxygenase.
Vegh
A
A
Department of Pharmacology, Szent György Medical University, Szeged, Hungary.
Papp
J G
JG
Parratt
J R
JR
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial; D003331:Coronary Vessels / Q000502:physiology; D003907:Dexamethasone / Q000494:pharmacology*; D004285:Dogs; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D008297:Male
D003907:Dexamethasone