title: The pattern of activation of the sympathetic nervous system during tilt-induced syncope.
abstract: A 49-year-old patient with a history of situational syncope and minimal electrocardiographic signs of accessory pathway is described. The evidence for pre-excitation was present only during the sympathetic activation caused by exercise testing and isoprenaline infusion. This phenomenon served as an indicator of significant adrenergic drive to the heart after the tilt-induced syncope. The meaning of the observed electrocardiographic changes in the course of neurocardiogenic reaction and its contribution to the understanding of the sympatho-vagal balance during vasovagal syncope is discussed. The lack of preexcitation signs during syncope and its appearance several seconds after the syncope-related sinus pause indicates sympathetic withdrawal before and shortly after the asystole. The possible pathophysiological mechanisms are discussed.
authors.affiliation: Teaching Department for Emergency Medical Service, Medical University of Wroclaw, Bartla Street 5, 51-618 Wrocław, Poland. dzysko@wp.pl
authors.forename: Dorota
authors.initials: D
authors.lastname: Zyśko
authors.forename: Jacek
authors.initials: J
authors.lastname: Gajek
authors.forename: Ryszard
authors.initials: R
authors.lastname: Sciborski
authors.forename: Jacek
authors.initials: J
authors.lastname: Smereka
authors.forename: Igor
authors.initials: I
authors.lastname: Checiński
authors.forename: Walentyna
authors.initials: W
authors.lastname: Mazurek
mesh_terms: D000328:Adult; D006801:Humans; D008297:Male; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D013575:Syncope / Q000175:diagnosis* / Q000503:physiopathology*; D013610:Tachycardia / Q000175:diagnosis* / Q000503:physiopathology*; D018667:Tilt-Table Test / Q000379:methods*