title: Cardiac changes during arousals from non-REM sleep in healthy volunteers.
abstract: Our aim was to evaluate cardiac changes evoked by spontaneous and sound-induced arousals from sleep. Cardiac responses to spontaneous and auditory-induced arousals were recorded during overnight sleep studies in 28 young healthy subjects (14 males, 14 females) during non-rapid eye movement sleep. Computerized analysis was applied to assess beat-to-beat changes in heart rate, atrio-ventricular conductance, and ventricular repolarization from 30 s before to 60 s after the auditory tone. During both types of arousals, the most consistent change was the increase in the heart rate (in 62% of spontaneous and in 89% of sound-induced arousals). This was accompanied by an increase or no change in PR interval and by a decrease or no change in QT interval. The magnitude of all cardiac changes was significantly higher for tone-induced vs. spontaneous arousals (mean +/- SD for heart rate: +9 +/- 8 vs. +13 +/- 9 beats per min; for PR prolongation: 14 +/- 16 vs. 24 +/- 22 ms; for QT shortening: -12 +/- 6 vs. -20 +/- 9 ms). The prevalence of transient tachycardia and PR prolongation was also significantly higher for tone-induced vs. spontaneous arousals (tachycardia: 85% vs. 57% of arousals, P < 0.001; PR prolongation: 51% vs. 25% of arousals, P < 0.001). All cardiac responses were short-lasting (10-15 s). We conclude that cardiac pacemaker region, conducting system, and ventricular myocardium may be under independent neural control. Prolongation of atrio-ventricular delay may serve to increase ventricular filling during arousal from sleep. Whether prolonged atrio-ventricular conductance associated with increased sympathetic outflow to the ventricular myocardium contributes to arrhythmogenesis during sudden arousal from sleep remains to be evaluated.
authors.affiliation: Department of Human Physiology, Flinders Medical Centre, Bedford Park, SA 5042, Australia. eugene.nalivaiko@flinders.edu.au
authors.forename: Eugene
authors.initials: E
authors.lastname: Nalivaiko
authors.forename: Peter G
authors.initials: PG
authors.lastname: Catcheside
authors.forename: Amanda
authors.initials: A
authors.lastname: Adams
authors.forename: Amy S
authors.initials: AS
authors.lastname: Jordan
authors.forename: Danny J
authors.initials: DJ
authors.lastname: Eckert
authors.forename: R Doug
authors.initials: RD
authors.lastname: McEvoy
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001143:Arousal / Q000502:physiology*; D001283:Atrioventricular Node / Q000502:physiology; D004562:Electrocardiography; D004576:Electromyography; D004585:Electrooculography; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D012890:Sleep / Q000502:physiology*; D012894:Sleep Stages / Q000502:physiology*; D013610:Tachycardia / Q000503:physiopathology; D013997:Time Factors