Incidence of arrhythmias and heart rate variability in wild-type rats exposed to social stress

A. Sgoifo*, S.F. de Boer, C. Westenbroek, Frans W. Maes, H. Beldhuis, Takanori Suzuki, J.M. Koolhaas

*Corresponding author for this work

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Psychological stressors of different natures can induce different shies of autonomic control on cardiac electrical activity, with either a sympathetic or a parasympathetic prevalence. Arrhythmia occurrence, R-R interval variability, and plasma catecholamine elevations were measured in male wild-type rats exposed to either a social stressor (defeat) or a nonsocial challenge (restraint). Electrocardiograms were telemetrically recorded, and blood samples were withdrawn through jugular vein catheters from normal, freely moving animals. Defeat produced a much higher incidence of arrhythmias (mostly ventricular premature beats), which were mainly observed in the 60-s time periods after attacks. The social challenge also induced a much stronger reduction of average R-R interval, a lower R-R interval variability (as estimated by the time-domain parameters standard deviation of mean R-R interval duration, coefficient of variance, and root mean square of successive differences in R-R interval duration), and higher elevations of venous plasma catecholamines compared with restraint. These autonomic and/or neuroendocrine data indicate that a social stressor such as defeat is characterized by both a higher sympathetic activation and a lower parasympathetic antagonism compared with a nonsocial restraint challenge, which results in a higher risk for ventricular arrhythmias.

Original languageEnglish
Pages (from-to)H1754-H1760
Number of pages7
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number4
Publication statusPublished - Oct-1997


  • telemetry electrocardiogram
  • autonomic nervous system
  • catecholamines
  • defeat
  • restraint

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