Does the sympathetic nervous system influence sinus arrhythmia in man? Evidence from combined autonomic blockade

J Physiol. 1984 Nov;356:459-64. doi: 10.1113/jphysiol.1984.sp015476.


The influences of vagal and sympathetic efferent activity on sinus arrhythmia in man have been studied in healthy subjects by administration of hyoscine butylbromide and atenolol alone and combined using a microcomputer-linked electrocardiogram (e.c.g.) system. Sinus arrhythmia was quantitated as the S.D. of the R-R interval. Sinus arrhythmia was reduced by hyoscine butylbromide, in some subjects to near abolition, but this end-point was unchanged by pre-treatment with atenolol. Atenolol alone prolonged the mean R-R interval and increased sinus arrhythmia. It is suggested that sinus arrhythmia in man is mediated through vagal efferents alone but that atenolol increases the arrhythmia through a central vagotonic effect.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Arrhythmia, Sinus / chemically induced
  • Arrhythmia, Sinus / physiopathology*
  • Atenolol / pharmacology
  • Autonomic Nerve Block*
  • Butylscopolammonium Bromide / pharmacology
  • Efferent Pathways / physiopathology
  • Electrocardiography
  • Female
  • Humans
  • Male
  • Sympathetic Nervous System / drug effects
  • Sympathetic Nervous System / physiopathology*


  • Butylscopolammonium Bromide
  • Atenolol