The influence of the atrial myocardium on impulse formation in the rabbit sinus node

Charles J.H.J. Kirchhof, Felix I.M. Bonke, Maurits A. Allessie, Wim J.E.P. Lammers

Research output: Contribution to journalArticlepeer-review

66 Citations (Scopus)

Abstract

In the isolated right atrium of the rabbit heart the influence of the atrial myocardium on impulse formation in the sinus node was investigated. Under normal conditions the pacemaker (earliest activation) was located in the center of the node where fibers with the highest rate of diastolic depolarization were found. After disconnection of the atrium from the sinus node spontaneous cycle length decreased from a mean of 348 ms to a mean of 288 ms (-18%) in all experiments (n=15). This was accompanied by a shift of the pacemaker from the nodal center towards the border zone. By means of multiple microelectrode impalements changes in action potential configuration were studied. After disconnection of atrium and sinus node the rate of diastolic depolarization of fibers in the border zone was increased from a mean of 26 mV/s to a mean of 78 mV/s, whereas in the center of the sinus node no increase was found (mean: 52 mV/s). It was concluded that the fibers in the border zone of the sinus node are better pacemaker fibers than in the nodal center. However under normal conditions the intrinsic pacemaker properties of the border zone fibers are electronically depressed by the connected atrial myocardium.

Original languageEnglish
Pages (from-to)198-203
Number of pages6
JournalPflügers Archiv European Journal of Physiology
Volume410
Issue number1-2
DOIs
Publication statusPublished - Sep 1 1987

Keywords

  • Diastolic depolarization
  • Electrotonic influence
  • Impulse formation
  • Sinus arrhythmia
  • Sinus node

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)

Fingerprint

Dive into the research topics of 'The influence of the atrial myocardium on impulse formation in the rabbit sinus node'. Together they form a unique fingerprint.

Cite this