Spatial and temporal variations in pacemaking and conduction in the
isolated renal pelvis.
Lammers, Wim J. E. P., H. R. Ahmad, and Kholoud Arafat.
Department of Physiology, Faculty of Medicine and Health Sciences,
United Arab Emirates University, Al Ain, United Arab Emirates and the
Department of Physiology, Faculty of Health Sciences, The Aga Khan
University, Karachi, Pakistan
APStracts 2:0181F, 1995.
In renal pelvis preparations isolated from the sheep, the location of
the pacemaker and the pathway of conduction of the electrical impulse
in the pelvis was analyzed in detail. An electrophysiological
acquisition system was used allowing simultaneous recordings from 240
extracellular electrodes. Reconstruction of the spread of activity
showed that the site of the pelvis pacemaker was in virtually all
cases located at the pelvicalyceal border, and never in the body of
the pelvis nor in the area of the pelviureteric junction. One single
pacemaker was responsible for a particular spread of activation and
fusion of activity originating from two or more pacemakers did not
take place. Furthermore, spontaneous shifts of the pacemaker could
occur from one site to another along the pelvicalyceal border.
Conduction from the site of the current pacemaker to the
pelviureteric junction and the ureter was slow, inhomogeneous and
contorted. Multiple instances of partial or total conduction block
were seen at all levels in the pelvis and were not restricted to the
pelviureteric junction. The occurrence of conduction block did not
seem to be related to the length of the preceding interval, implying
that the refractory period did not play a major role in the genesis
of intrapelvic conduction block. In conclusion, high resolution
mapping of the renal pelvis is possible and reveals location and
behavior of the pacemaker and documents inhomogeneities in conduction
and conduction block.
Received 15 June 1995; accepted in final form 25 September 1995.
APS Manuscript Number F193-5.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95