Diastolic time: an important determinant of regional arterial blood
flow.
Saupe, Kurt W., Curtis A. Smith, Kathleen S. Henderson, and Jerome A.
Dempsey.
John Rankin Laboratory of Pulmonary Medicine, Departments of
Physiology and Preventive Medicine, University of Wisconsin, Madison,
Wisconsin, 53705, USA
APStracts 2:0166H, 1995.
In unanesthetized dogs we measured heart rate, blood pressure and
external iliac, celiac and renal artery flows on a beat-by-beat
basis. All three flow fluctuated in synchrony with breathing. While
the fluctuations in renal flow could to a large degree be explained
by fluctuations in blood pressure, this was not the case in the
external iliac artery where flow increased when pressure decreased
and decreased when pressure increased. These paradoxical fluctuations
in flow appear to be caused by respiratory fluctuations in heart rate
as we observed a strong (r=.89) correlation between external iliac
flow and the length of the preceding diastole. Single long diastolic
periods, induced by atropine, were always followed by a beat of
increased flow even though arterial pressure was constant. We
conclude that diastolic time has a profound impact on blood flow
during the next beat. Our data support a model of the arterial system
where backpressure to flow through a bed is dependent on the amount
of time for diastolic runoff into the capillaries.
Received 24 September 1993; accepted in final form 17 March 1995.
APS Manuscript Number H848-3.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 2 May 1995.