Left ventricular diastolic suction with zero left atrial pressure
in the open-chest dog.
Ingels, Neil B., George T. Daughters, Srdjan D. Nikolic, Abe Deanda,
Marc R. Moon, Ann F. Bolger, Masashi Komeda, Geraldine C. Derby,
Edward L. Yellin, and D. Craig Miller.
Department of Cardiovascular Physiology and Biophysics, Research
Institute, Palo Alto Medical Foundation, Palo Alto, California 94301,
Department of Cardiovascular and Thoracic Surgery and Division of
Cardiovascular Medicine, Stanford University School of Medicine,
Stanford, California 94305, Cardiac Surgery and Cardiology Sections,
Department of Veterans Affairs Medical Center, Palo Alto, California
94304, and the Albert Einstein College of Medicine, Bronx, New York
10461
APStracts 2:0404H, 1995.
We investigated LV diastolic volume changes (suction inflows) with
left atrial pressure (LAP) clamped to ambient pressure in 6 open
-chest, anesthetized dogs. The left atrium was cannulated and
connected to a servo pump and LAP was clamped to a setpoint near 0
mmHg for 4 beats by withdrawing blood. Before the clamp, LAP averaged
5.88 1.44 mmHg and fell to 0.74 0.61 mmHg (p<0.0001) after the
clamp. During the first clamped beat a transmitral pressure gradient
of 1.0 0.6 mmHg was observed, resulting in LV filling of 2.6 1.8 ml.
Subsequent beats developed suction-driven (mean negative LVP: -1.5
+/- 1.3 mmHg; p<0.005 vs. zero) LV filling of 4.5 2.8 ml/beat
with a peak transmitral pressure gradient of 1.7 0.6 mmHg. These data
are consistent with an hypothesis that LV suction can be an important
filling mechanism under conditions where LV end-systolic volume is
reduced; e.g. reduced filling pressures, high heart rates, exercise,
or increased inotropic drive.
Received 3 April 1995; accepted in final form 15 August 1995.
APS Manuscript Number H314-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 September 1995.