Left ventricular diastolic suction with zero left atrial pressure in open-chest dogs.
We investigated left ventricular (LV) diastolic volume changes (suction inflows) with left atrial pressure (LAP) clamped to ambient pressure in six open-chest, anesthetized dogs. The left atrium was cannulated and connected to a servo pump, and LAP was clamped to a set point near 0 mmHg for four beats by withdrawing blood. LAP averaged 5.88 +/- 1.44 mmHg before the clamp 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 LV pressure: -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 the hypothesis that LV suction can be an important filling mechanism under condition in which LV end-systolic volume is reduced, e.g., reduced filling pressures, high heart rates, exercise, or increased inotropic drive.
Ingels
N B
NB
Department of Cardiovascular Physiology and Biophysics, Palo Alto Medical Foundation 94301, USA. (With the Technical Assistance of Cynthia E. Handen, Mary K. Zasio, and Erin M. Schultz.)
Daughters
G T
GT
Nikolic
S D
SD
DeAnda
A
A
Moon
M R
MR
Bolger
A F
AF
Komeda
M
M
Derby
G C
GC
Yellin
E L
EL
Miller
D C
DC
D000818:Animals; D016279:Atrial Function, Left; D001810:Blood Volume; D003326:Coronary Circulation; D003971:Diastole; D004285:Dogs; D005260:Female; D008297:Male; D011312:Pressure; D016277:Ventricular Function, Left