Floppy interatrial septum mimicking an
            ASD
            : The role of left atrial pressure

To study the functional role of the atriorenal reflex in the nonhuman primate, we chronically instrumented six Macaca fascicularis with left atrial snares and left atrial and aortic catheters. After inserting a bladder catheter, we determined hemodynamic and renal responses of the conscious chair-restrained monkey to increased left atrial pressure. In 23 snare experiments, no significant changes in renal or cardiovascular function were observed even though left atrial pressure increased from 6.5 +/- 3.3 to 16.2 +/- 3.4 mmHg. The animals were subjected also to blood volume expansion with isoncotic isotonic dextran solutions (+15% of calculated blood volume). They responded normally to this volume stimulus. Conscious dogs prepared in the same manner as the nonhuman primate exhibited diuresis in response to elevations of atrial pressure. We conclude that left atrial stretch receptors are not importantly involved in volume homeostasis in the nonhuman primate.

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The important role of left ventricular relaxation and left atrial pressure in the left ventricular filling velocity profile

American Heart Journal ◽

10.1016/0002-8703(89)90230-5 ◽

1989 ◽

Vol 118 (5) ◽

pp. 954-962 ◽

Cited By ~ 33

Author(s):

Shigehito Takagi ◽

Mitsuhiro Yokota ◽

Masatsugu Iwase ◽

Junshi Yoshida ◽

Hiroshi Hayashi ◽

...

Keyword(s):

Velocity Profile ◽

Left Atrial ◽

Left Ventricular ◽

Left Ventricular Filling ◽

Atrial Pressure ◽

Left Atrial Pressure ◽

Left Ventricular Relaxation ◽

Ventricular Relaxation ◽

Ventricular Filling

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Role of the papillary muscle in opening and closure of the mitral valve

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1980.238.3.h348 ◽

1980 ◽

Vol 238 (3) ◽

pp. H348-H354 ◽

Cited By ~ 4

Author(s):

M. Marzilli ◽

H. N. Sabbah ◽

T. Lee ◽

P. D. Stein

Keyword(s):

Mitral Valve ◽

Papillary Muscle ◽

Left Atrial ◽

Left Ventricular ◽

Atrial Pressure ◽

Left Atrial Pressure ◽

Dimensional Changes ◽

Opening And Closing ◽

Isovolumic Relaxation

Dimensional changes of the left ventricular anterolateral papillary muscle of six open-chest dogs were measured continuously throughout the cardiac cycle in order to evaluate the role of the papillary muscle in opening and closing of the mitral valve. Dimensional changes were measured with ultrasonic dimension gauges. Maximal shortening and maximal elongation of the papillary muscle followed maximal shortening and elongation of a segment of the free wall of the left ventricle by 65 +/- 6 (SE) ms. Maximal elongation of the papillary muscle occurred 25 +/- 2 ms after the onset of ejection. Maximal shortening of the papillary muscle occurred 68 +/- 5 ms after the aortic incisura and 10 +/- 2 ms after the crossover of left ventricular and left atrial pressure. The papillary muscle shortened 14 +/- 4%. The percentage of papillary muscle shortening that occurred after the aortic incisura was 39 +/- 7%, and the percentage of shortening that occurred after the crossover of left ventricular and left atrial pressure was 3 +/- 1%. The observed shortening of the papillary muscle throughout left ventricular isovolumic relaxation suggests that the papillary muscle may have a role in opening the mitral valve. Conversely, elongation of the papillary muscle in the late portion of diastole appears necessary to permit proper closure of the mitral valve leaflets.

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