FREQUENCY AND PROGNOSTIC IMPLICATIONS OF ELEVATED LEFT ATRIAL PRESSURE IN THE PRESENCE OF NORMAL RIGHT ATRIAL PRESSURE IN HEMODIALYSIS PATIENTS: RESULTS FROM A PROSPECTIVE COHORT OF 442 PATIENTS

Pericardiophrenic attachments transmit diaphragm contraction to the pericardium. We investigated this in two ways. 1) We replaced the hearts of externally perfused dogs with a balloon from which we measured pressure changes. Diaphragm contraction increased pressure from 4.6 to 5.5 Torr, equivalent to an isobaric volume decrease of 1.5%, and decreased volumetric compliance by 3%. 2) We selectively servo controlled right atrial pressure, left atrial pressure, or cardiac output in open-chest dogs and monitored the effect of diaphragm contraction on cardiovascular and abdominal pressures, cardiac output, and the volume of blood added to or withdrawn from the circulation to achieve servo control. Diaphragm contraction decreased left atrial pressure 0.4 Torr when right atrial pressure was controlled and right atrial pressure increased 0.2 Torr while controlling left atrial pressure, but there were no significant changes in cardiac output. Atrial pressure did not change significantly when output was controlled. Servo control required removal of approximately 50 ml of blood, presumably reflecting a decreased splanchnic vascular capacity at the higher abdominal pressure. We conclude that the diaphragm may slightly tense the pericardium, but this has no important primary effect on the heart.

Download Full-text

Development of a circulatory mock loop for biventricular device testing with various heart conditions

The International Journal of Artificial Organs ◽

10.1177/0391398820903316 ◽

2020 ◽

Vol 43 (9) ◽

pp. 600-605 ◽

Cited By ~ 1

Author(s):

Yuichiro Kado ◽

Takuma Miyamoto ◽

David J Horvath ◽

Shengqiang Gao ◽

Kiyotaka Fukamachi ◽

...

Keyword(s):

Heart Failure ◽

Pulmonary Artery ◽

Pulmonary Artery Pressure ◽

Left Atrial ◽

Aortic Pressure ◽

Atrial Pressure ◽

Left Atrial Pressure ◽

Right Atrial ◽

Right Atrial Pressure ◽

Artery Pressure

This study aimed to evaluate a newly designed circulatory mock loop intended to model cardiac and circulatory hemodynamics for mechanical circulatory support device testing. The mock loop was built with dedicated ports suitable for attaching assist devices in various configurations. This biventricular mock loop uses two pneumatic pumps (Abiomed AB5000™, Danvers, MA, USA) driven by a dual-output driver (Thoratec Model 2600, Pleasanton, CA, USA). The drive pressures can be individually modified to simulate a healthy heart and left and/or right heart failure conditions, and variable compliance and fluid volume allow for additional customization. The loop output for a healthy heart was tested at 4.2 L/min with left and right atrial pressures of 1 and 5 mm Hg, respectively; a mean aortic pressure of 93 mm Hg; and pulmonary artery pressure of 17 mm Hg. Under conditions of left heart failure, these values were reduced to 2.1 L/min output, left atrial pressure = 28 mm Hg, right atrial pressure = 3 mm Hg, aortic pressure = 58 mm Hg, and pulmonary artery pressure = 35 mm Hg. Right heart failure resulted in the reverse balance: left atrial pressure = 0 mm Hg, right atrial pressure = 30 mm Hg, aortic pressure = 100 mm Hg, and pulmonary artery pressure = 13 mm Hg with a flow of 3.9 L/min. For biventricular heart failure, flow was decreased to 1.6 L/min, left atrial pressure = 13 mm Hg, right atrial pressure = 13 mm Hg, aortic pressure = 52 mm Hg, and pulmonary artery pressure = 18 mm Hg. This mock loop could become a reliable bench tool to simulate a range of heart failure conditions.

Download Full-text

Atrial dynamics, atrial natriuretic factor, tachycardia, and blood volume in anesthetized rabbits

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1991.261.1.h22 ◽

1991 ◽

Vol 261 (1) ◽

pp. H22-H28 ◽

Cited By ~ 1

Author(s):

K. A. King ◽

J. R. Ledsome

Keyword(s):

Blood Volume ◽

Atrial Natriuretic Factor ◽

Left Atrial ◽

Wall Stress ◽

Atrial Pressure ◽

Right Atrial ◽

Right Atrial Pressure ◽

Atrial Wall ◽

Natriuretic Factor ◽

Atrial Natriuretic

The effects of tachycardia and a slow (1%/min) 20% reduction and elevation of blood volume (BV) on right atrial pressure (RAP), right atrial dimension (RAD), and plasma immunoreactive atrial natriuretic factor (IR-ANF) were examined in anesthetized rabbits. Plasma IR-ANF was significantly increased during pacing at 6 Hz in the presence of high BV but not at low BV. Mean RAP increased with expansion of BV, but this change was not associated with significant changes in IR-ANF. There were no statistically significant changes in systolic or diastolic RAD with alterations in BV or with tachycardia. Tachycardia had no effect on left atrial dimension. Diastolic right atrial wall stress (DRAS) and minute DRAS increased with a 20% increase in BV, but changes in BV did not affect systolic right atrial wall stress (SRAS) or minute SRAS. Tachycardia decreased DRAS at high BV and significantly increased SRAS and minute SRAS. The increases in SRAS and minute SRAS were greater during tachycardia at high BV, suggesting that an interaction between BV and tachycardia results in potentiation of SRAS and minute SRAS. The results suggest that systolic RAS is a significant factor in ANF release during tachycardia at high BV.

Download Full-text

Reference sites not influenced by hydrostatic pressure for right and left atrial pressures

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1964.207.2.357 ◽

1964 ◽

Vol 207 (2) ◽

pp. 357-360 ◽

Cited By ~ 1

Author(s):

George G. Armstrong ◽

John C. Hancock

Keyword(s):

Hydrostatic Pressure ◽

Reference Point ◽

Left Atrial ◽

Atrial Pressure ◽

Left Atrial Pressure ◽

Right Atrial ◽

Lateral Border ◽

Zero Reference ◽

The Right ◽

Made In

Simultaneous recordings of left and right atrial pressures made in dogs being rotated into all positions in space allowed the location of rotational axes where right or left atrial pressure became independent of hydrostatic pressure. Utilization of these axes as zero reference levels made possible the measurement of right or left atrial pressure without the influence of hydrostatic factors. The right zero reference point lay 62.8% of the distance from the manubrium to the xiphoid, 61.2% of the posterior to anterior thoracic diameter, and 47.7% of the greatest transverse thoracic diameter as measured from the right lateral border. The left atrial zero reference point lay 62.1% of the manubrium to xiphoid distance, 57.2% of the posterior to anterior diameter of thorax, and 53.0% of the greatest transverse thoracic diameter as measured from the right lateral border. When referred to the anatomy of the dog, these points lay in the immediate vicinity of the right and left atrioventricular valves, respectively.

Download Full-text

PEEP DOES NOT AFFECT LEFT ATRIAL - RIGHT ATRIAL PRESSURE GRADIENT IN NEUROSURGICAL PATIENTS

Anesthesiology ◽

10.1097/00000542-198609001-00303 ◽

1986 ◽

Vol 65 (Supplement 3A) ◽

pp. A305 ◽

Cited By ~ 3

Author(s):

Zasslow ◽

Pearl ◽

Larson ◽

Silverberg

Keyword(s):

Pressure Gradient ◽

Left Atrial ◽

Atrial Pressure ◽

Right Atrial ◽

Right Atrial Pressure ◽

Neurosurgical Patients

Download Full-text

Elevated cardiac pressure inhibits renin release after arterial hypotension in conscious dogs

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1984.247.6.r953 ◽

1984 ◽

Vol 247 (6) ◽

pp. R953-R959 ◽

Cited By ~ 1

Author(s):

M. E. Lee ◽

T. N. Thrasher ◽

D. J. Ramsay

Keyword(s):

Left Atrial ◽

Dose Range ◽

Plasma Renin ◽

Ascending Aorta ◽

Atrial Pressure ◽

Left Atrial Pressure ◽

Renin Release ◽

Right Atrial ◽

Apparent Paradox ◽

Systemic Hypotension

The relative roles of cardiopulmonary, sinoaortic, and renal baroreceptors in the regulation of plasma renin activity (PRA) were evaluated in dogs with chronically implanted cuffs around the ascending aorta proximal to the brachiocephalic artery, the abdominal aorta just proximal to both renal arteries, or both. Inflation of either cuff was adjusted to cause a reduction of distal arterial pressure and hence renal perfusion pressure (RPP) of 0, 5, 10, 20, or 30% of control for 1 h. Reduction of RPP by inflation of the suprarenal cuff (n = 4) led to a significant (P less than 0.05) increase in PRA throughout the dose range examined. However, constriction of the ascending aorta (n = 7) to cause identical reductions in RPP failed to increase PRA. The apparent paradox in these results may be explained by differential effects of the two maneuvers on left atrial pressure. Left atrial pressure increased dose dependently during inflation of the ascending aortic cuff but did not change during inflation of the suprarenal cuff. To determine if elevated right atrial pressure (RAP) would inhibit renin release after systemic hypotension, another group of dogs (n = 4) was prepared with cuffs around the pulmonary artery. Inflation of the pulmonary cuff to cause similar systemic hypotension led to significant (P less than 0.05) increases in PRA and RAP. Therefore we conclude that powerful inhibitory signals, arising from the left heart, can inhibit renin release in response to systemic hypotension.

Download Full-text

Cardiovascular effects of increasing airway pressure in the dog

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1977.232.1.h35 ◽

1977 ◽

Vol 232 (1) ◽

pp. H35-H43 ◽

Cited By ~ 6

Author(s):

S. M. Scharf ◽

P. Caldini ◽

R. H. Ingram

Keyword(s):

Lung Volume ◽

Airway Pressure ◽

Left Atrial ◽

Venous Return ◽

Pressure Rise ◽

Cardiovascular Effects ◽

Atrial Pressure ◽

Pleural Pressure ◽

Left Atrial Pressure ◽

Right Atrial

In paralyzed anesthetized dogs the cardiovascular effects of increasing positive end-expiratory pressure (PEEP) were explored under two conditions: a) end-expiratory lung volume increasing, b) end-expiratory lung volume kept nearly constant by matching pleural pressure rise to end-expiratory airway pressure rise. Two series of experiments were done: I) xenous return was allowed to fall, II) venous return was kept constant by infusion of volume. Right atrial pressure, pulmonary arterial pressure, and left atrial pressure increased under all conditions when measured relative to atmospheric pressure, but increased relative to pleural pressure only under condition a. The rise in left atrial relative to pleural pressure may indicate a degree of left ventricular dysfunction associated with increasing end-expiratory lung volume. Furthermore, when end-expiratory lung volume increased, inequality of the rise in pulmonary artery wedge pressure exceeded the rise in left atrial pressure in series I. From plots of cardiac output as a function of right atrial pressure it was possible to conclude that the decrease in venous return is partially offset by an increase in mean circulatory pressure.

Download Full-text

Action of Digitalis on the Nonfailing Heart of the Dog

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1957.192.1.114 ◽

1957 ◽

Vol 192 (1) ◽

pp. 114-120 ◽

Cited By ~ 76

Author(s):

Marion deV. Cotten ◽

Phyllis E. Stopp

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Left Atrial ◽

Venous Return ◽

Contractile Force ◽

Left Ventricular ◽

Atrial Pressure ◽

Left Atrial Pressure ◽

Right Atrial ◽

Stroke Work

Ouabain induces a moderate increase in the contractility of the nonfailing heart of the dog with a complete circulatory system in doses which do not produce electrocardiographic signs of digitalis intoxication. The increased contractility was demonstrated both by the increase in ventricular contractile force and by the higher ventricular function curves obtained after administration of ouabain. The drug also increased systemic peripheral resistance and blood pressure, decreased systemic output, heart rate, left and right atrial pressures, and produced only small, variable changes in left ventricular stroke work. The reduction in systemic output and left atrial pressure and the absence of substantial changes in stroke work after ouabain appeared to be the result of a decrease in venous return to the heart. Evidence for this interpretation was obtained from experiments in which left atrial pressure was kept constant during the actions of ouabain by infusing 100–300 cc of whole blood. Under these conditions, ouabain brought about moderate increases in systemic output and left ventricular stroke work as well as in contractile force even though the changes in heart rate and blood pressure were comparable to those obtained in experiments in which left atrial pressure was uncontrolled. The data presented indicate that ouabain has two primary hemodynamic effects in the normal animal, namely, a direct cardiac stimulant action and a peripheral action resulting in a decreased venous return. The relationship of these findings to the mechanism of action of digitalis in congestive heart failure is discussed.

Download Full-text