A Theoretical Right Atrial Pressure Feedback Heart Rate Control System to Restore Physiologic Control to the Rate-limited Heart

To investigate the relationship between right atrial pressure (RAP) and atrial natriuretic peptide (ANP) release during prolonged exercise in a hot environment (30 degrees C, 20% relative humidity), we studied with a Swan-Ganz catheter five male volunteers exercising on a cycle ergometer at 60% of peak aerobic power for 50 min. The ANP level increased from 14 +/- 3 (SE) to 69 +/- 10 pg/ml (P < 0.001) during the first 10 min of exercise as RAP rose from 4.3 +/- 0.8 to 6.9 +/- 1.1 mmHg (P < 0.001). The 10-min ANP level was significantly correlated with RAP (r = 0.88, P < 0.05) but not with heart rate, pulmonary arterial blood temperature, plasma norepinephrine, or plasma epinephrine. The 10-min RAP value was inversely correlated with blood volume (r = -0.98, P < 0.01) and also with stroke volume (r = -0.96, P < 0.01). In the next 20 min of exercise, ANP continued to increase to 101 +/- 12 pg/ml (P < 0.02 vs. 10 min) and remained at this level until 50 min of exercise, whereas RAP decreased and reached a level not significantly different from baseline at 50 min (5.7 +/- 1.0 mmHg; P < 0.01 vs. 10 min). This dissociation of ANP and RAP may have been related to the significant increases from the 10-min values of heart rate, blood temperature, norepinephrine (all P < 0.01), and epinephrine (P < 0.02) during the same period. These results suggest that ANP release is primarily controlled by atrial distension at the onset of exercise but that other stimulators may be involved thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)

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Cardiovascular function and norepinephrine-thermogenesis in cold-acclimatized rats

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1963.204.5.888 ◽

1963 ◽

Vol 204 (5) ◽

pp. 888-894 ◽

Cited By ~ 30

Author(s):

Eugene Evonuk ◽

John P. Hannon

Keyword(s):

Heart Rate ◽

Cardiac Output ◽

Arterial Pressure ◽

Stroke Volume ◽

Room Temperature ◽

Metabolic Response ◽

Atrial Pressure ◽

Right Atrial ◽

Right Atrial Pressure ◽

Systemic Resistance

The cardiovascular and metabolic actions of norepinephrine (NE) and their inter-relationships were studied at normal room temperature in anesthetized, warm-acclimatized (W-A) (26 ± 1 C) and cold-acclimatized (C-A) (3 ± 1 C) rats. The cardiac output, heart rate, stroke volume, arterial pressure, right atrial pressure, and systemic resistance were measured prior to NE infusion; during NE infusion (2 µg/min) at the 25, 50, 75, and 100% levels of increased metabolism; and after infusion of NE had ceased. Norepinephrine caused a greater increase in the cardiac output, heart rate, stroke volume, and right atrial pressure in the C-A animals than it did in W-A animals. During the early metabolic response to NE (i.e., up to 25% increase in O2 consumption) there was a marked increase in the arterial pressure of both W-A and C-A rats, with the latter showing the greater maximum response. Beyond the 25% level of increased metabolism the arterial pressure and concomitantly the systemic resistance of the C-A animals declined sharply to the preinfusion levels where they remained throughout the course of infusion. In contrast to this, the arterial pressure and systemic resistance of the W-A animals remained high. It was concluded that norepinephrine-calorigenesis in the C-A rat is supported by a greater capacity to increase the cardiac output and an ability to preferentially reduce the systemic resistance to actively metabolizing areas (i.e., the viscera).

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A Mathematical Model of Heart Rate Control by Sympathetic and Vagus Efferent Information

SIMULATION ◽

10.1177/003754976400300114 ◽

1964 ◽

Vol 3 (1) ◽

pp. 63-71 ◽

Cited By ~ 17

Author(s):

Homer R. Warner ◽

Albert Cox

Keyword(s):

Mathematical Model ◽

Heart Rate ◽

Rate Control ◽

Heart Rate Control ◽

Dynamic Relation ◽

Chemical Events ◽

Physical And Chemical ◽

Frequency Of Stimulation ◽

Heart Rate Control System ◽

Stimulation Of

The effect on heart rate of stimulation of sympathetic and vagus efferent nerves to the heart has been described in a qualitative fashion by many investiga tors. However, except for the work of Rosenblueth and Simeone1 in 1934, no attempt has been made to analyze in a quantitative way the dynamic relation ship between heart rate and frequency of stimulation of these nerves. The present study was undertaken with the hope that such an analysis might yield useful information regarding a) the nature of the physical and chemical events involved in this transformation and b) the dynamic and steady-state parameters of this link of the heart rate control system.

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The Impact of Deep Y Descent on Hemodynamics in Patients With Heart Failure and Preserved Left Ventricular Systolic Function

Frontiers in Cardiovascular Medicine ◽

10.3389/fcvm.2021.770923 ◽

2021 ◽

Vol 8 ◽

Author(s):

Daisuke Harada ◽

Hidetsugu Asanoi ◽

Takahisa Noto ◽

Junya Takagawa

Keyword(s):

Heart Rate ◽

Systolic Function ◽

Left Ventricular Systolic Function ◽

Left Ventricular ◽

Atrial Pressure ◽

Right Atrial ◽

Right Atrial Pressure ◽

Pressure Waveform ◽

Ventricular Systolic Function ◽

The Right

Background: Influence of right ventricular diastolic function on the hemodynamics of heart failure (HF). We aimed to clarify the hemodynamic features of deep Y descent in the right atrial pressure waveform in patients with HF and preserved left ventricular systolic function.Methods: In total, 114 consecutive inpatients with HF who had preserved left ventricular systolic function (left ventricular ejection fraction ≥ 50%) and right heart catheterization were retrospectively enrolled in this study. The patients were divided into two groups according to right atrial pressure waveform, and those with Y descent deeper than X descent in the right atrial pressure waveform were assigned to the deep Y descent group. We enrolled another seven patients (two men, five women; mean age, 87 ± 6) with HF and preserved ejection fraction, and implanted a pacemaker to validate the results of this study.Results: The patients with deep Y descent had a higher rate of atrial fibrillation, higher right atrial pressure and mean pulmonary arterial pressure, and lower stroke volume and cardiac index than those with normal Y descent (76 vs. 7% p < 0.001, median 8 vs. 5 mmHg p = 0.001, median 24 vs. 21 mmHg p = 0.036, median 33 vs. 43 ml/m2p < 0.001, median 2.2 vs. 2.7 L/m2, p < 0.001). Multiple linear regression revealed a negative correlation between stroke volume index and pulmonary vascular resistance index (wood unit*m2) only in the patients with deep Y descent (estimated regression coefficient: −1.281, p = 0.022). A positive correlation was also observed between cardiac index and heart rate in this group (r = 0.321, p = 0.038). In the other seven patients, increasing the heart rate (from median 60 to 80/min, p = 0.001) significantly reduced the level of BNP (from median 419 to 335 pg/ml, p = 0.005).Conclusions: The hemodynamics of patients with HF with deep Y descent and preserved left ventricular systolic function resembled right ventricular restrictive physiology. Optimizing the heart rate may improve hemodynamics in these patients.

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Haemodynamics and Body Fluid Volumes in Response to Fluid Loading in Conscious Dogs: Non-Excretory Renal Influences

Clinical Science ◽

10.1042/cs0510243 ◽

1976 ◽

Vol 51 (3) ◽

pp. 243-255

Author(s):

J.-F. Liard

Keyword(s):

Heart Rate ◽

Cardiac Output ◽

Plasma Volume ◽

Interstitial Fluid ◽

Fluid Pressure ◽

Atrial Pressure ◽

Right Atrial ◽

Right Atrial Pressure ◽

Bilateral Nephrectomy ◽

Fluid Load

1. Twelve conscious, chronically instrumented dogs were subjected to rapid loading with sodium chloride solution (150 mmol/l; saline) before and 1 day after bilateral nephrectomy (six dogs) or uretero-caval anastomosis (six dogs). Measurements were performed up to 3 h after the fluid load and included cardiac output with an electromagnetic flowmeter, mean arterial pressure and right atrial pressure with chronically implanted catheters, interstitial fluid pressure with a plastic capsule, heart rate, extracellular fluid volume, erythrocyte volume, plasma volume, plasma protein concentration and other variables. 2. The increase in cardiac output in response to saline load was significantly prolonged in the anephric dogs compared with those with uretero-caval anastomosis; mean arterial pressure, right atrial pressure and heart-rate changes were similar in both groups. 3. Plasma volume appeared to increase more in the anephric dogs than in those with uretero-caval anastomosis during the first hour after the infusion, although conflicting results were obtained with different estimates of plasma volume changes. Interstitial fluid pressure increased significantly less in the anephric dogs in the early stages of the fluid load. 4. Effective vascular compliance (the ratio of the change in blood volume to the change in right atrial pressure) appeared increased in the anephric dogs. On the other hand, the change in cardiac output for a given change in right atrial pressure was found to increase after bilateral nephrectomy. 5. It is suggested that the prolonged increase in cardiac output observed in anephric dogs was not the consequence of preferential plasma volume expansion nor of decreased venous compliance, but may reflect an alteration in the cardiac function curve.

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Control of fetal cardiac output during changes in blood volume

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1980.238.1.h80 ◽

1980 ◽

Vol 238 (1) ◽

pp. H80-H86 ◽

Cited By ~ 12

Author(s):

R. D. Gilbert

Keyword(s):

Heart Rate ◽

Cardiac Output ◽

Blood Volume ◽

Atrial Pressure ◽

Right Atrial ◽

Right Atrial Pressure ◽

Volume Changes ◽

Fetal Sheep ◽

Systemic Pressure ◽

Mean Systemic Pressure

Changes in cardiac output (Qco), heart rate, right atrial pressure, (Pra), and mean systemic pressure (Pms) in response to blood volume changes were measured in chronically prepared fetal sheep. With a 10% decrease in blood volume, fetal cardiac output, measured with the microsphere technique, decreased significantly from 592 +/- 28 to 471 +/- 32 ml . min-1 . kg-1. Heart rate changed little from control animals (163 +/- 5) to those with decreased volume (161 +/- 10 beats/min). Right atrial pressure decreased significantly from 5.4 +/- 0.4 to 4.2 +/- 0.6 mmHg. Mean systemic pressure decreased from 13.8 +/- 0.3 to 10.5 +/- 0.6 mmHg. With a 10% increase in fetal blood volume, cardiac output rose insignificantly to 632 +/- 38 ml . min-1 . kg-1. However, right atrial pressure increased significantly to 8.9 +/- 0.6 mmHg and mean systemic pressure increased significantly to 16.5 +/- 0.8 mmHg with the increased volume. Heart rate again changed little (153 +/- 9 beats/min). The fact that cardiac output rose only a small amount, whereas right atrial pressure rose sharply with an increased blood volume, suggests that the fetal heart is operating near the upper limit of its Starling function curve. As a result, there is very limited cardiac reserve for increases in fetal cardiac output.

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