scholarly journals The effect of stretching the superior vena caval-right atrial junction on right atrial receptors in the dog

1972 ◽  
Vol 227 (3) ◽  
pp. 875-887 ◽  
Author(s):  
C. T. Kappagoda ◽  
R. J. Linden ◽  
H. M. Snow
Keyword(s):  
Superior Vena ◽  
Right Atrial ◽  
Superior Vena Caval ◽  
Atrial Receptors

"Summation" of the increase in heart rate from stimulation of atrial receptors

1980 ◽  
Vol 58 (6) ◽  
pp. 666-672
Author(s):  
P. V. Greenwood ◽  
C. T. Kappagoda
Keyword(s):  
Heart Rate ◽  
Left Atrial ◽  
Superior Vena ◽  
Right Atrial ◽  
Propranolol Hydrochloride ◽  
Superior Vena Caval ◽  
The Right ◽  
Atrial Receptors ◽  
Stimulation Of ◽  
Wire Cage

In dogs anaesthetized with chloralose, application of stimuli which are likely to activate left atrial (L.A.) and right atrial (R.A.) receptors (complex unencapsulated endings) has been shown to result in an increase in heart rate. The present investigation was undertaken to determine whether the response elicited by the application of one stimulus (i.e., to the left atrium) could be enhanced by the application of a second stimulus (i.e., to the right atrium) in the same animal.The L.A. receptors were stimulated by distending a small balloon at the right upper pulmonary vein-L.A. junction and the R.A. receptors by "expanding" a spherical wire cage positioned at the superior vena caval (S.V.C.)-R.A. junction. Pressures in the S.V.C., R.A., L.A., and femoral artery were measured and the electrocardiogram monitored.In eight dogs stimulation of L.A. receptors resulted in an increase in heart rate (H.R.) of 18.5 beats/min (SEM 6.0; N = 23). In the same animals stimulation of R.A. receptors resulted in an increase in H.R. of 14.6 beats/min (SEM 2.0; N = 25). Application of both stimuli simultaneously resulted in an increase of 32.2 beats/min (SEM 8.0; N = 13). In four dogs propranolol hydrochloride (0.5 mg/kg) markedly diminished the response. In three dogs the response was abolished by bretylium tosylate (10 mg/kg).It is concluded that the increase in H.R. resulting from the application of these two stimuli could be "summated" and these findings support the proposition that the receptors in the two atria act as a functional entity.

Widespread distribution and rate differentiation of the atrial pacemaker complex

1980 ◽  
Vol 239 (3) ◽  
pp. H406-H415 ◽  
Author(s):  
J. P. Boineau ◽  
R. B. Schuessler ◽  
D. B. Hackel ◽  
C. B. Miller ◽  
C. W. Brockus ◽  
...  
Keyword(s):  
Superior Vena ◽  
Sinus Node ◽  
P Wave ◽  
Right Atrial ◽  
Superior Vena Caval ◽  
Heart Rates ◽  
Widespread Distribution ◽  
Depolarization Wave ◽  
Lower Limits ◽  
Origin Point

In a study to examine the basis of rate-related changes in the electrocardiographic P wave we found a multicentric rather than unifocal origin of the atrial depolarization wave in dogs. Three to five pacemakers, or origin points, were distributed over a 30- to 40-mm area compared to the 11-mm size of the sinus node. Two or three of the sites could excite simultaneously, or one specific site would dominate excitation. Each separate origin point dominated excitation within a specific range of heart rates, and on reaching either the upper or lower limits of this range, a new focus abruptly dominated and initiated the atrial wave front. We have obtained evidence to suggest that these findings may be explained by a widely distributed atrial pacemaker complex. The spatial distribution of this system exceeded the dimensions of the canine sinus node by a factor of three to four times. The pacemaker centers, although distributed, were consistently located at specific positions along the superior vena caval-right atrial junction. Also, each separate pacemaker site appeared functionally differentiated to generate a specific range of heart rates. We propose that in addition to the sinus node there are other specialized atrial pacemaker centers, and that this specialization, including the differentiated response and coordination, is conferred by focal receptor characteristics and their inputs.

Atrial stretch-induced diuresis in Brattleboro rats

1987 ◽  
Vol 252 (3) ◽  
pp. R503-R506 ◽  
Author(s):  
S. Kaufman ◽  
J. Stelfox
Keyword(s):  
Renal Denervation ◽  
Superior Vena ◽  
Urine Volume ◽  
Right Atrial ◽  
Brattleboro Rats ◽  
Brattleboro Rat ◽  
Superior Vena Caval ◽  
Urine Sodium ◽  
Water Output ◽  
Urine Potassium

Inflation of a balloon at the superior vena caval/right atrial junction of the conscious Brattleboro rat initiated a rapid and significant diuresis, natriuresis, and kaliuresis (urine volume increased from 20.8 +/- 0.8 to 28.5 +/- 1.3 ml/h, P less than 0.005; urine sodium increased from 2,417 +/- 115 to 3,510 +/- 230 mu eq/h, P less than 0.005; urine potassium increased from 351 +/- 52 to 478 +/- 58 mu eq/h, P less than 0.05; n = 6). Bilateral renal denervation did not significantly alter this response. Since the Brattleboro rat is totally deficient in antidiuretic hormone (ADH) and since inflation of the balloon causes no change in blood pressure, the reflex increase in urinary salt and water output must be mediated, at least in part by a blood-borne factor other than ADH.

Influence of venous injection sites on evolution of dilution curves in dogs

1963 ◽  
Vol 205 (3) ◽  
pp. 504-510
Author(s):  
Ramon L. Lange ◽  
James T. Botticelli
Keyword(s):  
Pulmonary Artery ◽  
Femoral Artery ◽  
Inferior Vena ◽  
Superior Vena ◽  
Right Atrial ◽  
Superior Vena Caval ◽  
Right Heart ◽  
Inferior Vena Caval ◽  
The Right ◽  
Dilution Curves

The role of venous passage of indicator from different venous injection sites on the genesis of right heart and pulmonary artery dilution curves was examined. Right heart and pulmonary artery thermodilution curves were recorded after injection of cool dye into commonly used portals—superior vena caval, right atrial, and inferior vena caval—and the contour compared with the subsequent femoral artery dye dilution curve. With superior vena caval or right atrial injection, the contour and disappearance slopes of the pulmonary artery curve bore an extremely variable relationship to those of the femoral artery curve. In sharp contrast, inferior vena caval injection yielded pulmonary artery curves with disappearance slopes which were highly correlated with the femoral artery slope ( r = .99). With inferior vena caval injection, considerable temporal dispersion and spatial dispersion of indicator is found at the right atrial level. With superior vena caval injection distribution mainly occurred beyond the right atrium and even beyond the pulmonary artery in eight out of ten animal studies. The geometry of the venous system may explain this difference. Inaccuracies in flow calculation from right heart dilution curves in dogs would seem to be minimized by inferior vena caval injection.

Effect of stimulating right atrial receptors on renal blood flow

1982 ◽  
Vol 60 (12) ◽  
pp. 1672-1679 ◽  
Author(s):  
F. Karim ◽  
S. Kaufman ◽  
C. T. Kappagoda
Keyword(s):  
Blood Flow ◽  
Renal Mass ◽  
Carotid Sinus ◽  
Superior Vena ◽  
Renal Perfusion ◽  
Right Atrial ◽  
Myelinated Fibres ◽  
Right Atrial Appendage ◽  
The Right ◽  
Atrial Receptors

This investigation was undertaken to determine the effect of stretching the superior vena caval – right atrial (SVC–RA) junction and the right atrial appendage on blood flow to the kidney (RBF) and to establish whether any changes observed were influenced by the input from the baroreceptors in the carotid sinus. The experiments were performed on seven dogs, anaesthetized with α-chloralose. The systemic arterial (i.e., renal perfusion) pressure was held constant. At a carotid sinus pressure (CSP) of 59.0 ± 1.2 mmHg (1 mmHg = 133.322 Pa), the RBF increased from 218 ± 16.1 to 231.7 ± 18.4 mL/min per 100 g renal mass (p < 0.025). At a CSP of 88.0 ± 3.5 mmHg, the RBF increased from 230.1 ± 19.2 to 237.1 ± 19.2 mL/min per 100 g renal mass (p < 0.05). At a CSP of 137 ± 3.7 mmHg there were no significant changes in RBF. These responses were abolished by cutting (four dogs) or cooling the vagi (one dog only). In a subsidiary investigation it was shown that stretching the SVC–RA junction activated receptors in the endocardial surface of the right atrium which discharged into myelinated fibres in the vagi, having an average conduction velocity of 8.1 m/s (range 3.8–15). It is concluded that stimulation of right atrial receptors increases the RBF and that this response is influenced by the input from the barorceptors in the carotid sinus.

Effect of pregnancy on activation of central pathways following atrial distension

1995 ◽  
Vol 269 (3) ◽  
pp. R552-R556 ◽  
Author(s):  
Y. Deng ◽  
S. Kaufman
Keyword(s):  
Preoptic Area ◽  
Superior Vena ◽  
Lateral Septum ◽  
Right Atrial ◽  
Ventrolateral Medulla ◽  
Atrial Volume ◽  
Superior Vena Caval ◽  
Hypothalamic Area ◽  
Homeostatic Mechanisms ◽  
Stimulation Of

Stimulation of the atrial volume receptors increases neural traffic to the ventrolateral medulla, which in turn sends output to, and receives input from, the lateral hypothalamic area. An integrated reflex and hormonal response is thus initiated. We wished to investigate first whether atrial distension results in activation of selected nuclei in the forebrain and, second, whether pregnancy modifies this response. Rats were implanted with indwelling intracardiac balloons positioned at the superior vena caval/right atrial junction. One week later, the balloons were inflated. The animals were then anesthetized, their brains fixed by perfusion, and the tissue prepared for visualization of c-fos activity. Atrial distension caused a significant increase in c-fos expression in the paraventricular nucleus, the medial preoptic area, and the lateral septum. This response was markedly attenuated in the pregnant animals. In conclusion, during pregnancy central pathways that are normally activated in responses to volume expansion, fail to respond to atrial distension. We propose that this allows blood volume to increase in the pregnant animal, without triggering homeostatic mechanisms.

Superior vena caval blood flow velocities in adults: a Doppler echocardiographic study

1986 ◽  
Vol 61 (1) ◽  
pp. 215-219 ◽  
Author(s):  
M. L. Cohen ◽  
B. S. Cohen ◽  
I. Kronzon ◽  
G. W. Lighty ◽  
H. E. Winer
Keyword(s):  
Blood Flow ◽  
Flow Velocity ◽  
Peak Flow ◽  
Superior Vena ◽  
Right Atrial ◽  
Superior Vena Caval ◽  
Noninvasive Technique ◽  
Supraclavicular Fossa ◽  
Antegrade Flow ◽  
Flow Velocities

Superior vena caval blood flow velocity was measured in 30 normal adults (age 20–65, mean 36 yr). The flow velocities were measured by pulsed Doppler echocardiography, using a Duplex system with the transducer at the right supraclavicular fossa, approximating a 0 degrees Doppler angle. Four distinct flow waveforms were found during each cardiac cycle: A, a small retrograde flow during right atrial contraction (peak flow velocity 12.4 +/- 2.2 cm/s); B, a small antegrade flow during right atrial relaxation (15.7 +/- 5.0 cm/s); S, a large antegrade flow during ventricular systole (35.2 +/- 7.3 cm/s); and D, a large antegrade flow during ventricular diastole (23.2 +/- 3.1 cm/s). The wave duration was inversely related to heart rate. The peak flow velocities of the S and D waves were inversely related to the patients' ages. This study provides recognition of the pattern and range of normality essential to extension of this noninvasive technique to the diagnosis of pathological conditions.

Echocardiographic Detection of an Infected Superior Vena Caval Thrombus Presenting as a Right Atrial Mass

CHEST Journal ◽  
1989 ◽  
Vol 96 (1) ◽  
pp. 212-214 ◽  
Author(s):  
Andrew E. Dick ◽  
Charles M. Gross ◽  
Joseph W. Rubin
Keyword(s):  
Superior Vena ◽  
Right Atrial ◽  
Superior Vena Caval ◽  
Atrial Mass ◽  
Right Atrial Mass
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