The relationship between plasma vasopressin concentration and urinary excretion during left atrial distension in anaesthetized dogs

1984 ◽  
Vol 400 (4) ◽  
pp. 381-387 ◽  
Author(s):  
J. R. Ledsome ◽  
N. Wilson

1982 ◽  
Vol 60 (9) ◽  
pp. 1210-1218 ◽  
Author(s):  
J. R. Ledsome ◽  
N. Wilson ◽  
J. Ngsee

Distension of the left atrium in chloralose anaesthetized dogs causes a diuresis and dilution of the urine. It has been reported previously that if distension of the atrium is maintained then urine flow reaches a peak after 50 min and then declines. A radioimmunoassay was used to measure plasma arginine vasopressin (AVP) at 10-min intervals before, during, and after atrial distension for 90 min. Plasma AVP decreased during atrial distension and did not increase until after the atrial distension was removed.Urine volume and free-water clearance increased and urine osmolality decreased, to reach maximum changes after 50 min. Although there was then a decline in some experiments, after reaching the peak changes, the mean values of the group did not show any statistically significant decline. Thus the urinary changes were also present for the 90 min of left atrial distension. The results are consistent with the hypothesis that the.diuretic response to left atrial distension is dependent upon decreased release of AVP from the neurohypophysis.



Author(s):  
Alexander Romanov ◽  
Stanislav Minin ◽  
Nikita Nikitin ◽  
Dmitry Ponomarev ◽  
Vitaly Shabanov ◽  
...  


1995 ◽  
Vol 268 (6) ◽  
pp. R1411-R1417
Author(s):  
D. Javeshghani ◽  
S. Mukaddam-Daher ◽  
L. Fan ◽  
Z. Guan ◽  
J. Gutkowska ◽  
...  

Previous studies of the atrial stretch-atrial natriuretic factor (ANF) relationship during pregnancy have employed volume expansion and measured only right atrial pressure (RAP). Consequently, we studied nonpregnant (n = 7) and 115- to 125-day pregnant (n = 7) sheep and assessed the ANF response to changes of RAP and left atrial pressure (LAP) induced by graded balloon inflation. Ewes prepared with vascular catheters and atrial balloons were studied after recovery from preparatory surgical procedures. The basal levels of mean arterial pressure (MAP, 83 +/- 3 mmHg), RAP (2.1 +/- 0.7 mmHg), LAP (4.7 +/- 0.9 mmHg), and heart rate (HR, 102 +/- 6 beats/min) were similar in nonpregnant and pregnant sheep. Pregnancy also resulted in elevation of ANF concentration from 25 +/- 6 to 57 +/- 4 fmol/ml. With right atrial distension, the RAP-ANF relationships were similar in both nonpregnant and pregnant sheep, with a 10-mmHg increase in RAP increasing ANF by an average of 95 +/- 9 fmol/ml. In nonpregnant sheep, the LAP-ANF relationship was more responsive than RAP-ANF because a 10-mmHg increase in LAP resulted in a 193 +/- 10 fmol/ml increase in ANF. Moreover, during pregnancy, the LAP-ANF relationship was significantly more sensitive because a 10-mmHg increase in LAP resulted in a 433 +/- 15 fmol/ml elevation of ANF. These data demonstrate that plasma ANF levels are more responsive to distension of the left atria than to the right. More importantly, the ANF response to left, but not right, atrial distension is enhanced by pregnancy.



2013 ◽  
Vol 112 (1-3) ◽  
pp. 49-55 ◽  
Author(s):  
Tao Ma ◽  
Kaidong Deng ◽  
Chenggang Jiang ◽  
Yan Tu ◽  
Naifeng Zhang ◽  
...  


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Fengpeng Jia ◽  
Minghuan Fu ◽  
Zhiyu Ling ◽  
Suxin Luo ◽  
Jun Gu ◽  
...  

Background: The study was to evaluate the value of CHADS2 and CHADS2VASC scores on predicting left atrial (LA) thrombus in the patients with atrial fibrillation (AF). Methods and Results: All the non-valvular AF patients undergoing AF ablation from June 2010 to June 2012 were included and divided into two groups: patients without anticoagulation and with Coumadin anticoagulation for at least 4 weeks. The relationship between CHADS2 and CHADS2VASC scores and LA thrombus as identified on transesophageal echocardiography (TEE) was analyzed prior to ablation. A total of 397 patients underwent pre-ablation TEE: 212 patients without anticoagulation, and 185 with anticoagulation. There were no differences in the CHADS2 and CHADS2VASC scores in the two groups. LA thrombus was present in 15.6% and 5.9% for the patients without anticoagulation and for those with anticoagulation, respectively (p = 0.002). There was a strong association between CHADS2 and LA thrombus, and between CHADS2VASC and LA thrombus in the two groups. No thrombus was identified in patients with CHADS2VASC score of 0 in both groups. However, thrombus was detected in 3.5% of patients with CHADS2 score of 0 in the group without anticoagulation, while no thrombus was present in the ones with anticoagulation. CHADS2VASC score of ≥1 (r=2.03, p = 0.04) was the only factor independently associated with LA thrombus in patients without anticoagulation, while both CHADS2VASC score of ≥2 (r=2.61, p=0.02) and CHADS2 score of ≥2 (r=2.73, p=0.01) were independently associated with LA thrombus. Further analyses showed that CHADS2VASC score was a better predictor for LA thrombus than CHADS2 score in patients without anticoagulation. However, there was no difference between the two scoring systems in predicting LA thrombus in patients with anticoagulation. Conclusions: LA thrombus was associated with CHADS2VASC and CHADS2 scores in non-valvular AF patients without anticoagulation. CHADS2VASC score was a better predictor than CHADS2 score for LA thrombus in patients without anticoagulation. The data suggested that it might be unnecessary to undergo a TEE evaluation for LA thrombus in low risk patients identified by CHADS2VASC score regardless anticoagulation therapy prior to cardioversion or ablation.



1980 ◽  
Vol 238 (4) ◽  
pp. E313-E317 ◽  
Author(s):  
M. Hammer ◽  
J. Ladefoged ◽  
K. Olgaard

The relationship between plasma osmolality (pOsm) and plasma vasopressin (pAVP) was studied in 13 human subjects during dehydration. The fit of linear, log-linear, parabolic, and exponential models was tested. For all of the data, the nonlinear models had the best fit. However, when individual differences in either gain or threshold were allowed for, the linear models were better than log-linear models. Finally, analyses were made with individual data points. Linear models had the best fit in half of the subjects, whereas for the others the parabolic model gave the best fit. For those subjects investigated in the low range of the osmoregulatory curve, a linear relationship was found, whereas, for those having the most pronounced increase in pOsm, the most significant improvement was found with the parabolic model. This finding indicates that the relationship is not stable during dehydration in the whole range and that hypovolemia probably can influence the secretion rate and/or metabolic clearance rate and thereby the relationship.



2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lei Chen ◽  
Changjiang Xu ◽  
Wensu Chen ◽  
Chaoqun Zhang

Abstract Background Thromboembolic events are the most serious complication of atrial fibrillation (AF), and the left atrial appendage (LAA) is the most important site of thrombosis in patients with AF. During the period of COVID-19, a non-invasive left atrial appendage detection method is particularly important in order to reduce the exposure of the virus. This study used CT three-dimensional reconstruction methods to explore the relationship between LAA morphology, LAA orifice area and its mechanical function in patients with non-valvular atrial fibrillation (NVAF). Methods A total of 81 consecutive patients with NVAF (36 cases of paroxysmal atrial fibrillation and 45 cases of persistent atrial fibrillation) who were planned to undergo catheter radiofrequency ablation were enrolled. All patients were examined by transthoracic echocardiography (TTE), TEE, and computed tomography angiography (CTA) before surgery. The LAA orifice area was obtained according to the images of CTA. According to the left atrial appendage morphology, it was divided into chicken wing type and non-chicken wing type. At the same time, TEE was performed to determine left atrial appendage flow velocity (LAAFV), and the relationship between the left atrial appendage orifice area and LAAFV was analyzed. Results The LAAFV in Non-chicken wing group was lower than that in Chicken wing group (36.2 ± 15.0 cm/s vs. 49.1 ± 22.0 cm/s, p-value < 0.05). In the subgroup analysis, the LAAFV in Non-chicken wing group was lower than that in Chicken wing group in the paroxysmal AF (44.0 ± 14.3 cm/s vs. 60.2 ± 22.8 cm/s, p-value < 0.05). In the persistent AF, similar results were observed (29.7 ± 12.4 cm/s vs. 40.8 ± 17.7 cm/s, p-value < 0.05). The LAAFV in persistent AF group was lower than that in paroxysmal AF group (34.6 ± 15.8 cm/s vs. 49.9 ± 20.0 cm/s, p-value < 0.001). The LAAFV was negatively correlated with left atrial dimension (R = − 0.451, p-value < 0.001), LAA orifice area (R= − 0.438, p-value < 0.001) and left ventricular mass index (LVMI) (R= − 0.624, p-value < 0.001), while it was positively correlated with LVEF (R = 0.271, p-value = 0.014). Multiple linear regression analysis showed that LAA morphology (β = − 0.335, p-value < 0.001), LAA orifice area (β = −  0.185, p-value = 0.033), AF type (β = − 0.167, p-value = 0.043) and LVMI (β = − 0.465, p-value < 0.001) were independent factors of LAAFV. Conclusions The LAA orifice area is closely related to the mechanical function of the LAA in patients with NVAF. The larger LAA orifice area and LVMI, Non-chicken wing LAA and persistent AF are independent predictors of decreased mechanical function of LAA, and these parameters might be helpful for better management of LA thrombosis.





1998 ◽  
Vol 1998 ◽  
pp. 80-80
Author(s):  
F. Herrera Gomez ◽  
F. D. Deb Hovell ◽  
C. A. Sandoval Castro

Studies in the use of the purine derivatives technique in ruminants have been stimulated by the possible use of this technique as an estimator of the rumen microbial-N supplied to the host animal. The recovery factor influences the estimation of the total purines absorbed and therefore the microbial-N supply. The relationship between exogenous purine input and urinary excretion and recovery has been studied using cattle maintained with the intragastric infusion technique (Orskov et al., 1979). The urinary recovery of exogenous purines has been estimated to be 0.77-0.85 (Chen et al., 1990a, Verbic et al., 1990), and this relationship has been assumed to be applicable to normal feeding situations. To our knowledge there is no data to support or reject this approach. This study examined the urinary recovery of exogenous allantoin input in steers under normal feeding conditions.



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