Effects of Angiotensin II and Aldosterone on Diastolic Function In Vivo in Normal Man

1994 ◽  
Vol 87 (4) ◽  
pp. 397-401 ◽  
Author(s):  
P. B. M. Clarkson ◽  
N. M. Wheeldon ◽  
C. MacLeod ◽  
M. Tennent ◽  
T. M. MacDonald

1. Doppler echocardiographic indices of diastolic function and systemic haemodynamics were studied in response to infusions of angiotensin II (1, 2, 5 and 10 ng min−1 kg−1), D-aldosterone (2, 4, 10 and 20 ng min−1 kg−1) and placebo [0.9% (w/v) NaCl] in ten normal male subjects. 2. Dose-related increases in systolic and diastolic blood pressure were observed with angiotensin II infusion at rates of 2 ng min−1 kg−1 and above, whereas no changes in blood pressure occurred with D-aldosterone. No changes in aortic stroke distance or heart rate were seen with either angiotensin II or aldosterone infusion. 3. Compared with placebo, angiotensin II infusion produced a dose-related prolongation of the isovolumic relaxation time [mean and 95% confidence intervals 12.0 (8.2–15.8) ms, P < 0.001] at 10 ng min−1 kg−1, and a significant reduction in the ratio between early and late transmitral flow velocity integrals at 2 ng min−1 kg−1, [−0.84 (−1.63 to −0.05), P < 0.05] and 5 ng min−1 kg−1 [−0.76 (−1.47 to −0.05), P < 0.05]. No changes in Doppler echocardiographic indices of diastolic function were observed with D-aldosterone infusion. 4. These data suggest that angiotension II, even at a sub-pressor concentration, produces an impairment of left ventricular diastolic filling, which occurs independently of its effect on aldosterone release.

1972 ◽  
Vol 43 (6) ◽  
pp. 839-849 ◽  
Author(s):  
E. C. Osborn ◽  
G. Tildesley ◽  
P. T. Pickens

1. The pressor responses to angiotensin I were compared with those to angiotensin II after injections into the left ventricle and jugular vein in the sheep, dog and pig. 2. The ability of angiotensin I to raise the blood pressure was less than that of angiotensin II with both routes of injection, a difference which was more marked after ventricular injection. 3. When equipressor doses of the hormones were given there was a delay of 1–3 s in the onset of the pressor response to angiotensin I compared with angiotensin II after left-ventricular injections; the difference in the delay in onset was less apparent with intravenous injections. 4. The development of the pressor responses was similar with both hormones when equipressor doses were used but the rises in blood pressure were more prolonged with angiotensin I, especially when given by the left-ventricular route. 5. The in vitro rate of activation of angiotensin I by blood was much slower than the apparent in vivo formation of angiotensin II.


1994 ◽  
Vol 87 (s31) ◽  
pp. 11P-11P
Author(s):  
Pbm Clarkson ◽  
TM Macdonald ◽  
C Macleod ◽  
NM Wheeldon

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Stefano Toldo ◽  
Carlo Marchetti ◽  
Aysar Al Husseini ◽  
Salvatore Carbone ◽  
Jessica Regan ◽  
...  

Introduction: Heart failure with preserved ejection fracture (HFpEF) is a clinical syndrome of HF symptoms associated with impaired diastolic function. Although it represents approximately 50% of all patients with HF, the mechanisms of disease are poorly understood, animal models of HFpEF not due pressure overload are lacking, and therapies for HFpEF are generally ineffective. Hypothesis: A continuous infusion of low dose of angiotensin II (ATII) may be sufficient to induce changes in left ventricular (LV) diastolic function without increasing blood pressure nor induce LV hypertrophy. Methods: Osmotic pumps were implanted subcutaneously in 8 week-old CD1 male mice randomly assigned to the ATII (200 ng/kg/day) or vehicle (N=8/group). Transthoracic echocardiography was performed at baseline and 4 weeks to measure LV dimensions, systolic and diastolic function. Aortic systolic and diastolic pressures (AoP), LV peak systolic and end-diastolic pressures (LVPSP, LVEDP) were measured at LV catheterization. Fibrosis was measured using Masson’s trichrome stain. The expression of Interleukin (IL)-18 mRNA levels, a cytokine associated with impaired cardiomyocyte relaxation, was measured at 4 weeks. Results: When compared to the baseline values or vehicle group, ATII infusion had no effects on AoP, LVPSP and HR, and had no effects on LV dimensions or mass, nor on LVEF (all P>0.2). ATII induced a significant impairment in LV diastolic function as measured by an increase (worsening) of the myocardial performance index (MPI), the LV isovolumetric relaxation time (IVRT) and of LVEDP (Figure). Cardiac expression of IL-18 mRNA was significantly increased 7-fold after ATII infusion (P<0.001), suggesting a potential mechanistic role of IL-18. Conclusion: Chronic infusion of low dose ATII recapitulates the HFpEF phenotype in the mouse, without increasing blood pressure. The use of this mouse model may help understanding the mechanisms leading to HFpEF syndrome in patients.


2021 ◽  
Vol 25 (4) ◽  
pp. 577-583
Author(s):  
T. Yu. Niushko ◽  
E. S. Osiadla

Annotation. Arterial hypertension (AH) is one of the most important risk factors for the development of cardiovascular complications and mortality in the world and it has become a medical and social problem. The prevalence of hypertension will increase to 1.56 billion by 2025, making the disease a very serious problem. The severity of clinical manifestations and prognosis in patients with hypertension are determined not only by the degree of increase in blood pressure (BP) but also the damage to target organs. The load on the cardiovascular system caused by elevated BP leads to structural remodelling of the heart and vessels. The aim – to evaluate peculiarities of indicators of ambulatory blood pressure monitoring in patients with essential hypertension of the 2nd stage depending on the type of 24-hours blood pressure profile, the state of the left ventricular diastolic filling and endothelial function of the vessels and determine independent clinical and instrumental criteria of the 24-hours profile “dipper” and “non-dipper”. The study involved 110 patients (40 men and 70 women) with hypertension of the II-nd stage, hypertensive heart, chronic heart failure of the 0-I stage (average age was 54.19±0.89 years). The patients underwent 24-hour blood pressure monitoring, echocardiography and determination the thickness of the intima-media complex (IMCT) of the brachial artery, endothelium-dependent (EDVD) and endothelium-independent (EIVD) vasodilatation. For statistical analysis, arithmetic means (M), errors of mean values (m), t - Student's t test for paired measurements were calculated. Correlation ratios were evaluated by the method of linear correlation for parametric data and the method of Spearman’s rank correlation for nonparametric data. Paired group comparisons were performed by the nonparametric Mann-Whitney method. Wilcoxon test was used in the analysis of dependent samples. Step-by-step multifactor regression was used to identify independent criteria for daily blood pressure profiles. Two types of 24-hours profile of blood pressure – “dipper” and “non-dipper” were detected. The left ventricle diastolic dysfunction (LVDD) by type of relaxation disorder was observed in all “non-dipper” patients and most “dipper” patients. Patients with DD had higher levels of BP per 24-hours, day, night, corresponding the time indexes, the magnitude of the morning increase of systolic and diastolic blood pressure, more pronounced structural changes of the heart and vessels compared with patients with preserved diastolic filling of the LV(р<0,01). The duration of the hypertensive anamnesis (p=0.0002), the thickness of the posterior wall of the LV (p=0.002), the maximum speed of early diastolic filling of the LV (E) (p<0.0001), the LV ejection fraction (p=0.001), the index of the left atrium (p=0.008), the thickness of the intima-media complex of the brachial artery (p=0.013), increase of the diameter of the brachial artery in 90 s after compression (EDVD) (p<0.0001) and in 5 min after taking of nitroglycerin (EIVD) (p=0.009) were determined as independent clinical and instrumental criteria of the “dipper” and “non-dipper” profile. Insufficient the degree of the nightly decrease of the BP, higher magnitude of the morning increase of systolic and diastolic BP cause more hemodynamic pressure on target organs and lead to more significant pathological remodeling of the LV and vessels, disorders of the LV relaxation processes and endothelial dysfunction.


1999 ◽  
Vol 7 (3) ◽  
pp. 214-220 ◽  
Author(s):  
Azad Akkoç ◽  
Berzal Uçaman ◽  
Halil Kaymak ◽  
Ali Vahip Temamoğullari ◽  
Kenan Iltümür ◽  
...  

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