scholarly journals Left ventricular and proximal aorta coupling in magnetic resonance imaging: aging together?

2019 ◽  
Vol 317 (2) ◽  
pp. H300-H307 ◽  
Author(s):  
Alban Redheuil ◽  
Nadjia Kachenoura ◽  
Emilie Bollache ◽  
Wen-Chung Yu ◽  
Anders Opdahl ◽  
...  
Keyword(s):  
Total Peripheral Resistance ◽  
Characteristic Impedance ◽  
Myocardial Strain ◽  
Peripheral Resistance ◽  
Wall Stress ◽  
Aortic Distensibility ◽  
Left Ventricular ◽  
Ascending Aorta ◽  
Left Ventricular Geometry ◽  
Age Related

The importance of aorta-ventricular coupling in cardiovascular disease is recognized but underestimated. The contribution of the age-related decline in ascending aortic function compared with characteristic impedance and total peripheral resistance on left ventricular function and remodeling is poorly studied. Our aim was to evaluate the relation of proximal aortic distensibility and impedance with left ventricular geometry and function in asymptomatic individuals. We prospectively studied 100 subjects (47 men, 53 women, age: 20–84 yr). Aortic strain, distensibility, arch pulse wave velocity, characteristic impedance ( Zc), total peripheral resistance, left ventricular (LV) volumes and mass, wall stress, and peak global circumferential myocardial strain and strain rates were determined by MRI. Central pressures were measured from tonometry. Ea/ Ev, an index of vascular-ventricular coupling, and LV wall stress were preserved across age- or aortic-stiffness-stratified groups. Static and pulsatile components of aortic load were differentially associated with age. Increased total vascular resistance was associated with decreased LV strain and increased concentric remodeling [ratio of LV mass to end-diastolic volume (M/V ratio)] in all individuals. In younger individuals (<45 yr), aortic distensibility was related to LV strain and concentric remodeling (M/V ratio), whereas Zc was related to LV strain and concentric remodeling (M/V ratio) in older individuals (>45 yr). Early age-related stiffening of the ascending aorta is a component of LV afterload subsequently associated with increased aortic impedance and alterations in LV geometry, namely concentric remodeling, decreased myocardial strain, and increased stroke work such that LV wall stress and arterial-ventricular coupling are preserved. NEW & NOTEWORTHY Local flow and deformation can both be assessed with high precision noninvasively in the ascending aorta using MRI. Combined with central pressure measurement, they provide distensibility and impedance and simultaneous reference assessment of left ventricular deformation and geometry, hence a comprehensive evaluation of arterial-ventricular coupling to study physiology and disease.

Effects of arterial input impedance on mean ventricular pressure-flow relation

1984 ◽  
Vol 247 (6) ◽  
pp. H978-H983 ◽  
Author(s):  
W. L. Maughan ◽  
K. Sunagawa ◽  
K. Sagawa
Keyword(s):  
Characteristic Impedance ◽  
Peripheral Resistance ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Pressure Flow ◽  
Inotropic State ◽  
End Diastolic Volume ◽  
State Compliance ◽  
Slope Change

The mean left ventricular pressure-flow relationship (Pv-Fv), determined under a constant preload and variable peripheral resistance, has been proposed as a quantitative representation of ventricular pump function (9). We determined the Pv-Fv relation in seven isolated cross-perfused canine hearts by varying resistance of a simulated arterial load in five steps from 6.0 to 0.375 mmHg X s X ml-1 while keeping end-diastolic volume, inotropic state, compliance, and characteristic impedance at various constant values. All of the 27 Pv-Fv relations thus determined were moderately nonlinear. Varying end-diastolic volume at three levels shifted the relation curve in an approximately parallel fashion (P less than 0.0001). At three levels of inotropic state (mean LVP of isovolumic contractions 34.3 +/- 8.2, 48.0 +/- 6.3, and 59.2 +/- 9.6 mmHg), the Pv-Fv relation shifted with predominantly a slope change (P less than 0.0001). Changing compliance at three levels (0.2, 0.4, and 0.8 ml/mmHg) caused a statistically significant but quantitatively small crossover of the Pv-Fv curves (P less than 0.0001). Changing characteristic impedance to 0.1, 0.2, and 0.4 mmHg X s X ml-1 caused a highly significant (P less than 0.0001) divergence of Pv-Fv relation over the high Fv range. We conclude that this sensitivity of the Pv-Fv relation to characteristic impedance limits its use as a contractility index.

Plasma Noradrenaline Concentrations and Haemodynamics in the Early Stage of Essential Hypertension

1978 ◽  
Vol 55 (s4) ◽  
pp. 69s-71s ◽  
Author(s):  
Y. Miura ◽  
K. Kobayashi ◽  
H. Sakuma ◽  
H. Tomioka ◽  
M. Adachi ◽  
...  
Keyword(s):  
Essential Hypertension ◽  
Mean Arterial Pressure ◽  
Cardiac Index ◽  
Arterial Pressure ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Young Patients ◽  
Plasma Noradrenaline ◽  
Age Related ◽  
Wide Range

1. Plasma noradrenaline concentrations and haemodynamic status were simultaneously studied in young patients with uncomplicated essential hypertension and in age-matched normal controls. 2. Resting plasma noradrenaline in the controls tended to increase slightly, but progressively, with age. The hypertensive subjects had significantly higher plasma noradrenaline concentrations than those in the controls, but these values did not show any age-related variation. The response of plasma noradrenaline to the standing position tended to increase with age in the controls, whereas plasma noradrenaline in the hypertensive subjects showed a wide range of responses without any fixed relationship with age. 3. The cardiac index was significantly greater in the labile hypertensive subjects than in the controls, whereas total peripheral resistance was significantly greater in the sustained hypertensive subjects than in the labile patients and in the controls. Mean arterial pressure in these patients was closely related with the values of total peripheral resistance rather than with the cardiac index. 4. Of the patients with raised plasma noradrenaline 80% showed significantly increased values of either total peripheral resistance or cardiac index. Plasma noradrenaline was correlated significantly to total peripheral resistance, and marginally to mean arterial pressure. 5. These findings support the view that sympathetic nervous overactivity is an important factor underlying the haemodynamic findings in these patients.

Wall stress misrepresents afterload in children and young adults with abnormal left ventricular geometry

2002 ◽  
Vol 92 (3) ◽  
pp. 1053-1057 ◽  
Author(s):  
Thomas L. Gentles ◽  
Steven D. Colan
Keyword(s):  
Normal Population ◽  
Wall Stress ◽  
Left Ventricular ◽  
Left Ventricular Geometry ◽  
Z Score ◽  
Fiber Stress ◽  
Ventricular Geometry ◽  
Wide Range ◽  
Z Scores ◽  
The Difference

Wall stress, although commonly used as an index of afterload, fails to take into account forces generated within the wall of the left ventricle (LV) that oppose systolic fiber shortening. Wall stress may, therefore, misrepresent fiber stress, the force resisting fiber shortening, particularly in the presence of an abnormal LV thickness-to-dimension ratio ( h/ D). M-mode LV echocardiograms were obtained from 207 patients with a wide range of values for LV mass and/or h/ D. Diagnoses were valvar aortic stenosis, coarctation repair, anthracycline treated, and severe aortic and/or mitral regurgitation. End-systolic wall stress (WSes) and fiber stress (FSes) were expressed as age-corrected Z scores relative to a normal population. The difference between WSes and FSes was extreme when h/ D was elevated or reduced [WSes Z score − FSes Z score = 0.14 × ( h/ D)−1.47 − 2.13; r = 0.78, P < 0.001], with WSes underestimating FSes when h/ D was increased and overestimating FSes when h/ D was decreased. Analyses of myocardial mechanics based on wall stress have limited validity in patients with abnormal ventricular geometry.

Age-Specific Features of the Functional Development of the Circulatory System in Children Living in Northeastern Russia

2021 ◽  
pp. 34-38
Author(s):  
LI Grechkina ◽  
VO Karandasheva
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Peripheral Resistance ◽  
Left Ventricular ◽  
Human Interaction ◽  
Northeastern Russia ◽  
Special Importance ◽  
Functional Development ◽  
Age Related ◽  
Study Results

Summary. Introduction: The problem of human interaction with the environment acquires special importance nowadays. Significant migration processes observed in the last decade have become global, thus necessitating studies of the mechanisms of human adaptation to new environmental conditions. Our objective was to study age-related changes in functional indices of the cardiovascular system in adolescents between 11 and 17 years of age, born in Magadan in the first to third generation of Caucasians who had migrated to this city. Material and methods: In all, 1,442 school-age adolescents were examined including 809 boys and 633 girls. The main anthropometric parameters (body weight, kg, and height, cm) were measured and cardiac hemodynamics was determined at rest in the sitting position by volumetric compression oscillometry using a non-invasive hard- and software unit for central hemodynamic study. Results: Significantly higher values of cardiac output and stroke volume prevailed in boys of all age groups. The boys aged 14-17 years also demonstrated higher values of systolic blood pressure and left ventricular power output compared to girls. At the same time, the girls had higher age-specific indices of the heart rate, diastolic blood pressure, and total peripheral resistance. Conclusion: We established that the highest rates of cardiovascular functional development occur during puberty in 11 to 16-year-old boys and 11 to 13-year-old girls. Our findings showed that only 70.2 % to 77.2 % of the boys and 75.1 % to 80.2 % of the girls had blood pressure and heart rate readings within the age norm. Prehypertension was registered in 11.3 % and 10.3 % while hypertension was observed in 11.5 % and 9.5 % of the examined boys and girls, respectively. Tachycardia at rest was noted in 18 % of the boys and 20.2 % of the girls.

Cardiac performance enhancement from dobutamine in patients refractory to hypervolemic therapy for cerebral vasospasm

1993 ◽  
Vol 79 (4) ◽  
pp. 494-499 ◽  
Author(s):  
Michael L. Levy ◽  
Craig H. Rabb ◽  
Vladimir Zelman ◽  
Steven L. Giannotta
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Cardiac Index ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Left Ventricular ◽  
Cardiac Performance ◽  
Beta Agonist ◽  
Volume Index ◽  
Stroke Work ◽  
Hyperdynamic Therapy

✓ The use of the beta-agonist dobutamine in combination with hypervolemic preload enhancement of cardiac performance was analyzed in 23 patients who failed to respond to traditional preload enhancement following aneurysmal subarachnoid hemorrhage. The patients ranged in age from 13 to 82 years, and three had a history of cardiac disease. Each patient underwent placement of a flow-directed balloon-tipped catheter and the following measurements were obtained during hyperdynamic therapy: pulmonary artery wedge pressure, central venous pressure, cardiac index, stroke volume index, total peripheral resistance, and left ventricular stroke work index (LVSWI). Mean baseline cardiac function was found to be within normal limits (LVSWI = 47.6 ± 4.2 gm/min/sq m and cardiac index = 3.30 ± 0.22 liter/min/sq m). After baseline measurements were recorded, 5% albumin was infused at 300 cc/hr and dobutamine was initiated at a rate of 5 to 10 µg/kg/hr. This hyperdynamic therapy with dobutamine in the presence of volume loading resulted in a 52% increase in cardiac index, a 15% increase in LVSWI, and a 21% decrease in total peripheral resistance. The clinical reversal of ischemic symptoms due to subarachnoid hemorrhage was evident in 18 (78%) of the 23 patients.

Microcirculation and Macrocirculation in Hypertension: A Dangerous Cross-Link?

Hypertension ◽  
2022 ◽  
Author(s):  
Stephane Laurent ◽  
Claudia Agabiti-Rosei ◽  
Rosa Maria Bruno ◽  
Damiano Rizzoni
Keyword(s):  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Left Ventricular ◽  
Vicious Circle ◽  
Large Artery ◽  
Resistance Arteries ◽  
Cross Link ◽  
Small Artery ◽  
Structural Abnormalities ◽  
Small Resistance

Microcirculation and macrocirculation are tightly interconnected into a dangerous cross-link in hypertension. Small artery damage includes functional (vasoconstriction, impaired vasodilatation) and structural abnormalities (mostly inward eutrophic remodeling). These abnormalities are major determinants of the increase in total peripheral resistance and mean blood pressure (BP) in primary hypertension, which in the long term induces large artery stiffening. In turn, large artery stiffening increases central systolic and pulse pressures, which are further augmented by wave reflection in response to the structural alterations in small resistance arteries. Finally, transmission of high BP and flow pulsatility to small resistance arteries further induces functional and structural abnormalities, thus leading to increased total peripheral resistance and mean BP, thus perpetuating the vicious circle. Hyperpulsatility, in addition to higher mean BP, exaggerates cardiac, brain, and kidney damages and leads to cardiovascular, cerebral, and renal complications. The dangerous cross-link between micro and macrocirculation can be reversed into a virtuous one by ACE (angiotensin-converting enzyme) inhibitors, sartans, and calcium channel blockers. These three pharmacological classes are more potent than β-blockers and diuretics for reducing arterial stiffness and small artery remodeling. The same ranking was observed for their effectiveness at reducing left ventricular hypertrophy, preserving glomerular filtration rate, and preventing dementia, suggesting that they can act beyond brachial BP reduction, by breaking the micro/macrocirculation vicious circle.

Sign in / Sign up

Export Citation Format

Share Document