Performance characteristics of the right heart bypass preparation

1960 ◽  
Vol 198 (3) ◽  
pp. 552-560 ◽  
Author(s):  
Fred S. Grodins ◽  
William H. Stuart ◽  
Rodney L. Veenstra
Keyword(s):  
Venous Pressure ◽  
Self Regulation ◽  
Degree Of Approximation ◽  
Linear Functions ◽  
Regression Equations ◽  
Right Heart ◽  
Pump Output ◽  
Steady State Responses ◽  
The Right ◽  
Positive Functions

In eight dogs under morphine-barbital anesthesia, the right ventricle was replaced by a sigmamotor pump in order to study steady-state responses of circuit pressures to arbitrary variations in ‘right heart’ output. In the systemic circuit, it was found that arterial pressure (PAS, mm Hg) was a positive and venous pressure (PVS, mm Hg) a negative function of pump output (Q, cc/min). In the pulmonary circuit, both arterial (PAP) and left atrial (PLA) pressures were positive functions of pump output. Despite considerable variations in detail between animals, individual animal pressure-flow curves could all be represented to a reasonable degree of approximation by linear functions within the range of the data. Average regression equations for the eight animals were: PAS = 18.3 + 0.0639Q, PVS = 20.2 – 0.0124Q, (PAS – PVS) = 0.0756Q – 1.59 PAP = 11.2 + 0.0151Q, PLA = 7.0 + 0.00208Q, and (PAP – PLA) - 3.9 + 0.0154Q. These results were interpreted in terms of a quantitative theory of mechanical self-regulation in the cardiovascular system.

Effects of venous pressure on coronary circulation and intramyocardial fluid mechanics

1994 ◽  
Vol 267 (3) ◽  
pp. H1002-H1009 ◽  
Author(s):  
I. Izrailtyan ◽  
H. F. Frasch ◽  
J. Y. Kresh
Keyword(s):  
Coronary Flow ◽  
Coronary Circulation ◽  
Venous Pressure ◽  
Rabbit Heart ◽  
Coronary Perfusion Pressure ◽  
Coronary Perfusion ◽  
Right Heart ◽  
Tissue Pressure ◽  
Parallel Shift ◽  
The Right

This investigation examined the interaction between right heart pressure (RHP), coronary perfusion pressure (CPP), intramyocardial tissue pressure (IMP), and coronary flow mechanics, including partitioning of coronary effluent in the isolated Krebs-Henseleit perfused rabbit heart. The major new finding was a parallel shift in the IMP-inflow relationship to a higher tissue pressure level in response to an increase in RHP. Accompanying the rise in RHP from 0 to 15 and 25 mmHg, IMP at zero coronary inflow in the beating (and arrested) heart increased from 5.8 +/- 1.0 (7.7 +/- 1.2) to 16.3 +/- 1.2 (17.9 +/- 1.3) and 28.6 +/- 1.7 (26.4 +/- 2.0) mmHg, respectively. A concomitant parallel shift in the CPP-inflow relation to higher pressures was consistently observed. The fraction of total coronary flow drained by the right heart was not constant. A higher partition of coronary outflow to the left heart (7.8 +/- 3.8, 34.3 +/- 3.0, and 47.9 +/- 4.3%, respectively) accompanied the increase in RHP. Intramyocardial partitioning of coronary outflow pathways mediates the effects of venous pressure modulation on coronary circulation. The interaction between coronary venous pressure and the extravascular environment modifies the effective back pressure to arterial inflow.

Left ventricular mechanics in arrested dog heart: effects of ventricular interaction and vascular volumes

1995 ◽  
Vol 268 (5) ◽  
pp. H2125-H2132 ◽  
Author(s):  
D. Manor ◽  
S. Williams ◽  
R. Ator ◽  
K. Bryant ◽  
K. W. Scheel
Keyword(s):  
Coronary Sinus ◽  
Venous Pressure ◽  
Left Ventricular ◽  
Vasomotor Tone ◽  
Right Heart ◽  
Ventricular Mechanics ◽  
Relative Contribution ◽  
Left Ventricular Mechanics ◽  
Lv Volume ◽  
The Right

The present study was designed to determine the effects of right heart pressure on the compliance of the left ventricle (LV). The studies were conducted on isolated, blood-perfused, potassium-arrested dog hearts with vasomotor tone either present (n = 5) or absent (n = 8). A balloon was used to control LV volume, whereas right heart (RHP) or coronary sinus (CSP) pressures were controlled via a column placed in the right heart or coronary sinus, respectively. Control of CSP independently of RHP allowed us to assess the relative contribution of coronary venous pressure to changes in LV compliance under conditions of elevated RHP. LV volume and compliance at a LV pressure of 15 mmHg (V15 and C15, respectively) were calculated to quantify the shift and slope changes of the LV pressure-volume (P-V) relationships. V15 and C15 decreased with vasomotor tone present from 52.8 +/- 1.4 ml and 1.7 +/- 0.1 ml/mmHg at control, to 43.3 +/- 2.1 ml and 1.4 +/- 0.1 ml/mmHg (P < 0.05) with RHP = 0 and 20 mmHg, respectively. Similar effects were obtained with vasodilation, but C15 was significantly lower relative to autoregulation but C15 was significantly lower relative to autoregulation (1.0 +/- 0.1 at control RHP, P < 0.05). Elevation of CSP with vasomotor tone resulted in an upward shift in the LV P-V relationship: V15 decreased from 53.4 +/- 2.1 at CSP = 0 mmHg to 50.9 +/- 1.6 ml at CSP = 20 mmHg (P < 0.05). After vasodilation there was no detectable shift in the LV P-V relationship with elevation of CSP.

Mechanism of the cardiac output reduction by hexamethonium

1960 ◽  
Vol 199 (2) ◽  
pp. 319-324 ◽  
Author(s):  
B. G. Zimmerman ◽  
M. J. Brody ◽  
L. Beck
Keyword(s):  
Cardiac Output ◽  
Low Dose ◽  
Venous Pressure ◽  
Right Heart ◽  
Blocking Agents ◽  
Significant Depression ◽  
Cardiac Filling ◽  
The Right ◽  
Ganglionic Blocking ◽  
Pressure Stabilizer

The action of ganglionic blocking agents on the cardiac output has been studied in intact, closed-chested animals whose cardiac filling pressure was maintained constant by means of a pressure-stabilizer operating through a jugular catheter introduced into the right heart. Under these conditions cardiodynamic consequences of venous pooling are negated. Hexamethonium produces a fall in cardiac output and blood pressure comparable to that observed in animals without controlled venous pressure. In cardiac sympathectomized animals the cardiac output increases slightly following the administration of hexamethonium. These observations indicate that the ganglion blocking agents reduce cardiac output primarily by blocking tonic sympathetic activity to the heart. The decrease in cardiac output is brought about by a reduction in both stroke volume and heart rate. Sympathetic tone to the blood vessels is reduced by a low dose of hexamethonium before a significant depression in cardiac output occurs.

Early Predictive Biochemical, Electrocardiographic and Echocardiographic Markers for Cardiac Damage in Patients with Pulmonic Silicosis

2019 ◽  
Vol 70 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Venera Cristina Dinescu ◽  
Ileana Puiu ◽  
Sorin Nicolae Dinescu ◽  
Diana Rodica Tudorascu ◽  
Elena Catalina Bica ◽  
...  
Keyword(s):  
Heart Disease ◽  
Right Ventricle ◽  
Control Group ◽  
Cardiac Damage ◽  
Right Heart ◽  
Pulmonary Heart Disease ◽  
Upper Limit ◽  
Echocardiographic Parameters ◽  
The Right ◽  
Chronic Pulmonary Heart Disease

The aim of this study was to identify correlations between electrocardiographic and echocardiographic changes in patients with silicosis prior to the occurrence of chronic pulmonary heart disease. We conducted a prospective, descriptive, analytical study, in which we included a group of 67 patients consecutively admitted to the Health Promotion and Occupational Medicine Clinic between December 2016 and January 2018, aged 47 to 78 years.There was a biochemical and electrocardiographic evaluation for each patient as well as a right ventricle echocardiographic evaluation (diameters, volumes, function). A control group, including 25 patients with benign minor diseases that required a cardiologist consultation, was also used. From the electrocardiographic point of view, slight changes were observed regarding the waves of electrical activity of the right ventricle. Taking into account the degree of ventilatory dysfunction (depending on FEV1), changes in right heart echocardiographic parameters were identified. Thus, in what the most important right ventricular parameters, including the tricuspid annular plane systolic excursion (TAPSE) or the RV index of myocardial performance (RVMPI) were concerned, values at the upper limit of normality were recorded in most patients with moderate and severe ventilatory dysfunction. Values of echocardiographic parameters of the right heart at the upper limit of normality, correlated with the degree of ventilatory dysfunction, are early markers for cardiovascular damage in patients with pulmonary silicosis prior to the occurrence of chronic pulmonary heart disease also known ascor pulmonale.

Self-Regulation and Human Progress

2018 ◽  
Author(s):  
Evan Osborne
Keyword(s):  
Scientific Method ◽  
Mutual Influence ◽  
Free Market ◽  
Self Regulation ◽  
Free Expression ◽  
Trial And Error ◽  
Human History ◽  
Economic Context ◽  
The Right ◽  
First Time

Does humanity progress primarily through leaders organizing and directing followers, or through trial and error by individuals free to chart their own path? For most of human history ruling classes had the capacity and the desire to tightly regiment society, to the general detriment of progress. But beginning in the 1500s, Europeans developed a series of arguments for simply leaving well enough alone. First in the form of the scientific method, then in the form of free expression, and finally in the form of the continuously, spontaneously reordered free market, people began to accept that progress is hard, and requires that an immense number of mistakes be tolerated so that we may learn from them. This book tells the story of the development of these three ideas, and for the first time tells of the mutual influence among them. It outlines the rise, and dramatic triumph, of each of these self-regulating systems, followed by a surprising rise in skepticism, especially in the economic context. Such skepticism in the 20th century was frequently costly and sometimes catastrophic. Under the right conditions, which are more frequent than generally believed, self-regulating systems in which participants organize themselves are superior. We should accept their turbulence in exchange for the immense progress they generate.

scholarly journals Right Heart Structure, Geometry and Function Assessed by Echocardiography in 6-Year-Old Children Born Extremely Preterm—A Population-Based Cohort Study

2020 ◽  
Vol 10 (1) ◽  
pp. 122
Author(s):  
Lilly-Ann Mohlkert ◽  
Jenny Hallberg ◽  
Olof Broberg ◽  
Gunnar Sjöberg ◽  
Annika Rydberg ◽  
...  
Keyword(s):  
Preterm Birth ◽  
Ductus Arteriosus ◽  
Population Based ◽  
Right Heart ◽  
Functional Changes ◽  
Cardiac Phenotype ◽  
Extremely Preterm ◽  
Healthy Control ◽  
The Right ◽  
And Function

Preterm birth has been associated with altered cardiac phenotype in adults. Our aim was to test the hypothesis that children surviving extremely preterm birth have important structural or functional changes of the right heart or pulmonary circulation. We also examined relations between birth size, gestational age, neonatal diagnoses of bronchopulmonary dysplasia (BPD) and patent ductus arteriosus (PDA) with cardiac outcomes. We assessed a population-based cohort of children born in Sweden before 27 weeks of gestation with echocardiography at 6.5 years of age (n = 176). Each preterm child was matched to a healthy control child born at term. Children born preterm had significantly smaller right atria, right ventricles with smaller widths, higher relative wall thickness and higher estimated pulmonary vascular resistance (PVR) than controls. In preterm children, PVR and right ventricular myocardial performance index (RVmpi’) were significantly higher in those with a PDA as neonates than in those without PDA, but no such associations were found with BPD. In conclusion, children born extremely preterm exhibit higher estimated PVR, altered right heart structure and function compared with children born at term.

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