scholarly journals Environmentally persistent free radicals decrease cardiac function and increase pulmonary artery pressure

2012 ◽  
Vol 303 (9) ◽  
pp. H1135-H1142 ◽  
Author(s):  
Sarah Mahne ◽  
Gin C. Chuang ◽  
Edward Pankey ◽  
Lucy Kiruri ◽  
Philip J. Kadowitz ◽  
...  
Keyword(s):  
Free Radicals ◽  
Left Ventricle ◽  
Cardiac Function ◽  
Left Ventricular Function ◽  
Ventricular Function ◽  
Diastolic Pressure ◽  
Silica Particles ◽  
Left Ventricular ◽  
Heme Oxygenase 1 ◽  
Stroke Work

Epidemiological studies have consistently linked inhalation of particulate matter (PM) to increased cardiac morbidity and mortality, especially in at risk populations. However, few studies have examined the effect of PM on baseline cardiac function in otherwise healthy individuals. In addition, airborne PM contain environmentally persistent free radicals (EPFR) capable of redox cycling in biological systems. The purpose of this study was to determine whether nose-only inhalation of EPFRs (20 min/day for 7 days) could decrease baseline left ventricular function in healthy male Sprague-Dawley rats. The model EPFR tested was 1,2-dichlorobenzene chemisorbed to 0.2-μm-diameter silica/CuO particles at 230°C (DCB230). Inhalation of vehicle or silica particles served as controls. Twenty-four hours after the last exposure, rats were anesthetized (isoflurane) and ventilated (3 l/min), and left ventricular function was assessed using pressure-volume catheters. Compared with controls, inhalation of DCB230 significantly decreased baseline stroke volume, cardiac output, and stroke work. End-diastolic volume and end-diastolic pressure were also significantly reduced; however, ventricular contractility and relaxation were not changed. DCB230 also significantly increased pulmonary arterial pressure and produced hyperplasia in small pulmonary arteries. Plasma levels of C-reactive protein were significantly increased by exposure to DCB230, as were levels of heme oxygenase-1 and SOD2 in the left ventricle. Together, these data show that inhalation of EPFRs, but not silica particles, decreases baseline cardiac function in healthy rats by decreasing cardiac filling, secondary to increased pulmonary resistance. These EPFRs also produced systemic inflammation and increased oxidative stress markers in the left ventricle.

INFLUENCE OF ACIDEMIA ON LEFT VENTRICULAR FUNCTION IN THE NEWBORN LAMB

PEDIATRICS ◽  
1966 ◽  
Vol 38 (3) ◽  
pp. 457-464
Author(s):  
Norman S. Talner ◽  
Thomas H. Gardner ◽  
S. Evans Downing
Keyword(s):  
Left Ventricle ◽  
Left Ventricular Function ◽  
Ventricular Function ◽  
Diastolic Pressure ◽  
Aortic Pressure ◽  
Left Ventricular ◽  
Newborn Lamb ◽  
Precise Control ◽  
Significant Impairment ◽  
Ph Range

The performance of the left ventricle in 20 newborn lambs was examined in a preparation which allowed precise control of aortic pressure, cardiac output, heart rate, and temperature. Reduction of arterial pH from a normal range (7.35 to 7.5) to severe acidemia (6.8 to 7.0) by hydrochloric or lactic acid infusion resulted in no significant impairment of left ventricular function. Prolonged acidemia (over 2 hours) failed to produce a reduction in left ventricular stroke volume or mean ejection rate for a given left ventricular end-diastolic pressure. Responsiveness of the left ventricle of the lamb to catecholamine stimulation was not diminished over the pH range 7.5 to 6.8. Under conditions of these investigations the apparent resistance of the myocardium of the newborn lamb, as well as the adult cat, to wide variations in pH may reflect a buffering capacity of cardiac muscle which would allow minimal change in intracellular pH, even though extracellular pH may indicate the presence of severe metabolic acidosis.

Effect of positive end-expiratory pressure on ventricular function in dogs

1979 ◽  
Vol 236 (4) ◽  
pp. H534-H544 ◽  
Author(s):  
R. M. Prewitt ◽  
L. D. Wood
Keyword(s):  
Cardiac Output ◽  
Left Ventricular Function ◽  
Pulmonary Edema ◽  
Ventricular Function ◽  
Diastolic Pressure ◽  
Intrathoracic Pressure ◽  
Esophageal Pressure ◽  
Left Ventricular ◽  
Stroke Work ◽  
Positive End Expiratory Pressure

Artificial ventilation with positive end-expiratory pressure (PEEP) reduces venous return by raising intrathoracic pressure. To determine whether PEEP decreases cardiac output further by depressing myocardial function, we constructed Starling curves, using rapid dextran infusion in 7 anesthetized dogs ventilated with zero (ZEEP) and 20 cm PEEP. The changes in stroke volume and in left ventricular stroke work (LVSW) when PEEP was added or removed were significantly greater than could be attributed to the corresponding change in transmural left ventricular end-diastolic pressure (LVEDPTM) on these Starling curves. To the extent that PEEP did not alter left ventricular diastolic volume-pressure characteristics, these data indicated PEEP depressed ventricular function. Identical changes with PEEP in cardiac output (-30%), esophageal pressure (+10 cmH2O), and left ventricular function were observed after pulmonary edema was induced with oleic acid. These results confirm and extend recent suggestions that high levels of PEEP depress left ventricular function in dogs, accounting for about half of the reduction in cardiac output before and during acute pulmonary edema.

scholarly journals Left ventricular end-diastolic pressure in evaluating left ventricular function

1981 ◽  
Vol 4 (1) ◽  
pp. 28-33 ◽  
Author(s):  
A. S. Iskandrian ◽  
B. L. Segal ◽  
A. Hamid HAKKI
Keyword(s):  
Left Ventricular Function ◽  
Ventricular Function ◽  
Diastolic Pressure ◽  
Left Ventricular

Ventricular function in the newborn lamb

1965 ◽  
Vol 208 (5) ◽  
pp. 931-937 ◽  
Author(s):  
S. Evans Downing ◽  
Norman S. Talner ◽  
Thomas H. Gardner
Keyword(s):  
Ventricular Function ◽  
Diastolic Pressure ◽  
Systemic Arterial Pressure ◽  
Left Ventricular ◽  
Stroke Work ◽  
Ventricular Mechanics ◽  
Inotropic State ◽  
Ejection Rate ◽  
Norepinephrine Infusion

The present study was initiated with the objective of evaluating in the newborn those aspects of ventricular mechanics which form the basis of the Frank-Starling relation, and which permit a determination of changes in the inotropic state of the heart. Left ventricular function was studied in lambs, 12 hr to 5 days old, utilizing a preparation designed to permit control and measurement of systemic arterial pressure (AP), cardiac output, heart rate (HR), and temperature. Continuous measurements of arterial Po2 and pH were made. These data permitted the construction of ventricular function curves relating stroke volume, mean ejection rate, and stroke work and power to left ventricular end-diastolic pressure, at constant AP and HR. In all preparations the Frank-Starling relation was found to be operative. Norepinephrine infusion, 1–2 µg/kg per min, resulted in a substantial increment of both force and speed parameters, thereby demonstrating the ability of the newborn heart to alter its inotropic state. Severe metabolic acidosis did not inhibit the response of the myocardium to norepinephrine.

Preservation of left ventricular function by insulin in experimental catecholamine cardiomyopathy

1980 ◽  
Vol 238 (2) ◽  
pp. H257-H262
Author(s):  
J. C. Werner ◽  
J. C. Lee ◽  
S. E. Downing
Keyword(s):  
Left Ventricular Function ◽  
Ventricular Function ◽  
Myocardial Injury ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Initial Slope ◽  
Histological Findings ◽  
Aortic Constriction ◽  
The Mean ◽  
Lv Volume

We have shown previously that insulin reduces myocardial injury associated with norepinephrine (NE) infusion in the rabbit (Am. J. Pathol. 93:399--353, 1978). In the present study, left ventricular function (LVF) was assessed from afterload curves obtained by progressive aortic constriction 2--4 days following NE infusion. The initial slope of the function curves (SFC), maximum dP/dt and left ventricular end-diastolic pressure at 120 mmHg ((LVEDP120) were used for comparison. In 4 controls, SFC averaged 23.8 mmHg/cmH2O. In 10 rabbits given NE, the mean slope was 8.4 (P less than 0.01). However, animals pretreated with insulin before being given NE did not differ from controls (SFC, 19.7 mmHg/cmH2O). These performance data were supported by measurements of LVEDP120, which were 2.8, 12.3 and 3.1 cmH2O, respectively (P less than 0.05 and less than 0.02). In spite of the higher LVEDP, max dP/dt120 was significantly lower in the NE group than in the group given insulin. Histological findings and postmortem measurements of LV volume and mass were consistent with the observed differences in LVF. It is concluded that NE damage reduces LVF and this is largely prevented by pretreatment with insulin.

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