scholarly journals Influence of the pericardium on left ventricular end-diastolic pressure-segment relations during early and later stages of experimental chronic volume overload in dogs.

1982 ◽  
Vol 50 (4) ◽  
pp. 501-509 ◽  
Author(s):  
M M LeWinter ◽  
R Pavelec
Keyword(s):  
Diastolic Pressure ◽  
Volume Overload ◽  
Left Ventricular ◽  
Chronic Volume Overload

Temporal evaluation of left ventricular remodeling and function in rats with chronic volume overload

1996 ◽  
Vol 271 (5) ◽  
pp. H2071-H2078 ◽  
Author(s):  
G. L. Brower ◽  
J. R. Henegar ◽  
J. S. Janicki
Keyword(s):  
Ventricular Remodeling ◽  
Diastolic Pressure ◽  
Systolic Function ◽  
Left Ventricular Remodeling ◽  
Isolated Heart ◽  
Volume Overload ◽  
Left Ventricular ◽  
Control Value ◽  
Chronic Volume Overload ◽  
And Function

The left ventricle (LV) significantly dilates and hypertrophies in response to chronic volume overload. However, the temporal responses in LV mass, volume, and systolic/diastolic function secondary to chronic volume overload induced by an infrarenal arteriovenous (A-V) fistula in rats have not been well characterized. To this end, LV end-diastolic pressure, size, and function (i.e., isovolumetric pressure-volume relationships in the blood-perfused isolated heart) were assessed at 1, 2, 3, 5, and 8 wk post-A-V fistula and compared with age-matched control animals. Progressive hypertrophy (192% at 8 wk), ventricular dilatation (172% at 8 wk), and a decrease in ventricular stiffness (257% at 8 wk) occurred in the fistula groups. LV end-diastolic pressure increased from a control value of 4.2 +/- 3.1 mmHg to a peak value of 15.7 +/- 3.6 mmHg after 3 wk of volume overload. A subsequent decline in LVEDP to 11.0 +/- 6.0 mmHg together with further LV dilation (169%) corresponded to a significant decrease in LV stiffness (222%) at 5 wk post-A-V fistula. Myocardial contractility, as assessed by the isovolumetric pressure-volume relationship, was significantly reduced in all A-V fistula groups; however, the compensatory remodeling induced by 8 wk of chronic biventricular volume overload tended to preserve systolic function.

Apoptosis in the left ventricle of chronic volume overload causes endocardial endothelial dysfunction in rats

2002 ◽  
Vol 282 (4) ◽  
pp. H1197-H1205 ◽  
Author(s):  
Michael J. Cox ◽  
Harpreet S. Sood ◽  
Matthew J. Hunt ◽  
Derrick Chandler ◽  
Jeffrey R. Henegar ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blot Analysis ◽  
Diastolic Pressure ◽  
Volume Overload ◽  
Left Ventricular ◽  
Tissue Inhibitor Of Metalloproteinase ◽  
Heart Weight ◽  
Sprague Dawley ◽  
Lung Weight ◽  
Cardiac Relaxation

The hypothesis is that chronic increases in left ventricular (LV) load induce oxidative stress and latent matrix metalloproteinase (MMP) is activated, allowing the heart to dilate in the absence of endothelial nitric oxide (NO) and thereby reduce filling pressure. To create volume overload, an arteriovenous (A-V) fistula was placed in male Sprague-Dawley rats. To decrease oxidative stress and apoptosis, 0.08 mg/ml nicotinamide (Nic) was administered in drinking water 2 days before surgery. The rats were divided into the following groups: 1) A-V fistula, 2) A-V fistula + Nic, 3) sham operated, 4) sham + Nic, and 5) control (unoperated); n = 6 rats/group. After 4 wk, hemodynamic parameters were measured in anesthetized rats. The heart was removed and weighed, and LV tissue homogeneates were prepared. A-V fistula caused an increase in heart weight, lung weight, and end-diastolic pressure compared with the sham group. The levels of malondialdehyde (MDA; a marker of oxidative stress) was 6.60 ± 0.23 ng/mg protein and NO was 6.87 ± 1.21 nmol/l in the LV of A-V fistula rats by spectrophometry. Nic treatment increased NO to 13.88 ± 2.5 nmol/l and decreased MDA to 3.54 ± 0.34 ng/mg protein ( P= 0.005). Zymographic levels of MMP-2 were increased, as were protein levels of nitrotyrosine and collagen fragments by Western blot analysis. The inhibition of oxidative stress by Nic decreased nitrotyrosine content and MMP activity. The levels of tissue inhibitor of metalloproteinase-4 mRNA were decreased in A-V fistula rats and increased in A-V fistula rats treated with Nic by Northern blot analysis. TdT-mediated dUTP nick-end labeling-positive cells were increased in A-V fistula rats and decreased in fistula rats treated with Nic. Acetylcholine and nitroprusside responses in cardiac rings prepared from the above groups of rats suggest impaired endothelial-dependent cardiac relaxation. Treatment with Nic improves cardiac relaxation. The results suggest that an increase in the oxidative stress and generation of nitrotyrosine are, in part, responsible for the activation of metalloproteinase and decreased endocardial endothelial function in chronic LV volume overload.

Influence of the pericardium on left ventricular diastolic pressure-volume curves in dogs with sustained volume overload

1983 ◽  
Vol 105 (6) ◽  
pp. 995-1001 ◽  
Author(s):  
Valmik Bhargava ◽  
Ralph Shabetai ◽  
John Ross ◽  
Kunio Shirato ◽  
Richard S. Pavelec ◽  
...  
Keyword(s):  
Diastolic Pressure ◽  
Volume Overload ◽  
Left Ventricular

scholarly journals Modification of a Volume-Overload Heart Failure Model to Track Myocardial Remodeling and Device-Related Reverse Remodeling

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Egemen Tuzun ◽  
Roger Bick ◽  
Cihan Kadipasaoglu ◽  
Jeffrey L. Conger ◽  
Brian J. Poindexter ◽  
...  
Keyword(s):  
Heart Failure ◽  
Wall Thickness ◽  
Ventricular Remodeling ◽  
Diastolic Pressure ◽  
Volume Overload ◽  
Left Ventricular ◽  
Reverse Remodeling ◽  
Sheep Model ◽  
Dystrophin Expression ◽  
Cellular Markers

Purpose. To provide an ovine model of ventricular remodeling and reverse remodeling by creating congestive heart failure (CHF) and then treating it by implanting a left ventricular assist device (LVAD). Methods. We induced volume-overload heart failure in 2 sheep; 20 weeks later, we implanted an LVAD and assessed recovery 11 weeks thereafter. We examined changes in histologic and hemodynamic data and levels of cellular markers of CHF. Results. After CHF induction, we found increases in LV end-diastolic pressure, LV systolic and diastolic dimensions, wall thickness, left atrial diameter, and atrial natriuretic protein (ANP) and endothelin-1 (ET-1) levels; β-adrenergic receptor (BAR) and dystrophin expression decreased markedly. Biopsies confirmed LV remodeling. After LVAD support, LV systolic and diastolic dimensions, wall thickness, and mass, and ANP and ET-1 levels decreased. Histopathologic and hemodynamic markers improved, and BAR and dystrophin expression normalized. Conclusions. We describe a successful sheep model for ventricular and reverse remodeling.

Nonsympathetic increased inotropic state early after aortic insufficiency

1982 ◽  
Vol 242 (6) ◽  
pp. H973-H979
Author(s):  
B. Crozatier ◽  
D. Caillet ◽  
J. L. Chevrier ◽  
P. Y. Hatt
Keyword(s):  
Volume Overload ◽  
Wall Stress ◽  
Aortic Insufficiency ◽  
Left Ventricular ◽  
Beta Blockade ◽  
Internal Diameter ◽  
Inotropic State ◽  
Chronic Volume Overload ◽  
Before And After ◽  
Ventricular Response

The very early left ventricular response to chronic volume overload induced by aortic insufficiency (AI) was examined in conscious dogs previously instrumented with a left ventricular micromanometer and ultrasonic crystals measuring internal diameter, segmental length, and parietal wall thickness. Acute volume loading with dextran (AVL) was compared with that 24 and 48 h after AI induced by a perforation of the aortic valve. beta-Blockade was also produced before and after AI. For a similar increase in preload in AVL and after AI, the percent change in systolic shortening of diameters and segments (% delta L) increased from 30.4 to 34.1% after AI (P less than 0.01). For matched calculated wall stress during AVL and AI, % delta L and peak velocity of shortening were significantly increased after AI, and the same results were reproduced after beta-blockade. We conclude that, at the early phase of chronic volume overload before hypertrophy appears, left ventricular hyperfunction is mainly due to a nonsympathetic increased contractility and that, in the conscious dog, the inotropic state appears to be modified by a sustained increased preload.

Enhanced left ventricular shortening during chronic volume overload in conscious dogs

1980 ◽  
Vol 238 (2) ◽  
pp. H126-H133 ◽  
Author(s):  
M. M. LeWinter ◽  
R. L. Engler ◽  
J. S. Karliner
Keyword(s):  
Volume Overload ◽  
Left Ventricular ◽  
Conscious Dogs ◽  
Adrenergic Stimulation ◽  
Ventricular Performance ◽  
Blood Pressure Elevation ◽  
Chronic Volume Overload ◽  
Before And After ◽  
Ejection Phase

Prior work with the arteriovenous fistula model indicates that left ventricular performance is at least normal and may be enhanced during chronic volume overload. The present study was undertaken in conscious dogs to determine whether ejection-phase indices of ventricular function are enhanced after 1 mo of volume overload, using an experimental design in which loading conditions could be accounted for and animals were used as their own controls before and after volume overload. We also examined the response of the volume-overloaded left ventricle to an afterload stress and the role of adrenergic stimulation in maintenance of function. Both at rest and during hemodynamically matched conditions, percent shortening (ultrasonic dimension gauges) and mean shortening rates were increased during volume overload. This difference was maintained during phenylephrine-induced blood pressure elevation, although diastolic dimensions increased more in control studies during phenylephrine. Propranolol produced significantly larger reductions in these indices during volume overload than in the control state. Thus, ejection-phase function is enhanced during volume overload, at least in part due to increased adrenergic stimulation.

Left ventricular failure induced by myocardial infarction. I. Myocyte hypertrophy

1985 ◽  
Vol 248 (6) ◽  
pp. H876-H882 ◽  
Author(s):  
P. Anversa ◽  
A. V. Loud ◽  
V. Levicky ◽  
G. Guideri
Keyword(s):  
Myocardial Infarction ◽  
Diastolic Pressure ◽  
Pressure Overload ◽  
Volume Overload ◽  
Left Ventricular Pressure ◽  
Systolic Arterial Pressure ◽  
Left Ventricular ◽  
Cellular Growth ◽  
Left Ventricular Failure ◽  
Ventricular Failure

To determine whether left ventricular failure after acute myocardial infarction is associated with a growth response of the myocytes that tends to compensate for the loss of muscle mass and function, the left coronary artery in rats was ligated near its origin, and the animals were killed 3 days later. Elevated left ventricular end-diastolic pressure and decreased first derivative of left ventricular pressure and systolic arterial pressure indicated significant impairment of ventricular function. Absolute infarct size, determined morphometrically by measurement of the fraction of myocyte nuclei lost, averaged 57%. Hypertrophy of surviving left ventricular myocytes was 28%, involving a 14% increase in cell length and a 6% increase in diameter. Right ventricular myocyte volume per nucleus increased 21% by a 10% enlargement of cellular diameter with no change in length. These results show on a cellular basis that myocardial hypertrophy in the left ventricle is accomplished by cellular shape changes characteristic of a combination of pressure and volume overload hypertrophy, whereas cellular growth in the right ventricle is consistent with pressure overload hypertrophy.

Captopril reduces left ventricular enlargement induced by chronic volume overload

1990 ◽  
Vol 259 (3) ◽  
pp. H796-H803
Author(s):  
R. G. Gay
Keyword(s):  
Pulse Pressure ◽  
Diastolic Pressure ◽  
Ex Vivo ◽  
Volume Overload ◽  
Wall Stress ◽  
Left Ventricular ◽  
Aortic Occlusion ◽  
End Diastolic Volume ◽  
Volume Relation ◽  
Captopril Treatment

The effect of captopril treatment on left ventricular (LV) function, mass, and volume during chronic volume overload induced by production of aortic insufficiency (AI) was studied. AI was caused by mechanical disruption of the aortic valve in 175- to 225-g male Sprague-Dawley rats. At 24 h after surgery, AI and sham-operated rats were divided into control and captopril treatment (2 g/l drinking water) groups. After 2 mo of treatment, hemodynamics were measured in open-chest rats, and the LV pressure-volume relation was determined ex vivo. Compared with sham-operated rats, in the untreated AI rats, aortic pulse pressure was increased nearly 100%, LV end-diastolic pressure was 10 +/- 1 vs 3 +/- 1 mmHg, and LV end-diastolic volume was 1.25 +/- 0.07 vs 0.36 +/- 0.03 ml. LV weight was increased 43% and the LV pressure-volume relation was shifted rightward by AI. LV systolic and diastolic wall stress were increased in rats with AI. Peak LV pressure during aortic occlusion was decreased in AI rats, however, peak wall stress during aortic occlusion was not different compared with sham-operated rats. Captopril treatment decreased aortic pulse pressure and LV systolic pressure. Both LV weight and LV end-diastolic volume measured from the ex vivo pressure-volume relation at LV end-diastolic pressure were increased by 33% in untreated AI rats compared with captopril-treated AI rats. Captopril treatment of AI rats shifted the LV pressure-volume to the left compared with untreated rats. LV pressure and wall stress during aortic occlusion were not changed in captopril-treated AI rats.(ABSTRACT TRUNCATED AT 250 WORDS)

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