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

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.

2005 ◽  
Vol 99 (4) ◽  
pp. 1378-1383 ◽  
Author(s):  
Jason D. Gardner ◽  
Gregory L. Brower ◽  
Joseph S. Janicki

Previously, we demonstrated that intact female rats fed a standard rodent diet containing soybean products exhibit essentially no adverse left ventricular (LV) remodeling in response to aortocaval fistula-induced chronic volume overload. We hypothesized that phytoestrogenic compounds in the diet contributed to the female cardioprotection. To test this hypothesis, four groups of female rats were studied: sham-operated (Sham) and fistula (Fist) rats fed a diet with [P(+)] or without [P(−)] phytoestrogens. Eight weeks postfistula, systolic and diastolic cardiac function was assessed by using a blood-perfused, isolated heart preparation. High-phytoestrogen diet had no effect on body, heart, and lung weights, or cardiac function in Sham rats. Fistula groups developed LV hypertrophy, which was not reduced by dietary phytoestrogens [1,184 ± 229 mg Fist-P(−) and 1,079 ± 199 mg Fist-P(+) vs. 620 ± 47 mg for combined Sham groups, P < 0.05]. Unstressed LV volume increased in Fist-P(−) rats (428 ± 16 vs. 300 ± 14 μl Sham, P < 0.0001), but it was not different from Sham for Fist-P(+) animals (286 ± 17 μl). Fist-P(−) rats developed increased ventricular compliance (5.3 ± 0.8 vs. 2.3 ± 0.3 μl/mmHg Sham, P < 0.01), whereas Fist-P(+) rats had no change in compliance (2.8 ± 0.4 μl/mmHg). Intrinsic ventricular contractility was maintained in the Fist-P(+) rats, but it was reduced ( P < 0.001) in the Fist-P(−) rats [systolic pressure-volume slope: 1.04 ± 0.03, 0.60 ± 0.06, and 0.99 ± 0.08 mmHg/μl, for Fist-P(+), Fist-P(−), and Sham, respectively]. These data indicate that dietary phytoestrogens contribute significantly to female cardioprotection against volume overload-induced adverse ventricular remodeling and that studies evaluating gender differences in cardiovascular remodeling must consider the influence of dietary phytoestrogens.


2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Amr Abdel Aal ◽  
Housam M. Hassan ◽  
Dina Ezzeldin ◽  
Maiy El Sayed

Abstract Background Ventricular septal defect (VSD) is the most common congenital heart disease. In patients with large VSD, left side chambers are subjected to volume overload with subsequent chambers dilatation and eccentric left ventricular hypertrophy. Percutaneous closure of VSD has been shown to be an effective method with equal safety and efficacy when compared to surgery. The effect of VSD closure on LV remodeling has been mainly assessed in patients treated with surgery and to date published data remain scarce. Therefore, we aim to evaluate the effect of percutaneous VSD closure on different LV parameters. Results Seventeen patients (median age 6 years (IQR 4.75–8 years), 70.6% females) who underwent percutaneous VSD closure were enrolled in the study. Sixteen patients (94%) had perimembranous VSD, and one patient had muscular VSD. The procedure was successful in all patients with no major complications. Nit Occlud® Lê coil device was implanted in 16 patients (94%), and one patient received Amplatzer PDA duct occlude device. At 6-months follow-up, there was a significant reduction in indexed LV dimensions [LVEDD/BSA (median 46.5 mm/m2 vs. 42.9 mm/m2, p = 0.03), LVESD/BSA (median 31.7 mm/m2 vs. 26.7 mm/m2, p = 0.02)], indexed LV volumes [LVEDV/BSA (median 52.6 ml/m2 vs. 37.3 ml/m2, p = 0.02), LVESV/BSA (median 31.7 ml/m2 vs. 23.3 ml/m2, p = 0.02)] and indexed LV mass (median 62.4 gm/m2 vs. 57.9 ml/m2, p = 0.01). There was a significant reduction in LVEDD Z-score (p = 0.01) and LVESD Z-score (p = 0.04). There was no significant change in LV EF. Conclusions Percutaneous VSD closure is associated with improvement of various LV parameters with consequential favorable LV remodeling and function.


2008 ◽  
Vol 294 (1) ◽  
pp. H198-H204 ◽  
Author(s):  
Jason D. Gardner ◽  
Gregory L. Brower ◽  
Tetyana G. Voloshenyuk ◽  
Joseph S. Janicki

Intact female rats fed a high-phytoestrogen diet are protected against adverse left ventricular (LV) remodeling induced by chronic volume overload. We hypothesized that both phytoestrogens and ovarian hormones, particularly estrogen, are necessary for this dietary-induced cardioprotection. To test this hypothesis, eight groups of female rats were studied; rats were fed either a high-phytoestrogen (+phyto) or phytoestrogen-free diet. Groups included sham-operated rats, intact rats with fistula (Fist), ovariectomized rats with fistula (Fist-OX), and Fist-OX rats treated with estrogen (EST). Myocardial function and remodeling were assessed after 8 wk of volume overload using a blood-perfused isolated heart apparatus. Fist-OX rats developed significant ventricular dilatation and increased compliance vs. intact Fist rats, which were associated with a significant decrease in contractility. Estrogen treatment prevented pulmonary edema and attenuated LV hypertrophy and dilatation but did not maintain contractility. However, dietary phytoestrogens completely prevented LV dilatation in both the Fist+phyto and Fist-OX+EST+phyto groups but had no effect on LV remodeling in the Fist-OX+phyto group. Contractility was significantly greater in the estrogen-treated rats fed the phytoestrogen diet than in those treated with estrogen alone. Dietary phytoestrogens did not affect LV or uterine mass, serum estrogen, LV estrogen receptor expression, or cardiac function in sham animals. These data indicate that estrogen is not solely responsible for the cardioprotection exhibited by intact females and that phytoestrogens can work synergistically with ovarian hormones to attenuate ventricular remodeling induced by chronic volume overload in female rats.


2001 ◽  
Vol 281 (5) ◽  
pp. H1938-H1945 ◽  
Author(s):  
Chari Y. T. Hart ◽  
John C. Burnett ◽  
Margaret M. Redfield

Anesthetic regimens commonly administered during studies that assess cardiac structure and function in mice are xylazine-ketamine (XK) and avertin (AV). While it is known that XK anesthesia produces more bradycardia in the mouse, the effects of XK and AV on cardiac function have not been compared. We anesthetized normal adult male Swiss Webster mice with XK or AV. Transthoracic echocardiography and closed-chest cardiac catheterization were performed to assess heart rate (HR), left ventricular (LV) dimensions at end diastole and end systole (LVDd and LVDs, respectively), fractional shortening (FS), LV end-diastolic pressure (LVEDP), the time constant of isovolumic relaxation (τ), and the first derivatives of LV pressure rise and fall (dP/d t max and dP/d t min, respectively). During echocardiography, HR was lower in XK than AV mice (250 ± 14 beats/min in XK vs. 453 ± 24 beats/min in AV, P < 0.05). Preload was increased in XK mice (LVDd: 4.1 ± 0.08 mm in XK vs. 3.8 ± 0.09 mm in AV, P < 0.05). FS, a load-dependent index of systolic function, was increased in XK mice (45 ± 1.2% in XK vs. 40 ± 0.8% in AV, P < 0.05). At LV catheterization, the difference in HR with AV (453 ± 24 beats/min) and XK (342 ± 30 beats/min, P < 0.05) anesthesia was more variable, and no significant differences in systolic or diastolic function were seen in the group as a whole. However, in XK mice with HR <300 beats/min, LVEDP was increased (28 ± 5 vs. 6.2 ± 2 mmHg in mice with HR >300 beats/min, P < 0.05), whereas systolic (LV dP/d t max: 4,402 ± 798 vs. 8,250 ± 415 mmHg/s in mice with HR >300 beats/min, P < 0.05) and diastolic (τ: 23 ± 2 vs. 14 ± 1 ms in mice with HR >300 beats/min, P < 0.05) function were impaired. Compared with AV, XK produces profound bradycardia with effects on loading conditions and ventricular function. The disparate findings at echocardiography and LV catheterization underscore the importance of comprehensive assessment of LV function in the mouse.


2001 ◽  
Vol 280 (2) ◽  
pp. H674-H683 ◽  
Author(s):  
Gregory L. Brower ◽  
Joseph S. Janicki

We previously reported an approximately 50% incidence of rats with symptoms of congestive heart failure (CHF) at 8 wk postinfrarenal aorto-caval fistula. However, it was not clear whether compensatory ventricular remodeling could continue beyond 8 wk or whether the remaining animals would have developed CHF or died. Therefore, the intent of this study was to complete the characterization of this model of sustained volume overload by determining the morbidity and mortality and the temporal response of left ventricular (LV) remodeling and function beyond 8 wk. The findings demonstrate an upper limit to LV hypertrophy and substantial increases in LV volume and compliance, matrix metalloproteinase activity, and collagen volume fraction associated with the development of CHF. There was an 80% incidence of morbidity and mortality following 21 wk of chronic volume overload. These findings indicate that the development of CHF is triggered by marked ventricular dilatation and increased compliance occurring once the myocardial hypertrophic response is exhausted.


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