Abstract:
:Fetal ventricular performance has been considered limited because ventricular output does not increase with rapid volume expansion above mean left atrial pressures (mLAPs) of 5-7 mm Hg. To explore relations between preload, afterload, and stroke volume (SV) in the fetal left ventricle, we instrumented 126-129 days gestation fetal lambs with ascending aortic electromagnetic flow transducers, vascular catheters, and inflatable occluders around the aortic isthmus (n = 8) or descending aorta (n = 7). At 24-48 hours after surgery, blood was withdrawn or infused to reach various mLAPs. The aorta was then slowly occluded as aortic flow and mean arterial pressure (MAP) were measured continuously. Isthmus constriction produced linear decreases in SV as MAP increased; mLAP was unchanged. Descending aortic constriction produced no decrease in SV until high MAPs were reached. SV decreased as MAP increased further, and mLAP rose significantly. The curve relating mLAP and SV before constriction showed little increase in SV above mLAPs of 5-7 mm Hg; however, when curves were derived relating SV and mLAP at relatively constant MAPs, SV continued to increase even above an mLAP of 8-10 mm Hg. Our studies indicate that the fetal left ventricle responds to progressive increases in mLAP to at least 10 mm Hg. The lack of increase in SV above an mLAP of 5-7 mm Hg with rapid volume expansion is related to the concomitant increase in MAP and afterload.
journal_name
Circ Resjournal_title
Circulation researchauthors
Hawkins J,Van Hare GF,Schmidt KG,Rudolph AMdoi
10.1161/01.res.65.1.127subject
Has Abstractpub_date
1989-07-01 00:00:00pages
127-34issue
1eissn
0009-7330issn
1524-4571journal_volume
65pub_type
杂志文章abstract::The effects of endothelin on systemic and renal hemodynamics in anesthetized spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats were examined. Endothelin (500 ng i.v. +1,000 ng/hr per 300-g rat) elevated mean blood pressure by 13% (p less than 0.02) and decreased renal blood flow by 71% and glomerular filtrat...
journal_title:Circulation research
pub_type: 杂志文章
doi:10.1161/01.res.65.5.1370
更新日期:1989-11-01 00:00:00
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更新日期:1996-05-01 00:00:00
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pub_type: 杂志文章
doi:10.1161/01.res.77.5.869
更新日期:1995-11-01 00:00:00
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更新日期:1998-06-15 00:00:00
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pub_type: 杂志文章
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pub_type: 杂志文章,评审
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更新日期:2013-08-30 00:00:00
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更新日期:2006-02-17 00:00:00
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更新日期:1982-03-01 00:00:00
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pub_type: 杂志文章
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更新日期:1991-12-01 00:00:00
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doi:10.1161/CIRCRESAHA.113.300350
更新日期:2013-03-15 00:00:00
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journal_title:Circulation research
pub_type: 杂志文章
doi:10.1161/01.RES.0000264081.78659.45
更新日期:2007-04-13 00:00:00
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pub_type: 杂志文章
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更新日期:2004-06-25 00:00:00
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pub_type: 杂志文章
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更新日期:1991-05-01 00:00:00
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更新日期:1994-04-01 00:00:00
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更新日期:1988-06-01 00:00:00
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pub_type: 杂志文章
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更新日期:2003-05-16 00:00:00
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pub_type: 杂志文章
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更新日期:1976-10-01 00:00:00
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pub_type: 杂志文章
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更新日期:1996-04-01 00:00:00
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更新日期:2016-03-18 00:00:00
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pub_type: 杂志文章
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更新日期:1992-10-01 00:00:00
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更新日期:2004-04-16 00:00:00
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更新日期:1997-01-01 00:00:00
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更新日期:1993-08-01 00:00:00