| Project/Area Number |
06454306
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Pediatrics
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| Research Institution | UNIVERSITY OF TOKYO |
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Principal Investigator |
YANAGISAWA Masayoshi University of Tokyo, Department of Pediatrics, Professor, 医学部・附属病院, 教授 (90049031)
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| Co-Investigator(Kenkyū-buntansha) |
SHIRAISHI Hirohiko Jichi Medical school, Department of Pediatrics, Associate Professor, 医学部, 助教授 (40187521)
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| Project Period (FY) |
1994 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥6,700,000 (Direct Cost: ¥6,700,000)
Fiscal Year 1996: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1995: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1994: ¥3,200,000 (Direct Cost: ¥3,200,000)
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| Keywords | supraventricular tachyarrhythmia / atrial flutter / fetal lamb / hydrops fetalis / brain circulation / cardiac output / atrial pacing / congestive heart failure / 胎児 / 不整脈 / 頻脈 / 不整胎 / 中心静脈圧 / ペースメーカー |
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| Research Abstract |
Sustained fetal supraventricular tachyarrhythmias have potent negative effect on prognosis. They lead to fetal death, if they were not treated in utero or after elective Caesarian section. Pathophysiology of fetal supraventricular tachyarrhythmias, however, have not been studied completely.
To determine the threshold of rapid atrial pacing to bring fetal circulatory failure, we made fetal supraventricular tachyarrhythmia model and measured central venous pressure, aortic pressure, and estimated the right and left ventricular output by ultrasound. And we have measured the carotid artery flow. We have paced the right atrium at 200/min, 300/min, 350/min, and 400/min and observed the fetal circulatory changes in fetal sheep.
The central venous pressure increased and the aortic pressure decreased when the right atrium was paced at 350/min or more. The right ventricular output decreased when the right atrium was paced at 300/min or more, however, the left ventricular output remained constant. The right ventricular output decreased in spite of increased central venous pressure, which should be brought by the decreased ventricular filling time or decreased right ventricular reserved function. Decreased right ventricular output is associated with decreased placental circulation which can lead fetal congestive heart failure or fetal death. On the other hand the fetal carotid artery flow did not decrease when the right atrium was paced at any rate. Thus the flow to the brain was preserved even though the combined fetal cardiac output is decreased.
In conclusion, first the fetal circulatory failure was brought when the right atrium was paced at 300/min or more, second the brain circulation is preserved even though the fetal right ventricular output is decreased by the rapid atrial pacing.
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