卵圆孔在胎儿期作为生理通道,接受来自胎盘的动脉血,经脐静脉进入胎儿体内,从右心房流入左心房,以维持胎儿血液循环。出生后,随着呼吸建立,肺循环压力下降,左心房压力增高,使卵圆孔生理性关闭。但仍有约25%的2岁儿童卵圆孔未闭,若>3岁卵圆孔仍未闭合,称为卵圆孔未闭(patent foramen ovale,PFO)[1]。尸检研究发现,PFO发生率 Foramen ovale in the fetus as a physiological channel, receiving blood from the placenta, the umbilical vein into the fetus through the right atrium into the left atrium to maintain fetal blood circulation. After birth, with the establishment of respiration, decreased pulmonary pressure, left atrial pressure increased, so that the foramen ovale physiologically closed. However, about 25% of 2-year-old children still have patent foramen ovale. If the foramen ovale is still not closed at> 3 years, it is called patent foramen ovale (PFO) [1]. Autopsy study found that the incidence of PFO