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Updated: Aug 21, 2026

Closure of a Patent Foramen Ovale (PFO): An Intervention Sequence
Published on: December 23, 2022
Mobility of the Septum primum does not depend on the foramen ovale diameter in normal fetuses
Paulo Zielinsky1, Marcelo Sallum, Fabíola Satler
1Instituto de Cardiologia do Rio Grande do Sul, Fundação Universitária de Cardiologia, Porto Alegre, RS, Brazil. pesquisa@cardnet.tche.br
Objective:
To test the hypothesis that a correlation exists between the maximum foramen ovale diastolic diameter and the excursion index (EI) of the septum primum in normal fetuses.
Methods:
One hundred and two normal fetuses with gestational ages ranging from 20 to 40 weeks were submitted to echocardiography. The foramen ovale diameter and the "maximal excursion" of the septum primum were measured in a 4-chamber view. The data were analyzed by Pearson's correlation coefficient.
Results:
The mean foramen ovale (FO) diameter was 5.06 +/- 1.29 mm; the maximal excursion of the septum primum was 5.42 +/- 1.41 mm; the left atrium diameter 11.47 +/- 2.76 mm; the septum primum "excursion index" was 0.48 +/- 0.09. Mean FO/EI ratio was 11.35 +/- 3.94 mm. No FO/EI correlation (r = -0.03) existed, and a weak foramen ovale/left atrium correlation (r = 0.31) was observed, as well as a weak foramen ovale/excursion of septum primum correlation (r = 0.21).
Conclusion:
Septum primum mobility does not depend on the foramen ovale diameter in normal fetuses, suggesting that the modifications of its diastolic displacement is not influenced by the size of the interatrial opening.
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