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What is a Patent Foramen Ovale or PFO?

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PFO in heart

About 1 in 4 people have a hole in their heart called a PFO¹

Before birth, all babies have a hole in the heart called the foramen ovale. This hole allows babies to get blood and oxygen through the umbilical cord. The foramen ovale normally closes after birth. In about 25% of people, this hole doesn’t close all the way.¹ When the hole remains open, it’s called a patent foramen ovale, or a PFO.

The foramen ovale remains open post-birth

Open foramen ovale Before birth Open foramen ovale
Natural closure of the foramen ovale Post birth Natural closure of the foramen ovale
Foramen ovale remains open, creating a PFO Post birth Foramen ovale remains open, creating a PFO
  1. Kent DM, Thaler DE. Is patent foramen ovale a modifiable risk factor for stroke recurrence? Stroke. 2010;41(10 Suppl):S26-30. doi: 10.1161/STROKEAHA.110.595140
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