This hole is either a heart defect (atrial septal defect) or an enlarged natural opening (foramen ovale) that is supposed to close soon after birth.

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When Dr. Lillehei was putting these patches in the children to close the ventricaluar septal defect, there's a critical nerve that runs right along that hole, and it's invisible.

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Dr. Chaim Lotem said the hole, measuring 1 to 2 millimeters, is a minor birth defect found in 15 percent to 25 percent of people.

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