Intracardiac platypnea-orthodeoxia syndrome diagnosed by forward-bending and abdominal compression

Intracardiac platypnea-orthodeoxia syndrome (POS) is a pathological condition that leads to a reduction in oxygenation in the sitting position. The detection rate of patent foramen ovale that causes POS increases with Valsalva manoeuvre and cough. We report the case of a 92-year-old woman with POS, which could not be diagnosed in the sitting position. The Valsalva manoeuvre could not be performed because of dementia, and POS was diagnosed on the forward-bending position and abdominal compression. It was assumed that forward-bending increases the right atrial pressure by compressing the right ventricle along with elongation of the aorta, and abdominal compression increases the shunt volume by increasing the venous return. If POS is suspected in patients with dementia which cannot be diagnosed in the sitting position, forward-bending and abdominal compression, instead of the Valsalva manoeuvre, might be useful.