The quest for the identification of pathogenic patent foramen ovale.

Patent foramen ovale (PFO) causing right-to-left shunt (RLS) has been demonstrated to be an important condition present in patients with ischemic strokes without other underlying predisposing factors. It constitutes 95% of RLS, being the rest pulmonary arteriovenous fistulae and other defects of the auricular septum. In healthy subjects, PFO is found in 24.2% of autopsies, 23.7% of contrast-enhanced transesophageal echocardiogram (cTEE), 31.3% of contrast-enhanced transcranial Doppler (cTCD), and 14.7% of contrast-enhanced transthoracic echocardiogram (cTTE). These percentages are higher in cryptogenic [...]