Paradoxical brain embolism caused by an arterial−venous fistula: a diagnostic pitfall

The transesophageal echocardiography (TEE) and contrast-enhanced transcranial Doppler/Duplex ultrasonography (ceTCD) are complementary methods for diagnosing a right to left shunt across a patent foramen ovale. We report on a case of paradoxical embolism across a subclavian arterial–venous fistula. This case underlines the necessity of performing the ceTCD, as in this condition the right to left shunt could be detected by means of ceTCD, whereas the TEE reveals regular findings.