Transoesophageal echocardiography in the diagnosis of paradoxical embolism.

Two patients with systemic embolism were studied with transoesophageal contrast echocardiography which demonstrated its probable paradoxical nature. In both cases paradoxical embolism was associated with pulmonary embolism. Precordial contrast echocardiography demonstrated a right-to-left shunt in one patient but was unable to demonstrate a shunt in the second. Transoesophageal echocardiography suggested that the shunt was across a patent foramen oval in both cases and revealed large thrombi in the pulmonary arteries in one. When precordial contrast echocardiography reveals a right-to-left shunt or when it is technically inadequate in patients suspected of having one, transoesophageal contrast echocardiography can demonstrate the nature of the shunt and is an alternative to cardiac catheterisation techniques. In addition, it can reveal large thrombi in the pulmonary arteries.