Aquarium sign in the left atrium.

A 50-year-old man presented with fever and chest pain. Later on the same day, he developed ischemic stroke and deteriorated into loss of consciousness. A trans-thoracic echocardiography showed air bubbles in the left atrium, resembling the floating bubbles in an aquarium. After further workups, atrio-esophageal fistula was diagnosed. To the best of our knowledge visualization of atrio-esophageal fistula by echocardiography has never been described previously. 2007 S. Karger AG, Basel