A case of a 43-year-old man with impending paradoxical embolism (IPE) is described. The patient initially presented with pulmonary embolism and was diagnosed with an IPE on transthoracic and transesophageal echocardiography. He was subsequently treated with heparin and thrombolysis. A comprehensive review of the English literature over the past 20 years identified 60 previously reported cases of IPE. This report discusses the main clinical features, the diagnostic role of echocardiography and the outcome of medical and surgical treatment strategies in patients with IPE. Based on the literature to date, we recommend that patients with impending paradoxical embolism be treated with initial systemic heparinization followed by emergent surgical embolectomy if the surgical risks are acceptable.