Paradoxical embolism occurs following the passage of embolic material from the venous to the arterial circulation through a right to left shunt--frequently a patent foramen ovale. The diagnosis is usually presumptive when arterial emboli occur in the appropriate clinical setting. We describe a case of impending paradoxical embolism in a patient with massive pulmonary embolism. Transoesophageal echocardiography revealed a thromboembolus straddling a patent foramen ovale. The patient underwent emergency removal of the intracardiac clot with closure of the patent foramen ovale.