Acute myocardial infarction resulting from the migration of a Greenfield filter. A paraplegic patient who underwent the placement of Greenfield filters to prevent pulmonary emboli had one of the filters migrate proximally to the junction of the inferior vena cava and right atrium, then into the right atrium a few months later. This resulted in an acute myocardial infarction by apparently causing an intimal dissection of the posterior descending artery. Treatment, follow-up and causes of filter migration are discussed. 