A 31-year-old female smoker on the combined oral contraceptive pill presented late with an anterior myocardial infarction. At emergency coronary angiography she was found to have a coronary artery thrombus occluding the left anterior descending artery, with no other coronary artery disease. Subsequent saline bubble contrast echocardiography revealed a patent foramen ovale. The presumptive diagnosis was paradoxical coronary artery embolism resulting in myocardial infarction. We suggest that all patients with coronary artery thrombus and limited evidence of atheromatous disease be considered for contrast echocardiography to exclude a patent foramen ovale. However, whether a patent foramen ovale in this context should be closed remains uncertain.