INTRODUCTION: The purpose of this study was to investigate the safety of performing a dipyridamole stress test and to explore the incidence of reversible perfusion defects on myocardial perfusion imaging, five to six days after primary percutaneous coronary intervention (PCI).METHODS: Forty-one patients underwent myocardial perfusion imaging using a dipyridamole stress test, five to six days after primary PCI.RESULTS: Headache, chest pain, and dizziness were the most common side effects seen after dipyridamole administration. All occurrences were mild and short lasting. ST changes on the electrocardiogram were also seen in 12% of patients. Reversible perfusion defects occurred in 17%.CONCLUSIONS: This is one of the few studies to investigate patients using a dipyridamole stress test early after primary PCI. We conclude that it is safe to perform myocardial perfusion imaging under dipyridamole administration, just a few days after primary PCI. Additionally, a high incidence (17%) of myocardial perfusion defects was seen in this group of patients. According to our investigational protocol, a second myocardial perfusion imaging examination is scheduled for six months later, in order to clarify how many of these patients suffer from restenosis, or whether the finding was merely due to early endothelial dysfunction.