Coronary artery perforation (CAP) after percutaneous coronary intervention is a rare, but serious complication. It can cause cardiac tamponade, acute myocardial infarction or death. The treatments of CAP involve prolonged balloon inflation, emergent surgery, coil embolization, and implantation of covered stent. We have successfully performed the emergent microcoil embolization in a patient with uncontrolled Ellis grade 3 guidewire-induced CAP resulting in delayed cardiac tamponade. Contrasting our usual expectation, the 1-year follow-up angiography showed a patent flow at the embolized site.