Objectives: The pathogenesis of vasospastic angina is not completely understood, but endothelial dysfunction and smooth muscle hyper-reactivity are known to be involved. The prevalence of coronary spastic angina is apparently higher in oriental people than in west counterparts. We evaluated characteristics of acute myocardial infarction (AMI) in vasospastic angina (VA) without organic coronary heart disease. Methods: VA was defined as transient luminal narrowing above 90% of coronary artery and chest pain during coronary spasm provocation test by injection of intracoronary acetylcholine. AMI in VA was defined as cardiac marker (CK-MB, troponin-I) elevation above upper normal limit with no organic coronary heart disease in angiography and confirmed VA in spasm provocation test. Results: 672 coronary spasm provocation tests were performed from January 2003 to June 2005 in Kangnam St. Mary���s hospital. We diagnosed coronary spastic angina in 292 patients by spasm provocation test. Among 292 patients, 21 patients experienced AMI. 7.2% patients in VA suffered from AMI without organic coronary disease. 1 patient suffered from AMI in admission. 20 patients initially visited ER for AMI. 16 patients had ST elevation in initial ECG (Inferior wall:9 patients, anterior wall:7 patients). There is no difference of baseline characteristics between AMI group and VA group. In echocardiography, except for ejection fraction and wall motion (P<0.001), there were no differences between two groups. 20 patients of AMI patient were not diagnosed VA before AMI. After taking medication for VA, AMI patient did not again experience severe chest pain to visit ER or to cause AMI. 14 patients experienced severe emotional stress within 5 day before AMI attack (P<0.001). In spasm provocation test, the AMI patients had more multivessel and diffuse spasm compared with VA patients (P<0.001) Conclusion: Clinically, AMI patients in VA were usually first attack of severe chest pain and discontinuing medication could caused AMI among known VA patients. Most AMI patients had emotional stress before AMI attack. Spasm provocation test in AMI patients showed more multivessel and diffuse spasm compared with VA patients