In Brief:
We compared the coronary arterial response and clinical usefulness between selective intracoronary injection of ACh and ER. We performed 1,508 selective spasm provocation tests, consisting of 873 ACh tests and 635 ER tests from 1991 to 2002. Intracoronary ACh provoked spasms in 36.0% of patients and intracoronary ER induced spasms in 29.8% of patients. In patients with ischemic heart disease, the incidence of provoked spasms was not different between ACh tests (50.9%) and ER tests (43.8%). In contrast, the frequency of provoked spasms with ACh tests was significantly higher than that with ER testings (11.0% vs. 6.4%, p<0.05) in patients without ischemic heart disease. Major complications were observed in 1.4% of patients with ACh tests and in 0.2% of patients with ER tests. However, no serious irreversible complications, such as death or acute myocardial infarction, were observed in this study. In conclusion, both selective ACh and ER tests were useful as spasm provocation tests.