Background:Typical or atypical chest pain during the acetylcholine (Ach)-provocation test may be a subjective symptom but may play an important role as a clinical parameter for the Ach-induced endothelial dysfunction results.We investigated the clinically relevant impact of chest pain during the Ach provocation test on the angiographic characteristics of Ach-induced endothelial dysfunction.Methods:A total 1085 pts with typical or atypical anginal symptoms underwent diagnostic coronary angiography(CAG) and Ach provocation test.Among them,539 pts with endothelial dysfunction on Ach-provocation test were divided into two groups according to occurrence of chest pain during the test.We analyzed the ischemic ECG changes and angiographic characteristics during the significant narrowing according to the presence of chest pain.Results:Baseline characteristics and coronary risk factors were similar between the two groups,except smoking (40.4%vs27.3 % in no chest pain, p=0.007) and female (65.5%vs47.2 % in no chest pain, p<0.001).A total 539 pts (pts;248 men, mean age; 58.01짹11.13 years) showed Ach-induced endothelial dysfunction.The ECG changes in chest pain group was higher compared with those of pts without chest pain(14.7%vs7.5%, p=0.007).The chest pain group showed more multiple, diffuse, significant endothelial dysfunction, considering more significant vasospasm compared with those of the pts without chest pain during the test(Table).Conclusion:When we categorized all pts with Ach-induced endothelial dysfunction into two groups according to the occurrence of chest pain during Ach provocation test, chest pain was associated with more ischemic ECG changes, multi-vessel involvement, diffuse and severe Ach-induced endothelial dysfunction.