In the clinical grounds, patients with ≥90 % luminal narrowing during acetylcholine (ACh) testing had variable response. We investigated ischemic findings and chest symptoms in patients with ≥90 % luminal narrowing when performing ACh tests, retrospectively. We performed 763 ACh tests over 13 years (2001–2013). We analyzed chest symptoms and positive ischemic ECG changes during ACh tests. More than 90 % luminal narrowing was found in 441 patients (57.8 %) including 355 patients in the right coronary artery (RCA) and 363 patients in the left coronary artery (LCA). Chest symptom was observed in 386 patients (87.5 %) including 293 patients in the RCA and 304 patients in the LCA. ST elevation was found in 161 patients including 110 in the RCA and 85 patients in the LCA, while ST depression was recognized in 146 patients including 119 patients in the RCA and 117 patients in the LCA. Three quarter of patients with ≥90 % luminal narrowing had significant ischemic ECG changes, whereas two-third of patients with ≥90 % luminal narrowing complained usual chest pain accompanied with significant ischemic ECG changes. Unusual chest symptom was complained in 7.3 % patients with ≥90 % luminal narrowing. Neither chest symptom nor ECG changes were found in 30 patients (6.8 %) with ≥90 % luminal narrowing. A third of these patients had ischemic findings on non-invasive tests before catheterization and six patients had subtotal or total occlusion. We should realize some limitation to define positive coronary spasm based on the ischemic ECG change and chest symptom during ACh tests.