BACKGROUND: The diagnostic significance of ECG ergonovine test and the incidence of vasospastic angina in patients with chest pain are still uncertain. METHODS: From May 1998 to June 1999, 133 consecutive patients with chest pain were admitted for diagnostic coronary angiography. ECG ergonovine provocation tests were performed in 64 patients who have a clinical history suggesting vasospatic angina, including 27 of 28 patients with vasospastic angina documented electrocardiographically, or who's coronary angiographic findings could not be explained by their clinical history. Ergonovine was administered intravenously in incremental dose of 0.05, 0.1, 0.2, 0.3, 0.4 mg up to total cumulative dosage of 1.0mg during coronary angiography(41 cases), in the exercise laboratory(21 cases) or both(2 cases). RESULTS: Of 133 patients with chest pain, vasospastic angina was documented in 32(24%), unstable angina in 52(34%), stable angina in 10(8%), and others in 39(29%). Angiography demonstrated coronary spasm in 4 additional patients as well as 22 patients with vasospastic angina documented electrocardiographically, but ergonovine tests in the exercise laboratory showed positive response in 5 of 6 patients with vasospastic angina documented. Among the 25 patients with coronary spasm proved angiographically during ergonovine test, ECG findings at the time of coronary spasm were ST segment elevation in 21(84%), depression in 1(4%) and no change in 3(12%) patients, who had branch vessel spasm, 3 vessel spasm or incomplete spasm on coronary angiogram. Of the 31 patients with vasospastic angina who underwent ergonovine tests, positive response occurred in 24(77%) after a cumulative dose of < or = 0.4mg and in additional 3(10%) after the higher dose of >0.4mg. However the other 4(13%) had no ECG changes even after the higher dose(>0.4mg) of ergonovine. CONCLUSION: This results suggest that vasospastic angina appear to be a common cause of chest pain, and ECG ergonovine test with high dose can improve diagnostic sensitivity but cannot detect some patients with vasospastic angina.