occurrence of transient uwave inversion during vasospastic anginal attack is not related to the direction of concurrent stsegment shift study objectives we sought to assess the incidence of transient uwave inversion during vasospasm of the left anterior descending coronary artery lad with stsegment depression as opposed to that with stsegment elevationdesign retrospective studysetting cardiology division of acutecare hospitalspatients we studied 49 patients with vasospastic angina whose vasospasm was induced in the lad not in the left circumflex coronary artery by intracoronary injection of acetylcholinemeasurements and results the ecg traces obtained during acetylcholineinduced vasospasm of the lad were examined based on the direction of stsegment shift the patients were categorized into two groups the stsegment elevation group n 27 and the depression group n 22 there were no differences in age gender or cardiovascular risk factors between the two groups the distribution of the spastic site in the lad was also similar a total reduction in luminal diameter during a provoked attack was more often observed in the stsegment elevation group than in the stsegment depression group 37 vs 9 p 002 collateral circulation to the lad was found in only one patient in each group there were no differences between the two groups in heart rate systolic bp and double product of heart rate and systolic bp during the attack the incidence of acetylcholineinduced anginal attack with uwave inversion in the stsegment depression group was nearly as high as that in the stsegment elevation group 77 vs 78 p 099conclusions the development of transient uwave inversion during vasospasm of the lad induced by intracoronary injection of acetylcholine does not depend on the magnitude of myocardial ischemia as judged by the direction of stsegment shift