A total of 349 patients with vasospastic angina were followed in eight centers in Japan for a period of 3.4 +/- 0.1 years (mean +/- SE). Ninety-eight percent of patients were treated with calcium blockers. Twenty-one episodes of myocardial infarction occurred in 18 patients (5%), including two fatal myocardial infarctions. The rate of myocardial infarction was higher (p less than .01) in patients with a fixed stenosis of 90% or greater than in patients with a fixed stenosis of less than 90% or normal coronary arteries. Myocardial infarctions occurred predominantly during hospital stays or at a time when the frequency of vasospastic angina increased. There were five sudden deaths (2%). Only one patient suffering sudden death had a fixed stenosis of 75% or greater. Serious arrhythmias were noted in 49 patients (14%). The risk of arrhythmias did not depend on the presence of a fixed stenosis of 75% or greater. These results suggest that cardiac events are rather infrequent in Japanese patients with vasospastic angina who are receiving treatment with calcium blockers and that the presence of a severe fixed stenosis markedly increases the risk of myocardial infarction but not the risk of arrhythmias.