Submaximal exercise testing after unstable angina.

Sixty-one consecutive men, mean age 56 years, who fulfilled criteria for unstable angina and who responded to medical therapy, underwent submaximal exercise testing prior to hospital discharge and at least 3 days after their last episode of angina. Forty-two patients were receiving propranolol at the time of exercise. Submaximal exercise was targeted to 120 beats/minute and strict criteria for the premature termination of each study were followed. Follow-up data were available on 55 patients post-discharge over a period of 6 to 36 weeks. No patient suffered recurrence of unstable angina or myocardial infarction due to the exercise test. Exercise was prematurely terminated by an ischemic response (chest pain and/or ST segment changes) in 34 patients (56%) and by leg fatigue in 13 patients (21%). Only five patients had exercise-induced ventricular ectopic activity, four of whom were not receiving propranolol. Nine patients achieved the target heart rate. Exercise-induced abnormal electrocardiographic changes predicted the postdischarge recurrence of episodes of unstable angina (p less than 0.05). Comparison of predischarge submaximal exercise data with postdischarge maximal exercise shows that recovery in cardiovascular function after unstable angina occurs soon after stabilization and prior to the submaximal test.