To evaluate both the safety and clinical use of predischarge symptom-limited exercise testing after successful uncomplicated percutaneous transluminal coronary angioplasty (PTCA), 100 patients were randomized to undergo exercise testing (n = 50) or no exercise testing (n = 50). There were no differences in clinical or angiographic characteristics between the groups. Exercise testing was performed 38 +/- 14 hours after PTCA. Patients who exercised achieved 71 +/- 12% of predicted maximal heart rate, with 38% reaching greater than or equal to stage III of the Bruce protocol. No patient in either group developed cardiac complications during 48-hour follow-up. Of the 11 patients with a positive test result, 92% had angiographically incomplete revascularization. Attending physicians (n = 16) were questioned both before and after exercise testing about when, after discharge, they would allow their patient to perform each of 11 specific activities of daily living. Questionnaires were administered to physicians at similar time frames for patients in the no-exercise group. Comparison of the responses between initial and repeat questionnaires showed that patients in the exercise group (with a test result negative for ischemia) were allowed to perform 7 of 11 activities, including return to work, earlier (p less than 0.05) than the no-exercise patients. These data indicate that in this well-defined group of patients, symptom-limited exercise testing early after PTCA appears to be safe, and alters physician management in allowing patients with a negative test result to return to various activities at an earlier date. Such testing may be useful in counseling patients after PTCA.