The feasibility of outpatient electrophysiologic testing was examined by reviewing 100 consecutive outpatient tests performed in 95 patients. Seventy-one of the patients (75%) had no underlying heart disease. The electrophysiologic tests were performed to evaluate supraventricular tachycardias (n = 47), nonsustained ventricular tachycardia (n = 20), unexplained syncope (n = 21), palpitation (n = 9) or intermittent heart block (n = 2). A mean of 2.8 +/- 0.5 6F electrode catheters were inserted through a femoral vein. An electrode catheter was inserted into a subclavian or internal jugular vein in 28 tests and a 5F cannula was inserted into a femoral artery to monitor the blood pressure in 20 tests. The results of 61 tests (61%) were abnormal. Patients were monitored for a mean of 3.8 +/- 1.2 h after the procedure and then discharged. No complications occurred. For cost analysis a subgroup of 60 of these patients was matched for age, gender, heart disease and indication for electrophysiologic testing with a group of 60 patients who underwent electrophysiologic testing as inpatients. Physicians' fees for the two groups were similar; however, the mean hospital charge was $5,845 +/- 3,763 for the inpatient group compared with only $2,120 +/- 1,244 for the outpatient group (p less than 0.001). Thus, outpatient electrophysiologic testing is feasible and safe and results in substantial cost savings in patients without life-threatening arrhythmias.