To study the effect of transcutaneous electrical nerve stimulation (TENS) on coronary vasomotion, patients with New York Heart Association class III angina pectoris and significant single-vessel left coronary artery disease and who were also scheduled for elective percutaneous transluminal coronary angioplasty, were allocated to a study group (precordial actual TENS, n = 10) and a control group (precordial simulated TENS, n = 5, and TENS on the back, n = 3). Coronary volumetric flow was assessed in the stenotic and nonstenotic coronary artery before and after neurostimulation. The diameter (in millimeters) of the stenotic coronary artery was reduced in the study group after actual TENS (from 2.73 +/- 0.55 by 0.12 +/- 0.11; p = 0.008). In the nonstenotic coronary artery, the diameter increased in the study group (from 2.64 +/- 0.43 by 0.24 +/- 0.15; p = 0.01). In both the stenotic and nonstenotic coronary arteries, no effect was shown on the average peak velocity (centimeters per second) in the study group. The coronary volumetric flow (milliliters per minute) was reduced in the stenotic artery of the study group (from 62 +/- 18 by 8 +/- 7; p = 0.007). In the nonstenotic coronary artery, volumetric flow increased in the study group (from 57 +/- 18 by 11 +/- 10; p = 0.007). In the control group, simulated TENS and TENS on the back had no effect on the diameter of the artery, average peak velocity, or volumetric flow. In addition, in all patients, TENS had no effect on the total volumetric flow of the left coronary artery and hemodynamic variables during the study period. This observation suggests that TENS modulates regional coronary vasomotion in patients with coronary artery disease.