EFFECT OF TRANSCUTANEOUS ELECTRICAL NERVE-STIMULATION ON CORONARY BLOOD-FLOW

Background Although neurostimulation has been shown to be of benefit i n angina pectoris, the exact mechanism of its action is not clear. Thi s study was performed to examine the effect of transcutaneous electric al nerve stimulation on coronary blood flow. Methods and Results The e ffect of transcutaneous electrical nerve stimulation was studied in 34 syndrome X patients (group 1), 15 coronary artery disease patients (g roup 2), and 16 heart transplant patients (group 3). Coronary blood fl ow velocity (CBFV) in the left coronary system was measured at rest an d after a 5-minute stimulation period with a Judkins Doppler. There wa s a significant increase in the resting CBFV in group 1 (from 6.8+/-4. 1 to 10.5+/-5.7 cm/s, P<.001) and group 2 (from 6.8+/-4.1 to 10.5+/-5. 7 cm/s, P<.001). However, there was no significant change in the resti ng CBFV in group 3. There were no significant changes in the coronary arterial diameters as a result of neurostimulation. There was a signif icant decrease in the epinephrine levels in group 1 (from 79.6+/-17.8 to 58.5+/-17.5 ng/L, P=.01) and group 2 (from 102.2+/-27.2 to 64.1+/-1 9.1 ng/L, P=.01). Conclusions Transcutaneous electrical nerve stimulat ion can increase resting coronary blood flow velocity. The findings su ggest that the site of action is at the microcirculatory level and tha t the effects may be mediated by neural mechanisms.