The effects of transcutaneous electrical nerve stimulation in patients with severe angina pectoris

Abstract

The pain-relieving effects of transcutaneous electrical nerve stimulation (TENS) were investigated in patients with severe angina pectoris first with respect to systemic and coronary hemodynamics and myocardial metabolism during pacing-induced angina and second in a controlled long-term study. Two series of patients with severe angina pectoris (NYHA class III to IV) were studied (13 patients in the pacing study and 23 in the long-term study). In the pacing-induced angina study there was increased tolerance to pacing (142 ± 23 compared with 124 ± 20 beats/min tolerated, p < .001), improved lactate metabolism (2 ± 36% compared with -18 ± 43%, p < .01), and less pronounced ST segment depression (2.3 ± 1.1 compared with 2.9 ± 2.6 mm, p < .05) with TENS. In the long-term study the effects of TENS were measured by means of repeated bicycle ergometer tests, frequency of anginal attacks, and consumption of short-acting nitroglycerin. TENS was used regularly for 1 hr three times per day. The TENS treatment group had increased work capacity (637 ± 308 vs 555 ± 277 W·min, p > .001), decreased ST segment depression (2.3 ± 1.1 vs 3.6 ± 1.6 mm, p < .001), reduced frequency of anginal attacks (p < .05), and reduced consumption of short-acting nitroglycerin per week (p < .05) compared with the control group. The observed effects were mainly due to decreased afterload resulting from systemic vascular dilatation.