TRANSCUTANEOUS ELECTRICAL NERVE-STIMULATION IN UNSTABLE ANGINA-PECTORIS

Background Silent ischemia is a strong predictor of unfavorable outcom e in unstable angina pectoris. Dynamic continuous vector cardiography provides online detection of ischemic episodes. Transcutaneous electri cal nerve stimulation (TENS) has been reported to have antianginal eff ects in patients with severe coronary artery disease and this is assoc iated with a reduction in myocardial ischemia. The aim of the present study was to investigate the applicability of TENS in patients with un stable angina in the coronary care unit and the effects on vector card iographic and biochemical markers of ischemia. Methods Thirty patients (14 in the TENS group and 16 in a placebo group) were included in a s ingle-blind, placebo-controlled study after being admitted to the coro nary care unit. Continuous vector cardiography, leakage of cardiac enz ymes and consumption of analgesics were recorded for 24 h. Results TEN S was well tolerated and did not interfere with standard treatment, al though vectorcardiographic recording during actual stimulation was dis turbed. There was a reduction in the number of silent ischemic ST chan ge vector magnitude episodes (P = 0.02) and their duration (P = 0.01) in the TENS-treated group, and a nonsignificant reduction in the total number of ST change vector magnitude (painful plus silent) episodes ( P = 0.09) and their duration (P = 0.05) and in leakage of cardiac enzy mes (P = 0.12). There were no detectable differences in terms of episo des of pain leading to stimulation or consumption of analgesics. Concl usions TENS seems to be a safe additional treatment in unstable angina pectoris and may reduce the number of ischemic events, by mechanisms apparently unrelated to the reduction of pain.