Transcutaneous nerve stimulation in patients with coronary arterial disease: haemodynamic and biochemical effects.

Low-frequency transcutaneous nerve stimulation (TNS) is known to produce widespread and prolonged vasodilation in skin and muscles. In the present study the effects of low-frequency TNS on coronary and systemic haemodynamics, myocardial blood flow, myocardial oxygen consumption, myocardial free fatty acid and lactate uptake were measured at rest in 16 normotensive patients, with coronary heart disease, undergoing diagnostic cardiac catheterization. In addition, vasoactive intestinal polypeptides (VIP) and noradrenaline were measured in the coronary sinus and the aorta. The study was randomized and double-blind, with half of the patients serving as placebo controls. A stimulation period of 20 min caused a significant lowering of mean femoral arterial pressure and systemic vascular resistance measured at 15 and 30 min after the start of TNS (P less than 0.01). There was no significant change in the other parameters mentioned. The hypotonic effect is considered to be due to increased peripheral microcirculation resulting from sympatho-inhibition.