EFFECTS OF SPINAL-CORD STIMULATION ON CORONARY BLOOD-FLOW VELOCITY

Background Spinal cord stimulation (SCS) has been used in the treatmen t of severe angina pectoris since the 1980s. Several studies have show n both an antianginal and an anti-ischaemic effect. There are several theories about the mechanism behind the anti-ischaemic effect of SCS, including the possibility that it is dependent on an increase in coron ary flow velocity. Objective To determine if there were effects of SCS on coronary flow velocity during cardiac stress. Method Eight patient s with severe anginal pain secondary to coronary artery disease who ha d been implanted with an SCS device were included in the study. In add ition, four patients with syndrome X were examined, If possible, a Dop pler guidewire was placed in the vessel corresponding to the ischaemic area revealed on a prior myocardial scintigram. A temporary pacemaker electrode was placed in the right atrium. Atrial pacing started at 80 beats/min and increased by 10 beats/min every 2 min until the patient experienced moderate angina; the pacing frequency was then maintained at the same level. After 2 min of pacing at this frequency, SCS treat ment commenced; after a further 5 min, pacing was stopped. Throughout the procedure, coronary flow velocity, assessed as average peak veloci ty (APV), was monitored continually. Results APV increased during paci ng in all the patients with coronary artery disease (mean increase 53% ; P< 0.02). There were no significant changes in APV during maximum pa cing frequency when stimulation was introduced. Conclusions The result s of this study do not support the theory that the anti-ischaemic effe ct of SCS is dependent on an increase in coronary flow velocity. Coron ary Artery Dis 9:273-278 (C) 1998 Lippincott-Raven Publishers.