Spinal cord stimulation treatment for angina pectoris: more than a placebo?
BACKGROUND
The effects of thoracolumbal spinal cord stimulation (SCS) are confined to restricted microcirculatory areas. This limitation is generally attributed to a predominantly segmental mode of action on the autonomic nervous system. The goal of this study was to determine whether SCS applied close to supraspinal autonomic centers would induce generalized hemodynamic changes that could explain its alleged antianginal properties.


METHODS
Invasive hemodynamic tests were performed in 15 anesthetized Göttingen minipigs submitted to iterative cervical SCS of various duration and intensity.


RESULTS
Hemodynamic changes exceeding 10% were observed in 59 of 68 SCS sessions (87%). Their extent and time to peak varied with SCS intensity. At 2, 5, and 10 V, significant (t test p < 0.05) peak changes occurred in cardiac output (+34%, +29%, and +28%, respectively), stroke volume (+19%, +16%, +15%), mean pressure (+9%, +27%, +40%), heart rate (+14%, +23%, +14%), systemic (-17%, NS, NS), and pulmonary vascular (25%, NS, NS) resistances. Strikingly, at 2 V, the increase in cardiac output (+34%) was higher than the synchronous rise in rate pressure product (+22%), indicating efficient cardiac work. At 10 V, however, the cardiac work was inefficient (rate pressure product + 53%/cardiac output + 28%).


CONCLUSIONS
Low-voltage cervical neuromodulation reduces the postcharge and improves cardiac work efficiency. The resulting reduction in oxygen myocardial demand may account for decreased anginal pain.
Gersbach
P A
PA
Department of Cardiovascular Surgery, University Hospital of Lausanne, Switzerland. philippe.gersbach@chuv.hospvd.ch
Hasdemir
M G
MG
Eeckhout
E
E
von Segesser
L K
LK
D000787:Angina Pectoris / Q000503:physiopathology / Q000628:therapy*; D000818:Animals; D004599:Electric Stimulation Therapy; D004562:Electrocardiography; D004567:Electrodes, Implanted; D006439:Hemodynamics; D013116:Spinal Cord; D013556:Swine, Miniature