title: Neuromodulation therapy does not influence blood flow distribution or left-ventricular dynamics during acute myocardial ischemia.
abstract: OBJECTIVE
  Electrical stimulation of the dorsal aspect of the upper thoracic spinal cord is used increasingly to treat patients with angina pectoris refractory to conventional therapeutic strategies. The purpose of this study was to determine whether spinal cord stimulation (SCS) in dogs affects regional myocardial blood flow and left-ventricular (LV) function before and during transient obstruction of the left anterior descending coronary artery (LAD).
  
  
  METHODS
  In anesthetized dogs, regional myocardial blood flow distribution was determined using radiolabeled microspheres and left-ventricular function was measured by impedance-derived pressure-volume loops. SCS was accomplished by stimulating the dorsal T1-T2 segments of the spinal cord using epidural bipolar electrodes at 90% of motor threshold (MT) (50 Hz, 0.2-ms duration). Effects of 5-min SCS were assessed under basal conditions and during 4-min occlusion of the LAD.
  
  
  RESULTS
  SCS alone evoked no change in regional myocardial blood flow or cardiovascular indices. Transient LAD occlusion significantly diminished blood flow within ischemic, but not in non-ischemic myocardial tissue. Left ventricular pressure-volume loops were shifted rightward during LAD occlusion. Cardiac indices were altered similarly during LAD occlusion and concurrent SCS.
  
  
  CONCLUSIONS
  SCS does not influence the distribution of blood flow within the non-ischemic or ischemic myocardium. Nor does it modify LV pressure-volume dynamics in the anesthetized experimental preparation.
authors.affiliation: Department of Medicine, Laval University, Quebec, Canada. john.kingma@med.ulaval.ca
authors.forename: J G
authors.initials: JG
authors.lastname: Kingma
authors.forename: B
authors.initials: B
authors.lastname: Linderoth
authors.forename: J L
authors.initials: JL
authors.lastname: Ardell
authors.forename: J A
authors.initials: JA
authors.lastname: Armour
authors.forename: M J
authors.initials: MJ
authors.lastname: DeJongste
authors.forename: R D
authors.initials: RD
authors.lastname: Foreman
mesh_terms: D000208:Acute Disease; D000818:Animals; D002306:Cardiac Volume / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology*; D004285:Dogs; D004599:Electric Stimulation Therapy; D005260:Female; D006321:Heart / Q000294:innervation / Q000502:physiology; D008297:Male; D017202:Myocardial Ischemia / Q000503:physiopathology* / Q000628:therapy*; D018377:Neurotransmitter Agents / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology; D017725:Ventricular Pressure / Q000502:physiology
chemical_list: D018377:Neurotransmitter Agents