Table 1.

Spinal cord stimulation: bradycardia responses to mediastinal nerve stimulation

Before SCS (control)After SCS
Protocol A: SCS (11 animals)
# sites62/8647/86*
Sinus CL, ms416 (42)435 (47)
Bradycardia CL, ms535 (83)534 (98)
CL prolongation, %30 (24)23 (20)
Protocol B: testing reproducibility (without SCS) (5 animals)
# sites27/2825/28
Sinus CL, ms403 (25)397 (22)
Bradycardia CL, ms541 (72)524 (75)
CL prolongation, %35 (20)33 (22)
Protocol C: SCS after bilateral stellectomy (5 animals)
# sites27/3127/31
Sinus CL, ms529 (71)521 (60)
Bradycardia CL, ms712 (166)724 (157)
CL prolongation, %34 (23)39 (26)
  • Data are presented as means (SD). # sites, proportion of total active sites from which bradycardias were elicited by mediastinal nerve stimulation. Atrial cycle length (CL) measurements were made during baseline “sinus” rhythm (i.e., before mediastinal nerve stimulation) and during bradycardia; their difference is expressed as percent CL prolongation. These variables were measured before (control) and after spinal cord stimulation (SCS) in 11 animals with intact stellate ganglia (protocol A), in reproducibility experiments without SCS (protocol B), and in animals with bilateral stellectomy (protocol C). Differences between control and trial data were tested using t-test for paired data (continuous variables) or χ2 (incidence).

  • * P < 0.03 and

  • P < 0.006 error rejecting the null hypothesis.