Spinal cord stimulation (SCS) modifies cardiac‐related dorsal root ganglia (DRG) afferent neurons in response to myocardial ischemia

Abstract

ObjectiveTo determine if SCS modulates the capacity of cardiac sympathetic afferent neurons to transduce regional myocardial ischemia.MethodsUsing extracellular recording techniques in anesthetized canines, cardiac‐related DRG neurons (T1‐T3 spinal levels) were identified by multimodal stimulation of the left anterior descending (LAD) region. Then neuronal responses to transient (1 min) LAD coronary artery occlusion (CAO) were evaluated prior to and following SCS (T1‐T3 spinal level; 50Hz, 90% motor threshold; 20 min).ResultsLAD CAO caused a ~4 fold increase in cardiac afferent neuronal activity that persisted for at least 30 minutes following reperfusion. SCS doubled basal cardiac afferent neuronal activity, doing so in a stochastic manner. Following SCS, LAD CAO evoked no further increase in such activity.ConclusionTransient myocardial ischemia activates primary afferent inputs to the spinal cord well beyond stressor application. Pre‐emptive SCS obtunds sensory transduction of the ischemic myocardium to spinal cord neurons. (Supported by HL71830.)