Abstract 12134: The Role of Spinal Extra-Cardiac Neural Ganglia in Modulation of Myocardial Excitability
Background: Enhanced cardiac sympathetic tone has been associated with ventricular arrhythmias and sudden cardiac death. Neuraxial modulation provides an important avenue for therapeutic intervention. However, the role of spinal extra-cardiac neural ganglia in modulation of myocardial excitability during sympathetic efferent stimulation remains unknown. The purpose of this study is to investigate the role of spinal neuraxial control of myocardial excitability during sympathetic efferent stimulation in a porcine model.
Methods: Female Yorkshire pigs (n=5) underwent surgical exposure of the heart and right and left stellate ganglia through sternotomy. A 56-electrode sock was placed over the ventricles to record activation recovery interval (ARI), a surrogate measure of action potential duration. Animals underwent left stellate ganglion (LSG) stimulation for 30 second in intact and followed by decentralization of bilateral stellate ganglia.
Results: LSG stimulation shortened global ARI from 357±35 ms to 315±43 ms (p≤0.05) and increased dispersion in ARI from 407±75 ms2 to 2260±937 ms2 (p≤0.05) from baseline in intact animals. With decentralization of bilateral stellate ganglia LSG stimulation further shortened ARI (298±28 ms vs. 315±43 ms) and increased dispersion (3000±1311 ms2 vs. 2260±937 ms2) compared to intact animals.
Conclusio: n: Decentralization of extra-cardiac neural ganglia during sympathetic efferent stimulation aggravates the cardiac excitability suggesting a significant role of central-peripheral neural interaction in cardiovascular modulation. If such interactions are disrupted, effective control of cardiac electrical indices are compromised, leading to arrhythmogenesis. This finding provides mechanistic insight into the neuraxial modulation in reducing cardiac arrhythmias.
- © 2013 by American Heart Association, Inc.