Cardiac sympathetic denervation, CSD, is reported to reduce burden of ventricular tachy-arrhythmias (VT/VF) in cardiomyopathy patients, but the mechanisms behind this benefit are unknown. In addition, the relative contribution to cardiac innervation of the middle cervical ganglia (MCG), which may contain cardiac neurons, and is not removed during this procedure, is unclear. The purpose of this study was to compare sympathetic innervation of the heart via the MCG vs. stellate ganglia, assess effects of bilateral CSD on cardiac function and VT/VF, and determine changes in cardiac sympathetic innervation after CSD to elucidate mechanisms of benefit in 6 normal and 18 infarcted pigs. Electrophysiological and hemodynamic parameters were evaluated at baseline, during bilateral stellate and during bilateral MCG stimulation in 6 normal and 12 infarcted animals. Bilateral CSD (removal of bilateral stellates and T2 ganglia) was then performed, and MCG stimulation repeated. In addition, in 18 infarcted animals VT/VF inducibility was assessed pre- and post-CSD. In infarcted hearts, MCG stimulation resulted in greater chronotropic and inotropic response than stellate ganglia stimulation. Bilateral CSD acutely reduced VT/VF inducibility by 50% in infarcted hearts and prolonged global activation recovery interval. CSD mitigated effects of MCG stimulation on dispersion of repolarization and T-peak to T-end interval in infarcted hearts, without causing hemodynamic compromise. This data demonstrate that the MCG provides significant cardiac sympathetic innervation before CSD and adequate sympathetic normal after CSD, maintaining hemodynamic stability. Bilateral CSD reduces VT/VF inducibility by improving electrical stability in infarcted hearts in the setting of sympathetic activation.
- ventricular arrhythmias
- sympathetic nervous system
- cardiac sympathetic denervation
- Copyright © 2016, American Journal of Physiology-Heart and Circulatory Physiology