Abstract 13297: Left Ventricular Electro-Mechanical Dispersion Induced by Stellate Ganglia Stimulation
Background: The sympathetic nervous system plays a significant role in the genesis of ventricular arrhythmia. Electrical dispersion in myocardium during sympathetic stimulation facilitates malignant arrhythmia, leading to sudden cardiac death. Mechanical dispersion, which can be measured as regional heterogeneity of contraction by myocardial strain echocardiography has been recently shown to be a novel marker of arrhythmias. We hypothesized that electrical abnormalities induced by stellate ganglia stimulation can lead to mechanical dispersion.
The aim of this study was to evaluate the left ventricular (LV) electro-mechanical dispersion during sympathetic efferent stimulation.
Methods: Female Yorkshire pigs (n=6) underwent surgical exposure of the heart and right and left stellate ganglia (RSG, LSG) through sternotomy. A 56-electrode sock was placed over the ventricles to record activation recovery interval (ARI), a surrogate measure of action potential duration. Longitudinal strain was measured by speckle tracking echocardiography and ARI were recorded at baseline and during either LSG or RSG stimulation. The standard deviation of time to maximum myocardial shortening in a 16-segment LV model was calculated as a parameter of mechanical dispersion.
Results: LSG and RSG stimulation significantly increased dispersion in global ARI from baseline by 235±38% and 105±18%, respectively (p<0.01). LSG and RSG stimulation also increased mechanical dispersion by 132±21% and 72±10%, respectively (p<0.05). The mechanical dispersion has a strong correlation with ARI dispersion (r=0.88, p=0.04).
Conclusions: Electro-mechanical dispersion was more pronounced during LSG stimulation compared to RSG stimulation. These parameters assessed by myocardial strain and ARI may add important information about the role of stellate ganglia in modulation of ventricular arrhythmogenesis.
- © 2013 by American Heart Association, Inc.