Abstract 14040: Subcutaneous Nerve Activity and Spontaneous Ventricular Arrhythmias in Ambulatory Dogs
Background: Increased sympathetic nerve activity is a trigger of cardiac arrhythmias. We hypothesize that it is feasible to record sympathetic nerve activity subcutaneously in ambulatory dogs, and that subcutaneous sympathetic nerve activity (SCNA) is associated with the development of spontaneous ventricular tachycardia (VT) and ventricular fibrillation (VF).
Methods and results: We simultaneously recorded the nerve activity from the left stellate ganglion (SGNA) and from the thoracic subcutaneous space (SCNA) in 6 ambulatory dogs with complete heart block, myocardial infarction and nerve growth factor infusion to the left stellate ganglion. The electrical signals were sampled at 1K, and high pass filtered at 150 Hz. Two dogs died suddenly of VF. Both VF episodes were preceded by nearly continuous SCNA (150 s and 42 s) and SGNA (150 s and 42 s). There was SCNA within 15 s before 33 (76.7%) of 43 VT (Figure, asterisks indicate SCNA), 19 (42.2%) of 45 frequent couplets or bigeminy and 19 (42.2%) of 45 PVCs. Similar incidence was identified for SGNA (76.7%, 64% and 53.3%, respectively). Significantly progressive increase in integrated SGNA (in mV-s, 76.4 ± 54.7, 82.0 ± 50.5, 95.4 ± 57.7) and SCNA (89.1 ± 50.8, 98.5 ± 52.9 and 111.1 ± 59.3) was observed 60 s, 40 s and 20 s, respectively, prior to VT/VF (p<0.001 for both).
Conclusions: SCNA may be used as a surrogate of SGNA in detecting elevated sympathetic tone that triggers VT and VF in ambulatory dogs.
Figure: Both stellate ganglion nerve activity and subcutaneous nerve activity are present prior to the onset of non-sustained ventricular tachycardia on a simultaneously recorded electrocardiogram (ECG).
- © 2013 by American Heart Association, Inc.