Spontaneous stellate ganglion nerve activity and ventricular arrhythmia in a canine model of sudden death.
BACKGROUND
Little information is available on the temporal relationship between instantaneous sympathetic nerve activity and ventricular arrhythmia in ambulatory animals.


OBJECTIVE
The purpose of this study was to determine if increased sympathetic nerve activity precedes the onset of ventricular arrhythmia.


METHODS
Simultaneous continuous long-term recording of left stellate ganglion (LSG) nerve activity and electrocardiography was performed in eight dogs with nerve growth factor infusion to the LSG, atrioventricular block, and myocardial infarction (experimental group) and in six normal dogs (control group).


RESULTS
LSG nerve activity included low-amplitude burst discharge activity (LABDA) and high-amplitude spike discharge activity (HASDA). Both LABDA and HASDA accelerated heart rate. In the experimental group, most ventricular tachycardia (86.3%) and sudden cardiac death were preceded within 15 seconds by either LABDA or HASDA. The closer to onset of ventricular tachycardia, the higher the nerve activity. The majority of HASDA was followed immediately by either ventricular arrhythmia (21%) or QRS morphology changes (65%). HASDA occurred in a circadian pattern. HASDA occurred twice as often in the experimental group than in the control group. Electrical stimulation of LSG increased transmural heterogeneity of repolarization (Tpeak-end intervals) and induced either ventricular tachycardia or fibrillation in the experimental group but not in the control group. Immunohistochemical studies revealed increased synaptogenesis and nerve sprouting in the LSG in the experimental group.


CONCLUSIONS
Two distinct types of LSG nerve activity (HASDA and LABDA) are present in the LSG of ambulatory dogs. The majority of malignant ventricular arrhythmias are preceded by either HASDA or LABDA, with HASDA particularly arrhythmogenic.
Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA.
Shengmei
S
Zhou
Byung-Chun
BC
Jung
Alex Y
AY
Tan
Vinh Quang
VQ
Trang
Ghassan
G
Gholmieh
Seong-Wook
SW
Han
Shien-Fong
SF
Lin
Michael C
MC
Fishbein
Peng-Sheng
PS
Chen
Lan S
LS
Chen
D000818:Animals; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D004285:Dogs; D004558:Electric Stimulation; D004562:Electrocardiography; D004594:Electrophysiology; D006339:Heart Rate; D023421:Models, Animal; D013233:Stellate Ganglion / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D017180:Tachycardia, Ventricular / Q000209:etiology / Q000503:physiopathology*; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000209:etiology / Q000503:physiopathology*