Intrinsic cardiac nerve activity and paroxysmal atrial tachyarrhythmia in ambulatory dogs.
BACKGROUND
Little is known about the relationship between intrinsic cardiac nerve activity (ICNA) and spontaneous arrhythmias in ambulatory animals.


RESULTS
We implanted radiotransmitters to record extrinsic cardiac nerve activity (ECNA; including stellate ganglion nerve activity and vagal nerve activity) and ICNA (including superior left ganglionated plexi nerve activity and ligament of Marshall nerve activity) in 6 ambulatory dogs. Intermittent rapid left atrial pacing was performed to induce paroxysmal atrial fibrillation or atrial tachycardia. The vast majority (94%) of ligament of Marshall nerve activity were preceded by or coactivated with ECNA (stellate ganglion nerve activity or vagal nerve activity), whereas 6% of episodes were activated alone without concomitant stellate ganglion nerve activity or vagal nerve activity. Paroxysmal atrial fibrillation and atrial tachycardia were invariably (100%) preceded (<5 seconds) by ICNA. Most paroxysmal atrial tachycardia events (89%) were preceded by ICNA and sympathovagal coactivation, whereas 11% were preceded by ICNA and stellate ganglion nerve activity-only activation. Most paroxysmal atrial fibrillation events were preceded only by ICNA (72%); the remaining 28% were preceded by ECNA and ICNA together. Complex fractionated atrial electrograms were observed during ICNA discharges that preceded the onset of paroxysmal atrial tachycardia and atrial fibrillation. Immunostaining confirmed the presence of both adrenergic and cholinergic nerve at ICNA sites.


CONCLUSIONS
There is a significant temporal relationship between ECNA and ICNA. However, ICNA can also activate alone. All paroxysmal atrial tachycardia and atrial fibrillation episodes were invariably preceded by ICNA. These findings suggest that ICNA (either alone or in collaboration with ECNA) is an invariable trigger of paroxysmal atrial tachyarrhythmias. ICNA might contaminate local atrial electrograms, resulting in complex fractionated atrial electrogram-like activity.
Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine,1801 N Capitol Avenue, Indianapolis, IN 46202, USA.
Eue-Keun
EK
Choi
Mark J
MJ
Shen
Seongwook
S
Han
Daehyeok
D
Kim
Samuel
S
Hwang
Sameh
S
Sayfo
Gianfranco
G
Piccirillo
Kyle
K
Frick
Michael C
MC
Fishbein
Chun
C
Hwang
Shien-Fong
SF
Lin
Peng-Sheng
PS
Chen
D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology*; D004195:Disease Models, Animal; D004285:Dogs; D015716:Electrocardiography, Ambulatory; D022062:Electrophysiologic Techniques, Cardiac; D055724:Electrophysiological Phenomena / Q000502:physiology*; D006321:Heart / Q000294:innervation*; D006325:Heart Atria / Q000503:physiopathology*; D008297:Male; D013233:Stellate Ganglion / Q000503:physiopathology; D013614:Tachycardia, Paroxysmal / Q000503:physiopathology*; D014630:Vagus Nerve / Q000503:physiopathology