Intrinsic cardiac nerve activity invariably preceded (100%) all episodes of paroxysmal atrial tachycardia and atrial fibrillation in ambulatory dogs.
Does intrinsic cardiac nerve activity trigger paroxysmal atrial tachyarrhythmias in ambulatory dogs?
Intrinsic cardiac nerve activity invariably precedes and likely triggers paroxysmal atrial tachyarrhythmias in an ambulatory dog model.
BACKGROUND: Little is known about the relationship between intrinsic cardiac nerve activity (ICNA) and spontaneous arrhythmias in ambulatory animals. METHODS AND 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.
Choi et al. (Tue,) conducted a other in Paroxysmal atrial tachyarrhythmia (n=6). Intermittent rapid left atrial pacing was evaluated on Proportion of paroxysmal atrial fibrillation and atrial tachycardia episodes preceded by intrinsic cardiac nerve activity. Intrinsic cardiac nerve activity invariably preceded (100%) all episodes of paroxysmal atrial tachycardia and atrial fibrillation in ambulatory dogs.