Ganglionated plexi as neuromodulation targets for atrial fibrillation

Abstract

The autonomic nervous system plays an important role in the genesis of atrial fibrillation and is one of the candidate targets for atrial fibrillation therapy. This review focuses on the role of the autonomic nervous system in atrial fibrillation development and discusses the results of the ganglionated plexi catheter and surgical ablation in preclinical and clinical studies. The heart is innervated by the extrinsic and intrinsic autonomic nervous systems. The intrinsic autonomic nervous system consists of multiple ganglionated plexi and axons, which innervate the neighboring atrial myocardium and control their electrophysiological properties. Abnormal autonomic innervation has been observed in an animal model of atrial fibrillation and in humans. Direct recordings of autonomic nerve activity in canine models showed that atrial tachyarrhythmia episodes were invariably preceded by intrinsic cardiac autonomic nerve activity, thus supporting the importance of intrinsic cardiac autonomic nerve activity as the triggers for atrial tachyarrhythmia. Targeting ganglionated plexi with catheter ablation improves the outcomes of paroxysmal atrial fibrillation ablation in addition to pulmonary vein antrum isolation. Ablation of ganglionated plexi alone without pulmonary vein isolation is also useful in controlling paroxysmal atrial fibrillation in some patients. However, surgical ganglionated plexi ablation in patients with a large left atrium, persistent atrial fibrillation and/or a history of prior catheter ablation does not result in additional benefits. These different outcomes suggest that ganglionated plexi ablation is effective in managing patients with paroxysmal atrial fibrillation, but its effects in patients with persistent atrial fibrillation and advanced atrial diseases might be limited.

A square root pattern of changes in heart rate variability during the first year after circumferential pulmonary vein isolation for paroxysmal atrial fibrillation and their relation with long‑term arrhythmia recurrence

“…Autonomic nervous system and atrial fibrillation The LA contains 4 GPs, which are located at the epicardial aspect of the LA-PV junction. 1 The GPs include both adrenergic and cholinergic nerve fibers that control cardiac A reduction of 25 ms or lower for Δ SDNN at 3 months post-CA was associated with an increase in the prevalence of LRAF from 19.6% to 41% in the ERAF -free patients (n = 85) and from 130 120 110 100 90 80 70 60 50 40 Mean HR, bpm 1400 1300 1200 1100 1000 900 800 700 600 500 Mean R- and 2 denervation after CA and subsequent gradual reinnervation. Of note, despite partial reinnervation after 3 to 6 months after ablation, the HRV markers of the overall sympatho -vagal balance (SDNN, SDSD, pNN50, and mean R -R interval) and more specific HRV indices of parasympathetic activity (rMSSD and LF / HF ratio) were still significantly reduced at 1 year after CPVI in the AF -free patients but not in those with the recurrence of arrhythmia.…”

“…6 Thus, in younger patients with no evidence of structural heart disease, vagal predominance promotes the triggered PV activity associated with afterdepolarization, shortens the PV refractoriness and AF cycle length, resulting in the inducibility and / or maintenance of AF. 1,11 Outcomes of denervation and ablation for atrial fibrillation The GP ablation led to a vagal response (ie, bradycardia and hypotension) during RF current application, and subsequently to noninducibility of vagally mediated AF. 1 Several studies reported a significant change of the HRV parameters after CPVI, indicating a remarkable parasympathetic withdrawal.…”

“…1,11 Outcomes of denervation and ablation for atrial fibrillation The GP ablation led to a vagal response (ie, bradycardia and hypotension) during RF current application, and subsequently to noninducibility of vagally mediated AF. 1 Several studies reported a significant change of the HRV parameters after CPVI, indicating a remarkable parasympathetic withdrawal. 3,[6][7][8]12,13 The GPs in the LA are located close to the selected CPVI ablation trajectory 1 and, therefore, are commonly collaterally damaged during the ablation.…”

“…2 The CPVI procedure may affect the cardiac autonomic nervous activity through (un)intentional injury of the left atrial (LA) parasympathetic ganglia (ganglionated plexi [GP]) in the proximity of the PVs by radiofrequency (RF) current. 1,3 INTRODUCTION Autonomic nervous system significantly modulates the triggers for atrial fibrillation (AF) within the pulmonary veins (PVs). 1 Circumferential pulmonary vein isolation (CPVI) is the mainstay of catheter ablation (CA) for paroxysmal AF (PAF); however, arrhythmia reoccurs in up to 30% to 50% of exercise testing, and 24-hour Holter monitoring.…”

“…1,3 INTRODUCTION Autonomic nervous system significantly modulates the triggers for atrial fibrillation (AF) within the pulmonary veins (PVs). 1 Circumferential pulmonary vein isolation (CPVI) is the mainstay of catheter ablation (CA) for paroxysmal AF (PAF); however, arrhythmia reoccurs in up to 30% to 50% of exercise testing, and 24-hour Holter monitoring. The study was approved by the institutional ethics committee, and all patients signed informed consent to participate in the study.…”