The ectopy-triggering ganglionated plexuses in atrial fibrillation

Abstract

Background Epicardial ganglionated plexuses (GP) have an important role in the pathogenesis of atrial fibrillation (AF). The relationship between anatomical, histological and functional effects of GP is not well known. We previously described atrioventricular (AV) dissociating GP (AVD-GP) locations. In this study, we hypothesised that ectopy triggering GP (ET-GP) are upstream triggers of atrial ectopy/AF and have different anatomical distribution to AVD-GP. Objectives We mapped and characterised ET-GP to understand their neural mechanism in AF and anatomical distribution in the left atrium (LA). Methods 26 patients with paroxysmal AF were recruited. All were paced in the LA with an ablation catheter. High frequency stimulation (HFS) was synchronised to each paced stimulus for delivery within the local atrial refractory period. HFS responses were tagged onto CARTO™ 3D LA geometry. All geometries were transformed onto one reference LA shell. A probability distribution atlas of ET-GP was created. This identified high/low ET-GP probability regions. Results 2302 sites were tested with HFS, identifying 579 (25%) ET-GP. 464 ET-GP were characterised, where 74 (16%) triggered ≥30s AF/AT. Median 97 (IQR 55) sites were tested, identifying 19 (20%) ET-GP per patient. >30% of ET-GP were in the roof, mid-anterior wall, around all PV ostia except in the right inferior PV (RIPV) in the posterior wall. Conclusion ET-GP can be identified by endocardial stimulation and their anatomical distribution, in contrast to AVD-GP, would be more likely to be affected by wide antral circumferential ablation. This may contribute to AF ablation outcomes.

Targeting the ectopy‐triggering ganglionated plexuses without pulmonary vein isolation prevents atrial fibrillation

“…Most ET‐GP were anatomically located around the PV antra, the roof, and down the midline of the anterior wall 15 . Malcolme‐Lawes et al 18 previously demonstrated that PVI can abolish the PV ectopy triggering effect of ET‐GP in patients with AF.…”

“…If this occurred, we repeated HFS and reduced the duration of HFS until no further local capture was evident. A “positive” response to synchronized HFS included single atrial ectopy, few beats of atrial ectopy, atrial tachycardia or AF 15 . These positive responses were tagged as “ET‐GP” sites on the CARTO geometry.…”

“…This technique paces the atrium at a fixed rate, and 100‐ms duration of HFS is delivered at 10–14 V, 20 Hz (synchronized HFS). This avoids direct myocardial capture and has been shown to trigger PV and non‐PV ectopy that can lead to AF 15 . We previously mapped these ectopy‐triggering GPs (ET‐GP) which were anatomically and functionally distinct from AVD‐GP 16 .…”

Very Long-term Outcome after Linear vs. Electrogram-guided Ablation for Persistent Atrial Fibrillation: A Propensity Score-matched Analysis.

“…22 Roof and MI lines have a potential benefit for alteration of AF wavelet propagation and elimination of spectral components by complete bidirectional block of linear lesions. In addition, these linear lesions lead to reduction of excitable LA myocardial mass, the attenuation of vagal innervation 23 and elimination of non-PV foci, especially relating to the ligament of Marshall. 24,25 Although the endpoint of linear ablation is clear, establishing linear block, especially during MI line ablation, maybe challenging.…”

Very Long-term Outcome after Linear vs. Electrogram-guided Ablation for Persistent Atrial Fibrillation: A Propensity Score-matched Analysis

“…22 Roof and MI lines have a potential bene t for alteration of AF wavelet propagation and elimination of spectral components by complete bidirectional block of linear lesions. In addition, these linear lesions lead to reduction of excitable LA myocardial mass, the attenuation of vagal innervation 23 and elimination of non-PV foci, especially relating to the ligament of Marshall. 24,25 Although the endpoint of linear ablation is clear, establishing linear block, especially during MI line ablation, maybe challenging.…”