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

Abstract

Background Ganglionated plexuses (GPs) are implicated in atrial fibrillation (AF). Endocardial high‐frequency stimulation (HFS) delivered within the local atrial refractory period can trigger ectopy and AF from specific GP sites (ET‐GP). The aim of this study was to understand the role of ET‐GP ablation in the treatment of AF. Methods Patients with paroxysmal AF indicated for ablation were recruited. HFS mapping was performed globally around the left atrium to identify ET‐GP. ET‐GP was defined as atrial ectopy or atrial arrhythmia triggered by HFS. All ET‐GP were ablated, and PVs were left electrically connected. Outcomes were compared with a control group receiving pulmonary vein isolation (PVI). Patients were followed‐up for 12 months with multiple 48‐h Holter ECGs. Primary endpoint was ≥30 s AF/atrial tachycardia in ECGs. Results In total, 67 patients were recruited and randomized to ET‐GP ablation (n = 39) or PVI (n = 28). In the ET‐GP ablation group, 103 ± 28 HFS sites were tested per patient, identifying 21 ± 10 (20%) GPs. ET‐GP ablation used 23.3 ± 4.1 kWs total radiofrequency (RF) energy per patient, compared with 55.7 ± 22.7 kWs in PVI (p = <.0001). Duration of procedure was 3.7 ± 1.0 and 3.3 ± 0.7 h in ET‐GP ablation group and PVI, respectively (p = .07). Follow‐up at 12 months showed that 61% and 49% were free from ≥30 s of AF/AT with PVI and ET‐GP ablation respectively (log‐rank p = .27). Conclusions It is feasible to perform detailed global functional mapping with HFS and ablate ET‐GP to prevent AF. This provides direct evidence that ET‐GPs are part of the AF mechanism. The lower RF requirement implies that ET‐GP targets the AF pathway more specifically.

Ectopy-triggering ganglionated plexuses ablation to prevent atrial fibrillation: GANGLIA-AF study

“… 11 The success rate of GPA was slightly improved from our previous pilot study, which also primarily targeted ET-GPs without PVI. 6 Our success rate for PVI was similar to those reported in large trials of RF ablation for paroxysmal AF. 1 , 2 …”

“…This was in anticipation for a high rate of crossover from the GPA group as experienced in our previous pilot study. 6 Afterward, randomization was switched to 1:1 in blocks of 10 for the remainder of the recruitment. Patients and their cardiologists providing their usual care were blinded to their randomization.…”

“…We aimed to test up to 80 HFS sites, as this was usually sufficient to cover all the left atrial surface available for testing as in our previous pilot study. 6 The exact number of HFS sites tested varied between patients, depending on the size of their left atrium and the procedure time.…”

“…This was also reproduced in clinical studies. 6 , 8 , 9 In this study, for our synchronized HFS protocol, the left atrium was paced at high output (10 V) from the ablation catheter during sinus rhythm (SR) to check for atrial capture and to exclude ventricular capture. Then, we delivered short bursts of HFS trains (10 V, 80 ms duration, 40 Hz) coupled to each paced stimulus to ensure that HFS was delivered within the local atrial refractory period.…”

“… 4 , 5 Subsequently, we performed a randomized controlled single-center pilot study to test the feasibility of locating and ablating GPs using an endocardial approach and showed that selective GP ablation (GPA) was able to prevent AF without the need for PVI. 6 We made modifications to this pilot protocol and tested the hypothesis that selective GPA could be superior to PVI in a larger, multicenter, randomized controlled setting.…”