Abstract 739: Epicardial Ablation And Isolation Of Ganglionated Plexi In Refractory Persistent Atrial Fibrillation: Does It Really Matter?
Background. Major epicardial ganglionated plexi (GP) could be important targets during atrial fibrillation (AF) ablation (ABL). Still controversies exist regarding the role of GP and vagal denervation.
Aim: identify and target GP by epicardial stimulation during thoracoscopic pulmonary vein (PV) isolation and study the effect of ABL and isolation of these GP in refractory persistent AF patients (pts).
Methods. Seventeen consecutive pts with refractory persistent AF (87% men, age 59±9 y, BMI=28±5 kg/m2) underwent right lateral thoracoscopic epicardial PV and major GP ABL and isolation using microwave (MW) energy (FLEX 10 AFx System Boston Scientific Corp.). Mapping of GP was tested using high frequency stimulation (HFS: 20 Hz, 2 ms, 20 mA) during AF. Any effect or significant response on ventricular rate, defined as ≥50% increase in R-R interval during HFS in AF, was recorded.
Results. Mean duration of AF, without sinus rhythm (SR) was 29±40 months (M). Mean procedure duration, placement of MW antenna and energy applications (65 W, 120 s) was respectively 122±24, 17±7 and 37±7 minutes. Before energy application, HFS of GP in pts without prior endocardial ABL induced a modest degree of vagal response in 10 pts (58.8%) of cases. Anterior right GP (ARGP) was involved in all these 10 pts. The inferior right GP (IRGP) and the left superior GP (LSGP) were responsive in respectively 3 and 5 pts. The left inferior GP could not be reached by right thoracoscopic approach. In 5 pts of whole group, the response was considered significantly positive: 5 ARGP, 2 IRGP and 3 LSGP. No more GP responses were present after MW applications. Of note, 3 pts who underwent prior endocardial lasso catheter ABL had complete absence of response to HFS. All pts. with long-lasting AF had a negative response to HFS. At discharge 53% of pts were in SR; only 34% of these pts had a positive vagal response at HFS. At first follow-up at ±3.4 M, 60% of pts were still in SR.
Conclusion. Epicardial GP ABL and isolation by right thoracoscopy in persistent AF pts seems feasible and is associated with reliably successful identification of GP and a good clinical success rate. The absence of response of GP to HFS in long-lasting AF and why RAGP is most responsive to HFS has to be further evaluated.