Co-Author(s):
Xin Li, BEng, MSc, PhD - Lecturer, University of Leicester
Sidhu Bharat, MBChB, MRCP - Cardiology Research Fellow, University of Leicester
Zakariyya Vali, MBChB, MRCP - Clinical Research Fellow, University of Leicester
Gavin Chu, MB BChir, MA(Cantab), MRCP(UK) - Cardiology Research Fellow, University of Leicester
Peter Stafford, MB BS, MD, FRCP - Consultant Cardiologist, University Hospitals of Leicester NHS Trust
Michela Masè, MSc, PhD - Post-doctoral Fellow, University of Trento
Flavia Ravelli, PhD - University of Trento
Fernando Schlindwein, BEng (1st class Hons), MSc (distinction), CEng, SFHEA, PhD, DSc - Reader, University of Leicester
G. André Ng, MB ChB (commendation), MRCP (UK), PhD, FRCP, FESC, FHEA, FEHRA - Professor of Cardiac Electrophysiology, University of Leicester
University of Leicester
Glenfield Hospital
Introduction | Objectives: Ablation to treat persistent atrial fibrillation (persAF) remains sub-optimal. Understanding the underlying electrophysiology (EP) of patients that had persAF terminated following ablation is important to identify minimum and optimal set of points for ablation. In the present work, we aimed to understand the EP behaviours of patients who responded differently to additional substrate ablation measured by AF cycle length (AF-CL) changes.
Methods: 11 persAF patients (AF history 57.3 ± 37.5 mo) undergoing pulmonary vein isolation followed by substrate ablation guided by NavX (Abbott Laboratories) were identified. All patients had AF terminated to either sinus rhythm or to an organized arrhythmia during substrate ablation. AF-CL was measured in the coronary sinus (10 beats average) before and after each cluster of ablation. The patients were divided in two groups based on AF-CL changes vs. baseline following substrate-guided ablation prior to AF termination: group 1 represents patients with 10% AF-CL increase or longer (Fig 1A); group 2 represents patients with less than 10% increase in AF-CL (Fig 1B). 956 bipolar atrial electrograms (AEGs; 5 s, band-pass filtered 30-300 Hz, 50 Hz notch filtered) used to guide ablation with NavX were exported. Attributes were extracted from the AEGs to characterize different EP aspects of each group: NavX’s CFE-Mean, CARTO’s interval confidence level (ICL), wave similarity index (WSi) and organization index (OI).
Results: 1 patient (patient 4) had AF termination during first cluster ablation. Group 1 (6 patients) showed shorter AF-CL when compared to group 2 (4 patients) (Fig 2A). Group 1 needed less ablation to convert AF compared to group 2 (Fig 2B). Additionally, group 1 showed more fractionated AEGs, with lower CFE-Mean and higher ICL (Fig 3A and 3B), lower WSi and OI (Fig 3C and 3D).
Conclusions: AF-CL changes were more evident in patients with shorter baseline AF-CL. These patients, however, needed less ablation to terminate AF despite seemingly more complex arrhythmia. These counterintuitive results may suggest underlying diversity in mechanisms and highlight the need to tailor ablation according to patient characteristics in order to minimize ablation burden.
AFS 2021-52