Introduction:
Pulmonary vein (PV) isolation forms the cornerstone of any ablation procedure for atrial fibrillation (AF). There is, however, no uniform strategy how to detect and target left atrial (LA) arrhythmogenic substrate outside the PV antra. Fibrosis that corresponds well to LA low-voltage areas (LVAs) seems to play a key role in AF arrhythmogenesis and might therefore be a suitable target for additional substrate modification (SM).
Objective:
The purpose of this prospective randomized study was to compare a novel technique for SM based on ablation of potentially arrhythmogenic LA LVAs with a standard approach consisting of empiric LA linear ablation.
Methods:
Patients (pts) with symptomatic paroxysmal or persistent AF were randomized to standard (group 1) or personalized (group 2) SM. Circumferential PV isolation was the primary step in both groups. In group 1, pre-defined linear lesions were applied at the LA roof and bottom, respectively, and at the mitral isthmus only in pts with persistent AF. In group 2, targets for SM (i.e. LVAs) were identified by detailed bipolar voltage mapping (BVM) during sinus rhythm irrespective of AF type. Peak-to-peak electrogram amplitudes were defined as “normal” (> 0.5 mV), as “low voltages” (0.2 to 0.5 mV), or as “scar” (< 0.2 mV). LVAs were targeted by tissue homogenization and / or strategic linear lesions. The primary endpoint was freedom from any atrial arrhythmia (i.e. AF, atrial flutter, or atrial tachycardia) > 30 seconds off antiarrhythmic drugs on serial 7-d-Holter ECG recordings after a follow-up period of 12 months.
Results:
In total, 124 ablation-naïve pts (mean age 63 ± 9 years, 62 % male, 49 % with persistent AF) were enrolled in this study. LVAs were present in 18 % of pts with paroxysmal and in 41 % of pts with persistent AF (p<0.05). At the end of the follow-up period, 25 out of 59 pts (42 %) in the conventional group were free from arrhythmia recurrence as compared to 40 out of 59 pts (68 %) in the BVM-guided group (unadjusted log rank p = 0.003).
Conclusion:
Personalized SM guided by endocardial BVM is associated with a higher success rate compared to a conventional approach applying empirical SM based on AF phenotype.
Substrate modification or ventricular tachycardia induction, mapping, and ablation as the first step? A randomized study
