Difference in the maintenance mechanism of atrial fibrillation perpetuated after pulmonary vein isolation between paroxysmal and persistent atrial fibrillation: Effects of subsequent stepwise ablation

BackgroundNeither the atrial fibrillation (AF) maintenance mechanism after pulmonary vein isolation (PVI) nor the mechanism of AF termination via stepwise ablation is clearly understood.MethodsAmong 226 consecutive AF patients (154 paroxysmal (P-AF) and 72 persistent AF (Per-AF) patients), left atrial endocardial non-contact mapping was performed after PVI in the initial 10 P-AF and 16 Per-AF patients to define the AF maintenance mechanism. Subsequently, effect of stepwise catheter ablation (linear roof lesion and complex fractionated atrial electrogram (CFAE) following PVI) was evaluated in all patients.ResultsAfter PVI, AF was maintained by the activation around isolated PV/mitral annulus, focal discharge and disorganized activations mostly observed over residual CFAE region (pivoting activation, wave break and fusion). CFAE region in P-AF was smaller than Per-AF after PVI (1.6 ± 2.1 vs. 7.7 ± 2.5 cm2, p < 0.0001). The frequency of pivoting activation, wave break and fusion in P-AF were lower than those in Per-AF (1.9 ± 2.0 vs. 11.8 ± 5.0 times/s; p < 0.0001, 0.1 ± 0.3 vs. 3.6 ± 2.5 times/s; p < 0.001, 5.8 ± 3.6 vs. 9.8 ± 3.2 times/s; p < 0.01). AF termination was more frequent in P-AF than Per-AF (94.8% vs 81.9%, p = 0.0019). AF termination by PVI alone was more frequent in P-AF than Per-AF (85.6% vs. 18.6%, p < 0.0001). However, AF termination via roof line and/or CFAE ablation was less frequent in P-AF than Per-AF (14.4 vs. 81.4%, p < 0.0001).ConclusionsDisorganized activations after PVI, more prominent in Per-AF, were associated with residual CFAE region. Most P-AF was terminated by PVI alone, however additional roof line lesion and CFAE ablation were necessary to terminate Per-AF, consistent with mapping results.