Ablation of atrial fibrillation sources identified through sequential high-density mapping: in silico comparison against anatomy-based approaches

Figures

• 

  Figure 1. Conventional and source-based ablation protocols. Conventional anatomy-based ablations included PVI and PVI + posterior wall isolation (box) ablation. These strategies were compared with source ablation based on a recently proposed high-density sequential mapping strategy combined with PVI (summarized in the highlighted box).16 AF re-initiation attempts were performed by incrementally pacing 20 locations in the atria. This process was only required once for conventional ablations, while it was performed after each source ablation step until no AF was initiated after the pacing protocol. AF initiation rates were compared with control simulations without any ablation. AF, atrial fibrillation; EGMs, electrograms; PVI, pulmonary vein isolation.

• 

  Figure 2. The AF and MRAT initiation rates for scenarios without fibrosis (1–3). Conventional ablation approaches (A) did not completely reduce AF inducibility, in contrast to source ablations (B). A maximum of three rounds of induction attempts followed by source ablations (denoted as R1–R3), tracking sources in ≤6 AF episodes, were necessary to fully prevent AF inducibility. An example is shown for Scenario 1: AF episodes induced after PVI (C, top) and after the first round of source ablations (C, bottom) guided the placement of the ablation lines displayed in (D). No AF was initiated after the second round of source ablations. Views: PA, postero-anterior; AP, antero-posterior; LS, left septal; RS, right septal; RV, right view. AF, atrial fibrillation; MRAT, macro-re-entrant atrial tachycardia; PVI, pulmonary vein isolation.

• 

  Figure 3. AF and MRAT initiation rates for scenarios with fibrosis (4–7). The AF inducibility was still ≥40% after PVI without or with box ablation (A). In contrast, source ablations prevented AF initiation after a maximum of four ablation rounds, denoted as R1–R4 (B). To achieve these outcomes, source tracking was performed in ≤16 AF episodes. An example is shown for Scenario 4: AF episodes induced after PVI (C, top) and after the first round of source ablations (C, bottom) guided the placement of the ablation lines displayed in (D). No AF was initiated after the second round of source ablations. Views: PA, postero-anterior; AP, antero-posterior; LS, left septal; RS, right septal; RV, right view. AF, atrial fibrillation; MRAT, macro-re-entrant atrial tachycardia; PVI, pulmonary vein isolation.

• 

  Figure 4. Ablated and isolated area per ablation strategy. (A) and (B) show ablated areas for all strategies in the LA and RA, respectively. Scenarios without fibrosis are shown on the left side, while those with fibrosis are on the right side. (C) and (D) show the electrically isolated areas in each scenario for the LA and RA, respectively. The ablated and isolated areas corresponding to PVI are shown in the labelled boxes, while the percentages of the LA ablated and isolated with box ablation in each anatomy are depicted with dashed lines. Areas ablated when targeting the tracked sources are shown on top of PVI. The median MRAT ablation was added on top of source ablation in order to completely prevent tachyarrhythmias in the models (Section "Ablation of MRAT circuits after AF termination"). Whiskers display the maximum and minimal ablated areas to prevent MRATs in each scenario. LA, left atrium; MRAT, macro-re-entrant atrial tachycardia; PVI, pulmonary vein isolation; RA, right atrium.