C. Induction thresholds will be compared Post-ablation, AF will again be induced systematically using the same protocol as before, and this threshold will be compared to the pre-ablation one. The threshold will be considered as increased if the post-ablation induction protocol entails a more aggressive pacing protocol (e.g. a protocol with faster pacing [shorter cycle length]). Figure 4 summarizes the workflow for Specific Aim 2.