Scar Tissue Ablation
Chronic inflammation and atrial re-modeling lead to areas of fibrosis and scar tissue generation, which serve as substrates for AF. Targeting these areas with either voltage mapping or guided by magnetic resonance images (MRI) has been proposed as an adjunctive strategy. A meta-analysis by Blandino et al. (48) showed that ablation of low voltage areas (LVA) in addition to PVI had a significantly improved freedom from AF at a median follow-up of 17 months.
In contrast, two recent RCTs failed to show any difference in outcomes with MRI-guided fibrosis ablation (49,50)However, in patients with low grade fibrosis (grade I or II) PVI + fibrosis ablation led to a reduction in atrial arrhythmia recurrence (51). Another unique approach called box isolation of fibrotic substrates (BIFA) was successfully tested by Kottkamp et al. (52). Fibrotic areas were identified with voltage mapping and targeted with box isolation and freedom from AF was achieved in 72.2 % of those patients. (Figure 6)