Mechanistically guided posterior box isolation using pace-capture resting and threshold-adjusted voltage mapping

Durable posterior wall isolation remains challenging in atrial fibrillation (AF) ablation despite its strong mechanistic rationale.1 Large randomized trials have failed to demonstrate incremental benefit when empirical posterior wall ablation is added to pulmonary vein isolation (PVI), suggesting that indiscriminate posterior wall homogenization may not adequately address critical residual conduction pathways.2,3 We evaluated an exploratory, mechanistically guided strategy integrating functional lesion assessment and substrate-based mapping to achieve posterior box isolation (POBI) after PVI.