Epicardial and Endocardial Validation of Conduction Block After Thoracoscopic Epicardial Ablation of Atrial Fibrillation.

Epicardial bidirectional conduction block in the PVs and the box lesion corresponded well with endocardial bidirectional conduction block. Conduction block predictions by changes in tissue conductance failed in few cases compared to block confirmation. This emphasizes that tissue conduction measurements can provide a rough indication of lesion effectiveness but needs endpoint confirmation by either epicardial or endocardial block testing.