Optimized lesion size index (o‐LSI): A novel predictor for sufficient ablation of pulmonary vein isolation

Abstract Background Although the lesion size index (LSI) has been well established, it is sometimes difficult to achieve first‐pass pulmonary vein isolation (PVI) and to avoid acute pulmonary vein reconnections, even with LSI‐guided procedures. The purpose of this study was to assess the predictive accuracy of a novel parameter, the optimized lesion size index (o‐LSI), to perform PVI. Methods The voltage maps created by the Advisor™ high‐density (HD) grid catheter before PVI in 35 atrial fibrillation (AF) patients were examined for an association between the voltage amplitude and insufficient ablation sites (IAS), which were defined as either (i) spontaneous reconnection sites, (ii) dormant PV conduction sites unmasked with 20 mg of adenosine triphosphate disodium hydrate (ATP) injection, or (iii) PV‐LA gap sites after the initial PVI. Results IAS was observed in 25/1417 of the total ablation sites. IAS was significantly associated with higher bipolar voltage areas (4.20 ± 2.68 vs 2.43 ± 1.93 mV, P