Lesion index: a novel guide in the path of successful pulmonary vein isolation

PurposePrevious studies indicate force time integral (FTI) as a radiofrequency (RF) lesion quality marker, while not considering power supply. Tacticath Quartz catheter provides Lesion index (LSI), a lesion quality marker derived by contact force (CF), power supply, and RF time combined. Our aim is to assess LSI and FTI correlation and a LSI-related cutoff of atrial fibrillation (AF) recurrences 12months after pulmonary vein isolation (PVI).MethodsWe retrospectively enrolled 37 patients who underwent RF ablation using Tacticath Quartz catheter. AF recurrence rate was evaluated 3, 6, and 12months after PVI procedure.ResultsAF recurrence was detected in 32% of patients. FTI mean value was significantly lower in left superior pulmonary vein (LSPV: 25686gs vs 329 +/- 117gs, p=0.05) and right inferior pulmonary vein (RIPV: 253 +/- 128gs vs 394 +/- 123gs p=0.006) in patients with AF recurrences; no significant differences were found in right superior pulmonary vein (RSPV) and left inferior pulmonary vein (LIPV). LSI instead was significantly higher for all veins in patients without AF recurrences: LSPV (5.2 +/- 0.7 vs 4.6 +/- 0.8, p=0.03), LIPV (5.0 +/- 0.8 vs 4.5 +/- 0.6, p=0.04), RSPV (5.5 +/- 0.6 vs 5.1 +/- 0.6, p=0.05), and RIPV (5.5 +/- 0.7 vs 4.7 +/- 0.8, p=0.006). Receiver operator characteristic curve suggests 5.3 as LSI overall cutoff value predicting freedom from disease at 1-year follow-up.ConclusionsOur preliminary data suggest that a LSI mean value higher than 5.3 can be considered a good predictor of AF freedom at 1-year follow-up.