In Vitro Validation of the Lesion Size Index to Predict Lesion Width and Depth After Irrigated Radiofrequency Ablation in a Porcine Model

Abstract

In this in vitro model, FTI and LSI predicted RF lesion dimensions, whereas power and CF did not. The LSI predictive value was higher than that of FTI. Steam pops occurred only using high ablation power levels, regardless of the targeted LSI.

Optimal lesion size index to prevent conduction gap during pulmonary vein isolation

“…In an in vitro model, the predictive value of LSI for lesion size was reported to be higher than that of FTI; however, the superiority of LSI for predicting the residual gap or DC was not validated in our human study. This discrepancy may possibly be explained by several factors.…”

“…The LSI is a novel index that can help predict the size of the lesion created by RF application. LSI is derived from a mathematical expression that incorporates CF, impedance, power, and duration of RF application . LSI represents an improvement over FTI in several respects .…”

“…To characterize the effect of CF applied over time, the system automatically detects the ablation time and calculates FTI and LSI only when the ablation catheter stays within the confined area. FTI was defined as the total CF integrated over the time of RF delivery, and the formula of LSI was derived from a mathematical expression that incorporates CF, impedance, power, and duration of RF application . AutoMark settings for filter thresholds in this study were as follows: for catheter position stability, the minimum marker time was 3 seconds, the marker spacing was 3 mm, and the away time was 8 seconds.…”

“…Several studies have demonstrated a correlation between FTI and lesion size during RF application; furthermore, FTI was shown to predict lesion size and steam pop occurrence in a beating canine heart . The lesion size index (LSI) is another novel multiparametric index that incorporates time, power, CF, and impedance data recorded during RF ablation in a weighted formula that describes ablation biophysics . However, the optimal LSI for a successful pulmonary vein isolation (PVI) procedure has not been verified.…”

High‐power short‐duration versus standard radiofrequency ablation: Insights on lesion metrics

“…FTI is a lesion metric that is included in multiple electroanatomic mapping platforms, while ablation index (AI) (Biosense Webster) is a proprietary algorithm combining CF, RF application duration, and power. AI calculation was derived in previous studies and is based on a complex formula incorporating RF power, RF duration, and CF, and lesion metric indices have been shown to correlate with lesion dimensions . Previous in vivo studies have suggested targeting AI values from 400 to 500 to create durable lesions in pulmonary vein isolation (PVI) procedures.…”