The Effective Contact Force to Minimize Edema Relative to Chronic Lesion Formation During Radiofrequency Ablation in Ventricular Wall.

Radiofrequency (RF) ablation results in creation of acute edema which can lead to temporary disruption of electrical propagation.The goal of this study was to find the effective contact force (CF) to minimize edema formation in comparison to the lesion size.Ventricular RF lesions (n = 49) were created by a CF-sensing catheter in a canine model (n = 10) with varying force for 30 seconds. Animals underwent T2-weighted (T2w) and late gadolinium enhancement MRI (LGE-MRI) immediately after ablation and at 12 weeks. Acute LGE lesion volume, acute edema, and chronic LGE lesion volume were measured. Acute edema/acute LGE lesion volume ratio was used to divide the lesions into two groups.Mean edema/lesion volume ratio was 5.0 ± 2.8. The lesions were divided into greater edema group (n = 8) and smaller edema group (n = 41) based on a cutoff edema/lesion volume ratio. When comparing the two groups, the CF and force time integral (FTI) were significantly lower in the greater edema group. There was no difference in catheter power setting, tip temperature change, impedance drop, and bipolar electrogram voltage change. Acute LGE volume and chronic lesion depth were significantly smaller in the greater edema group. Moreover, receiver-operator characteristic curve for the smaller edema lesion group showed that the most discriminant cutoff values for CF and FTI were 12.4 g and 584 gs, respectively.To minimize edema size while still forming permanent lesions, ablation should be performed with FTI > 584 gs or CF > 12.4 g.