Effective Ablation Settings That Predict Chronic Scar After Left Atrial Ablation

OBJECTIVES:The goal of this study was to find effective parameters that can be used in real-time that result in chronic scar verified by left atrial (LA) late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). BACKGROUND:Automated annotation can be a useful tool while ablating in tagging areas that will result in scar, but the effective settings that best predict chronic scar are still unknown. METHODS:Patients underwent pulmonary vein isolation using a CARTO3 mapping system with a VISITAG Module and 3-month post-ablation LGE-CMR. The electroanatomical map (EAM) was used to retrospectively tag ablated areas with 5 different parameters: catheter stability; stability duration; force over time; minimum contact force; and impedance drop. The ablation tags in EAM were projected to the 3-month post-ablation LGE-CMR. Tags were divided into 2 groups depending on if they correlated with CMR-based scar tags (STAGs) or nonscar tags (NTAGs); the effective parameters were estimated for the 2 groups at different power levels. RESULTS:This study assessed 70 consecutive patients and 28,939 ablation tags. Ablation time and force time integral (FTI) were significantly larger in the STAG group. Mean contact force, change of catheter tip temperature, and impedance were not significantly different between STAGs and NTAGs. The minimum ablation time and FTI to make durable scar lesions were 17.6, 13.6, and 11.0 s and 226.1, 187.4, and 161.4 g at 25, 35, and 50 W, respectively. CONCLUSIONS:Minimum ablation time and FTI values are critical parameters that determine durable atrial scar creation and their minimum values vary with the ablation power setting.