Abstract Body (Do not enter title and authors here): Background: First pass isolation (FPI) improves freedom from AF, while acute pulmonary vein reconnection (PVR) predicts AF recurrence. There is little data to predict FPI or acute PVR based on individual patient characteristics. Height is a risk factor for incident AF and may be associated with AF recurrence after ablation.

Hypothesis: We hypothesize that patient-specific factors can predict lack of FPI and acute PVR. If such factors are identified and used to modify ablation strategies, FPI will increase and acute PVR will reduce in those undergoing paroxysmal AF ablation.

Methods: Patients were ablated utilizing CARTO3 with THERMOCOOL SMARTTOUCH SF catheters at 50W, 2mm overlapping lesions. A derivation cohort of patients were treated with standard Ablation Index (AI) targets of 450 on anterior and 350 on posterior surfaces. Subsequently, ablation strategies would be modified and outcomes were reassessed.

Results: In the derivation cohort, median height (<172cm vs >172cm) was the strongest predictor of FPI among all variables (age, sex, height, weight, BSA, diabetes, hypertension, sleep apnea, LA size), (B=1.68 p<0.01). When patients were treated with standard AI targets, patients >172cm had reduced FPI (50/107 [47%] vs 67/99 [68%] p<0.01) and increased acute PVR (24/107 [22%] vs 67/99 [11%] p=0.04) compared to patients <172cm. A subsequent cohort of 56 patients >172cm were treated with augmented AI targets of 550 on anterior and 350 on posterior surfaces. When compared to patients >172cm treated with standard AI targets, FPI increased (37/56 [65%] vs 50/107 [47%] p=0.02) and acute PVR decreased (1/56 [2%] vs 24/107 [22%] p<0.01). There was no difference in total procedure time (01:23:31 ± 00:20:07 vs 01:23:39 ± 00:20:05 p=0.98) or FPI time (01:05:10 ± 00:17:52 vs 01:03:01 ± 00:17:10 p=0.51) between groups.

Conclusions: Height is associated with a lack of FPI and increased acute PVR. Using AI guided radiofrequency ablation, height-based adjustment of AI targets increase acute FPI and reduce acute PVR without affecting procedure times. Personalized AF ablation strategies optimize acute ablation outcomes.