Catheter Ablation -> Atrial Fibrillation & Atrial Flutter: -> Clinical Trials / Outcomes D-AB23 - AF Management: Questioning Current Approaches & Improving Outcomes (ID 35) Abstract Plus

D-AB23-05 - Predicting Ablation Lesion Quality During Pulmonary Vein Isolation: Is Ablation Index Reliable? (ID 797)


Background: Ablation Index (AI) incorporates power, time and contact force and is reported to be a marker of lesion quality. AI guided AF ablation has been shown to reduce PV reconnection.
Objective: To study PV reconnection predictability of AI and impedance drop.
Methods: In AF recurrence pts, we retrospectively compared AI and impedance drop during the index PVI procedure in 35 consecutive pts (case) with PV reconnections to 16 pts without PV reconnection (control). Right and left PVs were divided into 2 segments each (roof/anterior and posterior/inferior).
Results: Mean age was 62±10 y in case group (vs 65±6 y) with 23 (65.7%) males (vs 62.5%). Of 47 PV reconnected areas, 18 (38.3%) were in the right anterior/roof segment, 15 (31.9%) right posterior/inferior, 7 (14.9%) left roof/anterior and left posterior/inferior segments. Mean AI was 452.2±95 (vs 524±86) and mean impedance drop 7.9±3.2 Ohms (vs 12±4) in the PV re-connection group. Segmented mean AI was significantly lower in all but right posterior/inferior segment, whereas impedance drop was significantly lower in all segments with reconnection. Impedance drop >7 Ohms was an excellent predictor of durable PVI (OR 12.8, 95% CI 5.1-31.8, p <0.0001). Conversely, neither AI > 550 in anterior/roof segment (OR 0.14, 95% CI 0.05-0.5) or AI > 400 in posterior/inferior segment (OR 0.38, 95% CI 0.1-1.1) were predictive of durable PVI.
Conclusion: Impedance drop > 7 Ohms is a better predictor of lesion quality than ablation index. Indeed, a high ablation index can occur despite low impedance drop and tissue contact if balanced by power/time. Future algorithms should incorporate tissue feedback (like impedance changes) to better predict lesion quality.