Ablation index, a novel marker of ablation lesion quality: prediction of pulmonary vein reconnection at repeat electrophysiology study and regional differences in target values

EP Europace, May 2017

Force–Time Integral (FTI) is commonly used as a marker of ablation lesion quality during pulmonary vein isolation (PVI), but does not incorporate power. Ablation Index (AI) is a novel lesion quality marker that utilizes contact force, time, and power in a weighted formula. Furthermore, only a single FTI target value has been suggested despite regional variation in left atrial wall thickness. We aimed to study AI's and FTI's relationships with PV reconnection at repeat electrophysiology study, and regional threshold values that predicted no reconnection.

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Ablation index, a novel marker of ablation lesion quality: prediction of pulmonary vein reconnection at repeat electrophysiology study and regional differences in target values

Europace Ablation index, a novel marker of ablation lesion quality: prediction of pulmonary vein reconnection at repeat electrophysiology study and regional differences in target values Moloy Das 0 1 Jonathan J. Loveday 2 Gareth J. Wynn 0 Sean Gomes 0 Yawer Saeed 0 Laura J. Bonnett 2 Johan E.P. Waktare 0 Derick M. Todd 0 Mark C.S. Hall 0 Richard L. Snowdon 0 Simon Modi 0 Dhiraj Gupta 0 0 Institute of Cardiovascular Medicine and Science, Department of Cardiology, Liverpool Heart and Chest Hospital , Thomas Drive, Liverpool L14 3PE , UK 1 Department of Cardiology, Freeman Hospital , Freeman Road, Newcastle upon Tyne NE7 7DN , UK 2 University of Liverpool , Liverpool L69 3BX , UK Aims Force - Time Integral (FTI) is commonly used as a marker of ablation lesion quality during pulmonary vein isolation (PVI), but does not incorporate power. Ablation Index (AI) is a novel lesion quality marker that utilizes contact force, time, and power in a weighted formula. Furthermore, only a single FTI target value has been suggested despite regional variation in left atrial wall thickness. We aimed to study AI's and FTI's relationships with PV reconnection at repeat electrophysiology study, and regional threshold values that predicted no reconnection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Methods Forty paroxysmal atrial fibrillation patients underwent contact force-guided PVI, and the minimum and mean AI and FTI and results values for each segment were identified according to a 12-segment model. All patients underwent repeat electrophysiology study at 2 months, regardless of symptoms, to identify sites of PV reconnection. Late PV reconnection was seen in 53 (11%) segments in 25 (62%) patients. Reconnected segments had significantly lower minimum AI [308 (252 - 336) vs. 373 (323 - 423), P , 0.0001] and FTI [137 (92 - 182) vs. 228 (157 - 334), P , 0.0001] compared with non-reconnected segments. Minimum AI and FTI were both independently predictive, but AI had a smaller P value. Higher minimum AI and FTI values were required to avoid reconnection in anterior/roof segments than for posterior/inferior segments (P , 0.0001). No reconnection was seen where the minimum AI value was ?370 for posterior/inferior segments and ?480 for anterior/roof segments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion The minimum AI value in a PVI segment is independently predictive of reconnection of that segment at repeat electrophysiology study. Higher AI and FTI values are required for anterior/roof segments than for posterior/inferior segments to prevent reconnection. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Introduction Creation of durable ablation lesions during pulmonary vein isolation (PVI) for atrial fibrillation (AF) is of critical importance to prevent late PV reconnection, which is responsible for the great majority of arrhythmia recurrence in patients with paroxysmal AF.1 Despite improvements in technology, the proportion of PVs remaining chronically isolated following radiofrequency ablation has remained disappointingly low.2,3 This has led to much interest in the delivery of effective ablation lesions. In the absence of real-time assessment of lesion development and transmurality, surrogate measures of lesion quality are commonly utilized. The fall in local impedance during ablation, which has been shown to relate to lesion size,4,5 is commonly used as a marker of the direct effect of ablation on cardiac tissue.6 ? 9 More recently, the minimum Force ? Time Integral (FTI), which multiplies contact What?s new? ? Force ? Time Integral (FTI) is a marker of ablation lesion quality but is limited by the exclusion of power delivery. ? Ablation Index (AI) is a novel marker incorporating contact force, time and power in a weighted formula. ? Only a single FTI target value has previously been identified despite known variation in left atrial wall thickness. ? Minimum AI and FTI were both found to be independently predictive of pulmonary vein isolation segment reconnection at repeat electrophysiology study. ? The relationship with AI was (...truncated)


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Das, Moloy, Loveday, Jonathan J., Wynn, Gareth J., Gomes, Sean, Saeed, Yawer, Bonnett, Laura J., Waktare, Johan E.P., Todd, Derick M., Hall, Mark C.S., Snowdon, Richard L., Modi, Simon, Gupta, Dhiraj. Ablation index, a novel marker of ablation lesion quality: prediction of pulmonary vein reconnection at repeat electrophysiology study and regional differences in target values, EP Europace, 2017, pp. 775-783, Volume 19, Issue 5, DOI: 10.1093/europace/euw105