Background: Major complications during AF ablation procedure are rare, nonetheless special attention is required when some potentially risky areas (such as posterior locations) are ablated. Recently, a novel technology able to measure local tissue impedance (LI) aimed at validating confidently ablation endpoints has become available for clinical use. Purpose: This analysis explores the relationship between LI parameters, ablation spot locations and procedural success during ablation of pulmonary veins (PVs) in AF patients. Methods: A novel ablation catheter (Intellanav MiFi OI catheter, Boston Scientific) with dedicated algorithm (DirectSense - DS -) was used to measure LI at the distal electrode of this catheter. Each targeted spot was characterized in terms of RF delivery time, LI and its variations during ablation procedure according to different ablation sites around the PVs. 7 sites around the left (LPV) and right (RPV) pair of PV for LI evaluation during ablation were defined: 2 for posterior sites (PS) (posterior inferior and posterior superior) and 5 for other PV locations (OS) (anterior superior, anterior inferior, inferior, carina, and superior). Ablation endpoint was PVI. Results: A total of 950 ablation spots performed around PVs from 20 consecutive pts were analyzed: 686 (72%) at OS (48.3% at RPVs and 51.7% at LPVs) and 264 (28%) at PS (53.8% at RPVs and 46.2% at LPVs). The mean LI was 106±14Ω prior to ablation and 92.5±11Ω after ablation (mean LI drop of 13.5±8Ω) during a median RF time of 26 [19 – 34] sec for each ablation spot. No differences were found in terms of starting LI or ending LI between PS and OS (105.8±14Ω at PS vs 106±14Ω at OS for starting LI, p=0.7979; 93±11Ω at PS vs 92.3±11Ω at OS for ending LI; p=0.2374) whereas the median RF delivery time was significantly shorter in PS spots group (23 [18-31] sec at PS vs 27 [19-36] sec at OS, p=0.0001). No differences were found between groups in terms of RF delivery with an absolute impedance drop greater than 20Ω or an impedance drop variation greater than 15% (22% vs 23.8% of the cases by more than 20Ω of absolute impedance drop, p=0.6173; 33% vs 32.4% of the cases characterized by more than 15% impedance drop, p=0.9233). No steam pops or complications during the procedures were reported. The acute procedural success was 100%, with all PVs successfully isolated in all study patients. Conclusions: In our preliminary experience, an ablation strategy for PVI guided by DS technology seems to be safe and effective. Measured LI before and after RF delivery and LI drop appear to be consistent and homogeneous across different peri-venous ablation locations, even in high risk PV areas as posterior ones.
A novel local impedance algorithm to guide effective pulmonary vein isolation in AF patients: preliminary experience across different ablation sites
L. Segreti;MG. Bongiorni;V. La Rocca;G. Zucchelli;F. Casati;
2019-01-01
Abstract
Background: Major complications during AF ablation procedure are rare, nonetheless special attention is required when some potentially risky areas (such as posterior locations) are ablated. Recently, a novel technology able to measure local tissue impedance (LI) aimed at validating confidently ablation endpoints has become available for clinical use. Purpose: This analysis explores the relationship between LI parameters, ablation spot locations and procedural success during ablation of pulmonary veins (PVs) in AF patients. Methods: A novel ablation catheter (Intellanav MiFi OI catheter, Boston Scientific) with dedicated algorithm (DirectSense - DS -) was used to measure LI at the distal electrode of this catheter. Each targeted spot was characterized in terms of RF delivery time, LI and its variations during ablation procedure according to different ablation sites around the PVs. 7 sites around the left (LPV) and right (RPV) pair of PV for LI evaluation during ablation were defined: 2 for posterior sites (PS) (posterior inferior and posterior superior) and 5 for other PV locations (OS) (anterior superior, anterior inferior, inferior, carina, and superior). Ablation endpoint was PVI. Results: A total of 950 ablation spots performed around PVs from 20 consecutive pts were analyzed: 686 (72%) at OS (48.3% at RPVs and 51.7% at LPVs) and 264 (28%) at PS (53.8% at RPVs and 46.2% at LPVs). The mean LI was 106±14Ω prior to ablation and 92.5±11Ω after ablation (mean LI drop of 13.5±8Ω) during a median RF time of 26 [19 – 34] sec for each ablation spot. No differences were found in terms of starting LI or ending LI between PS and OS (105.8±14Ω at PS vs 106±14Ω at OS for starting LI, p=0.7979; 93±11Ω at PS vs 92.3±11Ω at OS for ending LI; p=0.2374) whereas the median RF delivery time was significantly shorter in PS spots group (23 [18-31] sec at PS vs 27 [19-36] sec at OS, p=0.0001). No differences were found between groups in terms of RF delivery with an absolute impedance drop greater than 20Ω or an impedance drop variation greater than 15% (22% vs 23.8% of the cases by more than 20Ω of absolute impedance drop, p=0.6173; 33% vs 32.4% of the cases characterized by more than 15% impedance drop, p=0.9233). No steam pops or complications during the procedures were reported. The acute procedural success was 100%, with all PVs successfully isolated in all study patients. Conclusions: In our preliminary experience, an ablation strategy for PVI guided by DS technology seems to be safe and effective. Measured LI before and after RF delivery and LI drop appear to be consistent and homogeneous across different peri-venous ablation locations, even in high risk PV areas as posterior ones.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
