Clinical Study Of AI-guided Wide Antral Catheter Ablation For Paroxysmal Atrial Fibrillation

Objectives: Ablation Index(AI),a novel non,includes contact force,time,and power of radiofrequency application.Compared to Force-Time integral(FTI)— linear lesion quality marker including contact force and time,AI more truly reflect the Ablation lesion depth according to the animal experiment.However,atrial wall thickness variation within the wide antral catheter ablation(WACA)circle is quite significant in that left atrium internal anatomy.The purpose of this study was to use CASE(CT merge,C;Antrum ablation,A;Scientific evaluation,SE)strategy conducting AI-guided catheter ablation for Paroxysmal atrial fibrillation(PAF);the left atrial myocardial thickness was measured at different segments of the ablation circles by the multi detector CT(MDCT)scanning of the left atrium.We examined the safety and clinical efficacy of WACA ablation(WACA)for paroxysmal atrial fibrillation under the guidance of AI,as well as the relationship between GAP formation,AI value and myocardial thickness were discussed.Methods: We evaluated 102 consecutive patients(mean age,65 ± 9 years;56% men)with PAF who underwent AI-guided CASE strategy for ipsilateral pulmonary vein isolation(PVI)in Shanghai general people's hospital from 2017-10 to 2018-04.All patients underwent MDCT scanning and 3-D reconstruction of left atrium and pulmonary vein before the procedure.The left atrial model was constructed by point-by-point mode under the CARTO3 system,and then merged with the MDCT3-D model.Point by point ablation was adopted in the power mode until bilateral pulmonary vein isolation(PVI).Each WACA circle was subdivided into 8 segments,and overall 7143 radiofrequency applications were delivered,including 125 gaps in PVI ablation lines.For each radiofrequency tag within the ablation circle,we collected data on ablation lesion depth(time of application,delivery power,impedance drop,average contact force,force-time integral [FTI],and AI)and left atrial wall thickness measured by multi detector computer tomography(MDCT)scanning.All ablation points were divided into two groups: the gap group and the non-gap group.During the perioperative period of each patient,anticoagulation was standardized and informed consent was signed,followed up with 24-hour dynamic electrocardiogram at 1,3,6,12 months after the procedure,respectively.Results: WACA for PVI were performed in All patients.Steam POP occurred in 3cases,and serious complications such as cardiac tamponade,embolism and massive hemorrhage have no found during ablation.Inguinal hematoma occurred in 2 cases after the procedure.Among 102 patients,PVI was performed in 67 cases without gaps and 35 cases with gaps within LPV circles,while PVI was performed in60 cases without gaps and 42 cases with gaps within RPV circles.The anterior wall and the roof were the thickest segments within WACA circle,in which 85.8% of gaps concentrated,while the posterior wall and the inferior wall are the thinnest,in which no gap or few gap.Gap formation was significantly associated with FTI,AI,wall thickness,FTI/wall thickness and AI/wall thickness.AI/wall thickness had the highest predictive value for gap formation,with a cutoff of 195.6 au/mm appearing suitable for effective ablation.After 12 months of follow-up,8 patients had recurrence(3 cases of atrial tachycardia,2 cases of atrial flutter,3 cases of atrial fibrillation),and 4 patients lost follow-up.The success rate was 90.0% at 12 months after procedure.Conclusions AI-guided catheter ablation for paroxysmal atrial fibrillation under CASE strategy was safe,feasible,effective and has a high success rate,and the success rate of 1-year follow-up is 90.0%.The thickness of the atrial wall was significantly of variation in different regions,with anterior wall was the thickest segment and posterior and inferior walls were the thinnest,in which the ablation circle was measured by MDCT.The distribution of GAP formation was associated with the myocardial thickness of the ablation circle.Compared to the ablation point in the gap group and non-gap group,AI,FTI,FTI/Thickness and AI/Thickness had a significant difference.AI/wall thickness by normalizing myocardial thickness variation along the WACA circle was a strong predictor of gap formation,with a target of 195.6 au/mm appearing suitable for effective ablation.