title: Left atrial isthmus line ablation using a remote robotic navigation system: feasibility, efficacy and long-term outcome.
abstract: BACKGROUND
  Left atrial isthmus (LAI)-ablation in addition to circumferential pulmonary vein isolation (CPVI) may improve outcomes in select patients with atrial fibrillation (AF). However, bidirectional LAI-block is difficult to obtain. No systematic evaluation reporting on the feasibility and efficacy of LAI-ablation using a robotic navigation system (RNS) exists.
  
  
  RESULTS
  In this pilot study, CPVI combined with LAI-ablation were performed using a RNS and 3D-mapping system in 42 patients with persistent (n = 24, 57.1 %) or longstanding persistent AF. Ablation was performed using either a 3.5 mm irrigated tip catheter (ITC) with 6 (group-A, n = 16; max. 40 W, contact force 10-40 g) or (after a steam pop occurred in one patient) with a 4 mm ITC with 12 irrigation holes (group-B, n = 26; max. 30 W, contact force 10-30 g). Epicardial ablation was performed manually whenever bidirectional LAI-block could not be obtained with a maximum of 20 endocardial RF-applications. LAI-conduction block was achieved in all patients using RNS; in six patients (14.3 %), additional epicardial ablation was required to achieve LAI-block. A steam pop occurred during LAI-ablation resulting in cardiac tamponade in one patient in group-A. After a median follow-up period of 21 months, arrhythmia recurrence was seen in in 23/42 patients (18 patients with AF and 5 patients with atrial tachycardia) and repeat procedure was performed in 12 (28.6 %) patients; recovered LAI-conduction was found in 5/12 (41.7 %) patients. The RNS-group was compared to a historical group of 20 patients with manual LAI-ablation. Using RNS, LAI-block was more often achieved (42 (100 %) vs 16 (80 %), p < 0.01) and epicardial ablation was required in a significantly smaller number of patients (6 (14.3) vs 10 (50 %), p < 0.01).
  
  
  CONCLUSIONS
  LAI-ablation using RNS appears to be feasible in all patients. At repeat procedure, LAI-conduction can frequently occur; power and contact-force adaption appears to be mandatory to reduce the risk of complications. Using RNS, instead of a manual approach for LAI-line ablation may facilitate creation of a bidirectional LAI-block.
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany, arillig5@yahoo.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Rillig
authors.forename: Boris
authors.initials: B
authors.lastname: Schmidt
authors.forename: Britta
authors.initials: B
authors.lastname: Feige
authors.forename: Erik
authors.initials: E
authors.lastname: Wissner
authors.forename: Andreas
authors.initials: A
authors.lastname: Metzner
authors.forename: Anita
authors.initials: A
authors.lastname: Arya
authors.forename: Shibu
authors.initials: S
authors.lastname: Mathew
authors.forename: Hisaki
authors.initials: H
authors.lastname: Makimoto
authors.forename: Peter
authors.initials: P
authors.lastname: Wohlmuth
authors.forename: Feifan
authors.initials: F
authors.lastname: Ouyang
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Kuck
authors.forename: Roland Richard
authors.initials: RR
authors.lastname: Tilz
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D005240:Feasibility Studies; D005500:Follow-Up Studies; D006325:Heart Atria / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D011667:Pulmonary Veins / Q000601:surgery; D012008:Recurrence; D012086:Reoperation; D012371:Robotics; D013997:Time Factors; D016896:Treatment Outcome
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