Variations in the anatomy at the pulmonary venous- left atrial junction are not unusual and may hinder attempts to isolate the veins during catheter ablation for atrial fibrillation (AF). Computed tomography (CT) or magnetic resonance imaging (MRI) confirmation of pulmonary vein (PV) anatomy with or without three-dimensional image integration (3D-II) into mapping systems, will highlight anatomical variations and may aid catheter ablation. However, evidence regarding the impact of 3D-II on outcomes remains contradictory and evidence that variation in anatomy of the veno-atrial junction actually influences outcomes is limited. A new study evaluated the impact of variant PV anatomy and the use of 3D-II on long-term efficacy of catheter ablation for AF.

Consecutive patients who underwent catheter ablation of AF, at St Bartholomew’s Hospital, between 1 April 2002 and 5 October 2007 were included. For all patients in the cohort, wide area circumferential ablation was performed and electrical isolation was confirmed with a multipolar PV mapping catheter. For persistent AF, additional ablation lines (mitral and roof line) were drawn and cavotricuspid isthmus ablation was done in patients with a history of atrial flutter. Conduction block was verified after restoration of sinus rhythm. In addition to PV isolation and linear lesions, starting from 2005 complex fractionated electrograms were also targeted. During the procedure if AF organized into atrial tachycardia (AT), this was mapped and ablated. The patient was cardioverted with a DC shock, if sinus rhythm was not restored following ablation. Patients were discharged the day after the procedure. A 3-month blanking period was observed. Patients with persistent AF/AT or symptomatic paroxysmal AF were offered a repeat procedure. Anticoagulation was continued for a minimum of 3 months and long term anticoagulation was given if the CHADS2 score was ?2.

Success was defined as freedom from symptoms and/or documented AF/AT lasting >30 s following the 3-month blanking period. Single-procedure success was compared for cases performed with and without 3D-II and the impact of 3D-II was also assessed for each mapping system (Carto and NavX). PV anatomy was categorized as follows: (i) normal, (ii) left common trunk, (iii) a right middle vein, and (iv) other variants. The impact of anatomical variations on single-procedure and final outcome was assessed.

Three hundred and fifty patients were studied. 227 (62%) patients underwent catheter ablation with 3D-II. The use of 3D-II was associated with a significantly reduced risk of recurrence [hazard ratio (HR) 0.67; p = 0.020]. Variant PV anatomy was associated with a higher risk of recurrence (HR 1.37; p = 0.044). There was a trend towards improved success with the use of Carto rather than Ensite NavX. Persistent AF was also associated with a higher risk of recurrence (HR 2.00; p < 0.0001). In summary, single-procedure efficacy of PV isolation for AF is improved with use of 3D-II and is reduced with variant PV anatomy.

Reference:

Hunter RJ, Ginks M, Ang R, Diab I, Goromonzi FC, Page S, Baker V, Richmond L, Tayebjee M, Sporton S, Earley MJ, Schilling RJ. Impact of variant pulmonary vein anatomy and image integration on long-term outcome after catheter ablation for atrial fibrillation. Europace. 2010 Dec;12(12):1691-7.