Randomised Comparison of the Octaray and Pentaray Catheters

Compared with conventional point by point mapping, the use of a multipolar high density Pentaray catheter (Biosense Webster, Diamond Bar, CA, USA) has been found to produce more rapid, accurate maps. This catheter has 20, 2mm2 electrodes. Newer, high density mapping catheters have also been introduced, capable of collecting detailed maps rapidly. Such catheters include the Orion catheter (Boston Scientific, Marlborough, MA, USA) which has 64, 0.4mm2 electrodes and has been shown to be safe and effective in real world usage, and the HD Grid (Abbott Cardiovascular, Lake Forest, IL, USA) which has 16, 1mm electrodes and has been shown to be associated with shorter procedure and fluoroscopy times and better success rates than conventional circular mapping catheters when used for AF ablation.

Of the above high density catheters, the Pentaray is integrated into the Carto3 system. An advantage of this platform for mapping is the ability to use the Tissue Proximity Indicator (TPI) Filter to reduce the number of points collected without contact and improve the accuracy of the subsequent voltage map.

A novel multipolar catheter, iterating on the previous Pentaray catheter is now being introduced: Octaray. This has 48, 0.9mm2 electrodes arranged on 8 splines. In preclinical studies, Octaray has been found to be collect maps faster, at higher density and with greater accuracy for conduction gaps than the Pentaray. The new catheter has been used safely in clinical cases.

Methods This is a randomised, prospective, single centre, interventional study, Thirty patients listed for redo AF ablation procedures on clinical grounds will be included in the study. Procedures will be under conscious sedation or general anaesthetic as per the preference of the operator, as will the mode of transeptal access and sheaths used to deliver the mapping catheter to the left atrium.

At the start of the case, two consecutive LA maps will be taken by the same operator using the Pentaray and Octaray catheters. In both cases, throughout the study the same catheter types will be used. For the Pentaray catheter, this will be the standard 4-4-4 spaced version. The Octaray for the study will be the larger, 20mm spline version, with the 3-3-3-3-3 spacing.