Image Story: Pathways Using an Orientation-Independent Catheter
Ruben Casado Arroyo, Sofia Chatzikyriakou
A 53 year-old woman was admitted to the emergency unit due to a short QRS tachycardia at 180 bpm. The electrophysiological study showed an orthodromic left lateral accessory pathway.
Video 1 The pathway was mapped using the Advisor HD grid Catheter Mapping, Sensor Enabled™ (Abbot, St. Paul, MN, USA). The detailed map of the accessory pathway is described below.
Using the Omnipolar Technology (1-3), we were able to identify the trajectory of the accessory pathway. The catheter was located along the mitral annulus, with the distal pole (D1) closer to the ventricular side and the proximal (D4) closer to the atrial side. The best unipolar activation, sharp QS deflection, corresponds to HD1 that is shown in panel 1. Based on this information and this localization of the catheter, the best bipolar activation is presented in panel 2. We show different catheter bipolar activation in relation to the best unipolar (D1). The first bipolar presented D1-D2, shows a fusion of ventricular and atrial electrogram. The other bipolar activation presented, vertical bipole, D1-C1 and oblique bipole, D1-C2, show a clear differentiation of and atrial and ventricular signal. Both atrial and ventricular electrograms are clearly separated by a distance. The activation of the accessory pathway continues to D2-D3 that shows a fusion of ventricular and atrial activity being the ventricular amplitude bigger than the atrial. Lastly, D3-D4 bipole shows the reverse, the amplitude of the ventricular activity is smaller than the atrial and an accessory pathway potential can be identified (AccP). The ablation catheter was positioned in D3-D4 and a single application was enough to eliminate the accessory pathway. This technology derives the direction of wave front activation from a single point and is independent of catheter orientation (video 1).
This case demonstrates the utility of the fixed-spacing grid array catheters. This tool provides reproducible myocardial activation (directionality) in the context of an accessory pathway. Omnipolar voltages analysis provide physiologically substrate characterization and facilitates the characterization of this kind of substrates. This new technology helps to identify the direction of the wave front activation from a single point (accessory pathway connection) and is independent of catheter orientation. The use of this catheter will improve the results of ablation of the accessory pathway.
This is the first case of ablation of an accessory pathway using this new technology that is free of catheter orientation effects and identifies the direction of the pathway between the atrium and the ventricle.