Omnipolarity applied to equi-spaced electrode array for ventricular tachycardia substrate mapping

Abstract

Aims Bipolar electrogram (Bi EGM )-based substrate maps are heavily influenced by direction of a wavefront to the mapping bipole. In this study, we evaluate high-resolution, orientation-independent peak-to-peak voltage (Vpp) maps obtained with an equi-spaced electrode array and omnipolar EGMs (OT EGMs ), measure its beat-to-beat consistency, and assess its ability to delineate diseased areas within the myocardium compared against traditional Bi EGMs on two orientations: along (AL) and across (AC) array splines. Methods and results The endocardium of the left ventricle of 10 pigs (three healthy and seven infarcted) were each mapped using an Advisor™ HD grid with a research EnSite Precision™ system. Cardiac magnetic resonance images with late gadolinium enhancement were registered with electroanatomical maps and were used for gross scar delineation. Over healthy areas, OT EGM Vpp values are larger than AL bipoles by 27% and AC bipoles by 26%, and over infarcted areas OT EGM Vpp values are 23% larger than AL bipoles and 27% larger than AC bipoles ( P < 0.05). Omnipolar EGM voltage maps were 37% denser than Bi EGM maps. In addition, OT EGM Vpp values are more consistent than bipolar Vpps showing less beat-by-beat variation than Bi EGM by 39% and 47% over both infarcted and healthy areas, respectively ( P < 0.01). Omnipolar EGM better delineate infarcted areas than traditional Bi EGMs from both orientations. Conclusion An equi-spaced electrode grid when combined with omnipolar methodology yielded the largest detectable bipolar-like voltage and is void of directional influences, providing reliable voltage assessment within infarcted and non-infarcted regions of the heart.

Catheter ablation of ventricular arrhythmia guided by a high‐density grid catheter

“…Electrodes on an adjacent spline are equally spaced (Figure 1A). 9 Irrigation ports are located at the junction of the distal main catheter body and the HDG splines and irrigated via a pressure bag with heparinized saline at a minimum of 2 mL/min. Bipolar EGMs can be created in a linear or across spline configuration to enable bipolar EGM creation at orthogonal orientations.…”

Updates in Ventricular Tachycardia Ablation

“…An omnipole was described as resolving a signal from all possible simultaneous bipoles (from every direction around the mapping location) from the electric field generated by a travelling wave for the definitive assessment of local cardiac wavefront properties, such as speed and direction. 57) 58) An omnipolar voltage was further described for the definition of ventricular and atrial substrate, defining voltages along the maximal bipolar direction of propagation, 59) 60) 61) using a similar methodology. Omnipolar voltages in a porcine infarct model were shown to be larger than traditional bipoles, more consistent when in the infarcted area, and overall substrate maps better correlated with scar defined by cMR.…”

Reinserting Physiology into Cardiac Mapping Using Omnipolar Electrograms

“…Omnipolar EGMs, together with regularly spaced grid catheters, aim to provide physiologically relevant measurements of the substrate and rapidly provide high-density maps. Recent works by Porta-Sanchez and coworkers 34,35 and Magtibay and coworkers 36,37 demonstrated the use of omnipolar EGMs in ex vivo and in vivo mapping of ventricles. Both studies reinforced the concept of catheter-orientation dependence of bipolar measurements especially for voltage/substrate mapping.…”

“…Porta-Sanchez and coworkers' 34,35 in vivo work applied grid-like catheters and omnipolar EGMs to a preclinical environment in more realistic scenarios where factors, such as tissue contact and movement, could be detrimental. In this study, pigs with ventricular myocardial infarctions were mapped.…”