PO-04-230 IMPROVED VISUALIZATION OF LOW AMPLITUDE LATE POTENTIALS WITH VT SUBSTRATE MAPPING USING A NOVEL EP RECORDING SYSTEM

Abstract

Accurate identification of low-voltage electrograms (EGMs) suffer from artifacts that often interfere with physiological signals in the <0.1-0.5mV range. For substrate based ablation of ventricular tachycardia (VT), dense scar is defined as regions of myocardium with EGM amplitudes below 0.5 mV. Within these regions, current EP recording systems can fail at identifying low-voltage late potentials that are effective targets of ablation therapy. More recently, new EP amplifiers designed specifically to reduce the impact of interference on the fidelity of signals have been introduced. This study used a novel EP recording system (ECGenius System, CathVision, Copenhagen, DK) to identify low amplitude (<0.5mV) late potentials in regions of scar, and quantify their characteristics in a head-head comparison to a standard recording system (LabSystem Pro, Boston Scientific, MA). We collected recordings in parallel from four patients (30-250 Hz bipolar recording bandwidth) referred to our center for an EP study and ablation for VT. We performed substrate mapping during sinus rhythm with a standard 4mm irrigated ablation catheter (SmartTouch, Biosense Webster, Diamond Bar, CA) and a multi-spline mapping catheter (PentaRay, Biosense Webster). In regions of dense scar (< 0.5 mV, delineated with 3-D electroanatomical mapping) we identified late potentials that were above the baseline noise level of the CathVision system that were otherwise not clearly visible with the LabSystem Pro system. In four patients we identified fourteen sites with late potentials (110 beats) that were only identified with the CathVision System (see figure). The average amplitude of the late signals was 0.079 +/- 0.063 mV, which was above the baseline mean noise of 0.008 mV (range 0.006 to 0.015 mV). In contrast, the baseline mean noise of the LabSystem Pro was 0.060 mV (range 0.040 to 0.090 mV). The mean delay of the late potentials (after the start of the surface ECG QRS) was 377ms (range 198 to 470ms). Improved visualization of low voltage EGMs and late potentials can improve upon substrate-based ablation of ischemic VT. With a novel, and state-of-the art recording amplifier, we demonstrate an improved ability to detect clinically relevant sites for ablation that were not visible with a standard recording system. This technology could improve upon current ablation strategies, and may be particularly useful in the current era of micro-electrodes and relatively smaller recording voltages.