BS-400-21 MULTIPOLAR ELECTROGRAMS: A NOVEL ALGORITHM FOR ACCURATE ANNOTATION OF NEAR-FIELD POTENTIALS IN SCAR

Abstract

Electrogram annotation in scar is challenging due to the presence of multicomponent potentials containing near and far field activities. While bipolar electrograms eliminate the mutual far field component enclosed between two closely spaced electrodes, a large far field component often remains. This may result in inconsistent voltage and time measurements. Multielectrode catheters provides an opportunity to improve far-field rejection by reducing the common components across multiple unipolar electrograms. To determine the effect of multiple unipolar signals decomposition method in the ability to reduce the far field component from the unipolar signal. In 6 swine with chronic infarction, the left ventricle was mapped using Carto 3® and multielectrode array catheter (OptrellTM, Biosense Webster). A novel algorithm utilizing Principal Component Analysis was used to estimate the common components of each unipolar signal with its neighboring electrodes, weighted with inverse proportion to their distance. The mutual component was subtracted from each unipolar signal for creating a multipolar electrogram as in Figure 1. The utility of multipolar electrograms in removing far-field activity from complex signals was compared with traditional bipolar electrograms and reported as median voltage amplitude with 25-75 interquartile range. In infarct border zones with complex multicomponent signals (n=76), multipolar electrograms produced a significantly lower far field signal amplitude in comparison to standard bipolar electrograms (0.45mV [IQR 0.3-0.9] vs 1.8mV [1.1-2.4], respectively P<0.001). Figure 1 shows an example of a complex multipotential signal recorded at infarct border zone as it represented by unipolar, bipolar and multipolar electrograms. Multipolar electrograms produced higher amplitude near field signals (2.9mV [IQR 2.2-3.6] vs 1.0 [0.6-1.8mV], respectively P<0.01) as shown in Figure 2. Multipolar electrograms produced by reduction of common components across multiple unipolar electrograms reduce far field potentials significantly greater than bipolar electrograms. This novel method may be particularly helpful for mapping complex substrates including scar.View Large Image Figure ViewerDownload Hi-res image Download (PPT)