Omnipolar mapping
Omnipolar mapping has been reported to overcome technical limitations associated with conventional bipolar electrograms, obviating issues with electrode orientation and activation timing (141). Omnipolar electrograms leverage data from unipolar and bipolar electrograms applied to a mathematical model of a propagating wavefront to produce ‘virtual’ bipolar electrograms. By interrogating electrograms through 360o, omnipolar mapping can extract maximal voltage independent of catheter orientation as well as providing measures activation direction. Validation studies using in silico modelling, multi-electrode array recordings of cardiomyocyte monolayers, and optical mapping of uniform and re-entrant waves have demonstrated good correlation between omnipolar parameters and conventional electrophysiological techniques (142).
Whole heart studies have provided further evidence of the utility of omnipolar technology. In Langendorff-perfused rabbit and porcine hearts, omnipolar voltages measured from the interventricular septum were significantly higher than those obtained with horizontally or vertically orientated bipolar electrodes (143). Voltages in ex-vivo human hearts were similarly increased. They highlighted the potential need for adjusting thresholds for defining scar given more tissue would be characterized as healthy if current standards are used. Haldar et al. compared atrial bipolar and omnipolar voltages in canine hearts, and reported higher voltages with the latter when assessed in sinus rhythm or AF (144). Notably, omnipolar voltages demonstrated remarkable beat-to-beat consistency across rhythms in both studies, potentially reducing the influence of rhythms with variable activation patterns such as AF. Rillo et al. reported higher atrial voltages and smaller burden of LVAs in patients undergoing AF ablation when mapped in sinus rhythm (145).