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).