In Vivo Analysis of Conduction Pattern Dynamics: System Development and Application Using OpenEP

Atrial low voltage, measured during electroanatomic mapping, may indicate the presence of atrial fibrosis, has been implicated in atrial fibrillation perpetuation andshows useful associations with clinical outcomes.Low voltage is however a marker of the underlying substrate, but it is the electrophysiological properties of this substrate which are critical to arrhythmogenesis.Nevertheless, the influence of low voltage on in vivo conduction pattern dynamics is uncertain.Here, we develop a novel method for dynamic conduction velocity assessment.A central electrode pair of a multi-spline, multi-electrode catheter was used to apply a series of pacing trains (S1) followed by coupled premature extra stimulus (S2).For each S1S2 interval, two perpendicular electrodes were selected to calculate conduction velocities in longitudinal and transverse directions.Conduction velocity restitution curves were generated by plotting conduction velocity at each S1S2 interval.The slope of the line fitted to the descending part of the conduction velocity restitution curve showed a very good correlation with the percentage of low voltage area underlying the geodesic path connecting electrodes on which conduction velocity was calculated.(R 2 = 0.64).Using this novel method, we could achieve intraprocedural assessment of the effect of low voltage regions on conduction pattern dynamics.