Po-03-119 atrial substrate can be assessed during pacing instead of sinus rhythm? – advantage and limitation of sinus-node pacing map-

Atrial pacing (AP) is frequently used instead of sinus rhythm (SR) during substrate mapping to save time with stable pacing rhythm. However, the effect of pacing on atrial substrates such as activation, voltages and frequency of electrograms has not been systematically examined. We aimed to elucidate the advantage and limitation of AP-map. In patients who underwent catheter ablation for atrial fibrillation, atrial substrate maps of left atrium were created after the ablation during SR, AP with the cycle length of 300ms (AP300) and AP with the cycle length of 600ms (AP600) with a HD grid catheter using the Ensite X mapping system. AP was performed from high right atrium around sinus node with a spot catheter. Mapping time, the number of acquired electrograms points, mean omnipolar voltage of electrograms, and mean peak frequency of electrograms were compared among created maps. The pattern of activation in left atrium was also analyzed in each map. A total of 60 left atrium maps were created in 20 patients. The summary of the results is shown in the figure. The figure also exhibits voltage maps and peak frequency maps during SR, AP600, and AP300 of a representative case. When compared with during SR, mapping time was significantly reduced and mean voltage and mean peak frequency of electrograms significantly decreased during AP600. Moreover, mapping time was much shorter and mean peak-frequency of electrograms was much lower during AP300. The number of acquired electrogram points was significantly higher during AP300 compared with SR. Mean voltage of electrograms became significantly lower during AP300 compared with SR. Left atrial activation pattern during SR and that during AP were almost the same (Each wave front collided around the 4 o’clock or 5 o’clock of mitral annulus in all maps). Although AP-map allowed us to acquire higher-resolution maps in shorter time without changing activation pattern, amplitude and frequency of electrograms may be reduced as the cycle length of AP becomes shorter.