Basic/Translational Science -> Intact Heart Electrophysiology (includes Pharmacology and Optical Mapping) D-PO04 - Poster Session IV (ID 15) Poster

D-PO04-048 - Atrial Repolarization Synchronizes Over Long Distances During Pacing But Behaves As A Propagating Wave During Atrial Fibrillation (ID 384)

 V. Sobota: Nothing relevant to disclose.


Background: Electrotonic interactions during atrial repolarization has not been studied extensively.
Objective: To investigate the interaction of activation and repolarization patterns in the left atrium (LA) during pacing and atrial fibrillation (AF).
Methods: Optical mapping was performed in perfused goat hearts (n=6) that underwent 3 weeks of pacing-induced AF. Optical action potentials (100x100) were acquired in a 2x2cm area of the LA free wall during pacing (CL=350ms, 7±5 pacing sites) and AF. Activation time (AT, maximum upstroke derivative) and repolarization time (RT, time at 80% repolarization) were determined for each pixel. To assess the correlation between activation and repolarization patterns, we calculated the Pearson’s r between AT and RT. To evaluate the changes in dispersion of APD80 during pacing, we calculated the prolongation of APD80 (ΔAPD80) for each pixel as a difference between average APD80 during pacing and the APD80 obtained during pacing at a particular site.
Results: Prolongation of APD80 at the site of pacing was observed (ΔAPD80 8±5ms, i.e. 6.6±4.2%), leading to a synchronous repolarization pattern with a weak correlation to the activation pattern (r=0.22±0.24 and r=0.38±0.38, pacing within and outside the field of view, respectively). However, a propagating behavior of the repolarization wave was observed during AF, showing a stronger correlation between AT and RT (r=0.65±0.05).
Conclusion: During pacing, the APD at the site of pacing prolongs, leading to a synchronous repolarization throughout the field of view. By contrast, the repolarization during AF shows a wave-like propagating behavior, with pattern similar to the preceding activation.