Simultaneous Recording of Electrical and Panoramic Optical Mapping from In-vivo Isolated Rabbit Hearts: From Sinus Rhythm to Induced Arrhythmia

Jimena Siles Paredes1, Ilija Uzelac2, Vinicius Silva3, Italo Sandoval Ramos de Oliveira4, Giovanni Weber3, Joao Salinet5
1Graduate Program in Biotechnoscience, Federal University of ABC, 2Georgia Institute of Technology, 3Federal University of ABC, 4Universidade Federal do ABC, 5HEartLab, Federal University of ABC


Abstract

Introduction: The accurate identification of the type and location of arrhythmia mechanisms remains a significant challenge for electrophysiologists, and commercial systems may influence the process. This study presents the initial results of a novel in vivo model for customizing electrophysiology metrics and maps. Methods: New Zealand isolated rabbit hearts were Langendorff retro-gradely perfused (Tyrode solution, 38°C, pH 7.4 and 15 ml/min, (-)-Blebbistatin 1.71 µM). We acquired epicardial electrical activity simultaneously during sinus rhythm, pacing, and induced atrial arrhythmia using panoramic optical mapping (dye: Di-4-ANBDQPQ; excitation: high-power deep-red LEDs, aspheric condenser lens, and band-pass filters 650/40 nm; emission: long pass filters 715 nm, and CMOS cameras with 1000x1264 pixels, 500 fps). We also used epicardium contact electrical mapping (two in-house build MEAs of PET with 16 silver electrodes each, 64-channel amplifier, Fs: 4 kHz). An in-house 3D heart reconstruction system (driver DRV8825, JK35HS34-1004, Labview GUI), allows obtaining 3D silhouettes from 2D heart images taken every 5° until a 360° full rotation (i.e 72 images). The signals were pre-processed and post-processed offline, and the electrical and optical local activation time (LAT) was compared between them in regular and irregular rhythm protocols.
Results: 7 out of 10 experiments were performed (3.80±0,17 Kg). 3D reconstruction of atria allowed building optical vs. electrical potential and local activation times (LATs) maps (DF and phase being performed). Far-field electrical mapping causes divergences in the temporal evolution of local activation times (LATs) during sinus rhythm (-3.1 ± 10.9 ms), pacing (-6.7 ± 1.4 ms), and arrhythmia (-1.9 ± 4.1 ms). Conclusion: This study proposes a highly complex animal model and presents a preliminary analysis. In the near future, it will be possible to customize electrophysiology metrics and maps from electrical mapping based on those obtained simultaneously by optical mapping, using a signal and image processing pipeline.