Introduction: Despite technological advances of the electroanatomic system, correct identification of the type of mechanism and its location is the current challenge for electrophysiologists. Several aspects including mapping technology, complexity of the arrhythmia, signal processing map pipeline, farfield and spatial resolution could affect identification of the true electrophysiology substrate mechanism. This study aimed to investigate the role of electrical mapping and different signal processing pipelines in charactering cardiac rhythms including atrial fibrillation and compare them with the observed in high-resolution optical mapping.
Methods: Experiments consisted of Langendorff-perfused rabbit hearts undergoing cardiac arrhythmias, induced through electrical pacing, associated with APD shortening, through administration of drugs. Epicardium electrical activity is recorded by multielectrode arrays placed on the heart while it is inside a torso-tank setup. Epicardial activity is also simultaneously recorded by high-density panoramic optical mapping. Electrical and optical signals are processed with different signal processing pipelines to allow rhythm characterization.
Results: Atrial and ventricular arrhythmias including tachycardias and fibrillations were induced and mapped through frequency, isopotential, phase and isochrone maps, showing foci and reentrant activities that are spatiotemporal stable or not, according to the underlying mechanism. Optical mapping, although it is considered the gold standard, customized signal processing pipeline, including farfield removal in atrial optical action potentials are highly required to avoid misleading atria mechanism, not necessary for ventricular arrhythmias. Also, a pipeline was applied to epicardial electrical signals, and reconstructed electrograms, obtained from ECGi, to be able show the mapped mechanisms seen in optical mapping. Electrical mapping usually fails to represent the detailed underlying mechanisms due to its limited covered area.
Conclusion: Developing research that aims to improve the current signal processing techniques for mapping systems is crucial in deepening the detection and understanding of arrhythmogenic mechanisms, particularly when paired with advanced high resolution imaging techniques like panoramic optical mapping.