Electromechanical optical mapping.

Optical mapping is a widely used imaging technique for investigating cardiac electrophysiology in intact, Langendorff-perfused hearts. Mechanical contraction of cardiac tissue, however, may result in severe motion artifacts and significant distortion of the fluorescence signals. Therefore, pharmacological uncoupling is widely used to reduce tissue motion. Recently, various image processing algorithms have been proposed to reduce motion artifacts. We will review these technological developments. Furthermore, we will present a novel approach for the three-dimensional, marker-free reconstruction of contracting Langendorff-perfused intact hearts under physiological conditions. The algorithm allows disentangling the fluorescence signals (e.g. membrane voltage or intracellular calcium) from the mechanical motion (e.g. tissue strain). We will discuss the algorithms reconstruction accuracy, resolution, and robustness using experimental data from Langendorff-perfused rabbit hearts.