Abstract

The tight interplay between cellular metabolism and the electromechanical function of the heart, known as metabolism–excitation–contraction (MEC) coupling, is fundamental to cardiac physiology and pathology. Dysregulation of this coupling is implicated in various heart diseases. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) offer a valuable, high-throughput model for studying these processes, but advanced, non-invasive techniques are required to simultaneously monitor metabolic state and functional output. This study introduces a novel approach utilizing the registration of NADH photobleaching kinetics to non-invasively assess the metabolic component of MEC coupling in layers of hiPSC-CMs. NADH autofluorescence is a direct indicator of the cellular redox state, and its photobleaching dynamics provide insights into the activity of key metabolic enzymes. We demonstrate that this technique allows for the simultaneous, two-parametric optical mapping of metabolic activity alongside electrical and mechanical parameters. The results reveal a robust correlation between changes in NADH photobleaching rates and alterations in excitation and contraction characteristics, providing a sensitive measure of MEC coupling integrity. This method represents a significant advancement for pharmacological screening and for investigating the mechanisms underlying metabolic heart diseases.