Optical mapping of arrhythmogenic remodeling in the failing human heart

This chapter provides a brief overview of functional and molecular remodeling in failing human hearts, procured from patients receiving a transplant, and compared to donor hearts, which were procured for transplantation but found unsuitable for transplant. It shows human-specific mechanisms of arrhythmogenic remodeling related to slowing of conduction velocity and repolarization, change in excitation-contraction coupling, and significant remodeling of different isoforms of beta-adrenergic receptors, specifically differential remodeling of β₁versus β₂-adrenergic receptors and associated signaling. The prolongation of action potential duration and QT interval is a common feature across experimental heart failure models and in patients with heart failure. Optical mapping studies on human ventricular wedge preparations have recently helped to shed significant light on the specifics of repolarization remodeling in human heart failure, contrasting them with those observed from animal model experiments.