Many diseases of the heart muscle (cardiomyopathies) are directly tied to malfunction of heart muscle cells (cardiomyocytes, CMs). Cardiomyocyte morphology, particularly the length-to-width ratio, is used as a metric of cardiac pathology and remodeling. We are building devices to evaluate how CMs respond to mechanical stimuli such as cell shape and substrate stiffness. These mechanical stimuli cause changes in the intracellular structure of CMs and thus alter their ability to generate contractile forces. We selectively micropattern extracellular matrix proteins on hydrogel platforms to restrict cell size and arrangement while monitoring cellular morphology and traction forces using fiducial markers within the gels.