The present disclosure describes methods of differentiating cardiomyocyte progenitor cells and mature cardiomyocyte cells from pluripotent stem cells. The methods may include differentiating pluripotent stems cells on a substrate including (i) laminin-511 or 521 and (ii) laminin-221. The cardiomyocyte progenitor cells and mature cardiomyocyte cells produced by the methods may form a human heart muscle cell line for use in regenerative cardiology. Also described are methods of identifying functional cardiomyocyte progenitor cells and their use in therapeutic applications.