Fuente: WIPO "tomato" A cardiomyocyte population comprising cardiomyocytes differentiated from human pluripotent stem cells and having the following features (1), (2), and (3): (1) cells positive for cardiac troponin T constitute 90% or more of all viable cells,; (2) the spontaneous beating rate is 0 to 60 beats per minute; and (3) the population of cardiomyocyte is within 30 days from initiation of differentiation. Also provided is a pharmaceutical composition comprising the cardiomyocyte population and/or a cardiac spheroid obtained by spheroidizing the cardiomyocyte population, and a pharmaceutically acceptable carrier. Further provided is a method for producing the cardiomyocyte population, the method comprising: (a) expanding human pluripotent stem cells in culture; (b) culturing the expanded human pluripotent stem cells under conditions for differentiation into cardiomyocytes to produce a cell population comprising 60% or more cardiomyocytes; and (c) removing human pluripotent stem cells and non-cardiomyocyte cells from the cell population.