Methods are disclosed for producing populations of cardiomyocytes from pluripotent stem cells. Populations may be enriched for either atrial or ventricular cardiomyocytes and the resulting ventricular population may be essentially free of pacemaker cells. The method includes incubating pluripotent stem cells in a suitable medium with a BMP component, and an activin component, the amounts of activin may be varied to enrich for either atrial or ventricular cardiomyocytes. The enriched populations, as well as methods of using the same to treat patients in need of cardiac repair are disclosed.