The present invention provides NRP1 as a cell surface marker for isolating human cardiomyogenic ventricular progenitor cells (HVPs), in particular progenitor cells that preferentially differentiate into cardiac ventricular muscle cells. Additional HVP cell surface markers identified by single cell sequencing are also provided. The invention provides in vitro methods of the separation of NRP1+ ventricular progenitor cells, and the large scale expansion and propagation thereof. Large clonal populations of isolated NRP1+ ventricular progenitor cells are also provided. Methods of in vivo use of NRP1+ ventricular progenitor cells for cardiac repair or to improve cardiac function are also provided. Methods of using the NRP1+ ventricular progenitor cells for cardiac toxicity screening of test compounds are also provided.
