SRP343038 PRJNA773814 Transcriptional, electrophysiological, and metabolomic characterization of human embryonic stem cell derived first and second heart field cardiomyocytes The discovery of how TB5 expression in the first heart field cardiomyocytes may contribute to their maturation is a novel and important concept that may have a substantial impact on future attempts to promote human heart regeneration. This manuscript emphasizes the importance of choosing the right subtype of hESC-derived cardiomyocytes with improved maturity and functional properties for cardiac regeneration therapy.