Early Development of the Heart

The embryonic heart forms from multipotent cardiovascular progenitor cells that migrate to anterior lateral splanchnic mesoderm. The cardiac transcriptional program is activated by the combinatorial activities of multiple intercellular signaling pathways and transcription factors. Early differentiating cardiomyocytes converge at the ventral midline to give rise to the cardiac crescent and linear heart tube (HT). The HT subsequently loops to the right and extends in length by addition of cardiac progenitor cells to the cardiac poles from contiguous pharyngeal mesoderm. The embryonic heart is the template for cardiac growth and septation during the transition to the definitive four-chambered heart.