Overview of zebrafish heart development. By 14 hpf, cardiac progenitors have emerged from the anterior lateral plate mesoderm. These cardiac precursors migrate and fuse at the midline to form a cone structure by 19 hpf. After one day of development, a beating linear heart tube has formed to propel circulation through the body. Cardiac chambers are clearly demarcated and looping has completed after two days of development.VM, ventricle myocardium; AM, atrium myocardium; EC, endocardium; (upper panel) stage of development and hour postfertalisation, hpf, and (lower panel) genes that regulate the developmental processes. Gata5, Transcription factor required during cardiovascular development; Hand2, Heart And Neural Crest Derivatives Expressed 2;Tbx20, T-Box Transcription Factor; Smarcd3,4, SWI/SNF Related, Matrix Associated, Actin Dependent Regulator Of Chromatin, Subfamily D, Member 3and 4; CTR1, copper transporter; Cdc37, Cell Division Cycle 37; RTF1, Paf1, LEO1, RNA Polymerase II Complex Component.