Prospective fate of the right conal wall (classically denoted anterior conus).

(A) Representative images of embryonic heart at stage 22HH showing a black label inserted in the myocardium on the right surface of the cono-ventricular boundary (red arrowhead). (A’) Embryonic heart at stage 36HH. Visualization of small dark spots (red arrowheads) distributed in the myocardium of the apical ventricular region in relation to the anterior interventricular groove (AIVG). (B) Embryonic heart at stage 22HH with a black label inserted in the myocardium on the right surface of the conus-truncus border (red arrowheads). (B’) Embryonic heart at stage 36HH showing small dark spots (red arrowheads) distributed in the myocardium from the right region of the cardiac base to the subvalvular pulmonary region. The dotted white line indicates the limit of the right ventricular-free wall. Abbreviations: AIVG = anterior interventricular groove; As = atrial segment; C = conus; IVS = interventricular septum; LA = left atrium; LV = left ventricle; PA = pulmonary artery, RA = right atrium; RV = right ventricle; T = truncus, Vs = ventricular segment.