Fig. 6. Right ventricular morphology in Cx43-PCKO hearts is grossly abnormal. (A) Grossly visible bulges flanking the OFT are seen in Cx43-PCKO hearts (black arrows) and occasionally focal bulging segments at the right ventricular apex (arrowhead). (B) Detailed view of the RVOT in a Cx43-PCKO heart demonstrates grossly bulging infundibular contour. (C) Although most Cx43-PCKO hearts have infundibular bulges (arrows), many (including this heart) lack the bulging apical segment seen in A. (D) The RVOT region of the heart in C is markedly distorted. (E,F) Control and (G,H) Cx43^fo/wt (heterozygous Cx43-null) hearts have grossly normal right ventricular and OFT morphology. Infundibular contours (outlined) form a triangular shape in the control and Cx43^fo/wt hearts as they course towards the pulmonary trunk. (I,J) Infundibular bulges (arrows) in the Cx43-PCKO OFT are similar to those of the Cx43^fo/fo (germline Cx43-null) heart. (K) Oblique view of the Cx43-PCKO RVOT demonstrates infundibular bulging above the level of the pulmonic valve. (L) By contrast, the contour of the wild-type RVOT tapers as it approaches the pulmonary trunk. P, pulmonary trunk; LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle; RVOT, right ventricular outflow tract. Scale bar: 1.2 mm for A,E,G,I,L; 750 µm for C,K; 400 µm for B,D,F,H,J.