Fig. 1

Gross pathology of the heart. a Severe dilation of the right atrium, right atrial appendage and right ventricle, as seen from the right. b An inside view of the right heart showing severe dilation of the right atrium with a dysplastic tricuspid valve consisting of marked hypoplasia of the chordae tendineae, and thick, deformed, and malpositioned valve leaflets. Note the large accessory orifice (arrowhead) of the double-orifice tricuspid valve. The arrow indicates the normal right ventricular inflow tract. c An inside view of the left heart demonstrating the prominent trabeculation of the left ventricular free wall and a marked hypoplastic and branched papillary muscle (Ao, aorta; IVS, interventricular septum; L-At, left atrium; L-Au, left atrial appendage; LV, left ventricle; LV-Fr, left ventricular free wall; PA, pulmonary artery; R-At, right atrium; R-Au, right atrial appendage; RV, right ventricle)