The image represents the post-mortem heart of a 28-year-old female patient, diagnosed in childhood with complete common atrioventricular canal defect. At time of diagnosis, the family refused surgery, as did the patient during her adulthood. Despite being advised against pregnancy, she became pregnant. On presentation to hospital, she was cyanotic, with clubbed fingers, and hemodynamically unstable, in sinus rhythm, with Eisenmenger syndrome and respiratory failure partially responsive to oxygen. During pregnancy, owing to systemic vasodilatation, the right-to-left shunt is increased, with more severe cyanosis and low cardiac output. Echocardiography revealed the complete common atrioventricular canal defect, with a single atrioventricular valve with severe regurgitation, right ventricular hypertrophy, pulmonary artery dilatation, severe pulmonary hypertension and a hypoplastic left ventricle. The gestational age at delivery was 38 weeks. She gave birth to a healthy boy, with an Apgar score of 10. The vaginal delivery was chosen by an interdisciplinary team. The cesarean delivery and the anesthesia were considered too risky compared to vaginal delivery. Three days later, the patient died. The autopsy revealed hepatomegaly, a greatly hypertrophied right ventricle with a purplish clot ascending the dilated pulmonary arteries and a hypoplastic left ventricle with a narrowed chamber. A single valve was observed between the atria and ventricles, making all four heart chambers communicate, also insufficiently developed interventricular septum and its congenital absence in the cranial third. These morphological changes indicate the complete common atrioventricular canal defect, with right ventricular dominance, which is a rare and impressive malformation that requires mandatory treatment in early childhood in order for the condition to be solved.