Dotychczas bezobjawowe dwumiesięczne niemowlę z unikatową prezentacją trójprzedsionkowego lewego serca, prawego częściowego nieprawidłowego spływu żył płucnych oraz krytycznej nadzastawkowej stenozy mitralnej

Major developments in diagnostic techniques in pre- and neonatal care have significantly reduced the rate of undetected congenital heart defects (CHD). Despite such advances, several patients with critical congenital heart defects are discharged annually from neonatal units with no proper diagnosis or treatment. We present the case of a two month-old originally asymptomatic girl who represents the perfect example of such a situation. The infant was diagnosed just after pulmonary and cardiovascular decompensation with critical, complex CHD. The absence of disease symptoms of occurred due to a rare and specific morphology of pulmonary vessels and intracardiac membranes.