Endocardial Cushion DefectsHeart Septal DefectsHeart Septal Defects, VentricularEndocardial CushionsHeart Septal Defects, AtrialHeart Defects, CongenitalHeart ValvesHeart SeptumFetal HeartHeartEndocardiumDown SyndromeHeart RateTetralogy of FallotAortopulmonary Septal DefectEchocardiographyCardiac Surgical ProceduresAbnormalities, MultipleInfant, NewbornMyocardiumAtrial SeptumMesodermMitral Valve InsufficiencyChromosomes, Human, Pair 21Fetal DiseasesMitral ValveTransforming Growth Factor beta2Exercise TestHeart VentriclesHeart AtriaUltrasonography, PrenatalSeptal Occluder DeviceChick EmbryoGene Expression Regulation, DevelopmentalGestational AgeRetrospective StudiesPregnancyMorphogenesisEmbryologyTransforming Growth Factor beta3ReoperationTreatment OutcomeVersicans