Aortic Stenosis, SupravalvularDiscrete Subaortic StenosisAortic Stenosis, SubvalvularAortic Valve StenosisWilliams SyndromePulmonary Valve StenosisElastinAortic ValveCardiomyopathy, HypertrophicVentricular Outflow ObstructionCarotid StenosisEndocardial Cushion DefectsAortic Valve InsufficiencyAortic Arch SyndromesEchocardiographyAutograftsAortic CoarctationHeart Valve Prosthesis ImplantationHeart Septal Defects, VentricularCoronary StenosisKinetocardiographyAngiocardiographySpinal StenosisHeart SeptumPericardiumHeart Defects, CongenitalTracheal StenosisCardiac CatheterizationMitral Valve StenosisAmyl NitriteEchocardiography, DopplerHeart Valve ProsthesisPyloric StenosisConstriction, PathologicTreatment OutcomeFollow-Up StudiesSyndromeMitral ValveHemodynamicsPulmonary Subvalvular StenosisReoperationRetrospective StudiesHeart VentriclesTransposition of Great VesselsPostoperative ComplicationsSeverity of Illness IndexCatheterizationSinus of ValsalvaCalcinosisMatched-Pair AnalysisInfant, NewbornTime FactorsRenal Artery ObstructionBioprosthesisBlood Flow Velocity