Heart FailureTwinsDiseases in TwinsTwins, MonozygoticHeartTwins, ConjoinedTwins, DizygoticHeart RateCardiac Output, LowHeart Failure, SystolicTwin Studies as TopicHeart Failure, DiastolicPregnancy, TwinStroke VolumeMyocardiumHeart DiseasesHeart TransplantationCardiomyopathy, DilatedNatriuretic Peptide, BrainVentricular Function, LeftVentricular Dysfunction, LeftHemodynamicsTreatment FailureChronic DiseaseAdrenergic beta-AntagonistsVentricular RemodelingHeart Defects, CongenitalTreatment OutcomeEchocardiographyCardiotonic AgentsMyocardial ContractionTime FactorsCardiac Pacing, ArtificialFollow-Up StudiesProspective StudiesRisk FactorsHeart Function TestsCardiomyopathiesCardiomegalyMyocardial InfarctionMyocytes, CardiacPrognosisDiureticsAngiotensin-Converting Enzyme InhibitorsHeart AtriaFetal HeartHeart-Assist DevicesHospitalizationMyocardial IschemiaPropanolaminesExercise TestRetrospective StudiesSystoleBiological MarkersDisease Models, AnimalSeverity of Illness IndexDiastoleHeart ValvesHeart VentriclesPredictive Value of TestsDogsExercise ToleranceDigoxinKidney Failure, ChronicPregnancy, MultipleAtrial Natriuretic FactorVentricular DysfunctionCohort StudiesCarbazolesRisk AssessmentSympathetic Nervous SystemOxygen ConsumptionPatient ReadmissionHeart BlockEchocardiography, DopplerProportional Hazards ModelsVentricular PressureCardiovascular AgentsDouble-Blind MethodPulmonary Wedge PressureSurvival AnalysisMineralocorticoid Receptor AntagonistsFailure to ThriveBlood PressureMetoprololSpironolactoneSurvival RatePacemaker, ArtificialCardiac Resynchronization TherapyCoronary DiseaseElectrocardiographyNorepinephrineAcute DiseaseDisease ProgressionAtrial FibrillationVasodilator AgentsDeath, Sudden, CardiacFibrosisCardio-Renal SyndromeFetofetal Transfusion