Heart VentriclesMyocardiumHeartHeart FailureHeart RateCerebral VentriclesThird VentricleFourth VentricleLateral VentriclesHeart Defects, CongenitalTreatment FailureHeart DiseasesCerebral Ventricle NeoplasmsHeart TransplantationFetal HeartHeart AtriaMyocardial ContractionVentricular Function, LeftHeart ValvesVentricular FunctionHemodynamicsEchocardiographyTime FactorsStroke VolumeDogsCardiac Output, LowCardiomyopathy, DilatedCardiomegalyHeart BlockHeart Function TestsVentricular RemodelingTreatment OutcomeKidney Failure, ChronicCardiomyopathiesMyocardial IschemiaHeart Failure, SystolicHeart SeptumVentricular Function, RightFailure to ThriveMyocytes, CardiacMyocardial InfarctionEndocardiumCardiac Pacing, Artificial