Heart VentriclesMyocardiumHeartHeart RateCerebral VentriclesThird VentricleFourth VentricleHeart FailureLateral VentriclesHeart Defects, CongenitalCerebral Ventricle NeoplasmsHeart DiseasesHeart TransplantationFetal HeartHeart AtriaMyocardial ContractionHeart ValvesVentricular FunctionVentricular Function, LeftHeart BlockEchocardiographyHemodynamicsDogsHeart Function TestsMyocytes, CardiacHeart SeptumCardiomegalyEndocardiumVentricular Function, RightStroke VolumeMyocardial Ischemia