Heart AtriaHeart VentriclesCerebral VentriclesThird VentricleFourth VentricleLateral VentriclesAtrial FunctionCerebral Ventricle NeoplasmsHeartVentricular FunctionMyocardial ContractionHeart Conduction SystemDogsAtrial FibrillationMyocardiumAtrial Function, RightHeart NeoplasmsPulmonary VeinsEchocardiographyEndocardiumElectrocardiographyCardiac Pacing, ArtificialElectrophysiologic Techniques, CardiacPericardiumVentricular Function, RightHeart Defects, CongenitalCatheter AblationHeart SeptumHeart RateDouble Outlet Right VentricleSinoatrial NodeVentricular Function, LeftHydrocephalusFetal HeartVena Cava, SuperiorFistulaGuinea PigsModels, CardiovascularAtrioventricular NodeRefractory Period, ElectrophysiologicalVentricular Dysfunction, RightCerebral VentriculographyHemodynamicsCardiomegalyInjections, IntraventricularAction PotentialsBody Surface Potential MappingTransposition of Great VesselsAtrial Function, LeftAtrial Natriuretic FactorEchocardiography, TransesophagealHeart Septal Defects, VentricularEpendymaIsoproterenolCardiac Surgical ProceduresCardiac CatheterizationMyocytes, CardiacTricuspid ValveHypertrophy, Right VentricularAngiocardiographyStroke VolumeHeart AneurysmMitral ValveDiastoleAtrial FlutterBlood PressurePapillary MusclesHeart FailurePulmonary ArteryCardiac VolumeBundle of HisVentricular Dysfunction, LeftMagnetic Resonance ImagingHeart InjuriesVentricular RemodelingAnti-Arrhythmia AgentsMyxomaArrhythmias, CardiacVentricular PressurePacemaker, ArtificialSystoleRats, WistarCardiomyopathy, DilatedHeart DiseasesTachycardiaEchocardiography, DopplerCardiomyopathiesFontan ProcedureHeart BlockElectrophysiologyAtrial AppendageCoronary CirculationPerfusionEchocardiography, Doppler, ColorHeart Septal Defects, AtrialCardiotonic AgentsTricuspid AtresiaElectric StimulationTreatment OutcomeHypertrophy, Left Ventricular