Cardiac ElectrophysiologyHeart FailureHeartElectrophysiological ProcessesElectrophysiologic Techniques, CardiacEpicardial MappingArrhythmias, CardiacModels, CardiovascularMyocytes, CardiacHeart Conduction SystemElectrophysiologyHeart RateVoltage-Sensitive Dye ImagingElectrophysiological PhenomenaElectrocardiographyAction PotentialsHeart VentriclesMyocardiumAtrioventricular NodeCardiac OutputCardiac Output, LowComputer SimulationCatheter AblationLong QT SyndromeHeart DiseasesCardiac Pacing, ArtificialDeath, Sudden, CardiacCardiac Surgical ProceduresMyocardial ContractionCardiomegalyHeart Failure, SystolicPotassium ChannelsHeart TransplantationStroke VolumeVentricular Function, LeftHemodynamicsTime FactorsCardiomyopathy, DilatedEchocardiographyVentricular Dysfunction, LeftVentricular RemodelingHeart Failure, DiastolicCardiomyopathiesHeart AtriaNatriuretic Peptide, BrainHeart Defects, CongenitalTreatment OutcomeMyocardial InfarctionCardiac CatheterizationCardiotonic AgentsHeart Function TestsAdrenergic beta-AntagonistsAlgorithmsDogsChronic DiseaseProspective StudiesDisease Models, AnimalFollow-Up StudiesHeart ArrestCardiac TamponadeTreatment FailureMyocardial IschemiaFetal HeartRisk FactorsRats, Sprague-DawleyBlood PressurePrognosisCalciumRetrospective StudiesBiological MarkersPacemaker, ArtificialCardiac Resynchronization TherapyPredictive Value of TestsCardiac MyosinsHeart ValvesHeart BlockCardiac VolumeExercise TestVentricular DysfunctionSystoleAtrial Natriuretic FactorMyoblasts, CardiacAtrial FibrillationDiastoleAngiotensin-Converting Enzyme InhibitorsHeart-Assist DevicesFibrosisPatch-Clamp TechniquesCardiac GlycosidesRisk AssessmentCardiac Imaging TechniquesDiureticsTroponin IVentricular FunctionVentricular PressureRats, WistarPropanolaminesAnti-Arrhythmia AgentsHospitalizationEchocardiography, Doppler